[The protective effect of XD in ConA-induced liver injury].

PubMed

Liu, Xiao-Bin; Wang, Jing; Zhang, Qian-Qian; Liu, Tao; Dang, Tong-Mei; Cao, Yi-Ming

2010-12-01

To explore the protective effect and its mechanism of Modified Xiaochaihu decoction(MXD) in the liver injury of mice. METHORDS: Using Reitman methord to examine serum ALT and ATS; Using sandwich enzyme immunoassay ABC-ELISA to examine serum TNF-α and IFN-γ. Serum ALT and ATS of MXD large dose group and Xiaochaihu decoction (XD )group were lower than that of animal models group, there was significant difference among groups (P<0.05). There were not significant difference (P>0.05) between serum ALT and ATS of MXD small dose group and that of animal models group; MXD large dose group, XD group and Biphenyldimethylesterate (DDB) group are similar, no difference (P>0.05). Serum TNF-α and IFN-γ of MXD large dose group and XD group were significant lower than that of animal models group, there was significant difference among groups (P<0.05). Serum TNF-α and IFN-γ of XD group ware higher than that of MXD large dose group, there was significant difference among groups (P<0.05). MXD large dose group, XD group and DDB group were similar, no difference. Xiaocaihu decoction possesses the effect of pro2 tection of hepatic impairment and the protective mechanism might be associated with the inhibition of apoptosis and immunomodulation.

Testing Pullout Strength of Pedicle Screw Using Synthetic Bone Models: Is a Bilayer Foam Model a Better Representation of Vertebra?

PubMed

Varghese, Vicky; Krishnan, Venkatesh; Saravana Kumar, Gurunathan

2018-06-01

A biomechanical study. A new biomechanical model of the vertebra has been developed that accounts for the inhomogeneity of bone and the contribution of the pedicle toward the holding strength of a pedicle screw. Pullout strength studies are typically carried out on rigid polyurethane foams that represent the homogeneous vertebral framework of the spine. However, the contribution of the pedicle region, which contributes to the inhomogeneity in this framework, has not been considered in previous investigations. Therefore, we propose a new biomechanical model that can account for the vertebral inhomogeneity, especially the contribution of the pedicles toward the pullout strength of the pedicle screw. A bilayer foam model was developed by joining two foams representing the pedicle and the vertebra. The results of the pullout strength tests performed on the foam models were compared with those from the tests performed on the cadaver lumbar vertebra. Significant differences ( p <0.05) were observed between the pullout strength of the pedicle screw in extremely osteoporotic (0.18±0.11 kN), osteoporotic (0.37±0.14 kN), and normal (0.97±0.4 kN) cadaver vertebra. In the monolayer model, significant differences ( p <0.05) were observed in pullout strength between extremely osteoporotic (0.3±0.02 kN), osteoporotic (0.65±0.12 kN), and normal (0.99±0.04 kN) bone model. However, the bilayer foam model exhibited no significant differences ( p >0.05) in the pullout strength of pedicle screws between osteoporotic (0.85±0.08 kN) and extremely osteoporotic bone models (0.94±0.08 kN), but there was a significant difference ( p <0.05) between osteoporotic (0.94±0.08 kN) and normal bone models (1.19±0.05 kN). There were no significant differences ( p >0.05) in pullout strength between cadaver and bilayer foam model in normal bones. The new synthetic bone model that reflects the contribution of the pedicles to the pullout strength of the pedicle screws could provide a more efficacious means of testing pedicle-screw pullout strength. The bilayer model can match the pullout strength value of normal lumbar vertebra bone whereas the monolayer foam model was able to match that of the extremely osteoporotic lumbar vertebra.

Use of a vision model to quantify the significance of factors effecting target conspicuity

NASA Astrophysics Data System (ADS)

Gilmore, M. A.; Jones, C. K.; Haynes, A. W.; Tolhurst, D. J.; To, M.; Troscianko, T.; Lovell, P. G.; Parraga, C. A.; Pickavance, K.

2006-05-01

When designing camouflage it is important to understand how the human visual system processes the information to discriminate the target from the background scene. A vision model has been developed to compare two images and detect differences in local contrast in each spatial frequency channel. Observer experiments are being undertaken to validate this vision model so that the model can be used to quantify the relative significance of different factors affecting target conspicuity. Synthetic imagery can be used to design improved camouflage systems. The vision model is being used to compare different synthetic images to understand what features in the image are important to reproduce accurately and to identify the optimum way to render synthetic imagery for camouflage effectiveness assessment. This paper will describe the vision model and summarise the results obtained from the initial validation tests. The paper will also show how the model is being used to compare different synthetic images and discuss future work plans.

Micro-CT evaluation of the marginal fit of CAD/CAM all ceramic crowns

NASA Astrophysics Data System (ADS)

Brenes, Christian

Objectives: Evaluate the marginal fit of CAD/CAM all ceramic crowns made from lithium disilicate and zirconia using two different fabrication protocols (model and model-less). METHODS: Forty anterior all ceramic restorations (20 lithium disilicate, 20 zirconia) were fabricated using a CEREC Bluecam scanner. Two different fabrication methods were used: a full digital approach and a printed model. Completed crowns were cemented and marginal gap was evaluated using Micro-CT. Each specimen was analyzed in sagittal and trans-axial orientations, allowing a 360° evaluation of the vertical and horizontal fit. RESULTS: Vertical measurements in the lingual, distal and mesial views had and estimated marginal gap from 101.9 to 133.9 microns for E-max crowns and 126.4 to 165.4 microns for zirconia. No significant differences were found between model and model-less techniques. CONCLUSION: Lithium disilicate restorations exhibited a more accurate and consistent marginal adaptation when compared to zirconia crowns. No statistically significant differences were observed when comparing model or model-less approaches.

Water-based condensation particle counters comparison near a major freeway with significant heavy-duty diesel traffic

NASA Astrophysics Data System (ADS)

Lee, Eon S.; Polidori, Andrea; Koch, Michael; Fine, Philip M.; Mehadi, Ahmed; Hammond, Donald; Wright, Jeffery N.; Miguel, Antonio. H.; Ayala, Alberto; Zhu, Yifang

2013-04-01

This study compares the instrumental performance of three TSI water-based condensation particle counter (WCPC) models measuring particle number concentrations in close proximity (15 m) to a major freeway that has a significant level of heavy-duty diesel traffic. The study focuses on examining instrument biases and performance differences by different WCPC models under realistic field operational conditions. Three TSI models (3781, 3783, and 3785) were operated for one month in triplicate (nine units in total) in parallel with two sets of Scanning Mobility Particle Sizer (SMPS) spectrometers for the concurrent measurement of particle size distributions. Inter-model bias under different wind directions were first evaluated using 1-min raw data. Although all three WCPC models agreed well in upwind conditions (lower particle number concentrations, in the range of 103-104 particles cm-3), the three models' responses were significantly different under downwind conditions (higher particle number concentrations, above 104 particles cm-3). In an effort to increase inter-model linear correlations, we evaluated the results of using longer averaging time intervals. An averaging time of at least 15 min was found to achieve R2 values of 0.96 or higher when comparing all three models. Similar results were observed for intra-model comparisons for each of the three models. This strong linear relationship helped identify instrument bias related to particle number concentrations and particle size distributions. The TSI 3783 produced the highest particle counts, followed by TSI 3785, which reported 11% lower during downwind conditions than TSI 3783. TSI 3781 recorded particle number concentrations that were 24% lower than those observed by TSI 3783 during downwind condition. We found that TSI 3781 underestimated particles with a count median diameter less than 45 nm. Although the particle size dependency of instrument performance was found the most significant in TSI 3781, both models 3783 and 3785 showed somewhat size dependency. In addition, within each tested WCPC model, one unit was found to count significantly different and be more sensitive to particle size than the other two. Finally, exponential regression analysis was used to numerically quantify instrumental inter-model bias. Correction equations are proposed to adjust the TSI 3781 and 3785 data to the most recent model TSI 3783.

H2-based star formation laws in hierarchical models of galaxy formation

NASA Astrophysics Data System (ADS)

Xie, Lizhi; De Lucia, Gabriella; Hirschmann, Michaela; Fontanot, Fabio; Zoldan, Anna

2017-07-01

We update our recently published model for GAlaxy Evolution and Assembly (GAEA), to include a self-consistent treatment of the partition of cold gas in atomic and molecular hydrogen. Our model provides significant improvements with respect to previous ones used for similar studies. In particular, GAEA (I) includes a sophisticated chemical enrichment scheme accounting for non-instantaneous recycling of gas, metals and energy; (II) reproduces the measured evolution of the galaxy stellar mass function; (III) reasonably reproduces the observed correlation between galaxy stellar mass and gas metallicity at different redshifts. These are important prerequisites for models considering a metallicity-dependent efficiency of molecular gas formation. We also update our model for disc sizes and show that model predictions are in nice agreement with observational estimates for the gas, stellar and star-forming discs at different cosmic epochs. We analyse the influence of different star formation laws including empirical relations based on the hydrostatic pressure of the disc, analytic models and prescriptions derived from detailed hydrodynamical simulations. We find that modifying the star formation law does not affect significantly the global properties of model galaxies, neither their distributions. The only quantity showing significant deviations in different models is the cosmic molecular-to-atomic hydrogen ratio, particularly at high redshift. Unfortunately, however, this quantity also depends strongly on the modelling adopted for additional physical processes. Useful constraints on the physical processes regulating star formation can be obtained focusing on low-mass galaxies and/or at higher redshift. In this case, self-regulation has not yet washed out differences imprinted at early time.

Azimuth cut-off model for significant wave height investigation along coastal water of Kuala Terengganu, Malaysia

NASA Astrophysics Data System (ADS)

Marghany, Maged; Ibrahim, Zelina; Van Genderen, Johan

2002-11-01

The present work is used to operationalize the azimuth cut-off concept in the study of significant wave height. Three ERS-1 images have been used along the coastal waters of Terengganu, Malaysia. The quasi-linear transform was applied to map the SAR wave spectra into real ocean wave spectra. The azimuth cut-off was then used to model the significant wave height. The results show that azimuth cut-off varied with the different period of the ERS-1 images. This is because of the fact that the azimuth cut-off is a function of wind speed and significant wave height. It is of interest to find that the significant wave height modeled from azimuth cut-off is in good relation with ground wave conditions. It can be concluded that ERS-1 can be used as a monitoring tool in detecting the significant wave height variation. The azimuth cut-off can be used to model the significant wave height. This means that the quasi-linear transform could be a good application to significant wave height variation during different seasons.

Evaluation of different time domain peak models using extreme learning machine-based peak detection for EEG signal.

PubMed

Adam, Asrul; Ibrahim, Zuwairie; Mokhtar, Norrima; Shapiai, Mohd Ibrahim; Cumming, Paul; Mubin, Marizan

2016-01-01

Various peak models have been introduced to detect and analyze peaks in the time domain analysis of electroencephalogram (EEG) signals. In general, peak model in the time domain analysis consists of a set of signal parameters, such as amplitude, width, and slope. Models including those proposed by Dumpala, Acir, Liu, and Dingle are routinely used to detect peaks in EEG signals acquired in clinical studies of epilepsy or eye blink. The optimal peak model is the most reliable peak detection performance in a particular application. A fair measure of performance of different models requires a common and unbiased platform. In this study, we evaluate the performance of the four different peak models using the extreme learning machine (ELM)-based peak detection algorithm. We found that the Dingle model gave the best performance, with 72 % accuracy in the analysis of real EEG data. Statistical analysis conferred that the Dingle model afforded significantly better mean testing accuracy than did the Acir and Liu models, which were in the range 37-52 %. Meanwhile, the Dingle model has no significant difference compared to Dumpala model.

Comparing live and remote models in eating conformity research.

PubMed

Feeney, Justin R; Polivy, Janet; Pliner, Patricia; Sullivan, Margot D

2011-01-01

Research demonstrates that people conform to how much other people eat. This conformity occurs in the presence of other people (live model) and when people view information about how much food prior participants ate (remote models). The assumption in the literature has been that remote models produce a similar effect to live models, but this has never been tested. To investigate this issue, we randomly paired participants with a live or remote model and compared their eating to those who ate alone. We found that participants exposed to both types of model differed significantly from those in the control group, but there was no significant difference between the two modeling procedures. Crown Copyright © 2010. Published by Elsevier Ltd. All rights reserved.

Retinal, functional, and morphological comparisons of two different macaque species, Macaca mulatta and Macaca fasicularis, for models of laser eye injury

NASA Astrophysics Data System (ADS)

DiCarlo, Cheryl D.; Hacker, Henry D.; Brown, Araceli; Cheramie, Rachael; Martinsen, Gary L.; Rockwell, Benjamin; Stuck, Bruce E.

2005-04-01

The past several years has seen a severe shortage of pathogen-free Indian origin rhesus macaques due to the increased requirement for this model in retroviral research. With greater than 30 years of research data accumulated using the Rhesus macaque as the model for laser eye injury there exists a need to bridge to a more readily available nonhuman primate model. Much of the data previously collected from the Rhesus monkey (Macaca mulatta) provided the basis for the American National Standards Institute (ANSI) standards for laser safety. Currently a Tri-service effort is underway to utilize the Cynomolgus monkey (Macaca fasicularis) as a replacement for the Rhesus macaque. Preliminary functional and morphological baseline data collected from multifocal electroretinography (mfERG), optical coherence tomography (OCT) and retinal cell counts were compared from a small group of monkeys and tissues to determine if significant differences existed between the species. Initial functional findings rom mfERG yielded only one difference for the n2 amplitude value which was greater in the Cynomolgus monkey. No significant differences were seen in retinal and foveal thickness, as determined by OCT scans and no significant differences were seen in ganglion cell and inner nuclear cell nuclei counts. A highly significant difference was seen in the numbers of photoreceptor nuclei with greater numbers in the Rhesus macaque. This indicates more studies should be performed to determine the impact that a model change would have on the laser bioeffects community and their ability to continue to provide minimal visible lesion data for laser safety standards. The continued goal of this project will be to provide that necessary baseline information for a seamless transition to a more readily available animal model.

[COMPARISON OF FEMORAL CONDYLAR TWIST ANGLE IN THREE DIMENSIONAL RECONSTRUCTION DIGITAL MODELS OF KNEE JOINT BASED ON TWO DIMENSIONAL IMAGES OF MRI AND CT].

PubMed

Huang, Zan; Li, Yanlin; Hu, Meng; Li, Jian; You, Zhimin; Wang, Guoliang; He, Chuan

2015-02-01

To study the difference of femoral condylar twist angle (CTA) measurement in three dimensional (3-D) reconstruction digital models of human knee joint based on the two dimensional (2-D) images of MRI and CT so as to provide a reference for selecting the best method of CTA measurement in preoperative design for the femoral prosthesis rotational position. The CTA of 10 human cadaveric knee joint was measured in 3-D digital models based on MRI (group A), in 3-D digital models based on CT (group B), in the cadaveric knee joint with cartilage (group C), and in the cadaveric knee joint without cartilage (group D), respectively. The statistical analysis of the differences was made among the measurements of the CTA. The CTA values measured in 3-D digital models were (6.43 ± 0.53) degrees in group A and (3.31 ± 1.07) degrees in group B, showing significant difference (t = 10.235, P = 0.000). The CTA values measured in the cadaveric knee joint were (5.21 ± 1.28) degrees in group C and (3.33 ± 1.12) degrees in group D, showing significant difference (t = 5.770, P = 0.000). There was significant difference in the CTA values between group B and group C (t = 5.779, P = 0.000), but no significant difference was found between group A and group C (t = 3.219, P = 0.110). The CTA values measured in the 3-D digital models based on MRI are closer to the actual values measured in the knee joint with cartilage, and benefit for preoperative plan.

Interactions of donor sources and media influence the histo-morphological quality of full-thickness skin models.

PubMed

Lange, Julia; Weil, Frederik; Riegler, Christoph; Groeber, Florian; Rebhan, Silke; Kurdyn, Szymon; Alb, Miriam; Kneitz, Hermann; Gelbrich, Götz; Walles, Heike; Mielke, Stephan

2016-10-01

Human artificial skin models are increasingly employed as non-animal test platforms for research and medical purposes. However, the overall histopathological quality of such models may vary significantly. Therefore, the effects of manufacturing protocols and donor sources on the quality of skin models built-up from fibroblasts and keratinocytes derived from juvenile foreskins is studied. Histo-morphological parameters such as epidermal thickness, number of epidermal cell layers, dermal thickness, dermo-epidermal adhesion and absence of cellular nuclei in the corneal layer are obtained and scored accordingly. In total, 144 full-thickness skin models derived from 16 different donors, built-up in triplicates using three different culture conditions were successfully generated. In univariate analysis both media and donor age affected the quality of skin models significantly. Both parameters remained statistically significant in multivariate analyses. Performing general linear model analyses we could show that individual medium-donor-interactions influence the quality. These observations suggest that the optimal choice of media may differ from donor to donor and coincides with findings where significant inter-individual variations of growth rates in keratinocytes and fibroblasts have been described. Thus, the consideration of individual medium-donor-interactions may improve the overall quality of human organ models thereby forming a reproducible test platform for sophisticated clinical research. Copyright © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

DCE-MRI of hepatocellular carcinoma: perfusion quantification with Tofts model versus shutter-speed model--initial experience.

PubMed

Jajamovich, Guido H; Huang, Wei; Besa, Cecilia; Li, Xin; Afzal, Aneela; Dyvorne, Hadrien A; Taouli, Bachir

2016-02-01

To quantify hepatocellular carcinoma (HCC) perfusion and flow with the fast exchange regime-allowed Shutter-Speed model (SSM) compared to the Tofts model (TM). In this prospective study, 25 patients with HCC underwent DCE-MRI. ROIs were placed in liver parenchyma, portal vein, aorta and HCC lesions. Signal intensities were analyzed employing dual-input TM and SSM models. ART (arterial fraction), K (trans) (contrast agent transfer rate constant from plasma to extravascular extracellular space), ve (extravascular extracellular volume fraction), kep (contrast agent intravasation rate constant), and τi (mean intracellular water molecule lifetime) were compared between liver parenchyma and HCC, and ART, K (trans), v e and k ep were compared between models using Wilcoxon tests and limits of agreement. Test-retest reproducibility was assessed in 10 patients. ART and v e obtained with TM; ART, ve, ke and τi obtained with SSM were significantly different between liver parenchyma and HCC (p < 0.04). Parameters showed variable reproducibility (CV range 14.7-66.5% for both models). Liver K (trans) and ve; HCC ve and kep were significantly different when estimated with the two models (p < 0.03). Our results show differences when computed between the TM and the SSM. However, these differences are smaller than parameter reproducibilities and may be of limited clinical significance.

Student Perceptions of Integrative Field Seminar: A Comparison of Three Models

ERIC Educational Resources Information Center

Harris, Helen; Myers, Dennis

2013-01-01

Student perceptions of 63 concentration year MSW students, grades, and faculty perceptions were examined to evaluate differences in educational outcomes and in learning experiences among a traditional classroom model, a mixed or hybrid model, and a webinar online model for delivery of integrative field seminars. No significant differences were…

Parametrized modified gravity and the CMB bispectrum

NASA Astrophysics Data System (ADS)

Di Valentino, Eleonora; Melchiorri, Alessandro; Salvatelli, Valentina; Silvestri, Alessandra

2012-09-01

We forecast the constraints on modified theories of gravity from the cosmic microwave background (CMB) anisotropies bispectrum that arises from correlations between lensing and the Integrated Sachs-Wolfe effect. In models of modified gravity the evolution of the metric potentials is generally altered and the contribution to the CMB bispectrum signal can differ significantly from the one expected in the standard cosmological model. We adopt a parametrized approach and focus on three different classes of models: Linder’s growth index, Chameleon-type models, and f(R) theories. We show that the constraints on the parameters of the models will significantly improve with future CMB bispectrum measurements.

Response of different regional online coupled models to aerosol-radiation interactions

NASA Astrophysics Data System (ADS)

Forkel, Renate; Balzarini, Alessandra; Brunner, Dominik; Baró, Rocio; Curci, Gabriele; Hirtl, Marcus; Honzak, Luka; Jiménez-Guerrero, Pedro; Jorba, Oriol; Pérez, Juan L.; Pirovano, Guido; San José, Roberto; Schröder, Wolfram; Tuccella, Paolo; Werhahn, Johannes; Wolke, Ralf; Žabkar, Rahela

2016-04-01

The importance of aerosol-meteorology interactions and their representation in online coupled regional atmospheric chemistry-meteorology models was investigated in COST Action ES1004 (EuMetChem, http://eumetchem.info/). Case study results from different models (COSMO-Muscat, COSMO-ART, and different configurations of WRF-Chem), which were applied for Europe as a coordinated exercise for the year 2010, are analyzed with respect to inter-model variability and the response of the different models to direct and indirect aerosol-radiation interactions. The main focus was on two episodes - the Russian heat wave and wildfires episode in July/August 2010 and a period in October 2010 with enhanced cloud cover and rain and including an of Saharan dust transport to Europe. Looking at physical plausibility the decrease in downward solar radiation and daytime temperature due to the direct aerosol effect is robust for all model configurations. The same holds for the pronounced decrease in cloud water content and increase in solar radiation for cloudy conditions and very low aerosol concentrations that was found for WRF-Chem when aerosol cloud interactions were considered. However, when the differences were tested for statistical significance no significant differences in mean solar radiation and mean temperature between the baseline case and the simulations including the direct and indirect effect from simulated aerosol concentrations were found over Europe for the October episode. Also for the fire episode differences between mean temperature and radiation from the simulations with and without the direct aerosol effect were not significant for the major part of the modelling domain. Only for the region with high fire emissions in Russia, the differences in mean solar radiation and temperature due to the direct effect were found to be significant during the second half of the fire episode - however only for a significance level of 0.1. The few observational data indicate that the inclusion of aerosol radiative effects improves simulated temperatures in this area. In summary, the direct aerosol effect leads to lower temperatures and PBL heights for all seasons whereas the impact of the aerosol indirect effect on temperature and pollutant concentrations over Northern Europe was found to depend strongly on the season. It cannot be generalized whether the inclusion of aerosol radiative effects and aerosol cloud interactions based on simulated aerosol concentrations does improve the simulation results. Furthermore, assumptions how aerosol optical properties are calculated, i.e. on the aerosol's mixing state have a strong effect on simulated aerosol optical depth and the aerosol effect on incoming solar radiation and temperature. The inter-model variation of the response of different online coupled models suggests that further work comparing the methodologies and parameterizations used to represent the direct and indirect aerosol effect in these models is still necessary.

The Future of Drought in the Southeastern U.S.: Projections from downscaled CMIP5 models

NASA Astrophysics Data System (ADS)

Keellings, D.; Engstrom, J.

2017-12-01

The Southeastern U.S. has been repeatedly impacted by severe droughts that have affected the environment and economy of the region. In this study the ability of 32 downscaled CMIP5 models, bias corrected using localized constructed analogs (LOCA), to simulate historical observations of dry spells from 1950-2005 are assessed using Perkins skill scores and significance tests. The models generally simulate the distribution of dry days well but there are significant differences between the ability of the best and worst performing models, particularly when it comes to the upper tail of the distribution. The best and worst performing models are then projected through 2099, using RCP 4.5 and 8.5, and estimates of 20 year return periods are compared. Only the higher skill models provide a good estimate of extreme dry spell lengths with simulations of 20 year return values within ± 5 days of observed values across the region. Projected return values differ by model grouping, but all models exhibit significant increases.

Alternans promotion in cardiac electrophysiology models by delay differential equations.

PubMed

Gomes, Johnny M; Dos Santos, Rodrigo Weber; Cherry, Elizabeth M

2017-09-01

Cardiac electrical alternans is a state of alternation between long and short action potentials and is frequently associated with harmful cardiac conditions. Different dynamic mechanisms can give rise to alternans; however, many cardiac models based on ordinary differential equations are not able to reproduce this phenomenon. A previous study showed that alternans can be induced by the introduction of delay differential equations (DDEs) in the formulations of the ion channel gating variables of a canine myocyte model. The present work demonstrates that this technique is not model-specific by successfully promoting alternans using DDEs for five cardiac electrophysiology models that describe different types of myocytes, with varying degrees of complexity. By analyzing results across the different models, we observe two potential requirements for alternans promotion via DDEs for ionic gates: (i) the gate must have a significant influence on the action potential duration and (ii) a delay must significantly impair the gate's recovery between consecutive action potentials.

Gender and Acceptance of E-Learning: A Multi-Group Analysis Based on a Structural Equation Model among College Students in Chile and Spain.

PubMed

Ramírez-Correa, Patricio E; Arenas-Gaitán, Jorge; Rondán-Cataluña, F Javier

2015-01-01

The scope of this study was to evaluate whether the adoption of e-learning in two universities, and in particular, the relationship between the perception of external control and perceived ease of use, is different because of gender differences. The study was carried out with participating students in two different universities, one in Chile and one in Spain. The Technology Acceptance Model was used as a theoretical framework for the study. A multi-group analysis method in partial least squares was employed to relate differences between groups. The four main conclusions of the study are: (1) a version of the Technology Acceptance Model has been successfully used to explain the process of adoption of e-learning at an undergraduate level of study; (2) the finding of a strong and significant relationship between perception of external control and perception of ease of use of the e-learning platform; (3) a significant relationship between perceived enjoyment and perceived ease of use and between results demonstrability and perceived usefulness is found; (4) the study indicates a few statistically significant differences between males and females when adopting an e-learning platform, according to the tested model.

User-experience surveys with maternity services: a randomized comparison of two data collection models.

PubMed

Bjertnaes, Oyvind Andresen; Iversen, Hilde Hestad

2012-08-01

To compare two ways of combining postal and electronic data collection for a maternity services user-experience survey. Cross-sectional survey. Maternity services in Norway. All women who gave birth at a university hospital in Norway between 1 June and 27 July 2010. Patients were randomized into the following groups (n= 752): Group A, who were posted questionnaires with both electronic and paper response options for both the initial and reminder postal requests; and Group B, who were posted questionnaires with an electronic response option for the initial request, and both electronic and paper response options for the reminder postal request. Response rate, the amount of difference in background variables between respondents and non-respondents, main study results and estimated cost-effectiveness. The final response rate was significantly higher in Group A (51.9%) than Group B (41.1%). None of the background variables differed significantly between the respondents and non-respondents in Group A, while two variables differed significantly between the respondents and non-respondents in Group B. None of the 11 user-experience scales differed significantly between Groups A and B. The estimated costs per response for the forthcoming national survey was €11.7 for data collection Model A and €9.0 for Model B. The model with electronic-only response option in the first request had lowest response rate. However, this model performed equal to the other model on non-response bias and better on estimated cost-effectiveness, and is the better of the two models in large-scale user experiences surveys with maternity services.

The effect of visual representation style in problem-solving: a perspective from cognitive processes.

PubMed

Nyamsuren, Enkhbold; Taatgen, Niels A

2013-01-01

Using results from a controlled experiment and simulations based on cognitive models, we show that visual presentation style can have a significant impact on performance in a complex problem-solving task. We compared subject performances in two isomorphic, but visually different, tasks based on a card game of SET. Although subjects used the same strategy in both tasks, the difference in presentation style resulted in radically different reaction times and significant deviations in scanpath patterns in the two tasks. Results from our study indicate that low-level subconscious visual processes, such as differential acuity in peripheral vision and low-level iconic memory, can have indirect, but significant effects on decision making during a problem-solving task. We have developed two ACT-R models that employ the same basic strategy but deal with different presentations styles. Our ACT-R models confirm that changes in low-level visual processes triggered by changes in presentation style can propagate to higher-level cognitive processes. Such a domino effect can significantly affect reaction times and eye movements, without affecting the overall strategy of problem solving.

The Effect of Visual Representation Style in Problem-Solving: A Perspective from Cognitive Processes

PubMed Central

Nyamsuren, Enkhbold; Taatgen, Niels A.

2013-01-01

Using results from a controlled experiment and simulations based on cognitive models, we show that visual presentation style can have a significant impact on performance in a complex problem-solving task. We compared subject performances in two isomorphic, but visually different, tasks based on a card game of SET. Although subjects used the same strategy in both tasks, the difference in presentation style resulted in radically different reaction times and significant deviations in scanpath patterns in the two tasks. Results from our study indicate that low-level subconscious visual processes, such as differential acuity in peripheral vision and low-level iconic memory, can have indirect, but significant effects on decision making during a problem-solving task. We have developed two ACT-R models that employ the same basic strategy but deal with different presentations styles. Our ACT-R models confirm that changes in low-level visual processes triggered by changes in presentation style can propagate to higher-level cognitive processes. Such a domino effect can significantly affect reaction times and eye movements, without affecting the overall strategy of problem solving. PMID:24260415

Evaluating the agreement between measurements and models of net ecosystem exchange at different times and timescales using wavelet coherence: an example using data from the North American Carbon Program Site-Level Interim Synthesis

Treesearch

P.C. Stoy; M.C. Dietze; A.D. Richardson; R. Vargas; A.G. Barr; R.S. Anderson; M.A. Arain; I.T. Baker; T.A. Black; J.M. Chen; R.B. Cook; C.M. Gough; R.F. Grant; D.Y. Hollinger; R.C. Izaurralde; C.J. Kucharik; P. Lafleur; B.E. Law; S. Liu; E. Lokupitiya; Y. Luo; J. W. Munger; C. Peng; B. Poulter; D.T. Price; D. M. Ricciuto; W. J. Riley; A. K. Sahoo; K. Schaefer; C.R. Schwalm; H. Tian; H. Verbeeck; E. Weng

2013-01-01

Earth system processes exhibit complex patterns across time, as do the models that seek to replicate these processes. Model output may or may not be significantly related to observations at different times and on different frequencies. Conventional model diagnostics provide an aggregate view of model-data agreement, but usually do not identify the time and frequency...

Comparison of Vehicle Choice Models

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

Stephens, Thomas S.; Levinson, Rebecca S.; Brooker, Aaron

Five consumer vehicle choice models that give projections of future sales shares of light-duty vehicles were compared by running each model using the same inputs, where possible, for two scenarios. The five models compared — LVCFlex, MA3T, LAVE-Trans, ParaChoice, and ADOPT — have been used in support of the Energy Efficiency and Renewable Energy (EERE) Vehicle Technologies Office in analyses of future light-duty vehicle markets under different assumptions about future vehicle technologies and market conditions. The models give projections of sales shares by powertrain technology. Projections made using common, but not identical, inputs showed qualitative agreement, with the exception ofmore » ADOPT. ADOPT estimated somewhat lower advanced vehicle shares, mostly composed of hybrid electric vehicles. Other models projected large shares of multiple advanced vehicle powertrains. Projections of models differed in significant ways, including how different technologies penetrated cars and light trucks. Since the models are constructed differently and take different inputs, not all inputs were identical, but were the same or very similar where possible. Projections by all models were in close agreement only in the first few years. Although the projections from LVCFlex, MA3T, LAVE-Trans, and ParaChoice were in qualitative agreement, there were significant differences in sales shares given by the different models for individual powertrain types, particularly in later years (2030 and later). For example, projected sales shares of conventional spark-ignition vehicles in 2030 for a given scenario ranged from 35% to 74%. Reasons for such differences are discussed, recognizing that these models were not developed to give quantitatively accurate predictions of future sales shares, but to represent vehicles markets realistically and capture the connections between sales and important influences. Model features were also compared at a high level, and suggestions for further comparison of models are given to enable better understanding of how different features and algorithms used in these models may give different projections.« less

Effect of multimedia information sequencing on educational outcome in orthodontic training.

PubMed

Aly, Medhat; Willems, Guy; Van Den Noortgate, Wim; Elen, Jan

2012-08-01

The aim of this research was to compare the effectiveness of hierarchical sequencing (HS) versus elaboration sequencing (ES) models in improving educational outcome of clinical knowledge when using instructional multimedia programs in postgraduate orthodontic training. Twenty-four postgraduate and 24 undergraduate dental students participated in this study. The postgraduates were following an orthodontic speciality training programme. The undergraduates were fourth- and fifth-year dental students. Twelve instructional multimedia modules were developed, six logically sequenced (LS) discussing six different orthodontic topics. Another six modules on identical topics were sequenced according to one macro-sequencing (MS) model. The implemented MS model was either HS or ES. The only difference between LS and MS modules was the adopted sequencing model. All participants were assigned into consistent pairs of students and were randomly divided into a test and a control group. In each pair, one student studied the LS module (control group) while the other studied the MS version (test group). Pre- and post-evaluation tests of each pair of participants were performed to measure knowledge, understanding and application of each participant with regard to the discussed topic. A multilevel analysis was conducted to assess the estimated effect of the different sequencing models. The level of significance was set at 0.05. At baseline, no significant differences (P > 0.05) were found in pre-test scores between groups. The HS model showed a significant effect on the scores achieved (P = 0.05). The test group showed a significantly higher estimated probability of correct answers to the questions (P = 0.003) when applying the HS model. The HS model may improve educational outcome when using instructional multimedia programs in postgraduate orthodontic training.

Assessment of a novel biomechanical fracture model for distal radius fractures

PubMed Central

2012-01-01

Background Distal radius fractures (DRF) are one of the most common fractures and often need surgical treatment, which has been validated through biomechanical tests. Currently a number of different fracture models are used, none of which resemble the in vivo fracture location. The aim of the study was to develop a new standardized fracture model for DRF (AO-23.A3) and compare its biomechanical behavior to the current gold standard. Methods Variable angle locking volar plates (ADAPTIVE, Medartis) were mounted on 10 pairs of fresh-frozen radii. The osteotomy location was alternated within each pair (New: 10 mm wedge 8 mm / 12 mm proximal to the dorsal / volar apex of the articular surface; Gold standard: 10 mm wedge 20 mm proximal to the articular surface). Each specimen was tested in cyclic axial compression (increasing load by 100 N per cycle) until failure or −3 mm displacement. Parameters assessed were stiffness, displacement and dissipated work calculated for each cycle and ultimate load. Significance was tested using a linear mixed model and Wald test as well as t-tests. Results 7 female and 3 male pairs of radii aged 74 ± 9 years were tested. In most cases (7/10), the two groups showed similar mechanical behavior at low loads with increasing differences at increasing loads. Overall the novel fracture model showed a significant different biomechanical behavior than the gold standard model (p < 0,001). The average final loads resisted were significantly lower in the novel model (860 N ± 232 N vs. 1250 N ± 341 N; p = 0.001). Conclusion The novel biomechanical fracture model for DRF more closely mimics the in vivo fracture site and shows a significantly different biomechanical behavior with increasing loads when compared to the current gold standard. PMID:23244634

A Monte Carlo Uncertainty Analysis of Ozone Trend Predictions in a Two Dimensional Model. Revision

NASA Technical Reports Server (NTRS)

Considine, D. B.; Stolarski, R. S.; Hollandsworth, S. M.; Jackman, C. H.; Fleming, E. L.

1998-01-01

We use Monte Carlo analysis to estimate the uncertainty in predictions of total O3 trends between 1979 and 1995 made by the Goddard Space Flight Center (GSFC) two-dimensional (2D) model of stratospheric photochemistry and dynamics. The uncertainty is caused by gas-phase chemical reaction rates, photolysis coefficients, and heterogeneous reaction parameters which are model inputs. The uncertainty represents a lower bound to the total model uncertainty assuming the input parameter uncertainties are characterized correctly. Each of the Monte Carlo runs was initialized in 1970 and integrated for 26 model years through the end of 1995. This was repeated 419 times using input parameter sets generated by Latin Hypercube Sampling. The standard deviation (a) of the Monte Carlo ensemble of total 03 trend predictions is used to quantify the model uncertainty. The 34% difference between the model trend in globally and annually averaged total O3 using nominal inputs and atmospheric trends calculated from Nimbus 7 and Meteor 3 total ozone mapping spectrometer (TOMS) version 7 data is less than the 46% calculated 1 (sigma), model uncertainty, so there is no significant difference between the modeled and observed trends. In the northern hemisphere midlatitude spring the modeled and observed total 03 trends differ by more than 1(sigma) but less than 2(sigma), which we refer to as marginal significance. We perform a multiple linear regression analysis of the runs which suggests that only a few of the model reactions contribute significantly to the variance in the model predictions. The lack of significance in these comparisons suggests that they are of questionable use as guides for continuing model development. Large model/measurement differences which are many multiples of the input parameter uncertainty are seen in the meridional gradients of the trend and the peak-to-peak variations in the trends over an annual cycle. These discrepancies unambiguously indicate model formulation problems and provide a measure of model performance which can be used in attempts to improve such models.

The European Academy laparoscopic “Suturing Training and Testing’’ (SUTT) significantly improves surgeons’ performance

PubMed Central

Sleiman, Z.; Tanos, V.; Van Belle, Y.; Carvalho, J.L.; Campo, R.

2015-01-01

The efficiency of suturing training and testing (SUTT) model by laparoscopy was evaluated, measuring the suturingskill acquisition of trainee gynecologists at the beginning and at the end of a teaching course. During a workshop organized by the European Academy of Gynecological Surgery (EAGS), 25 participants with three different experience levels in laparoscopy (minor, intermediate and major) performed the 4 exercises of the SUTT model (Ex 1: both hands stitching and continuous suturing, Ex 2: right hand stitching and intracorporeal knotting, Ex 3: left hand stitching and intracorporeal knotting, Ex 4: dominant hand stitching, tissue approximation and intracorporeal knotting). The time needed to perform the exercises is recorded for each trainee and group and statistical analysis used to note the differences. Overall, all trainees achieved significant improvement in suturing time (p < 0.005) as measured before and after completion of the training. Similar significantly improved suturing time differences (p < 0.005) were noted among the groups of trainees with different laparoscopic experience. In conclusion a short well-guided training course, using the SUTT model, improves significantly surgeon’s laparoscopic suturing ability, independently of the level of experience in laparoscopic surgery. Key words: Endoscopy, laparoscopic suturing, psychomotor skills, surgery, teaching, training suturing model. PMID:26977264

Parenting stress and depressive symptoms in postpartum mothers: Bidirectional or unidirectional effects?

PubMed Central

Thomason, Elizabeth; Volling, Brenda L.; Flynn, Heather A.; McDonough, Susan C.; Marcus, Sheila M.; Lopez, Juan F.; Vazquez, Delia M.

2015-01-01

Despite the consistent link between parenting stress and postpartum depressive symptoms, few studies have explored the relationships longitudinally. The purpose of this study was to test bidirectional and unidirectional models of depressive symptoms and parenting stress. Uniquely, three specific domains of parenting stress were examined: parental distress, difficult child stress, and parent–child dysfunctional interaction (PCDI). One hundred and five women completed the Beck Depression Inventory and the Parenting Stress Index–Short Form at 3, 7, and 14 months after giving birth. Structural equation modeling revealed that total parenting stress predicted later depressive symptoms, however, there were different patterns between postpartum depressive symptoms and different types of parenting stress. A unidirectional model of parental distress predicting depressive symptoms best fit the data, with significant stability paths but non-significant cross-lagged paths. A unidirectional model of depressive symptoms predicted significant later difficult child stress. No model fit well with PCDI. Future research should continue to explore the specific nature of the associations of postpartum depression and different types of parenting stress on infant development and the infant–mother relationship. PMID:24956500

Predicting Operator Execution Times Using CogTool

NASA Technical Reports Server (NTRS)

Santiago-Espada, Yamira; Latorella, Kara A.

2013-01-01

Researchers and developers of NextGen systems can use predictive human performance modeling tools as an initial approach to obtain skilled user performance times analytically, before system testing with users. This paper describes the CogTool models for a two pilot crew executing two different types of a datalink clearance acceptance tasks, and on two different simulation platforms. The CogTool time estimates for accepting and executing Required Time of Arrival and Interval Management clearances were compared to empirical data observed in video tapes and registered in simulation files. Results indicate no statistically significant difference between empirical data and the CogTool predictions. A population comparison test found no significant differences between the CogTool estimates and the empirical execution times for any of the four test conditions. We discuss modeling caveats and considerations for applying CogTool to crew performance modeling in advanced cockpit environments.

Ensenanzas en un gimnasio: an investigation of modeling and verbal rehearsal on the motor performance of Hispanic limited English proficient children.

PubMed

Meaney, K S; Edwards, R

1996-03-01

This study investigated the effects of modeling and verbal rehearsal on the motor performance of English-speaking and limited English proficient (LEP) children. Children (N = 64) in 4th-grade classes were randomly assigned to conditions in a 2 x 2 x 2 x 2 (Gender x Primary Language x Model Type x Rehearsal) factorial design. Boys and girls whose primary language was English or Spanish were assigned to either a verbal model or no-model condition as well as to a verbal rehearsal or no-rehearsal condition of the motor skills required to be performed. Analysis of variance revealed a significant Model Type x Primary Language interaction as well as a significant Rehearsal x Primary Language interaction. Follow-up analyses revealed that English-speaking children provided with a verbal rehearsal strategy recalled significantly more skills than English-speaking children in the no-rehearsal condition; for LEP children, there were no differences due to rehearsal. Moreover, LEP children presented with a verbal model recalled significantly more skills than LEP children in the no-model condition; for English-speaking children, there were no differences attributed to model type. These results indicate that effective modeling conditions that are provided with verbal cues in English are related to children's primary language.

Impact of Gender on Pharmocokinetics of Intranasal Scopolamine

NASA Technical Reports Server (NTRS)

Putcha, L.; Lei, Wu.; S-L Chow, Diana

2013-01-01

Introduction: An intranasal gel dosage formulation of scopolamine (INSCOP) was developed for the treatment of Space Motion Sickness (SMS), which is commonly experienced by astronauts during space missions. The bioavailability and pharmacokinetics (PK) were evaluated under IND guidelines. Since information is lacking on the effect of gender on the PK of Scopolamine, we examined gender differences in PK parameters of INSCOP at three dose levels of 0.1, 0.2 and 0.4 mg. Methods: Plasma scopolamine concentrations as a function of time data were collected from twelve normal healthy human subjects (6 male/6 female) who participated in a fully randomized double blind crossover study. The PK parameters were derived using WinNonlin. Covariate analysis of PK profiles was performed using NONMEN and statistically compared using a likelihood ratio test on the difference of objective function value (OFV). Statistical significance for covariate analysis was set at P<0.05(?OFV=3.84). Results: No significant difference in PK parameters between male and female subjects was observed with 0.1 and 0.2 mg doses. However, CL and Vd were significantly different between male and female subjects at the 0.4 mg dose. Results from population covariate modeling analysis indicate that a onecompartment PK model with first-order elimination rate offers best fit for describing INSCOP concentration-time profiles. The inclusion of sex as a covariate enhanced the model fitting (?OFV=-4.1) owing to the genderdependent CL and Vd differences after the 0.4 mg dose. Conclusion: Statistical modeling of scopolamine concentration-time data suggests gender-dependent pharmacokinetics of scopolamine at the high dose level of 0.4 mg. Clearance of the parent compound was significantly faster and the volume of distribution was significantly higher in males than in females, As a result, including gender as a covariate to the pharmacokinetic model of scopolamine offers the best fit for PK modeling of the drug at dose of 0.4 mg or higher.

Sex-specific developmental models for Creophilus maxillosus (L.) (Coleoptera: Staphylinidae): searching for larger accuracy of insect age estimates.

PubMed

Frątczak-Łagiewska, Katarzyna; Matuszewski, Szymon

2018-05-01

Differences in size between males and females, called the sexual size dimorphism, are common in insects. These differences may be followed by differences in the duration of development. Accordingly, it is believed that insect sex may be used to increase the accuracy of insect age estimates in forensic entomology. Here, the sex-specific differences in the development of Creophilus maxillosus were studied at seven constant temperatures. We have also created separate developmental models for males and females of C. maxillosus and tested them in a validation study to answer a question whether sex-specific developmental models improve the accuracy of insect age estimates. Results demonstrate that males of C. maxillosus developed significantly longer than females. The sex-specific and general models for the total immature development had the same optimal temperature range and similar developmental threshold but different thermal constant K, which was the largest in the case of the male-specific model and the smallest in the case of the female-specific model. Despite these differences, validation study revealed just minimal and statistically insignificant differences in the accuracy of age estimates using sex-specific and general thermal summation models. This finding indicates that in spite of statistically significant differences in the duration of immature development between females and males of C. maxillosus, there is no increase in the accuracy of insect age estimates while using the sex-specific thermal summation models compared to the general model. Accordingly, this study does not support the use of sex-specific developmental data for the estimation of insect age in forensic entomology.

Vibration acceleration promotes bone formation in rodent models

PubMed Central

Uchida, Ryohei; Nakata, Ken; Kawano, Fuminori; Yonetani, Yasukazu; Ogasawara, Issei; Nakai, Naoya; Mae, Tatsuo; Matsuo, Tomohiko; Tachibana, Yuta; Yokoi, Hiroyuki; Yoshikawa, Hideki

2017-01-01

All living tissues and cells on Earth are subject to gravitational acceleration, but no reports have verified whether acceleration mode influences bone formation and healing. Therefore, this study was to compare the effects of two acceleration modes, vibration and constant (centrifugal) accelerations, on bone formation and healing in the trunk using BMP 2-induced ectopic bone formation (EBF) mouse model and a rib fracture healing (RFH) rat model. Additionally, we tried to verify the difference in mechanism of effect on bone formation by accelerations between these two models. Three groups (low- and high-magnitude vibration and control-VA groups) were evaluated in the vibration acceleration study, and two groups (centrifuge acceleration and control-CA groups) were used in the constant acceleration study. In each model, the intervention was applied for ten minutes per day from three days after surgery for eleven days (EBF model) or nine days (RFH model). All animals were sacrificed the day after the intervention ended. In the EBF model, ectopic bone was evaluated by macroscopic and histological observations, wet weight, radiography and microfocus computed tomography (micro-CT). In the RFH model, whole fracture-repaired ribs were excised with removal of soft tissue, and evaluated radiologically and histologically. Ectopic bones in the low-magnitude group (EBF model) had significantly greater wet weight and were significantly larger (macroscopically and radiographically) than those in the other two groups, whereas the size and wet weight of ectopic bones in the centrifuge acceleration group showed no significant difference compared those in control-CA group. All ectopic bones showed calcified trabeculae and maturated bone marrow. Micro-CT showed that bone volume (BV) in the low-magnitude group of EBF model was significantly higher than those in the other two groups (3.1±1.2mm3 v.s. 1.8±1.2mm3 in high-magnitude group and 1.3±0.9mm3 in control-VA group), but BV in the centrifuge acceleration group had no significant difference compared those in control-CA group. Union rate and BV in the low-magnitude group of RFH model were also significantly higher than those in the other groups (Union rate: 60% v.s. 0% in the high-magnitude group and 10% in the control-VA group, BV: 0.69±0.30mm3 v.s. 0.15±0.09mm3 in high-magnitude group and 0.22±0.17mm3 in control-VA group). BV/TV in the low-magnitude group of RFH model was significantly higher than that in control-VA group (59.4±14.9% v.s. 35.8±13.5%). On the other hand, radiographic union rate (10% in centrifuge acceleration group v.s. 20% in control-CA group) and micro-CT parameters in RFH model were not significantly different between two groups in the constant acceleration studies. Radiographic images of non-union rib fractures showed cartilage at the fracture site and poor new bone formation, whereas union samples showed only new bone. In conclusion, low-magnitude vibration acceleration promoted bone formation at the trunk in both BMP-induced ectopic bone formation and rib fracture healing models. However, the micro-CT parameters were not similar between two models, which suggested that there might be difference in the mechanism of effect by vibration between two models. PMID:28264058

Vibration acceleration promotes bone formation in rodent models.

PubMed

Uchida, Ryohei; Nakata, Ken; Kawano, Fuminori; Yonetani, Yasukazu; Ogasawara, Issei; Nakai, Naoya; Mae, Tatsuo; Matsuo, Tomohiko; Tachibana, Yuta; Yokoi, Hiroyuki; Yoshikawa, Hideki

2017-01-01

All living tissues and cells on Earth are subject to gravitational acceleration, but no reports have verified whether acceleration mode influences bone formation and healing. Therefore, this study was to compare the effects of two acceleration modes, vibration and constant (centrifugal) accelerations, on bone formation and healing in the trunk using BMP 2-induced ectopic bone formation (EBF) mouse model and a rib fracture healing (RFH) rat model. Additionally, we tried to verify the difference in mechanism of effect on bone formation by accelerations between these two models. Three groups (low- and high-magnitude vibration and control-VA groups) were evaluated in the vibration acceleration study, and two groups (centrifuge acceleration and control-CA groups) were used in the constant acceleration study. In each model, the intervention was applied for ten minutes per day from three days after surgery for eleven days (EBF model) or nine days (RFH model). All animals were sacrificed the day after the intervention ended. In the EBF model, ectopic bone was evaluated by macroscopic and histological observations, wet weight, radiography and microfocus computed tomography (micro-CT). In the RFH model, whole fracture-repaired ribs were excised with removal of soft tissue, and evaluated radiologically and histologically. Ectopic bones in the low-magnitude group (EBF model) had significantly greater wet weight and were significantly larger (macroscopically and radiographically) than those in the other two groups, whereas the size and wet weight of ectopic bones in the centrifuge acceleration group showed no significant difference compared those in control-CA group. All ectopic bones showed calcified trabeculae and maturated bone marrow. Micro-CT showed that bone volume (BV) in the low-magnitude group of EBF model was significantly higher than those in the other two groups (3.1±1.2mm3 v.s. 1.8±1.2mm3 in high-magnitude group and 1.3±0.9mm3 in control-VA group), but BV in the centrifuge acceleration group had no significant difference compared those in control-CA group. Union rate and BV in the low-magnitude group of RFH model were also significantly higher than those in the other groups (Union rate: 60% v.s. 0% in the high-magnitude group and 10% in the control-VA group, BV: 0.69±0.30mm3 v.s. 0.15±0.09mm3 in high-magnitude group and 0.22±0.17mm3 in control-VA group). BV/TV in the low-magnitude group of RFH model was significantly higher than that in control-VA group (59.4±14.9% v.s. 35.8±13.5%). On the other hand, radiographic union rate (10% in centrifuge acceleration group v.s. 20% in control-CA group) and micro-CT parameters in RFH model were not significantly different between two groups in the constant acceleration studies. Radiographic images of non-union rib fractures showed cartilage at the fracture site and poor new bone formation, whereas union samples showed only new bone. In conclusion, low-magnitude vibration acceleration promoted bone formation at the trunk in both BMP-induced ectopic bone formation and rib fracture healing models. However, the micro-CT parameters were not similar between two models, which suggested that there might be difference in the mechanism of effect by vibration between two models.

Effect of nano-silver hydrogel coating film on deep partial thickness scald model of rabbit.

PubMed

Xi, Peng; Li, Yan; Ge, Xiaojin; Liu, Dandan; Miao, Mingsan

2018-05-01

Observing the effect of nano-silver hydrogel coating film on deep partial thickness scald model of rabbit. We prepared boiling water scalded rabbits with deep II degree scald models and applied high, medium and low doses of nano-silver hydrogel coating film for different time and area. Then we compared the difference of burned paper weight before administration and after administration model burns, burn local skin irritation points infection, skin crusting and scabs from the time, and the impact of local skin tissue morphology. Rabbits deep II degree burn model successful modeling; on day 12, 18, high, medium and low doses of nano-silver hydrogel coating film significantly reduced skin irritation of rabbits infected with the integral value ( P  < 0.01, P  < 0.05); high, medium and low doses of nano-silver hydrogel coating film group significantly decreased skin irritation, infection integral value ( P  < 0.01, P  < 0.05); high, medium and low doses of nano-silver hydrogel coating film significantly reduced film rabbits' scalded skin crusting time ( P  < 0.01), significantly shortened the rabbit skin burns from the scab time ( P  < 0.01), and significantly improved the treatment of skin diseases in rabbits scald model change ( P  < 0.01, P  < 0.05). The nano-silver hydrogel coating film on the deep partial thickness burns has a significant therapeutic effect; external use has a significant role in wound healing.

On central-difference and upwind schemes

NASA Technical Reports Server (NTRS)

Swanson, R. C.; Turkel, Eli

1990-01-01

A class of numerical dissipation models for central-difference schemes constructed with second- and fourth-difference terms is considered. The notion of matrix dissipation associated with upwind schemes is used to establish improved shock capturing capability for these models. In addition, conditions are given that guarantee that such dissipation models produce a Total Variation Diminishing (TVD) scheme. Appropriate switches for this type of model to ensure satisfaction of the TVD property are presented. Significant improvements in the accuracy of a central-difference scheme are demonstrated by computing both inviscid and viscous transonic airfoil flows.

Analysis and comparison of the biomechanical properties of univalved and bivalved cast models.

PubMed

Crickard, Colin V; Riccio, Anthony I; Carney, Joseph R; Anderson, Terrence D

2011-01-01

Fiberglass casts are frequently valved to relieve the pressure associated with upper extremity swelling after a surgical procedure or when applied after reduction of a displaced fracture in a child. Although different opinions exist regarding the valving of casts, no research to date has explored the biomechanical effects of this commonly used technique. As cast integrity is essential for the maintenance of fracture reduction, it is important to understand whether casts are structurally compromised after valving. Understanding the effects of valving on cast integrity may help guide clinicians in the technique of valving while minimizing the potential for a loss of fracture reduction. Thirty standardized cylindrical fiberglass cast models were created. Ten models were left intact, 10 were univalved, and 10 were bivalved. All the models were mechanically tested by a 3-point bending apparatus secured to a biaxial materials testing system. Load to failure and bending stiffness were recorded for each sample. Differences in load of failure and bending stiffness were compared among the groups. Unvalved cast models had the highest failure load and bending stiffness, whereas bivalved casts showed the lowest value for both failure load and bending stiffness. Univalved casts had a failure load measured to be between those of unvalved and bivalved cast models. Analysis of variance showed significance when failure load and bending stiffness data among all the groups were compared. A post hoc Bonferroni statistical analysis showed significance in bending stiffness between intact and bivalved models (P < 0.01), intact and univalved models (P < 0.01), but no significant difference in bending stiffness between univalved and bivalved models (P > 0.01). Differences in measured failure load values were found to be statistically significant among all cast models (P < 0.01). Valving significantly decreases the bending stiffness and load to failure of fiberglass casts. Univalved casts have a higher load to failure than bivalved casts. Valving adversely alters the structural integrity of fiberglass casts. This may impair a cast's ability to effectively immobilize an extremity or maintain a fracture reduction.

Comparison of two different artificial neural networks for prostate biopsy indication in two different patient populations.

PubMed

Stephan, Carsten; Xu, Chuanliang; Finne, Patrik; Cammann, Henning; Meyer, Hellmuth-Alexander; Lein, Michael; Jung, Klaus; Stenman, Ulf-Hakan

2007-09-01

Different artificial neural networks (ANNs) using total prostate-specific antigen (PSA) and percentage of free PSA (%fPSA) have been introduced to enhance the specificity of prostate cancer detection. The applicability of independently trained ANN and logistic regression (LR) models to different populations regarding the composition (screening versus referred) and different PSA assays has not yet been tested. Two ANN and LR models using PSA (range 4 to 10 ng/mL), %fPSA, prostate volume, digital rectal examination findings, and patient age were tested. A multilayer perceptron network (MLP) was trained on 656 screening participants (Prostatus PSA assay) and another ANN (Immulite-based ANN [iANN]) was constructed on 606 multicentric urologically referred men. These and other assay-adapted ANN models, including one new iANN-based ANN, were used. The areas under the curve for the iANN (0.736) and MLP (0.745) were equal but showed no differences to %fPSA (0.725) in the Finnish group. Only the new iANN-based ANN reached a significant larger area under the curve (0.77). At 95% sensitivity, the specificities of MLP (33%) and the new iANN-based ANN (34%) were significantly better than the iANN (23%) and %fPSA (19%). Reverse methodology using the MLP model on the referred patients revealed, in contrast, a significant improvement in the areas under the curve for iANN and MLP (each 0.83) compared with %fPSA (0.70). At 90% and 95% sensitivity, the specificities of all LR and ANN models were significantly greater than those for %fPSA. The ANNs based on different PSA assays and populations were mostly comparable, but the clearly different patient composition also allowed with assay adaptation no unbiased ANN application to the other cohort. Thus, the use of ANNs in other populations than originally built is possible, but has limitations.

Doctor Discontent

PubMed Central

Murray, Alison; Montgomery, Jana E; Chang, Hong; Rogers, William H; Inui, Thomas; Safran, Dana Gelb

2001-01-01

OBJECTIVE To examine the differences in physician satisfaction associated with open- versus closed-model practice settings and to evaluate changes in physician satisfaction between 1986 and 1997. Open-model practices refer to those in which physicians accept patients from multiple health plans and insurers (i.e., do not have an exclusive arrangement with any single health plan). Closed-model practices refer to those wherein physicians have an exclusive relationship with a single health plan (i.e., staff- or group-model HMO). DESIGN Two cross-sectional surveys of physicians; one conducted in 1986 (Medical Outcomes Study) and one conducted in 1997 (Study of Primary Care Performance in Massachusetts). SETTING Primary care practices in Massachusetts. PARTICIPANTS General internists and family practitioners in Massachusetts. MEASUREMENTS Seven measures of physician satisfaction, including satisfaction with quality of care, the potential to achieve professional goals, time spent with individual patients, total earnings from practice, degree of personal autonomy, leisure time, and incentives for high quality. RESULTS Physicians in open- versus closed-model practices differed significantly in several aspects of their professional satisfaction. In 1997, open-model physicians were less satisfied than closed-model physicians with their total earnings, leisure time, and incentives for high quality. Open-model physicians reported significantly more difficulty with authorization procedures and reported more denials for care. Overall, physicians in 1997 were less satisfied in every aspect of their professional life than 1986 physicians. Differences were significant in three areas: time spent with individual patients, autonomy, and leisure time (P ≤ .05). Among open-model physicians, satisfaction with autonomy and time with individual patients were significantly lower in 1997 than 1986 (P ≤ .01). Among closed-model physicians, satisfaction with total earnings and with potential to achieve professional goals were significantly lower in 1997 than in 1986 (P ≤ .01). CONCLUSIONS This study finds that the state of physician satisfaction in Massachusetts is extremely low, with the majority of physicians dissatisfied with the amount of time they have with individual patients, their leisure time, and their incentives for high quality. Satisfaction with most areas of practice declined significantly between 1986 and 1997. Open-model physicians were less satisfied than closed-model physicians in most aspects of practices.

Laparoscopic surgical box model training for surgical trainees with no prior laparoscopic experience.

PubMed

Nagendran, Myura; Toon, Clare D; Davidson, Brian R; Gurusamy, Kurinchi Selvan

2014-01-17

Surgical training has traditionally been one of apprenticeship, where the surgical trainee learns to perform surgery under the supervision of a trained surgeon. This is time consuming, costly, and of variable effectiveness. Training using a box model physical simulator - either a video box or a mirrored box - is an option to supplement standard training. However, the impact of this modality on trainees with no prior laparoscopic experience is unknown. To compare the benefits and harms of box model training versus no training, another box model, animal model, or cadaveric model training for surgical trainees with no prior laparoscopic experience. We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, and Science Citation Index Expanded to May 2013. We included all randomised clinical trials comparing box model trainers versus no training in surgical trainees with no prior laparoscopic experience. We also included trials comparing different methods of box model training. Two authors independently identified trials and collected data. We analysed the data with both the fixed-effect and the random-effects models using Review Manager for analysis. For each outcome, we calculated the standardised mean difference (SMD) with 95% confidence intervals (CI) based on intention-to-treat analysis whenever possible. Twenty-five trials contributed data to the quantitative synthesis in this review. All but one trial were at high risk of bias. Overall, 16 trials (464 participants) provided data for meta-analysis of box training (248 participants) versus no supplementary training (216 participants). All the 16 trials in this comparison used video trainers. Overall, 14 trials (382 participants) provided data for quantitative comparison of different methods of box training. There were no trials comparing box model training versus animal model or cadaveric model training. Box model training versus no training: The meta-analysis showed that the time taken for task completion was significantly shorter in the box trainer group than the control group (8 trials; 249 participants; SMD -0.48 seconds; 95% CI -0.74 to -0.22). Compared with the control group, the box trainer group also had lower error score (3 trials; 69 participants; SMD -0.69; 95% CI -1.21 to -0.17), better accuracy score (3 trials; 73 participants; SMD 0.67; 95% CI 0.18 to 1.17), and better composite performance scores (SMD 0.65; 95% CI 0.42 to 0.88). Three trials reported movement distance but could not be meta-analysed as they were not in a format for meta-analysis. There was significantly lower movement distance in the box model training compared with no training in one trial, and there were no significant differences in the movement distance between the two groups in the other two trials. None of the remaining secondary outcomes such as mortality and morbidity were reported in the trials when animal models were used for assessment of training, error in movements, and trainee satisfaction. Different methods of box training: One trial (36 participants) found significantly shorter time taken to complete the task when box training was performed using a simple cardboard box trainer compared with the standard pelvic trainer (SMD -3.79 seconds; 95% CI -4.92 to -2.65). There was no significant difference in the time taken to complete the task in the remaining three comparisons (reverse alignment versus forward alignment box training; box trainer suturing versus box trainer drills; and single incision versus multiport box model training). There were no significant differences in the error score between the two groups in any of the comparisons (box trainer suturing versus box trainer drills; single incision versus multiport box model training; Z-maze box training versus U-maze box training). The only trial that reported accuracy score found significantly higher accuracy score with Z-maze box training than U-maze box training (1 trial; 16 participants; SMD 1.55; 95% CI 0.39 to 2.71). One trial (36 participants) found significantly higher composite score with simple cardboard box trainer compared with conventional pelvic trainer (SMD 0.87; 95% CI 0.19 to 1.56). Another trial (22 participants) found significantly higher composite score with reverse alignment compared with forward alignment box training (SMD 1.82; 95% CI 0.79 to 2.84). There were no significant differences in the composite score between the intervention and control groups in any of the remaining comparisons. None of the secondary outcomes were adequately reported in the trials. The results of this review are threatened by both risks of systematic errors (bias) and risks of random errors (play of chance). Laparoscopic box model training appears to improve technical skills compared with no training in trainees with no previous laparoscopic experience. The impacts of this decreased time on patients and healthcare funders in terms of improved outcomes or decreased costs are unknown. There appears to be no significant differences in the improvement of technical skills between different methods of box model training. Further well-designed trials of low risk of bias and random errors are necessary. Such trials should assess the impacts of box model training on surgical skills in both the short and long term, as well as clinical outcomes when the trainee becomes competent to operate on patients.

Soil depth influence on Amazonian ecophysiology

NASA Astrophysics Data System (ADS)

Fagerstrom, I.; Baker, I. T.; Gallup, S.; Denning, A. S.

2017-12-01

Models of land-atmosphere interaction are important for simulating present day weather and critical for predictions of future climate. Land-atmosphere interaction models have become increasingly complex in the last 30 years, leading to the need for further studies examining their intricacies and improvement. This research focuses on the effect of variable soil depth on Amazonian Gross Primary Production (GPP), respiration, and their combination into overall carbon flux. We evaluate a control, which has a universal soil depth of 10 meters, with two experiments of variable soil depths. To conduct this study we ran the 3 models for the period 2000-2012, evaluating similarities and differences between them. We focus on the Amazon rain forest, and compare differences in components of carbon flux. Not surprisingly, we find that the main differences between the models arises in regions where the soil depth is dissimilar between models. However, we did not observe significant differences in GPP between known drought, wet, and average years; interannual variability in carbon dynamics was less than anticipated. We also anticipated that differences between models would be most significant during the dry season, but found discrepancies that persisted through the entire annual cycle.

Solutions for Determining the Significance Region Using the Johnson-Neyman Type Procedure in Generalized Linear (Mixed) Models

ERIC Educational Resources Information Center

Lazar, Ann A.; Zerbe, Gary O.

2011-01-01

Researchers often compare the relationship between an outcome and covariate for two or more groups by evaluating whether the fitted regression curves differ significantly. When they do, researchers need to determine the "significance region," or the values of the covariate where the curves significantly differ. In analysis of covariance (ANCOVA),…

Heavy metals in laughing gulls: Gender, age and tissue differences

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

Gochfeld, M.; Belant, J.L.; Shukla, T.

1996-12-01

The authors examined concentrations of lead, cadmium, mercury, manganese, selenium, and chromium in feathers, liver, kidney, heart, and muscle of known-aged laughing gulls (Larus atricilla) that hatched in Barnegat Bay, New Jersey and were collected at John F. Kennedy International Airport, New York 1 to 7 years later. Concentrations differed significantly among tissues, and tissue entered all the regression models explaining the greatest variation in metal levels. Age of bird contributed significantly to the models for lead, cadmium, selenium, and chromium. Although there were significant gender differences in all body measurements except wing length, there were few differences in metalmore » levels. Males had significantly higher lead levels in feathers, and females had significantly higher selenium levels in heart and muscle tissue. For lead, 3-year olds had the highest levels in the heart, liver, and kidney, and levels were lower thereafter. Mercury levels in feathers and heart decreased significantly with age. Cadmium levels increased significantly with age for feathers, heart, liver, and muscle, although there was a slight decrease in the 7-year olds. Selenium levels decreased significantly with age for all tissues. Chromium levels increased with age for liver and heart.« less

On the influence of simulated SST warming on rainfall projections in the Indo-Pacific domain: an AGCM study

NASA Astrophysics Data System (ADS)

Zhang, Huqiang; Zhao, Y.; Moise, A.; Ye, H.; Colman, R.; Roff, G.; Zhao, M.

2018-02-01

Significant uncertainty exists in regional climate change projections, particularly for rainfall and other hydro-climate variables. In this study, we conduct a series of Atmospheric General Circulation Model (AGCM) experiments with different future sea surface temperature (SST) warming simulated by a range of coupled climate models. They allow us to assess the extent to which uncertainty from current coupled climate model rainfall projections can be attributed to their simulated SST warming. Nine CMIP5 model-simulated global SST warming anomalies have been super-imposed onto the current SSTs simulated by the Australian climate model ACCESS1.3. The ACCESS1.3 SST-forced experiments closely reproduce rainfall means and interannual variations as in its own fully coupled experiments. Although different global SST warming intensities explain well the inter-model difference in global mean precipitation changes, at regional scales the SST influence vary significantly. SST warming explains about 20-25% of the patterns of precipitation changes in each of the four/five models in its rainfall projections over the oceans in the Indo-Pacific domain, but there are also a couple of models in which different SST warming explains little of their precipitation pattern changes. The influence is weaker again for rainfall changes over land. Roughly similar levels of contribution can be attributed to different atmospheric responses to SST warming in these models. The weak SST influence in our study could be due to the experimental setup applied: superimposing different SST warming anomalies onto the same SSTs simulated for current climate by ACCESS1.3 rather than directly using model-simulated past and future SSTs. Similar modelling and analysis from other modelling groups with more carefully designed experiments are needed to tease out uncertainties caused by different SST warming patterns, different SST mean biases and different model physical/dynamical responses to the same underlying SST forcing.

A Quantitative Review and Meta-Models of the Variability and Factors Affecting Oral Drug Absorption-Part I: Gastrointestinal pH.

PubMed

Abuhelwa, Ahmad Y; Foster, David J R; Upton, Richard N

2016-09-01

This study aimed to conduct a quantitative meta-analysis for the values of, and variability in, gastrointestinal (GI) pH in the different GI segments; characterize the effect of food on the values and variability in these parameters; and present quantitative meta-models of distributions of GI pH to help inform models of oral drug absorption. The literature was systemically reviewed for the values of, and the variability in, GI pH under fed and fasted conditions. The GI tract was categorized into the following 10 distinct regions: stomach (proximal, mid-distal), duodenum (proximal, mid-distal), jejunum and ileum (proximal, mid, and distal small intestine), and colon (ascending, transverse, and descending colon). Meta-analysis used the "metafor" package of the R language. The time course of postprandial stomach pH was modeled using NONMEM. Food significantly influenced the estimated meta-mean stomach and duodenal pH but had no significant influence on small intestinal and colonic pH. The time course of postprandial pH was described using an exponential model. Increased meal caloric content increased the extent and duration of postprandial gastric pH buffering. The different parts of the small intestine had significantly different pH. Colonic pH was significantly different for descending but not for ascending and transverse colon. Knowledge of GI pH is important for the formulation design of the pH-dependent dosage forms and in understanding the dissolution and absorption of orally administered drugs. The meta-models of GI pH may also be used as part of semi-physiological pharmacokinetic models to characterize the effect of GI pH on the in vivo drug release and pharmacokinetics.

Agreement in the determination of preformed wire shape templates on plaster models and customized digital arch form diagrams on digital models.

PubMed

Camardella, Leonardo Tavares; Sá, Maiara da Silva Bezerra; Guimarães, Luciana Campos; Vilella, Beatriz de Souza; Vilella, Oswaldo de Vasconcellos

2018-03-01

The aim of this study was to verify the accuracy of preformed wire shape templates on plaster models and those of customized digital arch form diagrams on digital models. Twenty pairs of dental plaster models were randomly selected from the archives of the Department of Orthodontics of Federal Fluminense University, Niterói, Rio de Janeiro, Brazil. All plaster model samples were scanned in a plaster model scanner to create the respective digital models. Three examiners defined the arch form on the mandibular arch of these models by selecting the ideal preformed wire shape template on each plaster model or by making a customized digital arch form on the digital models using a digital arch form customization tool. These 2 arch forms were superimposed by the best-fit method. The greatest differences in the 6 regions on the superimposed arches were evaluated. Each examiner presented a descriptive analysis with the means, standard deviation, and minimum and maximum intervals of the differences on the superimpositions. Intraclass correlation coefficient and paired t tests were used to evaluate the accuracy of the superimpositions. Among the 6 regions analyzed in the superimpositions, the largest differences in the anterior and premolar regions were considered clinically insignificant, whereas the largest differences in the right molar region, especially the second molar area, were considered clinically significant by all 3 examiners. The intraclass correlation coefficients showed a weak correlation in the premolar region and moderate correlations in the anterior and molar regions. The paired t test showed statistically significant differences in the left anterior and premolar regions. The superimpositions between the arch forms on plaster and digital models were considered accurate, and the differences were not clinically significant, with the exception of the second molar area. Despite the favorable results, the requirement of correcting some software problems may hamper the transition from plaster to digital models. Copyright © 2017 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

No association of single nucleotide polymorphisms involved in GHRL and GHSR with cancer risk: a meta-analysis.

PubMed

Zhu, Shengjie; Shao, Bin; Hao, Yaoyao; Li, Zongxian; Liu, Houqiang; Li, Hong; Wang, Ming; Wang, Kai

2015-01-01

Ghrelin was associated with several of cancers. The conflict results of SNPs with GHRL and GHSR gene were demonstrated in different studies. Thus, this meta-analysis is to evaluate the associations. Systematic literature search was done on PubMed database up to October 2013. We used odds ratios (ORs) with 95% confidence intervals (CIs) to assess the strength of the association by a fixed-effect model and a random-effect model. A total of 7 studies, which included 3 studies for breast cancer, 2 for colorectal cancer, 1 for hepatocellular carcinoma, 1 for esophageal cancer and 1 for Non-Hodgkin lymphoma. When analyzed all the GHRL SNPs with all kinds of cancers, there was significantly difference with cancer patients compared with controls (Recessive model: OR 0.938, 95% CI 0.890-0.989, p=0.017), while no significant difference was existed in the additive model (OR 0.9903, 95% CI 0.957-1.024, p=0.558) and dominant model (OR 1.014, 95% CI 0.970-1.061, p=0.536). When analyzed all the GHSR SNPs with all kinds of cancers, no significant difference was observed. Our results suggest that the SNP with GHRL and GHSR might be weaker association with cancer risk, especially with breast cancer risk.

More Realistic Face Model Surface Improves Relevance of Pediatric In-Vitro Aerosol Studies.

PubMed

Amirav, Israel; Halamish, Asaf; Gorenberg, Miguel; Omar, Hamza; Newhouse, Michael T

2015-01-01

Various hard face models are commonly used to evaluate the efficiency of aerosol face masks. Softer more realistic "face" surface materials, like skin, deform upon mask application and should provide more relevant in-vitro tests. Studies that simultaneously take into consideration many of the factors characteristic of the in vivo face are lacking. These include airways, various application forces, comparison of various devices, comparison with a hard-surface model and use of a more representative model face based on large numbers of actual faces. To compare mask to "face" seal and aerosol delivery of two pediatric masks using a soft vs. a hard, appropriately representative, pediatric face model under various applied forces. Two identical face models and upper airways replicas were constructed, the only difference being the suppleness and compressibility of the surface layer of the "face." Integrity of the seal and aerosol delivery of two different masks [AeroChamber (AC) and SootherMask (SM)] were compared using a breath simulator, filter collection and realistic applied forces. The soft "face" significantly increased the delivery efficiency and the sealing characteristics of both masks. Aerosol delivery with the soft "face" was significantly greater for the SM compared to the AC (p< 0.01). No statistically significant difference between the two masks was observed with the hard "face." The material and pliability of the model "face" surface has a significant influence on both the seal and delivery efficiency of face masks. This finding should be taken into account during in-vitro aerosol studies.

An application of seasonal ARIMA models on group commodities to forecast Philippine merchandise exports performance

NASA Astrophysics Data System (ADS)

Natividad, Gina May R.; Cawiding, Olive R.; Addawe, Rizavel C.

2017-11-01

The increase in the merchandise exports of the country offers information about the Philippines' trading role within the global economy. Merchandise exports statistics are used to monitor the country's overall production that is consumed overseas. This paper investigates the comparison between two models obtained by a) clustering the commodity groups into two based on its proportional contribution to the total exports, and b) treating only the total exports. Different seasonal autoregressive integrated moving average (SARIMA) models were then developed for the clustered commodities and for the total exports based on the monthly merchandise exports of the Philippines from 2011 to 2016. The data set used in this study was retrieved from the Philippine Statistics Authority (PSA) which is the central statistical authority in the country responsible for primary data collection. A test for significance of the difference between means at 0.05 level of significance was then performed on the forecasts produced. The result indicates that there is a significant difference between the mean of the forecasts of the two models. Moreover, upon a comparison of the root mean square error (RMSE) and mean absolute error (MAE) of the models, it was found that the models used for the clustered groups outperform the model for the total exports.

[Study on the effect of different impression methods on the marginal fit of all-ceramic crowns].

PubMed

Zhan, Lilin; Zeng, Liwei; Chen, Ping; Liao, Lan; Li, Shiyue; Liu, Renying

2015-08-01

To investigate the effect of three different impression methods on the marginal fit of all-ceramic crowns. The three methods include scanning silicone rubber impression, cast models, and direct optical impression. The polymethyl methacrylate (PMMA) material of a mandibular first molar in standard model was prepared with 16 models duplicated. The all-ceramic crowns were prepared using three different impression methods. Accurate impressions were made using silicone rubber, and the cast models were obtained. The PMMA models, silicone rubber impressions, and cast models were scanned, and digital models of three groups were obtained to produce 48 zirconia all-ceramic crowns with computer aided design/computer aided manufacture. The marginal fit of these groups was measured by silicone rubber gap impression. Statistical analysis was performed with SPSS 17.0 software. The marginal fit of direct optical impression groups, silicone rubber impression groups, cast model groups was (69.18±9.47), (81.04±10.88), (84.42±9.96) µm. A significant difference was observed in the marginal fit of the direct optical impression groups and the other groups (P<0.05). No statistically significant difference was observed in the marginal fit of the silicone rubber impression groups and the cast model groups (P>0.05). All marginal measurement sites are clinically acceptable by the three different impression scanning methods. The silicone rubber impression scanning method can be used for all-ceramic restorations.

Impact of pneumoperitoneum on tumor growth.

PubMed

Lécuru, F; Agostini, A; Camatte, S; Robin, F; Aggerbeck, M; Jaïs, J P; Vilde, F; Taurelle, R

2002-08-01

To compare intraperitoneal tumor growth after CO2 laparoscopy (L), gasless laparoscopy (GL), midline laparotomy (ML), and general anesthesia (GA) as a control. A prospective randomized trial was carried out in nude rats. A carcinomatosis was obtained by intraperitoneal injection of either one of the two human ovarian cancer cell lines IGR-OV1 or NIH:OVCAR-3. Rats secondly underwent randomly different kind of procedures: CO2 L (8 mmHg, 60 min), GL (traction by a balloon for 60 min), ML (bowel removed and let on a mesh for 60 min), or GA. The rats were finally killed 10 or 35 days after surgery (respectively in IGR-OV1, or NIH:OVCAR-3 models). Tumor growth was assessed by the weight of the omental metastasis and MIB1 immunostaining. Peritoneal dissemination as well as abdominal wall metastases were assessed by pathological examination. Statistical analysis used the chi-square test (or Fisher exact test) and Bonferroni method for multiple comparison between groups. Fifteen rats were included in each group. Mean omental weight was significantly increased after surgery (3.1 to 5.6 g), when compared to control (2.4 g), but no significant difference was recorded between the three surgical accesses. MIB1 immunostaining was poor in the PNP group (37%), whereas it was higher after midline laparotomy (51%), but the difference was not significant (p = 0.07). Similarly, no significant variation was recorded in the NIH:OVCAR-3 model for omental weight or MIB1 staining. CO2 pneumoperitoneum significantly increased right diaphragmatic dome involvement in the NIH:OVCAR-3 model. Abdominal wall metastases were significantly more frequent after surgery when compared to the control group, but no significant difference could be demonstrated between surgical groups in each model. In these solid tumor models, CO2 pneumoperitoneum had no deleterious effect on tumor growth when compared to gasless laparoscopy or midline laparotomy.

Gender and Acceptance of E-Learning: A Multi-Group Analysis Based on a Structural Equation Model among College Students in Chile and Spain

PubMed Central

2015-01-01

The scope of this study was to evaluate whether the adoption of e-learning in two universities, and in particular, the relationship between the perception of external control and perceived ease of use, is different because of gender differences. The study was carried out with participating students in two different universities, one in Chile and one in Spain. The Technology Acceptance Model was used as a theoretical framework for the study. A multi-group analysis method in partial least squares was employed to relate differences between groups. The four main conclusions of the study are: (1) a version of the Technology Acceptance Model has been successfully used to explain the process of adoption of e-learning at an undergraduate level of study; (2) the finding of a strong and significant relationship between perception of external control and perception of ease of use of the e-learning platform; (3) a significant relationship between perceived enjoyment and perceived ease of use and between results demonstrability and perceived usefulness is found; (4) the study indicates a few statistically significant differences between males and females when adopting an e-learning platform, according to the tested model. PMID:26465895

[Effect of leptin on long-term spatial memory of rats with white matter damage in developing brain].

PubMed

Feng, Er-Cui; Jiang, Li

2017-12-01

To investigate the neuroprotective effect of leptin by observing its effect on spatial memory of rats with white matter damage in developing brain. A total of 80 neonatal rats were randomly divided into 3 groups: sham-operation (n=27), model (n=27) and leptin intervention (n=27). The rats in the model and leptin intervention groups were used to prepare a model of white matter damage in developing brain, and the rats in the leptin intervention group were given leptin (100 μg/kg) diluted with normal saline immediately after modelling for 4 consecutive days. The survival rate of the rats was observed and the change in body weight was monitored. When the rats reached the age of 21 days, the Morris water maze test was used to evaluate spatial memory. There was no significant difference in the survival rate of rats between the three groups (P>0.05). Within 10 days after birth, the leptin intervention group had similar body weight as the sham-operation group and significantly lower body weight than the model group (P<0.05); more than 10 days after birth, the leptin intervention group had rapid growth with higher body weight than the model and sham-operation groups (P>0.05). The results of place navigation showed that from the second day of experiment, there was a significant difference in the latency period between the three groups (P<0.05); from the fourth day of experiment, the leptin intervention group had a similar latency period as the sham-operation and a significantly shorter latency period than the model group (P<0.05). The results of space search experiment showed that compared with the sham-operation group, the model group had a significant reduction in the number of platform crossings and a significantly longer latency period (P<0.05); compared with the model group, the leptin intervention group had a significantly increased number of platform crossings and a significantly shortened latency period (P<0.05), while there was no significant difference between the leptin intervention and sham-operation groups. Leptin can alleviate spatial memory impairment of rats with white matter damage in developing brain. It thus exerts a neuroprotective effect, and is worthy of further research.

Projected loss of a salamander diversity hotspot as a consequence of projected global climate change.

PubMed

Milanovich, Joseph R; Peterman, William E; Nibbelink, Nathan P; Maerz, John C

2010-08-16

Significant shifts in climate are considered a threat to plants and animals with significant physiological limitations and limited dispersal abilities. The southern Appalachian Mountains are a global hotspot for plethodontid salamander diversity. Plethodontids are lungless ectotherms, so their ecology is strongly governed by temperature and precipitation. Many plethodontid species in southern Appalachia exist in high elevation habitats that may be at or near their thermal maxima, and may also have limited dispersal abilities across warmer valley bottoms. We used a maximum-entropy approach (program Maxent) to model the suitable climatic habitat of 41 plethodontid salamander species inhabiting the Appalachian Highlands region (33 individual species and eight species included within two species complexes). We evaluated the relative change in suitable climatic habitat for these species in the Appalachian Highlands from the current climate to the years 2020, 2050, and 2080, using both the HADCM3 and the CGCM3 models, each under low and high CO(2) scenarios, and using two-model thresholds levels (relative suitability thresholds for determining suitable/unsuitable range), for a total of 8 scenarios per species. While models differed slightly, every scenario projected significant declines in suitable habitat within the Appalachian Highlands as early as 2020. Species with more southern ranges and with smaller ranges had larger projected habitat loss. Despite significant differences in projected precipitation changes to the region, projections did not differ significantly between global circulation models. CO(2) emissions scenario and model threshold had small effects on projected habitat loss by 2020, but did not affect longer-term projections. Results of this study indicate that choice of model threshold and CO(2) emissions scenario affect short-term projected shifts in climatic distributions of species; however, these factors and choice of global circulation model have relatively small affects on what is significant projected loss of habitat for many salamander species that currently occupy the Appalachian Highlands.

Risk models of dating aggression across different adolescent relationships: a developmental psychopathology approach.

PubMed

Williams, Tricia S; Connolly, Jennifer; Pepler, Debra; Craig, Wendy; Laporte, Lise

2008-08-01

The present study examined physical dating aggression in different adolescent relationships and assessed linear, threshold, and moderator risk models for recurrent aggressive relationships. The 621 participants (59% girls, 41% boys) were drawn from a 1-year longitudinal survey of Canadian high school youths ranging from Grade 9 through Grade 12. Approximately 13% of participants reported recurrent dating aggression across 2 different relationships. Using peer and dyadic risk factors from Time 1 of the study, the authors confirmed a linear risk model, such that adolescents in 2 different violent relationships had significantly more contextual risk factors than did adolescents in 1 or no violent relationship. Further, structural equation modeling assessing moderation of contextual risk factors indicated that, for adolescents with high acceptance of dating aggression, peer aggression and delinquency significantly predicted recurrent aggression in a new relationship. In comparison, for adolescents with low acceptance of dating aggression, negative relationship characteristics significantly predicted recurrent aggression. Acceptance did not moderate concurrent associations between risk factors and aggression in 1 relationship. Results support a developmental psychopathological approach to the understanding of recurrent aggression and its associated risk factors. Copyright 2008 APA, all rights reserved.

Comparing the accuracy (trueness and precision) of models of fixed dental prostheses fabricated by digital and conventional workflows.

PubMed

Sim, Ji-Young; Jang, Yeon; Kim, Woong-Chul; Kim, Hae-Young; Lee, Dong-Hwan; Kim, Ji-Hwan

2018-03-31

This study aimed to evaluate and compare the accuracy. A reference model was prepared with three prepared teeth for three types of restorations: single crown, 3-unit bridge, and inlay. Stone models were fabricated from conventional impressions. Digital impressions of the reference model were created using an intraoral scanner (digital models). Physical models were fabricated using a three-dimensional (3D) printer. Reference, stone, and 3D printed models were subsequently scanned using an industrial optical scanner; files were exported in a stereolithography file format. All datasets were superimposed using 3D analysis software to evaluate the accuracy of the complete arch and trueness of the preparations. One-way and two-way analyses of variance (ANOVA) were performed to compare the accuracy among the three model groups and evaluate the trueness among the three types of preparation. For the complete arch, significant intergroup differences in precision were observed for the three groups (p<.001). However, no significant difference in trueness was found between the stone and digital models (p>.05). 3D printed models had the poorest accuracy. A two-way ANOVA revealed significant differences in trueness among the model groups (p<.001) and types of preparation (p<.001). Digital models had smaller root mean square values of trueness of the complete arch and preparations than stone models. However, the accuracy of the complete arch and trueness of the preparations of 3D printed models were inferior to those of the other groups. Copyright © 2018 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

Turbulent Chemical Interaction Models in NCC: Comparison

NASA Technical Reports Server (NTRS)

Norris, Andrew T.; Liu, Nan-Suey

2006-01-01

The performance of a scalar PDF hydrogen-air combustion model in predicting a complex reacting flow is evaluated. In addition the results are compared to those obtained by running the same case with the so-called laminar chemistry model and also a new model based on the concept of mapping partially stirred reactor data onto perfectly stirred reactor data. The results show that the scalar PDF model produces significantly different results from the other two models, and at a significantly higher computational cost.

Comparison of small diameter stone baskets in an in vitro caliceal and ureteral model.

PubMed

Korman, Emily; Hendlin, Kari; Chotikawanich, Ekkarin; Monga, Manoj

2011-01-01

Three small diameter (<1.5F) stone baskets have recently been introduced. Our objective was to evaluate the stone capture rate of these baskets in an in vitro ureteral model and an in vitro caliceal model using novice, resident, and expert operators. Sacred Heart Medical Halo™ (1.5F), Cook N-Circle(®) Nitinol Tipless Stone Extractor (1.5F), and Boston Scientific OptiFlex(®) (1.3F) stone baskets were tested in an in vitro ureteral and a caliceal model by three novices, three residents, and three experts. The caliceal model consisted of a 7-cm length of 10-mm O.D. plastic tubing with a convex base. Each operator was timed during removal of a 3-mm calculus from each model with three repetitions for each basket. Data were analyzed by analysis of variance single factor tests and t tests assuming unequal variances. In the ureteral model, the Halo had the fastest average rate of stone extraction for experts and novices (0:02 ± 0:01 and 0:08 ± 0:04 min, respectively), as well as the overall fastest average stone extraction rate (0:08 ± 0:06 min). No statistical significant differences in extraction times between baskets were identified in the resident group. In the novice group, the Halo stone extraction rate was significantly faster than the OptiFlex (P=0.029). In the expert group, the OptiFlex had statistically significant slower average extraction rates compared with the Halo (P=0.005) and the N-Circle (P=0.017). In the caliceal model, no statistically significant differences were noted. While no significant differences were noted in extraction times for the caliceal model, the extraction times for the ureteral model were slowest with the OptiFlex basket. Other variables important in selection of the appropriate basket include operator preference, clinical setting, and cost.

HCMM energy budget data as a model input for assessing regions of high potential groundwater pollution

NASA Technical Reports Server (NTRS)

Moore, D. G. (Principal Investigator); Tunheim, J. A.; Heilman, J.

1977-01-01

The author has identified the following significant results. The finite difference model was used to calculate the differences in surface temperature between two hypothetical sites which result from a temperature difference at 50 cm due to the presence of shallow ground water at one of the sites. Although qualitative results of the model seemed consistant with experimental results, further evaluation showed a need for taking account of differences in thermal conductivity due to different moisture profiles at the two sites considered.

Spatial Distribution of Hydrologic Ecosystem Service Estimates: Comparing Two Models

NASA Astrophysics Data System (ADS)

Dennedy-Frank, P. J.; Ghile, Y.; Gorelick, S.; Logsdon, R. A.; Chaubey, I.; Ziv, G.

2014-12-01

We compare estimates of the spatial distribution of water quantity provided (annual water yield) from two ecohydrologic models: the widely-used Soil and Water Assessment Tool (SWAT) and the much simpler water models from the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) toolbox. These two models differ significantly in terms of complexity, timescale of operation, effort, and data required for calibration, and so are often used in different management contexts. We compare two study sites in the US: the Wildcat Creek Watershed (2083 km2) in Indiana, a largely agricultural watershed in a cold aseasonal climate, and the Upper Upatoi Creek Watershed (876 km2) in Georgia, a mostly forested watershed in a temperate aseasonal climate. We evaluate (1) quantitative estimates of water yield to explore how well each model represents this process, and (2) ranked estimates of water yield to indicate how useful the models are for management purposes where other social and financial factors may play significant roles. The SWAT and InVEST models provide very similar estimates of the water yield of individual subbasins in the Wildcat Creek Watershed (Pearson r = 0.92, slope = 0.89), and a similar ranking of the relative water yield of those subbasins (Spearman r = 0.86). However, the two models provide relatively different estimates of the water yield of individual subbasins in the Upper Upatoi Watershed (Pearson r = 0.25, slope = 0.14), and very different ranking of the relative water yield of those subbasins (Spearman r = -0.10). The Upper Upatoi watershed has a significant baseflow contribution due to its sandy, well-drained soils. InVEST's simple seasonality terms, which assume no change in storage over the time of the model run, may not accurately estimate water yield processes when baseflow provides such a strong contribution. Our results suggest that InVEST users take care in situations where storage changes are significant.

Energy- and wave-based beam-tracing prediction of room-acoustical parameters using different boundary conditions.

PubMed

Yousefzadeh, Behrooz; Hodgson, Murray

2012-09-01

A beam-tracing model was used to study the acoustical responses of three empty, rectangular rooms with different boundary conditions. The model is wave-based (accounting for sound phase) and can be applied to rooms with extended-reaction surfaces that are made of multiple layers of solid, fluid, or poroelastic materials-the acoustical properties of these surfaces are calculated using Biot theory. Three room-acoustical parameters were studied in various room configurations: sound strength, reverberation time, and RApid Speech Transmission Index. The main objective was to investigate the effects of modeling surfaces as either local or extended reaction on predicted values of these three parameters. Moreover, the significance of modeling interference effects was investigated, including the study of sound phase-change on surface reflection. Modeling surfaces as of local or extended reaction was found to be significant for surfaces consisting of multiple layers, specifically when one of the layers is air. For multilayers of solid materials with an air-cavity, this was most significant around their mass-air-mass resonance frequencies. Accounting for interference effects made significant changes in the predicted values of all parameters. Modeling phase change on reflection, on the other hand, was found to be relatively much less significant.

The Study of Different Approaches of Parecoxib Sodium Pretreatment on the Behavior of Rats with Neuropathic Pain.

PubMed

Cui, Wenyao; Yu, Xue; Zhang, Huiqian

2015-05-01

Our objective is to analyze and observe the different administration routes of parecoxib sodium pretreatment on the behavioral improvement of rats with neuropathic pain to provide the preclinical data of parecoxib sodium on neuropathic pain treatment. 30 SD rats were randomly divided into five groups, including model group, sham operation group, intrathecal injection group (IT group), intraperitoneal injection group (IP group), and perineural infiltration group (PI group). The rats in model group and three parecoxib sodium pretreatment groups received spinal nerve ligation (SNL). Heat pain test and 50 % paw mechanical withdrawal threshold test (50 % PMWT) were use to assess the responses after parecoxib sodium pretreatment. 50 % PMWT results of right foot in five groups had no statistical difference (P > 0.05); 50 % PMWT results of left and right feet in three parecoxib sodium pretreatment groups were obviously higher than SNL group at different time points, which was statistically different (P < 0.05); in comparison with three pretreatment groups, the data of left foot in IT group were obviously higher than PI group and IP group, and the comparison among three groups had significant difference (P < 0.05). However, the data of right foot had no significant difference among three groups (P > 0.05). Paw thermal withdrawal latency (PTWL) results of left and right feet in five groups had no significant difference before surgery (P > 0.05); after the establishment of neuropathic model, PTWL results in five groups were significantly decreased; however, PTWL results of left and right feet at 3 days after surgery in IT group were significantly higher than the two other pretreatment groups (P < 0.05); PTWL results of left and right feet at 7 and 14 days after surgery had no significant difference. Parecoxib sodium pretreatment can effectively improve the behaviors caused by neuropathic pain, and intrathecal injection is the most effective route of administration.

Advanced Statistical Analyses to Reduce Inconsistency of Bond Strength Data.

PubMed

Minamino, T; Mine, A; Shintani, A; Higashi, M; Kawaguchi-Uemura, A; Kabetani, T; Hagino, R; Imai, D; Tajiri, Y; Matsumoto, M; Yatani, H

2017-11-01

This study was designed to clarify the interrelationship of factors that affect the value of microtensile bond strength (µTBS), focusing on nondestructive testing by which information of the specimens can be stored and quantified. µTBS test specimens were prepared from 10 noncarious human molars. Six factors of µTBS test specimens were evaluated: presence of voids at the interface, X-ray absorption coefficient of resin, X-ray absorption coefficient of dentin, length of dentin part, size of adhesion area, and individual differences of teeth. All specimens were observed nondestructively by optical coherence tomography and micro-computed tomography before µTBS testing. After µTBS testing, the effect of these factors on µTBS data was analyzed by the general linear model, linear mixed effects regression model, and nonlinear regression model with 95% confidence intervals. By the general linear model, a significant difference in individual differences of teeth was observed ( P < 0.001). A significantly positive correlation was shown between µTBS and length of dentin part ( P < 0.001); however, there was no significant nonlinearity ( P = 0.157). Moreover, a significantly negative correlation was observed between µTBS and size of adhesion area ( P = 0.001), with significant nonlinearity ( P = 0.014). No correlation was observed between µTBS and X-ray absorption coefficient of resin ( P = 0.147), and there was no significant nonlinearity ( P = 0.089). Additionally, a significantly positive correlation was observed between µTBS and X-ray absorption coefficient of dentin ( P = 0.022), with significant nonlinearity ( P = 0.036). A significant difference was also observed between the presence and absence of voids by linear mixed effects regression analysis. Our results showed correlations between various parameters of tooth specimens and µTBS data. To evaluate the performance of the adhesive more precisely, the effect of tooth variability and a method to reduce variation in bond strength values should also be considered.

Testing the Cultural Differences of School Characteristics with Measurement Invariance

ERIC Educational Resources Information Center

Demir, Ergül

2016-01-01

In this study, it was aimed to model the school characteristics in multivariate structure, and according to this model, aimed to test the invariance of this model across five randomly selected countries and economies from PISA 2012 sample. It is thought that significant differences across group in the context of school characteristics have the…

Significance of exchanging SSURGO and STATSGO data when modeling hydrology in diverse physiographic terranes

USGS Publications Warehouse

Williamson, Tanja N.; Taylor, Charles J.; Newson, Jeremy K.

2013-01-01

The Water Availability Tool for Environmental Resources (WATER) is a TOPMODEL-based hydrologic model that depends on spatially accurate soils data to function in diverse terranes. In Kentucky, this includes mountainous regions, karstic plateau, and alluvial plains. Soils data are critical because they quantify the space to store water, as well as how water moves through the soil to the stream during storm events. We compared how the model performs using two different sources of soils data--Soil Survey Geographic Database (SSURGO) and State Soil Geographic Database laboratory data (STATSGO)--for 21 basins ranging in size from 17 to 1564 km2. Model results were consistently better when SSURGO data were used, likely due to the higher field capacity, porosity, and available-water holding capacity, which cause the model to store more soil-water in the landscape and improve streamflow estimates for both low- and high-flow conditions. In addition, there were significant differences in the conductivity multiplier and scaling parameter values that describe how water moves vertically and laterally, respectively, as quantified by TOPMODEL. We also evaluated whether partitioning areas that drain to streams via sinkholes in karstic basins as separate hydrologic modeling units (HMUs) improved model performance. There were significant differences between HMUs in properties that control soil-water storage in the model, although the effect of partitioning these HMUs on streamflow simulation was inconclusive.

Model Forecast Skill and Sensitivity to Initial Conditions in the Seasonal Sea Ice Outlook

NASA Technical Reports Server (NTRS)

Blanchard-Wrigglesworth, E.; Cullather, R. I.; Wang, W.; Zhang, J.; Bitz, C. M.

2015-01-01

We explore the skill of predictions of September Arctic sea ice extent from dynamical models participating in the Sea Ice Outlook (SIO). Forecasts submitted in August, at roughly 2 month lead times, are skillful. However, skill is lower in forecasts submitted to SIO, which began in 2008, than in hindcasts (retrospective forecasts) of the last few decades. The multimodel mean SIO predictions offer slightly higher skill than the single-model SIO predictions, but neither beats a damped persistence forecast at longer than 2 month lead times. The models are largely unsuccessful at predicting each other, indicating a large difference in model physics and/or initial conditions. Motivated by this, we perform an initial condition sensitivity experiment with four SIO models, applying a fixed -1 m perturbation to the initial sea ice thickness. The significant range of the response among the models suggests that different model physics make a significant contribution to forecast uncertainty.

Comparison of three chronic dialysis models.

PubMed

Peng, W X; Guo, Q Y; Liu, S M; Liu, C Z; Lindholm, B; Wang, T

2000-01-01

The chronic peritoneal dialysis model is important for understanding the pathophysiology of peritoneal transport and for studying biocompatibility of peritoneal dialysis solutions. In this study, we compared three different chronic peritoneal dialysis models. A peritoneal catheter was placed in 23 male Sprague-Dawley rats, 12 of which had an intact omentum (model 1) and 11 of which received an omentectomy (model 2). Seven other rats, without a catheter, received a daily intraperitoneal injection (model 3). Each rat received a daily infusion of 25 mL of 3.86% glucose dialysis solution either through the catheter (models 1 and 2) or through injection (model 3) for 4 weeks. Then, a 4-hour dwell study using 3.86% glucose solution with an intraperitoneal volume marker and frequent dialysate and blood sampling was performed in each rat. The intraperitoneal volume was significantly lower in all the dialysis groups as compared to a control group (n = 6) in which the rats had no chronic dialysate exposure. The peritoneal fluid absorption rate, as well as the direct lymphatic absorption rate, was significantly higher in the three dialysis groups as compared to the control group. In general, no significant differences were seen in any of the parameters among the three dialysis models. Owing to catheter obstruction, three rats in model 1 and four rats in model 2 were lost during dialysis. Histological examination showed no significant differences among the three dialysis groups. Our results suggest that omentectomy may not be necessary in the chronic peritoneal dialysis model when using dialysate infusion and no drainage. Based on the present study, we think that perhaps model 1 may be the method of choice to test new peritoneal dialysis solutions. However, owing to its simplicity, model 3 could also be used if great care is taken to avoid puncturing the intestine or injecting into the abdominal wall.

Red Brain, Blue Brain: Evaluative Processes Differ in Democrats and Republicans

PubMed Central

Schreiber, Darren; Fonzo, Greg; Simmons, Alan N.; Dawes, Christopher T.; Flagan, Taru; Fowler, James H.; Paulus, Martin P.

2013-01-01

Liberals and conservatives exhibit different cognitive styles and converging lines of evidence suggest that biology influences differences in their political attitudes and beliefs. In particular, a recent study of young adults suggests that liberals and conservatives have significantly different brain structure, with liberals showing increased gray matter volume in the anterior cingulate cortex, and conservatives showing increased gray matter volume in the in the amygdala. Here, we explore differences in brain function in liberals and conservatives by matching publicly-available voter records to 82 subjects who performed a risk-taking task during functional imaging. Although the risk-taking behavior of Democrats (liberals) and Republicans (conservatives) did not differ, their brain activity did. Democrats showed significantly greater activity in the left insula, while Republicans showed significantly greater activity in the right amygdala. In fact, a two parameter model of partisanship based on amygdala and insula activations yields a better fitting model of partisanship than a well-established model based on parental socialization of party identification long thought to be one of the core findings of political science. These results suggest that liberals and conservatives engage different cognitive processes when they think about risk, and they support recent evidence that conservatives show greater sensitivity to threatening stimuli. PMID:23418419

Improved system identification using artificial neural networks and analysis of individual differences in responses of an identified neuron.

PubMed

Costalago Meruelo, Alicia; Simpson, David M; Veres, Sandor M; Newland, Philip L

2016-03-01

Mathematical modelling is used routinely to understand the coding properties and dynamics of responses of neurons and neural networks. Here we analyse the effectiveness of Artificial Neural Networks (ANNs) as a modelling tool for motor neuron responses. We used ANNs to model the synaptic responses of an identified motor neuron, the fast extensor motor neuron, of the desert locust in response to displacement of a sensory organ, the femoral chordotonal organ, which monitors movements of the tibia relative to the femur of the leg. The aim of the study was threefold: first to determine the potential value of ANNs as tools to model and investigate neural networks, second to understand the generalisation properties of ANNs across individuals and to different input signals and third, to understand individual differences in responses of an identified neuron. A metaheuristic algorithm was developed to design the ANN architectures. The performance of the models generated by the ANNs was compared with those generated through previous mathematical models of the same neuron. The results suggest that ANNs are significantly better than LNL and Wiener models in predicting specific neural responses to Gaussian White Noise, but not significantly different when tested with sinusoidal inputs. They are also able to predict responses of the same neuron in different individuals irrespective of which animal was used to develop the model, although notable differences between some individuals were evident. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Weak simulated extratropical responses to complete tropical deforestation

USGS Publications Warehouse

Findell, K.L.; Knutson, T.R.; Milly, P.C.D.

2006-01-01

The Geophysical Fluid Dynamics Laboratory atmosphere-land model version 2 (AM2/LM2) coupled to a 50-m-thick slab ocean model has been used to investigate remote responses to tropical deforestation. Magnitudes and significance of differences between a control run and a deforested run are assessed through comparisons of 50-yr time series, accounting for autocorrelation and field significance. Complete conversion of the broadleaf evergreen forests of South America, central Africa, and the islands of Oceania to grasslands leads to highly significant local responses. In addition, a broad but mild warming is seen throughout the tropical troposphere (<0.2??C between 700 and 150 mb), significant in northern spring and summer. However, the simulation results show very little statistically significant response beyond the Tropics. There are no significant differences in any hydroclimatic variables (e.g., precipitation, soil moisture, evaporation) in either the northern or the southern extratropics. Small but statistically significant local differences in some geopotential height and wind fields are present in the southeastern Pacific Ocean. Use of the same statistical tests on two 50-yr segments of the control run show that the small but significant extratropical differences between the deforested run and the control run are similar in magnitude and area to the differences between nonoverlapping segments of the control run. These simulations suggest that extratropical responses to complete tropical deforestation are unlikely to be distinguishable from natural climate variability.

Comparative structural neck responses of the THOR-NT, Hybrid III, and human in combined tension-bending and pure bending.

PubMed

Dibb, Alan T; Nightingale, Roger W; Chancey, V Carol; Fronheiser, Lucy E; Tran, Laura; Ottaviano, Danielle; Meyers, Barry S

2006-11-01

This study evaluated the biofidelity of both the Hybrid III and the THOR-NT anthropomorphic test device (ATD) necks in quasistatic tension-bending and pure-bending by comparing the responses of both the ATDs with results from validated computational models of the living human neck. This model was developed using post-mortem human surrogate (PMHS) osteoligamentous response corridors with effective musculature added (Chancey, 2005). Each ATD was tested using a variety of end-conditions to create the tension-bending loads. The results were compared using absolute difference, RMS difference, and normalized difference metrics. The THOR-NT was tested both with and without muscle cables. The THOR-NT was also tested with and without the central safety cable to test the effect of the cable on the behavior of the ATD. The Hybrid III was stiffer than the model for all tension-bending end conditions. Quantitative measurement of the differences in response showed more close agreement between the THOR-NT and the model than the Hybrid III and the model. By contrast, no systematic differences were observed in the head kinematics. The muscle cables significantly stiffened the THOR-NT by effectively reducing the laxity from the occipital condyle (OC) joint. The cables also shielded the OC upper neck load cell from a significant portion of the applied loads. The center safety significantly stiffened the response and decreased the fidelity, particularly in modes of loading in which tensile forces were large and bending moments small. This study compares ATD responses to computational models in which the models include PMHS response corridors while correcting for problems associated with cadaveric muscle. While controversial and requiring considerable diligence, these kinds of approaches show promise in assessing ATD biofidelity.

Schwann Cells Transplantation Improves Locomotor Recovery in Rat Models with Spinal Cord Injury: a Systematic Review and Meta-Analysis.

PubMed

Yang, Lei; Ge, Yingbin; Tang, Jian; Yuan, Jinxia; Ge, Dawei; Chen, Hongtao; Zhang, Hongxiu; Cao, Xiaojian

2015-01-01

Schwann cells (SCs) which were demonstrated to be responsible for axonal myelination and ensheathing are widely studied and commonly used for cell transplantation to treat spinal cord injury (SCI). We performed this meta-analysis to summarize the effects of SCs versus controls for locomotor recovery in rat models of traumatic SCI. Studies of the BBB scores after transplantation of SCs were searched out from Pubmed, Cochrane Library Medline databases and analyzed by Review Manager 5.2.5. Thirteen randomized controlled animal trials were selected with 283 rats enrolled. The studies were divided to different subgroups by different models of SCI, different cell doses for transplantation, different sources of SCs and different transplantation ways. The pooled results of this meta-analysis suggested that SCs transplantation cannot significantly improve the locomotor recovery at a short time after intervention (1 week after transplantation) in both impacted and hemi-sected SCI models. However, at a longer time after intervention (3, 5-7 and over 8 weeks after transplantation), significant improvement of BBB score emerged in SCs groups compared with control groups. Subgroup analyses revealed that SCs transplantation can significantly promote locomotor recovery regardless of in high or low doses of cells, from different sources (isolated from sciatic nerves or differentiated from bone marrow stromal cells(BMSCs)) and with or without scaffolding. SCs seem to demonstrate substantial beneficial effects on locomotor recovery in a widely-used animal models of SCI. © 2015 The Author(s) Published by S. Karger AG, Basel.

Neck Muscle Moment Arms Obtained In-Vivo from MRI: Effect of Curved and Straight Modeled Paths.

PubMed

Suderman, Bethany L; Vasavada, Anita N

2017-08-01

Musculoskeletal models of the cervical spine commonly represent neck muscles with straight paths. However, straight lines do not best represent the natural curvature of muscle paths in the neck, because the paths are constrained by bone and soft tissue. The purpose of this study was to estimate moment arms of curved and straight neck muscle paths using different moment arm calculation methods: tendon excursion, geometric, and effective torque. Curved and straight muscle paths were defined for two subject-specific cervical spine models derived from in vivo magnetic resonance images (MRI). Modeling neck muscle paths with curvature provides significantly different moment arm estimates than straight paths for 10 of 15 neck muscles (p < 0.05, repeated measures two-way ANOVA). Moment arm estimates were also found to be significantly different among moment arm calculation methods for 11 of 15 neck muscles (p < 0.05, repeated measures two-way ANOVA). In particular, using straight lines to model muscle paths can lead to overestimating neck extension moment. However, moment arm methods for curved paths should be investigated further, as different methods of calculating moment arm can provide different estimates.

Revised radiobiological modelling of the contribution of synchronous chemotherapy to the rate of grades 3-4 mucositis in head and neck cancer.

PubMed

Meade, Sara; McConkey, Chris; Sanghera, Paul; Mehanna, Hisham; Hartley, Andrew

2013-12-01

Biological effective dose (BED) calculations modelled on reduced accelerated repopulation when synchronous chemotherapy is delivered significantly correlate with observed differences in local control in randomised trials of platinum-based chemoradiation. The purpose of this study was to examine whether a similar relationship existed in the context of grades 3-4 mucositis. Biological effective dose from radiotherapy and synchronous chemotherapy was calculated using three different models: AB using the additional BED attributable to chemotherapy and standard repopulation parameters; zero repopulation (ZRP) using zero correction for repopulation; and variable t(p) (Vt(p)) using a variable doubling time for mucosal stem cell repopulation. The correlation between the percentage change in biological effective dose between trial arms, and the observed percentage change in the rate of grades 3-4 mucositis was examined by using the Pearson product-moment correlation. With the AB model, there were no significant correlations with observed differences in rates of grades 3-4 mucositis. With either the ZRP or Vt(p) models, significant correlations were observed. A value of 5 days for the doubling time during repopulation (T(p)) was associated with the most significant correlation (P = 0.002). Models where the dose lost due to accelerated repopulation is reduced imply a therapeutic loss from the use of synchronous chemotherapy when only local control and the rate of acute grades 3-4 mucositis are considered. © 2013 The Royal Australian and New Zealand College of Radiologists.

Assessment of Sex Differences in Body Composition Among Adolescents With Anorexia Nervosa.

PubMed

Nagata, Jason M; Golden, Neville H; Peebles, Rebecka; Long, Jin; Murray, Stuart B; Leonard, Mary B; Carlson, Jennifer L

2017-04-01

To compare deficits in fat mass (FM) and lean body mass (LM) among male and female adolescents with anorexia nervosa (AN) and to identify other covariates associated with body composition. We retrospectively reviewed electronic medical records of all subjects aged 9-20 years with a Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition diagnosis of AN and dual-energy x-ray absorptiometry scans after initial evaluation at Stanford between March 1997 and February 2011. From the dual-energy x-ray absorptiometry scans, LM and FM results were converted to age-, height-, sex-, and race-specific Z-scores for age using the National Health and Nutrition Examination Survey reference data. A total of 16 boys and 119 girls with AN met eligibility criteria. The FM Z-score in girls with AN (-3.24 ± 1.50) was significantly lower than that in boys with AN (-2.41 ± .96) in unadjusted models (p = .007). LM was reduced in both girls and boys with AN, but there was no significant sex difference in LM Z-scores. In multivariate models, lower percentage median body mass index was significantly associated with lower FM Z-scores (β = .08, p < .0001) and lower LM Z-score (β = .03, p = .0002), whereas lower whole body bone mineral content Z-score was significantly associated with lower LM Z-score (β = .21, p = .0006). FM deficits in girls were significantly greater than those in boys with AN in unadjusted models; however, the degree of malnutrition appeared to be the primary factor accounting for this difference. There were no significant sex differences in FM or LM in adjusted models. Copyright © 2016 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

Appending Limited Clinical Data to an Administrative Database for Acute Myocardial Infarction Patients: The Impact on the Assessment of Hospital Quality.

PubMed

Hannan, Edward L; Samadashvili, Zaza; Cozzens, Kimberly; Jacobs, Alice K; Venditti, Ferdinand J; Holmes, David R; Berger, Peter B; Stamato, Nicholas J; Hughes, Suzanne; Walford, Gary

2016-05-01

Hospitals' risk-standardized mortality rates and outlier status (significantly higher/lower rates) are reported by the Centers for Medicare and Medicaid Services (CMS) for acute myocardial infarction (AMI) patients using Medicare claims data. New York now has AMI claims data with blood pressure and heart rate added. The objective of this study was to see whether the appended database yields different hospital assessments than standard claims data. New York State clinically appended claims data for AMI were used to create 2 different risk models based on CMS methods: 1 with and 1 without the added clinical data. Model discrimination was compared, and differences between the models in hospital outlier status and tertile status were examined. Mean arterial pressure and heart rate were both significant predictors of mortality in the clinically appended model. The C statistic for the model with the clinical variables added was significantly higher (0.803 vs. 0.773, P<0.001). The model without clinical variables identified 10 low outliers and all of them were percutaneous coronary intervention hospitals. When clinical variables were included in the model, only 6 of those 10 hospitals were low outliers, but there were 2 new low outliers. The model without clinical variables had only 3 high outliers, and the model with clinical variables included identified 2 new high outliers. Appending even a small number of clinical data elements to administrative data resulted in a difference in the assessment of hospital mortality outliers for AMI. The strategy of adding limited but important clinical data elements to administrative datasets should be considered when evaluating hospital quality for procedures and other medical conditions.

The effect of age and speed on foot and ankle kinematics assessed using a 4-segment foot model.

PubMed

van Hoeve, Sander; Leenstra, Bernard; Willems, Paul; Poeze, Martijn; Meijer, Kenneth

2017-09-01

The effects of age and speed on foot and ankle kinematics in gait studies using foot models are not fully understood, whereas this can have significant influence. We analyzed these variables with the 4-segment Oxford foot model. Twenty-one healthy subjects (aged 20-65 years) were recruited for gait analysis. The effect of speed on foot and ankle kinematics was assessed by comparing results during slow walking and fast walking. To assess the effect of age, a group of 13 healthy young adults (aged 20-24 years) were compared with a group of 8 older adults (aged 53-65 years). Also, the interaction between age and speed was analyzed. Regarding speed, there was a significant difference between forefoot/hindfoot motion in the sagittal plane (flexion/extension) during both loading- and push-off phase (P = .004, P < .001). Between hindfoot/tibia, there was a significant difference for all parameters except for motion in the sagittal plane (flexion/extension) during push-off phase (P = .5). Age did not significantly influence kinematics. There was no interaction between age and speed. Our analysis found that speed significantly influenced the kinematic outcome parameters. This was more pronounced in the ankle joint. In contrast, no significant differences were found between younger and older healthy subjects.

Development of a waterborne challenge model for Flavobacterium psychrophilum.

PubMed

Long, Amy; Fehringer, Tyson R; LaFrentz, Benjamin R; Call, Douglas R; Cain, Kenneth D

2014-10-01

Flavobacterium psychrophilum is the causative agent of bacterial coldwater disease and can cause significant mortality in salmonid aquaculture. To better evaluate disease prevention or treatment methods for F. psychrophilum in the laboratory, a waterborne challenge model that mimics a natural outbreak is needed. Here we report on the development of a waterborne challenge model for F. psychrophilum in which we incorporated variables that may influence challenge success: specifically, scarification prior to bacterial exposure and culture of F. psychrophilum under iron-limited culture conditions to potentially increase the probability of establishing disease. Additionally, two F. psychrophilum strains, CSF 259-93 and THC 02-90, were used in this model to test whether there were virulence differences between strains. Mortality was significantly higher in scarred fish than unscarred fish (81.5 vs. 19.4%), supporting the hypothesis that disruptions in the dermal layer enhance mortality in F. psychrophilum waterborne challenges. Although mortality differences were not significant between iron-replete and iron-limited treatments, mortality was high overall (> 30%). There was a significant difference in mortality between CSF 259-93 and THC 02-90 treatments, although both strains caused high mortality in injection challenges. In conclusion, this waterborne challenge model can be used to evaluate potential disease prevention and treatment methods. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

Protonation of Different Goethite Surfaces - Unified Models for NaNO3 and NaCl Media.

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

Lutzenkirchen, Johannes; Boily, Jean F.; Gunneriusson, Lars

2008-01-01

Acid-base titration data for two goethites samples in sodium nitrate and sodium chloride media are discussed. The data are modelled based on various surface complexation models in the framework of the MUlti SIte Complexation (MUSIC) model. Various assumptions with respect to the goethite morphology are considered in determining the site density of the surface functional groups. The results from the various model applications are not statistically significant in terms of goodness of fit. More importantly, various published assumptions with respect to the goethite morphology (i.e. the contributions of different crystal planes and their repercussions on the “overall” site densities ofmore » the various surface functional groups) do not significantly affect the final model parameters. The simultaneous fit of the chloride and nitrate data results in electrolyte binding constants, which are applicable over a wide range of electrolyte concentrations including mixtures of chloride and nitrate. Model parameters for the high surface area goethite sample are in excellent agreement with parameters that were independently obtained by another group on different goethite titration data sets.« less

[Leisure activities, resilience and mental stress in adolescents].

PubMed

Karpinski, Norbert; Popal, Narges; Plück, Julia; Petermann, Franz; Lehmkuhl, Gerd

2017-01-01

To date, the factors contributing to emergence of resilience in different stages of adolescence have yet to be sufficiently examined. This study looks at the influence of extracurricular activities on resilience. The sample consists of 413 adolescents (f = 14.8) reporting personal problems (mood, concentration problems, behavior). The effect of extracurricular activities on resilience (gathered by the RS25) was analyzed by linear regression models. Predictor variables in these models were extracurricular activities (sport, hobbies, club memberships, household duties) and the subscales of the SDQ (Strengths and Difficulties Questionnaire). Because of the lack of homoscedasticity, two different regression models (model A: Realschule and Grammar School. Model B: Hauptschule) were specified. The explained variance of both models (model A: R = .516; model B: R = .643) is satisfactory. In both models “prosocial behavior” (SDQ) turns out to be a significant positive predictor for resilience (model A: b = 2.815; model B; b = 3.577) and emotional symptoms (model A: b = -1.697; model B: b = -2.596) are significant negative predictors for resilience. In addition, model A presents significant positive influences of sport (b = 16,314) and significant negative influences of “hyperactivity” (SDQ). In contrast, in model B “club memberships” (b = 15.775) and” peer relationship problems” (b = 1.508) are additional positive predictors. The results of the study demonstrate the important role of prosocial behavior and emotional competence in the manifestation of resilience. The effect of extracurricular activities proves to depend on the social environment (type of school). Thus, these results could form the basis for further more specific developmental programs.

Cultural differences in the imitation and transmission of inefficient actions.

PubMed

Corriveau, Kathleen H; DiYanni, Cara J; Clegg, Jennifer M; Min, Grace; Chin, Jason; Nasrini, Jad

2017-09-01

Across two studies, we explored cultural differences in children's imitation and transmission of inefficient actions. Chinese American and Caucasian American preschoolers (N=115) viewed either one or three models using two inefficient tools to perform two different tasks. In the video, when the model(s) performed the task, only the inefficient tool was available; thus, their choice to use that tool could be considered rational. Next, children were invited to complete the task with either the inefficient tool or an efficient alternative. Whereas the two cultural groups imitated a single model at similar rates, Chinese American children imitated significantly more than Caucasian American children after viewing a consensus. Similar results were found when exploring differences in information transmission. The Chinese American children were significantly more likely than their Caucasian American peers to instruct using an inefficient tool when they had initially viewed a consensus demonstrate it. We discuss these findings with respect to differences in children's use of social versus task-specific cues for learning and teaching. Copyright © 2017 Elsevier Inc. All rights reserved.

Adapting an Agent-Based Model of Socio-Technical Systems to Analyze Security Failures

DTIC Science & Technology

2016-10-17

total number of non-blackouts differed from the total number in the baseline data to a statistically significant extent with a p- valueɘ.0003...the total number of non-blackouts differed from the total number in the baseline data to a statistically significant extent with a p-valueɘ.0003...I. Nikolic, and Z. Lukszo, Eds., Agent-based modelling of socio-technical systems. Springer Science & Business Media, 2013, vol. 9. [12] A. P. Shaw

MX Survivability: Passive and Active Defense.

DTIC Science & Technology

1982-03-01

coefficient of determination (K2) and model parameters (i.e., bo, b1 , b2 , and b3 ) significantly different from zero: MX Survivability = 0 + b1X1...following equation was chosen as the best fit for the data: MX Survivability - b° + blX1 , - 0.881 where F-Ratio b = .2884 49.26 b1 - .02695 112.46 X1...that all of the model parameters estimated (i.e., b and b1 ) are significantly different from zero. Substituting 60% MX survivability into this equation

More Realistic Face Model Surface Improves Relevance of Pediatric In-Vitro Aerosol Studies

PubMed Central

Amirav, Israel; Halamish, Asaf; Gorenberg, Miguel; Omar, Hamza; Newhouse, Michael T.

2015-01-01

Background Various hard face models are commonly used to evaluate the efficiency of aerosol face masks. Softer more realistic “face” surface materials, like skin, deform upon mask application and should provide more relevant in-vitro tests. Studies that simultaneously take into consideration many of the factors characteristic of the in vivo face are lacking. These include airways, various application forces, comparison of various devices, comparison with a hard-surface model and use of a more representative model face based on large numbers of actual faces. Aim To compare mask to “face” seal and aerosol delivery of two pediatric masks using a soft vs. a hard, appropriately representative, pediatric face model under various applied forces. Methods Two identical face models and upper airways replicas were constructed, the only difference being the suppleness and compressibility of the surface layer of the “face.” Integrity of the seal and aerosol delivery of two different masks [AeroChamber (AC) and SootherMask (SM)] were compared using a breath simulator, filter collection and realistic applied forces. Results The soft “face” significantly increased the delivery efficiency and the sealing characteristics of both masks. Aerosol delivery with the soft “face” was significantly greater for the SM compared to the AC (p< 0.01). No statistically significant difference between the two masks was observed with the hard “face.” Conclusions The material and pliability of the model “face” surface has a significant influence on both the seal and delivery efficiency of face masks. This finding should be taken into account during in-vitro aerosol studies. PMID:26090661

Effect of Orem's Self-Care Model on Self-Esteem of Adolescents with Asthma Referred to an Asthma and Allergy Clinic in Isfahan.

PubMed

Hemati, Zeinab; Mosaviasl, Fatemeh Sadat; Abasi, Samira; Ghazavi, Zohre; Kiani, Davood

2015-01-01

Acquisition of chronic diseases such as asthma leads to psychological, mental and physical complications in adolescents, and hence their self-esteem may be compromised. Therefore, the present study was conducted to assess the effect of Orem's self-care model on self-esteem of adolescents with asthma. This semi-experimental study enrolled 64 asthmatic adolescents referred to Shariati Hospital, Isfahan. Subjects were assigned to two groups of control and intervention consecutively. Then, the self-care training program was conducted according to Orem's self-care model in eight two-hour sessions based on self-care needs, and self-esteem was measured in the two groups prior to and two months after the last training session. The data were collected by a questionnaire of demographic characteristics and the Coopersmith Self-Esteem Inventories (CSEI) and analyzed by SPSS version 20. Independent t-test showed a significant difference in the mean score of self-esteem between the intervention and control groups after the training (P<0.05), but the difference was not statistically significant prior to the intervention. Paired t-test showed a significant difference in the mean score of self-esteem before and after the training in the intervention group (P<0.01), but this difference was not statistically significant in the control group (P>0.05). Regarding the effect of Orem's self-care model on self-esteem of adolescents with asthma, we recommend the use of this model as a care intervention in healthcare centers to promote adolescents' health.

Modeling seasonal variation of hip fracture in Montreal, Canada.

PubMed

Modarres, Reza; Ouarda, Taha B M J; Vanasse, Alain; Orzanco, Maria Gabriela; Gosselin, Pierre

2012-04-01

The investigation of the association of the climate variables with hip fracture incidences is important in social health issues. This study examined and modeled the seasonal variation of monthly population based hip fracture rate (HFr) time series. The seasonal ARIMA time series modeling approach is used to model monthly HFr incidences time series of female and male patients of the ages 40-74 and 75+ of Montreal, Québec province, Canada, in the period of 1993-2004. The correlation coefficients between meteorological variables such as temperature, snow depth, rainfall depth and day length and HFr are significant. The nonparametric Mann-Kendall test for trend assessment and the nonparametric Levene's test and Wilcoxon's test for checking the difference of HFr before and after change point are also used. The seasonality in HFr indicated sharp difference between winter and summer time. The trend assessment showed decreasing trends in HFr of female and male groups. The nonparametric test also indicated a significant change of the mean HFr. A seasonal ARIMA model was applied for HFr time series without trend and a time trend ARIMA model (TT-ARIMA) was developed and fitted to HFr time series with a significant trend. The multi criteria evaluation showed the adequacy of SARIMA and TT-ARIMA models for modeling seasonal hip fracture time series with and without significant trend. In the time series analysis of HFr of the Montreal region, the effects of the seasonal variation of climate variables on hip fracture are clear. The Seasonal ARIMA model is useful for modeling HFr time series without trend. However, for time series with significant trend, the TT-ARIMA model should be applied for modeling HFr time series. Copyright © 2011 Elsevier Inc. All rights reserved.

An artificial neural network improves prediction of observed survival in patients with laryngeal squamous carcinoma.

PubMed

Jones, Andrew S; Taktak, Azzam G F; Helliwell, Timothy R; Fenton, John E; Birchall, Martin A; Husband, David J; Fisher, Anthony C

2006-06-01

The accepted method of modelling and predicting failure/survival, Cox's proportional hazards model, is theoretically inferior to neural network derived models for analysing highly complex systems with large datasets. A blinded comparison of the neural network versus the Cox's model in predicting survival utilising data from 873 treated patients with laryngeal cancer. These were divided randomly and equally into a training set and a study set and Cox's and neural network models applied in turn. Data were then divided into seven sets of binary covariates and the analysis repeated. Overall survival was not significantly different on Kaplan-Meier plot, or with either test model. Although the network produced qualitatively similar results to Cox's model it was significantly more sensitive to differences in survival curves for age and N stage. We propose that neural networks are capable of prediction in systems involving complex interactions between variables and non-linearity.

Comparative in vitro flow study of 3 different Ex-PRESS miniature glaucoma device models.

PubMed

Estermann, Stephan; Yuttitham, Kanokwan; Chen, Julie A; Lee, On-Tat; Stamper, Robert L

2013-03-01

To determine the flow characteristics of the 3 different models of the Ex-PRESS miniature glaucoma device in a controlled laboratory study. The 3 different Ex-PRESS models (P-50, R-50, and P-200; Optonol Ltd; now Alcon Lab) were tested using a gravity-driven flow test. Three samples of each of the 3 Ex-PRESS models were subjected to a constant gravitational force of fluid at 5 different pressure levels (5 to 25 mm Hg). Four measurements per sample were taken at each pressure level. The main outcome measure was flow rate (Q) (µL/min). Resistance (R) was calculated by dividing pressure (P) by the measured flow (Q). The flow rate was primarily pressure dependent. The P-200 model (internal diameter 200 µm) showed a statistically significant higher flow rate and lower resistance compared with both the P-50 and R-50 models (internal diameter 50 µm) (P<0.0001). The P-50 and R-50 models demonstrated similar flow rates (P=0.08) despite their difference in tube length (2.64 vs. 2.94 mm). The 3 models of the Ex-PRESS mini shunt behaved in vitro as simple flow resistors by creating a relatively constant resistance to flow. Tube diameter was the only parameter with significant impact on flow and resistance. All models demonstrated flow rates per unit of pressure much higher than the outflow facility of a healthy human eye.

Understanding eye movements in face recognition using hidden Markov models.

PubMed

Chuk, Tim; Chan, Antoni B; Hsiao, Janet H

2014-09-16

We use a hidden Markov model (HMM) based approach to analyze eye movement data in face recognition. HMMs are statistical models that are specialized in handling time-series data. We conducted a face recognition task with Asian participants, and model each participant's eye movement pattern with an HMM, which summarized the participant's scan paths in face recognition with both regions of interest and the transition probabilities among them. By clustering these HMMs, we showed that participants' eye movements could be categorized into holistic or analytic patterns, demonstrating significant individual differences even within the same culture. Participants with the analytic pattern had longer response times, but did not differ significantly in recognition accuracy from those with the holistic pattern. We also found that correct and wrong recognitions were associated with distinctive eye movement patterns; the difference between the two patterns lies in the transitions rather than locations of the fixations alone. © 2014 ARVO.

Open ocean tide modelling

NASA Technical Reports Server (NTRS)

Parke, M. E.

1978-01-01

Two trends evident in global tidal modelling since the first GEOP conference in 1972 are described. The first centers on the incorporation of terms for ocean loading and gravitational self attraction into Laplace's tidal equations. The second centers on a better understanding of the problem of near resonant modelling and the need for realistic maps of tidal elevation for use by geodesists and geophysicists. Although new models still show significant differences, especially in the South Atlantic, there are significant similarities in many of the world's oceans. This allows suggestions to be made for future locations for bottom pressure gauge measurements. Where available, estimates of M2 tidal dissipation from the new models are significantly lower than estimates from previous models.

[Effect of algorithms for calibration set selection on quantitatively determining asiaticoside content in Centella total glucosides by near infrared spectroscopy].

PubMed

Zhan, Xue-yan; Zhao, Na; Lin, Zhao-zhou; Wu, Zhi-sheng; Yuan, Rui-juan; Qiao, Yan-jiang

2014-12-01

The appropriate algorithm for calibration set selection was one of the key technologies for a good NIR quantitative model. There are different algorithms for calibration set selection, such as Random Sampling (RS) algorithm, Conventional Selection (CS) algorithm, Kennard-Stone(KS) algorithm and Sample set Portioning based on joint x-y distance (SPXY) algorithm, et al. However, there lack systematic comparisons between two algorithms of the above algorithms. The NIR quantitative models to determine the asiaticoside content in Centella total glucosides were established in the present paper, of which 7 indexes were classified and selected, and the effects of CS algorithm, KS algorithm and SPXY algorithm for calibration set selection on the accuracy and robustness of NIR quantitative models were investigated. The accuracy indexes of NIR quantitative models with calibration set selected by SPXY algorithm were significantly different from that with calibration set selected by CS algorithm or KS algorithm, while the robustness indexes, such as RMSECV and |RMSEP-RMSEC|, were not significantly different. Therefore, SPXY algorithm for calibration set selection could improve the predicative accuracy of NIR quantitative models to determine asiaticoside content in Centella total glucosides, and have no significant effect on the robustness of the models, which provides a reference to determine the appropriate algorithm for calibration set selection when NIR quantitative models are established for the solid system of traditional Chinese medcine.

Differences in radial expansion force among inferior vena cava filter models support documented perforation rates.

PubMed

Robins, J Eli; Ragai, Ihab; Yamaguchi, Dean J

2018-05-01

Inferior vena cava (IVC) filters are used in patients at risk for pulmonary embolism who cannot be anticoagulated. Unfortunately, these filters are not without risk, and complications include perforation, migration, and filter fracture. The most prevalent complication is filter perforation of the IVC, with incidence varying among filter models. To our knowledge, the mechanical properties of IVC filters have not been evaluated and are not readily available through the manufacturer. This study sought to determine whether differences in mechanical properties are similar to differences in documented perforation rates. The radial expansion forces of Greenfield (Boston Scientific, Marlborough, Mass), Cook Celect (Cook Medical, Bloomington, Ind), and Cook Platinum filters were analyzed with three replicates per group. The intrinsic force exerted by the filter on the measuring device was collected in real time during controlled expansion. Replicates were averaged and significance was determined by calculating analysis of covariance using SAS software (SAS Institute, Cary, NC). Each filter model generated a significantly different radial expansion force (P < .001), and force was distributed at significantly different rates (P < .001) during expansion. The largest radial expansion force at minimal caval diameter was seen in the Cook Platinum filter, followed by the Cook Celect and Greenfield filters. Radial force dispersion during expansion was greatest in the Cook Celect, followed by the Cook Platinum and Greenfield filters. Differences in radial expansion forces among IVC filter models are consistent with documented perforation rates. Cook Celect IVC filters have a higher incidence of perforation compared with Greenfield filters when they are left in place for >90 days. Evaluation of Cook Celect filters yielded a significantly higher radial expansion force at minimum caval diameter, with greater force dispersion during expansion. Copyright © 2018 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

Population Pharmacokinetics of Intranasal Scopolamine

NASA Technical Reports Server (NTRS)

Wu, L.; Chow, D. S. L.; Putcha, L.

2013-01-01

Introduction: An intranasal gel dosage formulation of scopolamine (INSCOP) was developed for the treatment of Space Motion Sickness (SMS).The bioavailability and pharmacokinetics (PK) was evaluated using data collected in Phase II IND protocols. We reported earlier statistically significant gender differences in PK parameters of INSCOP at a dose level of 0.4 mg. To identify covariates that influence PK parameters of INSCOP, we examined population covariates of INSCOP PK model for 0.4 mg dose. Methods: Plasma scopolamine concentrations versus time data were collected from 20 normal healthy human subjects (11 male/9 female) after a 0.4 mg dose. Phoenix NLME was employed for PK analysis of these data using gender, body weight and age as covariates for model selection. Model selection was based on a likelihood ratio test on the difference of criteria (-2LL). Statistical significance for base model building and individual covariate analysis was set at P less than 0.05{delta(-2LL)=3.84}. Results: A one-compartment pharmacokinetic model with first-order elimination best described INSCOP concentration ]time profiles. Inclusion of gender, body weight and age as covariates individually significantly reduced -2LL by the cut-off value of 3.84(P less than 0.05) when tested against the base model. After the forward stepwise selection and backward elimination steps, gender was selected to add to the final model which had significant influence on absorption rate constant (ka) and the volume of distribution (V) of INSCOP. Conclusion: A population pharmacokinetic model for INSCOP has been identified and gender was a significant contributing covariate for the final model. The volume of distribution and Ka were significantly higher in males than in females which confirm gender-dependent pharmacokinetics of scopolamine after administration of a 0.4 mg dose.

Accuracy of digital models generated by conventional impression/plaster-model methods and intraoral scanning.

PubMed

Tomita, Yuki; Uechi, Jun; Konno, Masahiro; Sasamoto, Saera; Iijima, Masahiro; Mizoguchi, Itaru

2018-04-17

We compared the accuracy of digital models generated by desktop-scanning of conventional impression/plaster models versus intraoral scanning. Eight ceramic spheres were attached to the buccal molar regions of dental epoxy models, and reference linear-distance measurement were determined using a contact-type coordinate measuring instrument. Alginate (AI group) and silicone (SI group) impressions were taken and converted into cast models using dental stone; the models were scanned using desktop scanner. As an alternative, intraoral scans were taken using an intraoral scanner, and digital models were generated from these scans (IOS group). Twelve linear-distance measurement combinations were calculated between different sphere-centers for all digital models. There were no significant differences among the three groups using total of six linear-distance measurements. When limited to five lineardistance measurement, the IOS group showed significantly higher accuracy compared to the AI and SI groups. Intraoral scans may be more accurate compared to scans of conventional impression/plaster models.

Effectiveness of School Counselor Supervision with Trainees Utilizing the ASCA Model

ERIC Educational Resources Information Center

Blakely, Colette; Underwood, Lee A.; Rehfuss, Mark

2009-01-01

This study sought to determine if differences existed in the supervision of school counselors in traditional school counseling programs versus Recognized ASCA Model Programs (RAMP). The findings indicated that there are significant differences between traditional counseling supervisors and RAMP counseling supervisors across all supervisory…

Lack of species-specific difference in pulmonary function when using mouse versus human plasma in a mouse model of hemorrhagic shock.

PubMed

Peng, Zhanglong; Pati, Shibani; Fontaine, Magali J; Hall, Kelly; Herrera, Anthony V; Kozar, Rosemary A

2016-11-01

Clinical studies have demonstrated that the early and empiric use of plasma improves survival after hemorrhagic shock. We have demonstrated in rodent models of hemorrhagic shock that resuscitation with plasma is protective to the lungs compared with lactated Ringer's solution. As our long-term objective is to determine the molecular mechanisms that modulate plasma's protective effects in injured bleeding patients, we have used human plasma in a mouse model of hemorrhagic shock. The goal of the current experiments is to determine if there are significant adverse effects on lung injury when using human versus mouse plasma in an established murine model of hemorrhagic shock and laparotomy. Mice underwent laparotomy and 90 minutes of hemorrhagic shock to a mean arterial pressure (MAP) of 35 ± 5 mm Hg followed by resuscitation at 1× shed blood using either mouse fresh frozen plasma (FFP), human FFP, or human lyophilized plasma. Mean arterial pressure was recorded during shock and for the first 30 minutes of resuscitation. After 3 hours, animals were killed, and lungs collected for analysis. There was a significant increase in early MAP when mouse FFP was used to resuscitate animals compared with human FFP or human lyophilized plasma. However, despite these differences, analysis of the mouse lungs revealed no significant differences in pulmonary histopathology, lung permeability, or lung edema between all three plasma groups. Analysis of neutrophil infiltration in the lungs revealed that mouse FFP decreased neutrophil influx as measured by neutrophil staining; however, myeloperoxidase immunostaining revealed no significant differences in between groups. The study of human plasma in a mouse model of hemorrhagic shock is feasible but does reveal some differences compared with mouse plasma-based resuscitation in physiologic measures such as MAP postresuscitation. Measures of end organ function such as lung injury appear to be comparable in this acute model of hemorrhagic shock and resuscitation.

Comparison of 5 Different Rat Models to Establish a Standard Animal Model for Research Into Interstitial Cystitis.

PubMed

Song, Phil Hyun; Chun, So Young; Chung, Jae-Wook; Kim, Yeon Yong; Lee, Hyo Jung; Lee, Jun Nyung; Ha, Yun-Sok; Yoo, Eun Sang; Kwon, Tae Gyun; Kim, Jeongshik; Kim, Dae Hwan; Kim, Bum Soo

2017-09-01

We evaluated 5 different rat models using different agents in order to establish a standard animal model for interstitial cystitis (IC) in terms of the functional and pathologic characteristics of the bladder. Five IC models were generated in 8-week-old female Sprague-Dawley rats via transurethral instillation of 0.1M hydrogen chloride (HCl) or 3% acetic acid (AA), intraperitoneal injection of cyclophosphamide (CYP) or lipopolysaccharide (LPS), or subcutaneous injection of uroplakin II (UPK2). After generating the IC models, conscious cystometry was performed on days 3, 7, and 14. All rats were euthanized on day 14 and their bladders were obtained for histological and pro-inflammatory-related gene expression analysis. In the cystometric analysis, all experimental groups showed significantly decreased intercontraction intervals compared with the control group on day 3, but only the LPS and UPK groups maintained significantly shorter intercontraction intervals than the control group on day 14. The histological analysis revealed that areas with severe urothelial erosion (HCl, AA, and UPK) and hyperplasia (CYP and LPS), particularly in the UPK-treated bladders, showed a markedly increased infiltration of toluidine blue-stained mast cells and increased tissue fibrosis. In addition, significantly elevated expression of interleukin-1b, interleukin-6, myeloperoxidase, monocyte chemotactic protein 1, and Toll-like receptors 2 and 4 was observed in the UPK group compared to the other groups. Among the 5 different agents, the injection of UPK generated the most effective IC animal model, showing consequent urothelial barrier loss, inflammatory reaction, tissue fibrosis stimulation, and persistent hyperactive bladder.

Identifying student mental models from their response pattern to a physics multiple-choice test

NASA Astrophysics Data System (ADS)

Montenegro Maggio, Maximiliano Jose

Previous work has shown that students present different misconceptions across different but similar physical situations, but the cause of these differences is still not clear. In this study, a novel analysis method was introduced to help to gain a better understanding of how different physical situations affect students' responses and learning. This novel analysis groups students into mental model groups (MMG) by similarities in their responses to multiple-choice test items, under the assumption that they have similar mental models. The Mass and Energy Conservation test was developed to probe the common misconception that objects with greater mass fall faster than objects with lesser mass across four physical situations and four knowledge sub-domains: information, dynamics, work, and energy. The test was applied before and after energy instruction to 144 college students in a large Midwestern university attending a calculus-based introductory physics course. Test time along with instruction and physical situation were the two factors. It was found that physical situation did not have a significant effect on mental models: The number of MMGs identified and the fraction of students belonging to the same MMG were not significantly different (p > .05) across physical situations. However, there was a significant effect of test time on mental models (p < .05): the fraction of students belonging to the same MMG changed from the pretest to the posttest, in that the MMG representing higher performance became predominant than the MMG with lower performance for the posttest results. A MANOVA for the average scores for each sub-domain and physical situation combination was applied to validate the previous results. It was found that a significant effect (p < .01) by physical situation resulted due to a lower average dynamics sub-domain score for the friction physical-situation attribute when compared to the no-friction physical-situation attribute. A significant effect (p < .01) was found for test time. This was due to an increase of the average energy sub-domain score from the pretest to the posttest. No significant interaction effect ( p > .05) was found. The MANOVA results obtained can be explained through the change in proportion of the MMGs present in the sample.

Asymmetric warming significantly affects net primary production, but not ecosystem carbon balances of forest and grassland ecosystems in northern China

NASA Astrophysics Data System (ADS)

Su, Hongxin; Feng, Jinchao; Axmacher, Jan C.; Sang, Weiguo

2015-03-01

We combine the process-based ecosystem model (Biome-BGC) with climate change-scenarios based on both RegCM3 model outputs and historic observed trends to quantify differential effects of symmetric and asymmetric warming on ecosystem net primary productivity (NPP), heterotrophic respiration (Rh) and net ecosystem productivity (NEP) of six ecosystem types representing different climatic zones of northern China. Analysis of covariance shows that NPP is significant greater at most ecosystems under the various environmental change scenarios once temperature asymmetries are taken into consideration. However, these differences do not lead to significant differences in NEP, which indicates that asymmetry in climate change does not result in significant alterations of the overall carbon balance in the dominating forest or grassland ecosystems. Overall, NPP, Rh and NEP are regulated by highly interrelated effects of increases in temperature and atmospheric CO2 concentrations and precipitation changes, while the magnitude of these effects strongly varies across the six sites. Further studies underpinned by suitable experiments are nonetheless required to further improve the performance of ecosystem models and confirm the validity of these model predictions. This is crucial for a sound understanding of the mechanisms controlling the variability in asymmetric warming effects on ecosystem structure and functioning.

Asymmetric warming significantly affects net primary production, but not ecosystem carbon balances of forest and grassland ecosystems in northern China.

PubMed

Su, Hongxin; Feng, Jinchao; Axmacher, Jan C; Sang, Weiguo

2015-03-13

We combine the process-based ecosystem model (Biome-BGC) with climate change-scenarios based on both RegCM3 model outputs and historic observed trends to quantify differential effects of symmetric and asymmetric warming on ecosystem net primary productivity (NPP), heterotrophic respiration (Rh) and net ecosystem productivity (NEP) of six ecosystem types representing different climatic zones of northern China. Analysis of covariance shows that NPP is significant greater at most ecosystems under the various environmental change scenarios once temperature asymmetries are taken into consideration. However, these differences do not lead to significant differences in NEP, which indicates that asymmetry in climate change does not result in significant alterations of the overall carbon balance in the dominating forest or grassland ecosystems. Overall, NPP, Rh and NEP are regulated by highly interrelated effects of increases in temperature and atmospheric CO2 concentrations and precipitation changes, while the magnitude of these effects strongly varies across the six sites. Further studies underpinned by suitable experiments are nonetheless required to further improve the performance of ecosystem models and confirm the validity of these model predictions. This is crucial for a sound understanding of the mechanisms controlling the variability in asymmetric warming effects on ecosystem structure and functioning.

Asymmetric warming significantly affects net primary production, but not ecosystem carbon balances of forest and grassland ecosystems in northern China

PubMed Central

Su, Hongxin; Feng, Jinchao; Axmacher, Jan C.; Sang, Weiguo

2015-01-01

We combine the process-based ecosystem model (Biome-BGC) with climate change-scenarios based on both RegCM3 model outputs and historic observed trends to quantify differential effects of symmetric and asymmetric warming on ecosystem net primary productivity (NPP), heterotrophic respiration (Rh) and net ecosystem productivity (NEP) of six ecosystem types representing different climatic zones of northern China. Analysis of covariance shows that NPP is significant greater at most ecosystems under the various environmental change scenarios once temperature asymmetries are taken into consideration. However, these differences do not lead to significant differences in NEP, which indicates that asymmetry in climate change does not result in significant alterations of the overall carbon balance in the dominating forest or grassland ecosystems. Overall, NPP, Rh and NEP are regulated by highly interrelated effects of increases in temperature and atmospheric CO2 concentrations and precipitation changes, while the magnitude of these effects strongly varies across the six sites. Further studies underpinned by suitable experiments are nonetheless required to further improve the performance of ecosystem models and confirm the validity of these model predictions. This is crucial for a sound understanding of the mechanisms controlling the variability in asymmetric warming effects on ecosystem structure and functioning. PMID:25766381

Scoring of Decomposition: A Proposed Amendment to the Method When Using a Pig Model for Human Studies.

PubMed

Keough, Natalie; Myburgh, Jolandie; Steyn, Maryna

2017-07-01

Decomposition studies often use pigs as proxies for human cadavers. However, differences in decomposition sequences/rates relative to humans have not been scientifically examined. Descriptions of five main decomposition stages (humans) were developed and refined by Galloway and later by Megyesi. However, whether these changes/processes are alike in pigs is unclear. Any differences can have significant effects when pig models are used for human PMI estimation. This study compared human decomposition models to the changes observed in pigs. Twenty pigs (50-90 kg) were decomposed over five months and decompositional features recorded. Total body scores (TBS) were calculated. Significant differences were observed during early decomposition between pigs and humans. An amended scoring system to be used in future studies was developed. Standards for PMI estimation derived from porcine models may not directly apply to humans and may need adjustment. Porcine models, however, remain valuable to study variables influencing decomposition. © 2016 American Academy of Forensic Sciences.

Relating Derived Relations as a Model of Analogical Reasoning: Reaction Times and Event-Related Potentials

PubMed Central

Barnes-Holmes, Dermot; Regan, Donal; Barnes-Holmes, Yvonne; Commins, Sean; Walsh, Derek; Stewart, Ian; Smeets, Paul M; Whelan, Robert; Dymond, Simon

2005-01-01

The current study aimed to test a Relational Frame Theory (RFT) model of analogical reasoning based on the relating of derived same and derived difference relations. Experiment 1 recorded reaction time measures of similar–similar (e.g., “apple is to orange as dog is to cat”) versus different–different (e.g., “he is to his brother as chalk is to cheese”) derived relational responding, in both speed-contingent and speed-noncontingent conditions. Experiment 2 examined the event-related potentials (ERPs) associated with these two response patterns. Both experiments showed similar–similar responding to be significantly faster than different–different responding. Experiment 2 revealed significant differences between the waveforms of the two response patterns in the left-hemispheric prefrontal regions; different–different waveforms were significantly more negative than similar–similar waveforms. The behavioral and neurophysiological data support the RFT prediction that, all things being equal, similar–similar responding is relationally “simpler” than, and functionally distinct from, different–different analogical responding. The ERP data were fully consistent with findings in the neurocognitive literature on analogy. These findings strengthen the validity of the RFT model of analogical reasoning and supplement the behavior-analytic approach to analogy based on the relating of derived relations. PMID:16596974

Nonlocal optical effects on the Goos-Hänchen shift at an interface of a composite material of metallic nanoparticles.

PubMed

Huang, J H; Leung, P T

2013-07-01

We present a theoretical study on the nonlocal optical effects on the Goos-Hänchen (GH) shift of reflected light from a composite material of metallic nanoparticles (MNPs). Using different nonlocal effective medium models, it is observed that such effects can be significant for small MNP of sizes down to a few nanometers. For small metallic volume fractions, the composite behaves like dielectric and the nonlocal effects lead to significant different Brewster angles, at which large negative GH shifts take place. For larger volume fractions or shorter wavelengths, the composite behaves more like metals and the nonlocal effects also lead to different Brewster angles but at values close to grazing incidence. These results will have significant implications in the application of different effective medium models for the characterization of these nanometallic composites when the MNPs are down to a few nanometers in size.

Significance testing of clinical data using virus dynamics models with a Markov chain Monte Carlo method: application to emergence of lamivudine-resistant hepatitis B virus.

PubMed Central

Burroughs, N J; Pillay, D; Mutimer, D

1999-01-01

Bayesian analysis using a virus dynamics model is demonstrated to facilitate hypothesis testing of patterns in clinical time-series. Our Markov chain Monte Carlo implementation demonstrates that the viraemia time-series observed in two sets of hepatitis B patients on antiviral (lamivudine) therapy, chronic carriers and liver transplant patients, are significantly different, overcoming clinical trial design differences that question the validity of non-parametric tests. We show that lamivudine-resistant mutants grow faster in transplant patients than in chronic carriers, which probably explains the differences in emergence times and failure rates between these two sets of patients. Incorporation of dynamic models into Bayesian parameter analysis is of general applicability in medical statistics. PMID:10643081

Comparison of analytical models for zonal flow generation in ion-temperature-gradient mode turbulence

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

Anderson, J.; Miki, K.; Uzawa, K.

2006-11-30

During the past years the understanding of the multi scale interaction problems have increased significantly. However, at present there exists a flora of different analytical models for investigating multi scale interactions and hardly any specific comparisons have been performed among these models. In this work two different models for the generation of zonal flows from ion-temperature-gradient (ITG) background turbulence are discussed and compared. The methods used are the coherent mode coupling model and the wave kinetic equation model (WKE). It is shown that the two models give qualitatively the same results even though the assumption on the spectral difference ismore » used in the (WKE) approach.« less

Association of long-term PM2.5 exposure with mortality using different air pollution exposure models: impacts in rural and urban California.

PubMed

Garcia, Cynthia A; Yap, Poh-Sin; Park, Hye-Youn; Weller, Barbara L

2016-01-01

Most PM2.5-associated mortality studies are not conducted in rural areas where mortality rates may differ when population characteristics, health care access, and PM2.5 composition differ. PM2.5-associated mortality was investigated in the elderly residing in rural-urban zip codes. Exposure (2000-2006) was estimated using different models and Poisson regression was performed using 2006 mortality data. PM2.5 models estimated comparable exposures, although subtle differences were observed in rate ratios (RR) within areas by health outcomes. Cardiovascular disease (CVD), ischemic heart disease (IHD), and cardiopulmonary disease (CPD), mortality was significantly associated with rural, urban, and statewide chronic PM2.5 exposures. We observed larger effect sizes in RRs for CVD, CPD, and all-cause (AC) with similar sizes for IHD mortality in rural areas compared to urban areas. PM2.5 was significantly associated with AC mortality in rural areas and statewide; however, in urban areas, only the most restrictive exposure model showed an association. Given the results seen, future mortality studies should consider adjusting for differences with rural-urban variables.

Light Scattering by Gaussian Particles: A Solution with Finite-Difference Time Domain Technique

NASA Technical Reports Server (NTRS)

Sun, W.; Nousiainen, T.; Fu, Q.; Loeb, N. G.; Videen, G.; Muinonen, K.

2003-01-01

The understanding of single-scattering properties of complex ice crystals has significance in atmospheric radiative transfer and remote-sensing applications. In this work, light scattering by irregularly shaped Gaussian ice crystals is studied with the finite-difference time-domain (FDTD) technique. For given sample particle shapes and size parameters in the resonance region, the scattering phase matrices and asymmetry factors are calculated. It is found that the deformation of the particle surface can significantly smooth the scattering phase functions and slightly reduce the asymmetry factors. The polarization properties of irregular ice crystals are also significantly different from those of spherical cloud particles. These FDTD results could provide a reference for approximate light-scattering models developed for irregular particle shapes and can have potential applications in developing a much simpler practical light scattering model for ice clouds angular-distribution models and for remote sensing of ice clouds and aerosols using polarized light. (copyright) 2003 Elsevier Science Ltd. All rights reserved.

Birth order in small multihospital systems.

PubMed

Luke, R D; Ozcan, Y A; Begun, J W

1990-06-01

The strategic behaviors of small multihospital systems have received little attention in the literature despite the fact that small systems are the predominant scale among multihospital systems. This study examines one important aspect of small-system strategic behaviors: the birth-order or evolutionary patterns of hospital acquisition. The evolutionary patterns of acquisition are compared across three strategic model types studied elsewhere: local market, investment, and historical. Using data obtained from a variety of sources, local market model systems are found, in the sequence of acquisition, to be significantly different from the other two model types in terms of relative distances of acquisitions from the initiating or parent hospital, the sizes of acquisition hospitals, the complexity of those hospitals, and the likelihood that the acquisitions are located in rural areas. Differences between parents and acquisitions are also significant, as hypothesized, for the market model system types, although they are not generally significant for the other two model types. The findings suggest that the market model represents an important strategic form that may have important implications for the restructuring of hospital markets.

Non-invasive brain stimulation and computational models in post-stroke aphasic patients: single session of transcranial magnetic stimulation and transcranial direct current stimulation. A randomized clinical trial.

PubMed

Santos, Michele Devido Dos; Cavenaghi, Vitor Breseghello; Mac-Kay, Ana Paula Machado Goyano; Serafim, Vitor; Venturi, Alexandre; Truong, Dennis Quangvinh; Huang, Yu; Boggio, Paulo Sérgio; Fregni, Felipe; Simis, Marcel; Bikson, Marom; Gagliardi, Rubens José

2017-01-01

Patients undergoing the same neuromodulation protocol may present different responses. Computational models may help in understanding such differences. The aims of this study were, firstly, to compare the performance of aphasic patients in naming tasks before and after one session of transcranial direct current stimulation (tDCS), transcranial magnetic stimulation (TMS) and sham, and analyze the results between these neuromodulation techniques; and secondly, through computational model on the cortex and surrounding tissues, to assess current flow distribution and responses among patients who received tDCS and presented different levels of results from naming tasks. Prospective, descriptive, qualitative and quantitative, double blind, randomized and placebo-controlled study conducted at Faculdade de Ciências Médicas da Santa Casa de São Paulo. Patients with aphasia received one session of tDCS, TMS or sham stimulation. The time taken to name pictures and the response time were evaluated before and after neuromodulation. Selected patients from the first intervention underwent a computational model stimulation procedure that simulated tDCS. The results did not indicate any statistically significant differences from before to after the stimulation.The computational models showed different current flow distributions. The present study did not show any statistically significant difference between tDCS, TMS and sham stimulation regarding naming tasks. The patients'responses to the computational model showed different patterns of current distribution.

Assessment of nasal spray deposition pattern in a silicone human nose model using a color-based method.

PubMed

Kundoor, Vipra; Dalby, Richard N

2010-01-01

To develop a simple and inexpensive method to visualize and quantify droplet deposition patterns. Deposition pattern was determined by uniformly coating the nose model with Sar-Gel (a paste that changes from white to purple on contact with water) and subsequently discharging sprays into the nose model. The color change was captured using a digital camera and analyzed using Adobe Photoshop. Several tests were conducted to validate the method. Deposition patterns of different nasal sprays (Ayr, Afrin, and Zicam) and different nasal drug delivery devices (Afrin nasal spray and PARI Sinustar nasal nebulizer) were compared. We also used the method to evaluate the effect of inhaled flow rate on nasal spray deposition. There was a significant difference in the deposition area for Ayr, Afrin, and Zicam. The deposition areas of Afrin nasal spray and PARI Sinustar nasal nebulizer (2 min and 5 min) were significantly different. Inhaled flow rate did not have a significant effect on the deposition pattern. Lower viscosity formulations (Ayr, Afrin) provided greater coverage than the higher viscosity formulation (Zicam). The nebulizer covered a greater surface area than the spray pump we evaluated. Aerosol deposition in the nose model was not affected by air flow conditions.

Ecosystem Model Performance at Wetlands: Results from the North American Carbon Program Site Synthesis

NASA Astrophysics Data System (ADS)

Sulman, B. N.; Desai, A. R.; Schroeder, N. M.; NACP Site Synthesis Participants

2011-12-01

Northern peatlands contain a significant fraction of the global carbon pool, and their responses to hydrological change are likely to be important factors in future carbon cycle-climate feedbacks. Global-scale carbon cycle modeling studies typically use general ecosystem models with coarse spatial resolution, often without peatland-specific processes. Here, seven ecosystem models were used to simulate CO2 fluxes at three field sites in Canada and the northern United States, including two nutrient-rich fens and one nutrient-poor, sphagnum-dominated bog, from 2002-2006. Flux residuals (simulated - observed) were positively correlated with measured water table for both gross ecosystem productivity (GEP) and ecosystem respiration (ER) at the two fen sites for all models, and were positively correlated with water table at the bog site for the majority of models. Modeled diurnal cycles at fen sites agreed well with eddy covariance measurements overall. Eddy covariance GEP and ER were higher during dry periods than during wet periods, while model results predicted either the opposite relationship or no significant difference. At the bog site, eddy covariance GEP had no significant dependence on water table, while models predicted higher GEP during wet periods. All models significantly over-estimated GEP at the bog site, and all but one over-estimated ER at the bog site. Carbon cycle models in peatland-rich regions could be improved by incorporating better models or measurements of hydrology and by inhibiting GEP and ER rates under saturated conditions. Bogs and fens likely require distinct treatments in ecosystem models due to differences in nutrients, peat properties, and plant communities.

Effect of insurance parity on substance abuse treatment.

PubMed

Azzone, Vanessa; Frank, Richard G; Normand, Sharon-Lise T; Burnam, M Audrey

2011-02-01

This study examined the impact of insurance parity on the use, cost, and quality of substance abuse treatment. The authors compared substance abuse treatment spending and utilization from 1999 to 2002 for continuously enrolled beneficiaries covered by Federal Employees Health Benefit (FEHB) plans, which require parity coverage of mental health and substance use disorders, with spending and utilization among beneficiaries in a matched set of health plans without parity coverage. Logistic regression models estimated the probability of any substance abuse service use. Conditional on use, linear models estimated total and out-of-pocket spending. Logistic regression models for three quality indicators for substance abuse treatment were also estimated: identification of adult enrollees with a new substance abuse diagnosis, treatment initiation, and treatment engagement. Difference-in-difference estimates were computed as (postparity - preparity) differences in outcomes in plans without parity subtracted from those in FEHB plans. There were no significant differences between FEHB and non-FEHB plans in rates of change in average utilization of substance abuse services. Conditional on service utilization, the rate of substance abuse treatment out-of-pocket spending declined significantly in the FEHB plans compared with the non-FEHB plans (mean difference=-$101.09, 95% confidence interval [CI]=-$198.06 to -$4.12), whereas changes in total plan spending per user did not differ significantly. With parity, more patients had new diagnoses of a substance use disorder (difference-in-difference risk=.10%, CI=.02% to .19%). No statistically significant differences were found for rates of initiation and engagement in substance abuse treatment. Findings suggest that for continuously enrolled populations, providing parity of substance abuse treatment coverage improved insurance protection but had little impact on utilization, costs for plans, or quality of care.

Condylar position analysis with a new electronic condylar position measuring instrument E-CPM: influence of different examiners and a working bite on reproducibility.

PubMed

Vahle-Hinz, K; Rybczynski, A; Jakstat, H; Ahlers, M O

2009-01-01

Condylar position analysis facilitates a quantitative comparison of the condylar position with and without a bite record, different records and changed influencing factors. Handling by the examiner when positioning the model is a significant factor with regard to the accuracy of the examination. Measurement accuracy could be improved when positioning the models by using special working bites, hence the objective of the experiments described in this study consisted in examining the extent to which the measuring results are influenced by different examiners and by using working bites. In the first trial, one examiner performed ten measurements without and with an interposed working bite for five model pairs in each case. In the second trial, nine examiners (three specialized dentists, three dental assistants, three students) performed ten measurements in each case without and with an interposed working bite. The three-dimensional position was read digitally with the E-CPM (Gamma Dental, Klosterneuburg/Vienna, Austria), recorded by means of spreadsheet software (Microsoft Excel) and diagnostic software (CMDfact, CMD3D module, dentaConcept, Hamburg), and evaluated with graphing software (Sigma Plot, Systat Software, USA). In the first trial, it was shown that the reproducibility of mounting was improved markedly (p <0.01) by using bite records in the form of working bites. In the second trial, it was shown that the mean error increased significantly (p <0.01) when several examiners performed the measurements compared with the results of one examiner alone. No significantly different results occurred (p < 0.01) in the comparison of the different groups of examiners with different educational and training backgrounds. This applied for the mounting methods without and with working bite. On the other hand, the reproducibility of mounting improved distinctly (p<0.01) in every group of examiners when working bites were used. Reproducibility of condylar position analysis was improved significantly by mounting the models with special working bites. This applied for operators of different professional background (dentists, dental assistants and dental students), while there were no significant differences between results of the three groups.

A review of unmanned aircraft system ground risk models

NASA Astrophysics Data System (ADS)

Washington, Achim; Clothier, Reece A.; Silva, Jose

2017-11-01

There is much effort being directed towards the development of safety regulations for unmanned aircraft systems (UAS). National airworthiness authorities have advocated the adoption of a risk-based approach, whereby regulations are driven by the outcomes of a systematic process to assess and manage identified safety risks. Subsequently, models characterising the primary hazards associated with UAS operations have now become critical to the development of regulations and in turn, to the future of the industry. Key to the development of airworthiness regulations for UAS is a comprehensive understanding of the risks UAS operations pose to people and property on the ground. A comprehensive review of the literature identified 33 different models (and component sub models) used to estimate ground risk posed by UAS. These models comprise failure, impact location, recovery, stress, exposure, incident stress and harm sub-models. The underlying assumptions and treatment of uncertainties in each of these sub-models differ significantly between models, which can have a significant impact on the development of regulations. This paper reviews the state-of-the-art in research into UAS ground risk modelling, discusses how the various sub-models relate to the different components of the regulation, and explores how model-uncertainties potentially impact the development of regulations for UAS.

A data-centric approach to understanding the pricing of financial options

NASA Astrophysics Data System (ADS)

Healy, J.; Dixon, M.; Read, B.; Cai, F. F.

2002-05-01

We investigate what can be learned from a purely phenomenological study of options prices without modelling assumptions. We fitted neural net (NN) models to LIFFE ``ESX'' European style FTSE 100 index options using daily data from 1992 to 1997. These non-parametric models reproduce the Black-Scholes (BS) analytic model in terms of fit and performance measures using just the usual five inputs (S, X, t, r, IV). We found that adding transaction costs (bid-ask spread) to these standard five parameters gives a comparable fit and performance. Tests show that the bid-ask spread can be a statistically significant explanatory variable for option prices. The difference in option prices between the models with transaction costs and those without ranges from about -3.0 to +1.5 index points, varying with maturity date. However, the difference depends on the moneyness (S/X), being greatest in-the-money. This suggests that use of a five-factor model can result in a pricing difference of up to #10 to #30 per call option contract compared with modelling under transaction costs. We found that the influence of transaction costs varied between different yearly subsets of the data. Open interest is also a significant explanatory variable, but volume is not.

The Impact of Noninvariant Intercepts in Latent Means Models

ERIC Educational Resources Information Center

Whittaker, Tiffany A.

2013-01-01

Latent means methods such as multiple-indicator multiple-cause (MIMIC) and structured means modeling (SMM) allow researchers to determine whether or not a significant difference exists between groups' factor means. Strong invariance is typically recommended when interpreting latent mean differences. The extent of the impact of noninvariant…

Comment on 'Current Budget of the Atmospheric Electric Global Circuit'

NASA Technical Reports Server (NTRS)

Driscoll, Kevin T.; Blakeslee, Richard J.

1996-01-01

In this paper, three major issues relevant to Kasemir's new model will be addressed. The first concerns Kasemir's assertion that there are significant differences between the potentials associated with the new model and the conventional model. A recalculation of these potentials reveals that both models provide equivalent results for the potential difference between the Earth and ionosphere. The second issue to be addressed is Kasemir's assertion that discrepancies in the electric potentials associated with both models can be attributed to modeling the Earth as a sphere, instead of as a planar surface. A simple analytical comparison will demonstrate that differences in the equations for the potentials of the atmosphere derived with a spherical and a planar Earth are negligible for applications to global current flow. Finally, the third issue to be discussed is Kasemir's claim that numerous aspects of the conventional model are incorrect, including the role of the ionosphere in global current flow as well as the significance of cloud-to-ground lightning in supplying charge to the global circuit. In order to refute these misconceptions, it will be shown that these aspects related to the flow of charge in the atmosphere are accurately described by the conventional model of the global circuit.

Modelling individual difference in visual categorization.

PubMed

Shen, Jianhong; Palmeri, Thomas J

Recent years has seen growing interest in understanding, characterizing, and explaining individual differences in visual cognition. We focus here on individual differences in visual categorization. Categorization is the fundamental visual ability to group different objects together as the same kind of thing. Research on visual categorization and category learning has been significantly informed by computational modeling, so our review will focus both on how formal models of visual categorization have captured individual differences and how individual difference have informed the development of formal models. We first examine the potential sources of individual differences in leading models of visual categorization, providing a brief review of a range of different models. We then describe several examples of how computational models have captured individual differences in visual categorization. This review also provides a bit of an historical perspective, starting with models that predicted no individual differences, to those that captured group differences, to those that predict true individual differences, and to more recent hierarchical approaches that can simultaneously capture both group and individual differences in visual categorization. Via this selective review, we see how considerations of individual differences can lead to important theoretical insights into how people visually categorize objects in the world around them. We also consider new directions for work examining individual differences in visual categorization.

Modelling individual difference in visual categorization

PubMed Central

Shen, Jianhong; Palmeri, Thomas J.

2016-01-01

Recent years has seen growing interest in understanding, characterizing, and explaining individual differences in visual cognition. We focus here on individual differences in visual categorization. Categorization is the fundamental visual ability to group different objects together as the same kind of thing. Research on visual categorization and category learning has been significantly informed by computational modeling, so our review will focus both on how formal models of visual categorization have captured individual differences and how individual difference have informed the development of formal models. We first examine the potential sources of individual differences in leading models of visual categorization, providing a brief review of a range of different models. We then describe several examples of how computational models have captured individual differences in visual categorization. This review also provides a bit of an historical perspective, starting with models that predicted no individual differences, to those that captured group differences, to those that predict true individual differences, and to more recent hierarchical approaches that can simultaneously capture both group and individual differences in visual categorization. Via this selective review, we see how considerations of individual differences can lead to important theoretical insights into how people visually categorize objects in the world around them. We also consider new directions for work examining individual differences in visual categorization. PMID:28154496

Methods to Register Models and Input/Output Parameters for Integrated Modeling

EPA Science Inventory

Significant resources can be required when constructing integrated modeling systems. In a typical application, components (e.g., models and databases) created by different developers are assimilated, requiring the framework’s functionality to bridge the gap between the user’s kno...

High Stakes Tests with Self-Selected Essay Questions: Addressing Issues of Fairness

ERIC Educational Resources Information Center

Lamprianou, Iasonas

2008-01-01

This study investigates the effect of reporting the unadjusted raw scores in a high-stakes language exam when raters differ significantly in severity and self-selected questions differ significantly in difficulty. More sophisticated models, introducing meaningful facets and parameters, are successively used to investigate the characteristics of…

Sex differences in mechanical allodynia: how can it be preclinically quantified and analyzed?

PubMed Central

Nicotra, Lauren; Tuke, Jonathan; Grace, Peter M.; Rolan, Paul E.; Hutchinson, Mark R.

2014-01-01

Translating promising preclinical drug discoveries to successful clinical trials remains a significant hurdle in pain research. Although animal models have significantly contributed to understanding chronic pain pathophysiology, the majority of research has focused on male rodents using testing procedures that produce sex difference data that do not align well with comparable clinical experiences. Additionally, the use of animal pain models presents ongoing ethical challenges demanding continuing refinement of preclinical methods. To this end, this study sought to test a quantitative allodynia assessment technique and associated statistical analysis in a modified graded nerve injury pain model with the aim to further examine sex differences in allodynia. Graded allodynia was established in male and female Sprague Dawley rats by altering the number of sutures placed around the sciatic nerve and quantified by the von Frey test. Linear mixed effects modeling regressed response on each fixed effect (sex, oestrus cycle, pain treatment). On comparison with other common von Frey assessment techniques, utilizing lower threshold filaments than those ordinarily tested, at 1 s intervals, appropriately and successfully investigated female mechanical allodynia, revealing significant sex and oestrus cycle difference across the graded allodynia that other common behavioral methods were unable to detect. Utilizing this different von Frey approach and graded allodynia model, a single suture inflicting less allodynia was sufficient to demonstrate exaggerated female mechanical allodynia throughout the phases of dioestrus and pro-oestrus. Refining the von Frey testing method, statistical analysis technique and the use of a graded model of chronic pain, allowed for examination of the influences on female mechanical nociception that other von Frey methods cannot provide. PMID:24592221

Measurements using orthodontic analysis software on digital models obtained by 3D scans of plaster casts : Intrarater reliability and validity.

PubMed

Czarnota, Judith; Hey, Jeremias; Fuhrmann, Robert

2016-01-01

The purpose of this work was to determine the reliability and validity of measurements performed on digital models with a desktop scanner and analysis software in comparison with measurements performed manually on conventional plaster casts. A total of 20 pairs of plaster casts reflecting the intraoral conditions of 20 fully dentate individuals were digitized using a three-dimensional scanner (D700; 3Shape). A series of defined parameters were measured both on the resultant digital models with analysis software (Ortho Analyzer; 3Shape) and on the original plaster casts with a digital caliper (Digimatic CD-15DCX; Mitutoyo). Both measurement series were repeated twice and analyzed for intrarater reliability based on intraclass correlation coefficients (ICCs). The results from the digital models were evaluated for their validity against the casts by calculating mean-value differences and associated 95 % limits of agreement (Bland-Altman method). Statistically significant differences were identified via a paired t test. Significant differences were obtained for 16 of 24 tooth-width measurements, for 2 of 5 sites of contact-point displacement in the mandibular anterior segment, for overbite, for maxillary intermolar distance, for Little's irregularity index, and for the summation indices of maxillary and mandibular incisor width. Overall, however, both the mean differences between the results obtained on the digital models versus on the plaster casts and the dispersion ranges associated with these differences suggest that the deviations incurred by the digital measuring technique are not clinically significant. Digital models are adequately reproducible and valid to be employed for routine measurements in orthodontic practice.

Strategies for Testing Statistical and Practical Significance in Detecting DIF with Logistic Regression Models

ERIC Educational Resources Information Center

Fidalgo, Angel M.; Alavi, Seyed Mohammad; Amirian, Seyed Mohammad Reza

2014-01-01

This study examines three controversial aspects in differential item functioning (DIF) detection by logistic regression (LR) models: first, the relative effectiveness of different analytical strategies for detecting DIF; second, the suitability of the Wald statistic for determining the statistical significance of the parameters of interest; and…

Effective pollutant emission heights for atmospheric transport modelling based on real-world information.

PubMed

Pregger, Thomas; Friedrich, Rainer

2009-02-01

Emission data needed as input for the operation of atmospheric models should not only be spatially and temporally resolved. Another important feature is the effective emission height which significantly influences modelled concentration values. Unfortunately this information, which is especially relevant for large point sources, is usually not available and simple assumptions are often used in atmospheric models. As a contribution to improve knowledge on emission heights this paper provides typical default values for the driving parameters stack height and flue gas temperature, velocity and flow rate for different industrial sources. The results were derived from an analysis of the probably most comprehensive database of real-world stack information existing in Europe based on German industrial data. A bottom-up calculation of effective emission heights applying equations used for Gaussian dispersion models shows significant differences depending on source and air pollutant and compared to approaches currently used for atmospheric transport modelling.

Heart Performance Determination by Visualization in Larval Fishes: Influence of Alternative Models for Heart Shape and Volume

PubMed Central

Perrichon, Prescilla; Grosell, Martin; Burggren, Warren W.

2017-01-01

Understanding cardiac function in developing larval fishes is crucial for assessing their physiological condition and overall health. Cardiac output measurements in transparent fish larvae and other vertebrates have long been made by analyzing videos of the beating heart, and modeling this structure using a conventional simple prolate spheroid shape model. However, the larval fish heart changes shape during early development and subsequent maturation, but no consideration has been made of the effect of different heart geometries on cardiac output estimation. The present study assessed the validity of three different heart models (the “standard” prolate spheroid model as well as a cylinder and cone tip + cylinder model) applied to digital images of complete cardiac cycles in larval mahi-mahi and red drum. The inherent error of each model was determined to allow for more precise calculation of stroke volume and cardiac output. The conventional prolate spheroid and cone tip + cylinder models yielded significantly different stroke volume values at 56 hpf in red drum and from 56 to 104 hpf in mahi. End-diastolic and stroke volumes modeled by just a simple cylinder shape were 30–50% higher compared to the conventional prolate spheroid. However, when these values of stroke volume multiplied by heart rate to calculate cardiac output, no significant differences between models emerged because of considerable variability in heart rate. Essentially, the conventional prolate spheroid shape model provides the simplest measurement with lowest variability of stroke volume and cardiac output. However, assessment of heart function—especially if stroke volume is the focus of the study—should consider larval heart shape, with different models being applied on a species-by-species and developmental stage-by-stage basis for best estimation of cardiac output. PMID:28725199

Biomechanical analysis of asymmetric mesio-distal molar positions loaded by a symmetric cervical headgear.

PubMed

Kizilova, Natalya; Geramy, Allahyar; Romashov, Yurij

2016-01-01

The plane 2D model and 3d finite element model of the headgear attached to two molars with different mesio-distal location are studied to show the asymmetric mechanical effects produced by symmetrically loaded headgear. In daily dental practice the asymmetrical location of molars is usually ignored. Six 3D finite element models of a symmetric cervical headgear were designed in SolidWorks 2011. The models showed symmetric molar position (model 1), 0.5 to 2 mm of anterior-posterior molar difference (models 2-5) and a significant asymmetry with 10 mm of difference in the locations (model 6). The head gear was loaded with 3N of force applied at the cervical headgear. The forces and moments produced on terminal molars are assessed. It is shown the difference between the forces acting at the longer and shorter outer arms of the headgear increases with increase in the distance. The significant numeric difference in the forces has been found: from 0.0082 N (model 1) to 0.0324 N (model 5) and 0.146 N (model 6). These small forces may produce unplanned distal tipping and rotation of the molars around their vertical axes. The most important funding was found as a clockwise yaw moment in the system when is viewed superio-inferiorly. The yaw moment has been computed between -0.646 Nmm (model 1) and -1.945 N mm (model 5). Therefore even small asymmetry in location of molars loaded by a symmetric cervical headgear will produce undesirable movement and rotation of the teeth that must be taken into account before applying the treatment.

Comparing geological and statistical approaches for element selection in sediment tracing research

NASA Astrophysics Data System (ADS)

Laceby, J. Patrick; McMahon, Joe; Evrard, Olivier; Olley, Jon

2015-04-01

Elevated suspended sediment loads reduce reservoir capacity and significantly increase the cost of operating water treatment infrastructure, making the management of sediment supply to reservoirs of increasingly importance. Sediment fingerprinting techniques can be used to determine the relative contributions of different sources of sediment accumulating in reservoirs. The objective of this research is to compare geological and statistical approaches to element selection for sediment fingerprinting modelling. Time-integrated samplers (n=45) were used to obtain source samples from four major subcatchments flowing into the Baroon Pocket Dam in South East Queensland, Australia. The geochemistry of potential sources were compared to the geochemistry of sediment cores (n=12) sampled in the reservoir. The geochemical approach selected elements for modelling that provided expected, observed and statistical discrimination between sediment sources. Two statistical approaches selected elements for modelling with the Kruskal-Wallis H-test and Discriminatory Function Analysis (DFA). In particular, two different significance levels (0.05 & 0.35) for the DFA were included to investigate the importance of element selection on modelling results. A distribution model determined the relative contributions of different sources to sediment sampled in the Baroon Pocket Dam. Elemental discrimination was expected between one subcatchment (Obi Obi Creek) and the remaining subcatchments (Lexys, Falls and Bridge Creek). Six major elements were expected to provide discrimination. Of these six, only Fe2O3 and SiO2 provided expected, observed and statistical discrimination. Modelling results with this geological approach indicated 36% (+/- 9%) of sediment sampled in the reservoir cores were from mafic-derived sources and 64% (+/- 9%) were from felsic-derived sources. The geological and the first statistical approach (DFA0.05) differed by only 1% (σ 5%) for 5 out of 6 model groupings with only the Lexys Creek modelling results differing significantly (35%). The statistical model with expanded elemental selection (DFA0.35) differed from the geological model by an average of 30% for all 6 models. Elemental selection for sediment fingerprinting therefore has the potential to impact modeling results. Accordingly is important to incorporate both robust geological and statistical approaches when selecting elements for sediment fingerprinting. For the Baroon Pocket Dam, management should focus on reducing the supply of sediments derived from felsic sources in each of the subcatchments.

The phase model of burnout and employee turnover.

PubMed

Goodman, Eric A; Boss, R Wayne

2002-01-01

This study explores the phase model of burnout and investigates its relationship to actual turnover in a hospital. The results indicate that employees who turnover have significantly higher burnout phase scores that those who stay in the organization. A further comparison of voluntary and involuntary turnover demonstrates that there is no significant differences on burnout phase scores. The findings lend support to the usefulness of the phase model of burnout.

Correlation of FMISO simulations with pimonidazole-stained tumor xenografts: A question of O{sub 2} consumption?

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

Wack, L. J., E-mail: linda-jacqueline.wack@med.uni

Purpose: To compare a dedicated simulation model for hypoxia PET against tumor microsections stained for different parameters of the tumor microenvironment. The model can readily be adapted to a variety of conditions, such as different human head and neck squamous cell carcinoma (HNSCC) xenograft tumors. Methods: Nine different HNSCC tumor models were transplanted subcutaneously into nude mice. Tumors were excised and immunoflourescently labeled with pimonidazole, Hoechst 33342, and CD31, providing information on hypoxia, perfusion, and vessel distribution, respectively. Hoechst and CD31 images were used to generate maps of perfused blood vessels on which tissue oxygenation and the accumulation of themore » hypoxia tracer FMISO were mathematically simulated. The model includes a Michaelis–Menten relation to describe the oxygen consumption inside tissue. The maximum oxygen consumption rate M{sub 0} was chosen as the parameter for a tumor-specific optimization as it strongly influences tracer distribution. M{sub 0} was optimized on each tumor slice to reach optimum correlations between FMISO concentration 4 h postinjection and pimonidazole staining intensity. Results: After optimization, high pixel-based correlations up to R{sup 2} = 0.85 were found for individual tissue sections. Experimental pimonidazole images and FMISO simulations showed good visual agreement, confirming the validity of the approach. Median correlations per tumor model varied significantly (p < 0.05), with R{sup 2} ranging from 0.20 to 0.54. The optimum maximum oxygen consumption rate M{sub 0} differed significantly (p < 0.05) between tumor models, ranging from 2.4 to 5.2 mm Hg/s. Conclusions: It is feasible to simulate FMISO distributions that match the pimonidazole retention patterns observed in vivo. Good agreement was obtained for multiple tumor models by optimizing the oxygen consumption rate, M{sub 0}, whose optimum value differed significantly between tumor models.« less

Multi-scale quantum point contact model for filamentary conduction in resistive random access memories devices

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

Lian, Xiaojuan, E-mail: xjlian2005@gmail.com; Cartoixà, Xavier; Miranda, Enrique

2014-06-28

We depart from first-principle simulations of electron transport along paths of oxygen vacancies in HfO{sub 2} to reformulate the Quantum Point Contact (QPC) model in terms of a bundle of such vacancy paths. By doing this, the number of model parameters is reduced and a much clearer link between the microscopic structure of the conductive filament (CF) and its electrical properties can be provided. The new multi-scale QPC model is applied to two different HfO{sub 2}-based devices operated in the unipolar and bipolar resistive switching (RS) modes. Extraction of the QPC model parameters from a statistically significant number of CFsmore » allows revealing significant structural differences in the CF of these two types of devices and RS modes.« less

Establishment of a mathematic model for predicting malignancy in solitary pulmonary nodules.

PubMed

Zhang, Man; Zhuo, Na; Guo, Zhanlin; Zhang, Xingguang; Liang, Wenhua; Zhao, Sheng; He, Jianxing

2015-10-01

The aim of this study was to establish a model for predicting the probability of malignancy in solitary pulmonary nodules (SPNs) and provide guidance for the diagnosis and follow-up intervention of SPNs. We retrospectively analyzed the clinical data and computed tomography (CT) images of 294 patients with a clear pathological diagnosis of SPN. Multivariate logistic regression analysis was used to screen independent predictors of the probability of malignancy in the SPN and to establish a model for predicting malignancy in SPNs. Then, another 120 SPN patients who did not participate in the model establishment were chosen as group B and used to verify the accuracy of the prediction model. Multivariate logistic regression analysis showed that there were significant differences in age, smoking history, maximum diameter of nodules, spiculation, clear borders, and Cyfra21-1 levels between subgroups with benign and malignant SPNs (P<0.05). These factors were identified as independent predictors of malignancy in SPNs. The area under the curve (AUC) was 0.910 [95% confidence interval (CI), 0.857-0.963] in model with Cyfra21-1 significantly better than 0.812 (95% CI, 0.763-0.861) in model without Cyfra21-1 (P=0.008). The area under receiver operating characteristic (ROC) curve of our model is significantly higher than the Mayo model, VA model and Peking University People's (PKUPH) model. Our model (AUC =0.910) compared with Brock model (AUC =0.878, P=0.350), the difference was not statistically significant. The model added Cyfra21-1 could improve prediction. The prediction model established in this study can be used to assess the probability of malignancy in SPNs, thereby providing help for the diagnosis of SPNs and the selection of follow-up interventions.

A model-based 'varimax' sampling strategy for a heterogeneous population.

PubMed

Akram, Nuzhat A; Farooqi, Shakeel R

2014-01-01

Sampling strategies are planned to enhance the homogeneity of a sample, hence to minimize confounding errors. A sampling strategy was developed to minimize the variation within population groups. Karachi, the largest urban agglomeration in Pakistan, was used as a model population. Blood groups ABO and Rh factor were determined for 3000 unrelated individuals selected through simple random sampling. Among them five population groups, namely Balochi, Muhajir, Pathan, Punjabi and Sindhi, based on paternal ethnicity were identified. An index was designed to measure the proportion of admixture at parental and grandparental levels. Population models based on index score were proposed. For validation, 175 individuals selected through stratified random sampling were genotyped for the three STR loci CSF1PO, TPOX and TH01. ANOVA showed significant differences across the population groups for blood groups and STR loci distribution. Gene diversity was higher across the sub-population model than in the agglomerated population. At parental level gene diversities are significantly higher across No admixture models than Admixture models. At grandparental level the difference was not significant. A sub-population model with no admixture at parental level was justified for sampling the heterogeneous population of Karachi.

A Dynamic Spatio-Temporal Model to Investigate the Effect of Cattle Movements on the Spread of Bluetongue BTV-8 in Belgium

PubMed Central

Ensoy, Chellafe; Aerts, Marc; Welby, Sarah; Van der Stede, Yves; Faes, Christel

2013-01-01

When Bluetongue Virus Serotype 8 (BTV-8) was first detected in Northern Europe in 2006, several guidelines were immediately put into place with the goal to protect farms and stop the spreading of the disease. This however did not prevent further rapid spread of BTV-8 across Northern Europe. Using information on the 2006 Bluetongue outbreak in cattle farms in Belgium, a spatio-temporal transmission model was formulated. The model quantifies the local transmission of the disease between farms within a municipality, the short-distance transmission between farms across neighbouring municipalities and the transmission as a result of cattle movement. Different municipality-level covariates such as farm density, land composition variables, temperature and precipitation, were assessed as possibly influencing each component of the transmission process. Results showed a significant influence of the different covariates in each model component, particularly the significant effect of temperature and precipitation values in the number of infected farms. The model which allowed us to predict the dynamic spreading of BTV for different movement restriction scenarios, also affirmed the significant impact of cattle movement in the 2006 BTV outbreak pattern. Simulation results further showed the importance of considering the size of restriction zones in the formulation of guidelines for animal infectious diseases. PMID:24244324

A dynamic spatio-temporal model to investigate the effect of cattle movements on the spread of bluetongue BTV-8 in Belgium.

PubMed

Ensoy, Chellafe; Aerts, Marc; Welby, Sarah; Van der Stede, Yves; Faes, Christel

2013-01-01

When Bluetongue Virus Serotype 8 (BTV-8) was first detected in Northern Europe in 2006, several guidelines were immediately put into place with the goal to protect farms and stop the spreading of the disease. This however did not prevent further rapid spread of BTV-8 across Northern Europe. Using information on the 2006 Bluetongue outbreak in cattle farms in Belgium, a spatio-temporal transmission model was formulated. The model quantifies the local transmission of the disease between farms within a municipality, the short-distance transmission between farms across neighbouring municipalities and the transmission as a result of cattle movement. Different municipality-level covariates such as farm density, land composition variables, temperature and precipitation, were assessed as possibly influencing each component of the transmission process. Results showed a significant influence of the different covariates in each model component, particularly the significant effect of temperature and precipitation values in the number of infected farms. The model which allowed us to predict the dynamic spreading of BTV for different movement restriction scenarios, also affirmed the significant impact of cattle movement in the 2006 BTV outbreak pattern. Simulation results further showed the importance of considering the size of restriction zones in the formulation of guidelines for animal infectious diseases.

Bioenergetic model estimates of interannual and spatial patterns in consumption demand and growth potential of juvenile pink salmon ( Oncorhynchus gorbuscha) in the Gulf of Alaska

NASA Astrophysics Data System (ADS)

Moss, Jamal H.; Beauchamp, David A.; Cross, Alison D.; Farley, Edward V.; Murphy, James M.; Helle, John H.; Walker, Robert V.; Myers, Katherine W.

2009-12-01

A bioenergetic model of juvenile pink salmon ( Oncorhynchus gorbuscha) was used to estimate daily prey consumption and growth potential of four ocean habitats in the Gulf of Alaska during 2001 and 2002. Growth potential was not significantly higher in 2002 than in 2001 at an alpha level of 0.05 ( P=0.073). Average differences in growth potential across habitats were minimal (slope habitat=0.844 g d -1, shelf habitat=0.806 g d -1, offshore habitat=0.820 g d -1, and nearshore habitat=0.703 g d -1) and not significantly different ( P=0.630). Consumption demand differed significantly between hatchery and wild stocks ( P=0.035) when examined within year due to the interaction between hatchery verses wild origin and year. However, the overall effect of origin across years was not significant ( P=0.705) due to similar total amounts of prey consumed by all juvenile pink salmon in both study years. We anticipated that years in which ocean survival was high would have had high growth potential, but this relationship did not prove to be true. Therefore, modeled growth potential may not be useful as a tool for forecasting survival of Prince William Sound hatchery pink salmon stocks. Significant differences in consumption demand and a two-fold difference in nearshore abundance during 2001 of hatchery and wild pink salmon confirmed the existence of strong and variable interannual competition and the importance of the nearshore region as being a potential competitive bottleneck.

Bioenergetic model estimates of interannual and spatial patterns in consumption demand and growth potential of juvenile pink salmon (Oncorhynchus gorbuscha) in the Gulf of Alaska

USGS Publications Warehouse

Moss, J.H.; Beauchamp, D.A.; Cross, A.D.; Farley, E.V.; Murphy, J.M.; Helle, J.H.; Walker, R.V.; Myers, K.W.

2009-01-01

A bioenergetic model of juvenile pink salmon (Oncorhynchus gorbuscha) was used to estimate daily prey consumption and growth potential of four ocean habitats in the Gulf of Alaska during 2001 and 2002. Growth potential was not significantly higher in 2002 than in 2001 at an alpha level of 0.05 (P=0.073). Average differences in growth potential across habitats were minimal (slope habitat=0.844 g d-1, shelf habitat=0.806 g d-1, offshore habitat=0.820 g d-1, and nearshore habitat=0.703 g d-1) and not significantly different (P=0.630). Consumption demand differed significantly between hatchery and wild stocks (P=0.035) when examined within year due to the interaction between hatchery verses wild origin and year. However, the overall effect of origin across years was not significant (P=0.705) due to similar total amounts of prey consumed by all juvenile pink salmon in both study years. We anticipated that years in which ocean survival was high would have had high growth potential, but this relationship did not prove to be true. Therefore, modeled growth potential may not be useful as a tool for forecasting survival of Prince William Sound hatchery pink salmon stocks. Significant differences in consumption demand and a two-fold difference in nearshore abundance during 2001 of hatchery and wild pink salmon confirmed the existence of strong and variable interannual competition and the importance of the nearshore region as being a potential competitive bottleneck.

Development of Operational Wave-Tide-Storm surges Coupling Prediction System

NASA Astrophysics Data System (ADS)

You, S. H.; Park, S. W.; Kim, J. S.; Kim, K. L.

2009-04-01

The Korean Peninsula is surrounded by the Yellow Sea, East China Sea, and East Sea. This complex oceanographic system includes large tides in the Yellow Sea and seasonally varying monsoon and typhoon events. For Korea's coastal regions, floods caused by wave and storm surges are among the most serious threats. To predict more accurate wave and storm surges, the development of coupling wave-tide-storm surges prediction system is essential. For the time being, wave and storm surges predictions are still made separately in KMA (Korea Meteorological Administration) and most operational institute. However, many researchers have emphasized the effects of tides and storm surges on wind waves and recommended further investigations into the effects of wave-tide-storm surges interactions and coupling module. In Korea, especially, tidal height and current give a great effect on the wave prediction in the Yellow sea where is very high tide and related research is not enough. At present, KMA has operated the wave (RWAM : Regional Wave Model) and storm surges/tide prediction system (STORM : Storm Surges/Tide Operational Model) for ocean forecasting. The RWAM is WAVEWATCH III which is a third generation wave model developed by Tolman (1989). The STORM is based on POM (Princeton Ocean Model, Blumberg and Mellor, 1987). The RWAM and STORM cover the northwestern Pacific Ocean from 115°E to 150°E and from 20°N to 52°N. The horizontal grid intervals are 1/12° in both latitudinal and longitudinal directions. These two operational models are coupled to simulate wave heights for typhoon case. The sea level and current simulated by storm surge model are used for the input of wave model with 3 hour interval. The coupling simulation between wave and storm surge model carried out for Typhoon Nabi (0514), Shanshan(0613) and Nari (0711) which were effected on Korea directly. We simulated significant wave height simulated by wave model and coupling model and compared difference between uncoupling and coupling cases for each typhoon. When the typhoon Nabi hit at southern coast of Kyushu, predicted significant wave height reached over 10 m. The difference of significant wave height between wave and wave-tide-storm surges model represents large variation at the southwestern coast of Korea with about 0.5 m. Other typhoon cases also show similar results with typhoon Nabi case. For typhoon Shanshan case the difference of significant wave height reached up to 0.3 m. When the typhoon Nari was affected in the southern coast of Korea, predicted significant wave height was about 5m. The typhoon Nari case also shows the difference of significant wave height similar with other typhoon cases. Using the observation from ocean buoy operated by KMA, we compared wave information simulated by wave and wave-storm surges coupling model. The significant wave height simulated by wave-tide-storm surges model shows the tidal modulation features in the western and southern coast of Korea. And the difference of significant wave height between two models reached up to 0.5 m. The coupling effect also can be identified in the wave direction, wave period and wave length. In addition, wave spectrum is also changeable due to coupling effect of wave-tide-storm surges model. The development, testing and application of a coupling module in which wave-tide-storm surges are incorporated within the frame of KMA Ocean prediction system, has been considered as a step forward in respect of ocean forecasting. In addition, advanced wave prediction model will be applicable to the effect of ocean in the weather forecasting system. The main purpose of this study is to show how the coupling module developed and to report on a series of experiments dealing with the sensitivities and real case prediction of coupling wave-tide-storm surges prediction system.

Analysis of the Sheltered Instruction Observation Protocol Model on Academic Performance of English Language Learners

NASA Astrophysics Data System (ADS)

Ingram, Sandra W.

This quantitative comparative descriptive study involved analyzing archival data from end-of-course (EOC) test scores in biology of English language learners (ELLs) taught or not taught using the sheltered instruction observation protocol (SIOP) model. The study includes descriptions and explanations of the benefits of the SIOP model to ELLs, especially in content area subjects such as biology. Researchers have shown that ELLs in high school lag behind their peers in academic achievement in content area subjects. Much of the research on the SIOP model took place in elementary and middle school, and more research was necessary at the high school level. This study involved analyzing student records from archival data to describe and explain if the SIOP model had an effect on the EOC test scores of ELLs taught or not taught using it. The sample consisted of 527 Hispanic students (283 females and 244 males) from Grades 9-12. An independent sample t-test determined if a significant difference existed in the mean EOC test scores of ELLs taught using the SIOP model as opposed to ELLs not taught using the SIOP model. The results indicated that a significant difference existed between EOC test scores of ELLs taught using the SIOP model and ELLs not taught using the SIOP model (p = .02). A regression analysis indicated a significant difference existed in the academic performance of ELLs taught using the SIOP model in high school science, controlling for free and reduced-price lunch (p = .001) in predicting passing scores on the EOC test in biology at the school level. The data analyzed for free and reduced-price lunch together with SIOP data indicated that both together were not significant (p = .175) for predicting passing scores on the EOC test in high school biology. Future researchers should repeat the study with student-level data as opposed to school-level data, and data should span at least three years.

Modifications to the Water Vapor Continuum in the Microwave Suggested by Ground-Based 150-GHz Observations

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

Turner, D. D.; Cadeddu, M. P.; Lohnert, U.

2009-10-01

Abstract—Ground-based observations from two different radiometers are used to evaluate commonly used microwave/ millimeter-wave propagation models at 150 GHz. This frequency has strong sensitivity to changes in precipitable water vapor (PWV) and cloud liquid water. The observations were collected near Hesselbach, Germany, as part of the Atmospheric Radiation Measurement program’s support of the General Observing Period and the Convective and Orographic Precipitation Study. The observations from the two radiometers agree well with each other, with a slope of 0.993 and a mean bias of 0.12 K. The observations demonstrate that the relative sensitivity of the different absorption models to PWVmore » in clear-sky conditions at 150 GHz is significant and that four models differ significantly from the observed brightness temperature. These models were modified to get agreement with the 150-GHz observations, where the PWV ranged from 0.35 to 2.88 cm. The models were modified by adjusting the strength of the foreign- and self-broadened water vapor continuum coefficients, where the magnitude was model dependent. In all cases, the adjustment to the two components of the water vapor continuum was in opposite directions (i.e., increasing the contribution from the foreign-broadened component while decreasing contribution from the self-broadened component or vice versa). While the original models had significant disagreements relative to each other, the resulting modified models show much better agreement relative to each other throughout the microwave spectrum. The modified models were evaluated using independent observations at 31.4 GHz.« less

Meeting the Needs of Children with Medical Complexity Using a Telehealth Advanced Practice Registered Nurse Care Coordination Model

PubMed Central

Erickson, Mary; Lunos, Scott; Finkelstein, Stanley M.; Looman, Wendy; Celebreeze, Margaret; Garwick, Ann

2015-01-01

Effective care coordination is a key quality and safety strategy for populations with chronic conditions, including children with medical complexity (CMC). However, gaps remain in parent report of the need for care coordination help and receipt of care coordination help. New models must close this gap while maintaining family-centered focus. A three-armed randomized controlled trial conducted in an established medical home utilized an advanced practice registered nurse intervention based on Presler’s model of clinic-based care coordination. The model supported families of CMC across settings using telephone only or telephone and video telehealth care coordination. Effectiveness was evaluated from many perspectives and this paper reports on a subset of outcomes that includes family-centered care (FCC), need for care coordination help and adequacy of care coordination help received. FCC at baseline and end of study showed no significant difference between groups. Median FCC scores of 18.0–20.0 across all groups indicated high FCC within the medical home. No significant differences were found in the need for care coordination help within or between groups and over time. No significant difference was found in the adequacy of help received between groups at baseline. However, this indicator increased significantly over time for both intervention groups. These findings suggest that in an established medical home with high levels of FCC, families of CMC have unmet needs for care coordination help that are addressed by the APRN telehealth care coordination model. PMID:25424455

Meeting the needs of children with medical complexity using a telehealth advanced practice registered nurse care coordination model.

PubMed

Cady, Rhonda G; Erickson, Mary; Lunos, Scott; Finkelstein, Stanley M; Looman, Wendy; Celebreeze, Margaret; Garwick, Ann

2015-07-01

Effective care coordination is a key quality and safety strategy for populations with chronic conditions, including children with medical complexity (CMC). However, gaps remain in parent report of the need for care coordination help and receipt of care coordination help. New models must close this gap while maintaining family-centered focus. A three-armed randomized controlled trial conducted in an established medical home utilized an advanced practice registered nurse intervention based on Presler's model of clinic-based care coordination. The model supported families of CMC across settings using telephone only or telephone and video telehealth care coordination. Effectiveness was evaluated from many perspectives and this paper reports on a subset of outcomes that includes family-centered care (FCC), need for care coordination help and adequacy of care coordination help received. FCC at baseline and end of study showed no significant difference between groups. Median FCC scores of 18.0-20.0 across all groups indicated high FCC within the medical home. No significant differences were found in the need for care coordination help within or between groups and over time. No significant difference was found in the adequacy of help received between groups at baseline. However, this indicator increased significantly over time for both intervention groups. These findings suggest that in an established medical home with high levels of FCC, families of CMC have unmet needs for care coordination help that are addressed by the APRN telehealth care coordination model.

The effect of age and speed on foot and ankle kinematics assessed using a 4-segment foot model

PubMed Central

van Hoeve, Sander; Leenstra, Bernard; Willems, Paul; Poeze, Martijn; Meijer, Kenneth

2017-01-01

Abstract Background: The effects of age and speed on foot and ankle kinematics in gait studies using foot models are not fully understood, whereas this can have significant influence. We analyzed these variables with the 4-segment Oxford foot model. Methods: Twenty-one healthy subjects (aged 20–65 years) were recruited for gait analysis. The effect of speed on foot and ankle kinematics was assessed by comparing results during slow walking and fast walking. To assess the effect of age, a group of 13 healthy young adults (aged 20–24 years) were compared with a group of 8 older adults (aged 53–65 years). Also, the interaction between age and speed was analyzed. Results: Regarding speed, there was a significant difference between forefoot/hindfoot motion in the sagittal plane (flexion/extension) during both loading- and push-off phase (P = .004, P < .001). Between hindfoot/tibia, there was a significant difference for all parameters except for motion in the sagittal plane (flexion/extension) during push-off phase (P = .5). Age did not significantly influence kinematics. There was no interaction between age and speed. Conclusion: Our analysis found that speed significantly influenced the kinematic outcome parameters. This was more pronounced in the ankle joint. In contrast, no significant differences were found between younger and older healthy subjects. PMID:28858109

Effects of sample survey design on the accuracy of classification tree models in species distribution models

USGS Publications Warehouse

Edwards, T.C.; Cutler, D.R.; Zimmermann, N.E.; Geiser, L.; Moisen, Gretchen G.

2006-01-01

We evaluated the effects of probabilistic (hereafter DESIGN) and non-probabilistic (PURPOSIVE) sample surveys on resultant classification tree models for predicting the presence of four lichen species in the Pacific Northwest, USA. Models derived from both survey forms were assessed using an independent data set (EVALUATION). Measures of accuracy as gauged by resubstitution rates were similar for each lichen species irrespective of the underlying sample survey form. Cross-validation estimates of prediction accuracies were lower than resubstitution accuracies for all species and both design types, and in all cases were closer to the true prediction accuracies based on the EVALUATION data set. We argue that greater emphasis should be placed on calculating and reporting cross-validation accuracy rates rather than simple resubstitution accuracy rates. Evaluation of the DESIGN and PURPOSIVE tree models on the EVALUATION data set shows significantly lower prediction accuracy for the PURPOSIVE tree models relative to the DESIGN models, indicating that non-probabilistic sample surveys may generate models with limited predictive capability. These differences were consistent across all four lichen species, with 11 of the 12 possible species and sample survey type comparisons having significantly lower accuracy rates. Some differences in accuracy were as large as 50%. The classification tree structures also differed considerably both among and within the modelled species, depending on the sample survey form. Overlap in the predictor variables selected by the DESIGN and PURPOSIVE tree models ranged from only 20% to 38%, indicating the classification trees fit the two evaluated survey forms on different sets of predictor variables. The magnitude of these differences in predictor variables throws doubt on ecological interpretation derived from prediction models based on non-probabilistic sample surveys. ?? 2006 Elsevier B.V. All rights reserved.

On Fitting Generalized Linear Mixed-effects Models for Binary Responses using Different Statistical Packages

PubMed Central

Zhang, Hui; Lu, Naiji; Feng, Changyong; Thurston, Sally W.; Xia, Yinglin; Tu, Xin M.

2011-01-01

Summary The generalized linear mixed-effects model (GLMM) is a popular paradigm to extend models for cross-sectional data to a longitudinal setting. When applied to modeling binary responses, different software packages and even different procedures within a package may give quite different results. In this report, we describe the statistical approaches that underlie these different procedures and discuss their strengths and weaknesses when applied to fit correlated binary responses. We then illustrate these considerations by applying these procedures implemented in some popular software packages to simulated and real study data. Our simulation results indicate a lack of reliability for most of the procedures considered, which carries significant implications for applying such popular software packages in practice. PMID:21671252

Analysis of the Casson and Carreau-Yasuda non-Newtonian blood models in steady and oscillatory flows using the lattice Boltzmann method

NASA Astrophysics Data System (ADS)

Boyd, Joshua; Buick, James M.; Green, Simon

2007-09-01

The lattice Boltzmann method is modified to allow the simulation of non-Newtonian shear-dependent viscosity models. Casson and Carreau-Yasuda non-Newtonian blood viscosity models are implemented and are used to compare two-dimensional Newtonian and non-Newtonian flows in the context of simple steady flow and oscillatory flow in straight and curved pipe geometries. It is found that compared to analogous Newtonian flows, both the Casson and Carreau-Yasuda flows exhibit significant differences in the steady flow situation. In the straight pipe oscillatory flows, both models exhibit differences in velocity and shear, with the largest differences occurring at low Reynolds and Womersley numbers. Larger differences occur for the Casson model. In the curved pipe Carreau-Yasuda model, moderate differences are observed in the velocities in the central regions of the geometries, and the largest shear rate differences are observed near the geometry walls. These differences may be important for the study of atherosclerotic progression.

The difference of detecting water mist and smoke by electromagnetic wave in simulation experiments

NASA Astrophysics Data System (ADS)

Zhang, Jingdi; Cui, Bing; Xiao, Si

2015-10-01

Although mist is similar to smoke in morphology, their compositions are very different. Therefore there is a significant difference between mist and smoke when detected by electromagnetic wave. This paper puts forward a kind of feasible solution based on Ansoft HFSS software about how to determine the forest fire by distinguishing mist and smoke above the forest. The experiments simulate the difference between mist and smoke model when detected by electromagnetic wave in different wavelengths. We find the mist and smoke model cannot absorb or reflect electromagnetic wave efficiently in Megahertz band. While in Gigahertz band mist model began to absorb and reflect electromagnetic wave above 650 Gigahertz band, but no change in smoke model. And the biggest difference appears in Terahertz band.

The Impact of National Cultural Differences on Nurses' Acceptance of Hospital Information Systems.

PubMed

Lin, Hsien-Cheng

2015-06-01

This study aims to explore the influence of national cultural differences on nurses' perceptions of their acceptance of hospital information systems. This study uses the perspective of Technology Acceptance Model; national cultural differences in terms of masculinity/femininity, individualism/collectivism, power distance, and uncertainty avoidance are incorporated into the Technology Acceptance Model as moderators, whereas time orientation is a control variable on hospital information system acceptance. A quantitative research design was used in this study; 261 participants, US and Taiwan RNs, all had hospital information system experience. Data were collected from November 2013 to February 2014 and analyzed using a t test to compare the coefficients for each moderator. The results show that individualism/collectivism, power distance, and uncertainty avoidance all exhibit significant difference on hospital information system acceptance; however, both masculinity/femininity and time orientation factors did not show significance. This study verifies that national cultural differences have significant influence on nurses' behavioral intention to use hospital information systems. Therefore, hospital information system providers should emphasize the way in which to integrate different technological functions to meet the needs of nurses from various cultural backgrounds.

Tooth-size discrepancy: A comparison between manual and digital methods

PubMed Central

Correia, Gabriele Dória Cabral; Habib, Fernando Antonio Lima; Vogel, Carlos Jorge

2014-01-01

Introduction Technological advances in Dentistry have emerged primarily in the area of diagnostic tools. One example is the 3D scanner, which can transform plaster models into three-dimensional digital models. Objective This study aimed to assess the reliability of tooth size-arch length discrepancy analysis measurements performed on three-dimensional digital models, and compare these measurements with those obtained from plaster models. Material and Methods To this end, plaster models of lower dental arches and their corresponding three-dimensional digital models acquired with a 3Shape R700T scanner were used. All of them had lower permanent dentition. Four different tooth size-arch length discrepancy calculations were performed on each model, two of which by manual methods using calipers and brass wire, and two by digital methods using linear measurements and parabolas. Results Data were statistically assessed using Friedman test and no statistically significant differences were found between the two methods (P > 0.05), except for values found by the linear digital method which revealed a slight, non-significant statistical difference. Conclusions Based on the results, it is reasonable to assert that any of these resources used by orthodontists to clinically assess tooth size-arch length discrepancy can be considered reliable. PMID:25279529

The relationship between race, cigarette smoking and carotid intimal medial thickness in systemic lupus erythematosus.

PubMed

Scalzi, L V; Bhatt, S; Gilkeson, R C; Shaffer, M L

2009-12-01

Racial differences are known to account for a higher incidence of systemic lupus erythematosus (SLE), as well as increased disease severity and mortality. The purpose of this study was to determine whether there are any race-specific risk factors that affect measures of subclinical atherosclerosis in SLE patients. Traditional and SLE-related cardiovascular disease (CVD) risk factors were assessed in 106 female SLE patients. Carotid medial intimal medial thickness (mIMT) and coronary artery calcification (CAC) were measured on all subjects. Differences were evaluated between races for all clinical, serologic, and CVD risk factors and the racial interactions with all covariables. Outcomes included mIMT and CAC. There were no significant differences between races with regard to mIMT or CAC. Significant covariables in the final model for mIMT included age, triglycerides, glucose, and race-age and race-smoking interactions. A prediction model with fixed significant covariables demonstrated that Black subjects with a smoking history had a significantly higher mIMT than Blacks who had never smoked, an effect not seen in Whites. There were no differences between having CAC or with the CAC scores between the races. In the final model for CAC, age and SLE disease duration were significant covariables impacting CAC. When controlling for other significant CVD covariables and interactions, Black women, but not White, with SLE with a history of smoking have higher mIMT measurements than those who have never smoked. This is the first report documenting the race-specific effect of smoking on subclinical measures of CVD in SLE.

Determining if Instructional Delivery Model Differences Exist in Remedial English

ERIC Educational Resources Information Center

Carter, LaTanya Woods

2012-01-01

The purpose of this causal comparative study is to test the theory of no significant difference that compares pre- and post-test assessment scores, controlling for the instructional delivery model of online and face-to-face students at a Mid-Atlantic university. Online education and virtual distance learning programs have increased in popularity…

Early Exposure to Direct Instruction and Subsequent Juvenile Delinquency: A Prospective Examination.

ERIC Educational Resources Information Center

Mills, Paulette E.; Cole, Kevin N.; Jenkins, Joseph R.; Dale, Philip S.

2002-01-01

A study examined juvenile delinquency outcomes for 171 children with disabilities participating in two different preschool models, one using direct instruction, the other using a cognitively oriented, child-directed model. At age 15, the groups did not differ significantly in their level of reported delinquency. (Contains references.) (Author/CR)

Using the Madeline Hunter Direct Instruction Model to Improve Outcomes Assessments in Marketing Programs

ERIC Educational Resources Information Center

Steward, Michelle D.; Martin, Gregory S.; Burns, Alvin C.; Bush, Ronald F.

2010-01-01

This study introduces marketing educators to the Madeline Hunter Direct Instruction Model (HDIM) as an approach to significantly and substantially improve student learning through course-embedded assessment. The effectiveness of the method is illustrated in three different marketing courses taught by three different marketing professors. The…

Evapotranspiration from drained wetlands: drivers, modeling, storage functions, and restoration implications

NASA Astrophysics Data System (ADS)

Shukla, S.; Wu, C. L.; Shrestha, N.

2017-12-01

Abstract Evapotranspiration (ET) is a major component of wetland and watershed water budgets. The effect of wetland drainage on ET is not well understood. We tested whether the current understanding of insignificant effect of drainage on ET in the temperate region wetlands applies to those in the sub-tropics. Eddy covariance (EC) based ET measurements were made for two years at two previously drained and geographically close wetlands in the Everglades region of Florida. One wetland was significantly drained with 97% of its storage capacity lost. The other was a more functional wetland with 42% of storage capacity lost. Annual average ET at the significantly drained wetland was 836 mm, 34% less than the function wetland (1271 mm) and the difference was statistically significant (p = 0.001). Such differences in wetland ET in the same climatic region have not been observed. The difference in ET was mainly due to drainage driven differences in inundation and associated effects on net radiation (Rn) and local relative humidity. Two daily ET models, a regression (r2 = 0.80) and a Relevance Vector Machine (RVM) model (r2 = 0.84), were developed with the latter being more robust. These models, when used in conjunction with hydrologic models, improved ET predictions for drained wetlands. Predictions from an integrated model showed that more intensely drained wetlands at higher elevation should be targeted for restoration of downstream flows (flooding) because they have the ability to loose higher water volume through ET which increases available water storage capacity of wetlands. Daily ET models can predict changes in ET for improved evaluation of basin-scale effects of restoration programs and climate change scenarios.

Comparing visual representations across human fMRI and computational vision

PubMed Central

Leeds, Daniel D.; Seibert, Darren A.; Pyles, John A.; Tarr, Michael J.

2013-01-01

Feedforward visual object perception recruits a cortical network that is assumed to be hierarchical, progressing from basic visual features to complete object representations. However, the nature of the intermediate features related to this transformation remains poorly understood. Here, we explore how well different computer vision recognition models account for neural object encoding across the human cortical visual pathway as measured using fMRI. These neural data, collected during the viewing of 60 images of real-world objects, were analyzed with a searchlight procedure as in Kriegeskorte, Goebel, and Bandettini (2006): Within each searchlight sphere, the obtained patterns of neural activity for all 60 objects were compared to model responses for each computer recognition algorithm using representational dissimilarity analysis (Kriegeskorte et al., 2008). Although each of the computer vision methods significantly accounted for some of the neural data, among the different models, the scale invariant feature transform (Lowe, 2004), encoding local visual properties gathered from “interest points,” was best able to accurately and consistently account for stimulus representations within the ventral pathway. More generally, when present, significance was observed in regions of the ventral-temporal cortex associated with intermediate-level object perception. Differences in model effectiveness and the neural location of significant matches may be attributable to the fact that each model implements a different featural basis for representing objects (e.g., more holistic or more parts-based). Overall, we conclude that well-known computer vision recognition systems may serve as viable proxies for theories of intermediate visual object representation. PMID:24273227

Finite-difference time-domain modeling of transient infrasonic wavefields excited by volcanic explosions

NASA Astrophysics Data System (ADS)

Kim, K.; Lees, J. M.

2011-03-01

Numerical modeling of waveform diffractions along the rim of a volcano vent shows high correlation to observed explosion signals at Karymsky Volcano, Kamchatka, Russia. The finite difference modeling assumed a gaussian source time function and an axisymmetric geometry. A clear demonstration of the significant distortion of infrasonic wavefronts was caused by diffraction at the vent rim edge. Data collected at Karymsky in 1997 and 1998 were compared to synthetic waveforms and variations of vent geometry were determined via grid search. Karymsky exhibited a wide range of variation in infrasonic waveforms, well explained by the diffraction, and modeled as changing vent geometry. Rim diffraction of volcanic infrasound is shown to be significant and must be accounted for when interpreting source physics from acoustic observations.

An investigation of meaningful understanding and effectiveness of the implementation of Piagetian and Ausubelian theories in physics instruction

NASA Astrophysics Data System (ADS)

Williams, Karen Ann

One section of college students (N = 25) enrolled in an algebra-based physics course was selected for a Piagetian-based learning cycle (LC) treatment while a second section (N = 25) studied in an Ausubelian-based meaningful verbal reception learning treatment (MVRL). This study examined the students' overall (concept + problem solving + mental model) meaningful understanding of force, density/Archimedes Principle, and heat. Also examined were students' meaningful understanding as measured by conceptual questions, problems, and mental models. In addition, students' learning orientations were examined. There were no significant posttest differences between the LC and MVRL groups for students' meaningful understanding or learning orientation. Piagetian and Ausubelian theories explain meaningful understanding for each treatment. Students from each treatment increased their meaningful understanding. However, neither group altered their learning orientation. The results of meaningful understanding as measured by conceptual questions, problem solving, and mental models were mixed. Differences were attributed to the weaknesses and strengths of each treatment. This research also examined four variables (treatment, reasoning ability, learning orientation, and prior knowledge) to find which best predicted students' overall meaningful understanding of physics concepts. None of these variables were significant predictors at the.05 level. However, when the same variables were used to predict students' specific understanding (i.e. concept, problem solving, or mental model understanding), the results were mixed. For forces and density/Archimedes Principle, prior knowledge and reasoning ability significantly predicted students' conceptual understanding. For heat, however, reasoning ability was the only significant predictor of concept understanding. Reasoning ability and treatment were significant predictors of students' problem solving for heat and forces. For density/Archimedes Principle, treatment was the only significant predictor of students' problem solving. None of the variables were significant predictors of mental model understanding. This research suggested that Piaget and Ausubel used different terminology to describe learning yet these theories are similar. Further research is needed to validate this premise and validate the blending of the two theories.

Diagnosing the influence of model structure on the simulation of water, energy and carbon fluxes on bark beetle infested forests

NASA Astrophysics Data System (ADS)

Gochis, D. J.; Gutmann, E. D.; Brooks, P. D.; Reed, D. E.; Ewers, B. E.; Pendall, E.; Biederman, J. A.; Harpold, A. A.; Barnard, H. R.; Hu, J.

2011-12-01

Forest dynamics induced by insect infestation can have a significant, local impact on plant physiological regulation of water, energy and carbon fluxes. Rapid mortality succeeded by more gradually varying land cover changes are presently thought to initiate a cascade of changes to water, energy and carbon budgets at the forest stand scale. Initial model sensitivity results have suggested very strong changes in land-atmosphere exchanges of these variables. Specifically, model results from the Noah land surface model, a relatively simple model, have suggested that loss of transpiration function may result in a nearly 50% increase in seasonal soil moisture values and similar increases in runoff production for locations in the central Rocky Mountains. However, differing model structures, such as the representation of plant canopy architecture, snowpack dynamics, dynamic vegetation and hillslope hydrologic processes, may significantly confound the synthesis of results from different modeling systems. We assess the performance of new suite of model simulations from three different land surface models of differing model structures and complexity levels against a comprehensive set of field observations of land surface flux and state variables. The focus of the analysis is in diagnosing how model structure influences changes in energy, water and carbon budget partitioning prior to and following insect infestation. Specific emphasis in this presentation is placed on verifying variables that characterize top of canopy and within canopy energy and water fluxes. We conclude the presentation with a set of recommendations about the advantages and disadvantages of various model structures in their simulation of insect driven forest dynamics.

Intercepted photosynthetically active radiation in wheat canopies estimated by spectral reflectance. [Phoenix, Arizona

NASA Technical Reports Server (NTRS)

Hatfield, J. L.; Asrar, G.; Kanemasu, E. T.

1982-01-01

The interception of photosynthetically active radiation (PAR) was evaluated relative to greenness and normalized difference (MSS 7-5/7+5) for five planting dates of wheat for 1978-79 and 1979-80 in Phoenix. Intercepted PAR was calculated from a model driven by leaf area index and stage of growth. Linear relationships were found between greenness and normalized difference with a separate model representing growth and senescence of the crop. Normalized difference was a significantly better model and would be easier to apply than the empirically derived greenness parameter. For the leaf area growth portion of the season the model between PAR interception and normalized difference was the same over years, however, for the leaf senescence the models showed more variability due to the lack of data on measured interception in sparse canopies. Normalized difference could be used to estimate PAR interception directly for crop growth models.

Appraising Birth Order in Career Assessment: Linkages to Holland's and Super's Models.

ERIC Educational Resources Information Center

Leong, Frederick T. L.; Hartung, Paul J.; Goh, David; Gaylor, Michael

2001-01-01

Study 1 (n=159) found significant differences in vocational personality types, interests, and values depending on birth order. Study 2 (n=119) found significant differences in occupational interests by birth order. Both results support Alfred Adler's theory that birth order determines aspects of vocational behavior. (Contains 33 references.) (SK)

Application of a model to analyze shoulder biomechanics in adult patients with spinal cord injury when walking with crutches in two different gait patterns.

PubMed

Perez-Rizo, Enrique; Trincado-Alonso, Fernando; Pérez-Nombela, Soraya; Del Ama-Espinosa, Antonio; Jiménez-Díaz, Fernando; Lozano-Berrio, Vicente; Gil-Agudo, Angel

2017-01-01

Specific biomechanical models have been developed to study gait using crutches. Clinical application of these models is needed in adult spinal cord injury (SCI) population walking with different patterns of gait with crutches to prevent overuse shoulder injuries. To apply a biomechanical model in a clinical environment to analyze shoulder in adult SCI patients walking with two different patterns of gait with crutches: two point reciprocal gait (RG) and swing-through gait (SG). Load cells were fixed to the distal ends and forearm cuffs of a pair of crutches. An active markers system was used for kinematics. Five cycles for each gait pattern were analyzed applying a biomechanical model of the upper limbs. Fifteen subjects with SCI were analyzed. The flexo-extension range of motion was significantly greater when using SG (p < 0.01). Similarly, the superior, posterior and medial forces were significantly stronger for SG in all 3 directions. Flexion, adduction and internal rotation torques were also greater in SG (p < 0.01). A biomechanical model was successfully applied to study shoulder biomechanics in adult patients with SCI walking with crutches in two different gait patterns. Greater loads exerted on the shoulder walking with SG were confirmed compared to RG.

Comparison of SPECT aerosol deposition data with a human respiratory tract model.

PubMed

Fleming, John S; Epps, Ben P; Conway, Joy H; Martonen, Ted B

2006-01-01

Three-dimensional (3D) radionuclide imaging provides detailed information on the distribution of inhaled aerosol material within the body. Analysis of the data can provide estimates of the deposition per airway generation. In this study, two different nebulizers have been used to deliver radiolabeled aerosols of different particle size to 12 human subjects. Medical imaging has been used to assess the deposition in the body. The deposition pattern has also been estimated using the International Commission on Radiological Protection (ICRP) empirical model and compared to values obtained by experiment. The results showed generally good agreement between model and experiment for both aerosols for the deposition in the extrathoracic and conducting airways. However, there were significant differences in the fate of the remainder of the aerosol between the amount deposited in the alveolar region and that exhaled. The inter-subject variability of deposition predicted by the model was significantly less than that measured, for all regions of the body. The model predicted quite well the differences in deposition distribution pattern between the two aerosols. In conclusion, this study has shown that the ICPR model of inhaled aerosol deposition shows areas of good agreement with results from experiment. However, there are also areas of disagreement, which may be explained by hygroscopic particle growth and individual variation in airway anatomy.

A cluster randomized theory-guided oral hygiene trial in adolescents-A latent growth model.

PubMed

Aleksejūnienė, J; Brukienė, V

2018-05-01

(i) To test whether theory-guided interventions are more effective than conventional dental instruction (CDI) for changing oral hygiene in adolescents and (ii) to examine whether such interventions equally benefit both genders and different socio-economic (SES) groups. A total of 244 adolescents were recruited from three schools, and cluster randomization allocated adolescents to one of the three types of interventions: two were theory-based interventions (Precaution Adoption Process Model or Authoritative Parenting Model) and CDI served as an active control. Oral hygiene levels % (OH) were assessed at baseline, after 3 months and after 12 months. A complete data set was available for 166 adolescents (the total follow-up rate: 69%). There were no significant differences in baseline OH between those who participated throughout the study and those who dropped out. Bivariate and multivariate analyses showed that theory-guided interventions produced significant improvements in oral hygiene and that there were no significant gender or socio-economic differences. Theory-guided interventions produced more positive changes in OH than CDI, and these changes did not differ between gender and SES groups. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Comparison of Vehicle Choice Models

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

Stephens, Thomas S.; Levinson, Rebecca S.; Brooker, Aaron

Five consumer vehicle choice models that give projections of future sales shares of light-duty vehicles were compared by running each model using the same inputs, where possible, for two scenarios. The five models compared — LVCFlex, MA3T, LAVE-Trans, ParaChoice, and ADOPT — have been used in support of the Energy Efficiency and Renewable Energy (EERE) Vehicle Technologies Office in analyses of future light-duty vehicle markets under different assumptions about future vehicle technologies and market conditions. The models give projections of sales shares by powertrain technology. Projections made using common, but not identical, inputs showed qualitative agreement, with the exception ofmore » ADOPT. ADOPT estimated somewhat lower advanced vehicle shares, mostly composed of hybrid electric vehicles. Other models projected large shares of multiple advanced vehicle powertrains. Projections of models differed in significant ways, including how different technologies penetrated cars and light trucks. Since the models are constructed differently and take different inputs, not all inputs were identical, but were the same or very similar where possible.« less

Measuring Affect, Behavior and Cognition for Modeling Disaster Risk Attitudes

DTIC Science & Technology

2012-08-15

analyze the results. The MANOVA results showed that the behavior of Malaysians towards flood differed significantly from Singaporeans, while the...during the previous decade, mainly because of two extreme events: the Indian Ocean earthquake and tsunami of 2004 and the Cyclone Nargis in Myanmar...significant at pɘ.01 From Table IV, it can be seen that the behavior of Malaysians toward flood differed significantly from Singaporeans, F

A Macaque Model for Rectal Lymphogranuloma Venereum and Non-Lymphogranuloma Venereum Chlamydia trachomatis: Impact on Rectal Simian/Human Immunodeficiency Virus Acquisition.

PubMed

Vishwanathan, Sundaram Ajay; Aubert, Rachael D; Morris, Monica R; Zhao, Chunxia; Philips, Christi; Khalil, George M; Deyounks, Frank; Kelley, Kristen; Ritter, Jana M; Chen, C Y; Kersh, Ellen N; McNicholl, Janet M

2017-09-01

Sustained genital tract inflammation caused by sexually transmitted infections (STIs) is known to increase risk of vaginal human immunodeficiency virus (HIV) infections but, to our knowledge, there are no nonhuman primate studies that have evaluated its link to rectal HIV acquisition. Rhesus macaques inoculated with Chlamydia trachomatis (CT) (serovars LGV-L2 and CT-E; n = 7) or saline (n = 7) received up to 20 rectal challenges twice a week of simian/HIV immunodeficiency virus (SHIVSF162p3). SHIV viremia was determined by real-time PCR and Chlamydia infection by APTIMA Combo 2 testing. The rectal cytokine-chemokine levels were evaluated by multiplex bead assays. Rectal Chlamydia infection was maintained throughout the study. We did not observe significant differences (P = 1.0) in frequency of SHIV acquisition between the STI and control arms. It took fewer SHIV challenges to infect the STI animals although the difference was not significant (P = 0.59). There were no significant differences in peak plasma viremia between STI and control arms (P = 0.63). The association of plasma viremia with rectal shedding was significantly different by arm (P = 0.038). In the first such study in a macaque model, we did not observe an increased risk of SHIV acquisition due to rectal Chlamydia coinfection. This macaque model can be further developed and expanded to better investigate the impact of different rectal STIs on HIV acquisition.

Direct Comparison of the Precision of the New Hologic Horizon Model With the Old Discovery Model.

PubMed

Whittaker, LaTarsha G; McNamara, Elizabeth A; Vath, Savoun; Shaw, Emily; Malabanan, Alan O; Parker, Robert A; Rosen, Harold N

2017-11-22

Previous publications suggested that the precision of the new Hologic Horizon densitometer might be better than that of the previous Discovery model, but these observations were confounded by not using the same participants and technologists on both densitometers. We sought to study this issue methodically by measuring in vivo precision in both densitometers using the same patients and technologists. Precision studies for the Horizon and Discovery models were done by acquiring spine, hip, and forearm bone mineral density twice on 30 participants. The set of 4 scans on each participant (2 on the Discovery, 2 on the Horizon) was acquired by the same technologist using the same scanning mode. The pairs of data were used to calculate the least significant change according to the International Society for Clinical Densitometry guidelines. The significance of the difference between least significant changes was assessed using a Wilcoxon signed-rank test of the difference between the mean square error of the absolute value of the differences between paired measurements on the Discovery (Δ-Discovery) and the mean square error of the absolute value of the differences between paired measurements on the Horizon (Δ-Horizon). At virtually all anatomic sites, there was a nonsignificant trend for the precision to be better for the Horizon than for the Discovery. As more vertebrae were excluded from analysis, the precision deteriorated on both densitometers. The precision between densitometers was almost identical when reporting only 1 vertebral body. (1) There was a nonsignificant trend for greater precision on the new Hologic Horizon compared with the older Discovery model. (2) The difference in precision of the spine bone mineral density between the Horizon and the Discovery models decreases as fewer vertebrae are included. (3) These findings are substantially similar to previously published results which had not controlled as well for confounding from using different subjects and technologists. Copyright © 2017 The International Society for Clinical Densitometry. Published by Elsevier Inc. All rights reserved.

Modeling temporal and spatial variability of traffic-related air pollution: Hourly land use regression models for black carbon

NASA Astrophysics Data System (ADS)

Dons, Evi; Van Poppel, Martine; Kochan, Bruno; Wets, Geert; Int Panis, Luc

2013-08-01

Land use regression (LUR) modeling is a statistical technique used to determine exposure to air pollutants in epidemiological studies. Time-activity diaries can be combined with LUR models, enabling detailed exposure estimation and limiting exposure misclassification, both in shorter and longer time lags. In this study, the traffic related air pollutant black carbon was measured with μ-aethalometers on a 5-min time base at 63 locations in Flanders, Belgium. The measurements show that hourly concentrations vary between different locations, but also over the day. Furthermore the diurnal pattern is different for street and background locations. This suggests that annual LUR models are not sufficient to capture all the variation. Hourly LUR models for black carbon are developed using different strategies: by means of dummy variables, with dynamic dependent variables and/or with dynamic and static independent variables. The LUR model with 48 dummies (weekday hours and weekend hours) performs not as good as the annual model (explained variance of 0.44 compared to 0.77 in the annual model). The dataset with hourly concentrations of black carbon can be used to recalibrate the annual model, resulting in many of the original explaining variables losing their statistical significance, and certain variables having the wrong direction of effect. Building new independent hourly models, with static or dynamic covariates, is proposed as the best solution to solve these issues. R2 values for hourly LUR models are mostly smaller than the R2 of the annual model, ranging from 0.07 to 0.8. Between 6 a.m. and 10 p.m. on weekdays the R2 approximates the annual model R2. Even though models of consecutive hours are developed independently, similar variables turn out to be significant. Using dynamic covariates instead of static covariates, i.e. hourly traffic intensities and hourly population densities, did not significantly improve the models' performance.

Influence of avian reproduction ecotoxicological endpoints in the assessment of plant protection products.

PubMed

Fernandez-Perea, M T; Prados, E Alonso; Villajos, A Novillo; Prados, J L Alonso; Baudin, J M Garcia

2009-02-01

The aim of this paper is to examine the statistical relevance of bird species on the endpoints of avian long-term toxicity studies (eggs laid, eggs set, eggs hatching, embryo survivor, 14-day old survivors and eggshell thickness). Data from 561 animals of three different species (Colinus virginianus, Anas platyrynchos and Coturnix coturnix japonica) tested with five different pesticides were analyzed in this study. The substances considered were: Thiamethoxam (EZ-3-(2-chloro-1,3-thiazol-5-ylmethyl)-5-methyl-1,3,5-oxadiazinan-4-ylidene(nitro)amine), Thiacloprid ((Z)-3-(6-chloro-3-pyridylmethyl)-1,3-thiazolidin-2-ylidenecyanamide), Acetamiprid ((E)-N(1)-[(6-chloro-3-pyridyl)methyl]-N(2)-cyano-N(1)-methylacetamidine), Phosmet (O,O-dimethyl S-phthalimidomethyl phosphorodithioate) and Dicofol (2,2,2-trichloro-1,1-bis(4-chlorophenyl)ethanol). Several general lineal mixed models were conducted to evaluate the factors affecting variables used in long-term reproductive toxicity tests. Test significance was p < 0.01 in all models tested. Model R(2) value was high (0.80) for all variables except for eggs laid (R(2) = 0.42) for the three species studied. Tukey studentized range test showed significant differences among species and pesticides. For pre-hatching period the differences were significant for eggs laid and eggs set among species. C. japonica showed statistical differences for egg hatching. With respect to embryo survivor and 14 days old survival, significant different were found for C.virginianus and A. platyrynchos, respectively. These results indicate that the selected species have an influence in the endpoints to be used for risk assessment.

A model-averaging method for assessing groundwater conceptual model uncertainty.

PubMed

Ye, Ming; Pohlmann, Karl F; Chapman, Jenny B; Pohll, Greg M; Reeves, Donald M

2010-01-01

This study evaluates alternative groundwater models with different recharge and geologic components at the northern Yucca Flat area of the Death Valley Regional Flow System (DVRFS), USA. Recharge over the DVRFS has been estimated using five methods, and five geological interpretations are available at the northern Yucca Flat area. Combining the recharge and geological components together with additional modeling components that represent other hydrogeological conditions yields a total of 25 groundwater flow models. As all the models are plausible given available data and information, evaluating model uncertainty becomes inevitable. On the other hand, hydraulic parameters (e.g., hydraulic conductivity) are uncertain in each model, giving rise to parametric uncertainty. Propagation of the uncertainty in the models and model parameters through groundwater modeling causes predictive uncertainty in model predictions (e.g., hydraulic head and flow). Parametric uncertainty within each model is assessed using Monte Carlo simulation, and model uncertainty is evaluated using the model averaging method. Two model-averaging techniques (on the basis of information criteria and GLUE) are discussed. This study shows that contribution of model uncertainty to predictive uncertainty is significantly larger than that of parametric uncertainty. For the recharge and geological components, uncertainty in the geological interpretations has more significant effect on model predictions than uncertainty in the recharge estimates. In addition, weighted residuals vary more for the different geological models than for different recharge models. Most of the calibrated observations are not important for discriminating between the alternative models, because their weighted residuals vary only slightly from one model to another.

Evaluation of the 3D Finite Element Method Using a Tantalum Rod for Osteonecrosis of the Femoral Head

PubMed Central

Shi, Jingsheng; Chen, Jie; Wu, Jianguo; Chen, Feiyan; Huang, Gangyong; Wang, Zhan; Zhao, Guanglei; Wei, Yibing; Wang, Siqun

2014-01-01

Background The aim of this study was to contrast the collapse values of the postoperative weight-bearing areas of different tantalum rod implant positions, fibula implantation, and core decompression model and to investigate the advantages and disadvantages of tantalum rod implantation in different ranges of osteonecrosis in comparison with other methods. Material/Methods The 3D finite element method was used to establish the 3D finite element model of normal upper femur, 3D finite element model after tantalum rod implantation into different positions of the upper femur in different osteonecrosis ranges, and other 3D finite element models for simulating fibula implant and core decompression. Results The collapse values in the weight-bearing area of the femoral head of the tantalum rod implant model inside the osteonecrosis area, implant model in the middle of the osteonecrosis area, fibula implant model, and shortening implant model exhibited no statistically significant differences (p>0.05) when the osteonecrosis range was small (60°). The stress values on the artificial bone surface for the tantalum rod implant model inside the osteonecrosis area and the shortening implant model exhibited statistical significance (p<0.01). Conclusions Tantalum rod implantation into the osteonecrosis area can reduce the collapse values in the weight-bearing area when osteonecrosis of the femoral head (ONFH) was in a certain range, thereby obtaining better clinical effects. When ONFH was in a large range (120°), the tantalum rod implantation inside the osteonecrosis area, shortening implant or fibula implant can reduce the collapse values of the femoral head, as assessed by other methods. PMID:25479830

Urban-rural differences in Roman Dorset, England: A bioarchaeological perspective on Roman settlements.

PubMed

Redfern, Rebecca C; DeWitte, Sharon N; Pearce, John; Hamlin, Christine; Dinwiddy, Kirsten Egging

2015-05-01

In the Roman period, urban and rural ways of living were differentiated philosophically and legally, and this is the first regional study of these contrasting life-ways. Focusing on frailty and mortality risk, we investigated how these differed by age, sex, and status, using coffin type as a proxy for social status. We employed skeletal data from 344 individuals: 150 rural and 194 urban (1st-5th centuries A.D.) from Dorset, England. Frailty and mortality risk were examined using indicators of stress (cribra orbitalia, porotic hyperostosis, nonspecific periostitis, and enamel hypoplastic defects), specific metabolic and infectious diseases (rickets, scurvy, and tuberculosis), and dental health (carious lesions and calculus). These variables were studied using Chi-square, Siler model of mortality, Kaplan-Meier analysis, and the Gompertz model of adult mortality. Our study found that overall, mortality risk and survivorship did not differ between cemetery types but when the data were examined by age, mortality risk was only significantly higher for urban subadults. Demographic differences were found, with urban cemeteries having more 0-10 and >35 year olds, and for health, urban cemeteries had significantly higher frequencies of enamel hypoplastic defects, carious lesions, and rickets. Interestingly, no significant difference in status was observed between rural and urban cemeteries. The most significant finding was the influence of the skeletal and funerary data from the Poundbury sites, which had different demographic profiles, significantly higher frequencies of the indicators of stress and dental health variables. In conclusion, there are significant health, demographic, and mortality differences between rural and urban populations in Roman Britain. © 2015 Wiley Periodicals, Inc.

A methodology for the design of experiments in computational intelligence with multiple regression models.

PubMed

Fernandez-Lozano, Carlos; Gestal, Marcos; Munteanu, Cristian R; Dorado, Julian; Pazos, Alejandro

2016-01-01

The design of experiments and the validation of the results achieved with them are vital in any research study. This paper focuses on the use of different Machine Learning approaches for regression tasks in the field of Computational Intelligence and especially on a correct comparison between the different results provided for different methods, as those techniques are complex systems that require further study to be fully understood. A methodology commonly accepted in Computational intelligence is implemented in an R package called RRegrs. This package includes ten simple and complex regression models to carry out predictive modeling using Machine Learning and well-known regression algorithms. The framework for experimental design presented herein is evaluated and validated against RRegrs. Our results are different for three out of five state-of-the-art simple datasets and it can be stated that the selection of the best model according to our proposal is statistically significant and relevant. It is of relevance to use a statistical approach to indicate whether the differences are statistically significant using this kind of algorithms. Furthermore, our results with three real complex datasets report different best models than with the previously published methodology. Our final goal is to provide a complete methodology for the use of different steps in order to compare the results obtained in Computational Intelligence problems, as well as from other fields, such as for bioinformatics, cheminformatics, etc., given that our proposal is open and modifiable.

A methodology for the design of experiments in computational intelligence with multiple regression models

PubMed Central

Gestal, Marcos; Munteanu, Cristian R.; Dorado, Julian; Pazos, Alejandro

2016-01-01

The design of experiments and the validation of the results achieved with them are vital in any research study. This paper focuses on the use of different Machine Learning approaches for regression tasks in the field of Computational Intelligence and especially on a correct comparison between the different results provided for different methods, as those techniques are complex systems that require further study to be fully understood. A methodology commonly accepted in Computational intelligence is implemented in an R package called RRegrs. This package includes ten simple and complex regression models to carry out predictive modeling using Machine Learning and well-known regression algorithms. The framework for experimental design presented herein is evaluated and validated against RRegrs. Our results are different for three out of five state-of-the-art simple datasets and it can be stated that the selection of the best model according to our proposal is statistically significant and relevant. It is of relevance to use a statistical approach to indicate whether the differences are statistically significant using this kind of algorithms. Furthermore, our results with three real complex datasets report different best models than with the previously published methodology. Our final goal is to provide a complete methodology for the use of different steps in order to compare the results obtained in Computational Intelligence problems, as well as from other fields, such as for bioinformatics, cheminformatics, etc., given that our proposal is open and modifiable. PMID:27920952

Effect of Qingnao tablet on blood viscosity of rat model of blood stasis induced by epinephrine

NASA Astrophysics Data System (ADS)

Xie, Guoqi; Hao, Shaojun; Ma, Zhenzhen; Liu, Xiaobin; Li, Jun; Li, Wenjun; Zhang, Zhengchen

2018-04-01

To establish a rat model of blood stasis with adrenaline (Adr) subcutaneous injection and ice bath stimulation. The effects of different doses on the blood viscosity of blood stasis model rats were observed. The rats were randomly divided into 6 groups: blank control group (no model), model group, positive control group, high, middle and low dose group. The whole blood viscosity and plasma viscosity were detected by blood viscosity instrument. Compared with the blank group, model group, high shear, low shear whole blood viscosity and plasma viscosity were significantly increased, TT PT significantly shortened, APTT was significantly prolonged, FIB increased significantly, indicating that the model was successful. Compared with the model group, can significantly reduce the Naoluotong group (cut, low cut). Qingnaopian high dose group (low cut), middle dose group (cut, low shear blood viscosity) (P<0.01), Can significantly reduce Naoluotong qingnaopian group, high dose group (P<0.01), plasma viscosity decreased qingnaopian plasma viscosity in low dose group (P<0.05). Conclusion: qingnaopian could improve the blood rheology of blood stasis mice abnormal index, decrease the blood viscosity, blood stasis has certain hemostatic effect.

[The metabolic profilings study of serum and spinal cord from acute spinal cord injury rats ¹H NMR spectroscopy].

PubMed

Hu, Hua-Hui; Huang, Xiao-Long; Quan, Ren-Fu; Yang, Zong-Bao; Xu, Jing-Jing

2017-02-25

To establish the rat model of acute spinal cord injury, followed by aprimary study on this model with ¹H NMR based on metabonomics and to explore the metabonomics and biomarkers of spinal cord injury rat. Twenty eight-week-old adult male SD rats of clean grade, with body weight of (200±10) g, were divided into sham operation group and model group in accordance with the law of random numbers, and every group had 10 rats. The rats of sham operation group were operated without damaging the spinal cord, and rats of model group were made an animal model of spinal cord incomplete injury according to the modified Allen's method. According to BBB score to observate the motor function of rats on the 1th, 5th, and 7th days after surgery. Postoperative spinal cord tissue was collected in order to pathologic observation at the 7th day, and the metabolic profilings of serum and spinal cord from spinal cord injury rats were studied by ¹H NMR spectroscopy. The hindlimb motion of rats did not obviously change in sham operation group, there was no significant difference at each time point;and rats of model group occurred flaccid paralysis of both lower extremities, there was a significant difference at each time; there was significant differences between two groups at each time. Pathological results showed the spinal cord structure was normal with uniform innervation in shame group, while in model group, the spinal cord structure was mussy, and the neurons were decreased, with inflammatory cells and necrotic tissue. Analysis of metabonomics showed that concentration of very low density fat protein (VLDL), low density fat protein (LDL), glutamine, citric acid, dimethylglycine (DMG) in the serum and glutathione, 3-OH-butyrate, N-Acetyl-L-aspartic acid (NAA), glycerophosphocholine (GPC), glutamic acid, and ascorbate in spinal cord had significant changes( P <0.05). There are significant differences in metabolic profile from serum and spinal cord sample between model group and sham operation group, it conduces to explain the changes of small molecular substances in serum and spinal cord tissue after spinal cord injury, this provides the research basis for targeted research on the role of metabolic markers in patients with acute spinal cord injury.

How well do the GCMs replicate the historical precipitation variability in the Colorado River Basin?

NASA Astrophysics Data System (ADS)

Guentchev, G.; Barsugli, J. J.; Eischeid, J.; Raff, D. A.; Brekke, L.

2009-12-01

Observed precipitation variability measures are compared to measures obtained using the World Climate Research Programme (WCRP) Coupled Model Intercomparison Project (CMIP3) General Circulation Models (GCM) data from 36 model projections downscaled by Brekke at al. (2007) and 30 model projections downscaled by Jon Eischeid. Three groups of variability measures are considered in this historical period (1951-1999) comparison: a) basic variability measures, such as standard deviation, interdecadal standard deviation; b) exceedance probability values, i.e., 10% (extreme wet years) and 90% (extreme dry years) exceedance probability values of series of n-year running mean annual amounts, where n=1,12; 10% exceedance probability values of annual maximum monthly precipitation (extreme wet months); and c) runs variability measures, e.g., frequency of negative and positive runs of annual precipitation amounts, total number of the negative and positive runs. Two gridded precipitation data sets produced from observations are used: the Maurer et al. (2002) and the Daly et al. (1994) Precipitation Regression on Independent Slopes Method (PRISM) data sets. The data consist of monthly grid-point precipitation averaged on a United States Geological Survey (USGS) hydrological sub-region scale. The statistical significance of the obtained model minus observed measure differences is assessed using a block bootstrapping approach. The analyses were performed on annual, seasonal and monthly scale. The results indicate that the interdecadal standard deviation is underestimated, in general, on all time scales by the downscaled model data. The differences are statistically significant at a 0.05 significance level for several Lower Colorado Basin sub-regions on annual and seasonal scale, and for several sub-regions located mostly in the Upper Colorado River Basin for the months of March, June, July and November. Although the models simulate drier extreme wet years, wetter extreme dry years and drier extreme wet months for the Upper Colorado basin, the differences are mostly not-significant. Exceptions are the results about the extreme wet years for n=3 for sub-region White-Yampa, for n=6, 7, and 8 for sub-region Upper Colorado-Dolores, and about the extreme dry years for n=11 for sub-region Great Divide-Upper Green. None of the results for the sub-regions in the Lower Colorado Basin were significant. For most of the Upper Colorado sub-regions the models simulate significantly lower frequency of negative and positive 4-6 year runs, while for several sub-regions a significantly higher frequency of 2-year negative runs is evident in the model versus the Maurer data comparisons. The model projections versus the PRISM data comparison reveals similar results for the negative runs, while for the positive runs the results indicate that the models simulate higher frequency of the 2-6 year runs. The results for the Lower Colorado basin sub-regions are similar, in general, to these for the Upper Colorado sub-regions. The differences between the simulated and the observed total number of negative or positive runs were not significant for almost all of the sub-regions within the Colorado River Basin.

A comparison of cognitive performance decreases during acute, progressive fatigue arising from different concurrent stressors.

PubMed

Fogt, Donovan L; Kalns, John E; Michael, Darren J

2010-12-01

Fatigue is known to impair cognitive performance, but it remains unclear whether concurrent common stressors affect cognitive performance similarly. We used the Stroop Color-Word Conflict Test to assess cognitive performance over 24 hours for four groups: control, sleep-deprived (SD), SD + energy deficit, and SD + energy deficit + fluid restricted. Fatigue levels were quantified using the Profile of Mood States (POMS) survey. Linear mixed-effects (LME) models allowed for testing of group-specific differences in cognitive performance while accounting for subject-level variation. Starting fatigue levels were similar among all groups, while 24-hour fatigue levels differed significantly. For each cognitive performance test, results were modeled separately. The simplest LME model contained a significant fixed-effects term for slope and intercept. Moreover, the simplest LME model used a single slope coefficient to fit data from all four groups, suggesting that loss in cognitive performance over a 24-hour duty cycle with respect to fatigue level is similar regardless of the cause.

Height-diameter allometry and above ground biomass in tropical montane forests: Insights from the Albertine Rift in Africa

PubMed Central

Boyemba, Faustin; Lewis, Simon; Nabahungu, Nsharwasi Léon; Calders, Kim; Zapfack, Louis; Riera, Bernard; Balegamire, Clarisse; Cuni-Sanchez, Aida

2017-01-01

Tropical montane forests provide an important natural laboratory to test ecological theory. While it is well-known that some aspects of forest structure change with altitude, little is known on the effects of altitude on above ground biomass (AGB), particularly with regard to changing height-diameter allometry. To address this we investigate (1) the effects of altitude on height-diameter allometry, (2) how different height-diameter allometric models affect above ground biomass estimates; and (3) how other forest structural, taxonomic and environmental attributes affect above ground biomass using 30 permanent sample plots (1-ha; all trees ≥ 10 cm diameter measured) established between 1250 and 2600 m asl in Kahuzi Biega National Park in eastern Democratic Republic of Congo. Forest structure and species composition differed with increasing altitude, with four forest types identified. Different height-diameter allometric models performed better with the different forest types, as trees got smaller with increasing altitude. Above ground biomass ranged from 168 to 290 Mg ha-1, but there were no significant differences in AGB between forests types, as tree size decreased but stem density increased with increasing altitude. Forest structure had greater effects on above ground biomass than forest diversity. Soil attributes (K and acidity, pH) also significantly affected above ground biomass. Results show how forest structural, taxonomic and environmental attributes affect above ground biomass in African tropical montane forests. They particularly highlight that the use of regional height-diameter models introduces significant biases in above ground biomass estimates, and that different height-diameter models might be preferred for different forest types, and these should be considered in future studies. PMID:28617841

Height-diameter allometry and above ground biomass in tropical montane forests: Insights from the Albertine Rift in Africa.

PubMed

Imani, Gérard; Boyemba, Faustin; Lewis, Simon; Nabahungu, Nsharwasi Léon; Calders, Kim; Zapfack, Louis; Riera, Bernard; Balegamire, Clarisse; Cuni-Sanchez, Aida

2017-01-01

Tropical montane forests provide an important natural laboratory to test ecological theory. While it is well-known that some aspects of forest structure change with altitude, little is known on the effects of altitude on above ground biomass (AGB), particularly with regard to changing height-diameter allometry. To address this we investigate (1) the effects of altitude on height-diameter allometry, (2) how different height-diameter allometric models affect above ground biomass estimates; and (3) how other forest structural, taxonomic and environmental attributes affect above ground biomass using 30 permanent sample plots (1-ha; all trees ≥ 10 cm diameter measured) established between 1250 and 2600 m asl in Kahuzi Biega National Park in eastern Democratic Republic of Congo. Forest structure and species composition differed with increasing altitude, with four forest types identified. Different height-diameter allometric models performed better with the different forest types, as trees got smaller with increasing altitude. Above ground biomass ranged from 168 to 290 Mg ha-1, but there were no significant differences in AGB between forests types, as tree size decreased but stem density increased with increasing altitude. Forest structure had greater effects on above ground biomass than forest diversity. Soil attributes (K and acidity, pH) also significantly affected above ground biomass. Results show how forest structural, taxonomic and environmental attributes affect above ground biomass in African tropical montane forests. They particularly highlight that the use of regional height-diameter models introduces significant biases in above ground biomass estimates, and that different height-diameter models might be preferred for different forest types, and these should be considered in future studies.

Acute effects of static stretching on passive stiffness of the hamstring muscles calculated using different mathematical models.

PubMed

Nordez, Antoine; Cornu, Christophe; McNair, Peter

2006-08-01

The aim of this study was to assess the effects of static stretching on hamstring passive stiffness calculated using different data reduction methods. Subjects performed a maximal range of motion test, five cyclic stretching repetitions and a static stretching intervention that involved five 30-s static stretches. A computerised dynamometer allowed the measurement of torque and range of motion during passive knee extension. Stiffness was then calculated as the slope of the torque-angle relationship fitted using a second-order polynomial, a fourth-order polynomial, and an exponential model. The second-order polynomial and exponential models allowed the calculation of stiffness indices normalized to knee angle and passive torque, respectively. Prior to static stretching, stiffness levels were significantly different across the models. After stretching, while knee maximal joint range of motion increased, stiffness was shown to decrease. Stiffness decreased more at the extended knee joint angle, and the magnitude of change depended upon the model used. After stretching, the stiffness indices also varied according to the model used to fit data. Thus, the stiffness index normalized to knee angle was found to decrease whereas the stiffness index normalized to passive torque increased after static stretching. Stretching has significant effects on stiffness, but the findings highlight the need to carefully assess the effect of different models when analyzing such data.

Predictive discomfort in single- and combined-axis whole-body vibration considering different seated postures.

PubMed

DeShaw, Jonathan; Rahmatalla, Salam

2014-08-01

The aim of this study was to develop a predictive discomfort model in single-axis, 3-D, and 6-D combined-axis whole-body vibrations of seated occupants considering different postures. Non-neutral postures in seated whole-body vibration play a significant role in the resulting level of perceived discomfort and potential long-term injury. The current international standards address contact points but not postures. The proposed model computes discomfort on the basis of static deviation of human joints from their neutral positions and how fast humans rotate their joints under vibration. Four seated postures were investigated. For practical implications, the coefficients of the predictive discomfort model were changed into the Borg scale with psychophysical data from 12 volunteers in different vibration conditions (single-axis random fore-aft, lateral, and vertical and two magnitudes of 3-D). The model was tested under two magnitudes of 6-D vibration. Significant correlations (R = .93) were found between the predictive discomfort model and the reported discomfort with different postures and vibrations. The ISO 2631-1 correlated very well with discomfort (R2 = .89) but was not able to predict the effect of posture. Human discomfort in seated whole-body vibration with different non-neutral postures can be closely predicted by a combination of static posture and the angular velocities of the joint. The predictive discomfort model can assist ergonomists and human factors researchers design safer environments for seated operators under vibration. The model can be integrated with advanced computer biomechanical models to investigate the complex interaction between posture and vibration.

Discriminating model for skin cancer diagnosis in vivo through Raman spectroscopy

NASA Astrophysics Data System (ADS)

Silveira, Fabrício Luiz; Pacheco, Marcos Tadeu T.; Bodanese, Benito; Zângaro, Renato Amaro; Silveira, Landulfo

2013-03-01

This work aimed the development of a discriminating model, using Raman spectroscopy, based on the estimated concentration of biochemical components presented in skin, for in vivo diagnosis. Raman spectra were collected in patients who underwent excision surgery of suspicious lesions at the lesion site and at a normal circumjacent site. It has been estimated the relative amount of selected biochemical compounds presented in skin. The Raman spectra of normal and malignant (basal cell carcinoma - BCC and squamous cell carcinoma - SCC) skin are quite similar, with some spectral differences in the regions of lipids, nucleic acids, and hemoglobin. Some biochemicals showed statistically significant differences among N, BCC and SCC, such as elastin, ceramide, melanin, nucleid acid, actin and phenylalanine. Elastin and ceramide presented significant differences between N and BCC, melanin, DNA and actin presented significant differences between N and BCC and between N and SCC, being melanin and DNA decreased in neoplasias, in contrast with actin, that increased in neoplasias. Concentration of phenylalanine was significantly increased for SCC compared to N and BCC. The relative concentration of melanin, DNA and phenylalanine showed sensitivity, specificity and accuracy of about 81%, 65% and 60%, respectively, using Mahalanobis distance as a discriminator. This model is being incorporated to a Raman system with automated data collection and processing that could be used for a future in vivo, real time discrimination algorithm.

Learning how the electron transport chain works: independent and interactive effects of instructional strategies and learners' characteristics.

PubMed

Darabi, Aubteen; Arrastia-Lloyd, Meagan C; Nelson, David W; Liang, Xinya; Farrell, Jennifer

2015-12-01

In order to develop an expert-like mental model of complex systems, causal reasoning is essential. This study examines the differences between forward and backward instructional strategies' in terms of efficiency, students' learning and progression of their mental models of the electronic transport chain in an undergraduate metabolism course (n = 151). Additionally, the participants' cognitive flexibility, prior knowledge, and mental effort in the learning process are also investigated. The data were analyzed using a series of general linear models to compare the strategies. Although the two strategies did not differ significantly in terms of mental model progression and learning outcomes, both groups' mental models progressed significantly. Mental effort and prior knowledge were identified as significant predictors of mental model progression. An interaction between instructional strategy and cognitive flexibility revealed that the backward instruction was more efficient than the conventional (forward) strategy for students with lower cognitive flexibility, whereas the conventional instruction was more efficient for students with higher cognitive flexibility. The results are discussed and suggestions for future research on the possible moderating role of cognitive flexibility in the area of health education are presented.

Sarcopenic obesity and overall mortality: Results from the application of novel models of body composition phenotypes to the National Health and Nutrition Examination Survey 1999-2004.

PubMed

Van Aller, Carla; Lara, Jose; Stephan, Blossom C M; Donini, Lorenzo Maria; Heymsfield, Steven; Katzmarzyk, Peter T; Wells, Jonathan C K; Prado, Carla M; Siervo, Mario

2018-02-15

There is no consensus on the definition of sarcopenic obesity (SO), resulting in inconsistent associations of SO with mortality risk. We aim to evaluate association of dual energy x-ray absorptiometry (DXA) SO models with mortality risk in a US adult population (≥50 years). The study population consisted of 3577 participants aged 50 years and older from the 1999-2004 National Health and Nutrition and Examination Survey with mortality follow-up data through December 31, 2011. Difference in survival time in people with and without SO defined by three body composition DXA models (Model 1: body composition phenotype model; Model 2: Truncal Fat Mass (TrFM)/Appendicular Skeletal Muscle Mass (ASM) ratio model; Model 3: Fat Mass (FM)/Fat Free Mass (FFM) ratio). The differences between the models were assessed by the acceleration failure time model, and expressed as time ratios (TR). Participants age 50-70 years with SO had a significantly decreased survival time, according to the body composition phenotype model (TR: 0.92; 95% CI: 0.87-0.97), and TrFM/ASM ratio model (TR: 0.88; 95% CI: 0.81-0.95). The FM/FFM ratio model did not detect significant differences in survival time. Participants with SO aged 70 years and older did not have a significantly decreased survival time, according to all three models. A SO phenotype increases mortality risk in people of age 50-70 years, but not in people aged 70 years and older. The application of the body composition phenotype and the TrFM/ASM ratio models may represent useful diagnostic approaches to improve the prediction of disease and mortality risk. Copyright © 2018 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

The AgMIP GRIDded Crop Modeling Initiative (AgGRID) and the Global Gridded Crop Model Intercomparison (GGCMI)

NASA Technical Reports Server (NTRS)

Elliott, Joshua; Muller, Christoff

2015-01-01

Climate change is a significant risk for agricultural production. Even under optimistic scenarios for climate mitigation action, present-day agricultural areas are likely to face significant increases in temperatures in the coming decades, in addition to changes in precipitation, cloud cover, and the frequency and duration of extreme heat, drought, and flood events (IPCC, 2013). These factors will affect the agricultural system at the global scale by impacting cultivation regimes, prices, trade, and food security (Nelson et al., 2014a). Global-scale evaluation of crop productivity is a major challenge for climate impact and adaptation assessment. Rigorous global assessments that are able to inform planning and policy will benefit from consistent use of models, input data, and assumptions across regions and time that use mutually agreed protocols designed by the modeling community. To ensure this consistency, large-scale assessments are typically performed on uniform spatial grids, with spatial resolution of typically 10 to 50 km, over specified time-periods. Many distinct crop models and model types have been applied on the global scale to assess productivity and climate impacts, often with very different results (Rosenzweig et al., 2014). These models are based to a large extent on field-scale crop process or ecosystems models and they typically require resolved data on weather, environmental, and farm management conditions that are lacking in many regions (Bondeau et al., 2007; Drewniak et al., 2013; Elliott et al., 2014b; Gueneau et al., 2012; Jones et al., 2003; Liu et al., 2007; M¨uller and Robertson, 2014; Van den Hoof et al., 2011;Waha et al., 2012; Xiong et al., 2014). Due to data limitations, the requirements of consistency, and the computational and practical limitations of running models on a large scale, a variety of simplifying assumptions must generally be made regarding prevailing management strategies on the grid scale in both the baseline and future periods. Implementation differences in these and other modeling choices contribute to significant variation among global-scale crop model assessments in addition to differences in crop model implementations that also cause large differences in site-specific crop modeling (Asseng et al., 2013; Bassu et al., 2014).

Study on perfume stimulating olfaction with volatile oil of Acorus gramineus for treatment of the Alzheimer's disease rat.

PubMed

Liu, Zhi-Bin; Niu, Wen-Min; Yang, Xiao-Hang; Wang, Yuan; Wang, Wei-Gang

2010-12-01

To probe into the therapeutic effect of perfume stimulating olfaction with volatile oil of Acorus Gramineus on the Alzheimer's disease (AD) rat. Totally 50 adult SD rats, male,weighing 300 +/- 10 g, were randomly divided into 5 groups, normal group (group A), olfactory nerve severing model group (group B), AD model group (group C), AD model plus perfume stimulation group (group D), AD model olfactory nerve severing plus perfume stimulation group (group E), 10 rats in each group. After perfume stimulation, Morris maze test was conducted for valuating the learning and memory ability; Malondaldehyde (MDA) content, and superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities in the brain, and the brain weight were detected. Compared with the AD model group, the average escape latency and swimming distance in 6 days were significantly shorter than those in the group A, B, D (P < 0.01), with no significant differences between the group C and the group E (P > 0.05); Compared with the group A, B and D, MDA content in the group C significantly increased (P < 0.01), and SOD and GSH-Px activities significantly decreased (P < 0.01), and brain weight/body weight decreased significantly in the group C (P < 0.01), with no significant differences between the group C and the group E (P > 0.05). Perfume stimultating olfaction with volatile oil of Acorus Gramineus can significantly increase the learning-memory ability, decrease MDA content and increase SOD and GSH-Px activities and weight of brain in AD rats.

[Mechanism study on leptin resistance in lung cancer cachexia rats treated by Xiaoyan Decoction].

PubMed

Zhang, Yun-Chao; Jia, Ying-Jie; Yang, Pei-Ying; Zhang, Xing; Li, Xiao-Jiang; Zhang, Ying; Zhu, Jin-Li; Sun, Yi-Yu; Chen, Jun; Duan, Hao-Guo; Guo, Hua; Li, Chao

2014-12-01

To study the leptin resistance mechanism of Xiaoyan Decoction (XD) in lung cancer cachexia (LCC) rats. An LCC rat model was established. Totally 40 rats were randomly divided into the normal control group, the LCC model group, the XD group, and the positive control group, 10 in each group. After LCC model was set up, rats in the LCC model group were administered with normal saline, 2 mL each time. Rats in the XD group were administered with XD at the daily dose of 2 mL. Those in the positive control group were administered with Medroxyprogesterone Acetate suspension (20 mg/kg) by gastrogavage at the daily dose of 2 mL. All medication lasted for 14 days. The general condition and tumor growth were observed. Serum levels of leptin and leptin receptor in the hypothalamus were detected using enzyme-linked immunosorbent assay. Contents of neuropeptide Y (NPY) and anorexia for genomic POMC were detected using real-time PCR technique. Serum leptin levels were lower in the LCC model group than in the normal control group with statistical significance (P < 0.05). Compared with the LCC model groups, serum leptin levels significantly increased in the XD group (P < 0.01). Leptin receptor levels in the hypothalamus increased significantly in the LCC model group (P < 0.01). Increased receptor levels in the LCC model group indicated that either XD or Medroxyprogesterone Acetate could effectively reduce levels of leptin receptor with statistical significance (P < 0.01). There was also statistical difference between the XD group and the positive control group (P < 0.05). Contents of NPY was higher in the LCC model group than in the other groups with statistical difference (P < 0.05). There was no statistical difference in NPY between the normal control group and the rest 2 treatment groups (P > 0.05). There was statistical difference in POMC between the normal control group and the LCC model group (P < 0.05). POMC could be decreased in the XD group and the positive control group with statistical significance (P < 0.05), and it was more obviously decreased in the XD group (P < 0.05). Leptin resistance existed in LCC rats. XD could increase serum leptin levels and reduce leptin receptor levels in the hypothalamus. LCC could be improved by elevating NPY contents in the hypothalamus and reducing POMC contents, promoting the appetite, and increasing food intake from the periphery pathway and the central pathway.

Assessing in vivo fertilizing capacity of liquid-preserved boar semen according to the 'Hanover gilt model'.

PubMed

Ardón, F; Döhring, A; Le Thi, X; Weitze, K F; Waberski, D

2003-04-01

The goal of this study was to determine the ability of the Hanover gilt model to assess in vivo fertilizing capacity of preserved sperm and to consider whether any modifications to this model were needed. This model evaluates the fertilizing capacity of semen based on the fertilization rate, the rate of normal embryos and the accessory sperm count of 3-5-day embryos. Its distinguishing characteristics are the use of one-time insemination of sperm in reduced numbers, of spontaneously ovulating gilts and of ovulation detection through ultrasound examination of ovaries. Reduced sperm numbers allow for an accurate evaluation of the fertilizing potential of different semen treatments, thereby avoiding the compensatory effect of doses calibrated to maximize fertility. The model's usefulness was assessed in a trial run designed to compare the fertilizing capacity of liquid boar semen diluted into two different extenders. The diluent, the boar and the backflow, had no significant effect on any of the parameters studied. Gilts inseminated less than 24 h before ovulation had a significantly higher (p < 0.01) fertilization rate and accessory sperm cell count (p < 0.05) than those inseminated more than 24 h before ovulation. Very good/good embryos from homogeneous litters (only very good/good embryos were present) had a significantly higher (p < 0.01) accessory sperm count than those from heterogeneous litters (at least one embryo was of a different quality and/or oocytes were present). Both very good/good and degenerated/retarded embryos from heterogeneous litters had low accessory sperm numbers. This suggests that accessory sperm count is significantly related to the quality of the litter, but not to the quality of the embryo within gilts. It can be concluded that the Hanover gilt model is sensitive enough to show fertility differences (in this study, those associated with in vivo ageing of semen), while using relatively few gilts and little time.

An Intercomparison of 2-D Models Within a Common Framework

NASA Technical Reports Server (NTRS)

Weisenstein, Debra K.; Ko, Malcolm K. W.; Scott, Courtney J.; Jackman, Charles H.; Fleming, Eric L.; Considine, David B.; Kinnison, Douglas E.; Connell, Peter S.; Rotman, Douglas A.; Bhartia, P. K. (Technical Monitor)

2002-01-01

A model intercomparison among the Atmospheric and Environmental Research (AER) 2-D model, the Goddard Space Flight Center (GSFC) 2-D model, and the Lawrence Livermore National Laboratory 2-D model allows us to separate differences due to model transport from those due to the model's chemical formulation. This is accomplished by constructing two hybrid models incorporating the transport parameters of the GSFC and LLNL models within the AER model framework. By comparing the results from the native models (AER and e.g. GSFC) with those from the hybrid model (e.g. AER chemistry with GSFC transport), differences due to chemistry and transport can be identified. For the analysis, we examined an inert tracer whose emission pattern is based on emission from a High Speed Civil Transport (HSCT) fleet; distributions of trace species in the 2015 atmosphere; and the response of stratospheric ozone to an HSCT fleet. Differences in NO(y) in the upper stratosphere are found between models with identical transport, implying different model representations of atmospheric chemical processes. The response of O3 concentration to HSCT aircraft emissions differs in the models from both transport-dominated differences in the HSCT-induced perturbations of H2O and NO(y) as well as from differences in the model represent at ions of O3 chemical processes. The model formulations of cold polar processes are found to be the most significant factor in creating large differences in the calculated ozone perturbations

A comparative study of manhole hydraulics using stereoscopic PIV and different RANS models.

PubMed

Beg, Md Nazmul Azim; Carvalho, Rita F; Tait, Simon; Brevis, Wernher; Rubinato, Matteo; Schellart, Alma; Leandro, Jorge

2017-04-01

Flows in manholes are complex and may include swirling and recirculation flow with significant turbulence and vorticity. However, how these complex 3D flow patterns could generate different energy losses and so affect flow quantity in the wider sewer network is unknown. In this work, 2D3C stereo Particle Image Velocimetry measurements are made in a surcharged scaled circular manhole. A computational fluid dynamics (CFD) model in OpenFOAM ® with four different Reynolds Averaged Navier Stokes (RANS) turbulence model is constructed using a volume of fluid model, to represent flows in this manhole. Velocity profiles and pressure distributions from the models are compared with the experimental data in view of finding the best modelling approach. It was found among four different RANS models that the re-normalization group (RNG) k-ɛ and k-ω shear stress transport (SST) gave a better approximation for velocity and pressure.

Comparison of catch per unit effort among four minnow trap models in the three-spined stickleback (Gasterosteus aculeatus) fishery.

PubMed

Budria, Alexandre; DeFaveri, Jacquelin; Merilä, Juha

2015-12-21

Minnow traps are commonly used in the stickleback (Gasterostidae) fishery, but the potential differences in catch per unit effort (CPUE) among different minnow trap models are little studied. We compared the CPUE of four different minnow trap models in field experiments conducted with three-spined sticklebacks (Gasterosteus aculeatus). Marked (up to 26 fold) differences in median CPUE among different trap models were observed. Metallic uncoated traps yielded the largest CPUE (2.8 fish/h), followed by metallic black nylon-coated traps (1.3 fish/h). Collapsible canvas traps yielded substantially lower CPUEs (black: 0.7 fish/h; red: 0.1 fish/h) than the metallic traps. Laboratory trials further revealed significant differences in escape probabilities among the different trap models. While the differences in escape probability can explain at least part of the differences in CPUE among the trap models (e.g. high escape rate and low CPUE in red canvas traps), discrepancies between model-specific CPUEs and escape rates suggests that variation in entrance rate also contributes to the differences in CPUE. In general, and in accordance with earlier data on nine-spined stickleback (Pungitius pungitius) trapping, the results suggest that uncoated metallic (Gee-type) traps are superior to the other commonly used minnow trap models in stickleback fisheries.

Comparison of catch per unit effort among four minnow trap models in the three-spined stickleback (Gasterosteus aculeatus) fishery

PubMed Central

Budria, Alexandre; DeFaveri, Jacquelin; Merilä, Juha

2015-01-01

Minnow traps are commonly used in the stickleback (Gasterostidae) fishery, but the potential differences in catch per unit effort (CPUE) among different minnow trap models are little studied. We compared the CPUE of four different minnow trap models in field experiments conducted with three-spined sticklebacks (Gasterosteus aculeatus). Marked (up to 26 fold) differences in median CPUE among different trap models were observed. Metallic uncoated traps yielded the largest CPUE (2.8 fish/h), followed by metallic black nylon-coated traps (1.3 fish/h). Collapsible canvas traps yielded substantially lower CPUEs (black: 0.7 fish/h; red: 0.1 fish/h) than the metallic traps. Laboratory trials further revealed significant differences in escape probabilities among the different trap models. While the differences in escape probability can explain at least part of the differences in CPUE among the trap models (e.g. high escape rate and low CPUE in red canvas traps), discrepancies between model-specific CPUEs and escape rates suggests that variation in entrance rate also contributes to the differences in CPUE. In general, and in accordance with earlier data on nine-spined stickleback (Pungitius pungitius) trapping, the results suggest that uncoated metallic (Gee-type) traps are superior to the other commonly used minnow trap models in stickleback fisheries. PMID:26685761

The cognitive processes underlying event-based prospective memory in school-age children and young adults: a formal model-based study.

PubMed

Smith, Rebekah E; Bayen, Ute J; Martin, Claudia

2010-01-01

Fifty children 7 years of age (29 girls, 21 boys), 53 children 10 years of age (29 girls, 24 boys), and 36 young adults (19 women, 17 men) performed a computerized event-based prospective memory task. All 3 groups differed significantly in prospective memory performance, with adults showing the best performance and with 7-year-olds showing the poorest performance. We used a formal multinomial process tree model of event-based prospective memory to decompose age differences in cognitive processes that jointly contribute to prospective memory performance. The formal modeling results demonstrate that adults differed significantly from the 7-year-olds and the 10-year-olds on both the prospective component and the retrospective component of the task. The 7-year-olds and the 10-year-olds differed only in the ability to recognize prospective memory target events. The prospective memory task imposed a cost to ongoing activities in all 3 age groups. Copyright 2009 APA, all rights reserved.

ART, Stoffenmanager, and TRA: A Systematic Comparison of Exposure Estimates Using the TREXMO Translation System.

PubMed

Savic, Nenad; Gasic, Bojan; Vernez, David

2017-12-15

Several occupational exposure models are recommended under the EU's REACH legislation. Due to limited availability of high-quality exposure data, their validation is an ongoing process. It was shown, however, that different models may calculate significantly different estimates and thus lead to potentially dangerous conclusions about chemical risk. In this paper, the between-model translation rules defined in TREXMO were used to generate 319000 different in silico exposure situations in ART, Stoffenmanager, and ECETOC TRA v3. The three models' estimates were computed and the correlation and consistency between them were investigated. The best correlated pair was Stoffenmanager-ART (R, 0.52-0.90), whereas the ART-TRA and Stoffenmanager-TRA correlations were either lower (R, 0.36-0.69) or no correlation was found. Consistency varied significantly according to different exposure types (e.g. vapour versus dust) or settings (near-field versus far-field and indoors versus outdoors). The percentages of generated situations for which estimates differed by more than a factor of 100 ranged from 14 to 97%, 37 to 99%, and 1 to 68% for Stoffenmanager-ART, TRA-ART, and TRA-Stoffenmanager, respectively. Overall, the models were more consistent for vapours than for dusts and solids, near-fields than for far-fields, and indoor than for outdoor exposure. Multiple linear regression analyses evidenced the relationship between the models' parameters and the relative differences between the models' predictions. The relative difference can be used to estimate the consistency between the models. Furthermore, the study showed that the tiered approach is not generally applicable to all exposure situations. These findings emphasize the need for a multiple-model approach to assessing critical exposure scenarios under REACH. Moreover, in combination with occupational exposure measurements, they might also be used for future studies to improve prediction accuracy. © The Author(s) 2017. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

Variation in Airway Responsiveness of Male C57BL/6 Mice from 5 Vendors

PubMed Central

Chang, Herng-Yu Sucie; Mitzner, Wayne; Watson, Julie

2012-01-01

Mice are now the most commonly used animal model for the study of asthma. The mouse asthma model has many characteristics of the human pathology, including allergic sensitization and airway hyperresponsiveness. Inbred strains are commonly used to avoid variations due to genetic background, but variations due to rearing environment are not as well recognized. After a change in mouse vendors and a switch from C57BL/6J mice to C57BL/6N mice, we noted significant differences in airway responsiveness between the substrains. To further investigate the effect of vendor, we tested C57BL/6N mice from 3 other vendors and found significant differences between several of the substrains. To test whether this difference was due to genetic drift or rearing environment, we purchased new groups of mice from all 5 vendors, bred them in separate vendor-specific groups under uniform environmental conditions, and tested male first generation (F1) offspring at 8 to 10 wk of age. These F1 mice showed no significant differences in airway responsiveness, indicating that the rearing environment rather than genetic differences was responsible for the initial variation in pulmonary phenotype. The environmental factors that caused the phenotypic variation are unknown. However, differences between vendor in feed components, bedding type, or microbiome could have contributed. Whatever the basis, investigators using mouse models of asthma should be cautious in comparing data from mice obtained from different vendors. PMID:23043804

The Sport Participation Model Questionnaire: A Tool for the Assessment of Sport Orientations

ERIC Educational Resources Information Center

Aicinena, Steve; Eldridge, James

2006-01-01

The Sport Participation Model Questionnaire (SPMQ) was given to two hundred and sixty-four subjects to determine if significant differences existed in the composite scores of parents, coaches, youth sport participants, high school participants and college students; if the groups differed in their responses to pooled items; and if subject groups…

3D Printout Models vs. 3D-Rendered Images: Which Is Better for Preoperative Planning?

PubMed

Zheng, Yi-xiong; Yu, Di-fei; Zhao, Jian-gang; Wu, Yu-lian; Zheng, Bin

2016-01-01

Correct interpretation of a patient's anatomy and changes that occurs secondary to a disease process are crucial in the preoperative process to ensure optimal surgical treatment. In this study, we presented 3 different pancreatic cancer cases to surgical residents in the form of 3D-rendered images and 3D-printed models to investigate which modality resulted in the most appropriate preoperative plan. We selected 3 cases that would require significantly different preoperative plans based on key features identifiable in the preoperative computed tomography imaging. 3D volume rendering and 3D printing were performed respectively to create 2 different training ways. A total of 30, year 1 surgical residents were randomly divided into 2 groups. Besides traditional 2D computed tomography images, residents in group A (n = 15) reviewed 3D computer models, whereas in group B, residents (n = 15) reviewed 3D-printed models. Both groups subsequently completed an examination, designed in-house, to assess the appropriateness of their preoperative plan and provide a numerical score of the quality of the surgical plan. Residents in group B showed significantly higher quality of the surgical plan scores compared with residents in group A (76.4 ± 10.5 vs. 66.5 ± 11.2, p = 0.018). This difference was due in large part to a significant difference in knowledge of key surgical steps (22.1 ± 2.9 vs. 17.4 ± 4.2, p = 0.004) between each group. All participants reported a high level of satisfaction with the exercise. Results from this study support our hypothesis that 3D-printed models improve the quality of surgical trainee's preoperative plans. Copyright © 2016 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

Study on the effects of blueberry treatment on histone acetylation modification of CCl4-induced liver disease in rats.

PubMed

Zhan, W; Liao, X; Tian, T; Yu, L; Liu, X; Li, B; Liu, J; Han, B; Xie, R J; Ji, Q H; Yang, Q

2017-02-16

The objective of this study was to investigate the effects of blueberry treatment on histone acetylation modification of carbon tetrachloride (CCl 4 )-induced liver disease in rats. Laboratory rats were randomly divided into control, hepatic fibrosis, blueberry treatment, blueberry intervention, and natural recovery groups. Rats in the model groups were treated with CCl 4 administered subcutaneously at 4- and 8-week intervals, and then executed. Both the 4- and 8-week treatment groups were treated with blueberry juice for 8 weeks, and then executed after 12 and 16 weeks, respectively. Following the experiment, four liver function and hepatic fibrosis indices were measured. Liver index was calculated, hematoxylin-eosin staining was conducted, and H3K9, H3K14, and H3K18 expressions were evaluated among the nuclear proteins of the liver tissues. No differences in alanine transaminase were noted between the control and intervention groups, but significant differences were detected among the model, treatment, and natural recovery groups (P < 0.01). Significant differences were also observed in aspartate transaminase, hyaluronic acid, and collagen IV among the model, treatment, intervention, and natural recovery groups (P < 0.01, P < 0.01, P < 0.01). Liver index, and H3K9 and H3K14 expression were significantly different among the model groups (P < 0.05 and P < 0.01), whereas H3K18 expression was dramatically different among model, treatment, intervention, and natural recovery groups (P < 0.01). Following blueberry treatment, rat liver function and hepatic fibrosis improved, potentially indicating that blueberry components could regulate histone acetylation and improve liver pathologic changes in rats with CCl 4 -induced disease.

Possibilities of rock constitutive modelling and simulations

NASA Astrophysics Data System (ADS)

Baranowski, Paweł; Małachowski, Jerzy

2018-01-01

The paper deals with a problem of rock finite element modelling and simulation. The main intention of authors was to present possibilities of different approaches in case of rock constitutive modelling. For this purpose granite rock was selected, due to its wide mechanical properties recognition and prevalence in literature. Two significantly different constitutive material models were implemented to simulate the granite fracture in various configurations: Johnson - Holmquist ceramic model which is very often used for predicting rock and other brittle materials behavior, and a simple linear elastic model with a brittle failure which can be used for simulating glass fracturing. Four cases with different loading conditions were chosen to compare the aforementioned constitutive models: uniaxial compression test, notched three-point-bending test, copper ball impacting a block test and small scale blasting test.

On fitting generalized linear mixed-effects models for binary responses using different statistical packages.

PubMed

Zhang, Hui; Lu, Naiji; Feng, Changyong; Thurston, Sally W; Xia, Yinglin; Zhu, Liang; Tu, Xin M

2011-09-10

The generalized linear mixed-effects model (GLMM) is a popular paradigm to extend models for cross-sectional data to a longitudinal setting. When applied to modeling binary responses, different software packages and even different procedures within a package may give quite different results. In this report, we describe the statistical approaches that underlie these different procedures and discuss their strengths and weaknesses when applied to fit correlated binary responses. We then illustrate these considerations by applying these procedures implemented in some popular software packages to simulated and real study data. Our simulation results indicate a lack of reliability for most of the procedures considered, which carries significant implications for applying such popular software packages in practice. Copyright © 2011 John Wiley & Sons, Ltd.

[Carbon Source Utilization Characteristics of Soil Microbial Community for Apple Orchard with Interplanting Herbage].

PubMed

Du, Yi-fei; Fang, Kai-kai; Wang, Zhi-kang; Li, Hui-ke; Mao, Peng-juan; Zhang, Xiang-xu; Wang, Jing

2015-11-01

As soil fertility in apple orchard with clean tillage is declined continuously, interplanting herbage in orchard, which is a new orchard management model, plays an important role in improving orchard soil conditions. By using biolog micro-plate technique, this paper studied the functional diversity of soil microbial community under four species of management model in apple orchards, including clear tillage model, interplanting white clover model, interplanting small crown flower model and interplanting cocksfoot model, and the carbon source utilization characteristics of microbial community were explored, which could provide a reference for revealing driving mechanism of ecological process of orchard soil. The results showed that the functional diversity of microbial community had a significant difference among different treatments and in the order of white clover > small crown flower > cocksfoot > clear tillage. The correlation analysis showed that the average well color development (AWCD), Shannon index, Richness index and McIntosh index were all highly significantly positively correlated with soil organic carbon, total nitrogen, microbial biomass carbon, and Shannon index was significantly positively correlated with soil pH. The principal component analysis and the fingerprints of the physiological carbon metabolism of the microbial community demonstrated that grass treatments improved carbon source metabolic ability of soil microbial community, and the soil microbes with perennial legumes (White Clover and small crown flower) had a significantly higher utilization rate in carbohydrates (N-Acetyl-D-Glucosamine, D-Mannitol, β-Methyl-D-Glucoside), amino acids (Glycyl-L-Glutamic acid, L-Serine, L-Threonine) and polymers (Tween 40, Glycogen) than the soil microbes with clear tillage. It was considered that different treatments had the unique microbial community structure and peculiar carbon source utilization characteristics.

Adventitial nab-rapamycin injection reduces porcine femoral artery luminal stenosis induced by balloon angioplasty via inhibition of medial proliferation and adventitial inflammation.

PubMed

Gasper, Warren J; Jimenez, Cynthia A; Walker, Joy; Conte, Michael S; Seward, Kirk; Owens, Christopher D

2013-12-01

Endovascular interventions on peripheral arteries are limited by high rates of restenosis. Our hypothesis was that adventitial injection of rapamycin nanoparticles would be safe and reduce luminal stenosis in a porcine femoral artery balloon angioplasty model. Eighteen juvenile male crossbred swine were included. Single-injury (40%-60% femoral artery balloon overstretch injury; n=2) and double-injury models (endothelial denudation injury 2 weeks before a 20%-30% overstretch injury; n=2) were compared. The double-injury model produced significantly more luminal stenosis at 28 days, P=0.002, and no difference in medial fibrosis or inflammation. Four pigs were randomized to the double-injury model and adventitial injection of saline (n=2) or 500 μg of nanoparticle albumin-bound rapamycin (nab-rapamycin; n=2) with an endovascular microinfusion catheter. There was 100% procedural success and no difference in endothelial regeneration. At 28 days, nab-rapamycin led to significant reductions in luminal stenosis, 17% (interquartile range, 12%-35%) versus 10% (interquartile range, 8.3%-14%), P=0.001, medial cell proliferation, P<0.001, and fibrosis, P<0.001. There were significantly fewer adventitial leukocytes at 3 days, P<0.001, but no difference at 28 days. Pharmacokinetic analysis (single-injury model) found rapamycin concentrations 1500× higher in perivascular tissues than in blood at 1 hour. Perivascular rapamycin persisted ≥8 days and was not detectable at 28 days. Adventitial nab-rapamycin injection was safe and significantly reduced luminal stenosis in a porcine femoral artery balloon angioplasty model. Observed reductions in early adventitial leukocyte infiltration and late medial cell proliferation and fibrosis suggest an immunosuppressive and antiproliferative mechanism. An intraluminal microinfusion catheter for adventitial injection represents an alternative to stent- or balloon-based local drug delivery.

Exploring a Dynamic Model of Trust Management

DTIC Science & Technology

2014-06-01

individualists whereby their satisfaction towards business negotiation stems mainly from high economic gains or personal outcomes. Therefore, it...undergraduate business students. No significant differences were found in the extent to which Canadian and Japanese trustors rely on dispositional signs...analytic- holism scale signifies high level of holism. No statistically significant difference was found between Malays, Chinese, and Indians on the

Accuracy of single-abutment digital cast obtained using intraoral and cast scanners.

PubMed

Lee, Jae-Jun; Jeong, Ii-Do; Park, Jin-Young; Jeon, Jin-Hun; Kim, Ji-Hwan; Kim, Woong-Chul

2017-02-01

Scanners are frequently used in the fabrication of dental prostheses. However, the accuracy of these scanners is variable, and little information is available. The purpose of this in vitro study was to compare the accuracy of cast scanners with that of intraoral scanners by using different image impression techniques. A poly(methyl methacrylate) master model was fabricated to replicate a maxillary first molar single-abutment tooth model. The master model was scanned with an accurate engineering scanner to obtain a true value (n=1) and with 2 intraoral scanners (CEREC Bluecam and CEREC Omnicam; n=6 each). The cast scanner scanned the master model and duplicated the dental stone cast from the master model (n=6). The trueness and precision of the data were measured using a 3-dimensional analysis program. The Kruskal-Wallis test was used to compare the different sets of scanning data, followed by a post hoc Mann-Whitney U test with a significance level modified by Bonferroni correction (α/6=.0083). The type 1 error level (α) was set at .05. The trueness value (root mean square: mean ±standard deviation) was 17.5 ±1.8 μm for the Bluecam, 13.8 ±1.4 μm for the Omnicam, 17.4 ±1.7 μm for cast scanner 1, and 12.3 ±0.1 μm for cast scanner 2. The differences between the Bluecam and the cast scanner 1 and between the Omnicam and the cast scanner 2 were not statistically significant (P>.0083), but a statistically significant difference was found between all the other pairs (P<.0083). The precision of the scanners was 12.7 ±2.6 μm for the Bluecam, 12.5 ±3.7 μm for the Omnicam, 9.2 ±1.2 μm for cast scanner 1, and 6.9 ±2.6 μm for cast scanner 2. The differences between Bluecam and Omnicam and between Omnicam and cast scanner 1 were not statistically significant (P>.0083), but there was a statistically significant difference between all the other pairs (P<.0083). An Omnicam in video image impression had better trueness than a cast scanner but with a similar level of precision. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Cognitive vulnerability to depression in Canadian and Chinese adolescents.

PubMed

Auerbach, Randy P; Eberhart, Nicole K; Abela, John R Z

2010-01-01

The goal of the current study was to compare diathesis-stress and transactional models of cognitive vulnerability to depression in samples of Canadian (n = 118) and Chinese (n = 405) adolescents. We utilized a six-month multi-wave, longitudinal design in order to examine whether (a) perceived control moderated the association between the occurrence of dependent interpersonal stressors and subsequent increases in depressive symptoms (i.e., a diathesis-stress perspective) and (b) dependent interpersonal stressors mediated the association between perceived control and subsequent increases in depressive symptoms (i.e., a transactional perspective). Results from idiographic, time-lagged, hierarchical linear modeling analyses indicated that for Canadian adolescents both diathesis-stress and transactional models were significant predictors of depressive symptomology. When examining the diathesis-stress model, boys, but not girls, who reported lower perceived control, reported higher levels of depressive symptoms following the occurrence of dependent interpersonal stress. Gender differences, however, were not present in the transactional model. In contrast, transactional, but not diathesis-stress, models were significant in Chinese adolescents, and gender differences did not emerge. Overall, these results may reflect culturally-relevant differences in the etiology of depression in Canadian and Chinese adolescents.

Development of a real-time crash risk prediction model incorporating the various crash mechanisms across different traffic states.

PubMed

Xu, Chengcheng; Wang, Wei; Liu, Pan; Zhang, Fangwei

2015-01-01

This study aimed to identify the traffic flow variables contributing to crash risks under different traffic states and to develop a real-time crash risk model incorporating the varying crash mechanisms across different traffic states. The crash, traffic, and geometric data were collected on the I-880N freeway in California in 2008 and 2009. This study considered 4 different traffic states in Wu's 4-phase traffic theory. They are free fluid traffic, bunched fluid traffic, bunched congested traffic, and standing congested traffic. Several different statistical methods were used to accomplish the research objective. The preliminary analysis showed that traffic states significantly affected crash likelihood, collision type, and injury severity. Nonlinear canonical correlation analysis (NLCCA) was conducted to identify the underlying phenomena that made certain traffic states more hazardous than others. The results suggested that different traffic states were associated with various collision types and injury severities. The matching of traffic flow characteristics and crash characteristics in NLCCA revealed how traffic states affected traffic safety. The logistic regression analyses showed that the factors contributing to crash risks were quite different across various traffic states. To incorporate the varying crash mechanisms across different traffic states, random parameters logistic regression was used to develop a real-time crash risk model. Bayesian inference based on Markov chain Monte Carlo simulations was used for model estimation. The parameters of traffic flow variables in the model were allowed to vary across different traffic states. Compared with the standard logistic regression model, the proposed model significantly improved the goodness-of-fit and predictive performance. These results can promote a better understanding of the relationship between traffic flow characteristics and crash risks, which is valuable knowledge in the pursuit of improving traffic safety on freeways through the use of dynamic safety management systems.

A hybrid genetic algorithm-queuing multi-compartment model for optimizing inpatient bed occupancy and associated costs.

PubMed

Belciug, Smaranda; Gorunescu, Florin

2016-03-01

Explore how efficient intelligent decision support systems, both easily understandable and straightforwardly implemented, can help modern hospital managers to optimize both bed occupancy and utilization costs. This paper proposes a hybrid genetic algorithm-queuing multi-compartment model for the patient flow in hospitals. A finite capacity queuing model with phase-type service distribution is combined with a compartmental model, and an associated cost model is set up. An evolutionary-based approach is used for enhancing the ability to optimize both bed management and associated costs. In addition, a "What-if analysis" shows how changing the model parameters could improve performance while controlling costs. The study uses bed-occupancy data collected at the Department of Geriatric Medicine - St. George's Hospital, London, period 1969-1984, and January 2000. The hybrid model revealed that a bed-occupancy exceeding 91%, implying a patient rejection rate around 1.1%, can be carried out with 159 beds plus 8 unstaffed beds. The same holding and penalty costs, but significantly different bed allocations (156 vs. 184 staffed beds, and 8 vs. 9 unstaffed beds, respectively) will result in significantly different costs (£755 vs. £1172). Moreover, once the arrival rate exceeds 7 patient/day, the costs associated to the finite capacity system become significantly smaller than those associated to an Erlang B queuing model (£134 vs. £947). Encoding the whole information provided by both the queuing system and the cost model through chromosomes, the genetic algorithm represents an efficient tool in optimizing the bed allocation and associated costs. The methodology can be extended to different medical departments with minor modifications in structure and parameterization. Copyright © 2016 Elsevier B.V. All rights reserved.

Regulation of organic nucleic acids and serum biochemistry parameters by dietary chromium picolinate supplementation in swine model.

PubMed

Jiajun, Yang; Aiyun, Han; Shanshan, Zheng; Minhong, Zhang

2011-04-01

The relationships between chromium and metabolism are sophisticated. Organic nucleic acids and serum biochemistry parameters are affected by dietary chromium levels. The objective of this work was to study the effect of chromium picolinate (CrPic) supplementation on total DNA and RNA contents, the ratio of RNA/DNA in muscle and in pancreatic tissue, the level of insulin receptor (IR) mRNA and some serum biochemistry parameters in a porcine model. Young animals (48) were assigned randomly into three groups of 16 piglets, fed with three different dietary levels of Cr (common basal feedstuff alone or supplemented with CrPic at a dose of 1.61 μg/g or 3.22 μg/g, which corresponds to 0.2 μg/g and 0.4 μg/g Cr). After 80 days, the animals were sacrificed and skeletal muscle and pancreatic tissues were analyzed to detect differences caused by different levels of dietary Cr. The total content of RNA in muscle was increased significantly (P<0.05) in the CrPic supplemented groups. There was no significant difference between groups in the concentrations of total RNA in the pancreas or DNA in the muscle and pancreatic tissues. The RNA/DNA ratio in pancreas showed no significant change but the ratio was increased significantly (P<0.05) in muscle. There was a slight increase of the mRNA level of IR but there was no significant difference between groups. The content of serum cholesterol and insulin were reduced significantly (P<0.05) in the CrPic-supplemented groups and the content of high-density lipoprotein cholesterol (HDLC) was increased significantly (P<0.05) as the CrPic dose increased. There was a slight (non-significant) reduction of the concentrations of serum triglyceride and low-density lipoprotein cholesterol (LDLC) in the CrPic supplementation groups. Supplementary CrPic caused no significant change of muscular mRNA level of IR in healthy animals. An increased content of RNA in muscle, improved cholesterol metabolism and improved insulin sensitivity were found in these CrPic-treated groups in the porcine model. Copyright © 2011 Elsevier GmbH. All rights reserved.

Modeling Drosophila Positional Preferences in Open Field Arenas with Directional Persistence and Wall Attraction

PubMed Central

Soibam, Benjamin; Goldfeder, Rachel L.; Manson-Bishop, Claire; Gamblin, Rachel; Pletcher, Scott D.; Shah, Shishir; Gunaratne, Gemunu H.; Roman, Gregg W.

2012-01-01

In open field arenas, Drosophila adults exhibit a preference for arena boundaries over internal walls and open regions. Herein, we investigate the nature of this preference using phenomenological modeling of locomotion to determine whether local arena features and constraints on movement alone are sufficient to drive positional preferences within open field arenas of different shapes and with different internal features. Our model has two components: directional persistence and local wall force. In regions far away from walls, the trajectory is entirely characterized by a directional persistence probability, , for each movement defined by the step size, , and the turn angle, . In close proximity to walls, motion is computed from and a local attractive force which depends on the distance between the fly and points on the walls. The directional persistence probability was obtained experimentally from trajectories of wild type Drosophila in a circular open field arena and the wall force was computed to minimize the difference between the radial distributions from the model and Drosophila in the same circular arena. The two-component model for fly movement was challenged by comparing the positional preferences from the two-component model to wild type Drosophila in a variety of open field arenas. In most arenas there was a strong concordance between the two-component model and Drosophila. In more complex arenas, the model exhibits similar trends, but some significant differences were found. These differences suggest that there are emergent features within these complex arenas that have significance for the fly, such as potential shelter. Hence, the two-component model is an important step in defining how Drosophila interact with their environment. PMID:23071591

Comparing observed and predicted mortality among ICUs using different prognostic systems: why do performance assessments differ?

PubMed

Kramer, Andrew A; Higgins, Thomas L; Zimmerman, Jack E

2015-02-01

To compare ICU performance using standardized mortality ratios generated by the Acute Physiology and Chronic Health Evaluation IVa and a National Quality Forum-endorsed methodology and examine potential reasons for model-based standardized mortality ratio differences. Retrospective analysis of day 1 hospital mortality predictions at the ICU level using Acute Physiology and Chronic Health Evaluation IVa and National Quality Forum models on the same patient cohort. Forty-seven ICUs at 36 U.S. hospitals from January 2008 to May 2013. Eighty-nine thousand three hundred fifty-three consecutive unselected ICU admissions. None. We assessed standardized mortality ratios for each ICU using data for patients eligible for Acute Physiology and Chronic Health Evaluation IVa and National Quality Forum predictions in order to compare unit-level model performance, differences in ICU rankings, and how case-mix adjustment might explain standardized mortality ratio differences. Hospital mortality was 11.5%. Overall standardized mortality ratio was 0.89 using Acute Physiology and Chronic Health Evaluation IVa and 1.07 using National Quality Forum, the latter having a widely dispersed and multimodal standardized mortality ratio distribution. Model exclusion criteria eliminated mortality predictions for 10.6% of patients for Acute Physiology and Chronic Health Evaluation IVa and 27.9% for National Quality Forum. The two models agreed on the significance and direction of standardized mortality ratio only 45% of the time. Four ICUs had standardized mortality ratios significantly less than 1.0 using Acute Physiology and Chronic Health Evaluation IVa, but significantly greater than 1.0 using National Quality Forum. Two ICUs had standardized mortality ratios exceeding 1.75 using National Quality Forum, but nonsignificant performance using Acute Physiology and Chronic Health Evaluation IVa. Stratification by patient and institutional characteristics indicated that units caring for more severely ill patients and those with a higher percentage of patients on mechanical ventilation had the most discordant standardized mortality ratios between the two predictive models. Acute Physiology and Chronic Health Evaluation IVa and National Quality Forum models yield different ICU performance assessments due to differences in case-mix adjustment. Given the growing role of outcomes in driving prospective payment patient referral and public reporting, performance should be assessed by models with fewer exclusions, superior accuracy, and better case-mix adjustment.

Multiobjective optimization model of intersection signal timing considering emissions based on field data: A case study of Beijing.

PubMed

Kou, Weibin; Chen, Xumei; Yu, Lei; Gong, Huibo

2018-04-18

Most existing signal timing models are aimed to minimize the total delay and stops at intersections, without considering environmental factors. This paper analyzes the trade-off between vehicle emissions and traffic efficiencies on the basis of field data. First, considering the different operating modes of cruising, acceleration, deceleration, and idling, field data of emissions and Global Positioning System (GPS) are collected to estimate emission rates for heavy-duty and light-duty vehicles. Second, multiobjective signal timing optimization model is established based on a genetic algorithm to minimize delay, stops, and emissions. Finally, a case study is conducted in Beijing. Nine scenarios are designed considering different weights of emission and traffic efficiency. The results compared with those using Highway Capacity Manual (HCM) 2010 show that signal timing optimized by the model proposed in this paper can decrease vehicles delay and emissions more significantly. The optimization model can be applied in different cities, which provides supports for eco-signal design and development. Vehicle emissions are heavily at signal intersections in urban area. The multiobjective signal timing optimization model is proposed considering the trade-off between vehicle emissions and traffic efficiencies on the basis of field data. The results indicate that signal timing optimized by the model proposed in this paper can decrease vehicle emissions and delays more significantly. The optimization model can be applied in different cities, which provides supports for eco-signal design and development.

The Impact of Role Models on Health Outcomes for Lesbian, Gay, Bisexual and Transgender Youth

PubMed Central

Bird, Jason D. P.; Kuhns, Lisa; Garofalo, Robert

2011-01-01

Purpose There is little research on the impact of role models on health outcomes for Lesbian, Gay, Bisexual, and Transgender (LGBT) youth. This exploratory study describes the presence and availability of LGBT affirming role models and examines the relationship between the accessibility of role models and health outcomes among a community-based sample of LGBT youth. Methods A convenience sample of 496 ethnically-diverse, 16–24 year old LGBT youth was recruited to complete a computer-assisted interview using standardized instruments validated with adolescents. The prevalence and characteristics of role models was described. Differences in subgroup distribution were assessed using Pearson Chi-square (p<0.05). Differences in health outcomes for those with and without role models and the nature of those role models were determined using analysis of co-variance (ANCOVA) models, with post hoc Bonferroni tests to probe significant global findings. Results Sixty-percent of the participants reported having a role model, with younger participants significantly more likely to report having a role model. A majority of the participants reported having inaccessible role models, especially among younger participants. The presence and accessibility of a role model did not have a significant relationship to binge drinking, drug use, or STI diagnoses; however, participants with inaccessible role models showed increased psychological distress versus those with accessible or no role models. Conclusions Inaccessible role models may not be sufficient for protecting youth from negative outcomes and formal mechanisms for connecting LGBT youth with caring adults who can serve as role models, such as mentoring programs, are critical. PMID:22443838

Evaluating the capabilities of watershed-scale models in estimating sediment yield at field-scale.

PubMed

Sommerlot, Andrew R; Nejadhashemi, A Pouyan; Woznicki, Sean A; Giri, Subhasis; Prohaska, Michael D

2013-09-30

Many watershed model interfaces have been developed in recent years for predicting field-scale sediment loads. They share the goal of providing data for decisions aimed at improving watershed health and the effectiveness of water quality conservation efforts. The objectives of this study were to: 1) compare three watershed-scale models (Soil and Water Assessment Tool (SWAT), Field_SWAT, and the High Impact Targeting (HIT) model) against calibrated field-scale model (RUSLE2) in estimating sediment yield from 41 randomly selected agricultural fields within the River Raisin watershed; 2) evaluate the statistical significance among models; 3) assess the watershed models' capabilities in identifying areas of concern at the field level; 4) evaluate the reliability of the watershed-scale models for field-scale analysis. The SWAT model produced the most similar estimates to RUSLE2 by providing the closest median and the lowest absolute error in sediment yield predictions, while the HIT model estimates were the worst. Concerning statistically significant differences between models, SWAT was the only model found to be not significantly different from the calibrated RUSLE2 at α = 0.05. Meanwhile, all models were incapable of identifying priorities areas similar to the RUSLE2 model. Overall, SWAT provided the most correct estimates (51%) within the uncertainty bounds of RUSLE2 and is the most reliable among the studied models, while HIT is the least reliable. The results of this study suggest caution should be exercised when using watershed-scale models for field level decision-making, while field specific data is of paramount importance. Copyright © 2013 Elsevier Ltd. All rights reserved.

A Comparison of Two Balance Calibration Model Building Methods

NASA Technical Reports Server (NTRS)

DeLoach, Richard; Ulbrich, Norbert

2007-01-01

Simulated strain-gage balance calibration data is used to compare the accuracy of two balance calibration model building methods for different noise environments and calibration experiment designs. The first building method obtains a math model for the analysis of balance calibration data after applying a candidate math model search algorithm to the calibration data set. The second building method uses stepwise regression analysis in order to construct a model for the analysis. Four balance calibration data sets were simulated in order to compare the accuracy of the two math model building methods. The simulated data sets were prepared using the traditional One Factor At a Time (OFAT) technique and the Modern Design of Experiments (MDOE) approach. Random and systematic errors were introduced in the simulated calibration data sets in order to study their influence on the math model building methods. Residuals of the fitted calibration responses and other statistical metrics were compared in order to evaluate the calibration models developed with different combinations of noise environment, experiment design, and model building method. Overall, predicted math models and residuals of both math model building methods show very good agreement. Significant differences in model quality were attributable to noise environment, experiment design, and their interaction. Generally, the addition of systematic error significantly degraded the quality of calibration models developed from OFAT data by either method, but MDOE experiment designs were more robust with respect to the introduction of a systematic component of the unexplained variance.

What is the role of historical anthropogenically-induced land-cover change on the surface climate of West Africa? Results from the LUCID intercomparison project

NASA Astrophysics Data System (ADS)

Souleymane, S.

2015-12-01

West Africa has been highlighted as a hot spot of land surface-atmosphere interactions. This study analyses the outputs of the project Land-Use and Climate, IDentification of Robust Impacts (LUCID) over West Africa. LUCID used seven atmosphere-land models with a common experimental design to explore the impacts of Land Use induced Land Cover Change (LULCC) that are robust and consistent across the climate models. Focusing the analysis on Sahel and Guinea, this study shows that, even though the seven climate models use the same atmospheric and land cover forcing, there are significant differences of West African Monsoon variability across the climate models. The magnitude of that variability differs significantly from model to model resulting two major "features": (1) atmosphere dynamics models; (2) how the land-surface functioning is parameterized in the Land surface Model, in particular regarding the evapotranspiration partitioning within the different land-cover types, as well as the role of leaf area index (LAI) in the flux calculations and how strongly the surface is coupled to the atmosphere. The major role that the models'sensitivity to land-cover perturbations plays in the resulting climate impacts of LULCC has been analysed in this study. The climate models show, however, significant differences in the magnitude and the seasonal partitioning of the temperature change. The LULCC induced cooling is directed by decreases in net shortwave radiation that reduced the available energy (QA) (related to changes in land-cover properties other than albedo, such as LAI and surface roughness), which decreases during most part of the year. The biophysical impacts of LULCC were compared to the impact of elevated greenhouse gases resulting changes in sea surface temperatures and sea ice extent (CO2SST). The results show that the surface cooling (related a decrease in QA) induced by the biophysical effects of LULCC are insignificant compared to surface warming (related an increase in QA), which is induced by the regional significance effect of CO2SST due to a small LULCC imposed. In contrast, the decrease of surface water balance resulting from LULCC effect is a similar sign to those resulting from CO2SST but the signal resulting of the biophysical effects of LULCC is stronger than the regional CO2SST impact.

Choices and changes: Eccles' Expectancy-Value model and upper-secondary school students' longitudinal reflections about their choice of a STEM education

NASA Astrophysics Data System (ADS)

Lykkegaard, Eva; Ulriksen, Lars

2016-03-01

During the past 30 years, Eccles' comprehensive social-psychological Expectancy-Value Model of Motivated Behavioural Choices (EV-MBC model) has been proven suitable for studying educational choices related to Science, Technology, Engineering and/or Mathematics (STEM). The reflections of 15 students in their last year in upper-secondary school concerning their choice of tertiary education were examined using quantitative EV-MBC surveys and repeated qualitative interviews. This article presents the analyses of three cases in detail. The analytical focus was whether the factors indicated in the EV-MBC model could be used to detect significant changes in the students' educational choice processes. An important finding was that the quantitative EV-MBC surveys and the qualitative interviews gave quite different results concerning the students' considerations about the choice of tertiary education, and that significant changes in the students' reflections were not captured by the factors of the EV-MBC model. This questions the validity of the EV-MBC surveys. Moreover, the quantitative factors from the EV-MBC model did not sufficiently explain students' dynamical educational choice processes where students in parallel considered several different potential educational trajectories. We therefore call for further studies of the EV-MBC model's use in describing longitudinal choice processes and especially in investigating significant changes.

Regional Retinal Ganglion Cell Axon Loss in a Murine Glaucoma Model

PubMed Central

Schaub, Julie A.; Kimball, Elizabeth C.; Steinhart, Matthew R.; Nguyen, Cathy; Pease, Mary E.; Oglesby, Ericka N.; Jefferys, Joan L.; Quigley, Harry A.

2017-01-01

Purpose To determine if retinal ganglion cell (RGC) axon loss in experimental mouse glaucoma is uniform in the optic nerve. Methods Experimental glaucoma was induced for 6 weeks with a microbead injection model in CD1 (n = 78) and C57BL/6 (B6, n = 68) mice. From epoxy-embedded sections of optic nerve 1 to 2 mm posterior to the globe, total nerve area and regional axon density (axons/1600 μm2) were measured in superior, inferior, nasal, and temporal zones. Results Control eyes of CD1 mice have higher axon density and more total RGCs than control B6 mice eyes. There were no significant differences in control regional axon density in all mice or by strain (all P > 0.2, mixed model). Exposure to elevated IOP caused loss of RGC in both strains. In CD1 mice, axon density declined without significant loss of nerve area, while B6 mice had less density loss, but greater decrease in nerve area. Axon density loss in glaucoma eyes was not significantly greater in any region in either mouse strain (both P > 0.2, mixed model). In moderately damaged CD1 glaucoma eyes, and CD1 eyes with the greatest IOP elevation exposure, density loss differed by region (P = 0.05, P = 0.03, mixed model) with the greatest loss in the temporal and superior regions, while in severely injured B6 nerves superior loss was greater than inferior loss (P = 0.01, mixed model, Bonferroni corrected). Conclusions There was selectively greater loss of superior and temporal optic nerve axons of RGCs in mouse glaucoma at certain stages of damage. Differences in nerve area change suggest non-RGC responses differ between mouse strains. PMID:28549091

Marginal and internal fit of cobalt-chromium copings fabricated using the conventional and the direct metal laser sintering techniques: A comparative in vitro study.

PubMed

Ullattuthodi, Sujana; Cherian, Kandathil Phillip; Anandkumar, R; Nambiar, M Sreedevi

2017-01-01

This in vitro study seeks to evaluate and compare the marginal and internal fit of cobalt-chromium copings fabricated using the conventional and direct metal laser sintering (DMLS) techniques. A master model of a prepared molar tooth was made using cobalt-chromium alloy. Silicone impression of the master model was made and thirty standardized working models were then produced; twenty working models for conventional lost-wax technique and ten working models for DMLS technique. A total of twenty metal copings were fabricated using two different production techniques: conventional lost-wax method and DMLS; ten samples in each group. The conventional and DMLS copings were cemented to the working models using glass ionomer cement. Marginal gap of the copings were measured at predetermined four points. The die with the cemented copings are standardized-sectioned with a heavy duty lathe. Then, each sectioned samples were analyzed for the internal gap between the die and the metal coping using a metallurgical microscope. Digital photographs were taken at ×50 magnification and analyzed using measurement software. Statistical analysis was done by unpaired t -test and analysis of variance (ANOVA). The results of this study reveal that no significant difference was present in the marginal gap of conventional and DMLS copings ( P > 0.05) by means of ANOVA. The mean values of internal gap of DMLS copings were significantly greater than that of conventional copings ( P < 0.05). Within the limitations of this in vitro study, it was concluded that the internal fit of conventional copings was superior to that of the DMLS copings. Marginal fit of the copings fabricated by two different techniques had no significant difference.

Determinants of birth intervals in Kerala: an application of Cox's hazard model.

PubMed

Nair, S N

1996-01-01

"The present study is an attempt to delineate the differences in the patterns and determinants of birth intervals which appear highly relevant in a transitional population such as Kerala [India]. In this country two comparable surveys, with a period difference of 20 years, were conducted. The study tries to estimate the effects of socio-economic, demographic and proximate variables using Cox's proportional hazard model. For the former data-set, socio-economic variables have [a] significant effect on birth intervals, while for the latter data proximate variables are the significant determinants of birth intervals." (SUMMARY IN ITA AND FRE) excerpt

Global stability of a two-mediums rumor spreading model with media coverage

NASA Astrophysics Data System (ADS)

Huo, Liang'an; Wang, Li; Song, Guoxiang

2017-09-01

Rumor spreading is a typical form of social communication and plays a significant role in social life, and media coverage has a great influence on the spread of rumor. In this paper, we present a new model with two media coverage to investigate the impact of the different mediums on rumor spreading. Then, we calculate the equilibria of the model and construct the reproduction number ℜ0. And we prove the global asymptotic stability of equilibria by using Lyapunov functions. Finally, we can conclude that the transition rate of the ignorants between two mediums has a direct effect on the scale of spreaders, and different media coverage has significant effects on the dynamics behaviors of rumor spreading.

Firefly algorithm versus genetic algorithm as powerful variable selection tools and their effect on different multivariate calibration models in spectroscopy: A comparative study

NASA Astrophysics Data System (ADS)

Attia, Khalid A. M.; Nassar, Mohammed W. I.; El-Zeiny, Mohamed B.; Serag, Ahmed

2017-01-01

For the first time, a new variable selection method based on swarm intelligence namely firefly algorithm is coupled with three different multivariate calibration models namely, concentration residual augmented classical least squares, artificial neural network and support vector regression in UV spectral data. A comparative study between the firefly algorithm and the well-known genetic algorithm was developed. The discussion revealed the superiority of using this new powerful algorithm over the well-known genetic algorithm. Moreover, different statistical tests were performed and no significant differences were found between all the models regarding their predictabilities. This ensures that simpler and faster models were obtained without any deterioration of the quality of the calibration.

Effects of physical education, extracurricular sports activities, and leisure satisfaction on adolescent aggressive behavior: A latent growth modeling approach.

PubMed

Park, Sanghyun; Chiu, Weisheng; Won, Doyeon

2017-01-01

The present study aimed to investigate the longitudinal influence of physical education classes, extracurricular sports activities, and leisure satisfaction on aggressive behavior among South Korean adolescents. Data were drawn from the Korea Youth Panel Survey. We used latent growth curve modeling to explain the growth trajectory of adolescent aggressive behaviors and a multi-group analysis to investigate gender differences in aggressive behavior. The results indicated that adolescents' aggressive behavior significantly changed with age. There were significant gender-based differences in the level of and changes in aggressive behavior over time. Both extracurricular sports activities and leisure satisfaction had significant influences on the changes in adolescents' aggressive behavior with age, whereas physical education classes did not.

A general model for estimating lower extremity inertial properties of individuals with transtibial amputation.

PubMed

Ferris, Abbie E; Smith, Jeremy D; Heise, Gary D; Hinrichs, Richard N; Martin, Philip E

2017-03-21

Lower extremity joint moment magnitudes during swing are dependent on the inertial properties of the prosthesis and residual limb of individuals with transtibial amputation (TTA). Often, intact limb inertial properties (INTACT) are used for prosthetic limb values in an inverse dynamics model even though these values overestimate the amputated limb's inertial properties. The purpose of this study was to use subject-specific (SPECIFIC) measures of prosthesis inertial properties to generate a general model (GENERAL) for estimating TTA prosthesis inertial properties. Subject-specific mass, center of mass, and moment of inertia were determined for the shank and foot segments of the prosthesis (n=11) using an oscillation technique and reaction board. The GENERAL model was derived from the means of the SPECIFIC model. Mass and segment lengths are required GENERAL model inputs. Comparisons of segment inertial properties and joint moments during walking were made using three inertial models (unique sample; n=9): (1) SPECIFIC, (2) GENERAL, and (3) INTACT. Prosthetic shank inertial properties were significantly smaller with the SPECIFIC and GENERAL model than the INTACT model, but the SPECIFIC and GENERAL model did not statistically differ. Peak knee and hip joint moments during swing were significantly smaller for the SPECIFIC and GENERAL model compared with the INTACT model and were not significantly different between SPECIFIC and GENERAL models. When subject-specific measures are unavailable, using the GENERAL model produces a better estimate of prosthetic side inertial properties resulting in more accurate joint moment measurements for individuals with TTA than the INTACT model. Copyright © 2017 Elsevier Ltd. All rights reserved.

Shortwave forcing and feedbacks in Last Glacial Maximum and Mid-Holocene PMIP3 simulations.

PubMed

Braconnot, Pascale; Kageyama, Masa

2015-11-13

Simulations of the climates of the Last Glacial Maximum (LGM), 21 000 years ago, and of the Mid-Holocene (MH), 6000 years ago, allow an analysis of climate feedbacks in climate states that are radically different from today. The analyses of cloud and surface albedo feedbacks show that the shortwave cloud feedback is a major driver of differences between model results. Similar behaviours appear when comparing the LGM and MH simulated changes, highlighting the fingerprint of model physics. Even though the different feedbacks show similarities between the different climate periods, the fact that their relative strength differs from one climate to the other prevents a direct comparison of past and future climate sensitivity. The land-surface feedback also shows large disparities among models even though they all produce positive sea-ice and snow feedbacks. Models have very different sensitivities when considering the vegetation feedback. This feedback has a regional pattern that differs significantly between models and depends on their level of complexity and model biases. Analyses of the MH climate in two versions of the IPSL model provide further indication on the possibilities to assess the role of model biases and model physics on simulated climate changes using past climates for which observations can be used to assess the model results. © 2015 The Author(s).

Inverse modeling of hydrologic parameters using surface flux and runoff observations in the Community Land Model

NASA Astrophysics Data System (ADS)

Sun, Y.; Hou, Z.; Huang, M.; Tian, F.; Leung, L. Ruby

2013-12-01

This study demonstrates the possibility of inverting hydrologic parameters using surface flux and runoff observations in version 4 of the Community Land Model (CLM4). Previous studies showed that surface flux and runoff calculations are sensitive to major hydrologic parameters in CLM4 over different watersheds, and illustrated the necessity and possibility of parameter calibration. Both deterministic least-square fitting and stochastic Markov-chain Monte Carlo (MCMC)-Bayesian inversion approaches are evaluated by applying them to CLM4 at selected sites with different climate and soil conditions. The unknowns to be estimated include surface and subsurface runoff generation parameters and vadose zone soil water parameters. We find that using model parameters calibrated by the sampling-based stochastic inversion approaches provides significant improvements in the model simulations compared to using default CLM4 parameter values, and that as more information comes in, the predictive intervals (ranges of posterior distributions) of the calibrated parameters become narrower. In general, parameters that are identified to be significant through sensitivity analyses and statistical tests are better calibrated than those with weak or nonlinear impacts on flux or runoff observations. Temporal resolution of observations has larger impacts on the results of inverse modeling using heat flux data than runoff data. Soil and vegetation cover have important impacts on parameter sensitivities, leading to different patterns of posterior distributions of parameters at different sites. Overall, the MCMC-Bayesian inversion approach effectively and reliably improves the simulation of CLM under different climates and environmental conditions. Bayesian model averaging of the posterior estimates with different reference acceptance probabilities can smooth the posterior distribution and provide more reliable parameter estimates, but at the expense of wider uncertainty bounds.

[The aspiratory resistance and filtration penetration of N95 filtering-facepiece respirators used widely in China].

PubMed

Wang, Xinyan; Shi, Tingming; Lu, Wei; Qin, Shaoxian; Liu, Yuewei; Tao, Ying; Zhang, Hongge; Chen, Weihong

2015-01-01

The objective of this study was to investigate the aspiratory resistance, filtration penetration and their influence factors of N95 filtering-facepiece respirators used widely in China. The total of 6 brands and 21 models of N95 filtering-facepiece respirators which are certified and big sales on the market. The aspiratory resistance and filtration efficiency filter penetration were measured while air pump ran from 10 L/min to 100 L/min using differential pressure gauge and the PortaCount, respectively. The filtration penetrations for 2 of the 21 models were lower than 95%, and the qualified rate for all models was 90.47%. The filtration penetrations gradually decreased when ventilation flow of air pump increased. The negative correlation was observed between filtration penetration and ventilation flow (r(2) = 0.711, P < 0.05). The resistances of all 21 models of N95 respirators met the requirements of the national standard. The aspiratory resistance started to elevate with the increasing of ventilation flow, and a positive correlation between both (r(2) = 0.878, P < 0.05). Significant differences of filtration penetration and aspiratory resistance were observed among between different brands (P < 0.05) although no differences of filtration penetration existed among different models of one brand (P > 0.05). But the differences of the aspiratory resistance among different models of one brand were statistically significant (P < 0.05). The aspiratory resistances of all N95 filtering-facepiece respirators used in this study met the requirements of the national standard. And the qualified ratio of filtration penetration of all models was higher than 90%. The influencing factors of aspiratory resistance included materials, size and ventilation flow. And influencing factors for filtration penetration were materials and ventilation flow.

The Effect of Orem’s Self-Care Model on Fatigue in Patients With Multiple Sclerosis: A Single Blind Randomized Clinical Trial Study

PubMed Central

Afrasiabifar, Ardashir; Mehri, Zahra; Javad Sadat, Saied; Ghaffarian Shirazi, Hamid Reza

2016-01-01

Background Orem’s self-care model is a nursing model that was introduced with the purpose of improving the self-care of individuals, especially patients suffering from chronic diseases. Objectives To determining the effect of Orem’s self-care model on fatigue in multiple sclerosis patients. Patients and Methods This research involved a clinical trial. Sixty-three multiple sclerosis patients at the vice-chancellor in treatment affairs of Yasuj University of Medical Sciences were selected based on nonrandom sampling, but they were allocated to the two groups based on random allocation. In the intervention group, Orem’s model was applied during six sessions of 45 - 60 minutes in length, and the process continued for 1 month. The data were collected 1 week before and 7 weeks after the end of the intervention using the Orem’s self-care model-based assessment form and fatigue severity scale, the validity and reliability of which have been Results Before the intervention, 11.11% of the participants had a good knowledge of self-care. In addition, self-care willingness and skills were observed in 76.19% and 4.76% of participants, respectively. The mean difference in fatigue reduced significantly in the intervention group after the intervention (P < 0.05). After the intervention, a statistically significant difference was observed in the mean difference of fatigue between the two groups (P < 0.05). Conclusions Orem’s self-care model is significantly effective in reducing the fatigue of multiple sclerosis patients. PMID:27781119

Modelling the water energy nexus: should variability in water supply impact on decision making for future energy supply options?

NASA Astrophysics Data System (ADS)

Cullis, James D. S.; Walker, Nicholas J.; Ahjum, Fadiel; Juan Rodriguez, Diego

2018-02-01

Many countries, like South Africa, Australia, India, China and the United States, are highly dependent on coal fired power stations for energy generation. These power stations require significant amounts of water, particularly when fitted with technology to reduce pollution and climate change impacts. As water resources come under stress it is important that spatial variability in water availability is taken into consideration for future energy planning particularly with regards to motivating for a switch from coal fired power stations to renewable technologies. This is particularly true in developing countries where there is a need for increased power production and associated increasing water demands for energy. Typically future energy supply options are modelled using a least cost optimization model such as TIMES that considers water supply as an input cost, but is generally constant for all technologies. Different energy technologies are located in different regions of the country with different levels of water availability and associated infrastructure development and supply costs. In this study we develop marginal cost curves for future water supply options in different regions of a country where different energy technologies are planned for development. These water supply cost curves are then used in an expanded version of the South Africa TIMES model called SATIM-W that explicitly models the water-energy nexus by taking into account the regional nature of water supply availability associated with different energy supply technologies. The results show a significant difference in the optimal future energy mix and in particular an increase in renewables and a demand for dry-cooling technologies that would not have been the case if the regional variability of water availability had not been taken into account. Choices in energy policy, such as the introduction of a carbon tax, will also significantly impact on future water resources, placing additional water demands in some regions and making water available for other users in other regions with a declining future energy demand. This study presents a methodology for modelling the water-energy nexus that could be used to inform the sustainable development planning process in the water and energy sectors for both developed and developing countries.

Pronation-Supination Motion Is Altered in a Rat Model of Post-Traumatic Elbow Contracture.

PubMed

Dunham, Chelsey L; Castile, Ryan M; Chamberlain, Aaron M; Galatz, Leesa M; Lake, Spencer P

2017-07-01

The elbow joint is highly susceptible to joint contracture, and treating elbow contracture is a challenging clinical problem. Previously, we established an animal model to study elbow contracture that exhibited features similar to the human condition including persistent decreased range of motion (ROM) in flexion-extension and increased capsule thickness/adhesions. The objective of this study was to mechanically quantify pronation-supination in different injury models to determine if significant differences compared to control or contralateral persist long-term in our animal elbow contracture model. After surgically inducing soft tissue damage in the elbow, Injury I (anterior capsulotomy) and Injury II (anterior capsulotomy with lateral collateral ligament transection), limbs were immobilized for 6 weeks (immobilization (IM)). Animals were evaluated after the IM period or following an additional 6 weeks of free mobilization (FM). Total ROM for pronation-supination was significantly decreased compared to the uninjured contralateral limb for both IM and FM, although not different from control limbs. Specifically, for both IM and FM, total ROM for Injury I and Injury II was significantly decreased by ∼20% compared to contralateral. Correlations of measurements from flexion-extension and pronation-supination divulged that FM did not affect these motions in the same way, demonstrating that joint motions need to be studied/treated separately. Overall, injured limbs exhibited persistent motion loss in pronation-supination when comparing side-to-side differences, similar to human post-traumatic joint contracture. Future work will use this animal model to study how elbow periarticular soft tissues contribute to contracture.

Explaining the black-white gap in cognitive test scores: Toward a theory of adverse impact.

PubMed

Cottrell, Jonathan M; Newman, Daniel A; Roisman, Glenn I

2015-11-01

In understanding the causes of adverse impact, a key parameter is the Black-White difference in cognitive test scores. To advance theory on why Black-White cognitive ability/knowledge test score gaps exist, and on how these gaps develop over time, the current article proposes an inductive explanatory model derived from past empirical findings. According to this theoretical model, Black-White group mean differences in cognitive test scores arise from the following racially disparate conditions: family income, maternal education, maternal verbal ability/knowledge, learning materials in the home, parenting factors (maternal sensitivity, maternal warmth and acceptance, and safe physical environment), child birth order, and child birth weight. Results from a 5-wave longitudinal growth model estimated on children in the NICHD Study of Early Child Care and Youth Development from ages 4 through 15 years show significant Black-White cognitive test score gaps throughout early development that did not grow significantly over time (i.e., significant intercept differences, but not slope differences). Importantly, the racially disparate conditions listed above can account for the relation between race and cognitive test scores. We propose a parsimonious 3-Step Model that explains how cognitive test score gaps arise, in which race relates to maternal disadvantage, which in turn relates to parenting factors, which in turn relate to cognitive test scores. This model and results offer to fill a need for theory on the etiology of the Black-White ethnic group gap in cognitive test scores, and attempt to address a missing link in the theory of adverse impact. (c) 2015 APA, all rights reserved).

Dynamic train-track interaction at high vehicle speeds—Modelling of wheelset dynamics and wheel rotation

NASA Astrophysics Data System (ADS)

Torstensson, P. T.; Nielsen, J. C. O.; Baeza, L.

2011-10-01

Vertical dynamic train-track interaction at high vehicle speeds is investigated in a frequency range from about 20 Hz to 2.5 kHz. The inertial effects due to wheel rotation are accounted for in the vehicle model by implementing a structural dynamics model of a rotating wheelset. Calculated wheel-rail contact forces using the flexible, rotating wheelset model are compared with contact forces based on rigid, non-rotating models. For a validation of the train-track interaction model, calculated contact forces are compared with contact forces measured using an instrumented wheelset. When the system is excited at a frequency where two different wheelset mode shapes, due to the wheel rotation, have coinciding resonance frequencies, significant differences are found in the contact forces calculated with the rotating and non-rotating wheelset models. Further, the use of a flexible, rotating wheelset model is recommended for load cases leading to large magnitude contact force components in the high-frequency range (above 1.5 kHz). In particular, the influence of the radial wheel eigenmodes with two or three nodal diameters is significant.

Fine tuning breath-hold-based cerebrovascular reactivity analysis models.

PubMed

van Niftrik, Christiaan Hendrik Bas; Piccirelli, Marco; Bozinov, Oliver; Pangalu, Athina; Valavanis, Antonios; Regli, Luca; Fierstra, Jorn

2016-02-01

We elaborate on existing analysis methods for breath-hold (BH)-derived cerebrovascular reactivity (CVR) measurements and describe novel insights and models toward more exact CVR interpretation. Five blood-oxygen-level-dependent (BOLD) fMRI datasets of neurovascular patients with unilateral hemispheric hemodynamic impairment were used to test various BH CVR analysis methods. Temporal lag (phase), percent BOLD signal change (CVR), and explained variance (coherence) maps were calculated using three different sine models and two novel "Optimal Signal" model-free methods based on the unaffected hemisphere and the sagittal sinus fMRI signal time series, respectively. All models showed significant differences in CVR and coherence between the affected-hemodynamic impaired-and unaffected hemisphere. Voxel-wise phase determination significantly increases CVR (0.60 ± 0.18 vs. 0.82 ± 0.27; P < 0.05). Incorporating different durations of breath hold and resting period in one sine model (two-task) did increase coherence in the unaffected hemisphere, as well as eliminating negative phase commonly obtained by one-task frequency models. The novel model-free "optimal signal" methods both explained the BOLD MR data similar to the two task sine model. Our CVR analysis demonstrates an improved CVR and coherence after implementation of voxel-wise phase and frequency adjustment. The novel "optimal signal" methods provide a robust and feasible alternative to the sine models, as both are model-free and independent of compliance. Here, the sagittal sinus model may be advantageous, as it is independent of hemispheric CVR impairment.

Reproducibility of Brain Morphometry from Short-Term Repeat Clinical MRI Examinations: A Retrospective Study

PubMed Central

Liu, Hon-Man; Chen, Shan-Kai; Chen, Ya-Fang; Lee, Chung-Wei; Yeh, Lee-Ren

2016-01-01

Purpose To assess the inter session reproducibility of automatic segmented MRI-derived measures by FreeSurfer in a group of subjects with normal-appearing MR images. Materials and Methods After retrospectively reviewing a brain MRI database from our institute consisting of 14,758 adults, those subjects who had repeat scans and had no history of neurodegenerative disorders were selected for morphometry analysis using FreeSurfer. A total of 34 subjects were grouped by MRI scanner model. After automatic segmentation using FreeSurfer, label-wise comparison (involving area, thickness, and volume) was performed on all segmented results. An intraclass correlation coefficient was used to estimate the agreement between sessions. Wilcoxon signed rank test was used to assess the population mean rank differences across sessions. Mean-difference analysis was used to evaluate the difference intervals across scanners. Absolute percent difference was used to estimate the reproducibility errors across the MRI models. Kruskal-Wallis test was used to determine the across-scanner effect. Results The agreement in segmentation results for area, volume, and thickness measurements of all segmented anatomical labels was generally higher in Signa Excite and Verio models when compared with Sonata and TrioTim models. There were significant rank differences found across sessions in some labels of different measures. Smaller difference intervals in global volume measurements were noted on images acquired by Signa Excite and Verio models. For some brain regions, significant MRI model effects were observed on certain segmentation results. Conclusions Short-term scan-rescan reliability of automatic brain MRI morphometry is feasible in the clinical setting. However, since repeatability of software performance is contingent on the reproducibility of the scanner performance, the scanner performance must be calibrated before conducting such studies or before using such software for retrospective reviewing. PMID:26812647

Technical strategy of triple jump: differences of inverted pendulum model between hop-dominated and balance techniques.

PubMed

Fujibayashi, Nobuaki; Otsuka, Mitsuo; Yoshioka, Shinsuke; Isaka, Tadao

2017-10-24

The present study aims to cross-sectionally clarify the characteristics of the motions of an inverted pendulum model, a stance leg, a swing leg and arms in different triple-jumping techniques to understand whether or not hop displacement is relatively longer rather than step and jump displacements. Eighteen male athletes performed the triple jump with a full run-up. Based on the technique of the jumpers, they were classified as hop-dominated (n = 10) or balance (n = 8) jumpers. The kinematic data were calculated using motion capture and compared between the two techniques using the inverted pendulum model. The hop-dominated jumpers had a significantly longer hop displacement and faster vertical centre-of-mass (COM) velocity of their whole body at hop take-off, which was generated by faster rotation behaviours of inverted pendulum model and faster swinging behaviours of arms. Conversely, balance jumpers had a significantly longer jump displacement and faster horizontal COM velocity of their whole body at take-off, which was generated by a stiffer inverted pendulum model and stance leg. The results demonstrate that hop-dominated and balance jumpers enhanced each dominated-jump displacement using different swing- and stance-leg motions. This information may help to enhance the actual displacement of triple jumpers using different jumping techniques.

The Stability of Social Desirability: A Latent Change Analysis.

PubMed

Haberecht, Katja; Schnuerer, Inga; Gaertner, Beate; John, Ulrich; Freyer-Adam, Jennis

2015-08-01

Social desirability has been shown to be stable in samples with higher school education. However, little is known about the stability of social desirability in more heterogeneous samples differing in school education. This study aimed to investigate the stability of social desirability and which factors predict interindividual differences in intraindividual change. As part of a randomized controlled trial, 1,243 job seekers with unhealthy alcohol use were systematically recruited at three job agencies. A total of 1,094 individuals (87.8%) participated in at least one of two follow-ups (6 and 15 months after baseline) and constitute this study's sample. The Social Desirability Scale-17 was applied. Two latent change models were conducted: Model 1 tested for interindividual differences in intraindividual change of social desirability between both follow-ups; Model 2 included possible predictors (age, sex, education, current employment status) of interindividual differences in intraindividual change. Model 1 revealed a significant decrease of social desirability over time. Model 2 revealed school education to be the only significant predictor of change. These findings indicate that stability of social desirability may depend on school education. It may not be as stable in individuals with higher school education as in individuals with lower education. © 2014 Wiley Periodicals, Inc.

Mapping black panthers: Macroecological modeling of melanism in leopards (Panthera pardus).

PubMed

da Silva, Lucas G; Kawanishi, Kae; Henschel, Philipp; Kittle, Andrew; Sanei, Arezoo; Reebin, Alexander; Miquelle, Dale; Stein, Andrew B; Watson, Anjali; Kekule, Laurence Bruce; Machado, Ricardo B; Eizirik, Eduardo

2017-01-01

The geographic distribution and habitat association of most mammalian polymorphic phenotypes are still poorly known, hampering assessments of their adaptive significance. Even in the case of the black panther, an iconic melanistic variant of the leopard (Panthera pardus), no map exists describing its distribution. We constructed a large database of verified records sampled across the species' range, and used it to map the geographic occurrence of melanism. We then estimated the potential distribution of melanistic and non-melanistic leopards using niche-modeling algorithms. The overall frequency of melanism was ca. 11%, with a significantly non-random spatial distribution. Distinct habitat types presented significantly different frequencies of melanism, which increased in Asian moist forests and approached zero across most open/dry biomes. Niche modeling indicated that the potential distributions of the two phenotypes were distinct, with significant differences in habitat suitability and rejection of niche equivalency between them. We conclude that melanism in leopards is strongly affected by natural selection, likely driven by efficacy of camouflage and/or thermoregulation in different habitats, along with an effect of moisture that goes beyond its influence on vegetation type. Our results support classical hypotheses of adaptive coloration in animals (e.g. Gloger's rule), and open up new avenues for in-depth evolutionary analyses of melanism in mammals.

Mapping black panthers: Macroecological modeling of melanism in leopards (Panthera pardus)

PubMed Central

da Silva, Lucas G.; Kawanishi, Kae; Henschel, Philipp; Kittle, Andrew; Sanei, Arezoo; Reebin, Alexander; Miquelle, Dale; Stein, Andrew B.; Watson, Anjali; Kekule, Laurence Bruce; Machado, Ricardo B.

2017-01-01

The geographic distribution and habitat association of most mammalian polymorphic phenotypes are still poorly known, hampering assessments of their adaptive significance. Even in the case of the black panther, an iconic melanistic variant of the leopard (Panthera pardus), no map exists describing its distribution. We constructed a large database of verified records sampled across the species’ range, and used it to map the geographic occurrence of melanism. We then estimated the potential distribution of melanistic and non-melanistic leopards using niche-modeling algorithms. The overall frequency of melanism was ca. 11%, with a significantly non-random spatial distribution. Distinct habitat types presented significantly different frequencies of melanism, which increased in Asian moist forests and approached zero across most open/dry biomes. Niche modeling indicated that the potential distributions of the two phenotypes were distinct, with significant differences in habitat suitability and rejection of niche equivalency between them. We conclude that melanism in leopards is strongly affected by natural selection, likely driven by efficacy of camouflage and/or thermoregulation in different habitats, along with an effect of moisture that goes beyond its influence on vegetation type. Our results support classical hypotheses of adaptive coloration in animals (e.g. Gloger’s rule), and open up new avenues for in-depth evolutionary analyses of melanism in mammals. PMID:28379961

Hierarchical model analysis of the Atlantic Flyway Breeding Waterfowl Survey

USGS Publications Warehouse

Sauer, John R.; Zimmerman, Guthrie S.; Klimstra, Jon D.; Link, William A.

2014-01-01

We used log-linear hierarchical models to analyze data from the Atlantic Flyway Breeding Waterfowl Survey. The survey has been conducted by state biologists each year since 1989 in the northeastern United States from Virginia north to New Hampshire and Vermont. Although yearly population estimates from the survey are used by the United States Fish and Wildlife Service for estimating regional waterfowl population status for mallards (Anas platyrhynchos), black ducks (Anas rubripes), wood ducks (Aix sponsa), and Canada geese (Branta canadensis), they are not routinely adjusted to control for time of day effects and other survey design issues. The hierarchical model analysis permits estimation of year effects and population change while accommodating the repeated sampling of plots and controlling for time of day effects in counting. We compared population estimates from the current stratified random sample analysis to population estimates from hierarchical models with alternative model structures that describe year to year changes as random year effects, a trend with random year effects, or year effects modeled as 1-year differences. Patterns of population change from the hierarchical model results generally were similar to the patterns described by stratified random sample estimates, but significant visibility differences occurred between twilight to midday counts in all species. Controlling for the effects of time of day resulted in larger population estimates for all species in the hierarchical model analysis relative to the stratified random sample analysis. The hierarchical models also provided a convenient means of estimating population trend as derived statistics from the analysis. We detected significant declines in mallard and American black ducks and significant increases in wood ducks and Canada geese, a trend that had not been significant for 3 of these 4 species in the prior analysis. We recommend using hierarchical models for analysis of the Atlantic Flyway Breeding Waterfowl Survey.

Cardiovascular cast model fabrication and casting effectiveness evaluation in fetus with severe congenital heart disease or normal heart.

PubMed

Wang, Yu; Cao, Hai-yan; Xie, Ming-xing; He, Lin; Han, Wei; Hong, Liu; Peng, Yuan; Hu, Yun-fei; Song, Ben-cai; Wang, Jing; Wang, Bin; Deng, Cheng

2016-04-01

To investigate the application and effectiveness of vascular corrosion technique in preparing fetal cardiovascular cast models, 10 normal fetal heart specimens with other congenital disease (control group) and 18 specimens with severe congenital heart disease (case group) from induced abortions were enrolled in this study from March 2013 to June 2015 in our hospital. Cast models were prepared by injecting casting material into vascular lumen to demonstrate real geometries of fetal cardiovascular system. Casting effectiveness was analyzed in terms of local anatomic structures and different anatomical levels (including overall level, atrioventricular and great vascular system, left-sided and right-sided heart), as well as different trimesters of pregnancy. In our study, all specimens were successfully casted. Casting effectiveness analysis of local anatomic structures showed a mean score from 1.90±1.45 to 3.60±0.52, without significant differences between case and control groups in most local anatomic structures except left ventricle, which had a higher score in control group (P=0.027). Inter-group comparison of casting effectiveness in different anatomical levels showed no significant differences between the two groups. Intra-group comparison also revealed undifferentiated casting effectiveness between atrioventricular and great vascular system, or left-sided and right-sided heart in corresponding group. Third-trimester group had a significantly higher perfusion score in great vascular system than second-trimester group (P=0.046), while the other anatomical levels displayed no such difference. Vascular corrosion technique can be successfully used in fabrication of fetal cardiovascular cast model. It is also a reliable method to demonstrate three-dimensional anatomy of severe congenital heart disease and normal heart in fetus.

Effect of reverse shoulder design philosophy on muscle moment arms.

PubMed

Hamilton, Matthew A; Diep, Phong; Roche, Chris; Flurin, Pierre Henri; Wright, Thomas W; Zuckerman, Joseph D; Routman, Howard

2015-04-01

This study analyzes the muscle moment arms of three different reverse shoulder design philosophies using a previously published method. Digital bone models of the shoulder were imported into a 3D modeling software and markers placed for the origin and insertion of relevant muscles. The anatomic model was used as a baseline for moment arm calculations. Subsequently, three different reverse shoulder designs were virtually implanted and moment arms were analyzed in abduction and external rotation. The results indicate that the lateral offset between the joint center and the axis of the humerus specific to one reverse shoulder design increased the external rotation moment arms of the posterior deltoid relative to the other reverse shoulder designs. The other muscles analyzed demonstrated differences in the moment arms, but none of the differences reached statistical significance. This study demonstrated how the combination of variables making up different reverse shoulder designs can affect the moment arms of the muscles in different and statistically significant ways. The role of humeral offset in reverse shoulder design has not been previously reported and could have an impact on external rotation and stability achieved post-operatively. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Sweat loss prediction using a multi-model approach

NASA Astrophysics Data System (ADS)

Xu, Xiaojiang; Santee, William R.

2011-07-01

A new multi-model approach (MMA) for sweat loss prediction is proposed to improve prediction accuracy. MMA was computed as the average of sweat loss predicted by two existing thermoregulation models: i.e., the rational model SCENARIO and the empirical model Heat Strain Decision Aid (HSDA). Three independent physiological datasets, a total of 44 trials, were used to compare predictions by MMA, SCENARIO, and HSDA. The observed sweat losses were collected under different combinations of uniform ensembles, environmental conditions (15-40°C, RH 25-75%), and exercise intensities (250-600 W). Root mean square deviation (RMSD), residual plots, and paired t tests were used to compare predictions with observations. Overall, MMA reduced RMSD by 30-39% in comparison with either SCENARIO or HSDA, and increased the prediction accuracy to 66% from 34% or 55%. Of the MMA predictions, 70% fell within the range of mean observed value ± SD, while only 43% of SCENARIO and 50% of HSDA predictions fell within the same range. Paired t tests showed that differences between observations and MMA predictions were not significant, but differences between observations and SCENARIO or HSDA predictions were significantly different for two datasets. Thus, MMA predicted sweat loss more accurately than either of the two single models for the three datasets used. Future work will be to evaluate MMA using additional physiological data to expand the scope of populations and conditions.

Coronary risk assessment by point-based vs. equation-based Framingham models: significant implications for clinical care.

PubMed

Gordon, William J; Polansky, Jesse M; Boscardin, W John; Fung, Kathy Z; Steinman, Michael A

2010-11-01

US cholesterol guidelines use original and simplified versions of the Framingham model to estimate future coronary risk and thereby classify patients into risk groups with different treatment strategies. We sought to compare risk estimates and risk group classification generated by the original, complex Framingham model and the simplified, point-based version. We assessed 2,543 subjects age 20-79 from the 2001-2006 National Health and Nutrition Examination Surveys (NHANES) for whom Adult Treatment Panel III (ATP-III) guidelines recommend formal risk stratification. For each subject, we calculated the 10-year risk of major coronary events using the original and point-based Framingham models, and then compared differences in these risk estimates and whether these differences would place subjects into different ATP-III risk groups (<10% risk, 10-20% risk, or >20% risk). Using standard procedures, all analyses were adjusted for survey weights, clustering, and stratification to make our results nationally representative. Among 39 million eligible adults, the original Framingham model categorized 71% of subjects as having "moderate" risk (<10% risk of a major coronary event in the next 10 years), 22% as having "moderately high" (10-20%) risk, and 7% as having "high" (>20%) risk. Estimates of coronary risk by the original and point-based models often differed substantially. The point-based system classified 15% of adults (5.7 million) into different risk groups than the original model, with 10% (3.9 million) misclassified into higher risk groups and 5% (1.8 million) into lower risk groups, for a net impact of classifying 2.1 million adults into higher risk groups. These risk group misclassifications would impact guideline-recommended drug treatment strategies for 25-46% of affected subjects. Patterns of misclassifications varied significantly by gender, age, and underlying CHD risk. Compared to the original Framingham model, the point-based version misclassifies millions of Americans into risk groups for which guidelines recommend different treatment strategies.

Validating Lung Models Using the ASL 5000 Breathing Simulator.

PubMed

Dexter, Amanda; McNinch, Neil; Kaznoch, Destiny; Volsko, Teresa A

2018-04-01

This study sought to validate pediatric models with normal and altered pulmonary mechanics. PubMed and CINAHL databases were searched for studies directly measuring pulmonary mechanics of healthy infants and children, infants with severe bronchopulmonary dysplasia and neuromuscular disease. The ASL 5000 was used to construct models using tidal volume (VT), inspiratory time (TI), respiratory rate, resistance, compliance, and esophageal pressure gleaned from literature. Data were collected for a 1-minute period and repeated three times for each model. t tests compared modeled data with data abstracted from the literature. Repeated measures analyses evaluated model performance over multiple iterations. Statistical significance was established at a P value of less than 0.05. Maximum differences of means (experimental iteration mean - clinical standard mean) for TI and VT are the following: term infant without lung disease (TI = 0.09 s, VT = 0.29 mL), severe bronchopulmonary dysplasia (TI = 0.08 s, VT = 0.17 mL), child without lung disease (TI = 0.10 s, VT = 0.17 mL), and child with neuromuscular disease (TI = 0.09 s, VT = 0.57 mL). One-sample testing demonstrated statistically significant differences between clinical controls and VT and TI values produced by the ASL 5000 for each iteration and model (P < 0.01). The greatest magnitude of differences was negligible (VT < 1.6%, TI = 18%) and not clinically relevant. Inconsistencies occurred with the models constructed on the ASL 5000. It was deemed accurate for the study purposes. It is therefore essential to test models and evaluate magnitude of differences before use.

Comparison of the effects of model-based iterative reconstruction and filtered back projection algorithms on software measurements in pulmonary subsolid nodules.

PubMed

Cohen, Julien G; Kim, Hyungjin; Park, Su Bin; van Ginneken, Bram; Ferretti, Gilbert R; Lee, Chang Hyun; Goo, Jin Mo; Park, Chang Min

2017-08-01

To evaluate the differences between filtered back projection (FBP) and model-based iterative reconstruction (MBIR) algorithms on semi-automatic measurements in subsolid nodules (SSNs). Unenhanced CT scans of 73 SSNs obtained using the same protocol and reconstructed with both FBP and MBIR algorithms were evaluated by two radiologists. Diameter, mean attenuation, mass and volume of whole nodules and their solid components were measured. Intra- and interobserver variability and differences between FBP and MBIR were then evaluated using Bland-Altman method and Wilcoxon tests. Longest diameter, volume and mass of nodules and those of their solid components were significantly higher using MBIR (p < 0.05) with mean differences of 1.1% (limits of agreement, -6.4 to 8.5%), 3.2% (-20.9 to 27.3%) and 2.9% (-16.9 to 22.7%) and 3.2% (-20.5 to 27%), 6.3% (-51.9 to 64.6%), 6.6% (-50.1 to 63.3%), respectively. The limits of agreement between FBP and MBIR were within the range of intra- and interobserver variability for both algorithms with respect to the diameter, volume and mass of nodules and their solid components. There were no significant differences in intra- or interobserver variability between FBP and MBIR (p > 0.05). Semi-automatic measurements of SSNs significantly differed between FBP and MBIR; however, the differences were within the range of measurement variability. • Intra- and interobserver reproducibility of measurements did not differ between FBP and MBIR. • Differences in SSNs' semi-automatic measurement induced by reconstruction algorithms were not clinically significant. • Semi-automatic measurement may be conducted regardless of reconstruction algorithm. • SSNs' semi-automated classification agreement (pure vs. part-solid) did not significantly differ between algorithms.

Intercomparison of Meteorological Forcing Data from Empirical and Mesoscale Model Sources in the N.F. American River Basin in northern California

NASA Astrophysics Data System (ADS)

Wayand, N. E.; Hamlet, A. F.; Hughes, M. R.; Feld, S.; Lundquist, J. D.

2012-12-01

The data required to drive distributed hydrological models is significantly limited within mountainous terrain due to a scarcity of observations. This study evaluated three common configurations of forcing data: a) one low-elevation station, combined with empirical techniques, b) gridded output from the Weather Research and Forecasting (WRF) model, and c) a combination of the two. Each configuration was evaluated within the heavily-instrumented North Fork American River Basin in northern California, during October-June 2000-2010. Simulations of streamflow and snowpack using the Distributed Hydrology Soil and Vegetation Model (DHSVM) highlighted precipitation and radiation as variables whose sources resulted in significant differences. The best source of precipitation data varied between years. On average, the performance of WRF and the single station distributed using the Parameter Regression on Independent Slopes Model (PRISM), were not significantly different. The average percent biases in simulated streamflow were 3.4% and 0.9%, for configurations a) and b) respectively, even though precipitation compared directly with gauge measurements was biased high by 6% and 17%, suggesting that gauge undercatch may explain part of the bias. Simulations of snowpack using empirically-estimated long-wave irradiance resulted in melt rates lower than those observed at high-elevation sites, while at lower-elevations the same forcing caused significant mid-winter melt that was not observed (Figure 1). These results highlight the complexity of how forcing data sources impact hydrology over different areas (high vs. low elevation snow) and different time-periods. Overall, results support the use of output from the WRF model over empirical techniques in regions with limited station data. FIG. 1. (a,b) Simulated SWE from DHSVM compared to observations at the Sierra Snow Lab (2100m) and Blue Canyon (1609m) during 2008 - 2009. Modeled (c,d) internal pack temperature, (e,f) downward short-wave irradiance, (g,h) downward long-wave irradiance, and (i,k) net-irradiance. Note that the timeperiod of plots e,g,i focus on the melt season (March-May), and plots f,h,j focus on the erroneous mid-winter melt event during January - time-periods marked with vertical dashed lines in (a) and (b).

Artificial intelligence: a new approach for prescription and monitoring of hemodialysis therapy.

PubMed

Akl, A I; Sobh, M A; Enab, Y M; Tattersall, J

2001-12-01

The effect of dialysis on patients is conventionally predicted using a formal mathematical model. This approach requires many assumptions of the processes involved, and validation of these may be difficult. The validity of dialysis urea modeling using a formal mathematical model has been challenged. Artificial intelligence using neural networks (NNs) has been used to solve complex problems without needing a mathematical model or an understanding of the mechanisms involved. In this study, we applied an NN model to study and predict concentrations of urea during a hemodialysis session. We measured blood concentrations of urea, patient weight, and total urea removal by direct dialysate quantification (DDQ) at 30-minute intervals during the session (in 15 chronic hemodialysis patients). The NN model was trained to recognize the evolution of measured urea concentrations and was subsequently able to predict hemodialysis session time needed to reach a target solute removal index (SRI) in patients not previously studied by the NN model (in another 15 chronic hemodialysis patients). Comparing results of the NN model with the DDQ model, the prediction error was 10.9%, with a not significant difference between predicted total urea nitrogen (UN) removal and measured UN removal by DDQ. NN model predictions of time showed a not significant difference with actual intervals needed to reach the same SRI level at the same patient conditions, except for the prediction of SRI at the first 30-minute interval, which showed a significant difference (P = 0.001). This indicates the sensitivity of the NN model to what is called patient clearance time; the prediction error was 8.3%. From our results, we conclude that artificial intelligence applications in urea kinetics can give an idea of intradialysis profiling according to individual clinical needs. In theory, this approach can be extended easily to other solutes, making the NN model a step forward to achieving artificial-intelligent dialysis control.

Predictors and Neuropsychiatric Profile of Nucleus Basalis of Meynert Degeneration in Parkinson Disease

DTIC Science & Technology

2017-10-01

baseline were available for 228 PD subjects. In a logistic regression model adjusted for age and sex , Ch4 density was associated with lower risk of...events, there were no significant differences in age or sex (p>0.05). PD subjects with 2 or more psychotic events had significantly lower baseline Ch4...Aim 1 and 2 include use of linear regression models to adjust for age, sex , and other significant covariates. Aim 3 is a cross-sectional controlled

Large Animal Models for Batten Disease: A Review

PubMed Central

Weber, Krystal; Pearce, David A.

2014-01-01

The neuronal ceroid lipofuscinoses, collectively referred to as Batten disease, make up a group of inherited childhood disorders that result in blindness, motor and cognitive regression, brain atrophy, and seizures, ultimately leading to premature death. So far more than 10 genes have been implicated in different forms of the neuronal ceroid lipofuscinoses. Most related research has involved mouse models, but several naturally occurring large animal models have recently been discovered. In this review, we discuss the different large animal models and their significance in Batten disease research. PMID:24014507

Modeling multi-layer effects in passive microwave remote sensing of dry snow using Dense Media Radiative Transfer Theory (DMRT) based on quasicrystalline approximation

USGS Publications Warehouse

Liang, D.; Xu, X.; Tsang, L.; Andreadis, K.M.; Josberger, E.G.

2008-01-01

The Dense Media Radiative Transfer theory (DMRT) of Quasicrystalline Approximation of Mie scattering by sticky particles is used to study the multiple scattering effects in layered snow in microwave remote sensing. Results are illustrated for various snow profile characteristics. Polarization differences and frequency dependences of multilayer snow model are significantly different from that of the single-layer snow model. Comparisons are also made with CLPX data using snow parameters as given by the VIC model. ?? 2007 IEEE.

Regional patterns of future runoff changes from Earth system models constrained by observation

NASA Astrophysics Data System (ADS)

Yang, Hui; Zhou, Feng; Piao, Shilong; Huang, Mengtian; Chen, Anping; Ciais, Philippe; Li, Yue; Lian, Xu; Peng, Shushi; Zeng, Zhenzhong

2017-06-01

In the recent Intergovernmental Panel on Climate Change assessment, multimodel ensembles (arithmetic model averaging, AMA) were constructed with equal weights given to Earth system models, without considering the performance of each model at reproducing current conditions. Here we use Bayesian model averaging (BMA) to construct a weighted model ensemble for runoff projections. Higher weights are given to models with better performance in estimating historical decadal mean runoff. Using the BMA method, we find that by the end of this century, the increase of global runoff (9.8 ± 1.5%) under Representative Concentration Pathway 8.5 is significantly lower than estimated from AMA (12.2 ± 1.3%). BMA presents a less severe runoff increase than AMA at northern high latitudes and a more severe decrease in Amazonia. Runoff decrease in Amazonia is stronger than the intermodel difference. The intermodel difference in runoff changes is mainly caused not only by precipitation differences among models, but also by evapotranspiration differences at the high northern latitudes.

A Comparative Analysis of Spatial Visualization Ability and Drafting Models for Industrial and Technology Education Students

ERIC Educational Resources Information Center

Katsioloudis, Petros; Jovanovic, Vukica; Jones, Mildred

2014-01-01

The main purpose of this study was to determine significant positive effects among the use of three different types of drafting models, and to identify whether any differences exist towards promotion of spatial visualization ability for students in Industrial Technology and Technology Education courses. In particular, the study compared the use of…

Modeling soil respiration and variations of source components using a multi-factor global climate change experiment

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

Chen, Xiongwen; Post, Wilfred M; Norby, Richard J

2011-01-01

Soil respiration is an important component of the global carbon cycle and is highly responsive to changes in soil temperature and moisture. Accurate prediction of soil respiration and its changes under future climatic conditions requires a clear understanding of the processes involved. In spite of this, most current empirical soil respiration models incorporate just few of the underlying mechanisms that may influence its response. In this study, a new partial process-based component model built on source components of soil respiration was tested using data collected from a multi-factor climate change experiment that manipulates CO2 concentrations, temperature and precipitation. These resultsmore » were then compared to results generated using several other established models. The component model we tested performed well across different treatments of global climate change. In contrast, some other models, which worked well predicting ambient environmental conditions, were unable to predict the changes under different climate change treatments. Based on the component model, the relative proportions of heterotrophic respiration (Rh) in the total soil respiration at different treatments varied from 0.33 to 0.85. There is a significant increase in the proportion of Rh under the elevated atmospheric CO2 concentration in comparison ambient conditions. The dry treatment resulted in higher proportion of Rh at elevated CO2 and ambient T than under elevated CO2 and elevated T. Also, the ratios between root growth and root maintenance respiration varied across different treatments. Neither increased temperature nor elevated atmospheric CO2 changed Q10 values significantly, while the average Q10 value at wet sites was significantly higher than it at dry sites. There was a higher possibility of increased soil respiration under drying relative to wetting conditions across all treatments based on monthly data, indicating that soil respiration may also be related to soil moisture at previous time periods. Our results reveal that the extent, time delay and contribution of different source components need to be included into mechanistic/processes-based soil respiration models at corresponding scale.« less

A Model of the Effect of Ozone Depletion on Lower-Stratospheric Structure

NASA Technical Reports Server (NTRS)

Olsen, Mark A.; Stolarski, Richard S.; Gupta, Mohan L.; Nielsen, J. Eric; Pawson, Steven

2005-01-01

We have run two twenty-year integrations of a global circulation model using 1978-1980 and 1998-2000 monthly mean ozone climatologies. The ozone climatology is used solely in the radiation scheme of the model. Several key differences between the model runs will be presented. The temperature and potential vorticity (PV) structure of the lower stratosphere, particularly in the Southern Hemisphere, is significantly changed using the 1998-2000 ozone climatology. In the Southern Hemisphere summer, the lapse rate and PV-defined polar tropopauses are both at altitudes on the order of several hundred meters greater than the 1978-1980 climatological run. The 380 K potential temperature surf= is likewise at a greater altitude. The mass of the extratropical lowermost stratosphere (between the tropopause and 380 K surface) remains unchanged. The altitude differences are not observed in the Northern Hemisphere. The different ozone fields do not produce a significant change in the annual extratropical stratosphere-troposphere exchange of mass although slight variations in the spatial distribution of the exchange exist. We are also investigating a delay in the breakup of the Southern Hemisphere polar vortex due to the differing ozone climatologies.

A normative study to evaluate inclination and angulation of teeth in North Indian population and comparision of expression of torque in preadjusted appliances

PubMed Central

Verma, Sanjeev; Singh, SP; Utreja, Ashok

2014-01-01

Aim: The aim of this study was to evaluate angulation and inclination of teeth from the study models of individuals with normal occlusion and evaluation of actual expression of torque expressed by three different bracket systems. Materials and Methods: In this study, the inclination and angulation were measured on 30 study models of North Indian individuals. A self-developed instrument (torque angle gauge) was used for the measurement. Fifteen study models were duplicated for the evaluation of torque expression in the bracket of three different manufacturers with different shape and size of bases. Results: The results give the mean, minimum and maximum, standard deviation of the normative data individually for each tooth. A significant correlation was noted in the angulation of maxillary canine and first premolar, and between premolars; and between mandibular central incisor with lateral incisor and canine, and between premolars. Conclusions: There was a highly significant correlation of teeth angulation and inclination in the maxillary and mandibular arch. Though the error in expression of torque was not significant, but it showed a large range, indicating the need to vary the position of brackets in different bracket systems for achieving optimum torque. PMID:25143932

Restricted N-glycan conformational space in the PDB and its implication in glycan structure modeling.

PubMed

Jo, Sunhwan; Lee, Hui Sun; Skolnick, Jeffrey; Im, Wonpil

2013-01-01

Understanding glycan structure and dynamics is central to understanding protein-carbohydrate recognition and its role in protein-protein interactions. Given the difficulties in obtaining the glycan's crystal structure in glycoconjugates due to its flexibility and heterogeneity, computational modeling could play an important role in providing glycosylated protein structure models. To address if glycan structures available in the PDB can be used as templates or fragments for glycan modeling, we present a survey of the N-glycan structures of 35 different sequences in the PDB. Our statistical analysis shows that the N-glycan structures found on homologous glycoproteins are significantly conserved compared to the random background, suggesting that N-glycan chains can be confidently modeled with template glycan structures whose parent glycoproteins share sequence similarity. On the other hand, N-glycan structures found on non-homologous glycoproteins do not show significant global structural similarity. Nonetheless, the internal substructures of these N-glycans, particularly, the substructures that are closer to the protein, show significantly similar structures, suggesting that such substructures can be used as fragments in glycan modeling. Increased interactions with protein might be responsible for the restricted conformational space of N-glycan chains. Our results suggest that structure prediction/modeling of N-glycans of glycoconjugates using structure database could be effective and different modeling approaches would be needed depending on the availability of template structures.

Restricted N-glycan Conformational Space in the PDB and Its Implication in Glycan Structure Modeling

PubMed Central

Jo, Sunhwan; Lee, Hui Sun; Skolnick, Jeffrey; Im, Wonpil

2013-01-01

Understanding glycan structure and dynamics is central to understanding protein-carbohydrate recognition and its role in protein-protein interactions. Given the difficulties in obtaining the glycan's crystal structure in glycoconjugates due to its flexibility and heterogeneity, computational modeling could play an important role in providing glycosylated protein structure models. To address if glycan structures available in the PDB can be used as templates or fragments for glycan modeling, we present a survey of the N-glycan structures of 35 different sequences in the PDB. Our statistical analysis shows that the N-glycan structures found on homologous glycoproteins are significantly conserved compared to the random background, suggesting that N-glycan chains can be confidently modeled with template glycan structures whose parent glycoproteins share sequence similarity. On the other hand, N-glycan structures found on non-homologous glycoproteins do not show significant global structural similarity. Nonetheless, the internal substructures of these N-glycans, particularly, the substructures that are closer to the protein, show significantly similar structures, suggesting that such substructures can be used as fragments in glycan modeling. Increased interactions with protein might be responsible for the restricted conformational space of N-glycan chains. Our results suggest that structure prediction/modeling of N-glycans of glycoconjugates using structure database could be effective and different modeling approaches would be needed depending on the availability of template structures. PMID:23516343

A Theoretical Analysis of Sex Differences In Same-Sex Friendships.

ERIC Educational Resources Information Center

Barth, Robert J.; Kinder, Bill N.

1988-01-01

Investigates sex differences in same-sex friendships of 312 undergraduate students in terms of the intersection and social penetration model of relationship development, and Bem's theory of sex role orientation. Finds significant sex-related differences in depth, duration, and involvement. (FMW)

Maternal, Infant Characteristics, Breastfeeding Techniques, and Initiation: Structural Equation Modeling Approaches

PubMed Central

Htun, Tha Pyai; Lim, Peng Im; Ho-Lim, Sarah

2015-01-01

Objectives The aim of this study was to examine the relationships among maternal and infant characteristics, breastfeeding techniques, and exclusive breastfeeding initiation in different modes of birth using structural equation modeling approaches. Methods We examined a hypothetical model based on integrating concepts of a breastfeeding decision-making model, a breastfeeding initiation model, and a social cognitive theory among 952 mother-infant dyads. The LATCH breastfeeding assessment tool was used to evaluate breastfeeding techniques and two infant feeding categories were used (exclusive and non-exclusive breastfeeding). Results Structural equation models (SEM) showed that multiparity was significantly positively associated with breastfeeding techniques and the jaundice of an infant was significantly negatively related to exclusive breastfeeding initiation. A multigroup analysis in the SEM showed no difference between the caesarean section and vaginal delivery groups estimates of breastfeeding techniques on exclusive breastfeeding initiation. Breastfeeding techniques were significantly positively associated with exclusive breastfeeding initiation in the entire sample and in the vaginal deliveries group. However, breastfeeding techniques were not significantly associated with exclusive breastfeeding initiation in the cesarean section group. Maternal age, maternal race, gestations, birth weight of infant, and postnatal complications had no significant impacts on breastfeeding techniques or exclusive breastfeeding initiation in our study. Overall, the models fitted the data satisfactorily (GFI = 0.979–0.987; AGFI = 0.951–0.962; IFI = 0.958–0.962; CFI = 0.955–0.960, and RMSEA = 0.029–0.034). Conclusions Multiparity and jaundice of an infant were found to affect breastfeeding technique and exclusive breastfeeding initiation respectively. Breastfeeding technique was related to exclusive breastfeeding initiation according to the mode of birth. This relationship implies the importance of early effective interventions among first-time mothers with jaundice infants in improving breastfeeding techniques and promoting exclusive breastfeeding initiation. PMID:26566028

Scaling depth-induced wave-breaking in two-dimensional spectral wave models

NASA Astrophysics Data System (ADS)

Salmon, J. E.; Holthuijsen, L. H.; Zijlema, M.; van Vledder, G. Ph.; Pietrzak, J. D.

2015-03-01

Wave breaking in shallow water is still poorly understood and needs to be better parameterized in 2D spectral wave models. Significant wave heights over horizontal bathymetries are typically under-predicted in locally generated wave conditions and over-predicted in non-locally generated conditions. A joint scaling dependent on both local bottom slope and normalized wave number is presented and is shown to resolve these issues. Compared to the 12 wave breaking parameterizations considered in this study, this joint scaling demonstrates significant improvements, up to ∼50% error reduction, over 1D horizontal bathymetries for both locally and non-locally generated waves. In order to account for the inherent differences between uni-directional (1D) and directionally spread (2D) wave conditions, an extension of the wave breaking dissipation models is presented. By including the effects of wave directionality, rms-errors for the significant wave height are reduced for the best performing parameterizations in conditions with strong directional spreading. With this extension, our joint scaling improves modeling skill for significant wave heights over a verification data set of 11 different 1D laboratory bathymetries, 3 shallow lakes and 4 coastal sites. The corresponding averaged normalized rms-error for significant wave height in the 2D cases varied between 8% and 27%. In comparison, using the default setting with a constant scaling, as used in most presently operating 2D spectral wave models, gave equivalent errors between 15% and 38%.

HCMM energy budget data as a model input for assessing regions of high potential groundwater pollution

NASA Technical Reports Server (NTRS)

Moore, D. G. (Principal Investigator); Heilman, J.; Tunheim, J. A.; Baumberger, V.

1978-01-01

The author has identified the following significant results. To investigate the general relationship between surface temperature and soil moisture profiles, a series of model calculations were carried out. Soil temperature profiles were calculated during a complete diurnal cycle for a variety of moisture profiles. Preliminary results indicate the surface temperature difference between two sites measured at about 1400 hours is related to the difference in soil moisture within the diurnal damping depth (about 50 cm). The model shows this temperature difference to vary considerably throughout the diurnal cycle.

Predicting risk for portal vein thrombosis in acute pancreatitis patients: A comparison of radical basis function artificial neural network and logistic regression models.

PubMed

Fei, Yang; Hu, Jian; Gao, Kun; Tu, Jianfeng; Li, Wei-Qin; Wang, Wei

2017-06-01

To construct a radical basis function (RBF) artificial neural networks (ANNs) model to predict the incidence of acute pancreatitis (AP)-induced portal vein thrombosis. The analysis included 353 patients with AP who had admitted between January 2011 and December 2015. RBF ANNs model and logistic regression model were constructed based on eleven factors relevant to AP respectively. Statistical indexes were used to evaluate the value of the prediction in two models. The predict sensitivity, specificity, positive predictive value, negative predictive value and accuracy by RBF ANNs model for PVT were 73.3%, 91.4%, 68.8%, 93.0% and 87.7%, respectively. There were significant differences between the RBF ANNs and logistic regression models in these parameters (P<0.05). In addition, a comparison of the area under receiver operating characteristic curves of the two models showed a statistically significant difference (P<0.05). The RBF ANNs model is more likely to predict the occurrence of PVT induced by AP than logistic regression model. D-dimer, AMY, Hct and PT were important prediction factors of approval for AP-induced PVT. Copyright © 2017 Elsevier Inc. All rights reserved.

The oxygen uptake slow component at submaximal intensities in breaststroke swimming

PubMed Central

Oliveira, Diogo R.; Gonçalves, Lio F.; Reis, António M.; Fernandes, Ricardo J.; Garrido, Nuno D.

2016-01-01

Abstract The present work proposed to study the oxygen uptake slow component (VO2 SC) of breaststroke swimmers at four different intensities of submaximal exercise, via mathematical modeling of a multi-exponential function. The slow component (SC) was also assessed with two different fixed interval methods and the three methods were compared. Twelve male swimmers performed a test comprising four submaximal 300 m bouts at different intensities where all expired gases were collected breath by breath. Multi-exponential modeling showed values above 450 ml·min−1 of the SC in the two last bouts of exercise (those with intensities above the lactate threshold). A significant effect of the method that was used to calculate the VO2 SC was revealed. Higher mean values were observed when using mathematical modeling compared with the fixed interval 3rd min method (F=7.111; p=0.012; η2=0.587); furthermore, differences were detected among the two fixed interval methods. No significant relationship was found between the SC determined by any method and the blood lactate measured at each of the four exercise intensities. In addition, no significant association between the SC and peak oxygen uptake was found. It was concluded that in trained breaststroke swimmers, the presence of the VO2 SC may be observed at intensities above that corresponding to the 3.5 mM-1 threshold. Moreover, mathematical modeling of the oxygen uptake on-kinetics tended to show a higher slow component as compared to fixed interval methods. PMID:28149379

Complex functionality with minimal computation: Promise and pitfalls of reduced-tracer ocean biogeochemistry models

NASA Astrophysics Data System (ADS)

Galbraith, Eric D.; Dunne, John P.; Gnanadesikan, Anand; Slater, Richard D.; Sarmiento, Jorge L.; Dufour, Carolina O.; de Souza, Gregory F.; Bianchi, Daniele; Claret, Mariona; Rodgers, Keith B.; Marvasti, Seyedehsafoura Sedigh

2015-12-01

Earth System Models increasingly include ocean biogeochemistry models in order to predict changes in ocean carbon storage, hypoxia, and biological productivity under climate change. However, state-of-the-art ocean biogeochemical models include many advected tracers, that significantly increase the computational resources required, forcing a trade-off with spatial resolution. Here, we compare a state-of-the art model with 30 prognostic tracers (TOPAZ) with two reduced-tracer models, one with 6 tracers (BLING), and the other with 3 tracers (miniBLING). The reduced-tracer models employ parameterized, implicit biological functions, which nonetheless capture many of the most important processes resolved by TOPAZ. All three are embedded in the same coupled climate model. Despite the large difference in tracer number, the absence of tracers for living organic matter is shown to have a minimal impact on the transport of nutrient elements, and the three models produce similar mean annual preindustrial distributions of macronutrients, oxygen, and carbon. Significant differences do exist among the models, in particular the seasonal cycle of biomass and export production, but it does not appear that these are necessary consequences of the reduced tracer number. With increasing CO2, changes in dissolved oxygen and anthropogenic carbon uptake are very similar across the different models. Thus, while the reduced-tracer models do not explicitly resolve the diversity and internal dynamics of marine ecosystems, we demonstrate that such models are applicable to a broad suite of major biogeochemical concerns, including anthropogenic change. These results are very promising for the further development and application of reduced-tracer biogeochemical models that incorporate "sub-ecosystem-scale" parameterizations.

Comparison of Bolton analysis and Little’s irregularity index on laser scanned three-dimensional digital study models with conventional study models

NASA Astrophysics Data System (ADS)

Kurnia, H.; Noerhadi, N. A. I.

2017-08-01

Three-dimensional digital study models were introduced following advances in digital technology. This study was carried out to assess the reliability of digital study models scanned by a laser scanning device newly assembled. The aim of this study was to compare the digital study models and conventional models. Twelve sets of dental impressions were taken from patients with mild-to-moderate crowding. The impressions were taken twice, one with alginate and the other with polyvinylsiloxane. The alginate impressions were made into conventional models, and the polyvinylsiloxane impressions were scanned to produce digital models. The mesiodistal tooth width and Little’s irregularity index (LII) were measured manually with digital calipers on the conventional models and digitally on the digital study models. Bolton analysis was performed on each study models. Each method was carried out twice to check for intra-observer variability. The reproducibility (comparison of the methods) was assessed using independent-sample t-tests. The mesiodistal tooth width between conventional and digital models did not significantly differ (p > 0.05). Independent-sample t-tests did not identify statistically significant differences for Bolton analysis and LII (p = 0.603 for Bolton and p = 0894 for LII). The measurements of the digital study models are as accurate as those of the conventional models.

Model dependence and its effect on ensemble projections in CMIP5

NASA Astrophysics Data System (ADS)

Abramowitz, G.; Bishop, C.

2013-12-01

Conceptually, the notion of model dependence within climate model ensembles is relatively simple - modelling groups share a literature base, parametrisations, data sets and even model code - the potential for dependence in sampling different climate futures is clear. How though can this conceptual problem inform a practical solution that demonstrably improves the ensemble mean and ensemble variance as an estimate of system uncertainty? While some research has already focused on error correlation or error covariance as a candidate to improve ensemble mean estimates, a complete definition of independence must at least implicitly subscribe to an ensemble interpretation paradigm, such as the 'truth-plus-error', 'indistinguishable', or more recently 'replicate Earth' paradigm. Using a definition of model dependence based on error covariance within the replicate Earth paradigm, this presentation will show that accounting for dependence in surface air temperature gives cooler projections in CMIP5 - by as much as 20% globally in some RCPs - although results differ significantly for each RCP, especially regionally. The fact that the change afforded by accounting for dependence across different RCPs is different is not an inconsistent result. Different numbers of submissions to each RCP by different modelling groups mean that differences in projections from different RCPs are not entirely about RCP forcing conditions - they also reflect different sampling strategies.

Fusing metabolomics data sets with heterogeneous measurement errors

PubMed Central

Waaijenborg, Sandra; Korobko, Oksana; Willems van Dijk, Ko; Lips, Mirjam; Hankemeier, Thomas; Wilderjans, Tom F.; Smilde, Age K.

2018-01-01

Combining different metabolomics platforms can contribute significantly to the discovery of complementary processes expressed under different conditions. However, analysing the fused data might be hampered by the difference in their quality. In metabolomics data, one often observes that measurement errors increase with increasing measurement level and that different platforms have different measurement error variance. In this paper we compare three different approaches to correct for the measurement error heterogeneity, by transformation of the raw data, by weighted filtering before modelling and by a modelling approach using a weighted sum of residuals. For an illustration of these different approaches we analyse data from healthy obese and diabetic obese individuals, obtained from two metabolomics platforms. Concluding, the filtering and modelling approaches that both estimate a model of the measurement error did not outperform the data transformation approaches for this application. This is probably due to the limited difference in measurement error and the fact that estimation of measurement error models is unstable due to the small number of repeats available. A transformation of the data improves the classification of the two groups. PMID:29698490

Comparison of Perturbed Pathways in Two Different Cell Models for Parkinson's Disease with Structural Equation Model.

PubMed

Pepe, Daniele; Do, Jin Hwan

2015-12-16

Increasing evidence indicates that different morphological types of cell death coexist in the brain of patients with Parkinson's disease (PD), but the molecular explanation for this is still under investigation. In this study, we identified perturbed pathways in two different cell models for PD through the following procedures: (1) enrichment pathway analysis with differentially expressed genes and the Reactome pathway database, and (2) construction of the shortest path model for the enriched pathway and detection of significant shortest path model with fitting time-course microarray data of each PD cell model to structural equation model. Two PD cell models constructed by the same neurotoxin showed different perturbed pathways. That is, one showed perturbation of three Reactome pathways, including cellular senescence, chromatin modifying enzymes, and chromatin organization, while six modules within metabolism pathway represented perturbation in the other. This suggests that the activation of common upstream cell death pathways in PD may result in various down-stream processes, which might be associated with different morphological types of cell death. In addition, our results might provide molecular clues for coexistence of different morphological types of cell death in PD patients.

Comparison of Approaches to the Prediction of Surface Wave Phase Velocity

NASA Astrophysics Data System (ADS)

Godfrey, K. E.; Dalton, C. A.; Hjorleifsdottir, V.; Ekstrom, G.

2017-12-01

Global seismic models provide crucial information about the state, composition, and dynamics of the Earth's interior, and in the shallow mantle these models are primarily constrained by observations of surface waves. Models developed by different groups have been constructed using different data sets and different techniques. While these models exhibit good agreement on the long-wavelength features, there is less consistency in the patterns and amplitude of smaller-scale heterogeneity. Here we investigate how approximations in the theoretical treatment of wave propagation and excitation influence the interpretation of measured phase delays and the tomographic images that result from inverting them. Synthetic seismograms were generated using SPECFEM3D_GLOBE for 42 earthquakes, 134 receiver locations, and two 3-D models of elastic Earth structure: S362ANI (Kustowski et al., 2008) and a rougher model constructed by adding realistic small-scale structure to S362ANI. Fundamental-mode Rayleigh and Love wave phase delays in the period range 35-250 seconds were measured using the approach of Ekström et al. (1997), for which PREM is the assumed reference Earth model. These measurements were compared to phase-delay predictions generated for the great-circle ray approximation, exact ray theory, and finite-frequency theory. We find that for both 3-D earth models exact ray theory provides the best fit to the measurements at short periods. At longer periods finite frequency theory provides the best fit. For the smooth earth model, the differences in fit for the various predictions are less significant at long periods than at shorter periods. The differences at long periods become more significant with increasing model roughness. In all cases, the agreement between predictions and measurements is best for paths located away from nodes in the source radiation pattern. The ability of the measured phase delays to recover the input Earth models is assessed through tests that explore the influence of parameterization, regularization, and crustal corrections.

The Apollo 16 regolith - A petrographically-constrained chemical mixing model

NASA Technical Reports Server (NTRS)

Kempa, M. J.; Papike, J. J.; White, C.

1980-01-01

A mixing model for Apollo 16 regolith samples has been developed, which differs from other A-16 mixing models in that it is both petrographically constrained and statistically sound. The model was developed using three components representative of rock types present at the A-16 site, plus a representative mare basalt. A linear least-squares fitting program employing the chi-squared test and sum of components was used to determine goodness of fit. Results for surface soils indicate that either there are no significant differences between Cayley and Descartes material at the A-16 site or, if differences do exist, they have been obscured by meteoritic reworking and mixing of the lithologies.

Ecological Determinants of Highly Pathogenic Avian Influenza (H5N1) Outbreaks in Bangladesh

PubMed Central

Ahmed, Syed S. U.; Ersbøll, Annette K.; Biswas, Paritosh K.; Christensen, Jens P.; Hannan, Abu S. M. A.; Toft, Nils

2012-01-01

Background The agro-ecology and poultry husbandry of the south Asian and south-east Asian countries share common features, however, with noticeable differences. Hence, the ecological determinants associated with risk of highly pathogenic avian influenza (HPAI-H5N1) outbreaks are expected to differ between Bangladesh and e.g., Thailand and Vietnam. The primary aim of the current study was to establish ecological determinants associated with the risk of HPAI-H5N1 outbreaks at subdistrict level in Bangladesh. The secondary aim was to explore the performance of two different statistical modeling approaches for unmeasured spatially correlated variation. Methodology/Principal Findings An ecological study at subdistrict level in Bangladesh was performed with 138 subdistricts with HPAI-H5N1 outbreaks during 2007–2008, and 326 subdistricts with no outbreaks. The association between ecological determinants and HPAI-H5N1 outbreaks was examined using a generalized linear mixed model. Spatial clustering of the ecological data was modeled using 1) an intrinsic conditional autoregressive (ICAR) model at subdistrict level considering their first order neighbors, and 2) a multilevel (ML) model with subdistricts nested within districts. Ecological determinants significantly associated with risk of HPAI-H5N1 outbreaks at subdistrict level were migratory birds' staging areas, river network, household density, literacy rate, poultry density, live bird markets, and highway network. Predictive risk maps were derived based on the resulting models. The resulting models indicate that the ML model absorbed some of the covariate effect of the ICAR model because of the neighbor structure implied in the two different models. Conclusions/Significance The study identified a new set of ecological determinants related to river networks, migratory birds' staging areas and literacy rate in addition to already known risk factors, and clarified that the generalized concept of free grazing duck and duck-rice cultivation interacted ecology are not significant determinants for Bangladesh. These findings will refine current understanding of the HPAI-H5N1 epidemiology in Bangladesh. PMID:22470496

Modeling of dispersion near roadways based on the vehicle-induced turbulence concept

NASA Astrophysics Data System (ADS)

Sahlodin, Ali M.; Sotudeh-Gharebagh, Rahmat; Zhu, Yifang

A mathematical model is developed for dispersion near roadways by incorporating vehicle-induced turbulence (VIT) into Gaussian dispersion modeling using computational fluid dynamics (CFD). The model is based on the Gaussian plume equation in which roadway is regarded as a series of point sources. The Gaussian dispersion parameters are modified by simulation of the roadway using CFD in order to evaluate turbulent kinetic energy (TKE) as a measure of VIT. The model was evaluated against experimental carbon monoxide concentrations downwind of two major freeways reported in the literature. Good agreements were achieved between model results and the literature data. A significant difference was observed between the model results with and without considering VIT. The difference is rather high for data very close to the freeways. This model, after evaluation with additional data, may be used as a framework for predicting dispersion and deposition from any roadway for different traffic (vehicle type and speed) conditions.

Effects of Individual Differences and Job Characteristics on the Psychological Health of Italian Nurses

PubMed Central

Zurlo, Maria Clelia; Vallone, Federica; Smith, Andrew P.

2018-01-01

The Demand Resources and Individual Effects Model (DRIVE Model) is a transactional model that integrates Demands- Control-Support and Effort-Reward Imbalance models emphasising the role of individual (Coping Strategies; Overcommitment) and job characteristics (Job Demands, Social Support, Decision Latitude, Skill Discretion, Effort, Rewards) in the work-related stress process. The present study aimed to test the DRIVE Model in a sample of 450 Italian nurses and to compare findings with those of a study conducted in a sample of UK nurses. A questionnaire composed of Ways of Coping Checklist-Revised (WCCL-R); Job Content Questionnaire (JCQ); ERI Test; Hospital Anxiety and Depression Scale (HADS) was used. Data supported the application of the DRIVE Model to the Italian context, showing significant associations of the individual characteristics of Problem-focused, Seek Advice and Wishful Thinking coping strategies and the job characteristics of Job Demands, Skill Discretion, Decision Latitude, and Effort with perceived levels of Anxiety and Depression. Effort represented the best predictor for psychological health conditions among Italian nurses, and Social Support significantly moderated the effects of Job Demands on perceived levels of Anxiety. The comparison study showed significant differences in the risk profiles of Italian and UK nurses. Findings were discussed in order to define focused interventions to promote nurses’ wellbeing.

Femoral curvature variability in modern humans using three-dimensional quadric surface fitting.

PubMed

Chapman, Tara; Sholukha, Victor; Semal, Patrick; Louryan, Stéphane; Rooze, Marcel; Van Sint Jan, Serge

2015-12-01

This study analysed femoral curvature in a population from Belgium in conjunction with other morphological characteristics by the use of three-dimensional (3D) quadric surfaces (QS) modelled from the bone surface. 3D models were created from computed tomography data of 75 femoral modern human bones. Anatomical landmarks (ALs) were palpated in specific bony areas of the femur (shaft, condyles, neck and head). QS were then created from the surface vertices which enclose these ALs. The diaphyseal shaft was divided into five QS shapes to analyse curvature in different parts of the shaft. Femoral bending differs in different parts of the diaphyseal shaft. The greatest degree of curvature was found in the distal shaft (mean 4.5° range 0.2°-10°) followed by the proximal (mean 4.4° range 1.5°-10.2°), proximal intermediate (mean 3.7° range 0.9°-7.9°) and distal intermediate (mean 1.8° range 0.2°-5.6°) shaft sections. The proximal and distal angles were significantly more bowed than the intermediate proximal and the intermediate distal angle. There was no significant difference between the proximal and distal angle. No significant correlations were found between morphological characteristics and femoral curvature. An extremely large variability of femoral curvature with several bones displaying very high or low degrees of femoral curvature was also found. 3D QS fitting enables the creation of accurate models which can discriminate between different patterns in similar curvatures and demonstrates there is a clear difference between curvature in different parts of the shaft.

Sensitivity of Antarctic sea ice to the Southern Annular Mode in coupled climate models

NASA Astrophysics Data System (ADS)

Holland, Marika M.; Landrum, Laura; Kostov, Yavor; Marshall, John

2017-09-01

We assess the sea ice response to Southern Annular Mode (SAM) anomalies for pre-industrial control simulations from the Coupled Model Intercomparison Project (CMIP5). Consistent with work by Ferreira et al. (J Clim 28:1206-1226, 2015. doi: 10.1175/JCLI-D-14-00313.1), the models generally simulate a two-timescale response to positive SAM anomalies, with an initial increase in ice followed by an eventual sea ice decline. However, the models differ in the cross-over time at which the change in ice response occurs, in the overall magnitude of the response, and in the spatial distribution of the response. Late twentieth century Antarctic sea ice trends in CMIP5 simulations are related in part to different modeled responses to SAM variability acting on different time-varying transient SAM conditions. This explains a significant fraction of the spread in simulated late twentieth century southern hemisphere sea ice extent trends across the model simulations. Applying the modeled sea ice response to SAM variability but driven by the observed record of SAM suggests that variations in the austral summer SAM, which has exhibited a significant positive trend, have driven a modest sea ice decrease. However, additional work is needed to narrow the considerable model uncertainty in the climate response to SAM variability and its implications for 20th-21st century trends.

Differences in passenger car and large truck involved crash frequencies at urban signalized intersections: an exploratory analysis.

PubMed

Dong, Chunjiao; Clarke, David B; Richards, Stephen H; Huang, Baoshan

2014-01-01

The influence of intersection features on safety has been examined extensively because intersections experience a relatively large proportion of motor vehicle conflicts and crashes. Although there are distinct differences between passenger cars and large trucks-size, operating characteristics, dimensions, and weight-modeling crash counts across vehicle types is rarely addressed. This paper develops and presents a multivariate regression model of crash frequencies by collision vehicle type using crash data for urban signalized intersections in Tennessee. In addition, the performance of univariate Poisson-lognormal (UVPLN), multivariate Poisson (MVP), and multivariate Poisson-lognormal (MVPLN) regression models in establishing the relationship between crashes, traffic factors, and geometric design of roadway intersections is investigated. Bayesian methods are used to estimate the unknown parameters of these models. The evaluation results suggest that the MVPLN model possesses most of the desirable statistical properties in developing the relationships. Compared to the UVPLN and MVP models, the MVPLN model better identifies significant factors and predicts crash frequencies. The findings suggest that traffic volume, truck percentage, lighting condition, and intersection angle significantly affect intersection safety. Important differences in car, car-truck, and truck crash frequencies with respect to various risk factors were found to exist between models. The paper provides some new or more comprehensive observations that have not been covered in previous studies. Copyright © 2013 Elsevier Ltd. All rights reserved.

Short note: the experimental geopotential model XGM2016

NASA Astrophysics Data System (ADS)

Pail, R.; Fecher, T.; Barnes, D.; Factor, J. F.; Holmes, S. A.; Gruber, T.; Zingerle, P.

2018-04-01

As a precursor study for the upcoming combined Earth Gravitational Model 2020 (EGM2020), the Experimental Gravity Field Model XGM2016, parameterized as a spherical harmonic series up to degree and order 719, is computed. XGM2016 shares the same combination methodology as its predecessor model GOCO05c (Fecher et al. in Surv Geophys 38(3): 571-590, 2017. doi: 10.1007/s10712-016-9406-y). The main difference between these models is that XGM2016 is supported by an improved terrestrial data set of 15^' × 15^' gravity anomaly area-means provided by the United States National Geospatial-Intelligence Agency (NGA), resulting in significant upgrades compared to existing combined gravity field models, especially in continental areas such as South America, Africa, parts of Asia, and Antarctica. A combination strategy of relative regional weighting provides for improved performance in near-coastal ocean regions, including regions where the altimetric data are mostly unchanged from previous models. Comparing cumulative height anomalies, from both EGM2008 and XGM2016 at degree/order 719, yields differences of 26 cm in Africa and 40 cm in South America. These differences result from including additional information of satellite data, as well as from the improved ground data in these regions. XGM2016 also yields a smoother Mean Dynamic Topography with significantly reduced artifacts, which indicates an improved modeling of the ocean areas.

Number and location of drainage catheter side holes: in vitro evaluation.

PubMed

Ballard, D H; Alexander, J S; Weisman, J A; Orchard, M A; Williams, J T; D'Agostino, H B

2015-09-01

To evaluate the influence of number and location of catheter shaft side holes regarding drainage efficiency in an in vitro model. Three different drainage catheter models were constructed: open-ended model with no side holes (one catheter), unilateral side hole model (six catheters with one to six unilateral side holes), and bilateral side hole model (six catheters with one to six bilateral side holes). Catheters were inserted into a drainage output-measuring device with a constant-pressure reservoir of water. The volume of water evacuated by each of the catheters at 10-second intervals was measured. A total of five trials were performed for each catheter. Data were analysed using one-way analysis of variance. The open-ended catheter had a mean drainage volume comparable to the unilateral model catheters with three, four, and five side holes. Unilateral model catheters had significant drainage volume increases up to three side holes; unilateral model catheters with more than three side holes had no significant improvement in drainage volume. All bilateral model catheters had significantly higher mean drainage volumes than their unilateral counterparts. There was no significant difference between the mean drainage volume with one, two, or three pairs of bilateral side holes. Further, there was no drainage improvement by adding additional bilateral side holes. The present in vitro study suggests that beyond a critical side hole number threshold, adding more distal side holes does not improve catheter drainage efficiency. These results may be used to enhance catheter design towards improving their drainage efficiency. Copyright © 2015 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

Bankfull discharge and channel characteristics of streams in New York State

USGS Publications Warehouse

Mulvihill, Christiane I.; Baldigo, Barry P.; Miller, Sarah J.; DeKoskie, Douglas; DuBois, Joel

2009-01-01

Equations that relate drainage area to bankfull discharge and channel characteristics (such as width, depth, and cross-sectional area) at gaged sites are needed to help define bankfull discharge and channel characteristics at ungaged sites and can be used in stream-restoration and protection projects, stream-channel classification, and channel assessments. These equations are intended to serve as a guide for streams in areas of similar hydrologic, climatic, and physiographic conditions. New York State contains eight hydrologic regions that were previously delineated on the basis of high-flow (flood) characteristics. This report seeks to increase understanding of the factors affecting bankfull discharge and channel characteristics to drainage-area size relations in New York State by providing an in-depth analysis of seven previously published regional bankfull-discharge and channel-characteristics curves.Stream-survey data and discharge records from 281 cross sections at 82 streamflow-gaging stations were used in regression analyses to relate drainage area to bankfull discharge and bankfull-channel width, depth, and cross-sectional area. The R2 and standard errors of estimate of each regional equation were compared to the R2 and standard errors of estimate for the statewide (pooled) model to determine if regionalizing data reduced model variability. It was found that regional models typically yield less variable results than those obtained using pooled statewide equations, which indicates statistically significant regional differences in bankfull-discharge and channel-characteristics relations.Statistical analysis of bankfull-discharge relations found that curves for regions 4 and 7 fell outside the 95-percent confidence interval bands of the statewide model and had intercepts that were significantly diferent (p≤0.10) from the other five hydrologic regions.Analysis of channel-characteristics relations found that the bankfull width, depth, and cross-sectional area curves for region 3 were significantly different p(≤0.05) from the other six regions.It was hypothesized that some regional variability could be reduced by creating models for streams with similar physiographic and climatic characteristics. Available data on streamflow patterns and previous regional-curve research suggested that mean annual runoff, Rosgen stream type, and water-surface slope were the variables most likely to influence regional bankfull discharge and channel characteristics to drainage-area size relations. Results showed that although all of these factors had an influence on regional relations, most stratified models have lower 2 values and higher standard errors of estimate than the regional models.The New York statewide (pooled) bankfull-discharge equation and equations for regions 4 and 7 were compared with equations for four other regions in the Northeast to evaluate region-to-region differences, and assess the ability of individual curves to produce results more accurate than those that would be obtained from one model of the northeastern United States. Results indicated that model slopes lack significant diferences, though intercepts are significantly different. Comparison of bankfull-discharge estimates using different models shows that results could vary by as much as 100 percent depending on which model was used and indicated that regionalization improved model accuracy.

Wave-vector and polarization dependent impedance model for a hexagonal periodic metasurface exemplified through finite-difference time-domain simulations.

PubMed

Ding, Yi S; He, Yang

2017-08-21

An isotropic impedance sheet model is proposed for a loop-type hexagonal periodic metasurface. Both frequency and wave-vector dispersion are considered near the resonance frequency. Therefore both the angle and polarization dependences of the metasurface impedance can be properly and simultaneously described in our model. The constitutive relation of this model is transformed into auxiliary differential equations which are integrated into the finite-difference time-domain algorithm. Finally, a finite large metasurface sample under oblique illumination is used to test the model and the algorithm. Our model and algorithm can significantly increase the accuracy of the homogenization methods for modeling periodic metasurfaces.

Nonlinear spherical perturbations in quintessence models of dark energy

NASA Astrophysics Data System (ADS)

Pratap Rajvanshi, Manvendra; Bagla, J. S.

2018-06-01

Observations have confirmed the accelerated expansion of the universe. The accelerated expansion can be modelled by invoking a cosmological constant or a dynamical model of dark energy. A key difference between these models is that the equation of state parameter w for dark energy differs from ‑1 in dynamical dark energy (DDE) models. Further, the equation of state parameter is not constant for a general DDE model. Such differences can be probed using the variation of scale factor with time by measuring distances. Another significant difference between the cosmological constant and DDE models is that the latter must cluster. Linear perturbation analysis indicates that perturbations in quintessence models of dark energy do not grow to have a significant amplitude at small length scales. In this paper we study the response of quintessence dark energy to non-linear perturbations in dark matter. We use a fully relativistic model for spherically symmetric perturbations. In this study we focus on thawing models. We find that in response to non-linear perturbations in dark matter, dark energy perturbations grow at a faster rate than expected in linear perturbation theory. We find that dark energy perturbation remains localised and does not diffuse out to larger scales. The dominant drivers of the evolution of dark energy perturbations are the local Hubble flow and a supression of gradients of the scalar field. We also find that the equation of state parameter w changes in response to perturbations in dark matter such that it also becomes a function of position. The variation of w in space is correlated with density contrast for matter. Variation of w and perturbations in dark energy are more pronounced in response to large scale perturbations in matter while the dependence on the amplitude of matter perturbations is much weaker.

Comparison of the occlusal contact area of virtual models and actual models: a comparative in vitro study on Class I and Class II malocclusion models.

PubMed

Lee, Hyemin; Cha, Jooly; Chun, Youn-Sic; Kim, Minji

2018-06-19

The occlusal registration of virtual models taken by intraoral scanners sometimes shows patterns which seem much different from the patients' occlusion. Therefore, this study aims to evaluate the accuracy of virtual occlusion by comparing virtual occlusal contact area with actual occlusal contact area using a plaster model in vitro. Plaster dental models, 24 sets of Class I models and 20 sets of Class II models, were divided into a Molar, Premolar, and Anterior group. The occlusal contact areas calculated by the Prescale method and the virtual occlusion by scanning method were compared, and the ratio of the molar and incisor area were compared in order to find any particular tendencies. There was no significant difference between the Prescale results and the scanner results in both the molar and premolar groups (p = 0.083 and 0.053, respectively). On the other hand, there was a significant difference between the Prescale and the scanner results in the anterior group with the scanner results presenting overestimation of the occlusal contact points (p < 0.05). In Molars group, the regression analysis shows that the two variables express linear correlation and has a linear equation with a slope of 0.917. R 2 is 0.930. Groups of Premolars and Anteriors had a week linear relationship and greater dispersion. Difference between the actual and virtual occlusion revealed in the anterior portion, where overestimation was observed in the virtual model obtained from the scanning method. Nevertheless, molar and premolar areas showed relatively accurate occlusal contact area in the virtual model.

Firefly algorithm versus genetic algorithm as powerful variable selection tools and their effect on different multivariate calibration models in spectroscopy: A comparative study.

PubMed

Attia, Khalid A M; Nassar, Mohammed W I; El-Zeiny, Mohamed B; Serag, Ahmed

2017-01-05

For the first time, a new variable selection method based on swarm intelligence namely firefly algorithm is coupled with three different multivariate calibration models namely, concentration residual augmented classical least squares, artificial neural network and support vector regression in UV spectral data. A comparative study between the firefly algorithm and the well-known genetic algorithm was developed. The discussion revealed the superiority of using this new powerful algorithm over the well-known genetic algorithm. Moreover, different statistical tests were performed and no significant differences were found between all the models regarding their predictabilities. This ensures that simpler and faster models were obtained without any deterioration of the quality of the calibration. Copyright © 2016 Elsevier B.V. All rights reserved.

Association of Interarm Systolic Blood Pressure Difference with Atherosclerosis and Left Ventricular Hypertrophy

PubMed Central

Su, Ho-Ming; Lin, Tsung-Hsien; Hsu, Po-Chao; Chu, Chun-Yuan; Lee, Wen-Hsien; Chen, Szu-Chia; Lee, Chee-Siong; Voon, Wen-Chol; Lai, Wen-Ter; Sheu, Sheng-Hsiung

2012-01-01

An interarm systolic blood pressure (SBP) difference of 10 mmHg or more have been associated with peripheral artery disease and adverse cardiovascular outcomes. We investigated whether an association exists between this difference and ankle-brachial index (ABI), brachial-ankle pulse wave velocity (baPWV), and echocardiographic parameters. A total of 1120 patients were included in the study. The bilateral arm blood pressures were measured simultaneously by an ABI-form device. The values of ABI and baPWV were also obtained from the same device. Clinical data, ABI<0.9, baPWV, echocariographic parameters, and an interarm SBP difference ≥10 mmHg were compared and analyzed. We performed two multivariate forward analyses for determining the factors associated with an interarm SBP difference ≥10 mmHg [model 1: significant variables in univariate analysis except left ventricular mass index (LVMI); model 2: significant variables in univariate analysis except ABI<0.9 and baPWV]. The ABI<0.9 and high baPWV in model 1 and high LVMI in model 2 were independently associated with an interarm SBP difference ≥10 mmHg. Female, hypertension, and high body mass index were also associated with an interarm SBP difference ≥10 mmHg. Our study demonstrated that ABI<0.9, high baPWV, and high LVMI were independently associated with an interarm SBP difference of 10 mmHg or more. Detection of an interarm SBP difference may provide a simple method of detecting patients at increased risk of atherosclerosis and left ventricular hypertrophy. PMID:22927905

Southern California Permanent GPS Geodetic Array: Continuous measurements of regional crustal deformation between the 1992 Landers and 1994 Northridge earthquakes

USGS Publications Warehouse

Bock, Y.; Wdowinski, S.; Fang, P.; Zhang, Jiahua; Williams, S.; Johnson, H.; Behr, J.; Genrich, J.; Dean, J.; Van Domselaar, M.; Agnew, D.; Wyatt, F.; Stark, K.; Oral, B.; Hudnut, K.; King, R.; Herring, T.; Dinardo, S.; Young, W.; Jackson, D.; Gurtner, W.

1997-01-01

The southern California Permanent GPS Geodetic Array (PGGA) was established in 1990 across the Pacific-North America plate boundary to continuously monitor crustal deformation. We describe the development of the array and the time series of daily positions estimated for its first 10 sites in the 19-month period between the June 28, 1992 (Mw=7.3), Landers and January 17, 1994 (Mw=6.7), Northridge earthquakes. We compare displacement rates at four site locations with those reported by Feigl et al. [1993], which were derived from an independent set of Global Positioning System (GPS) and very long baseline interferometry (VLBI) measurements collected over nearly a decade prior to the Landers earthquake. The velocity differences for three sites 65-100 km from the earthquake's epicenter are of order of 3-5 mm/yr and are systematically coupled with the corresponding directions of coseismic displacement. The fourth site, 300 km from the epicenter, shows no significant velocity difference. These observations suggest large-scale postseismic deformation with a relaxation time of at least 800 days. The statistical significance of our observations is complicated by our incomplete knowledge of the noise properties of the two data sets; two possible noise models fit the PGGA data equally well as described in the companion paper by Zhang et al. [this issue]; the pre-Landers data are too sparse and heterogeneous to derive a reliable noise model. Under a fractal white noise model for the PGGA data we find that the velocity differences for all three sites are statistically different at the 99% significance level. A white noise plus flicker noise model results in significance levels of only 94%, 43%, and 88%. Additional investigations of the pre-Landers data, and analysis of longer spans of PGGA data, could have an important effect on the significance of these results and will be addressed in future work. Copyright 1997 by the American Geophysical Union.

Large differences in regional precipitation change between a first and second 2 K of global warming

DOE PAGES

Good, Peter; Booth, Ben B. B.; Chadwick, Robin; ...

2016-12-06

For adaptation and mitigation planning, stakeholders need reliable information about regional precipitation changes under different emissions scenarios and for different time periods. A significant amount of current planning effort assumes that each K of global warming produces roughly the same regional climate change. By using 25 climate models, we compare precipitation responses with three 2 K intervals of global ensemble mean warming: a fast and a slower route to a first 2 K above pre-industrial levels, and the end-of-century difference between high-emission and mitigation scenarios. Here, we show that, although the two routes to a first 2 K give verymore » similar precipitation changes, a second 2 K produces quite a different response. In particular, the balance of physical mechanisms responsible for climate model uncertainty is different for a first and a second 2 K of warming. Our results are consistent with a significant influence from nonlinear physical mechanisms, but aerosol and land-use effects may be important regionally.« less

Large differences in regional precipitation change between a first and second 2 K of global warming.

PubMed

Good, Peter; Booth, Ben B B; Chadwick, Robin; Hawkins, Ed; Jonko, Alexandra; Lowe, Jason A

2016-12-06

For adaptation and mitigation planning, stakeholders need reliable information about regional precipitation changes under different emissions scenarios and for different time periods. A significant amount of current planning effort assumes that each K of global warming produces roughly the same regional climate change. Here using 25 climate models, we compare precipitation responses with three 2 K intervals of global ensemble mean warming: a fast and a slower route to a first 2 K above pre-industrial levels, and the end-of-century difference between high-emission and mitigation scenarios. We show that, although the two routes to a first 2 K give very similar precipitation changes, a second 2 K produces quite a different response. In particular, the balance of physical mechanisms responsible for climate model uncertainty is different for a first and a second 2 K of warming. The results are consistent with a significant influence from nonlinear physical mechanisms, but aerosol and land-use effects may be important regionally.

[Torque resistance of three different types of nickel-titanium rotary instruments].

PubMed

Sun, Wei; Hou, Ben-xiang

2010-10-01

To compare torsional fracture of three different types of nickel-titanium rotary instruments ProTaper, Hero642 and Mtwo by making a stimulate models in vitro. Through the establishment of model in vitro, compared the different time with 3 kinds of nickel titanium file in cutting-edge bound occurs, and to observe the section of fractured instruments by scanning electron microscope. The resistence to torque was different from three types of nickel titanium instruments. The time to fracture of Mtwo was significantly longer than ProTaper's and Hero642's, but ProTaper's and Hero642's had no significant difference. Three kinds cross-sectional design were different, a lot of toughness nests were seen in broken surface. Most of them were ductile fracture. Time to fracture was influenced by the quality disfigurement. The resistance to torque of Mtwo was better than ProTaper and Hero642. The lifespan was influenced by the design of cross-section. The quality disfigurement of the files reduced the resistance to flexual fatigue.

Large differences in regional precipitation change between a first and second 2 K of global warming

NASA Astrophysics Data System (ADS)

Good, Peter; Booth, Ben B. B.; Chadwick, Robin; Hawkins, Ed; Jonko, Alexandra; Lowe, Jason A.

2016-12-01

For adaptation and mitigation planning, stakeholders need reliable information about regional precipitation changes under different emissions scenarios and for different time periods. A significant amount of current planning effort assumes that each K of global warming produces roughly the same regional climate change. Here using 25 climate models, we compare precipitation responses with three 2 K intervals of global ensemble mean warming: a fast and a slower route to a first 2 K above pre-industrial levels, and the end-of-century difference between high-emission and mitigation scenarios. We show that, although the two routes to a first 2 K give very similar precipitation changes, a second 2 K produces quite a different response. In particular, the balance of physical mechanisms responsible for climate model uncertainty is different for a first and a second 2 K of warming. The results are consistent with a significant influence from nonlinear physical mechanisms, but aerosol and land-use effects may be important regionally.

Large differences in regional precipitation change between a first and second 2 K of global warming

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

Good, Peter; Booth, Ben B. B.; Chadwick, Robin

For adaptation and mitigation planning, stakeholders need reliable information about regional precipitation changes under different emissions scenarios and for different time periods. A significant amount of current planning effort assumes that each K of global warming produces roughly the same regional climate change. By using 25 climate models, we compare precipitation responses with three 2 K intervals of global ensemble mean warming: a fast and a slower route to a first 2 K above pre-industrial levels, and the end-of-century difference between high-emission and mitigation scenarios. Here, we show that, although the two routes to a first 2 K give verymore » similar precipitation changes, a second 2 K produces quite a different response. In particular, the balance of physical mechanisms responsible for climate model uncertainty is different for a first and a second 2 K of warming. Our results are consistent with a significant influence from nonlinear physical mechanisms, but aerosol and land-use effects may be important regionally.« less

International comparison of observation-specific spatial buffers: maximizing the ability to estimate physical activity.

PubMed

Frank, Lawrence D; Fox, Eric H; Ulmer, Jared M; Chapman, James E; Kershaw, Suzanne E; Sallis, James F; Conway, Terry L; Cerin, Ester; Cain, Kelli L; Adams, Marc A; Smith, Graham R; Hinckson, Erica; Mavoa, Suzanne; Christiansen, Lars B; Hino, Adriano Akira F; Lopes, Adalberto A S; Schipperijn, Jasper

2017-01-23

Advancements in geographic information systems over the past two decades have increased the specificity by which an individual's neighborhood environment may be spatially defined for physical activity and health research. This study investigated how different types of street network buffering methods compared in measuring a set of commonly used built environment measures (BEMs) and tested their performance on associations with physical activity outcomes. An internationally-developed set of objective BEMs using three different spatial buffering techniques were used to evaluate the relative differences in resulting explanatory power on self-reported physical activity outcomes. BEMs were developed in five countries using 'sausage,' 'detailed-trimmed,' and 'detailed,' network buffers at a distance of 1 km around participant household addresses (n = 5883). BEM values were significantly different (p < 0.05) for 96% of sausage versus detailed-trimmed buffer comparisons and 89% of sausage versus detailed network buffer comparisons. Results showed that BEM coefficients in physical activity models did not differ significantly across buffering methods, and in most cases BEM associations with physical activity outcomes had the same level of statistical significance across buffer types. However, BEM coefficients differed in significance for 9% of the sausage versus detailed models, which may warrant further investigation. Results of this study inform the selection of spatial buffering methods to estimate physical activity outcomes using an internationally consistent set of BEMs. Using three different network-based buffering methods, the findings indicate significant variation among BEM values, however associations with physical activity outcomes were similar across each buffering technique. The study advances knowledge by presenting consistently assessed relationships between three different network buffer types and utilitarian travel, sedentary behavior, and leisure-oriented physical activity outcomes.

Difference of the associations between self-rated health and demographic characteristics, lifestyle, and psychosocial work environment between two types of Chinese worksite.

PubMed

Jia, Yingnan; Gao, Junling; Dai, Junming; Zheng, Pinpin; Wu, Xiaoyu; Li, Guangyao; Fu, Hua

2014-08-15

Although studies of self-rated health (SRH) are conducted widely in developed countries, comprehensive assessments of the determinants of SRH in Chinese are scarce, particularly for working Chinese individuals. Determinants of SRH might differ among worksites based on differences in the nature and stress associated with different jobs, work intensity, and the lifestyles of employees. Two thousand and forty questionnaires that addressed SRH, demographic characteristics, lifestyle, and the psychosocial work environment were administered to employees at two worksites. A total of 1644 subjects provided complete data for analysis (80.6% response rate). Participants from government departments had significantly better SRH than did those from high-tech enterprises (61.1% vs. 67.5%, respectively). Lifestyles were significantly less healthy at government departments compared with high-tech enterprises, whereas the psychosocial work environment was better. The results of unadjusted and adjusted models revealed differences between the potential health-influencing factors of participants based on their type of worksite. In logistic regression models, gender was strongly associated with SRH in all participants, whereas length of service was correlated with SRH only in participants from high-tech enterprises. In high-tech enterprises, good SRH was less common in physically inactive subjects vs. physically active participants (OR = 0.561). In government departments, passive smoking was negatively associated with SRH significantly. Social capital (OR = 1.073) and job control (OR = 1.550) were positively correlated with SRH in high-tech enterprises. Job control was the only psychosocial factor significantly associated with SRH in government departments. Participants from different types of worksite reported different SRH, healthy lifestyles, and psychosocial work environments. Moreover, the association between SRH and demographic characteristics, lifestyle, and the psychosocial work environment significantly differed by type of worksite.

Pre-slaughter sound levels and pre-slaughter handling from loading at the farm till slaughter influence pork quality.

PubMed

Vermeulen, L; Van de Perre, V; Permentier, L; De Bie, S; Verbeke, G; Geers, R

2016-06-01

This study investigates the relationship between sound levels, pre-slaughter handling during loading and pork quality. Pre-slaughter variables were investigated from loading till slaughter. A total of 3213 pigs were measured 30 min post-mortem for pH(30LT) (M. Longissimus thoracis). First, a sound level model for the risk to develop PSE meat was established. The difference in maximum and mean sound level during loading, mean sound level during lairage and mean sound level prior to stunning remained significant within the model. This indicated that sound levels during loading had a significant added value to former sound models. Moreover, this study completed the global classification checklist (Vermeulen et al., 2015a) by developing a linear mixed model for pH(30LT) and PSE prevalence, with the difference in maximum and mean sound level measured during loading, the feed withdrawal period and the difference in temperature during loading and lairage. Hence, this study provided new insights over previous research where loading procedures were not included. Copyright © 2016 Elsevier Ltd. All rights reserved.

Socioeconomic Disparities in Telephone-Based Treatment of Tobacco Dependence

PubMed Central

Varghese, Merilyn; Stitzer, Maxine; Landes, Reid; Brackman, S. Laney; Munn, Tiffany

2014-01-01

Objectives. We examined socioeconomic disparities in tobacco dependence treatment outcomes from a free, proactive telephone counseling quitline. Methods. We delivered cognitive–behavioral treatment and nicotine patches to 6626 smokers and examined socioeconomic differences in demographic, clinical, environmental, and treatment use factors. We used logistic regressions and generalized estimating equations (GEE) to model abstinence and account for socioeconomic differences in the models. Results. The odds of achieving long-term abstinence differed by socioeconomic status (SES). In the GEE model, the odds of abstinence for the highest SES participants were 1.75 times those of the lowest SES participants. Logistic regression models revealed no treatment outcome disparity at the end of treatment, but significant disparities 3 and 6 months after treatment. Conclusions. Although quitlines often increase access to treatment for some lower SES smokers, significant socioeconomic disparities in treatment outcomes raise questions about whether current approaches are contributing to tobacco-related socioeconomic health disparities. Strategies to improve treatment outcomes for lower SES smokers might include novel methods to address multiple factors associated with socioeconomic disparities. PMID:24922165

Fractal Viscous Fingering in Fracture Networks

NASA Astrophysics Data System (ADS)

Boyle, E.; Sams, W.; Ferer, M.; Smith, D. H.

2007-12-01

We have used two very different physical models and computer codes to study miscible injection of a low- viscosity fluid into a simple fracture network, where it displaces a much-more viscous "defending" fluid through "rock" that is otherwise impermeable. The one code (NETfLow) is a standard pore level model, originally intended to treat laboratory-scale experiments; it assumes negligible mixing of the two fluids. The other code (NFFLOW) was written to treat reservoir-scale engineering problems; It explicitly treats the flow through the fractures and allows for significant mixing of the fluids at the interface. Both codes treat the fractures as parallel plates, of different effective apertures. Results are presented for the composition profiles from both codes. Independent of the degree of fluid-mixing, the profiles from both models have a functional form identical to that for fractal viscous fingering (i.e., diffusion limited aggregation, DLA). The two codes that solve the equations for different models gave similar results; together they suggest that the injection of a low-viscosity fluid into large- scale fracture networks may be much more significantly affected by fractal fingering than previously illustrated.

Effects of implant angulation, impression material, and variation in arch curvature width on implant transfer model accuracy.

PubMed

Akalin, Zerrin Fidan; Ozkan, Yasemin Kulak; Ekerim, Ahmet

2013-01-01

The effects of implant angulation, impression material, and variation in width of the arch curvature on transfer models were evaluated. Three edentulous maxillary epoxy resin models were fabricated, and six internal-connection implant analogs were placed in different locations and different angulations in each model. In the first model, implants were positioned in the canine, first premolar, and first molar regions, and all analogs were positioned parallel to each other and perpendicular to the horizontal crestal plane (parallel model). In the second model, analogs were positioned in same regions (canine, first premolar, and first molar), but three of them were positioned with 10-degree buccal angulations (versus the horizontal crestal plane) (angular model). In the third model, analogs were inserted in the lateral incisor, canine, and second molar regions and parallel to each other (wide-arch model). Eighteen impressions of each model were made with each of the three materials--condensation silicone, polyvinyl siloxane, and polyether--and impressions were poured and kept at room temperature for 24 hours. They were then observed under a toolmaker's microscope, with epoxy resin models of each group used as references. Distance deformations between implants in each model in the x- and y-axes were recorded separately. Implant angulation deformations were recorded in the x-z plane. Statistical evaluations were performed with analysis of variance and the least significant difference post hoc test. Angular model measurements showed the greatest deformation values (P < .05). All impression materials showed deformation, and the polyether impression models showed statistically significantly less deformation in angular measurements (P < .05). The models with implants placed parallel to each other exhibited greater accuracy than a model with implants placed at angles to each other.

Effects of physical education, extracurricular sports activities, and leisure satisfaction on adolescent aggressive behavior: A latent growth modeling approach

PubMed Central

Park, Sanghyun; Chiu, Weisheng

2017-01-01

The present study aimed to investigate the longitudinal influence of physical education classes, extracurricular sports activities, and leisure satisfaction on aggressive behavior among South Korean adolescents. Data were drawn from the Korea Youth Panel Survey. We used latent growth curve modeling to explain the growth trajectory of adolescent aggressive behaviors and a multi-group analysis to investigate gender differences in aggressive behavior. The results indicated that adolescents’ aggressive behavior significantly changed with age. There were significant gender-based differences in the level of and changes in aggressive behavior over time. Both extracurricular sports activities and leisure satisfaction had significant influences on the changes in adolescents’ aggressive behavior with age, whereas physical education classes did not. PMID:28410365

Mathematics teachers' conceptions about modelling activities and its reflection on their beliefs about mathematics

NASA Astrophysics Data System (ADS)

Shahbari, Juhaina Awawdeh

2018-07-01

The current study examines whether the engagement of mathematics teachers in modelling activities and subsequent changes in their conceptions about these activities affect their beliefs about mathematics. The sample comprised 52 mathematics teachers working in small groups in four modelling activities. The data were collected from teachers' Reports about features of each activity, interviews and questionnaires on teachers' beliefs about mathematics. The findings indicated changes in teachers' conceptions about the modelling activities. Most teachers referred to the first activity as a mathematical problem but emphasized only the mathematical notions or the mathematical operations in the modelling process; changes in their conceptions were gradual. Most of the teachers referred to the fourth activity as a mathematical problem and emphasized features of the whole modelling process. The results of the interviews indicated that changes in the teachers' conceptions can be attributed to structure of the activities, group discussions, solution paths and elicited models. These changes about modelling activities were reflected in teachers' beliefs about mathematics. The quantitative findings indicated that the teachers developed more constructive beliefs about mathematics after engagement in the modelling activities and that the difference was significant, however there was no significant difference regarding changes in their traditional beliefs.

Enhancing performance of P300-Speller under mental workload by incorporating dual-task data during classifier training.

PubMed

Chen, Yuqian; Ke, Yufeng; Meng, Guifang; Jiang, Jin; Qi, Hongzhi; Jiao, Xuejun; Xu, Minpeng; Zhou, Peng; He, Feng; Ming, Dong

2017-12-01

As one of the most important brain-computer interface (BCI) paradigms, P300-Speller was shown to be significantly impaired once applied in practical situations due to effects of mental workload. This study aims to provide a new method of building training models to enhance performance of P300-Speller under mental workload. Three experiment conditions based on row-column P300-Speller paradigm were performed including speller-only, 3-back-speller and mental-arithmetic-speller. Data under dual-task conditions were introduced to speller-only data respectively to build new training models. Then performance of classifiers with different models was compared under the same testing condition. The results showed that when tasks of imported training data and testing data were the same, character recognition accuracies and round accuracies of P300-Speller with mixed-data training models significantly improved (FDR, p < 0.005). When they were different, performance significantly improved when tested on mental-arithmetic-speller (FDR, p < 0.05) while the improvement was modest when tested on n-back-speller (FDR, p < 0.1). The analysis of ERPs revealed that ERP difference between training data and testing data was significantly diminished when the dual-task data was introduced to training data (FDR, p < 0.05). The new method of training classifier on mixed data proved to be effective in enhancing performance of P300-Speller under mental workload, confirmed the feasibility to build a universal training model and overcome the effects of mental workload in its practical applications. Copyright © 2017 Elsevier B.V. All rights reserved.

Detection and attribution of vegetation greening trend in China over the last 30 years.

PubMed

Piao, Shilong; Yin, Guodong; Tan, Jianguang; Cheng, Lei; Huang, Mengtian; Li, Yue; Liu, Ronggao; Mao, Jiafu; Myneni, Ranga B; Peng, Shushi; Poulter, Ben; Shi, Xiaoying; Xiao, Zhiqiang; Zeng, Ning; Zeng, ZhenZhong; Wang, Yingping

2015-04-01

The reliable detection and attribution of changes in vegetation growth is a prerequisite for the development of strategies for the sustainable management of ecosystems. This is an extraordinary challenge. To our knowledge, this study is the first to comprehensively detect and attribute a greening trend in China over the last three decades. We use three different satellite-derived Leaf Area Index (LAI) datasets for detection as well as five different process-based ecosystem models for attribution. Rising atmospheric CO2 concentration and nitrogen deposition are identified as the most likely causes of the greening trend in China, explaining 85% and 41% of the average growing-season LAI trend (LAIGS) estimated by satellite datasets (average trend of 0.0070 yr(-1), ranging from 0.0035 yr(-1) to 0.0127 yr(-1)), respectively. The contribution of nitrogen deposition is more clearly seen in southern China than in the north of the country. Models disagree about the contribution of climate change alone to the trend in LAIGS at the country scale (one model shows a significant increasing trend, whereas two others show significant decreasing trends). However, the models generally agree on the negative impacts of climate change in north China and Inner Mongolia and the positive impact in the Qinghai-Xizang plateau. Provincial forest area change tends to be significantly correlated with the trend of LAIGS (P < 0.05), and marginally significantly (P = 0.07) correlated with the residual of LAIGS trend, calculated as the trend observed by satellite minus that estimated by models through considering the effects of climate change, rising CO2 concentration and nitrogen deposition, across different provinces. This result highlights the important role of China's afforestation program in explaining the spatial patterns of trend in vegetation growth. © 2014 John Wiley & Sons Ltd.

Evaluation of different mathematical models and different b-value ranges of diffusion-weighted imaging in peripheral zone prostate cancer detection using b-value up to 4500 s/mm2

PubMed Central

Feng, Zhaoyan; Min, Xiangde; Margolis, Daniel J. A.; Duan, Caohui; Chen, Yuping; Sah, Vivek Kumar; Chaudhary, Nabin; Li, Basen; Ke, Zan; Zhang, Peipei; Wang, Liang

2017-01-01

Objectives To evaluate the diagnostic performance of different mathematical models and different b-value ranges of diffusion-weighted imaging (DWI) in peripheral zone prostate cancer (PZ PCa) detection. Methods Fifty-six patients with histologically proven PZ PCa who underwent DWI-magnetic resonance imaging (MRI) using 21 b-values (0–4500 s/mm2) were included. The mean signal intensities of the regions of interest (ROIs) placed in benign PZs and cancerous tissues on DWI images were fitted using mono-exponential, bi-exponential, stretched-exponential, and kurtosis models. The b-values were divided into four ranges: 0–1000, 0–2000, 0–3200, and 0–4500 s/mm2, grouped as A, B, C, and D, respectively. ADC, , D*, f, DDC, α, Dapp, and Kapp were estimated for each group. The adjusted coefficient of determination (R2) was calculated to measure goodness-of-fit. Receiver operating characteristic curve analysis was performed to evaluate the diagnostic performance of the parameters. Results All parameters except D* showed significant differences between cancerous tissues and benign PZs in each group. The area under the curve values (AUCs) of ADC were comparable in groups C and D (p = 0.980) and were significantly higher than those in groups A and B (p< 0.05 for all). The AUCs of ADC and Kapp in groups B and C were similar (p = 0.07 and p = 0.954), and were significantly higher than the other parameters (p< 0.001 for all). The AUCs of ADC in group D was slightly higher than Kapp (p = 0.002), and both were significantly higher than the other parameters (p< 0.001 for all). Conclusions ADC derived from conventional mono-exponential high b-value (3200 s/mm2) models is an optimal parameter for PZ PCa detection. PMID:28199367

Discrete dynamical system modelling for gene regulatory networks of 5-hydroxymethylfurfural tolerance for ethanologenic yeast.

PubMed

Song, M; Ouyang, Z; Liu, Z L

2009-05-01

Composed of linear difference equations, a discrete dynamical system (DDS) model was designed to reconstruct transcriptional regulations in gene regulatory networks (GRNs) for ethanologenic yeast Saccharomyces cerevisiae in response to 5-hydroxymethylfurfural (HMF), a bioethanol conversion inhibitor. The modelling aims at identification of a system of linear difference equations to represent temporal interactions among significantly expressed genes. Power stability is imposed on a system model under the normal condition in the absence of the inhibitor. Non-uniform sampling, typical in a time-course experimental design, is addressed by a log-time domain interpolation. A statistically significant DDS model of the yeast GRN derived from time-course gene expression measurements by exposure to HMF, revealed several verified transcriptional regulation events. These events implicate Yap1 and Pdr3, transcription factors consistently known for their regulatory roles by other studies or postulated by independent sequence motif analysis, suggesting their involvement in yeast tolerance and detoxification of the inhibitor.

The sensitivity of ecosystem service models to choices of input data and spatial resolution

USGS Publications Warehouse

Bagstad, Kenneth J.; Cohen, Erika; Ancona, Zachary H.; McNulty, Steven; Sun, Ge

2018-01-01

Although ecosystem service (ES) modeling has progressed rapidly in the last 10–15 years, comparative studies on data and model selection effects have become more common only recently. Such studies have drawn mixed conclusions about whether different data and model choices yield divergent results. In this study, we compared the results of different models to address these questions at national, provincial, and subwatershed scales in Rwanda. We compared results for carbon, water, and sediment as modeled using InVEST and WaSSI using (1) land cover data at 30 and 300 m resolution and (2) three different input land cover datasets. WaSSI and simpler InVEST models (carbon storage and annual water yield) were relatively insensitive to the choice of spatial resolution, but more complex InVEST models (seasonal water yield and sediment regulation) produced large differences when applied at differing resolution. Six out of nine ES metrics (InVEST annual and seasonal water yield and WaSSI) gave similar predictions for at least two different input land cover datasets. Despite differences in mean values when using different data sources and resolution, we found significant and highly correlated results when using Spearman's rank correlation, indicating consistent spatial patterns of high and low values. Our results confirm and extend conclusions of past studies, showing that in certain cases (e.g., simpler models and national-scale analyses), results can be robust to data and modeling choices. For more complex models, those with different output metrics, and subnational to site-based analyses in heterogeneous environments, data and model choices may strongly influence study findings.

Oxaliplatin but Not Irinotecan Impairs Posthepatectomy Liver Regeneration in a Murine Model

PubMed Central

Soriano, Perry A.; Liu, Nian; Castillo, Erick; Foster, Brock; Artinyan, Avo; Kim, Joseph; Huang, Wendong; Wagman, Lawrence D.

2011-01-01

Introduction. We examined the murine hepatectomy model of liver regeneration (LR) in the setting of neoadjuvant chemotherapy. Methods. C57BL/6 mice were randomized to receive neoadjuvant intraperitoneal (IP) injections of a control, oxaliplatin (15 mg/kg), or irinotecan (100 mg/Kg or 250 mg/Kg) solution. Hepatectomy (70%) was performed 14 days after the final IP treatment. Animals were sacrificed at postoperative day (D) 0, 1, 2, 3, and 7. Liver remnants and serum were collected for analysis. T-tests for independent samples were used for statistical comparisons. Results. For oxaliplatin, percent LR did not differ at D1 or D2 but was significantly less at D3 (89.0% versus 70.0%, P = 0.048) with no difference on D7 (P = 0.21). Irinotecan-treated mice at both dose levels (100 mg/Kg and 250 mg/Kg) showed no significant differences in LR. BrdU incorporation was significantly decreased in oxaliplatin-treated animals (D1,2,3). Conclusions. Neoadjuvant oxaliplatin but not irinotecan impairs early LR in a posthepatectomy murine model which correlates with decreased DNA synthesis. PMID:22164336

Efficacy of keratinocyte growth factor (palifermin) for the treatment of caustic esophageal burns

PubMed Central

NUMANOĞLU, KEMAL VARIM; TATLI, DUYGU; BEKTAŞ, SIBEL; ER, EBUBEKIR

2014-01-01

Current treatment strategies against the development of corrosive esophageal strictures remain unsatisfactory. Thus, the aim of the present study was to investigate the efficacy of keratinocyte growth factor, in the form of palifermin, for the prevention of stricture development following esophageal caustic injuries in a rat model. A total of 32 female Wistar albino rats were divided into four groups, which included the control (C), burn (B), steroid (S) and steroid plus palifermin (S/P) groups. An experimental corrosive esophageal burn model was established in the B, S and S/P groups. Weight gain was recorded and histopathological evaluation was performed for each group. Weight gain in the S and B groups was compared with the control group and statistically significant differences were observed. In addition, statistically significant differences in weight gain were observed between the S/P group and the B group. Histopathologically, statistically significant differences were identified with regard to submucosal collagen deposition, muscularis mucosa and tunica muscularis damage when comparing the B group with the C group. In addition, statistically significant differences were observed when comparing the S and S/P groups with the B group. Furthermore, significant submucosal collagen deposition and tunica muscularis damage were observed in the S group when compared with the S/P group. The stenosis indexes in the C and S groups were significantly lower compared with the B group. In addition, the stenosis index in the S/P group was significantly lower compared with the S group. To the best of our knowledge, the present study is the first to investigate the effect of palifermin on corrosive esophageal burns. The addition of palifermin to the corrosive esophageal burn standard treatment regimen was found to reduce the degree of fibrosis and ameliorate histopathological damage in an experimental model of corrosive esophagitis in rats. PMID:25187801

Non-linear dual-phase-lag model for analyzing heat transfer phenomena in living tissues during thermal ablation.

PubMed

Kumar, P; Kumar, Dinesh; Rai, K N

2016-08-01

In this article, a non-linear dual-phase-lag (DPL) bio-heat transfer model based on temperature dependent metabolic heat generation rate is derived to analyze the heat transfer phenomena in living tissues during thermal ablation treatment. The numerical solution of the present non-linear problem has been done by finite element Runge-Kutta (4,5) method which combines the essence of Runge-Kutta (4,5) method together with finite difference scheme. Our study demonstrates that at the thermal ablation position temperature predicted by non-linear and linear DPL models show significant differences. A comparison has been made among non-linear DPL, thermal wave and Pennes model and it has been found that non-linear DPL and thermal wave bio-heat model show almost same nature whereas non-linear Pennes model shows significantly different temperature profile at the initial stage of thermal ablation treatment. The effect of Fourier number and Vernotte number (relaxation Fourier number) on temperature profile in presence and absence of externally applied heat source has been studied in detail and it has been observed that the presence of externally applied heat source term highly affects the efficiency of thermal treatment method. Copyright © 2016 Elsevier Ltd. All rights reserved.

Comparison of three strong ion models used for quantifying the acid-base status of human plasma with special emphasis on the plasma weak acids.

PubMed

Anstey, Chris M

2005-06-01

Currently, three strong ion models exist for the determination of plasma pH. Mathematically, they vary in their treatment of weak acids, and this study was designed to determine whether any significant differences exist in the simulated performance of these models. The models were subjected to a "metabolic" stress either in the form of variable strong ion difference and fixed weak acid effect, or vice versa, and compared over the range 25 < or = Pco(2) < or = 135 Torr. The predictive equations for each model were iteratively solved for pH at each Pco(2) step, and the results were plotted as a series of log(Pco(2))-pH titration curves. The results were analyzed for linearity by using ordinary least squares regression and for collinearity by using correlation. In every case, the results revealed a linear relationship between log(Pco(2)) and pH over the range 6.8 < or = pH < or = 7.8, and no significant difference between the curve predictions under metabolic stress. The curves were statistically collinear. Ultimately, their clinical utility will be determined both by acceptance of the strong ion framework for describing acid-base physiology and by the ease of measurement of the independent model parameters.

Evaluation of a Local Anesthesia Simulation Model with Dental Students as Novice Clinicians.

PubMed

Lee, Jessica S; Graham, Roseanna; Bassiur, Jennifer P; Lichtenthal, Richard M

2015-12-01

The aim of this study was to evaluate the use of a local anesthesia (LA) simulation model in a facilitated small group setting before dental students administered an inferior alveolar nerve block (IANB) for the first time. For this pilot study, 60 dental students transitioning from preclinical to clinical education were randomly assigned to either an experimental group (N=30) that participated in a small group session using the simulation model or a control group (N=30). After administering local anesthesia for the first time, students in both groups were given questionnaires regarding levels of preparedness and confidence when administering an IANB and level of anesthesia effectiveness and pain when receiving an IANB. Students in the experimental group exhibited a positive difference on all six questions regarding preparedness and confidence when administering LA to another student. One of these six questions ("I was prepared in administering local anesthesia for the first time") showed a statistically significant difference (p<0.05). Students who received LA from students who practiced on the simulation model also experienced fewer post-injection complications one day after receiving the IANB, including a statistically significant reduction in trismus. No statistically significant difference was found in level of effectiveness of the IANB or perceived levels of pain between the two groups. The results of this pilot study suggest that using a local anesthesia simulation model may be beneficial in increasing a dental student's level of comfort prior to administering local anesthesia for the first time.

The Relationship Between Exclusions from Gambling Arcades and Accessibility: Evidence from a Newly Introduced Exclusion Program in Hesse, Germany.

PubMed

Strohäker, Tanja; Becker, Tilman

2018-02-28

An exclusion system for gambling arcades has been introduced recently in the state of Hesse. The aim of this paper is to identify significant predictors that are useful in explaining the variation of exclusions between different Hessian communities. Next to socio-demographic factors, we control for three different accessibility variables in two models: the number of electronic gambling machines (EGMs) in model I, and the number of locations and density of gambling machines at a location in model II. We disentangle the association between EGMs and exclusions of model I into a location and a clustering effect. Considering the socio-demographic variables, the explanatory power of our cross-sectional models is rather low. Only the age group of the 30-39 years old and those who are not in a partnership (in model I) yield significant results. As self-exclusion systems reduce availability for the group of vulnerable players, this analysis provides evidence for the assumption that the two groups-pathological gamblers and vulnerable players-seem to have little overlap concerning sociodemographic characteristics. The accessibility variables, on the other hand, turn out to be significantly associated with the number of exclusions. All three of them are statistically significant and their association is positive. The results of model II show that the location effect is more pronounced then the clustering effect of EGMs, i.e. the effect of an additional single-licensed arcade on the number of exclusions is stronger than the increase in the number of license at one location.

A statistical assessment of seismic models of the U.S. continental crust using Bayesian inversion of ambient noise surface wave dispersion data

NASA Astrophysics Data System (ADS)

Olugboji, T. M.; Lekic, V.; McDonough, W.

2017-07-01

We present a new approach for evaluating existing crustal models using ambient noise data sets and its associated uncertainties. We use a transdimensional hierarchical Bayesian inversion approach to invert ambient noise surface wave phase dispersion maps for Love and Rayleigh waves using measurements obtained from Ekström (2014). Spatiospectral analysis shows that our results are comparable to a linear least squares inverse approach (except at higher harmonic degrees), but the procedure has additional advantages: (1) it yields an autoadaptive parameterization that follows Earth structure without making restricting assumptions on model resolution (regularization or damping) and data errors; (2) it can recover non-Gaussian phase velocity probability distributions while quantifying the sources of uncertainties in the data measurements and modeling procedure; and (3) it enables statistical assessments of different crustal models (e.g., CRUST1.0, LITHO1.0, and NACr14) using variable resolution residual and standard deviation maps estimated from the ensemble. These assessments show that in the stable old crust of the Archean, the misfits are statistically negligible, requiring no significant update to crustal models from the ambient noise data set. In other regions of the U.S., significant updates to regionalization and crustal structure are expected especially in the shallow sedimentary basins and the tectonically active regions, where the differences between model predictions and data are statistically significant.

Examining the Digital Divide between Rural and Urban Schools: Technology Availability, Teachers' Integration Level and Students' Perception

ERIC Educational Resources Information Center

Wang, Pei-Yu

2013-01-01

This study aimed to explore the gap regarding technology integration between urban and rural schools based on the Will Skill Tool model. This study was guided by three main questions: 1) Is there any significant difference in terms of technology availability between rural and urban elementary schools?; 2) Is there any significant difference in…

Uncertainties in Episodic Ozone Modeling Stemming from Uncertainties in the Meteorological Fields.

NASA Astrophysics Data System (ADS)

Biswas, Jhumoor; Trivikrama Rao, S.

2001-02-01

This paper examines the uncertainty associated with photochemical modeling using the Variable-Grid Urban Airshed Model (UAM-V) with two different prognostic meteorological models. The meteorological fields for ozone episodes that occurred during 17-20 June, 12-15 July, and 30 July-2 August in the summer of 1995 were derived from two meteorological models, the Regional Atmospheric Modeling System (RAMS) and the Fifth-Generation Pennsylvania State University-National Center for Atmospheric Research Mesoscale Model (MM5). The simulated ozone concentrations from the two photochemical modeling systems, namely, RAMS/UAM-V and MM5/UAM-V, are compared with each other and with ozone observations from several monitoring sites in the eastern United States. The overall results indicate that neither modeling system performs significantly better than the other in reproducing the observed ozone concentrations. The results reveal that there is a significant variability, about 20% at the 95% level of confidence, in the modeled 1-h ozone concentration maxima from one modeling system to the other for a given episode. The model-to-model variability in the simulated ozone levels is for most part attributable to the unsystematic type of errors. The directionality for emission controls (i.e., NOx versus VOC sensitivity) is also evaluated with UAM-V using hypothetical emission reductions. The results reveal that not only the improvement in ozone but also the VOC-sensitive and NOx-sensitive regimes are influenced by the differences in the meteorological fields. Both modeling systems indicate that a large portion of the eastern United States is NOx limited, but there are model-to-model and episode-to-episode differences at individual grid cells regarding the efficacy of emission reductions.

Effect of different impression materials and techniques on the dimensional accuracy of implant definitive casts.

PubMed

Ebadian, Behnaz; Rismanchian, Mansor; Dastgheib, Badrosadat; Bajoghli, Farshad

2015-01-01

Different factors such as impression techniques and materials can affect the passive fit between the superstructure and implant. The aim of this study was to determine the effect of different impression materials and techniques on the dimensional accuracy of implant definitive casts. Four internal hex implants (Biohorizons Ø4 mm) were placed on a metal maxillary model perpendicular to the horizontal plane in maxillary lateral incisors, right canine and left first premolar areas. Three impression techniques including open tray, closed tray using ball top screw abutments and closed tray using short impression copings and two impression materials (polyether and polyvinyl siloxane) were evaluated (n = 60). The changes in distances between implant analogues in mediolateral (x) and anteroposterior (y) directions and analogue angles in x/z and y/z directions in the horizontal plane on the definitive casts were measured by coordinate measuring machine. The data were analyzed by multivariate two-way analysis of variance and one sample t-test (α = 0.05). No statistical significant differences were observed between different impression techniques and materials. However, deviation and distortion of definitive casts had a significant difference with the master model when short impression copings and polyvinyl siloxane impression material were used (P < 0.05). In open tray technique, there was a significant difference in the rotation of analogs compared with the master model with both impression materials (P < 0.05). There was no difference between open and closed tray impression techniques; however, less distortion and deviation were observed in the open tray technique. In the closed tray impression technique, ball top screw was more accurate than short impression copings.

Effect of different impression materials and techniques on the dimensional accuracy of implant definitive casts

PubMed Central

Ebadian, Behnaz; Rismanchian, Mansor; Dastgheib, Badrosadat; Bajoghli, Farshad

2015-01-01

Background: Different factors such as impression techniques and materials can affect the passive fit between the superstructure and implant. The aim of this study was to determine the effect of different impression materials and techniques on the dimensional accuracy of implant definitive casts. Materials and Methods: Four internal hex implants (Biohorizons Ø4 mm) were placed on a metal maxillary model perpendicular to the horizontal plane in maxillary lateral incisors, right canine and left first premolar areas. Three impression techniques including open tray, closed tray using ball top screw abutments and closed tray using short impression copings and two impression materials (polyether and polyvinyl siloxane) were evaluated (n = 60). The changes in distances between implant analogues in mediolateral (x) and anteroposterior (y) directions and analogue angles in x/z and y/z directions in the horizontal plane on the definitive casts were measured by coordinate measuring machine. The data were analyzed by multivariate two-way analysis of variance and one sample t-test (α = 0.05). Results: No statistical significant differences were observed between different impression techniques and materials. However, deviation and distortion of definitive casts had a significant difference with the master model when short impression copings and polyvinyl siloxane impression material were used (P < 0.05). In open tray technique, there was a significant difference in the rotation of analogs compared with the master model with both impression materials (P < 0.05). Conclusion: There was no difference between open and closed tray impression techniques; however, less distortion and deviation were observed in the open tray technique. In the closed tray impression technique, ball top screw was more accurate than short impression copings. PMID:25878678

Friction-term response to boundary-condition type in flow models

USGS Publications Warehouse

Schaffranek, R.W.; Lai, C.

1996-01-01

The friction-slope term in the unsteady open-channel flow equations is examined using two numerical models based on different formulations of the governing equations and employing different solution methods. The purposes of the study are to analyze, evaluate, and demonstrate the behavior of the term in a set of controlled numerical experiments using varied types and combinations of boundary conditions. Results of numerical experiments illustrate that a given model can respond inconsistently for the identical resistance-coefficient value under different types and combinations of boundary conditions. Findings also demonstrate that two models employing different dependent variables and solution methods can respond similarly for the identical resistance-coefficient value under similar types and combinations of boundary conditions. Discussion of qualitative considerations and quantitative experimental results provides insight into the proper treatment, evaluation, and significance of the friction-slope term, thereby offering practical guidelines for model implementation and calibration.

A comparison of different strategies in multivariate regression models for the direct determination of Mn, Cr, and Ni in steel samples using laser-induced breakdown spectroscopy

NASA Astrophysics Data System (ADS)

Luna, Aderval S.; Gonzaga, Fabiano B.; da Rocha, Werickson F. C.; Lima, Igor C. A.

2018-01-01

Laser-induced breakdown spectroscopy (LIBS) analysis was carried out on eleven steel samples to quantify the concentrations of chromium, nickel, and manganese. LIBS spectral data were correlated to known concentrations of the samples using different strategies in partial least squares (PLS) regression models. For the PLS analysis, one predictive model was separately generated for each element, while different approaches were used for the selection of variables (VIP: variable importance in projection and iPLS: interval partial least squares) in the PLS model to quantify the contents of the elements. The comparison of the performance of the models showed that there was no significant statistical difference using the Wilcoxon signed rank test. The elliptical joint confidence region (EJCR) did not detect systematic errors in these proposed methodologies for each metal.

Adenoviral Mediated Gene Transfer of IGF-1 Enhances Wound Healing and Induces Angiogenesis

PubMed Central

Balaji, S.; LeSaint, M.; Bhattacharya, S. S.; Moles, C.; Dhamija, Y.; Kidd, M.; Le, L.D.; King, A.; Shaaban, A.; Crombleholme, T. M.; Bollyky, P.; Keswani, S. G.

2014-01-01

Background Chronic wounds are characterized by a wound healing and neovascularization deficit. Strategies to increase neovascularization can significantly improve chronic wound healing. Insulin like growth factor (IGF-1) is reported to be a keratinocyte mitogen and is believed to induce angiogenesis via a vascular endothelial growth factor (VEGF) dependent pathway. Using a novel ex vivo human dermal wound model and a diabetic impaired wound healing murine model, we hypothesized that adenoviral over expression of IGF-1 (Ad-IGF-1) will enhance wound healing and induce angiogenesis through a VEGF dependent pathway. Methods Ex vivo: 6 mm full thickness punch biopsies were obtained from normal human skin, and 3 mm full thickness wounds were created at the center. Skin explants were maintained at air liquid interface. Db/db murine model: 8 mm full thickness dorsal wounds in diabetic (db/db) mice were created. Treatment groups in both human ex vivo and in vivo db/db wound models include 1×108 PFU of Ad-IGF-1 or Ad-LacZ, and PBS (n=4–5/group). Cytotoxicity (LDH) was quantified at days 3, 5 and 7 for the human ex vivo wound model. Epithelial gap closure (H&E; Trichrome), VEGF expression (ELISA) and capillary density (CD 31+ CAPS/HPF) were analyzed at day 7. Results In the human ex vivo organ culture, the adenoviral vectors did not demonstrate any significant difference in cytotoxicity compared to PBS. Ad-IGF-1 over expression significantly increases basal keratinocyte migration, with no significant effect on epithelial gap closure. There was a significant increase in capillary density in the Ad-IGF-1 wounds. However, there was no effect on VEGF levels in Ad-IGF-1 samples compared to controls. In db/db wounds, Ad-IGF-1 over expression significantly improves epithelial gap closure and granulation tissue with a dense cellular infiltrate compared to controls. Ad-IGF-1 also increases capillary density, again with no significant difference in VEGF levels in the wounds compared to control treatments. Conclusions In two different models, our data demonstrates that adenoviral mediated gene transfer of IGF-1 results in enhanced wound healing and induces angiogenesis via a VEGF-independent pathway. Understanding the underlying mechanisms of IGF-1 effects on angiogenesis may help produce novel therapeutics for chronic wounds or diseases characterized by a deficit in neovascularization. PMID:24725678

Enhanced Precision of the New Hologic Horizon Model Compared With the Old Discovery Model Is Less Evident When Fewer Vertebrae Are Included in the Analysis.

PubMed

McNamara, Elizabeth A; Kilim, Holly P; Malabanan, Alan O; Whittaker, LaTarsha G; Rosen, Harold N

The International Society for Clinical Densitometry guidelines recommend using locally derived precision data for spine bone mineral densities (BMDs), but do not specify whether data derived from L1-L4 spines correctly reflect the precision for spines reporting fewer than 4 vertebrae. Our experience suggested that the decrease in precision with successively fewer vertebrae is progressive as more vertebrae are excluded and that the precision for the newer Horizon Hologic model might be better than that for the previous model, and we sought to quantify. Precision studies were performed on Hologic densitometers by acquiring spine BMD in fast array mode twice on 30 patients, according to International Society for Clinical Densitometry guidelines. This was done 10 different times on various Discovery densitometers, and once on a Horizon densitometer. When 1 vertebral body was excluded from analysis, there was no significant deterioration in precision. When 2 vertebrae were excluded, there was a nonsignificant trend to poorer precision, and when 3 vertebrae were excluded, there was significantly worse precision. When 3 or 4 vertebrae were reported, the precision of the spine BMD measurement was significantly better on the Hologic Horizon than on the Discovery, but the difference in precision between densitometers narrowed and was no longer significant when 1 or 2 vertebrae were reported. The results suggest that (1) the measurement of in vivo spine BMD on the new Hologic Horizon densitometer is significantly more precise than on the older Discovery model; (2) the difference in precision between the Horizon and Discovery models decreases as fewer vertebrae are included; (3) the measurement of spine BMD is less precise as more vertebrae are excluded, but still quite reasonable even when only 1 vertebral body is included; and (4) when 3 vertebrae are reported, L1-L4 precision data can reasonably be used to report significance of changes in BMD. When 1 or 2 vertebrae are reported, precision data for 1 or 2 vertebrae, respectively, should be used, because the exclusion of 2-3 vertebrae significantly worsens precision. Copyright © 2016 International Society for Clinical Densitometry. Published by Elsevier Inc. All rights reserved.

Monitoring Quality Across Home Visiting Models: A Field Test of Michigan's Home Visiting Quality Assurance System.

PubMed

Heany, Julia; Torres, Jennifer; Zagar, Cynthia; Kostelec, Tiffany

2018-06-05

Introduction In order to achieve the positive outcomes with parents and children demonstrated by many home visiting models, home visiting services must be well implemented. The Michigan Home Visiting Initiative developed a tool and procedure for monitoring implementation quality across models referred to as Michigan's Home Visiting Quality Assurance System (MHVQAS). This study field tested the MHVQAS. This article focuses on one of the study's evaluation questions: Can the MHVQAS be applied across models? Methods Eight local implementing agencies (LIAs) from four home visiting models (Healthy Families America, Early Head Start-Home Based, Parents as Teachers, Maternal Infant Health Program) and five reviewers participated in the study by completing site visits, tracking their time and costs, and completing surveys about the process. LIAs also submitted their most recent review by their model developer. The researchers conducted participant observation of the review process. Results Ratings on the MHVQAS were not significantly different between models. There were some differences in interrater reliability and perceived reliability between models. There were no significant differences between models in perceived validity, satisfaction with the review process, or cost to participate. Observational data suggested that cross-model applicability could be improved by assisting sites in relating the requirements of the tool to the specifics of their model. Discussion The MHVQAS shows promise as a tool and process to monitor implementation quality of home visiting services across models. The results of the study will be used to make improvements before the MHVQAS is used in practice.

Testing Strategies for Model-Based Development

NASA Technical Reports Server (NTRS)

Heimdahl, Mats P. E.; Whalen, Mike; Rajan, Ajitha; Miller, Steven P.

2006-01-01

This report presents an approach for testing artifacts generated in a model-based development process. This approach divides the traditional testing process into two parts: requirements-based testing (validation testing) which determines whether the model implements the high-level requirements and model-based testing (conformance testing) which determines whether the code generated from a model is behaviorally equivalent to the model. The goals of the two processes differ significantly and this report explores suitable testing metrics and automation strategies for each. To support requirements-based testing, we define novel objective requirements coverage metrics similar to existing specification and code coverage metrics. For model-based testing, we briefly describe automation strategies and examine the fault-finding capability of different structural coverage metrics using tests automatically generated from the model.

Detecting the differences in responses of stomatal conductance to moisture stresses between deciduous shrubs and Artemisia subshrubs.

PubMed

Gao, Qiong; Yu, Mei; Zhou, Chan

2013-01-01

Shrubs and subshrubs can tolerate wider ranges of moisture stresses in both soil and air than other plant life forms, and thus represent greater nonlinearity and uncertainty in ecosystem physiology. The objectives of this paper are to model shrub/subshrub stomatal conductance by synthesizing the field leaf gas exchanges data of 24 species in China, in order to detect the differences between deciduous shrubs and Artemisia subshrubs in their responses of stomatal conductance to changes in the moisture stresses. We revised a model of stomatal conductance by incorporating the tradeoff between xylem hydraulic efficiency and cavitation loss risk. We then fit the model at the three hierarchical levels: global (pooling all data as a single group), three functional groups (deciduous non-legume shrubs, deciduous legume shrubs, and subshrubs in Artemisia genus), and individual observations (species × sites). Bayesian inference with Markov Chain Monte Carlo method was applied to obtain the model parameters at the three levels. We found that the model at the level of functional groups is a significant improvement over that at the global level, indicating the significant differences in the stomatal behavior among the three functional groups. The differences in tolerance and sensitivities to changes in moisture stresses are the most evident between the shrubs and the subshrubs: The two shrub groups can tolerate much higher soil water stress than the subshrubs. The analysis at the observation level is also a significant improvement over that at the functional group level, indicating great variations within each group. Our analysis offered a clue for the equivocal issue of shrub encroachment into grasslands: While the invasion by the shrubs may be irreversible, the dominance of subshrubs, due to their lower resistance and tolerance to moisture stresses, may be put down by appropriate grassland management.

Evaluating wave-current interaction in an urban estuary and flooding implications for coastal communities

NASA Astrophysics Data System (ADS)

Cifuentes-Lorenzen, A.; O'Donnell, J.; Howard-Strobel, M. M.; Fake, T.; McCardell, G.

2016-12-01

Accurate hydrodynamic-wave coupled coastal circulation models aid the prediction of storm impacts, particularly in areas where data is absent, and can inform mitigation options. They are essential everywhere to account for the effects of climate change. Here, the Finite Volume Community Ocean Model (FVCOM) was used to estimate the residual circulation inside a small urban estuary, Long Island Sound, during three severe weather events of different magnitude (i.e. 1/5, 1/25 and 1/50 year events). The effect of including wave coupling using a log-layer bottom boundary and the bottom wave-current coupling, following the approach of Madsen (1994) on the simulated residual circulation was assessed. Significant differences in the solutions were constrained to the near surface (s>-0.3) region. No significant difference in the depth-averaged residual circulation was detected. When the Madsen (1994) bottom boundary layer model for wave-current interaction was employed, differences in residual circulation resulted. The bottom wave-current interaction also plays an important role in the wave dynamics. Significant wave heights along the northern Connecticut shoreline were enhanced by up to 15% when the bottom wave-current interaction was included in the simulations. The wave-induced bottom drag enhancement has a substantial effect on tides in the Sound, possibly because it is nearly resonant at semidiurnal frequencies. This wave-current interaction current leads to severe tidal dampening ( 40% amplitude reduction) at the Western end of the estuary in the modeled sea surface displacement. The potential magnitude of these effects means that wave current interaction should be included and carefully evaluated in models of estuaries that are useful.

Preventive Effect of Phosphodiesterase Inhibitor Pentoxifylline Against Medication-Related Osteonecrosis of the Jaw: An Animal Study.

PubMed

Yalcin-Ulker, Gül Merve; Cumbul, Alev; Duygu-Capar, Gonca; Uslu, Ünal; Sencift, Kemal

2017-11-01

The aim of this experimental study was to investigate the prophylactic effect of pentoxifylline (PTX) on medication-related osteonecrosis of the jaw (MRONJ). Female Sprague-Dawley rats (n = 33) received zoledronic acid (ZA) for 8 weeks to create an osteonecrosis model. The left mandibular second molars were extracted and the recovery period lasted 8 weeks before sacrifice. PTX was intraperitoneally administered to prevent MRONJ. The specimens were histopathologically and histomorphometrically evaluated. Histomorphometrically, between the control and ZA groups, there was no statistically significant difference in total bone volume (P = .999), but there was a statistically significant difference in bone ratio in the extraction sockets (P < .001). A comparison of the bone ratio of the ZA group with the ZA/PTX group (PTX administered after extraction) showed no statistically significant difference (P = .69), but there was a statistically significant difference with the ZA/PTX/PTX group (PTX administered before and after extraction; P = .008). Histopathologically, between the control and ZA groups, there were statistically significant differences for inflammation (P = .013), vascularization (P = .022), hemorrhage (P = .025), and regeneration (P = .008). Between the ZA and ZA/PTX groups, there were no statistically significant differences for inflammation (P = .536), vascularization (P = .642), hemorrhage (P = .765), and regeneration (P = .127). Between the ZA and ZA/PTX/PTX groups, there were statistically significant differences for inflammation (P = .017), vascularization (P = .04), hemorrhage (P = .044), and regeneration (P = .04). In this experimental model of MRONJ, it might be concluded that although PTX, given after tooth extraction, improves new bone formation that positively affects bone healing, it is not prophylactic. However, PTX given before tooth extraction is prophylactic. Therefore, PTX might affect healing in a positive way by optimizing the inflammatory response. Copyright © 2017 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Relative strength of tailor's bunion osteotomies and fixation techniques.

PubMed

Haddon, Todd B; LaPointe, Stephan J

2013-01-01

A paucity of data is available on the mechanical strength of fifth metatarsal osteotomies. The present study was designed to provide that information. Five osteotomies were mechanically tested to failure using a materials testing machine and compared with an intact fifth metatarsal using a hollow saw bone model with a sample size of 10 for each construct. The osteotomies tested were the distal reverse chevron fixated with a Kirschner wire, the long plantar reverse chevron osteotomy fixated with 2 screws, a mid-diaphyseal sagittal plane osteotomy fixated with 2 screws, the mid-diaphyseal sagittal plane osteotomy fixated with 2 screws, and an additional cerclage wire and a transverse closing wedge osteotomy fixated with a box wire technique. Analysis of variance was performed, resulting in a statistically significant difference among the data at p <.0001. The Tukey-Kramer honestly significant difference with least significant differences was performed post hoc to separate out the pairs at a minimum α of 0.05. The chevron was statistically the strongest construct at 130 N, followed by the long plantar osteotomy at 78 N. The chevron compared well with the control at 114 N, and they both fractured at the proximal model to fixture interface. The other osteotomies were statistically and significantly weaker than both the chevron and the long plantar constructs, with no statistically significant difference among them at 36, 39, and 48 N. In conclusion, the chevron osteotomy was superior in strength to the sagittal and transverse plane osteotomies and similar in strength and failure to the intact model. Copyright © 2013 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

Gender, family, and the nutritional status of children in three culturally contrasting states of India.

PubMed

Griffiths, Paula; Matthews, Zoë; Hinde, Andrew

2002-09-01

This paper has three main aims: to measure the clustering of children with low weight for age z-scores within families, to establish whether significant differences exist by gender in weight for age z-scores, and to demonstrate whether the presence of a mother-in-law in the household has any significant impact on the nutritional status of young children. Regression modelling is used to examine the weight for age z-scores of children under the age of four years in Maharashtra, Tamil Nadu and Uttar Pradesh using the 1992-93 Indian National Family Health Survey data. Random effects models measure the clustering of children with low weight for age z-scores in families, controlling for a number of other family factors. Our findings do not reveal significant gender differences in weight for age z-scores. Although little variation was found between family structures in the nutritional status of children, there were significant differences between families after controlling for family type. This suggests that there are differences between families that cannot be explained by a cross-sectional demographic survey. The evidence from this work suggests that nutrition programs need to adopt community nutrition interventions that aim resources at young children from families where children with low weight for age z-scores are found to cluster. However, there is a need for further inter-disciplinary research to collect data from families on behavioural factors and resource allocation in order that we might better understand why some families are more prone to having children with low weight for age z-scores. The diversity in the significant covariates between the three states in the models has shown the need for Indian nutrition programs to adopt state-specific approaches to tackling malnutrition.

Is a Three-Dimensional Printing Model Better Than a Traditional Cardiac Model for Medical Education? A Pilot Randomized Controlled Study.

PubMed

Wang, Zhongmin; Liu, Yuhao; Luo, Hongxing; Gao, Chuanyu; Zhang, Jing; Dai, Yuya

2017-11-01

Three-dimensional (3D) printing is a newly-emerged technology converting a series of two-dimensional images to a touchable 3D model, but no studies have investigated whether or not a 3D printing model is better than a traditional cardiac model for medical education. A 3D printing cardiac model was generated using multi-slice computed tomography datasets. Thirty-four medical students were randomized to either the 3D Printing Group taught with the aid of a 3D printing cardiac model or the Traditional Model Group with a commonly used plastic cardiac model. Questionnaires with 10 medical questions and 3 evaluative questions were filled in by the students. A 3D printing cardiac model was successfully generated. Students in the 3D Printing Group were slightly quicker to answer all questions when compared with the Traditional Model Group (224.53 ± 44.13 s vs. 238.71 ± 68.46 s, p = 0.09), but the total score was not significantly different (6.24 ± 1.30 vs. 7.18 ± 1.70, p = 0.12). Neither the students'satisfaction (p = 0.48) nor their understanding of cardiac structures (p = 0.24) was significantly different between two groups. More students in the 3D Printing Group believed that they had understood at least 90% of teaching content (6 vs. 1). Both groups had 12 (70.6%) students who preferred a 3D printing model for medical education. A 3D printing model was not significantly superior to a traditional model in teaching cardiac diseases in our pilot randomized controlled study, yet more studies may be conducted to validate the real effect of 3D printing on medical education.

Is a Three-Dimensional Printing Model Better Than a Traditional Cardiac Model for Medical Education? A Pilot Randomized Controlled Study

PubMed Central

Wang, Zhongmin; Liu, Yuhao; Luo, Hongxing; Gao, Chuanyu; Zhang, Jing; Dai, Yuya

2017-01-01

Background Three-dimensional (3D) printing is a newly-emerged technology converting a series of two-dimensional images to a touchable 3D model, but no studies have investigated whether or not a 3D printing model is better than a traditional cardiac model for medical education. Methods A 3D printing cardiac model was generated using multi-slice computed tomography datasets. Thirty-four medical students were randomized to either the 3D Printing Group taught with the aid of a 3D printing cardiac model or the Traditional Model Group with a commonly used plastic cardiac model. Questionnaires with 10 medical questions and 3 evaluative questions were filled in by the students. Results A 3D printing cardiac model was successfully generated. Students in the 3D Printing Group were slightly quicker to answer all questions when compared with the Traditional Model Group (224.53 ± 44.13 s vs. 238.71 ± 68.46 s, p = 0.09), but the total score was not significantly different (6.24 ± 1.30 vs. 7.18 ± 1.70, p = 0.12). Neither the students’satisfaction (p = 0.48) nor their understanding of cardiac structures (p = 0.24) was significantly different between two groups. More students in the 3D Printing Group believed that they had understood at least 90% of teaching content (6 vs. 1). Both groups had 12 (70.6%) students who preferred a 3D printing model for medical education. Conclusions A 3D printing model was not significantly superior to a traditional model in teaching cardiac diseases in our pilot randomized controlled study, yet more studies may be conducted to validate the real effect of 3D printing on medical education. PMID:29167621

Empirical study of the dependence of the results of multivariable flexible survival analyses on model selection strategy.

PubMed

Binquet, C; Abrahamowicz, M; Mahboubi, A; Jooste, V; Faivre, J; Bonithon-Kopp, C; Quantin, C

2008-12-30

Flexible survival models, which avoid assumptions about hazards proportionality (PH) or linearity of continuous covariates effects, bring the issues of model selection to a new level of complexity. Each 'candidate covariate' requires inter-dependent decisions regarding (i) its inclusion in the model, and representation of its effects on the log hazard as (ii) either constant over time or time-dependent (TD) and, for continuous covariates, (iii) either loglinear or non-loglinear (NL). Moreover, 'optimal' decisions for one covariate depend on the decisions regarding others. Thus, some efficient model-building strategy is necessary.We carried out an empirical study of the impact of the model selection strategy on the estimates obtained in flexible multivariable survival analyses of prognostic factors for mortality in 273 gastric cancer patients. We used 10 different strategies to select alternative multivariable parametric as well as spline-based models, allowing flexible modeling of non-parametric (TD and/or NL) effects. We employed 5-fold cross-validation to compare the predictive ability of alternative models.All flexible models indicated significant non-linearity and changes over time in the effect of age at diagnosis. Conventional 'parametric' models suggested the lack of period effect, whereas more flexible strategies indicated a significant NL effect. Cross-validation confirmed that flexible models predicted better mortality. The resulting differences in the 'final model' selected by various strategies had also impact on the risk prediction for individual subjects.Overall, our analyses underline (a) the importance of accounting for significant non-parametric effects of covariates and (b) the need for developing accurate model selection strategies for flexible survival analyses. Copyright 2008 John Wiley & Sons, Ltd.

Natural and human-induced terrestrial water storage change: A global analysis using hydrological models and GRACE

NASA Astrophysics Data System (ADS)

Felfelani, Farshid; Wada, Yoshihide; Longuevergne, Laurent; Pokhrel, Yadu N.

2017-10-01

Hydrological models and the data derived from the Gravity Recovery and Climate Experiment (GRACE) satellite mission have been widely used to study the variations in terrestrial water storage (TWS) over large regions. However, both GRACE products and model results suffer from inherent uncertainties, calling for the need to make a combined use of GRACE and models to examine the variations in total TWS and their individual components, especially in relation to natural and human-induced changes in the terrestrial water cycle. In this study, we use the results from two state-of-the-art hydrological models and different GRACE spherical harmonic products to examine the variations in TWS and its individual components, and to attribute the changes to natural and human-induced factors over large global river basins. Analysis of the spatial patterns of the long-term trend in TWS from the two models and GRACE suggests that both models capture the GRACE-measured direction of change, but differ from GRACE as well as each other in terms of the magnitude over different regions. A detailed analysis of the seasonal cycle of TWS variations over 30 river basins shows notable differences not only between models and GRACE but also among different GRACE products and between the two models. Further, it is found that while one model performs well in highly-managed river basins, it fails to reproduce the GRACE-observed signal in snow-dominated regions, and vice versa. The isolation of natural and human-induced changes in TWS in some of the managed basins reveals a consistently declining TWS trend during 2002-2010, however; significant differences are again obvious both between GRACE and models and among different GRACE products and models. Results from the decomposition of the TWS signal into the general trend and seasonality indicate that both models do not adequately capture both the trend and seasonality in the managed or snow-dominated basins implying that the TWS variations from a single model cannot be reliably used for all global regions. It is also found that the uncertainties arising from climate forcing datasets can introduce significant additional uncertainties, making direct comparison of model results and GRACE products even more difficult. Our results highlight the need to further improve the representation of human land-water management and snow processes in large-scale models to enable a reliable use of models and GRACE to study the changes in freshwater systems in all global regions.

Comparison of human radiation exchange models in outdoor areas

NASA Astrophysics Data System (ADS)

Park, Sookuk; Tuller, Stanton E.

2011-10-01

Results from the radiation components of seven different human thermal exchange models/methods are compared. These include the Burt, COMFA, MENEX, OUT_SET* and RayMan models, the six-directional method and the new Park and Tuller model employing projected area factors ( f p) and effective radiation area factors ( f eff) determined from a sample of normal- and over-weight Canadian Caucasian adults. Input data include solar and longwave radiation measured during a clear summer day in southern Ontario. Variations between models came from differences in f p and f eff and different estimates of longwave radiation from the open sky. The ranges between models for absorbed solar, net longwave and net all-wave radiation were 164, 31 and 187 W m-2, respectively. These differentials between models can be significant in total human thermal exchange. Therefore, proper f p and f eff values should be used to make accurate estimation of radiation on the human body surface.

Application of spatial and non-spatial data analysis in determination of the factors that impact municipal solid waste generation rates in Turkey

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

Keser, Saniye; Duzgun, Sebnem; Department of Geodetic and Geographic Information Technologies, Middle East Technical University, 06800 Ankara

Highlights: Black-Right-Pointing-Pointer Spatial autocorrelation exists in municipal solid waste generation rates for different provinces in Turkey. Black-Right-Pointing-Pointer Traditional non-spatial regression models may not provide sufficient information for better solid waste management. Black-Right-Pointing-Pointer Unemployment rate is a global variable that significantly impacts the waste generation rates in Turkey. Black-Right-Pointing-Pointer Significances of global parameters may diminish at local scale for some provinces. Black-Right-Pointing-Pointer GWR model can be used to create clusters of cities for solid waste management. - Abstract: In studies focusing on the factors that impact solid waste generation habits and rates, the potential spatial dependency in solid waste generation datamore » is not considered in relating the waste generation rates to its determinants. In this study, spatial dependency is taken into account in determination of the significant socio-economic and climatic factors that may be of importance for the municipal solid waste (MSW) generation rates in different provinces of Turkey. Simultaneous spatial autoregression (SAR) and geographically weighted regression (GWR) models are used for the spatial data analyses. Similar to ordinary least squares regression (OLSR), regression coefficients are global in SAR model. In other words, the effect of a given independent variable on a dependent variable is valid for the whole country. Unlike OLSR or SAR, GWR reveals the local impact of a given factor (or independent variable) on the waste generation rates of different provinces. Results show that provinces within closer neighborhoods have similar MSW generation rates. On the other hand, this spatial autocorrelation is not very high for the exploratory variables considered in the study. OLSR and SAR models have similar regression coefficients. GWR is useful to indicate the local determinants of MSW generation rates. GWR model can be utilized to plan waste management activities at local scale including waste minimization, collection, treatment, and disposal. At global scale, the MSW generation rates in Turkey are significantly related to unemployment rate and asphalt-paved roads ratio. Yet, significances of these variables may diminish at local scale for some provinces. At local scale, different factors may be important in affecting MSW generation rates.« less

Modeling of heavy-gas effects on airfoil flows

NASA Technical Reports Server (NTRS)

Drela, Mark

1992-01-01

Thermodynamic models were constructed for a calorically imperfect gas and for a non-ideal gas. These were incorporated into a quasi one dimensional flow solver to develop an understanding of the differences in flow behavior between the new models and the perfect gas model. The models were also incorporated into a two dimensional flow solver to investigate their effects on transonic airfoil flows. Specifically, the calculations simulated airfoil testing in a proposed high Reynolds number heavy gas test facility. The results indicate that the non-idealities caused significant differences in the flow field, but that matching of an appropriate non-dimensional parameter led to flows similar to those in air.

Intercomparison of hydrological model structures and calibration approaches in climate scenario impact projections

NASA Astrophysics Data System (ADS)

Vansteenkiste, Thomas; Tavakoli, Mohsen; Ntegeka, Victor; De Smedt, Florimond; Batelaan, Okke; Pereira, Fernando; Willems, Patrick

2014-11-01

The objective of this paper is to investigate the effects of hydrological model structure and calibration on climate change impact results in hydrology. The uncertainty in the hydrological impact results is assessed by the relative change in runoff volumes and peak and low flow extremes from historical and future climate conditions. The effect of the hydrological model structure is examined through the use of five hydrological models with different spatial resolutions and process descriptions. These were applied to a medium sized catchment in Belgium. The models vary from the lumped conceptual NAM, PDM and VHM models over the intermediate detailed and distributed WetSpa model to the fully distributed MIKE SHE model. The latter model accounts for the 3D groundwater processes and interacts bi-directionally with a full hydrodynamic MIKE 11 river model. After careful and manual calibration of these models, accounting for the accuracy of the peak and low flow extremes and runoff subflows, and the changes in these extremes for changing rainfall conditions, the five models respond in a similar way to the climate scenarios over Belgium. Future projections on peak flows are highly uncertain with expected increases as well as decreases depending on the climate scenario. The projections on future low flows are more uniform; low flows decrease (up to 60%) for all models and for all climate scenarios. However, the uncertainties in the impact projections are high, mainly in the dry season. With respect to the model structural uncertainty, the PDM model simulates significantly higher runoff peak flows under future wet scenarios, which is explained by its specific model structure. For the low flow extremes, the MIKE SHE model projects significantly lower low flows in dry scenario conditions in comparison to the other models, probably due to its large difference in process descriptions for the groundwater component, the groundwater-river interactions. The effect of the model calibration was tested by comparing the manual calibration approach with automatic calibrations of the VHM model based on different objective functions. The calibration approach did not significantly alter the model results for peak flow, but the low flow projections were again highly influenced. Model choice as well as calibration strategy hence have a critical impact on low flows, more than on peak flows. These results highlight the high uncertainty in low flow modelling, especially in a climate change context.

Numerical simulation of volume-controlled mechanical ventilated respiratory system with 2 different lungs.

PubMed

Shi, Yan; Zhang, Bolun; Cai, Maolin; Zhang, Xiaohua Douglas

2017-09-01

Mechanical ventilation is a key therapy for patients who cannot breathe adequately by themselves, and dynamics of mechanical ventilation system is of great significance for life support of patients. Recently, models of mechanical ventilated respiratory system with 1 lung are used to simulate the respiratory system of patients. However, humans have 2 lungs. When the respiratory characteristics of 2 lungs are different, a single-lung model cannot reflect real respiratory system. In this paper, to illustrate dynamic characteristics of mechanical ventilated respiratory system with 2 different lungs, we propose a mathematical model of mechanical ventilated respiratory system with 2 different lungs and conduct experiments to verify the model. Furthermore, we study the dynamics of mechanical ventilated respiratory system with 2 different lungs. This research study can be used for improving the efficiency and safety of volume-controlled mechanical ventilation system. Copyright © 2016 John Wiley & Sons, Ltd.

Assessment of Listeria monocytogenes virulence in the Galleria mellonella insect larvae model.

PubMed

Rakic Martinez, Mira; Wiedmann, Martin; Ferguson, Martine; Datta, Atin R

2017-01-01

Several animal models have been used to understand the molecular basis of the pathogenicity, infectious dose and strain to strain variation of Listeria monocytogenes. The greater wax worm Galleria mellonella, as an alternative model, provides some useful advantages not available with other models and has already been described as suitable for the virulence assessment of various pathogens including L. monocytogenes. The objectives of this study are: 1) confirming the usefulness of this model with a wide panel of Listeria spp. including non-pathogenic L. innocua, L. seeligeri, L. welshimeri and animal pathogen L. ivanovii; 2) assessment of virulence of several isogenic in-frame deletion mutants in virulence and stress related genes of L. monocytogenes and 3) virulence assessment of paired food and clinical isolates of L. monocytogenes from 14 major listeriosis outbreaks occurred worldwide between 1980 and 2015. Larvae injected with different concentrations of Listeria were incubated at 37°C and monitored over seven days for time needed to kill 50% of larvae (LT50) and to determine change of bacterial population in G. mellonella, 2 and 24 hours post-inoculation. Non-pathogenic members of Listeria and L. ivanovii showed significantly (P < 0.05) higher LT50 (lower virulence) than the wild type L. monocytogenes strains. Isogenic mutants of L. monocytogenes with the deletions in prfA, plcA, hly, actA and virR genes, also showed significantly (P < 0.05) higher LT50 than the wild type strain at the inoculum of 106CFU/larva. Food isolates had significantly (P < 0.05) lower virulence than the paired clinical isolates, at all three inoculum concentrations. L. monocytogenes strains related to non-invasive (gastroenteritis) outbreaks of listeriosis showed significantly (P < 0.05) lower virulence than isolates of the same serotype obtained from outbreaks with invasive symptoms. The difference, however, was dose and strain- dependent. No significant differences in virulence were observed among the serotype tested in this study.

Assessment of Listeria monocytogenes virulence in the Galleria mellonella insect larvae model

PubMed Central

Rakic Martinez, Mira; Ferguson, Martine; Datta, Atin R.

2017-01-01

Several animal models have been used to understand the molecular basis of the pathogenicity, infectious dose and strain to strain variation of Listeria monocytogenes. The greater wax worm Galleria mellonella, as an alternative model, provides some useful advantages not available with other models and has already been described as suitable for the virulence assessment of various pathogens including L. monocytogenes. The objectives of this study are: 1) confirming the usefulness of this model with a wide panel of Listeria spp. including non-pathogenic L. innocua, L. seeligeri, L. welshimeri and animal pathogen L. ivanovii; 2) assessment of virulence of several isogenic in-frame deletion mutants in virulence and stress related genes of L. monocytogenes and 3) virulence assessment of paired food and clinical isolates of L. monocytogenes from 14 major listeriosis outbreaks occurred worldwide between 1980 and 2015. Larvae injected with different concentrations of Listeria were incubated at 37°C and monitored over seven days for time needed to kill 50% of larvae (LT50) and to determine change of bacterial population in G. mellonella, 2 and 24 hours post-inoculation. Non-pathogenic members of Listeria and L. ivanovii showed significantly (P < 0.05) higher LT50 (lower virulence) than the wild type L. monocytogenes strains. Isogenic mutants of L. monocytogenes with the deletions in prfA, plcA, hly, actA and virR genes, also showed significantly (P < 0.05) higher LT50 than the wild type strain at the inoculum of 106CFU/larva. Food isolates had significantly (P < 0.05) lower virulence than the paired clinical isolates, at all three inoculum concentrations. L. monocytogenes strains related to non-invasive (gastroenteritis) outbreaks of listeriosis showed significantly (P < 0.05) lower virulence than isolates of the same serotype obtained from outbreaks with invasive symptoms. The difference, however, was dose and strain- dependent. No significant differences in virulence were observed among the serotype tested in this study. PMID:28898264

Modelling the fate of organic micropollutants in stormwater ponds.

PubMed

Vezzaro, Luca; Eriksson, Eva; Ledin, Anna; Mikkelsen, Peter S

2011-06-01

Urban water managers need to estimate the potential removal of organic micropollutants (MP) in stormwater treatment systems to support MP pollution control strategies. This study documents how the potential removal of organic MP in stormwater treatment systems can be quantified by using multimedia models. The fate of four different MP in a stormwater retention pond was simulated by applying two steady-state multimedia fate models (EPI Suite and SimpleBox) commonly applied in chemical risk assessment and a dynamic multimedia fate model (Stormwater Treatment Unit Model for Micro Pollutants--STUMP). The four simulated organic stormwater MP (iodopropynyl butylcarbamate--IPBC, benzene, glyphosate and pyrene) were selected according to their different urban sources and environmental fate. This ensures that the results can be extended to other relevant stormwater pollutants. All three models use substance inherent properties to calculate MP fate but differ in their ability to represent the small physical scale and high temporal variability of stormwater treatment systems. Therefore the three models generate different results. A Global Sensitivity Analysis (GSA) highlighted that settling/resuspension of particulate matter was the most sensitive process for the dynamic model. The uncertainty of the estimated MP fluxes can be reduced by calibrating the dynamic model against total suspended solids data. This reduction in uncertainty was more significant for the substances with strong tendency to sorb, i.e. glyphosate and pyrene and less significant for substances with a smaller tendency to sorb, i.e. IPBC and benzene. The results provide support to the elaboration of MP pollution control strategies by limiting the need for extensive and complex monitoring campaigns targeting the wide range of specific organic MP found in stormwater runoff. Copyright © 2011 Elsevier B.V. All rights reserved.

Sources of uncertainty in hydrological climate impact assessment: a cross-scale study

NASA Astrophysics Data System (ADS)

Hattermann, F. F.; Vetter, T.; Breuer, L.; Su, Buda; Daggupati, P.; Donnelly, C.; Fekete, B.; Flörke, F.; Gosling, S. N.; Hoffmann, P.; Liersch, S.; Masaki, Y.; Motovilov, Y.; Müller, C.; Samaniego, L.; Stacke, T.; Wada, Y.; Yang, T.; Krysnaova, V.

2018-01-01

Climate change impacts on water availability and hydrological extremes are major concerns as regards the Sustainable Development Goals. Impacts on hydrology are normally investigated as part of a modelling chain, in which climate projections from multiple climate models are used as inputs to multiple impact models, under different greenhouse gas emissions scenarios, which result in different amounts of global temperature rise. While the goal is generally to investigate the relevance of changes in climate for the water cycle, water resources or hydrological extremes, it is often the case that variations in other components of the model chain obscure the effect of climate scenario variation. This is particularly important when assessing the impacts of relatively lower magnitudes of global warming, such as those associated with the aspirational goals of the Paris Agreement. In our study, we use ANOVA (analyses of variance) to allocate and quantify the main sources of uncertainty in the hydrological impact modelling chain. In turn we determine the statistical significance of different sources of uncertainty. We achieve this by using a set of five climate models and up to 13 hydrological models, for nine large scale river basins across the globe, under four emissions scenarios. The impact variable we consider in our analysis is daily river discharge. We analyze overall water availability and flow regime, including seasonality, high flows and low flows. Scaling effects are investigated by separately looking at discharge generated by global and regional hydrological models respectively. Finally, we compare our results with other recently published studies. We find that small differences in global temperature rise associated with some emissions scenarios have mostly significant impacts on river discharge—however, climate model related uncertainty is so large that it obscures the sensitivity of the hydrological system.

Determining the importance of model calibration for forecasting absolute/relative changes in streamflow from LULC and climate changes

USGS Publications Warehouse

Niraula, Rewati; Meixner, Thomas; Norman, Laura M.

2015-01-01

Land use/land cover (LULC) and climate changes are important drivers of change in streamflow. Assessing the impact of LULC and climate changes on streamflow is typically done with a calibrated and validated watershed model. However, there is a debate on the degree of calibration required. The objective of this study was to quantify the variation in estimated relative and absolute changes in streamflow associated with LULC and climate changes with different calibration approaches. The Soil and Water Assessment Tool (SWAT) was applied in an uncalibrated (UC), single outlet calibrated (OC), and spatially-calibrated (SC) mode to compare the relative and absolute changes in streamflow at 14 gaging stations within the Santa Cruz River Watershed in southern Arizona, USA. For this purpose, the effect of 3 LULC, 3 precipitation (P), and 3 temperature (T) scenarios were tested individually. For the validation period, Percent Bias (PBIAS) values were >100% with the UC model for all gages, the values were between 0% and 100% with the OC model and within 20% with the SC model. Changes in streamflow predicted with the UC and OC models were compared with those of the SC model. This approach implicitly assumes that the SC model is “ideal”. Results indicated that the magnitude of both absolute and relative changes in streamflow due to LULC predicted with the UC and OC results were different than those of the SC model. The magnitude of absolute changes predicted with the UC and SC models due to climate change (both P and T) were also significantly different, but were not different for OC and SC models. Results clearly indicated that relative changes due to climate change predicted with the UC and OC were not significantly different than that predicted with the SC models. This result suggests that it is important to calibrate the model spatially to analyze the effect of LULC change but not as important for analyzing the relative change in streamflow due to climate change. This study also indicated that model calibration in not necessary to determine the direction of change in streamflow due to LULC and climate change.

EEG spectral analysis in primary insomnia: NREM period effects and sex differences.

PubMed

Buysse, Daniel J; Germain, Anne; Hall, Martica L; Moul, Douglas E; Nofzinger, Eric A; Begley, Amy; Ehlers, Cindy L; Thompson, Wesley; Kupfer, David J

2008-12-01

To compare NREM EEG power in primary insomnia (PI) and good sleeper controls (GSC), examining both sex and NREM period effects; to examine relationships between EEG power, clinical characteristics, and self-reports of sleep. Overnight polysomnographic study. Sleep laboratory. PI (n=48; 29 women) and GSC (n=25; 15 women). None. EEG power from 1-50 Hz was computed for artifact-free sleep epochs across four NREM periods. Repeated measures mixed effect models contrasted differences between groups, EEG frequency bands, and NREM periods. EEG power-frequency curves were modeled using regressions with fixed knot splines. Mixed models showed no significant group (PI vs. GSC) differences; marginal sex differences (delta and theta bands); significant differences across NREM periods; and group*sex and group*NREM period interactions, particularly in beta and gamma bands. Modeled power-frequency curves showed no group difference in whole-night NREM, but PI had higher power than GSC from 18-40 Hz in the first NREM period. Among women, PI had higher 16 to 44-Hz power than GSC in the first 3 NREM periods, and higher 3 to 5-Hz power across all NREM periods. PI and GSC men showed no consistent differences in EEG power. High-frequency EEG power was not related to clinical or subjective sleep ratings in PI. Women with PI, but not men, showed increased high-frequency and low-frequency EEG activity during NREM sleep compared to GSC, particularly in early NREM periods. Sex and NREM period may moderate quantitative EEG differences between PI and GSC.

Elastic properties of external cortical bone in the craniofacial skeleton of the rhesus monkey.

PubMed

Wang, Qian; Dechow, Paul C

2006-11-01

Knowledge of elastic properties and of their variation in the cortical bone of the craniofacial skeleton is indispensable for creating accurate finite-element models to explore the biomechanics and adaptation of the skull in primates. In this study, we measured elastic properties of the external cortex of the rhesus monkey craniofacial skeleton, using an ultrasonic technique. Twenty-eight cylindrical cortical specimens were removed from each of six craniofacial skeletons of adult Macaca mulatta. Thickness, density, and a set of longitudinal and transverse ultrasonic velocities were measured on each specimen to allow calculation of the elastic properties in three dimensions, according to equations derived from Newton's second law and Hooke's law. The axes of maximum stiffness were determined by fitting longitudinal velocities measured along the perimeter of each cortical specimen to a sinusoidal function. Results showed significant differences in elastic properties between different functional areas of the rhesus cranium, and that many sites have a consistent orientation of maximum stiffness among specimens. Overall, the cortical bones of the rhesus monkey skull can be modeled as orthotropic in many regions, and as transversely isotropic in some regions, e.g., the supraorbital region. There are differences from human crania, suggesting that structural differences in skeletal form relate to differences in cortical material properties across species. These differences also suggest that we require more comparative data on elastic properties in primate craniofacial skeletons to explore effectively the functional significance of these differences, especially when these differences are elucidated through modeling approaches, such as finite-element modeling. (c) 2006 Wiley-Liss, Inc.

Scopolamine-induced greater alterations in neurochemical profile and increased oxidative stress demonstrated a better model of dementia: A comparative study.

PubMed

Haider, Saida; Tabassum, Saiqa; Perveen, Tahira

2016-10-01

Cognitive decline is found to be a common feature of various neurological disorders like Alzheimer's disease (AD). In order to recapitulate AD associated cognitive deficits and to plan therapeutic strategies researchers have developed various preclinical dementia models to recapitulate different aspects of cognitive domains affected in AD brain. So, the present study was aimed to compare alterations in previously reported dementia models i.e. pharmacological (Scopolamine-induced and corticosterone-induced), Environmental (Aluminium-induced and noise-stress) and physiological (natural aging) models in rats in a single experimental study across three cognitive domains spatial, recognition, and associative memory and associated alterations in their oxidative status and neurochemical profile to select appropriate dementia model. All groups received their respective treatments for 14days after which behavioural analysis was performed including Open Field test to assess ambulatory activity, Novel Object Recognition test, Morris Water Maze test and Passive Avoidance test for the assessment of recognition, spatial and associative memory. After monitoring the behavioural activities, rats were decapitated and their brains and hippocampus samples were collected for analysis of oxidative status and neurochemical profile. Results showed significant decline in different aspects of memory function in all dementia models which was more significant in scopolamine-injected rats. A significant decline in levels of monoamines and acetylcholine was also observed. In addition, significant alterations were also seen in oxidative profile indicating that cognitive decline could be associated with increased oxidative stress. Therefore, present findings highlight that for planning therapeutic strategies against cognitive dysfunctions, scopolamine-induced dementia model is the most appropriate dementia model to reveal AD-related cognitive impairment profile. Copyright © 2016 Elsevier Inc. All rights reserved.

Comparison of three types of stress urinary incontinence rat models: electrocauterization, pudendal denervation, and vaginal distension.

PubMed

Hong, Sung-Hoo; Piao, Shuyu; Kim, In Gul; Lee, Ji Young; Cho, Hyuk Jin; Kim, Sae Woong; Hwang, Tae-Kon; Lee, Ji Youl

2013-02-01

To investigate the differences in the histopathologic and functional characteristics of 3 rat models of stress urinary incontinence. A total of 24 female, 10-week-old, Sprague-Dawley rats were randomly divided into 4 groups: normal, electrocauterization, pudendal denervation, and vaginal distension. At 2 weeks after surgery, the leak point pressure was measured to detect urinary leakage. Urethral tissue samples were collected for histological examination. The smooth muscle content in the electrocauterization group was significantly decreased compared with that in all other groups, indicating that electrocauterization caused the most severe injury. A blood vessel marker, von Willebrand factor, was co-stained with α-smooth muscle actin to detect the blood vessel distribution. No significant differences were seen in von Willebrand factor expression among the 4 groups, other than in the electrocauterization group, in which we could hardly observe blood vessel expression. Protein gene product 9.5 staining was used to detect nerve fibers and cells. Protein gene product 9.5 expression was significantly lower in all the treatment groups compared with that in the normal group (P <.05), in particular, in the electrocauterization and pudendal denervation groups (P <.01). The leak point pressure was significantly lower in the electrocauterization (P <.01), pudendal denervation (P <.01), and vaginal distension (P <.05) groups than in the normal group. The vaginal distension model should mainly be used as the myogenic damage stress urinary incontinence animal model; the pudendal denervation model mainly as the neurogenic damage stress urinary incontinence animal model; and the electrocauterization model as the vasculogenic, neurogenic, and myogenic damage animal model. Copyright © 2013. Published by Elsevier Inc.

Dynamic FDG-PET Imaging to Differentiate Malignancies from Inflammation in Subcutaneous and In Situ Mouse Model for Non-Small Cell Lung Carcinoma (NSCLC).

PubMed

Yang, Zhen; Zan, Yunlong; Zheng, Xiujuan; Hai, Wangxi; Chen, Kewei; Huang, Qiu; Xu, Yuhong; Peng, Jinliang

2015-01-01

[18F]fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) has been widely used in oncologic procedures such as tumor diagnosis and staging. However, false-positive rates have been high, unacceptable and mainly caused by inflammatory lesions. Misinterpretations take place especially when non-subcutaneous inflammations appear at the tumor site, for instance in the lung. The aim of the current study is to evaluate the use of dynamic PET imaging procedure to differentiate in situ and subcutaneous non-small cell lung carcinoma (NSCLC) from inflammation, and estimate the kinetics of inflammations in various locations. Dynamic FDG-PET was performed on 33 female mice inoculated with tumor and/or inflammation subcutaneously or inside the lung. Standardized Uptake Values (SUVs) from static imaging (SUVmax) as well as values of influx rate constant (Ki) of compartmental modeling from dynamic imaging were obtained. Static and kinetic data from different lesions (tumor and inflammations) or different locations (subcutaneous, in situ and spontaneous group) were compared. Values of SUVmax showed significant difference in subcutaneous tumor and inflammation (p<0.01), and in inflammations from different locations (p<0.005). However, SUVmax showed no statistical difference between in situ tumor and inflammation (p = 1.0) and among tumors from different locations (subcutaneous and in situ, p = 0.91). Values of Ki calculated from compartmental modeling showed significant difference between tumor and inflammation both subcutaneously (p<0.005) and orthotopically (p<0.01). Ki showed also location specific values for inflammations (subcutaneous, in situ and spontaneous, p<0.015). However, Ki of tumors from different locations (subcutaneous and in situ) showed no significant difference (p = 0.46). In contrast to static PET based SUVmax, both subcutaneous and in situ inflammations and malignancies can be differentiated via dynamic FDG-PET based Ki. Moreover, Values of influx rate constant Ki from compartmental modeling can offer an assessment for inflammations at different locations of the body, which also implies further validation is necessary before the replacement of in situ inflammation with its subcutaneous counterpart in animal experiments.

[The expression and significance of chemokines eotaxin and RANTES in the rat model of allergic rhinitis].

PubMed

Tian, Cuiling; Lei, Xiaoping; Shui, Minhong; Zhang, Yanhong; Jia, Qianwei; Tu, Jing; Lian, Gang; Tang, Siquan

2014-07-01

To explore the expression and significance of Eotaxin and RANTES in the rat model of allergic rhinitis (AR). 20 female SD rats in 6-7 weeks were randomly divided into control group and AR group (n = 10, respectively). AR rat model was made with ovalbumin stimulation. To detect pathological changes in mucosa and chemokine Eotaxin, RANTES in their nasal and lung tissues after execution. Compared with the control group, Lung EOS cell counted higher in AR group and the difference was significant (P < 0.01); the AR rats nasal mucosa and lung tissue of Eotaxin, RANTES expression was significantly increased (P < 0.01). There exist high expression of Eotaxin, RANTES, infiltration of eosinophils in nasal and lung tissue of model rats with allergic rhinitis, inferring that the upper and lower respiratory tract inflammatory response has obvious consistency.

Modelling and simulation of thermal behaviour of vanadium redox flow battery

NASA Astrophysics Data System (ADS)

Yan, Yitao; Li, Yifeng; Skyllas-Kazacos, Maria; Bao, Jie

2016-08-01

This paper extends previous thermal models of the vanadium redox flow battery to predict temperature profiles within multi-cell stacks. This involves modelling the thermal characteristics of the stack as a whole to modelling each individual cell. The study investigates the thermal behaviour for two different scenarios: during standby periods when the pumps are turned off, and in a residential power arbitrage scenario for two types of membranes. It was found that the temperature gradient across the cells is most significant during the standby case, with the simulation results showing completely different thermal behaviours between the two systems.

[Study on relationship of dose-effect and time-effect of APA microencapsulated bovine chromaffin cells on pain treatment].

PubMed

Hui, Jianfeng; Li, Tao; Du, Zhi; Song, Jichang

2011-12-01

This study was to investigate the relationship of dose-effect and time-effect of Alginate-Polylysine-Alginate (APA) microencapsulated bovine chromaffin cells on the treatment of pain model rats. Using a rat model of painful peripheral neuropathy, the antinociceptive effects of APA microencapsulated bovine cells transplanted into the subarachnoid space was evaluated by cold allodynia test and hot hyperalgesia test. Compared with control group, the withdrawal difference with cell number 50 thousands groups, 100 thousands groups and 200 thousands groups was reduced (P < 0.05), and the difference decreased with the cells increases, indicating a significant analgesic effect. There was no significant difference between 400 thousands groups and 200 thousands groups. This analgesic effect maintained longer than 12 weeks. There was a positive correlation between the analgesic effect and the quantity of APA microencapsulated bovine chromaffin cells which were transplanted to treat pain model rats, and the effective antinociception remained longer than 12 weeks.

Comparison of Actual Surgical Outcomes and 3D Surgical Simulations

PubMed Central

Tucker, Scott; Cevidanes, Lucia; Styner, Martin; Kim, Hyungmin; Reyes, Mauricio; Proffit, William; Turvey, Timothy

2009-01-01

Purpose The advent of imaging software programs have proved to be useful for diagnosis, treatment planning, and outcome measurement, but precision of 3D surgical simulation still needs to be tested. This study was conducted to determine if the virtual surgery performed on 3D models constructed from Cone-beam CT (CBCT) can correctly simulate the actual surgical outcome and to validate the ability of this emerging technology to recreate the orthognathic surgery hard tissue movements in 3 translational and 3 rotational planes of space. Methods Construction of pre- and post-surgery 3D models from CBCTs of 14 patients who had combined maxillary advancement and mandibular setback surgery and 6 patients who had one-piece maxillary advancement surgery was performed. The post-surgery and virtually simulated surgery 3D models were registered at the cranial base to quantify differences between simulated and actual surgery models. Hotelling T-test were used to assess the differences between simulated and actual surgical outcomes. Results For all anatomic regions of interest, there was no statistically significant difference between the simulated and the actual surgical models. The right lateral ramus was the only region that showed a statistically significant, but small difference when comparing two- and one-jaw surgeries. Conclusions Virtual surgical methods were reliably reproduced, oral surgery residents could benefit from virtual surgical training, and computer simulation has the potential to increase predictability in the operating room. PMID:20591553

On the importance of appropriate precipitation gauge catch correction for hydrological modelling at mid to high latitudes

NASA Astrophysics Data System (ADS)

Stisen, S.; Højberg, A. L.; Troldborg, L.; Refsgaard, J. C.; Christensen, B. S. B.; Olsen, M.; Henriksen, H. J.

2012-11-01

Precipitation gauge catch correction is often given very little attention in hydrological modelling compared to model parameter calibration. This is critical because significant precipitation biases often make the calibration exercise pointless, especially when supposedly physically-based models are in play. This study addresses the general importance of appropriate precipitation catch correction through a detailed modelling exercise. An existing precipitation gauge catch correction method addressing solid and liquid precipitation is applied, both as national mean monthly correction factors based on a historic 30 yr record and as gridded daily correction factors based on local daily observations of wind speed and temperature. The two methods, named the historic mean monthly (HMM) and the time-space variable (TSV) correction, resulted in different winter precipitation rates for the period 1990-2010. The resulting precipitation datasets were evaluated through the comprehensive Danish National Water Resources model (DK-Model), revealing major differences in both model performance and optimised model parameter sets. Simulated stream discharge is improved significantly when introducing the TSV correction, whereas the simulated hydraulic heads and multi-annual water balances performed similarly due to recalibration adjusting model parameters to compensate for input biases. The resulting optimised model parameters are much more physically plausible for the model based on the TSV correction of precipitation. A proxy-basin test where calibrated DK-Model parameters were transferred to another region without site specific calibration showed better performance for parameter values based on the TSV correction. Similarly, the performances of the TSV correction method were superior when considering two single years with a much dryer and a much wetter winter, respectively, as compared to the winters in the calibration period (differential split-sample tests). We conclude that TSV precipitation correction should be carried out for studies requiring a sound dynamic description of hydrological processes, and it is of particular importance when using hydrological models to make predictions for future climates when the snow/rain composition will differ from the past climate. This conclusion is expected to be applicable for mid to high latitudes, especially in coastal climates where winter precipitation types (solid/liquid) fluctuate significantly, causing climatological mean correction factors to be inadequate.

Influence of visual observational conditions on tongue motor learning.

PubMed

Kothari, Mohit; Liu, Xuemei; Baad-Hansen, Lene; Kumar, Abhishek; Bin, Guo; Svensson, Peter

2016-12-01

The aim of this study was to investigate the impact of visual observational conditions on performance during a standardized tongue-protrusion training (TPT) task and to evaluate subject-based reports of helpfulness, disturbance, pain, and fatigue, due to the observational conditions on 0-10 numerical rating scales. Forty-eight healthy participants performed a 1-h standard TPT task. Participants were randomly assigned to one of the following three groups with different observational conditions: group 1, model observation (participants watched a prerecorded video showing standard TPT before optimal TPT being performed); group 2, self-observation (participants watched live video feedback of their own TPT performance); and group 3, control group (participants performed the TPT with no conditioning). There was no overall difference between groups but TPT performance increased over time. A significant group×time interaction indicated that the self-observation group performed significantly better than the model-observation group in the last 20 min of TPT. The subject-based reports of video helpfulness showed that the model-observation group rated the prerecorded video as more helpful for TPT performance compared with the other groups but there was no significant difference between groups regarding the level of disturbance, pain, or fatigue. Self-observation of tongue-training facilitated behavioral aspects of tongue motor learning compared with model observation but not compared with control. © 2016 Eur J Oral Sci.

Development of an animal model of fibrous cholangitis in pigs.

PubMed

Lainakis, Nektarios G; Papalois, Apostolos; Agrogiannis, Georgios; Antonopoulos, Constantine N; Michail, Panagiotis; Bastounis, Elias; Patsouris, Efstathios; Felekouras, Evangelos

2014-04-01

The aim of this study was to develop a model of fibrous cholangitis in the offspring of gravid domestic pigs through the administration of 1,4-phenylene diisothiocyanate (DITC). Six young domestic pigs and two gravid pigs with their offspring (21 pigs) were used as experimental models and six wild-type animals were used as controls. All pigs were divided into five main groups and five subgroups, according to their developmental stage and time of exposure to DITC. The following histopathological characteristics were quantitatively evaluated on a scale of 0-5: ductal proliferation, periportal fibrosis, inflammatory infiltration, periductal fibrosis and edema, intraluminal fibrosis, duct wall thickening, epithelial apoptosis, and arterial hyperplasia/hypertrophy. Statistically significant differences were observed for most of the histopathological markers between the group of pigs' offspring that received DITC at early gestation and their control group. Moreover, the group of animals that were exposed to the agent at early gestation exhibited significant differences for all histopathological characteristics compared to the animals that were exposed at late gestation. On the other hand, no statistically significant differences were observed between the group of animals that received the agent at late gestation and their healthy controls. Administration of DITC to domestic pigs in early pregnancy may induce histopathological patterns of fibrous cholangitis to their offspring imitating biliary atresia. This model may provide insight to the pathogenesis of the obstructive cholangitis in pigs.

Interactions of oversulfated chondroitin sulfate (OSCS) from different sources with unfractionated heparin.

PubMed

Gray, Angel; Litinas, Evangelos; Jeske, Walter; Fareed, Jawed; Hoppensteadt, Debra

2012-01-01

In 2008, oversulfated chondroitin sulfate (OSCS) was identified as the main contaminant in recalled heparin. Oversulfated chondroitin sulfate can be prepared from bovine (B), porcine (P), shark (Sh), or skate (S) origin and may produce changes in the antithrombotic, bleeding, and hemodynamic profile of heparins. This study examines the interactions of various OSCSs on heparin in animal models of thrombosis and bleeding, as well as on the anticoagulant and antiprotease effects in in vitro assays. Mixtures of 70% unfractionated heparin (UFH) with 30% OSCS from different sources were tested. In the in vitro activated partial thromboplastin time (aPTT) assay, all contaminant mixtures showed a decrease in clotting times. In addition, a significant increase in bleeding time compared to the control (UFH/saline) was observed. In the thrombosis model, no significant differences were observed. The OSCSs significantly increased anti-Xa activity in ex vivo blood samples. These results indicate that various sources of OSCS affect the hemostatic properties of heparin.

Effect of Fordyce Happiness Model on depression, stress, anxiety, and fatigue in patients with multiple sclerosis.

PubMed

Khayeri, Fereydoon; Rabiei, Leili; Shamsalinia, Abbas; Masoudi, Reza

2016-11-01

This study was conducted to investigate the effect of Fordyce Happiness Model (FHM) on depression, stress, anxiety, and fatigue in MS patients. In this clinical trial, 140 MS patients assigned to experimental and control groups. Depression, anxiety, stress, and fatigue were measured by Depression Anxiety Stress Scale-21 and Piper Standard Scale before and immediately and three months after the implementation of FHM. The data were analyzed by SPSS 18. Independent t-test indicated that total scores of stress, depression, and fatigue of the two groups were not significantly different before the intervention but were significantly different after the intervention (P˂0.05). Moreover, anxiety scores of the two were not significantly different after the intervention (P˃0.05). FHM can assist MS patients to manage their disease and associated problems in life. Besides that, since FHM is efficient and costless, it can be incorporated into the health interventions for MS patients. Copyright © 2016 Elsevier Ltd. All rights reserved.

Classification of commercial wines from the Canary Islands (Spain) by chemometric techniques using metallic contents.

PubMed

Frías, Sergio; Conde, José E; Rodríguez-Bencomo, Juan J; García-Montelongo, Francisco; Pérez-Trujillo, Juan P

2003-02-06

Eleven elements, K, Na, Ca, Mg, Fe, Cu, Zn, Mn, Sr, Li and Rb, were determined in dry and sweet wines bearing the denominations of origin of El Hierro, La Palma and Lanzarote islands (Canary Islands, Spain). Analyses were performed by flame atomic absorption spectrophotometry, with the exceptions of lithium and rubidium for which flame atomic emission spectrophotometry was used. Sweet wines from La Palma were elaborated as naturally sweet with over-ripe grapes and significant differences were found in all the analysed elements with the exceptions of sodium, iron and rubidium with regard to dry wines from the same island. Contrarily, sweet wines from Lanzarote elaborated with grapes in a similar ripening state to dry wines did not present significant differences between them with the exception of strontium, the content of which was greater in dry wines. Among the three islands, significant differences in mean content were found with the exceptions of iron and copper. Cluster analysis and principal component analysis show differences in wines according to the island of origin and the ripening state of the grapes. Linear discriminant analysis using rubidium, sodium, manganese and strontium, the four most discriminant elements, gave 100% recognition ability and 95.6% prediction ability. The sensitivity and specificity obtained using soft independent modelling of class analogy (SIMCA) as a modelling multivariate technique were both 100% for El Hierro and Lanzarote, and 100 and 95%, respectively, for La Palma. The modelling and discriminant capacities of the different metals were also studied.

The effect of inquiry-flipped classroom model toward students' achievement on chemical reaction rate

NASA Astrophysics Data System (ADS)

Paristiowati, Maria; Fitriani, Ella; Aldi, Nurul Hanifah

2017-08-01

The aim of this research is to find out the effect of Inquiry-Flipped Classroom Models toward Students' Achievement on Chemical Reaction Rate topic. This study was conducted at SMA Negeri 3 Tangerang in Eleventh Graders. The Quasi Experimental Method with Non-equivalent Control Group design was implemented in this study. 72 students as the sample was selected by purposive sampling. Students in experimental group were learned through inquiry-flipped classroom model. Meanwhile, in control group, students were learned through guided inquiry learning model. Based on the data analysis, it can be seen that there is significant difference in the result of the average achievement of the students. The average achievement of the students in inquiry-flipped classroom model was 83,44 and the average achievement of the students in guided inquiry learning model was 74,06. It can be concluded that the students' achievement with inquiry-flipped classroom better than guided inquiry. The difference of students' achievement were significant through t-test which is tobs 3.056 > ttable 1.994 (α = 0.005).

Observing the clustering properties of galaxy clusters in dynamical dark-energy cosmologies

NASA Astrophysics Data System (ADS)

Fedeli, C.; Moscardini, L.; Bartelmann, M.

2009-06-01

We study the clustering properties of galaxy clusters expected to be observed by various forthcoming surveys both in the X-ray and sub-mm regimes by the thermal Sunyaev-Zel'dovich effect. Several different background cosmological models are assumed, including the concordance ΛCDM and various cosmologies with dynamical evolution of the dark energy. Particular attention is paid to models with a significant contribution of dark energy at early times which affects the process of structure formation. Past light cone and selection effects in cluster catalogs are carefully modeled by realistic scaling relations between cluster mass and observables and by properly taking into account the selection functions of the different instruments. The results show that early dark-energy models are expected to produce significantly lower values of effective bias and both spatial and angular correlation amplitudes with respect to the standard ΛCDM model. Among the cluster catalogs studied in this work, it turns out that those based on eRosita, Planck, and South Pole Telescope observations are the most promising for distinguishing between various dark-energy models.

Improving the accuracy of macromolecular structure refinement at 7 Å resolution.

PubMed

Brunger, Axel T; Adams, Paul D; Fromme, Petra; Fromme, Raimund; Levitt, Michael; Schröder, Gunnar F

2012-06-06

In X-ray crystallography, molecular replacement and subsequent refinement is challenging at low resolution. We compared refinement methods using synchrotron diffraction data of photosystem I at 7.4 Å resolution, starting from different initial models with increasing deviations from the known high-resolution structure. Standard refinement spoiled the initial models, moving them further away from the true structure and leading to high R(free)-values. In contrast, DEN refinement improved even the most distant starting model as judged by R(free), atomic root-mean-square differences to the true structure, significance of features not included in the initial model, and connectivity of electron density. The best protocol was DEN refinement with initial segmented rigid-body refinement. For the most distant initial model, the fraction of atoms within 2 Å of the true structure improved from 24% to 60%. We also found a significant correlation between R(free) values and the accuracy of the model, suggesting that R(free) is useful even at low resolution. Copyright © 2012 Elsevier Ltd. All rights reserved.

Comparison of body composition between fashion models and women in general.

PubMed

Park, Sunhee

2017-12-31

The present study compared the physical characteristics and body composition of professional fashion models and women in general, utilizing the skinfold test. The research sample consisted of 90 professional fashion models presently active in Korea and 100 females in the general population, all selected through convenience sampling. Measurement was done following standardized methods and procedures set by the International Society for the Advancement of Kinanthropometry. Body density (mg/ mm) and body fat (%) were measured at the biceps, triceps, subscapular, and suprailiac areas. The results showed that the biceps, triceps, subscapular, and suprailiac areas of professional fashion models were significantly thinner than those of women in general (p<.001), and that their waist size was also significantly smaller (p<.001). However, hip circumference showed no significant difference. Body mass index, waist-to-hip ratio, and body fat (%) in professional fashion models were significantly lower than those in women in general (p<.001), while the body density in professional fashion models was significantly greater (p<.001). Body density in professional fashion models is higher, due to taller stature, than in women in general. Moreover, there is an effort on the part of fashion models to lose weight in order to maintain a thin body and a low weight for occupational reasons. ©2017 The Korean Society for Exercise Nutrition

Comparison of body composition between fashion models and women in general

PubMed Central

Park, Sunhee

2017-01-01

[Purpose] The present study compared the physical characteristics and body composition of professional fashion models and women in general, utilizing the skinfold test. [Methods] The research sample consisted of 90 professional fashion models presently active in Korea and 100 females in the general population, all selected through convenience sampling. Measurement was done following standardized methods and procedures set by the International Society for the Advancement of Kinanthropometry. Body density (mg/ mm) and body fat (%) were measured at the biceps, triceps, subscapular, and suprailiac areas. [Results] The results showed that the biceps, triceps, subscapular, and suprailiac areas of professional fashion models were significantly thinner than those of women in general (p<.001), and that their waist size was also significantly smaller (p<.001). However, hip circumference showed no significant difference. Body mass index, waist-to-hip ratio, and body fat (%) in professional fashion models were significantly lower than those in women in general (p<.001), while the body density in professional fashion models was significantly greater (p<.001). [Conclusion] Body density in professional fashion models is higher, due to taller stature, than in women in general. Moreover, there is an effort on the part of fashion models to lose weight in order to maintain a thin body and a low weight for occupational reasons. PMID:29370670

Experimental and model-based analysis of differences in perception of cutaneous electrical stimulation across the sole of the foot.

PubMed

Frahm, Ken Steffen; Mørch, Carsten Dahl; Grill, Warren M; Andersen, Ole Kæseler

2013-09-01

During electrocutaneous stimulations, variation in skin properties across locations can lead to differences in neural activation. However, little focus has been given to the effect of different skin thicknesses on neural activation. Electrical stimulation was applied to six sites across the sole of the foot. The intensities used were two and four times perception threshold. The subjects (n = 8) rated the perception quality and intensity using the McGill Pain Questionnaire and a visual analog scale (VAS). A finite element model was developed and combined with the activation function (AF) to estimate neural activation. Electrical stimulation was perceived as significantly less sharp at the heel compared to all other sites, except one site in the forefoot (logistic regression, p < 0.05). The VAS scores were significantly higher in the arch than at the heel (RM ANOVA, p < 0.05). The model showed that the AF was between 91 and 231 % higher at the five other sites than at the heel. The differences in perception across the sole of the foot indicated that the CNS received different inputs depending on the stimulus site. The lower AF at the heel indicated that the skin thicknesses could contribute to the perceived differences.

Assessing clinical significance of treatment outcomes using the DASS-21.

PubMed

Ronk, Fiona R; Korman, James R; Hooke, Geoffrey R; Page, Andrew C

2013-12-01

Standard clinical significance classifications are based on movement between the "dysfunctional" and "functional" distributions; however, this dichotomy ignores heterogeneity within the "dysfunctional" population. Based on the methodology described by Tingey, Lambert, Burlingame, and Hansen (1996), the present study sought to present a 3-distribution clinical significance model for the 21-item version of the Depression Anxiety Stress Scales (DASS-21; P. F. Lovibond & Lovibond, 1995) using data from a normative sample (n = 2,914), an outpatient sample (n = 1,000), and an inpatient sample (n = 3,964). DASS-21 scores were collected at pre- and post-treatment for both clinical samples, and patients were classified into 1 of 5 categories based on whether they had made a reliable change and whether they had moved into a different functional range. Evidence supported the validity of the 3-distribution model for the DASS-21, since inpatients who were classified as making a clinically significant change showed lower symptom severity, higher perceived quality of life, and higher clinician-rated functioning than those who did not make a clinically significant change. Importantly, results suggest that the new category of recovering is an intermediate point between recovered and making no clinically significant change. Inpatients and outpatients have different treatment goals and therefore use of the concept of clinical significance needs to acknowledge differences in what constitutes a meaningful change. (c) 2013 APA, all rights reserved.

Complex functionality with minimal computation. Promise and pitfalls of reduced-tracer ocean biogeochemistry models

DOE PAGES

Galbraith, Eric D.; Dunne, John P.; Gnanadesikan, Anand; ...

2015-12-21

Earth System Models increasingly include ocean biogeochemistry models in order to predict changes in ocean carbon storage, hypoxia, and biological productivity under climate change. However, state-of-the-art ocean biogeochemical models include many advected tracers, that significantly increase the computational resources required, forcing a trade-off with spatial resolution. Here, we compare a state-of the art model with 30 prognostic tracers (TOPAZ) with two reduced-tracer models, one with 6 tracers (BLING), and the other with 3 tracers (miniBLING). The reduced-tracer models employ parameterized, implicit biological functions, which nonetheless capture many of the most important processes resolved by TOPAZ. All three are embedded inmore » the same coupled climate model. Despite the large difference in tracer number, the absence of tracers for living organic matter is shown to have a minimal impact on the transport of nutrient elements, and the three models produce similar mean annual preindustrial distributions of macronutrients, oxygen, and carbon. Significant differences do exist among the models, in particular the seasonal cycle of biomass and export production, but it does not appear that these are necessary consequences of the reduced tracer number. With increasing CO2, changes in dissolved oxygen and anthropogenic carbon uptake are very similar across the different models. Thus, while the reduced-tracer models do not explicitly resolve the diversity and internal dynamics of marine ecosystems, we demonstrate that such models are applicable to a broad suite of major biogeochemical concerns, including anthropogenic change. Lastly, these results are very promising for the further development and application of reduced-tracer biogeochemical models that incorporate ‘‘sub-ecosystem-scale’’ parameterizations.« less

Inter-species investigation of the mechano-regulation of bone healing: comparison of secondary bone healing in sheep and rat.

PubMed

Checa, Sara; Prendergast, Patrick J; Duda, Georg N

2011-04-29

Inter-species differences in regeneration exist in various levels. One aspect is the dynamics of bone regeneration and healing, e.g. small animals show a faster healing response when compared to large animals. Mechanical as well as biological factors are known to play a key role in the process. However, it remains so far unknown whether different animals follow at all comparable mechano-biological rules during tissue regeneration, and in particular during bone healing. In this study, we investigated whether differences observed in vivo in the dynamics of bone healing between rat and sheep are only due to differences in the animal size or whether these animals have a different mechano-biological response during the healing process. Histological sections from in vivo experiments were compared to in silico predictions of a mechano-biological computer model for the simulation of bone healing. Investigations showed that the healing processes in both animal models occur under significantly different levels of mechanical stimuli within the callus region, which could explain histological observations of early intramembranous ossification at the endosteal side. A species-specific adaptation of a mechano-biological model allowed a qualitative match of model predictions with histological observations. Specifically, when keeping cell activity processes at the same rate, the amount of tissue straining defining favorable mechanical conditions for the formation of bone had to be increased in the large animal model, with respect to the small animal, to achieve a qualitative agreement of model predictions with histological data. These findings illustrate that geometrical (size) differences alone cannot explain the distinctions seen in the histological appearance of secondary bone healing in sheep and rat. It can be stated that significant differences in the mechano-biological regulation of the healing process exist between these species. Future investigations should aim towards understanding whether these differences are due to differences in cell behavior, material properties of the newly formed tissues within the callus and/or differences in response to the mechanical environment. Copyright © 2011 Elsevier Ltd. All rights reserved.

A real-time spiking cerebellum model for learning robot control.

PubMed

Carrillo, Richard R; Ros, Eduardo; Boucheny, Christian; Coenen, Olivier J-M D

2008-01-01

We describe a neural network model of the cerebellum based on integrate-and-fire spiking neurons with conductance-based synapses. The neuron characteristics are derived from our earlier detailed models of the different cerebellar neurons. We tested the cerebellum model in a real-time control application with a robotic platform. Delays were introduced in the different sensorimotor pathways according to the biological system. The main plasticity in the cerebellar model is a spike-timing dependent plasticity (STDP) at the parallel fiber to Purkinje cell connections. This STDP is driven by the inferior olive (IO) activity, which encodes an error signal using a novel probabilistic low frequency model. We demonstrate the cerebellar model in a robot control system using a target-reaching task. We test whether the system learns to reach different target positions in a non-destructive way, therefore abstracting a general dynamics model. To test the system's ability to self-adapt to different dynamical situations, we present results obtained after changing the dynamics of the robotic platform significantly (its friction and load). The experimental results show that the cerebellar-based system is able to adapt dynamically to different contexts.

LIDAR vs. GEODAS land elevation data in hurricane induced inundation modelling

NASA Astrophysics Data System (ADS)

Peng, M.; Pietrafesa, L. J.; Bao, S.; Liu, H.; Xia, M.; Yan, T.

2007-04-01

LIDAR (Light Detection and Ranging) and GEODAS (GEOphysical DAta System) are respectively taken as the land elevation data for a 3-D storm surge and inundation model to investigate the subsequent inundation differences. Hilton Head, South Carolina, and Croatan-Albemarle-Pamlico Estuary System (CAPES), North Carolina, are the two investigated regions. Significant inundation differences with LIDAR versus GEODAS are found in both regions. The modeled inundation area with GEODAS is larger than with LIDAR. For Category 2-3 hypothetical hurricanes, the maximum inundation difference in Hilton Head region is 67%, while the difference in the CAPES is 156%. Generally, vertical precision difference of the two databases is the major reason for the inundation difference. Recently constructed man-made structures, not included in the GEODAS, but included in the LIDAR data sets may be another contributing reason.

CoRoT/ESTA TASK 1 and TASK 3 comparison of the internal structure and seismic properties of representative stellar models. Comparisons between the ASTEC, CESAM, CLES, GARSTEC and STAROX codes

NASA Astrophysics Data System (ADS)

Lebreton, Yveline; Montalbán, Josefina; Christensen-Dalsgaard, Jørgen; Roxburgh, Ian W.; Weiss, Achim

2008-08-01

We compare stellar models produced by different stellar evolution codes for the CoRoT/ESTA project, comparing their global quantities, their physical structure, and their oscillation properties. We discuss the differences between models and identify the underlying reasons for these differences. The stellar models are representative of potential CoRoT targets. Overall we find very good agreement between the five different codes, but with some significant deviations. We find noticeable discrepancies (though still at the per cent level) that result from the handling of the equation of state, of the opacities and of the convective boundaries. The results of our work will be helpful in interpreting future asteroseismology results from CoRoT.

Potent therapeutic effects of shouwu jiangqi decoction on polycystic ovary syndrome with insulin resistance in rats.

PubMed

Wang, Li-hong; Wang, Xu; Yu, Xi-zhong; Xu, Wen-ting

2016-02-01

To investigate the effect of Shouwu Jiangqi Decoction (SJD) on polycystic ovary syndrome (PCOS) with insulin resistance (IR) in rats and to explore the underlining molecular mechanisms. A total of 51 female Sprague-Dawley rats were randomly divided into 6 groups: control group (n=7), model group (n=8), SJD high-dose group (n=9), SJD medium-dose group (n=9), SJD low-dose group (n=9) and DMBG group (n=9). Radioimmunoassay was used to measure serum follicle-stimulating hormone (FSH), luteinizing hormone (LH) and testosterone concentrations and qRT-PCR and western blot were used to examine the expression levels of mRNA and protein respectively of insulin receptor substrate 1 (IRS-1) and phosphatidylinositide 3-kinases (PI3K) p85α in different groups. FSH level significantly decreased in the model group compared with the normal control (P<0.01), and high-dose SJD and DMBG can significantly increase FSH level (P<0.01). LH level showed a mild increase without statistic significance in the model group compared with the control and different dosages of SJD had no significance effect on LH level, while DMBG can significantly decrease LH level (P<0.01). Testosterone level significantly increased in the model group compared with the control group (P<0.01), and high-dose SJD and DMBG can significantly decrease testosterone level (P<0.01). The expression of IRS-1 as well as PI3Kp85α were significantly decreased in the model group compared with the normal control group at both mRNA (P<0.001) and protein (P<0.01) level, and both high-dose SJD and DMBG can enhance IRS-1 and PI3K expression (P<0.05). SJD has potent therapeutic effects on PCOS with IR in rats. The therapeutic effects of SJD on IR and ovulatory dysfunction are probably achieved through correcting the defective insulin signaling transduction.

Exploring the impact of different multi-level measures of physician communities in patient-centric care networks on healthcare outcomes: A multi-level regression approach.

PubMed

Uddin, Shahadat

2016-02-04

A patient-centric care network can be defined as a network among a group of healthcare professionals who provide treatments to common patients. Various multi-level attributes of the members of this network have substantial influence to its perceived level of performance. In order to assess the impact different multi-level attributes of patient-centric care networks on healthcare outcomes, this study first captured patient-centric care networks for 85 hospitals using health insurance claim dataset. From these networks, this study then constructed physician collaboration networks based on the concept of patient-sharing network among physicians. A multi-level regression model was then developed to explore the impact of different attributes that are organised at two levels on hospitalisation cost and hospital length of stay. For Level-1 model, the average visit per physician significantly predicted both hospitalisation cost and hospital length of stay. The number of different physicians significantly predicted only the hospitalisation cost, which has significantly been moderated by age, gender and Comorbidity score of patients. All Level-1 findings showed significance variance across physician collaboration networks having different community structure and density. These findings could be utilised as a reflective measure by healthcare decision makers. Moreover, healthcare managers could consider them in developing effective healthcare environments.

Reconciling transport models across scales: The role of volume exclusion

NASA Astrophysics Data System (ADS)

Taylor, P. R.; Yates, C. A.; Simpson, M. J.; Baker, R. E.

2015-10-01

Diffusive transport is a universal phenomenon, throughout both biological and physical sciences, and models of diffusion are routinely used to interrogate diffusion-driven processes. However, most models neglect to take into account the role of volume exclusion, which can significantly alter diffusive transport, particularly within biological systems where the diffusing particles might occupy a significant fraction of the available space. In this work we use a random walk approach to provide a means to reconcile models that incorporate crowding effects on different spatial scales. Our work demonstrates that coarse-grained models incorporating simplified descriptions of excluded volume can be used in many circumstances, but that care must be taken in pushing the coarse-graining process too far.

Differences in Water Vapor Radiative Transfer among 1D Models Can Significantly Affect the Inner Edge of the Habitable Zone

NASA Astrophysics Data System (ADS)

Yang, Jun; Leconte, Jérémy; Wolf, Eric T.; Goldblatt, Colin; Feldl, Nicole; Merlis, Timothy; Wang, Yuwei; Koll, Daniel D. B.; Ding, Feng; Forget, François; Abbot, Dorian S.

2016-08-01

An accurate estimate of the inner edge of the habitable zone is critical for determining which exoplanets are potentially habitable and for designing future telescopes to observe them. Here, we explore differences in estimating the inner edge among seven one-dimensional radiative transfer models: two line-by-line codes (SMART and LBLRTM) as well as five band codes (CAM3, CAM4_Wolf, LMDG, SBDART, and AM2) that are currently being used in global climate models. We compare radiative fluxes and spectra in clear-sky conditions around G and M stars, with fixed moist adiabatic profiles for surface temperatures from 250 to 360 K. We find that divergences among the models arise mainly from large uncertainties in water vapor absorption in the window region (10 μm) and in the region between 0.2 and 1.5 μm. Differences in outgoing longwave radiation increase with surface temperature and reach 10-20 W m-2 differences in shortwave reach up to 60 W m-2, especially at the surface and in the troposphere, and are larger for an M-dwarf spectrum than a solar spectrum. Differences between the two line-by-line models are significant, although smaller than among the band models. Our results imply that the uncertainty in estimating the insolation threshold of the inner edge (the runaway greenhouse limit) due only to clear-sky radiative transfer is ≈10% of modern Earth’s solar constant (I.e., ≈34 W m-2 in global mean) among band models and ≈3% between the two line-by-line models. These comparisons show that future work is needed that focuses on improving water vapor absorption coefficients in both shortwave and longwave, as well as on increasing the resolution of stellar spectra in broadband models.

DIFFERENCES IN WATER VAPOR RADIATIVE TRANSFER AMONG 1D MODELS CAN SIGNIFICANTLY AFFECT THE INNER EDGE OF THE HABITABLE ZONE

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

Yang, Jun; Wang, Yuwei; Leconte, Jérémy

An accurate estimate of the inner edge of the habitable zone is critical for determining which exoplanets are potentially habitable and for designing future telescopes to observe them. Here, we explore differences in estimating the inner edge among seven one-dimensional radiative transfer models: two line-by-line codes (SMART and LBLRTM) as well as five band codes (CAM3, CAM4-Wolf, LMDG, SBDART, and AM2) that are currently being used in global climate models. We compare radiative fluxes and spectra in clear-sky conditions around G and M stars, with fixed moist adiabatic profiles for surface temperatures from 250 to 360 K. We find thatmore » divergences among the models arise mainly from large uncertainties in water vapor absorption in the window region (10 μ m) and in the region between 0.2 and 1.5 μ m. Differences in outgoing longwave radiation increase with surface temperature and reach 10–20 W m{sup 2}; differences in shortwave reach up to 60 W m{sup 2}, especially at the surface and in the troposphere, and are larger for an M-dwarf spectrum than a solar spectrum. Differences between the two line-by-line models are significant, although smaller than among the band models. Our results imply that the uncertainty in estimating the insolation threshold of the inner edge (the runaway greenhouse limit) due only to clear-sky radiative transfer is ≈10% of modern Earth’s solar constant (i.e., ≈34 W m{sup 2} in global mean) among band models and ≈3% between the two line-by-line models. These comparisons show that future work is needed that focuses on improving water vapor absorption coefficients in both shortwave and longwave, as well as on increasing the resolution of stellar spectra in broadband models.« less

Effect of homeopathic Arnica montana on bruising in face-lifts: results of a randomized, double-blind, placebo-controlled clinical trial.

PubMed

Seeley, Brook M; Denton, Andrew B; Ahn, Min S; Maas, Corey S

2006-01-01

To design a model for performing reproducible, objective analyses of skin color changes and to apply this model to evaluate the efficacy of homeopathic Arnica montana as an antiecchymotic agent when taken perioperatively. Twenty-nine patients undergoing rhytidectomy at a tertiary care center were treated perioperatively with either homeopathic A. montana or placebo in a double-blind fashion. Postoperative photographs were analyzed using a novel computer model for color changes, and subjective assessments of postoperative ecchymosis were obtained. No subjective differences were noted between the treatment group and the control group, either by the patients or by the professional staff. No objective difference in the degree of color change was found. Patients receiving homeopathic A. montana were found to have a smaller area of ecchymosis on postoperative days 1, 5, 7, and 10. These differences were statistically significant (P<.05) only on postoperative days 1 (P<.005) and 7 (P<.001). This computer model provides an efficient, objective, and reproducible means with which to assess perioperative color changes, both in terms of area and degree. Patients taking perioperative homeopathic A. montana exhibited less ecchymosis, and that difference was statistically significant (P<.05) on 2 of the 4 postoperative data points evaluated.

Simulation of Urban Rainfall-Runoff in Piedmont Cities: A Case Study in Jinan City, China

NASA Astrophysics Data System (ADS)

Chang, X.; Xu, Z.; Zhao, G.; Li, H.

2017-12-01

During the past decades, frequent flooding disasters in urban areas resulted in catastrophic impacts such as human life casualties and property damages especially in piedmont cities due to its specific topography. In this study, a piedmont urban flooding model was developed in the Huangtaiqiao catchment based on SWMM. The sub-catchments in this piedmont area were divided into mountainous area, plain area and main urban area according to the variations of underlying surface topography. The impact of different routing mode and channel roughness on simulation results was quantitatively analyzed under different types of scenarios, and genetic algorithm was used to optimize model parameters. Results show that the simulation is poor (with a mean Nash coefficient of 0.61) when using the traditional routing mode in SWMM model, which usually ignores terrain variance in piedmont area. However, when the difference of routing mode, percent routed and channel roughness are considered, the prediction precision of model were significantly increased (with a mean Nash coefficient of 0.86), indicating that the difference of surface topography significantly affects the simulation results in piedmont cities. The relevant results would provide the scientific basis and technical support for rainfall-runoff simulation, flood control and disaster alleviation in piedmont cities.

Comparison of stretched-Exponential and monoexponential model diffusion-Weighted imaging in prostate cancer and normal tissues.

PubMed

Liu, Xiaohang; Zhou, Liangping; Peng, Weijun; Wang, He; Zhang, Yong

2015-10-01

To compare stretched-exponential and monoexponential model diffusion-weighted imaging (DWI) in prostate cancer and normal tissues. Twenty-seven patients with prostate cancer underwent DWI exam using b-values of 0, 500, 1000, and 2000 s/mm(2) . The distributed diffusion coefficients (DDC) and α values of prostate cancer and normal tissues were obtained with stretched-exponential model and apparent diffusion coefficient (ADC) values using monoexponential model. The ADC, DDC (both in 10(-3) mm(2)/s), and α values (range, 0-1) were compared among different prostate tissues. The ADC and DDC were also compared and correlated in each tissue, and the standardized differences between DDC and ADC were compared among different tissues. Data were obtained for 31 cancers, 36 normal peripheral zone (PZ) and 26 normal central gland (CG) tissues. The ADC (0.71 ± 0.12), DDC (0.60 ± 0.18), and α value (0.64 ± 0.05) of tumor were all significantly lower than those of the normal PZ (1.41 ± 0.22, 1.47 ± 0.20, and 0.85 ± 0.09) and CG (1.25 ± 0.14, 1.32 ± 0.13, and 0.82 ± 0.06) (all P < 0.05). ADC was significantly higher than DDC in cancer, but lower than DDC in the PZ and CG (all P < 0.05). The ADC and DDC were strongly correlated (R(2)  = 0.99, 0.98, 0.99, respectively, all P < 0.05) in all the tissue, and standardized difference between ADC and DDC of cancer was slight but significantly higher than that in normal tissue. The stretched-exponential model DWI provides more parameters for distinguishing prostate cancer and normal tissue and reveals slight differences between DDC and ADC values. © 2015 Wiley Periodicals, Inc.

[Comparison of treatment outcomes in patients with maxillary dentoalveolar protrusion by applying different anchorage methods: a three-dimensional model study].

PubMed

Ning, Ma; Weiran, Li

2015-02-01

This study aims to compare the treatment outcomes in patients with maxillary dentoalveolar protrusion by applying different anchorage methods via three-dimensional model measurement. A total of 46 patients with maxillary dentoalveolar protrusion treated with bilateral maxillary first premolar extractions and high anchorage were selected. The subjects were randomly divided into three groups according to the type of anchorage applied, which included implant, extraoral, and Nance arch anchorages. The maxillary dental models were made before treatment and after space closure of maxilla. The movements of the maxillary central incisors and first molars were measured via a three-dimensional model measurement, and the amounts of movement were compared among the three groups. The sagittal lingual movements of the maxillary central incisors were (-6.661 ± 1.328), (-5.939 ± 1.806), and (-5.788 ± 2.009) mm for the implant, extraoral, and Nance arch anchorage groups, respectively, with no significant difference among the three groups (P = 0.121). The corresponding vertical movements of the maxillary central incisors were (0.129 ± 1.815) mm intrusion, and (-2.162 ± 2.026), (-2.623 ± 1.776) mm extrusion. Significant difference was found between the implant anchorage group and the other groups (P < 0.05). The corresponding sagittal mesial movements of the maxillary first molars were (0.608 ± 1.045), (1.445 ± 1.462), and (1.503 ± 0.945) mm. The corresponding vertical movements of the maxillary first molars were (0.720 ± 0.805) mm intrusion, (0.076 ± 0.986) mm intrusion, and (-0.072 ± 0.690) mm extrusion. Significant difference was found between the implant anchorage group and the other two groups (P < 0.05). In the transverse direction, the first molars all moved lingually with no significant difference among the three groups (P > 0.05). Implant anchorage may be superior in the vertical control of the maxillary incisors and in the sagittal, as well as in the vertical control of the maxillary molars, compared with the traditional anchorages during the treatment of patients with maxillary dentoalveolar protrusion.

High-Resolution Dynamical Downscaling Ensemble Projections of Future Extreme Temperature Distributions for the United States

NASA Astrophysics Data System (ADS)

Zobel, Zachary; Wang, Jiali; Wuebbles, Donald J.; Kotamarthi, V. Rao

2017-12-01

The aim of this study is to examine projections of extreme temperatures over the continental United States (CONUS) for the 21st century using an ensemble of high spatial resolution dynamically downscaled model simulations with different boundary conditions. The downscaling uses the Weather Research and Forecast model at a spatial resolution of 12 km along with outputs from three different Coupled Model Intercomparison Project Phase 5 global climate models that provide boundary conditions under two different future greenhouse gas (GHG) concentration trajectories. The results from two decadal-length time slices (2045-2054 and 2085-2094) are compared with a historical decade (1995-2004). Probability density functions of daily maximum/minimum temperatures are analyzed over seven climatologically cohesive regions of the CONUS. The impacts of different boundary conditions as well as future GHG concentrations on extreme events such as heat waves and days with temperature higher than 95°F are also investigated. The results show that the intensity of extreme warm temperature in future summer is significantly increased, while the frequency of extreme cold temperature in future winter decreases. The distribution of summer daily maximum temperature experiences a significant warm-side shift and increased variability, while the distribution of winter daily minimum temperature is projected to have a less significant warm-side shift with decreased variability. Using "business-as-usual" scenario, 5-day heat waves are projected to occur at least 5-10 times per year in most CONUS and ≥95°F days will increase by 1-2 months by the end of the century.

Modeling Chemotherapeutic Neurotoxicity with Human Induced Pluripotent Stem Cell-Derived Neuronal Cells

PubMed Central

Wheeler, Heather E.; Wing, Claudia; Delaney, Shannon M.; Komatsu, Masaaki; Dolan, M. Eileen

2015-01-01

There are no effective agents to prevent or treat chemotherapy-induced peripheral neuropathy (CIPN), the most common non-hematologic toxicity of chemotherapy. Therefore, we sought to evaluate the utility of human neuron-like cells derived from induced pluripotent stem cells (iPSCs) as a means to study CIPN. We used high content imaging measurements of neurite outgrowth phenotypes to compare the changes that occur to iPSC-derived neuronal cells among drugs and among individuals in response to several classes of chemotherapeutics. Upon treatment of these neuronal cells with the neurotoxic drug paclitaxel, vincristine or cisplatin, we identified significant differences in five morphological phenotypes among drugs, including total outgrowth, mean/median/maximum process length, and mean outgrowth intensity (P < 0.05). The differences in damage among drugs reflect differences in their mechanisms of action and clinical CIPN manifestations. We show the potential of the model for gene perturbation studies by demonstrating decreased expression of TUBB2A results in significantly increased sensitivity of neurons to paclitaxel (0.23 ± 0.06 decrease in total neurite outgrowth, P = 0.011). The variance in several neurite outgrowth and apoptotic phenotypes upon treatment with one of the neurotoxic drugs is significantly greater between than within neurons derived from four different individuals (P < 0.05), demonstrating the potential of iPSC-derived neurons as a genetically diverse model for CIPN. The human neuron model will allow both for mechanistic studies of specific genes and genetic variants discovered in clinical studies and for screening of new drugs to prevent or treat CIPN. PMID:25689802

An efficient parallel sampling technique for Multivariate Poisson-Lognormal model: Analysis with two crash count datasets

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

Zhan, Xianyuan; Aziz, H. M. Abdul; Ukkusuri, Satish V.

Our study investigates the Multivariate Poisson-lognormal (MVPLN) model that jointly models crash frequency and severity accounting for correlations. The ordinary univariate count models analyze crashes of different severity level separately ignoring the correlations among severity levels. The MVPLN model is capable to incorporate the general correlation structure and takes account of the over dispersion in the data that leads to a superior data fitting. But, the traditional estimation approach for MVPLN model is computationally expensive, which often limits the use of MVPLN model in practice. In this work, a parallel sampling scheme is introduced to improve the original Markov Chainmore » Monte Carlo (MCMC) estimation approach of the MVPLN model, which significantly reduces the model estimation time. Two MVPLN models are developed using the pedestrian vehicle crash data collected in New York City from 2002 to 2006, and the highway-injury data from Washington State (5-year data from 1990 to 1994) The Deviance Information Criteria (DIC) is used to evaluate the model fitting. The estimation results show that the MVPLN models provide a superior fit over univariate Poisson-lognormal (PLN), univariate Poisson, and Negative Binomial models. Moreover, the correlations among the latent effects of different severity levels are found significant in both datasets that justifies the importance of jointly modeling crash frequency and severity accounting for correlations.« less

An efficient parallel sampling technique for Multivariate Poisson-Lognormal model: Analysis with two crash count datasets

DOE PAGES

Zhan, Xianyuan; Aziz, H. M. Abdul; Ukkusuri, Satish V.

2015-11-19

Our study investigates the Multivariate Poisson-lognormal (MVPLN) model that jointly models crash frequency and severity accounting for correlations. The ordinary univariate count models analyze crashes of different severity level separately ignoring the correlations among severity levels. The MVPLN model is capable to incorporate the general correlation structure and takes account of the over dispersion in the data that leads to a superior data fitting. But, the traditional estimation approach for MVPLN model is computationally expensive, which often limits the use of MVPLN model in practice. In this work, a parallel sampling scheme is introduced to improve the original Markov Chainmore » Monte Carlo (MCMC) estimation approach of the MVPLN model, which significantly reduces the model estimation time. Two MVPLN models are developed using the pedestrian vehicle crash data collected in New York City from 2002 to 2006, and the highway-injury data from Washington State (5-year data from 1990 to 1994) The Deviance Information Criteria (DIC) is used to evaluate the model fitting. The estimation results show that the MVPLN models provide a superior fit over univariate Poisson-lognormal (PLN), univariate Poisson, and Negative Binomial models. Moreover, the correlations among the latent effects of different severity levels are found significant in both datasets that justifies the importance of jointly modeling crash frequency and severity accounting for correlations.« less

Narrative review of frameworks for translating research evidence into policy and practice.

PubMed

Milat, Andrew J; Li, Ben

2017-02-15

A significant challenge in research translation is that interested parties interpret and apply the associated terms and conceptual frameworks in different ways. The purpose of this review was to: a) examine different research translation frameworks; b) examine the similarities and differences between the frameworks; and c) identify key strengths and weaknesses of the models when they are applied in practice. The review involved a keyword search of PubMed. The search string was (translational research OR knowledge translation OR evidence to practice) AND (framework OR model OR theory) AND (public health OR health promotion OR medicine). Included studies were published in English between January 1990 and December 2014, and described frameworks, models or theories associated with research translation. The final review included 98 papers, and 41 different frameworks and models were identified. The most frequently applied knowledge translation framework in the literature was RE-AIM, followed by the knowledge translation continuum or 'T' models, the Knowledge to Action framework, the PARiHS framework, evidence based public health models, and the stages of research and evaluation model. The models identified in this review stem from different fields, including implementation science, basic and medical sciences, health services research and public health, and propose different but related pathways to closing the research-practice gap.

75 FR 46868 - Airworthiness Directives; The Boeing Company Model 747 Airplanes and Model 767 Airplanes Equipped...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-04

... crystal accretion. However, at this time, we do not agree to pursue research to develop an ice detector... significantly different type-design booster from that of the GE Model CF6-80C2 series engines (GE Model CF6-80A... events recorded on GE Model CF6-80A series engines. While this engine has a similar compressor design...

Measurement of In Vitro Single Cell Temperature by Novel Thermocouple Nanoprobe in Acute Lung Injury Models.

PubMed

Wang, Xing; Chen, Qiuhua; Tian, Wenjuan; Wang, Jianqing; Cheng, Lu; Lu, Jun; Chen, Mingqi; Pei, Yinhao; Li, Can; Chen, Gong; Gu, Ning

2017-01-01

Energy metabolism may alter pattern differences in acute lung injury (ALI) as one of the causes but the detailed features at single-cellular level remain unclear. Changes in intercellular temperature and adenosine triphosphate (ATP) concentration within the single cell may help to understand the role of energy metabolism in causing ALI. ALI in vitro models were established by treating mice lung epithelial (MLE-12) cells with lipopolysaccharide (LPS), hydrogen peroxide (H2O2), hydrochloric acid (HCl) and cobalt chloride (CoCl2, respectively. 100 nm micro thermocouple probe (TMP) was inserted into the cytosol by micromanipulation system and thermoelectric readings were recorded to calculate the intracellular temperature based on standard curve. The total ATP contents for the MLE-12 cells were evaluated at different time intervals after treatments. A significant increase of intracellular temperature was observed after 10 or 20 μg/L LPS and HCl treatments. The HCl increased the temperature in a dose-dependent manner. On the contrary, H2O2 induced a significant decline of intracellular temperature after treatment. No significant difference in intracellular temperature was observed after CoCl2 exposure. The intracellular ATP levels decreased in a time-dependent manner after treatment with H2O2 and HCl, while the LPS and CoCl2 had no significant effect on ATP levels. The intracellular temperature responses varied in different ALI models. The concentration of ATP in the MLE-12 cells played part in the intracellular temperature changes. No direct correlation was observed between the intracellular temperature and concentration of ATP in the MLE-12 cells.

Addressing the mischaracterization of extreme rainfall in regional climate model simulations - A synoptic pattern based bias correction approach

NASA Astrophysics Data System (ADS)

Li, Jingwan; Sharma, Ashish; Evans, Jason; Johnson, Fiona

2018-01-01

Addressing systematic biases in regional climate model simulations of extreme rainfall is a necessary first step before assessing changes in future rainfall extremes. Commonly used bias correction methods are designed to match statistics of the overall simulated rainfall with observations. This assumes that change in the mix of different types of extreme rainfall events (i.e. convective and non-convective) in a warmer climate is of little relevance in the estimation of overall change, an assumption that is not supported by empirical or physical evidence. This study proposes an alternative approach to account for the potential change of alternate rainfall types, characterized here by synoptic weather patterns (SPs) using self-organizing maps classification. The objective of this study is to evaluate the added influence of SPs on the bias correction, which is achieved by comparing the corrected distribution of future extreme rainfall with that using conventional quantile mapping. A comprehensive synthetic experiment is first defined to investigate the conditions under which the additional information of SPs makes a significant difference to the bias correction. Using over 600,000 synthetic cases, statistically significant differences are found to be present in 46% cases. This is followed by a case study over the Sydney region using a high-resolution run of the Weather Research and Forecasting (WRF) regional climate model, which indicates a small change in the proportions of the SPs and a statistically significant change in the extreme rainfall over the region, although the differences between the changes obtained from the two bias correction methods are not statistically significant.

Effect of stress on the diffusion kinetics of methane during gas desorption in coal matrix under different equilibrium pressures

NASA Astrophysics Data System (ADS)

Li, Chengwu; Xue, Honglai; Hu, Po; Guan, Cheng; Liu, Wenbiao

2018-06-01

Stress has a significant influence on gas diffusion, which is a key factor for methane recovery in coal mines. In this study, a series of experiments were performed to investigate effect of stress on the gas diffusivity during desorption in tectonic coal. Additionally, the desorbed data were modeled using the unipore and bidisperse models. The results show that the bidisperse model better describes the diffusion kinetics than the unipore model in this study. Additionally, the modeling results using the bidisperse approach suggest that the stress impact on the macropore diffusivity is greater than the stress on the micropore diffusivity. Under the same equilibrium pressure, the diffusivity varies with stress according to a four-stage function, which shows an ‘M-shape’. As the equilibrium gas pressure increased from 0.6 to 1.7 MPa, the critical point between stage 2 and stage 3 and between stage 3 and stage 4 transferred to a low stress. This difference is attributed to the gas pressure effects on the physical and mechanical properties of coal. These observations indicate that both the stress and gas pressure can significantly impact gas diffusion and may have significant implications on methane recovery in coal mines.

Peritoneal fluid transport in CAPD patients with different transport rates of small solutes.

PubMed

Sobiecka, Danuta; Waniewski, Jacek; Weryński, Andrzej; Lindholm, Bengt

2004-01-01

Continuous ambulatory peritoneal dialysis (CAPD) patients with high peritoneal solute transport rate often have inadequate peritoneal fluid transport. It is not known whether this inadequate fluid transport is due solely to a too rapid fall of osmotic pressure, or if the decreased effectiveness of fluid transport is also a contributing factor. To analyze fluid transport parameters and the effectiveness of dialysis fluid osmotic pressure in the induction of fluid flow in CAPD patients with different small solute transport rates. 44 CAPD patients were placed in low (n = 6), low-average (n = 13), high-average (n = 19), and high (n = 6) transport groups according to a modified peritoneal equilibration test (PET). The study involved a 6-hour peritoneal dialysis dwell with 2 L 3.86% glucose dialysis fluid for each patient. Radioisotopically labeled serum albumin was added as a volume marker.The fluid transport parameters (osmotic conductance and fluid absorption rate) were estimated using three mathematical models of fluid transport: (1) Pyle model (model P), which describes ultrafiltration rate as an exponential function of time; (2) model OS, which is based on the linear relationship of ultrafiltration rate and overall osmolality gradient between dialysis fluid and blood; and (3) model G, which is based on the linear relationship between ultrafiltration rate and glucose concentration gradient between dialysis fluid and blood. Diffusive mass transport coefficients (K(BD)) for glucose, urea, creatinine, potassium, and sodium were estimated using the modified Babb-Randerson-Farrell model. The high transport group had significantly lower dialysate volume and glucose and osmolality gradients between dialysate and blood, but significantly higher K(BD) for small solutes compared with the other transport groups. Osmotic conductance, fluid absorption rate, and initial ultrafiltration rate did not differ among the transport groups for model OS and model P. Model G yielded unrealistic values of fluid transport parameters that differed from those estimated by models OS and P. The K(BD) values for small solutes were significantly different among the groups, and did not correlate with fluid transport parameters for model OS. The difference in fluid transport between the different transport groups was due only to the differences in the rate of disappearance of the overall osmotic pressure of the dialysate, which was a combined result of the transport rate of glucose and other small solutes. Although the glucose gradient is the major factor influencing ultrafiltration rate, other solutes, such as urea, are also of importance. The counteractive effect of plasma small solutes on transcapillary ultrafiltration was found to be especially notable in low transport patients. Thus, glucose gradient alone should not be considered the only force that shapes the ultrafiltration profile during peritoneal dialysis. We did not find any correlations between diffusive mass transport coefficients for small solutes and fluid transport parameters such as osmotic conductance or fluid and volume marker absorption. We may thus conclude that the pathway(s) for fluid transport appears to be partly independent from the pathway(s) for small solute transport, which supports the hypothesis of different pore types for fluid and solute transport.

Predictors of physical performance and functional ability in people 50+ with and without fibromyalgia.

PubMed

Jones, C Jessie; Rutledge, Dana N; Aquino, Jordan

2010-07-01

The purposes of this study were to determine whether people with and without fibromyalgia (FM) age 50 yr and above showed differences in physical performance and perceived functional ability and to determine whether age, gender, depression, and physical activity level altered the impact of FM status on these factors. Dependent variables included perceived function and 6 performance measures (multidimensional balance, aerobic endurance, overall functional mobility, lower body strength, and gait velocity-normal or fast). Independent (predictor) variables were FM status, age, gender, depression, and physical activity level. Results indicated significant differences between adults with and without FM on all physical-performance measures and perceived function. Linear-regression models showed that the contribution of significant predictors was in expected directions. All regression models were significant, accounting for 16-65% of variance in the dependent variables.

The Effect of Teaching Games of Understanding as a Coaching Instruction had on Adjust, Cover and Heart Rate among Malaysian and Indian Junior Hockey Players.

PubMed

Nathan, Sanmuga

2017-06-20

The field hockey coaching process across both Malaysia and India favours a traditional, coach-centred approach of mastering technical skills in terms of game play parameters, fitness, intensity, and load training, whereas a tactical- and player-centred pedagogical approach still takes a backseat. On the other hand, the Teaching Games for Understanding (TGfU) model offers tactical-cognitive instruction and is gaining international recognition for its ability to produce intelligent players via a problem-solving approach in game play. Therefore, the purpose of this quasi-experimental study was to investigate the effect of TGfU compared to skill mastery instruction, termed as Skill Drill Technical (SDT), among Malaysian and Indian elite junior hockey players in term of the game play attributes of adjust and cover in 5 vs. 5 small-sided game play and game play intensity via heart rate (HR) at different points of game play. A total of n = 60 players with an average age of 15 ± 1.03 was selected via simple random sampling from both countries involved in this study and assigned equally to groups, with 15 per group for TGfU and for SDT across Malaysia and India. Gathered data were analysed using the ANOVA and ANCOVA techniques. Findings indicated that there were no significant differences for adjust in 5 vs. 5 game play between TGfU and SDT across Malaysia and India after the intervention. For cover, there was significant improvement for Malaysian players using the TGfU model compared to SDT. In contrast, there was no significant difference between these two models among the Indian players after the intervention. There was significant difference between these two models in terms of warm-up HR across the two countries, and HR was higher via TGfU. For HR immediately after the 5 vs. 5 game play intervention and HR after three minutes' recovery, Indian players with TGfU recorded a higher and significant difference compared to SDT. However, findings indicated no significant difference between these two instruction types among Malaysians, although TGfU proved to have higher HR intensity. Therefore, these findings reiterated that TGfU is a useful approach for game play to enhance intensity and cardiac output. In conclusion, for TGfU to be more relevant to the coaching environment, future research should link game play and physiological parameters. TGfU should able to overcome the barriers of tradition and cultural background that may hinder its momentum.

Non-Gaussian PDF Modeling of Turbulent Boundary Layer Fluctuating Pressure Excitation

NASA Technical Reports Server (NTRS)

Steinwolf, Alexander; Rizzi, Stephen A.

2003-01-01

The purpose of the study is to investigate properties of the probability density function (PDF) of turbulent boundary layer fluctuating pressures measured on the exterior of a supersonic transport aircraft. It is shown that fluctuating pressure PDFs differ from the Gaussian distribution even for surface conditions having no significant discontinuities. The PDF tails are wider and longer than those of the Gaussian model. For pressure fluctuations upstream of forward-facing step discontinuities and downstream of aft-facing step discontinuities, deviations from the Gaussian model are more significant and the PDFs become asymmetrical. Various analytical PDF distributions are used and further developed to model this behavior.

[Modelling metallic bars in an orthopaedic laboratory: postural and biomechanical analysis].

PubMed

Draicchio, F; Miccio, A; Mari, S; Silvetti, A; Forzano, F; Ranavolo, A

2012-01-01

Aim of this work is to assess, with an objective technique (i.e. surface electromyography), the upper limb biomechanical load in workers specialized in manufacturing of orthopedic prostheses. We considered two different working configurations (workstation height at 105 and 110 cm) and three different materials to be modeled (aluminum, steel and titanium). Our results showed significant differences between aluminum/steel and titanium bars. As regards the working configurations, we found differences in the muscle activation patterns between the two heights, with an increased exertion of the shoulder muscles at 110 cm with respect to 105.

Interpretation reduces ecological impacts of visitors to world heritage site.

PubMed

Littlefair, Carolyn; Buckley, Ralf

2008-07-01

Minimal-impact interpretation is widely used to reduce the ecological impacts of visitors to protected areas. We tested whether verbal appeals and/or role-model demonstrations of minimal-impact behavior by a trained guide reduced noise, litter, and trampling impacts on hiking trails in a subtropical rainforest. Interpretation did reduce impacts significantly. Different interpretive techniques were more effective for different impacts. The experimental groups were mature, well-educated professionals; interpretation may differ in effectiveness for different visitors. Interpretation by skilled guides can indeed reduce visitor impacts in protected areas, especially if role modeling is combined with verbal appeals.

A Comparison of the Cheater Detection and the Unrelated Question Models: A Randomized Response Survey on Physical and Cognitive Doping in Recreational Triathletes

PubMed Central

Schröter, Hannes; Studzinski, Beatrix; Dietz, Pavel; Ulrich, Rolf; Striegel, Heiko; Simon, Perikles

2016-01-01

Purpose This study assessed the prevalence of physical and cognitive doping in recreational triathletes with two different randomized response models, that is, the Cheater Detection Model (CDM) and the Unrelated Question Model (UQM). Since both models have been employed in assessing doping, the major objective of this study was to investigate whether the estimates of these two models converge. Material and Methods An anonymous questionnaire was distributed to 2,967 athletes at two triathlon events (Frankfurt and Wiesbaden, Germany). Doping behavior was assessed either with the CDM (Frankfurt sample, one Wiesbaden subsample) or the UQM (one Wiesbaden subsample). A generalized likelihood-ratio test was employed to check whether the prevalence estimates differed significantly between models. In addition, we compared the prevalence rates of the present survey with those of a previous study on a comparable sample. Results After exclusion of incomplete questionnaires and outliers, the data of 2,017 athletes entered the final data analysis. Twelve-month prevalence for physical doping ranged from 4% (Wiesbaden, CDM and UQM) to 12% (Frankfurt CDM), and for cognitive doping from 1% (Wiesbaden, CDM) to 9% (Frankfurt CDM). The generalized likelihood-ratio test indicated no differences in prevalence rates between the two methods. Furthermore, there were no significant differences in prevalences between the present (undertaken in 2014) and the previous survey (undertaken in 2011), although the estimates tended to be smaller in the present survey. Discussion The results suggest that the two models can provide converging prevalence estimates. The high rate of cheaters estimated by the CDM, however, suggests that the present results must be seen as a lower bound and that the true prevalence of doping might be considerably higher. PMID:27218830

Comparison of reconstructed rapid prototyping models produced by 3-dimensional printing and conventional stone models with different degrees of crowding.

PubMed

Wan Hassan, Wan Nurazreena; Yusoff, Yusnilawati; Mardi, Noor Azizi

2017-01-01

Rapid prototyping models can be reconstructed from stereolithographic digital study model data to produce hard-copy casts. In this study, we aimed to compare agreement and accuracy of measurements made with rapid prototyping and stone models for different degrees of crowding. The Z Printer 450 (3D Systems, Rock Hill, SC) reprinted 10 sets of models for each category of crowding (mild, moderate, and severe) scanned using a structured-light scanner (Maestro 3D, AGE Solutions, Pisa, Italy). Stone and RP models were measured using digital calipers for tooth sizes in the mesiodistal, buccolingual, and crown height planes and for arch dimension measurements. Bland-Altman and paired t test analyses were used to assess agreement and accuracy. Clinical significance was set at ±0.50 mm. Bland-Altman analysis showed the mean bias of measurements between the models to be within ±0.15 mm (SD, ±0.40 mm), but the 95% limits of agreement exceeded the cutoff point of ±0.50 mm (lower range, -0.81 to -0.41 mm; upper range, 0.34 to 0.76 mm). Paired t tests showed statistically significant differences for all planes in all categories of crowding except for crown height in the moderate crowding group and arch dimensions in the mild and moderate crowding groups. The rapid prototyping models were not clinically comparable with conventional stone models regardless of the degree of crowding. Copyright © 2017 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

Is a Swine Model of Arteriovenous Malformation Suitable for Human Extracranial Arteriovenous Malformation? A Preliminary Study

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

Lv, Ming-ming, E-mail: lvmingming001@163.com; Fan, Xin-dong, E-mail: fanxindong@yahoo.com.cn; Su, Li-xin, E-mail: sulixin1975@126.com

Objective: A chronic arteriovenous malformation (AVM) model using the swine retia mirabilia (RMB) was developed and compared with the human extracranial AVM (EAVM) both in hemodynamics and pathology, to see if this brain AVM model can be used as an EAVM model. Methods: We created an arteriovenous fistula between the common carotid artery and the external jugular vein in eight animals by using end-to-end anastomosis. All animals were sacrificed 1 month after surgery, and the bilateral retia were obtained at autopsy and performed hematoxylin and eosin staining and immunohistochemistry. Pre- and postsurgical hemodynamic evaluations also were conducted. Then, the bloodmore » flow and histological changes of the animal model were compared with human EAVM. Results: The angiography after operation showed that the blood flow, like human EAVM, flowed from the feeding artery, via the nidus, drained to the draining vein. Microscopic examination showed dilated lumina and disrupted internal elastic lamina in both RMB of model and nidus of human EAVM, but the thickness of vessel wall had significant difference. Immunohistochemical reactivity for smooth muscle actin, angiopoietin 1, and angiopoietin 2 were similar in chronic model nidus microvessels and human EAVM, whereas vascular endothelial growth factor was significant difference between human EAVM and RMB of model. Conclusions: The AVM model described here is similar to human EAVM in hemodynamics and immunohistochemical features, but there are still some differences in anatomy and pathogenetic mechanism. Further study is needed to evaluate the applicability and efficacy of this model.« less

[Variation of long-chain 3-hydroxyacyl-CoA dehydrogenase DNA methylation in placenta of different preeclampsia-like mouse models].

PubMed

Han, Yiwei; Yang, Zi; Ding, Xiaoyan; Yu, Huan; Yi, Yanhong

2015-10-01

By detecting the variation of long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) DNA methylation in preeclampsia-like mouse models generated by different ways, to explore the roles of multifactor and multiple pathways in preeclampsia pathogenesis on molecular basis. Established preeclampsia-like mouse models in different ways and divided into groups as follows: (1) Nw-nitro-L-arginine-methyl ester (L-NAME) group: wild-type pregnant mouse received subcutaneous injection of L-NAME; (2) lipopolysaccharide (LPS) group: wild-type pregnant mouse received intraperitoneal injection of LPS; (3) apolipoprotein C-III (ApoC3) group: ApoC3 transgenic pregnant mouse with dysregulated lipid metabolism received subcutaneous injection of L-NAME; (4) β2 glycoprotein I (β-2GPI) group: wild-type pregnant mouse received subcutaneous injection of β-2GPI. According to the first injection time (on day 3, 11, 16 respectively), the L-NAME, LPS and ApoC3 groups were further subdivided into: pre-implantation (PI) experimental stage, early gestation (EG) experimental stage, and late gestation (LG) experimental stage. β-2GPI group was only injected before implantation. LCHAD gene methylation levels in placental were detected in different experimental stage. Normal saline control groups were set within wild-type and ApoC3 transgenic pregnant mice simultaneously. (1) CG sites in LCHAD DNA: 45 CG sites were detected in the range of 728 bp before LCHAD gene transcription start site, the 5, 12, 13, 14, 15, 16, 19, 24, 25, 27, 28, 29, 30, 31, 32, 34, 35, 43 CG sites were complex sites which contained two or more CG sequences, others were single site which contained one CG sequence. The 3, 5, 6, 11, 13, 14, 18, 28 sites in L-NAME, LPS, ApoC3 and β-2GPI groups showed different high levels of methylation; the 16, 25, 31, 42, 44 sites showed different low levels of methylation; other 32 sites were unmethylated. (2) Comparison of LCHAD gene methylation between different groups: the methylation levels of LCAHD gene at 3, 11, 13, 14, 18 sites in L-NAME, LPS, ApoC3 and β-2GPI groups were significantly higher than those in the normal saline control group (P < 0.05); and the methylation levels of 42, 44 sites in these groups were significantly lower than those in the normal saline control group (P < 0.05). (3) Methylation of LCHAD gene at the same site between different experimental stages: ① The 3, 11, 18 sites of EG experimental stage was significantly lower than PI and LG experimental stage in L-NAME group (P < 0.05); the 3, 11, 18 sites of PI experimental stage was significantly lower than EG and LG experimental stage in LPS group (P < 0.05); these sites of PI experimental stage was significantly higher than EG and LG experimental stages in ApoC3 group (P < 0.05). ② The methylation of site 5 in L-NAME and LPS groups were significantly higher than that of the normal saline control group (P < 0.05), and the LG experimental stages were significantly higher than other stages, but in ApoC3 group, only PI and EG stages were significantly higher than the normal saline control group (P < 0.05). ③ At site 6 in L-NAME group which showed high methylation level was significantly higher than the same site in other groups which showed low methylation level (P < 0.05). ④ At 13, 14 sites, earlier preeclampsia onset caused a lower methylation level in L-NAME group, but PI experimental stage was significantly higher than EG and LG experimental stages in LPS group (P < 0.05), EG experimental stage was significantly higher than PI and LG experimental stages in ApoC3 group (P < 0.05). ⑤ At site 28, earlier preeclampsia onset caused a higher methylation level in L-NAME group, but PI experimental stage was significantly lower than EG and LG experimental stages in LPS group (P < 0.05), EG experimental stage was significantly higher than PI and LG experimental stages in ApoC3 group (P < 0.05). ⑥ The 16, 25, 31 sites in ApoC3 group were significantly higher than other groups (P < 0.05). ⑦ At site 42 in β-2GPI group was unmethylated, but it in other groups showed low methylation level, the methylation level of site 42 in β-2GPI group was significantly lower than that in other groups (P < 0.05). The methylation of 6 and 42 CG sites may be related to LCHAD gene expression in placenta of L-NAME and β-2GPI induced preeclampsia-like models respectively; LCHAD gene expression and DNA methylation may not have obvious correlation in LPS and ApoC3 induced preeclampsia-like models. Differences exist in LCHAD DNA methylation in preeclampsia-like models generated by different ways, revealed a molecular basis to expand our understanding of the multi-factorial pathogenesis of preeclampsia.

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

Ahlgren, Björn; Larsson, Josefin; Nymark, Tanja

The origin of the prompt emission in gamma-ray bursts (GRBs) is still an unsolved problem and several different mechanisms have been suggested. We fit Fermi GRB data with a photospheric emission model which includes dissipation of the jet kinetic energy below the photosphere. The resulting spectra are dominated by Comptonization and contain no significant contribution from synchrotron radiation. In order to fit to the data, we span a physically motivated part of the model's parameter space and create DREAM (Dissipation with Radiative Emission as A table Model), a table model for XSPEC. Here, we show that this model can describemore » different kinds of GRB spectra, including GRB 090618, representing a typical Band function spectrum, and GRB 100724B, illustrating a double peaked spectrum, previously fitted with a Band+blackbody model, suggesting they originate from a similar scenario. We also suggest that the main difference between these two types of bursts is the optical depth at the dissipation site.« less

Escherichia coli growth under modeled reduced gravity

NASA Technical Reports Server (NTRS)

Baker, Paul W.; Meyer, Michelle L.; Leff, Laura G.

2004-01-01

Bacteria exhibit varying responses to modeled reduced gravity that can be simulated by clino-rotation. When Escherichia coli was subjected to different rotation speeds during clino-rotation, significant differences between modeled reduced gravity and normal gravity controls were observed only at higher speeds (30-50 rpm). There was no apparent affect of removing samples on the results obtained. When E. coli was grown in minimal medium (at 40 rpm), cell size was not affected by modeled reduced gravity and there were few differences in cell numbers. However, in higher nutrient conditions (i.e., dilute nutrient broth), total cell numbers were higher and cells were smaller under reduced gravity compared to normal gravity controls. Overall, the responses to modeled reduced gravity varied with nutrient conditions; larger surface to volume ratios may help compensate for the zone of nutrient depletion around the cells under modeled reduced gravity.

Testing statistical self-similarity in the topology of river networks

USGS Publications Warehouse

Troutman, Brent M.; Mantilla, Ricardo; Gupta, Vijay K.

2010-01-01

Recent work has demonstrated that the topological properties of real river networks deviate significantly from predictions of Shreve's random model. At the same time the property of mean self-similarity postulated by Tokunaga's model is well supported by data. Recently, a new class of network model called random self-similar networks (RSN) that combines self-similarity and randomness has been introduced to replicate important topological features observed in real river networks. We investigate if the hypothesis of statistical self-similarity in the RSN model is supported by data on a set of 30 basins located across the continental United States that encompass a wide range of hydroclimatic variability. We demonstrate that the generators of the RSN model obey a geometric distribution, and self-similarity holds in a statistical sense in 26 of these 30 basins. The parameters describing the distribution of interior and exterior generators are tested to be statistically different and the difference is shown to produce the well-known Hack's law. The inter-basin variability of RSN parameters is found to be statistically significant. We also test generator dependence on two climatic indices, mean annual precipitation and radiative index of dryness. Some indication of climatic influence on the generators is detected, but this influence is not statistically significant with the sample size available. Finally, two key applications of the RSN model to hydrology and geomorphology are briefly discussed.

The effects of modeling instruction on high school physics academic achievement

NASA Astrophysics Data System (ADS)

Wright, Tiffanie L.

The purpose of this study was to explore whether Modeling Instruction, compared to traditional lecturing, is an effective instructional method to promote academic achievement in selected high school physics classes at a rural middle Tennessee high school. This study used an ex post facto , quasi-experimental research methodology. The independent variables in this study were the instructional methods of teaching. The treatment variable was Modeling Instruction and the control variable was traditional lecture instruction. The Treatment Group consisted of participants in Physical World Concepts who received Modeling Instruction. The Control Group consisted of participants in Physical Science who received traditional lecture instruction. The dependent variable was gains scores on the Force Concepts Inventory (FCI). The participants for this study were 133 students each in both the Treatment and Control Groups (n = 266), who attended a public, high school in rural middle Tennessee. The participants were administered the Force Concepts Inventory (FCI) prior to being taught the mechanics of physics. The FCI data were entered into the computer-based Statistical Package for the Social Science (SPSS). Two independent samples t-tests were conducted to answer the research questions. There was a statistically significant difference between the treatment and control groups concerning the instructional method. Modeling Instructional methods were found to be effective in increasing the academic achievement of students in high school physics. There was no statistically significant difference between FCI gains scores for gender. Gender was found to have no effect on the academic achievement of students in high school physics classes. However, even though there was not a statistically significant difference, female students' gains scores were higher than male students' gains scores when Modeling Instructional methods of teaching were used. Based on these findings, it is recommended that high school science teachers should use Modeling Instructional methods of teaching daily in their classrooms. A recommendation for further research is to expand the Modeling Instructional methods of teaching into different content areas, (i.e., reading and language arts) to explore academic achievement gains.

Detectability of Arctic methane sources at six sites performing continuous atmospheric measurements

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

Thonat, Thibaud; Saunois, Marielle; Bousquet, Philippe

Understanding the recent evolution of methane emissions in the Arctic is necessary to interpret the global methane cycle. Emissions are affected by significant uncertainties and are sensitive to climate change, leading to potential feedbacks. A polar version of the CHIMERE chemistry-transport model is used to simulate the evolution of tropospheric methane in the Arctic during 2012, including all known regional anthropogenic and natural sources, in particular freshwater emissions which are often overlooked in methane modelling. CHIMERE simulations are compared to atmospheric continuous observations at six measurement sites in the Arctic region. In winter, the Arctic is dominated by anthropogenic emissions;more » emissions from continental seepages and oceans, including from the East Siberian Arctic Shelf, can contribute significantly in more limited areas. In summer, emissions from wetland and freshwater sources dominate across the whole region. The model is able to reproduce the seasonality and synoptic variations of methane measured at the different sites. We find that all methane sources significantly affect the measurements at all stations at least at the synoptic scale, except for biomass burning. In particular, freshwater systems play a decisive part in summer, representing on average between 11 and 26 % of the simulated Arctic methane signal at the sites. This indicates the relevance of continuous observations to gain a mechanistic understanding of Arctic methane sources. Sensitivity tests reveal that the choice of the land-surface model used to prescribe wetland emissions can be critical in correctly representing methane mixing ratios. The closest agreement with the observations is reached when using the two wetland models which have emissions peaking in August–September, while all others reach their maximum in June–July. Such phasing provides an interesting constraint on wetland models which still have large uncertainties at present. Also testing different freshwater emission inventories leads to large differences in modelled methane. Attempts to include methane sinks (OH oxidation and soil uptake) reduced the model bias relative to observed atmospheric methane. Here, the study illustrates how multiple sources, having different spatiotemporal dynamics and magnitudes, jointly influence the overall Arctic methane budget, and highlights ways towards further improved assessments.« less

Detectability of Arctic methane sources at six sites performing continuous atmospheric measurements

DOE PAGES

Thonat, Thibaud; Saunois, Marielle; Bousquet, Philippe; ...

2017-07-11

Understanding the recent evolution of methane emissions in the Arctic is necessary to interpret the global methane cycle. Emissions are affected by significant uncertainties and are sensitive to climate change, leading to potential feedbacks. A polar version of the CHIMERE chemistry-transport model is used to simulate the evolution of tropospheric methane in the Arctic during 2012, including all known regional anthropogenic and natural sources, in particular freshwater emissions which are often overlooked in methane modelling. CHIMERE simulations are compared to atmospheric continuous observations at six measurement sites in the Arctic region. In winter, the Arctic is dominated by anthropogenic emissions;more » emissions from continental seepages and oceans, including from the East Siberian Arctic Shelf, can contribute significantly in more limited areas. In summer, emissions from wetland and freshwater sources dominate across the whole region. The model is able to reproduce the seasonality and synoptic variations of methane measured at the different sites. We find that all methane sources significantly affect the measurements at all stations at least at the synoptic scale, except for biomass burning. In particular, freshwater systems play a decisive part in summer, representing on average between 11 and 26 % of the simulated Arctic methane signal at the sites. This indicates the relevance of continuous observations to gain a mechanistic understanding of Arctic methane sources. Sensitivity tests reveal that the choice of the land-surface model used to prescribe wetland emissions can be critical in correctly representing methane mixing ratios. The closest agreement with the observations is reached when using the two wetland models which have emissions peaking in August–September, while all others reach their maximum in June–July. Such phasing provides an interesting constraint on wetland models which still have large uncertainties at present. Also testing different freshwater emission inventories leads to large differences in modelled methane. Attempts to include methane sinks (OH oxidation and soil uptake) reduced the model bias relative to observed atmospheric methane. Here, the study illustrates how multiple sources, having different spatiotemporal dynamics and magnitudes, jointly influence the overall Arctic methane budget, and highlights ways towards further improved assessments.« less

Detectability of Arctic methane sources at six sites performing continuous atmospheric measurements

NASA Astrophysics Data System (ADS)

Thonat, Thibaud; Saunois, Marielle; Bousquet, Philippe; Pison, Isabelle; Tan, Zeli; Zhuang, Qianlai; Crill, Patrick M.; Thornton, Brett F.; Bastviken, David; Dlugokencky, Ed J.; Zimov, Nikita; Laurila, Tuomas; Hatakka, Juha; Hermansen, Ove; Worthy, Doug E. J.

2017-07-01

Understanding the recent evolution of methane emissions in the Arctic is necessary to interpret the global methane cycle. Emissions are affected by significant uncertainties and are sensitive to climate change, leading to potential feedbacks. A polar version of the CHIMERE chemistry-transport model is used to simulate the evolution of tropospheric methane in the Arctic during 2012, including all known regional anthropogenic and natural sources, in particular freshwater emissions which are often overlooked in methane modelling. CHIMERE simulations are compared to atmospheric continuous observations at six measurement sites in the Arctic region. In winter, the Arctic is dominated by anthropogenic emissions; emissions from continental seepages and oceans, including from the East Siberian Arctic Shelf, can contribute significantly in more limited areas. In summer, emissions from wetland and freshwater sources dominate across the whole region. The model is able to reproduce the seasonality and synoptic variations of methane measured at the different sites. We find that all methane sources significantly affect the measurements at all stations at least at the synoptic scale, except for biomass burning. In particular, freshwater systems play a decisive part in summer, representing on average between 11 and 26 % of the simulated Arctic methane signal at the sites. This indicates the relevance of continuous observations to gain a mechanistic understanding of Arctic methane sources. Sensitivity tests reveal that the choice of the land-surface model used to prescribe wetland emissions can be critical in correctly representing methane mixing ratios. The closest agreement with the observations is reached when using the two wetland models which have emissions peaking in August-September, while all others reach their maximum in June-July. Such phasing provides an interesting constraint on wetland models which still have large uncertainties at present. Also testing different freshwater emission inventories leads to large differences in modelled methane. Attempts to include methane sinks (OH oxidation and soil uptake) reduced the model bias relative to observed atmospheric methane. The study illustrates how multiple sources, having different spatiotemporal dynamics and magnitudes, jointly influence the overall Arctic methane budget, and highlights ways towards further improved assessments.

Gender Differences in Hip Anatomy: Possible Implications for Injury Tolerance in Frontal Collisions

PubMed Central

Wang, Stewart C.; Brede, Chris; Lange, David; Poster, Craig S.; Lange, Aaron W.; Kohoyda-Inglis, Carla; Sochor, Mark R.; Ipaktchi, Kyros; Rowe, Stephen A.; Patel, Smita; Garton, Hugh J.

2004-01-01

Male occupants in frontal motor vehicle collisions have reduced tolerance for hip fractures than females in similar crashes. We studied 92 adult pelvic CT scans and found significant gender differences in bony pelvic geometry, including acetabular socket depth and femoral head width. Significant differences were also noted in the presentation angle of the acetabular socket to frontal loading. The observed differences provide biomechanical insight into why hip injury tolerance may differ with gender. These findings have implications for the future design of vehicle countermeasures as well as finite element models capable of more accurately predicting body tolerances to injury. PMID:15319131

[Models for biomass estimation of four shrub species planted in urban area of Xi'an city, Northwest China].

PubMed

Yao, Zheng-Yang; Liu, Jian-Jun

2014-01-01

Four common greening shrub species (i. e. Ligustrum quihoui, Buxus bodinieri, Berberis xinganensis and Buxus megistophylla) in Xi'an City were selected to develop the highest correlation and best-fit estimation models for the organ (branch, leaf and root) and total biomass against different independent variables. The results indicated that the organ and total biomass optimal models of the four shrubs were power functional model (CAR model) except for the leaf biomass model of B. megistophylla which was logarithmic functional model (VAR model). The independent variables included basal diameter, crown diameter, crown diameter multiplied by height, canopy area and canopy volume. B. megistophylla significantly differed from the other three shrub species in the independent variable selection, which were basal diameter and crown-related factors, respectively.

Population differences in the postcrania of modern South Africans and the implications for ancestry estimation.

PubMed

Liebenberg, Leandi; L'Abbé, Ericka N; Stull, Kyra E

2015-12-01

The cranium is widely recognized as the most important skeletal element to use when evaluating population differences and estimating ancestry. However, the cranium is not always intact or available for analysis, which emphasizes the need for postcranial alternatives. The purpose of this study was to quantify postcraniometric differences among South Africans that can be used to estimate ancestry. Thirty-nine standard measurements from 11 postcranial bones were collected from 360 modern black, white and coloured South Africans; the sex and ancestry distribution were equal. Group differences were explored with analysis of variance (ANOVA) and Tukey's honestly significant difference (HSD) test. Linear and flexible discriminant analysis (LDA and FDA, respectively) were conducted with bone models as well as numerous multivariate subsets to identify the model and method that yielded the highest correct classifications. Leave-one-out (LDA) and k-fold (k=10; FDA) cross-validation with equal priors were used for all models. ANOVA and Tukey's HSD results reveal statistically significant differences between at least two of the three groups for the majority of the variables, with varying degrees of group overlap. Bone models, which consisted of all measurements per bone, resulted in low accuracies that ranged from 46% to 63% (LDA) and 41% to 66% (FDA). In contrast, the multivariate subsets, which consisted of different variable combinations from all elements, achieved accuracies as high as 85% (LDA) and 87% (FDA). Thus, when using a multivariate approach, the postcranial skeleton can distinguish among three modern South African groups with high accuracy. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Effect of an oral healthcare protocol in nursing homes on care staffs' knowledge and attitude towards oral health care: a cluster-randomised controlled trial.

PubMed

Janssens, Barbara; De Visschere, Luc; van der Putten, Gert-Jan; de Lugt-Lustig, Kersti; Schols, Jos M G A; Vanobbergen, Jacques

2016-06-01

To explore the impact of a supervised implementation of an oral healthcare protocol, in addition to education, on nurses' and nurses' aides' oral health-related knowledge and attitude. A random sample of 12 nursing homes, accommodating a total of 120-150 residents, was obtained using stratified cluster sampling with replacement. The intervention included the implementation of an oral healthcare protocol and three different educational stages. One of the investigators supervised the implementation process, supported by a dental hygienist. A 34-item questionnaire was developed and validated to evaluate the knowledge and attitude of nurses and nurses' aides at baseline and 6 months after the start of the intervention. Linear mixed-model analyses were performed to explore differences in knowledge and attitude at 6 months after implementation. At baseline, no significant differences were observed between the intervention and the control group for both knowledge (p = 0.42) and attitude (p = 0.37). Six months after the start of the intervention, significant differences were found between the intervention and the control group for the variable knowledge in favour of the intervention group (p < 0.0001) but not for the variable attitude (p = 0.78). Out of the mixed model with attitude as the dependent variable, it can be concluded that age (p = 0.031), educational level (p = 0.009) and ward type (p = 0.014) have a significant effect. The mixed model with knowledge as the dependent variable resulted in a significant effect of the intervention (p = 0.001) and the educational level (p = 0.009). The supervised implementation of an oral healthcare protocol significantly increased the knowledge of nurses and nurses' aides. In contrast, no significant improvements could be demonstrated in attitude. © 2014 John Wiley & Sons A/S and The Gerodontology Association. Published by John Wiley & Sons Ltd.

Release of nitrogen compounds to the extracellular medium by three strains of Saccharomyces cerevisiae during induced autolysis in a model wine system.

PubMed

Martínez-Rodriguez, A J; Carrascosa, A V; Polo, M C

2001-08-15

To detect differences among three strains of Saccharomyces cerevisiae used in the manufacture of sparkling wines and to study the changes in nitrogen compounds during autolysis, a model wine system was used. Significant differences were observed between the mean values of the autolytic capacity of the three strains. The amount of nitrogen (total, protein, peptide and amino) present in the autolysates and the concentration of most free amino acids was significantly affected by the strain. These findings suggest that the strain of yeast used in the manufacture of sparkling wines can play an important role in the aging process and can affect final composition.

The Elephant in the Room: Spatial Heterogeneity and the Uncertainty of Measurements and Models

NASA Astrophysics Data System (ADS)

Alfieri, J. G.; Kustas, W. P.; Prueger, J. H.; Agam, N.; Neale, C. M. U.; Evett, S. R.

2014-12-01

Variations in surface conditions can significantly influence the exchange of heat and moisture between the land and atmosphere. As a result, measurements of surface fluxes using disparate methods not only may differ, they may fail to represent the surrounding landscape due to localized differences in surface conditions. To illustrate this, data collected over adjacent cotton fields during the Bushland Evapotranspiration and Agricultural Remote Sensing Experiment (BEAREX08) will be used. The evapotranspiration (ET) within each field was determined via lysimetry (LY), mass balance using neutron probe (NP) data, and a pair of eddy covariance (EC) systems. A comparison of the cumulative ET from each field showed that ET from LY was 20% to 25% greater than that derived from NP and 10% to 15% greater than those from EC. Additionally, the cumulative flux for the two fields collected using the same approach differed by 5% to 10%. These discrepancies can be explained, in large part, by the variations in vegetation density within the two fields. Not only were there substantial variations in the leaf area index (LAI) within the source areas of the different measurement systems - for example, the LAI within LY was, on average, 0.4 m2 m-2 greater than the LAI within the source area of NP - there were also significant differences in the LAI between the fields as a whole. The cumulative ET output by the remote sensing-based Two-Source Energy Balance (TSEB) model was also compared to the cumulative ET from each of the three measurement approaches. Depending on which measurement technique is used, the model either underestimated the moisture flux by approximately 5%, in the case of LY, or overestimated the flux by nearly 20%, in the case of NP. Comparison of the model output with EC data also indicated that the model overestimated ET, in this case, by approximately 10%. Clearly, the choice of which dataset is used to validate the model significantly effects the conclusions drawn regarding the model's accuracy and utility in estimating ET. The results of this study also underscores the limitations of each of these measurement techniques and the need to understand those limitations when using observational datasets to make general conclusions about field scale ET and validating model output.

Effect of rearing factors on the prevalence of floor eggs, cloacal cannibalism and feather pecking in commercial flocks of loose housed laying hens.

PubMed

Gunnarsson, S; Keeling, L J; Svedberg, J

1999-03-01

1. Effects of rearing conditions on behavioural problems were investigated in a cohort study of commercial flocks of laying hens housed in 2 different loose housing systems. The sample population was 120 385 laying hens from 59 flocks of various hybrids at 21 different farms. 2. Logistic regression modelling was used to test the effects of selected factors on floor eggs, cloacal cannibalism and feather pecking. In addition to early access to perches or litter, models included hybrid, stocking density, group size, housing system, age at delivery, identical housing system at the rearing farm and at the production farm and, in models for floor eggs and cloacal cannibalism, nest area per hen. Odds ratios were calculated from the results of the models to allow risk assessment. 3. No significant correlations were found between the prevalence of floor eggs, cloacal cannibalism and feather pecking. 4. Access to perches from not later than the 4th week of age decreased the prevalence of floor eggs during the period from start-of-lay until 35 weeks of age, odds ratio 0-30 (P<0-001). Furthermore, early access to perches decreased the prevalence of cloacal cannibalism during the production period, odds ratio 0-46 (P=0.03). 5. No other factor had a significant effect in these models. Although it was not significant, early access to litter had a non-significant tendency to reduce the prevalence of feather pecking.

Nature and kinetic analysis of carbon-carbon bond fragmentation reactions of cation radicals derived from SET-oxidation of lignin model compounds.

PubMed

Cho, Dae Won; Parthasarathi, Ramakrishnan; Pimentel, Adam S; Maestas, Gabriel D; Park, Hea Jung; Yoon, Ung Chan; Dunaway-Mariano, Debra; Gnanakaran, S; Langan, Paul; Mariano, Patrick S

2010-10-01

Features of the oxidative cleavage reactions of diastereomers of dimeric lignin model compounds, which are models of the major types of structural units found in the lignin backbone, were examined. Cation radicals of these substances were generated by using SET-sensitized photochemical and Ce(IV) and lignin peroxidase promoted oxidative processes, and the nature and kinetics of their C-C bond cleavage reactions were determined. The results show that significant differences exist between the rates of cation radical C1-C2 bond cleavage reactions of 1,2-diaryl-(β-1) and 1-aryl-2-aryloxy-(β-O-4) propan-1,3-diol structural units found in lignins. Specifically, under all conditions C1-C2 bond cleavage reactions of cation radicals of the β-1 models take place more rapidly than those of the β-O-4 counterparts. The results of DFT calculations on cation radicals of the model compounds show that the C1-C2 bond dissociation energies of the β-1 lignin model compounds are significantly lower than those of the β-O-4 models, providing clear evidence for the source of the rate differences.

Using expert opinion to evaluate a habitat effectiveness model for elk in western Oregon and Washington.

Treesearch

Richard S. Holthausen; Michael J. Wisdom; John Pierce; Daniel K. Edwards; Mary M. Rowland

1994-01-01

We used expert opinion to evaluate the predictive reliability of a habitat effectiveness model for elk in western Oregon and Washington. Twenty-five experts in elk ecology were asked to rate habitat quality for 16 example landscapes. Rankings and ratings of 21 experts were significantly correlated with model output. Expert opinion and model predictions differed for 4...

[Effects of Gukang on bone-source alkaline phosphatase (BALP) and insulin-like growth factor-1 (IGF-1) in serum of spaying rats].

PubMed

Chen, Yi-fan; Huang, Hong-xing; Li, Ying

2009-02-01

To investigate the effects of Gukang on bone-source alkaline phosphatase (BALP) and insulin-like growth factor 1 (IGF-1) in serum of spaying rats and the mechanism of curative effect of Gukang on osteoporosis. Sixty-eight 6-month-old SD rats were chosen and randomly divided into blank control group (22 rats with sham operation) and operation group (46 rats with spaying operation). Three months after operation, 10 rats were randomly chosen from each group and tested with bone mineral density in order to determine models of osteoporosis made. After modeling, operation group was divided into 3 sub-groups: operation model group, estrogen group and Gukang group, 12 rars in each group. Twelve rats remained in blank control group. Every group were treated through intragastric administration therapy (volume 10 ml/kg). Blank control group and operation model group were irrigated with distilled water,estrogen group with estrogen and Gukang group with Gukang. Three months after treatment, serum of all groups were collected and tested for E2, BALP and IGF-1 with ELISA. The concentration of serum E2, BALP in estrogen group and Gukang group were higher than operation model group, there were significant difference (P < 0.05), but no significant difference in serum E2 between estrogen group and Gukang group (P > 0.05). The concentration of serum IGF-1 in Gukang group was higher than operation model group and blank control group, there were significant difference (P < 0.05). Gukang can increase the level of E2, BALP and IGF-1 in serum of spaying rats. Thus, it can indirectly promote reproduction of osteoblasts, inhibit activity of osteoclasts and promote bone formation.

Stress response and communication in surgeons undergoing training in endoscopic management of major vessel hemorrhage: a mixed methods study.

PubMed

Jukes, Alistair K; Mascarenhas, Annika; Murphy, Jae; Stepan, Lia; Muñoz, Tamara N; Callejas, Claudio A; Valentine, Rowan; Wormald, P J; Psaltis, Alkis J

2017-06-01

Major vessel hemorrhage in endoscopic, endonasal skull-base surgery is a rare but potentially fatal event. Surgical simulation models have been developed to train surgeons in the techniques required to manage this complication. This mixed-methods study aims to quantify the stress responses the model induces, determine how realistic the experience is, and how it changes the confidence levels of surgeons in their ability to deal with major vascular injury in an endoscopic setting. Forty consultant surgeons and surgeons in training underwent training on an endoscopic sheep model of jugular vein and carotid artery injury. Pre-course and post-course questionnaires providing demographics, experience level, confidence, and realism scores were taken, based on a 5-point Likert scale. Objective markers of stress response including blood pressure, heart rate, and salivary alpha-amylase levels were measured. Mean "realism" score assessed posttraining showed the model to be perceived as highly realistic by the participants (score 4.02). Difference in participant self-rated pre-course and post-course confidence levels was significant (p < 0.0001): mean pre-course confidence level 1.66 (95% confidence interval [CI], 1.43 to 1.90); mean post-course confidence level 3.42 (95% CI, 3.19 to 3.65). Differences in subjects' heart rates (HRs) and mean arterial blood pressures (MAPs) were significant between injury models (p = 0.0008, p = 0.0387, respectively). No statistically significant difference in salivary alpha-amylase levels pretraining and posttraining was observed. Results from this study indicate that this highly realistic simulation model provides surgeons with an increased level of confidence in their ability to deal with the rare but potentially catastrophic event of major vessel injury in endoscopic skull-base surgery. © 2017 ARS-AAOA, LLC.

Are metastases from metastases clinical relevant? Computer modelling of cancer spread in a case of hepatocellular carcinoma.

PubMed

Bethge, Anja; Schumacher, Udo; Wree, Andreas; Wedemann, Gero

2012-01-01

Metastasis formation remains an enigmatic process and one of the main questions recently asked is whether metastases are able to generate further metastases. Different models have been proposed to answer this question; however, their clinical significance remains unclear. Therefore a computer model was developed that permits comparison of the different models quantitatively with clinical data and that additionally predicts the outcome of treatment interventions. The computer model is based on discrete events simulation approach. On the basis of a case from an untreated patient with hepatocellular carcinoma and its multiple metastases in the liver, it was evaluated whether metastases are able to metastasise and in particular if late disseminated tumour cells are still capable to form metastases. Additionally, the resection of the primary tumour was simulated. The simulation results were compared with clinical data. The simulation results reveal that the number of metastases varies significantly between scenarios where metastases metastasise and scenarios where they do not. In contrast, the total tumour mass is nearly unaffected by the two different modes of metastasis formation. Furthermore, the results provide evidence that metastasis formation is an early event and that late disseminated tumour cells are still capable of forming metastases. Simulations also allow estimating how the resection of the primary tumour delays the patient's death. The simulation results indicate that for this particular case of a hepatocellular carcinoma late metastases, i.e., metastases from metastases, are irrelevant in terms of total tumour mass. Hence metastases seeded from metastases are clinically irrelevant in our model system. Only the first metastases seeded from the primary tumour contribute significantly to the tumour burden and thus cause the patient's death.

An Integrated Experimental and Computational Approach for Characterizing the Kinetics and Mechanism of Triadimefon Racemization

EPA Science Inventory

Enantiomers of chiral molecules commonly exhibit different environmental fates, pharmacokinetics, and toxicities. Ignoring these differences can introduce significant uncertainty when modeling the physiological and environmental fate of chlral chemicals and evaluating their risk ...

Expected utility versus expected regret theory versions of decision curve analysis do generate different results when treatment effects are taken into account.

PubMed

Hozo, Iztok; Tsalatsanis, Athanasios; Djulbegovic, Benjamin

2018-02-01

Decision curve analysis (DCA) is a widely used method for evaluating diagnostic tests and predictive models. It was developed based on expected utility theory (EUT) and has been reformulated using expected regret theory (ERG). Under certain circumstances, these 2 formulations yield different results. Here we describe these situations and explain the variation. We compare the derivations of the EUT- and ERG-based formulations of DCA for a typical medical decision problem: "treat none," "treat all," or "use model" to guide treatment. We illustrate the differences between the 2 formulations when applied to the following clinical question: at which probability of death we should refer a terminally ill patient to hospice? Both DCA formulations yielded identical but mirrored results when treatment effects are ignored; they generated significantly different results otherwise. Treatment effect has a significant effect on the results derived by EUT DCA and less so on ERG DCA. The elicitation of specific values for disutilities affected the results even more significantly in the context of EUT DCA, whereas no such elicitation was required within the ERG framework. EUT and ERG DCA generate different results when treatment effects are taken into account. The magnitude of the difference depends on the effect of treatment and the disutilities associated with disease and treatment effects. This is important to realize as the current practice guidelines are uniformly based on EUT; the same recommendations can significantly differ if they are derived based on ERG framework. © 2016 The Authors. Journal of Evaluation in Clinical Practice Published by John Wiley & Sons Ltd.

Human bone marrow mesenchymal stem cells for retinal vascular injury.

PubMed

Wang, Jin-Da; An, Ying; Zhang, Jing-Shang; Wan, Xiu-Hua; Jonas, Jost B; Xu, Liang; Zhang, Wei

2017-09-01

To examine the potential of intravitreally implanted human bone marrow-derived mesenchymal stem cells (BMSCs) to affect vascular repair and the blood-retina barrier in mice and rats with oxygen-induced retinopathy, diabetic retinopathy or retinal ischaemia-reperfusion damage. Three study groups (oxygen-induced retinopathy group: 18 C57BL/6J mice; diabetic retinopathy group: 15 rats; retinal ischaemia-reperfusion model: 18 rats) received BMSCs injected intravitreally. Control groups (oxygen-induced retinopathy group: 12 C57BL/6J mice; diabetic retinopathy group: 15 rats; retinal ischaemia-reperfusion model: 18 rats) received an intravitreal injection of phosphate-buffered saline. We applied immunohistological techniques to measure retinal vascularization, spectroscopic measurements of intraretinally extravasated fluorescein-conjugated dextran to quantify the blood-retina barrier breakdown, and histomorphometry to assess retinal thickness and retinal ganglion cell count. In the oxygen-induced retinopathy model, the study group with intravitreally injected BMSCs as compared with the control group showed a significantly (p = 0.001) smaller area of retinal neovascularization. In the diabetic retinopathy model, study group and control group did not differ significantly in the amount of intraretinally extravasated dextran. In the retinal ischaemia-reperfusion model, on the 7th day after retina injury, the retina was significantly thicker in the study group than in the control group (p = 0.02), with no significant difference in the retinal ganglion cell count (p = 0.36). Intravitreally implanted human BMSCs were associated with a reduced retinal neovascularization in the oxygen-induced retinopathy model and with a potentially cell preserving effect in the retinal ischaemia-reperfusion model. Intravitreal BMSCs may be of potential interest for the therapy of retinal vascular disorders. © 2016 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

The Impact of Desert Dust Aerosol Radiative Forcing on Global and West African Precipitation

NASA Astrophysics Data System (ADS)

Jordan, A.; Zaitchik, B. F.; Gnanadesikan, A.; Dezfuli, A. K.

2015-12-01

Desert dust aerosols exert a radiative forcing on the atmosphere, influencing atmospheric temperature structure and modifying radiative fluxes at the top of the atmosphere (TOA) and surface. As dust aerosols perturb radiative fluxes, the atmosphere responds by altering both energy and moisture dynamics, with potentially significant impacts on regional and global precipitation. Global Climate Model (GCM) experiments designed to characterize these processes have yielded a wide range of results, owing to both the complex nature of the system and diverse differences across models. Most model results show a general decrease in global precipitation, but regional results vary. Here, we compare simulations from GFDL's CM2Mc GCM with multiple other model experiments from the literature in order to investigate mechanisms of radiative impact and reasons for GCM differences on a global and regional scale. We focus on West Africa, a region of high interannual rainfall variability that is a source of dust and that neighbors major Sahara Desert dust sources. As such, changes in West African climate due to radiative forcing of desert dust aerosol have serious implications for desertification feedbacks. Our CM2Mc results show net cooling of the planet at TOA and surface, net warming of the atmosphere, and significant increases in precipitation over West Africa during the summer rainy season. These results differ from some previous GCM studies, prompting comparative analysis of desert dust parameters across models. This presentation will offer quantitative analysis of differences in dust aerosol parameters, aerosol optical properties, and overall particle burden across GCMs, and will characterize the contribution of model differences to the uncertainty of forcing and climate response affecting West Africa.

White matter lesions and brain atrophy in systemic lupus erythematosus patients: correlation to cognitive dysfunction in a cohort of systemic lupus erythematosus patients using different definition models for neuropsychiatric systemic lupus erythematosus.

PubMed

Cannerfelt, B; Nystedt, J; Jönsen, A; Lätt, J; van Westen, D; Lilja, A; Bengtsson, A; Nilsson, P; Mårtensson, J; Sundgren, P C

2018-06-01

Aim The aim of this study was to evaluate the extent of white matter lesions, atrophy of the hippocampus and corpus callosum, and their correlation with cognitive dysfunction (CD), in patients diagnosed with systemic lupus erythematosus (SLE). Methods Seventy SLE patients and 25 healthy individuals (HIs) were included in the study. To evaluate the different SLE and neuropsychiatric SLE (NPSLE) definition schemes, patients were grouped both according to the American College of Rheumatology (ACR) definition, as well as the more stringent ACR-Systemic Lupus International Collaborating Clinics definition. Patients and HIs underwent a 3 Tesla brain MRI and a standardized neuropsychological test. MRI data were evaluated for number and volume of white matter lesions and atrophy of the hippocampus and corpus callosum. Differences between groups and subgroups were evaluated for significance. Number and volume of white matter lesions and atrophy of the hippocampus and corpus callosum were correlated to cognitive dysfunction. Results The total volume of white matter lesions was significantly larger in SLE patients compared to HIs ( p = 0.004). However, no significant differences were seen between the different SLE subgroups. Atrophy of the bilateral hippocampus was significantly more pronounced in patients with NPSLE compared to those with non-NPSLE (right: p = 0.010; left p = 0.023). Significant negative correlations between cognitive test scores on verbal memory and number and volume of white matter lesions were present. Conclusion SLE patients have a significantly larger volume of white matter lesions on MRI compared to HIs and the degree of white matter lesion volume correlates to cognitive dysfunction, specifically to verbal memory. No significant differences in the number or volume of white matter lesions were identified between subgroups of SLE patients regardless of the definition model used.

Sustainability and durability analysis of reinforced concrete structures

NASA Astrophysics Data System (ADS)

Horáková, A.; Broukalová, I.; Kohoutková, A.; Vašková, J.

2017-09-01

The article describes an assessment of reinforced concrete structures in terms of durability and sustainable development. There is a short summary of findings from the literature on evaluation methods for environmental impacts and also about corrosive influences acting on the reinforced concrete structure, about factors influencing the durability of these structures and mathematical models describing the corrosion impacts. Variant design of reinforced concrete structure and assessment of these variants in terms of durability and sustainability was performed. The analysed structure was a concrete ceiling structure of a parking house for cars. The variants differ in strength class of concrete and thickness of concrete slab. It was found that in terms of durability and sustainable development it is significantly preferable to use higher class of concrete. There are significant differences in results of concrete structures durability for different mathematical models of corrosive influences.

An Alternative Approach for Supportive Supervision and Skill Measurements of Health Workers for Integrated Management of Neonatal and Childhood Illnesses Program in 10 Districts of Haryana.

PubMed

Aggarwal, Arun K; Gupta, Rakesh; Das, Dhritiman; Dhakar, Anar S; Sharma, Gourav; Anand, Himani; Kaur, Kamalpreet; Sheoran, Kiran; Dalpath, Suresh; Khatri, Jaidev; Gupta, Madhu

2018-01-01

"Integrated Management of Neonatal and Childhood Illnesses" (IMNCI) needs regular supportive supervision (SS). The aim of this study was to find suitable SS model for implementing IMNCI. This was a prospective interventional study in 10 high-focus districts of Haryana. Two methods of SS were used: (a) visit to subcenters and home visits (model 1) and (b) organization of IMNCI clinics/camps at primary health center (PHC) and community health center (CHC) (model 2). Skill scores were measured at different time points. Routine IMNCI data from study block and randomly selected control block of each district were retrieved for 4 months before and after the training and supervision. Change in percentage mean skill score difference and percentage difference in median number of children were assessed in two areas. Mean skill scores increased significantly from 2.1 (pretest) to 7.0 (posttest 1). Supportive supervisory visits sustained and improved skill scores. While model 2 of SS could positively involve health system officials, model 1 was not well received. Outcome indicator in terms of number of children assessed showed a significant improvement in intervention areas. SS in IMNCI clinics/camps at PHC/CHC level and innovative skill scoring method is a promising approach.

The impact of winter and spring temperatures on temperate tree budburst dates: results from an experimental climate manipulation.

PubMed

Fu, Yongshuo H; Campioli, Matteo; Deckmyn, Gaby; Janssens, Ivan A

2012-01-01

Budburst phenology is a key driver of ecosystem structure and functioning, and it is sensitive to global change. Both cold winter temperatures (chilling) and spring warming (forcing) are important for budburst. Future climate warming is expected to have a contrasting effect on chilling and forcing, and subsequently to have a non-linear effect on budburst timing. To clarify the different effects of warming during chilling and forcing phases of budburst phenology in deciduous trees, (i) we conducted a temperature manipulation experiment, with separate winter and spring warming treatments on well irrigated and fertilized saplings of beech, birch and oak, and (ii) we analyzed the observations with five temperature-based budburst models (Thermal Time model, Parallel model, Sequential model, Alternating model, and Unified model). The results show that both winter warming and spring warming significantly advanced budburst date, with the combination of winter plus spring warming accelerating budburst most. As expected, all three species were more sensitive to spring warming than to winter warming. Although the different chilling requirement, the warming sensitivity was not significantly different among the studied species. Model evaluation showed that both one- and two- phase models (without and with chilling, respectively) are able to accurately predict budburst. For beech, the Sequential model reproduced budburst dates best. For oak and birch, both Sequential model and the Thermal Time model yielded good fit with the data but the latter was slightly better in case of high parameter uncertainty. However, for late-flushing species, the Sequential model is likely be the most appropriate to predict budburst data in a future warmer climate.

A Statistical Comparison of Coupled Thermosphere-Ionosphere Models

NASA Astrophysics Data System (ADS)

Liuzzo, L. R.

2014-12-01

The thermosphere-ionosphere system is a highly dynamic, non-linearly coupled interaction that fluctuates on a daily basis. Many models exist to attempt to quantify the relationship between the two atmospheric layers, and each approaches the problem differently. Because these models differ in the implementation of the equations that govern the dynamics of the thermosphere-ionosphere system, it is important to understand under which conditions each model performs best, and under which conditions each model may have limitations in accuracy. With this in consideration, this study examines the ability of two of the leading coupled thermosphere-ionosphere models in the community, TIE-GCM and GITM, to reproduce thermospheric and ionospheric quantities observed by the CHAMP satellite during times of differing geomagnetic activity. Neutral and electron densities are studied for three geomagnetic activity levels, ranging form high to minimal activity. Metrics used to quantify differences between the two models include root-mean-square error and prediction efficiency, and qualitative differences between a model and observed data is also considered. The metrics are separated into the high- mid- and low-latitude region to depict any latitudinal dependencies of the models during the various events. Despite solving for the same parameters, the models are shown to be highly dependent on the amount of activity level that occurs and can be significantly different from each other. In addition, in comparing previous statistical studies that use the models, a clear improvement is observed in the evolution of each model as thermospheric and ionosphericconstituents during the differing levels of activity are solved.

Results from ISOMIP+ and MISOMIP1, two interrelated marine ice sheet and ocean model intercomparison projects

NASA Astrophysics Data System (ADS)

Asay-Davis, X.; Galton-Fenzi, B.; Gwyther, D.; Jourdain, N.; Martin, D. F.; Nakayama, Y.; Seroussi, H. L.

2016-12-01

MISMIP+ (the third Marine Ice Sheet MIP), ISOMIP+ (the second Ice Shelf-Ocean MIP) and MISOMIP1 (the first Marine Ice Sheet-Ocean MIP) prescribe a set of idealized experiments for marine ice-sheet models, ocean models with ice-shelf cavities, and coupled ice sheet-ocean models, respectively. Here, we present results from ISOMIP+ and MISOMIP1 experiments using several ocean-only and coupled ice sheet-ocean models. Among the ocean models, we show that differences in model behavior are significant enough that similar results can only be achieved by tuning model parameters (the heat- and salt-transfer coefficients across the sub-ice-shelf boundary layer) for each model. This tuning is constrained by a desired mean melt rate in quasi-steady state under specified forcing conditions, akin to tuning the models to match observed melt rates. We compare the evolution of ocean temperature transects, melt rate, friction velocity and thermal driving between ocean models for the five ISOMIP+ experiments (Ocean0-4), which have prescribed ice-shelf topography. We find that melt patterns differ between models based on the relative importance of overturning strength and vertical mixing of temperature even when the models have been tuned to achieve similar melt rates near the grounding line. For the two MISOMIP1 experiments (IceOcean1 without dynamic calving and IceOcean2 with a simple calving parameterization), we compare temperature transects, melt rate, ice-shelf topography and grounded area across models and for several model configurations. Consistent with preliminary results from MISMIP+, we find that for a given coupled model, the use of a Coulomb-limited basal friction parameterization below grounded ice and the application of dynamic calving both significantly increase the rate of grounding-line retreat, whereas the rate of retreat appears to be less sensitive to the ice stress approximation (shallow-shelf approximation, higher-order, etc.). We show that models with similar mean melt rates, stress approximations and basal friction parameterizations produce markedly different rates of grounding-line retreat, and we investigate possible sources of these disparities (e.g. differences in coupling strategy or melt distribution).

People detection in crowded scenes using active contour models

NASA Astrophysics Data System (ADS)

Sidla, Oliver

2009-01-01

The detection of pedestrians in real-world scenes is a daunting task, especially in crowded situations. Our experience over the last years has shown that active shape models (ASM) can contribute significantly to a robust pedestrian detection system. The paper starts with an overview of shape model approaches, it then explains our approach which builds on top of Eigenshape models which have been trained using real-world data. These models are placed over candidate regions and matched to image gradients using a scoring function which integrates i) point distribution, ii) local gradient orientations iii) local image gradient strengths. A matching and shape model update process is iteratively applied in order to fit the flexible models to the local image content. The weights of the scoring function have a significant impact on the ASM performance. We analyze different settings of scoring weights for gradient magnitude, relative orientation differences, distance between model and gradient in an experiment which uses real-world data. Although for only one pedestrian model in an image computation time is low, the number of necessary processing cycles which is needed to track many people in crowded scenes can become the bottleneck in a real-time application. We describe the measures which have been taken in order to improve the speed of the ASM implementation and make it real-time capable.

Biomechanical Outcomes After Bio-enhanced Anterior Cruciate Ligament Repair and Anterior Cruciate Ligament Reconstruction Are Equal in a Porcine Model

PubMed Central

Vavken, Patrick; Fleming, Braden C.; Mastrangelo, Ashley N.; Machan, Jason T.; Murray, Martha M.

2011-01-01

Purpose The objective of this study was to compare the biomechanical outcomes of a new method of anterior cruciate ligament (ACL) treatment, bio-enhanced ACL repair, with ACL reconstruction in a large animal model. Methods Twenty-four skeletally immature pigs underwent unilateral ACL transection and were randomly allocated to receive bio-enhanced ACL repair with a collagen-platelet composite, allograft (bone–patellar tendon– bone) reconstruction, or no further treatment (n = 8 for each group). The structural properties and anteroposterior laxity of the experimental and contralateral ACL-intact knees were measured 15 weeks postoperatively. All dependent variables were normalized to those of the contralateral knee and compared by use of generalized linear mixed models. Results After 15 weeks, bio-enhanced ACL repair and ACL reconstruction produced superior biomechanical outcomes to ACL transection. However, there were no significant differences between bio-enhanced ACL repair and ACL reconstruction for maximum load (P = .4745), maximum displacement (P = .4217), or linear stiffness (P = .6327). There were no significant differences between the 2 surgical techniques in anteroposterior laxity at 30° (P = .7947), 60° (P = .6270), or 90° (P = .9008). Conclusions Bio-enhanced ACL repair produced biomechanical results that were not different from ACL reconstruction in a skeletally immature, large animal model, although the variability associated with both procedures was large. Both procedures produced significantly improved results over ACL transection, showing that both were effective in this model. Clinical Relevance Bio-enhanced ACL repair may 1 day provide an alternative treatment option for ACL injury. PMID:22261137

A comparison of major petroleum life cycle models | Science ...

EPA Pesticide Factsheets

Many organizations have attempted to develop an accurate well-to-pump life cycle model of petroleum products in order to inform decision makers of the consequences of its use. Our paper studies five of these models, demonstrating the differences in their predictions and attempting to evaluate their data quality. Carbon dioxide well-to-pump emissions for gasoline showed a variation of 35 %, and other pollutants such as ammonia and particulate matter varied up to 100 %. Differences in allocation do not appear to explain differences in predictions. Effects of these deviations on well-to-wheels passenger vehicle and truck transportation life cycle models may be minimal for effects such as global warming potential (6 % spread), but for respiratory effects of criteria pollutants (41 % spread) and other impact categories, they can be significant. A data quality assessment of the models’ documentation revealed real differences between models in temporal and geographic representativeness, completeness, as well as transparency. Stakeholders may need to consider carefully the tradeoffs inherent when selecting a model to conduct life cycle assessments for systems that make heavy use of petroleum products. This is a qualitative and quantitative comparison of petroleum LCA models intended for an expert audience interested in better understanding the data quality of existing petroleum life cycle models and the quantitative differences between these models.

Response of Debris-Covered and Clean-Ice Glaciers to Climate Change from Observations and Modeling

NASA Astrophysics Data System (ADS)

Rupper, S.; Maurer, J. M.; Schaefer, J. M.; Roe, G.; Huybers, K. M.

2017-12-01

Debris-covered glaciers form a significant percentage of the glacier area and volume in many mountainous regions of the world, and respond differently to climatic forcings as compared to clean-ice glaciers. In particular, debris-covered glaciers tend to downwaste with very little retreat, while clean-ice glaciers simultaneously thin and retreat. This difference has posed a significant challenge to quantifying glacier sensitivity to climate change, modeling glacier response to future climate change, and assessing the impacts of recent and future glacier changes on mountain environments and downstream populations. In this study, we evaluate observations of the geodetic mass balance and thinning profiles of 1000 glaciers across the Himalayas from 1975 to 2016. We use this large sampling of glacier changes over multiple decades to provide a robust statistical comparison of mass loss for clean-ice versus debris-covered glaciers over a period relevant to glacier dynamics. In addition, we force a glacier model with a series of climate change scenarios, and compare the modeled results to the observations. We essentially ask the question, "Are our theoretical expectations consistent with the observations?" Our observations show both clean-ice and debris-covered glaciers, regionally averaged, thinned in a similar pattern for the first 25-year observation period. For the more recent 15-year period, clean ice glaciers show significantly steepened thinning gradients across the surface, while debris-covered glaciers have continued to thin more uniformaly across the surface. Our preliminary model results generally agree with these observations, and suggest that both glacier types are expected to have a thinning phase followed by a retreat phase, but that the timing of the retreat phase is much later for debris-covered glaciers. Thus, these early results suggest these two glacier types are dynamically very similar, but are currently in different phases of response to recent climate change. This difference in phase of response will be carefully evaluated by integrating the modeling and observational components of this work. In addition, we will use this integrated framework to assess the expected impacts of differing glacier response on glacier-related resources in the Himalayas over the coming century.

SU-F-T-348: The Impact of Model Library Population On RapidPlan Based Dose-Volume Histograms (DVHs) Prediction for Rectal Cancer Patients Treated with Volumetric-Modulated Radiotherapy (VMAT)

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

Li, K; Zhou, L; Chen, Z

Purpose: RapidPlan uses a library consisting of expert plans from different patients to create a model that can predict achievable dose-volume histograms (DVHs) for new patients. The goal of this study is to investigate the impacts of model library population (plan numbers) on the DVH prediction for rectal cancer patients treated with volumetric-modulated radiotherapy (VMAT) Methods: Ninety clinically accepted rectal cancer patients’ VMAT plans were selected to establish 3 models, named as Model30, Model60 and Model90, with 30,60, and 90 plans in the model training. All plans had sufficient target coverage and bladder and femora sparings. Additional 10 patients weremore » enrolled to test the DVH prediction differences with these 3 models. The predicted DVHs from these 3 models were compared and analyzed. Results: Predicted V40 (Vx, percent of volume that received x Gy for the organs at risk) and Dmean (mean dose, cGy) of the bladder were 39.84±13.38 and 2029.4±141.6 for the Model30,37.52±16.00 and 2012.5±152.2 for the Model60, and 36.33±18.35 and 2066.5±174.3 for the Model90. Predicted V30 and Dmean of the left femur were 23.33±9.96 and 1443.3±114.5 for the Model30, 21.83±5.75 and 1436.6±61.9 for the Model60, and 20.31±4.6 and 1415.0±52.4 for the Model90.There were no significant differences among the 3 models for the bladder and left femur predictions. Predicted V40 and Dmean of the right femur were 19.86±10.00 and 1403.6±115.6 (Model30),18.97±6.19 and 1401.9±68.78 (Model60), and 21.08±7.82 and 1424.0±85.3 (Model90). Although a slight lower DVH prediction of the right femur was found on the Model60, the mean differences for V30 and mean dose were less than 2% and 1%, respectively. Conclusion: There were no significant differences among Model30, Model60 and Model90 for predicting DVHs on rectal patients treated with VMAT. The impact of plan numbers for model library might be limited for cancers with similar target shape.« less

Evaluation of accuracy of complete-arch multiple-unit abutment-level dental implant impressions using different impression and splinting materials.

PubMed

Buzayan, Muaiyed; Baig, Mirza Rustum; Yunus, Norsiah

2013-01-01

This in vitro study evaluated the accuracy of multiple-unit dental implant casts obtained from splinted or nonsplinted direct impression techniques using various splinting materials by comparing the casts to the reference models. The effect of two different impression materials on the accuracy of the implant casts was also evaluated for abutment-level impressions. A reference model with six internal-connection implant replicas placed in the completely edentulous mandibular arch and connected to multi-base abutments was fabricated from heat-curing acrylic resin. Forty impressions of the reference model were made, 20 each with polyether (PE) and polyvinylsiloxane (PVS) impression materials using the open tray technique. The PE and PVS groups were further subdivided into four subgroups of five each on the bases of splinting type: no splinting, bite registration PE, bite registration addition silicone, or autopolymerizing acrylic resin. The positional accuracy of the implant replica heads was measured on the poured casts using a coordinate measuring machine to assess linear differences in interimplant distances in all three axes. The collected data (linear and three-dimensional [3D] displacement values) were compared with the measurements calculated on the reference resin model and analyzed with nonparametric tests (Kruskal-Wallis and Mann-Whitney). No significant differences were found between the various splinting groups for both PE and PVS impression materials in terms of linear and 3D distortions. However, small but significant differences were found between the two impression materials (PVS, 91 μm; PE, 103 μm) in terms of 3D discrepancies, irrespective of the splinting technique employed. Casts obtained from both impression materials exhibited differences from the reference model. The impression material influenced impression inaccuracy more than the splinting material for multiple-unit abutment-level impressions.

On the dust load and rainfall relationship in South Asia: an analysis from CMIP5

NASA Astrophysics Data System (ADS)

Singh, Charu; Ganguly, Dilip; Dash, S. K.

2018-01-01

This study is aimed at examining the consistency of the relationship between load of dust and rainfall simulated by different climate models and its implication for the Indian summer monsoon system. Monthly mean outputs of 12 climate models, obtained from the archive of the Coupled Model Intercomparison Project phase 5 (CMIP5) for the period 1951-2004, are analyzed to investigate the relationship between dust and rainfall. Comparative analysis of the model simulated precipitation with the India Meteorological Department (IMD) gridded rainfall, CRU TS3.21 and GPCP version 2.2 data sets show significant differences between the spatial patterns of JJAS rainfall as well as annual cycle of rainfall simulated by various models and observations. Similarly, significant inter-model differences are also noted in the simulation of load of dust, nevertheless it is further noted that most of the CMIP5 models are able to capture the major dust sources across the study region. Although the scatter plot analysis and the lead-lag pattern correlation between the dust load and the rainfall show strong relationship between the dust load over distant sources and the rainfall in the South Asian region in individual models, the temporal scale of this association indicates large differences amongst the models. Our results caution that it would be pre-mature to draw any robust conclusions on the time scale of the relationship between dust and the rainfall in the South Asian region based on either CMIP5 results or limited number of previous studies. Hence, we would like to emphasize upon the fact that any conclusions drawn on the relationship between the dust load and the South Asian rainfall using model simulation is highly dependent on the degree of complexity incorporated in those models such as the representation of aerosol life cycle, their interaction with clouds, precipitation and other components of the climate system.

Anti-adhesive effect of poloxamer-based thermo-sensitive sol-gel in rabbit laminectomy model.

PubMed

Shin, Sung Joon; Lee, Jae Hyup; So, Jungwon; Min, Kyungdan

2016-11-01

Poloxamer-based thermo-sensitive sol-gel has been developed to reduce the incidence of postoperative scar formation at the laminectomy site. The purpose of this study was to evaluate the anti-adhesive effect of poloxamer based thermo-sensitive sol-gel compared to hyaluronate based solution after laminectomy, using a rabbit model. A thermo-sensitive anti-adhesive with a property of sol-gel transition was manufactured by a physical mixture of Poloxamer188/407, Chitosan and Gelatin. The viscosity in different temperatures was assessed. 72 adult New Zealand rabbits underwent lumbar laminectomy and were randomly divided into experimental (treated with the newly developed agent), positive (treated with hyaluronate based solution), and negative control groups. Each group was subdivided into 1 and 4-week subgroups. Gross and histological evaluations were performed to assess the extent of epidural adhesion. The experimental group showed significantly higher viscosity compared to the positive control group and showed a significant increase of viscosity as the temperature increased. Gross evaluation showed no statistically significant differences between the 1- and 4-week subgroups. However, histologic evaluation showed significant differences both in 1- and 4-week subgroups. Although the 4-week histologic results of the experimental and the positive control subgroups showed no significant difference, both subgroups revealed higher value compared to the negative control subgroup with regard to the ratio of adhesion less than 50 %. The new poloxamer based thermo-sensitive agent showed superior efficacy over the hyaluronate based agent at 1 week postoperatively. At 4 weeks postoperatively, there were no statistically significant differences between the two agents, although both showed efficacy over the sham group.

On the universality of the attribution-affect model of helping.

PubMed

Reisenzein, Rainer

2015-08-01

Although Pilati et al.'s (2014) findings question the strong quantitative universality of the attribution-affect model of helping, they are consistent with a weak form of quantitative universality, as well as with the qualitative universality of the theory. However, universality is put into question by previous studies revealing significant and sizeable between-study differences in the strength of the causal paths postulated by the theory. These differences may in part reflect differences in the type of helping situations studied. © 2015 International Union of Psychological Science.

Influence of standardization on the precision (reproducibility) of dental cast analysis with virtual 3-dimensional models.

PubMed

Hayashi, Kazuo; Chung, Onejune; Park, Seojung; Lee, Seung-Pyo; Sachdeva, Rohit C L; Mizoguchi, Itaru

2015-03-01

Virtual 3-dimensional (3D) models obtained by scanning of physical casts have become an alternative to conventional dental cast analysis in orthodontic treatment. If the precision (reproducibility) of virtual 3D model analysis can be further improved, digital orthodontics could be even more widely accepted. The purpose of this study was to clarify the influence of "standardization" of the target points for dental cast analysis using virtual 3D models. Physical plaster models were also measured to obtain additional information. Five sets of dental casts were used. The dental casts were scanned with R700 (3Shape, Copenhagen, Denmark) and REXCAN DS2 3D (Solutionix, Seoul, Korea) scanners. In this study, 3 system and software packages were used: SureSmile (OraMetrix, Richardson, Tex), Rapidform (Inus, Seoul, Korea), and I-DEAS (SDRC, Milford, Conn). Without standardization, the maximum differences were observed between the SureSmile software and the Rapidform software (0.39 mm ± 0.07). With standardization, the maximum differences were observed between the SureSmile software and measurements with a digital caliper (0.099 mm ± 0.01), and this difference was significantly greater (P <0.05) than the 2 other mean difference values. Furthermore, the results of this study showed that the mean differences "WITH" standardization were significantly lower than those "WITHOUT" standardization for all systems, software packages, or methods. The results showed that elimination of the influence of usability or habituation is important for improving the reproducibility of dental cast analysis. Copyright © 2015 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

Differences in knee adduction moment between healthy subjects and patients with osteoarthritis depend on the knee axis definition.

PubMed

Meireles, S; De Groote, F; Van Rossom, S; Verschueren, S; Jonkers, I

2017-03-01

This study, firstly, investigates the effect of using an anatomical versus a functional axis of rotation (FAR) on knee adduction moment (KAM) in healthy subjects and patients with knee osteoarthritis (KOA). Secondly, this study reports KAM for models with FAR calculated using weight-bearing and non-weight-bearing motion. Three musculoskeletal models were created using OpenSim with different knee axis of rotation (AR): transepicondylar axis (TEA); FAR calculated based on SARA algorithm using a weight-bearing motion (wFAR) and a non-weight-bearing motion (nwFAR). KAM were calculated during gait in fifty-nine subjects (n=20 healthy, n=16 early OA, n=23 established OA) for all models and groups. Significant differences between the three groups in the first peak KAM were found when TEA was used (p=0.038). However, these differences were no longer present when using FAR. In subjects with established OA, KAMs were significantly reduced when using nwFAR compared to TEA models but also compared to wFAR models. The presence of excessive KAM in subjects with established KOA showed to be dependent on the definition of the AR: anatomical versus functional. Therefore, caution should be accounted when comparing KAM in different studies on KOA patients. In patients with end-stage knee OA where increased passive knee laxity is likely to exist, the use of weight-bearing motions should be considered to avoid increased variability in the location and orientation of a FAR obtained from activities with only limited joint loading. Copyright © 2017 Elsevier B.V. All rights reserved.

Emotion perception and empathy: An individual differences test of relations.

PubMed

Olderbak, Sally; Wilhelm, Oliver

2017-10-01

Numerous theories posit a positive relation between perceiving emotion expressed in the face of a stranger (emotion perception) and feeling or cognitively understanding the emotion of that person (affective and cognitive empathy, respectively). However, when relating individual differences in emotion perception with individual differences in affective or cognitive empathy, effect sizes are contradictory, but often not significantly different from zero. Based on 4 studies (study ns range from 97 to 486 persons; n total = 958) that differ from one another on many design and sample characteristics, applying advanced modeling techniques to control for measurement error, we estimate relations between affective empathy, cognitive empathy, and emotion perception. Relations are tested separately for each of the 6 basic emotions (an emotion-specific model) as well as across all emotions (an emotion-general model). Reflecting the literature, effect sizes and statistical significance with an emotion-general model vary across the individual studies (rs range from -.001 to .24 for emotion perception with affective empathy and -.01 to .39 for emotion perception with cognitive empathy), with a meta-analysis of these results indicating emotion perception is weakly related with affective (r = .13, p = .003) and cognitive empathy (r = .13, p = .05). Relations are not strengthened in an emotion-specific model. We argue that the weak effect sizes and inconsistency across studies reflects a neglected distinction of measurement approach-specifically, empathy is assessed as typical behavior and emotion perception is assessed as maximal effort-and conclude with considerations regarding the measurement of each construct. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Sensitivity of NTCP parameter values against a change of dose calculation algorithm.

PubMed

Brink, Carsten; Berg, Martin; Nielsen, Morten

2007-09-01

Optimization of radiation treatment planning requires estimations of the normal tissue complication probability (NTCP). A number of models exist that estimate NTCP from a calculated dose distribution. Since different dose calculation algorithms use different approximations the dose distributions predicted for a given treatment will in general depend on the algorithm. The purpose of this work is to test whether the optimal NTCP parameter values change significantly when the dose calculation algorithm is changed. The treatment plans for 17 breast cancer patients have retrospectively been recalculated with a collapsed cone algorithm (CC) to compare the NTCP estimates for radiation pneumonitis with those obtained from the clinically used pencil beam algorithm (PB). For the PB calculations the NTCP parameters were taken from previously published values for three different models. For the CC calculations the parameters were fitted to give the same NTCP as for the PB calculations. This paper demonstrates that significant shifts of the NTCP parameter values are observed for three models, comparable in magnitude to the uncertainties of the published parameter values. Thus, it is important to quote the applied dose calculation algorithm when reporting estimates of NTCP parameters in order to ensure correct use of the models.

Sensitivity of NTCP parameter values against a change of dose calculation algorithm

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

Brink, Carsten; Berg, Martin; Nielsen, Morten

2007-09-15

Optimization of radiation treatment planning requires estimations of the normal tissue complication probability (NTCP). A number of models exist that estimate NTCP from a calculated dose distribution. Since different dose calculation algorithms use different approximations the dose distributions predicted for a given treatment will in general depend on the algorithm. The purpose of this work is to test whether the optimal NTCP parameter values change significantly when the dose calculation algorithm is changed. The treatment plans for 17 breast cancer patients have retrospectively been recalculated with a collapsed cone algorithm (CC) to compare the NTCP estimates for radiation pneumonitis withmore » those obtained from the clinically used pencil beam algorithm (PB). For the PB calculations the NTCP parameters were taken from previously published values for three different models. For the CC calculations the parameters were fitted to give the same NTCP as for the PB calculations. This paper demonstrates that significant shifts of the NTCP parameter values are observed for three models, comparable in magnitude to the uncertainties of the published parameter values. Thus, it is important to quote the applied dose calculation algorithm when reporting estimates of NTCP parameters in order to ensure correct use of the models.« less

What’s the good of education on our overall quality of life? A simultaneous equation model of education and life satisfaction for Australia

PubMed Central

Powdthavee, Nattavudh; Lekfuangfu, Warn N.; Wooden, Mark

2017-01-01

Many economists and educators favour public support for education on the premise that education improves the overall quality of life of citizens. However, little is known about the different pathways through which education shapes people’s satisfaction with life overall. One reason for this is because previous studies have traditionally analysed the effect of education on life satisfaction using single-equation models that ignore interrelationships between different theoretical explanatory variables. In order to advance our understanding of how education may be related to overall quality of life, the current study estimates a structural equation model using nationally representative data for Australia to obtain the direct and indirect associations between education and life satisfaction through five different adult outcomes: income, employment, marriage, children, and health. Although we find the estimated direct (or net) effect of education on life satisfaction to be negative and statistically significant in Australia, the total indirect effect is positive, sizeable and statistically significant for both men and women. This implies that misleading conclusions regarding the influence of education on life satisfaction might be obtained if only single-equation models were used in the analysis. PMID:28713668

Attachment change processes in the early years of marriage.

PubMed

Davila, J; Karney, B R; Bradbury, T N

1999-05-01

The authors examined 4 models of attachment change: a contextual model, a social-cognitive model, an individual-difference model, and a diathesis-stress model. Models were examined in a sample of newlyweds over the first 2 years of marriage, using growth curve analyses. Reciprocal processes, whereby attachment representations and interpersonal life circumstances affect one another over time, also were studied. On average, newlyweds became more secure over time. However, there was significant within-subject variability on attachment change that was predicted by intra- and interpersonal factors. Attachment representations changed in response to contextual, social-cognitive, and individual-difference factors. Reciprocal processes between attachment representations and marital variables emerged, suggesting that these factors influence one another in an ongoing way.

Comparison of statistical models for writer verification

NASA Astrophysics Data System (ADS)

Srihari, Sargur; Ball, Gregory R.

2009-01-01

A novel statistical model for determining whether a pair of documents, a known and a questioned, were written by the same individual is proposed. The goal of this formulation is to learn the specific uniqueness of style in a particular author's writing, given the known document. Since there are often insufficient samples to extrapolate a generalized model of an writer's handwriting based solely on the document, we instead generalize over the differences between the author and a large population of known different writers. This is in contrast to an earlier model proposed whereby probability distributions were a priori without learning. We show the performance of the model along with a comparison in performance to the non-learning, older model, which shows significant improvement.

Typologies in Comparative Vocational Education: Existing Models and a New Approach

ERIC Educational Resources Information Center

Pilz, Matthias

2016-01-01

The ways in which vocational education and training (VET) systems are structured vary significantly from country to country, both because different countries have different objectives for their VET systems and because VET is differently embedded within the education and labour market systems of any individual country. International research in…

Large differences in regional precipitation change between a first and second 2 K of global warming

PubMed Central

Good, Peter; Booth, Ben B. B.; Chadwick, Robin; Hawkins, Ed; Jonko, Alexandra; Lowe, Jason A.

2016-01-01

For adaptation and mitigation planning, stakeholders need reliable information about regional precipitation changes under different emissions scenarios and for different time periods. A significant amount of current planning effort assumes that each K of global warming produces roughly the same regional climate change. Here using 25 climate models, we compare precipitation responses with three 2 K intervals of global ensemble mean warming: a fast and a slower route to a first 2 K above pre-industrial levels, and the end-of-century difference between high-emission and mitigation scenarios. We show that, although the two routes to a first 2 K give very similar precipitation changes, a second 2 K produces quite a different response. In particular, the balance of physical mechanisms responsible for climate model uncertainty is different for a first and a second 2 K of warming. The results are consistent with a significant influence from nonlinear physical mechanisms, but aerosol and land-use effects may be important regionally. PMID:27922014

Evaluation of the influence of white grape seed extracts as copigment sources on the anthocyanin extraction from grape skins previously classified by near infrared hyperspectral tools.

PubMed

Nogales-Bueno, Julio; Baca-Bocanegra, Berta; Jara-Palacios, María José; Hernández-Hierro, José Miguel; Heredia, Francisco José

2017-04-15

Hyperspectral imaging has been used to classify red grapes (Vitis vinifera L.) according to their predicted extractable total anthocyanin content (i.e. extractable total anthocyanin content determined by a hyperspectral method). Low, medium and high levels of predicted extractable total anthocyanin content were established. Then, grape skins were split into three parts and each part was macerated into a different model wine solution for a three-day period. Wine model solutions were made up with different concentration of copigments coming from white grape seeds. Aqueous supernatants were analyzed by HPLC-DAD and extractable anthocyanin contents were obtained. Principal component analyses and analyses of variance were carried out with the aim of studying trends related to the extractable anthocyanin contents. Significant differences were found among grapes with different levels of predicted extractable anthocyanin contents. Moreover, no significant differences were found on the extractable anthocyanin contents using different copigment concentrations in grape skin macerations. Copyright © 2016 Elsevier Ltd. All rights reserved.

Comparison of different radioactive agents for the detection of renovascular hypertension with captopril in a rat model

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

McAfee, J.G.; Kopecky, R.T.; Thomas, F.D.

1988-04-01

In Goldblatt hypertension in rats produced by implanting a silver clip on the left renal artery, captopril induces a greater difference in the 1-min uptake of diethylenetriaminepentaacetic acid (DTPA) between the two kidneys than in baseline uptakes, similar to the experiences in unilateral renovascular hypertension in man. The combination of captopril and furosemide induces an even greater difference in renal uptakes than with captopril alone in this rat model. In paired experiments, DTPA complexes were used as a standard to compare the differences in renal uptake between the two kidneys after captopril-furosemide with other existing and potential renal radiodiagnostic agents.more » No statistically significant difference was found between DTPA, glucoheptonate, dimercaptosuccinic acid, aminated dextran, or lysozyme. However, the differences in renal uptake were significantly less with hippuran than with DTPA. Furosemide and captopril caused delayed renal retention of hippuran after one minute. This response appeared to be due to non-specific volume depletion because it occurred in both clipped and unclipped kidneys.« less

Fringe Benefits Available to Supported Employment Participants.

ERIC Educational Resources Information Center

West, Michael; And Others

1990-01-01

Examined fringe benefits available to individuals in supported employment. Found that 64 percent of supported employees received fringe benefits. Found significant differences in availability of particular benefits across employment models. Medical-health insurance coverage was available more frequently to persons in individual placement models.…

Delivery of primary health care to persons who are socio-economically disadvantaged: does the organizational delivery model matter?

PubMed Central

2013-01-01

Background As health systems evolve, it is essential to evaluate their impact on the delivery of health services to socially disadvantaged populations. We evaluated the delivery of primary health services for different socio-economic groups and assessed the performance of different organizational models in terms of equality of health care delivery in Ontario, Canada. Methods Cross sectional study of 5,361 patients receiving care from primary care practices using Capitation, Salaried or Fee-For-Service remuneration models. We assessed self-reported health status of patients, visit duration, number of visits per year, quality of health service delivery, and quality of health promotion. We used multi-level regressions to study service delivery across socio-economic groups and within each delivery model. Identified disparities were further analysed using a t-test to determine the impact of service delivery model on equity. Results Low income individuals were more likely to be women, unemployed, recent immigrants, and in poorer health. These individuals were overrepresented in the Salaried model, reported more visits/year across all models, and tended to report longer visits in the Salaried model. Measures of primary care services generally did not differ significantly between low and higher income/education individuals; when they did, the difference favoured better service delivery for at-risk groups. At-risk patients in the Salaried model were somewhat more likely to report health promotion activities than patients from Capitation and Fee-For-Service models. At-risk patients from Capitation models reported a smaller increase in the number of additional clinic visits/year than Fee-For-Service and Salaried models. At-risk patients reported better first contact accessibility than their non-at-risk counterparts in the Fee-For-Service model only. Conclusions Primary care service measures did not differ significantly across socio-economic status or primary care delivery models. In Ontario, capitation-based remuneration is age and sex adjusted only. Patients of low socio-economic status had fewer additional visits compared to those with high socio-economic status under the Capitation model. This raises the concern that Capitation may not support the provision of additional care for more vulnerable groups. Regions undertaking primary care model reforms need to consider the potential impact of the changes on the more vulnerable populations. PMID:24341530

Implementation and Operational Research: Strengthening HIV Test Access and Treatment Uptake Study (Project STATUS): A Randomized Trial of HIV Testing and Counseling Interventions.

PubMed

McNaghten, A D; Schilsky Mneimneh, Allison; Farirai, Thato; Wamai, Nafuna; Ntiro, Marylad; Sabatier, Jennifer; Makhunga-Ramfolo, Nondumiso; Mwanasalli, Salli; Awor, Anna; Moore, Jan

2015-12-01

To determine which of 3 HIV testing and counseling (HTC) models in outpatient departments (OPDs) increases HIV testing and entry of newly identified HIV-infected patients into care. Randomized trial of HTC interventions. Thirty-six OPDs in South Africa, Tanzania, and Uganda were randomly assigned to 3 different HTC models: (A) health care providers referred eligible patients (aged 18-49, not tested in the past year, not known HIV positive) to on-site voluntary counseling and testing for HTC offered and provided by voluntary counseling and testing counselors after clinical consultation; (B) health care providers offered and provided HTC to eligible patients during clinical consultation; and (C) nurse or lay counselors offered and provided HTC to eligible patients before clinical consultation. Data were collected from October 2011 to September 2012. We describe testing eligibility and acceptance, HIV prevalence, and referral and entry into care. Chi-square analyses were conducted to examine differences by model. Of 79,910 patients, 45% were age eligible and 16,099 (45%) age eligibles were tested. Ten percent tested HIV positive. Significant differences were found in percent tested by model. The proportion of age eligible patients tested by Project STATUS was highest for model C (54.1%, 95% confidence interval [CI]: 42.4 to 65.9), followed by model A (41.7%, 95% CI: 30.7 to 52.8), and then model B (33.9%, 95% CI: 25.7 to 42.1). Of the 1596 newly identified HIV positive patients, 94% were referred to care (96.1% in model A, 94.7% in model B, and 94.9% in model C), and 58% entered on-site care (74.4% in model A, 54.8% in model B, and 55.6% in model C) with no significant differences in referrals or care entry by model. Model C resulted in the highest proportion of all age-eligible patients receiving a test. Although 94% of STATUS patients with a positive test result were referred to care, only 58% entered care. We found no differences in patients entering care by HTC model. Routine HTC in OPDs is acceptable to patients and effective for identifying HIV-infected persons, but additional efforts are needed to increase entry to care.

Delivery of primary health care to persons who are socio-economically disadvantaged: does the organizational delivery model matter?

PubMed

Dahrouge, Simone; Hogg, William; Ward, Natalie; Tuna, Meltem; Devlin, Rose Anne; Kristjansson, Elizabeth; Tugwell, Peter; Pottie, Kevin

2013-12-17

As health systems evolve, it is essential to evaluate their impact on the delivery of health services to socially disadvantaged populations. We evaluated the delivery of primary health services for different socio-economic groups and assessed the performance of different organizational models in terms of equality of health care delivery in Ontario, Canada. Cross sectional study of 5,361 patients receiving care from primary care practices using Capitation, Salaried or Fee-For-Service remuneration models. We assessed self-reported health status of patients, visit duration, number of visits per year, quality of health service delivery, and quality of health promotion. We used multi-level regressions to study service delivery across socio-economic groups and within each delivery model. Identified disparities were further analysed using a t-test to determine the impact of service delivery model on equity. Low income individuals were more likely to be women, unemployed, recent immigrants, and in poorer health. These individuals were overrepresented in the Salaried model, reported more visits/year across all models, and tended to report longer visits in the Salaried model. Measures of primary care services generally did not differ significantly between low and higher income/education individuals; when they did, the difference favoured better service delivery for at-risk groups. At-risk patients in the Salaried model were somewhat more likely to report health promotion activities than patients from Capitation and Fee-For-Service models. At-risk patients from Capitation models reported a smaller increase in the number of additional clinic visits/year than Fee-For-Service and Salaried models. At-risk patients reported better first contact accessibility than their non-at-risk counterparts in the Fee-For-Service model only. Primary care service measures did not differ significantly across socio-economic status or primary care delivery models. In Ontario, capitation-based remuneration is age and sex adjusted only. Patients of low socio-economic status had fewer additional visits compared to those with high socio-economic status under the Capitation model. This raises the concern that Capitation may not support the provision of additional care for more vulnerable groups. Regions undertaking primary care model reforms need to consider the potential impact of the changes on the more vulnerable populations.

Dynamical Core in Atmospheric Model Does Matter in the Simulation of Arctic Climate

NASA Astrophysics Data System (ADS)

Jun, Sang-Yoon; Choi, Suk-Jin; Kim, Baek-Min

2018-03-01

Climate models using different dynamical cores can simulate significantly different winter Arctic climates even if equipped with virtually the same physics schemes. Current climate simulated by the global climate model using cubed-sphere grid with spectral element method (SE core) exhibited significantly warmer Arctic surface air temperature compared to that using latitude-longitude grid with finite volume method core. Compared to the finite volume method core, SE core simulated additional adiabatic warming in the Arctic lower atmosphere, and this was consistent with the eddy-forced secondary circulation. Downward longwave radiation further enhanced Arctic near-surface warming with a higher surface air temperature of about 1.9 K. Furthermore, in the atmospheric response to the reduced sea ice conditions with the same physical settings, only the SE core showed a robust cooling response over North America. We emphasize that special attention is needed in selecting the dynamical core of climate models in the simulation of the Arctic climate and associated teleconnection patterns.

A genetically engineered human Kunitz protease inhibitor with increased kallikrein inhibition in an ovine model of cardiopulmonary bypass.

PubMed

Ohri, S K; Parratt, R; White, T; Becket, J; Brannan, J J; Hunt, B J; Taylor, K M

2001-05-01

A recombinant human serine protease inhibitor known as Kunitz protease inhibitor (KPI) wild type has functional similarities to the bovine Kunitz inhibitor, aprotinin, and had shown a potential to reduce bleeding in an ovine model of cardiopulmonary bypass (CPB). The aim of this study was to assess KPI-185, a modification of KPI-wild type that differs from KPI-wild type in two amino acid residues and which enhances anti-kallikrein activity in a further double-blind, randomized study in an ovine model of CPB, and to compare with our previous study of KPI-wild type and aprotinin in the same ovine model. Post-operative drain losses and subjective assessment of wound 'dryness' showed no significant differences between KPI-185 and KPI-wild type, despite the significant enhancement of kallikrein inhibition using KPI-185 seen in serial kallikrein inhibition assays. These preliminary findings support the hypothesis that kallikrein inhibition is not the major mechanism by which Kunitz inhibitors such as aprotinin reduce perioperative bleeding.

Parent-Adolescent Relationship Qualities, Internal Working Models, and Styles as Predictors of Adolescents’ Observed Interactions with Friends

PubMed Central

Shomaker, Lauren B.; Furman, Wyndol

2010-01-01

This study examined how current parent-adolescent relationship qualities and adolescents’ representations of relationships with parents were related to friendship interactions in 200 adolescent-close friend dyads. Adolescents and friends were observed discussing problems during a series of structured tasks. Negative interactions with mothers were significantly related to adolescents’ greater conflict with friends, poorer focus on tasks, and poorer communication skills. Security of working models (as assessed by interview) was significantly associated with qualities of friendship interactions, whereas security of attachment styles (as assessed by questionnaire) was not. More dismissing (vs. secure) working models were associated with poorer focus on problem discussions and weaker communication skills with friends, even after accounting for gender differences and current parent-adolescent relationship qualities. We discuss possible mechanisms for the observed links between dimensions of parent-adolescent relationships and friendships. We also consider methodological and conceptual differences between working model and style measures of attachment representations. PMID:20174459

Characteristics of organic soil in black spruce forests: Implications for the application of land surface and ecosystem models in cold regions

USGS Publications Warehouse

Yi, S.; Manies, K.; Harden, J.; McGuire, A.D.

2009-01-01

Soil organic layers (OL) play an important role in landatmosphere exchanges of water, energy and carbon in cold environments. The proper implementation of OL in land surface and ecosystem models is important for predicting dynamic responses to climate warming. Based on the analysis of OL samples of black spruce (Picea mariana), we recommend that implementation of OL for cold regions modeling: (1) use three general organic horizon types (live, fibrous, and amorphous) to represent vertical soil heterogeneity; (2) implement dynamics of OL over the course of disturbance, as there are significant differences of OL thickness between young and mature stands; and (3) use two broad drainage classes to characterize spatial heterogeneity, as there are significant differences in OL thickness between dry and wet sites. Implementation of these suggestions into models has the potential to substantially improve how OL dynamics influence variability in surface temperature and soil moisture in cold regions. Copyright 2009 by the American Geophys.ical Union.

Clot retraction affects the extent of ultrasound-enhanced thrombolysis in an ex vivo porcine thrombosis model

PubMed Central

Sutton, Jonathan T.; Ivancevich, Nikolas M.; Perrin, Stephen R.; Vela, Deborah C.; Holland, Christy K.

2013-01-01

Using an FDA-approved contrast agent (Definity®) and thrombolytic drug (rt-PA), we investigated ultrasound-enhanced thrombolysis in two whole-blood clot models. Porcine venous blood was collected from donor hogs and coagulated in two different materials. This method produced clots with differing compositional properties, as determined by routine scanning electron microscopy and histology. Clots were deployed in an ex vivo porcine thrombolysis model, while an intermittent ultrasound scheme previously developed to maximize stable cavitation was applied and acoustic emissions were detected. Exposure of clots to 3.15 μg/mL rt-PA promoted lysis in both clot models, compared to exposure to plasma alone. However, in the presence of rt-PA, Definity®, and ultrasound, only unretracted clots experienced significant enhancement of thrombolysis compared to treatment with rt-PA. In these clots, microscopy studies revealed loose erythrocyte aggregates, a significantly less extensive fibrin network, and a higher porosity, which may facilitate increase penetration of thrombolytics by cavitation. PMID:23453629

Adult attachment, perceived social support, cultural orientation, and depressive symptoms: A moderated mediation model.

PubMed

Zhu, Wenzhen; Wang, Chiachih Dc; Chong, Chu Chian

2016-11-01

In the current study, we tested a moderated mediation model in which cultural orientation moderated the mediation model of adult attachment-perceived social support-depressive symptoms, using 2 comparable cross-cultural samples of college students recruited from China and the U.S. (n = 363 for each group). Results indicated that perceived social support mediated the effect of attachment anxiety on depressive symptoms as well as the link between attachment avoidance and depression in both samples. Moderated mediation analyses using PROCESS revealed that interdependent self-construal significantly buffered the indirect effect of attachment avoidance (via perceived social support) on depressive symptoms. The findings indicated significant differences in the mediation models between the U.S. and China groups and interdependent self-construal accounted for the between-country differences. Limitations, implications of the findings, and future research directions are discussed from the perspectives of cross-cultural variation of adult attachment functioning. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

The biomechanical significance of pulley on binocular vision.

PubMed

Guo, Hongmei; Gao, Zhipeng; Chen, Weiyi

2016-12-28

Pulleys have been reported as the functional origins of the rectus extraocular muscles (EOMs). However, biomechanical significance of pulleys on binocular vision has not been reported. Three eye movement models, i.e., non-pulley model, passive-pulley model, and active-pulley model, are used to simulate the horizontal movement of the eyes from the primary position to the left direction in the range of 1°-30°. The resultant forces of six EOMs along both orthogonal directions (i.e., the x-axis and y-axis defined in this paper) in the horizontal plane are calculated using the three models. The resultant force along the y-axis of the left eye for non-pulley model are significantly larger than that of the other two pulley models. The difference of the force, between the left eye and the right eye in non-pulley model, is larger than those in the other two pulley models along x-axis and y-axis. The pulley models present more biomechanical advantage on the horizontally binocular vision than the non-pulley model. Combining with the previous imaging evidences of pulleys, the results show that pulley model coincides well with the real physiological conditions.

Persistent Intraluminal Pressure After Endovascular Stent Grafting for Type B Aortic Dissection.

PubMed

Qing, K-X; Chan, Y-C; Ting, A C W; Cheng, S W K

2016-05-01

Despite technically successful thoracic endovascular stent graft repair (TEVAR) in patients with Stanford Type B aortic dissection (TBAD), long-term follow up studies have shown that the false lumen may continue to dilate. The aim of this study was to analyze the possible mechanisms leading to such changes from a hemodynamic perspective. Twenty-eight ex vivo fresh porcine TBAD models (Mo A: 10; Model B: 12; Model C: 6) were established to simulate three clinical situations: Model A with patent false lumen (pre-TEVAR); Model B with distal re-entry only (post-TEVAR), and Model C with thrombus filling in the false lumen and a distal re-entry (chronic stage of post-TEVAR). Synchronous pressure waveforms were taken from both the true and the false lumen. True lumen and false lumen pressure differences were calculated for each model as four indices: systolic index (SI), diastolic index (DI), mean pressure index (MPI) and area under curve index (AUCI). These indices were compared between the three models. False lumen pressure and corresponding pressure-accumulating effects were significantly higher in Model A than in Model C: SI (99.9% vs. 189.4%; p < .001); MPI and AUCI (99.5% vs. 128.2%; 99.5% vs. 128%; p < .001). The SI, MPI, and AUCI were significantly higher in Model B compared with Model C. The differences between the four indices were not significant between Model A and B. The false lumen area under curve (AUC) in Model C was merely lowered by 20% compared with its true lumen (67.5 mmHg vs. 85.2 mmHg). The false lumen pressure remained unchanged in the non-thrombosed segment with patent blood flow after the primary entry tear sealed. Intraluminal pressure reduction in the thrombosed false lumen was significant. However, nearly 80% of the pressure remained in the thrombosed false lumen. If this high intra-thrombus pressure persists, it may contribute to delayed aneurysmal formation after endovascular treatment. Copyright © 2016 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

The effect of call libraries and acoustic filters on the identification of bat echolocation.

PubMed

Clement, Matthew J; Murray, Kevin L; Solick, Donald I; Gruver, Jeffrey C

2014-09-01

Quantitative methods for species identification are commonly used in acoustic surveys for animals. While various identification models have been studied extensively, there has been little study of methods for selecting calls prior to modeling or methods for validating results after modeling. We obtained two call libraries with a combined 1556 pulse sequences from 11 North American bat species. We used four acoustic filters to automatically select and quantify bat calls from the combined library. For each filter, we trained a species identification model (a quadratic discriminant function analysis) and compared the classification ability of the models. In a separate analysis, we trained a classification model using just one call library. We then compared a conventional model assessment that used the training library against an alternative approach that used the second library. We found that filters differed in the share of known pulse sequences that were selected (68 to 96%), the share of non-bat noises that were excluded (37 to 100%), their measurement of various pulse parameters, and their overall correct classification rate (41% to 85%). Although the top two filters did not differ significantly in overall correct classification rate (85% and 83%), rates differed significantly for some bat species. In our assessment of call libraries, overall correct classification rates were significantly lower (15% to 23% lower) when tested on the second call library instead of the training library. Well-designed filters obviated the need for subjective and time-consuming manual selection of pulses. Accordingly, researchers should carefully design and test filters and include adequate descriptions in publications. Our results also indicate that it may not be possible to extend inferences about model accuracy beyond the training library. If so, the accuracy of acoustic-only surveys may be lower than commonly reported, which could affect ecological understanding or management decisions based on acoustic surveys.

The effect of call libraries and acoustic filters on the identification of bat echolocation

PubMed Central

Clement, Matthew J; Murray, Kevin L; Solick, Donald I; Gruver, Jeffrey C

2014-01-01

Quantitative methods for species identification are commonly used in acoustic surveys for animals. While various identification models have been studied extensively, there has been little study of methods for selecting calls prior to modeling or methods for validating results after modeling. We obtained two call libraries with a combined 1556 pulse sequences from 11 North American bat species. We used four acoustic filters to automatically select and quantify bat calls from the combined library. For each filter, we trained a species identification model (a quadratic discriminant function analysis) and compared the classification ability of the models. In a separate analysis, we trained a classification model using just one call library. We then compared a conventional model assessment that used the training library against an alternative approach that used the second library. We found that filters differed in the share of known pulse sequences that were selected (68 to 96%), the share of non-bat noises that were excluded (37 to 100%), their measurement of various pulse parameters, and their overall correct classification rate (41% to 85%). Although the top two filters did not differ significantly in overall correct classification rate (85% and 83%), rates differed significantly for some bat species. In our assessment of call libraries, overall correct classification rates were significantly lower (15% to 23% lower) when tested on the second call library instead of the training library. Well-designed filters obviated the need for subjective and time-consuming manual selection of pulses. Accordingly, researchers should carefully design and test filters and include adequate descriptions in publications. Our results also indicate that it may not be possible to extend inferences about model accuracy beyond the training library. If so, the accuracy of acoustic-only surveys may be lower than commonly reported, which could affect ecological understanding or management decisions based on acoustic surveys. PMID:25535563

A framework for establishing predictive relationships between specific bacterial 16S rRNA sequence abundances and biotransformation rates.

PubMed

Helbling, Damian E; Johnson, David R; Lee, Tae Kwon; Scheidegger, Andreas; Fenner, Kathrin

2015-03-01

The rates at which wastewater treatment plant (WWTP) microbial communities biotransform specific substrates can differ by orders of magnitude among WWTP communities. Differences in taxonomic compositions among WWTP communities may predict differences in the rates of some types of biotransformations. In this work, we present a novel framework for establishing predictive relationships between specific bacterial 16S rRNA sequence abundances and biotransformation rates. We selected ten WWTPs with substantial variation in their environmental and operational metrics and measured the in situ ammonia biotransformation rate constants in nine of them. We isolated total RNA from samples from each WWTP and analyzed 16S rRNA sequence reads. We then developed multivariate models between the measured abundances of specific bacterial 16S rRNA sequence reads and the ammonia biotransformation rate constants. We constructed model scenarios that systematically explored the effects of model regularization, model linearity and non-linearity, and aggregation of 16S rRNA sequences into operational taxonomic units (OTUs) as a function of sequence dissimilarity threshold (SDT). A large percentage (greater than 80%) of model scenarios resulted in well-performing and significant models at intermediate SDTs of 0.13-0.14 and 0.26. The 16S rRNA sequences consistently selected into the well-performing and significant models at those SDTs were classified as Nitrosomonas and Nitrospira groups. We then extend the framework by applying it to the biotransformation rate constants of ten micropollutants measured in batch reactors seeded with the ten WWTP communities. We identified phylogenetic groups that were robustly selected into all well-performing and significant models constructed with biotransformation rates of isoproturon, propachlor, ranitidine, and venlafaxine. These phylogenetic groups can be used as predictive biomarkers of WWTP microbial community activity towards these specific micropollutants. This work is an important step towards developing tools to predict biotransformation rates in WWTPs based on taxonomic composition. Copyright © 2014 Elsevier Ltd. All rights reserved.

The effect of call libraries and acoustic filters on the identification of bat echolocation

USGS Publications Warehouse

Clement, Matthew; Murray, Kevin L; Solick, Donald I; Gruver, Jeffrey C

2014-01-01

Quantitative methods for species identification are commonly used in acoustic surveys for animals. While various identification models have been studied extensively, there has been little study of methods for selecting calls prior to modeling or methods for validating results after modeling. We obtained two call libraries with a combined 1556 pulse sequences from 11 North American bat species. We used four acoustic filters to automatically select and quantify bat calls from the combined library. For each filter, we trained a species identification model (a quadratic discriminant function analysis) and compared the classification ability of the models. In a separate analysis, we trained a classification model using just one call library. We then compared a conventional model assessment that used the training library against an alternative approach that used the second library. We found that filters differed in the share of known pulse sequences that were selected (68 to 96%), the share of non-bat noises that were excluded (37 to 100%), their measurement of various pulse parameters, and their overall correct classification rate (41% to 85%). Although the top two filters did not differ significantly in overall correct classification rate (85% and 83%), rates differed significantly for some bat species. In our assessment of call libraries, overall correct classification rates were significantly lower (15% to 23% lower) when tested on the second call library instead of the training library. Well-designed filters obviated the need for subjective and time-consuming manual selection of pulses. Accordingly, researchers should carefully design and test filters and include adequate descriptions in publications. Our results also indicate that it may not be possible to extend inferences about model accuracy beyond the training library. If so, the accuracy of acoustic-only surveys may be lower than commonly reported, which could affect ecological understanding or management decisions based on acoustic surveys.

Enhancing prediction power of chemometric models through manipulation of the fed spectrophotometric data: A comparative study

NASA Astrophysics Data System (ADS)

Saad, Ahmed S.; Hamdy, Abdallah M.; Salama, Fathy M.; Abdelkawy, Mohamed

2016-10-01

Effect of data manipulation in preprocessing step proceeding construction of chemometric models was assessed. The same set of UV spectral data was used for construction of PLS and PCR models directly and after mathematically manipulation as per well known first and second derivatives of the absorption spectra, ratio spectra and first and second derivatives of the ratio spectra spectrophotometric methods, meanwhile the optimal working wavelength ranges were carefully selected for each model and the models were constructed. Unexpectedly, number of latent variables used for models' construction varied among the different methods. The prediction power of the different models was compared using a validation set of 8 mixtures prepared as per the multilevel multifactor design and results were statistically compared using two-way ANOVA test. Root mean squares error of prediction (RMSEP) was used for further comparison of the predictability among different constructed models. Although no significant difference was found between results obtained using Partial Least Squares (PLS) and Principal Component Regression (PCR) models, however, discrepancies among results was found to be attributed to the variation in the discrimination power of adopted spectrophotometric methods on spectral data.

Reducing treatment of coppersmelting slag: Thermodynamic analysis of impurities behavior

NASA Astrophysics Data System (ADS)

Komkov, Alexey; Kamkin, Rostislav

2011-01-01

A thermodynamic mathematical model, describing behavior of Pb, Zn, and As during reducing slag cleaning in the Vanyukov furnace has been developed. Using a developed model, the influence of different factors, such as temperature, oxygen partial pressure, the ratio of the formed phases on the behavior of impurities, was analyzed. It was found that arsenic can significantly move to the bottom phase, and zinc can be significantly vaporized under conditions in the Vanyukov furnace.

Effects of blood-activating and stasis-removing drugs combined with VEGF gene transfer on angiogenesis in ischemic necrosis of the femoral head.

PubMed

Li, Jun-Hui; Wu, Ya-Ling; Ye, Jian-Hong; Ning, Ya-Gong; Yu, Hai-Ying; Peng, Zhong-Jie; Luan, Xiao-Wen

2009-09-01

To observe the promoting effects of blood-activating and stasis-removing Chinese drugs combined with vascular endothelial growth factor (VEGF) gene transfer on angiogenesis in ischemic necrosis of the femoral head. Forty Japanese giant-ear rabbits were randomly divided into a control group, a model group, a Chinese drug group, a gene group, and a combined group. After 8 weeks of treatment, the rate of VEGF positive cell expression in the synovium of the femoral head was measured using the immunohistochemical method, and the number of blood vessels in the femoral head was measured by digital subtraction angiography. The rate of VEGF positive cell expression in the model group was significantly lower than that in the Chinese drug group (P < 0.05) and very significantly lower than those in other groups (P < 0.01); but in the combined group it was significantly higher than in the Chinese drug group (P < 0.05). The differences in the number of blood vessels in area A between the model group and other groups were not statistically significant. However, in area B, the number of blood vessels significantly increased in the control group, the gene group and the combined group as compared with the model group (P < 0.05), and in the combined group the number of blood vessels was significantly more than in the gene group (P < 0.05); but in the Chinese drug group it was not significantly different than the model group (P > 0.05). Either the blood-activating and stasis-removing Chinese drugs or VEGF gene transfer can promote the angiogenesis and building of collateral circulation for femoral head ischemic necrosis, and the combined therapy with Chinese drugs or VEGF gene transfer may show a better therapeutic effect. The present study provides an experimental basis for clinical application of the combined therapy with the blood-activating and stasis-removing Chinese drugs and VEGF gene transfer.

[Effects of electroacupuncture at "Jiaji" (EX-B 2) on myocardial apoptosis and the expression of Bcl-2 and Bax in rats with ischemia-reperfusion injury].

PubMed

Kong, Su-Ping; Zhang, Xin; Tan, Qi-Wen

2013-06-01

To explore the protective mechanism of acupuncture on myocardial ischemia-reperfusion injury. Fifty Wistar rats were randomly divided into a sham-operation group, a model group, a Jiaji group , a Neiguan group and a Yanglingquan group, 10 rats in each group. The model of myocardial ischemia-reperfusion injury was duplicated by ligating the left anterior descending coronary artery (LADCA) in the later four groups, and the LADCA was not ligated in the sham-operation group. The rats in the treatment groups were treated with electroacupuncture at "Jiaji" (EX-B 2), "Neiguan" (PC 6) and "Yanglingquan" (GB 34) on both sides, respectively, once a day for 7 days. No interventions were produced in the sham-operation group and model group. Myocardial apoptosis were examined by the TUNEL method. The expressions of Bcl-2 and Bax proteins were measured by immunohistochemical method. Apoptosis index(AI) was significantly lower in the Jiaji group, Neiguan group and sham-operation group compared with model group (P < 0.01). Compared with the sham-operation group, AI were significantly increased in other groups (all P < 0.01). There was no significant difference in AI between Jiaji and Neiguan group (P > 0.05). Compared with the model group, the expression of Bcl-2 was significantly increased and Bax protein was significantly decreased in Jiaji group and Neiguan group (both P < 0.01). The expressions of Bcl-2 and Bax proteins were significantly increased in other groups compared with the sham-operation group (all P < 0.01). There was no significant difference in the expression of Bcl-2 and Bax proteins between Jiaji and Neiguan group (P > 0.05). Electroacupuncture at both Jiaji (EX-B 2) and Neiguan (PC 6) has protective effects on myocardial ischemia-reperfusion injury, and the mechanism is closely related to inhibiting myocardial apoptosis by adjusting the expression of Bcl-2 and Bax.

Modeling users, context and devices for ambient assisted living environments.

PubMed

Castillejo, Eduardo; Almeida, Aitor; López-de-Ipiña, Diego; Chen, Liming

2014-03-17

The participation of users within AAL environments is increasing thanks to the capabilities of the current wearable devices. Furthermore, the significance of considering user's preferences, context conditions and device's capabilities help smart environments to personalize services and resources for them. Being aware of different characteristics of the entities participating in these situations is vital for reaching the main goals of the corresponding systems efficiently. To collect different information from these entities, it is necessary to design several formal models which help designers to organize and give some meaning to the gathered data. In this paper, we analyze several literature solutions for modeling users, context and devices considering different approaches in the Ambient Assisted Living domain. Besides, we remark different ongoing standardization works in this area. We also discuss the used techniques, modeled characteristics and the advantages and drawbacks of each approach to finally draw several conclusions about the reviewed works.

Modeling Users, Context and Devices for Ambient Assisted Living Environments

PubMed Central

Castillejo, Eduardo; Almeida, Aitor; López-de-Ipiña, Diego; Chen, Liming

2014-01-01

The participation of users within AAL environments is increasing thanks to the capabilities of the current wearable devices. Furthermore, the significance of considering user's preferences, context conditions and device's capabilities help smart environments to personalize services and resources for them. Being aware of different characteristics of the entities participating in these situations is vital for reaching the main goals of the corresponding systems efficiently. To collect different information from these entities, it is necessary to design several formal models which help designers to organize and give some meaning to the gathered data. In this paper, we analyze several literature solutions for modeling users, context and devices considering different approaches in the Ambient Assisted Living domain. Besides, we remark different ongoing standardization works in this area. We also discuss the used techniques, modeled characteristics and the advantages and drawbacks of each approach to finally draw several conclusions about the reviewed works. PMID:24643006

The influence of lip form on incisal display with lips in repose on the esthetic preferences of dentists and lay people.

PubMed

Kim, Jee; Topolski, Richard; Dickinson, Douglas; Ramos, Van

2017-09-01

Information is lacking for viewer preferences for incisal display with lips in repose. The purpose of this online survey was to establish measurement parameters to classify and define a lip form and to evaluate the influence of lip form on dentists' and laypersons' preferences for the amount of incisal display with lips in repose. Computer-generated male and female models were created using 3 different lip forms each, straight, moderate, and high. Three images of these models (frontal full face, zoomed-in frontal around the mouth, and oblique zoomed-in image of the mouth) were arranged in an interactive survey that was disseminated on the Websites Facebook, Instagram, DentalTown and by word-of-mouth. Respondents manipulated the incisal display of all 3 images in unison, using a slide bar, and the resulting incisal display was measured in millimeters and served as the primary dependent measure. Survey demographic data were obtained from an online survey site. Data were assessed for skewness, kurtosis, and outliers and analyzed with 5-way ANOVA: 2 sex levels for model, 2 levels for sex of respondent, 3 levels for lip height, 3 levels for occupation, and 5 levels of ethnicity, with multiple comparisons corrected with Bonferroni adjustments and post hoc comparisons performed using the Scheffé test (α=.05 for all comparisons). A total of 1039 individuals consented to the study. A final sample size of 687 respondents was obtained after excluding 352 who failed to complete the survey. The results indicated that lip form affected the esthetic perception of incisal display significantly (P<.001), with a preference for a greater amount of incisal display corresponding with increasing lip forms. Sex of the model was also significant, with greater incisal display being preferred for female faces. A significant difference was found for respondents' ethnicity, with African Americans generally preferring smaller incisal displays than other ethnic groups. No other main effects were found to be statistically significant. Only 2 interactions were shown to be statistically significant. Post hoc tests examining the interaction between lip form and sex of model showed a preference for greater incisal displays for female faces with high lip forms. A 3-way interaction was observed between lip form, sex of respondent, and occupation. Significant differences were identified for the 3 different lip forms for both sexes of models. As the lip form changed from straight to moderate to high, there was a preference for increased incisal display. Incisal display preferences for male and female models were the same for all respondents, except for the high lip form, for which a greater amount of incisal display was preferred for the female model. Sex and occupation of respondent failed to produce main effects. Respondents' ethnicity was shown to be statistically significant, with African Americans generally preferring shorter incisal displays. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

OEDGE modeling of plasma contamination efficiency of Ar puffing from different divertor locations in EAST

NASA Astrophysics Data System (ADS)

Pengfei, ZHANG; Ling, ZHANG; Zhenwei, WU; Zong, XU; Wei, GAO; Liang, WANG; Qingquan, YANG; Jichan, XU; Jianbin, LIU; Hao, QU; Yong, LIU; Juan, HUANG; Chengrui, WU; Yumei, HOU; Zhao, JIN; J, D. ELDER; Houyang, GUO

2018-04-01

Modeling with OEDGE was carried out to assess the initial and long-term plasma contamination efficiency of Ar puffing from different divertor locations, i.e. the inner divertor, the outer divertor and the dome, in the EAST superconducting tokamak for typical ohmic plasma conditions. It was found that the initial Ar contamination efficiency is dependent on the local plasma conditions at the different gas puff locations. However, it quickly approaches a similar steady state value for Ar recycling efficiency >0.9. OEDGE modeling shows that the final equilibrium Ar contamination efficiency is significantly lower for the more closed lower divertor than that for the upper divertor.

Weight reduction does not induce an undesirable decrease in muscle mass, muscle strength, or physical performance in men with obesity: a pilot study.

PubMed

Kim, Bokun; Tsujimoto, Takehiko; So, Rina; Zhao, Xiaoguang; Oh, Sechang; Tanaka, Kiyoji

2017-12-31

To date, there have been no reports on whether weight reduction causes decreases in muscle mass, muscle strength, or physical performance that could lead to health problems. Thus, in this pilot study, we investigated the appropriateness of the changes in muscle mass, muscle strength and physical performance after weight reduction. Obese men who completed a weight reduction program to decrease and maintain a body mass index (BMI) of less than 25 kg/m2 for one year were recruited for the study. One year after the completion of a weight reduction program, the participants' muscle mass, muscle strength, and physical performance were compared with those in a reference group composed of individuals whose BMI was less than 25 kg/m2. Whole-body scanning was performed using dual-energy X-ray absorptiometry to analyze muscle mass. Handgrip strength and knee extensor strength were measured to evaluate arm and leg muscle strength, respectively. For physical performance, a jump test was employed. The results showed that the biceps, triceps, subscapular, and suprailiac areas of professional fashion models were significantly thinner than those of women in general (p<.001), and that their waist size was also significantly smaller (p<.001). However, hip circumference showed no significant difference. Body mass index, waist-to-hip ratio, and body fat (%) in professional fashion models were significantly lower than those in women in general (p<.001), while the body density in professional fashion models was significantly greater (p<0.001). Weight reduction participants showed an average reduction in body weight of -16.47%. Normalized arm muscle mass and handgrip strength were significantly greater in the weight reduction group than in the reference group; however, no significant differences were detected between the two groups with respect to the other variables. After one year, there were no significant differences between the two groups. ©2017 The Korean Society for Exercise Nutrition

Comparison of Different Attitude Correction Models for ZY-3 Satellite Imagery

NASA Astrophysics Data System (ADS)

Song, Wenping; Liu, Shijie; Tong, Xiaohua; Niu, Changling; Ye, Zhen; Zhang, Han; Jin, Yanmin

2018-04-01

ZY-3 satellite, launched in 2012, is the first civilian high resolution stereo mapping satellite of China. This paper analyzed the positioning errors of ZY-3 satellite imagery and conducted compensation for geo-position accuracy improvement using different correction models, including attitude quaternion correction, attitude angle offset correction, and attitude angle linear correction. The experimental results revealed that there exist systematic errors with ZY-3 attitude observations and the positioning accuracy can be improved after attitude correction with aid of ground controls. There is no significant difference between the results of attitude quaternion correction method and the attitude angle correction method. However, the attitude angle offset correction model produced steady improvement than the linear correction model when limited ground control points are available for single scene.

Disseminated flake graphite and amorphous graphite deposit types. An analysis using grade and tonnage models

USGS Publications Warehouse

Sutphin, David M.; Bliss, James D.

1990-01-01

On the basis of differences derived from genetic, descriptive, and grade-tonnage data, graphite deposits are classified here into three deposit types: disseminated flake, amorphous (microcrystalline), or graphite veins. Descriptive models have been constructed for each of these deposit types, and grade-tonnage models are constructed for disseminated flake and amorphous deposit types. Grade and tonnage data are used also to construct grade-tonnage models that assist in predicting the size and grade of undiscovered graphite deposits. The median tonnage and carbon grade of disseminated flake deposits are 240 000 tonnes and 9% carbon and for amorphous deposits, 130 000 tonnes and 40% carbon. The differences in grade between disseminated flake and amorphous deposit types are statistically significant, whereas the differences in amount of contained carbon are not.

PconsD: ultra rapid, accurate model quality assessment for protein structure prediction.

PubMed

Skwark, Marcin J; Elofsson, Arne

2013-07-15

Clustering methods are often needed for accurately assessing the quality of modeled protein structures. Recent blind evaluation of quality assessment methods in CASP10 showed that there is little difference between many different methods as far as ranking models and selecting best model are concerned. When comparing many models, the computational cost of the model comparison can become significant. Here, we present PconsD, a fast, stream-computing method for distance-driven model quality assessment that runs on consumer hardware. PconsD is at least one order of magnitude faster than other methods of comparable accuracy. The source code for PconsD is freely available at http://d.pcons.net/. Supplementary benchmarking data are also available there. arne@bioinfo.se Supplementary data are available at Bioinformatics online.

Modeling the mechanical properties of liver fibrosis in rats.

PubMed

Zhu, Ying; Chen, Xin; Zhang, Xinyu; Chen, Siping; Shen, Yuanyuan; Song, Liang

2016-06-14

The progression of liver fibrosis changes the biomechanical properties of liver tissue. This study characterized and compared different liver fibrosis stages in rats in terms of viscoelasticity. Three viscoelastic models, the Voigt, Maxwell, and Zener models, were applied to experimental data from rheometer tests and then the elasticity and viscosity were estimated for each fibrosis stage. The study found that both elasticity and viscosity are correlated with the various stages of liver fibrosis. The study revealed that the Zener model is the optimal model for describing the mechanical properties of each fibrosis stage, but there is no significant difference between the Zener and Voigt models in their performance on liver fibrosis staging. Therefore the Voigt model can still be effectively used for liver fibrosis grading. Copyright © 2016 Elsevier Ltd. All rights reserved.

Verification by Remote Sensing of an Oil Slick Movement Prediction Model

NASA Technical Reports Server (NTRS)

Klemas, V. (Principal Investigator); Davis, G.; Wang, H.

1975-01-01

The author has identified the following significant results. LANDSAT, aircraft, ships, and air-dropped current drogues were deployed to determine current circulation and to track oil slick movement on four different dates in Delaware Bay. Results were used to verify a predictive model for oil slick movement and dispersion. The model predicts the behavior of oil slicks given their size, location, tidal stage (current), weather (wind), and nature of crude. Both LANDSAT satellites provided valuable data on gross circulation patterns and convergent coastal fronts which by capturing oil slicks significantly influence their movement and dispersion.

Integrating remote sensing and GIS for prediction of winter wheat (Triticum aestivum) protein contents in Linfen (Shanxi), China.

PubMed

Feng, Mei-chen; Xiao, Lu-jie; Zhang, Mei-jun; Yang, Wu-de; Ding, Guang-wei

2014-01-01

In this study, relationships between normalized difference vegetation index (NDVI) and plant (winter wheat) nitrogen content (PNC) and between PNC and grain protein content (GPC) were investigated using multi-temporal moderate-resolution imaging spectroradiometer (MODIS) data at the different stages of winter wheat in Linfen (Shanxi, P. R. China). The anticipating model for GPC of winter wheat was also established by the approach of NDVI at the different stages of winter wheat. The results showed that the spectrum models of PNC passed F test. The NDVI4.14 regression effect of PNC model of irrigated winter wheat was the best, and that in dry land was NDVI4.30. The PNC of irrigated and dry land winter wheat were significantly (P<0.01) and positively correlated to GPC. Both of protein spectral anticipating model of irrigated and dry land winter wheat passed a significance test (P<0.01). Multiple anticipating models (MAM) were established by NDVI from two periods of irrigated and dry land winter wheat and PNC to link GPC anticipating model. The coefficient of determination R(2) (R) of MAM was greater than that of the other two single-factor models. The relative root mean square error (RRMSE) and relative error (RE) of MAM were lower than those of the other two single-factor models. Therefore, test effects of multiple proteins anticipating model were better than those of single-factor models. The application of multiple anticipating models for predication of protein content (PC) of irrigated and dry land winter wheat was more accurate and reliable. The regionalization analysis of GPC was performed using inverse distance weighted function of GIS, which is likely to provide the scientific basis for the reasonable winter wheat planting in Linfen city, China.

Integrating Remote Sensing and GIS for Prediction of Winter Wheat (Triticum aestivum) Protein Contents in Linfen (Shanxi), China

PubMed Central

Feng, Mei-chen; Xiao, Lu-jie; Zhang, Mei-jun; Yang, Wu-de; Ding, Guang-wei

2014-01-01

In this study, relationships between normalized difference vegetation index (NDVI) and plant (winter wheat) nitrogen content (PNC) and between PNC and grain protein content (GPC) were investigated using multi-temporal moderate-resolution imaging spectroradiometer (MODIS) data at the different stages of winter wheat in Linfen (Shanxi, P. R. China). The anticipating model for GPC of winter wheat was also established by the approach of NDVI at the different stages of winter wheat. The results showed that the spectrum models of PNC passed F test. The NDVI4.14 regression effect of PNC model of irrigated winter wheat was the best, and that in dry land was NDVI4.30. The PNC of irrigated and dry land winter wheat were significantly (P<0.01) and positively correlated to GPC. Both of protein spectral anticipating model of irrigated and dry land winter wheat passed a significance test (P<0.01). Multiple anticipating models (MAM) were established by NDVI from two periods of irrigated and dry land winter wheat and PNC to link GPC anticipating model. The coefficient of determination R2 (R) of MAM was greater than that of the other two single-factor models. The relative root mean square error (RRMSE) and relative error (RE) of MAM were lower than those of the other two single-factor models. Therefore, test effects of multiple proteins anticipating model were better than those of single-factor models. The application of multiple anticipating models for predication of protein content (PC) of irrigated and dry land winter wheat was more accurate and reliable. The regionalization analysis of GPC was performed using inverse distance weighted function of GIS, which is likely to provide the scientific basis for the reasonable winter wheat planting in Linfen city, China. PMID:24404124

Hydrological and biogeochemical response of the Mediterranean Sea to freshwater flow changes for the end of the 21st century.

PubMed

Macias, Diego; Stips, Adolf; Garcia-Gorriz, Elisa; Dosio, Alessandro

2018-01-01

We evaluate the changes on the hydrological (temperature and salinity) and biogeochemical (phytoplankton biomass) characteristics of the Mediterranean Sea induced by freshwater flow modifications under two different scenarios for the end of the 21st century. An ensemble of four regional climate model realizations using different global circulation models at the boundary and different emission scenarios are used to force a single ocean model for the Mediterranean Sea. Freshwater flow is modified according to the simulated changes in the precipitation rates for the different rivers' catchment regions. To isolate the effect resulting from a change in freshwater flow, model results are evaluated against a 'baseline' simulation realized assuming a constant inflow equivalent to climatologic values. Our model results indicate that sea surface salinity could be significantly altered by freshwater flow modification in specific regions and that the affected area and the sign of the anomaly are highly dependent on the used climate model and emission scenario. Sea surface temperature and phytoplankton biomass, on the contrary, show no coherent spatial pattern but a rather widespread scattered response. We found in open-water regions a significant negative relationship between sea surface temperature anomalies and phytoplankton biomass anomalies. This indicates that freshwater flow modification could alter the vertical stability of the water column throughout the Mediterranean Sea, by changing the strength of vertical mixing and consequently upper water fertilization. In coastal regions, however, the correlation between sea temperature anomalies and phytoplankton biomass is positive, indicating a larger importance of the physiological control of growth rates by temperature.

Time-lag effects of global vegetation responses to climate change.

PubMed

Wu, Donghai; Zhao, Xiang; Liang, Shunlin; Zhou, Tao; Huang, Kaicheng; Tang, Bijian; Zhao, Wenqian

2015-09-01

Climate conditions significantly affect vegetation growth in terrestrial ecosystems. Due to the spatial heterogeneity of ecosystems, the vegetation responses to climate vary considerably with the diverse spatial patterns and the time-lag effects, which are the most important mechanism of climate-vegetation interactive effects. Extensive studies focused on large-scale vegetation-climate interactions use the simultaneous meteorological and vegetation indicators to develop models; however, the time-lag effects are less considered, which tends to increase uncertainty. In this study, we aim to quantitatively determine the time-lag effects of global vegetation responses to different climatic factors using the GIMMS3g NDVI time series and the CRU temperature, precipitation, and solar radiation datasets. First, this study analyzed the time-lag effects of global vegetation responses to different climatic factors. Then, a multiple linear regression model and partial correlation model were established to statistically analyze the roles of different climatic factors on vegetation responses, from which the primary climate-driving factors for different vegetation types were determined. The results showed that (i) both the time-lag effects of the vegetation responses and the major climate-driving factors that significantly affect vegetation growth varied significantly at the global scale, which was related to the diverse vegetation and climate characteristics; (ii) regarding the time-lag effects, the climatic factors explained 64% variation of the global vegetation growth, which was 11% relatively higher than the model ignoring the time-lag effects; (iii) for the area with a significant change trend (for the period 1982-2008) in the global GIMMS3g NDVI (P < 0.05), the primary driving factor was temperature; and (iv) at the regional scale, the variation in vegetation growth was also related to human activities and natural disturbances. Considering the time-lag effects is quite important for better predicting and evaluating the vegetation dynamics under the background of global climate change. © 2015 John Wiley & Sons Ltd.