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Sample records for modeling human respiration

  1. Simulation of Human Respiration with Breathing Thermal Manikin

    DEFF Research Database (Denmark)

    Bjørn, Erik

    The human respiration contains carbon dioxide, bioeffluents, and perhaps virus or bacteria. People may also indulge in activities that produce contaminants, as for example tobacco smoking. For these reasons, the human respiration remains one of the main contributors to contamination of the indoor...

  2. Influence of vestibular activation on respiration in humans

    Science.gov (United States)

    Monahan, Kevin D.; Sharpe, Melissa K.; Drury, Daniel; Ertl, Andrew C.; Ray, Chester A.

    2002-01-01

    The purpose of this study was to determine the effects of the semicircular canals and otolith organs on respiration in humans. On the basis of animal studies, we hypothesized that vestibular activation would elicit a vestibulorespiratory reflex. To test this hypothesis, respiratory measures, arterial blood pressure, and heart rate were measured during engagement of semicircular canals and/or otolith organs. Dynamic upright pitch and roll (15 cycles/min), which activate the otolith organs and semicircular canals, increased respiratory rate (Delta2 +/- 1 and Delta3 +/- 1 breaths/min, respectively; P respiration similarly (Delta3 +/- 1 and Delta2 +/- 1, respectively; P muscle afferent, increased respiration (Delta3 +/- 1; P muscle afferents, mediate increased ventilation in humans and support the concept that vestibular activation alters respiration in humans.

  3. Respiratory hazard assessment of combined exposure to complete gasoline exhaust and respirable volcanic ash in a multicellular human lung model at the air-liquid interface.

    Science.gov (United States)

    Tomašek, Ines; Horwell, Claire J; Bisig, Christoph; Damby, David E; Comte, Pierre; Czerwinski, Jan; Petri-Fink, Alke; Clift, Martin J D; Drasler, Barbara; Rothen-Rutishauser, Barbara

    2018-02-15

    Communities resident in urban areas located near active volcanoes can experience volcanic ash exposures during, and following, an eruption, in addition to sustained exposures to high concentrations of anthropogenic air pollutants (e.g., vehicle exhaust emissions). Inhalation of anthropogenic pollution is known to cause the onset of, or exacerbate, respiratory and cardiovascular diseases. It is further postulated similar exposure to volcanic ash can also affect such disease states. Understanding of the impact of combined exposure of volcanic ash and anthropogenic pollution to human health, however, remains limited. The aim of this study was to assess the biological impact of combined exposure to respirable volcanic ash (from Soufrière Hills volcano (SHV), Montserrat and Chaitén volcano (ChV), Chile; representing different magmatic compositions and eruption styles) and freshly-generated complete exhaust from a gasoline vehicle. A multicellular human lung model (an epithelial cell-layer composed of A549 alveolar type II-like cells complemented with human blood monocyte-derived macrophages and dendritic cells cultured at the air-liquid interface) was exposed to diluted exhaust (1:10) continuously for 6 h, followed by immediate exposure to the ash as a dry powder (0.54 ± 0.19 μg/cm 2 and 0.39 ± 0.09 μg/cm 2 for SHV and ChV ash, respectively). After an 18 h incubation, cells were exposed again for 6 h to diluted exhaust, and a final 18 h incubation (at 37 °C and 5% CO 2 ). Cell cultures were then assessed for cytotoxic, oxidative stress and (pro-)inflammatory responses. Results indicate that, at all tested (sub-lethal) concentrations, co-exposures with both ash samples induced no significant expression of genes associated with oxidative stress (HMOX1, NQO1) or production of (pro-)inflammatory markers (IL-1β, IL-8, TNF-α) at the gene and protein levels. In summary, considering the employed experimental conditions, combined exposure of

  4. Linear programming model can explain respiration of fermentation products.

    Directory of Open Access Journals (Sweden)

    Philip Möller

    Full Text Available Many differentiated cells rely primarily on mitochondrial oxidative phosphorylation for generating energy in the form of ATP needed for cellular metabolism. In contrast most tumor cells instead rely on aerobic glycolysis leading to lactate to about the same extent as on respiration. Warburg found that cancer cells to support oxidative phosphorylation, tend to ferment glucose or other energy source into lactate even in the presence of sufficient oxygen, which is an inefficient way to generate ATP. This effect also occurs in striated muscle cells, activated lymphocytes and microglia, endothelial cells and several mammalian cell types, a phenomenon termed the "Warburg effect". The effect is paradoxical at first glance because the ATP production rate of aerobic glycolysis is much slower than that of respiration and the energy demands are better to be met by pure oxidative phosphorylation. We tackle this question by building a minimal model including three combined reactions. The new aspect in extension to earlier models is that we take into account the possible uptake and oxidation of the fermentation products. We examine the case where the cell can allocate protein on several enzymes in a varying distribution and model this by a linear programming problem in which the objective is to maximize the ATP production rate under different combinations of constraints on enzymes. Depending on the cost of reactions and limitation of the substrates, this leads to pure respiration, pure fermentation, and a mixture of respiration and fermentation. The model predicts that fermentation products are only oxidized when glucose is scarce or its uptake is severely limited.

  5. A quasi-2-dimensional model for respiration of the cornea with soft contact lens wear.

    Science.gov (United States)

    Takatori, Sho C; Radke, Clayton J

    2012-04-01

    Because neither the human cornea nor a soft contact lens (SCL) is of constant thickness, corneal oxygenation varies locally. To quantify the importance of cornea/SCL thickness variations on oxygen demand, we develop a quasi-2-dimensional (2D) respiration model that accounts for aerobic and anaerobic metabolism and bicarbonate buffering. Because metabolism is critical to oxygen demand, we extend the 1-dimensional (1D), 6-layer oxygen metabolic model of Chhabra et al. Lateral diffusion is shown to be negligible. Accordingly, we adopt the 1D reactive-diffusion metabolic model but apply it locally along the cornea/lens extent. This "quasi-2D" approximation permits 2D assessment of oxygen consumption, including the effects of carbon dioxide, glucose, and lactate, bicarbonate, and hydrogen ions. We use both an oxygen deficiency factor and an excess lactate factor to gauge corneal health after accounting for both cornea and contact lens thickness variations. The quasi-2D respiration model provides quantitative spatial resolution of corneal oxygenation with minimal expenditure of computation time. When only aerobic oxygen loss is included, our quasi-2D approach is in excellent agreement with the fully 2D results of Alvord et al. However, the quasi-2D model predicts 2D concentration profiles of glucose, lactate ions, bicarbonate ions, hydrogen ions, and carbon dioxide, as well as oxygen. Neglect of metabolic reactions and/or thickness variations leads to inaccurate prediction of oxygen demand, especially near the lens periphery. The quasi-2D respiration model indicates that lateral thickness variations and respiration kinetics are critical for assessing on-eye physiologic performance of an SCL. We find that oxygen deficiency factor and excess lactate factor are useful indices to gauge corneal hypoxia. A user-friendly computer program of the quasi-2D respiration model is available for lens design.

  6. Correlation of Respirator Fit Measured on Human Subjects and a Static Advanced Headform

    Science.gov (United States)

    2016-04-19

    an elastomeric half- mask respirator fitted with an N95-rated filter cartridge and incorporates a pressure sensor to digitally log changes of in...particulate respirator and a surgical mask during human breathing: Two pathways for particle penetration. J Occup Environ Hyg. 2009; 6(10):593–603. [PubMed...Food, Drug and Cosmetic Act. J Occup Environ Hyg. Author manuscript; available in PMC 2015 June 17. A uthor M anuscript A uthor M anuscript A uthor M

  7. Oxidative stress negatively affects human sperm mitochondrial respiration.

    Science.gov (United States)

    Ferramosca, Alessandra; Pinto Provenzano, Sara; Montagna, Daniela Domenica; Coppola, Lamberto; Zara, Vincenzo

    2013-07-01

    To correlate the level of oxidative stress in serum and seminal fluid and the level of sperm deoxyribonucleic acid (DNA) fragmentation with sperm mitochondrial respiratory efficiency. Sperm mitochondrial respiratory activity was evaluated with a polarographic assay of oxygen consumption carried out in hypotonically treated sperm cells. A possible relationship between sperm mitochondrial respiratory efficiency, the level of oxidative stress, and the level of sperm DNA fragmentation was investigated. Sperm motility was positively correlated with mitochondrial respiration but negatively correlated with oxidative stress and DNA fragmentation. Interestingly, sperm mitochondrial respiratory activity was negatively affected by oxidative stress and DNA fragmentation. Our data indicate that sperm mitochondrial respiration is decreased in patients with high levels of reactive oxygen species by an uncoupling between electron transport and adenosine triphosphate synthesis. This reduction in mitochondrial functionality might be 1 of the reasons responsible for the decrease in spermatozoa motility. Copyright © 2013 Elsevier Inc. All rights reserved.

  8. Improved Detection of Human Respiration Using Data Fusion Basedon a Multistatic UWB Radar

    Directory of Open Access Journals (Sweden)

    Hao Lv

    2016-09-01

    Full Text Available This paper investigated the feasibility for improved detection of human respiration using data fusion based on a multistatic ultra-wideband (UWB radar. UWB-radar-based respiration detection is an emerging technology that has great promise in practice. It can be applied to remotely sense the presence of a human target for through-wall surveillance, post-earthquake search and rescue, etc. In these applications, a human target’s position and posture are not known a priori. Uncertainty of the two factors results in a body orientation issue of UWB radar, namely the human target’s thorax is not always facing the radar. Thus, the radial component of the thorax motion due to respiration decreases and the respiratory motion response contained in UWB radar echoes is too weak to be detected. To cope with the issue, this paper used multisensory information provided by the multistatic UWB radar, which took the form of impulse radios and comprised one transmitting and four separated receiving antennas. An adaptive Kalman filtering algorithm was then designed to fuse the UWB echo data from all the receiving channels to detect the respiratory-motion response contained in those data. In the experiment, a volunteer’s respiration was correctly detected when he curled upon a camp bed behind a brick wall. Under the same scenario, the volunteer’s respiration was detected based on the radar’s single transmitting-receiving channels without data fusion using conventional algorithm, such as adaptive line enhancer and single-channel Kalman filtering. Moreover, performance of the data fusion algorithm was experimentally investigated with different channel combinations and antenna deployments. The experimental results show that the body orientation issue for human respiration detection via UWB radar can be dealt well with the multistatic UWB radar and the Kalman-filter-based data fusion, which can be applied to improve performance of UWB radar in real applications.

  9. Measurement and Modeling of Respiration Rate of Tomato (Cultivar Roma) for Modified Atmosphere Storage.

    Science.gov (United States)

    Kandasamy, Palani; Moitra, Ranabir; Mukherjee, Souti

    2015-01-01

    Experiments were conducted to determine the respiration rate of tomato at 10, 20 and 30 °C using closed respiration system. Oxygen depletion and carbon dioxide accumulation in the system containing tomato was monitored. Respiration rate was found to decrease with increasing CO2 and decreasing O2 concentration. Michaelis-Menten type model based on enzyme kinetics was evaluated using experimental data generated for predicting the respiration rate. The model parameters that obtained from the respiration rate at different O2 and CO2 concentration levels were used to fit the model against the storage temperatures. The fitting was fair (R2 = 0.923 to 0.970) when the respiration rate was expressed as O2 concentation. Since inhibition constant for CO2 concentration tended towards negetive, the model was modified as a function of O2 concentration only. The modified model was fitted to the experimental data and showed good agreement (R2 = 0.998) with experimentally estimated respiration rate.

  10. Modulation-demodulation hypothesis of periodic breathing in human respiration.

    Science.gov (United States)

    Pal, Tanmay; Dutta, Pranab Kumar; Maka, Srinivasu

    2018-03-08

    Periodic breathing (PB) is a diseased condition of the cardiorespiratory system, and mathematically it is modelled as an oscillation. Modeling approaches replicate periodic oscillation in the minute ventilation due to a higher than normal gain of the feedback signals from the chemoreceptors coupled with a longer than normal latency in feedback, and do not consider the waxing-waning pattern of the oronasal airflow. In this work, a noted regulation model is extended by integrating respiratory mechanics and respiratory central pattern generator (rCPG) model, using modulation-demodulation 1 hypothesis. This is a top-down modeling approach, and it is assumed that the sensory feedback signal from the chemoreceptors modulates the output of the rCPG model. It is also assumed that the brainstem network is responsible for the demodulation process. The respiratory mechanics is modeled as a multi-input multi-output (MIMO) system, where modulated and demodulated neural signals are applied as input and the minute ventilation and the oronasal airflow are specified as output. The minute ventilation signal drives the regulation model, completing the feedback loop. The proposed model is validated by comparing the model output with the clinical data. Using the modulation-demodulation hypothesis, a respiratory mechanics model is formulated in the form of a linear state-space model, which can be useful for providing assisted ventilation in clinical conditions. Copyright © 2018 Elsevier B.V. All rights reserved.

  11. Lactate kinetics and mitochondrial respiration in skeletal muscle of healthy humans under influence of adrenaline.

    Science.gov (United States)

    Grip, Jonathan; Jakobsson, Towe; Hebert, Christina; Klaude, Maria; Sandström, Gustaf; Wernerman, Jan; Rooyackers, Olav

    2015-08-01

    Plasma lactate is widely used as a biomarker in critical illness. The aims of the present study were to elucidate the usefulness of a three-compartment model for muscle lactate kinetics in humans and to characterize the response to an exogenous adrenaline challenge. Repeated blood samples from artery and femoral vein together with blood flow measurements and muscle biopsies were obtained from healthy male volunteers (n=8) at baseline and during an adrenaline infusion. Concentrations of lactate and enrichment of [13C]lactate were measured and kinetics calculated. Mitochondrial activity, glycogen concentration, oxygen uptake and CO2 release were assessed. The adrenaline challenge increased plasma lactate 4-fold as a result of a greater increase in the rate of appearance (R(a)) than the increase in the rate of disappearance (R(d)). Leg muscle net release of lactate increased 3.5-fold, whereas intramuscular production had a high variation but did not change. Mitochondrial state 3 respiration increased by 30%. Glycogen concentration, oxygen uptake and CO2 production remained unchanged. In conclusion a three-compartment model gives additional information to the two-compartment model but, due to its larger variation and invasive muscle biopsy, it is less likely to become a regularly used tool in clinical research. Hyperlactataemia in response to adrenergic stimuli was driven by an elevated lactate release from skeletal muscle most probably due to a redirection of a high intramuscular turnover rather than an increased production.

  12. Temperature dependence of bulk respiration of crop stands. Measurement and model fitting

    International Nuclear Information System (INIS)

    Tani, Takashi; Arai, Ryuji; Tako, Yasuhiro

    2007-01-01

    The objective of the present study was to examine whether the temperature dependence of respiration at a crop-stand scale could be directly represented by an Arrhenius function that was widely used for representing the temperature dependence of leaf respiration. We determined temperature dependences of bulk respiration of monospecific stands of rice and soybean within a range of the air temperature from 15 to 30degC using large closed chambers. Measured responses of respiration rates of the two stands were well fitted by the Arrhenius function (R 2 =0.99). In the existing model to assess the local radiological impact of the anthropogenic carbon-14, effects of the physical environmental factors on photosynthesis and respiration of crop stands are not taken into account for the calculation of the net amount of carbon per cultivation area in crops at harvest which is the crucial parameter for the estimation of the activity concentration of carbon-14 in crops. Our result indicates that the Arrhenius function is useful for incorporating the effect of the temperature on respiration of crop stands into the model which is expected to contribute to a more realistic estimate of the activity concentration of carbon-14 in crops. (author)

  13. Fractal-Based Analysis of the Influence of Music on Human Respiration

    Science.gov (United States)

    Reza Namazi, H.

    An important challenge in respiration related studies is to investigate the influence of external stimuli on human respiration. Auditory stimulus is an important type of stimuli that influences human respiration. However, no one discovered any trend, which relates the characteristics of the auditory stimuli to the characteristics of the respiratory signal. In this paper, we investigate the correlation between auditory stimuli and respiratory signal from fractal point of view. We found out that the fractal structure of respiratory signal is correlated with the fractal structure of the applied music. Based on the obtained results, the music with greater fractal dimension will result in respiratory signal with smaller fractal dimension. In order to verify this result, we benefit from approximate entropy. The results show the respiratory signal will have smaller approximate entropy by choosing the music with smaller approximate entropy. The method of analysis could be further investigated to analyze the variations of different physiological time series due to the various types of stimuli when the complexity is the main concern.

  14. Reverse engineering model structures for soil and ecosystem respiration: the potential of gene expression programming

    Science.gov (United States)

    Ilie, Iulia; Dittrich, Peter; Carvalhais, Nuno; Jung, Martin; Heinemeyer, Andreas; Migliavacca, Mirco; Morison, James I. L.; Sippel, Sebastian; Subke, Jens-Arne; Wilkinson, Matthew; Mahecha, Miguel D.

    2017-09-01

    Accurate model representation of land-atmosphere carbon fluxes is essential for climate projections. However, the exact responses of carbon cycle processes to climatic drivers often remain uncertain. Presently, knowledge derived from experiments, complemented by a steadily evolving body of mechanistic theory, provides the main basis for developing such models. The strongly increasing availability of measurements may facilitate new ways of identifying suitable model structures using machine learning. Here, we explore the potential of gene expression programming (GEP) to derive relevant model formulations based solely on the signals present in data by automatically applying various mathematical transformations to potential predictors and repeatedly evolving the resulting model structures. In contrast to most other machine learning regression techniques, the GEP approach generates readable models that allow for prediction and possibly for interpretation. Our study is based on two cases: artificially generated data and real observations. Simulations based on artificial data show that GEP is successful in identifying prescribed functions, with the prediction capacity of the models comparable to four state-of-the-art machine learning methods (random forests, support vector machines, artificial neural networks, and kernel ridge regressions). Based on real observations we explore the responses of the different components of terrestrial respiration at an oak forest in south-eastern England. We find that the GEP-retrieved models are often better in prediction than some established respiration models. Based on their structures, we find previously unconsidered exponential dependencies of respiration on seasonal ecosystem carbon assimilation and water dynamics. We noticed that the GEP models are only partly portable across respiration components, the identification of a general terrestrial respiration model possibly prevented by equifinality issues. Overall, GEP is a promising

  15. Reverse engineering model structures for soil and ecosystem respiration: the potential of gene expression programming

    Directory of Open Access Journals (Sweden)

    I. Ilie

    2017-09-01

    Full Text Available Accurate model representation of land–atmosphere carbon fluxes is essential for climate projections. However, the exact responses of carbon cycle processes to climatic drivers often remain uncertain. Presently, knowledge derived from experiments, complemented by a steadily evolving body of mechanistic theory, provides the main basis for developing such models. The strongly increasing availability of measurements may facilitate new ways of identifying suitable model structures using machine learning. Here, we explore the potential of gene expression programming (GEP to derive relevant model formulations based solely on the signals present in data by automatically applying various mathematical transformations to potential predictors and repeatedly evolving the resulting model structures. In contrast to most other machine learning regression techniques, the GEP approach generates readable models that allow for prediction and possibly for interpretation. Our study is based on two cases: artificially generated data and real observations. Simulations based on artificial data show that GEP is successful in identifying prescribed functions, with the prediction capacity of the models comparable to four state-of-the-art machine learning methods (random forests, support vector machines, artificial neural networks, and kernel ridge regressions. Based on real observations we explore the responses of the different components of terrestrial respiration at an oak forest in south-eastern England. We find that the GEP-retrieved models are often better in prediction than some established respiration models. Based on their structures, we find previously unconsidered exponential dependencies of respiration on seasonal ecosystem carbon assimilation and water dynamics. We noticed that the GEP models are only partly portable across respiration components, the identification of a general terrestrial respiration model possibly prevented by equifinality issues. Overall

  16. A novel high-throughput assay for islet respiration reveals uncoupling of rodent and human islets.

    Directory of Open Access Journals (Sweden)

    Jakob D Wikstrom

    Full Text Available The pancreatic beta cell is unique in its response to nutrient by increased fuel oxidation. Recent studies have demonstrated that oxygen consumption rate (OCR may be a valuable predictor of islet quality and long term nutrient responsiveness. To date, high-throughput and user-friendly assays for islet respiration are lacking. The aim of this study was to develop such an assay and to examine bioenergetic efficiency of rodent and human islets.The XF24 respirometer platform was adapted to islets by the development of a 24-well plate specifically designed to confine islets. The islet plate generated data with low inter-well variability and enabled stable measurement of oxygen consumption for hours. The F1F0 ATP synthase blocker oligomycin was used to assess uncoupling while rotenone together with myxothiazol/antimycin was used to measure the level of non-mitochondrial respiration. The use of oligomycin in islets was validated by reversing its effect in the presence of the uncoupler FCCP. Respiratory leak averaged to 59% and 49% of basal OCR in islets from C57Bl6/J and FVB/N mice, respectively. In comparison, respiratory leak of INS-1 cells and C2C12 myotubes was measured to 38% and 23% respectively. Islets from a cohort of human donors showed a respiratory leak of 38%, significantly lower than mouse islets.The assay for islet respiration presented here provides a novel tool that can be used to study islet mitochondrial function in a relatively high-throughput manner. The data obtained in this study shows that rodent islets are less bioenergetically efficient than human islets as well as INS1 cells.

  17. Effect of ECG-derived respiration (EDR) on modeling ventricular repolarization dynamics in different physiological and psychological conditions.

    Science.gov (United States)

    Imam, M H; Karmakar, C K; Khandoker, A H; Palaniswami, M

    2014-10-01

    Ventricular repolarization dynamics is an important predictor of the outcome in cardiovascular diseases. Mathematical modeling of the heart rate variability (RR interval variability) and ventricular repolarization variability (QT interval variability) is one of the popular methods to understand the dynamics of ventricular repolarization. Although ECG derived respiration (EDR) was previously suggested as a surrogate of respiration, but the effect of respiratory movement on ventricular repolarization dynamics was not studied. In this study, the importance of considering the effect of respiration and the validity of using EDR as a surrogate of respiration for linear parametric modeling of ventricular repolarization variability is studied in two cases with different physiological and psychological conditions. In the first case study, we used 20 young and 20 old healthy subjects' ECG and respiration data from Fantasia database at Physionet to analyze a bivariate QT-RR and a trivariate [Formula: see text] model structure to study the aging effect on cardiac repolarization variability. In the second study, we used 16 healthy subjects' data from drivedb (stress detection for automobile drivers) database at Physionet to do the same analysis for different psychological condition (i.e., in stressed and no stress condition). The results of our study showed that model having respiratory information (QT-RR-RESP and QT-RR-EDR) gave significantly better fit value (p 0.05) performance as that of respiration as an exogenous model input in describing repolarization variability irrespective of age and different mental conditions. Another finding of our study is that both respiration and EDR-based models can significantly (p < 0.05) differentiate the ventricular repolarization dynamics between healthy subjects of different age groups and with different psychological conditions, whereas models without respiration or EDR cannot distinguish between the groups. These results established

  18. Quantification of Model Uncertainty in Modeling Mechanisms of Soil Microbial Respiration Pulses to Simulate Birch Effect

    Science.gov (United States)

    Elshall, A. S.; Ye, M.; Niu, G. Y.; Barron-Gafford, G.

    2014-12-01

    A Bayesian framework is developed to quantify predictive uncertainty in environmental modeling caused by uncertainty in modeling scenarios, model structures, model parameters, and data. An example of using the framework to quantify model uncertainty is presented to simulate soil microbial respiration pulses in response to episodic rainfall pulses (the "Birch effect"). A total of five models are developed; they evolve from an existing four-carbon (C) pool model to models with additional C pools and recently developed models with explicit representations of soil moisture controls on C degradation and microbial uptake rates. Markov chain Monte Carlo (MCMC) methods with generalized likelihood function (not Gaussian) are used to estimate posterior parameter distributions of the models, and the posterior parameter samples are used to evaluate probabilities of the models. The models with explicit representations of soil moisture controls outperform the other models. The models with additional C pools for accumulation of degraded C in the dry zone of the soil pore space result in a higher probability of reproducing the observed Birch pulses. A cross-validation is conducted to explore predictive performance of model averaging and of individual models. The Bayesian framework is mathematically general and can be applied to a wide range of environmental problems.

  19. Omega-3 supplementation alters mitochondrial membrane composition and respiration kinetics in human skeletal muscle.

    Science.gov (United States)

    Herbst, E A F; Paglialunga, S; Gerling, C; Whitfield, J; Mukai, K; Chabowski, A; Heigenhauser, G J F; Spriet, L L; Holloway, G P

    2014-03-15

    Studies have shown increased incorporation of omega-3 fatty acids into whole skeletal muscle following supplementation, although little has been done to investigate the potential impact on the fatty acid composition of mitochondrial membranes and the functional consequences on mitochondrial bioenergetics. Therefore, we supplemented young healthy male subjects (n = 18) with fish oils [2 g eicosapentaenoic acid (EPA) and 1 g docosahexanoic acid (DHA) per day] for 12 weeks and skeletal muscle biopsies were taken prior to (Pre) and following (Post) supplementation for the analysis of mitochondrial membrane phospholipid composition and various assessments of mitochondrial bioenergetics. Total EPA and DHA content in mitochondrial membranes increased (P respiration, determined in permeabilized muscle fibres, demonstrated no change in maximal substrate-supported respiration, or in the sensitivity (apparent Km) and maximal capacity for pyruvate-supported respiration. In contrast, mitochondrial responses during ADP titrations demonstrated an enhanced ADP sensitivity (decreased apparent Km) that was independent of the creatine kinase shuttle. As the content of ANT1, ANT2, and subunits of the electron transport chain were unaltered by supplementation, these data suggest that prolonged omega-3 intake improves ADP kinetics in human skeletal muscle mitochondria through alterations in membrane structure and/or post-translational modification of ATP synthase and ANT isoforms. Omega-3 supplementation also increased the capacity for mitochondrial reactive oxygen species emission without altering the content of oxidative products, suggesting the absence of oxidative damage. The current data strongly emphasize a role for omega-3s in reorganizing the composition of mitochondrial membranes while promoting improvements in ADP sensitivity.

  20. Dynamic modeling of lung tumor motion during respiration

    Energy Technology Data Exchange (ETDEWEB)

    Kyriakou, E; McKenzie, D R, E-mail: e.kyriakou@physics.usyd.edu.au, E-mail: d.mckenzie@physics.usyd.edu.au [School of Physics, University of Sydney, NSW 2006 (Australia)

    2011-05-21

    A dynamic finite element model of the lung that incorporates a simplified geometry with realistic lung material properties has been developed. Observations of lung motion from respiratory-gated computed tomography were used to provide a database against which the predictions of the model are assessed. Data from six patients presenting with lung tumors were processed to give sagittal sections of the lung containing the tumor as a function of the breathing phase. Statistical shape modeling was used to outline the diaphragm, the tumor volume and the thoracic wall at each breathing phase. The motion of the tumor in the superior-inferior direction was plotted against the diaphragm displacement. The finite element model employed a simplified geometry in which the lung material fills a rectangular volume enabling two-dimensional coordinates to be used. The diaphragm is represented as a piston, driving the motion. Plots of lung displacement against diaphragm displacement form hysteresis loops that are a sensitive indicator of the characteristics of the motion. The key parameters of lung material that determine the motion are the density and elastic properties of lung material and the airway permeability. The model predictions of the hysteresis behavior agreed well with observation only when lung material is modeled as viscoelastic. The key material parameters are suggested for use as prognostic indicators of the progression of disease and of changes arising from the response of the lung to radiation treatment.

  1. Mitochondrial respiration in human viable platelets-Methodology and influence of gender, age and storage

    DEFF Research Database (Denmark)

    Sjövall, Fredrik; Ehinger, Johannes K H; Marelsson, Sigurður E

    2013-01-01

    Studying whole cell preparations with intact mitochondria and respiratory complexes has a clear benefit compared to isolated or disrupted mitochondria due to the dynamic interplay between mitochondria and other cellular compartments. Platelet mitochondria have a potential to serve as a source...... of human viable mitochondria when studying mitochondrial physiology and pathogenic mechanisms, as well as for the diagnostics of mitochondrial diseases. The objective of the present study was to perform a detailed evaluation of platelet mitochondrial respiration using high-resolution respirometry. Further......, we aimed to explore the limits of sample size and the impact of storage as well as to establish a wide range of reference data from different pediatric and adult cohorts. Our results indicate that platelet mitochondria are well suited for ex-vivo analysis with the need for minute sample amounts...

  2. Simvastatin impairs ADP-stimulated respiration and increases mitochondrial oxidative stress in primary human skeletal myotubes.

    Science.gov (United States)

    Kwak, Hyo-Bum; Thalacker-Mercer, Anna; Anderson, Ethan J; Lin, Chien-Te; Kane, Daniel A; Lee, Nam-Sihk; Cortright, Ronald N; Bamman, Marcas M; Neufer, P Darrell

    2012-01-01

    Statins, the widely prescribed cholesterol-lowering drugs for the treatment of cardiovascular disease, cause adverse skeletal muscle side effects ranging from fatigue to fatal rhabdomyolysis. The purpose of this study was to determine the effects of simvastatin on mitochondrial respiration, oxidative stress, and cell death in differentiated primary human skeletal muscle cells (i.e., myotubes). Simvastatin induced a dose-dependent decrease in viability of proliferating and differentiating primary human muscle precursor cells, and a similar dose-dependent effect was noted in differentiated myoblasts and myotubes. Additionally, there were decreases in myotube number and size following 48 h of simvastatin treatment (5 μM). In permeabilized myotubes, maximal ADP-stimulated oxygen consumption, supported by palmitoylcarnitine+malate (PCM, complex I and II substrates) and glutamate+malate (GM, complex I substrates), was 32-37% lower (Prespiration at complex I. Mitochondrial superoxide and hydrogen peroxide generation were significantly greater in the simvastatin-treated human skeletal myotube cultures compared to control. In addition, simvastatin markedly increased protein levels of Bax (proapoptotic, +53%) and Bcl-2 (antiapoptotic, +100%, P<0.05), mitochondrial PTP opening (+44%, P<0.05), and TUNEL-positive nuclei in human skeletal myotubes, demonstrating up-regulation of mitochondrial-mediated myonuclear apoptotic mechanisms. These data demonstrate that simvastatin induces myotube atrophy and cell loss associated with impaired ADP-stimulated maximal mitochondrial respiratory capacity, mitochondrial oxidative stress, and apoptosis in primary human skeletal myotubes, suggesting that mitochondrial dysfunction may underlie human statin-induced myopathy. Copyright © 2011 Elsevier Inc. All rights reserved.

  3. Modeling of heart sound morphology and analysis of the morphological variations induced by respiration.

    Science.gov (United States)

    Tang, Hong; Gao, Jiao; Ruan, Chengjie; Qiu, Tianshuang; Park, Yongwan

    2013-11-01

    In this study, each peak/valley of a heart sound was modeled by a Gaussian curve and characterized by amplitude, timing, and supporting width. This model was applied to analyze the morphological variations induced by respiration in 12 subjects. It was observed that the morphology exhibited regular behaviors with respiration. The amplitude of the prominent peaks and valleys of S2 (the second heart sound) were commonly attenuated during expiration and were accentuated during inspiration whereas no consistent observations were obtained for S1 (the first heart sound). The supporting width of S1 commonly decreased with expiration and increased with inspiration whereas the supporting width of S2 displayed no significant changes during respiration. For all subjects, the delay of S1 increased during inspiration and decreased during expiration. However, the delay of the aortic component increased during expiration and decreased during inspiration. The pulmonary component of S2 was observed in 7 of 12 subjects, and the delay was opposite to that of the aortic component. The opposing delays yielded a splitting between the two components of S2 that increased during inspiration and decreased during expiration. The delay pattern was the most consistent observation in all subjects. These results suggest that a quantitative analysis of morphological variations, particularly the delay pattern, could be used as a non-invasive continuous monitoring method of hemodynamic change during respiratory cycles. © 2013 Elsevier Ltd. All rights reserved.

  4. Slow and deep respiration suppresses steady-state sympathetic nerve activity in patients with chronic heart failure: from modeling to clinical application.

    Science.gov (United States)

    Harada, Daisuke; Asanoi, Hidetsugu; Takagawa, Junya; Ishise, Hisanari; Ueno, Hiroshi; Oda, Yoshitaka; Goso, Yukiko; Joho, Shuji; Inoue, Hiroshi

    2014-10-15

    Influences of slow and deep respiration on steady-state sympathetic nerve activity remain controversial in humans and could vary depending on disease conditions and basal sympathetic nerve activity. To elucidate the respiratory modulation of steady-state sympathetic nerve activity, we modeled the dynamic nature of the relationship between lung inflation and muscle sympathetic nerve activity (MSNA) in 11 heart failure patients with exaggerated sympathetic outflow at rest. An autoregressive exogenous input model was utilized to simulate entire responses of MSNA to variable respiratory patterns. In another 18 patients, we determined the influence of increasing tidal volume and slowing respiratory frequency on MSNA; 10 patients underwent a 15-min device-guided slow respiration and the remaining 8 had no respiratory modification. The model predicted that a 1-liter, step increase of lung volume decreased MSNA dynamically; its nadir (-33 ± 22%) occurred at 2.4 s; and steady-state decrease (-15 ± 5%), at 6 s. Actually, in patients with the device-guided slow and deep respiration, respiratory frequency effectively fell from 16.4 ± 3.9 to 6.7 ± 2.8/min (P steady-state MSNA was decreased by 31% (P steady-state MSNA. Thus slow and deep respiration suppresses steady-state sympathetic nerve activity in patients with high levels of resting sympathetic tone as in heart failure. Copyright © 2014 the American Physiological Society.

  5. Imeglimin prevents human endothelial cell death by inhibiting mitochondrial permeability transition without inhibiting mitochondrial respiration.

    Science.gov (United States)

    Detaille, D; Vial, G; Borel, A-L; Cottet-Rouselle, C; Hallakou-Bozec, S; Bolze, S; Fouqueray, P; Fontaine, E

    2016-01-01

    Imeglimin is the first in a new class of oral glucose-lowering agents, having recently completed its phase 2b trial. As Imeglimin did show a full prevention of β-cell apoptosis, and since angiopathy represents a major complication of diabetes, we studied Imeglimin protective effects on hyperglycemia-induced death of human endothelial cells (HMEC-1). These cells were incubated in several oxidative stress environments (exposure to high glucose and oxidizing agent tert-butylhydroperoxide) which led to mitochondrial permeability transition pore (PTP) opening, cytochrome c release and cell death. These events were fully prevented by Imeglimin treatment. This protective effect on cell death occurred without any effect on oxygen consumption rate, on lactate production and on cytosolic redox or phosphate potentials. Imeglimin also dramatically decreased reactive oxygen species production, inhibiting specifically reverse electron transfer through complex I. We conclude that Imeglimin prevents hyperglycemia-induced cell death in HMEC-1 through inhibition of PTP opening without inhibiting mitochondrial respiration nor affecting cellular energy status. Considering the high prevalence of macrovascular and microvascular complications in type 2 diabetic subjects, these results together suggest a potential benefit of Imeglimin in diabetic angiopathy.

  6. The value of soil respiration measurements for interpreting and modeling terrestrial carbon cycling

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, Claire L.; Bond-Lamberty, Ben; Desai, Ankur R.; Lavoie, Martin; Risk, Dave; Tang, Jianwu; Todd-Brown, Katherine; Vargas, Rodrigo

    2016-11-16

    A recent acceleration of model-data synthesis activities has leveraged many terrestrial carbon (C) datasets, but utilization of soil respiration (RS) data has not kept pace with other types such as eddy covariance (EC) fluxes and soil C stocks. Here we argue that RS data, including non-continuous measurements from survey sampling campaigns, have unrealized value and should be utilized more extensively and creatively in data synthesis and modeling activities. We identify three major challenges in interpreting RS data, and discuss opportunities to address them. The first challenge is that when RS is compared to ecosystem respiration (RECO) measured from EC towers, it is not uncommon to find substantial mismatch, indicating one or both flux methodologies are unreliable. We argue the most likely cause of mismatch is unreliable EC data, and there is an unrecognized opportunity to utilize RS for EC quality control. The second challenge is that RS integrates belowground heterotrophic (RH) and autotrophic (RA) activity, whereas modelers generally prefer partitioned fluxes, and few models include an explicit RS output. Opportunities exist to use the total RS flux for data assimilation and model benchmarking methods rather than less-certain partitioned fluxes. Pushing for more experiments that not only partition RS but also monitor the age of RA and RH, as well as for the development of belowground RA components in models, would allow for more direct comparison between measured and modeled values. The third challenge is that soil respiration is generally measured at a very different resolution than that needed for comparison to EC or ecosystem- to global-scale models. Measuring soil fluxes with finer spatial resolution and more extensive coverage, and downscaling EC fluxes to match the scale of RS, will improve chamber and tower comparisons. Opportunities also exist to estimate RH at regional scales by implementing decomposition functional types, akin to plant functional

  7. Plasma Amino Acids Stimulate Uncoupled Respiration of Muscle Subsarcolemmal Mitochondria in Lean but Not Obese Humans.

    Science.gov (United States)

    Kras, Katon A; Hoffman, Nyssa; Roust, Lori R; Patel, Shivam H; Carroll, Chad C; Katsanos, Christos S

    2017-12-01

    Obesity is associated with mitochondrial dysfunction in skeletal muscle. Increasing the plasma amino acid (AA) concentrations stimulates mitochondrial adenosine triphosphate (ATP) production in lean individuals. To determine whether acute elevation in plasma AAs enhances muscle mitochondrial respiration and ATP production in subsarcolemmal (SS) and intermyofibrillar (IMF) mitochondria in obese adults. Assessment of SS and IMF mitochondrial function during saline (i.e., control) and AA infusions. Eligible participants were healthy lean (body mass index, 30 kg/m2; age 35 ± 3 years; n = 11) subjects. Single trial of saline infusion followed by AA infusion. SS and IMF mitochondria were isolated from muscle biopsies collected at the end of the saline and AA infusions. Mitochondrial respiration and ATP production. AA infusion increased adenosine 5'-diphosphate (ADP)-stimulated respiration and ATP production rates of SS mitochondria in the lean (P lean subjects only (P lean or obese subjects (P > 0.05). Increasing the plasma AA concentrations enhances the capacity for respiration and ATP production of muscle SS, but not IMF, mitochondria in lean individuals, in parallel with increases in uncoupled respiration. However, neither of these parameters increases in muscle SS or IMF mitochondria in obese individuals. Copyright © 2017 Endocrine Society

  8. Reducing Uncertainty in the Daycent Model of Heterotrophic Respiration with a More Mechanistic Representation of Microbial Processes.

    Science.gov (United States)

    Berardi, D.; Gomez-Casanovas, N.; Hudiburg, T. W.

    2017-12-01

    Improving the certainty of ecosystem models is essential to ensuring their legitimacy, value, and ability to inform management and policy decisions. With more than a century of research exploring the variables controlling soil respiration, a high level of uncertainty remains in the ability of ecosystem models to accurately estimate respiration with changing climatic conditions. Refining model estimates of soil carbon fluxes is a high priority for climate change scientists to determine whether soils will be carbon sources or sinks in the future. We found that DayCent underestimates heterotrophic respiration by several magnitudes for our temperate mixed conifer forest site. While traditional ecosystem models simulate decomposition through first order kinetics, recent research has found that including microbial mechanisms explains 20 percent more spatial heterogeneity. We manipulated the DayCent heterotrophic respiration model to include a more mechanistic representation of microbial dynamic and compared the new model with continuous and survey observations from our experimental forest site in the Northern Rockies ecoregion. We also calibrated the model's sensitivity to soil moisture and temperature to our experimental data. We expect to improve the accuracy of the model by 20-30 percent. By using a more representative and calibrated model of soil carbon dynamics, we can better predict feedbacks between climate and soil carbon pools.

  9. Reduction of irregular breathing artifacts in respiration-correlated CT images using a respiratory motion model.

    Science.gov (United States)

    Hertanto, Agung; Zhang, Qinghui; Hu, Yu-Chi; Dzyubak, Oleksandr; Rimner, Andreas; Mageras, Gig S

    2012-06-01

    Respiration-correlated CT (RCCT) images produced with commonly used phase-based sorting of CT slices often exhibit discontinuity artifacts between CT slices, caused by cycle-to-cycle amplitude variations in respiration. Sorting based on the displacement of the respiratory signal yields slices at more consistent respiratory motion states and hence reduces artifacts, but missing image data (gaps) may occur. The authors report on the application of a respiratory motion model to produce an RCCT image set with reduced artifacts and without missing data. Input data consist of CT slices from a cine CT scan acquired while recording respiration by monitoring abdominal displacement. The model-based generation of RCCT images consists of four processing steps: (1) displacement-based sorting of CT slices to form volume images at 10 motion states over the cycle; (2) selection of a reference image without gaps and deformable registration between the reference image and each of the remaining images; (3) generation of the motion model by applying a principal component analysis to establish a relationship between displacement field and respiration signal at each motion state; (4) application of the motion model to deform the reference image into images at the 9 other motion states. Deformable image registration uses a modified fast free-form algorithm that excludes zero-intensity voxels, caused by missing data, from the image similarity term in the minimization function. In each iteration of the minimization, the displacement field in the gap regions is linearly interpolated from nearest neighbor nonzero intensity slices. Evaluation of the model-based RCCT examines three types of image sets: cine scans of a physical phantom programmed to move according to a patient respiratory signal, NURBS-based cardiac torso (NCAT) software phantom, and patient thoracic scans. Comparison in physical motion phantom shows that object distortion caused by variable motion amplitude in phase

  10. Real-time human respiration carbon dioxide measurement device for cardiorespiratory assessment.

    Science.gov (United States)

    Singh, Om Prakash; Howe, Teo Aik; Malarvili, M B

    2018-01-04

    The development of a human respiration carbon dioxide (CO 2 ) measurement device to evaluate cardiorespiratory status inside and outside a hospital setting has proven to be a challenging area of research over the few last decades. Hence, we report a real-time, user operable CO 2 measurement device using an infrared CO 2 sensor (Arduino Mega2560) and a thin film transistor (TFT, 3.5″), incorporated with low pass (cut-off frequency, 10 Hz) and moving average (span, 8) filters. The proposed device measures features such as partial end-tidal carbon dioxide (EtCO 2 ), respiratory rate (RR), inspired carbon dioxide (ICO 2 ), and a newly proposed feature-Hjorth activity-that annotates data with the date and time from a real-time clock, and is stored onto a secure digital (SD) card. Further, it was tested on 22 healthy subjects and the performance (reliability, validity and relationship) of each feature was established using (1) an intraclass correlation coefficient (ICC), (2) standard error measurement (SEM), (3) smallest detectable difference (SDD), (4) Bland-Altman plot, and (5) Pearson's correlation (r). The SEM, SDD, and ICC values for inter- and intra-rater reliability were less than 5% and more than 0.8, respectively. Further, the Bland-Altman plot demonstrates that mean differences ± standard deviations for a set limit were 0.30 ± 0.77 mmHg, -0.34 ± 1.41 mmHg and 0.21 ± 0.64 breath per minute (bpm) for CO 2 , EtCO 2 and RR. The findings revealed that the developed device is highly reliable, providing valid measurements for CO 2 , EtCO 2 , ICO 2 and RR, and can be used in clinical settings for cardiorespiratory assessment. This research also demonstrates that EtCO 2 and RR (r, -0.696) are negatively correlated while EtCO 2 and activity (r, 0.846) are positively correlated. Thus, simultaneous measurement of these features may possibly assist physicians in understanding the subject's cardiopulmonary status. In future, the proposed device will be tested

  11. A Satellite-Based Model for Simulating Ecosystem Respiration in the Tibetan and Inner Mongolian Grasslands

    Directory of Open Access Journals (Sweden)

    Rong Ge

    2018-01-01

    Full Text Available It is important to accurately evaluate ecosystem respiration (RE in the alpine grasslands of the Tibetan Plateau and the temperate grasslands of the Inner Mongolian Plateau, as it serves as a sensitivity indicator of regional and global carbon cycles. Here, we combined flux measurements taken between 2003 and 2013 from 16 grassland sites across northern China and the corresponding MODIS land surface temperature (LST, enhanced vegetation index (EVI, and land surface water index (LSWI to build a satellite-based model to estimate RE at a regional scale. First, the dependencies of both spatial and temporal variations of RE on these biotic and climatic factors were examined explicitly. We found that plant productivity and moisture, but not temperature, can best explain the spatial pattern of RE in northern China’s grasslands; while temperature plays a major role in regulating the temporal variability of RE in the alpine grasslands, and moisture is equally as important as temperature in the temperate grasslands. However, the moisture effect on RE and the explicit representation of spatial variation process are often lacking in most of the existing satellite-based RE models. On this basis, we developed a model by comprehensively considering moisture, temperature, and productivity effects on both temporal and spatial processes of RE, and then, we evaluated the model performance. Our results showed that the model well explained the observed RE in both the alpine (R2 = 0.79, RMSE = 0.77 g C m−2 day−1 and temperate grasslands (R2 = 0.75, RMSE = 0.60 g C m−2 day−1. The inclusion of the LSWI as the water-limiting factor substantially improved the model performance in arid and semi-arid ecosystems, and the spatialized basal respiration rate as an indicator for spatial variation largely determined the regional pattern of RE. Finally, the model accurately reproduced the seasonal and inter-annual variations and spatial variability of RE, and it avoided

  12. Estimation of microbial respiration rates in groundwater by geochemical modeling constrained with stable isotopes

    Science.gov (United States)

    Murphy, E. M.; Schramke, J. A.

    1998-11-01

    Changes in geochemistry and stable isotopes along a well-established groundwater flow path were used to estimate in situ microbial respiration rates in the Middendorf aquifer in the southeastern United States. Respiration rates were determined for individual terminal electron acceptors including O 2, MnO 2, Fe 3+, and SO 42-. The extent of biotic reactions were constrained by the fractionation of stable isotopes of carbon and sulfur. Sulfur isotopes and the presence of sulfur-oxidizing microorganisms indicated that sulfate is produced through the oxidation of reduced sulfur species in the aquifer and not by the dissolution of gypsum, as previously reported. The respiration rates varied along the flow path as the groundwater transitioned between primarily oxic to anoxic conditions. Iron-reducing microorganisms were the largest contributors to the oxidation of organic matter along the portion of the groundwater flow path investigated in this study. The transition zone between oxic and anoxic groundwater contained a wide range of terminal electron acceptors and showed the greatest diversity and numbers of culturable microorganisms and the highest respiration rates. A comparison of respiration rates measured from core samples and pumped groundwater suggests that variability in respiration rates may often reflect the measurement scales, both in the sample volume and the time-frame over which the respiration measurement is averaged. Chemical heterogeneity may create a wide range of respiration rates when the scale of the observation is below the scale of the heterogeneity.

  13. Pantothenate kinase-associated neurodegeneration: altered mitochondria membrane potential and defective respiration in Pank2 knock-out mouse model.

    Science.gov (United States)

    Brunetti, Dario; Dusi, Sabrina; Morbin, Michela; Uggetti, Andrea; Moda, Fabio; D'Amato, Ilaria; Giordano, Carla; d'Amati, Giulia; Cozzi, Anna; Levi, Sonia; Hayflick, Susan; Tiranti, Valeria

    2012-12-15

    Neurodegeneration with brain iron accumulation (NBIA) comprises a group of neurodegenerative disorders characterized by high brain content of iron and presence of axonal spheroids. Mutations in the PANK2 gene, which encodes pantothenate kinase 2, underlie an autosomal recessive inborn error of coenzyme A metabolism, called pantothenate kinase-associated neurodegeneration (PKAN). PKAN is characterized by dystonia, dysarthria, rigidity and pigmentary retinal degeneration. The pathogenesis of this disorder is poorly understood and, although PANK2 is a mitochondrial protein, perturbations in mitochondrial bioenergetics have not been reported. A knock-out (KO) mouse model of PKAN exhibits retinal degeneration and azoospermia, but lacks any neurological phenotype. The absence of a clinical phenotype has partially been explained by the different cellular localization of the human and murine PANK2 proteins. Here we demonstrate that the mouse Pank2 protein localizes to mitochondria, similar to its human orthologue. Moreover, we show that Pank2-defective neurons derived from KO mice have an altered mitochondrial membrane potential, a defect further corroborated by the observations of swollen mitochondria at the ultra-structural level and by the presence of defective respiration.

  14. CARVE Modeled Gross Ecosystem CO2 Exchange and Respiration, Alaska, 2012-2014

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set provides 3-hourly estimates of gross ecosystem CO2 exchange (GEE) and respiration (autotrophic and heterotrophic) for the state of Alaska from 2012 to...

  15. Smart textile sensing system for human respiration monitoring based on fiber Bragg grating

    Science.gov (United States)

    Zhang, Cheng; Miao, Chang-yun; Li, Hong-qiang; Song, Hui-chao; Xu, Fan-jie

    2009-07-01

    Magnetic resonance imaging (MRI) has become an indispensable aid to diagnosis and treatment. As the doctor cannot accompany the patient, it is essential that the patient be monitored remotely to avoid the risk of respiration being impaired by anesthetic drugs or upper airway obstruction. A smart wearable textile sensing system is described in this paper. A fiber Bragg grating (FBG) with polymer encapsulation has been woven into an elastic bandage to detect the respiration motion. According to the strain principle of FBG, the breathing rate and intensity can be obtained by measuring the variety of FBG reflected wavelength. In order to eliminate the temperature cross-sensitivity, a FBG temperature sensor has also been woven into the bandage to achieve the temperature compensation computing. Based on the tunable Fabry-Perot filter wavelength demodulated theory, wavelength measuring method and data processing arithmetic have been presented, and the system with ARM microprocessor has been designed to process and display the breathing information. The experiments to the system have proved that the wavelength measuring range is about 40nm, the resolution of wavelength can arrive at 2pm, and the sampling rate is 5Hz.

  16. Model prediction of biome-specific global soil respiration from 1960 to 2012

    Science.gov (United States)

    Zhao, Zhengyong; Peng, Changhui; Yang, Qi; Meng, Fan-Rui; Song, Xinzhang; Chen, Shutao; Epule, Terence Epule; Li, Peng; Zhu, Qiuan

    2017-07-01

    Biome-specific soil respiration (Rs) has important yet different roles in both the carbon cycle and climate change from regional to global scales. To date, no comparable studies related to global biome-specific Rs have been conducted applying comprehensive global Rs databases. The goal of this study was to develop artificial neural network (ANN) models capable of spatially estimating global Rs and to evaluate the effects of interannual climate variations on 10 major biomes. We used 1976 annual Rs field records extracted from global Rs literature to train and test the ANN models. We determined that the best ANN model for predicting biome-specific global annual Rs was the one that applied mean annual temperature (MAT), mean annual precipitation (MAP), and biome type as inputs (r2 = 0.60). The ANN models reported an average global Rs of 93.3 ± 6.1 Pg C yr-1 from 1960 to 2012 and an increasing trend in average global annual Rs of 0.04 Pg C yr-1. Estimated annual Rs increased with increases in MAT and MAP in cropland, boreal forest, grassland, shrubland, and wetland biomes. Additionally, estimated annual Rs decreased with increases in MAT and increased with increases in MAP in desert and tundra biomes, and only significantly decreased with increases in MAT (r2 = 0.87) in the savannah biome. The developed biome-specific global Rs database for global land and soil carbon models will aid in understanding the mechanisms underlying variations in soil carbon dynamics and in quantifying uncertainty in the global soil carbon cycle.

  17. Scalability of human models

    NARCIS (Netherlands)

    Rodarius, C.; Rooij, L. van; Lange, R. de

    2007-01-01

    The objective of this work was to create a scalable human occupant model that allows adaptation of human models with respect to size, weight and several mechanical parameters. Therefore, for the first time two scalable facet human models were developed in MADYMO. First, a scalable human male was

  18. Dynamic relationships between microbial biomass, respiration, inorganic nutrients and enzyme activities: informing enzyme based decomposition models

    Directory of Open Access Journals (Sweden)

    Daryl L Moorhead

    2013-08-01

    Full Text Available We re-examined data from a recent litter decay study to determine if additional insights could be gained to inform decomposition modeling. Rinkes et al. (2013 conducted 14-day laboratory incubations of sugar maple (Acer saccharum or white oak (Quercus alba leaves, mixed with sand (0.4% organic C content or loam (4.1% organic C. They measured microbial biomass C, carbon dioxide efflux, soil ammonium, nitrate, and phosphate concentrations, and β-glucosidase (BG, β-N-acetyl-glucosaminidase (NAG, and acid phosphatase (AP activities on days 1, 3, and 14. Analyses of relationships among variables yielded different insights than original analyses of individual variables. For example, although respiration rates per g soil were higher for loam than sand, rates per g soil C were actually higher for sand than loam, and rates per g microbial C showed little difference between treatments. Microbial biomass C peaked on day 3 when biomass-specific activities of enzymes were lowest, suggesting uptake of litter C without extracellular hydrolysis. This result refuted a common model assumption that all enzyme production is constitutive and thus proportional to biomass, and/or indicated that part of litter decay is independent of enzyme activity. The length and angle of vectors defined by ratios of enzyme activities (BG/NAG versus BG/AP represent relative microbial investments in C (length, and N and P (angle acquiring enzymes. Shorter lengths on day 3 suggested low C limitation, whereas greater lengths on day 14 suggested an increase in C limitation with decay. The soils and litter in this study generally had stronger P limitation (angles > 45˚. Reductions in vector angles to < 45˚ for sand by day 14 suggested a shift to N limitation. These relational variables inform enzyme-based models, and are usually much less ambiguous when obtained from a single study in which measurements were made on the same samples than when extrapolated from separate studies.

  19. Maturation of the Coordination Between Respiration and Deglutition with and Without Recurrent Laryngeal Nerve Lesion in an Animal Model.

    Science.gov (United States)

    Ballester, Ashley; Gould, François; Bond, Laura; Stricklen, Bethany; Ohlemacher, Jocelyn; Gross, Andrew; DeLozier, Katherine; Buddington, Randall; Buddington, Karyl; Danos, Nicole; German, Rebecca

    2018-02-24

    The timing of the occurrence of a swallow in a respiratory cycle is critical for safe swallowing, and changes with infant development. Infants with damage to the recurrent laryngeal nerve, which receives sensory information from the larynx and supplies the intrinsic muscles of the larynx, experience a significant incidence of dysphagia. Using our validated infant pig model, we determined the interaction between this nerve damage and the coordination between respiration and swallowing during postnatal development. We recorded 23 infant pigs at two ages (neonatal and older, pre-weaning) feeding on milk with barium using simultaneous high-speed videofluoroscopy and measurements of thoracic movement. With a complete linear model, we tested for changes with maturation, and whether these changes are the same in control and lesioned individuals. We found (1) the timing of swallowing and respiration coordination changes with maturation; (2) no overall effect of RLN lesion on the timing of coordination, but (3) a greater magnitude of maturational change occurs with RLN injury. We also determined that animals with no surgical intervention did not differ from animals that had surgery for marker placement and a sham procedure for nerve lesion. The coordination between respiration and swallowing changes in normal, intact individuals to provide increased airway protection prior to weaning. Further, in animals with an RLN lesion, the maturation process has a larger effect. Finally, these results suggest a high level of brainstem sensorimotor interactions with respect to these two functions.

  20. Numerical Demons in Monte Carlo Estimation of Bayesian Model Evidence with Application to Soil Respiration Models

    Science.gov (United States)

    Elshall, A. S.; Ye, M.; Niu, G. Y.; Barron-Gafford, G.

    2016-12-01

    Bayesian multimodel inference is increasingly being used in hydrology. Estimating Bayesian model evidence (BME) is of central importance in many Bayesian multimodel analysis such as Bayesian model averaging and model selection. BME is the overall probability of the model in reproducing the data, accounting for the trade-off between the goodness-of-fit and the model complexity. Yet estimating BME is challenging, especially for high dimensional problems with complex sampling space. Estimating BME using the Monte Carlo numerical methods is preferred, as the methods yield higher accuracy than semi-analytical solutions (e.g. Laplace approximations, BIC, KIC, etc.). However, numerical methods are prone the numerical demons arising from underflow of round off errors. Although few studies alluded to this issue, to our knowledge this is the first study that illustrates these numerical demons. We show that the precision arithmetic can become a threshold on likelihood values and Metropolis acceptance ratio, which results in trimming parameter regions (when likelihood function is less than the smallest floating point number that a computer can represent) and corrupting of the empirical measures of the random states of the MCMC sampler (when using log-likelihood function). We consider two of the most powerful numerical estimators of BME that are the path sampling method of thermodynamic integration (TI) and the importance sampling method of steppingstone sampling (SS). We also consider the two most widely used numerical estimators, which are the prior sampling arithmetic mean (AS) and posterior sampling harmonic mean (HM). We investigate the vulnerability of these four estimators to the numerical demons. Interesting, the most biased estimator, namely the HM, turned out to be the least vulnerable. While it is generally assumed that AM is a bias-free estimator that will always approximate the true BME by investing in computational effort, we show that arithmetic underflow can

  1. Imeglimin prevents human endothelial cell death by inhibiting mitochondrial permeability transition without inhibiting mitochondrial respiration

    OpenAIRE

    Detaille, D; Vial, G; Borel, A-L; Cottet-Rouselle, C; Hallakou-Bozec, S; Bolze, S; Fouqueray, P; Fontaine, E

    2016-01-01

    Imeglimin is the first in a new class of oral glucose-lowering agents, having recently completed its phase 2b trial. As Imeglimin did show a full prevention of ?-cell apoptosis, and since angiopathy represents a major complication of diabetes, we studied Imeglimin protective effects on hyperglycemia-induced death of human endothelial cells (HMEC-1). These cells were incubated in several oxidative stress environments (exposure to high glucose and oxidizing agent tert-butylhydroperoxide) which ...

  2. Modeling Soil Organic Carbon Turnover in Four Temperate Forests Based on Radiocarbon Measurements of Heterotrophic Respiration and Soil Organic Carbon

    Science.gov (United States)

    Ahrens, B.; Borken, W.; Muhr, J.; Schrumpf, M.; Savage, K. E.; Wutzler, T.; Trumbore, S.; Reichstein, M.

    2011-12-01

    Soils of temperate forests store significant amounts of soil organic matter and are considered to be net sinks of atmospheric CO2. Soil organic carbon (SOC) dynamics have been studied using the Δ14C signature of bulk SOC or different SOC fractions as observational constraints in SOC models. Further, the Δ14C signature of CO2 evolved during the incubation of soil and roots has been widely used together with Δ14C of total soil respiration to partition soil respiration into heterotrophic respiration (Rh) and root respiration. However, these data have rarely been used together as observational constraints to determine SOC turnover times. Here, we present a multiple constraints approach, where we used SOC stock and its Δ14C signature, and heterotrophic respiration and its Δ14C signature to estimate SOC turnover times of a simple serial two-pool model via Bayesian optimization. We used data from four temperate forest ecosystems in Germany and the USA with different disturbance and management histories from selective logging to afforestation in the late 19th and early 20th century. The Δ14C signature of the atmosphere with its prominent bomb peak was used as a proxy for the Δ14C signature of aboveground and belowground litterfall. The Δ14C signature of litterfall was lagged behind the atmospheric signal to account for the period between photosynthetic fixation of carbon and its addition to SOC pools. We showed that the combined use of Δ14C measurements of Rh and SOC stocks helped to better constrain turnover times of the fast pool (primarily by Δ14C of Rh) and the slow pool (primarily by Δ14C of SOC). In particular, by introducing two additional parameters that describe the deviation from steady state of the fast and slow cycling pool for both SOC and SO14C, we were able to demonstrate that we cannot maintain the often used steady-state assumption of SOC models in general. Furthermore, a new transport version of our model, including SOC transport via

  3. Elimination of Drifts in Long-Duration Monitoring for Apnea-Hypopnea of Human Respiration

    Directory of Open Access Journals (Sweden)

    Peng Jiang

    2016-10-01

    Full Text Available This paper reports a methodology to eliminate an uncertain baseline drift in respiratory monitoring using a thermal airflow sensor exposed in a high humidity environment. Human respiratory airflow usually contains a large amount of moisture (relative humidity, RH > 85%. Water vapors in breathing air condense gradually on the surface of the sensor so as to form a thin water film that leads to a significant sensor drift in long-duration respiratory monitoring. The water film is formed by a combination of condensation and evaporation, and therefore the behavior of the humidity drift is complicated. Fortunately, the exhale and inhale responses of the sensor exhibit distinguishing features that are different from the humidity drift. Using a wavelet analysis method, we removed the baseline drift of the sensor and successfully recovered the respiratory waveform. Finally, we extracted apnea-hypopnea events from the respiratory signals monitored in whole-night sleeps of patients and compared them with golden standard polysomnography (PSG results.

  4. Models of human operators

    International Nuclear Information System (INIS)

    Knee, H.E.; Schryver, J.C.

    1991-01-01

    Models of human behavior and cognition (HB and C) are necessary for understanding the total response of complex systems. Many such models have come available over the past thirty years for various applications. Unfortunately, many potential model users remain skeptical about their practicality, acceptability, and usefulness. Such hesitancy stems in part to disbelief in the ability to model complex cognitive processes, and a belief that relevant human behavior can be adequately accounted for through the use of commonsense heuristics. This paper will highlight several models of HB and C and identify existing and potential applications in attempt to dispel such notions. (author)

  5. Modeling the exergy behavior of human body

    International Nuclear Information System (INIS)

    Keutenedjian Mady, Carlos Eduardo; Silva Ferreira, Maurício; Itizo Yanagihara, Jurandir; Hilário Nascimento Saldiva, Paulo; Oliveira Junior, Silvio de

    2012-01-01

    Exergy analysis is applied to assess the energy conversion processes that take place in the human body, aiming at developing indicators of health and performance based on the concepts of exergy destroyed rate and exergy efficiency. The thermal behavior of the human body is simulated by a model composed of 15 cylinders with elliptical cross section representing: head, neck, trunk, arms, forearms, hands, thighs, legs, and feet. For each, a combination of tissues is considered. The energy equation is solved for each cylinder, being possible to obtain transitory response from the body due to a variation in environmental conditions. With this model, it is possible to obtain heat and mass flow rates to the environment due to radiation, convection, evaporation and respiration. The exergy balances provide the exergy variation due to heat and mass exchange over the body, and the exergy variation over time for each compartments tissue and blood, the sum of which leads to the total variation of the body. Results indicate that exergy destroyed and exergy efficiency decrease over lifespan and the human body is more efficient and destroys less exergy in lower relative humidities and higher temperatures. -- Highlights: ► In this article it is indicated an overview of the human thermal model. ► It is performed the energy and exergy analysis of the human body. ► Exergy destruction and exergy efficiency decreases with lifespan. ► Exergy destruction and exergy efficiency are a function of environmental conditions.

  6. Computational human body models

    NARCIS (Netherlands)

    Wismans, J.S.H.M.; Happee, R.; Dommelen, J.A.W. van

    2005-01-01

    Computational human body models are widely used for automotive crashsafety research and design and as such have significantly contributed to a reduction of traffic injuries and fatalities. Currently crash simulations are mainly performed using models based on crash-dummies. However crash dummies

  7. Leaf photosynthesis and respiration of three bioenergy crops in relation to temperature and leaf nitrogen: how conserved are biochemical model parameters among crop species?

    Science.gov (United States)

    Archontoulis, S V; Yin, X; Vos, J; Danalatos, N G; Struik, P C

    2012-01-01

    Given the need for parallel increases in food and energy production from crops in the context of global change, crop simulation models and data sets to feed these models with photosynthesis and respiration parameters are increasingly important. This study provides information on photosynthesis and respiration for three energy crops (sunflower, kenaf, and cynara), reviews relevant information for five other crops (wheat, barley, cotton, tobacco, and grape), and assesses how conserved photosynthesis parameters are among crops. Using large data sets and optimization techniques, the C(3) leaf photosynthesis model of Farquhar, von Caemmerer, and Berry (FvCB) and an empirical night respiration model for tested energy crops accounting for effects of temperature and leaf nitrogen were parameterized. Instead of the common approach of using information on net photosynthesis response to CO(2) at the stomatal cavity (A(n)-C(i)), the model was parameterized by analysing the photosynthesis response to incident light intensity (A(n)-I(inc)). Convincing evidence is provided that the maximum Rubisco carboxylation rate or the maximum electron transport rate was very similar whether derived from A(n)-C(i) or from A(n)-I(inc) data sets. Parameters characterizing Rubisco limitation, electron transport limitation, the degree to which light inhibits leaf respiration, night respiration, and the minimum leaf nitrogen required for photosynthesis were then determined. Model predictions were validated against independent sets. Only a few FvCB parameters were conserved among crop species, thus species-specific FvCB model parameters are needed for crop modelling. Therefore, information from readily available but underexplored A(n)-I(inc) data should be re-analysed, thereby expanding the potential of combining classical photosynthetic data and the biochemical model.

  8. Leaf photosynthesis and respiration of three bioenergy crops in relation to temperature and leaf nitrogen: how conserved are biochemical model parameters among crop species?

    Science.gov (United States)

    Archontoulis, S. V.; Yin, X.; Vos, J.; Danalatos, N. G.; Struik, P. C.

    2012-01-01

    Given the need for parallel increases in food and energy production from crops in the context of global change, crop simulation models and data sets to feed these models with photosynthesis and respiration parameters are increasingly important. This study provides information on photosynthesis and respiration for three energy crops (sunflower, kenaf, and cynara), reviews relevant information for five other crops (wheat, barley, cotton, tobacco, and grape), and assesses how conserved photosynthesis parameters are among crops. Using large data sets and optimization techniques, the C3 leaf photosynthesis model of Farquhar, von Caemmerer, and Berry (FvCB) and an empirical night respiration model for tested energy crops accounting for effects of temperature and leaf nitrogen were parameterized. Instead of the common approach of using information on net photosynthesis response to CO2 at the stomatal cavity (An–Ci), the model was parameterized by analysing the photosynthesis response to incident light intensity (An–Iinc). Convincing evidence is provided that the maximum Rubisco carboxylation rate or the maximum electron transport rate was very similar whether derived from An–Ci or from An–Iinc data sets. Parameters characterizing Rubisco limitation, electron transport limitation, the degree to which light inhibits leaf respiration, night respiration, and the minimum leaf nitrogen required for photosynthesis were then determined. Model predictions were validated against independent sets. Only a few FvCB parameters were conserved among crop species, thus species-specific FvCB model parameters are needed for crop modelling. Therefore, information from readily available but underexplored An–Iinc data should be re-analysed, thereby expanding the potential of combining classical photosynthetic data and the biochemical model. PMID:22021569

  9. Human migraine models

    DEFF Research Database (Denmark)

    Iversen, Helle Klingenberg

    2001-01-01

    The need for experimental models is obvious. In animal models it is possible to study vascular responses, neurogenic inflammation, c-fos expression etc. However, the pathophysiology of migraine remains unsolved, why results from animal studies not directly can be related to the migraine attack......, which is a human experience. A set-up for investigations of experimental headache and migraine in humans, has been evaluated and headache mechanisms explored by using nitroglycerin and other headache-inducing agents. Nitric oxide (NO) or other parts of the NO activated cascade seems to be responsible...... for the induced headache and migraine. Perspectives are discussed....

  10. Mechanistic model coupling gas exchange dynamics and Listeria monocytogenes growth in modified atmosphere packaging of non respiring food.

    Science.gov (United States)

    Chaix, E; Broyart, B; Couvert, O; Guillaume, C; Gontard, N; Guillard, V

    2015-10-01

    A mechanistic model coupling O2 and CO2 mass transfer (namely diffusion and solubilisation in the food itself and permeation through the packaging material) to microbial growth models was developed aiming at predicting the shelf life of modified atmosphere packaging (MAP) systems. It was experimentally validated on a non-respiring food by investigating concomitantly the O2/CO2 partial pressure in packaging headspace and the growth of Listeria monocytogenes (average microbial count) within the food sample. A sensitivity analysis has revealed that the reliability of the prediction by this "super-parametrized" model (no less than 47 parameters were required for running one simulation) was strongly dependent on the accuracy of the microbial input parameters. Once validated, this model was used to decipher the role of O2/CO2 mass transfer on microbial growth and as a MAP design tool: an example of MAP dimensioning was provided in this paper as a proof of concept. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Predicting soil respiration from peatlands.

    Science.gov (United States)

    Rowson, J G; Worrall, F; Evans, M G; Dixon, S D

    2013-01-01

    This study considers the relative performance of six different models to predict soil respiration from upland peat. Predicting soil respiration is important for global carbon budgets and gap filling measured data from eddy covariance and closed chamber measurements. Further to models previously published new models are presented using two sub-soil zones and season. Models are tested using data from the Bleaklow plateau, southern Pennines, UK. Presented literature models include ANOVA using logged environmental data, the Arrhenius equation, modified versions of the Arrhenius equation to include soil respiration activation energy and water table depth. New models are proposed including the introduction of two soil zones in the peat profile, and season. The first new model proposes a zone of high CO(2) productivity related to increased soil microbial CO(2) production due to the supply of labile carbon from plant root exudates and root respiration. The second zone is a deeper zone where CO(2) production is lower with less labile carbon. A final model allows the zone of high CO(2) production to become dormant during winter months when plants will senesce and will vary depending upon vegetation type within a fixed location. The final model accounted for, on average, 31.9% of variance in net ecosystem respiration within 11 different restoration sites whilst, using the same data set, the best fitting literature equation only accounted for 18.7% of the total variance. Our results demonstrate that soil respiration models can be improved by explicitly accounting for seasonality and the vertically stratified nature of soil processes. These improved models provide an enhanced basis for calculating the peatland carbon budgets which are essential in understanding the role of peatlands in the global C cycle. Copyright © 2012 Elsevier B.V. All rights reserved.

  12. Combined exposure of diesel exhaust particles and respirable Soufrière Hills volcanic ash causes a (pro-)inflammatory response in an in vitro multicellular epithelial tissue barrier model

    Science.gov (United States)

    Tomašek, Ines; Horwell, Claire J.; Damby, David; Barošová, Hana; Geers, Christoph; Petri-Fink, Alke; Rothen-Rutishauser, Barbara; Clift, Martin J. D.

    2016-01-01

    BackgroundThere are justifiable health concerns regarding the potential adverse effects associated with human exposure to volcanic ash (VA) particles, especially when considering communities living in urban areas already exposed to heightened air pollution. The aim of this study was, therefore, to gain an imperative, first understanding of the biological impacts of respirable VA when exposed concomitantly with diesel particles.MethodsA sophisticated in vitro 3D triple cell co-culture model of the human alveolar epithelial tissue barrier was exposed to either a single or repeated dose of dry respirable VA (deposited dose of 0.26 ± 0.09 or 0.89 ± 0.29 μg/cm2, respectively) from Soufrière Hills volcano, Montserrat for a period of 24 h at the air-liquid interface (ALI). Subsequently, co-cultures were exposed to co-exposures of single or repeated VA and diesel exhaust particles (DEP; NIST SRM 2975; 0.02 mg/mL), a model urban pollutant, at the pseudo-ALI. The biological impact of each individual particle type was also analysed under these precise scenarios. The cytotoxic (LDH release), oxidative stress (depletion of intracellular GSH) and (pro-)inflammatory (TNF-α, IL-8 and IL-1β) responses were assessed after the particulate exposures. The impact of VA exposure upon cell morphology, as well as its interaction with the multicellular model, was visualised via confocal laser scanning microscopy (LSM) and scanning electron microscopy (SEM), respectively.ResultsThe combination of respirable VA and DEP, in all scenarios, incited an heightened release of TNF-α and IL-8 as well as significant increases in IL-1β, when applied at sub-lethal doses to the co-culture compared to VA exposure alone. Notably, the augmented (pro-)inflammatory responses observed were not mediated by oxidative stress. LSM supported the quantitative assessment of cytotoxicity, with no changes in cell morphology within the barrier model evident. A direct interaction of the VA with all

  13. Septic Shock Alters Mitochondrial Respiration of Lymphoid Cell-Lines and Human Peripheral Blood Mononuclear Cells: The Role of Plasma.

    Science.gov (United States)

    Clere-Jehl, Raphael; Helms, Julie; Kassem, Mohamad; Le Borgne, Pierrick; Delabranche, Xavier; Charles, Anne-Laure; Geny, Bernard; Meziani, Ferhat; Bilbault, Pascal

    2018-02-14

    In septic shock patients, post-septic immunosuppression state following the systemic inflammatory response syndrome is responsible for nosocomial infections, with subsequent increased mortality. The aim of the present study was to assess the underlying cellular mechanisms of the post-septic immunosuppression state, by investigating mitochondrial functions of peripheral blood mononuclear cells (PBMCs) from septic shock patients over 7 days. Eighteen patients admitted to a French intensive care unit for septic shock were included. At days 1 and 7, PBMCs were isolated by Ficoll density gradient centrifugation. Mitochondrial respiration of intact septic PBMCs was assessed versus control group PBMCs, by measuring O2 consumption in plasma, using high-resolution respirometry. Mitochondrial respiration was then compared between septic plasmas and control plasmas for control PBMCs, septic PBMCs and lymphoid cell-line (CEM). To investigate the role of plasma, we measured several plasma cytokines, among them HMGB1, by ELISA. Basal O2 consumption of septic shock PBMCs was of 8.27 ± 3.39 and 10.48 ± 3.99 pmol/s/10 cells at days 1 and 7 respectively, significantly higher than in control PBMCs (5.37 ± 1.46 pmol/s/10 cells, p Septic patient PBMCs showed a lower response to oligomycin, suggesting a reduced ATP-synthase activity, as well as an increased response to FCCP suggesting an increased mitochondrial respiratory capacity. At 6 hours, septic plasmas showed a decreased O2 consumption of CEM (4.73 ± 1.46 vs. 6.58 ± 1.53, p Septic plasma impairs mitochondrial respiration in immune cells, with a possible role of the proinflammatory protein HMGB1, leading to a subsequent compensation, probably by enzymatic activation. This compensation result is an improvement of global mitochondrial respiratory capacity, but without restoring ATP-synthase activity.

  14. Linear Theory of Soil Organic Carbon Dynamics: Implications in Modeling Soil Respiration and Carbon Sequestration

    Science.gov (United States)

    Porporato, A.; Manzoni, S.; Katul, G.

    2008-12-01

    The long-term, large-scale soil organic carbon dynamics are typically described by mathematical models based on networks of linear reservoirs. Properties of these networks can be diagnosed from linear system theory (i.e. impulse-response transformations), which is seldom used in soil biogeochemistry, although it can be used to compare and test different models in the context of long-term carbon sequestration in soils. In this work, the general theory of linear impulse-response systems is briefly reviewed and linked to the theory of stochastic point processes. Two characteristic times are considered, the residence time (i.e., the time spent by a molecule in the system) and age (the time elapsed since the molecule entered the system). Both are represented through their probability density functions, which are computed explicitly as a function of model structure. Different cases are analyzed and compared, ranging from a simple individual-pool model, to feedback models involving loops (as in models of soil organic carbon-microbial interactions and physical adsorption-desorption), and to more complex networks often used to simulate in the details the soil organic carbon processes. As examples for these complex networks, the compartmental model CENTURY (Parton et al., 1987), and the continuum-quality Q-model (Agren and Bosatta, 1996) are considered. We assess the relative importance of model structural characteristics to determine the organic carbon residence time and age distributions.

  15. Respirator Fact Sheet

    Science.gov (United States)

    ... to protect myself, my family, and/or my employees? If available and used correctly, a respirator can ... Respirator Fact Sheet [PDF - 706 KB] Follow NIOSH Facebook Flickr Pinterest Twitter YouTube NIOSH Homepage NIOSH A- ...

  16. Respirator field performance factors

    International Nuclear Information System (INIS)

    Skaggs, B.J.; DeField, J.D.; Strandberg, S.W.; Sutcliffe, C.R.

    1985-01-01

    The Industrial Hygiene Group assisted OSHA and the NRC in measurements of respirator performance under field conditions. They reviewed problems associated with sampling aerosols within the respirator in order to determine fit factors (FFs) or field performance factor (FPF). In addition, they designed an environmental chamber study to determine the effects of temperature and humidity on a respirator wearer

  17. BMCP1, a novel mitochondrial carrier with high expression in the central nervous system of humans and rodents, and respiration uncoupling activity in recombinant yeast.

    Science.gov (United States)

    Sanchis, D; Fleury, C; Chomiki, N; Goubern, M; Huang, Q; Neverova, M; Grégoire, F; Easlick, J; Raimbault, S; Lévi-Meyrueis, C; Miroux, B; Collins, S; Seldin, M; Richard, D; Warden, C; Bouillaud, F; Ricquier, D

    1998-12-18

    We report here the cloning and functional analysis of a novel homologue of the mitochondrial carriers predominantly expressed in the central nervous system and referred to as BMCP1 (brain mitochondrial carrier protein-1). The predicted amino acid sequence of this novel mitochondrial carrier indicates a level of identity of 39, 31, or 30%, toward the mitochondrial oxoglutarate carrier, phosphate carrier, or adenine nucleotide translocator, respectively, and a level of identity of 34, 38, or 39% with the mitochondrial uncoupling proteins UCP1, UCP2, or UCP3, respectively. Northern analysis of mouse, rat, or human tissues demonstrated that mRNA of this novel gene is mainly expressed in brain, although it is 10-30-fold less expressed in other tissues. In situ hybridization analysis of brain showed it is particularly abundant in cortex, hippocampus, thalamus, amygdala, and hypothalamus. Chromosomal mapping indicates that BMCP1 is located on chromosome X of mice and at Xq24 in man. Expression of the protein in yeast strongly impaired growth rate. Analysis of respiration of total recombinant yeast or yeast spheroplasts and in particular of the relationship between respiratory rate and membrane potential of yeast spheroplasts revealed a marked uncoupling activity of respiration, suggesting that although BMCP1 sequence is more distant from the uncoupling proteins (UCPs), this protein could be a fourth member of the UCP family.

  18. A margin model to account for respiration-induced tumour motion and its variability

    International Nuclear Information System (INIS)

    Coolens, Catherine; Webb, Steve; Evans, Phil M; Shirato, H; Nishioka, K

    2008-01-01

    In order to reduce the sensitivity of radiotherapy treatments to organ motion, compensation methods are being investigated such as gating of treatment delivery, tracking of tumour position, 4D scanning and planning of the treatment, etc. An outstanding problem that would occur with all these methods is the assumption that breathing motion is reproducible throughout the planning and delivery process of treatment. This is obviously not a realistic assumption and is one that will introduce errors. A dynamic internal margin model (DIM) is presented that is designed to follow the tumour trajectory and account for the variability in respiratory motion. The model statistically describes the variation of the breathing cycle over time, i.e. the uncertainty in motion amplitude and phase reproducibility, in a polar coordinate system from which margins can be derived. This allows accounting for an additional gating window parameter for gated treatment delivery as well as minimizing the area of normal tissue irradiated. The model was illustrated with abdominal motion for a patient with liver cancer and tested with internal 3D lung tumour trajectories. The results confirm that the respiratory phases around exhale are most reproducible and have the smallest variation in motion amplitude and phase (approximately 2 mm). More importantly, the margin area covering normal tissue is significantly reduced by using trajectory-specific margins (as opposed to conventional margins) as the angular component is by far the largest contributor to the margin area. The statistical approach to margin calculation, in addition, offers the possibility for advanced online verification and updating of breathing variation as more data become available

  19. Convergence in the temperature response of leaf respiration across biomes and plant functional types.

    Science.gov (United States)

    Heskel, Mary A; O'Sullivan, Odhran S; Reich, Peter B; Tjoelker, Mark G; Weerasinghe, Lasantha K; Penillard, Aurore; Egerton, John J G; Creek, Danielle; Bloomfield, Keith J; Xiang, Jen; Sinca, Felipe; Stangl, Zsofia R; Martinez-de la Torre, Alberto; Griffin, Kevin L; Huntingford, Chris; Hurry, Vaughan; Meir, Patrick; Turnbull, Matthew H; Atkin, Owen K

    2016-04-05

    Plant respiration constitutes a massive carbon flux to the atmosphere, and a major control on the evolution of the global carbon cycle. It therefore has the potential to modulate levels of climate change due to the human burning of fossil fuels. Neither current physiological nor terrestrial biosphere models adequately describe its short-term temperature response, and even minor differences in the shape of the response curve can significantly impact estimates of ecosystem carbon release and/or storage. Given this, it is critical to establish whether there are predictable patterns in the shape of the respiration-temperature response curve, and thus in the intrinsic temperature sensitivity of respiration across the globe. Analyzing measurements in a comprehensive database for 231 species spanning 7 biomes, we demonstrate that temperature-dependent increases in leaf respiration do not follow a commonly used exponential function. Instead, we find a decelerating function as leaves warm, reflecting a declining sensitivity to higher temperatures that is remarkably uniform across all biomes and plant functional types. Such convergence in the temperature sensitivity of leaf respiration suggests that there are universally applicable controls on the temperature response of plant energy metabolism, such that a single new function can predict the temperature dependence of leaf respiration for global vegetation. This simple function enables straightforward description of plant respiration in the land-surface components of coupled earth system models. Our cross-biome analyses shows significant implications for such fluxes in cold climates, generally projecting lower values compared with previous estimates.

  20. Redefinition and global estimation of basal ecosystem respiration rate

    NARCIS (Netherlands)

    Jacobs, C.M.J.; Yuan, W.

    2011-01-01

    Basal ecosystem respiration rate (BR), the ecosystem respiration rate at a given temperature, is a common and important parameter in empirical models for quantifying ecosystem respiration (ER) globally. Numerous studies have indicated that BR varies in space. However, many empirical ER models still

  1. Contribution of aerial hyphae of Aspergillus oryzae to respiration in a model solid-state fermentation system.

    Science.gov (United States)

    Rahardjo, Yovita S P; Weber, Frans J; le Comte, E Paul; Tramper, Johannes; Rinzema, Arjen

    2002-06-05

    Oxygen transfer is for two reasons a major concern in scale-up and process control in industrial application of aerobic fungal solid-state fermentation (SSF): 1) heat production is proportional to oxygen uptake and it is well known that heat removal is one of the main problems in scaled-up fermenters, and 2) oxygen supply to the mycelium on the surface of or inside the substrate particles may be hampered by diffusion limitation. This article gives the first experimental evidence that aerial hyphae are important for fungal respiration in SSF. In cultures of A. oryzae on a wheat-flour model substrate, aerial hyphae contributed up to 75% of the oxygen uptake rate by the fungus. This is due to the fact that A. oryzae forms very abundant aerial mycelium and diffusion of oxygen in the gas-filled pores of the aerial hyphae layer is rapid. It means that diffusion limitation in the densely packed mycelium layer that is formed closer to the substrate surface and that has liquid-filled pores is much less important for A. oryzae than was previously reported for R. oligosporus and C. minitans. It also means that the overall oxygen uptake rate for A. oryzae is much higher than the oxygen uptake rate that can be predicted in the densely packed mycelium layer for R. oligosporus and C. minitans. This would imply that cooling problems become more pronounced. Therefore, it is very important to clarify the physiological role of aerial hyphae in SSF. Copyright 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 78: 539-544, 2002.

  2. Measurements of soil respiration and simple models dependent on moisture and temperature for an Amazonian southwest tropical forest

    NARCIS (Netherlands)

    Zanchi, F.B.; Rocha, Da H.R.; Freitas, De H.C.; Kruijt, B.; Waterloo, M.J.; Manzi, A.O.

    2009-01-01

    Soil respiration plays a significant role in the carbon cycle of Amazonian tropical forests, although in situ measurements have only been poorly reported and the dependence of soil moisture and soil temperature also weakly understood. This work investigates the temporal variability of soil

  3. Integrating Measurements and Models of Water Limitation on Soil and Ecosystem Respiration in Two New England Forests from Hourly to Decadal Timescales.

    Science.gov (United States)

    Sihi, D.; Chen, M.; Davidson, E. A.; Savage, K. E.; Richardson, A. D.; Keenan, T. F.; Hollinger, D. Y.

    2016-12-01

    Soil respiration (SR), the sum of autotrophic (root, Ra) and heterotrophic (microbial, Rh) respiration, is an important component of the global carbon (C) budget and climate change feedbacks from terrestrial ecosystems. Interannual variation of precipitation (and soil moisture) mostly accounts for interannual anomalies in SR. Microbial water stress and limitation of substrate diffusion in dry soil and release from those limitations after a wet-up event also affect SR on short timescales. Variation of precipitation also drives seasonal and interannual patterns of net ecosystem exchange, belowground C allocation, and Ra. Therefore, integration of belowground and aboveground processes is imperative for better understanding of the biosphere-atmosphere C exchange. To that end, we have merged two relatively parsimonious models, a soil enzymatic kinetics model, DAMM (Dual Arrhenius and Michaelis-Menten) and an ecosystem flux model, FöBAAR (Forest Biomass, Assimilation, Allocation and Respiration). We used high-frequency, long-term soil flux data from automated soil chambers and landscape-scale fluxes from eddy covariance towers from the Harvard forest, MA and the Howland forest, ME to develop and validate the merged model and to quantify the uncertainties in a multiple constraints approach. Measurements from trenched and untrenched plots partitioned CO2 flux into Ra and Rh. Preliminary simulations indicated that performance of coupled DAMM- FöBAAR model was improved than FöBAAR-only, as indicated by lower cost functions (model-data mismatch) at the Harvard forest, but not in boreal transition Howland forest, where frequency of droughts is lower due to a shallower water table. Water limitation occurred at Howland, but only briefly and not in most years. Thus, greater confidence in model prediction resulting from inclusion of moisture limitation on substrate availability, an emergent property of DAMM, depends on site conditions, climate, and the temporal scale of

  4. Comparative Risks of Cancer from Drywall Finishing Based on Stochastic Modeling of Cumulative Exposures to Respirable Dusts and Chrysotile Asbestos Fibers.

    Science.gov (United States)

    Boelter, Fred W; Xia, Yulin; Dell, Linda

    2015-05-01

    Sanding joint compounds is a dusty activity and exposures are not well characterized. Until the mid 1970s, asbestos-containing joint compounds were used by some people such that sanding could emit dust and asbestos fibers. We estimated the distribution of 8-h TWA concentrations and cumulative exposures to respirable dusts and chrysotile asbestos fibers for four worker groups: (1) drywall specialists, (2) generalists, (3) tradespersons who are bystanders to drywall finishing, and (4) do-it-yourselfers (DIYers). Data collected through a survey of experienced contractors, direct field observations, and literature were used to develop prototypical exposure scenarios for each worker group. To these exposure scenarios, we applied a previously developed semi-empirical mathematical model that predicts area as well as personal breathing zone respirable dust concentrations. An empirical factor was used to estimate chrysotile fiber concentrations from respirable dust concentrations. On a task basis, we found mean 8-h TWA concentrations of respirable dust and chrysotile fibers are numerically highest for specialists, followed by generalists, DIYers, and bystander tradespersons; these concentrations are estimated to be in excess of the respective current but not historical Threshold Limit Values. Due to differences in frequency of activities, annual cumulative exposures are highest for specialists, followed by generalists, bystander tradespersons, and DIYers. Cumulative exposure estimates for chrysotile fibers from drywall finishing are expected to result in few, if any, mesothelioma or excess lung cancer deaths according to recently published risk assessments. Given the dustiness of drywall finishing, we recommend diligence in the use of readily available source controls. © 2014 Society for Risk Analysis.

  5. Similar qualitative and quantitative changes of mitochondrial respiration following strength and endurance training in normoxia and hypoxia in sedentary humans.

    Science.gov (United States)

    Pesta, Dominik; Hoppel, Florian; Macek, Christian; Messner, Hubert; Faulhaber, Martin; Kobel, Conrad; Parson, Walther; Burtscher, Martin; Schocke, Michael; Gnaiger, Erich

    2011-10-01

    Endurance and strength training are established as distinct exercise modalities, increasing either mitochondrial density or myofibrillar units. Recent research, however, suggests that mitochondrial biogenesis is stimulated by both training modalities. To test the training "specificity" hypothesis, mitochondrial respiration was studied in permeabilized muscle fibers from 25 sedentary adults after endurance (ET) or strength training (ST) in normoxia or hypoxia [fraction of inspired oxygen (Fi(O(2))) = 21% or 13.5%]. Biopsies were taken from the musculus vastus lateralis, and cycle-ergometric incremental maximum oxygen uptake (VO(2max)) exercise tests were performed under normoxia, before and after the 10-wk training program. The main finding was a significant increase (P muscle mass, after endurance and strength training under normoxia [2.6- and 2.4-fold for endurance training normoxia group (ET(N)) and strength training normoxia group (ST(N)); n = 8 and 3] and hypoxia [2.0-fold for the endurance training hypoxia group (ET(H)) and strength training hypoxia group (ST(H)); n = 7 and 7], and higher coupling control of oxidative phosphorylation. The enhanced lipid oxidative phosphorylation (OXPHOS) capacity was mainly (87%) due to qualitative mitochondrial changes increasing the relative capacity for fatty acid oxidation (P muscle mass-specific respiratory capacity with a physiological substrate cocktail (glutamate, malate, succinate, and octanoylcarnitine). No significant increase was observed in mitochondrial DNA (mtDNA) content. Physiological OXPHOS capacity increased significantly in ET(N) (P < 0.01), with the same trend in ET(H) and ST(H) (P < 0.1). The limitation of flux by the phosphorylation system was diminished after training. Importantly, key mitochondrial adaptations were similar after endurance and strength training, regardless of normoxic or hypoxic exercise. The transition from a sedentary to an active lifestyle induced muscular changes of mitochondrial

  6. Mathematical models of human retina.

    Science.gov (United States)

    Tălu, Stefan

    2011-01-01

    To describe the human retina, due the absence of complete topographical data, mathematical models are required. The mathematical formula permits a relatively simple representation to explore the physical and optical characteristics of the retina, with particular parameters. Advanced mathematical models are applied for human vision studies, solid modelling and biomechanical behavior of the retina. The accurate modelling of the retina is important in the development of visual prostheses. The objective of this paper is to present an overview of researches for human retina modelling using mathematical models.

  7. [Factors influencing the variability in soil heterotrophic respiration from terrestrial ecosystem in China].

    Science.gov (United States)

    Xie, Wei; Chen, Shu-Tao; Hu, Zheng-Hua

    2014-01-01

    Soil heterotrophic respiration is one of the key factors for estimating ecosystem carbon balance. Measurement data of soil heterotrophic respiration from terrestrial ecosystem in China were collected. Climate data (annual precipitation and annual mean air temperature) and relevant environmental factors (e. g. tree age) were also collected. Results indicated that the relationship between heterotrophic respiration and soil respiration could be explained by a power function. Heterotrophic respiration increased with the increase of soil respiration. The power function explained 73% of the variability (R2 = 0.730, P power function could be used to explain the relationship between the ratio of heterotrophic respiration to soil respiration and tree age. Further investigation showed that the relationship between measured annual heterotrophic respiration and modeled heterotrophic respiration by using an empirical model could be described by a linear function, indicating that the empirical model well fitted the variability in heterotrophic respiration.

  8. Modeling human color categorization

    NARCIS (Netherlands)

    van den Broek, Egon; Schouten, Th.E.; Kisters, P.M.F.

    A unique color space segmentation method is introduced. It is founded on features of human cognition, where 11 color categories are used in processing color. In two experiments, human subjects were asked to categorize color stimuli into these 11 color categories, which resulted in markers for a

  9. Choosing the right respirator

    International Nuclear Information System (INIS)

    Bidwell, J.

    1997-01-01

    Selecting respirators to help protect workers from airborne contaminants can be a confusing process. The consequences of selecting the incorrect respirator can be intimidating, and worker safety and health may be dramatically and irreparably affected if an inappropriate respirator is chosen. When used in the workplace, a formal respiratory protection program must be established covering the basic requirements outlined in the OSHA Respiratory Protection Standard (29 CFR 1910.134). Education and training must be properly emphasized and conducted periodically. Maintenance, cleaning, and storage programs must be established and routinely followed for reusable respirators. The process of establishing a respiratory protection program can be broken down into four basic steps: Identify respiratory hazards and concentrations; understand the contaminants effects on workers' health; select appropriate respiratory protection; and train in proper respirator use and maintenance. These four steps are the foundation for establishing a basic respirator protection program. Be sure to consult state and federal OSHA requirements to ensure that the program complies. Leading industrial respirator manufacturers should be able to assist with on-site training and education in this four-step process, in addition to helping employers train their workers and conduct respirator fit testing

  10. A UWB Radar Signal Processing Platform for Real-Time Human Respiratory Feature Extraction Based on Four-Segment Linear Waveform Model.

    Science.gov (United States)

    Hsieh, Chi-Hsuan; Chiu, Yu-Fang; Shen, Yi-Hsiang; Chu, Ta-Shun; Huang, Yuan-Hao

    2016-02-01

    This paper presents an ultra-wideband (UWB) impulse-radio radar signal processing platform used to analyze human respiratory features. Conventional radar systems used in human detection only analyze human respiration rates or the response of a target. However, additional respiratory signal information is available that has not been explored using radar detection. The authors previously proposed a modified raised cosine waveform (MRCW) respiration model and an iterative correlation search algorithm that could acquire additional respiratory features such as the inspiration and expiration speeds, respiration intensity, and respiration holding ratio. To realize real-time respiratory feature extraction by using the proposed UWB signal processing platform, this paper proposes a new four-segment linear waveform (FSLW) respiration model. This model offers a superior fit to the measured respiration signal compared with the MRCW model and decreases the computational complexity of feature extraction. In addition, an early-terminated iterative correlation search algorithm is presented, substantially decreasing the computational complexity and yielding negligible performance degradation. These extracted features can be considered the compressed signals used to decrease the amount of data storage required for use in long-term medical monitoring systems and can also be used in clinical diagnosis. The proposed respiratory feature extraction algorithm was designed and implemented using the proposed UWB radar signal processing platform including a radar front-end chip and an FPGA chip. The proposed radar system can detect human respiration rates at 0.1 to 1 Hz and facilitates the real-time analysis of the respiratory features of each respiration period.

  11. Stochastic Models of Human Errors

    Science.gov (United States)

    Elshamy, Maged; Elliott, Dawn M. (Technical Monitor)

    2002-01-01

    Humans play an important role in the overall reliability of engineering systems. More often accidents and systems failure are traced to human errors. Therefore, in order to have meaningful system risk analysis, the reliability of the human element must be taken into consideration. Describing the human error process by mathematical models is a key to analyzing contributing factors. Therefore, the objective of this research effort is to establish stochastic models substantiated by sound theoretic foundation to address the occurrence of human errors in the processing of the space shuttle.

  12. Real-time Modification of Music with Dancer's Respiration Pattern

    OpenAIRE

    Lee, Jeong-seob; Yeo, Woon Seung

    2012-01-01

    This research aims to improve the correspondence between music and dance, and explores the use of human respiration pattern for musical applications with focus on the motional aspect of breathing. While respiration is frequently considered as an indicator of the metabolic state of human body that contains meaningful information for medicine or psychology, motional aspect of respiration has been relatively unnoticed in spite of its strong correlation with muscles and the brain. This paper intr...

  13. Quantitative Respirator Fit, Face Sizes, and Determinants of Fit in South African Diagnostic Laboratory Respirator Users.

    Science.gov (United States)

    Manganyi, Jeanneth; Wilson, Kerry S; Rees, David

    2017-11-10

    Respirators are widely used in health care settings but there is scant information on adequacy of fit and its determinants, particularly in resource-constrained settings. The aim of the study is to describe the proportion of South African diagnostic laboratory respirator users with adequate quantitative respirator fit while wearing their currently selected respirators which were generally supplied without regard to face size, and to identify determinants of fit test pass and fail. This was a cross-sectional study with 562 participants. Quantitative respirator fit testing was conducted using a PortaCount fit testing machine. Four facial dimensions were taken using callipers and a tape measure. STATA 14 was used to perform descriptive and inferential statistics. The effect of the independent variables including face dimensions, race, smoking, respirator make and size, and age group was explored using multiple logistic regression stratified by sex. Ninety one percent of the respirators supplied were medium-sized. Seventy eight percent of respirator users failed fit testing and were thus probably not protected by their currently supplied respirator. Multiple logistic regression analysis showed that face length in mm (odds ratio [OR] = 1.04, 95% confidence interval [CI] = 1.00-1.09), nasal root breadth in mm (OR = 1.16, 95% CI = 1.06-1.28), and respirator shape (OR = 0.56, 95% CI = 0.39-0.78) were significant predictors of overall fit for all subjects and for women alone, but these factors explained only a small percentage of fit test outcomes. A large proportion of diagnostic laboratory employees were using poorly fitting respirators. This creates a false impression of protection. Fit testing of respirators is therefore important and recommended. The determinants evaluated described only a small portion of the variability in fit; important determinants were absent from the models. © The Author 2017. Published by Oxford University Press on behalf of the British

  14. Integrated Environmental Modelling: Human decisions, human challenges

    Science.gov (United States)

    Glynn, Pierre D.

    2015-01-01

    Integrated Environmental Modelling (IEM) is an invaluable tool for understanding the complex, dynamic ecosystems that house our natural resources and control our environments. Human behaviour affects the ways in which the science of IEM is assembled and used for meaningful societal applications. In particular, human biases and heuristics reflect adaptation and experiential learning to issues with frequent, sharply distinguished, feedbacks. Unfortunately, human behaviour is not adapted to the more diffusely experienced problems that IEM typically seeks to address. Twelve biases are identified that affect IEM (and science in general). These biases are supported by personal observations and by the findings of behavioural scientists. A process for critical analysis is proposed that addresses some human challenges of IEM and solicits explicit description of (1) represented processes and information, (2) unrepresented processes and information, and (3) accounting for, and cognizance of, potential human biases. Several other suggestions are also made that generally complement maintaining attitudes of watchful humility, open-mindedness, honesty and transparent accountability. These suggestions include (1) creating a new area of study in the behavioural biogeosciences, (2) using structured processes for engaging the modelling and stakeholder communities in IEM, and (3) using ‘red teams’ to increase resilience of IEM constructs and use.

  15. Integrated Environmental Modelling: human decisions, human challenges

    Science.gov (United States)

    Glynn, Pierre D.

    2015-01-01

    Integrated Environmental Modelling (IEM) is an invaluable tool for understanding the complex, dynamic ecosystems that house our natural resources and control our environments. Human behaviour affects the ways in which the science of IEM is assembled and used for meaningful societal applications. In particular, human biases and heuristics reflect adaptation and experiential learning to issues with frequent, sharply distinguished, feedbacks. Unfortunately, human behaviour is not adapted to the more diffusely experienced problems that IEM typically seeks to address. Twelve biases are identified that affect IEM (and science in general). These biases are supported by personal observations and by the findings of behavioural scientists. A process for critical analysis is proposed that addresses some human challenges of IEM and solicits explicit description of (1) represented processes and information, (2) unrepresented processes and information, and (3) accounting for, and cognizance of, potential human biases. Several other suggestions are also made that generally complement maintaining attitudes of watchful humility, open-mindedness, honesty and transparent accountability. These suggestions include (1) creating a new area of study in the behavioural biogeosciences, (2) using structured processes for engaging the modelling and stakeholder communities in IEM, and (3) using ‘red teams’ to increase resilience of IEM constructs and use.

  16. Convergence in the temperature response of leaf respiration across biomes and plant functional types

    Science.gov (United States)

    Heskel, Mary A.; O’Sullivan, Odhran S.; Reich, Peter B.; Tjoelker, Mark G.; Weerasinghe, Lasantha K.; Penillard, Aurore; Egerton, John J. G.; Creek, Danielle; Bloomfield, Keith J.; Xiang, Jen; Sinca, Felipe; Stangl, Zsofia R.; Martinez-de la Torre, Alberto; Griffin, Kevin L.; Huntingford, Chris; Hurry, Vaughan; Meir, Patrick; Turnbull, Matthew H.; Atkin, Owen K.

    2016-01-01

    Plant respiration constitutes a massive carbon flux to the atmosphere, and a major control on the evolution of the global carbon cycle. It therefore has the potential to modulate levels of climate change due to the human burning of fossil fuels. Neither current physiological nor terrestrial biosphere models adequately describe its short-term temperature response, and even minor differences in the shape of the response curve can significantly impact estimates of ecosystem carbon release and/or storage. Given this, it is critical to establish whether there are predictable patterns in the shape of the respiration–temperature response curve, and thus in the intrinsic temperature sensitivity of respiration across the globe. Analyzing measurements in a comprehensive database for 231 species spanning 7 biomes, we demonstrate that temperature-dependent increases in leaf respiration do not follow a commonly used exponential function. Instead, we find a decelerating function as leaves warm, reflecting a declining sensitivity to higher temperatures that is remarkably uniform across all biomes and plant functional types. Such convergence in the temperature sensitivity of leaf respiration suggests that there are universally applicable controls on the temperature response of plant energy metabolism, such that a single new function can predict the temperature dependence of leaf respiration for global vegetation. This simple function enables straightforward description of plant respiration in the land-surface components of coupled earth system models. Our cross-biome analyses shows significant implications for such fluxes in cold climates, generally projecting lower values compared with previous estimates. PMID:27001849

  17. The development of a model to describe the influence of temperature and relative humidity on respiration rate of prickly pear cactus stems in reduced O2 conditions

    NARCIS (Netherlands)

    Yahia, E.M.; Guevara, J.C.; Beaudry, R.M.; Tijskens, L.M.M.; Cedeno, L.

    2010-01-01

    Respiration rate (RO2) of prickly pear cactus stems (Opuntia spp.) was measured as a function of 4 temperature (T) and 6 relative humidity (RH) combinations for O2 partial pressures between 15 and 0.8 kPa, which were considered to support aerobic respiration. The rate of respiration (RO2) was

  18. Soil respiration partition and its components in the total agro-ecosystem respiration

    Science.gov (United States)

    Delogu, Emilie; LeDantec, Valerie; Mordelet, Patrick; Buysse, Pauline; Aubinet, Marc; Pattey, Elizabeth; Mary, Bruno

    2013-04-01

    Close to 15% of the Earth's terrestrial surface is used for cropland. In the context of global warming, and acknowledged by the Kyoto Protocol, agricultural soils could be a significant sink for atmospheric CO2. Understanding the factors influencing carbon fluxes of agricultural soils is essential for implementing efficient mitigation practices. Most of the soil respiration modeling studies was carried out in forest ecosystems, but only a few was carried out in agricultural ecosystems. In the study, we evaluated simple formalisms to model soil respiration using wheat data from four contrasting geographical mi-latitude regions. Soil respiration were measured in three winter wheat fields at Lamasquère (43°49'N, 01°23'E, 2007) and Auradé (43°54'N, 01°10'E, 2008), South-West France and Lonzée (50°33'N, 4°44'E, 2007), Belgium, and in a spring wheat field at Ottawa (45°22'N, 75°43'W, 2007, 2011), Ontario, Canada. Manual closed chambers were used in the French sites. The Belgium and Canadian sites were equipped with automated closed chamber systems, which continuously collected 30-min soil respiration exchanges. All the sites were also equipped with eddy flux towers. When eddy flux data were collected over bare soil, the net ecosystem exchange (NEE) was equal to soil respiration exchange. These NEE data were used to validate the model. Different biotic and abiotic descriptors were used to model daily soil respiration and its heterotrophic and autotrophic components: soil temperature, soil relative humidity, Gross Primary Productivity (GPP), shoot biomass, crop height, with different formalisms. It was interesting to conclude that using biotic descriptors did not improve the performances of the model. In fact, a combination of abiotic descriptors (soil humidity and soil temperature) allowed significant model formalism to model soil respiration. The simple soil respiration model was used to calculate the heterotrophic and autotrophic source contributions to

  19. Human mobility: Models and applications

    Science.gov (United States)

    Barbosa, Hugo; Barthelemy, Marc; Ghoshal, Gourab; James, Charlotte R.; Lenormand, Maxime; Louail, Thomas; Menezes, Ronaldo; Ramasco, José J.; Simini, Filippo; Tomasini, Marcello

    2018-03-01

    Recent years have witnessed an explosion of extensive geolocated datasets related to human movement, enabling scientists to quantitatively study individual and collective mobility patterns, and to generate models that can capture and reproduce the spatiotemporal structures and regularities in human trajectories. The study of human mobility is especially important for applications such as estimating migratory flows, traffic forecasting, urban planning, and epidemic modeling. In this survey, we review the approaches developed to reproduce various mobility patterns, with the main focus on recent developments. This review can be used both as an introduction to the fundamental modeling principles of human mobility, and as a collection of technical methods applicable to specific mobility-related problems. The review organizes the subject by differentiating between individual and population mobility and also between short-range and long-range mobility. Throughout the text the description of the theory is intertwined with real-world applications.

  20. Frost Induces Respiration and Accelerates Carbon Depletion in Trees.

    Directory of Open Access Journals (Sweden)

    Or Sperling

    Full Text Available Cellular respiration depletes stored carbohydrates during extended periods of limited photosynthesis, e.g. winter dormancy or drought. As respiration rate is largely a function of temperature, the thermal conditions during such periods may affect non-structural carbohydrate (NSC availability and, ultimately, recovery. Here, we surveyed stem responses to temperature changes in 15 woody species. For two species with divergent respirational response to frost, P. integerrima and P. trichocarpa, we also examined corresponding changes in NSC levels. Finally, we simulated respiration-induced NSC depletion using historical temperature data for the western US. We report a novel finding that tree stems significantly increase respiration in response to near freezing temperatures. We observed this excess respiration in 13 of 15 species, deviating 10% to 170% over values predicted by the Arrhenius equation. Excess respiration persisted at temperatures above 0 °C during warming and reoccurred over multiple frost-warming cycles. A large adjustment of NSCs accompanied excess respiration in P. integerrima, whereas P. trichocarpa neither excessively respired nor adjusted NSCs. Over the course of the years included in our model, frost-induced respiration accelerated stem NSC consumption by 8.4 mg (glucose eq. cm(-3 yr(-1 on average in the western US, a level of depletion that may continue to significantly affect spring NSC availability. This novel finding revises the current paradigm of low temperature respiration kinetics.

  1. Global gene expression changes in human embryonic lung fibroblasts induced by organic extracts from respirable air particles

    Directory of Open Access Journals (Sweden)

    Líbalová Helena

    2012-01-01

    Full Text Available Abstract Background Recently, we used cell-free assays to demonstrate the toxic effects of complex mixtures of organic extracts from urban air particles (PM2.5 collected in four localities of the Czech Republic (Ostrava-Bartovice, Ostrava-Poruba, Karvina and Trebon which differed in the extent and sources of air pollution. To obtain further insight into the biological mechanisms of action of the extractable organic matter (EOM from ambient air particles, human embryonic lung fibroblasts (HEL12469 were treated with the same four EOMs to assess changes in the genome-wide expression profiles compared to DMSO treated controls. Method For this purpose, HEL cells were incubated with subtoxic EOM concentrations of 10, 30, and 60 μg EOM/ml for 24 hours and global gene expression changes were analyzed using human whole genome microarrays (Illumina. The expression of selected genes was verified by quantitative real-time PCR. Results Dose-dependent increases in the number of significantly deregulated transcripts as well as dose-response relationships in the levels of individual transcripts were observed. The transcriptomic data did not differ substantially between the localities, suggesting that the air pollution originating mainly from various sources may have similar biological effects. This was further confirmed by the analysis of deregulated pathways and by identification of the most contributing gene modulations. The number of significantly deregulated KEGG pathways, as identified by Goeman's global test, varied, depending on the locality, between 12 to 29. The Metabolism of xenobiotics by cytochrome P450 exhibited the strongest upregulation in all 4 localities and CYP1B1 had a major contribution to the upregulation of this pathway. Other important deregulated pathways in all 4 localities were ABC transporters (involved in the translocation of exogenous and endogenous metabolites across membranes and DNA repair, the Wnt and TGF-β signaling pathways

  2. From breathing to respiration.

    Science.gov (United States)

    Fitting, Jean-William

    2015-01-01

    The purpose of breathing remained an enigma for a long time. The Hippocratic school described breathing patterns but did not associate breathing with the lungs. Empedocles and Plato postulated that breathing was linked to the passage of air through pores of the skin. This was refuted by Aristotle who believed that the role of breathing was to cool the heart. In Alexandria, breakthroughs were accomplished in the anatomy and physiology of the respiratory system. Later, Galen proposed an accurate description of the respiratory muscles and the mechanics of breathing. However, his heart-lung model was hampered by the traditional view of two non-communicating vascular systems - veins and arteries. After a period of stagnation in the Middle Ages, knowledge progressed with the discovery of pulmonary circulation. The comprehension of the purpose of breathing progressed by steps thanks to Boyle and Mayow among others, and culminated with the contribution of Priestley and the discovery of oxygen by Lavoisier. Only then was breathing recognized as fulfilling the purpose of respiration, or gas exchange. A century later, a controversy emerged concerning the active or passive transfer of oxygen from alveoli to the blood. August and Marie Krogh settled the dispute, showing that passive diffusion was sufficient to meet the oxygen needs. © 2014 S. Karger AG, Basel.

  3. A natural human hand model

    NARCIS (Netherlands)

    Van Nierop, O.A.; Van der Helm, A.; Overbeeke, K.J.; Djajadiningrat, T.J.P.

    2007-01-01

    We present a skeletal linked model of the human hand that has natural motion. We show how this can be achieved by introducing a new biology-based joint axis that simulates natural joint motion and a set of constraints that reduce an estimated 150 possible motions to twelve. The model is based on

  4. Low soil moisture during hot periods drives apparent negative temperature sensitivity of soil respiration in a dryland ecosystem: A multi-model comparison

    Science.gov (United States)

    Tucker, Colin; Reed, Sasha C.

    2016-01-01

    Arid and semiarid ecosystems (drylands) may dominate the trajectory of biosphere-to-atmosphere carbon (C) flux over the coming century. Accordingly, understanding dryland CO2 efflux controls is important for understanding C cycling at the global-scale: key unknowns regarding how temperature and moisture interact to regulate dryland C cycling remain. Further, the patchiness of dryland vegetation can create ‘islands of fertility’, with spatially heterogeneous rates of soil respiration (Rs). At our study site in southeastern Utah, USA we added or removed litter (0 to 650% of control) in paired plots that were either associated with a shrub or with interspaces between vascular plants. We measured Rs, soil temperature, and water content (θ) on eight sampling dates between October 2013 and November 2014. Rs was highest following monsoon rains in late summer when soil temperature was ~30°C. During mid-summer, Rs was low, associated with high soil temperatures (>40°C), resulting in an apparent negative temperature sensitivity of Rs at high temperatures, and positive temperature sensitivity at low-moderate temperatures. We used Bayesian statistical methods to compare multiple competing models capturing a wide range of hypothesized relationships between temperature, moisture, and Rs. The best fit model indicates apparent negative temperature sensitivity of soil respiration at high temperatures reflects the control of soil moisture – not high temperatures – in limiting Rs. The modeled Q10 ranged from 2.7 at 5°C to 1.4 at 45°C. Litter addition had no effect on temperature sensitivity or reference respiration (Rref = Rs at 20°C and optimum moisture) beneath shrubs, and little effect on Rref in interspaces, yet Rref was 1.5 times higher beneath shrubs than in interspaces. Together, these results suggest reduced Rs often observed at high temperatures in drylands is dominated by the control of moisture, and that variable litter inputs – at least over the short

  5. Mathematical models of human behavior

    DEFF Research Database (Denmark)

    Møllgaard, Anders Edsberg

    During the last 15 years there has been an explosion in human behavioral data caused by the emergence of cheap electronics and online platforms. This has spawned a whole new research field called computational social science, which has a quantitative approach to the study of human behavior. Most...... studies have considered data sets with just one behavioral variable such as email communication. The Social Fabric interdisciplinary research project is an attempt to collect a more complete data set on human behavior by providing 1000 smartphones with pre-installed data collection software to students...... data set, along with work on other behavioral data. The overall goal is to contribute to a quantitative understanding of human behavior using big data and mathematical models. Central to the thesis is the determination of the predictability of different human activities. Upper limits are derived...

  6. Human Modeling For Ground Processing Human Factors Engineering Analysis

    Science.gov (United States)

    Tran, Donald; Stambolian, Damon; Henderson, Gena; Barth, Tim

    2011-01-01

    There have been many advancements and accomplishments over that last few years using human modeling for human factors engineering analysis for design of spacecraft and launch vehicles. The key methods used for this are motion capture and computer generated human models. The focus of this paper is to explain the different types of human modeling used currently and in the past at Kennedy Space Center (KSC) currently, and to explain the future plans for human modeling for future spacecraft designs.

  7. Dynamics of dissolved oxygen isotopic ratios: a transient model to quantify primary production, community respiration, and air-water exchange in aquatic ecosystems.

    Science.gov (United States)

    Venkiteswaran, Jason J; Wassenaar, Leonard I; Schiff, Sherry L

    2007-08-01

    Dissolved O(2) is an important aquatic ecosystem health indicator. Metabolic and gas exchange (G) rates, which control O(2) concentration, are affected by nutrient loading and other environmental factors. Traditionally, aquatic metabolism has been reported as primary production:community respiration (P:R) ratios using diel measurements and interpretations of dissolved O(2) and/or CO(2) concentrations, and recently using stable isotopes (delta(18)O, Delta(17)O) and steady state assumptions. Aquatic ecosystems, such as rivers and ponds, are not at steady state and exhibit diel changes, so steady state approaches are often inappropriate. A dynamic O(2) stable isotope model (photosynthesis-respiration-gas exchange; PoRGy) is presented here, requiring a minimum of parameters to quantify daily averaged P, R, and G rates under transient field conditions. Unlike steady state approaches, PoRGy can address scenarios with 100% O(2) saturation but with delta(18)O-O(2) values that are not at air equilibrium. PoRGy successfully accounts for isotopic G when applied to an oxygen isotope equilibration laboratory experiment. PoRGy model results closely matched the diel O(2) and delta(18)O-O(2) data from three field sites with different P:R:G ratios and various P, R and G rates. PoRGy provides a new research tool to assess ecosystem health and to pose environmental impact-driven questions. Using daily averaged rates was successful and thus they can be used to compare ecosystems across seasons and landscapes.

  8. Flexible Bayesian Human Fecundity Models.

    Science.gov (United States)

    Kim, Sungduk; Sundaram, Rajeshwari; Buck Louis, Germaine M; Pyper, Cecilia

    2012-12-01

    Human fecundity is an issue of considerable interest for both epidemiological and clinical audiences, and is dependent upon a couple's biologic capacity for reproduction coupled with behaviors that place a couple at risk for pregnancy. Bayesian hierarchical models have been proposed to better model the conception probabilities by accounting for the acts of intercourse around the day of ovulation, i.e., during the fertile window. These models can be viewed in the framework of a generalized nonlinear model with an exponential link. However, a fixed choice of link function may not always provide the best fit, leading to potentially biased estimates for probability of conception. Motivated by this, we propose a general class of models for fecundity by relaxing the choice of the link function under the generalized nonlinear model framework. We use a sample from the Oxford Conception Study (OCS) to illustrate the utility and fit of this general class of models for estimating human conception. Our findings reinforce the need for attention to be paid to the choice of link function in modeling conception, as it may bias the estimation of conception probabilities. Various properties of the proposed models are examined and a Markov chain Monte Carlo sampling algorithm was developed for implementing the Bayesian computations. The deviance information criterion measure and logarithm of pseudo marginal likelihood are used for guiding the choice of links. The supplemental material section contains technical details of the proof of the theorem stated in the paper, and contains further simulation results and analysis.

  9. Plants and Photosynthesis: Level III, Unit 3, Lesson 1; The Human Digestive System: Lesson 2; Functions of the Blood: Lesson 3; Human Circulation and Respiration: Lesson 4; Reproduction of a Single Cell: Lesson 5; Reproduction by Male and Female Cells: Lesson 6; The Human Reproductive System: Lesson 7; Genetics and Heredity: Lesson 8; The Nervous System: Lesson 9; The Glandular System: Lesson 10. Advanced General Education Program. A High School Self-Study Program.

    Science.gov (United States)

    Manpower Administration (DOL), Washington, DC. Job Corps.

    This self-study program for the high-school level contains lessons in the following subjects: Plants and Photosynthesis; The Human Digestive System; Functions of the Blood; Human Circulation and Respiration; Reproduction of a Single Cell; Reproduction by Male and Female Cells; The Human Reproductive System; Genetics and Heredity; The Nervous…

  10. Modelling biased human trust dynamics

    NARCIS (Netherlands)

    Hoogendoorn, M.; Jaffry, S.W.; Maanen, P.P. van; Treur, J.

    2013-01-01

    Abstract. Within human trust related behaviour, according to the literature from the domains of Psychology and Social Sciences often non-rational behaviour can be observed. Current trust models that have been developed typically do not incorporate non-rational elements in the trust formation

  11. Human Resource Models: An Overview.

    Science.gov (United States)

    1982-11-01

    simulation models in which human performance plays an important part see, A.I. Siegel and J.J. Wolf , "Digital Behavioral Simulation--State-of-the-Art...atford and Petersen, Charles C., ’Mfaritine 421-439 Factors Adfecting Iberian Security," (Factores hbritimos Que "Northwestern University, Evanston

  12. Animal models for human diseases.

    Science.gov (United States)

    Rust, J H

    1982-01-01

    The use of animal models for the study of human disease is, for the most part, a recent development. This discussion of the use of animal models for human diseases directs attention to the sterile period, early advances, some personal experiences, the human as the model, biological oddities among common laboratory animals, malignancies in laboratory animals, problems created by federal regulations, cancer tests with animals, and what the future holds in terms of the use of animal models as an aid to understanding human disease. In terms of early use of animal models, there was a school of rabbis, some of whom were also physicians, in Babylon who studied and wrote extensively on ritual slaughter and the suitability of birds and beasts for food. Considerable detailed information on animal pathology, physiology, anatomy, and medicine in general can be found in the Soncino Babylonian Talmudic Translations. The 1906 edition of the "Jewish Encyclopedia," has been a rich resource. Although it has not been possible to establish what diseases of animals were studied and their relationship to the diseases of humans, there are fascinating clues to pursue, despite the fact that these were sterile years for research in medicine. The quotation from the Talmud is of interest: "The medical knowledge of the Talmudist was based upon tradition, the dissection of human bodies, observation of disease and experiments upon animals." A bright light in the lackluster years of medical research was provided by Galen, considered the originator of research in physiology and anatomy. His dissection of animals and work on apes and other lower animals were models for human anatomy and physiology and the bases for many treatises. Yet, Galen never seemed to suggest that animals could serve as models for human diseases. Most early physicians who can be considered to have been students of disease developed their medical knowledge by observing the sick under their care. 1 early medical investigator

  13. Respiration gating and Bloch fitting improve pH measurements with acidoCEST MRI in an ovarian orthotopic tumor model

    Science.gov (United States)

    Jones, Kyle M.; Randtke, Edward A.; Howison, Christine M.; Pagel, Mark D.

    2016-03-01

    We have developed a MRI method that can measure extracellular pH in tumor tissues, known as acidoCEST MRI. This method relies on the detection of Chemical Exchange Saturation Transfer (CEST) of iopamidol, an FDA-approved CT contrast agent that has two CEST signals. A log10 ratio of the two CEST signals is linearly correlated with pH, but independent of agent concentration, endogenous T1 relaxation time, and B1 inhomogeneity. Therefore, detecting both CEST effects of iopamidol during in vivo studies can be used to accurately measure the extracellular pH in tumor tissues. Past in vivo studies using acidoCEST MRI have suffered from respiration artifacts in orthotopic and lung tumor models that have corrupted pH measurements. In addition, the non-linear fitting method used to analyze results is unreliable as it is subject to over-fitting especially with noisy CEST spectra. To improve the technique, we have recently developed a respiration gated CEST MRI pulse sequence that has greatly reduced motion artifacts, and we have included both a prescan and post scan to remove endogenous CEST effects. In addition, we fit the results by parameterizing the contrast of the exogenous agent with respect to pH via the Bloch equations modified for chemical exchange, which is less subject to over-fitting than the non-linear method. These advances in the acidoCEST MRI technique and analysis methods have made pH measurements more reliable, especially in areas of the body subject to respiratory motion.

  14. Plant Respiration and Climate Change Effects

    International Nuclear Information System (INIS)

    Bruhn, D.

    2002-04-01

    Plant respiration is one of the key processes in terms of an understanding of plant growth and functioning in a future climate. Short- and long-term effects of temperature and CO 2 on plant respiration were investigated in a number of plant species. The experiments tested effects of either temperature and/or CO 2 from the level of individual respiratory enzymes, isolated mitochondria, whole-tissue, and up to the whole canopy level. The short-term effects of elevated atmospheric CO 2 on plant respiration appeared to be less than suggested so far in the literature. This was true both at the tissue level and for intact mitochondria. Respiratory enzymes can, however, be affected already at low CO 2 . These effects did not manifest itself at the tissue level, though, due to low degrees of control on the whole respiratory process exerted by the particular enzymes. Plant respiration on the other hand was affected by long-term growth at elevated atmospheric CO 2 . The findings of the reduced plant respiration at the leaf level were consistent with the literature and potential causes are discussed. Short-term effects of temperature on plant respiration were demonstrated to be dependent on the actual measurement temperature. Further, it is shown that mitochondrial leaf respiration in darkness and light differ substantially in the temperature sensitivity with the former being the far most sensitive. This has implications for modelling CO 2 exchange between vegetation and atmosphere as demonstrated here, since this has so far been neglected. Long-term effects of temperature resulted in respiratory acclimation in a number of species. Respiratory acclimation appeared not to occur to any one single type of growth temperature. The implications of this finding in combination with the timing of acclimation are discussed for modelling respiratory CO 2 release. (au)

  15. Plant Respiration and Climate Change Effects

    Energy Technology Data Exchange (ETDEWEB)

    Bruhn, D.

    2002-04-01

    Plant respiration is one of the key processes in terms of an understanding of plant growth and functioning in a future climate. Short- and long-term effects of temperature and CO{sub 2} on plant respiration were investigated in a number of plant species. The experiments tested effects of either temperature and/or CO{sub 2} from the level of individual respiratory enzymes, isolated mitochondria, whole-tissue, and up to the whole canopy level. The short-term effects of elevated atmospheric CO{sub 2} on plant respiration appeared to be less than suggested so far in the literature. This was true both at the tissue level and for intact mitochondria. Respiratory enzymes can, however, be affected already at low CO{sub 2}. These effects did not manifest itself at the tissue level, though, due to low degrees of control on the whole respiratory process exerted by the particular enzymes. Plant respiration on the other hand was affected by long-term growth at elevated atmospheric CO{sub 2}. The findings of the reduced plant respiration at the leaf level were consistent with the literature and potential causes are discussed. Short-term effects of temperature on plant respiration were demonstrated to be dependent on the actual measurement temperature. Further, it is shown that mitochondrial leaf respiration in darkness and light differ substantially in the temperature sensitivity with the former being the far most sensitive. This has implications for modelling CO{sub 2} exchange between vegetation and atmosphere as demonstrated here, since this has so far been neglected. Long-term effects of temperature resulted in respiratory acclimation in a number of species. Respiratory acclimation appeared not to occur to any one single type of growth temperature. The implications of this finding in combination with the timing of acclimation are discussed for modelling respiratory CO{sub 2} release. (au)

  16. A Medical Cloud-Based Platform for Respiration Rate Measurement and Hierarchical Classification of Breath Disorders

    Directory of Open Access Journals (Sweden)

    Atena Roshan Fekr

    2014-06-01

    Full Text Available The measurement of human respiratory signals is crucial in cyberbiological systems. A disordered breathing pattern can be the first symptom of different physiological, mechanical, or psychological dysfunctions. Therefore, a real-time monitoring of the respiration patterns, as well as respiration rate is a critical need in medical applications. There are several methods for respiration rate measurement. However, despite their accuracy, these methods are expensive and could not be integrated in a body sensor network. In this work, we present a real-time cloud-based platform for both monitoring the respiration rate and breath pattern classification, remotely. The proposed system is designed particularly for patients with breathing problems (e.g., respiratory complications after surgery or sleep disorders. Our system includes calibrated accelerometer sensor, Bluetooth Low Energy (BLE and cloud-computing model. We also suggest a procedure to improve the accuracy of respiration rate for patients at rest positions. The overall error in the respiration rate calculation is obtained 0.53% considering SPR-BTA spirometer as the reference. Five types of respiration disorders, Bradapnea, Tachypnea, Cheyn-stokes, Kaussmal, and Biot’s breathing are classified based on hierarchical Support Vector Machine (SVM with seven different features. We have evaluated the performance of the proposed classification while it is individualized to every subject (case 1 as well as considering all subjects (case 2. Since the selection of kernel function is a key factor to decide SVM’s performance, in this paper three different kernel functions are evaluated. The experiments are conducted with 11 subjects and the average accuracy of 94.52% for case 1 and the accuracy of 81.29% for case 2 are achieved based on Radial Basis Function (RBF. Finally, a performance evaluation has been done for normal and impaired subjects considering sensitivity, specificity and G-mean parameters

  17. A medical cloud-based platform for respiration rate measurement and hierarchical classification of breath disorders.

    Science.gov (United States)

    Fekr, Atena Roshan; Janidarmian, Majid; Radecka, Katarzyna; Zilic, Zeljko

    2014-06-24

    The measurement of human respiratory signals is crucial in cyberbiological systems. A disordered breathing pattern can be the first symptom of different physiological, mechanical, or psychological dysfunctions. Therefore, a real-time monitoring of the respiration patterns, as well as respiration rate is a critical need in medical applications. There are several methods for respiration rate measurement. However, despite their accuracy, these methods are expensive and could not be integrated in a body sensor network. In this work, we present a real-time cloud-based platform for both monitoring the respiration rate and breath pattern classification, remotely. The proposed system is designed particularly for patients with breathing problems (e.g., respiratory complications after surgery) or sleep disorders. Our system includes calibrated accelerometer sensor, Bluetooth Low Energy (BLE) and cloud-computing model. We also suggest a procedure to improve the accuracy of respiration rate for patients at rest positions. The overall error in the respiration rate calculation is obtained 0.53% considering SPR-BTA spirometer as the reference. Five types of respiration disorders, Bradapnea, Tachypnea, Cheyn-stokes, Kaussmal, and Biot's breathing are classified based on hierarchical Support Vector Machine (SVM) with seven different features. We have evaluated the performance of the proposed classification while it is individualized to every subject (case 1) as well as considering all subjects (case 2). Since the selection of kernel function is a key factor to decide SVM's performance, in this paper three different kernel functions are evaluated. The experiments are conducted with 11 subjects and the average accuracy of 94.52% for case 1 and the accuracy of 81.29% for case 2 are achieved based on Radial Basis Function (RBF). Finally, a performance evaluation has been done for normal and impaired subjects considering sensitivity, specificity and G-mean parameters of different kernel

  18. Simplified pressure method for respirator fit testing.

    Science.gov (United States)

    Han, D; Xu, M; Foo, S; Pilacinski, W; Willeke, K

    1991-08-01

    A simplified pressure method has been developed for fit testing air-purifying respirators. In this method, the air-purifying cartridges are replaced by a pressure-sensing attachment and a valve. While wearers hold their breath, a small pump extracts air from the respirator cavity until a steady-state pressure is reached in 1 to 2 sec. The flow rate through the face seal leak is a unique function of this pressure, which is determined once for all respirators, regardless of the respirator's cavity volume or deformation because of pliability. The contaminant concentration inside the respirator depends on the degree of dilution by the flow through the cartridges. The cartridge flow varies among different brands and is measured once for each brand. The ratio of cartridge to leakflow is a measure of fit. This flow ratio has been measured on human subjects and has been compared to fit factors determined on the same subjects by means of photometric and particle count tests. The aerosol tests gave higher values of fit.

  19. Macromodel for assessing residential concentrations of combustion-generated pollutants: Model development and preliminary predictions for CO, NO/sub 2/, and respirable suspended particles

    Energy Technology Data Exchange (ETDEWEB)

    Traynor, G.W.; Aceti, J.C.; Apte, M.G.; Smith, B.V.; Green, L.L.; Smith-Reiser, A.; Novak, K.M.; Moses, D.O.

    1989-01-01

    A simulation model (also called a ''macromodel'') has been developed to predict residential air pollutant concentration distributions for specified populations. The model inputs include the market penetration of pollution sources, pollution source characteristics (e.g., emission rates, source usage rates), building characteristics (e.g., house volume, air exchange rates), and meteorological parameters (e.g., outside temperature). Four geographically distinct regions of the US have been modeled using Monte Carlo and deterministic simulation techniques. Single-source simulations were also conducted. The highest predicted CO and NO/sub 2/ residential concentrations were associated with the winter-time use of unvented gas and kerosene space heaters. The highest predicted respirable suspended particulate concentrations were associated with indoor cigarette smoking and the winter-time use of non-airtight wood stoves, radiant kerosene heaters, convective unvented gas space heaters, and oil forced-air furnaces. Future field studies in this area should (1) fill information gaps identified in this report, and (2) collect information on the macromodel input parameters to properly interpret the results. It is almost more important to measure the parameters that affect indoor concentration than it is to measure the concentrations themselves.

  20. Zebrafish models for human cancer.

    Science.gov (United States)

    Shive, H R

    2013-05-01

    For decades, the advancement of cancer research has relied on in vivo models for examining key processes in cancer pathogenesis, including neoplastic transformation, progression, and response to therapy. These studies, which have traditionally relied on rodent models, have engendered a vast body of scientific literature. Recently, experimental cancer researchers have embraced many new and alternative model systems, including the zebrafish (Danio rerio). The general benefits of the zebrafish model for laboratory investigation, such as cost, size, fecundity, and generation time, were quickly superseded by the discovery that zebrafish are amenable to a wide range of investigative techniques, many of which are difficult or impossible to perform in mammalian models. These advantages, coupled with the finding that many aspects of carcinogenesis are conserved in zebrafish as compared with humans, have firmly established a unique niche for the zebrafish model in comparative cancer research. This article introduces methods for generating cancer models in zebrafish and reviews a range of models that have been developed for specific cancer types.

  1. The protozoan, Paramecium primaurelia, as a non-sentient model to test laser light irradiation: The effects of an 808nm infrared laser diode on cellular respiration.

    Science.gov (United States)

    Amaroli, Andrea; Ravera, Silvia; Parker, Steven; Panfoli, Isabella; Benedicenti, Alberico; Benedicenti, Stefano

    2015-07-01

    Photobiomodulation (PBM) has been used in clinical practice for more than 40 years. Unfortunately, conflicting literature has led to the labelling of PBM as a complementary or alternative medicine approach. However, past and ongoing clinical and research studies by reputable investigators have re-established the merits of PBM as a genuine medical therapy, and the technique has, in the last decade, seen an exponential increase in the numbers of clinical instruments available, and their applications. This resurgence has led to a clear need for appropriate experimental models to test the burgeoning laser technology being developed for medical applications. In this context, an ethical model that employs the protozoan, Paramecium primaurelia, is proposed. We studied the possibility of using the measure of oxygen consumption to test PBM by irradiation with an infrared or near-infrared laser. The results show that an 808nm infrared laser diode (1W; 64J/cm²) affects cellular respiration in P. primaurelia, inducing, in the irradiated cells, a significantly (p Paramecium can be an excellent tool in biological assays involving infrared and near-infrared PBM, as it combines the advantages of in vivo results with the practicality of in vitro testing. This test represents a fast, inexpensive and straightforward assay, which offers an alternative to both traditional in vivo testing and more expensive mammalian cellular cultures. 2015 FRAME.

  2. Counseling and Human Sexuality: A Training Model.

    Science.gov (United States)

    Fyfe, Bill

    1980-01-01

    Presents a counseling and human sexuality course model that provides counselors with an information base in human sexuality and assists them in exploring the emotional aspects of sexuality. Human sexuality is a vital aspect of personal development. (Author)

  3. Novel respirable powder formulation: design, aerosolization and permeation studies through pulmonary epithelial cell line and mucus models.

    OpenAIRE

    Stigliani, Mariateresa

    2015-01-01

    2013 - 2014 Direct administration of drugs to the lungs has been used for millennia as a major treatment for a number of diseases. Origin of the inhalation therapies can be found 2000 B.C in India, where people were used to smoke Atropa belladonna leaves to suppress cough. In 1986, researchers at Genentech Inc. (San Francisco, USA) discovered that the hormone of the human growth was naturally absorbed into systemic circulation of rats after its instillation into their lungs. Thus, the ...

  4. Modeling Forces on the Human Body.

    Science.gov (United States)

    Pagonis, Vasilis; Drake, Russel; Morgan, Michael; Peters, Todd; Riddle, Chris; Rollins, Karen

    1999-01-01

    Presents five models of the human body as a mechanical system which can be used in introductory physics courses: human arms as levers, humans falling from small heights, a model of the human back, collisions during football, and the rotating gymnast. Gives ideas for discussions and activities, including Interactive Physics (TM) simulations. (WRM)

  5. Respirable dust and respirable silica exposure in Ontario gold mines.

    Science.gov (United States)

    Verma, Dave K; Rajhans, Gyan S; Malik, Om P; des Tombe, Karen

    2014-01-01

    A comprehensive survey of respirable dust and respirable silica in Ontario gold mines was conducted by the Ontario Ministry of Labor during 1978-1979. The aim was to assess the feasibility of introducing gravimetric sampling to replace the assessment method which used konimeters, a device which gave results in terms of number of particles per cubic centimeter (ppcc) of air. The study involved both laboratory and field assessments. The field assessment involved measurement of airborne respirable dust and respirable silica at all eight operating gold mines of the time. This article describes the details of the field assessment. A total of 288 long-term (7-8 hr) personal respirable dust air samples were collected from seven occupational categories in eight gold mines. The respirable silica (α-quartz) was determined by x-ray diffraction method. The results show that during 1978-1979, the industry wide mean respirable dust was about 1 mg/m(3), and the mean respirable silica was 0.08 mg/m(3.)The mean% silica in respirable dust was 7.5%. The data set would be useful in future epidemiological and health studies, as well as in assessment of workers' compensation claims for occupational diseases such as silicosis, chronic obstructive pulmonary disease (COPD), and autoimmune diseases such as renal disease and rheumatoid arthritis.

  6. Effect of respiration on cardiac filling at rest and during exercise in Fontan patients: A clinical and computational modeling study

    Directory of Open Access Journals (Sweden)

    Alexander Van De Bruaene

    2015-12-01

    Conclusion: In Fontan patients, inspiration resulted in increased ventricular filling at rest and during exercise. Results were confirmed using a computational model indicating a phased time delay between peak SV and peak caval vein flow.

  7. Vicarious Learning from Human Models in Monkeys

    OpenAIRE

    Falcone, Rossella; Brunamonti, Emiliano; Genovesio, Aldo

    2012-01-01

    We examined whether monkeys can learn by observing a human model, through vicarious learning. Two monkeys observed a human model demonstrating an object-reward association and consuming food found underneath an object. The monkeys observed human models as they solved more than 30 learning problems. For each problem, the human models made a choice between two objects, one of which concealed a piece of apple. In the test phase afterwards, the monkeys made a choice of their own. Learning was app...

  8. Deformable human body model development

    Energy Technology Data Exchange (ETDEWEB)

    Wray, W.O.; Aida, T.

    1998-11-01

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). A Deformable Human Body Model (DHBM) capable of simulating a wide variety of deformation interactions between man and his environment has been developed. The model was intended to have applications in automobile safety analysis, soldier survivability studies and assistive technology development for the disabled. To date, we have demonstrated the utility of the DHBM in automobile safety analysis and are currently engaged in discussions with the U.S. military involving two additional applications. More specifically, the DHBM has been incorporated into a Virtual Safety Lab (VSL) for automobile design under contract to General Motors Corporation. Furthermore, we have won $1.8M in funding from the U.S. Army Medical Research and Material Command for development of a noninvasive intracranial pressure measurement system. The proposed research makes use of the detailed head model that is a component of the DHBM; the project duration is three years. In addition, we have been contacted by the Air Force Armstrong Aerospace Medical Research Laboratory concerning possible use of the DHBM in analyzing the loads and injury potential to pilots upon ejection from military aircraft. Current discussions with Armstrong involve possible LANL participation in a comparison between DHBM and the Air Force Articulated Total Body (ATB) model that is the current military standard.

  9. Cattle respiration facility

    DEFF Research Database (Denmark)

    Hellwing, Anne Louise Frydendahl; Lund, Peter; Weisbjerg, Martin Riis

    2012-01-01

    In Denmark, the emission rate of methane from dairy cows has been calculated using the IPCC standard values for dairy cows in Western countries, due to the lack of national data. Therefore, four respiration chambers for dairy cows were built with the main purpose of measuring methane, but also...... for dairy cows is between 800 to 1500 L/min depending on the milk production and liveweight. This gives an average concentration of 5000−6000 ppm of carbon dioxide and 500−600 ppm of methane in the chambers....

  10. Separate and combined effects of a 10-d exposure to hypoxia and inactivity on oxidative function in vivo and mitochondrial respiration ex vivo in humans.

    Science.gov (United States)

    Salvadego, Desy; Keramidas, Michail E; Brocca, Lorenza; Domenis, Rossana; Mavelli, Irene; Rittweger, Jörn; Eiken, Ola; Mekjavic, Igor B; Grassi, Bruno

    2016-07-01

    An integrative evaluation of oxidative metabolism was carried out in 9 healthy young men (age, 24.1 ± 1.7 yr mean ± SD) before (CTRL) and after a 10-day horizontal bed rest carried out in normoxia (N-BR) or hypoxia (H-BR, FiO2 = 0.147). H-BR was designed to simulate planetary habitats. Pulmonary O2 uptake (V̇o2) and vastus lateralis fractional O2 extraction (changes in deoxygenated hemoglobin+myoglobin concentration, Δ[deoxy(Hb+Mb)] evaluated using near-infrared spectroscopy) were evaluated in normoxia and during an incremental cycle ergometer (CE) and one-leg knee extension (KE) exercise (aimed at reducing cardiovascular constraints to oxidative function). Mitochondrial respiration was evaluated ex vivo by high-resolution respirometry in permeabilized vastus lateralis fibers. During CE V̇o2peak and Δ[deoxy(Hb+Mb)]peak were lower (P respiration determined ex vivo was not affected by either intervention. In N-BR, a significant impairment of oxidative metabolism occurred downstream of central cardiovascular O2 delivery and upstream of mitochondrial function, possibly at the level of the intramuscular matching between O2 supply and utilization and peripheral O2 diffusion. Superposition of hypoxia on bed rest did not aggravate, and partially reversed, the impairment of muscle oxidative function in vivo induced by bed rest. The effects of longer exposures will have to be determined. Copyright © 2016 the American Physiological Society.

  11. Vicarious learning from human models in monkeys.

    Science.gov (United States)

    Falcone, Rossella; Brunamonti, Emiliano; Genovesio, Aldo

    2012-01-01

    We examined whether monkeys can learn by observing a human model, through vicarious learning. Two monkeys observed a human model demonstrating an object-reward association and consuming food found underneath an object. The monkeys observed human models as they solved more than 30 learning problems. For each problem, the human models made a choice between two objects, one of which concealed a piece of apple. In the test phase afterwards, the monkeys made a choice of their own. Learning was apparent from the first trial of the test phase, confirming the ability of monkeys to learn by vicarious observation of human models.

  12. Vicarious learning from human models in monkeys.

    Directory of Open Access Journals (Sweden)

    Rossella Falcone

    Full Text Available We examined whether monkeys can learn by observing a human model, through vicarious learning. Two monkeys observed a human model demonstrating an object-reward association and consuming food found underneath an object. The monkeys observed human models as they solved more than 30 learning problems. For each problem, the human models made a choice between two objects, one of which concealed a piece of apple. In the test phase afterwards, the monkeys made a choice of their own. Learning was apparent from the first trial of the test phase, confirming the ability of monkeys to learn by vicarious observation of human models.

  13. Modeling spatial patterns of soil respiration in maize fields from vegetation and soil property factors with the use of remote sensing and geographical information system.

    Science.gov (United States)

    Huang, Ni; Wang, Li; Guo, Yiqiang; Hao, Pengyu; Niu, Zheng

    2014-01-01

    To examine the method for estimating the spatial patterns of soil respiration (Rs) in agricultural ecosystems using remote sensing and geographical information system (GIS), Rs rates were measured at 53 sites during the peak growing season of maize in three counties in North China. Through Pearson's correlation analysis, leaf area index (LAI), canopy chlorophyll content, aboveground biomass, soil organic carbon (SOC) content, and soil total nitrogen content were selected as the factors that affected spatial variability in Rs during the peak growing season of maize. The use of a structural equation modeling approach revealed that only LAI and SOC content directly affected Rs. Meanwhile, other factors indirectly affected Rs through LAI and SOC content. When three greenness vegetation indices were extracted from an optical image of an environmental and disaster mitigation satellite in China, enhanced vegetation index (EVI) showed the best correlation with LAI and was thus used as a proxy for LAI to estimate Rs at the regional scale. The spatial distribution of SOC content was obtained by extrapolating the SOC content at the plot scale based on the kriging interpolation method in GIS. When data were pooled for 38 plots, a first-order exponential analysis indicated that approximately 73% of the spatial variability in Rs during the peak growing season of maize can be explained by EVI and SOC content. Further test analysis based on independent data from 15 plots showed that the simple exponential model had acceptable accuracy in estimating the spatial patterns of Rs in maize fields on the basis of remotely sensed EVI and GIS-interpolated SOC content, with R2 of 0.69 and root-mean-square error of 0.51 µmol CO2 m(-2) s(-1). The conclusions from this study provide valuable information for estimates of Rs during the peak growing season of maize in three counties in North China.

  14. Modeling spatial patterns of soil respiration in maize fields from vegetation and soil property factors with the use of remote sensing and geographical information system.

    Directory of Open Access Journals (Sweden)

    Ni Huang

    Full Text Available To examine the method for estimating the spatial patterns of soil respiration (Rs in agricultural ecosystems using remote sensing and geographical information system (GIS, Rs rates were measured at 53 sites during the peak growing season of maize in three counties in North China. Through Pearson's correlation analysis, leaf area index (LAI, canopy chlorophyll content, aboveground biomass, soil organic carbon (SOC content, and soil total nitrogen content were selected as the factors that affected spatial variability in Rs during the peak growing season of maize. The use of a structural equation modeling approach revealed that only LAI and SOC content directly affected Rs. Meanwhile, other factors indirectly affected Rs through LAI and SOC content. When three greenness vegetation indices were extracted from an optical image of an environmental and disaster mitigation satellite in China, enhanced vegetation index (EVI showed the best correlation with LAI and was thus used as a proxy for LAI to estimate Rs at the regional scale. The spatial distribution of SOC content was obtained by extrapolating the SOC content at the plot scale based on the kriging interpolation method in GIS. When data were pooled for 38 plots, a first-order exponential analysis indicated that approximately 73% of the spatial variability in Rs during the peak growing season of maize can be explained by EVI and SOC content. Further test analysis based on independent data from 15 plots showed that the simple exponential model had acceptable accuracy in estimating the spatial patterns of Rs in maize fields on the basis of remotely sensed EVI and GIS-interpolated SOC content, with R2 of 0.69 and root-mean-square error of 0.51 µmol CO2 m(-2 s(-1. The conclusions from this study provide valuable information for estimates of Rs during the peak growing season of maize in three counties in North China.

  15. Human Performance Modeling for Dynamic Human Reliability Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Boring, Ronald Laurids [Idaho National Laboratory; Joe, Jeffrey Clark [Idaho National Laboratory; Mandelli, Diego [Idaho National Laboratory

    2015-08-01

    Part of the U.S. Department of Energy’s (DOE’s) Light Water Reac- tor Sustainability (LWRS) Program, the Risk-Informed Safety Margin Charac- terization (RISMC) Pathway develops approaches to estimating and managing safety margins. RISMC simulations pair deterministic plant physics models with probabilistic risk models. As human interactions are an essential element of plant risk, it is necessary to integrate human actions into the RISMC risk framework. In this paper, we review simulation based and non simulation based human reliability analysis (HRA) methods. This paper summarizes the founda- tional information needed to develop a feasible approach to modeling human in- teractions in RISMC simulations.

  16. Crowd Human Behavior for Modeling and Simulation

    Science.gov (United States)

    2009-08-06

    Crowd Human Behavior for Modeling and Simulation Elizabeth Mezzacappa, Ph.D. & Gordon Cooke, MEME Target Behavioral Response Laboratory, ARDEC...TYPE Conference Presentation 3. DATES COVERED 00-00-2008 to 00-00-2009 4. TITLE AND SUBTITLE Crowd Human Behavior for Modeling and Simulation...34understanding human behavior " and "model validation and verification" and will focus on modeling and simulation of crowds from a social scientist???s

  17. Biomechanical Modeling of the Human Head

    Science.gov (United States)

    2017-10-03

    Experimental Animal Models for Studies on the Mechanisms of Blast- Induced Neurotrauma,” Frontiers in Neurology 3, 30 (2012). 13. R. A. Bauman, G. Ling...modeling, of both humans and animals , has gained momentum for the investigation of traumatic brain injury. These models require both accurate geometric...between model predictions and experimental data. This report details model calibration for all materials identified in models of a human head and

  18. Development of conformal respirator monitoring technology

    International Nuclear Information System (INIS)

    Shonka, J.J.; Weismann, J.J.; Logan, R.J.

    1997-04-01

    This report summarizes the results of a Small Business Innovative Research Phase II project to develop a modular, surface conforming respirator monitor to improve upon the manual survey techniques presently used by the nuclear industry. Research was performed with plastic scintillator and gas proportional modules in an effort to find the most conducive geometry for a surface conformal, position sensitive monitor. The respirator monitor prototype developed is a computer controlled, position-sensitive detection system employing 56 modular proportional counters mounted in molds conforming to the inner and outer surfaces of a commonly used respirator (Scott Model 801450-40). The molds are housed in separate enclosures and hinged to create a open-quotes waffle-ironclose quotes effect so that the closed monitor will simultaneously survey both surfaces of the respirator. The proportional counter prototype was also designed to incorporate Shonka Research Associates previously developed charge-division electronics. This research provided valuable experience into pixellated position sensitive detection systems. The technology developed can be adapted to other monitoring applications where there is a need for deployment of many traditional radiation detectors

  19. Using eddy covariance of CO2, 13CO2 and CH4, continuous soil respiration measurements, and PhenoCams to constrain a process-based biogeochemical model for carbon market-funded wetland restoration

    Science.gov (United States)

    Oikawa, P. Y.; Baldocchi, D. D.; Knox, S. H.; Sturtevant, C. S.; Verfaillie, J. G.; Dronova, I.; Jenerette, D.; Poindexter, C.; Huang, Y. W.

    2015-12-01

    We use multiple data streams in a model-data fusion approach to reduce uncertainty in predicting CO2 and CH4 exchange in drained and flooded peatlands. Drained peatlands in the Sacramento-San Joaquin River Delta, California are a strong source of CO2 to the atmosphere and flooded peatlands or wetlands are a strong CO2 sink. However, wetlands are also large sources of CH4 that can offset the greenhouse gas mitigation potential of wetland restoration. Reducing uncertainty in model predictions of annual CO2 and CH4 budgets is critical for including wetland restoration in Cap-and-Trade programs. We have developed and parameterized the Peatland Ecosystem Photosynthesis, Respiration, and Methane Transport model (PEPRMT) in a drained agricultural peatland and a restored wetland. Both ecosystem respiration (Reco) and CH4 production are a function of 2 soil carbon (C) pools (i.e. recently-fixed C and soil organic C), temperature, and water table height. Photosynthesis is predicted using a light use efficiency model. To estimate parameters we use a Markov Chain Monte Carlo approach with an adaptive Metropolis-Hastings algorithm. Multiple data streams are used to constrain model parameters including eddy covariance of CO2, 13CO2 and CH4, continuous soil respiration measurements and digital photography. Digital photography is used to estimate leaf area index, an important input variable for the photosynthesis model. Soil respiration and 13CO2 fluxes allow partitioning of eddy covariance data between Reco and photosynthesis. Partitioned fluxes of CO2 with associated uncertainty are used to parametrize the Reco and photosynthesis models within PEPRMT. Overall, PEPRMT model performance is high. For example, we observe high data-model agreement between modeled and observed partitioned Reco (r2 = 0.68; slope = 1; RMSE = 0.59 g C-CO2 m-2 d-1). Model validation demonstrated the model's ability to accurately predict annual budgets of CO2 and CH4 in a wetland system (within 14% and 1

  20. Plankton Respiration from the Cellular to the Basin Scale

    Science.gov (United States)

    Robinson, C.; Garcia-Martin, E. E.; Hull, T.; Kitidis, V. A.; Ostle, C.; Serret, P.; Tilstone, G.

    2016-02-01

    Estimates of marine plankton respiration provide an important constraint on the magnitude of the biological carbon pump and global elemental nutrient cycles, yet respiration remains one of the least constrained terms in models of metabolism, gas exchange and carbon mass balance. This is due in part to the difficulty in measuring both total oceanic respiration and that attributable to specific plankton groups or size classes and the resulting lack of earth observation algorithms. Respiration in the surface layer of the ocean is usually estimated from either the consumption of dissolved oxygen in a contained sample volume or from enzymatic proxies such as INT, and is less frequently determined from mixed layer oxygen utilisation, allometric equations or biomass / abundance spectra.As part of a tracer release (SF6) experiment in the Mauritanian upwelling and a seasonal study of UK shelf sea biogeochemistry, we measured plankton respiration using a range of methods which span time and space scales from cells to the mixed layer and hours to years. This presentation will compare and contrast these concurrent measurements with a view to assessing the range of variability in respiration relative to that in primary production alongside measures of parameters such as plankton community structure and organic carbon availability which may lead to this variability. In addition, by comparing between systems and between seasons in the same system, and utilising the available global dataset, we aim to test predictive empirical models of respiration in an attempt to extrapolate to the basin scale.

  1. Redefinition and global estimation of basal ecosystem respiration rate

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Wenping [College of Global Change and Earth System Science, Beijing Normal University, Beijing, China; Luo, Yiqi [Department of Botany and Microbiology, University of Oklahoma, Norman, Oklahoma, USA; Li, Xianglan [College of Global Change and Earth System Science, Beijing Normal University, Beijing, China; Liu, Shuguang; Yu, Guirui [Key Laboratory of Ecosystem Network Observation and Modeling, Synthesis Research Center of Chinese Ecosystem Research Network, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China; Zhou, Tao [State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing, China; Bahn, Michael [Institute of Ecology, University of Innsbruck, Innsbruck, Austria; Black, Andy [Faculty of Land and Food Systems, University of British Columbia, Vancouver, B. C., Canada; Desai, Ankur R. [Atmospheric and Oceanic Sciences Department, Center for Climatic Research, Nelson Institute for Environmental Studies, University of Wisconsin-Madison, Madison, Wisconsin, USA; Cescatti, Alessandro [Institute for Environment and Sustainability, Joint Research Centre, European Commission, Ispra, Italy; Marcolla, Barbara [Sustainable Agro-ecosystems and Bioresources Department, Fondazione Edmund Mach-IASMA Research and Innovation Centre, San Michele all' Adige, Italy; Jacobs, Cor [Alterra, Earth System Science-Climate Change, Wageningen University, Wageningen, Netherlands; Chen, Jiquan [Department of Earth, Ecological, and Environmental Sciences, University of Toledo, Toledo, Ohio, USA; Aurela, Mika [Climate and Global Change Research, Finnish Meteorological Institute, Helsinki, Finland; Bernhofer, Christian [Chair of Meteorology, Institute of Hydrology and Meteorology, Technische Universität Dresden, Dresden, Germany; Gielen, Bert [Department of Biology, University of Antwerp, Wilrijk, Belgium; Bohrer, Gil [Department of Civil, Environmental, and Geodetic Engineering, Ohio State University, Columbus, Ohio, USA; Cook, David R. [Climate Research Section, Environmental Science Division, Argonne National Laboratory, Argonne, Illinois, USA; Dragoni, Danilo [Department of Geography, Indiana University, Bloomington, Indiana, USA; Dunn, Allison L. [Department of Physical and Earth Sciences, Worcester State College, Worcester, Massachusetts, USA; Gianelle, Damiano [Sustainable Agro-ecosystems and Bioresources Department, Fondazione Edmund Mach-IASMA Research and Innovation Centre, San Michele all' Adige, Italy; Grünwald, Thomas [Chair of Meteorology, Institute of Hydrology and Meteorology, Technische Universität Dresden, Dresden, Germany; Ibrom, Andreas [Risø DTU National Laboratory for Sustainable Energy, Biosystems Division, Technical University of Denmark, Roskilde, Denmark; Leclerc, Monique Y. [Department of Crop and Soil Sciences, College of Agricultural and Environmental Sciences, University of Georgia, Griffin, Georgia, USA; Lindroth, Anders [Geobiosphere Science Centre, Physical Geography and Ecosystems Analysis, Lund University, Lund, Sweden; Liu, Heping [Laboratory for Atmospheric Research, Department of Civil and Environmental Engineering, Washington State University, Pullman, Washington, USA; Marchesini, Luca Belelli [Department for Innovation in Biological, Agro-Food and Forest Systems, University of Tuscia, Viterbo, Italy; Montagnani, Leonardo; Pita, Gabriel [Department of Mechanical Engineering, Instituto Superior Técnico, Lisbon, Portugal; Rodeghiero, Mirco [Sustainable Agro-ecosystems and Bioresources Department, Fondazione Edmund Mach-IASMA Research and Innovation Centre, San Michele all' Adige, Italy; Rodrigues, Abel [Unidade de Silvicultura e Produtos Florestais, Instituto Nacional dos Recursos Biológicos, Oeiras, Portugal; Starr, Gregory [Department of Biological Sciences, University of Alabama, Tuscaloosa, Alabama, USA; Stoy, Paul C. [Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, Montana, USA

    2011-10-13

    Basal ecosystem respiration rate (BR), the ecosystem respiration rate at a given temperature, is a common and important parameter in empirical models for quantifying ecosystem respiration (ER) globally. Numerous studies have indicated that BR varies in space. However, many empirical ER models still use a global constant BR largely due to the lack of a functional description for BR. In this study, we redefined BR to be ecosystem respiration rate at the mean annual temperature. To test the validity of this concept, we conducted a synthesis analysis using 276 site-years of eddy covariance data, from 79 research sites located at latitudes ranging from ~3°S to ~70°N. Results showed that mean annual ER rate closely matches ER rate at mean annual temperature. Incorporation of site-specific BR into global ER model substantially improved simulated ER compared to an invariant BR at all sites. These results confirm that ER at the mean annual

  2. Ecosystem respiration depends strongly on photosynthesis in a temperate heath

    DEFF Research Database (Denmark)

    Larsen, Klaus Steenberg; Ibrom, A.; Beier, C.

    2007-01-01

    We measured net ecosystem CO2 flux (F-n) and ecosystem respiration (R-E), and estimated gross ecosystem photosynthesis (P-g) by difference, for two years in a temperate heath ecosystem using a chamber method. The exchange rates of carbon were high and of similar magnitude as for productive forest...... respiration from October to March was 22% and 30% of annual flux, respectively, suggesting that both cold-season carbon gain and loss were important in the annual carbon cycle of the ecosystem. Model fit of R-E of a classic, first-order exponential equation related to temperature ( second year; R-2 = 0......) of 2.5 by the modified model. The model introduces R-photo, which describes the part of respiration being tightly coupled to the photosynthetic rate. It makes up 5% of the assimilated carbon dioxide flux at 0 degrees C and 35% at 20 degrees C implying a high sensitivity of respiration to photosynthesis...

  3. Human mammary microenvironment better regulates the biology of human breast cancer in humanized mouse model.

    Science.gov (United States)

    Zheng, Ming-Jie; Wang, Jue; Xu, Lu; Zha, Xiao-Ming; Zhao, Yi; Ling, Li-Jun; Wang, Shui

    2015-02-01

    During the past decades, many efforts have been made in mimicking the clinical progress of human cancer in mouse models. Previously, we developed a human breast tissue-derived (HB) mouse model. Theoretically, it may mimic the interactions between "species-specific" mammary microenvironment of human origin and human breast cancer cells. However, detailed evidences are absent. The present study (in vivo, cellular, and molecular experiments) was designed to explore the regulatory role of human mammary microenvironment in the progress of human breast cancer cells. Subcutaneous (SUB), mammary fat pad (MFP), and HB mouse models were developed for in vivo comparisons. Then, the orthotopic tumor masses from three different mouse models were collected for primary culture. Finally, the biology of primary cultured human breast cancer cells was compared by cellular and molecular experiments. Results of in vivo mouse models indicated that human breast cancer cells grew better in human mammary microenvironment. Cellular and molecular experiments confirmed that primary cultured human breast cancer cells from HB mouse model showed a better proliferative and anti-apoptotic biology than those from SUB to MFP mouse models. Meanwhile, primary cultured human breast cancer cells from HB mouse model also obtained the migratory and invasive biology for "species-specific" tissue metastasis to human tissues. Comprehensive analyses suggest that "species-specific" mammary microenvironment of human origin better regulates the biology of human breast cancer cells in our humanized mouse model of breast cancer, which is more consistent with the clinical progress of human breast cancer.

  4. Discovery and therapeutic potential of drugs that shift energy metabolism from mitochondrial respiration to glycolysis

    Science.gov (United States)

    Gohil, Vishal M.; Sheth, Sunil A.; Nilsson, Roland; Wojtovich, Andrew P.; Lee, Jeong Hyun; Perocchi, Fabiana; Chen, William; Clish, Clary B.; Ayata, Cenk; Brookes, Paul S.; Mootha, Vamsi K.

    2010-01-01

    Most cells can dynamically shift their relative reliance on glycolytic versus oxidative metabolism in response to nutrient availability, during development, and in disease. Studies in model systems have shown that re-directing energy metabolism from respiration to glycolysis can suppress oxidative damage and cell death in ischemic injury. At present we have a limited set of drugs that safely toggle energy metabolism in humans. Here, we introduce a quantitative, nutrient sensitized screening strategy that can identify such compounds based on their ability to selectively impair growth and viability of cells grown in galactose versus glucose. We identify several FDA approved agents never before linked to energy metabolism, including meclizine, which blunts cellular respiration via a mechanism distinct from canonical inhibitors. We further show that meclizine pretreatment confers cardioprotection and neuroprotection against ischemia-reperfusion injury in murine models. Nutrient-sensitized screening may offer a useful framework for understanding gene function and drug action within the context of energy metabolism. PMID:20160716

  5. On scaling of human body models

    Directory of Open Access Journals (Sweden)

    Hynčík L.

    2007-10-01

    Full Text Available Human body is not an unique being, everyone is another from the point of view of anthropometry and mechanical characteristics which means that division of the human body population to categories like 5%-tile, 50%-tile and 95%-tile from the application point of view is not enough. On the other hand, the development of a particular human body model for all of us is not possible. That is why scaling and morphing algorithms has started to be developed. The current work describes the development of a tool for scaling of the human models. The idea is to have one (or couple of standard model(s as a base and to create other models based on these basic models. One has to choose adequate anthropometrical and biomechanical parameters that describe given group of humans to be scaled and morphed among.

  6. Computer modeling of human decision making

    Science.gov (United States)

    Gevarter, William B.

    1991-01-01

    Models of human decision making are reviewed. Models which treat just the cognitive aspects of human behavior are included as well as models which include motivation. Both models which have associated computer programs, and those that do not, are considered. Since flow diagrams, that assist in constructing computer simulation of such models, were not generally available, such diagrams were constructed and are presented. The result provides a rich source of information, which can aid in construction of more realistic future simulations of human decision making.

  7. Soil Respiration in Semiarid Temperate Grasslands under Various Land Management.

    Science.gov (United States)

    Wang, Zhen; Ji, Lei; Hou, Xiangyang; Schellenberg, Michael P

    2016-01-01

    Soil respiration, a major component of the global carbon cycle, is significantly influenced by land management practices. Grasslands are potentially a major sink for carbon, but can also be a source. Here, we investigated the potential effect of land management (grazing, clipping, and ungrazed enclosures) on soil respiration in the semiarid grassland of northern China. Our results showed the mean soil respiration was significantly higher under enclosures (2.17 μmol.m(-2).s(-1)) and clipping (2.06 μmol.m(-2).s(-1)) than under grazing (1.65 μmol.m-(2).s(-1)) over the three growing seasons. The high rates of soil respiration under enclosure and clipping were associated with the higher belowground net primary productivity (BNPP). Our analyses indicated that soil respiration was primarily related to BNPP under grazing, to soil water content under clipping. Using structural equation models, we found that soil water content, aboveground net primary productivity (ANPP) and BNPP regulated soil respiration, with soil water content as the predominant factor. Our findings highlight that management-induced changes in abiotic (soil temperature and soil water content) and biotic (ANPP and BNPP) factors regulate soil respiration in the semiarid temperate grassland of northern China.

  8. Soil Respiration in Semiarid Temperate Grasslands under Various Land Management.

    Directory of Open Access Journals (Sweden)

    Zhen Wang

    Full Text Available Soil respiration, a major component of the global carbon cycle, is significantly influenced by land management practices. Grasslands are potentially a major sink for carbon, but can also be a source. Here, we investigated the potential effect of land management (grazing, clipping, and ungrazed enclosures on soil respiration in the semiarid grassland of northern China. Our results showed the mean soil respiration was significantly higher under enclosures (2.17 μmol.m(-2.s(-1 and clipping (2.06 μmol.m(-2.s(-1 than under grazing (1.65 μmol.m-(2.s(-1 over the three growing seasons. The high rates of soil respiration under enclosure and clipping were associated with the higher belowground net primary productivity (BNPP. Our analyses indicated that soil respiration was primarily related to BNPP under grazing, to soil water content under clipping. Using structural equation models, we found that soil water content, aboveground net primary productivity (ANPP and BNPP regulated soil respiration, with soil water content as the predominant factor. Our findings highlight that management-induced changes in abiotic (soil temperature and soil water content and biotic (ANPP and BNPP factors regulate soil respiration in the semiarid temperate grassland of northern China.

  9. Comparison and significance of respiration and glycolysis of prostatic tissue from various species.

    Science.gov (United States)

    Müntzing, J; Varkarakis, M J; Saroff, J; Murphy, G P

    1975-01-01

    The respiration and glycolysis of prostatic tissue from baboons, rhesus monkeys, dogs and rats were compared to the respiration and glycolysis in human prostatic tissue. All the primate prostates had a high glycolytic ability and a low respiration in contrast to the rat and dog prostate. Treatment of baboons with drugs clinically effective against prostatic cancer did not change the prostatic metabolism despite a marked prostatic atrophy. In vitro the drugs reduced respiration markedly. The metabolic similarity between the human and the baboon and rhesus monkey prostate indicates that nonhuman primates should be investigated in the evaluation of chemotherapeutic agents for treatment of prostatic cancer.

  10. Human Performance Models of Pilot Behavior

    Science.gov (United States)

    Foyle, David C.; Hooey, Becky L.; Byrne, Michael D.; Deutsch, Stephen; Lebiere, Christian; Leiden, Ken; Wickens, Christopher D.; Corker, Kevin M.

    2005-01-01

    Five modeling teams from industry and academia were chosen by the NASA Aviation Safety and Security Program to develop human performance models (HPM) of pilots performing taxi operations and runway instrument approaches with and without advanced displays. One representative from each team will serve as a panelist to discuss their team s model architecture, augmentations and advancements to HPMs, and aviation-safety related lessons learned. Panelists will discuss how modeling results are influenced by a model s architecture and structure, the role of the external environment, specific modeling advances and future directions and challenges for human performance modeling in aviation.

  11. Animal models for human genetic diseases

    African Journals Online (AJOL)

    Sharif Sons

    to be the prime model of inherited human disease and share 99% of their ... disturbances (including anxiety and depression) ..... Leibovici M, Safieddine S, Petit C (2008). Mouse models for human hereditary deafness. Curr. Top. Dev. Biol. 84:385-429. Levi YF, Meiner Z, Canello T, Frid K, Kovacs GG, Budka H, Avrahami.

  12. Plant respiration under low oxygen

    Directory of Open Access Journals (Sweden)

    Guillermo Toro

    2015-08-01

    Full Text Available Respiration is an oxidative process controlled by three pathways: glycolysis, the tricarboxylic acid (TCA cycle, and oxidative phosphorylation (OXPHOS. Respiratory metabolism is ubiquitous in all organisms, but with differences among each other. For example in plants, because their high plasticity, respiration involves metabolic pathways with unique characteristics. In this way, in order to avoid states of low energy availability, plants exhibit great flexibility to bypass conventional steps of glycolysis, TCA cycle, and OXPHOS. To understand the energetic link between these alternative pathways, it is important to know the growth, maintenance, and ion uptake components of the respiration in plants. Changes in these components have been reported when plants are subjected to stress, such as oxygen deficiency. This review analyzes the current knowledge on the metabolic and functional aspects of plant respiration, its components and its response to environmental changes.

  13. Secondary metabolites of the grapevine pathogen Eutypa lata inhibit mitochondrial respiration, based on a model bioassay using the yeast Saccharomyces cerevisiae.

    Science.gov (United States)

    Kim, Jong H; Mahoney, Noreen; Chan, Kathleen L; Molyneux, Russell J; Campbell, Bruce C

    2004-10-01

    Acetylenic phenols and a chromene isolated from the grapevine fungal pathogen Eutypa lata were examined for mode of toxicity. The compounds included eutypine (4-hydroxy-3-[3-methyl-3-butene-1-ynyl] benzyl aldehyde), eutypinol (4-hydroxy-3-[3-methyl-3-butene-1-ynyl] benzyl alcohol), eulatachromene, 2- isoprenyl-5-formyl-benzofuran, siccayne, and eulatinol. A bioassay using the yeast Saccharomyces cerevisiae showed that all compounds were either lethal or inhibited growth. A respiratory assay using 2,3,5-triphenyltetrazolium (TTC) indicated that eutypinol and eulatachromene inhibited mitochondrial respiration in wild-type yeast. Bioassays also showed that 2- isoprenyl-5-formyl-benzofuran and siccayne inhibited mitochondrial respiration in the S. cerevisiae deletion mutant vph2Delta, lacking a vacuolar type H (+) ATPase (V-ATPase) assembly protein. Cell growth of tsa1Delta, a deletion mutant of S. cerevisiae lacking a thioredoxin peroxidase (cTPx I), was greatly reduced when grown on media containing eutypinol or eulatachromene and exposed to hydrogen peroxide (H(2)O(2)) as an oxidative stress. This reduction in growth establishes the toxic mode of action of these compounds through inhibition of mitochondrial respiration.

  14. Mitochondrial Respiration and Oxygen Tension.

    Science.gov (United States)

    Shaw, Daniel S; Meitha, Karlia; Considine, Michael J; Foyer, Christine H

    2017-01-01

    Measurements of respiration and oxygen tension in plant organs allow a precise understanding of mitochondrial capacity and function within the context of cellular oxygen metabolism. Here we describe methods that can be routinely used for the isolation of intact mitochondria, and the determination of respiratory electron transport, together with techniques for in vivo determination of oxygen tension and measurement of respiration by both CO 2 production and O 2 consumption that enables calculation of the respiratory quotient [CO 2 ]/[O 2 ].

  15. Hidden Markov Models for Human Genes

    DEFF Research Database (Denmark)

    Baldi, Pierre; Brunak, Søren; Chauvin, Yves

    1997-01-01

    We analyse the sequential structure of human genomic DNA by hidden Markov models. We apply models of widely different design: conventional left-right constructs and models with a built-in periodic architecture. The models are trained on segments of DNA sequences extracted such that they cover com...

  16. Surfactants and the Mechanics of Respiration

    Science.gov (United States)

    Jbaily, Abdulrahman; Szeri, Andrew J.

    2016-11-01

    Alveoli are small sacs found at the end of terminal bronchioles in human lungs with a mean diameter of 200 μm. A thin layer of fluid (hypophase) coats the inner face of an alveolus and is in contact with the air in the lungs. The thickness of this layer varies among alveoli, but is in the range of 0.1 to 0.5 μm for many portions of the alveolar network. The interfacial tension σ at the air-hypophase interface tends to favor collapse of the alveolus, and resists its expansion during inhalation. Type II alveolar cells synthesize and secrete a mixture of phospholipids and proteins called pulmonary surfactant. These surfactant molecules adsorb to the interface causing σ of water at body temperature is 70 mN/m and falls to an equilibrium value of 25 mN/m when surfactants are present. Also, in a dynamic sense, it is known that σ is reduced to near 0 during exhalation when the surfactant film compresses. In this work, the authors develop a mechanical and transport model of the alveolus to study the effect of surfactants on various aspects of respiration. The model is composed of three principal parts: (i) air movement into and out of the alveolus; (ii) a balance of linear momentum across the two-layered membrane of the alveolus (hypophase and elastic wall); and (iii) a pulmonary surfactant transport problem in the hypophase. The goal is to evaluate the influence of pulmonary surfactant on respiratory mechanics.

  17. Contribution of root respiration to soil respiration in a C3/C4 mixed ...

    Indian Academy of Sciences (India)

    The spatial and temporal variations of soil respiration were studied from May 2004 to June 2005 in a C3/C4 mixed grassland of Japan. The linear regression relationship between soil respiration and root biomass was used to determine the contribution of root respiration to soil respiration. The highest soil respiration rate of ...

  18. Contribution of root respiration to soil respiration in a C3/C4 mixed ...

    Indian Academy of Sciences (India)

    Unknown

    The spatial and temporal variations of soil respiration were studied from May 2004 to June 2005 in a C3/C4 mixed grassland of Japan. The linear regression relationship between soil respiration and root biomass was used to determine the contribution of root respiration to soil respiration. The highest soil respiration rate of.

  19. Cardiac, skeletal, and smooth muscle mitochondrial respiration: are all mitochondria created equal?

    OpenAIRE

    Park, Song-Young; Gifford, Jayson R.; Andtbacka, Robert H. I.; Trinity, Joel D.; Hyngstrom, John R.; Garten, Ryan S.; Diakos, Nikolaos A.; Ives, Stephen J.; Dela, Flemming; Larsen, Steen; Drakos, Stavros; Richardson, Russell S.

    2014-01-01

    Unlike cardiac and skeletal muscle, little is known about vascular smooth muscle mitochondrial respiration. Therefore, the present study examined mitochondrial respiratory rates in smooth muscle of healthy human feed arteries and compared with that of healthy cardiac and skeletal muscles. Cardiac, skeletal, and smooth muscles were harvested from a total of 22 subjects (53 ± 6 yr), and mitochondrial respiration was assessed in permeabilized fibers. Complex I + II, state 3 respiration, an index...

  20. Human Centered Hardware Modeling and Collaboration

    Science.gov (United States)

    Stambolian Damon; Lawrence, Brad; Stelges, Katrine; Henderson, Gena

    2013-01-01

    In order to collaborate engineering designs among NASA Centers and customers, to in clude hardware and human activities from multiple remote locations, live human-centered modeling and collaboration across several sites has been successfully facilitated by Kennedy Space Center. The focus of this paper includes innovative a pproaches to engineering design analyses and training, along with research being conducted to apply new technologies for tracking, immersing, and evaluating humans as well as rocket, vehic le, component, or faci lity hardware utilizing high resolution cameras, motion tracking, ergonomic analysis, biomedical monitoring, wor k instruction integration, head-mounted displays, and other innovative human-system integration modeling, simulation, and collaboration applications.

  1. Nitric oxide and mitochondrial respiration.

    Science.gov (United States)

    Brown, G C

    1999-05-05

    Nitric oxide (NO) and its derivative peroxynitrite (ONOO-) inhibit mitochondrial respiration by distinct mechanisms. Low (nanomolar) concentrations of NO specifically inhibit cytochrome oxidase in competition with oxygen, and this inhibition is fully reversible when NO is removed. Higher concentrations of NO can inhibit the other respiratory chain complexes, probably by nitrosylating or oxidising protein thiols and removing iron from the iron-sulphur centres. Peroxynitrite causes irreversible inhibition of mitochondrial respiration and damage to a variety of mitochondrial components via oxidising reactions. Thus peroxynitrite inhibits or damages mitochondrial complexes I, II, IV and V, aconitase, creatine kinase, the mitochondrial membrane, mitochondrial DNA, superoxide dismutase, and induces mitochondrial swelling, depolarisation, calcium release and permeability transition. The NO inhibition of cytochrome oxidase may be involved in the physiological regulation of respiration rate, as indicated by the finding that isolated cells producing NO can regulate cellular respiration by this means, and the finding that inhibition of NO synthase in vivo causes a stimulation of tissue and whole body oxygen consumption. The recent finding that mitochondria may contain a NO synthase and can produce significant amounts of NO to regulate their own respiration also suggests this regulation may be important for physiological regulation of energy metabolism. However, definitive evidence that NO regulation of mitochondrial respiration occurs in vivo is still missing, and interpretation is complicated by the fact that NO appears to affect tissue respiration by cGMP-dependent mechanisms. The NO inhibition of cytochrome oxidase may also be involved in the cytotoxicity of NO, and may cause increased oxygen radical production by mitochondria, which may in turn lead to the generation of peroxynitrite. Mitochondrial damage by peroxynitrite may mediate the cytotoxicity of NO, and may be

  2. Human Adaptive Mechatronics and Human-System Modelling

    Directory of Open Access Journals (Sweden)

    Satoshi Suzuki

    2013-03-01

    Full Text Available Several topics in projects for mechatronics studies, which are 'Human Adaptive Mechatronics (HAM' and 'Human-System Modelling (HSM', are presented in this paper. The main research theme of the HAM project is a design strategy for a new intelligent mechatronics system, which enhances operators' skills during machine operation. Skill analyses and control system design have been addressed. In the HSM project, human modelling based on hierarchical classification of skills was studied, including the following five types of skills: social, planning, cognitive, motion and sensory-motor skills. This paper includes digests of these research topics and the outcomes concerning each type of skill. Relationships with other research activities, knowledge and information that will be helpful for readers who are trying to study assistive human-mechatronics systems are also mentioned.

  3. Animal Models of Human Placentation - A Review

    DEFF Research Database (Denmark)

    Carter, Anthony Michael

    2007-01-01

    This review examines the strengths and weaknesses of animal models of human placentation and pays particular attention to the mouse and non-human primates. Analogies can be drawn between mouse and human in placental cell types and genes controlling placental development. There are, however...... and delivers poorly developed young. Guinea pig is a good alternative rodent model and among the few species known to develop pregnancy toxaemia. The sheep is well established as a model in fetal physiology but is of limited value for placental research. The ovine placenta is epitheliochorial...

  4. Avaliação da isquemia cerebral pela respiração mitocondrial: modelo experimental Study of brain ischemia by mitochondrial respiration: experimental model

    Directory of Open Access Journals (Sweden)

    Carlos Gilberto Carlotti Junior

    2001-06-01

    Full Text Available A isquemia cerebral acontece em várias doenças. Um dos fatores críticos para a recuperação de um paciente é a duração do processo isquêmico. A atividade cerebral depende do suprimento de energia, isto sugere que o estudo da função mitocondrial pode ser utilizado para a avaliação do dano neuronal. O objetivo deste trabalho foi o de estudar a respiração mitocondrial pela oclusão da artéria cerebral média esquerda pela técnica do fio intraluminal. Ratos da raça Wistar foram subdivididos em 4 grupos: controle e 15, 30 e 60 minutos de oclusão. Os resultados mostraram que não há diferença estatisticamente significativa entre o grupo de 15 minutos e o grupo controle. O grupo de 30 minutos teve diminuição do estado III da respiração mitocondrial comparado com o grupo controle. O grupo de 60 minutos teve diminuição dos estados III e IV comparados com o grupo controle. A respiração mitocondrial permitiu uma avaliação efetiva e precoce do processo isquêmico focal no cérebro do rato.Brain ischemia occurs in several diseases. One of the critical factors for recovery of patients is the duration of the ischemic process. Brain activity depends on the energetic supply, it suggests that the study of mitochondrial function can be useful for evaluation of neuronal damage. The purpose of the present research was to study the mitochondrial respiration by occlusion of the left middle cerebral artery by intraluminal suture technique. Adults Wistar rats were subdivided in 4 groups: control, 15, 30 and 60 minutes of occlusion. Results showed that there was no significant difference between the group of 15 minutes and the control group. The group of 30 minutes had significant decrease of state III of mitochondrial respiration compared with control group. The group of 60 minutes had significant decrease in state III and IV of mitochondrial respiration compared with control group. Mitochondrial respiration allowed an early and effective

  5. The Human-Artifact Model

    DEFF Research Database (Denmark)

    Bødker, Susanne; Klokmose, Clemens Nylandsted

    2011-01-01

    needs to support such development through concepts and methods. This leads to a methodological approach that focuses on new artifacts to supplement and substitute existing artifacts. Through a design case, we develop the methodological approach and illustrate how the human–artifact model can be applied...... to analyze present artifacts and to design future ones. The model is used to structure such analysis and to reason about findings while providing leverage from activity theoretical insights on mediation, dialectics, and levels of activity....

  6. Patterns of root respiration rates and morphological traits in 13 tree species in a tropical forest.

    Science.gov (United States)

    Makita, Naoki; Kosugi, Yoshiko; Dannoura, Masako; Takanashi, Satoru; Niiyama, Kaoru; Kassim, Abd Rahman; Nik, Abdul Rahim

    2012-03-01

    The root systems of forest trees are composed of different diameters and heterogeneous physiological traits. However, the pattern of root respiration rates from finer and coarser roots across various tropical species remains unknown. To clarify how respiration is related to the morphological traits of roots, we evaluated specific root respiration and its relationships to mean root diameter (D) of various diameter and root tissue density (RTD; root mass per unit root volume; gcm(-3)) and specific root length (SRL; root length per unit root mass; mg(-1)) of the fine roots among and within 14 trees of 13 species from a primary tropical rainforest in the Pasoh Forest Reserve in Peninsular Malaysia. Coarse root (2-269mm) respiration rates increased with decreasing D, resulting in significant relationships between root respiration and diameter across species. A model based on a radial gradient of respiration rates of coarse roots simulated the exponential decrease in respiration with diameter. The respiration rate of fine roots (diameter roots. For fine roots, the mean respiration rates for each species increased with decreasing D. The respiration rates of fine roots declined markedly with increasing RTD and increased with increasing SRL, which explained a significant portion of the variation in the respiration among the 14 trees from 13 species examined. Our results indicate that coarse root respiration in tree species follows a basic relationship with D across species and that most of the variation in fine root respiration among species is explained by D, RTD and SRL. We found that the relationship between root respiration and morphological traits provides a quantitative basis for separating fine roots from coarse roots and that the pattern holds across different species.

  7. Particle loading time and humidity effects on the efficiency of an N95 filtering facepiece respirator model under constant and inhalation cyclic flows.

    Science.gov (United States)

    Mahdavi, Alireza; Haghighat, Fariborz; Bahloul, Ali; Brochot, Clothilde; Ostiguy, Claude

    2015-06-01

    It is necessary to investigate the efficiencies of filtering facepiece respirators (FFRs) exposed to ultrafine particles (UFPs) for long periods of time, since the particle loading time may potentially affect the efficiency of FFRs. This article aims to investigate the filtration efficiency for a model of electrostatic N95 FFRs with constant and 'inhalation-only' cyclic flows, in terms of particle loading time effect, using different humidity conditions. Filters were exposed to generated polydisperse NaCl particles. Experiments were performed mimicking an 'inhalation-only' scenario with a cyclic flow of 85 l min(-1) as the minute volume [or 170 l min(-1) as mean inhalation flow (MIF)] and for two constant flows of 85 and 170 l min(-1), under three relative humidity (RH) levels of 10, 50, and 80%. Each test was performed for loading time periods of 6h and the particle penetration (10-205.4nm in electrical mobility diameter) was measured once every 2h. For a 10% RH, the penetration of smaller size particles (penetrating particle size (MPPS), decreased over time for both constant and cyclic flows. For 50 and 80% RH levels, the changes in penetration were typically observed in an opposite direction with less magnitude. The penetrations at MPPS increased with respect to loading time under constant flow conditions (85 and 170 l min(-1)): it did not substantially increase under cyclic flows. The comparison of the cyclic flow (85 l min(-1) as minute volume) and constant flow equal to the cyclic flow minute volume indicated that, for all conditions the penetration was significantly less for the constant flow than that of cyclic flow. The comparison between the cyclic (170 l min(-1) as MIF) and constant flow equal to cyclic flow MIF indicated that, for the initial stage of loading, the penetrations were almost equal, but they were different for the final stages of the loading time. For a 10% RH, the penetration of a wide range of sizes was observed to be higher with the

  8. Human BDCM Mulit-Route PBPK Model

    Data.gov (United States)

    U.S. Environmental Protection Agency — This data set contains the code for the BDCM human multi-route model written in the programming language acsl. The final published manuscript is provided since it...

  9. Modeling Human Cancers in Drosophila.

    Science.gov (United States)

    Sonoshita, M; Cagan, R L

    2017-01-01

    Cancer is a complex disease that affects multiple organs. Whole-body animal models provide important insights into oncology that can lead to clinical impact. Here, we review novel concepts that Drosophila studies have established for cancer biology, drug discovery, and patient therapy. Genetic studies using Drosophila have explored the roles of oncogenes and tumor-suppressor genes that when dysregulated promote cancer formation, making Drosophila a useful model to study multiple aspects of transformation. Not limited to mechanism analyses, Drosophila has recently been showing its value in facilitating drug development. Flies offer rapid, efficient platforms by which novel classes of drugs can be identified as candidate anticancer leads. Further, we discuss the use of Drosophila as a platform to develop therapies for individual patients by modeling the tumor's genetic complexity. Drosophila provides both a classical and a novel tool to identify new therapeutics, complementing other more traditional cancer tools. © 2017 Elsevier Inc. All rights reserved.

  10. Modeling human learning involved in car driving

    OpenAIRE

    Wewerinke, P.H.

    1994-01-01

    In this paper, car driving is considered at the level of human tracking and maneuvering in the context of other traffic. A model analysis revealed the most salient features determining driving performance and safety. Learning car driving is modelled based on a system theoretical approach and based on a neural network approach. The aim of this research is to assess the relative merit of both approaches to describe human learning behavior in car driving specifically and in operating dynamic sys...

  11. Breathing simulator of workers for respirator performance test.

    Science.gov (United States)

    Yuasa, Hisashi; Kumita, Mikio; Honda, Takeshi; Kimura, Kazushi; Nozaki, Kosuke; Emi, Hitoshi; Otani, Yoshio

    2015-01-01

    Breathing machines are widely used to evaluate respirator performance but they are capable of generating only limited air flow patterns, such as, sine, triangular and square waves. In order to evaluate the respirator performance in practical use, it is desirable to test the respirator using the actual breathing patterns of wearers. However, it has been a difficult task for a breathing machine to generate such complicated flow patterns, since the human respiratory volume changes depending on the human activities and workload. In this study, we have developed an electromechanical breathing simulator and a respiration sampling device to record and reproduce worker's respiration. It is capable of generating various flow patterns by inputting breathing pattern signals recorded by a computer, as well as the fixed air flow patterns. The device is equipped with a self-control program to compensate the difference in inhalation and exhalation volume and the measurement errors on the breathing flow rate. The system was successfully applied to record the breathing patterns of workers engaging in welding and reproduced the breathing patterns.

  12. Role of UCP3 in state 4 respiration during contractile activity-induced mitochondrial biogenesis.

    Science.gov (United States)

    Ljubicic, Vladimir; Adhihetty, Peter J; Hood, David A

    2004-09-01

    In an effort to better characterize uncoupling protein-3 (UCP3) function in skeletal muscle, we assessed basal UCP3 protein content in rat intermyofibrillar (IMF) and subsarcolemmal (SS) mitochondrial subfractions in conjunction with measurements of state 4 respiration. UCP3 content was 1.3-fold (P respiration was 2.6-fold greater (P respiration by approximately 40% (P respiration in IMF mitochondria only. We used chronic electrical stimulation (3 h/day for 7 days) to investigate the relationship between changes in UCP3 protein expression and alterations in state 4 respiration during contractile activity-induced mitochondrial biogenesis. UCP3 content was increased by 1.9- and 2.3-fold in IMF and SS mitochondria, respectively, which exceeded the concurrent 40% (P respiration by 1.4-fold (P respiration in IMF mitochondria, which was independent of the induced twofold difference in UCP3 content due to chronic contractile activity. Thus modifications in UCP3 function are more important than changes in UCP3 expression in modifying state 4 respiration. This effect is evident in IMF but not SS mitochondria. We conclude that UCP3 at physiological concentrations accounts for a significant portion of state 4 respiration in both IMF and SS mitochondria, with the contribution being greater in the IMF subfraction. In addition, the contradiction between human and rat training studies with respect to UCP3 protein expression may partly be explained by the greater than twofold difference in mitochondrial UCP3 content between rat and human skeletal muscle.

  13. Computational Intelligence in a Human Brain Model

    Directory of Open Access Journals (Sweden)

    Viorel Gaftea

    2016-06-01

    Full Text Available This paper focuses on the current trends in brain research domain and the current stage of development of research for software and hardware solutions, communication capabilities between: human beings and machines, new technologies, nano-science and Internet of Things (IoT devices. The proposed model for Human Brain assumes main similitude between human intelligence and the chess game thinking process. Tactical & strategic reasoning and the need to follow the rules of the chess game, all are very similar with the activities of the human brain. The main objective for a living being and the chess game player are the same: securing a position, surviving and eliminating the adversaries. The brain resolves these goals, and more, the being movement, actions and speech are sustained by the vital five senses and equilibrium. The chess game strategy helps us understand the human brain better and easier replicate in the proposed ‘Software and Hardware’ SAH Model.

  14. Design of climate respiration chambers, adjustable to the metabolic mass of subjects

    NARCIS (Netherlands)

    Heetkamp, M.J.W.; Alferink, S.J.J.; Zandstra, T.; Hendriks, P.; Brand, van den H.; Gerrits, W.J.J.

    2015-01-01

    Open-circuit respiration chambers can be used to measure gas exchange and to calculate heat production (Q) of humans and animals. When studying short-term changes in Q, the size of the respiration chamber in relation to the subject of study is a point of concern. The washout time of a chamber,

  15. A humanized mouse model of tuberculosis.

    Directory of Open Access Journals (Sweden)

    Veronica E Calderon

    Full Text Available Mycobacterium tuberculosis (M.tb is the second leading infectious cause of death worldwide and the primary cause of death in people living with HIV/AIDS. There are several excellent animal models employed to study tuberculosis (TB, but many have limitations for reproducing human pathology and none are amenable to the direct study of HIV/M.tb co-infection. The humanized mouse has been increasingly employed to explore HIV infection and other pathogens where animal models are limiting. Our goal was to develop a small animal model of M.tb infection using the bone marrow, liver, thymus (BLT humanized mouse. NOD-SCID/γc(null mice were engrafted with human fetal liver and thymus tissue, and supplemented with CD34(+ fetal liver cells. Excellent reconstitution, as measured by expression of the human CD45 pan leukocyte marker by peripheral blood populations, was observed at 12 weeks after engraftment. Human T cells (CD3, CD4, CD8, as well as natural killer cells and monocyte/macrophages were all observed within the human leukocyte (CD45(+ population. Importantly, human T cells were functionally competent as determined by proliferative capacity and effector molecule (e.g. IFN-γ, granulysin, perforin expression in response to positive stimuli. Animals infected intranasally with M.tb had progressive bacterial infection in the lung and dissemination to spleen and liver from 2-8 weeks post infection. Sites of infection in the lung were characterized by the formation of organized granulomatous lesions, caseous necrosis, bronchial obstruction, and crystallization of cholesterol deposits. Human T cells were distributed throughout the lung, liver, and spleen at sites of inflammation and bacterial growth and were organized to the periphery of granulomas. These preliminary results demonstrate the potential to use the humanized mouse as a model of experimental TB.

  16. A statistical model of future human actions

    International Nuclear Information System (INIS)

    Woo, G.

    1992-02-01

    A critical review has been carried out of models of future human actions during the long term post-closure period of a radioactive waste repository. Various Markov models have been considered as alternatives to the standard Poisson model, and the problems of parameterisation have been addressed. Where the simplistic Poisson model unduly exaggerates the intrusion risk, some form of Markov model may have to be introduced. This situation may well arise for shallow repositories, but it is less likely for deep repositories. Recommendations are made for a practical implementation of a computer based model and its associated database. (Author)

  17. The significance of respiration timing in the energetics estimates of free-ranging killer whales (Orcinus orca).

    Science.gov (United States)

    Roos, Marjoleine M H; Wu, Gi-Mick; Miller, Patrick J O

    2016-07-01

    Respiration rate has been used as an indicator of metabolic rate and associated cost of transport (COT) of free-ranging cetaceans, discounting potential respiration-by-respiration variation in O2 uptake. To investigate the influence of respiration timing on O2 uptake, we developed a dynamic model of O2 exchange and storage. Individual respiration events were revealed from kinematic data from 10 adult Norwegian herring-feeding killer whales (Orcinus orca) recorded with high-resolution tags (DTAGs). We compared fixed O2 uptake per respiration models with O2 uptake per respiration estimated through a simple 'broken-stick' O2-uptake function, in which O2 uptake was assumed to be the maximum possible O2 uptake when stores are depleted or maximum total body O2 store minus existing O2 store when stores are close to saturated. In contrast to findings assuming fixed O2 uptake per respiration, uptake from the broken-stick model yielded a high correlation (r(2)>0.9) between O2 uptake and activity level. Moreover, we found that respiration intervals increased and became less variable at higher swimming speeds, possibly to increase O2 uptake efficiency per respiration. As found in previous studies, COT decreased monotonically versus speed using the fixed O2 uptake per respiration models. However, the broken-stick uptake model yielded a curvilinear COT curve with a clear minimum at typical swimming speeds of 1.7-2.4 m s(-1) Our results showed that respiration-by-respiration variation in O2 uptake is expected to be significant. And though O2 consumption measurements of COT for free-ranging cetaceans remain impractical, accounting for the influence of respiration timing on O2 uptake will lead to more consistent predictions of field metabolic rates than using respiration rate alone. © 2016. Published by The Company of Biologists Ltd.

  18. Material Models for the Human Torso Finite Element Model

    Science.gov (United States)

    2018-04-04

    ARL-TR-8338 ● Apr 2018 US Army Research Laboratory Material Models for the Human Torso Finite Element Model by Carolyn E...longer needed. Do not return it to the originator. ARL-TR-8338 ● Apr 2018 US Army Research Laboratory Material Models for the...Weapons and Materials Research Directorate, ARL Approved for public release; distribution is unlimited. ii REPORT

  19. Modeling human learning involved in car driving

    NARCIS (Netherlands)

    Wewerinke, P.H.

    1994-01-01

    In this paper, car driving is considered at the level of human tracking and maneuvering in the context of other traffic. A model analysis revealed the most salient features determining driving performance and safety. Learning car driving is modelled based on a system theoretical approach and based

  20. A Model of the Human Eye

    Science.gov (United States)

    Colicchia, G.; Wiesner, H.; Waltner, C.; Zollman, D.

    2008-01-01

    We describe a model of the human eye that incorporates a variable converging lens. The model can be easily constructed by students with low-cost materials. It shows in a comprehensible way the functionality of the eye's optical system. Images of near and far objects can be focused. Also, the defects of near and farsighted eyes can be demonstrated.

  1. Mathematical human body modelling for impact loading

    NARCIS (Netherlands)

    Happee, R.; Morsink, P.L.J.; Wismans, J.S.H.M.

    1999-01-01

    Mathematical modelling of the human body is widely used for automotive crash safety research and design. Simulations have contributed to a reduction of injury numbers by optimisation of vehicle structures and restraint systems. Currently such simulations are largely performed using occupant models

  2. Mathematical models of human african trypanosomiasis epidemiology.

    Science.gov (United States)

    Rock, Kat S; Stone, Chris M; Hastings, Ian M; Keeling, Matt J; Torr, Steve J; Chitnis, Nakul

    2015-03-01

    Human African trypanosomiasis (HAT), commonly called sleeping sickness, is caused by Trypanosoma spp. and transmitted by tsetse flies (Glossina spp.). HAT is usually fatal if untreated and transmission occurs in foci across sub-Saharan Africa. Mathematical modelling of HAT began in the 1980s with extensions of the Ross-Macdonald malaria model and has since consisted, with a few exceptions, of similar deterministic compartmental models. These models have captured the main features of HAT epidemiology and provided insight on the effectiveness of the two main control interventions (treatment of humans and tsetse fly control) in eliminating transmission. However, most existing models have overestimated prevalence of infection and ignored transient dynamics. There is a need for properly validated models, evolving with improved data collection, that can provide quantitative predictions to help guide control and elimination strategies for HAT. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Human models of acute lung injury

    Directory of Open Access Journals (Sweden)

    Alastair G. Proudfoot

    2011-03-01

    Full Text Available Acute lung injury (ALI is a syndrome that is characterised by acute inflammation and tissue injury that affects normal gas exchange in the lungs. Hallmarks of ALI include dysfunction of the alveolar-capillary membrane resulting in increased vascular permeability, an influx of inflammatory cells into the lung and a local pro-coagulant state. Patients with ALI present with severe hypoxaemia and radiological evidence of bilateral pulmonary oedema. The syndrome has a mortality rate of approximately 35% and usually requires invasive mechanical ventilation. ALI can follow direct pulmonary insults, such as pneumonia, or occur indirectly as a result of blood-borne insults, commonly severe bacterial sepsis. Although animal models of ALI have been developed, none of them fully recapitulate the human disease. The differences between the human syndrome and the phenotype observed in animal models might, in part, explain why interventions that are successful in models have failed to translate into novel therapies. Improved animal models and the development of human in vivo and ex vivo models are therefore required. In this article, we consider the clinical features of ALI, discuss the limitations of current animal models and highlight how emerging human models of ALI might help to answer outstanding questions about this syndrome.

  4. General Instructions for Disposable Respirators

    Centers for Disease Control (CDC) Podcasts

    2009-04-09

    This podcast, intended for the general public, demonstrates how to put on and take off disposable respirators that are to be used in areas affected by the influenza outbreak.  Created: 4/9/2009 by CDC, National Institute for Occupational Safety and Health (NIOSH).   Date Released: 4/29/2009.

  5. Use of Facemasks and Respirators

    Centers for Disease Control (CDC) Podcasts

    2007-05-15

    This program demonstrates the differences of facemasks and respirators that are to be used in public settings during an influenza pandemic.  Created: 5/15/2007 by CDC, National Institute for Occupational Safety and Health (NIOSH).   Date Released: 5/25/2007.

  6. Contribution of root respiration to soil respiration in a C3/C4 mixed ...

    Indian Academy of Sciences (India)

    Unknown

    Root respiration can be estimated by the differences between soil respiration and microbial respiration. 2.5 Statistical analysis. Coefficient of variation (CV) was calculated to provide a measure of within-site variation of soil respiration, soil temperature, soil moisture content, root biomass, micro- bial biomass carbon, and total ...

  7. Evaluation of the approach to respirable quartz exposure control in U.S. coal mines.

    Science.gov (United States)

    Joy, Gerald J

    2012-01-01

    Occupational exposure to high levels of respirable quartz can result in respiratory and other diseases in humans. The Mine Safety and Health Adminstration (MSHA) regulates exposure to respirable quartz in coal mines indirectly through reductions in the respirable coal mine dust exposure limit based on the content of quartz in the airborne respirable dust. This reduction is implemented when the quartz content of airborne respirable dust exceeds 5% by weight. The intent of this dust standard reduction is to restrict miners' exposure to respirable quartz to a time-weighted average concentration of 100 μg/m(3). The effectiveness of this indirect approach to control quartz exposure was evaluated by analyzing respirable dust samples collected by MSHA inspectors from 1995 through 2008. The performance of the current regulatory approach was found to be lacking due to the use of a variable property-quartz content in airborne dust-to establish a standard for subsequent exposures. In one situation, 11.7% (4370/37,346) of samples that were below the applicable respirable coal mine dust exposure limit exceeded 100 μg/m(3) quartz. In a second situation, 4.4% (895/20,560) of samples with 5% or less quartz content in the airborne respirable dust exceeded 100 μg/m(3) quartz. In these two situations, the samples exceeding 100 μg/m(3) quartz were not subject to any potential compliance action. Therefore, the current respirable quartz exposure control approach does not reliably maintain miner exposure below 100 μg/m(3) quartz. A separate and specific respirable quartz exposure standard may improve control of coal miners' occupational exposure to respirable quartz.

  8. Identification of walking human model using agent-based modelling

    Science.gov (United States)

    Shahabpoor, Erfan; Pavic, Aleksandar; Racic, Vitomir

    2018-03-01

    The interaction of walking people with large vibrating structures, such as footbridges and floors, in the vertical direction is an important yet challenging phenomenon to describe mathematically. Several different models have been proposed in the literature to simulate interaction of stationary people with vibrating structures. However, the research on moving (walking) human models, explicitly identified for vibration serviceability assessment of civil structures, is still sparse. In this study, the results of a comprehensive set of FRF-based modal tests were used, in which, over a hundred test subjects walked in different group sizes and walking patterns on a test structure. An agent-based model was used to simulate discrete traffic-structure interactions. The occupied structure modal parameters found in tests were used to identify the parameters of the walking individual's single-degree-of-freedom (SDOF) mass-spring-damper model using 'reverse engineering' methodology. The analysis of the results suggested that the normal distribution with the average of μ = 2.85Hz and standard deviation of σ = 0.34Hz can describe human SDOF model natural frequency. Similarly, the normal distribution with μ = 0.295 and σ = 0.047 can describe the human model damping ratio. Compared to the previous studies, the agent-based modelling methodology proposed in this paper offers significant flexibility in simulating multi-pedestrian walking traffics, external forces and simulating different mechanisms of human-structure and human-environment interaction at the same time.

  9. Mitochondrial Respiration Is Reduced in Atherosclerosis, Promoting Necrotic Core Formation and Reducing Relative Fibrous Cap Thickness.

    Science.gov (United States)

    Yu, Emma P K; Reinhold, Johannes; Yu, Haixiang; Starks, Lakshi; Uryga, Anna K; Foote, Kirsty; Finigan, Alison; Figg, Nichola; Pung, Yuh-Fen; Logan, Angela; Murphy, Michael P; Bennett, Martin

    2017-12-01

    Mitochondrial DNA (mtDNA) damage is present in murine and human atherosclerotic plaques. However, whether endogenous levels of mtDNA damage are sufficient to cause mitochondrial dysfunction and whether decreasing mtDNA damage and improving mitochondrial respiration affects plaque burden or composition are unclear. We examined mitochondrial respiration in human atherosclerotic plaques and whether augmenting mitochondrial respiration affects atherogenesis. Human atherosclerotic plaques showed marked mitochondrial dysfunction, manifested as reduced mtDNA copy number and oxygen consumption rate in fibrous cap and core regions. Vascular smooth muscle cells derived from plaques showed impaired mitochondrial respiration, reduced complex I expression, and increased mitophagy, which was induced by oxidized low-density lipoprotein. Apolipoprotein E-deficient (ApoE -/- ) mice showed decreased mtDNA integrity and mitochondrial respiration, associated with increased mitochondrial reactive oxygen species. To determine whether alleviating mtDNA damage and increasing mitochondrial respiration affects atherogenesis, we studied ApoE -/- mice overexpressing the mitochondrial helicase Twinkle (Tw + /ApoE -/- ). Tw + /ApoE -/- mice showed increased mtDNA integrity, copy number, respiratory complex abundance, and respiration. Tw + /ApoE -/- mice had decreased necrotic core and increased fibrous cap areas, and Tw + /ApoE -/- bone marrow transplantation also reduced core areas. Twinkle increased vascular smooth muscle cell mtDNA integrity and respiration. Twinkle also promoted vascular smooth muscle cell proliferation and protected both vascular smooth muscle cells and macrophages from oxidative stress-induced apoptosis. Endogenous mtDNA damage in mouse and human atherosclerosis is associated with significantly reduced mitochondrial respiration. Reducing mtDNA damage and increasing mitochondrial respiration decrease necrotic core and increase fibrous cap areas independently of changes in

  10. Bariatric surgery rapidly improves mitochondrial respiration in morbidly obese patients.

    Science.gov (United States)

    Nijhawan, Sheetal; Richards, William; O'Hea, Martha F; Audia, Jonathon P; Alvarez, Diego F

    2013-12-01

    Obesity and its attendant comorbidities are an emerging epidemic. Chronic metabolic inflammation (metainflammation) is thought to precipitate obesity-associated morbidities; however, its mechanistic progression is poorly understood. Moreover, although interventions such as diet, exercise, and bariatric surgery can control body weight, their effects on metainflammation are also poorly understood. Recently, metainflammation and the pathobiology of obesity have been linked to mitochondrial dysfunction. Herein we examined the effects of bariatric surgery on mitochondrial respiration as an index of resolving metainflammation in morbidly obese patients. This institutional review board-approved study involved morbidly obese patients (body mass index > 35 kg/m(2)) undergoing sleeve gastrectomy or Roux-en-Y gastric bypass. Mitochondrial respiration was assessed in peripheral blood monocytes and in skeletal muscle samples before surgery and at 12 weeks after surgery. Patient biometrics, homeostasis model assessment-estimated insulin resistance (HOMA-IR) score, C-reactive protein, and lipid profile were analyzed. Twenty patients were enrolled and showed an average percent excess body weight loss of 30.3% weight loss at 12 weeks after surgery. Average HOMA-IR score decreased from 3.0 to 1.2 in insulin-resistant patients. C-reactive protein, an index of metainflammation, showed a modest decrease. Lipid profile remained stable. Intriguingly, mitochondrial basal and maximal respiration rates in peripheral blood monocytes increased after surgery. Basal rates of skeletal muscle mitochondrial respiration were unchanged, but the maximal respiration rate trended toward an increase after surgery. Cellular and tissue mitochondrial respiration increased in a morbidly obese patient cohort after laparoscopic bariatric surgery. These changes were consistent in patients with postsurgical weight loss. Importantly, no significant changes or improvements occurred in canonical indices used to

  11. Seasonality of temperate forest photosynthesis and daytime respiration

    Science.gov (United States)

    Wehr, R.; Munger, J. W.; McManus, J. B.; Nelson, D. D.; Zahniser, M. S.; Davidson, E. A.; Wofsy, S. C.; Saleska, S. R.

    2016-06-01

    Terrestrial ecosystems currently offset one-quarter of anthropogenic carbon dioxide (CO2) emissions because of a slight imbalance between global terrestrial photosynthesis and respiration. Understanding what controls these two biological fluxes is therefore crucial to predicting climate change. Yet there is no way of directly measuring the photosynthesis or daytime respiration of a whole ecosystem of interacting organisms; instead, these fluxes are generally inferred from measurements of net ecosystem-atmosphere CO2 exchange (NEE), in a way that is based on assumed ecosystem-scale responses to the environment. The consequent view of temperate deciduous forests (an important CO2 sink) is that, first, ecosystem respiration is greater during the day than at night; and second, ecosystem photosynthetic light-use efficiency peaks after leaf expansion in spring and then declines, presumably because of leaf ageing or water stress. This view has underlain the development of terrestrial biosphere models used in climate prediction and of remote sensing indices of global biosphere productivity. Here, we use new isotopic instrumentation to determine ecosystem photosynthesis and daytime respiration in a temperate deciduous forest over a three-year period. We find that ecosystem respiration is lower during the day than at night—the first robust evidence of the inhibition of leaf respiration by light at the ecosystem scale. Because they do not capture this effect, standard approaches overestimate ecosystem photosynthesis and daytime respiration in the first half of the growing season at our site, and inaccurately portray ecosystem photosynthetic light-use efficiency. These findings revise our understanding of forest-atmosphere carbon exchange, and provide a basis for investigating how leaf-level physiological dynamics manifest at the canopy scale in other ecosystems.

  12. Automatic respiration tracking for radiotherapy using optical 3D camera

    Science.gov (United States)

    Li, Tuotuo; Geng, Jason; Li, Shidong

    2013-03-01

    images can be accurately represented as weighted summation of those eigen-vectors, which can be easily discriminated with a trained classifier. We developed algorithms, software and integrated with an O3D imaging system to perform the respiration tracking automatically. The resulting respiration tracking system requires no human intervene during it tracking operation. Experimental results show that our approach to respiration tracking is more accurate and robust than the methods using manual selected markers, even in the presence of incomplete imaging data.

  13. Analisis Model Pengukuran Human Capital dalam Organisasi

    Directory of Open Access Journals (Sweden)

    Cecep Hidayat

    2013-11-01

    Full Text Available Measurement of human capital is not an easy to do because it is dynamic and always changing in accordance with the changing circumstances. Determination of dimensions and indicators of measurement needs to consider various factors such as situations and also the research scopes. This article has objectives to review the concepts, dimensions and measurement models of human capital. The research method used was literature study with a major reference source from current journal articles that discuss the measurement of human capital. Results of the study showed that basically the definition set forth in any dimension containing either explicitly or implicitly. In addition, the result indicated that there are three main categories of equality among researchers regarding the definition of human capital which emphasizes on: economic value/productivity, education, and abilities/competencies. The results also showed that the use of definitions, dimensions, and indicators for measurement of human capital depends on the situation, the scope of research, and the size of the organization. The conclusion of the study indicated that the measurement model and determination of dimensions and indicators of human capital measurement will determine the effectiveness of the measurement, and will have an impact on organizational performance.

  14. SU-E-J-67: Evaluation of Breathing Patterns for Respiratory-Gated Radiation Therapy Using Respiration Regularity Index

    International Nuclear Information System (INIS)

    Cheong, K; Lee, M; Kang, S; Yoon, J; Park, S; Hwang, T; Kim, H; Kim, K; Han, T; Bae, H

    2014-01-01

    Purpose: Despite the importance of accurately estimating the respiration regularity of a patient in motion compensation treatment, an effective and simply applicable method has rarely been reported. The authors propose a simple respiration regularity index based on parameters derived from a correspondingly simplified respiration model. Methods: In order to simplify a patient's breathing pattern while preserving the data's intrinsic properties, we defined a respiration model as a power of cosine form with a baseline drift. According to this respiration formula, breathing-pattern fluctuation could be explained using four factors: sample standard deviation of respiration period, sample standard deviation of amplitude and the results of simple regression of the baseline drift (slope and standard deviation of residuals of a respiration signal. Overall irregularity (δ) was defined as a Euclidean norm of newly derived variable using principal component analysis (PCA) for the four fluctuation parameters. Finally, the proposed respiration regularity index was defined as ρ=ln(1+(1/ δ))/2, a higher ρ indicating a more regular breathing pattern. Subsequently, we applied it to simulated and clinical respiration signals from real-time position management (RPM; Varian Medical Systems, Palo Alto, CA) and investigated respiration regularity. Moreover, correlations between the regularity of the first session and the remaining fractions were investigated using Pearson's correlation coefficient. Results: The respiration regularity was determined based on ρ; patients with ρ 0.7 was suitable for respiratory-gated radiation therapy (RGRT). Fluctuations in breathing cycle and amplitude were especially determinative of ρ. If the respiration regularity of a patient's first session was known, it could be estimated through subsequent sessions. Conclusions: Respiration regularity could be objectively determined using a respiration regularity index, ρ. Such single-index testing of

  15. Models of the Human in Tantric Hinduism

    DEFF Research Database (Denmark)

    Olesen, Bjarne Wernicke; Flood, Gavin

    2019-01-01

    This research project explores the origins, developments and transformations of yogic models of the human (e.g. kuṇḍalinī yoga, the cakra system and ritual sex) in the tantric goddess traditions or what might be called Śāktism of medieval India. These Śākta models of esoteric anatomy originating...... in medieval ascetic traditions became highly influential in South Asia and were popularized in the West....

  16. Are animal models predictive for humans?

    Directory of Open Access Journals (Sweden)

    Greek Ray

    2009-01-01

    Full Text Available Abstract It is one of the central aims of the philosophy of science to elucidate the meanings of scientific terms and also to think critically about their application. The focus of this essay is the scientific term predict and whether there is credible evidence that animal models, especially in toxicology and pathophysiology, can be used to predict human outcomes. Whether animals can be used to predict human response to drugs and other chemicals is apparently a contentious issue. However, when one empirically analyzes animal models using scientific tools they fall far short of being able to predict human responses. This is not surprising considering what we have learned from fields such evolutionary and developmental biology, gene regulation and expression, epigenetics, complexity theory, and comparative genomics.

  17. [Primate models of human viral hepatitis].

    Science.gov (United States)

    Poleshchuk, V F; Mikhaĭlov, M I; Zamiatina, N A

    2006-01-01

    The paper summarizes the updates available in the literature and the authors' own data on the etiology of hepatitis, its models, and experimental studies on susceptible simian types. A comparative analysis of the etiological agents--the causative agents of simian and human hepatitis will give a better insight into the evolution of its viruses.

  18. Human driven transitions in complex model ecosystems

    Science.gov (United States)

    Harfoot, Mike; Newbold, Tim; Tittinsor, Derek; Purves, Drew

    2015-04-01

    Human activities have been observed to be impacting ecosystems across the globe, leading to reduced ecosystem functioning, altered trophic and biomass structure and ultimately ecosystem collapse. Previous attempts to understand global human impacts on ecosystems have usually relied on statistical models, which do not explicitly model the processes underlying the functioning of ecosystems, represent only a small proportion of organisms and do not adequately capture complex non-linear and dynamic responses of ecosystems to perturbations. We use a mechanistic ecosystem model (1), which simulates the underlying processes structuring ecosystems and can thus capture complex and dynamic interactions, to investigate boundaries of complex ecosystems to human perturbation. We explore several drivers including human appropriation of net primary production and harvesting of animal biomass. We also present an analysis of the key interactions between biotic, societal and abiotic earth system components, considering why and how we might think about these couplings. References: M. B. J. Harfoot et al., Emergent global patterns of ecosystem structure and function from a mechanistic general ecosystem model., PLoS Biol. 12, e1001841 (2014).

  19. Quality assessment of human behavior models

    NARCIS (Netherlands)

    Doesburg, W.A. van

    2007-01-01

    Accurate and efficient models of human behavior offer great potential in military and crisis management applications. However, little attention has been given to the man ner in which it can be determined if this potential is actually realized. In this study a quality assessment approach that

  20. Future of human models for crash analysis

    NARCIS (Netherlands)

    Wismans, J.S.H.M.; Happee, R.; Hoof, J.F.A.M. van; Lange, R. de

    2001-01-01

    In the crash safety field mathematical models can be applied in practically all area's of research and development including: reconstruction of actual accidents, design (CAD) of the crash response of vehicles, safety devices and roadside facilities and in support of human impact biomechanical

  1. Optical models of the human eye.

    Science.gov (United States)

    Atchison, David A; Thibos, Larry N

    2016-03-01

    Optical models of the human eye have been used in visual science for purposes such as providing a framework for explaining optical phenomena in vision, for predicting how refraction and aberrations are affected by change in ocular biometry and as computational tools for exploring the limitations imposed on vision by the optical system of the eye. We address the issue of what is understood by optical model eyes, discussing the 'encyclopaedia' and 'toy train' approaches to modelling. An extensive list of purposes of models is provided. We discuss many of the theoretical types of optical models (also schematic eyes) of varying anatomical accuracy, including single, three and four refracting surface variants. We cover the models with lens structure in the form of nested shells and gradient index. Many optical eye models give accurate predictions only for small angles and small fields of view. If aberrations and image quality are important to consider, such 'paraxial' model eyes must be replaced by 'finite model' eyes incorporating features such as aspheric surfaces, tilts and decentrations, wavelength-dependent media and curved retinas. Many optical model eyes are population averages and must become adaptable to account for age, gender, ethnicity, refractive error and accommodation. They can also be customised for the individual when extensive ocular biometry and optical performance data are available. We consider which optical model should be used for a particular purpose, adhering to the principle that the best model is the simplest fit for the task. We provide a glimpse into the future of optical models of the human eye. This review is interwoven with historical developments, highlighting the important people who have contributed so richly to our understanding of visual optics. © 2016 The Authors. Clinical and Experimental Optometry © 2016 Optometry Australia.

  2. Soil respiration across a permafrost transition zone: spatial structure and environmental correlates

    Science.gov (United States)

    Stegen, James C.; Anderson, Carolyn G.; Bond-Lamberty, Ben; Crump, Alex R.; Chen, Xingyuan; Hess, Nancy

    2017-09-01

    Soil respiration is a key ecosystem function whereby shifts in respiration rates can shift systems from carbon sinks to sources. Soil respiration in permafrost-associated systems is particularly important given climate change driven permafrost thaw that leads to significant uncertainty in resulting ecosystem carbon dynamics. Here we characterize the spatial structure and environmental drivers of soil respiration across a permafrost transition zone. We find that soil respiration is characterized by a non-linear threshold that occurs at active-layer depths greater than 140 cm. We also find that within each season, tree basal area is a dominant driver of soil respiration regardless of spatial scale, but only in spatial domains with significant spatial variability in basal area. Our analyses further show that spatial variation (the coefficient of variation) and mean-variance power-law scaling of soil respiration in our boreal system are consistent with previous work in other ecosystems (e.g., tropical forests) and in population ecology, respectively. Comparing our results to those in other ecosystems suggests that temporally stable features such as tree-stand structure are often primary drivers of spatial variation in soil respiration. If so, this provides an opportunity to better estimate the magnitude and spatial variation in soil respiration through remote sensing. Combining such an approach with broader knowledge of thresholding behavior - here related to active layer depth - would provide empirical constraints on models aimed at predicting ecosystem responses to ongoing permafrost thaw.

  3. Evaluation of Five Decontamination Methods for Filtering Facepiece Respirators

    Science.gov (United States)

    Bergman, Michael S.; Eimer, Benjamin C.; Shaffer, Ronald E.

    2009-01-01

    Concerns have been raised regarding the availability of National Institute for Occupational Safety and Health (NIOSH)-certified N95 filtering facepiece respirators (FFRs) during an influenza pandemic. One possible strategy to mitigate a respirator shortage is to reuse FFRs following a biological decontamination process to render infectious material on the FFR inactive. However, little data exist on the effects of decontamination methods on respirator integrity and performance. This study evaluated five decontamination methods [ultraviolet germicidal irradiation (UVGI), ethylene oxide, vaporized hydrogen peroxide (VHP), microwave oven irradiation, and bleach] using nine models of NIOSH-certified respirators (three models each of N95 FFRs, surgical N95 respirators, and P100 FFRs) to determine which methods should be considered for future research studies. Following treatment by each decontamination method, the FFRs were evaluated for changes in physical appearance, odor, and laboratory performance (filter aerosol penetration and filter airflow resistance). Additional experiments (dry heat laboratory oven exposures, off-gassing, and FFR hydrophobicity) were subsequently conducted to better understand material properties and possible health risks to the respirator user following decontamination. However, this study did not assess the efficiency of the decontamination methods to inactivate viable microorganisms. Microwave oven irradiation melted samples from two FFR models. The remainder of the FFR samples that had been decontaminated had expected levels of filter aerosol penetration and filter airflow resistance. The scent of bleach remained noticeable following overnight drying and low levels of chlorine gas were found to off-gas from bleach-decontaminated FFRs when rehydrated with deionized water. UVGI, ethylene oxide (EtO), and VHP were found to be the most promising decontamination methods; however, concerns remain about the throughput capabilities for EtO and VHP

  4. Effects of assimilate supply on root and microbial components of soil respiration in a mountain grassland.

    Science.gov (United States)

    Schmitt, M.; Siegwolf, R.; Ekblad, A.; Pfahringer, N.; Bahn, M.

    2012-04-01

    in our experiment was markedly higher in the control than in the substrate limited treatments. It was likely related to an increase in microbial biomass turnover and not to SOM degradation, which suggests an apparent priming effect. Our results indicate that substrate limitation through lower or no photosynthesis generated by clipping and shading lead to a reduction of soil respiration, which was reversed by application of a labile C source. We conclude that short-term variations in fresh organic carbon availability may have more pronounced effects on microbial, than on root respiration. This needs to be accounted for when modelling soil C fluxes in highly dynamic environments.

  5. Modeling Operations Costs for Human Exploration Architectures

    Science.gov (United States)

    Shishko, Robert

    2013-01-01

    Operations and support (O&S) costs for human spaceflight have not received the same attention in the cost estimating community as have development costs. This is unfortunate as O&S costs typically comprise a majority of life-cycle costs (LCC) in such programs as the International Space Station (ISS) and the now-cancelled Constellation Program. Recognizing this, the Constellation Program and NASA HQs supported the development of an O&S cost model specifically for human spaceflight. This model, known as the Exploration Architectures Operations Cost Model (ExAOCM), provided the operations cost estimates for a variety of alternative human missions to the moon, Mars, and Near-Earth Objects (NEOs) in architectural studies. ExAOCM is philosophically based on the DoD Architecture Framework (DoDAF) concepts of operational nodes, systems, operational functions, and milestones. This paper presents some of the historical background surrounding the development of the model, and discusses the underlying structure, its unusual user interface, and lastly, previous examples of its use in the aforementioned architectural studies.

  6. Computer Modeling of Human Delta Opioid Receptor

    Directory of Open Access Journals (Sweden)

    Tatyana Dzimbova

    2013-04-01

    Full Text Available The development of selective agonists of δ-opioid receptor as well as the model of interaction of ligands with this receptor is the subjects of increased interest. In the absence of crystal structures of opioid receptors, 3D homology models with different templates have been reported in the literature. The problem is that these models are not available for widespread use. The aims of our study are: (1 to choose within recently published crystallographic structures templates for homology modeling of the human δ-opioid receptor (DOR; (2 to evaluate the models with different computational tools; and (3 to precise the most reliable model basing on correlation between docking data and in vitro bioassay results. The enkephalin analogues, as ligands used in this study, were previously synthesized by our group and their biological activity was evaluated. Several models of DOR were generated using different templates. All these models were evaluated by PROCHECK and MolProbity and relationship between docking data and in vitro results was determined. The best correlations received for the tested models of DOR were found between efficacy (erel of the compounds, calculated from in vitro experiments and Fitness scoring function from docking studies. New model of DOR was generated and evaluated by different approaches. This model has good GA341 value (0.99 from MODELLER, good values from PROCHECK (92.6% of most favored regions and MolProbity (99.5% of favored regions. Scoring function correlates (Pearson r = -0.7368, p-value = 0.0097 with erel of a series of enkephalin analogues, calculated from in vitro experiments. So, this investigation allows suggesting a reliable model of DOR. Newly generated model of DOR receptor could be used further for in silico experiments and it will give possibility for faster and more correct design of selective and effective ligands for δ-opioid receptor.

  7. Human physiologically based pharmacokinetic model for propofol

    Directory of Open Access Journals (Sweden)

    Schnider Thomas W

    2005-04-01

    Full Text Available Abstract Background Propofol is widely used for both short-term anesthesia and long-term sedation. It has unusual pharmacokinetics because of its high lipid solubility. The standard approach to describing the pharmacokinetics is by a multi-compartmental model. This paper presents the first detailed human physiologically based pharmacokinetic (PBPK model for propofol. Methods PKQuest, a freely distributed software routine http://www.pkquest.com, was used for all the calculations. The "standard human" PBPK parameters developed in previous applications is used. It is assumed that the blood and tissue binding is determined by simple partition into the tissue lipid, which is characterized by two previously determined set of parameters: 1 the value of the propofol oil/water partition coefficient; 2 the lipid fraction in the blood and tissues. The model was fit to the individual experimental data of Schnider et. al., Anesthesiology, 1998; 88:1170 in which an initial bolus dose was followed 60 minutes later by a one hour constant infusion. Results The PBPK model provides a good description of the experimental data over a large range of input dosage, subject age and fat fraction. Only one adjustable parameter (the liver clearance is required to describe the constant infusion phase for each individual subject. In order to fit the bolus injection phase, for 10 or the 24 subjects it was necessary to assume that a fraction of the bolus dose was sequestered and then slowly released from the lungs (characterized by two additional parameters. The average weighted residual error (WRE of the PBPK model fit to the both the bolus and infusion phases was 15%; similar to the WRE for just the constant infusion phase obtained by Schnider et. al. using a 6-parameter NONMEM compartmental model. Conclusion A PBPK model using standard human parameters and a simple description of tissue binding provides a good description of human propofol kinetics. The major advantage of a

  8. Economic analysis of implementing respirator program or ventilation system in a manufacturing environment

    International Nuclear Information System (INIS)

    Saidi-Mehrabab, M.

    2000-01-01

    The techniques and methods of developing cost models for respirators are discussed. Models are developed and implemented in this study for nineteen types of respirators in two major classes (air-purifying and supplied-air) and one L EV system. One respirator model is selected for detailed discussion from among the twenty models. The technical cost method is used in constructing the cost models for each of the respirators and the L EV system. In this methodology, the costs of purchasing and using a typical respirator or L EV system are divided into two categories, variable costs and fixed costs. Variable costs consists of the cost of replaceable components and probabilistic mortality cost. Fixed cost is the annualized capital requirement plus interest cost. The criteria for estimating some of the cost elements are based on existing equations in the literature, engineering judgement and manufacturer-provided information. A technical cost model results from the integration of this information into a computerized framework. The cost models for discussion are presented in the order of increasing computational complexity. Through the economic analysis, the lowest cost type in each class of respirator is determined. The determination criteria are based on the minimum total annual cost and highest benefit cost ratio. The selected lowest cost respirators are compared with the L EV system from the economic standpoint to reveal the cost optimal alternative

  9. Coupled Stochastic Time-Inverted Lagrangian Transport/Weather Forecast and Research/Vegetation Photosynthesis and Respiration Model. Part II; Simulations of Tower-Based and Airborne CO2 Measurements

    Science.gov (United States)

    Eluszkiewicz, Janusz; Nehrkorn, Thomas; Wofsy, Steven C.; Matross, Daniel; Gerbig, Christoph; Lin, John C.; Freitas, Saulo; Longo, Marcos; Andrews, Arlyn E.; Peters, Wouter

    2007-01-01

    This paper evaluates simulations of atmospheric CO2 measured in 2004 at continental surface and airborne receptors, intended to test the capability to use data with high temporal and spatial resolution for analyses of carbon sources and sinks at regional and continental scales. The simulations were performed using the Stochastic Time-Inverted Lagrangian Transport (STILT) model driven by the Weather Forecast and Research (WRF) model, and linked to surface fluxes from the satellite-driven Vegetation Photosynthesis and Respiration Model (VPRM). The simulations provide detailed representations of hourly CO2 tower data and reproduce the shapes of airborne vertical profiles with high fidelity. WRF meteorology gives superior model performance compared with standard meteorological products, and the impact of including WRF convective mass fluxes in the STILT trajectory calculations is significant in individual cases. Important biases in the simulation are associated with the nighttime CO2 build-up and subsequent morning transition to convective conditions, and with errors in the advected lateral boundary condition. Comparison of STILT simulations driven by the WRF model against those driven by the Brazilian variant of the Regional Atmospheric Modeling System (BRAMS) shows that model-to-model differences are smaller than between an individual transport model and observations, pointing to systematic errors in the simulated transport. Future developments in the WRF model s data assimilation capabilities, basic research into the fundamental aspects of trajectory calculations, and intercomparison studies involving other transport models, are possible venues for reducing these errors. Overall, the STILT/WRF/VPRM offers a powerful tool for continental and regional scale carbon flux estimates.

  10. Redefinition and global estimation of basal ecosystem respiration rate

    Science.gov (United States)

    Yuan, W.; Luo, Y.; Li, X.; Liu, S.; Yu, G.; Zhou, T.; Bahn, M.; Black, A.; Desai, A.R.; Cescatti, A.; Marcolla, B.; Jacobs, C.; Chen, J.; Aurela, M.; Bernhofer, C.; Gielen, B.; Bohrer, G.; Cook, D.R.; Dragoni, D.; Dunn, A.L.; Gianelle, D.; Grnwald, T.; Ibrom, A.; Leclerc, M.Y.; Lindroth, A.; Liu, H.; Marchesini, L.B.; Montagnani, L.; Pita, G.; Rodeghiero, M.; Rodrigues, A.; Starr, G.; Stoy, Paul C.

    2011-01-01

    Basal ecosystem respiration rate (BR), the ecosystem respiration rate at a given temperature, is a common and important parameter in empirical models for quantifying ecosystem respiration (ER) globally. Numerous studies have indicated that BR varies in space. However, many empirical ER models still use a global constant BR largely due to the lack of a functional description for BR. In this study, we redefined BR to be ecosystem respiration rate at the mean annual temperature. To test the validity of this concept, we conducted a synthesis analysis using 276 site-years of eddy covariance data, from 79 research sites located at latitudes ranging from ∼3°S to ∼70°N. Results showed that mean annual ER rate closely matches ER rate at mean annual temperature. Incorporation of site-specific BR into global ER model substantially improved simulated ER compared to an invariant BR at all sites. These results confirm that ER at the mean annual temperature can be considered as BR in empirical models. A strong correlation was found between the mean annual ER and mean annual gross primary production (GPP). Consequently, GPP, which is typically more accurately modeled, can be used to estimate BR. A light use efficiency GPP model (i.e., EC-LUE) was applied to estimate global GPP, BR and ER with input data from MERRA (Modern Era Retrospective-Analysis for Research and Applications) and MODIS (Moderate resolution Imaging Spectroradiometer). The global ER was 103 Pg C yr −1, with the highest respiration rate over tropical forests and the lowest value in dry and high-latitude areas.

  11. Model Dinamik Penularan Human Immunodeficiency Virus (HIV)

    OpenAIRE

    Sutimin, Sutimin; Imamudin, Imamudin

    2009-01-01

    -Human Immunodeficiency Virus (HIV) adalah virus yang dapat merusak sistem kekebalan tubuh manusia Virus HIV dapat menyerang orang yang rentan ketika orang yang rentan itu melakukan kontak dengan penderita virus HIV hingga terinfeksi virus HIV pada akhirnya dapat menderita AIDS atau seropositif non-AIDS. Dengan asumsi-asumsi tentang penularan virus HIV dapat diformulasikan suatu model matematika tentang perpindahan antar orang-orang rentan ke infeksi HIV, penderita AIDS dan seropositif non-A...

  12. Modeling human influenza infection in the laboratory

    Directory of Open Access Journals (Sweden)

    Radigan KA

    2015-08-01

    Full Text Available Kathryn A Radigan,1 Alexander V Misharin,2 Monica Chi,1 GR Scott Budinger11Division of Pulmonary and Critical Care Medicine, 2Division of Rheumatology, Northwestern University Feinberg School of Medicine, Chicago, IL, USAAbstract: Influenza is the leading cause of death from an infectious cause. Because of its clinical importance, many investigators use animal models to understand the biologic mechanisms of influenza A virus replication, the immune response to the virus, and the efficacy of novel therapies. This review will focus on the biosafety, biosecurity, and ethical concerns that must be considered in pursuing influenza research, in addition to focusing on the two animal models – mice and ferrets – most frequently used by researchers as models of human influenza infection.Keywords: mice, ferret, influenza, animal model, biosafety

  13. Optimization of experimental human leukemia models (review

    Directory of Open Access Journals (Sweden)

    D. D. Pankov

    2012-01-01

    Full Text Available Actual problem of assessing immunotherapy prospects including antigenpecific cell therapy using animal models was covered in this review.Describe the various groups of currently existing animal models and methods of their creating – from different immunodeficient mice to severalvariants of tumor cells engraftment in them. The review addresses the possibility of tumor stem cells studying using mouse models for the leukemia treatment with adoptive cell therapy including WT1. Also issues of human leukemia cells migration and proliferation in a mice withdifferent immunodeficiency degree are discussed. To assess the potential immunotherapy efficacy comparison of immunodeficient mouse model with clinical situation in oncology patients after chemotherapy is proposed.

  14. Human responses to augmented virtual scaffolding models.

    Science.gov (United States)

    Hsiao, Hongwei; Simeonov, Peter; Dotson, Brian; Ammons, Douglas; Kau, Tsui-Ying; Chiou, Sharon

    2005-08-15

    This study investigated the effect of adding real planks, in virtual scaffolding models of elevation, on human performance in a surround-screen virtual reality (SSVR) system. Twenty-four construction workers and 24 inexperienced controls performed walking tasks on real and virtual planks at three virtual heights (0, 6 m, 12 m) and two scaffolding-platform-width conditions (30, 60 cm). Gait patterns, walking instability measurements and cardiovascular reactivity were assessed. The results showed differences in human responses to real vs. virtual planks in walking patterns, instability score and heart-rate inter-beat intervals; it appeared that adding real planks in the SSVR virtual scaffolding model enhanced the quality of SSVR as a human - environment interface research tool. In addition, there were significant differences in performance between construction workers and the control group. The inexperienced participants were more unstable as compared to construction workers. Both groups increased their stride length with repetitions of the task, indicating a possibly confidence- or habit-related learning effect. The practical implications of this study are in the adoption of augmented virtual models of elevated construction environments for injury prevention research, and the development of programme for balance-control training to reduce the risk of falls at elevation before workers enter a construction job.

  15. Modeling Oxygen Transport in the Human Placenta

    Science.gov (United States)

    Serov, Alexander; Filoche, Marcel; Salafia, Carolyn; Grebenkov, Denis

    Efficient functioning of the human placenta is crucial for the favorable pregnancy outcome. We construct a 3D model of oxygen transport in the placenta based on its histological cross-sections. The model accounts for both diffusion and convention of oxygen in the intervillous space and allows one to estimate oxygen uptake of a placentone. We demonstrate the existence of an optimal villi density maximizing the uptake and explain it as a trade-off between the incoming oxygen flow and the absorbing villous surface. Calculations performed for arbitrary shapes of fetal villi show that only two geometrical characteristics - villi density and the effective villi radius - are required to predict fetal oxygen uptake. Two combinations of physiological parameters that determine oxygen uptake are also identified: maximal oxygen inflow of a placentone and the Damköhler number. An automatic image analysis method is developed and applied to 22 healthy placental cross-sections demonstrating that villi density of a healthy human placenta lies within 10% of the optimal value, while overall geometry efficiency is rather low (around 30-40%). In a perspective, the model can constitute the base of a reliable tool of post partum oxygen exchange efficiency assessment in the human placenta. Also affiliated with Department of Chemistry and Biochemistry, UCLA, Los Angeles, CA 90095, USA.

  16. Effects of respirator use on worker performance

    Energy Technology Data Exchange (ETDEWEB)

    Cardarelli, R. [Yankee Atomic Electric Co., Bolton, MA (United States)

    1995-03-01

    In 1993, EPRI funded Yankee Atomic Electric Company to examine the effects of respirator use on worker efficiency. Phase I of Yankee`s effort was to develop a study design to determine respirator effects. Given success in Phase I, a larger population will be tested to determine if a stasitically significant respirator effect on performance can be measured. This paper summarizes the 1993 EPRI/Yankee Respirator Effects of Pilot Study, and describes the study design for the 1994 EPRI/Yankee Respirator Study to be conducted at the Oyster Creek Nuclear Power Plant. Also described is a summary of respirator effect studies that have been conducted during the last ten (10) years.

  17. Respirators: Supervisors Self-Study #43442

    Energy Technology Data Exchange (ETDEWEB)

    Chochoms, Michael [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-04-20

    This course, Respirators: Supervisors Self-Study (#43442), addresses training requirements for supervisors of respirator wearers as specified by the American National Standard Institute (ANSI) Standard for Respiratory Protection, ANSI Z88.2, and as incorporated by reference in the Department of Energy (DOE) Worker Health and Safety Rule, 10 Code of Federal Regulations (CFR) 851. This course also presents the responsibilities of supervisors of respirator wearers at Los Alamos National Laboratory (LANL).

  18. Diel hysteresis between soil respiration and soil temperature in a biological soil crust covered desert ecosystem.

    Science.gov (United States)

    Guan, Chao; Li, Xinrong; Zhang, Peng; Chen, Yongle

    2018-01-01

    Soil respiration induced by biological soil crusts (BSCs) is an important process in the carbon (C) cycle in arid and semi-arid ecosystems, where vascular plants are restricted by the harsh environment, particularly the limited soil moisture. However, the interaction between temperature and soil respiration remains uncertain because of the number of factors that control soil respiration, including temperature and soil moisture, especially in BSC-dominated areas. In this study, the soil respiration in moss-dominated crusts and lichen-dominated crusts was continuously measured using an automated soil respiration system over a one-year period from November 2015 to October 2016 in the Shapotou region of the Tengger Desert, northern China. The results indicated that over daily cycles, the half-hourly soil respiration rates in both types of BSC-covered areas were commonly related to the soil temperature. The observed diel hysteresis between the half-hourly soil respiration rates and soil temperature in the BSC-covered areas was limited by nonlinearity loops with semielliptical shapes, and soil temperature often peaked later than the half-hourly soil respiration rates in the BSC-covered areas. The average lag times between the half-hourly soil respiration rates and soil temperature for both types of BSC-covered areas were two hours over the diel cycles, and they were negatively and linearly related to the volumetric soil water content. Our results highlight the diel hysteresis phenomenon that occurs between soil respiration rates and soil temperatures in BSC-covered areas and the negative response of this phenomenon to soil moisture, which may influence total C budget evaluations. Therefore, the interactive effects of soil temperature and moisture on soil respiration in BSC-covered areas should be considered in global carbon cycle models of desert ecosystems.

  19. A dynamic model of human physiology

    Science.gov (United States)

    Green, Melissa; Kaplan, Carolyn; Oran, Elaine; Boris, Jay

    2010-11-01

    To study the systems-level transport in the human body, we develop the Computational Man (CMAN): a set of one-dimensional unsteady elastic flow simulations created to model a variety of coupled physiological systems including the circulatory, respiratory, excretory, and lymphatic systems. The model systems are collapsed from three spatial dimensions and time to one spatial dimension and time by assuming axisymmetric vessel geometry and a parabolic velocity profile across the cylindrical vessels. To model the actions of a beating heart or expanding lungs, the flow is driven by user-defined changes to the equilibrium areas of the elastic vessels. The equations are then iteratively solved for pressure, area, and average velocity. The model is augmented with valves and contractions to resemble the biological structure of the different systems. CMAN will be used to track material transport throughout the human body for diagnostic and predictive purposes. Parameters will be adjustable to match those of individual patients. Validation of CMAN has used both higher-dimensional simulations of similar geometries and benchmark measurement from medical literature.

  20. The Five Key Questions of Human Performance Modeling.

    Science.gov (United States)

    Wu, Changxu

    2018-01-01

    Via building computational (typically mathematical and computer simulation) models, human performance modeling (HPM) quantifies, predicts, and maximizes human performance, human-machine system productivity and safety. This paper describes and summarizes the five key questions of human performance modeling: 1) Why we build models of human performance; 2) What the expectations of a good human performance model are; 3) What the procedures and requirements in building and verifying a human performance model are; 4) How we integrate a human performance model with system design; and 5) What the possible future directions of human performance modeling research are. Recent and classic HPM findings are addressed in the five questions to provide new thinking in HPM's motivations, expectations, procedures, system integration and future directions.

  1. Human reliability data collection and modelling

    International Nuclear Information System (INIS)

    1991-09-01

    The main purpose of this document is to review and outline the current state-of-the-art of the Human Reliability Assessment (HRA) used for quantitative assessment of nuclear power plants safe and economical operation. Another objective is to consider Human Performance Indicators (HPI) which can alert plant manager and regulator to departures from states of normal and acceptable operation. These two objectives are met in the three sections of this report. The first objective has been divided into two areas, based on the location of the human actions being considered. That is, the modelling and data collection associated with control room actions are addressed first in chapter 1 while actions outside the control room (including maintenance) are addressed in chapter 2. Both chapters 1 and 2 present a brief outline of the current status of HRA for these areas, and major outstanding issues. Chapter 3 discusses HPI. Such performance indicators can signal, at various levels, changes in factors which influence human performance. The final section of this report consists of papers presented by the participants of the Technical Committee Meeting. A separate abstract was prepared for each of these papers. Refs, figs and tabs

  2. Zebrafish Models for Human Acute Organophosphorus Poisoning.

    Science.gov (United States)

    Faria, Melissa; Garcia-Reyero, Natàlia; Padrós, Francesc; Babin, Patrick J; Sebastián, David; Cachot, Jérôme; Prats, Eva; Arick Ii, Mark; Rial, Eduardo; Knoll-Gellida, Anja; Mathieu, Guilaine; Le Bihanic, Florane; Escalon, B Lynn; Zorzano, Antonio; Soares, Amadeu M V M; Raldúa, Demetrio

    2015-10-22

    Terrorist use of organophosphorus-based nerve agents and toxic industrial chemicals against civilian populations constitutes a real threat, as demonstrated by the terrorist attacks in Japan in the 1990 s or, even more recently, in the Syrian civil war. Thus, development of more effective countermeasures against acute organophosphorus poisoning is urgently needed. Here, we have generated and validated zebrafish models for mild, moderate and severe acute organophosphorus poisoning by exposing zebrafish larvae to different concentrations of the prototypic organophosphorus compound chlorpyrifos-oxon. Our results show that zebrafish models mimic most of the pathophysiological mechanisms behind this toxidrome in humans, including acetylcholinesterase inhibition, N-methyl-D-aspartate receptor activation, and calcium dysregulation as well as inflammatory and immune responses. The suitability of the zebrafish larvae to in vivo high-throughput screenings of small molecule libraries makes these models a valuable tool for identifying new drugs for multifunctional drug therapy against acute organophosphorus poisoning.

  3. Plastron Respiration Using Commercial Fabrics

    Directory of Open Access Journals (Sweden)

    Shaun Atherton

    2014-01-01

    Full Text Available A variety of insect and arachnid species are able to remain submerged in water indefinitely using plastron respiration. A plastron is a surface-retained film of air produced by surface morphology that acts as an oxygen-carbon dioxide exchange surface. Many highly water repellent and hydrophobic surfaces when placed in water exhibit a silvery sheen which is characteristic of a plastron. In this article, the hydrophobicity of a range of commercially available water repellent fabrics and polymer membranes is investigated, and how the surface of the materials mimics this mechanism of underwater respiration is demonstrated allowing direct extraction of oxygen from oxygenated water. The coverage of the surface with the plastron air layer was measured using confocal microscopy. A zinc/oxygen cell is used to consume oxygen within containers constructed from the different membranes, and the oxygen consumed by the cell is compared to the change in oxygen concentration as measured by an oxygen probe. By comparing the membranes to an air-tight reference sample, it was found that the membranes facilitated oxygen transfer from the water into the container, with the most successful membrane showing a 1.90:1 ratio between the cell oxygen consumption and the change in concentration within the container.

  4. The quantitative modelling of human spatial habitability

    Science.gov (United States)

    Wise, J. A.

    1985-01-01

    A model for the quantitative assessment of human spatial habitability is presented in the space station context. The visual aspect assesses how interior spaces appear to the inhabitants. This aspect concerns criteria such as sensed spaciousness and the affective (emotional) connotations of settings' appearances. The kinesthetic aspect evaluates the available space in terms of its suitability to accommodate human movement patterns, as well as the postural and anthrometric changes due to microgravity. Finally, social logic concerns how the volume and geometry of available space either affirms or contravenes established social and organizational expectations for spatial arrangements. Here, the criteria include privacy, status, social power, and proxemics (the uses of space as a medium of social communication).

  5. The study of human venous system dynamics using hybrid computer modeling

    Science.gov (United States)

    Snyder, M. F.; Rideout, V. C.

    1972-01-01

    A computer-based model of the cardiovascular system was created emphasizing effects on the systemic venous system. Certain physiological aspects were emphasized: effects of heart rate, tilting, changes in respiration, and leg muscular contractions. The results from the model showed close correlation with findings previously reported in the literature.

  6. Wet meadow ecosystems contribute the majority of overwinter soil respiration from snow-scoured alpine tundra

    Science.gov (United States)

    Knowles, John F.; Blanken, Peter D.; Williams, Mark W.

    2016-04-01

    We measured soil respiration across a soil moisture gradient ranging from dry to wet snow-scoured alpine tundra soils throughout three winters and two summers. In the absence of snow accumulation, soil moisture variability was principally determined by the combination of mesotopographical hydrological focusing and shallow subsurface permeability, which resulted in a patchwork of comingled ecosystem types along a single alpine ridge. To constrain the subsequent carbon cycling variability, we compared three measures of effective diffusivity and three methods to calculate gradient method soil respiration from four typical vegetation communities. Overwinter soil respiration was primarily restricted to wet meadow locations, and a conservative estimate of the rate of overwinter soil respiration from snow-scoured wet meadow tundra was 69-90% of the maximum carbon dioxide (CO2) respired by seasonally snow-covered soils within this same catchment. This was attributed to higher overwinter soil temperatures at wet meadow locations relative to fellfield, dry meadow, and moist meadow communities, which supported liquid water and heterotrophic respiration throughout the winter. These results were corroborated by eddy covariance-based measurements that demonstrated an average of 272 g C m-2 overwinter carbon loss during the study period. As a result, we updated a conceptual model of soil respiration versus snow cover to express the potential for soil respiration variability from snow-scoured alpine tundra.

  7. Driver-response relationships between frontal EEG and respiration during affective audiovisual stimuli.

    Science.gov (United States)

    Kroupi, Eleni; Vesin, Jean-Marc; Ebrahimi, Touradj

    2013-01-01

    The complementary nature and the coordinative tendencies of brain and body are essential to the way humans function. Although static features from brain and body signals have been shown to reflect emotions, the dynamic interrelation of the two systems during emotional processes is still in its infancy. This study aims at investigating the way brain signals captured by Electroencephalography (EEG) and bodily responses reflected in respiration interact when watching music clips. A non-linear measure is applied to frontal EEG and respiration to determine the driver/driven relationship between these two modalities. The results reveal a unidirectional dependence from respiration to EEG which adds evidence to the bodily-feedback theory.

  8. Modelling human eye under blast loading.

    Science.gov (United States)

    Esposito, L; Clemente, C; Bonora, N; Rossi, T

    2015-01-01

    Primary blast injury (PBI) is the general term that refers to injuries resulting from the mere interaction of a blast wave with the body. Although few instances of primary ocular blast injury, without a concomitant secondary blast injury from debris, are documented, some experimental studies demonstrate its occurrence. In order to investigate PBI to the eye, a finite element model of the human eye using simple constitutive models was developed. The material parameters were calibrated by a multi-objective optimisation performed on available eye impact test data. The behaviour of the human eye and the dynamics of mechanisms occurring under PBI loading conditions were modelled. For the generation of the blast waves, different combinations of explosive (trinitrotoluene) mass charge and distance from the eye were analysed. An interpretation of the resulting pressure, based on the propagation and reflection of the waves inside the eye bulb and orbit, is proposed. The peculiar geometry of the bony orbit (similar to a frustum cone) can induce a resonance cavity effect and generate a pressure standing wave potentially hurtful for eye tissues.

  9. Modeling human comprehension of data visualizations

    Energy Technology Data Exchange (ETDEWEB)

    Matzen, Laura E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Haass, Michael Joseph [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Divis, Kristin Marie [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Wilson, Andrew T. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-09-01

    This project was inspired by two needs. The first is a need for tools to help scientists and engineers to design effective data visualizations for communicating information, whether to the user of a system, an analyst who must make decisions based on complex data, or in the context of a technical report or publication. Most scientists and engineers are not trained in visualization design, and they could benefit from simple metrics to assess how well their visualization's design conveys the intended message. In other words, will the most important information draw the viewer's attention? The second is the need for cognition-based metrics for evaluating new types of visualizations created by researchers in the information visualization and visual analytics communities. Evaluating visualizations is difficult even for experts. However, all visualization methods and techniques are intended to exploit the properties of the human visual system to convey information efficiently to a viewer. Thus, developing evaluation methods that are rooted in the scientific knowledge of the human visual system could be a useful approach. In this project, we conducted fundamental research on how humans make sense of abstract data visualizations, and how this process is influenced by their goals and prior experience. We then used that research to develop a new model, the Data Visualization Saliency Model, that can make accurate predictions about which features in an abstract visualization will draw a viewer's attention. The model is an evaluation tool that can address both of the needs described above, supporting both visualization research and Sandia mission needs.

  10. Pore-scale investigation on the response of heterotrophic respiration to moisture conditions in heterogeneous soils

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Zhifeng; Liu, Chongxuan; Todd-Brown, Katherine E.; Liu, Yuanyuan; Bond-Lamberty, Ben; Bailey, Vanessa L.

    2016-11-15

    The relationship between microbial respiration rate and soil moisture content is an important property for understanding and predicting soil organic carbon degradation, CO2 production and emission, and their subsequent effects on climate change. This paper reports a pore-scale modeling study to investigate the response of heterotrophic respiration to moisture conditions in soils and to evaluate various factors that affect this response. X-ray computed tomography was used to derive soil pore structures, which were then used for pore-scale model investigation. The pore-scale results were then averaged to calculate the effective respiration rates as a function of water content in soils. The calculated effective respiration rate first increases and then decreases with increasing soil water content, showing a maximum respiration rate at water saturation degree of 0.75 that is consistent with field and laboratory observations. The relationship between the respiration rate and moisture content is affected by various factors, including pore-scale organic carbon bioavailability, the rate of oxygen delivery, soil pore structure and physical heterogeneity, soil clay content, and microbial drought resistivity. Simulations also illustrates that a larger fraction of CO2 produced from microbial respiration can be accumulated inside soil cores under higher saturation conditions, implying that CO2 flux measured on the top of soil cores may underestimate or overestimate true soil respiration rates under dynamic moisture conditions. Overall, this study provides mechanistic insights into the soil respiration response to the change in moisture conditions, and reveals a complex relationship between heterotrophic microbial respiration rate and moisture content in soils that is affected by various hydrological, geochemical, and biophysical factors.

  11. Virtual pharmacokinetic model of human eye.

    Science.gov (United States)

    Kotha, Sreevani; Murtomäki, Lasse

    2014-07-01

    A virtual pharmacokinetic 3D model of the human eye is built using Comsol Multiphysics® software, which is based on the Finite Element Method (FEM). The model considers drug release from a polymer patch placed on sclera. The model concentrates on the posterior part of the eye, retina being the target tissue, and comprises the choroidal blood flow, partitioning of the drug between different tissues and active transport at the retina pigment epithelium (RPE)-choroid boundary. Although most straightforward, in order to check the mass balance, no protein binding or metabolism is yet included. It appeared that the most important issue in obtaining reliable simulation results is the finite element mesh, while time stepping has hardly any significance. Simulations were extended to 100,000 s. The concentration of a drug is shown as a function of time at various points of retina, as well as its average value, varying several parameters in the model. This work demonstrates how anybody with basic knowledge of calculus is able to build physically meaningful models of quite complex biological systems. Copyright © 2014 Elsevier Inc. All rights reserved.

  12. Dengue human infection models supporting drug development.

    Science.gov (United States)

    Whitehorn, James; Van, Vinh Chau Nguyen; Simmons, Cameron P

    2014-06-15

    Dengue is a arboviral infection that represents a major global health burden. There is an unmet need for effective dengue therapeutics to reduce symptoms, duration of illness and incidence of severe complications. Here, we consider the merits of a dengue human infection model (DHIM) for drug development. A DHIM could allow experimentally controlled studies of candidate therapeutics in preselected susceptible volunteers, potentially using smaller sample sizes than trials that recruited patients with dengue in an endemic country. In addition, the DHIM would assist the conduct of intensive pharmacokinetic and basic research investigations and aid in determining optimal drug dosage. Furthermore, a DHIM could help establish proof of concept that chemoprophylaxis against dengue is feasible. The key challenge in developing the DHIM for drug development is to ensure the model reliably replicates the typical clinical and laboratory features of naturally acquired, symptomatic dengue. © The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America.

  13. Human factors engineering program review model

    International Nuclear Information System (INIS)

    1994-07-01

    The staff of the Nuclear Regulatory Commission is performing nuclear power plant design certification reviews based on a design process plan that describes the human factors engineering (HFE) program elements that are necessary and sufficient to develop an acceptable detailed design specification and an acceptable implemented design. There are two principal reasons for this approach. First, the initial design certification applications submitted for staff review did not include detailed design information. Second, since human performance literature and industry experiences have shown that many significant human factors issues arise early in the design process, review of the design process activities and results is important to the evaluation of an overall design. However, current regulations and guidance documents do not address the criteria for design process review. Therefore, the HFE Program Review Model (HFE PRM) was developed as a basis for performing design certification reviews that include design process evaluations as well as review of the final design. A central tenet of the HFE PRM is that the HFE aspects of the plant should be developed, designed, and evaluated on the basis of a structured top-down system analysis using accepted HFE principles. The HFE PRM consists of ten component elements. Each element in divided into four sections: Background, Objective, Applicant Submittals, and Review Criteria. This report describes the development of the HFE PRM and gives a detailed description of each HFE review element

  14. A human neurodevelopmental model for Williams syndrome.

    Science.gov (United States)

    Chailangkarn, Thanathom; Trujillo, Cleber A; Freitas, Beatriz C; Hrvoj-Mihic, Branka; Herai, Roberto H; Yu, Diana X; Brown, Timothy T; Marchetto, Maria C; Bardy, Cedric; McHenry, Lauren; Stefanacci, Lisa; Järvinen, Anna; Searcy, Yvonne M; DeWitt, Michelle; Wong, Wenny; Lai, Philip; Ard, M Colin; Hanson, Kari L; Romero, Sarah; Jacobs, Bob; Dale, Anders M; Dai, Li; Korenberg, Julie R; Gage, Fred H; Bellugi, Ursula; Halgren, Eric; Semendeferi, Katerina; Muotri, Alysson R

    2016-08-18

    Williams syndrome is a genetic neurodevelopmental disorder characterized by an uncommon hypersociability and a mosaic of retained and compromised linguistic and cognitive abilities. Nearly all clinically diagnosed individuals with Williams syndrome lack precisely the same set of genes, with breakpoints in chromosome band 7q11.23 (refs 1-5). The contribution of specific genes to the neuroanatomical and functional alterations, leading to behavioural pathologies in humans, remains largely unexplored. Here we investigate neural progenitor cells and cortical neurons derived from Williams syndrome and typically developing induced pluripotent stem cells. Neural progenitor cells in Williams syndrome have an increased doubling time and apoptosis compared with typically developing neural progenitor cells. Using an individual with atypical Williams syndrome, we narrowed this cellular phenotype to a single gene candidate, frizzled 9 (FZD9). At the neuronal stage, layer V/VI cortical neurons derived from Williams syndrome were characterized by longer total dendrites, increased numbers of spines and synapses, aberrant calcium oscillation and altered network connectivity. Morphometric alterations observed in neurons from Williams syndrome were validated after Golgi staining of post-mortem layer V/VI cortical neurons. This model of human induced pluripotent stem cells fills the current knowledge gap in the cellular biology of Williams syndrome and could lead to further insights into the molecular mechanism underlying the disorder and the human social brain.

  15. Human factors engineering program review model

    Energy Technology Data Exchange (ETDEWEB)

    1994-07-01

    The staff of the Nuclear Regulatory Commission is performing nuclear power plant design certification reviews based on a design process plan that describes the human factors engineering (HFE) program elements that are necessary and sufficient to develop an acceptable detailed design specification and an acceptable implemented design. There are two principal reasons for this approach. First, the initial design certification applications submitted for staff review did not include detailed design information. Second, since human performance literature and industry experiences have shown that many significant human factors issues arise early in the design process, review of the design process activities and results is important to the evaluation of an overall design. However, current regulations and guidance documents do not address the criteria for design process review. Therefore, the HFE Program Review Model (HFE PRM) was developed as a basis for performing design certification reviews that include design process evaluations as well as review of the final design. A central tenet of the HFE PRM is that the HFE aspects of the plant should be developed, designed, and evaluated on the basis of a structured top-down system analysis using accepted HFE principles. The HFE PRM consists of ten component elements. Each element in divided into four sections: Background, Objective, Applicant Submittals, and Review Criteria. This report describes the development of the HFE PRM and gives a detailed description of each HFE review element.

  16. Respirators: APR Issuer Self Study 33461

    Energy Technology Data Exchange (ETDEWEB)

    Chochoms, Michael [Los Alamos National Laboratory

    2016-07-13

    Respirators: APR Issuer Self-Study (course 33461) is designed to introduce and familiarize employees selected as air-purifying respirator (APR) issuers at Los Alamos National Laboratory (LANL) with the responsibilities, limitations, procedures, and resources for issuing APRs at LANL. The goal is to enable these issuers to consistently provide proper, functioning APRs to authorized users

  17. Students' Chemical Knowledge in Photosynthesis and Respiration ...

    African Journals Online (AJOL)

    Students' Chemical Knowledge in Photosynthesis and Respiration in Port Harcourt Metropolis of Rivers State of Nigeria. ... African Journal of Chemical Education ... Photosynthesis-Respiration Chemical Reaction Test (P-RCRT) and PLDRT-essay test on light and dark reactions of photosynthesis and fate of glucose in ...

  18. Management effects on European cropland respiration

    NARCIS (Netherlands)

    Eugster, W.; Moffat, A.M.; Ceschia, E.; Jacobs, C.M.J.; Moors, E.J.; Jans, W.W.P.

    2010-01-01

    Increases in respiration rates following management activities in croplands are considered a relevant anthropogenic source of CO2. In this paper, we quantify the impact of management events on cropland respiration fluxes of CO2 as they occur under current climate and management conditions. Our

  19. Respirable concrete dust--silicosis hazard in the construction industry.

    Science.gov (United States)

    Linch, Kenneth D

    2002-03-01

    Concrete is an extremely important part of the infrastructure of modern life and must be replaced as it ages. Many of the methods of removing, repairing, or altering existing concrete structures have the potential for producing vast quantities of respirable dust. Since crystalline silica in the form of quartz is a major component of concrete, airborne respirable quartz dust may be produced during construction work involving the disturbance of concrete, thereby producing a silicosis hazard for exposed workers. Silicosis is a debilitating and sometimes fatal lung disease resulting from breathing microscopic particles of crystalline silica. Between 1992 and 1998, the National Institute for Occupational Safety and Health (NIOSH) made visits to construction projects where concrete was being mechanically disturbed in order to obtain data concerning respirable crystalline silica dust exposures. The construction activities studied included: abrasive blasting, concrete pavement sawing and drilling, and asphalt/concrete milling. Air samples of respirable dust were obtained using 10-mm nylon cyclone pre-separators, 37-mm polyvinyl chloride (PVC) filters, and constant-flow pumps calibrated at 1.7 L/min. In addition, high-volume respirable dust samples were obtained on 37-mm PVC filters using 1/2" metal cyclones (Sensidyne model 18) and constant-flow pumps calibrated at 9.0 L/min. Air sample analysis included total weight gain by gravimetric analysis according to NIOSH Analytical Method 600 and respirable crystalline silica (quartz and cristobalite) using x-ray diffraction, as per NIOSH Analytical Method 7500. For abrasive blasting of concrete structures, the respirable crystalline silica (quartz) concentration ranged up to 14.0 mg/m3 for a 96-minute sample resulting in an eight-hour time-weighted average (TWA) of 2.8 mg/m3. For drilling concrete highway pavement the respirable quartz concentrations ranged up to 4.4 mg/m3 for a 358-minute sample, resulting in an eight-hour TWA

  20. A modular approach to numerical human body modeling

    NARCIS (Netherlands)

    Forbes, P.A.; Griotto, G.; Rooij, L. van

    2007-01-01

    The choice of a human body model for a simulated automotive impact scenario must take into account both accurate model response and computational efficiency as key factors. This study presents a "modular numerical human body modeling" approach which allows the creation of a customized human body

  1. 42 CFR 84.1131 - Respirators; required components.

    Science.gov (United States)

    2010-10-01

    ..., and Mist; Pesticide; Paint Spray; Powered Air-Purifying High Efficiency Respirators and Combination Gas Masks § 84.1131 Respirators; required components. (a) Each respirator described in § 84.1130 shall...

  2. Respiration in neonate sea turtles.

    Science.gov (United States)

    Price, Edwin R; Paladino, Frank V; Strohl, Kingman P; Santidrián T, Pilar; Klann, Kenneth; Spotila, James R

    2007-03-01

    The pattern and control of respiration is virtually unknown in hatchling sea turtles. Using incubator-raised turtles, we measured oxygen consumption, frequency, tidal volume, and minute volume for leatherback (Dermochelys coriacea) and olive ridley (Lepidochelys olivacea) turtle hatchlings for the first six days after pipping. In addition, we tested the hatchlings' response to hypercapnic, hyperoxic, and hypoxic challenges over this time period. Hatchling sea turtles generally showed resting ventilation characteristics that are similar to those of adults: a single breath followed by a long respiratory pause, slow frequency, and high metabolic rate. With hypercapnic challenge, both species responded primarily by elevating respiratory frequency via a decrease in the non-ventilatory period. Leatherback resting tidal volume increased with age but otherwise, neither species' resting respiratory pattern nor response to gas challenge changed significantly over the first few days after hatching. At the time of nest emergence, sea turtles have achieved a respiratory pattern that is similar to that of actively diving adults.

  3. Sleep and Respiration in Microgravity

    Science.gov (United States)

    West, John B.; Elliott, Ann R.; Prisk, G. Kim; Paiva, Manuel

    2003-01-01

    Sleep is often reported to be of poor quality in microgravity, and studies on the ground have shown a strong relationship between sleep-disordered breathing and sleep disruption. During the 16-day Neurolab mission, we studied the influence of possible changes in respiratory function on sleep by performing comprehensive sleep recordings on the payload crew on four nights during the mission. In addition, we measured the changes in the ventilatory response to low oxygen and high carbon dioxide in the same subjects during the day, hypothesizing that changes in ventilatory control might affect respiration during sleep. Microgravity caused a large reduction in the ventilatory response to reduced oxygen. This is likely the result of an increase in blood pressure at the peripheral chemoreceptors in the neck that occurs when the normally present hydrostatic pressure gradient between the heart and upper body is abolished. This reduction was similar to that seen when the subjects were placed acutely in the supine position in one-G. In sharp contrast to low oxygen, the ventilatory response to elevated carbon dioxide was unaltered by microgravity or the supine position. Because of the similarities of the findings in microgravity and the supine position, it is unlikely that changes in ventilatory control alter respiration during sleep in microgravity. During sleep on the ground, there were a small number of apneas (cessation of breathing) and hypopneas (reduced breathing) in these normal subjects. During sleep in microgravity, there was a reduction in the number of apneas and hypopneas per hour compared to preflight. Obstructive apneas virtually disappeared in microgravity, suggesting that the removal of gravity prevents the collapse of upper airways during sleep. Arousals from sleep were reduced in microgravity compared to preflight, and virtually all of this reduction was as a result of a reduction in the number of arousals from apneas and hypopneas. We conclude that any sleep

  4. Residence time of carbon substrate for autotrophic respiration of a grassland ecosystem correlates with the carbohydrate status of its vegetation

    Science.gov (United States)

    Ostler, Ulrike; Lehmeier, Christoph A.; Schleip, Inga; Schnyder, Hans

    2016-04-01

    Ecosystem respiration is composed of two component fluxes: (1) autotrophic respiration, which comprises respiratory activity of plants and plant-associated microbes that feed on products of recent photosynthetic activity and (2) heterotrophic respiration of microbes that decompose organic matter. The mechanistic link between the availability of carbon (C) substrate for ecosystem respiration and its respiratory activity is not well understood, particularly in grasslands. Here, we explore, how the kinetic features of the supply system feeding autotrophic ecosystem respiration in a temperate humid pasture are related to the content of water-soluble carbohydrates and remobilizable protein (as potential respiratory substrates) in vegetation biomass. During each September 2006, May 2007 and September 2007, we continuously labeled 0.8 m2 pasture plots with 13CO2/12CO2 and observed ecosystem respiration and its tracer content every night during the 14-16 day long labeling periods. We analyzed the tracer kinetics with a pool model, which allowed us to precisely partition ecosystem respiration into its autotrophic and heterotrophic flux components. At the end of a labeling campaign, we harvested aboveground and belowground plant biomass and analyzed its non-structural C contents. Approximately half of ecosystem respiration did not release any significant amount of tracer during the labeling period and was hence characterized as heterotrophic. The other half of ecosystem respiration was autotrophic, with a mean residence time of C in the respiratory substrate pool between 2 and 6 d. Both the rate of autotrophic respiration and the turnover of its substrate supply pool were correlated with plant carbohydrate content, but not with plant protein content. These findings are in agreement with studies in controlled environments that revealed water-soluble carbohydrates as the main substrate and proteins as a marginal substrate for plant respiration under favorable growth conditions

  5. Potential demand for respirators and surgical masks during a hypothetical influenza pandemic in the United States.

    Science.gov (United States)

    Carias, Cristina; Rainisch, Gabriel; Shankar, Manjunath; Adhikari, Bishwa B; Swerdlow, David L; Bower, William A; Pillai, Satish K; Meltzer, Martin I; Koonin, Lisa M

    2015-05-01

    To inform planning for an influenza pandemic, we estimated US demand for N95 filtering facepiece respirators (respirators) by healthcare and emergency services personnel and need for surgical masks by pandemic patients seeking care. We used a spreadsheet-based model to estimate demand for 3 scenarios of respirator use: base case (usage approximately follows epidemic curve), intermediate demand (usage rises to epidemic peak and then remains constant), and maximum demand (all healthcare workers use respirators from pandemic onset). We assumed that in the base case scenario, up to 16 respirators would be required per day per intensive care unit patient and 8 per day per general ward patient. Outpatient healthcare workers and emergency services personnel would require 4 respirators per day. Patients would require 1.2 surgical masks per day. Assuming that 20% to 30% of the population would become ill, 1.7 to 3.5 billion respirators would be needed in the base case scenario, 2.6 to 4.3 billion in the intermediate demand scenario, and up to 7.3 billion in the maximum demand scenario (for all scenarios, between 0.1 and 0.4 billion surgical masks would be required for patients). For pandemics with a lower attack rate and fewer cases (eg, 2009-like pandemic), the number of respirators needed would be higher because the pandemic would have longer duration. Providing these numbers of respirators and surgical masks represents a logistic challenge for US public health agencies. Public health officials must urgently consider alternative use strategies for respirators and surgical masks during a pandemic that may vary from current practices. Published by Oxford University Press on behalf of the Infectious Diseases Society of America 2015. This work is written by (a) US Government employee(s) and is in the public domain in the US.

  6. Monitoring and modeling human interactions with ecosystems

    Science.gov (United States)

    Milesi, Cristina

    With rapidly increasing consumption rates and global population, there is a growing interest in understanding how to balance human activities with the other components of the Earth system. Humans alter ecosystem functioning with land cover changes, greenhouse gas emissions and overexploitation of natural resources. On the other side, climate and its inherent interannual variability drive global Net Primary Productivity (NPP), the base of energy for all trophic levels, shaping humans' distribution on the land surface and their sensitivity to natural and accelerated patterns of variation in ecosystem processes. In this thesis, I analyzed anthropogenic influences on ecosystems and ecosystems impacts on humans through a multi-scale approach. Anthropogenic influences were analyzed with a special focus on urban ecosystems, the living environment of nearly half of the global population and almost 90% of the population in the industrialized countries. A poorly quantified aspect of urban ecosystems is the biogeochemistry of urban vegetation, intensively managed through fertilization and irrigation. In chapter 1, adapting the ecosystem model Biome-BGC, I simulated the growth of turf grasses across the United States, and estimated their potential impact on the continental water and carbon budget. Using a remote sensing-based approach, I also developed a methodology to estimate the impact of land cover changes due to urbanization on the regional photosynthetic capacity (chapter 2), finding that low-density urbanization can retain high levels of net primary productivity, although at the expense of inefficient sprawl. One of the feedbacks of urbanization is the urban heat island effect, which I analyzed in conjunction with a remote sensing based estimate of fractional impervious surface area, showing how this is related to increases in land surface temperatures, independently from geographic location and population density (chapter 3). Finally, in chapter 4, I described the

  7. Classification of soil respiration in areas of sugarcane renewal using decision tree

    Directory of Open Access Journals (Sweden)

    Camila Viana Vieira Farhate

    Full Text Available ABSTRACT: The use of data mining is a promising alternative to predict soil respiration from correlated variables. Our objective was to build a model using variable selection and decision tree induction to predict different levels of soil respiration, taking into account physical, chemical and microbiological variables of soil as well as precipitation in renewal of sugarcane areas. The original dataset was composed of 19 variables (18 independent variables and one dependent (or response variable. The variable-target refers to soil respiration as the target classification. Due to a large number of variables, a procedure for variable selection was conducted to remove those with low correlation with the variable-target. For that purpose, four approaches of variable selection were evaluated: no variable selection, correlation-based feature selection (CFS, chisquare method (χ2 and Wrapper. To classify soil respiration, we used the decision tree induction technique available in the Weka software package. Our results showed that data mining techniques allow the development of a model for soil respiration classification with accuracy of 81 %, resulting in a knowledge base composed of 27 rules for prediction of soil respiration. In particular, the wrapper method for variable selection identified a subset of only five variables out of 18 available in the original dataset, and they had the following order of influence in determining soil respiration: soil temperature > precipitation > macroporosity > soil moisture > potential acidity.

  8. Forest soil respiration rate and delta13C is regulated by recent above ground weather conditions.

    Science.gov (United States)

    Ekblad, Alf; Boström, Björn; Holm, Anders; Comstedt, Daniel

    2005-03-01

    Soil respiration, a key component of the global carbon cycle, is a major source of uncertainty when estimating terrestrial carbon budgets at ecosystem and higher levels. Rates of soil and root respiration are assumed to be dependent on soil temperature and soil moisture yet these factors often barely explain half the seasonal variation in soil respiration. We here found that soil moisture (range 16.5-27.6% of dry weight) and soil temperature (range 8-17.5 degrees C) together explained 55% of the variance (cross-validated explained variance; Q2) in soil respiration rate (range 1.0-3.4 micromol C m(-2) s(-1)) in a Norway spruce (Picea abies) forest. We hypothesised that this was due to that the two components of soil respiration, root respiration and decomposition, are governed by different factors. We therefore applied PLS (partial least squares regression) multivariate modelling in which we, together with below ground temperature and soil moisture, used the recent above ground air temperature and air humidity (vapour pressure deficit, VPD) conditions as x-variables. We found that air temperature and VPD data collected 1-4 days before respiration measurements explained 86% of the seasonal variation in the rate of soil respiration. The addition of soil moisture and soil temperature to the PLS-models increased the Q2 to 93%. delta13C analysis of soil respiration supported the hypotheses that there was a fast flux of photosynthates to root respiration and a dependence on recent above ground weather conditions. Taken together, our results suggest that shoot activities the preceding 1-6 days influence, to a large degree, the rate of root and soil respiration. We propose this above ground influence on soil respiration to be proportionally largest in the middle of the growing season and in situations when there is large day-to-day shifts in the above ground weather conditions. During such conditions soil temperature may not exert the major control on root respiration.

  9. Ecosystem Respiration in an Undisturbed, Old-Growth, Temperate Rain Forest

    Science.gov (United States)

    Hunt, J. E.; Walcroft, A. S.; McSeveny, T. M.; Rogers, G. N.; Whitehead, D.

    2008-12-01

    Old-growth forests are usually close to carbon neutral, and climate change may push them towards becoming net carbon sources. Ecosystem carbon exchange and its component fluxes, were measured in a temperate rainforest in South Westland, New Zealand. The forest, which receives over 3 m of rain a year, is dominated by 400 year-old podocarp trees, and is on a low nutrient, acidic, peat soil. Nighttime respiration measurements using eddy covariance were problematic due to katabatic induced CO2 drainage flows near the ground and low turbulence. Instead of the friction velocity filtering technique, we used the maximum eddy flux within a few hours of sunset to derive a function relating nighttime ecosystem respiration to soil temperature. The function was then used to calculate respiration for the nighttime periods. Soil respiration was measured at regular intervals during the growing season. Soil temperature was regulated by incoming radiation and changes in the soil heat capacity. The water table was typically only 160 mm below the ground surface. Soil respiration (mean = 2.9 μmol m-2 s-1) increased strongly with both an increase in soil temperature and an increase in the depth to the water table, and accounted for approximately 50% of ecosystem respiration. Changes in the water table depth caused by altered rainfall regime, evaporation and drainage are likely to have a significant effect on the soil respiration rate and carbon balance of this old-growth forest. Foliage and stem respiration were also measured and integrated to the canopy scale using a model. The model was then used to decompose ecosystem respiration measurements into its components. A combination of measured and modelled data indicates that the ecosystem is a net source for carbon (-0.34 kg C m&-2 yr-1).

  10. Modeling and remodeling of human extraction sockets.

    Science.gov (United States)

    Trombelli, Leonardo; Farina, Roberto; Marzola, Andrea; Bozzi, Leopoldo; Liljenberg, Birgitta; Lindhe, Jan

    2008-07-01

    The available studies on extraction wound repair in humans are affected by significant limitations and have failed to evaluate tissue alterations occurring in all compartments of the hard tissue defect. To monitor during a 6-month period the healing of human extraction sockets and include a semi-quantitative analysis of tissues and cell populations involved in various stages of the processes of modeling/remodeling. Twenty-seven biopsies, representative of the early (2-4 weeks, n=10), intermediate (6-8 weeks, n=6), and late phase (12-24 weeks, n=11) of healing, were collected and analysed. Granulation tissue that was present in comparatively large amounts in the early healing phase of socket healing, was in the interval between the early and intermediate observation phase replaced with provisional matrix and woven bone. The density of vascular structures and macrophages slowly decreased from 2 to 4 weeks over time. The presence of osteoblasts peaked at 6-8 weeks and remained almost stable thereafter; a small number of osteoclasts were present in a few specimens at each observation interval. The present findings demonstrated that great variability exists in man with respect to hard tissue formation within extraction sockets. Thus, whereas a provisional connective tissue consistently forms within the first weeks of healing, the interval during which mineralized bone is laid down is much less predictable.

  11. Molecular Modeling of Prion Transmission to Humans

    Directory of Open Access Journals (Sweden)

    Etienne Levavasseur

    2014-10-01

    Full Text Available Using different prion strains, such as the variant Creutzfeldt-Jakob disease agent and the atypical bovine spongiform encephalopathy agents, and using transgenic mice expressing human or bovine prion protein, we assessed the reliability of protein misfolding cyclic amplification (PMCA to model interspecies and genetic barriers to prion transmission. We compared our PMCA results with in vivo transmission data characterized by attack rates, i.e., the percentage of inoculated mice that developed the disease. Using 19 seed/substrate combinations, we observed that a significant PMCA amplification was only obtained when the mouse line used as substrate is susceptible to the corresponding strain. Our results suggest that PMCA provides a useful tool to study genetic barriers to transmission and to study the zoonotic potential of emerging prion strains.

  12. Modeling and suppression of respiration induced B0-fluctuations in non-balanced steady-state free precession sequences at 7 Tesla.

    Science.gov (United States)

    Goa, Pål Erik; Poser, Benedikt Andreas; Barth, Markus

    2013-08-01

    To develop and evaluate a model for describing the S1 (S+) and S2 (S-) phase in the presence of off-resonance frequency fluctuations, and to evaluate the performance of a novel interleaved navigator echo scheme. Using the extended phase graph model, a linear phase term was added to the evolution of transverse states. An approximation for the total S2 phase was derived with one fit parameter τl, which serves as an effective lifetime of the S2 signal. The model was evaluated using synthetic and in vivo phase evolution data. In addition, a novel interleaved phase correction scheme for the nb-SSFP sequence was applied to BOLD-fMRI data, and the number of activated voxels before and after phase correction was determined. The phases of S1 and S2 signals are significantly different from each other. The proposed nb-SSFP phase model provided a good description of the measured phase evolution data, and the approximate model for the S2 phase provided both at good fit to the data, as well as an effective lifetime of the S2 signal. In some subjects the phase contribution from older pathways was underestimated. In the BOLD-fMRI data, a twofold increase of the number of activated voxels for the S2 signal was observed, compared to no correction and a conventional navigator echo method. The different phase evolution of S1 and S2 signals can be qualitatively described by the proposed model, and detrimental phase history effects are significant at 7 Tesla when not appropriately corrected.

  13. Clinical pulmonary function and industrial respirator wear

    Energy Technology Data Exchange (ETDEWEB)

    Raven, P.B. (Texas College of Osteopathic Medicine, Fort Worth); Moss, R.F.; Page, K.; Garmon, R.; Skaggs, B.

    1981-12-01

    This investigation was the initial step in determining a clinical pulmonary test which could be used to evaluate workers as to their suitability to industrial respirator wear. Sixty subjects, 12 superior, 37 normal, and 11 moderately impaired with respect to lung function tests were evaluated with a battery of clinical pulmonary tests while wearing an industrial respirator. The respirator was a full-face mask (MSA-Ultravue) demand breathing type equipped with an inspiratory resistance of 85mm H/sub 2/O at 85 L/min air flow and an expiratory resistance of 25mm H/sub 2/O at 85 L/min air flow. Comparisons of these tests were made between the three groups of subjects both with and without a respirator. It appears that those lung tests which measure the flow characteristics of the lung especially those that are effort dependant are more susceptible to change as a result of respirator wear. Hence, the respirator affects the person with superior lung function to a greater degree than the moderately impaired person. It was suggested that the clinical test of 15 second maximum voluntary ventilations (MVV./sub 25/) may be the test of choice for determining worker capability in wearing an industrial respirator.

  14. Heterogeneous Community-based mobility model for human opportunistic network

    DEFF Research Database (Denmark)

    Hu, Liang; Dittmann, Lars

    2009-01-01

    Human opportunistic networks can facilitate wireless content dissemination while humans are on the move. In such a network, content is disseminated via nodes relaying and nodes mobility (human mobility). Thus it is essential to understand and model the real human mobility. We present...... a heterogeneous community-based random way-point (HC-RWP) mobility model that captures the four important properties of real human mobility. These properties are based on both intuitive observations of daily human mobility and analysis of empirical mobility traces. By discrete event simulation, we show HC......-RWP captures essential statistic features of wide range of real human mobility traces reported in previous studies....

  15. Approval tests and standards for closed-circuit escape respirators. Final rule.

    Science.gov (United States)

    2012-03-08

    This final rule announces updated requirements that the National Institute for Occupational Safety and Health (NIOSH or Agency), located within the Centers for Disease Control and Prevention (CDC) in the Department of Health and Human Services (HHS or Department), will employ to test and approve closed-circuit respirators used for escaping atmospheres considered to be immediately dangerous to life and health, including such respirators required by the Mine Safety and Health Administration (MSHA) for use in underground coal mines. NIOSH and MSHA jointly review and approve this type of respirator used for mine emergencies under regulations concerning approval of respiratory protective devices. NIOSH also approves these respirators for use in other work environments where escape equipment may be provided to workers, such as on vessels operated by U.S. Navy and Coast Guard personnel. The purpose of these updated requirements is to enable NIOSH and MSHA to more effectively ensure the performance, reliability, and safety of CCERs.

  16. Dengue human infection model performance parameters.

    Science.gov (United States)

    Endy, Timothy P

    2014-06-15

    Dengue is a global health problem and of concern to travelers and deploying military personnel with development and licensure of an effective tetravalent dengue vaccine a public health priority. The dengue viruses (DENVs) are mosquito-borne flaviviruses transmitted by infected Aedes mosquitoes. Illness manifests across a clinical spectrum with severe disease characterized by intravascular volume depletion and hemorrhage. DENV illness results from a complex interaction of viral properties and host immune responses. Dengue vaccine development efforts are challenged by immunologic complexity, lack of an adequate animal model of disease, absence of an immune correlate of protection, and only partially informative immunogenicity assays. A dengue human infection model (DHIM) will be an essential tool in developing potential dengue vaccines or antivirals. The potential performance parameters needed for a DHIM to support vaccine or antiviral candidates are discussed. © The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  17. Evaluating Models of Human Performance: Safety-Critical Systems Applications

    Science.gov (United States)

    Feary, Michael S.

    2012-01-01

    This presentation is part of panel discussion on Evaluating Models of Human Performance. The purpose of this panel is to discuss the increasing use of models in the world today and specifically focus on how to describe and evaluate models of human performance. My presentation will focus on discussions of generating distributions of performance, and the evaluation of different strategies for humans performing tasks with mixed initiative (Human-Automation) systems. I will also discuss issues with how to provide Human Performance modeling data to support decisions on acceptability and tradeoffs in the design of safety critical systems. I will conclude with challenges for the future.

  18. Integrated Human Futures Modeling in Egypt

    Energy Technology Data Exchange (ETDEWEB)

    Passell, Howard D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Aamir, Munaf Syed [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bernard, Michael Lewis [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Beyeler, Walter E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Fellner, Karen Marie [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hayden, Nancy Kay [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jeffers, Robert Fredric [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Keller, Elizabeth James Kistin [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Malczynski, Leonard A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Mitchell, Michael David [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Silver, Emily [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Tidwell, Vincent C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Villa, Daniel [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Vugrin, Eric D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Engelke, Peter [Atlantic Council, Washington, D.C. (United States); Burrow, Mat [Atlantic Council, Washington, D.C. (United States); Keith, Bruce [United States Military Academy, West Point, NY (United States)

    2016-01-01

    The Integrated Human Futures Project provides a set of analytical and quantitative modeling and simulation tools that help explore the links among human social, economic, and ecological conditions, human resilience, conflict, and peace, and allows users to simulate tradeoffs and consequences associated with different future development and mitigation scenarios. In the current study, we integrate five distinct modeling platforms to simulate the potential risk of social unrest in Egypt resulting from the Grand Ethiopian Renaissance Dam (GERD) on the Blue Nile in Ethiopia. The five platforms simulate hydrology, agriculture, economy, human ecology, and human psychology/behavior, and show how impacts derived from development initiatives in one sector (e.g., hydrology) might ripple through to affect other sectors and how development and security concerns may be triggered across the region. This approach evaluates potential consequences, intended and unintended, associated with strategic policy actions that span the development-security nexus at the national, regional, and international levels. Model results are not intended to provide explicit predictions, but rather to provide system-level insight for policy makers into the dynamics among these interacting sectors, and to demonstrate an approach to evaluating short- and long-term policy trade-offs across different policy domains and stakeholders. The GERD project is critical to government-planned development efforts in Ethiopia but is expected to reduce downstream freshwater availability in the Nile Basin, fueling fears of negative social and economic impacts that could threaten stability and security in Egypt. We tested these hypotheses and came to the following preliminary conclusions. First, the GERD will have an important short-term impact on water availability, food production, and hydropower production in Egypt, depending on the short- term reservoir fill rate. Second, the GERD will have a very small impact on

  19. Pellet culture model for human primary osteoblasts.

    Science.gov (United States)

    Jähn, K; Richards, R G; Archer, C W; Stoddart, M J

    2010-09-06

    In vitro monolayer culture of human primary osteoblasts (hOBs) often shows unsatisfactory results for extracellular matrix deposition, maturation and calcification. Nevertheless, monolayer culture is still the method of choice for in vitro differentiation of primary osteoblasts. We believe that the delay in mature ECM production by the monolayer cultured osteoblasts is determined by their state of cell maturation. A functional relationship between the inhibition of osteoblast proliferation and the induction of genes associated with matrix maturation was suggested within a monolayer culture model for rat calvarial osteoblasts. We hypothesize, that a pellet culture model could be utilized to decrease initial proliferation and increase the transformation of osteoblasts into a more mature phenotype. We performed pellet cultures using hOBs and compared their differentiation potential to 2D monolayer cultures. Using the pellet culture model, we were able to generate a population of cuboidal shaped central osteoblastic cells. Increased proliferation, as seen during low-density monolayer culture, was absent in pellet cultures and monolayers seeded at 40,000 cells/cm2. Moreover, the expression pattern of phenotypic markers Runx2, osterix, osteocalcin, col I and E11 mRNA was significantly different depending on whether the cells were cultured in low density monolayer, high density monolayer or pellet culture. We conclude that the transformation of the osteoblast phenotype in vitro to a more mature stage can be achieved more rapidly in 3D culture. Moreover, that dense monolayer leads to the formation of more mature osteoblasts than low-density seeded monolayer, while hOB cells in pellets seem to have transformed even further along the osteoblast phenotype.

  20. Pellet culture model for human primary osteoblasts

    Directory of Open Access Journals (Sweden)

    K Jähn

    2010-09-01

    Full Text Available In vitro monolayer culture of human primary osteoblasts (hOBs often shows unsatisfactory results for extracellular matrix deposition, maturation and calcification. Nevertheless, monolayer culture is still the method of choice for in vitro differentiation of primary osteoblasts. We believe that the delay in mature ECM production by the monolayer cultured osteoblasts is determined by their state of cell maturation. A functional relationship between the inhibition of osteoblast proliferation and the induction of genes associated with matrix maturation was suggested within a monolayer culture model for rat calvarial osteoblasts. We hypothesize, that a pellet culture model could be utilized to decrease initial proliferation and increase the transformation of osteoblasts into a more mature phenotype. We performed pellet cultures using hOBs and compared their differentiation potential to 2D monolayer cultures. Using the pellet culture model, we were able to generate a population of cuboidal shaped central osteoblastic cells. Increased proliferation, as seen during low-density monolayer culture, was absent in pellet cultures and monolayers seeded at 40,000 cells/cm2. Moreover, the expression pattern of phenotypic markers Runx2, osterix, osteocalcin, col I and E11 mRNA was significantly different depending on whether the cells were cultured in low density monolayer, high density monolayer or pellet culture. We conclude that the transformation of the osteoblast phenotype in vitro to a more mature stage can be achieved more rapidly in 3D culture. Moreover, that dense monolayer leads to the formation of more mature osteoblasts than low-density seeded monolayer, while hOB cells in pellets seem to have transformed even further along the osteoblast phenotype.

  1. Light respiration by subtropical seaweeds.

    Science.gov (United States)

    Carvalho, Matheus C; Eyre, Bradley D

    2017-06-01

    Here, we report the first-ever measurements of light CO 2 respiration rate (CRR) by seaweeds. We measured the influence of temperature (15-25°C) and light (irradiance from 60 to 670 μmol · m -2  · s -1 ) on the light CCR of two subtropical seaweed species, and measured the CRR of seven different seaweed species under the same light (150 μmol · m -2  · s -1 ) and temperature (25°C). There was little effect of irradiance on light CRR, but there was an effect of temperature. Across the seven species light CRR was similar to OCR (oxygen consumption rate in the dark), with the exception of a single species. The outlier species was a coralline alga, and the higher light CRR was probably driven by calcification. CRR could be estimated from OCR, as well as carbon photosynthetic rates from oxygen photosynthetic rates, which suggests that previous studies have probably provided good estimations of gross photosynthesis for seaweeds. © 2017 Phycological Society of America.

  2. Dynamic Responses of Root, Mycorrhizal and Soil Heterotrophic Respiration to Temperature Increases in an Arid System of Southeast Spain.

    Science.gov (United States)

    Estruch, C.; Pugnaire, F. I.

    2014-12-01

    Mycorrhizal and heterotrophic respiration may represent up to 80% of total soil respiration in temperate environments; however little is known about arid environments where the dynamics of carbon cycling is less known. To improve models of CO2 efflux to the atmosphere in these environments it is necessary to quantify the contribution of soil components (roots, mycorrhizas and heterotrophic respiration) to soil respiration and their response to temperature increases. We settled up a soil partitioning experiment in December 2013 to address this topic. Using a mesh-collar design we quantified soil respiration of the tree main components (roots, mycorrhiza and heterotrophic respiration) in a Mediterranean arid location dominated by the shrub Rethama sphaerocarpa under two temperature regimes, an increased air temperature using open-top chambers (OTC) and a control. For the firths 6 months of measurements, we recorded a decrease in annual species cover with increased temperature; total soil respiration varied between treatments, being higher in the control treatment while, contrary to our expectations, mycorrhizal and soil heterotrophic respiration did not vary between treatments. When looking at the relative contribution of the different soil components, the treatment enclosing both mycorrhizal and soil heterotrophic respiration represented more than half the total soil respiration. These results show that temperature affects total soil respiration and that, in our case, mycorrhizal and soil heterotrophic community were not major drivers of soil respiration responses to temperature. However, these data correspond to an abnormal dry period and data to be collected during the wet season would help us to better understand the contribution of the different soil components to temperature increases in arid environments.

  3. Vegetation types alter soil respiration and its temperature sensitivity at the field scale in an estuary wetland.

    Science.gov (United States)

    Han, Guangxuan; Xing, Qinghui; Luo, Yiqi; Rafique, Rashad; Yu, Junbao; Mikle, Nate

    2014-01-01

    Vegetation type plays an important role in regulating the temporal and spatial variation of soil respiration. Therefore, vegetation patchiness may cause high uncertainties in the estimates of soil respiration for scaling field measurements to ecosystem level. Few studies provide insights regarding the influence of vegetation types on soil respiration and its temperature sensitivity in an estuary wetland. In order to enhance the understanding of this issue, we focused on the growing season and investigated how the soil respiration and its temperature sensitivity are affected by the different vegetation (Phragmites australis, Suaeda salsa and bare soil) in the Yellow River Estuary. During the growing season, there were significant linear relationships between soil respiration rates and shoot and root biomass, respectively. On the diurnal timescale, daytime soil respiration was more dependent on net photosynthesis. A positive correlation between soil respiration and net photosynthesis at the Phragmites australis site was found. There were exponential correlations between soil respiration and soil temperature, and the fitted Q10 values varied among different vegetation types (1.81, 2.15 and 3.43 for Phragmites australis, Suaeda salsa and bare soil sites, respectively). During the growing season, the mean soil respiration was consistently higher at the Phragmites australis site (1.11 µmol CO2 m(-2) s(-1)), followed by the Suaeda salsa site (0.77 µmol CO2 m(-2) s(-1)) and the bare soil site (0.41 µmol CO2 m(-2) s(-1)). The mean monthly soil respiration was positively correlated with shoot and root biomass, total C, and total N among the three vegetation patches. Our results suggest that vegetation patchiness at a field scale might have a large impact on ecosystem-scale soil respiration. Therefore, it is necessary to consider the differences in vegetation types when using models to evaluate soil respiration in an estuary wetland.

  4. Vegetation types alter soil respiration and its temperature sensitivity at the field scale in an estuary wetland.

    Directory of Open Access Journals (Sweden)

    Guangxuan Han

    Full Text Available Vegetation type plays an important role in regulating the temporal and spatial variation of soil respiration. Therefore, vegetation patchiness may cause high uncertainties in the estimates of soil respiration for scaling field measurements to ecosystem level. Few studies provide insights regarding the influence of vegetation types on soil respiration and its temperature sensitivity in an estuary wetland. In order to enhance the understanding of this issue, we focused on the growing season and investigated how the soil respiration and its temperature sensitivity are affected by the different vegetation (Phragmites australis, Suaeda salsa and bare soil in the Yellow River Estuary. During the growing season, there were significant linear relationships between soil respiration rates and shoot and root biomass, respectively. On the diurnal timescale, daytime soil respiration was more dependent on net photosynthesis. A positive correlation between soil respiration and net photosynthesis at the Phragmites australis site was found. There were exponential correlations between soil respiration and soil temperature, and the fitted Q10 values varied among different vegetation types (1.81, 2.15 and 3.43 for Phragmites australis, Suaeda salsa and bare soil sites, respectively. During the growing season, the mean soil respiration was consistently higher at the Phragmites australis site (1.11 µmol CO2 m(-2 s(-1, followed by the Suaeda salsa site (0.77 µmol CO2 m(-2 s(-1 and the bare soil site (0.41 µmol CO2 m(-2 s(-1. The mean monthly soil respiration was positively correlated with shoot and root biomass, total C, and total N among the three vegetation patches. Our results suggest that vegetation patchiness at a field scale might have a large impact on ecosystem-scale soil respiration. Therefore, it is necessary to consider the differences in vegetation types when using models to evaluate soil respiration in an estuary wetland.

  5. Estimation of lung tissue incompressibility variation throughout respiration for tumor targeting in lung radiotherapy

    Science.gov (United States)

    Shirzadi, Zahra; Samani, Abbas

    2013-03-01

    A novel technique is proposed to characterize lung tissue incompressibility variation during respiration. Lung tissue incompressibility variation stems from significant air content variation in the tissue throughout respiration. Estimating lung tissue incompressibility and its variation is critical for computer assisted tumor motion tracking. Continuous tumor motion during respiration is a major challenge in lung cancer treatment by external beam radiotherapy. If not accounted for, this motion leads to areas of radiation over dosage for the lung normal tissues. Since no effective imaging modality is available for real-time lung tumor tracking, computer based modeling which has the capability for accurate tissue deformation estimation can be a good alternative. Lung tissue deformation estimation can be made using the lung Finite Element (FE) model where its accuracy depends on input tissue biomechanical properties including incompressibility parameter. In this research, an optimization algorithm is proposed to estimate the incompressibility parameter function in terms of respiration cycle time. In this algorithm, the incompressibility parameter and lung pressure values are varied systematically until optimal values, which result in maximum similarity between acquired and simulated 4D CT images of the lung, are achieved for each respiration time point. The simulated images are constructed using a reference image in conjunction with the deformation field obtained from the lung's FE model in each respiration time increment. We demonstrated that utilizing the calculated function along with respiratory system FE modeling leads to accurate tumor targeting, hence potentially improving lung radiotherapy outcome.

  6. Cardiac, Skeletal, and smooth muscle mitochondrial respiration

    DEFF Research Database (Denmark)

    Park, Song-Young; Gifford, Jayson R; Andtbacka, Robert H I

    2014-01-01

    in cardiac, skeletal, and smooth muscle suggest all mitochondria are created equal, the contrasting RCR and non-phosphorylating respiration highlight the existence of intrinsic functional differences between these muscle mitochondria. This likely influences the efficiency of oxidative phosphorylation...

  7. The Contribution of Old Carbon to Respiration from Alaskan Tundra Following Permafrost Thaw

    Science.gov (United States)

    Schuur, E. A.; Vogel, J. G.; Crummer, K. G.; Lee, H.; Sickman, J. O.; Dutta, K.

    2007-12-01

    More than 450 Pg of soil carbon (C) has accumulated in high latitude ecosystems after the retreat of the last major ice sheets. Recent studies suggest that, due to climate warming, these ecosystems may no longer be accumulating C, and in some cases may be losing stored C to the atmosphere. We used radiocarbon measurements of carbon dioxide to detect the age of C respired from tussock tundra near Denali National Park, Alaska. At this tundra site, permafrost has been observed to warm and thaw over the past several decades, causing the ground surface to subside as ice volume in the soil decreased. We established three sites within this area that differed in vegetation and surface topography; both characteristics varied in relation to the degree of permafrost thaw. We made radiocarbon measurements of ecosystem respiration, incubations of soil organic matter, and incubations of above and belowground plant biomass to determine the age and isotopic value of C respired from these sites. Over the study period from 2004 to 2006, ecosystem respiration radiocarbon values averaged from +35‰ to +95‰ in different months across sites. For soil incubations, surface soil radiocarbon was elevated relative both to ecosystem respiration and the current atmospheric radiocarbon value, demonstrating the significant contribution from C fixed over the past years to several decades. The deeper soil, in contrast, had respiration isotope values that averaged below zero, reflecting the significant effect of radioactive decay on the isotope content of deeper soil layers. The plant and soil incubations were combined in a multi- source mixing model to determine probable contributions from these different sources to ecosystem respiration. Deep soil respiration generally averaged between 5-15% of total ecosystem respiration, but reached as high as 40% in some months. When aggregated across the growing season, the two sites undergoing more disturbance from permafrost thaw had on average 2-3 times

  8. Effect of Music on Emotions and Respiration

    OpenAIRE

    NOGUCHI Kengo:筆頭著者; MASAOKA Yuri; SATOH Kanako; KATO Nobumasa; HOMMA Ikuo

    2012-01-01

    In the present study we investigated whether the emotional state induced by music can change respiratory rate (RR), tidal volume (VT), minute ventilation (VE), and end-tidal CO2concentration (ETCO2). In a pioneering study investigating the effect of music on respiration, the music of Stockhausen and Chopin was used. In the present study, we examined the effects of the same musical stimuli used in that study on respiration. Each stimulus (Stockhausen, Chopin, and silence) was delivered for 30 ...

  9. Impact of mixtures of different fresh-cut fruits on respiration and ethylene production rates.

    Science.gov (United States)

    Mahajan, Pramod V; Luca, Alexandru; Edelenbos, Merete

    2014-07-01

    Packaging and storage of fresh-cut fruits and vegetables are a challenging task, since fresh produce continue to respire and senesce after harvest and processing accelerates the physiological processes. The response on respiration and ethylene production rates of fresh produce to changes in O2 and CO2 concentrations and temperature has been extensively studied for whole fruits but literature is limited on processed and mixed fresh-cut fruits. This study aimed to investigate the effects of mixing various proportions of fresh-cut fruits (melon chunks, apple slices, and pineapples cubes) on respiration and ethylene production rates and to develop predictive models for modified atmosphere packaging. The experiment was designed according to a simplex lattice method and respiration and ethylene production rates were measured at 10 °C. Results showed that single component pineapple cubes, apple slices, and melon chunks, in this order, had significant constant coefficients (P = 0.05) and the greatest impact on respiration rate while the interactive binary and tertiary coefficients were insignificant. For ethylene production rates, single component apple slices, melon chunks, and pineapple cubes, and their 3-component mixtures, in this order, had significant constant coefficients (P = 0.05) while binary coefficients were insignificant. Mathematical models were developed and validated; the cubical model was the best to describe the influence of proportion of fruit on respiration and ethylene production rates, however, considering simplicity the linear part of the model is recommended to quantify respiration and ethylene production rates of mixed fresh-cut fruits. This research helps to quantify the ethylene production and respiration rates of multicomponent mixed fresh-cut fruit, which then can be used for packaging design of fresh-cut produce. © 2014 Institute of Food Technologists®

  10. 42 CFR 84.134 - Respirator containers; minimum requirements.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Respirator containers; minimum requirements. 84.134... Respirators § 84.134 Respirator containers; minimum requirements. Supplied-air respirators shall be equipped with a substantial, durable container bearing markings which show the applicant's name, the type and...

  11. 42 CFR 84.197 - Respirator containers; minimum requirements.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Respirator containers; minimum requirements. 84.197... Cartridge Respirators § 84.197 Respirator containers; minimum requirements. Respirators shall be equipped with a substantial, durable container bearing markings which show the applicant's name, the type and...

  12. 42 CFR 84.174 - Respirator containers; minimum requirements.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Respirator containers; minimum requirements. 84.174... Air-Purifying Particulate Respirators § 84.174 Respirator containers; minimum requirements. (a) Except..., durable container bearing markings which show the applicant's name, the type of respirator it contains...

  13. Betaine is a positive regulator of mitochondrial respiration

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Icksoo, E-mail: icksoolee@dankook.ac.kr

    2015-01-09

    Highlights: • Betaine enhances cytochrome c oxidase activity and mitochondrial respiration. • Betaine increases mitochondrial membrane potential and cellular energy levels. • Betaine’s anti-tumorigenic effect might be due to a reversal of the Warburg effect. - Abstract: Betaine protects cells from environmental stress and serves as a methyl donor in several biochemical pathways. It reduces cardiovascular disease risk and protects liver cells from alcoholic liver damage and nonalcoholic steatohepatitis. Its pretreatment can rescue cells exposed to toxins such as rotenone, chloroform, and LiCl. Furthermore, it has been suggested that betaine can suppress cancer cell growth in vivo and in vitro. Mitochondrial electron transport chain (ETC) complexes generate the mitochondrial membrane potential, which is essential to produce cellular energy, ATP. Reduced mitochondrial respiration and energy status have been found in many human pathological conditions including aging, cancer, and neurodegenerative disease. In this study we investigated whether betaine directly targets mitochondria. We show that betaine treatment leads to an upregulation of mitochondrial respiration and cytochrome c oxidase activity in H2.35 cells, the proposed rate limiting enzyme of ETC in vivo. Following treatment, the mitochondrial membrane potential was increased and cellular energy levels were elevated. We propose that the anti-proliferative effects of betaine on cancer cells might be due to enhanced mitochondrial function contributing to a reversal of the Warburg effect.

  14. The physiology of blood loss and shock: New insights from a human laboratory model of hemorrhage.

    Science.gov (United States)

    Schiller, Alicia M; Howard, Jeffrey T; Convertino, Victor A

    2017-04-01

    The ability to quickly diagnose hemorrhagic shock is critical for favorable patient outcomes. Therefore, it is important to understand the time course and involvement of the various physiological mechanisms that are active during volume loss and that have the ability to stave off hemodynamic collapse. This review provides new insights about the physiology that underlies blood loss and shock in humans through the development of a simulated model of hemorrhage using lower body negative pressure. In this review, we present controlled experimental results through utilization of the lower body negative pressure human hemorrhage model that provide novel insights on the integration of physiological mechanisms critical to the compensation for volume loss. We provide data obtained from more than 250 human experiments to classify human subjects into two distinct groups: those who have a high tolerance and can compensate well for reduced central blood volume (e.g. hemorrhage) and those with low tolerance with poor capacity to compensate.We include the conceptual introduction of arterial pressure and cerebral blood flow oscillations, reflex-mediated autonomic and neuroendocrine responses, and respiration that function to protect adequate tissue oxygenation through adjustments in cardiac output and peripheral vascular resistance. Finally, unique time course data are presented that describe mechanistic events associated with the rapid onset of hemodynamic failure (i.e. decompensatory shock). Impact Statement Hemorrhage is the leading cause of death in both civilian and military trauma. The work submitted in this review is important because it advances the understanding of mechanisms that contribute to the total integrated physiological compensations for inadequate tissue oxygenation (i.e. shock) that arise from hemorrhage. Unlike an animal model, we introduce the utilization of lower body negative pressure as a noninvasive model that allows for the study of progressive

  15. Humanized In Vivo Model for Streptococcal Impetigo

    Science.gov (United States)

    Scaramuzzino, Dominick A.; McNiff, Jennifer M.; Bessen, Debra E.

    2000-01-01

    An in vivo model for group A streptococcal (GAS) impetigo was developed, whereby human neonatal foreskin engrafted onto SCID mice was superficially damaged and bacteria were topically applied. Severe infection, indicated by a purulent exudate, could be induced with as few as 1,000 CFU of a virulent strain. Early findings (48 h) showed a loss of stratum corneum and adherence of short chains of gram-positive cocci to the external surface of granular keratinocytes. This was followed by an increasing infiltration of polymorphonuclear leukocytes (neutrophils) of mouse origin, until a thick layer of pus covered an intact epidermis, with massive clumps of cocci accumulated at the outer rim of the pus layer. By 7 days postinoculation, the epidermis was heavily eroded; in some instances, the dermis contained pockets (ulcers) filled with cocci, similar to that observed for ecthyma. Importantly, virulent GAS underwent reproduction, resulting in a net increase in CFU of 20- to 14,000-fold. The majority of emm pattern D strains had a higher gross pathology score than emm pattern A, B, or C (A–C) strains, consistent with epidemiological findings that pattern D strains have a strong tendency to cause impetigo, whereas pattern A–C strains are more likely to cause pharyngitis. PMID:10768985

  16. Modeling human response errors in synthetic flight simulator domain

    Science.gov (United States)

    Ntuen, Celestine A.

    1992-01-01

    This paper presents a control theoretic approach to modeling human response errors (HRE) in the flight simulation domain. The human pilot is modeled as a supervisor of a highly automated system. The synthesis uses the theory of optimal control pilot modeling for integrating the pilot's observation error and the error due to the simulation model (experimental error). Methods for solving the HRE problem are suggested. Experimental verification of the models will be tested in a flight quality handling simulation.

  17. A long term model of circulation. [human body

    Science.gov (United States)

    White, R. J.

    1974-01-01

    A quantitative approach to modeling human physiological function, with a view toward ultimate application to long duration space flight experiments, was undertaken. Data was obtained on the effect of weightlessness on certain aspects of human physiological function during 1-3 month periods. Modifications in the Guyton model are reviewed. Design considerations for bilateral interface models are discussed. Construction of a functioning whole body model was studied, as well as the testing of the model versus available data.

  18. Light-enhanced oxygen respiration in benthic phototrophic communities

    DEFF Research Database (Denmark)

    Epping, EHG; Jørgensen, BB

    1996-01-01

    the day at prevailing light intensities. A 1-dimensional diffusion-reaction model was used to estimate gross photosynthesis and oxygen respiration per volume of sediment, as well as the euphotic depth and the sediment-water interface concentration of oxygen. Areal gross photosynthesis ranged from 9......Two microelectrode studies demonstrate the effect of Light intensity and photosynthesis on areal oxygen respiration in a hypersaline mat at Guerrero Negro, Mexico, and in an intertidal sediment at Texel, The Netherlands. The hypersaline mat was studied in the laboratory at light intensities of 0......, 10, 25, 50, 100, 200, and 500 mu E m(-2) s(-1) using the light-dark shift technique to measure gross photos synthesis rates. Areal gross photosynthesis increased from 0 to 31.3 nmol O-2 cm(-2) min(-1) and areal net photosynthesis increased from -3.9 to 16.7 nmol O-2 cm(-2) min(-1) with increasing...

  19. Case-Based Reasoning for Human Behavior Modeling

    Science.gov (United States)

    2006-02-16

    edition may be used. Case Based Reasoning for Human Behavior Modeling CDRL A002 for Contract N00014-03-C-0178 February 16, 2006 Document...maintaining a useful repository demand that reuse be supported for human behavior modeling even if other model construction aids are also available...et al. (2001). Results of the Common Human Behavior Representation And Interchange System (CHRIS) Workshop. Fall 2001 Simulation Interoperability

  20. Competency Modeling in Extension Education: Integrating an Academic Extension Education Model with an Extension Human Resource Management Model

    Science.gov (United States)

    Scheer, Scott D.; Cochran, Graham R.; Harder, Amy; Place, Nick T.

    2011-01-01

    The purpose of this study was to compare and contrast an academic extension education model with an Extension human resource management model. The academic model of 19 competencies was similar across the 22 competencies of the Extension human resource management model. There were seven unique competencies for the human resource management model.…

  1. Relationship between respiration frequency measurements, mean lung dose and a CT-based NTCP model of the lung in partial lung irradiated minipigs; Beziehungen zwischen Atemfrequenzmessungen, mittlerer Lungendosis und einem CT-basierenden NTCP-Modell der Lunge bei teillungenbestrahlten Minischweinen

    Energy Technology Data Exchange (ETDEWEB)

    Geyer, P.; Appold, S.; Bruechner, K.; Kumpf, R.; Kusche, S.; Baumann, M.; Herrmann, T. [Klinik und Poliklinik fuer Strahlentherapie und Radioonkologie, Technische Univ. Dresden (Germany)

    2004-07-01

    The purpose of the present study was to determine whether there are correlations between respiration physiological findings and representative lung dose values or an NTCP model based on CT lung findings. A total of 38 animals divided into 4 cohorts were irradiated and followed up. Following the end of the irradiation phase the animals' respiration frequency was measured approximately once a week over the duration of a year. Time-matched values obtained from control animals of the same cohort served as a reference base. Lung responses were examined by lung CT and evaluated on the basis of a four-stage score system. [German] Es sollte geprueft werden, ob eine Korrelation zwischen den atemphysiologischen Befunden und repraesentativen Lungendosiswerten oder einem auf den CT-Lungenbefunden basierenden NTCP-Modell existiert. Insgesamt wurden 38 Tiere in 4 Kohorten bestrahlt und im weiteren Verlauf untersucht. Ab Bestrahlungsende wurden fuer die Dauer eines Jahres in etwa woechentlichen Abstaenden die Atemfrequenzen der Versuchstiere gemessen. Dabei dienten die Werte der Kontrolltiere der gleichen Kohorte vom gleichen Messzeitpunkt als Bezug. Mittels CT-Untersuchungen der Lunge wurde die Lungenreaktion nach einem vierstufigen Score-System bewertet. (orig.)

  2. A sample application of nuclear power human resources model

    International Nuclear Information System (INIS)

    Gurgen, A.; Ergun, S.

    2016-01-01

    One of the most important issues for a new comer country initializing the nuclear power plant projects is to have both quantitative and qualitative models for the human resources development. For the quantitative model of human resources development for Turkey, “Nuclear Power Human Resources (NPHR) Model” developed by the Los Alamos National Laboratory was used to determine the number of people that will be required from different professional or occupational fields in the planning of human resources for Akkuyu, Sinop and the third nuclear power plant projects. The number of people required for different professions for the Nuclear Energy Project Implementation Department, the regulatory authority, project companies, construction, nuclear power plants and the academy were calculated. In this study, a sample application of the human resources model is presented. The results of the first tries to calculate the human resources needs of Turkey were obtained. Keywords: Human Resources Development, New Comer Country, NPHR Model

  3. Soil respiration response to climate change in Pacific Northwest prairies is mediated by a regional Mediterranean climate gradient.

    Science.gov (United States)

    Reynolds, Lorien L; Johnson, Bart R; Pfeifer-Meister, Laurel; Bridgham, Scott D

    2015-01-01

    Soil respiration is expected to increase with rising global temperatures but the degree of response may depend on soil moisture and other local factors. Experimental climate change studies from single sites cannot discern whether an observed response is site-dependent or generalizable. To deconvolve site-specific vs. regional climatic controls, we examined soil respiration for 18 months along a 520 km climate gradient in three Pacific Northwest, USA prairies that represents increasingly severe Mediterranean conditions from north to south. At each site we implemented a fully factorial combination of 2.5-3 °C warming and 20% added precipitation intensity. The response of soil respiration to warming was driven primarily by the latitudinal climate gradient and not site-specific factors. Warming increased respiration at all sites during months when soil moisture was not limiting. However, these gains were offset by reductions in respiration during seasonal transitions and summer drought due to lengthened periods of soil moisture limitation. The degree of this offset varied along the north-south climate gradient such that in 2011 warming increased cumulative annual soil respiration 28.6% in the northern site, 13.5% in the central site, and not at all in the southern site. Precipitation also stimulated soil respiration more frequently in the south, consistent with an increased duration of moisture limitation. The best predictors of soil respiration in nonlinear models were the Normalized Difference Vegetation Index (NDVI), antecedent soil moisture, and temperature but these models provided biased results at high and low soil respiration. NDVI was an effective integrator of climate and site differences in plant productivity in terms of their combined effects on soil respiration. Our results suggest that soil moisture limitation can offset the effect of warming on soil respiration, and that greater growing-season moisture limitation would constrain cumulative annual

  4. Molecular Characterization of Bacterial Respiration on Minerals

    Energy Technology Data Exchange (ETDEWEB)

    Blake, Robert C.

    2013-04-26

    anomalous dispersion (MAD) phasing; 4. An acid-stable red cytochrome with a novel absorbance peak at 579 nm was purified from cell-free extracts of L. ferriphilum. Functional studies demonstrated that this cytochrome was an important component of the aerobic iron respiratory chain in this organism; 5. The specific adhesion of At. ferrooxidans to pyrite is mediated by an extracellular protein that was identified as aporusticyanin. The adhesion of At. ferrooxidans to minerals was characterized by high affinity binding that exhibited a high specificity for pyrite over other sulfide minerals. The principal biopolymer involved in this high-affinity adhesion to pyrite was isolated by mineral affinity chromatography and identified as aporusticyanin. The adhesion of purified aporusticyanin to minerals was observed to adhere to different mineral with a pattern of reactivity identical to that observed with the intact bacterium. Further, preincubation of pyrite with excess exogenous aporusticyanin served to inhibit the adherence of intact cells to the surface of the mineral, indicating that the protein and the cells adhered to the pyrite in a mutually exclusive manner. Taken together, these observations support a model where aporusticyanin located on the surface of the bacterial cell acts as a mineral-specific receptor for the initial adherence of At. ferrooxidans to solid pyrite; 6. The specific adhesion of L. ferriphilum to pyrite was mediated by a different acid-stable extracellular protein than aporusticyanin; and 7. A prototype integrating cavity absorption meter (ICAM) was assembled to determine whether this novel spectrophotometer could be used to study cellular respiration in situ.

  5. Gastrocnemius mitochondrial respiration: are there any differences between men and women?

    Science.gov (United States)

    Thompson, Jonathan R; Swanson, Stanley A; Casale, George P; Johanning, Jason M; Papoutsi, Evlampia; Koutakis, Panagiotis; Miserlis, Dimitrios; Zhu, Zhen; Pipinos, Iraklis I

    2013-11-01

    Work on human and mouse skeletal muscle by our group and others has demonstrated that aging and age-related degenerative diseases are associated with mitochondrial dysfunction, which may be more prevalent in males. There have been, however, no studies that specifically examine the influence of male or female sex on human skeletal muscle mitochondrial respiration. The purpose of this study was to compare mitochondrial respiration in the gastrocnemius of adult men and women. Gastrocnemius muscle was obtained from male (n = 19) and female (n = 11) human subjects with healthy lower-extremity musculoskeletal and arterial systems and normal ambulatory function. All patients were undergoing operations for the treatment of varicose veins in their legs. Mitochondrial respiration was determined with a Clark electrode in an oxygraph cell containing saponin-skinned muscle bundles. Complex I-, II-, III-, and IV-dependent respiration was measured individually and normalized to muscle weight, total protein content, and citrate synthase (CS, index of mitochondrial content). Male and female patients had no evidence of musculoskeletal or arterial disease and did not differ with regard to age, race, body mass index, or other clinical characteristics. Complex I-, II-, III-, and IV-dependent respiration normalized to muscle weight, total protein content, and CS did not statistically differ for males compared with females. Our study evaluates, for the first time, gastrocnemius mitochondrial respiration of adult men and women who have healthy musculoskeletal and arterial systems and normal ambulatory function. Our data demonstrate there are no differences in the respiration of gastrocnemius mitochondria between men and women. Copyright © 2013 Elsevier Inc. All rights reserved.

  6. Significance of cold-season respiration and photosynthesis in a subarctic heath ecosystem in Northern Sweden

    DEFF Research Database (Denmark)

    Larsen, Klaus Steenberg; Ibrom, A.; Jonasson, S.

    2007-01-01

    While substantial cold-season respiration has been documented in most arctic and alpine ecosystems in recent years, the significance of cold-season photosynthesis in these biomes is still believed to be small. In a mesic, subartic heath during both the cold and warm season, we measured in situ...... ecosystem respiration and photosynthesis with a chamber technique at ambient conditions and at artificially, increased frequency of freeze-thaw (FT) cycles during fall and spring. We fitted the measured ecosystem exchange rates to respiration and photosynthesis models with R-2-values ranging from 0.81 to 0.......85. As expected, estimated cold-season (October, November, April and May) respiration was significant and accounted for at least 22% of the annual respiratory CO2 flux. More surprisingly, estimated photosynthesis during this period accounted for up to 19% of the annual gross CO2 uptake, suggesting that cold...

  7. Soil respiration and organic carbon dynamics with grassland conversions to woodlands in temperate china.

    Directory of Open Access Journals (Sweden)

    Wei Wang

    Full Text Available Soils are the largest terrestrial carbon store and soil respiration is the second-largest flux in ecosystem carbon cycling. Across China's temperate region, climatic changes and human activities have frequently caused the transformation of grasslands to woodlands. However, the effect of this transition on soil respiration and soil organic carbon (SOC dynamics remains uncertain in this area. In this study, we measured in situ soil respiration and SOC storage over a two-year period (Jan. 2007-Dec. 2008 from five characteristic vegetation types in a forest-steppe ecotone of temperate China, including grassland (GR, shrubland (SH, as well as in evergreen coniferous (EC, deciduous coniferous (DC and deciduous broadleaved forest (DB, to evaluate the changes of soil respiration and SOC storage with grassland conversions to diverse types of woodlands. Annual soil respiration increased by 3%, 6%, 14%, and 22% after the conversion from GR to EC, SH, DC, and DB, respectively. The variation in soil respiration among different vegetation types could be well explained by SOC and soil total nitrogen content. Despite higher soil respiration in woodlands, SOC storage and residence time increased in the upper 20 cm of soil. Our results suggest that the differences in soil environmental conditions, especially soil substrate availability, influenced the level of annual soil respiration produced by different vegetation types. Moreover, shifts from grassland to woody plant dominance resulted in increased SOC storage. Given the widespread increase in woody plant abundance caused by climate change and large-scale afforestation programs, the soils are expected to accumulate and store increased amounts of organic carbon in temperate areas of China.

  8. Cardiac, skeletal, and smooth muscle mitochondrial respiration: are all mitochondria created equal?

    Science.gov (United States)

    Park, Song-Young; Gifford, Jayson R; Andtbacka, Robert H I; Trinity, Joel D; Hyngstrom, John R; Garten, Ryan S; Diakos, Nikolaos A; Ives, Stephen J; Dela, Flemming; Larsen, Steen; Drakos, Stavros; Richardson, Russell S

    2014-08-01

    Unlike cardiac and skeletal muscle, little is known about vascular smooth muscle mitochondrial respiration. Therefore, the present study examined mitochondrial respiratory rates in smooth muscle of healthy human feed arteries and compared with that of healthy cardiac and skeletal muscles. Cardiac, skeletal, and smooth muscles were harvested from a total of 22 subjects (53 ± 6 yr), and mitochondrial respiration was assessed in permeabilized fibers. Complex I + II, state 3 respiration, an index of oxidative phosphorylation capacity, fell progressively from cardiac to skeletal to smooth muscles (54 ± 1, 39 ± 4, and 15 ± 1 pmol·s(-1)·mg(-1), P muscles (222 ± 13, 115 ± 2, and 48 ± 2 μmol·g(-1)·min(-1), P respiration rates were normalized by CS (respiration per mitochondrial content), oxidative phosphorylation capacity was no longer different between the three muscle types. Interestingly, complex I state 2 normalized for CS activity, an index of nonphosphorylating respiration per mitochondrial content, increased progressively from cardiac to skeletal to smooth muscles, such that the respiratory control ratio, state 3/state 2 respiration, fell progressively from cardiac to skeletal to smooth muscles (5.3 ± 0.7, 3.2 ± 0.4, and 1.6 ± 0.3 pmol·s(-1)·mg(-1), P muscles suggest all mitochondria are created equal, the contrasting respiratory control ratio and nonphosphorylating respiration highlight the existence of intrinsic functional differences between these muscle mitochondria. This likely influences the efficiency of oxidative phosphorylation and could potentially alter ROS production.

  9. Human tumor infiltrating lymphocytes cooperatively regulate prostate tumor growth in a humanized mouse model

    OpenAIRE

    Roth, Michael D; Harui, Airi

    2015-01-01

    BACKGROUND: The complex interactions that occur between human tumors, tumor infiltrating lymphocytes (TIL) and the systemic immune system are likely to define critical factors in the host response to cancer. While conventional animal models have identified an array of potential anti-tumor therapies, mouse models often fail to translate into effective human treatments. Our goal is to establish a humanized tumor model as a more effective pre-clinical platform for understanding and manipulating ...

  10. Assessment of half-mask elastomeric respirator and powered air-purifying respirator reprocessing for an influenza pandemic.

    Science.gov (United States)

    Lawrence, Caryn; Harnish, Delbert A; Sandoval-Powers, Megan; Mills, Devin; Bergman, Michael; Heimbuch, Brian K

    2017-12-01

    Health care facilities are considering the use of reusable respiratory protective devices (RPDs) to mitigate a potential N95 filtering facepiece respirator shortage caused by an influenza pandemic. US regulators are also considering stockpiling reusable RPDs for pandemic preparedness, but limited data exist on the effectiveness of cleaning and disinfection of these devices. This study defines reprocessing protocols and evaluates their effectiveness against a pandemic influenza strain in a laboratory setting. Five half-mask elastomeric respirator models and 3 powered air-purifying respirator models were contaminated with influenza virus and artificial skin oil on multiple surfaces. RPDs were then manually treated with 1 of 2 methods: cleaned or cleaned and disinfected. Presence of viable influenza was determined via swab sampling and a median tissue culture infectious dose assay. Across 41 RPD surfaces, a mean log reduction in viable influenza of 4.54 ± 0.97 log 10 median tissue culture infectious dose was achieved for all treated surfaces, which included both cleaned and cleaned and disinfected surfaces. The methods defined as part of this study are effective for eliminating viable influenza in the presence of artificial skin oil on most of the RPD surfaces tested. Material type and RPD design should be considered when implementing RPD reprocessing protocols. Copyright © 2017 Association for Professionals in Infection Control and Epidemiology, Inc. All rights reserved.

  11. Human Systems Integration (HSI) Tradeoff Model

    Science.gov (United States)

    2014-03-01

    distribution is unlimited. Release # 88ABW-2014- 1475, dated 7 Apr 2014. on grammatical and software errors and the recommendation to add a screen (Figure 17...SIGNATURE// MATTHEW T. TARANTO, Major, USAF Chief, Human Systems Analysis Division Human Systems Integration Directorate...enhancing the understanding of HSI tradeoffs. At the direction of 711 HPW/HP, the Survivability/ Vulnerability Information Analysis Center (SURVIAC

  12. A model of the human retina

    DEFF Research Database (Denmark)

    Jørgensen, John Leif

    1998-01-01

    Traditionally, the human eye is perceived as being "just" a camera, that renders an accurate, although limited, image for processing in the brain. This interpretation probably stems from the apparent similarity between a video- or photo-camera and a human eye with respect to the lens, the iris...

  13. Modelling Human Exposure to Chemicals in Food

    NARCIS (Netherlands)

    Slob W

    1993-01-01

    Exposure to foodborne chemicals is often estimated using the average consumption pattern in the human population. To protect the human population instead of the average individual, however, interindividual variability in consumption behaviour must be taken into account. This report shows how food

  14. Human-water interface in hydrological modelling

    NARCIS (Netherlands)

    Wada, Yoshihide; Bierkens, Marc F.P.; Roo, de Ad; Dirmeyer, Paul A.; Famiglietti, James S.; Hanasaki, Naota; Konar, Megan; Liu, Junguo; Schmied, Hannes Möller; Oki, Taikan; Pokhrel, Yadu; Sivapalan, Murugesu; Troy, Tara J.; Dijk, Van Albert I.J.M.; Emmerik, Van Tim; Huijgevoort, Van Marjolein H.J.; Lanen, van Henny A.J.; Vörösmarty, Charles J.; Wanders, Niko; Wheater, Howard

    2017-01-01

    Over recent decades, the global population has been rapidly increasing and human activities have altered terrestrial water fluxes to an unprecedented extent. The phenomenal growth of the human footprint has significantly modified hydrological processes in various ways (e.g. irrigation, artificial

  15. Reconstruction of human mammary tissues in a mouse model.

    Science.gov (United States)

    Proia, David A; Kuperwasser, Charlotte

    2006-01-01

    Establishing a model system that more accurately recapitulates both normal and neoplastic breast epithelial development in rodents is central to studying human breast carcinogenesis. However, the inability of human breast epithelial cells to colonize mouse mammary fat pads is problematic. Considering that the human breast is a more fibrous tissue than is the adipose-rich stroma of the murine mammary gland, our group sought to bypass the effects of the rodent microenvironment through incorporation of human stromal fibroblasts. We have been successful in reproducibly recreating functionally normal breast tissues from reduction mammoplasty tissues, in what we term the human-in-mouse (HIM) model. Here we describe our relatively simple and inexpensive techniques for generating this orthotopic xenograft model. Whether the model is to be applied for understanding normal human breast development or tumorigenesis, investigators with minimal animal surgery skills, basic cell culture techniques and access to human breast tissue will be able to generate humanized mouse glands within 3 months. Clearing the mouse of its endogenous epithelium with subsequent stromal humanization takes 1 month. The subsequent implantation of co-mixed human epithelial cells and stromal cells occurs 2 weeks after humanization, so investigators should expect to observe the desired outgrowths 2 months afterward. As a whole, this model system has the potential to improve the understanding of crosstalk between tissue stroma and the epithelium as well as factors involved in breast stem cell biology tumor initiation and progression.

  16. Pharmacological migraine provocation: a human model of migraine

    DEFF Research Database (Denmark)

    Ashina, Messoud; Hansen, Jakob Møller

    2010-01-01

    . If a naturally occurring substance can provoke migraine in human patients, then it is likely, although not certain, that blocking its effect will be effective in the treatment of acute migraine attacks. To this end, a human in vivo model of experimental headache and migraine in humans has been developed...

  17. Effect of rotenone on gill-respiring and plastron-respiring insects ...

    African Journals Online (AJOL)

    Rotenone, a commonly-used piscicide, interferes with the cellular respiration of aquatic vertebrates and invertebrates by preventing the uptake of oxygen. While dose-response relationships have been developed for fish, there are limited comparative data available on aquatic insects that respire either with tracheal gills or ...

  18. Development of a rhesus monkey lung geometry model and application to particle deposition in comparison to humans

    Science.gov (United States)

    Asgharian, Bahman; Price, Owen; McClellan, Gene; Corley, Rick; Einstein, Daniel R.; Jacob, Richard E.; Harkema, Jack; Carey, Stephan A.; Schelegle, Edward; Hyde, Dallas; Kimbell, Julia S.; Miller, Frederick J.

    2016-01-01

    The exposure-dose-response characterization of an inhalation hazard established in an animal species needs to be translated to an equivalent characterization in humans relative to comparable doses or exposure scenarios. Here, the first geometry model of the conducting airways for rhesus monkeys is developed based upon CT images of the conducting airways of a 6-month-old male, rhesus monkey. An algorithm was developed for adding the alveolar region airways using published rhesus morphometric data. The resultant lung geometry model can be used in mechanistic particle or gaseous dosimetry models. Such dosimetry models require estimates of the upper respiratory tract volume of the animal and the functional residual capacity, as well as of the tidal volume and breathing frequency of the animal. The relationship of these variables to rhesus monkeys of differing body weights was established by synthesizing and modeling published data as well as modeling pulmonary function measurements on 121 rhesus control animals. Deposition patterns of particles up to 10 μm in size were examined for endotracheal and and up to 5 μm for spontaneous breathing in infant and young adult monkeys and compared to those for humans. Deposition fraction of respirable size particles was found to be higher in the conducting airways of infant and young adult rhesus monkeys compared to humans. Due to the filtering effect of the conducting airways, pulmonary deposition in rhesus monkeys was lower than that in humans. Future research areas are identified that would either allow replacing assumptions or improving the newly developed lung model. PMID:23121298

  19. A New Compendium of Soil Respiration Data for Africa

    Directory of Open Access Journals (Sweden)

    Terence Epule Epule

    2015-04-01

    Full Text Available The objective of this paper is to present to the scientific community a new dataset derived from existing literature on soil respiration in Africa. The data has thus been obtained by searching for records in peer review papers and grey literature. The main search engines used are: Scientific Citation Index (SCI database, ISI Science web and Google scholar. This data description paper has greatly advanced the number of data points on soil respiration in Africa from 4 in 2010 to 62 in 2014. The new data points are culled from 47 peer review publications and grey literature reports. The data lends its self to a lot of possible analytical methods such as correlation analysis, multiple linear regressions, artificial neural network analysis and process base modeling. The overall conclusion that can be drawn here is that this paper has greatly advanced the availability of soil respiration data in Africa by presenting all the available records that before now were only reported in different studies.

  20. Respiration of Chemodenervated Goats in Acute Metabolic Acidosis,

    Science.gov (United States)

    1983-08-02

    metabolic ) alkalosis . Furthermore, the ventilatory responses to increase in PaCO2 produced by CO2 inhalation are shifted to lower values of PaCO2 in...the presence of metabolic acidosis, and to higher PaCO2 vaiues in metabolic alkalosis (Fencl et al. [1966]). The roles played by the carotid bodies (CB...and J.A. Broch (1969). Respiration and cerebral blood flow in metabolic acidosis and alkalosis in humans. J. Appl. Physiol. 27: 67-76. Gabel, R.A

  1. [Characteristics of Soil Respiration along Eroded Sloping Land with Different SOC Background on the Hilly Loess Plateau].

    Science.gov (United States)

    Chen, Gai; Xu, Ming-xiang; Zhang, Ya-feng; Wang, Chao-hua; Fan, Hui-min; Wang, Shan-shan

    2015-09-01

    This study aimed to characterize soil respiration along eroded sloping land at erosion and deposition area under different soil organic carbon(SOC) levels, and linked the relationship between soil respiration and soil temperature, soil moisture, SOC and slope position. Experiments were carried out in the plots of S type slopes include five different soil organic carbon levels in the Loess Hilly Region. The S type slopes were divided into control area at the top of the slope, erosion area at the middle of the slope and deposition area at the toe of the slope. We found that soil temperature had a greater impact on soil respiration in the deposition area, whereas soil moisture had a greater impact on soil respiration in the erosion area compared among control area, erosion area and deposition area. In addition, SOC was the most important factor affecting soil respiration, which can explain soil respiration variation 54. 72%, followed by soil moisture, slope position and soil temperature, which explain soil respiration variation 18. 86% , 16. 13% and 10. 29%, respectively. Soil respiration response to erosion showed obvious on-site and off-site effects along the eroded sloping land. Soil respiration in the erosion area was reduced by 21. 14% compared with control area, and soil respiration in the deposition area was increased by 21. 93% compared with control area. Erosion effect on source and sink of carbon emission was correlated with SOC content of the eroded sloping land. When SOC content was higher than 6. 82 g.kg-1, the slope. erosion tended to be a carbon sequestration process, and when SOC content was lower than 3.03 g.kg-1, the slope erosion tended to be a process of the carbon emission source. The model could reflect the relationship between soil respiration and independent variables of soil organic carbon content, soil temperature and moisture.

  2. Pharmacological migraine provocation: a human model of migraine

    DEFF Research Database (Denmark)

    Ashina, Messoud; Hansen, Jakob Møller

    2010-01-01

    for migraine mechanisms. So far, however, animal models cannot predict the efficacy of new therapies for migraine. Because migraine attacks are fully reversible and can be aborted by therapy, the headache- or migraine-provoking property of naturally occurring signaling molecules can be tested in a human model....... If a naturally occurring substance can provoke migraine in human patients, then it is likely, although not certain, that blocking its effect will be effective in the treatment of acute migraine attacks. To this end, a human in vivo model of experimental headache and migraine in humans has been developed...

  3. Numerical Modeling of Electromagnetic Field Effects on the Human Body

    Directory of Open Access Journals (Sweden)

    Zuzana Psenakova

    2006-01-01

    Full Text Available Interactions of electromagnetic field (EMF with environment and with tissue of human beings are still under discussion and many research teams are investigating it. The human simulation models are used for biomedical research in a lot of areas, where it is advantage to replace real human body (tissue by the numerical model. Biological effects of EMF are one of the areas, where numerical models are used with many advantages. On the other side, this research is very specific and it is always quite hard to simulate realistic human tissue. This paper deals with different possibilities of numerical modelling of electromagnetic field effects on the human body (especially calculation of the specific absorption rate (SAR distribution in human body and thermal effect.

  4. Minimizing Human Risk: Human Performance Models in the Space Human Factors and Habitability and Behavioral Health and Performance Elements

    Science.gov (United States)

    Gore, Brian F.

    2016-01-01

    Human space exploration has never been more exciting than it is today. Human presence to outer worlds is becoming a reality as humans are leveraging much of our prior knowledge to the new mission of going to Mars. Exploring the solar system at greater distances from Earth than ever before will possess some unique challenges, which can be overcome thanks to the advances in modeling and simulation technologies. The National Aeronautics and Space Administration (NASA) is at the forefront of exploring our solar system. NASA's Human Research Program (HRP) focuses on discovering the best methods and technologies that support safe and productive human space travel in the extreme and harsh space environment. HRP uses various methods and approaches to answer questions about the impact of long duration missions on the human in space including: gravity's impact on the human body, isolation and confinement on the human, hostile environments impact on the human, space radiation, and how the distance is likely to impact the human. Predictive models are included in the HRP research portfolio as these models provide valuable insights into human-system operations. This paper will provide an overview of NASA's HRP and will present a number of projects that have used modeling and simulation to provide insights into human-system issues (e.g. automation, habitat design, schedules) in anticipation of space exploration.

  5. Animal models for human genetic diseases | Sharif | African Journal ...

    African Journals Online (AJOL)

    The study of human genetic diseases can be greatly aided by animal models because of their similarity to humans in terms of genetics. In addition to understand diverse aspects of basic biology, model organisms are extensively used in applied research in agriculture, industry, and also in medicine, where they are used to ...

  6. General Computational Model for Human Musculoskeletal System of Spine

    Directory of Open Access Journals (Sweden)

    Kyungsoo Kim

    2012-01-01

    Full Text Available A general computational model of the human lumbar spine and trunk muscles including optimization formulations was provided. For a given condition, the trunk muscle forces could be predicted considering the human physiology including the follower load concept. The feasibility of the solution could be indirectly validated by comparing the compressive force, the shear force, and the joint moment. The presented general computational model and optimization technology can be fundamental tools to understand the control principle of human trunk muscles.

  7. Specific and General Human Capital in an Endogenous Growth Model

    OpenAIRE

    Evangelia Vourvachaki; Vahagn Jerbashian; : Sergey Slobodyan

    2014-01-01

    In this article, we define specific (general) human capital in terms of the occupations whose use is spread in a limited (wide) set of industries. We analyze the growth impact of an economy's composition of specific and general human capital, in a model where education and research and development are costly and complementary activities. The model suggests that a declining share of specific human capital, as observed in the Czech Republic, can be associated with a lower rate of long-term grow...

  8. Human-water interface in hydrological modelling

    OpenAIRE

    Wada, Yoshihide; Bierkens, Marc F.P.; Roo, de, Ad; Dirmeyer, Paul A.; Famiglietti, James S.; Hanasaki, Naota; Konar, Megan; Liu, Junguo; Schmied, Hannes Möller; Oki, Taikan; Pokhrel, Yadu; Sivapalan, Murugesu; Troy, Tara J.; Dijk, Van, Albert I.J.M.; Emmerik, Van, Tim

    2017-01-01

    Over recent decades, the global population has been rapidly increasing and human activities have altered terrestrial water fluxes to an unprecedented extent. The phenomenal growth of the human footprint has significantly modified hydrological processes in various ways (e.g. irrigation, artificial dams, and water diversion) and at various scales (from a watershed to the globe). During the early 1990s, awareness of the potential for increased water scarcity led to the first detailed global wate...

  9. Humanized mouse model for assessing the human immune response to xenogeneic and allogeneic decellularized biomaterials.

    Science.gov (United States)

    Wang, Raymond M; Johnson, Todd D; He, Jingjin; Rong, Zhili; Wong, Michelle; Nigam, Vishal; Behfar, Atta; Xu, Yang; Christman, Karen L

    2017-06-01

    Current assessment of biomaterial biocompatibility is typically implemented in wild type rodent models. Unfortunately, different characteristics of the immune systems in rodents versus humans limit the capability of these models to mimic the human immune response to naturally derived biomaterials. Here we investigated the utility of humanized mice as an improved model for testing naturally derived biomaterials. Two injectable hydrogels derived from decellularized porcine or human cadaveric myocardium were compared. Three days and one week after subcutaneous injection, the hydrogels were analyzed for early and mid-phase immune responses, respectively. Immune cells in the humanized mouse model, particularly T-helper cells, responded distinctly between the xenogeneic and allogeneic biomaterials. The allogeneic extracellular matrix derived hydrogels elicited significantly reduced total, human specific, and CD4 + T-helper cell infiltration in humanized mice compared to xenogeneic extracellular matrix hydrogels, which was not recapitulated in wild type mice. T-helper cells, in response to the allogeneic hydrogel material, were also less polarized towards a pro-remodeling Th2 phenotype compared to xenogeneic extracellular matrix hydrogels in humanized mice. In both models, both biomaterials induced the infiltration of macrophages polarized towards a M2 phenotype and T-helper cells polarized towards a Th2 phenotype. In conclusion, these studies showed the importance of testing naturally derived biomaterials in immune competent animals and the potential of utilizing this humanized mouse model for further studying human immune cell responses to biomaterials in an in vivo environment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Redefinition and global estimation of basal ecosystem respiration rate

    DEFF Research Database (Denmark)

    Yuan, Wenping; Luo, Yiqi; Li, Xianglan

    2011-01-01

    use a global constant BR largely due to the lack of a functional description for BR. In this study, we redefined BR to be ecosystem respiration rate at the mean annual temperature. To test the validity of this concept, we conducted a synthesis analysis using 276 site-years of eddy covariance data....... These results confirm that ER at the mean annual temperature can be considered as BR in empirical models. A strong correlation was found between the mean annual ER and mean annual gross primary production (GPP). Consequently, GPP, which is typically more accurately modeled, can be used to estimate BR. A light...

  11. Mitochondrial respiration in peripheral blood mononuclear cells correlates with depressive subsymptoms and severity of major depression.

    Science.gov (United States)

    Karabatsiakis, A; Böck, C; Salinas-Manrique, J; Kolassa, S; Calzia, E; Dietrich, D E; Kolassa, I-T

    2014-06-10

    Mitochondrial dysfunction might have a central role in the pathophysiology of depression. Phenotypically, depression is characterized by lack of energy, concentration problems and fatigue. These symptoms might be partially explained by reduced availability of adenosine triphosphate (ATP) as a consequence of impaired mitochondrial functioning. This study investigated mitochondrial respiration in peripheral blood mononuclear cells (PBMCs), an established model to investigate the pathophysiology of depression. Mitochondrial respiration was assessed in intact PBMCs in 22 individuals with a diagnosis of major depression (MD) compared with 22 healthy age-matched controls using high-resolution respirometry. Individuals with MD showed significantly impaired mitochondrial functioning: routine and uncoupled respiration as well as spare respiratory capacity, coupling efficiency and ATP turnover-related respiration were significantly lower in the MD compared with the control group. Furthermore, mitochondrial respiration was significantly negatively correlated with the severity of depressive symptoms, in particular, with loss of energy, difficulties concentrating and fatigue. The results suggest that mitochondrial dysfunction contributes to the biomolecular pathophysiology of depressive symptoms. The decreased immune capability observed in MD leading to a higher risk of comorbidities could be attributable to impaired energy supply due to mitochondrial dysfunction. Thus mitochondrial respiration in PBMCs and its functional consequences might be an interesting target for new therapeutical approaches in the treatment of MD and immune-related comorbidities.

  12. Nonlinear responses of soil respiration to precipitation changes in a semiarid temperate steppe.

    Science.gov (United States)

    Miao, Yuan; Han, Hongyan; Du, Yue; Zhang, Qian; Jiang, Lin; Hui, Dafeng; Wan, Shiqiang

    2017-03-31

    Extreme precipitation events are predicted to occur more frequently and will have significant influences on terrestrial ecosystem carbon (C) cycling in the future. However, response patterns of soil respiration to precipitation changes remain uncertain in terrestrial ecosystems. A field experiment with seven precipitation treatments (i.e. from -60% to +60% of ambient precipitation to form a drought to wet precipitation gradient) was conducted over three growing seasons (2010-2012) in a semiarid temperate steppe of Northern China. Results showed a nonlinear response pattern of soil respiration along the experimental precipitation gradient, with soil respiration suppressed by decreased precipitation and enhanced by increased precipitation. Over the three growing seasons, soil respiration was reduced more under the three drought treatments (by 45.8, 32.8, and 15.9% under the -60, -40, and -20% treatments, respectively) than stimulated under the three wet treatments (by 8.9, 14.3, and 18.5% under the +20, +40, and +60% treatments, respectively). Our results indicate that soil respiration was more sensitive to decreased than increased precipitation treatments. The nonlinear and asymmetric responses of soil respiration to precipitation changes should be built into ecosystem models to project ecosystem C cycling associated with climate change.

  13. A numerical model for blast injury of human thorax based on digitized visible human.

    Science.gov (United States)

    Li, Xiao-Fang; Kuang, Jiang-Ming; Nie, Si-Bing; Xu, Jing; Zhu, Jin; Liu, Yi-He

    2017-12-04

    Knowledge of the pressure distribution around human thorax in blast help to understand the injury mechanisms and their assessment. To investigate the transmission mechanism of the pressure on human thorax in blast, a three dimension surface model of human thorax was constructed in this work. To increase the precious of this model, tetrahedron element division method was applied to transfer the rough 3D surface model to hexahedral elements model. Using this model, the high pressure duration was computationally solved using numerical simulation of the hexahedral elements. Simulation results showed that the apex of lungs was subjected to the largest stress in a blast. In order to verify this result, an animal experiment was performed on a dog. The animal experimental results was shown to have a same variation tendency with the calculation results based on our numerical model of human thorax, which made this model reliable for the blast injury research.

  14. Applications and Limitations of Mouse Models for Understanding Human Atherosclerosis

    Science.gov (United States)

    von Scheidt, Moritz; Zhao, Yuqi; Kurt, Zeyneb; Pan, Calvin; Zeng, Lingyao; Yang, Xia; Schunkert, Heribert; Lusis, Aldons J.

    2017-01-01

    Most of the biological understanding of mechanisms underlying coronary artery disease (CAD) derives from studies of mouse models. The identification of multiple CAD loci and strong candidate genes in large human genome-wide association studies (GWAS) presented an opportunity to examine the relevance of mouse models for the human disease. We comprehensively reviewed the mouse literature, including 827 literature-derived genes, and compared it to human data. First, we observed striking concordance of risk factors for atherosclerosis in mice and humans. Second, there was highly significant overlap of mouse genes with human genes identified by GWAS. In particular, of the 46 genes with strong association signals in CAD-GWAS that were studied in mouse models all but one exhibited consistent effects on atherosclerosis-related phenotypes. Third, we compared 178 CAD-associated pathways derived from human GWAS with 263 from mouse studies and observed that over 50% were consistent between both species. PMID:27916529

  15. Zebrafish heart as a model for human cardiac electrophysiology.

    Science.gov (United States)

    Vornanen, Matti; Hassinen, Minna

    2016-01-01

    The zebrafish (Danio rerio) has become a popular model for human cardiac diseases and pharmacology including cardiac arrhythmias and its electrophysiological basis. Notably, the phenotype of zebrafish cardiac action potential is similar to the human cardiac action potential in that both have a long plateau phase. Also the major inward and outward current systems are qualitatively similar in zebrafish and human hearts. However, there are also significant differences in ionic current composition between human and zebrafish hearts, and the molecular basis and pharmacological properties of human and zebrafish cardiac ionic currents differ in several ways. Cardiac ionic currents may be produced by non-orthologous genes in zebrafish and humans, and paralogous gene products of some ion channels are expressed in the zebrafish heart. More research on molecular basis of cardiac ion channels, and regulation and drug sensitivity of the cardiac ionic currents are needed to enable rational use of the zebrafish heart as an electrophysiological model for the human heart.

  16. Mouse models for understanding human developmental anomalies

    International Nuclear Information System (INIS)

    Generoso, W.M.

    1989-01-01

    The mouse experimental system presents an opportunity for studying the nature of the underlying mutagenic damage and the molecular pathogenesis of this class of anomalies by virtue of the accessibility of the zygote and its descendant blastomeres. Such studies could contribute to the understanding of the etiology of certain sporadic but common human malformations. The vulnerability of the zygotes to mutagens as demonstrated in the studies described in this report should be a major consideration in chemical safety evaluation. It raises questions regarding the danger to human zygotes when the mother is exposed to drugs and environmental chemicals

  17. Mouse models for understanding human developmental anomalies

    Energy Technology Data Exchange (ETDEWEB)

    Generoso, W.M.

    1989-01-01

    The mouse experimental system presents an opportunity for studying the nature of the underlying mutagenic damage and the molecular pathogenesis of this class of anomalies by virtue of the accessibility of the zygote and its descendant blastomeres. Such studies could contribute to the understanding of the etiology of certain sporadic but common human malformations. The vulnerability of the zygotes to mutagens as demonstrated in the studies described in this report should be a major consideration in chemical safety evaluation. It raises questions regarding the danger to human zygotes when the mother is exposed to drugs and environmental chemicals.

  18. [Attempt at computer modeling of evolution of human society].

    Science.gov (United States)

    Levchenko, V F; Menshutkin, V V

    2009-01-01

    A model of evolution of human society and biosphere, which is based on the concepts of V. I. Vernadskii about noosphere and of L. N. Gumilev about ethnogenesis is developed and studied. The mathematical apparatus of the model is composition of finite stochastic automata. By using this model, a possibility of the global ecological crisis is demonstrated in the case of preservation of the current tendencies of interaction of the biosphere and the human civilization.

  19. Human Cancer Models Initiative | Office of Cancer Genomics

    Science.gov (United States)

    The Human Cancer Models Initiative (HCMI) is an international consortium that is generating novel human tumor-derived culture models, which are annotated with genomic and clinical data. In an effort to advance cancer research and more fully understand how in vitro findings are related to clinical biology, HCMI-developed models and related data will be available as a community resource for cancer and other research.

  20. 42 CFR 84.162 - Man test for gases and vapors; Type C respirators, continuous-flow class and Type CE supplied-air...

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Man test for gases and vapors; Type C respirators, continuous-flow class and Type CE supplied-air respirators; test requirements. 84.162 Section 84.162 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL...

  1. Synthetic vision and memory model for virtual human - biomed 2010.

    Science.gov (United States)

    Zhao, Yue; Kang, Jinsheng; Wright, David

    2010-01-01

    This paper describes the methods and case studies of a novel synthetic vision and memory model for virtual human. The synthetic vision module simulates the biological / optical abilities and limitations of the human vision. The module is based on a series of collision detection between the boundary of virtual humans field of vision (FOV) volume and the surface of objects in a recreated 3D environment. The memory module simulates a short-term memory capability by employing a simplified memory structure (first-in-first-out stack). The synthetic vision and memory model has been integrated into a virtual human modelling project, Intelligent Virtual Modelling. The project aimed to improve the realism and autonomy of virtual humans.

  2. The moisture response of soil heterotrophic respiration: interaction with soil properties

    DEFF Research Database (Denmark)

    Moyano, F E; Vasilyeva, N; Bouckaert, L

    2012-01-01

    -driven analysis of soil moisture-respiration relations based on 90 soils. With the use of linear models we show how the relationship between soil heterotrophic respiration and different measures of soil moisture is consistently affected by soil properties. The empirical models derived include main effects......Soil moisture is of primary importance for predicting the evolution of soil carbon stocks and fluxes, both because it strongly controls organic matter decomposition and because it is predicted to change at global scales in the following decades. However, the soil functions used to model...... the heterotrophic respiration response to moisture have limited empirical support and introduce an uncertainty of at least 4% in global soil carbon stock predictions by 2100. The necessity of improving the representation of this relationship in models has been highlighted in recent studies. Here we present a data...

  3. Behavior genetic modeling of human fertility

    DEFF Research Database (Denmark)

    Rodgers, J L; Kohler, H P; Kyvik, K O

    2001-01-01

    Behavior genetic designs and analysis can be used to address issues of central importance to demography. We use this methodology to document genetic influence on human fertility. Our data come from Danish twin pairs born from 1953 to 1959, measured on age at first attempt to get pregnant (First...

  4. Pig models for the human heart failure syndrome

    DEFF Research Database (Denmark)

    Hunter, Ingrid; Terzic, Dijana; Zois, Nora Elisabeth

    2014-01-01

    Human heart failure remains a challenging illness despite advances in the diagnosis and treatment of heart failure patients. There is a need for further improvement of our understanding of the failing myocardium and its molecular deterioration. Porcine models provide an important research tool...... in this respect as molecular changes can be examined in detail, which is simply not feasible in human patients. However, the human heart failure syndrome is based on symptoms and signs, where pig models mostly mimic the myocardial damage, but without decisive data on clinical presentation and, therefore, a heart...... to elucidate the human heart failure syndrome....

  5. Human tissue models in cancer research: looking beyond the mouse.

    Science.gov (United States)

    Jackson, Samuel J; Thomas, Gareth J

    2017-08-01

    Mouse models, including patient-derived xenograft mice, are widely used to address questions in cancer research. However, there are documented flaws in these models that can result in the misrepresentation of human tumour biology and limit the suitability of the model for translational research. A coordinated effort to promote the more widespread development and use of 'non-animal human tissue' models could provide a clinically relevant platform for many cancer studies, maximising the opportunities presented by human tissue resources such as biobanks. A number of key factors limit the wide adoption of non-animal human tissue models in cancer research, including deficiencies in the infrastructure and the technical tools required to collect, transport, store and maintain human tissue for lab use. Another obstacle is the long-standing cultural reliance on animal models, which can make researchers resistant to change, often because of concerns about historical data compatibility and losing ground in a competitive environment while new approaches are embedded in lab practice. There are a wide range of initiatives that aim to address these issues by facilitating data sharing and promoting collaborations between organisations and researchers who work with human tissue. The importance of coordinating biobanks and introducing quality standards is gaining momentum. There is an exciting opportunity to transform cancer drug discovery by optimising the use of human tissue and reducing the reliance on potentially less predictive animal models. © 2017. Published by The Company of Biologists Ltd.

  6. Drosophila Melanogaster as an Emerging Translational Model of Human Nephrolithiasis

    Science.gov (United States)

    Miller, Joe; Chi, Thomas; Kapahi, Pankaj; Kahn, Arnold J.; Kim, Man Su; Hirata, Taku; Romero, Michael F.; Dow, Julian A.T.; Stoller, Marshall L.

    2013-01-01

    Purpose The limitations imposed by human clinical studies and mammalian models of nephrolithiasis have hampered the development of effective medical treatments and preventative measures for decades. The simple but elegant Drosophila melanogaster is emerging as a powerful translational model of human disease, including nephrolithiasis and may provide important information essential to our understanding of stone formation. We present the current state of research using D. melanogaster as a model of human nephrolithiasis. Materials and Methods A comprehensive review of the English language literature was performed using PUBMED. When necessary, authoritative texts on relevant subtopics were consulted. Results The genetic composition, anatomic structure and physiologic function of Drosophila Malpighian tubules are remarkably similar to those of the human nephron. The direct effects of dietary manipulation, environmental alteration, and genetic variation on stone formation can be observed and quantified in a matter of days. Several Drosophila models of human nephrolithiasis, including genetically linked and environmentally induced stones, have been developed. A model of calcium oxalate stone formation is among the most recent fly models of human nephrolithiasis. Conclusions The ability to readily manipulate and quantify stone formation in D. melanogaster models of human nephrolithiasis presents the urologic community with a unique opportunity to increase our understanding of this enigmatic disease. PMID:23500641

  7. Human tissue models in cancer research: looking beyond the mouse

    Directory of Open Access Journals (Sweden)

    Samuel J. Jackson

    2017-08-01

    Full Text Available Mouse models, including patient-derived xenograft mice, are widely used to address questions in cancer research. However, there are documented flaws in these models that can result in the misrepresentation of human tumour biology and limit the suitability of the model for translational research. A coordinated effort to promote the more widespread development and use of ‘non-animal human tissue’ models could provide a clinically relevant platform for many cancer studies, maximising the opportunities presented by human tissue resources such as biobanks. A number of key factors limit the wide adoption of non-animal human tissue models in cancer research, including deficiencies in the infrastructure and the technical tools required to collect, transport, store and maintain human tissue for lab use. Another obstacle is the long-standing cultural reliance on animal models, which can make researchers resistant to change, often because of concerns about historical data compatibility and losing ground in a competitive environment while new approaches are embedded in lab practice. There are a wide range of initiatives that aim to address these issues by facilitating data sharing and promoting collaborations between organisations and researchers who work with human tissue. The importance of coordinating biobanks and introducing quality standards is gaining momentum. There is an exciting opportunity to transform cancer drug discovery by optimising the use of human tissue and reducing the reliance on potentially less predictive animal models.

  8. Modeling cognition and disease using human glial chimeric mice

    DEFF Research Database (Denmark)

    Goldman, Steven A.; Nedergaard, Maiken; Windrem, Martha S.

    2015-01-01

    As new methods for producing and isolating human glial progenitor cells (hGPCs) have been developed, the disorders of myelin have become especially compelling targets for cell-based therapy. Yet as animal modeling of glial progenitor cell-based therapies has progressed, it has become clear......, oligodendrocytes as well. As a result, the recipient brains may become inexorably humanized with regards to their resident glial populations, yielding human glial chimeric mouse brains. These brains provide us a fundamentally new tool by which to assess the species-specific attributes of glia in modulating human...... for studying the human-specific contributions of glia to psychopathology, as well as to higher cognition. As such, the assessment of human glial chimeric mice may provide us new insight into the species-specific contributions of glia to human cognitive evolution, as well as to the pathogenesis of human...

  9. Human Digital Modeling & Hand Scanning Lab

    Data.gov (United States)

    Federal Laboratory Consortium — This laboratory incorporates specialized scanning equipment, computer workstations and software applications for the acquisition and analysis of digitized models of...

  10. Modelling Cerebral Blood Flow Autoregulation in Humans

    National Research Council Canada - National Science Library

    Panerai, R

    2001-01-01

    ...% of CBF regulatory,' mechanisms and their interaction with other haemodynamic variables such as intracranial pressure and blood gases, Mathematical models have been able to reproduce many known...

  11. Human performance models for computer-aided engineering

    Science.gov (United States)

    Elkind, Jerome I. (Editor); Card, Stuart K. (Editor); Hochberg, Julian (Editor); Huey, Beverly Messick (Editor)

    1989-01-01

    This report discusses a topic important to the field of computational human factors: models of human performance and their use in computer-based engineering facilities for the design of complex systems. It focuses on a particular human factors design problem -- the design of cockpit systems for advanced helicopters -- and on a particular aspect of human performance -- vision and related cognitive functions. By focusing in this way, the authors were able to address the selected topics in some depth and develop findings and recommendations that they believe have application to many other aspects of human performance and to other design domains.

  12. Mechanical Impedance Modeling of Human Arm: A survey

    Science.gov (United States)

    Puzi, A. Ahmad; Sidek, S. N.; Sado, F.

    2017-03-01

    Human arm mechanical impedance plays a vital role in describing motion ability of the upper limb. One of the impedance parameters is stiffness which is defined as the ratio of an applied force to the measured deformation of the muscle. The arm mechanical impedance modeling is useful in order to develop a better controller for system that interacts with human as such an automated robot-assisted platform for automated rehabilitation training. The aim of the survey is to summarize the existing mechanical impedance models of human upper limb so to justify the need to have an improved version of the arm model in order to facilitate the development of better controller of such systems with ever increase in complexity. In particular, the paper will address the following issue: Human motor control and motor learning, constant and variable impedance models, methods for measuring mechanical impedance and mechanical impedance modeling techniques.

  13. Human Spaceflight Architecture Model (HSFAM) Data Dictionary

    Science.gov (United States)

    Shishko, Robert

    2016-01-01

    HSFAM is a data model based on the DoDAF 2.02 data model with some for purpose extensions. These extensions are designed to permit quantitative analyses regarding stakeholder concerns about technical feasibility, configuration and interface issues, and budgetary and/or economic viability.

  14. Pig models for the human heart failure syndrome

    DEFF Research Database (Denmark)

    Hunter, Ingrid; Terzic, Dijana; Zois, Nora Elisabeth

    2014-01-01

    failure diagnosis. In perspective, pig models are in need of some verification in terms of the clinical definition of the experimental condition. After all, humans are not pigs, pigs are not humans, and the difference between the species needs to be better understood before pig models can fully be used......Human heart failure remains a challenging illness despite advances in the diagnosis and treatment of heart failure patients. There is a need for further improvement of our understanding of the failing myocardium and its molecular deterioration. Porcine models provide an important research tool...

  15. A Computational Model of Human Table Tennis for Robot Application

    Science.gov (United States)

    Mülling, Katharina; Peters, Jan

    Table tennis is a difficult motor skill which requires all basic components of a general motor skill learning system. In order to get a step closer to such a generic approach to the automatic acquisition and refinement of table tennis, we study table tennis from a human motor control point of view. We make use of the basic models of discrete human movement phases, virtual hitting points, and the operational timing hypothesis. Using these components, we create a computational model which is aimed at reproducing human-like behavior. We verify the functionality of this model in a physically realistic simulation of a Barrett WAM.

  16. Human performance modeling for system of systems analytics.

    Energy Technology Data Exchange (ETDEWEB)

    Dixon, Kevin R.; Lawton, Craig R.; Basilico, Justin Derrick; Longsine, Dennis E. (INTERA, Inc., Austin, TX); Forsythe, James Chris; Gauthier, John Henry; Le, Hai D.

    2008-10-01

    A Laboratory-Directed Research and Development project was initiated in 2005 to investigate Human Performance Modeling in a System of Systems analytic environment. SAND2006-6569 and SAND2006-7911 document interim results from this effort; this report documents the final results. The problem is difficult because of the number of humans involved in a System of Systems environment and the generally poorly defined nature of the tasks that each human must perform. A two-pronged strategy was followed: one prong was to develop human models using a probability-based method similar to that first developed for relatively well-understood probability based performance modeling; another prong was to investigate more state-of-art human cognition models. The probability-based modeling resulted in a comprehensive addition of human-modeling capability to the existing SoSAT computer program. The cognitive modeling resulted in an increased understanding of what is necessary to incorporate cognition-based models to a System of Systems analytic environment.

  17. A multisensory integration model of human stance control.

    Science.gov (United States)

    van der Kooij, H; Jacobs, R; Koopman, B; Grootenboer, H

    1999-05-01

    A model is presented to study and quantify the contribution of all available sensory information to human standing based on optimal estimation theory. In the model, delayed sensory information is integrated in such a way that a best estimate of body orientation is obtained. The model approach agrees with the present theory of the goal of human balance control. The model is not based on purely inverted pendulum body dynamics, but rather on a three-link segment model of a standing human on a movable support base. In addition, the model is non-linear and explicitly addresses the problem of multisensory integration and neural time delays. A predictive element is included in the controller to compensate for time delays, necessary to maintain erect body orientation. Model results of sensory perturbations on total body sway closely resemble experimental results. Despite internal and external perturbations, the controller is able to stabilise the model of an inherently unstable standing human with neural time delays of 100 ms. It is concluded, that the model is capable of studying and quantifying multisensory integration in human stance control. We aim to apply the model in (1) the design and development of prostheses and orthoses and (2) the diagnosis of neurological balance disorders.

  18. Pellet culture model for human primary osteoblasts

    OpenAIRE

    K Jähn; RG Richards; CW Archer; MJ Stoddart

    2010-01-01

    In vitro monolayer culture of human primary osteoblasts (hOBs) often shows unsatisfactory results for extracellular matrix deposition, maturation and calcification. Nevertheless, monolayer culture is still the method of choice for in vitro differentiation of primary osteoblasts. We believe that the delay in mature ECM production by the monolayer cultured osteoblasts is determined by their state of cell maturation. A functional relationship between the inhibition of osteoblast proliferation an...

  19. Human reconstructed skin xenografts on mice to model skin physiology.

    Science.gov (United States)

    Salgado, Giorgiana; Ng, Yi Zhen; Koh, Li Fang; Goh, Christabelle S M; Common, John E

    Xenograft models to study skin physiology have been popular for scientific use since the 1970s, with various developments and improvements to the techniques over the decades. Xenograft models are particularly useful and sought after due to the lack of clinically relevant animal models in predicting drug effectiveness in humans. Such predictions could in turn boost the process of drug discovery, since novel drug compounds have an estimated 8% chance of FDA approval despite years of rigorous preclinical testing and evaluation, albeit mostly in non-human models. In the case of skin research, the mouse persists as the most popular animal model of choice, despite its well-known anatomical differences with human skin. Differences in skin biology are especially evident when trying to dissect more complex skin conditions, such as psoriasis and eczema, where interactions between the immune system, epidermis and the environment likely occur. While the use of animal models are still considered the gold standard for systemic toxicity studies under controlled environments, there are now alternative models that have been approved for certain applications. To overcome the biological limitations of the mouse model, research efforts have also focused on "humanizing" the mice model to better recapitulate human skin physiology. In this review, we outline the different approaches undertaken thus far to study skin biology using human tissue xenografts in mice and the technical challenges involved. We also describe more recent developments to generate humanized multi-tissue compartment mice that carry both a functioning human immune system and skin xenografts. Such composite animal models provide promising opportunities to study drugs, disease and differentiation with greater clinical relevance. Copyright © 2017 International Society of Differentiation. Published by Elsevier B.V. All rights reserved.

  20. Impacts of temperature on primary productivity and respiration in naturally structured macroalgal assemblages.

    Directory of Open Access Journals (Sweden)

    Leigh W Tait

    Full Text Available Rising global temperatures caused by human-mediated change has already triggered significant responses in organismal physiology, distribution and ecosystem functioning. Although the effects of rising temperature on the physiology of individual organisms are well understood, the effect on community-wide processes has remained elusive. The fixation of carbon via primary productivity is an essential ecosystem function and any shifts in the balance of primary productivity and respiration could alter the carbon balance of ecosystems. Here we show through a series of tests that respiration of naturally structured algal assemblages in southern New Zealand greatly increases with rising temperature, with implications for net primary productivity (NPP. The NPP of in situ macroalgal assemblages was minimally affected by natural temperature variation, possibly through photo-acclimation or temperature acclimation responses, but respiration rates and compensating irradiance were negatively affected. However, laboratory experiments testing the impacts of rising temperature on several photosynthetic parameters showed a decline in NPP, increasing respiration rates and increasing compensating irradiance. The respiration Q10 of laboratory assemblages (the difference in metabolic rates over 10°C averaged 2.9 compared to a Q10 of 2 often seen in other autotrophs. However, gross primary productivity (GPP Q10 averaged 2, indicating that respiration was more severely affected by rising temperature. Furthermore, combined high irradiance and high temperature caused photoinhibition in the laboratory, and resulted in 50% lower NPP at high irradiance. Our study shows that communities may be more severely affected by rising global temperatures than would be expected by responses of individual species. In particular, enhanced respiration rates and rising compensation points have the potential to greatly affect the carbon balance of macroalgal assemblages through declines in

  1. A Human View Model for Socio-Technical Interactions

    Science.gov (United States)

    Handley, Holly A.; Tolk, Andreas

    2012-01-01

    The Human View was developed as an additional architectural viewpoint to focus on the human part of a system. The Human View can be used to collect and organize data in order to understand how human operators interact and impact the other elements of a system. This framework can also be used to develop a model to describe how humans interact with each other in network enabled systems. These socio-technical interactions form the foundation of the emerging area of Human Interoperability. Human Interoperability strives to understand the relationships required between human operators that impact collaboration across networked environments, including the effect of belonging to different organizations. By applying organizational relationship concepts from network theory to the Human View elements, and aligning these relationships with a model developed to identify layers of coalition interoperability, the conditions for different levels for Human Interoperability for network enabled systems can be identified. These requirements can then be captured in the Human View products to improve the overall network enabled system.

  2. Formal modelling techniques in human-computer interaction

    NARCIS (Netherlands)

    de Haan, G.; de Haan, G.; van der Veer, Gerrit C.; van Vliet, J.C.

    1991-01-01

    This paper is a theoretical contribution, elaborating the concept of models as used in Cognitive Ergonomics. A number of formal modelling techniques in human-computer interaction will be reviewed and discussed. The analysis focusses on different related concepts of formal modelling techniques in

  3. A computationally efficient electrophysiological model of human ventricular cells

    NARCIS (Netherlands)

    Bernus, O.; Wilders, R.; Zemlin, C. W.; Verschelde, H.; Panfilov, A. V.

    2002-01-01

    Recent experimental and theoretical results have stressed the importance of modeling studies of reentrant arrhythmias in cardiac tissue and at the whole heart level. We introduce a six-variable model obtained by a reformulation of the Priebe-Beuckelmann model of a single human ventricular cell. The

  4. Some aspects of statistical modeling of human-error probability

    International Nuclear Information System (INIS)

    Prairie, R.R.

    1982-01-01

    Human reliability analyses (HRA) are often performed as part of risk assessment and reliability projects. Recent events in nuclear power have shown the potential importance of the human element. There are several on-going efforts in the US and elsewhere with the purpose of modeling human error such that the human contribution can be incorporated into an overall risk assessment associated with one or more aspects of nuclear power. An effort that is described here uses the HRA (event tree) to quantify and model the human contribution to risk. As an example, risk analyses are being prepared on several nuclear power plants as part of the Interim Reliability Assessment Program (IREP). In this process the risk analyst selects the elements of his fault tree that could be contributed to by human error. He then solicits the HF analyst to do a HRA on this element

  5. LIMITATION OF SOIL RESPIRATION DURING DRY PERIOD

    Czech Academy of Sciences Publication Activity Database

    Pavelka, Marian; Janouš, Dalibor; Acosta, Manuel

    2003-01-01

    Roč. 16, - (2003), s. 47-52. ISBN 80-7157-297-7 R&D Projects: GA MŠk LN00A141; GA AV ČR IBS6087005 Institutional research plan: CEZ:AV0Z6087904 Keywords : moisture * Norway spruce * precipitation * respiration * soil CO2 efflux Subject RIV: EH - Ecology, Behaviour

  6. Respiration during sleep in Huntington's chorea

    NARCIS (Netherlands)

    Bollen, E. L.; den Heijer, J. C.; Ponsioen, C.; Kramer, C.; van der Velde, E. A.; van Dijk, J. G.; Roos, R. A.; Kamphuisen, H. A.; Buruma, O. J.

    1988-01-01

    In view of recent reports on lower brainstem dysfunction in Huntington's chorea, we studied respiration during sleep in 12 patients with Huntington's chorea (HC) and in controls. There were no statistically significant differences between patients and controls with respect to apnea periods,

  7. THE EFFECT OF PHYSICAL DAMAGE ON RESPIRATION ...

    African Journals Online (AJOL)

    The drops were meant to simulate handling, road and vehicle conditions that the tomatoes are subjected to from the areas of production to market outlets. Respiration, compositional ... The level of ripeness followed the reverse trend to that of chlorophyll as it was measured in terms of the attainment of red color. Decay was ...

  8. The Nucleus Retroambiguus Control of Respiration

    NARCIS (Netherlands)

    Subramanian, Hari H.; Holstege, Gert

    2009-01-01

    The role of the nucleus retroambiguus (NRA) in the context of respiration control has been subject of debate for considerable time. To solve this problem, we chemically (using D, L-homocysteic acid) stimulated the NRA in unanesthetized precollicularly decerebrated cats and studied the respiratory

  9. 42 CFR 84.1130 - Respirators; description.

    Science.gov (United States)

    2010-10-01

    ...; Pesticide; Paint Spray; Powered Air-Purifying High Efficiency Respirators and Combination Gas Masks § 84... respective vapors, or from the chemical reaction between their respective vapors and gases. (3) Air-purifying...) Front-mounted or back-mounted gas masks; (2) Chin-style gas mask; (3) Chemical cartridge; (4) Air...

  10. Metabolic interactions between methanogenic consortia and anaerobic respiring bacteria

    DEFF Research Database (Denmark)

    Stams, A.J.; Oude Elferink, S.J.; Westermann, Peter

    2003-01-01

    Most types of anaerobic respiration are able to outcompete methanogenic consortia for common substrates if the respective electron acceptors are present in sufficient amounts. Furthermore, several products or intermediate compounds formed by anaerobic respiring bacteria are toxic to methanogenic...

  11. Partitioning of ecosystem respiration in a beech forest

    DEFF Research Database (Denmark)

    Brændholt, Andreas; Ibrom, Andreas; Larsen, Klaus Steenberg

    2018-01-01

    of Reco in a temperate beech forest at diel, seasonal and annual time scales. Reco was measured by eddy covariance while respiration rates from soil, tree stems and isolated coarse tree roots were measured bi-hourly by an automated closed-chamber system. Soil respiration (Rsoil) was measured in intact...... with the highest respiration rates around 13:00-15:00 CET for Rstem, and the highest respiration seen from 9:00–15:00 for Rroot. In contrast, Rsoil showed the lowest respiration during daytime with no clear difference in the diel pattern between the intact and trenched soil plots. Finally, we calculated annual......Terrestrial ecosystem respiration (Reco) represents a major component of the global carbon cycle. It consists of many sub-components, such as aboveground plant respiration and belowground root and microbial respiration, each of which may respond differently to abiotic factors, and thus to global...

  12. Metabolic interactions between methanogenic consortia and anaerobic respiring bacteria

    DEFF Research Database (Denmark)

    Stams, A.J.; Oude Elferink, S.J.; Westermann, Peter

    2003-01-01

    Most types of anaerobic respiration are able to outcompete methanogenic consortia for common substrates if the respective electron acceptors are present in sufficient amounts. Furthermore, several products or intermediate compounds formed by anaerobic respiring bacteria are toxic to methanogenic ...

  13. Diet induced thermogenesis measured over 24h in a respiration chamber: effect of diet composition.

    NARCIS (Netherlands)

    Westerterp, K.R.; Wilson, S.A.; Rolland, V.

    1999-01-01

    Department of Human Biology, Maastricht University, The Netherlands. OBJECTIVE: To study the effect of diet composition on diet-induced thermogenesis (DIT) over 24h in a respiration chamber. SUBJECTS: Eight healthy female volunteers (age 27 +/- 3 y; body mass index, BMI 23 +/- 3 kg/m2). DIETS: A

  14. Impact of Mining Waste on Airborne Respirable Particulates in Northeastern Oklahoma, United States

    Science.gov (United States)

    Atmospheric dispersion of particles from mine waste is potentially an important route of human exposure to metals in communities close to active and abandoned mining areas. In this study, we assessed sources of mass and metal concentrations in two size fractions of respirable pa...

  15. A Review on Human Respiratory Modeling.

    Science.gov (United States)

    Ghafarian, Pardis; Jamaati, Hamidreza; Hashemian, Seyed Mohammadreza

    2016-01-01

    Input impedance of the respiratory system is measured by forced oscillation technique (FOT). Multiple prior studies have attempted to match the electromechanical models of the respiratory system to impedance data. Since the mechanical behavior of airways and the respiratory system as a whole are similar to an electrical circuit in a combination of series and parallel formats some theories were introduced according to this issue. It should be noted that, the number of elements used in these models might be less than those required due to the complexity of the pulmonary-chest wall anatomy. Various respiratory models have been proposed based on this idea in order to demonstrate and assess the different parts of respiratory system related to children and adults data. With regard to our knowledge, some of famous respiratory models in related to obstructive, restrictive diseases and also Acute Respiratory Distress Syndrome (ARDS) are reviewed in this article.

  16. Human Communication--A New Model.

    Science.gov (United States)

    McLeish, John

    1978-01-01

    Pavlov's organism-in-the-environment model was adapted to a functional analysis of communication, expecially abstract and symbolic activities. A classification of discrimination response and reinforcement patterns was given. (CP)

  17. Human Endothelial Cell Models in Biomaterial Research.

    Science.gov (United States)

    Hauser, Sandra; Jung, Friedrich; Pietzsch, Jens

    2017-03-01

    Endothelial cell (EC) models have evolved as important tools in biomaterial research due to ubiquitously occurring interactions between implanted materials and the endothelium. However, screening the available literature has revealed a gap between material scientists and physiologists in terms of their understanding of these biomaterial-endothelium interactions and their relative importance. Consequently, EC models are often applied in nonphysiological experimental setups, or too extensive conclusions are drawn from their results. The question arises whether this might be one reason why, among the many potential biomaterials, only a few have found their way into the clinic. In this review, we provide an overview of established EC models and possible selection criteria to enable researchers to determine the most reliable and relevant EC model to use. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Model-Based approaches to Human-Automation Systems Design

    DEFF Research Database (Denmark)

    Jamieson, Greg A.; Andersson, Jonas; Bisantz, Ann

    2012-01-01

    Human-automation interaction in complex systems is common, yet design for this interaction is often conducted without explicit consideration of the role of the human operator. Fortunately, there are a number of modeling frameworks proposed for supporting this design activity. However...... (and reportedly one or two critics) can engage one another on several agreed questions about such frameworks. The goal is to aid non-aligned practitioners in choosing between alternative frameworks for their human-automation interaction design challenges....

  19. Relevance of animal models to human tardive dyskinesia

    Directory of Open Access Journals (Sweden)

    Blanchet Pierre J

    2012-03-01

    Full Text Available Abstract Tardive dyskinesia remains an elusive and significant clinical entity that can possibly be understood via experimentation with animal models. We conducted a literature review on tardive dyskinesia modeling. Subchronic antipsychotic drug exposure is a standard approach to model tardive dyskinesia in rodents. Vacuous chewing movements constitute the most common pattern of expression of purposeless oral movements and represent an impermanent response, with individual and strain susceptibility differences. Transgenic mice are also used to address the contribution of adaptive and maladaptive signals induced during antipsychotic drug exposure. An emphasis on non-human primate modeling is proposed, and past experimental observations reviewed in various monkey species. Rodent and primate models are complementary, but the non-human primate model appears more convincingly similar to the human condition and better suited to address therapeutic issues against tardive dyskinesia.

  20. Computational models of human vision with applications

    Science.gov (United States)

    Wandell, Brian A.

    1987-01-01

    The research program supported by this grant was initiated in l977 by the Joint Institute for Aeronautics and Acoustics of the Department of Aeronautics and Astronautics at Stanford University. The purpose of the research was to study human performance with the goal of improving the design of flight instrumentation. By mutual agreement between the scientists at NASA-Ames and Stanford, all research activities in this area were consolidated into a single funding mechanism, NCC 2-307 (Center of Excellence Grant, 7/1/84 - present). This is the final report on this research grant.

  1. Acceptable respiratory protection program and LASL respirator research

    Energy Technology Data Exchange (ETDEWEB)

    Skaggs, B.J.

    1979-01-01

    A short history is presented on the LASL Respiratory Protection Training Programs. Then a discussion is given on the major points of an acceptable respiratory protection program utilizing the points required by the Occupational, Safety, and Health Administration (OSHA) Regulation 29 CFR 1910.134. Contributions to respirator research are reviewed. Discussion is presented under the following section headings: program administration; respirator selection; respirator use; fitting and training; respirator maintenance; medical clearance and surveillance; special problems; program evaluation; and documentation (records).

  2. Contribution of root to soil respiration and carbon balance in ...

    Indian Academy of Sciences (India)

    Soil respiration varied from 2.5 to 11.9 g CO2 m-2 d-1 and from 1.5 to 9.3 g CO2 m-2 d-1, and the contribution of root respiration to total soil respiration from 38% to 76% and from 25% to 72% in Communities 1 and 2, respectively. During the growing season (May–September), soil respiration, shoot biomass, live root ...

  3. Acceptable respiratory protection program and LASL respirator research

    International Nuclear Information System (INIS)

    Skaggs, B.J.

    1979-01-01

    A short history is presented on the LASL Respiratory Protection Training Programs. Then a discussion is given on the major points of an acceptable respiratory protection program utilizing the points required by the Occupational, Safety, and Health Administration (OSHA) Regulation 29 CFR 1910.134. Contributions to respirator research are reviewed. Discussion is presented under the following section headings: program administration; respirator selection; respirator use; fitting and training; respirator maintenance; medical clearance and surveillance; special problems; program evaluation; and documentation

  4. Quantitative modeling of human performance in complex, dynamic systems

    National Research Council Canada - National Science Library

    Baron, Sheldon; Kruser, Dana S; Huey, Beverly Messick

    1990-01-01

    ... Sheldon Baron, Dana S. Kruser, and Beverly Messick Huey, editors Panel on Human Performance Modeling Committee on Human Factors Commission on Behavioral and Social Sciences and Education National Research Council NATIONAL ACADEMY PRESS Washington, D.C. 1990 Copyrightoriginal retained, the be not from cannot book, paper original however, for version forma...

  5. How do humans inspect BPMN models: an exploratory study

    DEFF Research Database (Denmark)

    Haisjackl, Cornelia; Soffer, Pnina; Lim, Shao Yi

    2016-01-01

    by humans, what strategies are taken, what challenges arise, and what cognitive processes are involved. This paper contributes toward such an understanding and reports an exploratory study investigating how humans identify and classify quality issues in BPMN process models. Providing preliminary answers...

  6. Pharmacological migraine provocation: a human model of migraine

    DEFF Research Database (Denmark)

    Ashina, Messoud; Hansen, Jakob Møller

    2010-01-01

    for migraine mechanisms. So far, however, animal models cannot predict the efficacy of new therapies for migraine. Because migraine attacks are fully reversible and can be aborted by therapy, the headache- or migraine-provoking property of naturally occurring signaling molecules can be tested in a human model......In vitro studies have contributed to the characterization of receptors in cranial blood vessels and the identification of possible new antimigraine agents. Animal models enable the study of vascular responses, neurogenic inflammation, and peptide release, and thus have provided leads in the search....... If a naturally occurring substance can provoke migraine in human patients, then it is likely, although not certain, that blocking its effect will be effective in the treatment of acute migraine attacks. To this end, a human in vivo model of experimental headache and migraine in humans has been developed...

  7. Can inter-human communications be modeled as "autopoietic"?

    NARCIS (Netherlands)

    Leydesdorff, L.

    2014-01-01

    Open peer commentary on the article "Social Autopoiesis?" by Hugo Urrestarazu. Upshot: The dynamics of expectations in inter-human communications can be modelled as "autopoiesis." Consciousness and communications couple not only structurally (Maturana), but also penetrate each other reflexively

  8. Dynamic Human Body Modeling Using a Single RGB Camera.

    Science.gov (United States)

    Zhu, Haiyu; Yu, Yao; Zhou, Yu; Du, Sidan

    2016-03-18

    In this paper, we present a novel automatic pipeline to build personalized parametric models of dynamic people using a single RGB camera. Compared to previous approaches that use monocular RGB images, our system can model a 3D human body automatically and incrementally, taking advantage of human motion. Based on coarse 2D and 3D poses estimated from image sequences, we first perform a kinematic classification of human body parts to refine the poses and obtain reconstructed body parts. Next, a personalized parametric human model is generated by driving a general template to fit the body parts and calculating the non-rigid deformation. Experimental results show that our shape estimation method achieves comparable accuracy with reconstructed models using depth cameras, yet requires neither user interaction nor any dedicated devices, leading to the feasibility of using this method on widely available smart phones.

  9. Human casualties in earthquakes: Modelling and mitigation

    Science.gov (United States)

    Spence, R.J.S.; So, E.K.M.

    2011-01-01

    Earthquake risk modelling is needed for the planning of post-event emergency operations, for the development of insurance schemes, for the planning of mitigation measures in the existing building stock, and for the development of appropriate building regulations; in all of these applications estimates of casualty numbers are essential. But there are many questions about casualty estimation which are still poorly understood. These questions relate to the causes and nature of the injuries and deaths, and the extent to which they can be quantified. This paper looks at the evidence on these questions from recent studies. It then reviews casualty estimation models available, and finally compares the performance of some casualty models in making rapid post-event casualty estimates in recent earthquakes.

  10. [Effect of grazing on the temperature sensitivity of soil respiration in Hulunber meadow steppe].

    Science.gov (United States)

    Wang, Xu; Yan, Rui-Rui; Deng, Yu; Yan, Yu-Chun; Xin, Xiao-Ping

    2014-05-01

    Grazing is one of the major human activities which lead to disturbance on grassland ecosystem. Quantifying the effect of grazing on the temperature sensitivity of soil respiration ( Q10 ) is essential for accurate assessment of carbon budget in grassland ecosystem. This study was conducted on the grazing gradients experiment platform in Hulunber meadow steppe. Soil respiration was measured by a dynamic closed chamber method (equipped with Li 6400-09, Lincoln, NE, USA) during the growing season in 2011. The results showed that soil respiration had significant seasonal variation and the maximum occurred in July, which was mainly dominated by temperature. The order of average soil respiration during the period from May to September in different treatments was G1 > GO > G2 > G3 > G4 > G5. Comparing with non-grazing treatment, Q10 under heavy grazing conditions (0. 92 Au hm-2) was reduced by about 10% , and was increased a little under light grazing conditions (0. 23 Au hm-2). There was a significant negative correlation between Q15 and grazing intensities (r = 0. 944, P temperature sensitivity of soil respiration to different degrees. The Q10 under different grazing gradients had positive linear regression relationships with aboveground biomass, belowground biomass, soil organic carbon and soil moisture. They could explain 71.0%-85.2% variations of Q10. It was suggested that the variation of Q10 was mainly determined by the change of biotic and environmental factors due to grazing.

  11. Advanced testing method to evaluate the performance of respirator filter media.

    Science.gov (United States)

    Wang, Qiang; Golshahi, Laleh; Chen, Da-Ren

    2016-10-02

    Filter media for respirator applications are typically exposed to the cyclic flow condition, which is different from the constant flow condition adopted in filter testing standards. To understand the real performance of respirator filter media in the field it is required to investigate the penetration of particles through respirator filters under cyclic flow conditions representing breathing flow patterns of human beings. This article reports a new testing method for studying the individual effect of breathing frequency (BF) and peak inhalation flow rate (PIFR) on the particle penetration through respirator filter media. The new method includes the use of DMA (Differential Mobility Analyzer)-classified particles having the most penetrating particle size, MPPS (at the constant flowrate of equivalent mean inhalation flow rate, MIFR) as test aerosol. Two condensation particle counters (CPCs) are applied to measure the particle concentrations at the upstream and downstream of test filter media at the same time. Given the 10 Hz sampling time of CPCs, close-to-instantaneous particle penetration could be measured. A pilot study was performed to demonstrate the new testing method. It is found that the effect of BF on the particle penetration of test respirator filter media is of importance at all the tested peak inhalation flow rates (PIFRs), which is different from those reported in the previous work.

  12. Generating Phenotypical Erroneous Human Behavior to Evaluate Human-automation Interaction Using Model Checking.

    Science.gov (United States)

    Bolton, Matthew L; Bass, Ellen J; Siminiceanu, Radu I

    2012-11-01

    Breakdowns in complex systems often occur as a result of system elements interacting in unanticipated ways. In systems with human operators, human-automation interaction associated with both normative and erroneous human behavior can contribute to such failures. Model-driven design and analysis techniques provide engineers with formal methods tools and techniques capable of evaluating how human behavior can contribute to system failures. This paper presents a novel method for automatically generating task analytic models encompassing both normative and erroneous human behavior from normative task models. The generated erroneous behavior is capable of replicating Hollnagel's zero-order phenotypes of erroneous action for omissions, jumps, repetitions, and intrusions. Multiple phenotypical acts can occur in sequence, thus allowing for the generation of higher order phenotypes. The task behavior model pattern capable of generating erroneous behavior can be integrated into a formal system model so that system safety properties can be formally verified with a model checker. This allows analysts to prove that a human-automation interactive system (as represented by the model) will or will not satisfy safety properties with both normative and generated erroneous human behavior. We present benchmarks related to the size of the statespace and verification time of models to show how the erroneous human behavior generation process scales. We demonstrate the method with a case study: the operation of a radiation therapy machine. A potential problem resulting from a generated erroneous human action is discovered. A design intervention is presented which prevents this problem from occurring. We discuss how our method could be used to evaluate larger applications and recommend future paths of development.

  13. Generating Phenotypical Erroneous Human Behavior to Evaluate Human-automation Interaction Using Model Checking

    Science.gov (United States)

    Bolton, Matthew L.; Bass, Ellen J.; Siminiceanu, Radu I.

    2012-01-01

    Breakdowns in complex systems often occur as a result of system elements interacting in unanticipated ways. In systems with human operators, human-automation interaction associated with both normative and erroneous human behavior can contribute to such failures. Model-driven design and analysis techniques provide engineers with formal methods tools and techniques capable of evaluating how human behavior can contribute to system failures. This paper presents a novel method for automatically generating task analytic models encompassing both normative and erroneous human behavior from normative task models. The generated erroneous behavior is capable of replicating Hollnagel’s zero-order phenotypes of erroneous action for omissions, jumps, repetitions, and intrusions. Multiple phenotypical acts can occur in sequence, thus allowing for the generation of higher order phenotypes. The task behavior model pattern capable of generating erroneous behavior can be integrated into a formal system model so that system safety properties can be formally verified with a model checker. This allows analysts to prove that a human-automation interactive system (as represented by the model) will or will not satisfy safety properties with both normative and generated erroneous human behavior. We present benchmarks related to the size of the statespace and verification time of models to show how the erroneous human behavior generation process scales. We demonstrate the method with a case study: the operation of a radiation therapy machine. A potential problem resulting from a generated erroneous human action is discovered. A design intervention is presented which prevents this problem from occurring. We discuss how our method could be used to evaluate larger applications and recommend future paths of development. PMID:23105914

  14. Separating autotrophic respiration due to roots from soil ...

    African Journals Online (AJOL)

    Soil respiration is the largest component of ecosystem respiration but little is known about it and its components in parkland systems. We therefore conducted an experiment to estimate the amount of CO2 respired and to partition it into soil, tree root and crop root contributions in parkland systems in Burkina Faso.

  15. 21 CFR 892.1970 - Radiographic ECG/respirator synchronizer.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Radiographic ECG/respirator synchronizer. 892.1970... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1970 Radiographic ECG/respirator synchronizer. (a) Identification. A radiographic ECG/respirator synchronizer is a device intended to be used to...

  16. 20 CFR 718.303 - Death from a respirable disease.

    Science.gov (United States)

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Death from a respirable disease. 718.303... from a respirable disease. (a)(1) If a deceased miner was employed for ten or more years in one or more coal mines and died from a respirable disease, there shall be a rebuttable presumption that his or her...

  17. 20 CFR 410.462 - Presumption relating to respirable disease.

    Science.gov (United States)

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Presumption relating to respirable disease... Pneumoconiosis § 410.462 Presumption relating to respirable disease. (a) Even though the existence of... was employed for 10 years or more in the Nation's coal mines and died from a respirable disease, it...

  18. Induction by ethylene of cyanide-resistant respiration

    Energy Technology Data Exchange (ETDEWEB)

    Solomos, T.; Laties, G.G.

    1976-05-17

    Ethylene and cyanide induce an increase in respiration in a variety of plant tissues, whereas ethylene has no effect on tissues whose respiration is strongly inhibited by cyanide. It is suggested that the existence of a cyanide-insensitive electron transport path is a prerequisite for stimulation of respiration by ethylene.

  19. Soil Respiration Declines Following Beetle - Induced Forest Mortality in a Lodgepole Pine Forest

    Science.gov (United States)

    Borkhuu, B.; Peckham, S. D.; Norton, U.; Ewers, B. E.; Pendall, E.

    2014-12-01

    Lodgepole pine (Pinus contorta var. latifolia) forests in northern Colorado and southeast Wyoming have been undergoing a major mortality event owing to mountain pine beetle (Dendroctonus ponderosae) infestation since 2007. We studied biotic and abiotic drivers of growing season soil respiration in four mature stands experiencing different levels of mortality between 2008 and 2012 in the Medicine Bow Mountains, southeastern Wyoming, USA. For five years, beetle infestation significantly altered forest structure. Stand mortality was 30% and more than 80% in stands with the lowest and highest mortality, respectively. Understory vegetation cover increased by 50% for five years following beetle infestation. Needlefall was increased by more than 50% during first two years of beetle infestation compared to the pre-disturbance period. We did not observe an immediate increase in soil respiration following beetle infestation as suggested by some researchers. Soil respiration rates in midsummer ranged from 1.4 ± 0.1 μmol m-2 s-1 in stands with highest mortality to 3.1 ± 0.2 μmol m-2s-1 in uninfested stand. Live tree basal area was the dominant factor controlling soil respiration, explaining more than 60% of the interannual and spatial variations in response to the disturbance. In addition, soil respiration was significantly correlated with fine root biomass, which explained 55% of variations, providing strong evidence that autotrophic respiration dominated the forest soil respiration flux. Furthermore, the seasonality of soil respiration was controlled mainly by mean monthly precipitation and mid-day photosynthetically active radiation. Each factor predicted from 30% to 50% of seasonal soil respiration variability with the highest correlation coefficients in stand with the lowest mortality. Our results clearly indicate that the reduction of photosynthesis in trees over the infestation period significantly reduced soil respiration. The remaining activity in dead stands may

  20. SDF-1/CXCL12 modulates mitochondrial respiration of immature blood cells in a bi-phasic manner.

    Science.gov (United States)

    Messina-Graham, Steven; Broxmeyer, Hal

    2016-05-01

    SDF-1/CXCL12 is a potent chemokine required for the homing and engraftment of hematopoietic stem and progenitor cells. Previous data from our group has shown that in an SDF-1/CXCL12 transgenic mouse model, lineage(-) Sca-1(+) c-Kit(+) (LSK) bone marrow cells have reduced mitochondrial membrane potential versus wild-type. These results suggested that SDF-1/CXCL12 may function to keep mitochondrial respiration low in immature blood cells in the bone marrow. Low mitochondrial metabolism helps to maintain low levels of reactive oxygen species (ROS), which can influence differentiation. To test whether SDF-1/CXCL12 regulates mitochondrial metabolism, we employed the human leukemia cell line HL-60, that expresses high levels of the SDF-1/CXCL12 receptor, CXCR4, as a model of hematopoietic progenitor cells in vitro. We treated HL-60 cells with SDF-1/CXCL12 for 2 and 24h. Oxygen consumption rates (OCR), mitochondrial-associated ATP production, mitochondrial mass, and mitochondrial membrane potential of HL-60 cells were significantly reduced at 2h and increased at 24h as compared to untreated control cells. These biphasic effects of SDF-1/CXCL12 were reproduced with lineage negative primary mouse bone marrow cells, suggesting a novel function of SDF-1/CXCL12 in modulating mitochondrial respiration by regulating mitochondrial oxidative phosphorylation, ATP production and mitochondrial content. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. [Biomechanics and regulation of the external respiration in the conditions of 5-day dry immersion].

    Science.gov (United States)

    Popova, Iu A; Suvorov, A V; D'iachenko, A I; Kolesnikov, V I

    2011-01-01

    The work was concerned with evaluation of the external respiration function and regulation in healthy human subjects participating in simulation of the microgravity effects by dry immersion (DI). In the baseline data collection period, in DI (days 2 and 4) and after DI completion pulmonary volumes were registered, the ratio of thoracic and abdominal components of quiet breathing and respiratory maneuvers calculated, and parameters of respiration regulation, i.e. length of breath-holding and ability to voluntary control breathing motions, were determined. It was shown that breathing pattern did not undergo gross changes in immersion as compared with pre-DI test data; however, inspiratory reserve volume grew (p immersion. We believe that similar to microgravity, exposure in DI produces regular alterations of pulmonary RV (partly because of changed body position), thoracic-abdominal ratio in breathing motions, and shifts in voluntary respiration regulation.

  2. Fruit removal increases root-zone respiration in cucumber

    Science.gov (United States)

    Kläring, H.-P.; Hauschild, I.; Heißner, A.

    2014-01-01

    Background and Aims Many attempts have been made to avoid the commonly observed fluctuations in fruit initiation and fruit growth in crop plants, particularly in cucumber (Cucumis sativus). Weak sinks of the fruit have been assumed to result in low sink/source ratios for carbohydrates, which may inhibit photosynthesis. This study focuses on the effects of low sink–source ratios on photosynthesis and respiration, and in particular root-zone respiration. Methods Mature fruit-bearing cucumber plants were grown in an aerated nutrient solution. The root containers were designed as open chambers to allow measurement of CO2 gas exchange in the root zone. A similar arrangement in a gas-exchange cuvette enabled simultaneous measurements of CO2 exchange in the shoot and root zones. Key Results Reducing the sinks for carbohydrates by removing all fruit from the plants always resulted in a doubling of CO2 exchange in the root zone within a few hours. However, respiration of the shoot remained unaffected and photosynthesis was only marginally reduced, if at all. Conclusions The results suggest that the increased level of CO2 gas exchange in the root zone after removing the carbon sinks in the shoot is due primarily to the exudation of organic compounds by the roots and their decomposition by micro-organisms. This hypothesis must be tested in further experiments, but if proved correct it would make sense to include carbon leakage by root exudation in cucumber production models. In contrast, inhibition of photosynthesis was measurable only at zero fruit load, a situation that does not occur in cucumber production systems, and models that estimate production can therefore ignore (end-product) inhibition of photosynthesis. PMID:25301817

  3. Comparison of the Gene Expression Profiles of Human Hematopoietic Stem Cells between Humans and a Humanized Xenograft Model.

    Science.gov (United States)

    Matsuzawa, Hideyuki; Matsushita, Hiromichi; Yahata, Takashi; Tanaka, Masayuki; Ando, Kiyoshi

    2017-04-20

    The aim of this study is to evaluate the feasibility of NOD/Shi-scid-IL2Rγ null (NOG) mice transplanted with human CD34 + /CD38 - /Lin -/low hematopoietic cells from cord blood (CB) as an experimental model of the gene expression in human hematopoiesis. We compared the gene expressions of human CD34 + /CD38 - /Lin -/low cells from human bone marrow (BM) and in xenograft models. The microarray data revealed that 25 KEGG pathways were extracted from the comparison of human CD34 + /CD38 - /Lin -/low HSCs between CB and BM, and that 17 of them--which were mostly related to cellular survival, RNA metabolism and lymphoid development--were shared with the xenograft model. When the probes that were commonly altered in CD34 + /CD38 - /Lin -/low cells from both human and xenograft BM were analyzed, most of them, including the genes related hypoxia, hematopoietic differentiation, epigenetic modification, translation initiation, and RNA degradation, were downregulated. These alterations of gene expression suggest a reduced differentiation capacity and likely include key alterations of gene expression for settlement of CB CD34 + /CD38 - /Lin -/low cells in BM. Our findings demonstrate that the xenograft model of human CB CD34 + /CD38 - /Lin -/low cells using NOG mice was useful, at least in part, for the evaluation of the gene expression profile of human hematopoietic stem cells.

  4. Modeling human disease using organotypic cultures

    DEFF Research Database (Denmark)

    Schweiger, Pawel J; Jensen, Kim B

    2016-01-01

    Reliable disease models are needed in order to improve quality of healthcare. This includes gaining better understanding of disease mechanisms, developing new therapeutic interventions and personalizing treatment. Up-to-date, the majority of our knowledge about disease states comes from in vivo...

  5. A computational model of human auditory signal processing and perception

    OpenAIRE

    Jepsen, Morten Løve; Ewert, Stephan D.; Dau, Torsten

    2008-01-01

    A model of computational auditory signal-processing and perception that accounts for various aspects of simultaneous and nonsimultaneous masking in human listeners is presented. The model is based on the modulation filterbank model described by Dau et al. [J. Acoust. Soc. Am. 102, 2892 (1997)] but includes major changes at the peripheral and more central stages of processing. The model contains outer- and middle-ear transformations, a nonlinear basilar-membrane processing stage, a hair-cell t...

  6. Building a Shared Definitional Model of Long Duration Human Spaceflight

    Science.gov (United States)

    Arias, Diana; Orr, Martin; Whitmire, Alexandra; Leveton, Lauren; Sandoval, Luis

    2012-01-01

    Objective: To establish the need for a shared definitional model of long duration human spaceflight, that would provide a framework and vision to facilitate communication, research and practice In 1956, on the eve of human space travel, Hubertus Strughold first proposed a "simple classification of the present and future stages of manned flight" that identified key factors, risks and developmental stages for the evolutionary journey ahead. As we look to new destinations, we need a current shared working definitional model of long duration human space flight to help guide our path. Here we describe our preliminary findings and outline potential approaches for the future development of a definition and broader classification system

  7. Humanized in vivo Model for Autoimmune Diabetes

    Science.gov (United States)

    2010-05-07

    guinea - pig polyclonal anti-insulin (1:100 dilution, Abcam Ab7842-500, Cambridge, MA) and a secondary goat anti- guinea - pig Alexa-fluor 568 (1:100 dilu...which is reported to accelerate experimental autoimmune encephalomyelitis (a mouse model of multiple sclerosis). Our reasoning was that, as T cells...HL, Sobel RA, Kuchroo VK. IL-10 is critical in the regulation of autoimmune encephalomyelitis as demonstrated by studies of IL-10- and IL-4

  8. Monte Carlo modeling of human tooth optical coherence tomography imaging

    International Nuclear Information System (INIS)

    Shi, Boya; Meng, Zhuo; Wang, Longzhi; Liu, Tiegen

    2013-01-01

    We present a Monte Carlo model for optical coherence tomography (OCT) imaging of human tooth. The model is implemented by combining the simulation of a Gaussian beam with simulation for photon propagation in a two-layer human tooth model with non-parallel surfaces through a Monte Carlo method. The geometry and the optical parameters of the human tooth model are chosen on the basis of the experimental OCT images. The results show that the simulated OCT images are qualitatively consistent with the experimental ones. Using the model, we demonstrate the following: firstly, two types of photons contribute to the information of morphological features and noise in the OCT image of a human tooth, respectively. Secondly, the critical imaging depth of the tooth model is obtained, and it is found to decrease significantly with increasing mineral loss, simulated as different enamel scattering coefficients. Finally, the best focus position is located below and close to the dental surface by analysis of the effect of focus positions on the OCT signal and critical imaging depth. We anticipate that this modeling will become a powerful and accurate tool for a preliminary numerical study of the OCT technique on diseases of dental hard tissue in human teeth. (paper)

  9. Monte Carlo modeling of human tooth optical coherence tomography imaging

    Science.gov (United States)

    Shi, Boya; Meng, Zhuo; Wang, Longzhi; Liu, Tiegen

    2013-07-01

    We present a Monte Carlo model for optical coherence tomography (OCT) imaging of human tooth. The model is implemented by combining the simulation of a Gaussian beam with simulation for photon propagation in a two-layer human tooth model with non-parallel surfaces through a Monte Carlo method. The geometry and the optical parameters of the human tooth model are chosen on the basis of the experimental OCT images. The results show that the simulated OCT images are qualitatively consistent with the experimental ones. Using the model, we demonstrate the following: firstly, two types of photons contribute to the information of morphological features and noise in the OCT image of a human tooth, respectively. Secondly, the critical imaging depth of the tooth model is obtained, and it is found to decrease significantly with increasing mineral loss, simulated as different enamel scattering coefficients. Finally, the best focus position is located below and close to the dental surface by analysis of the effect of focus positions on the OCT signal and critical imaging depth. We anticipate that this modeling will become a powerful and accurate tool for a preliminary numerical study of the OCT technique on diseases of dental hard tissue in human teeth.

  10. A model for assessing human cognitive reliability in PRA studies

    International Nuclear Information System (INIS)

    Hannaman, G.W.; Spurgin, A.J.; Lukic, Y.

    1985-01-01

    This paper summarizes the status of a research project sponsored by EPRI as part of the Probabilistic Risk Assessment (PRA) technology improvement program and conducted by NUS Corporation to develop a model of Human Cognitive Reliability (HCR). The model was synthesized from features identified in a review of existing models. The model development was based on the hypothesis that the key factors affecting crew response times are separable. The inputs to the model consist of key parameters the values of which can be determined by PRA analysts for each accident situation being assessed. The output is a set of curves which represent the probability of control room crew non-response as a function of time for different conditions affecting their performance. The non-response probability is then a contributor to the overall non-success of operating crews to achieve a functional objective identified in the PRA study. Simulator data and some small scale tests were utilized to illustrate the calibration of interim HCR model coefficients for different types of cognitive processing since the data were sparse. The model can potentially help PRA analysts make human reliability assessments more explicit. The model incorporates concepts from psychological models of human cognitive behavior, information from current collections of human reliability data sources and crew response time data from simulator training exercises

  11. Lumped parametric model of the human ear for sound transmission.

    Science.gov (United States)

    Feng, Bin; Gan, Rong Z

    2004-09-01

    A lumped parametric model of the human auditoria peripherals consisting of six masses suspended with six springs and ten dashpots was proposed. This model will provide the quantitative basis for the construction of a physical model of the human middle ear. The lumped model parameters were first identified using published anatomical data, and then determined through a parameter optimization process. The transfer function of the middle ear obtained from human temporal bone experiments with laser Doppler interferometers was used for creating the target function during the optimization process. It was found that, among 14 spring and dashpot parameters, there were five parameters which had pronounced effects on the dynamic behaviors of the model. The detailed discussion on the sensitivity of those parameters was provided with appropriate applications for sound transmission in the ear. We expect that the methods for characterizing the lumped model of the human ear and the model parameters will be useful for theoretical modeling of the ear function and construction of the ear physical model.

  12. Thresholds and interactive effects of soil moisture on the temperature response of soil respiration

    DEFF Research Database (Denmark)

    Lellei-Kovács, Eszter; Kovács-Láng, Edit; Botta-Dukát, Zoltán

    2011-01-01

    Ecosystem carbon exchange is poorly understood in low-productivity, semiarid habitats. Here we studied the controls of soil temperature and moisture on soil respiration in climate change field experiment in a sandy forest-steppe. Soil CO2 efflux was measured monthly from April to November in 2003......–2008 on plots receiving either rain exclusion or nocturnal warming, or serving as ambient control. Based on this dataset, we developed and compared empirical models of temperature and moisture effects on soil respiration. Results suggest that in this semiarid ecosystem the main controlling factor for soil CO2...... efflux is soil temperature, while soil moisture has less, although significant effect on soil respiration. Clear thresholds for moisture effects on temperature sensitivity were identified at 0.6, 4.0 and 7.0vol% by almost each model, which relate well to other known limits for biological activity...

  13. The Natural Product Osthole Attenuates Yeast Growth by Extensively Suppressing the Gene Expressions of Mitochondrial Respiration Chain.

    Science.gov (United States)

    Wang, Zhe; Shen, Yan

    2017-03-01

    The fast growing evidences have indicated that the natural product osthole is a promising drug candidate for fighting several serious human diseases, for example, cancer and inflammation. However, the mode-of-action (MoA) of osthole remains largely incomplete. In this study, we investigated the growth inhibition activity of osthole using fission yeast as a model, with the goal of understanding the osthole's mechanism of action, especially from the molecular level. Microarray analysis indicated that osthole has significant impacts on gene transcription levels (In total, 214 genes are up-regulated, and 97 genes are down-regulated). Gene set enrichment analysis (GSEA) indicated that 11 genes belong to the "Respiration module" category, especially including the components of complex III and V of mitochondrial respiration chain. Based on GSEA and network analysis, we also found that 54 up-regulated genes belong to the "Core Environmental Stress Responses" category, particularly including many transporter genes, which suggests that the rapidly activated nutrient exchange between cell and environment is part of the MoA of osthole. In summary, osthole can greatly impact on fission yeast transcriptome, and it primarily represses the expression levels of the genes in respiration chain, which next causes the inefficiency of ATP production and thus largely explains osthole's growth inhibition activity in Schizosaccharomyces pombe (S. pombe). The complexity of the osthole's MoA shown in previous studies and our current research demonstrates that the omics approach and bioinformatics tools should be applied together to acquire the complete landscape of osthole's growth inhibition activity.

  14. Modelling the basic error tendencies of human operators

    International Nuclear Information System (INIS)

    Reason, J.

    1988-01-01

    The paper outlines the primary structural features of human cognition: a limited, serial workspace interacting with a parallel distributed knowledge base. It is argued that the essential computational features of human cognition - to be captured by an adequate operator model - reside in the mechanisms by which stored knowledge structures are selected and brought into play. Two such computational 'primitives' are identified: similarity-matching and frequency-gambling. These two retrieval heuristics, it is argued, shape both the overall character of human performance (i.e. its heavy reliance on pattern-matching) and its basic error tendencies ('strong-but-wrong' responses, confirmation, similarity and frequency biases, and cognitive 'lock-up'). The various features of human cognition are integrated with a dynamic operator model capable of being represented in software form. This computer model, when run repeatedly with a variety of problem configurations, should produce a distribution of behaviours which, in total, simulate the general character of operator performance. (author)

  15. Modelling the basic error tendencies of human operators

    International Nuclear Information System (INIS)

    Reason, James

    1988-01-01

    The paper outlines the primary structural features of human cognition: a limited, serial workspace interacting with a parallel distributed knowledge base. It is argued that the essential computational features of human cognition - to be captured by an adequate operator model - reside in the mechanisms by which stored knowledge structures are selected and brought into play. Two such computational 'primitives' are identified: similarity-matching and frequency-gambling. These two retrieval heuristics, it is argued, shape both the overall character of human performance (i.e. its heavy reliance on pattern-matching) and its basic error tendencies ('strong-but-wrong' responses, confirmation, similarity and frequency biases, and cognitive 'lock-up'). The various features of human cognition are integrated with a dynamic operator model capable of being represented in software form. This computer model, when run repeatedly with a variety of problem configurations, should produce a distribution of behaviours which, in toto, simulate the general character of operator performance. (author)

  16. Immunology studies in non-human primate models of tuberculosis.

    Science.gov (United States)

    Flynn, JoAnne L; Gideon, Hannah P; Mattila, Joshua T; Lin, Philana Ling

    2015-03-01

    Non-human primates, primarily macaques, have been used to study tuberculosis for decades. However, in the last 15 years, this model has been refined substantially to allow careful investigations of the immune response and host-pathogen interactions in Mycobacterium tuberculosis infection. Low-dose challenge with fully virulent strains in cynomolgus macaques result in the full clinical spectrum seen in humans, including latent and active infection. Reagents from humans are usually cross-reactive with macaques, further facilitating the use of this model system to study tuberculosis. Finally, macaques develop the spectrum of granuloma types seen in humans, providing a unique opportunity to investigate bacterial and host factors at the local (lung and lymph node) level. Here, we review the past decade of immunology and pathology studies in macaque models of tuberculosis. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  17. Human pluripotent stem cells: an emerging model in developmental biology.

    Science.gov (United States)

    Zhu, Zengrong; Huangfu, Danwei

    2013-02-01

    Developmental biology has long benefited from studies of classic model organisms. Recently, human pluripotent stem cells (hPSCs), including human embryonic stem cells and human induced pluripotent stem cells, have emerged as a new model system that offers unique advantages for developmental studies. Here, we discuss how studies of hPSCs can complement classic approaches using model organisms, and how hPSCs can be used to recapitulate aspects of human embryonic development 'in a dish'. We also summarize some of the recently developed genetic tools that greatly facilitate the interrogation of gene function during hPSC differentiation. With the development of high-throughput screening technologies, hPSCs have the potential to revolutionize gene discovery in mammalian development.

  18. A novel polar-based human face recognition computational model

    Directory of Open Access Journals (Sweden)

    Y. Zana

    2009-07-01

    Full Text Available Motivated by a recently proposed biologically inspired face recognition approach, we investigated the relation between human behavior and a computational model based on Fourier-Bessel (FB spatial patterns. We measured human recognition performance of FB filtered face images using an 8-alternative forced-choice method. Test stimuli were generated by converting the images from the spatial to the FB domain, filtering the resulting coefficients with a band-pass filter, and finally taking the inverse FB transformation of the filtered coefficients. The performance of the computational models was tested using a simulation of the psychophysical experiment. In the FB model, face images were first filtered by simulated V1- type neurons and later analyzed globally for their content of FB components. In general, there was a higher human contrast sensitivity to radially than to angularly filtered images, but both functions peaked at the 11.3-16 frequency interval. The FB-based model presented similar behavior with regard to peak position and relative sensitivity, but had a wider frequency band width and a narrower response range. The response pattern of two alternative models, based on local FB analysis and on raw luminance, strongly diverged from the human behavior patterns. These results suggest that human performance can be constrained by the type of information conveyed by polar patterns, and consequently that humans might use FB-like spatial patterns in face processing.

  19. Modeling aspects of human memory for scientific study.

    Energy Technology Data Exchange (ETDEWEB)

    Caudell, Thomas P. (University of New Mexico); Watson, Patrick (University of Illinois - Champaign-Urbana Beckman Institute); McDaniel, Mark A. (Washington University); Eichenbaum, Howard B. (Boston University); Cohen, Neal J. (University of Illinois - Champaign-Urbana Beckman Institute); Vineyard, Craig Michael; Taylor, Shawn Ellis; Bernard, Michael Lewis; Morrow, James Dan; Verzi, Stephen J.

    2009-10-01

    Working with leading experts in the field of cognitive neuroscience and computational intelligence, SNL has developed a computational architecture that represents neurocognitive mechanisms associated with how humans remember experiences in their past. The architecture represents how knowledge is organized and updated through information from individual experiences (episodes) via the cortical-hippocampal declarative memory system. We compared the simulated behavioral characteristics with those of humans measured under well established experimental standards, controlling for unmodeled aspects of human processing, such as perception. We used this knowledge to create robust simulations of & human memory behaviors that should help move the scientific community closer to understanding how humans remember information. These behaviors were experimentally validated against actual human subjects, which was published. An important outcome of the validation process will be the joining of specific experimental testing procedures from the field of neuroscience with computational representations from the field of cognitive modeling and simulation.

  20. 3D virtual human rapid modeling method based on top-down modeling mechanism

    Directory of Open Access Journals (Sweden)

    LI Taotao

    2017-01-01

    Full Text Available Aiming to satisfy the vast custom-made character demand of 3D virtual human and the rapid modeling in the field of 3D virtual reality, a new virtual human top-down rapid modeling method is put for-ward in this paper based on the systematic analysis of the current situation and shortage of the virtual hu-man modeling technology. After the top-level realization of virtual human hierarchical structure frame de-sign, modular expression of the virtual human and parameter design for each module is achieved gradu-al-level downwards. While the relationship of connectors and mapping restraints among different modules is established, the definition of the size and texture parameter is also completed. Standardized process is meanwhile produced to support and adapt the virtual human top-down rapid modeling practice operation. Finally, the modeling application, which takes a Chinese captain character as an example, is carried out to validate the virtual human rapid modeling method based on top-down modeling mechanism. The result demonstrates high modelling efficiency and provides one new concept for 3D virtual human geometric mod-eling and texture modeling.

  1. Exposure to respirable crystalline silica in South African farm workers

    International Nuclear Information System (INIS)

    Swanepoel, Andrew; Rees, David; Renton, Kevin; Kromhout, Hans

    2009-01-01

    Although listed in some publications as an activity associated with silica (quartz) exposure, agriculture is not widely recognized as an industry with a potential for silica associated diseases. Because so many people work in agriculture; and because silica exposure and silicosis are associated with serious diseases such as tuberculosis (TB), particular in those immunological compromised by the Human immunodeficiency virus (HIV), silica exposure in agriculture is potentially very important. But in South Africa (SA) very little is known about silica exposure in this industry. The objectives of this project are: (a) to measure inhalable and respirable dust and its quartz content on two typical sandy soil farms in the Free State province of SA for all major tasks done on the farms; and (b) to characterise the mineralogy soil type of these farms. Two typical farms in the sandy soil region of the Free State province were studied. The potential health effects faced by these farm workers from exposure to respirable crystalline silica are discussed.

  2. Exposure to respirable crystalline silica in South African farm workers

    Energy Technology Data Exchange (ETDEWEB)

    Swanepoel, Andrew; Rees, David [University of the Witwatersrand, School of Public Health, Johannesburg (South Africa); Renton, Kevin [National Institute for Occupational Health, Johannesburg (South Africa); Kromhout, Hans, E-mail: andrew.swanepoel@wits.ac.z [Environmental Epidemiology Division, Institute for Risk Assessment Sciences, University of Utrecht (Netherlands)

    2009-02-01

    Although listed in some publications as an activity associated with silica (quartz) exposure, agriculture is not widely recognized as an industry with a potential for silica associated diseases. Because so many people work in agriculture; and because silica exposure and silicosis are associated with serious diseases such as tuberculosis (TB), particular in those immunological compromised by the Human immunodeficiency virus (HIV), silica exposure in agriculture is potentially very important. But in South Africa (SA) very little is known about silica exposure in this industry. The objectives of this project are: (a) to measure inhalable and respirable dust and its quartz content on two typical sandy soil farms in the Free State province of SA for all major tasks done on the farms; and (b) to characterise the mineralogy soil type of these farms. Two typical farms in the sandy soil region of the Free State province were studied. The potential health effects faced by these farm workers from exposure to respirable crystalline silica are discussed.

  3. Discrete time modelization of human pilot behavior

    Science.gov (United States)

    Cavalli, D.; Soulatges, D.

    1975-01-01

    This modelization starts from the following hypotheses: pilot's behavior is a time discrete process, he can perform only one task at a time and his operating mode depends on the considered flight subphase. Pilot's behavior was observed using an electro oculometer and a simulator cockpit. A FORTRAN program has been elaborated using two strategies. The first one is a Markovian process in which the successive instrument readings are governed by a matrix of conditional probabilities. In the second one, strategy is an heuristic process and the concepts of mental load and performance are described. The results of the two aspects have been compared with simulation data.

  4. Carbon balance of a subarctic meadow under 3 r{ C warming - unravelling respiration}

    Science.gov (United States)

    Silvennoinen, Hanna; Bárcena, Téresa G.; Moni, Christophe; Szychowski, Marcin; Rajewicz, Paulina; Höglind, Mats; Rasse, Daniel P.

    2016-04-01

    Boreal and arctic terrestrial ecosystems are central to the climate change debate, as the warming is expected to be disproportionate as compared to world averages. Northern areas contain large terrestrial carbon (C) stocks further increasing the interest in the C cycle's fate in changing climate. In 2013, we started an ecosystem warming experiment at a meadow in Eastern Finnmark, NE Norway. The meadow was on a clay soil and its vegetation was common meadow grasses and clover. Typical local agronomy was applied. The study site featured ten 4m-wide hexagonal plots, five control and five actively warmed plots in randomized complete block design. Each of the warmed plots was continuously maintained 3 ° C above its associated control plot with infrared heaters controlled by canopy thermal sensors. In 2014-2015, we measured net ecosystem exchange (NEE) and respiration twice per week during growth seasons from preinstalled collars of each site with dynamic, temperature-controlled chambers combined to an infrared analyzer. Despite warming-induced differences in yield, species composition and root biomass, neither the NEE nor the respiration responded to the warming, all sites remaining equal sinks for C. Following this observation, we carried out an additional experiment in 2015 where we aimed at partitioning the total CO2 flux to microbial and plant respiration as well as at recording the growth season variation of those parameters in situ. Here, we used an approach based on natural abundances of 13C. The δ13C signature of both autotrophic plant respiration and heterotrophic microbial respiration were obtained in targeted incubations (Snell et al. 2014). Then, the δ13C -signature of the total soil respiration was determined in the field by Keeling approach with dynamic dark chambers combined to CRDS. Proportions of autotrophic and heterotrophic components in total soil respiration were then derived based on 13C mixing model. Incubations were repeated at early, mid and

  5. Observations and modeling of deterministic properties of human ...

    Indian Academy of Sciences (India)

    We show that the properties of both models are different from those obtained for Type-I intermittency in the presence of additive noise. The two models help to explain some of the features seen in the intermittency in human heart rate variability. Keywords. Heart rate variability; intermittency; non-stationary dynamical systems.

  6. Comparative homology modeling of human rhodopsin with several ...

    African Journals Online (AJOL)

    The molecular structure of rhodopsin has been studied by cryo-electron microscopic, Nuclear Magnetic Resonance (NMR) and X-ray crystallographic techniques in bovine. A humble effort has been ... Key words: Homology modeling, human rhodopsin, bovine templates, sequence alignment, model building, energy profiles.

  7. Human surrogate models of histaminergic and non-histaminergic itch

    DEFF Research Database (Denmark)

    Andersen, Hjalte Holm; Elberling, Jesper; Arendt-Nielsen, Lars

    2015-01-01

    Within the last decade understanding of the mechanistic basis of itch has improved significantly, resulting in the development of several human surrogate models of itch and related dysesthetic states. Well-characterized somatosensory models are useful in basic studies in healthy volunteers...

  8. Computational 3-D Model of the Human Respiratory System

    Science.gov (United States)

    We are developing a comprehensive, morphologically-realistic computational model of the human respiratory system that can be used to study the inhalation, deposition, and clearance of contaminants, while being adaptable for age, race, gender, and health/disease status. The model ...

  9. Growth Modeling of Human Mandibles using Non-Euclidean Metrics

    DEFF Research Database (Denmark)

    Hilger, Klaus Baggesen; Larsen, Rasmus; Wrobel, Mark

    2003-01-01

    From a set of 31 three-dimensional CT scans we model the temporal shape and size of the human mandible. Each anatomical structure is represented using 14851 semi-landmarks, and mapped into Procrustes tangent space. Exploratory subspace analyses are performed leading to linear models of mandible s...

  10. Child human model development: a hybrid validation approach

    NARCIS (Netherlands)

    Forbes, P.A.; Rooij, L. van; Rodarius, C.; Crandall, J.

    2008-01-01

    The current study presents a development and validation approach of a child human body model that will help understand child impact injuries and improve the biofidelity of child anthropometric test devices. Due to the lack of fundamental child biomechanical data needed to fully develop such models a

  11. Gene therapy in nonhuman primate models of human autoimmune disease

    NARCIS (Netherlands)

    t'Hart, B. A.; Vervoordeldonk, M.; Heeney, J. L.; Tak, P. P.

    2003-01-01

    Before autoimmune diseases in humans can be treated with gene therapy, the safety and efficacy of the used vectors must be tested in valid experimental models. Monkeys, such as the rhesus macaque or the common marmoset, provide such models. This publication reviews the state of the art in monkey

  12. Impact Analysis of a Biomechanical Model of the Human Thorax

    National Research Council Canada - National Science Library

    Jolly, Johannes

    2000-01-01

    .... The objective of the study was to create a viable finite element model of the human thorax. This objective was accomplished through the construction of a three-dimensional finite element model in DYNA3D, a finite element analysis program...

  13. Mathematical Analysis of a Model for Human Immunodeficiency ...

    African Journals Online (AJOL)

    ADOWIE PERE

    ABSTRACT: The objective of this paper is to present a mathematical model formulated to investigate the dynamics of human immunodeficiency virus (HIV). The disease free equilibrium of the model was found to be locally and globally asymptotically stable. The endemic equilibrium point exists and it was discovered that the ...

  14. Numerical human model for impact and seating comfort

    NARCIS (Netherlands)

    Hoof, J.F.A.M. van; Lange, R. de; Verver, M.M.

    2003-01-01

    This paper presents a detailed numerical model of the human body that can be used to evaluate both safety and comfort aspects of vehicle interiors. The model is based on a combination of rigid body and finite element techniques to provide an optimal combination of computational efficiency and

  15. Establishment and characterization of a reconstructed Chinese human epidermis model.

    Science.gov (United States)

    Qiu, J; Zhong, L; Zhou, M; Chen, D; Huang, X; Chen, J; Chen, M; Ni, H; Cai, Z

    2016-02-01

    In vitro reconstructed human epidermis is a powerful tool for both basic research and industrial applications in dermatology, pharmacology and the cosmetic field. By growing keratinocytes of Chinese origin on a collagen matrix after a submerged culture followed by an air-liquid interface culture, an in vitro reconstructed Chinese human epidermis model was obtained. This Chinese epidermis model was further characterized. The reconstructed human epidermis model (China EpiSkin model) exhibits morphological features similar to native skin and shows similar expression profile of proliferation (Ki67) and differentiation (K14 and K10 cytokeratins, filaggrin) markers. Corneodesmosomes, lamellar lipids, desmosomes, keratohyalin granules, keratin filaments and membrane-coating granules are also observed at the ultrastructure level. Moreover, China EpiSkin model contains most of the major lipid classes normally found in the native skin and potentially could present the properties of skin barrier. More importantly, the model production achieves high reproducibility and low intra- and inter-batch variations. This is the first reconstructed Chinese human epidermis model reported to meet the high quality standard with industrialized production criteria. This China EpiSkin model can be used for both skin research and safety assessment in vitro. © 2015 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  16. A Systemic Cause Analysis Model for Human Performance Technicians

    Science.gov (United States)

    Sostrin, Jesse

    2011-01-01

    This article presents a systemic, research-based cause analysis model for use in the field of human performance technology (HPT). The model organizes the most prominent barriers to workplace learning and performance into a conceptual framework that explains and illuminates the architecture of these barriers that exist within the fabric of everyday…

  17. Human strategic reasoning in dynamic games: Experiments, logics, cognitive models

    NARCIS (Netherlands)

    Ghosh, Sujata; Halder, Tamoghna; Sharma, Khyati; Verbrugge, Rineke

    2015-01-01

    © Springer-Verlag Berlin Heidelberg 2015.This article provides a three-way interaction between experiments, logic and cognitive modelling so as to bring out a shared perspective among these diverse areas, aiming towards better understanding and better modelling of human strategic reasoning in

  18. Meeting Human Reliability Requirements through Human Factors Design, Testing, and Modeling

    Energy Technology Data Exchange (ETDEWEB)

    R. L. Boring

    2007-06-01

    In the design of novel systems, it is important for the human factors engineer to work in parallel with the human reliability analyst to arrive at the safest achievable design that meets design team safety goals and certification or regulatory requirements. This paper introduces the System Development Safety Triptych, a checklist of considerations for the interplay of human factors and human reliability through design, testing, and modeling in product development. This paper also explores three phases of safe system development, corresponding to the conception, design, and implementation of a system.

  19. Quantitative Modeling of Human-Environment Interactions in Preindustrial Time

    Science.gov (United States)

    Sommer, Philipp S.; Kaplan, Jed O.

    2017-04-01

    Quantifying human-environment interactions and anthropogenic influences on the environment prior to the Industrial revolution is essential for understanding the current state of the earth system. This is particularly true for the terrestrial biosphere, but marine ecosystems and even climate were likely modified by human activities centuries to millennia ago. Direct observations are however very sparse in space and time, especially as one considers prehistory. Numerical models are therefore essential to produce a continuous picture of human-environment interactions in the past. Agent-based approaches, while widely applied to quantifying human influence on the environment in localized studies, are unsuitable for global spatial domains and Holocene timescales because of computational demands and large parameter uncertainty. Here we outline a new paradigm for the quantitative modeling of human-environment interactions in preindustrial time that is adapted to the global Holocene. Rather than attempting to simulate agency directly, the model is informed by a suite of characteristics describing those things about society that cannot be predicted on the basis of environment, e.g., diet, presence of agriculture, or range of animals exploited. These categorical data are combined with the properties of the physical environment in coupled human-environment model. The model is, at its core, a dynamic global vegetation model with a module for simulating crop growth that is adapted for preindustrial agriculture. This allows us to simulate yield and calories for feeding both humans and their domesticated animals. We couple this basic caloric availability with a simple demographic model to calculate potential population, and, constrained by labor requirements and land limitations, we create scenarios of land use and land cover on a moderate-resolution grid. We further implement a feedback loop where anthropogenic activities lead to changes in the properties of the physical

  20. Oxygen dependence of respiration in rat spinotrapezius muscle in situ.

    Science.gov (United States)

    Golub, Aleksander S; Pittman, Roland N

    2012-07-01

    The oxygen dependence of respiration in striated muscle in situ was studied by measuring the rate of decrease of interstitial Po(2) [oxygen disappearance curve (ODC)] following rapid arrest of blood flow by pneumatic tissue compression, which ejected red blood cells from the muscle vessels and made the ODC independent from oxygen bound to hemoglobin. After the contribution of photo-consumption of oxygen by the method was evaluated and accounted for, the corrected ODCs were converted into the Po(2) dependence of oxygen consumption, Vo(2), proportional to the rate of Po(2) decrease. Fitting equations obtained from a model of heterogeneous intracellular Po(2) were applied to recover the parameters describing respiration in muscle fibers, with a predicted sigmoidal shape for the dependence of Vo(2) on Po(2). This curve consists of two regions connected by the point for critical Po(2) of the cell (i.e., Po(2) at the sarcolemma when the center of the cell becomes anoxic). The critical Po(2) was below the Po(2) for half-maximal respiratory rate (P(50)) for the cells. In six muscles at rest, the rate of oxygen consumption was 139 ± 6 nl O(2)/cm(3)·s and mitochondrial P(50) was k = 10.5 ± 0.8 mmHg. The range of Po(2) values inside the muscle fibers was found to be 4-5 mmHg at the critical Po(2). The oxygen dependence of respiration can be studied in thin muscles under different experimental conditions. In resting muscle, the critical Po(2) was substantially lower than the interstitial Po(2) of 53 ± 2 mmHg, a finding that indicates that Vo(2) under this circumstance is independent of oxygen supply and is discordant with the conventional hypothesis of metabolic regulation of the oxygen supply to tissue.

  1. Oxygen dependence of respiration in rat spinotrapezius muscle in situ

    Science.gov (United States)

    Pittman, Roland N.

    2012-01-01

    The oxygen dependence of respiration in striated muscle in situ was studied by measuring the rate of decrease of interstitial Po2 [oxygen disappearance curve (ODC)] following rapid arrest of blood flow by pneumatic tissue compression, which ejected red blood cells from the muscle vessels and made the ODC independent from oxygen bound to hemoglobin. After the contribution of photo-consumption of oxygen by the method was evaluated and accounted for, the corrected ODCs were converted into the Po2 dependence of oxygen consumption, V̇o2, proportional to the rate of Po2 decrease. Fitting equations obtained from a model of heterogeneous intracellular Po2 were applied to recover the parameters describing respiration in muscle fibers, with a predicted sigmoidal shape for the dependence of V̇o2 on Po2. This curve consists of two regions connected by the point for critical Po2 of the cell (i.e., Po2 at the sarcolemma when the center of the cell becomes anoxic). The critical Po2 was below the Po2 for half-maximal respiratory rate (P50) for the cells. In six muscles at rest, the rate of oxygen consumption was 139 ± 6 nl O2/cm3·s and mitochondrial P50 was k = 10.5 ± 0.8 mmHg. The range of Po2 values inside the muscle fibers was found to be 4–5 mmHg at the critical Po2. The oxygen dependence of respiration can be studied in thin muscles under different experimental conditions. In resting muscle, the critical Po2 was substantially lower than the interstitial Po2 of 53 ± 2 mmHg, a finding that indicates that V̇o2 under this circumstance is independent of oxygen supply and is discordant with the conventional hypothesis of metabolic regulation of the oxygen supply to tissue. PMID:22523254

  2. Temporal and Spatial Distribution of Respirable Dust After Blasting of Coal Roadway Driving Faces: A Case Study

    Directory of Open Access Journals (Sweden)

    Shengyong Hu

    2015-10-01

    Full Text Available Coal roadway driving is an important part of the underground mining system, and very common in Chinese coal mines. However, the high concentration of respirable dust produced in the blasting operation poses a great hazard to miners’ health as well as the underground environment. In this paper, based on the direct simulation Monte Carlo method, the gas–solid two-phase flow model of particle movement is established to study the respirable dust distribution in blasting driving face. The results show that there is an obvious vortex region in which airflow velocity is lower than that close to the roadway wall and driving face. After blasting, respirable dust in the front of the dust group jet from the driving face cannot be discharged timely, with the result that its concentration is higher than the critical value until it is expelled from the roadway, whereas respirable dust concentration at the back of the dust group is gradually diluted and exhibits an alternate thin dense phase distribution. Meanwhile, respirable dust concentration in the breathing zone is relatively higher than that at the top and bottom of roadway. The accuracy of numerical simulation results is verified by field measurements. The research results are helpful for further understanding the evolution of respirable dust distribution after blasting, and are good for providing guidance for efficient controlling of respirable dust and improving the working environment for underground miners.

  3. Geometry Modeling Program Implementation of Human Hip Tissue

    Directory of Open Access Journals (Sweden)

    WANG Mo-nan

    2017-10-01

    Full Text Available Abstract:Aiming to design a simulate software of human tissue modeling and analysis,Visual Studio 2010 is selected as a development tool to develop a 3 D reconstruction software of human tissue with language C++.It can be used alone. It also can be a module of the virtual surgery systems. The system includes medical image segmentation modules and 3 D reconstruction modules,and can realize the model visualization. This software system has been used to reconstruct hip muscles,femur and hip bone accurately. The results show these geometry models can simulate the structure of hip tissues.

  4. Geometry Modeling Program Implementation of Human Hip Tissue

    Directory of Open Access Journals (Sweden)

    WANG Monan

    2017-04-01

    Full Text Available Aiming to design a simulate software of human tissue modeling and analysis,Visual Studio 2010 is selected as a development tool to develop a 3 D reconstruction software of human tissue with language C++.It can be used alone. It also can be a module of the virtual surgery systems. The system includes medical image segmentation modules and 3 D reconstruction modules,and can realize the model visualization. This software system has been used to reconstruct hip muscles,femur and hip bone accurately. The results show these geometry models can simulate the structure of hip tissues.

  5. Modeling Human Behavior to Anticipate Insider Attacks

    Directory of Open Access Journals (Sweden)

    Ryan E Hohimer

    2011-01-01

    Full Text Available The insider threat ranks among the most pressing cyber-security challenges that threaten government and industry information infrastructures. To date, no systematic methods have been developed that provide a complete and effective approach to prevent data leakage, espionage, and sabotage. Current practice is forensic in nature, relegating to the analyst the bulk of the responsibility to monitor, analyze, and correlate an overwhelming amount of data. We describe a predictive modeling framework that integrates a diverse set of data sources from the cyber domain, as well as inferred psychological/motivational factors that may underlie malicious insider exploits. This comprehensive threat assessment approach provides automated support for the detection of high-risk behavioral "triggers" to help focus the analyst's attention and inform the analysis. Designed to be domain-independent, the system may be applied to many different threat and warning analysis/sense-making problems.

  6. MODELING ENERGY EXPENDITURE AND OXYGEN CONSUMPTION IN HUMAN EXPOSURE MODELS: ACCOUNTING FOR FATIGUE AND EPOC

    Science.gov (United States)

    Human exposure and dose models often require a quantification of oxygen consumption for a simulated individual. Oxygen consumption is dependent on the modeled Individual's physical activity level as described in an activity diary. Activity level is quantified via standardized val...

  7. Integrating modelling and smart sensors for environmental and human health.

    Science.gov (United States)

    Reis, Stefan; Seto, Edmund; Northcross, Amanda; Quinn, Nigel W T; Convertino, Matteo; Jones, Rod L; Maier, Holger R; Schlink, Uwe; Steinle, Susanne; Vieno, Massimo; Wimberly, Michael C

    2015-12-01

    Sensors are becoming ubiquitous in everyday life, generating data at an unprecedented rate and scale. However, models that assess impacts of human activities on environmental and human health, have typically been developed in contexts where data scarcity is the norm. Models are essential tools to understand processes, identify relationships, associations and causality, formalize stakeholder mental models, and to quantify the effects of prevention and interventions. They can help to explain data, as well as inform the deployment and location of sensors by identifying hotspots and areas of interest where data collection may achieve the best results. We identify a paradigm shift in how the integration of models and sensors can contribute to harnessing 'Big Data' and, more importantly, make the vital step from 'Big Data' to 'Big Information'. In this paper, we illustrate current developments and identify key research needs using human and environmental health challenges as an example.

  8. Use of electromyography measurement in human body modeling

    Directory of Open Access Journals (Sweden)

    Valdmanová L.

    2011-06-01

    Full Text Available The aim of this study is to test the use of the human body model for the muscle activity computation. This paper shows the comparison of measured and simulated muscle activities. Muscle active states of biceps brachia muscle are monitored by method called electromyography (EMG in a given position and for given subsequently increasing loads. The same conditions are used for simulation using a human body model (Hynčík, L., Rigid Body Based Human Model for Crash Test Purposes, EngineeringMechanics, 5 (8 (2001 1–6. This model consists of rigid body segments connected by kinematic joints and involves all major muscle bunches. Biceps brachia active states are evaluated by a special muscle balance solver. Obtained simulation results show the acceptable correlation with the experimental results. The analysis shows that the validation procedure of muscle activities determination is usable.

  9. A Systems Model for Teaching Human Resource Management

    Directory of Open Access Journals (Sweden)

    George R. Greene

    2013-07-01

    Full Text Available Efficient and effective human resource management is a complex, involved, and interactive process. This article presents and discusses a unique systems approach model for teaching human resource (people management processes, and the important inter-relationships within that process. The model contains two unique components related to key sub-processes: incentives management and performance evaluation. We have not observed a model applying a systems thinking paradigm presented in any textbook, journal article, business publication, or other literature addressing the topic. For nearly three decades, the model has been used in teaching a comprehensive, meaningful understanding of the human resource management process that can be effectively implemented in both corporate and academic learning venues.

  10. A comparative study of seven human cochlear filter models.

    Science.gov (United States)

    Saremi, Amin; Beutelmann, Rainer; Dietz, Mathias; Ashida, Go; Kretzberg, Jutta; Verhulst, Sarah

    2016-09-01

    Auditory models have been developed for decades to simulate characteristics of the human auditory system, but it is often unknown how well auditory models compare to each other or perform in tasks they were not primarily designed for. This study systematically analyzes predictions of seven publicly-available cochlear filter models in response to a fixed set of stimuli to assess their capabilities of reproducing key aspects of human cochlear mechanics. The following features were assessed at frequencies of 0.5, 1, 2, 4, and 8 kHz: cochlear excitation patterns, nonlinear response growth, frequency selectivity, group delays, signal-in-noise processing, and amplitude modulation representation. For each task, the simulations were compared to available physiological data recorded in guinea pigs and gerbils as well as to human psychoacoustics data. The presented results provide application-oriented users with comprehensive information on the advantages, limitations and computation costs of these seven mainstream cochlear filter models.

  11. Modelling human myoblasts survival upon xenotransplantation into immunodeficient mouse muscle.

    Science.gov (United States)

    Praud, Christophe; Vauchez, Karine; Zongo, Pascal; Vilquin, Jean-Thomas

    2018-03-15

    Cell transplantation has been challenged in several clinical indications of genetic or acquired muscular diseases, but therapeutic success were mitigated. To understand and improve the yields of tissue regeneration, we aimed at modelling the fate of CD56-positive human myoblasts after transplantation. Using immunodeficient severe combined immunodeficiency (SCID) mice as recipients, we assessed the survival, integration and satellite cell niche occupancy of human myoblasts by a triple immunohistochemical labelling of laminin, dystrophin and human lamin A/C. The counts were integrated into a classical mathematical decline equation. After injection, human cells were essentially located in the endomysium, then they disappeared progressively from D0 to D28. The final number of integrated human nuclei was grossly determined at D2 after injection, suggesting that no more efficient fusion between donor myoblasts and host fibers occurs after the resolution of the local damages created by needle insertion. Almost 1% of implanted human cells occupied a satellite-like cell niche. Our mathematical model validated by histological counting provided a reliable quantitative estimate of human myoblast survival and/or incorporation into SCID muscle fibers. Informations brought by histological labelling and this mathematical model are complementary. Copyright © 2018 Elsevier Inc. All rights reserved.

  12. Did Respiration or Photosynthesis Come First

    International Nuclear Information System (INIS)

    Broda, E.

    1979-01-01

    The similarity of the mechanisms in photosynthetic and in oxidative phosphorylation suggests a common origin ( convers ion hypothesis). It is proposed that an early form of electron flow with oxidative phosphorylation ( p rerespiration ) , to terminal electron acceptors available in a reducing biosphere, was supplemented by a photocatalyst capable of a redox reaction. In this way, cyclic photophosphorylation arose. Further stages in evolution were reverse electron flow powered by ATP, to make NADH as a reductant for CO2 , and subsequently noncyclic electron flow. These processes concomitantly provided the oxidants indispensable for full development of oxidative phosphorylation, i.e. for normal respiration: sulphate, O2 and with participation of the nitrificants, nitrite and nitrate. Thus, prerespiration preceded photosynthesis, and this preceded respiration. It is also suggested that nonredox photoprocesses of the Halobacterium type are not part of the mainstream of bioenergetic evolution. They do not lead to photoprocesses with electron flow. (author)

  13. Modeling and simulating human teamwork behaviors using intelligent agents

    Science.gov (United States)

    Fan, Xiaocong; Yen, John

    2004-12-01

    Among researchers in multi-agent systems there has been growing interest in using intelligent agents to model and simulate human teamwork behaviors. Teamwork modeling is important for training humans in gaining collaborative skills, for supporting humans in making critical decisions by proactively gathering, fusing, and sharing information, and for building coherent teams with both humans and agents working effectively on intelligence-intensive problems. Teamwork modeling is also challenging because the research has spanned diverse disciplines from business management to cognitive science, human discourse, and distributed artificial intelligence. This article presents an extensive, but not exhaustive, list of work in the field, where the taxonomy is organized along two main dimensions: team social structure and social behaviors. Along the dimension of social structure, we consider agent-only teams and mixed human-agent teams. Along the dimension of social behaviors, we consider collaborative behaviors, communicative behaviors, helping behaviors, and the underpinning of effective teamwork-shared mental models. The contribution of this article is that it presents an organizational framework for analyzing a variety of teamwork simulation systems and for further studying simulated teamwork behaviors.

  14. Development of a finite element model of the human abdomen.

    Science.gov (United States)

    Lee, J B; Yang, K H

    2001-11-01

    Currently, three-dimensional finite element models of the human body have been developed for frequently injured anatomical regions such as the brain, chest, extremities and pelvis. While a few models of the human body include the abdomen, these models have tended to oversimplify the complexity of the abdominal region. As the first step in understanding abdominal injuries via numerical methods, a 3D finite element model of a 50(th) percentile male human abdomen (WSUHAM) has been developed and validated against experimental data obtained from two sets of side impact tests and a series of frontal impact tests. The model includes a detailed representation of the liver, spleen, kidneys, spine, skin and major blood vessels. Hollow organs, such as the esophagus, stomach, small and large intestines, gallbladder, bile ducts, ureters, rectum and adrenal glands are grouped into three bodybags in order to provide realistic inertial properties and to maintain the position of the solid organs in their appropriate locations. Using direct connections, the model was joined superiorly to a partial model of the human thorax, and inferiorly to models of the human pelvis and the lower extremities that have been previously developed. Material properties for various tissues of the abdomen were derived from the literature. Data obtained in a series of cadaveric pendulum impact tests conducted at Wayne State University (WSU), a series of lateral drop tests conducted at Association Peugeot-Renault (APR) and a series of cadaveric lower abdomen frontal impact tests conducted at WSU were used to validate the model. Results predicted by the model match these experimental data for various impact speeds, impactor masses and drop heights. Further study is still needed in order to fully validate WSUHAM before it can be used to assess various impact loading conditions associated with vehicular crashes.

  15. Study of Optical Models Regarding the Human Eye

    Directory of Open Access Journals (Sweden)

    Maryam Abolmasoomi

    2011-03-01

    Full Text Available Introduction: Until now, many models have been presented for optical study of the human eye. In recent years, surgery on the anterior section of the eye (such as cataract and photo-refractive surgery has increased, so a study on the optics of the eye and evaluation of vision quality has become more important. Material and Methods: In this article, some of these models are considered. They include models with spherical and conic-section surfaces (for cornea and lens, simple models and new models with complex surfaces. Results: Evaluation of the optical models of the eye provides the possibility of enhancing the representation of human vision and also increasing the accuracy of surgery on the anterior section of the eye to enable higher quality vision.

  16. Human tumor infiltrating lymphocytes cooperatively regulate prostate tumor growth in a humanized mouse model.

    Science.gov (United States)

    Roth, Michael D; Harui, Airi

    2015-01-01

    The complex interactions that occur between human tumors, tumor infiltrating lymphocytes (TIL) and the systemic immune system are likely to define critical factors in the host response to cancer. While conventional animal models have identified an array of potential anti-tumor therapies, mouse models often fail to translate into effective human treatments. Our goal is to establish a humanized tumor model as a more effective pre-clinical platform for understanding and manipulating TIL. The immune system in NOD/SCID/IL-2Rγnull (NSG) mice was reconstituted by the co-administration of human peripheral blood lymphocytes (PBL) or subsets (CD4+ or CD8+) and autologous human dendritic cells (DC), and animals simultaneously challenged by implanting human prostate cancer cells (PC3 line). Tumor growth was evaluated over time and the phenotype of recovered splenocytes and TIL characterized by flow cytometry and immunohistochemistry (IHC). Serum levels of circulating cytokines and chemokines were also assessed. A tumor-bearing huPBL-NSG model was established in which human leukocytes reconstituted secondary lymphoid organs and promoted the accumulation of TIL. These TIL exhibited a unique phenotype when compared to splenocytes with a predominance of CD8+ T cells that exhibited increased expression of CD69, CD56, and an effector memory phenotype. TIL from huPBL-NSG animals closely matched the features of TIL recovered from primary human prostate cancers. Human cytokines were readily detectible in the serum and exhibited a different profile in animals implanted with PBL alone, tumor alone, and those reconstituted with both. Immune reconstitution slowed but could not eliminate tumor growth and this effect required the presence of CD4+ T cell help. Simultaneous implantation of human PBL, DC and tumor results in a huPBL-NSG model that recapitulates the development of human TIL and allows an assessment of tumor and immune system interaction that cannot be carried out in humans

  17. Modeling cognition and disease using human glial chimeric mice.

    Science.gov (United States)

    Goldman, Steven A; Nedergaard, Maiken; Windrem, Martha S

    2015-08-01

    As new methods for producing and isolating human glial progenitor cells (hGPCs) have been developed, the disorders of myelin have become especially compelling targets for cell-based therapy. Yet as animal modeling of glial progenitor cell-based therapies has progressed, it has become clear that transplanted hGPCs not only engraft and expand within murine hosts, but dynamically outcompete the resident progenitors so as to ultimately dominate the host brain. The engrafted human progenitor cells proceed to generate parenchymal astrocytes, and when faced with a hypomyelinated environment, oligodendrocytes as well. As a result, the recipient brains may become inexorably humanized with regards to their resident glial populations, yielding human glial chimeric mouse brains. These brains provide us a fundamentally new tool by which to assess the species-specific attributes of glia in modulating human cognition and information processing. In addition, the cellular humanization of these brains permits their use in studying glial infectious and inflammatory disorders unique to humans, and the effects of those disorders on the glial contributions to cognition. Perhaps most intriguingly, by pairing our ability to construct human glial chimeras with the production of patient-specific hGPCs derived from pluripotential stem cells, we may now establish mice in which a substantial proportion of resident glia are both human and disease-derived. These mice in particular may provide us new opportunities for studying the human-specific contributions of glia to psychopathology, as well as to higher cognition. As such, the assessment of human glial chimeric mice may provide us new insight into the species-specific contributions of glia to human cognitive evolution, as well as to the pathogenesis of human neurological and neuropsychiatric disease. © 2015 Wiley Periodicals, Inc.

  18. Mitochondrial respiration in hummingbird flight muscles.

    OpenAIRE

    Suarez, R K; Lighton, J R; Brown, G S; Mathieu-Costello, O

    1991-01-01

    Respiration rates of muscle mitochondria in flying hummingbirds range from 7 to 10 ml of O2 per cm3 of mitochondria per min, which is about 2 times higher than the range obtained in the locomotory muscles of mammals running at their maximum aerobic capacities (VO2max). Capillary volume density is higher in hummingbird flight muscles than in mammalian skeletal muscles. Mitochondria occupy approximately 35% of fiber volume in hummingbird flight muscles and cluster beneath the sarcolemmal membra...

  19. Carbon dioxide fixation and respiration relationships observed during closure experiments in Biosphere 2

    Science.gov (United States)

    Nelson, Mark; Dempster, William; Allen, John P.

    Biosphere 2 enclosed several ecosystems - ones analogous to rainforest, tropical savannah, thornscrub, desert, marsh and coral reef - and a diverse agro-ecology, with dozens of food crops, in virtual material isolation from Earth's environment. This permits a detailed examination of fixation and respiration from the continuous record of carbon dioxide concentration from sensors inside the facility. Unlike the Earth, all the ecosystems were active during sunlight hours, while phyto and soil respiration dominated nighttime hours. This resulted in fluctuations of as much as 600-700 ppm CO2 daily during days of high sunlight input. We examine the relationships between daytime fixation as driven by photosynthesis to nighttime respiration and also fixation and respiration as related to carbon dioxide concentration. Since carbon dioxide concentrations varied from near Earth ambient levels to over 3000 ppm (during low-light winter months), the response of the plant communities and impact on phytorespiration and soil respiration may be of relevance to the global climate change research community. An investigation of these dynamics will also allow the testing of models predicting the response of community metabolism to variations in sunlight and degree of previous net carbon fixation.

  20. Submaximal ADP-stimulated respiration is impaired in ZDF rats and recovered by resveratrol.

    Science.gov (United States)

    Smith, Brennan K; Perry, Christopher G R; Herbst, Eric A F; Ritchie, Ian R; Beaudoin, Marie-Soleil; Smith, Jeffrey C; Neufer, P Darrell; Wright, David C; Holloway, Graham P

    2013-12-01

    Mitochondrial dysfunction and reactive oxygen species (ROS) have been implicated in the aetiology of skeletal muscle insulin resistance, although there is considerable controversy regarding these concepts. Mitochondrial function has been traditionally assessed in the presence of saturating ADP, but ATP turnover and the resultant ADP is thought to limit respiration in vivo. Therefore, we investigated the potential link between submaximal ADP-stimulated respiration rates, ROS generation and skeletal muscle insulin sensitivity in a model of type 2 diabetes mellitus, the ZDF rat. Utilizing permeabilized muscle fibres we observed that submaximal ADP-stimulated respiration rates (250-2000 μm ADP) were lower in ZDF rats than in lean controls, which coincided with decreased adenine nucleotide translocase 2 (ANT2) protein content. This decrease in submaximal ADP-stimulated respiration occurred in the absence of a decrease in electron transport chain function. Treating ZDF rats with resveratrol improved skeletal muscle insulin resistance and this was associated with elevated submaximal ADP-stimulated respiration rates as well as an increase in ANT2 protein content. These results coincided with a greater ability of ADP to attenuate mitochondrial ROS emission and an improvement in cellular redox balance. Together, these data suggest that mitochondrial dysfunction is present in skeletal muscle insulin resistance when assessed at submaximal ADP concentrations and that ADP dynamics may influence skeletal muscle insulin sensitivity through alterations in the propensity for mitochondrial ROS emission.

  1. Temperature sensitivity of soil respiration rates enhanced by microbial community response.

    Science.gov (United States)

    Karhu, Kristiina; Auffret, Marc D; Dungait, Jennifer A J; Hopkins, David W; Prosser, James I; Singh, Brajesh K; Subke, Jens-Arne; Wookey, Philip A; Agren, Göran I; Sebastià, Maria-Teresa; Gouriveau, Fabrice; Bergkvist, Göran; Meir, Patrick; Nottingham, Andrew T; Salinas, Norma; Hartley, Iain P

    2014-09-04

    Soils store about four times as much carbon as plant biomass, and soil microbial respiration releases about 60 petagrams of carbon per year to the atmosphere as carbon dioxide. Short-term experiments have shown that soil microbial respiration increases exponentially with temperature. This information has been incorporated into soil carbon and Earth-system models, which suggest that warming-induced increases in carbon dioxide release from soils represent an important positive feedback loop that could influence twenty-first-century climate change. The magnitude of this feedback remains uncertain, however, not least because the response of soil microbial communities to changing temperatures has the potential to either decrease or increase warming-induced carbon losses substantially. Here we collect soils from different ecosystems along a climate gradient from the Arctic to the Amazon and investigate how microbial community-level responses control the temperature sensitivity of soil respiration. We find that the microbial community-level response more often enhances than reduces the mid- to long-term (90 days) temperature sensitivity of respiration. Furthermore, the strongest enhancing responses were observed in soils with high carbon-to-nitrogen ratios and in soils from cold climatic regions. After 90 days, microbial community responses increased the temperature sensitivity of respiration in high-latitude soils by a factor of 1.4 compared to the instantaneous temperature response. This suggests that the substantial carbon stores in Arctic and boreal soils could be more vulnerable to climate warming than currently predicted.

  2. A new role-model for the future humanities?

    DEFF Research Database (Denmark)

    Caviglia, Francesco; Pedersen, Alex Young

    of citizens” who work together to design solutions for living better together, which the authors suggest being an equally productive role-model as the idea of a “scientific research groups and industrial design teams”, which is the standard role-model for KB prac-tice. The authors sees this alternative model...... as an important contribution and supplement for the future Humanities in the university....

  3. Modeling Human Behaviour with Higher Order Logic: Insider Threats

    DEFF Research Database (Denmark)

    Boender, Jaap; Ivanova, Marieta Georgieva; Kammuller, Florian

    2014-01-01

    it to the sociological process of logical explanation. As a case study on modeling human behaviour, we present the modeling and analysis of insider threats as a Higher Order Logic theory in Isabelle/HOL. We show how each of the three step process of sociological explanation can be seen in our modeling of insider’s state......, its context within an organisation and the effects on security as outcomes of a theorem proving analysis....

  4. Microscopic modelling circadian and bursty pattern of human activities.

    Directory of Open Access Journals (Sweden)

    Jinhong Kim

    Full Text Available Recent studies for a wide range of human activities such as email communication, Web browsing, and library visiting, have revealed the bursty nature of human activities. The distribution of inter-event times (IETs between two consecutive human activities exhibits a heavy-tailed decay behavior and the oscillating pattern with a one-day period, reflective of the circadian pattern of human life. Even though a priority-based queueing model was successful as a basic model for understanding the heavy-tailed behavior, it ignored important ingredients, such as the diversity of individual activities and the circadian pattern of human life. Here, we collect a large scale of dataset which contains individuals' time stamps when articles are posted on blog posts, and based on which we construct a theoretical model which can take into account of both ignored ingredients. Once we identify active and inactive time intervals of individuals and remove the inactive time interval, thereby constructing an ad hoc continuous time domain. Therein, the priority-based queueing model is applied by adjusting the arrival and the execution rates of tasks by comparing them with the activity data of individuals. Then, the obtained results are transferred back to the real-time domain, which produces the oscillating and heavy-tailed IET distribution. This microscopic model enables us to develop theoretical understanding towards more empirical results.

  5. Microscopic modelling circadian and bursty pattern of human activities.

    Science.gov (United States)

    Kim, Jinhong; Lee, Deokjae; Kahng, Byungnam

    2013-01-01

    Recent studies for a wide range of human activities such as email communication, Web browsing, and library visiting, have revealed the bursty nature of human activities. The distribution of inter-event times (IETs) between two consecutive human activities exhibits a heavy-tailed decay behavior and the oscillating pattern with a one-day period, reflective of the circadian pattern of human life. Even though a priority-based queueing model was successful as a basic model for understanding the heavy-tailed behavior, it ignored important ingredients, such as the diversity of individual activities and the circadian pattern of human life. Here, we collect a large scale of dataset which contains individuals' time stamps when articles are posted on blog posts, and based on which we construct a theoretical model which can take into account of both ignored ingredients. Once we identify active and inactive time intervals of individuals and remove the inactive time interval, thereby constructing an ad hoc continuous time domain. Therein, the priority-based queueing model is applied by adjusting the arrival and the execution rates of tasks by comparing them with the activity data of individuals. Then, the obtained results are transferred back to the real-time domain, which produces the oscillating and heavy-tailed IET distribution. This microscopic model enables us to develop theoretical understanding towards more empirical results.

  6. DigitalHuman (DH): An Integrative Mathematical Model ofHuman Physiology

    Science.gov (United States)

    Hester, Robert L.; Summers, Richard L.; lIescu, Radu; Esters, Joyee; Coleman, Thomas G.

    2010-01-01

    Mathematical models and simulation are important tools in discovering the key causal relationships governing physiological processes and improving medical intervention when physiological complexity is a central issue. We have developed a model of integrative human physiology called DigitalHuman (DH) consisting of -5000 variables modeling human physiology describing cardiovascular, renal, respiratory, endocrine, neural and metabolic physiology. Users can view time-dependent solutions and interactively introduce perturbations by altering numerical parameters to investigate new hypotheses. The variables, parameters and quantitative relationships as well as all other model details are described in XML text files. All aspects of the model, including the mathematical equations describing the physiological processes are written in XML open source, text-readable files. Model structure is based upon empirical data of physiological responses documented within the peer-reviewed literature. The model can be used to understand proposed physiological mechanisms and physiological interactions that may not be otherwise intUitively evident. Some of the current uses of this model include the analyses of renal control of blood pressure, the central role of the liver in creating and maintaining insulin resistance, and the mechanisms causing orthostatic hypotension in astronauts. Additionally the open source aspect of the modeling environment allows any investigator to add detailed descriptions of human physiology to test new concepts. The model accurately predicts both qualitative and more importantly quantitative changes in clinically and experimentally observed responses. DigitalHuman provides scientists a modeling environment to understand the complex interactions of integrative physiology. This research was supported by.NIH HL 51971, NSF EPSCoR, and NASA

  7. 2002 Defense Modeling and Simulation Office (DMSO) Laboratory for Human Behavior Model Interchange Standards

    Science.gov (United States)

    2003-07-01

    among Human Behavior Modeling (HEM) -related models in the Department of Defense (DoD), Industry, Academia, and other Government simulations by...establishing a Laboratory for the Study of Human Behavior Representation Interchange Standard. With experience, expertise, and technologies of the

  8. A Budyko-type Model for Human Water Consumption

    Science.gov (United States)

    Lei, X.; Zhao, J.; Wang, D.; Sivapalan, M.

    2017-12-01

    With the expansion of human water footprint, water crisis is no longer only a conflict or competition for water between different economic sectors, but also increasingly between human and the environment. In order to describe the emergent dynamics and patterns of the interaction, a theoretical framework that encapsulates the physical and societal controls impacting human water consumption is needed. In traditional hydrology, Budyko-type models are simple but efficient descriptions of vegetation-mediated hydrologic cycle in catchments, i.e., the partitioning of mean annual precipitation into runoff and evapotranspiration. Plant water consumption plays a crucial role in the process. Hypothesized similarities between human-water and vegetation-water interactions, including water demand, constraints and system functioning, give the idea of corresponding Budyko-type framework for human water consumption at the catchment scale. Analogous to variables of Budyko-type models for hydrologic cycle, water demand, water consumption, environmental water use and available water are corresponding to potential evaporation, actual evaporation, runoff and precipitation respectively. Human water consumption data, economic and hydro-meteorological data for 51 human-impacted catchments and 10 major river basins in China are assembled to look for the existence of a Budyko-type relationship for human water consumption, and to seek explanations for the spread in the observed relationship. Guided by this, a Budyko-type analytical model is derived based on application of an optimality principle, that of maximum water benefit. The model derived has the same functional form and mathematical features as those that apply for the original Budyko model. Parameters of the new Budyko-type model for human consumption are linked to economic and social factors. The results of this paper suggest that the functioning of both social and hydrologic subsystems within catchment systems can be explored within

  9. Modelling of Human Transplacental Transport as Performed in Copenhagen, Denmark

    DEFF Research Database (Denmark)

    Mathiesen, L.; Morck, T. A.; Zuri, G.

    2014-01-01

    classes of chemicals and nanoparticles for comparisons across chemical structures as well as different test systems. Our test systems are based on human material to bypass the extrapolation from animal data. By combining data from our two test systems, we are able to rank and compare the transport...... the relationships between maternal and foetal exposures to various compounds including pollutants such as polychlorinated biphenyls, polybrominated flame retardants, nanoparticles as well as recombinant human antibodies. The compounds have been studied in the human placenta perfusion model and to some extent...... in vitro with an established human monolayer trophoblast cell culture model. Results from our studies distinguish placental transport of substances by physicochemical properties, adsorption to placental tissue, binding to transport and receptor proteins and metabolism. We have collected data from different...

  10. Non-Human Primate Models of Orthopoxvirus Infections

    Directory of Open Access Journals (Sweden)

    Anne Schmitt

    2014-06-01

    Full Text Available Smallpox, one of the most destructive diseases, has been successfully eradicated through a worldwide vaccination campaign. Since immunization programs have been stopped, the number of people with vaccinia virus induced immunity is declining. This leads to an increase in orthopoxvirus (OPXV infections in humans, as well as in animals. Additionally, potential abuse of Variola virus (VARV, the causative agent of smallpox, or monkeypox virus, as agents of bioterrorism, has renewed interest in development of antiviral therapeutics and of safer vaccines. Due to its high risk potential, research with VARV is restricted to two laboratories worldwide. Therefore, numerous animal models of other OPXV infections have been developed in the last decades. Non-human primates are especially suitable due to their close relationship to humans. This article provides a review about on non-human primate models of orthopoxvirus infections.

  11. Avian Models for Human Cognitive Neuroscience: A Proposal.

    Science.gov (United States)

    Clayton, Nicola S; Emery, Nathan J

    2015-06-17

    Research on avian cognitive neuroscience over the past two decades has revealed the avian brain to be a better model for understanding human cognition than previously thought, despite differences in the neuroarchitecture of avian and mammalian brains. The brain, behavior, and cognition of songbirds have provided an excellent model of human cognition in one domain, namely learning human language and the production of speech. There are other important behavioral candidates of avian cognition, however, notably the capacity of corvids to remember the past and plan for the future, as well as their ability to think about another's perspective, and physical reasoning. We review this work and assess the evidence that the corvid brain can support such a cognitive architecture. We propose potential applications of these behavioral paradigms for cognitive neuroscience, including recent work on single-cell recordings and neuroimaging in corvids. Finally, we discuss their impact on understanding human developmental cognition. Copyright © 2015 Elsevier Inc. All rights reserved.

  12. Integration of Lightning- and Human-Caused Wildfire Occurrence Models

    DEFF Research Database (Denmark)

    Vilar, Lara; Nieto Solana, Hector; Martín, M. Pilar

    2010-01-01

    Fire risk indices are useful tools for fire prevention actions by fire managers. A fire ignition is either the result of lightning or human activities. In European Mediterranean countries most forest fires are due to human activities. However, lightning is still an important fire ignition source...... in some regions. Integration of lightning and human fire occurrence probability into fire risk indices would be necessary to have a complete picture of the causal agents and their relative importance in fire occurrence. We present two methods for the integration of lightning and human fire occurrence...... probability models at 1 × 1 km grid cell resolution in two regions of Spain: Madrid, which presents a high fire incidence due to human activities; and Aragón, one of the most affected regions in Spain by lightning-fires. For validation, independent fire ignition points were used to compute the Receiver...

  13. Human airway xenograft models of epithelial cell regeneration

    Directory of Open Access Journals (Sweden)

    Puchelle Edith

    2000-10-01

    Full Text Available Abstract Regeneration and restoration of the airway epithelium after mechanical, viral or bacterial injury have a determinant role in the evolution of numerous respiratory diseases such as chronic bronchitis, asthma and cystic fibrosis. The study in vivo of epithelial regeneration in animal models has shown that airway epithelial cells are able to dedifferentiate, spread, migrate over the denuded basement membrane and progressively redifferentiate to restore a functional respiratory epithelium after several weeks. Recently, human tracheal xenografts have been developed in immunodeficient severe combined immunodeficiency (SCID and nude mice. In this review we recall that human airway cells implanted in such conditioned host grafts can regenerate a well-differentiated and functional human epithelium; we stress the interest in these humanized mice in assaying candidate progenitor and stem cells of the human airway mucosa.

  14. An Overview of Human Figure Modeling for Army Aviation Systems

    Science.gov (United States)

    2010-04-01

    space reach and vision analyses, while others are used to examine biomechanics or strength issues, for example. Still other human figure modeling... levers (ECLs) located on the side console panel. Figure 9 shows a large male with insufficient knee clearance at the lower section of the instrument...Measuring Machine CMWS Common Missile Warning System ECL Engine Control Lever FOV Field of View GMC Ground Movement Control HFE Human

  15. Significance of cold-season respiration and photosynthesis in a subarctic heath ecosystem in Northern Sweden

    DEFF Research Database (Denmark)

    Larsen, Klaus Steenberg; Ibrom, Andreas; Jonasson, S.

    2007-01-01

    ecosystem respiration and photosynthesis with a chamber technique at ambient conditions and at artificially, increased frequency of freeze-thaw (FT) cycles during fall and spring. We fitted the measured ecosystem exchange rates to respiration and photosynthesis models with R-2-values ranging from 0.81 to 0......-season photosynthesis partly balanced the cold-season respiratory carbon losses and can be significant for the annual cycle of carbon. Still, during the full year the ecosystem was a significant net source of 120 +/- 12g Cm-2 to the atmosphere. Neither respiration nor photosynthetic rates were much affected...... by the extra FT cycles, although the mean rate of net ecosystem loss decreased slightly, but significantly, in May. The results suggest only a small response of net carbon fluxes to increased frequency of FT cycles in this ecosystem...

  16. Initial Pulmonary Respiration Causes Massive Diaphragm Damage and Hyper-CKemia in Duchenne Muscular Dystrophy Dog

    Science.gov (United States)

    Nakamura, Akinori; Kobayashi, Masanori; Kuraoka, Mutsuki; Yuasa, Katsutoshi; Yugeta, Naoko; Okada, Takashi; Takeda, Shin'ichi

    2013-01-01

    The molecular mechanism of muscle degeneration in a lethal muscle disorder Duchene muscular dystrophy (DMD) has not been fully elucidated. The dystrophic dog, a model of DMD, shows a high mortality rate with a marked increase in serum creatine kinase (CK) levels in the neonatal period. By measuring serum CK levels in cord and venous blood, we found initial pulmonary respiration resulted in massive diaphragm damage in the neonates and thereby lead to the high serum CK levels. Furthermore, molecular biological techniques revealed that osteopontin was prominently upregulated in the dystrophic diaphragm prior to the respiration, and that immediate-early genes (c-fos and egr-1) and inflammation/immune response genes (IL-6, IL-8, COX-2, and selectin E) were distinctly overexpressed after the damage by the respiration. Hence, we segregated dystrophic phases at the molecular level before and after mechanical damage. These molecules could be biomarkers of muscle damage and potential targets in pharmaceutical therapies. PMID:23851606

  17. Hyperglycemia induced damage to mitochondrial respiration in renal mesangial and tubular cells: Implications for diabetic nephropathy.

    Science.gov (United States)

    Czajka, Anna; Malik, Afshan N

    2016-12-01

    Damage to renal tubular and mesangial cells is central to the development of diabetic nephropathy (DN), a complication of diabetes which can lead to renal failure. Mitochondria are the site of cellular respiration and produce energy in the form of ATP via oxidative phosphorylation, and mitochondrial dysfunction has been implicated in DN. Since the kidney is an organ with high bioenergetic needs, we postulated that hyperglycemia causes damage to renal mitochondria resulting in bioenergetic deficit. The bioenergetic profiles and the effect of hyperglycemia on cellular respiration of human primary mesangial (HMCs) and proximal tubular cells (HK-2) were compared in normoglycemic and hyperglycemic conditions using the seahorse bio-analyzer. In normoglycemia, HK-2 had significantly lower basal, ATP-linked and maximal respiration rates, and lower reserve capacity compared to HMCs. Hyperglycemia caused a down-regulation of all respiratory parameters within 4 days in HK-2 but not in HMCs. After 8 days of hyperglycemia, down-regulation of respiratory parameters persisted in tubular cells with compensatory up-regulated glycolysis. HMCs had reduced maximal respiration and reserve capacity at 8 days, and by 12 days had compromised mitochondrial respiration despite which they did not enhance glycolysis. These data suggest that diabetes is likely to lead to a cellular deficit in ATP production in both cell types, although with different sensitivities, and this mechanism could significantly contribute to the cellular damage seen in the diabetic kidney. Prevention of diabetes induced damage to renal mitochondrial respiration may be a novel therapeutic approach for the prevention/treatment of DN. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  18. Effectiveness of Three Decontamination Treatments Against Influenza Virus Applied to Filtering Facepiece Respirators

    Science.gov (United States)

    2010-10-01

    generated steam and moist heat) on two NIOSH certified N95 FFRs contaminated with H5N1. An aerosol settling chamber was used to apply virus-laden droplets to...use FFRs. N95 respirator; decontamination; respirator reuse; influenza virus; healthcare workers; bioaerosol U U U UU 11 Joseph D. Wander, PhD Reset...microwave- generated steam, and moist heat] on two National Institute for Occupational Safety and Health-certified N95 FFRs (3M models 1860s and 1870

  19. Human granuloma in vitro model, for TB dormancy and resuscitation.

    Directory of Open Access Journals (Sweden)

    Nidhi Kapoor

    Full Text Available Tuberculosis (TB is responsible for death of nearly two million people in the world annually. Upon infection, Mycobacterium tuberculosis (Mtb causes formation of granuloma where the pathogen goes into dormant state and can live for decades before resuscitation to develop active disease when the immune system of the host is weakened and/or suppressed. In an attempt to better understand host-pathogen interactions, several groups have been developing in vitro models of human tuberculosis granuloma. However, to date, an in vitro granuloma model in which Mtb goes into dormancy and can subsequently resuscitate under conditions that mimic weakening of the immune system has not been reported. We describe the development of a biomimetic in vitro model of human tuberculosis granuloma using human primary leukocytes, in which the Mtb exhibited characteristics of dormant mycobacteria as demonstrated by (1 loss of acid-fastness, (2 accumulation of lipid bodies (3 development of rifampicin-tolerance and (4 gene expression changes. Further, when these micro granulomas were treated with immunosuppressant anti-tumor necrosis factor-alpha monoclonal antibodies (anti-TNFα mAbs, resuscitation of Mtb was observed as has been found in humans. In this human in vitro granuloma model triacylglycerol synthase 1deletion mutant (Δtgs1 with impaired ability to accumulate triacylglycerides (TG, but not the complemented mutant, could not go into dormancy. Deletion mutant of lipY, with compromised ability to mobilize the stored TG, but not the complemented mutant, was unable to come out of dormancy upon treatment with anti-TNFα mAbs. In conclusion, we have developed an in vitro human tuberculosis granuloma model that largely exhibits functional features of dormancy and resuscitation observed in human tuberculosis.

  20. Contemporary Animal Models For Human Gene Therapy Applications.

    Science.gov (United States)

    Gopinath, Chitra; Nathar, Trupti Job; Ghosh, Arkasubhra; Hickstein, Dennis Durand; Nelson, Everette Jacob Remington

    2015-01-01

    Over the past three decades, gene therapy has been making considerable progress as an alternative strategy in the treatment of many diseases. Since 2009, several studies have been reported in humans on the successful treatment of various diseases. Animal models mimicking human disease conditions are very essential at the preclinical stage before embarking on a clinical trial. In gene therapy, for instance, they are useful in the assessment of variables related to the use of viral vectors such as safety, efficacy, dosage and localization of transgene expression. However, choosing a suitable disease-specific model is of paramount importance for successful clinical translation. This review focuses on the animal models that are most commonly used in gene therapy studies, such as murine, canine, non-human primates, rabbits, porcine, and a more recently developed humanized mice. Though small and large animals both have their own pros and cons as disease-specific models, the choice is made largely based on the type and length of study performed. While small animals with a shorter life span could be well-suited for degenerative/aging studies, large animals with longer life span could suit longitudinal studies and also help with dosage adjustments to maximize therapeutic benefit. Recently, humanized mice or mouse-human chimaeras have gained interest in the study of human tissues or cells, thereby providing a more reliable understanding of therapeutic interventions. Thus, animal models are of great importance with regard to testing new vector technologies in vivo for assessing safety and efficacy prior to a gene therapy clinical trial.

  1. Human performance modeling for system of systems analytics :soldier fatigue.

    Energy Technology Data Exchange (ETDEWEB)

    Lawton, Craig R.; Campbell, James E.; Miller, Dwight Peter

    2005-10-01

    The military has identified Human Performance Modeling (HPM) as a significant requirement and challenge of future systems modeling and analysis initiatives as can be seen in the Department of Defense's (DoD) Defense Modeling and Simulation Office's (DMSO) Master Plan (DoD 5000.59-P 1995). To this goal, the military is currently spending millions of dollars on programs devoted to HPM in various military contexts. Examples include the Human Performance Modeling Integration (HPMI) program within the Air Force Research Laboratory, which focuses on integrating HPMs with constructive models of systems (e.g. cockpit simulations) and the Navy's Human Performance Center (HPC) established in September 2003. Nearly all of these initiatives focus on the interface between humans and a single system. This is insufficient in the era of highly complex network centric SoS. This report presents research and development in the area of HPM in a system-of-systems (SoS). Specifically, this report addresses modeling soldier fatigue and the potential impacts soldier fatigue can have on SoS performance.

  2. A control-theory model for human decision-making

    Science.gov (United States)

    Levison, W. H.; Tanner, R. B.

    1971-01-01

    A model for human decision making is an adaptation of an optimal control model for pilot/vehicle systems. The models for decision and control both contain concepts of time delay, observation noise, optimal prediction, and optimal estimation. The decision making model was intended for situations in which the human bases his decision on his estimate of the state of a linear plant. Experiments are described for the following task situations: (a) single decision tasks, (b) two-decision tasks, and (c) simultaneous manual control and decision making. Using fixed values for model parameters, single-task and two-task decision performance can be predicted to within an accuracy of 10 percent. Agreement is less good for the simultaneous decision and control situation.

  3. Human Posture and Movement Prediction based on Musculoskeletal Modeling

    DEFF Research Database (Denmark)

    Farahani, Saeed Davoudabadi

    2014-01-01

    Abstract This thesis explores an optimization-based formulation, so-called inverse-inverse dynamics, for the prediction of human posture and motion dynamics performing various tasks. It is explained how this technique enables us to predict natural kinematic and kinetic patterns for human posture...... and motion using AnyBody Modeling System (AMS). AMS uses inverse dynamics to analyze musculoskeletal systems and is, therefore, limited by its dependency on input kinematics. We propose to alleviate this dependency by assuming that voluntary postures and movement strategies in humans are guided by a desire...... specifications. The model is then scaled to the desired anthropometric data by means of one of the existing scaling law in AMS. If the simulation results are to be compared with the experimental measurements, the model should be scaled to match the involved subjects. Depending on the scientific question...

  4. Improving Saliency Models by Predicting Human Fixation Patches

    KAUST Repository

    Dubey, Rachit

    2015-04-16

    There is growing interest in studying the Human Visual System (HVS) to supplement and improve the performance of computer vision tasks. A major challenge for current visual saliency models is predicting saliency in cluttered scenes (i.e. high false positive rate). In this paper, we propose a fixation patch detector that predicts image patches that contain human fixations with high probability. Our proposed model detects sparse fixation patches with an accuracy of 84 % and eliminates non-fixation patches with an accuracy of 84 % demonstrating that low-level image features can indeed be used to short-list and identify human fixation patches. We then show how these detected fixation patches can be used as saliency priors for popular saliency models, thus, reducing false positives while maintaining true positives. Extensive experimental results show that our proposed approach allows state-of-the-art saliency methods to achieve better prediction performance on benchmark datasets.

  5. Engineering Large Animal Species to Model Human Diseases.

    Science.gov (United States)

    Rogers, Christopher S

    2016-07-01

    Animal models are an important resource for studying human diseases. Genetically engineered mice are the most commonly used species and have made significant contributions to our understanding of basic biology, disease mechanisms, and drug development. However, they often fail to recreate important aspects of human diseases and thus can have limited utility as translational research tools. Developing disease models in species more similar to humans may provide a better setting in which to study disease pathogenesis and test new treatments. This unit provides an overview of the history of genetically engineered large animals and the techniques that have made their development possible. Factors to consider when planning a large animal model, including choice of species, type of modification and methodology, characterization, production methods, and regulatory compliance, are also covered. © 2016 by John Wiley & Sons, Inc. Copyright © 2016 John Wiley & Sons, Inc.

  6. Large animal models of rare genetic disorders: sheep as phenotypically relevant models of human genetic disease.

    Science.gov (United States)

    Pinnapureddy, Ashish R; Stayner, Cherie; McEwan, John; Baddeley, Olivia; Forman, John; Eccles, Michael R

    2015-09-02

    Animals that accurately model human disease are invaluable in medical research, allowing a critical understanding of disease mechanisms, and the opportunity to evaluate the effect of therapeutic compounds in pre-clinical studies. Many types of animal models are used world-wide, with the most common being small laboratory animals, such as mice. However, rodents often do not faithfully replicate human disease, despite their predominant use in research. This discordancy is due in part to physiological differences, such as body size and longevity. In contrast, large animal models, including sheep, provide an alternative to mice for biomedical research due to their greater physiological parallels with humans. Completion of the full genome sequences of many species, and the advent of Next Generation Sequencing (NGS) technologies, means it is now feasible to screen large populations of domesticated animals for genetic variants that resemble human genetic diseases, and generate models that more accurately model rare human pathologies. In this review, we discuss the notion of using sheep as large animal models, and their advantages in modelling human genetic disease. We exemplify several existing naturally occurring ovine variants in genes that are orthologous to human disease genes, such as the Cln6 sheep model for Batten disease. These, and other sheep models, have contributed significantly to our understanding of the relevant human disease process, in addition to providing opportunities to trial new therapies in animals with similar body and organ size to humans. Therefore sheep are a significant species with respect to the modelling of rare genetic human disease, which we summarize in this review.

  7. Geometric Modeling and Reasoning of Human-Centered Freeform Products

    CERN Document Server

    Wang, Charlie C L

    2013-01-01

    The recent trend in user-customized product design requires the shape of products to be automatically adjusted according to the human body’s shape, so that people will feel more comfortable when wearing these products.  Geometric approaches can be used to design the freeform shape of products worn by people, which can greatly improve the efficiency of design processes in various industries involving customized products (e.g., garment design, toy design, jewel design, shoe design, and design of medical devices, etc.). These products are usually composed of very complex geometric shapes (represented by free-form surfaces), and are not driven by a parameter table but a digital human model with free-form shapes or part of human bodies (e.g., wrist, foot, and head models).   Geometric Modeling and Reasoning of Human-Centered Freeform Products introduces the algorithms of human body reconstruction, freeform product modeling, constraining and reconstructing freeform products, and shape optimization for improving...

  8. Modeling human decision making behavior in supervisory control

    Science.gov (United States)

    Tulga, M. K.; Sheridan, T. B.

    1977-01-01

    An optimal decision control model was developed, which is based primarily on a dynamic programming algorithm which looks at all the available task possibilities, charts an optimal trajectory, and commits itself to do the first step (i.e., follow the optimal trajectory during the next time period), and then iterates the calculation. A Bayesian estimator was included which estimates the tasks which might occur in the immediate future and provides this information to the dynamic programming routine. Preliminary trials comparing the human subject's performance to that of the optimal model show a great similarity, but indicate that the human skips certain movements which require quick change in strategy.

  9. Pearls and pitfalls in human pharmacological models of migraine

    DEFF Research Database (Denmark)

    Ashina, Messoud; Hansen, Jakob Møller; Olesen, Jes

    2013-01-01

    - or migraine-provoking property of naturally occurring signaling molecules can be tested in a human model. If such an endogenous substance can provoke migraine in human patients, then it is likely, although not certain, that blocking its effect will be effective in the treatment of acute migraine attacks...... an important role in translational migraine research leading to the identification of three new principally different targets in the treatment of acute migraine attacks and has been used to examine other endogenous signaling molecules as well as genetic susceptibility factors. New additions to the model...

  10. Making Organisms Model Human Behavior: Situated Models in North-American Alcohol Research, 1950-onwards

    Science.gov (United States)

    Leonelli, Sabina; Ankeny, Rachel A.; Nelson, Nicole C.; Ramsden, Edmund

    2014-01-01

    Argument We examine the criteria used to validate the use of nonhuman organisms in North-American alcohol addiction research from the 1950s to the present day. We argue that this field, where the similarities between behaviors in humans and non-humans are particularly difficult to assess, has addressed questions of model validity by transforming the situatedness of non-human organisms into an experimental tool. We demonstrate that model validity does not hinge on the standardization of one type of organism in isolation, as often the case with genetic model organisms. Rather, organisms are viewed as necessarily situated: they cannot be understood as a model for human behavior in isolation from their environmental conditions. Hence the environment itself is standardized as part of the modeling process; and model validity is assessed with reference to the environmental conditions under which organisms are studied. PMID:25233743

  11. Making organisms model human behavior: situated models in North-American alcohol research, since 1950.

    Science.gov (United States)

    Ankeny, Rachel A; Leonelli, Sabina; Nelson, Nicole C; Ramsden, Edmund

    2014-09-01

    We examine the criteria used to validate the use of nonhuman organisms in North-American alcohol addiction research from the 1950s to the present day. We argue that this field, where the similarities between behaviors in humans and non-humans are particularly difficult to assess, has addressed questions of model validity by transforming the situatedness of non-human organisms into an experimental tool. We demonstrate that model validity does not hinge on the standardization of one type of organism in isolation, as often the case with genetic model organisms. Rather, organisms are viewed as necessarily situated: they cannot be understood as a model for human behavior in isolation from their environmental conditions. Hence the environment itself is standardized as part of the modeling process; and model validity is assessed with reference to the environmental conditions under which organisms are studied.

  12. Coupling of the Models of Human Physiology and Thermal Comfort

    Science.gov (United States)

    Pokorny, J.; Jicha, M.

    2013-04-01

    A coupled model of human physiology and thermal comfort was developed in Dymola/Modelica. A coupling combines a modified Tanabe model of human physiology and thermal comfort model developed by Zhang. The Coupled model allows predicting the thermal sensation and comfort of both local and overall from local boundary conditions representing ambient and personal factors. The aim of this study was to compare prediction of the Coupled model with the Fiala model prediction and experimental data. Validation data were taken from the literature, mainly from the validation manual of software Theseus-FE [1]. In the paper validation of the model for very light physical activities (1 met) indoor environment with temperatures from 12 °C up to 48 °C is presented. The Coupled model predicts mean skin temperature for cold, neutral and warm environment well. However prediction of core temperature in cold environment is inaccurate and very affected by ambient temperature. Evaluation of thermal comfort in warm environment is supplemented by skin wettedness prediction. The Coupled model is designed for non-uniform and transient environmental conditions; it is also suitable simulation of thermal comfort in vehicles cabins. The usage of the model is limited for very light physical activities up to 1.2 met only.

  13. Coupling of the Models of Human Physiology and Thermal Comfort

    Directory of Open Access Journals (Sweden)

    Jicha M.

    2013-04-01

    Full Text Available A coupled model of human physiology and thermal comfort was developed in Dymola/Modelica. A coupling combines a modified Tanabe model of human physiology and thermal comfort model developed by Zhang. The Coupled model allows predicting the thermal sensation and comfort of both local and overall from local boundary conditions representing ambient and personal factors. The aim of this study was to compare prediction of the Coupled model with the Fiala model prediction and experimental data. Validation data were taken from the literature, mainly from the validation manual of software Theseus–FE [1]. In the paper validation of the model for very light physical activities (1 met indoor environment with temperatures from 12 °C up to 48 °C is presented. The Coupled model predicts mean skin temperature for cold, neutral and warm environment well. However prediction of core temperature in cold environment is inaccurate and very affected by ambient temperature. Evaluation of thermal comfort in warm environment is supplemented by skin wettedness prediction. The Coupled model is designed for non-uniform and transient environmental conditions; it is also suitable simulation of thermal comfort in vehicles cabins. The usage of the model is limited for very light physical activities up to 1.2 met only.

  14. Identifying and modeling the structural discontinuities of human interactions

    Science.gov (United States)

    Grauwin, Sebastian; Szell, Michael; Sobolevsky, Stanislav; Hövel, Philipp; Simini, Filippo; Vanhoof, Maarten; Smoreda, Zbigniew; Barabási, Albert-László; Ratti, Carlo

    2017-04-01

    The idea of a hierarchical spatial organization of society lies at the core of seminal theories in human geography that have strongly influenced our understanding of social organization. Along the same line, the recent availability of large-scale human mobility and communication data has offered novel quantitative insights hinting at a strong geographical confinement of human interactions within neighboring regions, extending to local levels within countries. However, models of human interaction largely ignore this effect. Here, we analyze several country-wide networks of telephone calls - both, mobile and landline - and in either case uncover a systematic decrease of communication induced by borders which we identify as the missing variable in state-of-the-art models. Using this empirical evidence, we propose an alternative modeling framework that naturally stylizes the damping effect of borders. We show that this new notion substantially improves the predictive power of widely used interaction models. This increases our ability to understand, model and predict social activities and to plan the development of infrastructures across multiple scales.

  15. Cognitive modelling: a basic complement of human reliability analysis

    International Nuclear Information System (INIS)

    Bersini, U.; Cacciabue, P.C.; Mancini, G.

    1988-01-01

    In this paper the issues identified in modelling humans and machines are discussed in the perspective of the consideration of human errors managing complex plants during incidental as well as normal conditions. The dichotomy between the use of a cognitive versus a behaviouristic model approach is discussed and the complementarity aspects rather than the differences of the two methods are identified. A cognitive model based on a hierarchical goal-oriented approach and driven by fuzzy logic methodology is presented as the counterpart to the 'classical' THERP methodology for studying human errors. Such a cognitive model is discussed at length and its fundamental components, i.e. the High Level Decision Making and the Low Level Decision Making models, are reviewed. Finally, the inadequacy of the 'classical' THERP methodology to deal with cognitive errors is discussed on the basis of a simple test case. For the same case the cognitive model is then applied showing the flexibility and adequacy of the model to dynamic configuration with time-dependent failures of components and with consequent need for changing of strategy during the transient itself. (author)

  16. A biokinetic and dosimetric model for ionic indium in humans

    Science.gov (United States)

    Andersson, Martin; Mattsson, Sören; Johansson, Lennart; Leide-Svegborn, Sigrid

    2017-08-01

    This paper reviews biokinetic data for ionic indium, and proposes a biokinetic model for systemic indium in adult humans. The development of parameter values focuses on human data and indium in the form of ionic indium(III), as indium chloride and indium arsenide. The model presented for systemic indium is defined by five different pools: plasma, bone marrow, liver, kidneys and other soft tissues. The model is based on two subsystems: one corresponding to indium bound to transferrin and one where indium is transported back to the plasma, binds to red blood cell transferrin and is then excreted through the kidneys to the urinary bladder. Absorbed doses to several organs and the effective dose are calculated for 111In- and 113mIn-ions. The proposed biokinetic model is compared with previously published biokinetic indium models published by the ICRP. The absorbed doses are calculated using the ICRP/ICRU adult reference phantoms and the effective dose is estimated according to ICRP Publication 103. The effective doses for 111In and 113mIn are 0.25 mSv MBq-1 and 0.013 mSv MBq-1 respectively. The updated biokinetic and dosimetric models presented in this paper take into account human data and new animal data, which represent more detailed and presumably more accurate dosimetric data than that underlying previous models for indium.

  17. More-Realistic Digital Modeling of a Human Body

    Science.gov (United States)

    Rogge, Renee

    2010-01-01

    A MATLAB computer program has been written to enable improved (relative to an older program) modeling of a human body for purposes of designing space suits and other hardware with which an astronaut must interact. The older program implements a kinematic model based on traditional anthropometric measurements that do provide important volume and surface information. The present program generates a three-dimensional (3D) whole-body model from 3D body-scan data. The program utilizes thin-plate spline theory to reposition the model without need for additional scans.

  18. Elucidation of xenobiotic metabolism pathways in human skin and human skin models by proteomic profiling.

    Directory of Open Access Journals (Sweden)

    Sven van Eijl

    Full Text Available BACKGROUND: Human skin has the capacity to metabolise foreign chemicals (xenobiotics, but knowledge of the various enzymes involved is incomplete. A broad-based unbiased proteomics approach was used to describe the profile of xenobiotic metabolising enzymes present in human skin and hence indicate principal routes of metabolism of xenobiotic compounds. Several in vitro models of human skin have been developed for the purpose of safety assessment of chemicals. The suitability of these epidermal models for studies involving biotransformation was assessed by comparing their profiles of xenobiotic metabolising enzymes with those of human skin. METHODOLOGY/PRINCIPAL FINDINGS: Label-free proteomic analysis of whole human skin (10 donors was applied and analysed using custom-built PROTSIFT software. The results showed the presence of enzymes with a capacity for the metabolism of alcohols through dehydrogenation, aldehydes through dehydrogenation and oxidation, amines through oxidation, carbonyls through reduction, epoxides and carboxylesters through hydrolysis and, of many compounds, by conjugation to glutathione. Whereas protein levels of these enzymes in skin were mostly just 4-10 fold lower than those in liver and sufficient to support metabolism, the levels of cytochrome P450 enzymes were at least 300-fold lower indicating they play no significant role. Four epidermal models of human skin had profiles very similar to one another and these overlapped substantially with that of whole skin. CONCLUSIONS/SIGNIFICANCE: The proteomics profiling approach was successful in producing a comprehensive analysis of the biotransformation characteristics of whole human skin and various in vitro skin models. The results show that skin contains a range of defined enzymes capable of metabolising different classes of chemicals. The degree of similarity of the profiles of the in vitro models indicates their suitability for epidermal toxicity testing. Overall, these

  19. A dystrophic Duchenne mouse model for testing human antisense oligonucleotides.

    Directory of Open Access Journals (Sweden)

    Marcel Veltrop

    Full Text Available Duchenne muscular dystrophy (DMD is a severe muscle-wasting disease generally caused by reading frame disrupting mutations in the DMD gene resulting in loss of functional dystrophin protein. The reading frame can be restored by antisense oligonucleotide (AON-mediated exon skipping, allowing production of internally deleted, but partially functional dystrophin proteins as found in the less severe Becker muscular dystrophy. Due to genetic variation between species, mouse models with mutations in the murine genes are of limited use to test and further optimize human specific AONs in vivo. To address this we have generated the del52hDMD/mdx mouse. This model carries both murine and human DMD genes. However, mouse dystrophin expression is abolished due to a stop mutation in exon 23, while the expression of human dystrophin is abolished due to a deletion of exon 52. The del52hDMD/mdx model, like mdx, shows signs of muscle dystrophy on a histological level and phenotypically mild functional impairment. Local administration of human specific vivo morpholinos induces exon skipping and dystrophin restoration in these mice. Depending on the number of mismatches, occasional skipping of the murine Dmd gene, albeit at low levels, could be observed. Unlike previous models, the del52hDMD/mdx model enables the in vivo analysis of human specific AONs targeting exon 51 or exon 53 on RNA and protein level and muscle quality and function. Therefore, it will be a valuable tool for optimizing human specific AONs and genome editing approaches for DMD.

  20. A Real-Time Model-Based Human Motion Tracking and Analysis for Human-Computer Interface Systems

    Directory of Open Access Journals (Sweden)

    Chung-Lin Huang

    2004-09-01

    Full Text Available This paper introduces a real-time model-based human motion tracking and analysis method for human computer interface (HCI. This method tracks and analyzes the human motion from two orthogonal views without using any markers. The motion parameters are estimated by pattern matching between the extracted human silhouette and the human model. First, the human silhouette is extracted and then the body definition parameters (BDPs can be obtained. Second, the body animation parameters (BAPs are estimated by a hierarchical tritree overlapping searching algorithm. To verify the performance of our method, we demonstrate different human posture sequences and use hidden Markov model (HMM for posture recognition testing.

  1. Investigation and Modeling of Capacitive Human Body Communication.

    Science.gov (United States)

    Zhu, Xiao-Qi; Guo, Yong-Xin; Wu, Wen

    2017-04-01

    This paper presents a systematic investigation of the capacitive human body communication (HBC). The measurement of HBC channels is performed using a novel battery-powered system to eliminate the effects of baluns, cables and instruments. To verify the measured results, a numerical model incorporating the entire HBC system is established. Besides, it is demonstrated that both the impedance and path gain bandwidths of HBC channels is affected by the electrode configuration. Based on the analysis of the simulated electric field distribution, an equivalent circuit model is proposed and the circuit parameters are extracted using the finite element method. The transmission capability along the human body is also studied. The simulated results using the numerical and circuit models coincide very well with the measurement, which demonstrates that the proposed circuit model can effectively interpret the operation mechanism of the capacitive HBC.

  2. Sensitivity analysis techniques for models of human behavior.

    Energy Technology Data Exchange (ETDEWEB)

    Bier, Asmeret Brooke

    2010-09-01

    Human and social modeling has emerged as an important research area at Sandia National Laboratories due to its potential to improve national defense-related decision-making in the presence of uncertainty. To learn about which sensitivity analysis techniques are most suitable for models of human behavior, different promising methods were applied to an example model, tested, and compared. The example model simulates cognitive, behavioral, and social processes and interactions, and involves substantial nonlinearity, uncertainty, and variability. Results showed that some sensitivity analysis methods create similar results, and can thus be considered redundant. However, other methods, such as global methods that consider interactions between inputs, can generate insight not gained from traditional methods.

  3. A kinematic model for Bayesian tracking of cyclic human motion

    Science.gov (United States)

    Greif, Thomas; Lienhart, Rainer

    2010-01-01

    We introduce a two-dimensional kinematic model for cyclic motions of humans, which is suitable for the use as temporal prior in any Bayesian tracking framework. This human motion model is solely based on simple kinematic properties: the joint accelerations. Distributions of joint accelerations subject to the cycle progress are learned from training data. We present results obtained by applying the introduced model to the cyclic motion of backstroke swimming in a Kalman filter framework that represents the posterior distribution by a Gaussian. We experimentally evaluate the sensitivity of the motion model with respect to the frequency and noise level of assumed appearance-based pose measurements by simulating various fidelities of the pose measurements using ground truth data.

  4. Animation of 3D Model of Human Head

    Directory of Open Access Journals (Sweden)

    V. Michalcin

    2007-04-01

    Full Text Available The paper deals with the new algorithm of animation of 3D model of the human head in combination with its global motion. The designed algorithm is very fast and with low calculation requirements, because it does not need the synthesis of the input videosequence for estimation of the animation parameters as well as the parameters of global motion. The used 3D model Candide generates different expressions using its animation units which are controlled by the animation parameters. These ones are estimated on the basis of optical flow without the need of extracting of the feature points in the frames of the input videosequence because they are given by the selected vertices of the animation units of the calibrated 3D model Candide. The established multiple iterations inside the designed animation algorithm of 3D model of the human head between two successive frames significantly improved its accuracy above all for the large motion.

  5. Mechanics, Mechanobiology, and Modeling of Human Abdominal Aorta and Aneurysms

    Science.gov (United States)

    Humphrey, J.D.; Holzapfel, G.A.

    2011-01-01

    Biomechanical factors play fundamental roles in the natural history of abdominal aortic aneurysms (AAAs) and their responses to treatment. Advances during the past two decades have increased our understanding of the mechanics and biology of the human abdominal aorta and AAAs, yet there remains a pressing need for considerable new data and resulting patient-specific computational models that can better describe the current status of a lesion and better predict the evolution of lesion geometry, composition, and material properties and thereby improve interventional planning. In this paper, we briefly review data on the structure and function of the human abdominal aorta and aneurysmal wall, past models of the mechanics, and recent growth and remodeling models. We conclude by identifying open problems that we hope will motivate studies to improve our computational modeling and thus general understanding of AAAs. PMID:22189249

  6. Modeling Human Cardiac Hypertrophy in Stem Cell-Derived Cardiomyocytes

    Directory of Open Access Journals (Sweden)

    Ekaterina Ovchinnikova

    2018-03-01

    Full Text Available Summary: Cardiac hypertrophy accompanies many forms of cardiovascular diseases. The mechanisms behind the development and regulation of cardiac hypertrophy in the human setting are poorly understood, which can be partially attributed to the lack of a human cardiomyocyte-based preclinical test system recapitulating features of diseased myocardium. The objective of our study is to determine whether human embryonic stem cell-derived cardiomyocytes (hESC-CMs subjected to mechanical stretch can be used as an adequate in vitro model for studying molecular mechanisms of cardiac hypertrophy. We show that hESC-CMs subjected to cyclic stretch, which mimics mechanical overload, exhibit essential features of a hypertrophic state on structural, functional, and gene expression levels. The presented hESC-CM stretch approach provides insight into molecular mechanisms behind mechanotransduction and cardiac hypertrophy and lays groundwork for the development of pharmacological approaches as well as for discovering potential circulating biomarkers of cardiac dysfunction. : In this article, Berezikov, van der Meer, and colleagues used stem cell-derived cardiomyocytes to model human cardiac hypertrophy. Their approach provides novel insights into molecular mechanisms behind mechanotransduction and cardiac hypertrophy and lays groundwork for the development of new pharmacological approaches as well as for discovering new potential circulating biomarkers of cardiac dysfunction. Keywords: stem cells, human cardiomyocytes, hypertrophy, in vitro disease modeling, cardiomyocytes stretch response, mechanotransduction

  7. Recent progress in human reliability models for nuclear power safety

    International Nuclear Information System (INIS)

    Bersini, U.; Devooght, J.; Smidts, C.

    1988-01-01

    The importance of a human factor in the safety of nuclear power plants hardly needs to be stressed after the Three Mile Island and Chernobyl accidents. Following TMI, such progress was made that Chernobyl did not reveal significant faults in the design or operation of Western nuclear power plants. Post-TMI progress concerns: design of control rooms, development of simulators for training operators, use of computer aided diagnostics, a better understanding of procedural safety, the collection of human error data, etc. We shall concentrate here on the specific point of modelling human errors for incorporation in the standard tools of reliability and safety engineering (e.g. fault trees). The Rasmussen report (WASH 1400) has already included human error in the analysis of fault and event trees and since then new models have been developed and tested. Human reliability methods, which first appeared in the early 1980s, model operator behavior during routine tasks and quantify his error probability. Here three of these methods are briefly described: THERP, SLIM and MAPPS. 17 refs

  8. 3D active workspace of human hand anatomical model

    Directory of Open Access Journals (Sweden)

    Ungureanu Loredana

    2007-05-01

    Full Text Available Abstract Background If the model of the human hand is created with accuracy by respecting the type of motion provided by each articulation and the dimensions of articulated bones, it can function as the real organ providing the same motions. Unfortunately, the human hand is hard to model due to its kinematical chains submitted to motion constraints. On the other hand, if an application does not impose a fine manipulation it is not necessary to create a model as complex as the human hand is. But always the hand model has to perform a certain space of motions in imposed workspace architecture no matter what the practical application does. Methods Based on Denavit-Hartenberg convention, we conceived the kinematical model of the human hand, having in mind the structure and the behavior of the natural model. We obtained the kinematical equations describing the motion of every fingertip with respect to the general coordinate system, placed on the wrist. For every joint variable, a range of motion was established. Dividing these joint variables to an appropriate number of intervals and connecting them, the complex surface bordering the active hand model workspace was obtained. Results Using MATLAB 7.0, the complex surface described by fingertips, when hand articulations are all simultaneously moving, was obtained. It can be seen that any point on surface has its own coordinates smaller than the maximum length of the middle finger in static position. Therefore, a sphere having the centre in the origin of the general coordinate system and the radius which equals this length covers the represented complex surface. Conclusion We propose a human hand model that represents a new solution compared to the existing ones. This model is capable to make special movements like power grip and dexterous manipulations. During them, the fingertips do not exceed the active workspace encapsulated by determined surfaces. The proposed kinematical model can help to choose

  9. Propagation of Computer Virus under Human Intervention: A Dynamical Model

    OpenAIRE

    Chenquan Gan; Xiaofan Yang; Wanping Liu; Qingyi Zhu; Xulong Zhang

    2012-01-01

    This paper examines the propagation behavior of computer virus under human intervention. A dynamical model describing the spread of computer virus, under which a susceptible computer can become recovered directly and an infected computer can become susceptible directly, is proposed. Through a qualitative analysis of this model, it is found that the virus-free equilibrium is globally asymptotically stable when the basic reproduction number R0≤1, whereas the viral equilibrium is globally asympt...

  10. Modeling Aggressive Medulloblastoma Using Human Induced Pluripotent Stem Cells

    Science.gov (United States)

    2017-09-01

    Determine if AngII promotes MB cell tumorigenicity through a AT1R-MYC positive feedback loop. This aim will build on our working model that AngII...AWARD NUMBER: W81XWH-14-1-0176 TITLE: Modeling Aggressive Medulloblastoma Using Human-Induced Pluripotent Stem Cells PRINCIPAL INVESTIGATOR...DOCUMENTATION PAGE Form Approved OMB No. 0704-0188 Public reporting burden for this collection of information is estimated to average 1 hour per response

  11. Fractional calculus model of electrical impedance applied to human skin.

    Science.gov (United States)

    Vosika, Zoran B; Lazovic, Goran M; Misevic, Gradimir N; Simic-Krstic, Jovana B

    2013-01-01

    Fractional calculus is a mathematical approach dealing with derivatives and integrals of arbitrary and complex orders. Therefore, it adds a new dimension to understand and describe basic nature and behavior of complex systems in an improved way. Here we use the fractional calculus for modeling electrical properties of biological systems. We derived a new class of generalized models for electrical impedance and applied them to human skin by experimental data fitting. The primary model introduces new generalizations of: 1) Weyl fractional derivative operator, 2) Cole equation, and 3) Constant Phase Element (CPE). These generalizations were described by the novel equation which presented parameter [Formula: see text] related to remnant memory and corrected four essential parameters [Formula: see text] We further generalized single generalized element by introducing specific partial sum of Maclaurin series determined by parameters [Formula: see text] We defined individual primary model elements and their serial combination models by the appropriate equations and electrical schemes. Cole equation is a special case of our generalized class of models for[Formula: see text] Previous bioimpedance data analyses of living systems using basic Cole and serial Cole models show significant imprecisions. Our new class of models considerably improves the quality of fitting, evaluated by mean square errors, for bioimpedance data obtained from human skin. Our models with new parameters presented in specific partial sum of Maclaurin series also extend representation, understanding and description of complex systems electrical properties in terms of remnant memory effects.

  12. Fractional calculus model of electrical impedance applied to human skin.

    Directory of Open Access Journals (Sweden)

    Zoran B Vosika

    Full Text Available Fractional calculus is a mathematical approach dealing with derivatives and integrals of arbitrary and complex orders. Therefore, it adds a new dimension to understand and describe basic nature and behavior of complex systems in an improved way. Here we use the fractional calculus for modeling electrical properties of biological systems. We derived a new class of generalized models for electrical impedance and applied them to human skin by experimental data fitting. The primary model introduces new generalizations of: 1 Weyl fractional derivative operator, 2 Cole equation, and 3 Constant Phase Element (CPE. These generalizations were described by the novel equation which presented parameter [Formula: see text] related to remnant memory and corrected four essential parameters [Formula: see text] We further generalized single generalized element by introducing specific partial sum of Maclaurin series determined by parameters [Formula: see text] We defined individual primary model elements and their serial combination models by the appropriate equations and electrical schemes. Cole equation is a special case of our generalized class of models for[Formula: see text] Previous bioimpedance data analyses of living systems using basic Cole and serial Cole models show significant imprecisions. Our new class of models considerably improves the quality of fitting, evaluated by mean square errors, for bioimpedance data obtained from human skin. Our models with new parameters presented in specific partial sum of Maclaurin series also extend representation, understanding and description of complex systems electrical properties in terms of remnant memory effects.

  13. Mathematical models of human cerebellar development in the fetal period.

    Science.gov (United States)

    Dudek, Krzysztof; Nowakowska-Kotas, Marta; Kędzia, Alicja

    2018-04-01

    The evaluation of cerebellar growth in the fetal period forms a part of a widely used examination to identify any features of abnormalities in early stages of human development. It is well known that the development of anatomical structures, including the cerebellum, does not always follow a linear model of growth. The aim of the study was to analyse a variety of mathematical models of human cerebellar development in fetal life to determine their adequacy. The study comprised 101 fetuses (48 males and 53 females) between the 15th and 28th weeks of fetal life. The cerebellum was exposed and measurements of the vermis and hemispheres were performed, together with statistical analyses. The mathematical model parameters of fetal growth were assessed for crown-rump length (CRL) increases, transverse cerebellar diameter and ventrodorsal dimensions of the cerebellar vermis in the transverse plane, and rostrocaudal dimensions of the cerebellar vermis and hemispheres in the frontal plane. A variety of mathematical models were applied, including linear and non-linear functions. Taking into consideration the variance between models and measurements, as well as correlation parameters, the exponential and Gompertz models proved to be the most suitable for modelling cerebellar growth in the second and third trimesters of pregnancy. However, the linear model gave a satisfactory approximation of cerebellar growth, especially in older fetuses. The proposed models of fetal cerebellar growth constructed on the basis of anatomical examination and objective mathematical calculations could be useful in the estimation of fetal development. © 2018 Anatomical Society.

  14. A validation study of a stochastic model of human interaction

    Science.gov (United States)

    Burchfield, Mitchel Talmadge

    The purpose of this dissertation is to validate a stochastic model of human interactions which is part of a developmentalism paradigm. Incorporating elements of ancient and contemporary philosophy and science, developmentalism defines human development as a progression of increasing competence and utilizes compatible theories of developmental psychology, cognitive psychology, educational psychology, social psychology, curriculum development, neurology, psychophysics, and physics. To validate a stochastic model of human interactions, the study addressed four research questions: (a) Does attitude vary over time? (b) What are the distributional assumptions underlying attitudes? (c) Does the stochastic model, {-}N{intlimitssbsp{-infty}{infty}}varphi(chi,tau)\\ Psi(tau)dtau, have utility for the study of attitudinal distributions and dynamics? (d) Are the Maxwell-Boltzmann, Fermi-Dirac, and Bose-Einstein theories applicable to human groups? Approximately 25,000 attitude observations were made using the Semantic Differential Scale. Positions of individuals varied over time and the logistic model predicted observed distributions with correlations between 0.98 and 1.0, with estimated standard errors significantly less than the magnitudes of the parameters. The results bring into question the applicability of Fisherian research designs (Fisher, 1922, 1928, 1938) for behavioral research based on the apparent failure of two fundamental assumptions-the noninteractive nature of the objects being studied and normal distribution of attributes. The findings indicate that individual belief structures are representable in terms of a psychological space which has the same or similar properties as physical space. The psychological space not only has dimension, but individuals interact by force equations similar to those described in theoretical physics models. Nonlinear regression techniques were used to estimate Fermi-Dirac parameters from the data. The model explained a high degree

  15. Mathematical model of liver regeneration in human live donors.

    Science.gov (United States)

    Periwal, V; Gaillard, J R; Needleman, L; Doria, C

    2014-05-01

    Liver regeneration after injury occurs in many mammals. Rat liver regenerates after partial hepatectomy over a period of 2 weeks while human liver regeneration takes several months. Notwithstanding this enormous difference in time-scales, with new data from five human live liver transplant donors, we show that a mathematical model of rat liver regeneration can be transferred to human, with all biochemical interactions and signaling unchanged. Only six phenomenological parameters need change, and three of these parameter changes are rescalings of rate constants by the ratio of human lifespan to rat lifespan. Data from three donor subjects with approximately equal resections were used to fit the three parameters and the data from the other two donor subjects was used to independently verify the fit. © 2013 Wiley Periodicals, Inc.

  16. Human Nonindependent Mate Choice: Is Model Female Attractiveness Everything?

    Directory of Open Access Journals (Sweden)

    Antonios Vakirtzis

    2012-04-01

    Full Text Available Following two decades of research on non-human animals, there has recently been increased interest in human nonindependent mate choice, namely the ways in which choosing women incorporate information about a man's past or present romantic partners (‘model females’ into their own assessment of the male. Experimental studies using static facial images have generally found that men receive higher desirability ratings from female raters when presented with attractive (compared to unattractive model females. This phenomenon has a straightforward evolutionary explanation: the fact that female mate value is more dependent on physical attractiveness compared to male mate value. Furthermore, due to assortative mating for attractiveness, men who are paired with attractive women are more likely to be of high mate value themselves. Here, we also examine the possible relevance of model female cues other than attractiveness (personality and behavioral traits by presenting video recordings of model females to a set of female raters. The results confirm that the model female's attractiveness is the primary cue. Contrary to some earlier findings in the human and nonhuman literature, we found no evidence that female raters prefer partners of slightly older model females. We conclude by suggesting some promising variations on the present experimental design.

  17. Computational approaches for modeling human intestinal absorption and permeability.

    Science.gov (United States)

    Subramanian, Govindan; Kitchen, Douglas B

    2006-07-01

    Human intestinal absorption (HIA) is an important roadblock in the formulation of new drug substances. Computational models are needed for the rapid estimation of this property. The measurements are determined via in vivo experiments or in vitro permeability studies. We present several computational models that are able to predict the absorption of drugs by the human intestine and the permeability through human Caco-2 cells. The training and prediction sets were derived from literature sources and carefully examined to eliminate compounds that are actively transported. We compare our results to models derived by other methods and find that the statistical quality is similar. We believe that models derived from both sources of experimental data would provide greater consistency in predictions. The performance of several QSPR models that we investigated to predict outside the training set for either experimental property clearly indicates that caution should be exercised while applying any of the models for quantitative predictions. However, we are able to show that the qualitative predictions can be obtained with close to a 70% success rate.

  18. Construction of Gait Adaptation Model in Human Splitbelt Treadmill Walking

    Directory of Open Access Journals (Sweden)

    Yuji Otoda

    2009-01-01

    Full Text Available There are a huge number of studies that measure kinematics, dynamics, the oxygen uptake and so on in human walking on the treadmill. Especially in walking on the splitbelt treadmill where the speed of the right and left belt is different, remarkable differences in kinematics are seen between normal and cerebellar disease subjects. In order to construct the gait adaptation model of such human splitbelt treadmill walking, we proposed a simple control model and made a newly developed 2D biped robot walk on the splitbelt treadmill. We combined the conventional limit-cycle based control consisting of joint PD-control, cyclic motion trajectory planning and a stepping reflex with a newly proposed adjustment of P-gain at the hip joint of the stance leg. We showed that the data of robot (normal subject model and cerebellum disease subject model experiments had high similarities with the data of normal subjects and cerebellum disease subjects experiments carried out by Reisman et al. (2005 and Morton and Bastian (2006 in ratios and patterns. We also showed that P-gain at the hip joint of the stance leg was the control parameter of adaptation for symmetric gaits in splitbelt walking and P-gain adjustment corresponded to muscle stiffness adjustment by the cerebellum. Consequently, we successfully proposed the gait adaptation model in human splitbelt treadmill walking and confirmed the validity of our hypotheses and the proposed model using the biped robot.

  19. Human-centric decision-making models for social sciences

    CERN Document Server

    Pedrycz, Witold

    2014-01-01

    The volume delivers a wealth of effective methods to deal with various types of uncertainty inherently existing in human-centric decision problems. It elaborates on  comprehensive decision frameworks to handle different decision scenarios, which help use effectively the explicit and tacit knowledge and intuition, model perceptions and preferences in a more human-oriented style. The book presents original approaches and delivers new results on fundamentals and applications related to human-centered decision making approaches to business, economics and social systems. Individual chapters cover multi-criteria (multiattribute) decision making, decision making with prospect theory, decision making with incomplete probabilistic information, granular models of decision making and decision making realized with the use of non-additive measures. New emerging decision theories being presented as along with a wide spectrum of ongoing research make the book valuable to all interested in the field of advanced decision-mak...

  20. Maintenance modeling and optimization integrating human and material resources

    Energy Technology Data Exchange (ETDEWEB)

    Martorell, S., E-mail: smartore@iqn.upv.e [Dpto. Ingenieria Quimica y Nuclear, Universidad Politecnica Valencia (Spain); Villamizar, M.; Carlos, S. [Dpto. Ingenieria Quimica y Nuclear, Universidad Politecnica Valencia (Spain); Sanchez, A. [Dpto. Estadistica e Investigacion Operativa Aplicadas y Calidad, Universidad Politecnica Valencia (Spain)

    2010-12-15

    Maintenance planning is a subject of concern to many industrial sectors as plant safety and business depend on it. Traditionally, the maintenance planning is formulated in terms of a multi-objective optimization (MOP) problem where reliability, availability, maintainability and cost (RAM+C) act as decision criteria and maintenance strategies (i.e. maintenance tasks intervals) act as the only decision variables. However the appropriate development of each maintenance strategy depends not only on the maintenance intervals but also on the resources (human and material) available to implement such strategies. Thus, the effect of the necessary resources on RAM+C needs to be modeled and accounted for in formulating the MOP affecting the set of objectives and constraints. In this paper RAM+C models to explicitly address the effect of human resources and material resources (spare parts) on RAM+C criteria are proposed. This extended model allows accounting for explicitly how the above decision criteria depends on the basic model parameters representing the type of strategies, maintenance intervals, durations, human resources and material resources. Finally, an application case is performed to optimize the maintenance plan of a motor-driven pump equipment considering as decision variables maintenance and test intervals and human and material resources.

  1. 3-D Model of the Human Respiratory System

    Science.gov (United States)

    The U.S. EPA’s Office of Research and Development (ORD) has developed a 3-D computational fluid dynamics (CFD) model of the human respiratory system that allows for the simulation of particulate based contaminant deposition and clearance, while being adaptable for age, ethn...

  2. Integrated Human Behavior Modeling and Stochastic Control (IHBMSC)

    Science.gov (United States)

    2014-08-01

    angle, dwell time, workload). For a 50% target density scenario where the operator discrimination task is fairly difficult, the integrated human ... behavior model and stochastic controller (IHBMSC) was shown to reduce the FA rate from 35% to 5%. Also, the IHBMSC performance was found to be quite robust for lower target densities (5%) and different operators.

  3. Modelling the dynamics of Chikungunya in human and mosquito ...

    African Journals Online (AJOL)

    In this paper, we developed and qualitatively analyzed a model for the transmission dynamics of chikungunya virus in a human a nd mosquito populations. The chikungunya virus is transmitted by Aedes mosquitoes usually Aedes albopictus mosquito and it is of big threat to global public health. Rigorous analysis of the ...

  4. Probabilistic Model for Laser Damage to the Human Retina

    Science.gov (United States)

    2012-03-01

    copyright protection in the United States. AFIT-OR-MS-ENS-12-30 PROBABILISTIC MODEL FOR LASER DAMAGE TO THE HUMAN RETINA THESIS Presented to the Faculty of...described by refractive error. Eyeglasses and contact lenses are able to correct for refractive errors by reforming the light entering into the cornea

  5. Building a 3-D Appearance Model of the Human Face

    DEFF Research Database (Denmark)

    Sjöstrand, Karl; Larsen, Rasmus; Lading, Brian

    2003-01-01

    This paper describes a method for building an appearance model from three-dimensional data of human faces. The data consists of 3-D vertices, polygons and a texture map. The method uses a set of nine manually placed landmarks to automatically form a dense correspondence of thousands of points. Th...

  6. Simplified human thermoregulatory model for designing wearable thermoelectric devices

    Science.gov (United States)

    Wijethunge, Dimuthu; Kim, Donggyu; Kim, Woochul

    2018-02-01

    Research on wearable and implantable devices have become popular with the strong need in market. A precise understanding of the thermal properties of human skin, which are not constant values but vary depending on ambient condition, is required for the development of such devices. In this paper, we present simplified human thermoregulatory model for accurately estimating the thermal properties of the skin without applying rigorous calculations. The proposed model considers a variable blood flow rate through the skin, evaporation functions, and a variable convection heat transfer from the skin surface. In addition, wearable thermoelectric generation (TEG) and refrigeration devices were simulated. We found that deviations of 10-60% can be resulted in estimating TEG performance without considering human thermoregulatory model owing to the fact that thermal resistance of human skin is adapted to ambient condition. Simplicity of the modeling procedure presented in this work could be beneficial for optimizing and predicting the performance of any applications that are directly coupled with skin thermal properties.

  7. Observations and modeling of deterministic properties of human ...

    Indian Academy of Sciences (India)

    Simple models show that in Type-I intermittency a characteristic U-shaped probability distribution is obtained for the laminar phase length. The laminar phase length distribution characteristic for Type-I intermittency may be obtained in human heart rate variability data for some cases of pathology. The heart and its regulatory ...

  8. Maintenance modeling and optimization integrating human and material resources

    International Nuclear Information System (INIS)

    Martorell, S.; Villamizar, M.; Carlos, S.; Sanchez, A.

    2010-01-01

    Maintenance planning is a subject of concern to many industrial sectors as plant safety and business depend on it. Traditionally, the maintenance planning is formulated in terms of a multi-objective optimization (MOP) problem where reliability, availability, maintainability and cost (RAM+C) act as decision criteria and maintenance strategies (i.e. maintenance tasks intervals) act as the only decision variables. However the appropriate development of each maintenance strategy depends not only on the maintenance intervals but also on the resources (human and material) available to implement such strategies. Thus, the effect of the necessary resources on RAM+C needs to be modeled and accounted for in formulating the MOP affecting the set of objectives and constraints. In this paper RAM+C models to explicitly address the effect of human resources and material resources (spare parts) on RAM+C criteria are proposed. This extended model allows accounting for explicitly how the above decision criteria depends on the basic model parameters representing the type of strategies, maintenance intervals, durations, human resources and material resources. Finally, an application case is performed to optimize the maintenance plan of a motor-driven pump equipment considering as decision variables maintenance and test intervals and human and material resources.

  9. Animal models of human respiratory syncytial virus disease

    NARCIS (Netherlands)

    Bem, Reinout A.; Domachowske, Joseph B.; Rosenberg, Helene F.

    2011-01-01

    Infection with the human pneumovirus pathogen, respiratory syncytial virus (hRSV), causes a wide spectrum of respiratory disease, notably among infants and the elderly. Laboratory animal studies permit detailed experimental modeling of hRSV disease and are therefore indispensable in the search for

  10. [Soil heterotrophic respiration and its sensitivity to soil temperature and moisture in Liquidambar formosana and Pinus massoniana forests in hilly areas of southeast Hubei Province, China].

    Science.gov (United States)

    Wang, Chuan-hua; Chen, Fang-qing; Wang, Yuan; Li, Jun-qing

    2011-03-01

    Field monitoring was conducted to study the annual dynamics of soil heterotrophic respiration and soil temperature and moisture in Liquidambar formosana and Pinus massoniana forests in hilly areas of southeast Hubei Province, China. At the same time, laboratory experiment was performed to study the heterotrophic respiration rate along soil profile, and the sensitivity of surface soil (0-5 cm) heterotrophic respiration to soil temperature and moisture. Then, a model was established to valuate the potential effects of warming change on the soil heterotrophic respiration in study area. In L. formosana and P. massoniana forests, the soil heterotrophic respiration rate in 0-5 cm layer was 2.39 and 2.62 times, and 2.01 and 2.94 times of that in 5-10 cm and 10-20 cm layers, respectively, illustrating that soil heterotrophic respiration mainly occurred in 0-5 cm surface layer. The temperature sensitivity factor (Q10) of soil heterotrophic respiration in 0-5 cm, 5-10 cm, and 10-20 cm layers was 2.10, 1.86, and 1.78 in L. formosana forest, and 1.86, 1.77, and 1.44 in P. massoniana forest, respectively. The relationship between surface soil heterotrophic respiration and temperature (T) well fitted exponential function R = alphaexp (beta3T), and that between surface soil heterotrophic respiration and moisture (W) well fitted quadratic function R = a+bW+cW2. Therefore, the relationship of surface soil heterotrophic respiration with soil temperature and moisture could be described by the model lnR = a+bW+cW2 +dT+eT2, which suggested that the response of soil heterotrophic respiration to soil moisture was depended on soil temperature, i.e., the sensitivity decreased with decreasing soil temperature. The calculation of the annual soil heterotrophic respiration rate in the two forests with the established model showed that the calculated respiration rate was a slightly higher in L. formosana forest but close to the measured one in P. massoniana forest, illustrating the applied

  11. Isotope partitioning of soil respiration: A Bayesian solution to accommodate multiple sources of variability

    Science.gov (United States)

    Ogle, Kiona; Pendall, Elise

    2015-02-01

    Isotopic methods offer great potential for partitioning trace gas fluxes such as soil respiration into their different source contributions. Traditional partitioning methods face challenges due to variability introduced by different measurement methods, fractionation effects, and end-member uncertainty. To address these challenges, we describe a hierarchical Bayesian (HB) approach for isotopic partitioning of soil respiration that directly accommodates such variability. We apply our HB method to data from an experiment conducted in a shortgrass steppe ecosystem, where decomposition was previously shown to be stimulated by elevated CO2. Our approach simultaneously fits Keeling plot (KP) models to observations of soil or soil-respired δ13C and [CO2] obtained via chambers and gas wells, corrects the KP intercepts for apparent fractionation (Δ) due to isotope-specific diffusion rates and/or method artifacts, estimates method- and treatment-specific values for Δ, propagates end-member uncertainty, and calculates proportional contributions from two distinct respiration sources ("old" and "new" carbon). The chamber KP intercepts were estimated with greater confidence than the well intercepts and compared to the theoretical value of 4.4‰, our results suggest that Δ varies between 2 and 5.2‰ depending on method (chambers versus wells) and CO2 treatment. Because elevated CO2 plots were fumigated with 13C-depleted CO2, the source contributions were tightly constrained, and new C accounted for 64% (range = 55-73%) of soil respiration. The contributions were less constrained for the ambient CO2 treatments, but new C accounted for significantly less (47%, range = 15-82%) of soil respiration. Our new HB partitioning approach contrasts our original analysis (higher contribution of old C under elevated CO2) because it uses additional data sources, accounts for end-member bias, and estimates apparent fractionation effects.

  12. Pollen tube energetics: respiration, fermentation and the race to the ovule.

    Science.gov (United States)

    Rounds, Caleb M; Winship, Lawrence J; Hepler, Peter K

    2011-01-01

    Pollen tubes grow by transferring chemical energy from stored cellular starch and newly assimilated sugars into ATP. This drives myriad processes essential for cell elongation, directly or through the creation of ion gradients. Respiration plays a central role in generating and regulating this energy flow and thus in the success of plant reproduction. Pollen tubes are easily grown in vitro and have become an excellent model for investigating the contributions of respiration to plant cellular growth and morphogenesis at the molecular, biochemical and physiological levels. In recent decades, pollen tube research has become increasingly focused on the molecular mechanisms involved in cellular processes. Yet, effective growth and development requires an intact, integrated set of cellular processes, all supplied with a constant flow of energy. Here we bring together information from the current and historical literature concerning respiration, fermentation and mitochondrial physiology in pollen tubes, and assess the significance of more recent molecular and genetic investigations in a physiological context. The rapid growth of the pollen tube down the style has led to the evolution of high rates of pollen tube respiration. Respiration rates in lily predict a total energy turnover of 40-50 fmol ATP s(-1) per pollen grain. Within this context we examine the energetic requirements of cell wall synthesis, osmoregulation, actin dynamics and cyclosis. At present, we can only estimate the amount of energy required, because data from growing pollen tubes are not available. In addition to respiration, we discuss fermentation and mitochondrial localization. We argue that the molecular pathways need to be examined within the physiological context to understand better the mechanisms that control tip growth in pollen tubes.

  13. Soil Respiration in Eddy Covariance Footprints: A Critical Look at Researcher Needs

    Science.gov (United States)

    Gabriel, Carrie-Ellen; Nickerson, Nick; Creelman, Chance

    2017-04-01

    Eddy covariance (EC) systems have been widely used across the globe for more than 20 years, offering researchers invaluable measurements of parameters including Net Ecosystem Exchange and ecosystem respiration. However, recent research suggests that EC assumptions and technical obstacles may cause biased gas exchange estimates. Measurements of soil respiration (RS) at the ground level may help alleviate these biases; for example, by allowing researchers to reconcile nocturnal EC flux data with soil respiration or by providing a means to inform gap-filling models. RS measurements have been used sparingly alongside EC towers because of the large cost required to scale chamber systems to the EC footprint, as well as data integration and processing burdens. Here we present how the Forced Diffusion (FD) method is ideal for the measurement of RS at EC sites. The FD method allows for inexpensive and autonomous measurements, providing a scalable approach to matching the EC footprint compared to other RS systems. Here, we briefly present the methodology and results from a pilot study at the Howland Forest AmeriFlux site (Maine), carried out during the summer and fall of 2016, measuring soil respiration using the FD chamber technique. The emphasis of the remainder of the research is on gathering, interpreting and actualizing feedback from soil scientists and eddy covariance researchers and technicians on aspects of the FD methodology, deployment style, integration with existing infrastructure and data quality. Our goal is to eventually provide a framework for "ideal soil respiration measurements" that can be used by researchers, engineers and companies to develop functional and reliable soil respiration data sets that are easily coupled with data measured by EC users, and larger EC networks such as AmeriFlux and EuroFlux.

  14. Soil warming increases metabolic quotients of soil microorganisms without changes in temperature sensitivity of soil respiration

    Science.gov (United States)

    Marañón-Jiménez, Sara; Soong, Jenniffer L.; Leblans, Niki I. W.; Sigurdsson, Bjarni D.; Dauwe, Steven; Fransen, Erik; Janssens, Ivan A.

    2017-04-01

    Increasing temperatures can accelerate soil organic matter (SOM) decomposition and release large amounts of CO2 to the atmosphere, potentially inducing climate change feedbacks. Alterations to the temperature sensitivity and metabolic pathways of soil microorganisms in response to soil warming can play a key role in these soil carbon (C) losses. Here, we present results of an incubation experiment using soils from a geothermal gradient in Iceland that have been subjected to different intensities of soil warming (+0, +1, +3, +5, +10 and +20 °C above ambient) over seven years. We hypothesized that 7 years of soil warming would led to a depletion of labile organic substrates, with a subsequent decrease of the "apparent" temperature sensitivity of soil respiration. Associated to this C limitation and more sub-optimal conditions for microbial growth, we also hypothesized increased microbial metabolic quotients (soil respiration per unit of microbial biomass), which is associated with increases in the relative amount of C invested into catabolic pathways along the warming gradient. Soil respiration and basal respiration rates decreased with soil warming intensity, in parallel with a decline in soil C availability. Contrasting to our first hypothesis, we did not detect changes in the temperature sensitivity of soil respiration with soil warming or on the availability of nutrients and of labile C substrates at the time of incubation. However, in agreement to our second hypothesis, microbial metabolic quotients (soil respiration per unit of microbial biomass) increased at warmer temperatures, while the C retained in biomass decreased as substrate became limiting. Long-term (7 years) temperature increases thus triggered a change in the metabolic functioning of the soil microbial communities towards increasing energy costs for maintenance or resource acquisition, thereby lowering the capacity of C retention and stabilization of warmed soils. These results highlight the need

  15. Temperature response of respiration across heterogeneous microtopography in the Arctic tundra, Utqiaġvik, Alaska

    Science.gov (United States)

    Wilkman, E.; Zona, D.; Tang, Y.; Gioli, B.; Lipson, D.; Oechel, W. C.

    2017-12-01

    The response of ecosystem respiration to warming in the Arctic is not well constrained, partly due to the presence of ice-wedge polygons in continuous permafrost areas. These formations lead to substantial variation in vegetation, soil moisture, water table, and active layer depth over the meter scale that can drive respiratory carbon loss. Accurate calculations of in-situ temperature sensitivities (Q10) are vital for the prediction of future Arctic emissions, and while the eddy covariance technique has commonly been used to determine the diurnal and season patterns of net ecosystem exchange (NEE) of CO2, the lack of suitable dark periods in the Arctic summer has limited our ability to estimate and interpret ecosystem respiration. To therefore improve our understanding of and define controls on ecosystem respiration, we directly compared CO2 fluxes measured from automated chambers across the main local polygonised landscape forms (high and low centers, polygon rims, and polygon troughs) to estimates from an adjacent eddy covariance tower. Low-centered polygons and polygon troughs had the greatest cumulative respiration rates, and ecosystem type appeared to be the most important explanatory variable for these rates. Despite the difference in absolute respiration rates, Q10 was surprisingly similar across all microtopographic features, despite contrasting water levels and vegetation types. Conversely, Q10 varied temporally, with higher values during the early and late summer and lower values during the peak growing season. Finally, good agreement was found between chamber and tower based Q10 estimates during the peak growing season. Overall, this study suggests that it is possible to simplify estimates of the temperature sensitivity of respiration across heterogeneous landscapes, but that seasonal changes in Q10 should be incorporated into current and future model simulations.

  16. Human PD-1 binds differently to its human ligands: a comprehensive modeling study.

    Science.gov (United States)

    Viricel, Clement; Ahmed, Marawan; Barakat, Khaled

    2015-04-01

    Programmed death-1 (PD-1) is a potent inhibitory receptor of T cells which binds to two different ligands, namely PD-L1 and PD-L2, and upon binding, it inhibits T cell activation, differentiation, and proliferation, leading to a state of immune tolerance. Blocking these interactions recently emerged as a 'game changer' approach in immunotherapy. Despite the significant therapeutic potential of targeting the PD-1 pathway, the interaction between human PD-1 and its two human ligands is not fully understood. Current crystal structures describe the interactions of mouse PD-1 with human PD-L1 or mouse PD-L2. However, recent mutational and nuclear magnetic resonance (NMR) analyses suggest that human PD-1 binds its human ligands differently compared to their mouse counterparts. No detailed model is currently available to consistently fit these data. The lack of these accurate structures constitutes a high barrier against rationally developing more effective and safer agents targeting these interactions. Here we describe for the first time two accurate models for human PD-1 bound to its two human ligands. Our methodology involved combining molecular dynamics (MD) simulations with protein-protein docking and binding energy analysis to predict the most probable binding conformations for PD1 to its ligands. Our results confirm the available experimental NMR and mutational data and reveal the most accurate atomistic details so far of how human PD-1 binds to human PD-Ls and why the two ligands bind with different affinities to the same receptor. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Soil Respiration in Eddy Covariance Footprints using Forced Diffusion

    Science.gov (United States)

    Nickerson, N.; Gabriel, C. E.; Creelman, C.

    2016-12-01

    Eddy covariance (EC) has been widely used across the globe for more than 20 years, offering researchers invaluable measurements of parameters including Net Ecosystem Exchange and ecosystem respiration. However, research suggests that EC assumptions and technical obstacles can cause biased gas exchange estimates. Measurements of soil respiration (RS) at the ground level may help alleviate these biases; for example, by allowing researchers to reconcile nocturnal EC flux data with RS or by providing a means to inform gap-filling models. RS measurements have been used sparingly alongside EC towers because of the large cost required to scale chamber systems to the EC footprint and data integration and processing burdens. Here we present the Forced Diffusion (FD) method for the measurement of RS at EC sites. The FD method allows for inexpensive and autonomous measurements, providing a scalable approach to matching the EC footprint compared to other RS systems. A pilot study at the Howland Forest AmeriFlux site was carried out from July 15, 2016 to Dec., 2016 using EC, custom-made automated chambers, and FD chambers in tandem. These results emphasize how RS measurements, like those from the eosFD, can identify decoupling of above and below canopy air masses and assist in informing and parameterizing gap-filling techniques. Uncertainty in nocturnal EC fluxes has been extensively characterized at Howland Forest with EC measurements spanning more than 20 years. Similarly, long term automated measurements of RS are also made at Howland, and have already been used to inform EC gap-filling models, making Howland the ideal site for such a study. This study has been designed to reproduce previous findings from Howland using the FD approach, aiming to demonstrate that the measurements taken using the eosFD correlate well with the existing chamber systems and can be used with equal efficacy to inform gap filling models or for other other eddy covariance QA/QC procedures, including

  18. Tillage Effects on Soil Properties & Respiration

    Science.gov (United States)

    Rusu, Teodor; Bogdan, Ileana; Moraru, Paula; Pop, Adrian; Duda, Bogdan; Cacovean, Horea; Coste, Camelia

    2015-04-01

    Soil tillage systems can be able to influence soil compaction, water dynamics, soil temperature and soil structural condition. These processes can be expressed as changes of soil microbiological activity, soil respiration and sustainability of agriculture. Objectives of this study were: 1) to assess the effects of tillage systems (Conventional System-CS, Minimum Tillage-MT, No-Tillage-NT) on soil compaction, soil temperature, soil moisture and soil respiration and 2) to establish the relationship that exists in changing soil properties. Three treatments were installed: CS-plough + disc; MT-paraplow + rotary grape; NT-direct sowing. The study was conducted on an Argic-Stagnic Faeoziom. The MT and NT applications reduce or completely eliminate the soil mobilization, due to this, soil is compacted in the first year of application. The degree of compaction is directly related to soil type and its state of degradation. The state of soil compaction diminished over time, tending toward a specific type of soil density. Soil moisture was higher in NT and MT at the time of sowing and in the early stages of vegetation and differences diminished over time. Moisture determinations showed statistically significant differences. The MT and NT applications reduced the thermal amplitude in the first 15 cm of soil depth and increased the soil temperature by 0.5-2.20C. The determinations confirm the effect of soil tillage system on soil respiration; the daily average was lower at NT (315-1914 mmoli m-2s-1) and followed by MT (318-2395 mmoli m-2s-1) and is higher in the CS (321-2480 mmol m-2s-1). Comparing with CS, all the two conservation tillage measures decreased soil respiration, with the best effects of no-tillage. An exceeding amount of CO2 produced in the soil and released into the atmosphere, resulting from aerobic processes of mineralization of organic matter (excessive loosening) is considered to be not only a way of increasing the CO2 in the atmosphere, but also a loss of

  19. Age and gender specific biokinetic model for strontium in humans

    Energy Technology Data Exchange (ETDEWEB)

    Shagina, N. B.; Tolstykh, E. I.; Degteva, M. O.; Anspaugh, L. R.; Napier, Bruce A.

    2015-03-01

    A biokinetic model for strontium in humans is necessary for quantification of internal doses due to strontium radioisotopes. The ICRP-recommended biokinetic model for strontium has limitation for use in a population study, because it is not gender specific and does not cover all age ranges. The extensive Techa River data set on 90Sr in humans (tens of thousands of measurements) is a unique source of data on long-term strontium retention for men and women of all ages at intake. These, as well as published data, were used for evaluation of age- and gender-specific parameters for a new compartment biokinetic model for strontium (Sr-AGe model). The Sr-AGe model has similar structure as the ICRP model for the alkaline earth elements. The following parameters were mainly reevaluated: gastro-intestinal absorption and parameters related to the processes of bone formation and resorption defining calcium and strontium transfers in skeletal compartments. The Sr-AGe model satisfactorily describes available data sets on strontium retention for different kinds of intake (dietary and intravenous) at different ages (0–80 years old) and demonstrates good agreement with data sets for different ethnic groups. The Sr-AGe model can be used for dose assessment in epidemiological studies of general population exposed to ingested strontium radioisotopes.

  20. A review on otolith models in human perception.

    Science.gov (United States)

    Asadi, Houshyar; Mohamed, Shady; Lim, Chee Peng; Nahavandi, Saeid

    2016-08-01

    The vestibular system, which consists of semicircular canals and otolith, are the main sensors mammals use to perceive rotational and linear motions. Identifying the most suitable and consistent mathematical model of the vestibular system is important for research related to driving perception. An appropriate vestibular model is essential for implementation of the Motion Cueing Algorithm (MCA) for motion simulation purposes, because the quality of the MCA is directly dependent on the vestibular model used. In this review, the history and development process of otolith models are presented and analyzed. The otolith organs can detect linear acceleration and transmit information about sensed applied specific forces on the human body. The main purpose of this review is to determine the appropriate otolith models that agree with theoretical analyses and experimental results as well as provide reliable estimation for the vestibular system functions. Formulating and selecting the most appropriate mathematical model of the vestibular system is important to ensure successful human perception modelling and simulation when implementing the model into the MCA for motion analysis. Copyright © 2016 Elsevier B.V. All rights reserved.