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Sample records for spontaneous firing rates

  1. Interesting spontaneous combustion fire at Haus Aden colliery

    Energy Technology Data Exchange (ETDEWEB)

    Both, W; Weinheimer, O

    1976-02-05

    Spontaneous combustion ahead of the face occurred in an over-worked and under-worked seam. When the first cavity containing hot ash was found, an attempt to extinguish the fire with water was abandoned because of the quantity of steam produced, but the fire was extinguished by covering it with paste containing magnesium chloride and hydroxide and calcium chloride. Mining operations continued while the coal surrounding the hot region was cooled with water. The steps taken to detect and deal with other fires in advance of the face are described. These included pre-infusion with calcium chloride solution via boreholes and treatment of the hot cavities encountered with magnesium chloride paste. This method of fire-fighting was more successful than the use of water alone.

  2. Spontaneous mutation rates and the rate-doubling dose

    International Nuclear Information System (INIS)

    Von Borstel, R.C.; Moustaccki, E.; Latarjet, R.

    1978-01-01

    The amount of radiation required to double the frequency of mutations or tumours over the rate of those that occur spontaneously is called the rate-doubling dose. An equivalent concept has been proposed for exposure to other environmental mutagens. The doubling dose concept is predicated on the assumption that all human populations have the same spontaneous mutation rate, and that this spontaneous mutation rate is known. It is now established for prokaryotes and lower eukaryotes that numerous genes control the spontaneous mutation rate, and it is likely that the same is true for human cells as well. Given that the accepted mode of evolution of human populatons is from small, isolated groups of individuals, it seems likely that each population would have a different spontaneous mutation rate. Given that a minimum of twenty genes control or affect the spontaneous mutation rate, and that each of these in turn is susceptible to spontaneously arising or environmentally induced mutations, it seems likely that every individual within a population (except for siblings from identical multiple births) will have a unique spontaneous mutation rate. If each individual in a population does have a different spontaneous mutation rate, the doubling dose concept, in rigorous terms, is fallacious. Therefore, as with other concepts of risk evaluation, the doubling dose concept is subject to criticism. Nevertheless, until we know individual spontaneous mutation rates with precision, and can evaluate risks based on this information, the doubling dose concept has a heuristic value and is needed for practical assessment of risks for defined populations. (author)

  3. FIRES: Fire Information Retrieval and Evaluation System - A program for fire danger rating analysis

    Science.gov (United States)

    Patricia L. Andrews; Larry S. Bradshaw

    1997-01-01

    A computer program, FIRES: Fire Information Retrieval and Evaluation System, provides methods for evaluating the performance of fire danger rating indexes. The relationship between fire danger indexes and historical fire occurrence and size is examined through logistic regression and percentiles. Historical seasonal trends of fire danger and fire occurrence can be...

  4. Fire characteristics charts for fire behavior and U.S. fire danger rating

    Science.gov (United States)

    Faith Ann Heinsch; Pat Andrews

    2010-01-01

    The fire characteristics chart is a graphical method of presenting U.S. National Fire Danger Rating indices or primary surface or crown fire behavior characteristics. A desktop computer application has been developed to produce fire characteristics charts in a format suitable for inclusion in reports and presentations. Many options include change of scales, colors,...

  5. Metabolism regulates the spontaneous firing of substantia nigra pars reticulata neurons via KATP and nonselective cation channels.

    Science.gov (United States)

    Lutas, Andrew; Birnbaumer, Lutz; Yellen, Gary

    2014-12-03

    Neurons use glucose to fuel glycolysis and provide substrates for mitochondrial respiration, but neurons can also use alternative fuels that bypass glycolysis and feed directly into mitochondria. To determine whether neuronal pacemaking depends on active glucose metabolism, we switched the metabolic fuel from glucose to alternative fuels, lactate or β-hydroxybutyrate, while monitoring the spontaneous firing of GABAergic neurons in mouse substantia nigra pars reticulata (SNr) brain slices. We found that alternative fuels, in the absence of glucose, sustained SNr spontaneous firing at basal rates, but glycolysis may still be supported by glycogen in the absence of glucose. To prevent any glycogen-fueled glycolysis, we directly inhibited glycolysis using either 2-deoxyglucose or iodoacetic acid. Inhibiting glycolysis in the presence of alternative fuels lowered SNr firing to a slower sustained firing rate. Surprisingly, we found that the decrease in SNr firing was not mediated by ATP-sensitive potassium (KATP) channel activity, but if we lowered the perfusion flow rate or omitted the alternative fuel, KATP channels were activated and could silence SNr firing. The KATP-independent slowing of SNr firing that occurred with glycolytic inhibition in the presence of alternative fuels was consistent with a decrease in a nonselective cationic conductance. Although mitochondrial metabolism alone can prevent severe energy deprivation and KATP channel activation in SNr neurons, active glucose metabolism appears important for keeping open a class of ion channels that is crucial for the high spontaneous firing rate of SNr neurons. Copyright © 2014 the authors 0270-6474/14/3416336-12$15.00/0.

  6. Cold Climate Structural Fire Danger Rating System?

    Directory of Open Access Journals (Sweden)

    Maria-Monika Metallinou

    2018-03-01

    Full Text Available Worldwide, fires kill 300,000 people every year. The fire season is usually recognized to be in the warmer periods of the year. Recent research has, however, demonstrated that the colder season also has major challenges regarding severe fires, especially in inhabited (heated wood-based structures in cold-climate areas. Knowledge about the effect of dry cellulose-based materials on fire development, indoor and outdoor, is a motivation for monitoring possible changes in potential fire behavior and associated fire risk. The effect of wind in spreading fires to neighboring structures points towards using weather forecasts as information on potential fire spread behavior. As modern weather forecasts include temperature and relative humidity predictions, there may already be sufficient information available to develop a structural fire danger rating system. Such a system may include the following steps: (1 Record weather forecasts and actual temperature and relative humidity inside and outside selected structures; (2 Develop a meteorology-data-based model to predict indoor relative humidity levels; (3 Perform controlled drying chamber experiments involving typical hygroscopic fire fuel; (4 Compare the results to the recorded values in selected structures; and (5 Develop the risk model involving the results from drying chamber experiments, weather forecasts, and separation between structures. Knowledge about the structures at risk and their use is also important. The benefits of an automated fire danger rating system would be that the society can better plan for potentially severe cold-climate fires and thereby limit the negative impacts of such fires.

  7. Noise in attractor networks in the brain produced by graded firing rate representations.

    Directory of Open Access Journals (Sweden)

    Tristan J Webb

    Full Text Available Representations in the cortex are often distributed with graded firing rates in the neuronal populations. The firing rate probability distribution of each neuron to a set of stimuli is often exponential or gamma. In processes in the brain, such as decision-making, that are influenced by the noise produced by the close to random spike timings of each neuron for a given mean rate, the noise with this graded type of representation may be larger than with the binary firing rate distribution that is usually investigated. In integrate-and-fire simulations of an attractor decision-making network, we show that the noise is indeed greater for a given sparseness of the representation for graded, exponential, than for binary firing rate distributions. The greater noise was measured by faster escaping times from the spontaneous firing rate state when the decision cues are applied, and this corresponds to faster decision or reaction times. The greater noise was also evident as less stability of the spontaneous firing state before the decision cues are applied. The implication is that spiking-related noise will continue to be a factor that influences processes such as decision-making, signal detection, short-term memory, and memory recall even with the quite large networks found in the cerebral cortex. In these networks there are several thousand recurrent collateral synapses onto each neuron. The greater noise with graded firing rate distributions has the advantage that it can increase the speed of operation of cortical circuitry.

  8. TETRAMETHRIN AND DDT INHIBIT SPONTANEOUS FIRING IN CORTICAL NEURONAL NETWORKS

    Science.gov (United States)

    The insecticidal and neurotoxic effects of pyrethroids result from prolonged sodium channel inactivation, which causes alterations in neuronal firing and communication. Previously, we determined the relative potencies of 11 type I and type II pyrethroid insecticides using microel...

  9. Firing probability and mean firing rates of human muscle vasoconstrictor neurones are elevated during chronic asphyxia

    DEFF Research Database (Denmark)

    Ashley, Cynthia; Burton, Danielle; Sverrisdottir, Yrsa B

    2010-01-01

    in the obstructive sleep apnoea syndrome (OSAS) is associated with an increase in firing probability and mean firing rate, and an increase in multiple within-burst firing. Here we characterize the firing properties of muscle vasoconstrictor neurones in patients with chronic obstructive pulmonary disease (COPD), who...... are chronically asphyxic. We tested the hypothesis that this elevated chemical drive would shift the firing pattern from that seen in healthy subjects to that seen in OSAS. The mean firing probability (52%) and mean firing rate (0.92 Hz) of 17 muscle vasoconstrictor neurones recorded in COPD were comparable...

  10. Recurrence rate after thoracoscopic surgery for primary spontaneous pneumothorax.

    Science.gov (United States)

    Dagnegård, Hanna H; Rosén, Alice; Sartipy, Ulrik; Bergman, Per

    2017-08-01

    There is an on-going discussion regarding the recurrence rate after surgery for primary spontaneous pneumothorax by video assisted thoracic surgery (VATS) or by thoracotomy access. This study aimed to describe the recurrence rate, and to identify a possible learning curve, following surgery for primary spontaneous pneumothorax by VATS. All patients who underwent surgery for primary spontaneous pneumothorax by VATS at Karolinska University Hospital 2004-2013 were reviewed. Preoperative and operative characteristics were obtained from medical records. Patients were followed-up through telephone interviews or questionnaires and by review of medical records. The primary outcome of interest was time to recurrence of pneumothorax requiring intervention. Outcomes were compared between patients operated during 2004-June 2010 and July 2010-2013. 219 patients who underwent 234 consecutive procedures were included. The mean follow-up times were 6.3 and 2.9 years in the early and late period, respectively. The postoperative recurrence rate in the early period was 16% (11%-25%), 18% (12%-27%), and 18% (12%-27%), at 1, 3 and 5 years, compared to 1.7% (0.4%-6.8%), 7.6% (3.7%-15%), and 9.8% (4.8%-19%) at 1, 3 and 5 years, in the late period (p = 0.016). We found that the recurrence rate after thoracoscopic surgery for primary spontaneous pneumothorax decreased significantly during the study period. Our results strongly suggest that thoracoscopic surgery for pneumothorax involve a substantial learning curve.

  11. Accuracy of rate coding: When shorter time window and higher spontaneous activity help

    Czech Academy of Sciences Publication Activity Database

    Leváková, Marie; Tamborrino, M.; Košťál, Lubomír; Lánský, Petr

    2017-01-01

    Roč. 95, č. 2 (2017), č. článku 022310. ISSN 2470-0045 R&D Projects: GA ČR(CZ) GA15-08066S; GA MŠk(CZ) 7AMB17AT048 Institutional support: RVO:67985823 Keywords : rate coding * observation window * spontaneous activity * Fisher information * perfect integrate- and -fire model * Wiener process Subject RIV: BB - Applied Statistics, Operational Research OBOR OECD: Biology (theoretical, mathematical, thermal, cryobiology, biological rhythm), Evolutionary biology Impact factor: 2.366, year: 2016

  12. Inhibition Effect of Phosphorus Flame Retardants on the Fire Disasters Induced by Spontaneous Combustion of Coal

    Directory of Open Access Journals (Sweden)

    Yibo Tang

    2017-01-01

    Full Text Available Coal spontaneous combustion (CSC generally induces fire disasters in underground mines, thus causing serious casualties, environmental pollution, and property loss around the world. By using six P-containing additives to process three typical coal samples, this study investigated the variations of the self-ignition characteristics of the coal samples before and after treatment. The analysis was performed by combining thermogravimetric analysis/differential scanning calorimetry (TG/DSC Fourier transform infrared spectrometer (FTIR and low temperature oxidation. Experimental results showed that P-containing inhibitors could effectively restrain the heat emitted in the combustion of coal samples and therefore the ignition temperature of the coal samples was delayed at varying degrees. The combustion rate of the coal samples was reduced as well. At the temperatures ranging from 50°C to 150°C, the activation energy of the coal samples after the treatment was found to increase, which indicated that the coal samples were more difficult to be oxidized. After being treated with phosphorus flame retardants (PFRs, the content of several active groups represented by the C-O structure in the three coal samples was proved to be obviously changed. This suggested that PFRs could significantly inhibit the content of CO generated by the low temperature oxidation of coal, and the flame-retardant efficiency grew with the increasing temperature. At 200°C, the maximal inhibition efficiency reached approximately 85%.

  13. Real-time relationship between PKA biochemical signal network dynamics and increased action potential firing rate in heart pacemaker cells

    Science.gov (United States)

    Yaniv, Yael; Ganesan, Ambhighainath; Yang, Dongmei; Ziman, Bruce D.; Lyashkov, Alexey E.; Levchenko, Andre; Zhang, Jin; Lakatta, Edward G.

    2015-01-01

    cAMP-PKA protein kinase is a key nodal signaling pathway that regulates a wide range of heart pacemaker cell functions. These functions are predicted to be involved in regulation of spontaneous action potential (AP) generation of these cells. Here we investigate if the kinetics and stoichiometry of increase in PKA activity match the increase in AP firing rate in response to β-adrenergic receptor (β-AR) stimulation or phosphodiesterase (PDE) inhibition, that alter the AP firing rate of heart sinoatrial pacemaker cells. In cultured adult rabbit pacemaker cells infected with an adenovirous expressing the FRET sensor AKAR3, the EC50 in response to graded increases in the intensity of β-AR stimulation (by Isoproterenol) the magnitude of the increases in PKA activity and the spontaneous AP firing rate were similar (0.4±0.1nM vs. 0.6±0.15nM, respectively). Moreover, the kinetics (t1/2) of the increases in PKA activity and spontaneous AP firing rate in response to β-AR stimulation or PDE inhibition were tightly linked. We characterized the system rate-limiting biochemical reactions by integrating these experimentally derived data into mechanistic-computational model. Model simulations predicted that phospholamban phosphorylation is a potent target of the increase in PKA activity that links to increase in spontaneous AP firing rate. In summary, the kinetics and stoichiometry of increases in PKA activity in response to a physiological (β-AR stimulation) or pharmacological (PDE inhibitor) stimuli match those of changes in the AP firing rate. Thus Ca2+-cAMP/PKA-dependent phosphorylation limits the rate and magnitude of increase in spontaneous AP firing rate. PMID:26241846

  14. Firing patterns of spontaneously active motor units in spinal cord-injured subjects.

    Science.gov (United States)

    Zijdewind, Inge; Thomas, Christine K

    2012-04-01

    Involuntary motor unit activity at low rates is common in hand muscles paralysed by spinal cord injury. Our aim was to describe these patterns of motor unit behaviour in relation to motoneurone and motor unit properties. Intramuscular electromyographic activity (EMG), surface EMG and force were recorded for 30 min from thenar muscles of nine men with chronic cervical SCI. Motor units fired for sustained periods (>10 min) at regular (coefficient of variation ≤ 0.15, CV, n =19 units) or irregular intervals (CV>0.15, n =14). Regularly firing units started and stopped firing independently suggesting that intrinsic motoneurone properties were important for recruitment and derecruitment. Recruitment (3.6 Hz, SD 1.2), maximal (10.2 Hz, SD 2.3, range: 7.5-15.4 Hz) and derecruitment frequencies were low (3.3 Hz, SD 1.6), as were firing rate increases after recruitment (~20 intervals in 3 s). Once active, firing often covaried, promoting the idea that units received common inputs.Half of the regularly firing units showed a very slow decline (>40 s) in discharge before derecruitment and had interspike intervals longer than their estimated after hyperpolarisation potential (AHP) duration (estimated by death rate and breakpoint analyses). The other units were derecruited more abruptly and had shorter estimated AHP durations. Overall, regularly firing units had longer estimated AHP durations and were weaker than irregularly firing units, suggesting they were lower threshold units. Sustained firing of units at regular rates may reflect activation of persistent inward currents, visible here in the absence of voluntary drive, whereas irregularly firing units may only respond to synaptic noise.

  15. Tapping Into Rate Flexibility: Musical Training Facilitates Synchronization Around Spontaneous Production Rates

    Directory of Open Access Journals (Sweden)

    Rebecca Scheurich

    2018-04-01

    Full Text Available The ability to flexibly adapt one’s behavior is critical for social tasks such as speech and music performance, in which individuals must coordinate the timing of their actions with others. Natural movement frequencies, also called spontaneous rates, constrain synchronization accuracy between partners during duet music performance, whereas musical training enhances synchronization accuracy. We investigated the combined influences of these factors on the flexibility with which individuals can synchronize their actions with sequences at different rates. First, we developed a novel musical task capable of measuring spontaneous rates in both musicians and non-musicians in which participants tapped the rhythm of a familiar melody while hearing the corresponding melody tones. The novel task was validated by similar measures of spontaneous rates generated by piano performance and by the tapping task from the same pianists. We then implemented the novel task with musicians and non-musicians as they synchronized tapping of a familiar melody with a metronome at their spontaneous rates, and at rates proportionally slower and faster than their spontaneous rates. Musicians synchronized more flexibly across rates than non-musicians, indicated by greater synchronization accuracy. Additionally, musicians showed greater engagement of error correction mechanisms than non-musicians. Finally, differences in flexibility were characterized by more recurrent (repetitive and patterned synchronization in non-musicians, indicative of greater temporal rigidity.

  16. Tapping Into Rate Flexibility: Musical Training Facilitates Synchronization Around Spontaneous Production Rates

    Science.gov (United States)

    Scheurich, Rebecca; Zamm, Anna; Palmer, Caroline

    2018-01-01

    The ability to flexibly adapt one’s behavior is critical for social tasks such as speech and music performance, in which individuals must coordinate the timing of their actions with others. Natural movement frequencies, also called spontaneous rates, constrain synchronization accuracy between partners during duet music performance, whereas musical training enhances synchronization accuracy. We investigated the combined influences of these factors on the flexibility with which individuals can synchronize their actions with sequences at different rates. First, we developed a novel musical task capable of measuring spontaneous rates in both musicians and non-musicians in which participants tapped the rhythm of a familiar melody while hearing the corresponding melody tones. The novel task was validated by similar measures of spontaneous rates generated by piano performance and by the tapping task from the same pianists. We then implemented the novel task with musicians and non-musicians as they synchronized tapping of a familiar melody with a metronome at their spontaneous rates, and at rates proportionally slower and faster than their spontaneous rates. Musicians synchronized more flexibly across rates than non-musicians, indicated by greater synchronization accuracy. Additionally, musicians showed greater engagement of error correction mechanisms than non-musicians. Finally, differences in flexibility were characterized by more recurrent (repetitive) and patterned synchronization in non-musicians, indicative of greater temporal rigidity. PMID:29681872

  17. How to reduce your fire insurance rates

    Science.gov (United States)

    Dubain, M.

    1971-01-01

    Construction procedures and utilization of materials to reduce the cost of insuring large buildings against losses from fire are discussed. Examples of good and bad techniques in building construction and fire safety management are provided. The inadequacies of building codes and the hazards resulting from improper construction are examined.

  18. Reduction in spontaneous firing of mouse excitatory layer 4 cortical neurons following visual classical conditioning

    Science.gov (United States)

    Bekisz, Marek; Shendye, Ninad; Raciborska, Ida; Wróbel, Andrzej; Waleszczyk, Wioletta J.

    2017-08-01

    The process of learning induces plastic changes in neuronal network of the brain. Our earlier studies on mice showed that classical conditioning in which monocular visual stimulation was paired with an electric shock to the tail enhanced GABA immunoreactivity within layer 4 of the monocular part of the primary visual cortex (V1), contralaterally to the stimulated eye. In the present experiment we investigated whether the same classical conditioning paradigm induces changes of neuronal excitability in this cortical area. Two experimental groups were used: mice that underwent 7-day visual classical conditioning and controls. Patch-clamp whole-cell recordings were performed from ex vivo slices of mouse V1. The slices were perfused with the modified artificial cerebrospinal fluid, the composition of which better mimics the brain interstitial fluid in situ and induces spontaneous activity. The neuronal excitability was characterized by measuring the frequency of spontaneous action potentials. We found that layer 4 star pyramidal cells located in the monocular representation of the "trained" eye in V1 had lower frequency of spontaneous activity in comparison with neurons from the same cortical region of control animals. Weaker spontaneous firing indicates decreased general excitability of star pyramidal neurons within layer 4 of the monocular representation of the "trained" eye in V1. Such effect could result from enhanced inhibitory processes accompanying learning in this cortical area.

  19. Estimating spontaneous mutation rates at enzyme loci in Drosophila melanogaster

    International Nuclear Information System (INIS)

    Mukai, Terumi; Yamazaki, Tsuneyuki; Harada, Ko; Kusakabe, Shin-ichi

    1990-04-01

    Spontaneous mutations were accumulated for 1,620,826 allele-generations on chromosomes that originated from six stem second chromosomes of Drosophila melanogaster. Only null-electromorph mutations were detected. Band-electromorph mutations were not found. The average rate of null-electromorph mutations was 2.71 x 10 -5 per locus per generation. The 95% confidence interval (μ n ) was 1.97 x 10 -5 n -5 per locus per generation. The upper 95% confidence limit of the band-electromorph mutation rate (μ B ) was 2.28 x 10 -6 per locus per generation. It appeared that null mutations were induced by movable genetic elements and that the mutation rates were different from chromosome to chromosome. (author)

  20. A fire danger rating system for Hawaii

    Science.gov (United States)

    Robert E. Burgan; Francis M. Fujioka; George H. Hirata

    1974-01-01

    Extremes in rainfall on the Hawaiian Islands make it difficult to judge forest fire danger conditions. The use of an automatic data collection and computer processing system helps to monitor the problem.

  1. How much do we know about spontaneous human mutation rates

    Energy Technology Data Exchange (ETDEWEB)

    Crow, J.F. (Univ. of Wisconsin, Madison, WI (United States))

    1993-01-01

    The much larger number of cell divisions between zygote and sperm than between zygote and egg, the increased age of fathers of children with new dominant mutations, and the greater evolution rate of pseudogenes on the Y chromosome than of those on autosomes all point to a much higher mutation rate in human males than in females, as first pointed out by Haldane in his classical study of X-linked hemophilia. The age of the father is the main factor determining the human spontaneous mutation rate, and probably the total mutation rate. The total mutation rate in Drosophila males of genes causing minor reduction in viability is at least 0.4 per sperm and may be considerably higher. The great mutation load implied by a rate of [approx] 1 per zygote can be greatly ameliorated by quasi-transition selection. Corresponding data are not available for the human population. The evolution rate of pseudogenes in primates suggests some 10[sup 2] new mutations per zygote. Presumably the overwhelming majority of these are neutral, but even the approximate fraction is not known. Statistical evidence in Drosophilia shows that mutations with minor effects cause about the same heterozygous impairment of fitness as those that are lethal when homozygous. The magnitude of heterozygous effect is such that almost all mutant genes are eliminated as heterozygotes before ever becoming homozygous. Although quantitative data in the human species are lacking, anecdotal information supports the conclusion that partial dominance is the rule here as well. This suggests that if the human mutation rate were increased or decreased, the effects would be spread over a period of 50-100 generations. 31 refs., 3 figs., 2 tabs.

  2. Literature study regarding fire protection in nuclear power plants. Part I: Fire rated separations

    International Nuclear Information System (INIS)

    Isaksson, S.

    1995-06-01

    This literature study has been made on behalf of the Swedish Nuclear Power Inspectorate. The aim is to describe different aspects of fire protection in nuclear power plants. Conventional building codes can not give guidance on where to make fire rated separations in order to separate redundant trains of safety systems. The separation must originate in functional demands from the authorities on what functions are essential during and after a fire, and under what circumstances these functions shall be retained, i.e. the number of independent faults and initiating events. As a basic demand it is suggested to rate the strength of separations according to conventional building code, based on fire load. The whole separating construction shall have the same fire rating, including the ventilation system. Deviations from the basic demand can de done in case it can be proven that it is possible to compensate some or all of the fire rating with other measures. There is a general lack of statistical information regarding the reliability of fire separating constructions such as walls, fire doors, penetration seals and fire dampers. The amount of cables penetrating a seal is in many cases much higher in real installations than what has been tested for type approval. It would therefore be valuable to perform a furnace test with a more representative amount of cables passing through a penetration seal. Tests have shown that the 20 foot horizontal separation distance stipulated by NRC is not a guarantee against fire damage. Spatial separations based on general requirements shall not be allowed, but considered from case to case based on actual circumstances. For fire protection by isolation or coatings, it is of great importance to choose the method of protection carefully, to be compatible with the material it shall be applied on, and the environment and types of fire that may occur. 48 refs, 2 figs, 5 tabs

  3. The rate of spontaneous mutations in human myeloid cells

    International Nuclear Information System (INIS)

    Araten, David J.; Krejci, Ondrej; DiTata, Kimberly; Wunderlich, Mark; Sanders, Katie J.; Zamechek, Leah; Mulloy, James C.

    2013-01-01

    Highlights: • We provide the first measurement of the mutation rate (μ) in human myeloid cells. • μ is measured to be 3.6–23 × 10 −7 per cell division. • The AML-ETO and MLL-AF9 fusions do not seem to increase μ. • Cooperating mutations in NRAS, FLT3 and p53 not seem to increase μ. • Hypermutability may be required to explain leukemogenesis. - Abstract: The mutation rate (μ) is likely to be a key parameter in leukemogenesis, but historically, it has been difficult to measure in humans. The PIG-A gene has some advantages for the detection of spontaneous mutations because it is X-linked, and therefore only one mutation is required to disrupt its function. Furthermore, the PIG-A-null phenotype is readily detected by flow cytometry. Using PIG-A, we have now provided the first in vitro measurement of μ in myeloid cells, using cultures of CD34+ cells that are transduced with either the AML-ETO or the MLL-AF9 fusion genes and expanded with cytokines. For the AML-ETO cultures, the median μ value was ∼9.4 × 10 −7 (range ∼3.6–23 × 10 −7 ) per cell division. In contrast, few spontaneous mutations were observed in the MLL-AF9 cultures. Knockdown of p53 or introduction of mutant NRAS or FLT3 alleles did not have much of an effect on μ. Based on these data, we provide a model to predict whether hypermutability must occur in the process of leukemogenesis

  4. The cluster analysis based on non-teacher artificial neural network for the danger prediction of coal spontaneous fire

    Energy Technology Data Exchange (ETDEWEB)

    Wang, D.; Wang, J. [China University of Mining and Technology (China)

    1999-04-01

    This paper focuses on the problem of predicting the danger level of spontaneous fire in coal mines. Firstly, the inadequacy of the present artificial neural networks prediction model is analysed. Then a new cluster model based on non-teacher neural network is constructed according to the danger judgement standards given by experts. On this basis, by adopting the error square sum criterion and its algorithm, the corresponding prediction software is developed and applied in two working faces of Chaili Coal Mine. The forecasting result is importantly significant for the prevention of spontaneous fire. 4 refs., 1 fig., 1 tab.

  5. Coal-Fired Power Plant Heat Rate Reductions

    Science.gov (United States)

    View a report that identifies systems and equipment in coal-fired power plants where efficiency improvements can be realized, and provides estimates of the resulting net plant heat rate reductions and costs for implementation.

  6. Effects of meditation practice on spontaneous eyeblink rate.

    Science.gov (United States)

    Kruis, Ayla; Slagter, Heleen A; Bachhuber, David R W; Davidson, Richard J; Lutz, Antoine

    2016-05-01

    A rapidly growing body of research suggests that meditation can change brain and cognitive functioning. Yet little is known about the neurochemical mechanisms underlying meditation-related changes in cognition. Here, we investigated the effects of meditation on spontaneous eyeblink rates (sEBR), a noninvasive peripheral correlate of striatal dopamine activity. Previous studies have shown a relationship between sEBR and cognitive functions such as mind wandering, cognitive flexibility, and attention-functions that are also affected by meditation. We therefore expected that long-term meditation practice would alter eyeblink activity. To test this, we recorded baseline sEBR and intereyeblink intervals (IEBI) in long-term meditators (LTM) and meditation-naive participants (MNP). We found that LTM not only blinked less frequently, but also showed a different eyeblink pattern than MNP. This pattern had good to high degree of consistency over three time points. Moreover, we examined the effects of an 8-week course of mindfulness-based stress reduction on sEBR and IEBI, compared to an active control group and a waitlist control group. No effect of short-term meditation practice was found. Finally, we investigated whether different types of meditation differentially alter eyeblink activity by measuring sEBR and IEBI after a full day of two kinds of meditation practices in the LTM. No effect of meditation type was found. Taken together, these findings may suggest either that individual difference in dopaminergic neurotransmission is a self-selection factor for meditation practice, or that long-term, but not short-term meditation practice induces stable changes in baseline striatal dopaminergic functioning. © 2016 Society for Psychophysiological Research.

  7. MOTOR UNIT FIRING RATES DURING SPASMS IN THENAR MUSCLES OF SPINAL CORD INJURED SUBJECTS

    Directory of Open Access Journals (Sweden)

    Inge eZijdewind

    2014-11-01

    Full Text Available Abstract Involuntary contractions of paralyzed muscles (spasms commonly disrupt daily activities and rehabilitation after human spinal cord injury. Our aim was to examine the recruitment, firing rate modulation, and derecruitment of motor units that underlie spasms of thenar muscles after cervical spinal cord injury. Intramuscular electromyographic activity (EMG, surface EMG, and force were recorded during thenar muscle spasms that occurred spontaneously or that were triggered by movement of a shoulder or leg. Most spasms were submaximal (mean: 39%, SD: 33 of the force evoked by median nerve stimulation at 50 Hz with strong relationships between EMG and force (R2>0.69. Unit recruitment occurred over a wide force range (0.2-103% of 50 Hz force. Significant unit rate modulation occurred during spasms (frequency at 25% maximal force: 8.8 Hz, 3.3 SD; at maximal force: 16.1 Hz, 4.1 SD. Mean recruitment frequency (7.1 Hz, 3.2 SD was significantly higher than derecruitment frequency (5.4 Hz, 2.4 SD. Coactive unit pairs that fired for more than 4 s showed high (R2>0.7, n=4 or low (R2:0.3-0.7, n=12 rate-rate correlations, and derecruitment reversals (21 pairs, 29%. Later recruited units had higher or lower maximal firing rates than lower threshold units. These discrepant data show that coactive motoneurons are driven by both common inputs and by synaptic inputs from different sources during muscle spasms. Further, thenar motoneurons can still fire at high rates in response to various peripheral inputs after spinal cord injury, supporting the idea that low maximal voluntary firing rates and forces in thenar muscles result from reduced descending drive.

  8. Real-time relationship between PKA biochemical signal network dynamics and increased action potential firing rate in heart pacemaker cells: Kinetics of PKA activation in heart pacemaker cells.

    Science.gov (United States)

    Yaniv, Yael; Ganesan, Ambhighainath; Yang, Dongmei; Ziman, Bruce D; Lyashkov, Alexey E; Levchenko, Andre; Zhang, Jin; Lakatta, Edward G

    2015-09-01

    cAMP-PKA protein kinase is a key nodal signaling pathway that regulates a wide range of heart pacemaker cell functions. These functions are predicted to be involved in regulation of spontaneous action potential (AP) generation of these cells. Here we investigate if the kinetics and stoichiometry of increase in PKA activity match the increase in AP firing rate in response to β-adrenergic receptor (β-AR) stimulation or phosphodiesterase (PDE) inhibition, that alters the AP firing rate of heart sinoatrial pacemaker cells. In cultured adult rabbit pacemaker cells infected with an adenovirus expressing the FRET sensor AKAR3, the EC50 in response to graded increases in the intensity of β-AR stimulation (by Isoproterenol) the magnitude of the increases in PKA activity and the spontaneous AP firing rate were similar (0.4±0.1nM vs. 0.6±0.15nM, respectively). Moreover, the kinetics (t1/2) of the increases in PKA activity and spontaneous AP firing rate in response to β-AR stimulation or PDE inhibition were tightly linked. We characterized the system rate-limiting biochemical reactions by integrating these experimentally derived data into a mechanistic-computational model. Model simulations predicted that phospholamban phosphorylation is a potent target of the increase in PKA activity that links to increase in spontaneous AP firing rate. In summary, the kinetics and stoichiometry of increases in PKA activity in response to a physiological (β-AR stimulation) or pharmacological (PDE inhibitor) stimuli match those of changes in the AP firing rate. Thus Ca(2+)-cAMP/PKA-dependent phosphorylation limits the rate and magnitude of increase in spontaneous AP firing rate. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Burning phylogenies: fire, molecular evolutionary rates, and diversification.

    Science.gov (United States)

    Verdú, Miguel; Pausas, Juli G; Segarra-Moragues, José Gabriel; Ojeda, Fernando

    2007-09-01

    Mediterranean-type ecosystems are among the most remarkable plant biodiversity "hot spots" on the earth, and fire has traditionally been invoked as one of the evolutionary forces explaining this exceptional diversity. In these ecosystems, adult plants of some species are able to survive after fire (resprouters), whereas in other species fire kills the adults and populations are only maintained by an effective post-fire recruitment (seeders). Seeders tend to have shorter generation times than resprouters, particularly under short fire return intervals, thus potentially increasing their molecular evolutionary rates and, ultimately, their diversification. We explored whether seeder lineages actually have higher rates of molecular evolution and diversification than resprouters. Molecular evolutionary rates in different DNA regions were compared in 45 phylogenetically paired congeneric taxa from fire-prone Mediterranean-type ecosystems with contrasting seeder and resprouter life histories. Differential diversification was analyzed with both topological and chronological approaches in five genera (Banksia, Daviesia, Lachnaea, Leucadendron, and Thamnochortus) from two fire-prone regions (Australia and South Africa). We found that seeders had neither higher molecular rates nor higher diversification than resprouters. Such lack of differences in molecular rates between seeders and resprouters-which did not agree with theoretical predictions-may occur if (1) the timing of the switch from seeding to resprouting (or vice versa) occurs near the branch tip, so that most of the branch length evolves under the opposite life-history form; (2) resprouters suffer more somatic mutations and therefore counterbalancing the replication-induced mutations of seeders; and (3) the rate of mutations is not related to shorter generation times because plants do not undergo determinate germ-line replication. The absence of differential diversification is to be expected if seeders and resprouters

  10. The burning and smoke release rates of sodium pool fires

    International Nuclear Information System (INIS)

    Newman, R.N.; Payne, J.F.B.

    1976-10-01

    The burning rates and smoke release fractions of sodium pool fires have been measured over the pool temperature range 250 0 C to 750 0 C. A theoretical model is derived which satisfactorily predicts the burning rate over the above temperature range. The theory further predicts that the burning rate should be independent of pool diameter, a prediction supported by a comparison of burning rate data from this study and available data from other studies. (author)

  11. The 1978 National Fire-Danger Rating System: technical documentation

    Science.gov (United States)

    Larry S. Bradshaw; John E. Deeming; Robert E. Burgan; Jack D. Cohen

    1984-01-01

    The National Fire-Danger Rating System (NFDRS), implemented in 1972, has been revised and reissued as the 1978 NFDRS. This report describes the full developmental history of the NFDRS, including purpose, technical foundation, and structure. Includes an extensive bibliography and appendixes.

  12. Synchronization of motor unit firings: an epiphenomenon of firing rate characteristics not common inputs.

    Science.gov (United States)

    Kline, Joshua C; De Luca, Carlo J

    2016-01-01

    Synchronous motor unit firing instances have been attributed to anatomical inputs shared by motoneurons. Yet, there is a lack of empirical evidence confirming the notion that common inputs elicit synchronization under voluntary conditions. We tested this notion by measuring synchronization between motor unit action potential trains (MUAPTs) as their firing rates progressed within a contraction from a relatively low force level to a higher one. On average, the degree of synchronization decreased as the force increased. The common input notion provides no empirically supported explanation for the observed synchronization behavior. Therefore, we investigated a more probable explanation for synchronization. Our data set of 17,546 paired MUAPTs revealed that the degree of synchronization varies as a function of two characteristics of the motor unit firing rate: the similarity and the slope as a function of force. Both are measures of the excitation of the motoneurons. As the force generated by the muscle increases, the firing rate slope decreases, and the synchronization correspondingly decreases. Different muscles have motor units with different firing rate characteristics and display different amounts of synchronization. Although this association is not proof of causality, it consistently explains our observations and strongly suggests further investigation. So viewed, synchronization is likely an epiphenomenon, subject to countless unknown neural interactions. As such, synchronous firing instances may not be the product of a specific design and may not serve a specific physiological purpose. Our explanation for synchronization has the advantage of being supported by empirical evidence, whereas the common input does not. Copyright © 2016 the American Physiological Society.

  13. Spontaneous Emission and Energy Transfer Rates Near a Coated Metallic Cylinder

    OpenAIRE

    BRADLEY, LOUISE

    2014-01-01

    PUBLISHED The spontaneous emission and energy transfer rates of quantum systems in proximity to a dielectrically coated metallic cylinder are investigated using a Green's tensor formalism. The excitation of surface plasmon modes can significantly modify these rates. The spontaneous emission and energy transfer rates are investigated as a function of the material and dimensions of the core and coating, as well as the emission wavelength of the donor. For the material of the core we consider...

  14. Fire precautions at petroleum refineries and bulk storage installations

    Energy Technology Data Exchange (ETDEWEB)

    1993-10-01

    Topics covered in this Code of Practice include petroleum products and combustion, site evaluation for fire defence, and fire prevention, protection, detection, systems, fighting, and fire fighting facilities in storage areas. Appendices cover legal requirements and enforcement arrangements, application rates for fire water and foam, codes of practice, flammable limits of petroleum compounds, flash points and spontaneous ignition temperatures and classification of fires. (UK)

  15. Spontaneous mutation rate in Chinese hamster cell clones differing in UV-sensitivity

    International Nuclear Information System (INIS)

    Manuilova, E.S.; Bagrova, A.M.; Moskovskij Gosudarstvennyj Univ.

    1983-01-01

    The spontaneous rate of appearance of mutations to 6-mercaptopurine (6 MP) resistence in the cells of CHR2 and CHs2 clones dofferent in sensitivity to lethal and matagenous effect of UV-rays, is investigated. Increased UV-sensitivity of CHs2 clone is caused by the violation of postreplicative DNA reparation. It is established that the purity of spontaneously occuring mutations in both clones turns out to be similar, i.e. (1.5-1.8)x10 -5 for the cell pergeneration. It is shown that the effect of postreplicative DNA reparation in the cells of chinese hamster is not connected with the increase of spontaneous mutation ability. The problem on the possible role of reparation in the mechanism of appearance of spontaneous and induced mutations in the cells of Chinese hamster with increased UV-sensitivity is discussed

  16. Assessment of baroreflex sensitivity from spontaneous oscillations of blood pressure and heart rate: proven clinical value?

    International Nuclear Information System (INIS)

    Pinna, Gian Domenico; Maestri, Roberto; La Rovere, Maria Teresa

    2015-01-01

    The baroreceptor-heart rate reflex (baroreflex sensitivity, BRS) is a key mechanism contributing to the neural regulation of the cardiovascular system. Several methods have been proposed so far to assess BRS by analyzing the spontaneous beat-to-beat fluctuations of arterial blood pressure and heart rate. These methods are inherently simple, non-invasive and low-cost. This study is an attempt to address the question of whether spontaneous baroreflex methods have proven to be of value in the clinical setting. In the first part of this article, we critically review most representative clinical studies using spontaneous BRS techniques either for risk stratification or treatment evaluation, these being major issues in the clinical management of the patients. In the second part, we address two important aspects of spontaneous BRS measurements: measurability and reliability. Estimation of BRS in the studies selected for the review was performed according to the sequence, transfer function, alpha-index and phase-rectified signal averaging method. Arterial blood pressure was recorded non-invasively during supine, short-term (<30 min) laboratory recordings. The conclusion from this review is that spontaneous BRS techniques have been shown to be of great value in clinical practice but further work is needed to confirm the validity of previous findings and to widen the field of clinical applications. Measurability and reliability can be a major issue in the measurement of spontaneous BRS, particularly in some patient populations like post-myocardial infarction and heart failure patents. Main causes of poor measurability are: non-sinus rhythm, a high rate of ectopic beats and the need for recorded time series of RR interval and arterial blood pressure to satisfy the constraints of the different BRS estimation algorithms. As for reliability, within-subject variability is rather high in the measurements of spontaneous BRS and, therefore, should be carefully taken into account

  17. The relationship of motor unit size, firing rate and force.

    Science.gov (United States)

    Conwit, R A; Stashuk, D; Tracy, B; McHugh, M; Brown, W F; Metter, E J

    1999-07-01

    Using a clinical electromyographic (EMG) protocol, motor units were sampled from the quadriceps femoris during isometric contractions at fixed force levels to examine how average motor unit size and firing rate relate to force generation. Mean firing rates (mFRs) and sizes (mean surface-detected motor unit action potential (mS-MUAP) area) of samples of active motor units were assessed at various force levels in 79 subjects. MS-MUAP size increased linearly with increased force generation, while mFR remained relatively constant up to 30% of a maximal force and increased appreciably only at higher force levels. A relationship was found between muscle force and mS-MUAP area (r2 = 0.67), mFR (r2 = 0.38), and the product of mS-MUAP area and mFR (mS-MUAP x mFR) (r2 = 0.70). The results support the hypothesis that motor units are recruited in an orderly manner during forceful contractions, and that in large muscles only at higher levels of contraction ( > 30% MVC) do mFRs increase appreciably. MS-MUAP and mFR can be assessed using clinical EMG techniques and they may provide a physiological basis for analyzing the role of motor units during muscle force generation.

  18. Maximum heart rate in brown trout (Salmo trutta fario) is not limited by firing rate of pacemaker cells.

    Science.gov (United States)

    Haverinen, Jaakko; Abramochkin, Denis V; Kamkin, Andre; Vornanen, Matti

    2017-02-01

    Temperature-induced changes in cardiac output (Q̇) in fish are largely dependent on thermal modulation of heart rate (f H ), and at high temperatures Q̇ collapses due to heat-dependent depression of f H This study tests the hypothesis that firing rate of sinoatrial pacemaker cells sets the upper thermal limit of f H in vivo. To this end, temperature dependence of action potential (AP) frequency of enzymatically isolated pacemaker cells (pacemaker rate, f PM ), spontaneous beating rate of isolated sinoatrial preparations (f SA ), and in vivo f H of the cold-acclimated (4°C) brown trout (Salmo trutta fario) were compared under acute thermal challenges. With rising temperature, f PM steadily increased because of the acceleration of diastolic depolarization and shortening of AP duration up to the break point temperature (T BP ) of 24.0 ± 0.37°C, at which point the electrical activity abruptly ceased. The maximum f PM at T BP was much higher [193 ± 21.0 beats per minute (bpm)] than the peak f SA (94.3 ± 6.0 bpm at 24.1°C) or peak f H (76.7 ± 2.4 at 15.7 ± 0.82°C) (P brown trout in vivo. Copyright © 2017 the American Physiological Society.

  19. Cavity-enhanced spontaneous emission rates for rhodamine 6-G in levitated microdroplets

    International Nuclear Information System (INIS)

    Barnes, M.D.; Whitten, W.B.; Ramsey, J.M.; Arnold, S.

    1992-01-01

    Fluorescence decay kinetics of Rhodamine 6-G molecules in levitated glycerol microdroplets (4--20 microns in diameter) have been investigated to determine the effects of spherical cavity resonances on spontaneous emission rates. For droplet diameters greater than 10 microns, the fluorescence lifetime is essentially the same as in bulk glycerol. As the droplet diameter is decreased below 10 microns, bi-exponential decay behavior is observed with a slow component whose rate is similar to bulk glycerol, and a fast component whose rate is as much as a factor of 10 larger than the bulk decay rate. This fast component is attributed to cavity enhancement of the spontaneous emission rate and, within the weak coupling approximation, a value for the homogeneous linewidth at room temperature can be estimated from the fluorescence lifetime data

  20. Estimates of the rate and distribution of fitness effects of spontaneous mutation in Saccharomyces cerevisiae

    NARCIS (Netherlands)

    Zeyl, C.; Visser, de J.A.G.M.

    2001-01-01

    The per-genome, per-generation rate of spontaneous mutation affecting fitness (U) and the mean fitness cost per mutation (s) are important parameters in evolutionary genetics, but have been estimated for few species. We estimated U and sh (the heterozygous effect of mutations) for two diploid yeast

  1. Transfer of spontaneously hatching or hatched blastocyst yields better pregnancy rates than expanded blastocyst transfer

    Directory of Open Access Journals (Sweden)

    Natachandra M Chimote

    2013-01-01

    Full Text Available Context: Blastocyst stage embryo transfer (ET has become routine practice in recent years. However, probably due to limitations of assisted hatching techniques, expanded blastocyst transfer (EBT is still the preferred mode. Inexplicably, not much consideration has been given to spontaneously hatching/hatched blastocyst transfer (SHBT. Aim: This study aimed to investigate developmental potential of spontaneously hatching/hatched blastocyst against EBT in in vitro fertilization (IVF cycles. Settings and Design: Prospective study of 146 women undergoing their first IVF- ET cycle. SUBJECTS AND Methods: On the basis of blastocyst status, women were classified into SHBT and EBT groups. Intracytoplasmic sperm injection cycles were excluded to remove male factor bias. Implantation rate (IR, clinical pregnancy rate, and live birth rate were the main outcome measures. Statistical Analysis: Graph-pad Prism 5 statistical package. Results: SHBT group showed significantly higher blastocyst formation rate (53.3 ± 17.5 vs. 43.1 ± 14.5%, P = 0.0098, top-quality blastocysts (71.8 vs. 53.7%, P = 0.0436, IR (43.6 vs. 27.9%, P = 0.0408, pregnancy rate (59.4 vs. 45.1%, P = 0.0173, and live birth rate (36.8 vs. 22.8%, P = 0.003 compared to EBT group. Multiple pregnancy rates remained comparable between the two groups. Implantation correlated strongly with top-quality blastocysts (Pearson, r = 0.4441 in SHBT group, while the correlation was nonsignificant in EBT group. Conclusion: Extending culture of expanded blastocysts by a few hours to allow transfer of spontaneously hatching/hatched blastocysts gives higher implantation and pregnancy rates with no added risk of multiple gestations. Spontaneously hatching/hatched blastocysts have a better potential to implant and develop into a positive pregnancy.

  2. A complex-valued firing-rate model that approximates the dynamics of spiking networks.

    Directory of Open Access Journals (Sweden)

    Evan S Schaffer

    2013-10-01

    Full Text Available Firing-rate models provide an attractive approach for studying large neural networks because they can be simulated rapidly and are amenable to mathematical analysis. Traditional firing-rate models assume a simple form in which the dynamics are governed by a single time constant. These models fail to replicate certain dynamic features of populations of spiking neurons, especially those involving synchronization. We present a complex-valued firing-rate model derived from an eigenfunction expansion of the Fokker-Planck equation and apply it to the linear, quadratic and exponential integrate-and-fire models. Despite being almost as simple as a traditional firing-rate description, this model can reproduce firing-rate dynamics due to partial synchronization of the action potentials in a spiking model, and it successfully predicts the transition to spike synchronization in networks of coupled excitatory and inhibitory neurons.

  3. A complex-valued firing-rate model that approximates the dynamics of spiking networks.

    Science.gov (United States)

    Schaffer, Evan S; Ostojic, Srdjan; Abbott, L F

    2013-10-01

    Firing-rate models provide an attractive approach for studying large neural networks because they can be simulated rapidly and are amenable to mathematical analysis. Traditional firing-rate models assume a simple form in which the dynamics are governed by a single time constant. These models fail to replicate certain dynamic features of populations of spiking neurons, especially those involving synchronization. We present a complex-valued firing-rate model derived from an eigenfunction expansion of the Fokker-Planck equation and apply it to the linear, quadratic and exponential integrate-and-fire models. Despite being almost as simple as a traditional firing-rate description, this model can reproduce firing-rate dynamics due to partial synchronization of the action potentials in a spiking model, and it successfully predicts the transition to spike synchronization in networks of coupled excitatory and inhibitory neurons.

  4. Fire danger rating over Mediterranean Europe based on fire radiative power derived from Meteosat

    Science.gov (United States)

    Pinto, Miguel M.; DaCamara, Carlos C.; Trigo, Isabel F.; Trigo, Ricardo M.; Feridun Turkman, K.

    2018-02-01

    We present a procedure that allows the operational generation of daily forecasts of fire danger over Mediterranean Europe. The procedure combines historical information about radiative energy released by fire events with daily meteorological forecasts, as provided by the Satellite Application Facility for Land Surface Analysis (LSA SAF) and the European Centre for Medium-Range Weather Forecasts (ECMWF). Fire danger is estimated based on daily probabilities of exceedance of daily energy released by fires occurring at the pixel level. Daily probability considers meteorological factors by means of the Canadian Fire Weather Index (FWI) and is estimated using a daily model based on a generalized Pareto distribution. Five classes of fire danger are then associated with daily probability estimated by the daily model. The model is calibrated using 13 years of data (2004-2016) and validated against the period of January-September 2017. Results obtained show that about 72 % of events releasing daily energy above 10 000 GJ belong to the extreme class of fire danger, a considerably high fraction that is more than 1.5 times the values obtained when using the currently operational Fire Danger Forecast module of the European Forest Fire Information System (EFFIS) or the Fire Risk Map (FRM) product disseminated by the LSA SAF. Besides assisting in wildfire management, the procedure is expected to help in decision making on prescribed burning within the framework of agricultural and forest management practices.

  5. Fire danger rating over Mediterranean Europe based on fire radiative power derived from Meteosat

    Directory of Open Access Journals (Sweden)

    M. M. Pinto

    2018-02-01

    Full Text Available We present a procedure that allows the operational generation of daily forecasts of fire danger over Mediterranean Europe. The procedure combines historical information about radiative energy released by fire events with daily meteorological forecasts, as provided by the Satellite Application Facility for Land Surface Analysis (LSA SAF and the European Centre for Medium-Range Weather Forecasts (ECMWF. Fire danger is estimated based on daily probabilities of exceedance of daily energy released by fires occurring at the pixel level. Daily probability considers meteorological factors by means of the Canadian Fire Weather Index (FWI and is estimated using a daily model based on a generalized Pareto distribution. Five classes of fire danger are then associated with daily probability estimated by the daily model. The model is calibrated using 13 years of data (2004–2016 and validated against the period of January–September 2017. Results obtained show that about 72 % of events releasing daily energy above 10 000 GJ belong to the extreme class of fire danger, a considerably high fraction that is more than 1.5 times the values obtained when using the currently operational Fire Danger Forecast module of the European Forest Fire Information System (EFFIS or the Fire Risk Map (FRM product disseminated by the LSA SAF. Besides assisting in wildfire management, the procedure is expected to help in decision making on prescribed burning within the framework of agricultural and forest management practices.

  6. Variable synaptic strengths controls the firing rate distribution in feedforward neural networks.

    Science.gov (United States)

    Ly, Cheng; Marsat, Gary

    2018-02-01

    Heterogeneity of firing rate statistics is known to have severe consequences on neural coding. Recent experimental recordings in weakly electric fish indicate that the distribution-width of superficial pyramidal cell firing rates (trial- and time-averaged) in the electrosensory lateral line lobe (ELL) depends on the stimulus, and also that network inputs can mediate changes in the firing rate distribution across the population. We previously developed theoretical methods to understand how two attributes (synaptic and intrinsic heterogeneity) interact and alter the firing rate distribution in a population of integrate-and-fire neurons with random recurrent coupling. Inspired by our experimental data, we extend these theoretical results to a delayed feedforward spiking network that qualitatively capture the changes of firing rate heterogeneity observed in in-vivo recordings. We demonstrate how heterogeneous neural attributes alter firing rate heterogeneity, accounting for the effect with various sensory stimuli. The model predicts how the strength of the effective network connectivity is related to intrinsic heterogeneity in such delayed feedforward networks: the strength of the feedforward input is positively correlated with excitability (threshold value for spiking) when firing rate heterogeneity is low and is negatively correlated with excitability with high firing rate heterogeneity. We also show how our theory can be used to predict effective neural architecture. We demonstrate that neural attributes do not interact in a simple manner but rather in a complex stimulus-dependent fashion to control neural heterogeneity and discuss how it can ultimately shape population codes.

  7. Stable Control of Firing Rate Mean and Variance by Dual Homeostatic Mechanisms.

    Science.gov (United States)

    Cannon, Jonathan; Miller, Paul

    2017-12-01

    Homeostatic processes that provide negative feedback to regulate neuronal firing rates are essential for normal brain function. Indeed, multiple parameters of individual neurons, including the scale of afferent synapse strengths and the densities of specific ion channels, have been observed to change on homeostatic time scales to oppose the effects of chronic changes in synaptic input. This raises the question of whether these processes are controlled by a single slow feedback variable or multiple slow variables. A single homeostatic process providing negative feedback to a neuron's firing rate naturally maintains a stable homeostatic equilibrium with a characteristic mean firing rate; but the conditions under which multiple slow feedbacks produce a stable homeostatic equilibrium have not yet been explored. Here we study a highly general model of homeostatic firing rate control in which two slow variables provide negative feedback to drive a firing rate toward two different target rates. Using dynamical systems techniques, we show that such a control system can be used to stably maintain a neuron's characteristic firing rate mean and variance in the face of perturbations, and we derive conditions under which this happens. We also derive expressions that clarify the relationship between the homeostatic firing rate targets and the resulting stable firing rate mean and variance. We provide specific examples of neuronal systems that can be effectively regulated by dual homeostasis. One of these examples is a recurrent excitatory network, which a dual feedback system can robustly tune to serve as an integrator.

  8. A memristive spiking neuron with firing rate coding

    Directory of Open Access Journals (Sweden)

    Marina eIgnatov

    2015-10-01

    Full Text Available Perception, decisions, and sensations are all encoded into trains of action potentials in the brain. The relation between stimulus strength and all-or-nothing spiking of neurons is widely believed to be the basis of this coding. This initiated the development of spiking neuron models; one of today's most powerful conceptual tool for the analysis and emulation of neural dynamics. The success of electronic circuit models and their physical realization within silicon field-effect transistor circuits lead to elegant technical approaches. Recently, the spectrum of electronic devices for neural computing has been extended by memristive devices, mainly used to emulate static synaptic functionality. Their capabilities for emulations of neural activity were recently demonstrated using a memristive neuristor circuit, while a memristive neuron circuit has so far been elusive. Here, a spiking neuron model is experimentally realized in a compact circuit comprising memristive and memcapacitive devices based on the strongly correlated electron material vanadium dioxide (VO2 and on the chemical electromigration cell Ag/TiO2-x/Al. The circuit can emulate dynamical spiking patterns in response to an external stimulus including adaptation, which is at the heart of firing rate coding as first observed by E.D. Adrian in 1926.

  9. A Scale for Rating Fire-Prevention Contactors

    Science.gov (United States)

    M.L. Doolittle

    1979-01-01

    A scale is constructed to help fire-prevention program administrators determine if an individual contactor is effective at influencing people. The 24 items in the scale indicate the qualities that an effective contactor should have.

  10. High glucose increases action potential firing of catecholamine neurons in the nucleus of the solitary tract by increasing spontaneous glutamate inputs.

    Science.gov (United States)

    Roberts, Brandon L; Zhu, Mingyan; Zhao, Huan; Dillon, Crystal; Appleyard, Suzanne M

    2017-09-01

    Glucose is a crucial substrate essential for cell survival and function. Changes in glucose levels impact neuronal activity and glucose deprivation increases feeding. Several brain regions have been shown to respond to glucoprivation, including the nucleus of the solitary tract (NTS) in the brain stem. The NTS is the primary site in the brain that receives visceral afferent information from the gastrointestinal tract. The catecholaminergic (CA) subpopulation within the NTS modulates many homeostatic functions including cardiovascular reflexes, respiration, food intake, arousal, and stress. However, it is not known if they respond to changes in glucose. Here we determined whether NTS-CA neurons respond to changes in glucose concentration and the mechanism involved. We found that decreasing glucose concentrations from 5 mM to 2 mM to 1 mM, significantly decreased action potential firing in a cell-attached preparation, whereas increasing it back to 5 mM increased the firing rate. This effect was dependent on glutamate release from afferent terminals and required presynaptic 5-HT 3 Rs. Decreasing the glucose concentration also decreased both basal and 5-HT 3 R agonist-induced increase in the frequency of spontaneous glutamate inputs onto NTS-CA neurons. Low glucose also blunted 5-HT-induced inward currents in nodose ganglia neurons, which are the cell bodies of vagal afferents. The effect of low glucose in both nodose ganglia cells and in NTS slices was mimicked by the glucokinase inhibitor glucosamine. This study suggests that NTS-CA neurons are glucosensing through a presynaptic mechanism that is dependent on vagal glutamate release, 5-HT 3 R activity, and glucokinase. Copyright © 2017 the American Physiological Society.

  11. Importance of kynurenine 3-monooxygenase for spontaneous firing and pharmacological responses of midbrain dopamine neurons: Relevance for schizophrenia.

    Science.gov (United States)

    Tufvesson-Alm, Maximilian; Schwieler, Lilly; Schwarcz, Robert; Goiny, Michel; Erhardt, Sophie; Engberg, Göran

    2018-06-05

    Kynurenine 3-monooxygenase (KMO) is an essential enzyme of the kynurenine pathway, converting kynurenine into 3-hydroxykynurenine. Inhibition of KMO increases kynurenine, resulting in elevated levels of kynurenic acid (KYNA), an endogenous N-methyl-d-aspartate and α*7-nicotinic receptor antagonist. The concentration of KYNA is elevated in the brain of patients with schizophrenia, possibly as a result of a reduced KMO activity. In the present study, using in vivo single cell recording techniques, we investigated the electrophysiological characteristics of ventral tegmental area dopamine (VTA DA) neurons and their response to antipsychotic drugs in a KMO knock-out (K/O) mouse model. KMO K/O mice exhibited a marked increase in spontaneous VTA DA neuron activity as compared to wild-type (WT) mice. Furthermore, VTA DA neurons showed clear-cut, yet qualitatively opposite, responses to the antipsychotic drugs haloperidol and clozapine in the two genotypes. The anti-inflammatory drug parecoxib successfully lowered the firing activity of VTA DA neurons in KMO K/O, but not in WT mice. Minocycline, an antibiotic and anti-inflammatory drug, produced no effect in this regard. Taken together, the present data further support the usefulness of KMO K/O mice for studying distinct aspects of the pathophysiology and pharmacological treatment of psychiatric disorders such as schizophrenia. Copyright © 2018. Published by Elsevier Ltd.

  12. FIRE

    International Nuclear Information System (INIS)

    Brtis, J.S.; Hausheer, T.G.

    1990-01-01

    FIRE, a microcomputer based program to assist engineers in reviewing and documenting the fire protection impact of design changes has been developed. Acting as an electronic consultant, FIRE is designed to work with an experienced nuclear system engineer, who may not have any detailed fire protection expertise. FIRE helps the engineer to decide if a modification might adversely affect the fire protection design of the station. Since its first development, FIRE has been customized to reflect the fire protection philosophy of the Commonwealth Edison Company. That program is in early production use. This paper discusses the FIRE program in light of its being a useful application of expert system technologies in the power industry

  13. Noise in attractor networks in the brain produced by graded firing rate representations

    OpenAIRE

    Webb, Tristan J.; Rolls, Edmund T; Deco, Gustavo; Feng, Jianfeng

    2011-01-01

    Representations in the cortex are often distributed with graded firing rates in the neuronal populations. The firing rate\\ud probability distribution of each neuron to a set of stimuli is often exponential or gamma. In processes in the brain, such as\\ud decision-making, that are influenced by the noise produced by the close to random spike timings of each neuron for a given\\ud mean rate, the noise with this graded type of representation may be larger than with the binary firing rate distribut...

  14. An operational system of fire danger rating over Mediterranean Europe

    Science.gov (United States)

    Pinto, Miguel M.; DaCamara, Carlos C.; Trigo, Isabel F.; Trigo, Ricardo M.

    2017-04-01

    A methodology is presented to assess fire danger based on the probability of exceedance of prescribed thresholds of daily released energy. The procedure is developed and tested over Mediterranean Europe, defined by latitude circles of 35 and 45°N and meridians of 10°W and 27.5°E, for the period 2010-2016. The procedure involves estimating the so-called static and daily probabilities of exceedance. For a given point, the static probability is estimated by the ratio of the number of daily fire occurrences releasing energy above a given threshold to the total number of occurrences inside a cell centred at the point. The daily probability of exceedance which takes into account meteorological factors by means of the Canadian Fire Weather Index (FWI) is in turn estimated based on a Generalized Pareto distribution with static probability and FWI as covariates of the scale parameter. The rationale of the procedure is that small fires, assessed by the static probability, have a weak dependence on weather, whereas the larger fires strongly depend on concurrent meteorological conditions. It is shown that observed frequencies of exceedance over the study area for the period 2010-2016 match with the estimated values of probability based on the developed models for static and daily probabilities of exceedance. Some (small) variability is however found between different years suggesting that refinements can be made in future works by using a larger sample to further increase the robustness of the method. The developed methodology presents the advantage of evaluating fire danger with the same criteria for all the study area, making it a good parameter to harmonize fire danger forecasts and forest management studies. Research was performed within the framework of EUMETSAT Satellite Application Facility for Land Surface Analysis (LSA SAF). Part of methods developed and results obtained are on the basis of the platform supported by The Navigator Company that is currently providing

  15. Regional scales of fire danger rating in the forest: improved technique

    Directory of Open Access Journals (Sweden)

    A. V. Volokitina

    2017-04-01

    Full Text Available Wildland fires distribute unevenly in time and over area under the influence of weather and other factors. It is unfeasible to air patrol the whole forest area daily during a fire season as well as to keep all fire suppression forces constantly alert. Daily work and preparedness of forest fire protection services is regulated by the level of fire danger according to weather conditions (Nesterov’s index. PV-1 index, fire hazard class (Melekhov’s scale, regional scales (earlier called local scales. Unfortunately, there is still no unified comparable technique of making regional scales. As a result, it is difficult to maneuver forest fire protection resources, since the techniques currently used are not approved and not tested for their performance. They give fire danger rating incomparable even for neighboring regions. The paper analyzes the state-of-the-art in Russia and abroad. It is stated the irony is that with factors of fire danger measured quantitatively, the fire danger itself as a function has no quantitative expression. Thus, selection of an absolute criteria is of high importance for improvement of daily fire danger rating. On the example of the Chunsky forest ranger station (Krasnoyarsk Krai, an improved technique is suggested of making comparable local scales of forest fire danger rating based on an absolute criterion of fire danger rating – a probable density of active fires per million ha. A method and an algorithm are described of automatized local scales of fire danger that should facilitate effective creation of similar scales for any forest ranger station or aviation regional office using a database on forest fires and weather conditions. The information system of distant monitoring by Federal Forestry Agency of Russia is analyzed for its application in making local scales. To supplement the existing weather station net it is suggested that automatic compact weather stations or, if the latter is not possible, simple

  16. Error associated with model predictions of wildland fire rate of spread

    Science.gov (United States)

    Miguel G. Cruz; Martin E. Alexander

    2015-01-01

    How well can we expect to predict the spread rate of wildfires and prescribed fires? The degree of accuracy in model predictions of wildland fire behaviour characteristics are dependent on the model's applicability to a given situation, the validity of the model's relationships, and the reliability of the model input data (Alexander and Cruz 2013b#. We...

  17. Firing patterns of spontaneously active motor units in spinal cord-injured subjects

    NARCIS (Netherlands)

    Zijdewind, Inge; Thomas, Christine K.

    Involuntary motor unit activity at low rates is common in hand muscles paralysed by spinal cord injury. Our aim was to describe these patterns of motor unit behaviour in relation to motoneurone and motor unit properties. Intramuscular electromyographic activity (EMG), surface EMG and force were

  18. A Constant Rate of Spontaneous Mutation in DNA-Based Microbes

    Science.gov (United States)

    Drake, John W.

    1991-08-01

    In terms of evolution and fitness, the most significant spontaneous mutation rate is likely to be that for the entire genome (or its nonfrivolous fraction). Information is now available to calculate this rate for several DNA-based haploid microbes, including bacteriophages with single- or double-stranded DNA, a bacterium, a yeast, and a filamentous fungus. Their genome sizes vary by ≈6500-fold. Their average mutation rates per base pair vary by ≈16,000-fold, whereas their mutation rates per genome vary by only ≈2.5-fold, apparently randomly, around a mean value of 0.0033 per DNA replication. The average mutation rate per base pair is inversely proportional to genome size. Therefore, a nearly invariant microbial mutation rate appears to have evolved. Because this rate is uniform in such diverse organisms, it is likely to be determined by deep general forces, perhaps by a balance between the usually deleterious effects of mutation and the physiological costs of further reducing mutation rates.

  19. On-chip plasmonic cavity-enhanced spontaneous emission rate at the zero-phonon line

    DEFF Research Database (Denmark)

    Siampour, Hamidreza; Kumar, Shailesh; Bozhevolnyi, Sergey I.

    Highly confined surface plasmon polariton (SPP) modes can be utilized to enhance light-matter interaction at the single emitter level of quantum optical systems [1-4]. Dielectric-loaded SPP waveguides (DLSPPWs) confine SPPs laterally with relatively low propagation loss, enabling to benefit both ...... and an up to 42-fold spontaneous emission rate enhancement at the zero-phonon line (a ∼7-fold resonance enhancement in addition to a ∼6-fold broadband enhancement) is achieved, revealing the potential of our approach for on-chip realization of quantum-optical networks....... from a large Purcell factor and from a large radiative efficiency (low quenching rates) [1, 2]. In this work, we present a DLSPPW-based Bragg cavity resonator to direct emission from a single diamond nitrogen vacancy (NV) center into the zero-phonon line (Fig. 1). A quality factor of ∼70 for the cavity...

  20. Hybridization alters spontaneous mutation rates in a parent-of-origin-dependent fashion in Arabidopsis.

    Science.gov (United States)

    Bashir, Tufail; Sailer, Christian; Gerber, Florian; Loganathan, Nitin; Bhoopalan, Hemadev; Eichenberger, Christof; Grossniklaus, Ueli; Baskar, Ramamurthy

    2014-05-01

    Over 70 years ago, increased spontaneous mutation rates were observed in Drosophila spp. hybrids, but the genetic basis of this phenomenon is not well understood. The model plant Arabidopsis (Arabidopsis thaliana) offers unique opportunities to study the types of mutations induced upon hybridization and the frequency of their occurrence. Understanding the mutational effects of hybridization is important, as many crop plants are grown as hybrids. Besides, hybridization is important for speciation and its effects on genome integrity could be critical, as chromosomal rearrangements can lead to reproductive isolation. We examined the rates of hybridization-induced point and frameshift mutations as well as homologous recombination events in intraspecific Arabidopsis hybrids using a set of transgenic mutation detector lines that carry mutated or truncated versions of a reporter gene. We found that hybridization alters the frequency of different kinds of mutations. In general, Columbia (Col)×Cape Verde Islands and Col×C24 hybrid progeny had decreased T→G and T→A transversion rates but an increased C→T transition rate. Significant changes in frameshift mutation rates were also observed in some hybrids. In Col×C24 hybrids, there is a trend for increased homologous recombination rates, except for the hybrids from one line, while in Col×Cape Verde Islands hybrids, this rate is decreased. The overall genetic distance of the parents had no influence on mutation rates in the progeny, as closely related accessions on occasion displayed higher mutation rates than accessions that are separated farther apart. However, reciprocal hybrids had significantly different mutation rates, suggesting parent-of-origin-dependent effects on the mutation frequency.

  1. Endo- and exocytic rate constants for spontaneous and protein kinase C-activated T cell receptor cycling

    DEFF Research Database (Denmark)

    Menné, Charlotte; Møller Sørensen, Tine; Siersma, Volkert

    2002-01-01

    To determine the rate constants of spontaneous and activated TCR cycling, we examined TCR endo- and exocytosis in the human T cell line Jurkat by three different methods. Using a simple kinetic model for TCR cycling and non-linear regression analyses, we found that the spontaneous endocytic rate...... constant of the TCR was low (approximately 0.012 min(-1)) whereas the spontaneous exocytic rate constant was similar to that of other cycling receptors (approximately 0.055 min(-1)). Following protein kinase C activation (PKC) the endocytic rate constant was increased tenfold (to approximately 0.128 min(-1......)) whereas the exocytic rate constant was unaffected. Thus, the TCR becomes a rapidly cycling receptor with kinetics similar to classical cycling receptors subsequent to PKC activation. This results in a reduction of the half-life of cell surface expressed TCR from approximately 58 to 6 min and allows rapid...

  2. The rate and effects of spontaneous mutation on fitness traits in the social amoeba, Dictyostelium discoideum.

    Science.gov (United States)

    Hall, David W; Fox, Sara; Kuzdzal-Fick, Jennie J; Strassmann, Joan E; Queller, David C

    2013-07-08

    We performed a mutation accumulation (MA) experiment in the social amoeba Dictyostelium discoideum to estimate the rate and distribution of effects of spontaneous mutations affecting eight putative fitness traits. We found that the per-generation mutation rate for most fitness components is 0.0019 mutations per haploid genome per generation or larger. This rate is an order of magnitude higher than estimates for fitness components in the unicellular eukaryote Saccharomyces cerevisiae, even though the base-pair substitution rate is two orders of magnitude lower. The high rate of fitness-altering mutations observed in this species may be partially explained by a large mutational target relative to S. cerevisiae. Fitness-altering mutations also may occur primarily at simple sequence repeats, which are common throughout the genome, including in coding regions, and may represent a target that is particularly likely to give fitness effects upon mutation. The majority of mutations had deleterious effects on fitness, but there was evidence for a substantial fraction, up to 40%, being beneficial for some of the putative fitness traits. Competitive ability within the multicellular slug appears to be under weak directional selection, perhaps reflecting the fact that slugs are sometimes, but not often, comprised of multiple clones in nature. Evidence for pleiotropy among fitness components across MA lines was absent, suggesting that mutations tend to act on single fitness components.

  3. Motor unit firing rate patterns during voluntary muscle force generation: a simulation study

    Science.gov (United States)

    Hu, Xiaogang; Rymer, William Z.; Suresh, Nina L.

    2014-04-01

    Objective. Muscle force is generated by a combination of motor unit (MU) recruitment and changes in the discharge rate of active MUs. There have been two basic MU recruitment and firing rate paradigms reported in the literature, which describe the control of the MUs during force generation. The first (termed the reverse ‘onion skin’ profile), exhibits lower firing rates for lower threshold units, with higher firing rates occurring in higher threshold units. The second (termed the ‘onion skin’ profile), exhibits an inverse arrangement, with lower threshold units reaching higher firing rates. Approach. Using a simulation of the MU activity in a hand muscle, this study examined the force generation capacity and the variability of the muscle force magnitude at different excitation levels of the MU pool under these two different MU control paradigms. We sought to determine which rate/recruitment scheme was more efficient for force generation, and which scheme gave rise to the lowest force variability. Main results. We found that the force output of both firing patterns leads to graded force output at low excitation levels, and that the force generation capacity of the two different paradigms diverged around 50% excitation. In the reverse ‘onion skin’ pattern, at 100% excitation, the force output reached up to 88% of maximum force, whereas for the ‘onion skin’ pattern, the force output only reached up to 54% of maximum force at 100% excitation. The force variability was lower at the low to moderate force levels under the ‘onion skin’ paradigm than with the reverse ‘onion skin’ firing patterns, but this effect was reversed at high force levels. Significance. This study captures the influence of MU recruitment and firing rate organization on muscle force properties, and our results suggest that the different firing organizations can be beneficial at different levels of voluntary muscle force generation and perhaps for different tasks.

  4. Decreased spontaneous eye blink rates in chronic cannabis users: evidence for striatal cannabinoid-dopamine interactions.

    Directory of Open Access Journals (Sweden)

    Mikael A Kowal

    Full Text Available Chronic cannabis use has been shown to block long-term depression of GABA-glutamate synapses in the striatum, which is likely to reduce the extent to which endogenous cannabinoids modulate GABA- and glutamate-related neuronal activity. The current study aimed at investigating the effect of this process on striatal dopamine levels by studying the spontaneous eye blink rate (EBR, a clinical marker of dopamine level in the striatum. 25 adult regular cannabis users and 25 non-user controls matched for age, gender, race, and IQ were compared. Results show a significant reduction in EBR in chronic users as compared to non-users, suggesting an indirect detrimental effect of chronic cannabis use on striatal dopaminergic functioning. Additionally, EBR correlated negatively with years of cannabis exposure, monthly peak cannabis consumption, and lifetime cannabis consumption, pointing to a relationship between the degree of impairment of striatal dopaminergic transmission and cannabis consumption history.

  5. Firing rate dynamics in recurrent spiking neural networks with intrinsic and network heterogeneity.

    Science.gov (United States)

    Ly, Cheng

    2015-12-01

    Heterogeneity of neural attributes has recently gained a lot of attention and is increasing recognized as a crucial feature in neural processing. Despite its importance, this physiological feature has traditionally been neglected in theoretical studies of cortical neural networks. Thus, there is still a lot unknown about the consequences of cellular and circuit heterogeneity in spiking neural networks. In particular, combining network or synaptic heterogeneity and intrinsic heterogeneity has yet to be considered systematically despite the fact that both are known to exist and likely have significant roles in neural network dynamics. In a canonical recurrent spiking neural network model, we study how these two forms of heterogeneity lead to different distributions of excitatory firing rates. To analytically characterize how these types of heterogeneities affect the network, we employ a dimension reduction method that relies on a combination of Monte Carlo simulations and probability density function equations. We find that the relationship between intrinsic and network heterogeneity has a strong effect on the overall level of heterogeneity of the firing rates. Specifically, this relationship can lead to amplification or attenuation of firing rate heterogeneity, and these effects depend on whether the recurrent network is firing asynchronously or rhythmically firing. These observations are captured with the aforementioned reduction method, and furthermore simpler analytic descriptions based on this dimension reduction method are developed. The final analytic descriptions provide compact and descriptive formulas for how the relationship between intrinsic and network heterogeneity determines the firing rate heterogeneity dynamics in various settings.

  6. Increasing inhibitory input increases neuronal firing rate: why and when? Diffusion process cases

    Energy Technology Data Exchange (ETDEWEB)

    Feng Jianfeng [COGS, Sussex University (United Kingdom)]. E-mail: jf218@cam.ac.uk; Wei Gang [Department of Mathematics, Hong Kong Baptist University, Hong Kong (China)]. E-mail gwei@math.hkbu.edu.hk

    2001-09-21

    Increasing inhibitory input to single neuronal models, such as the FitzHugh-Nagumo model and the Hodgkin-Huxley model, can sometimes increase their firing rates, a phenomenon which we term inhibition-boosted firing (IBF). Here we consider neuronal models with diffusion approximation inputs, i.e. they share the identical first- and second-order statistics of the corresponding Poisson process inputs. Using the integrate-and-fire model and the IF-FHN model, we explore theoretically how and when IBF can happen. For both models, it is shown that there is a critical input frequency at which the efferent firing rate is identical when the neuron receives purely excitatory inputs or exactly balanced inhibitory and excitatory inputs. When the input frequency is lower than the critical frequency, IBF occurs. (author)

  7. Numerical Studies on Heat Release Rate in Room Fire on Liquid Fuel under Different Ventilation Factors

    Directory of Open Access Journals (Sweden)

    N. Cai

    2012-01-01

    Full Text Available Heat release rate (HRR of the design fire is the most important parameter in assessing building fire hazards. However, HRR in room fire was only studied by computational fluid dynamics (CFD in most of the projects determining fire safety provisions by performance-based design. In contrast to ten years ago, officers in the Far East are now having better knowledge of CFD. Two common questions are raised on CFD-predicted results on describing free boundaries; and on computing grid size. In this work, predicting HRR by the CFD model was justified with experimental room pool fire data reported earlier. The software fire dynamics simulator (FDS version 5 was selected as the CFD simulation tool. Prescribed input heating rate based on the experimental results was used with the liquid fuel model in FDS. Five different free boundary conditions were investigated to predict HRR. Grid sensitivity study was carried out using one stretched mesh and multiple uniform meshes with different grid sizes. As it is difficult to have the entire set of CFD predicted results agreed with experiments, macroscopic flow parameters on the mass flow rate through door opening predicted by CFD were also justified by another four conditions with different ventilation factors.

  8. Influence of heating rate and temperature firing on the properties of bodies of red ceramic

    International Nuclear Information System (INIS)

    Silva, B.J. da; Goncalves, W.P.; Cartaxo, J.M.; Macedo, R.S.; Neves, G.A.; Santana, L.N.L.; Menezes, R.R.

    2011-01-01

    In the red ceramic industry, the firing is one of the main stages of the production process. There are two heating rates prevailing at this stage: the slow (traditional ceramics) and fast. The slow rate more used in Brazil, is considered delayed. This study aims to evaluate the influence of particle size and chemical composition of three mixture of clay, used in the manufacture of red ceramic products and to study the influence of the firing temperature on their technological properties. When subjected to heating rates slow and fast. Initially, the mixtures were characterized subsequently were extruded, dried and subjected to firing at temperatures of 900 and 1000 ° C with heating rates of 5, 20 and 30 °C/min. The results indicated that the chemical composition and particle size influenced significantly the technological properties and that the bodies obtained with the paste that had lower levels of flux showed better stability. (author)

  9. Calcitonin gene-related peptide alters the firing rates of hypothalamic temperature sensitive and insensitive neurons

    Directory of Open Access Journals (Sweden)

    Grimm Eleanor R

    2008-07-01

    Full Text Available Abstract Background Transient hyperthermic shifts in body temperature have been linked to the endogenous hormone calcitonin gene-related peptide (CGRP, which can increase sympathetic activation and metabolic heat production. Recent studies have demonstrated that these centrally mediated responses may result from CGRP dependent changes in the activity of thermoregulatory neurons in the preoptic and anterior regions of the hypothalamus (POAH. Results Using a tissue slice preparation, we recorded the single-unit activity of POAH neurons from the adult male rat, in response to temperature and CGRP (10 μM. Based on the slope of firing rate as a function of temperature, neurons were classified as either warm sensitive or temperature insensitive. All warm sensitive neurons responded to CGRP with a significant decrease in firing rate. While CGRP did not alter the firing rates of some temperature insensitive neurons, responsive neurons showed an increase in firing rate. Conclusion With respect to current models of thermoregulatory control, these CGRP dependent changes in firing rate would result in hyperthermia. This suggests that both warm sensitive and temperature insensitive neurons in the POAH may play a role in producing this hyperthermic shift in temperature.

  10. Literature study regarding fire protection in nuclear power plants. Part I: Fire rated separations; Litteraturstudie angaaende brandskydd i kaernkraftverk. Del I: Brandteknisk separation

    Energy Technology Data Exchange (ETDEWEB)

    Isaksson, S [Swedish Testing and Research Inst., Boraas (Sweden)

    1995-06-01

    This literature study has been made on behalf of the Swedish Nuclear Power Inspectorate. The aim is to describe different aspects of fire protection in nuclear power plants. Conventional building codes can not give guidance on where to make fire rated separations in order to separate redundant trains of safety systems. The separation must originate in functional demands from the authorities on what functions are essential during and after a fire, and under what circumstances these functions shall be retained, i.e. the number of independent faults and initiating events. As a basic demand it is suggested to rate the strength of separations according to conventional building code, based on fire load. The whole separating construction shall have the same fire rating, including the ventilation system. Deviations from the basic demand can de done in case it can be proven that it is possible to compensate some or all of the fire rating with other measures. There is a general lack of statistical information regarding the reliability of fire separating constructions such as walls, fire doors, penetration seals and fire dampers. The amount of cables penetrating a seal is in many cases much higher in real installations than what has been tested for type approval. It would therefore be valuable to perform a furnace test with a more representative amount of cables passing through a penetration seal. Tests have shown that the 20 foot horizontal separation distance stipulated by NRC is not a guarantee against fire damage. Spatial separations based on general requirements shall not be allowed, but considered from case to case based on actual circumstances. For fire protection by isolation or coatings, it is of great importance to choose the method of protection carefully, to be compatible with the material it shall be applied on, and the environment and types of fire that may occur. 48 refs, 2 figs, 5 tabs.

  11. Burning Rate Emulator Experiments for Spacecraft Fire Safety

    Data.gov (United States)

    National Aeronautics and Space Administration — Experimental Investigation of Emulated Burning Rate at Various Gravity Levels Support for the initial development stages of a novel experimental apparatus, the...

  12. Dissociable effects of dopamine on neuronal firing rate and synchrony in the dorsal striatum

    Directory of Open Access Journals (Sweden)

    John M Burkhardt

    2009-10-01

    Full Text Available Previous studies showed that dopamine depletion leads to both changes in firing rate and in neuronal synchrony in the basal ganglia. Since dopamine D1 and D2 receptors are preferentially expressed in striatonigral and striatopallidal medium spiny neurons, respectively, we investigated the relative contribution of lack of D1 and/or D2-type receptor activation to the changes in striatal firing rate and synchrony observed after dopamine depletion. Similar to what was observed after dopamine depletion, co-administration of D1 and D2 antagonists to mice chronically implanted with multielectrode arrays in the striatum caused significant changes in firing rate, power of the local field potential (LFP oscillations, and synchrony measured by the entrainment of neurons to striatal local field potentials. However, although blockade of either D1 or D2 type receptors produced similarly severe akinesia, the effects on neural activity differed. Blockade of D2 receptors affected the firing rate of medium spiny neurons and the power of the LFP oscillations substantially, but it did not affect synchrony to the same extent. In contrast, D1 blockade affected synchrony dramatically, but had less substantial effects on firing rate and LFP power. Furthermore, there was no consistent relation between neurons changing firing rate and changing LFP entrainment after dopamine blockade. Our results suggest that the changes in rate and entrainment to the LFP observed in medium spiny neurons after dopamine depletion are somewhat dissociable, and that lack of D1- or D2-type receptor activation can exert independent yet interactive pathological effects during the progression of Parkinson’s disease.

  13. Influence of proprioceptive feedback on the firing rate and recruitment of motoneurons

    Science.gov (United States)

    De Luca, C. J.; Kline, J. C.

    2012-02-01

    We investigated the relationships of the firing rate and maximal recruitment threshold of motoneurons recorded during isometric contraction with the number of spindles in individual muscles. At force levels above 10% of maximal voluntary contraction, the firing rate was inversely related to the number of spindles in a muscle, with the slope of the relationship increasing with force. The maximal recruitment threshold of motor units increased linearly with the number of spindles in the muscle. Thus, muscles with a greater number of spindles had lower firing rates and a greater maximal recruitment threshold. These findings may be explained by a mechanical interaction between muscle fibres and adjacent spindles. During low-level (0% to 10%) voluntary contractions, muscle fibres of recruited motor units produce force twitches that activate nearby spindles to respond with an immediate excitatory feedback that reaches maximal level. As the force increases further, the twitches overlap and tend towards tetanization, the muscle fibres shorten, the spindles slacken, their excitatory firings decrease, and the net excitation to the homonymous motoneurons decreases. Motoneurons of muscles with greater number of spindles receive a greater decrease in excitation which reduces their firing rates, increases their maximal recruitment threshold, and changes the motoneuron recruitment distribution.

  14. Effects of fatigue on motor unit firing rate versus recruitment threshold relationships.

    Science.gov (United States)

    Stock, Matt S; Beck, Travis W; Defreitas, Jason M

    2012-01-01

    The purpose of this study was to examine the influence of fatigue on the average firing rate versus recruitment threshold relationships for the vastus lateralis (VL) and vastus medialis. Nineteen subjects performed ten maximum voluntary contractions of the dominant leg extensors. Before and after this fatiguing protocol, the subjects performed a trapezoid isometric muscle action of the leg extensors, and bipolar surface electromyographic signals were detected from both muscles. These signals were then decomposed into individual motor unit action potential trains. For each subject and muscle, the relationship between average firing rate and recruitment threshold was examined using linear regression analyses. For the VL, the linear slope coefficients and y-intercepts for these relationships increased and decreased, respectively, after fatigue. For both muscles, many of the motor units decreased their firing rates. With fatigue, recruitment of higher threshold motor units resulted in an increase in slope for the VL. Copyright © 2011 Wiley Periodicals, Inc.

  15. Spontaneous eye blink rate as predictor of dopamine-related cognitive function-A review.

    Science.gov (United States)

    Jongkees, Bryant J; Colzato, Lorenza S

    2016-12-01

    An extensive body of research suggests the spontaneous eye blink rate (EBR) is a non-invasive indirect marker of central dopamine (DA) function, with higher EBR predicting higher DA function. In the present review we provide a comprehensive overview of this literature. We broadly divide the available research in studies that aim to disentangle the dopaminergic underpinnings of EBR, investigate its utility in diagnosis of DA-related disorders and responsivity to drug treatment, and, lastly, investigate EBR as predictor of individual differences in DA-related cognitive performance. We conclude (i) EBR can reflect both DA receptor subtype D1 and D2 activity, although baseline EBR might be most strongly related to the latter, (ii) EBR can predict hypo- and hyperdopaminergic activity as well as normalization of this activity following treatment, and (iii) EBR can reliably predict individual differences in performance on many cognitive tasks, in particular those related to reward-driven behavior and cognitive flexibility. In sum, this review establishes EBR as a useful predictor of DA in a wide variety of contexts. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Ia Afferent input alters the recruitment thresholds and firing rates of single human motor units.

    Science.gov (United States)

    Grande, G; Cafarelli, E

    2003-06-01

    Vibration of the patellar tendon recruits motor units in the knee extensors via excitation of muscle spindles and subsequent Ia afferent input to the alpha-motoneuron pool. Our first purpose was to determine if the recruitment threshold and firing rate of the same motor unit differed when recruited involuntarily via reflex or voluntarily via descending spinal pathways. Although Ia input is excitatory to the alpha-motoneuron pool, it has also been shown paradoxically to inhibit itself. Our second purpose was to determine if vibration of the patellar tendon during a voluntary knee extension causes a change in the firing rate of already recruited motor units. In the first protocol, 10 subjects voluntarily reproduced the same isometric force profile of the knee extensors that was elicited by vibration of the patellar tendon. Single motor unit recordings from the vastus lateralis (VL) were obtained with tungsten microelectrodes and unitary behaviour was examined during both reflex and voluntary knee extensions. Recordings from 135 single motor units showed that both recruitment thresholds and firing rates were lower during reflex contractions. In the second protocol, 7 subjects maintained a voluntary knee extension at 30 N for approximately 40-45 s. Three bursts of patellar tendon vibration were superimposed at regular intervals throughout the contraction and changes in the firing rate of already recruited motor units were examined. A total of 35 motor units were recorded and each burst of superimposed vibration caused a momentary reduction in the firing rates and recruitment of additional units. Our data provide evidence that Ia input modulates the recruitment thresholds and firing rates of motor units providing more flexibility within the neuromuscular system to grade force at low levels of force production.

  17. The (B)link Between Creativity and Dopamine: Spontaneous Eye Blink Rates Predict and Dissociate Divergent and Convergent Thinking

    Science.gov (United States)

    Chermahini, Soghra Akbari; Hommel, Bernhard

    2010-01-01

    Human creativity has been claimed to rely on the neurotransmitter dopamine, but evidence is still sparse. We studied whether individual performance (N=117) in divergent thinking (alternative uses task) and convergent thinking (remote association task) can be predicted by the individual spontaneous eye blink rate (EBR), a clinical marker of…

  18. Vastus Lateralis Motor Unit Firing Rate Is Higher in Women With Patellofemoral Pain.

    Science.gov (United States)

    Gallina, Alessio; Hunt, Michael A; Hodges, Paul W; Garland, S Jayne

    2018-05-01

    To compare neural drive, determined from motor unit firing rate, in the vastus medialis and lateralis in women with and without patellofemoral pain. Cross-sectional study. University research laboratory. Women (N=56) 19 to 35 years of age, including 36 with patellofemoral pain and 20 controls. Not applicable. Participants sustained an isometric knee extension contraction at 10% of their maximal voluntary effort for 70 seconds. Motor units (N=414) were identified using high-density surface electromyography. Average firing rate was calculated between 5 and 35 seconds after recruitment for each motor unit. Initial firing rate was the inverse of the first 3 motor unit interspike intervals. In control participants, vastus medialis motor units discharged at higher rates than vastus lateralis motor units (P=.001). This was not observed in women with patellofemoral pain (P=.78) because of a higher discharge rate of vastus lateralis compared with control participants (P=.002). No between-group differences were observed for vastus medialis (P=.93). Similar results were obtained for the initial motor unit firing rate. These findings suggest that women with patellofemoral pain have a higher neural drive to vastus lateralis but not vastus medialis, which may be a contributor of the altered patellar kinematics observed in some studies. The different neural drive may be an adaptation to patellofemoral pain, possibly to compensate for decreased quadriceps force production, or a precursor of patellofemoral pain. Copyright © 2018 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  19. Probe Measurements of Ash Deposit Formation Rate and Shedding in a Biomass Suspension-Fired boiler

    DEFF Research Database (Denmark)

    Shafique Bashir, Muhammad; Jensen, Peter Arendt; Frandsen, Flemming

    The aim of this study was to investigate ash deposit formation rate, heat uptake reduction and deposit removal by using advanced online ash deposition and sootblowing probes in a 350 MWth suspension-fired boiler, utilizing wood and straw pellets as fuel. The influence of fuel type (straw share...

  20. Motor unit firing rates during spasms in thenar muscles of spinal cord injured subjects

    NARCIS (Netherlands)

    Zijdewind, Inge; Bakels, Robert; Thomas, Christine K.

    2014-01-01

    Involuntary contractions of paralyzed muscles (spasms) commonly disrupt daily activities and rehabilitation after human spinal cord injury (SCI). Our aim was to examine the recruitment, firing rate modulation, and derecruitment of motor units that underlie spasms of thenar muscles after cervical

  1. Variance in population firing rate as a measure of slow time-scale correlation

    Directory of Open Access Journals (Sweden)

    Adam C. Snyder

    2013-12-01

    Full Text Available Correlated variability in the spiking responses of pairs of neurons, also known as spike count correlation, is a key indicator of functional connectivity and a critical factor in population coding. Underscoring the importance of correlation as a measure for cognitive neuroscience research is the observation that spike count correlations are not fixed, but are rather modulated by perceptual and cognitive context. Yet while this context fluctuates from moment to moment, correlation must be calculated over multiple trials. This property undermines its utility as a dependent measure for investigations of cognitive processes which fluctuate on a trial-to-trial basis, such as selective attention. A measure of functional connectivity that can be assayed on a moment-to-moment basis is needed to investigate the single-trial dynamics of populations of spiking neurons. Here, we introduce the measure of population variance in normalized firing rate for this goal. We show using mathematical analysis, computer simulations and in vivo data how population variance in normalized firing rate is inversely related to the latent correlation in the population, and how this measure can be used to reliably classify trials from different typical correlation conditions, even when firing rate is held constant. We discuss the potential advantages for using population variance in normalized firing rate as a dependent measure for both basic and applied neuroscience research.

  2. NFDRSPC: The National Fire-Danger Rating System on a Personal Computer

    Science.gov (United States)

    Bryan G. Donaldson; James T. Paul

    1990-01-01

    This user's guide is an introductory manual for using the 1988 version (Burgan 1988) of the National Fire-Danger Rating System on an IBM PC or compatible computer. NFDRSPC is a window-oriented, interactive computer program that processes observed and forecast weather with fuels data to produce NFDRS indices. Other program features include user-designed display...

  3. Influence of the contractile properties of muscle on motor unit firing rates during a moderate-intensity contraction in vivo.

    Science.gov (United States)

    Trevino, Michael A; Herda, Trent J; Fry, Andrew C; Gallagher, Philip M; Vardiman, John P; Mosier, Eric M; Miller, Jonathan D

    2016-08-01

    It is suggested that firing rate characteristics of motor units (MUs) are influenced by the physical properties of the muscle. However, no study has correlated MU firing rates at recruitment, targeted force, or derecruitment with the contractile properties of the muscle in vivo. Twelve participants (age = 20.67 ± 2.35 yr) performed a 40% isometric maximal voluntary contraction of the leg extensors that included linearly increasing, steady force, and decreasing segments. Muscle biopsies were collected with myosin heavy chain (MHC) content quantified, and surface electromyography (EMG) was recorded from the vastus lateralis. The EMG signal was decomposed into the firing events of single MUs. Slopes and y-intercepts were calculated for 1) firing rates at recruitment vs. recruitment threshold, 2) mean firing rates at steady force vs. recruitment threshold, and 3) firing rates at derecruitment vs. derecruitment threshold relationships for each subject. Correlations among type I %MHC isoform content and the slopes and y-intercepts from the three relationships were examined. Type I %MHC isoform content was correlated with MU firing rates at recruitment (y-intercepts: r = -0.577; slopes: r = 0.741) and targeted force (slopes: r = 0.853) vs. recruitment threshold and MU firing rates at derecruitment (y-intercept: r = -0.597; slopes: r = 0.701) vs. derecruitment threshold relationships. However, the majority of the individual MU firing rates vs. recruitment and derecruitment relationships were not significant (P > 0.05) and, thus, revealed no systematic pattern. In contrast, MU firing rates during the steady force demonstrated a systematic pattern with higher firing rates for the lower- than higher-threshold MUs and were correlated with the physical properties of MUs in vivo. Copyright © 2016 the American Physiological Society.

  4. Analysis of the influence of operating conditions on fouling rates in fired heaters

    International Nuclear Information System (INIS)

    Morales-Fuentes, A.; Picón-Núñez, M.; Polley, G.T.; Méndez-Díaz, S.

    2014-01-01

    Fouling due to chemical reaction in preheat trains for the processing of crude oil plays a key role in the operation and maintenance costs and on greenhouse emissions to atmosphere in crude processing plants. A preheat train consists of a set of heat transfer units that provide the crude oil stream the required amount of thermal energy to reach its target temperature either by heat recovery or by direct firing. Fired heaters supply external high temperature heating through the burning of fuel which result in complex heat transfer processes due to the large temperature and pressure changes and vaporization that takes place inside the unit. In this work, a thermo-hydraulic analysis of the performance of fired heaters is carried out through the application of commercial software to solve the mathematical models using finite difference methods; the analysis is applied to the crude side of a vertical fired heater in order to evaluate the impact of process conditions such as throughput and crude inlet temperature (CIT) on the fouling that take place at the early stages of operation. Using a fouling rate model based on thermo-hydraulic parameters, fouling rates are predicted assuming steady state operation and clean conditions. Although variations in process conditions are known to influence fouling rates, little work has been done on the subject. In this work excess air and steam injection are studied as a means to mitigate fouling. Results show that throughput reduction brings about a marked increase in the fouling rates. A decrease in CIT affects only the convection zone and it is found that this effect is negligible. In terms of excess air, it is found that although it affects negatively the heater efficiency it can be used to balance heat transfer between the convection and radiation zone in a way that fouling rates are reduced; however this strategy should be considered right from the design stage. Finally it is observed that steam injection is an effective method

  5. Spontaneous first trimester miscarriage rates per woman among parous women with 1 or more pregnancies of 24 weeks or more.

    Science.gov (United States)

    Cohain, Judy Slome; Buxbaum, Rina E; Mankuta, David

    2017-12-22

    The purpose of this study was to quantify spontaneous first trimester miscarriage rates per woman among parous women. A vast amount of data has accumulated regarding miscarriage rates per recognized pregnancy as well as about recurrent miscarriage. This is the second study of miscarriage rates per woman in a parous population and the first study of recurrent and non-recurrent, spontaneous first trimester miscarriage rates per woman in a large parous population. Extraction of the following variables from all delivery room admissions from both Hadassah Medical Centers in Jerusalem Israel, 2004-2014: # of first trimester spontaneous miscarriages, # live births; # living children; age on admission, pre-pregnancy height and weight, any smoking this pregnancy, any alcohol or drug abuse this pregnancy, blood type, history of ectopic pregnancy, history of cesarean surgery (CS) and use of any fertility treatment(s). Among 53,479 different women admitted to labor and delivery ward, 43% of women reported having had 1 or more first trimester spontaneous miscarriages; 27% reported having had one, 10% two, 4% three, 1.3% four, 0.6% five and 0.05% reported having 6-16 spontaneous first trimester miscarriages. 18.5% had one or more first trimester miscarriages before their first live birth. Eighty-one percent of women with 11 or more living children experienced one or more first trimester miscarriages. First trimester miscarriage rates rose with increasing age, increasing parity, after previous ectopic pregnancy, after previous cesarean surgery, with any smoking during pregnancy and pre-pregnancy BMI ≥30. Miscarriages are common among parous women; 43% of parous women report having experienced one or more first trimester spontaneous miscarriages, rising to 81% among women with 11 or more living children. One in every 17 parous women have three or more miscarriages. Depending on her health, nutrition and lifestyle choices, even a 39 year old parous woman with a history of 3 or

  6. Cortical Network Models of Firing Rates in the Resting and Active States Predict BOLD Responses.

    Directory of Open Access Journals (Sweden)

    Maxwell R Bennett

    Full Text Available Measurements of blood oxygenation level dependent (BOLD signals have produced some surprising observations. One is that their amplitude is proportional to the entire activity in a region of interest and not just the fluctuations in this activity. Another is that during sleep and anesthesia the average BOLD correlations between regions of interest decline as the activity declines. Mechanistic explanations of these phenomena are described here using a cortical network model consisting of modules with excitatory and inhibitory neurons, taken as regions of cortical interest, each receiving excitatory inputs from outside the network, taken as subcortical driving inputs in addition to extrinsic (intermodular connections, such as provided by associational fibers. The model shows that the standard deviation of the firing rate is proportional to the mean frequency of the firing when the extrinsic connections are decreased, so that the mean BOLD signal is proportional to both as is observed experimentally. The model also shows that if these extrinsic connections are decreased or the frequency of firing reaching the network from the subcortical driving inputs is decreased, or both decline, there is a decrease in the mean firing rate in the modules accompanied by decreases in the mean BOLD correlations between the modules, consistent with the observed changes during NREM sleep and under anesthesia. Finally, the model explains why a transient increase in the BOLD signal in a cortical area, due to a transient subcortical input, gives rises to responses throughout the cortex as observed, with these responses mediated by the extrinsic (intermodular connections.

  7. A 3D vision system for the measurement of the rate of spread and the height of fire fronts

    International Nuclear Information System (INIS)

    Rossi, L; Molinier, T; Tison, Y; Pieri, A; Akhloufi, M

    2010-01-01

    This paper presents a three-dimensional (3D) vision-based instrumentation system for the measurement of the rate of spread and height of complex fire fronts. The proposed 3D imaging system is simple, does not require calibration, is easily deployable in indoor and outdoor environments and can handle complex fire fronts. New approaches for measuring the position, the rate of spread and the height of a fire front during its propagation are introduced. Experiments were conducted in indoor and outdoor conditions with fires of different scales. Linear and curvilinear fire front spreading were studied. The obtained results are promising and show the interesting performance of the proposed system in operational and complex fire scenarios

  8. Inhibition linearizes firing rate responses in human motor units: implications for the role of persistent inward currents.

    Science.gov (United States)

    Revill, Ann L; Fuglevand, Andrew J

    2017-01-01

    Motor neurons are the output neurons of the central nervous system and are responsible for controlling muscle contraction. When initially activated during voluntary contraction, firing rates of motor neurons increase steeply but then level out at modest rates. Activation of an intrinsic source of excitatory current at recruitment onset may underlie the initial steep increase in firing rate in motor neurons. We attempted to disable this intrinsic excitatory current by artificially activating an inhibitory reflex. When motor neuron activity was recorded while the inhibitory reflex was engaged, firing rates no longer increased steeply, suggesting that the intrinsic excitatory current was probably responsible for the initial sharp rise in motor neuron firing rate. During graded isometric contractions, motor unit (MU) firing rates increase steeply upon recruitment but then level off at modest rates even though muscle force continues to increase. The mechanisms underlying such firing behaviour are not known although activation of persistent inward currents (PICs) might be involved. PICs are intrinsic, voltage-dependent currents that activate strongly when motor neurons (MNs) are first recruited. Such activation might cause a sharp escalation in depolarizing current and underlie the steep initial rise in MU firing rate. Because PICs can be disabled with synaptic inhibition, we hypothesized that artificial activation of an inhibitory pathway might curb this initial steep rise in firing rate. To test this, human subjects performed slow triangular ramp contractions of the ankle dorsiflexors in the absence and presence of tonic synaptic inhibition delivered to tibialis anterior (TA) MNs by sural nerve stimulation. Firing rate profiles (expressed as a function of contraction force) of TA MUs recorded during these tasks were compared for control and stimulation conditions. Under control conditions, during the ascending phase of the triangular contractions, 93% of the firing

  9. Effect of longwall face advance rate on spontaneous heating process in the gob area - CFD modelling

    Czech Academy of Sciences Publication Activity Database

    Taraba, B.; Michalec, Zdeněk

    2011-01-01

    Roč. 90, č. 8 (2011), s. 2790-2797 ISSN 0016-2361 R&D Projects: GA ČR GA105/06/0630 Grant - others:GA ČR(CZ) GA105/08/1414 Institutional research plan: CEZ:AV0Z30860518 Keywords : coal oxidation * spontaneous heating * CFD modelling * Fluent Subject RIV: DH - Mining, incl. Coal Mining Impact factor: 3.248, year: 2011 http://www.sciencedirect.com/science/article/pii/S0016236111001724

  10. Reduced firing rates of high threshold motor units in response to eccentric overload.

    Science.gov (United States)

    Balshaw, Tom G; Pahar, Madhu; Chesham, Ross; Macgregor, Lewis J; Hunter, Angus M

    2017-01-01

    Acute responses of motor units were investigated during submaximal voluntary isometric tasks following eccentric overload (EO) and constant load (CL) knee extension resistance exercise. Ten healthy resistance-trained participants performed four experimental test sessions separated by 5 days over a 20 day period. Two sessions involved constant load and the other two used eccentric overload. EO and CL used both sessions for different target knee eccentric extension phases; one at 2 sec and the other at 4 sec. Maximal voluntary contractions (MVC) and isometric trapezoid efforts for 10 sec at 70% MVC were completed before and after each intervention and decomposed electromyography was used to measure motor unit firing rate. The firing rate of later recruited, high-threshold motor units declined following the 2-sec EO but was maintained following 2sec CL (P motor units were maintained for both loading types following 4-sec extension phases. MVC and rate of force development where maintained following both EO and CL and 2 and 4 sec phases. This study demonstrates a slower firing rate of high-threshold motor units following fast eccentric overload while MVC was maintained. This suggests that there was a neuromuscular stimulus without cost to the force-generating capacity of the knee extensors. © 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

  11. Peatland Fire Danger Rating According to Weeds Characteristic Under Jelutung (Dyera Polyphylla Plantation

    Directory of Open Access Journals (Sweden)

    Acep Akbar

    2016-04-01

    Full Text Available Besides to be a competitor plant, weeds could act as the potential fuel under plantation forest in peatland. Characteristic of weeds in relation to peat swamp forest fire danger was studied under jelutung  plantation in Central Kalimantan. The research was aimed at exploring the potency of weed to become one of the fire danger rating indicators. By using vegetation analyses method in sampling unit of weeds population, results showed that three plantation area have different dominance weed species. The weeds species that could be the indicator of height fire risk according to water content and percentage of weed mortality during the drought, height potency of greenhouse gas emmision, culm height, and chemical material content that easy burned in this study were Imperata cylindrica, Stenochlaena polustris, Cyclosorus aridus, and Nephrolepis exaltata. While, the presence of Glichenia linearis, Melastoma malabatracum, Ficus grossulariodes, Saurophus androginus, Spatoglathis plicata,Himenocalis littoralis, Leptaspis urcheolata, Cyperus rotundus, and Amaranthus spinosa were not indicated high fire risk.

  12. Normalization of water flow rate for external fire fighting of the buildings in settlements with zone water supply

    Directory of Open Access Journals (Sweden)

    Deryushev Leonid Georgievich

    2014-12-01

    Full Text Available In the article the requirements for fire safety assurance are justified for the objects, in which water is supplied with account for serial and parallel area zoning. In the process of zoning the district is segregated into such parts, for which head rate in any point of selection of water from network will not exceed 6 bar. In the current regulatory rules the requirements for the calculation of the costs of water points are stated, as well as in case of extinguishing fires at the sites with water-supply systems zones. It is recommended to analyze each zone of the system of water-supply separately, without interrelation with the common water feeders, water consumers and services of fire extinguishing. Such an approach to assign water discharge for fire extinguishing results in the decrease of fire safety of an object, deforms calculation technique of outside systems of water-supply of the similar-type objects located in different parts of the terrain. Taking the number of fires and water consumption for fire suppression by the number of residents in each zone, we thus underestimate the capacity of the pipeline system. It is offered to make changes in Norms and Standards in force on fire safety of settlements. The recommendations on regulation of the number of fires and water flow for fire fighting in residential objects with zoned systems of water-supply are formulated.

  13. Fire scar growth and closure rates in white oak (Quercus alba) and the implications for prescribed burning

    Science.gov (United States)

    Michael C. Stambaugh; Kevin T. Smith; Daniel C. Dey

    2017-01-01

    In burned forestlands, fire scar wounds commonly occur on tree stems as a result of cambial heating. In hardwood forests in particular, wounding can lead to stem decay with the extent of decay being related to scar size and exposure time. Therefore, wound closure rates are important to understand in the context of fire management such that allowing sufficient time for...

  14. Mitochondrial Mutation Rate, Spectrum and Heteroplasmy in Caenorhabditis elegans Spontaneous Mutation Accumulation Lines of Differing Population Size.

    Science.gov (United States)

    Konrad, Anke; Thompson, Owen; Waterston, Robert H; Moerman, Donald G; Keightley, Peter D; Bergthorsson, Ulfar; Katju, Vaishali

    2017-06-01

    Mitochondrial genomes of metazoans, given their elevated rates of evolution, have served as pivotal markers for phylogeographic studies and recent phylogenetic events. In order to determine the dynamics of spontaneous mitochondrial mutations in small populations in the absence and presence of selection, we evolved mutation accumulation (MA) lines of Caenorhabditis elegans in parallel over 409 consecutive generations at three varying population sizes of N = 1, 10, and 100 hermaphrodites. The N =1 populations should have a minimal influence of natural selection to provide the spontaneous mutation rate and the expected rate of neutral evolution, whereas larger population sizes should experience increasing intensity of selection. New mutations were identified by Illumina paired-end sequencing of 86 mtDNA genomes across 35 experimental lines and compared with published genomes of natural isolates. The spontaneous mitochondrial mutation rate was estimated at 1.05 × 10-7/site/generation. A strong G/C→A/T mutational bias was observed in both the MA lines and the natural isolates. This suggests that the low G + C content at synonymous sites is the product of mutation bias rather than selection as previously proposed. The mitochondrial effective population size per worm generation was estimated to be 62. Although it was previously concluded that heteroplasmy was rare in C. elegans, the vast majority of mutations in this study were heteroplasmic despite an experimental regime exceeding 400 generations. The frequencies of frameshift and nonsynonymous mutations were negatively correlated with population size, which suggests their deleterious effects on fitness and a potent role for selection in their eradication. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  15. Effect of spontaneous saliva swallowing on short-term heart rate variability (HRV) and reliability of HRV analysis.

    Science.gov (United States)

    Yildiz, Metin; Doma, Serian

    2017-09-26

    The effects of effortful swallowing and solid meal ingestions on heart rate variability (HRV) have been examined previously. The effects of spontaneous saliva swallowing on short-term HRV and reliability of HRV analysis have not been studied before. The effect of saliva swallowing on HRV analyses parameters [meanRRI, SDNN (standard deviation of normal-to-normal), LF (low frequency), HF (high frequency) powers, LH/HF] and the reliability of LF and HF powers were investigated by frequency, time-frequency and intraclass correlation coefficient (ICC) analyses. Electrocardiogram and swallowing signal that obtained from an electronic stethoscope placed on the necks of subjects were recorded simultaneously from 30 healthy and young volunteers in sitting position during 15 min. Spontaneous swallowing has been shown to significantly alter some HRV parameters (SDNN, LF power and LF/HF ratio). Time-frequency analysis results showed that the contribution of saliva swallowing to LF (1-58%) and HF (2-42%) powers could change significantly depending on the number of swallowing. The ICC of the LF and HF powers for the successive 5-min signal segments were found 0·89, 0·92, respectively. These values decreased to 0·73 and 0·90 in the subjects with more swallowing rate. When the analyses were made for 2-min signal periods, these values decreased to 0·63 and 0·67. We concluded that spontaneous saliva swallowing can change HRV parameters. We have also seen that changes in swallowing rate and use of short signal segments may reduce the reliability of HRV analyses. © 2017 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  16. High rate of hepatitis C virus (HCV) recurrence in HIV-infected individuals with spontaneous HCV RNA clearance

    DEFF Research Database (Denmark)

    Peters, L; Mocroft, A; Soriano, V

    2014-01-01

    OBJECTIVES: Following resolution of hepatitis C virus (HCV) infection, recurrence has been shown to occur in some persons with repeated exposure to HCV. We aimed to investigate the rate and factors associated with HCV RNA recurrence among HIV-1-infected patients with prior spontaneous HCV RNA cle......-up. Our findings underline the importance of maintaining focus on preventive measures to reduce IDU and sharing of contaminated needles. Clinicians should maintain a high degree of vigilance to identify patients with new HCV infection early....

  17. Comment on anomalous dispersion and scattering rates for multiphonon spontaneous decay in He II

    Science.gov (United States)

    Haavasoja, T.; Narayanamurti, V.; Chin, M. A.

    1984-10-01

    We report on new measurements of the spontaneous decay threshold energy E c for high-frequency phonon propagation in He II at saturated vapor pressure at T=0.1 K. Superconducting tin tunnel generators and aluminum tunnel detectors were used in this study. The measurements show that the mean free path becomes much larger than the propagation length of 1.1 mm for a value of E c =9.8±0.15 K. This agrees with the value originally reported ( E c =9.5±0.4 K) by Dynes and Narayanamurti using aluminum tunnel generators, but is shown to correspond to the point where the phase velocity equals the sound velocity, when the phonons become stable, as first proposed by Pitayevski and Levinson. Evidence for n-phonon decay at energies lower than E c is presented for n≳2 with a short mean free path (neutron data due to Donnelly, Donnelly, and Hills.

  18. The effects of MSH2 deficiency on spontaneous and radiation-induced mutation rates in the mouse germline

    International Nuclear Information System (INIS)

    Burr, Karen L-A.; Duyn-Goedhart, Annemarie van; Hickenbotham, Peter; Monger, Karen; Buul, Paul P.W. van; Dubrova, Yuri E.

    2007-01-01

    Mutation rates at two expanded simple tandem repeat (ESTR) loci were studied in the germline of mismatch repair deficient Msh2 knock-out mice. Spontaneous mutation rates in homozygous Msh2 -/- males were significantly higher than those in isogenic wild-type (Msh2 +/+ ) and heterozygous (Msh2 +/- ) mice. In contrast, the irradiated Msh2 -/- mice did not show any detectable increases in their mutation rate, whereas significant ESTR mutation induction was observed in the irradiated Msh2 +/+ and Msh2 +/- animals. Considering these data and the results of other publications, we propose that the Msh2-deficient mice possess a mutator phenotype in their germline and somatic tissues while the loss of a single Msh2 allele does not affect the stability of heterozygotes

  19. Dynamical Properties of Discrete-Time Background Neural Networks with Uniform Firing Rate

    Directory of Open Access Journals (Sweden)

    Min Wan

    2013-01-01

    Full Text Available The dynamics of a discrete-time background network with uniform firing rate and background input is investigated. The conditions for stability are firstly derived. An invariant set is then obtained so that the nondivergence of the network can be guaranteed. In the invariant set, it is proved that all trajectories of the network starting from any nonnegative value will converge to a fixed point under some conditions. In addition, bifurcation and chaos are discussed. It is shown that the network can engender bifurcation and chaos with the increase of background input. The computations of Lyapunov exponents confirm the chaotic behaviors.

  20. Contractile function and motor unit firing rates of the human hamstrings.

    Science.gov (United States)

    Kirk, Eric A; Rice, Charles L

    2017-01-01

    Neuromuscular properties of the lower limb in health, aging, and disease are well described for major lower limb muscles comprising the quadriceps, triceps surae, and dorsiflexors, with the notable exception of the posterior thigh (hamstrings). The purpose of this study was to further characterize major muscles of the lower limb by comprehensively exploring contractile properties in relation to spinal motor neuron output expressed as motor unit firing rates (MUFRs) in the hamstrings of 11 (26.5 ± 3.8) young men. Maximal isometric voluntary contraction (MVC), voluntary activation, stimulated contractile properties including a force-frequency relationship, and MUFRs from submaximal to maximal voluntary contractile intensities were assessed in the hamstrings. Strength and MUFRs were assessed at two presumably different muscle lengths by varying the knee joint angles (90° and 160°). Knee flexion MVCs were 60-70% greater in the extended position (160°). The frequency required to elicit 50% of maximum tetanic torque was 16-17 Hz. Mean MUFRs at 25-50% MVC were 9-31% less in the biceps femoris compared with the semimembranosus-semitendinosus group. Knee joint angle (muscle length) influenced MUFRs such that mean MUFRs were greater in the shortened (90°) position at 50% and 100% MVC. Compared with previous reports, mean maximal MUFRs in the hamstrings are greater than those in the quadriceps and triceps surae and somewhat less than those in the tibialis anterior. Mean maximal MUFRs in the hamstrings are influenced by changes in knee joint angle, with lower firing rates in the biceps femoris compared with the semimembranosus-semitendinosus muscle group. We studied motor unit firing rates (MUFRs) at various voluntary contraction intensities in the hamstrings, one of the only major lower limb muscles to have MUFRs affected by muscle length changes. Within the hamstrings muscle-specific differences have greater impact on MUFRs than length changes, with the biceps femoris

  1. Smoke Movement in an Atrium with a Fire with Low Rate of Heat Release

    DEFF Research Database (Denmark)

    Nielsen, Peter V.; Brohus, Henrik; Petersen, A. J.

    2008-01-01

    Results from small-scale experiments on smoke movement in an atrium are given, both with and without a vertical temperature gradient, and expressions for the smoke movement are developed on the basis of these experiments. Comparisons with a general analytical expression used for calculating...... the height to the location of the smoke layer are given. Furthermore, the paper discusses the air movement in a typical atrium exposed to different internal and external heat loads to elaborate on the use of the "flow element" expressions developed for smoke movement from a fire with a low rate of heat...

  2. Lognormal firing rate distribution reveals prominent fluctuation-driven regime in spinal motor networks

    DEFF Research Database (Denmark)

    Petersen, Peter C.; Berg, Rune W.

    2016-01-01

    fraction that operates within either a ‘mean-driven’ or a ‘fluctuation–driven’ regime. Fluctuation-driven neurons have a ‘supralinear’ input-output curve, which enhances sensitivity, whereas the mean-driven regime reduces sensitivity. We find a rich diversity of firing rates across the neuronal population...... as reflected in a lognormal distribution and demonstrate that half of the neurons spend at least 50 %% of the time in the ‘fluctuation–driven’ regime regardless of behavior. Because of the disparity in input–output properties for these two regimes, this fraction may reflect a fine trade–off between stability...

  3. Quantifying collective effervescence: Heart-rate dynamics at a fire-walking ritual

    DEFF Research Database (Denmark)

    Xygalatas, Dimitris; Konvalinka, Ivana; Roepstorff, Andreas

    2011-01-01

    Collective rituals are ubiquitous and resilient features of all known human cultures. They are also functionally opaque, costly, and sometimes dangerous. Social scientists have speculated that collective rituals generate benefits in excess of their costs by reinforcing social bonding and group...... solidarity, yet quantitative evidence for these conjectures is scarce. Our recent study measured the physiological effects of a highly arousing Spanish fire-walking ritual, revealing shared patterns in heart-rate dynamics between participants and related spectators. We briefly describe our results...

  4. Short and Long-Term Attentional Firing Rates Can Be Explained by ST-Neuron Dynamics

    Directory of Open Access Journals (Sweden)

    Oscar J. Avella Gonzalez

    2018-03-01

    Full Text Available Attention modulates neural selectivity and optimizes the allocation of cortical resources during visual tasks. A large number of experimental studies in primates and humans provide ample evidence. As an underlying principle of visual attention, some theoretical models suggested the existence of a gain element that enhances contrast of the attended stimuli. In contrast, the Selective Tuning model of attention (ST proposes an attentional mechanism based on suppression of irrelevant signals. In this paper, we present an updated characterization of the ST-neuron proposed by the Selective Tuning model, and suggest that the inclusion of adaptation currents (Ih to ST-neurons may explain the temporal profiles of the firing rates recorded in single V4 cells during attentional tasks. Furthermore, using the model we show that the interaction between stimulus-selectivity of a neuron and attention shapes the profile of the firing rate, and is enough to explain its fast modulation and other discontinuities observed, when the neuron responds to a sudden switch of stimulus, or when one stimulus is added to another during a visual task.

  5. Analytical approximations of the firing rate of an adaptive exponential integrate-and-fire neuron in the presence of synaptic noise

    Directory of Open Access Journals (Sweden)

    Loreen eHertäg

    2014-09-01

    Full Text Available Computational models offer a unique tool for understanding the network-dynamical mechanisms which mediate between physiological and biophysical properties, and behavioral function. A traditional challenge in computational neuroscience is, however, that simple neuronal models which can be studied analytically fail to reproduce the diversity of electrophysiological behaviors seen in real neurons, while detailed neuronal models which do reproduce such diversity are intractable analytically and computationally expensive. A number of intermediate models have been proposed whose aim is to capture the diversity of firing behaviors and spike times of real neurons while entailing a mathematical description as simple as possible. One such model is the exponential integrate-and-fire neuron with spike rate adaptation (aEIF which consists of two differential equations for the membrane potential (V and an adaptation current (w. Despite its simplicity, it can reproduce a wide variety of physiologically observed spiking patterns, can be fit to physiological recordings quantitatively, and, once done so, is able to predict spike times on traces not used for model fitting. Here we compute the steady-state firing rate of aEIF in the presence of Gaussian synaptic noise, using two approaches. The first approach is based on the 2-dimensional Fokker-Planck equation that describes the (V,w-probability distribution, which is solved using an expansion in the ratio between the time constants of the two variables. The second is based on the firing rate of the EIF model, which is averaged over the distribution of the $w$ variable. These analytically derived closed-form expressions were tested on simulations from a large variety of model cells quantitatively fitted to in vitro electrophysiological recordings from pyramidal cells and interneurons. Theoretical predictions closely agreed with the firing rate of the simulated cells fed with in-vivo-like synaptic noise.

  6. Analytical approximations of the firing rate of an adaptive exponential integrate-and-fire neuron in the presence of synaptic noise.

    Science.gov (United States)

    Hertäg, Loreen; Durstewitz, Daniel; Brunel, Nicolas

    2014-01-01

    Computational models offer a unique tool for understanding the network-dynamical mechanisms which mediate between physiological and biophysical properties, and behavioral function. A traditional challenge in computational neuroscience is, however, that simple neuronal models which can be studied analytically fail to reproduce the diversity of electrophysiological behaviors seen in real neurons, while detailed neuronal models which do reproduce such diversity are intractable analytically and computationally expensive. A number of intermediate models have been proposed whose aim is to capture the diversity of firing behaviors and spike times of real neurons while entailing the simplest possible mathematical description. One such model is the exponential integrate-and-fire neuron with spike rate adaptation (aEIF) which consists of two differential equations for the membrane potential (V) and an adaptation current (w). Despite its simplicity, it can reproduce a wide variety of physiologically observed spiking patterns, can be fit to physiological recordings quantitatively, and, once done so, is able to predict spike times on traces not used for model fitting. Here we compute the steady-state firing rate of aEIF in the presence of Gaussian synaptic noise, using two approaches. The first approach is based on the 2-dimensional Fokker-Planck equation that describes the (V,w)-probability distribution, which is solved using an expansion in the ratio between the time constants of the two variables. The second is based on the firing rate of the EIF model, which is averaged over the distribution of the w variable. These analytically derived closed-form expressions were tested on simulations from a large variety of model cells quantitatively fitted to in vitro electrophysiological recordings from pyramidal cells and interneurons. Theoretical predictions closely agreed with the firing rate of the simulated cells fed with in-vivo-like synaptic noise.

  7. Fundamental limitations in spontaneous emission rate of single-photon sources

    DEFF Research Database (Denmark)

    Bozhevolnyi, Sergey I.; Khurgin, Jacob B.

    2016-01-01

    The rate of single-photon generation by quantum emitters (QEs) can be enhanced by placing a QE inside a resonant structure. This structure can represent an all-dielectric micro-resonator or waveguide and thus be characterized by ultra-low loss and dimensions on the order of wavelength. Or it can ...

  8. Interplay between spontaneous decay rates and Lamb shifts in open photonic systems

    Science.gov (United States)

    Lassalle, Emmanuel; Bonod, Nicolas; Durt, Thomas; Stout, Brian

    2018-05-01

    In this letter, we describe the modified decay rate and photonic Lamb (frequency) shift of quantum emitters in terms of the resonant states of a neighboring photonic resonator. This description illustrates a fundamental distinction in the behaviors of closed (conservative) and open (dissipative) systems: the Lamb shift is bounded by the emission linewidth in closed systems while it overcomes this limit in open systems.

  9. Increase of the spontaneous mutation rate in a long-term experiment with Drosophila melanogaster.

    Science.gov (United States)

    Avila, Victoria; Chavarrías, David; Sánchez, Enrique; Manrique, Antonio; López-Fanjul, Carlos; García-Dorado, Aurora

    2006-05-01

    In a previous experiment, the effect of 255 generations of mutation accumulation (MA) on the second chromosome viability of Drosophila melanogaster was studied using 200 full-sib MA1 lines and a large C1 control, both derived from a genetically homogeneous base population. At generation 265, one of those MA1 lines was expanded to start 150 new full-sib MA2 lines and a new C2 large control. After 46 generations, the rate of decline in mean viability in MA2 was approximately 2.5 times that estimated in MA1, while the average degree of dominance of mutations was small and nonsignificant by generation 40 and moderate by generation 80. In parallel, the inbreeding depression rate for viability and the amount of additive variance for two bristle traits in C2 were 2-3 times larger than those in C1. The results are consistent with a mutation rate in the line from which MA2 and C2 were derived about 2.5 times larger than that in MA1. The mean viability of C2 remained roughly similar to that of C1, but the rate of MA2 line extinction increased progressively, leading to mutational collapse, which can be ascribed to accelerated mutation and/or synergy after important deleterious accumulation.

  10. Cross Time-Frequency Analysis for Combining Information of Several Sources: Application to Estimation of Spontaneous Respiratory Rate from Photoplethysmography

    Science.gov (United States)

    Peláez-Coca, M. D.; Orini, M.; Lázaro, J.; Bailón, R.; Gil, E.

    2013-01-01

    A methodology that combines information from several nonstationary biological signals is presented. This methodology is based on time-frequency coherence, that quantifies the similarity of two signals in the time-frequency domain. A cross time-frequency analysis method, based on quadratic time-frequency distribution, has been used for combining information of several nonstationary biomedical signals. In order to evaluate this methodology, the respiratory rate from the photoplethysmographic (PPG) signal is estimated. The respiration provokes simultaneous changes in the pulse interval, amplitude, and width of the PPG signal. This suggests that the combination of information from these sources will improve the accuracy of the estimation of the respiratory rate. Another target of this paper is to implement an algorithm which provides a robust estimation. Therefore, respiratory rate was estimated only in those intervals where the features extracted from the PPG signals are linearly coupled. In 38 spontaneous breathing subjects, among which 7 were characterized by a respiratory rate lower than 0.15 Hz, this methodology provided accurate estimates, with the median error {0.00; 0.98} mHz ({0.00; 0.31}%) and the interquartile range error {4.88; 6.59} mHz ({1.60; 1.92}%). The estimation error of the presented methodology was largely lower than the estimation error obtained without combining different PPG features related to respiration. PMID:24363777

  11. Cross Time-Frequency Analysis for Combining Information of Several Sources: Application to Estimation of Spontaneous Respiratory Rate from Photoplethysmography

    Directory of Open Access Journals (Sweden)

    M. D. Peláez-Coca

    2013-01-01

    Full Text Available A methodology that combines information from several nonstationary biological signals is presented. This methodology is based on time-frequency coherence, that quantifies the similarity of two signals in the time-frequency domain. A cross time-frequency analysis method, based on quadratic time-frequency distribution, has been used for combining information of several nonstationary biomedical signals. In order to evaluate this methodology, the respiratory rate from the photoplethysmographic (PPG signal is estimated. The respiration provokes simultaneous changes in the pulse interval, amplitude, and width of the PPG signal. This suggests that the combination of information from these sources will improve the accuracy of the estimation of the respiratory rate. Another target of this paper is to implement an algorithm which provides a robust estimation. Therefore, respiratory rate was estimated only in those intervals where the features extracted from the PPG signals are linearly coupled. In 38 spontaneous breathing subjects, among which 7 were characterized by a respiratory rate lower than 0.15 Hz, this methodology provided accurate estimates, with the median error {0.00; 0.98} mHz ({0.00; 0.31}% and the interquartile range error {4.88; 6.59} mHz ({1.60; 1.92}%. The estimation error of the presented methodology was largely lower than the estimation error obtained without combining different PPG features related to respiration.

  12. Effectiveness of two contrasting mulching rates to reduce post-fire soil and organic matter losses

    Science.gov (United States)

    Silva, Flavio; Prats, Sergio; Vieira, Diana; Puga, João; Lopes, Rita; Gonzaléz-Pelayo, Oscar; Caetano, Ana; Campos, Isabel; Keizer, Jacob

    2017-04-01

    Wildfire-affected soils can reveal strong responses in runoff generation and associated soil (fertility) losses, thereby constituting a major threat to the typically shallow and poor forest soils of the Portuguese mountain areas. Mulching with logging residues from these forests has proven to provide a protective soil cover that is highly effective in reducing post-fire runoff and especially erosion (Prats et al., 2012, 2014, 2016a, 2016b). However, these past experiments have all applied comparatively large amounts of forest residues, in the order of 10 Mg ha-1, so that the relationship between application rate and effectiveness is still poorly known. Such relationship would nonetheless be of crucial importance for the employment of forest residue mulching in practice, as one of the possible emergency stabilization measures to be contemplated in post-fire land management of a recently-burned area. Further research gaps that exist in relation to post-fire forest residue mulching include its effectiveness in reducing soil fertility losses (C, N, P; Ferreira et al., 2016a, 2016b) and in minimizing export of contaminants (especially PAHs and metals; Campos et al., 2016), and its (secondary) impacts on soil biological activity and diversity (Puga et al., 2016) and on forest productivity (including through the addition of organic matter to the soil surface, partially replacing the burned litter layer; Prats et al. 2016b). In the framework of the EU-project RECARE, the effectiveness of two contrasting mulching rates with forest logging residues has been tested following a wildfire that on August 9th - 10th 2015 consumed some 715 ha of eucalypt plantations in the Semide municipality, central Portugal. Commercially-available logging residues (chopped bark and twigs) from eucalypt plantations were purchased, transported to the study site and applied to six out of nine 16 m2 erosion bounded plots that had been installed in a burned eucalypt plantation using a randomized

  13. A Tool for Rating the Resilience of Critical Infrastructures in Extreme Fires

    Science.gov (United States)

    2014-05-01

    Rapid Rise Fire Tests of Protection Materials for Structural Steel - Efectis Nederland Report – 2008-Efectis-R0695, Fire Testing Procedure for Concrete...extreme fire conditions such as ASTM E1529 [5], NFPA 502 [8], UL 1709 [4] and Efectis Nederland BV report [9]. One of the critical features of a

  14. Firing rate modulation of human motor units in different muscles during isometric contraction with various forces.

    Science.gov (United States)

    Seki, K; Narusawa, M

    1996-05-06

    To examine the factors affecting the control of human motor units, rate coding strategies of the motor units were investigated in upper limb and intrinsic hand muscles during voluntary isometric contraction of steady force levels up to 80% of maximal voluntary contraction. Numerous spike trains from single motor units were recorded from the m. first dorsal interosseous (FDI) and the m. biceps brachii (BB) of eight human subjects by means of tungsten micro-electrodes, and the mean firing rate (MFR) was calculated for each subject and inter-individual comparisons made. The MFRs of the FDI were larger than that of the BB at the higher force level, and substantial differences were not found between these muscles at the lower force level. The slope of the linear regression line of MFRs vs. exerted forces for the FDI was more than twice that for the BB. Therefore, isometric force control of the FDI depends more on the rate coding strategy. The difference in rate coding between the FDI and BB motor units may be determined by factors other than muscle fiber composition, because both muscles are known to possess a similar composition of fiber types. Possible mechanisms underlying these characteristics of rate coding strategy are considered in this report.

  15. Experimental characterization of true spontaneous emission rate of optically-pumped InGaAs/GaAs quantum-well laser structure

    Directory of Open Access Journals (Sweden)

    Q.-N. Yu

    2017-08-01

    Full Text Available In this paper, an experimental approach to acquiring true spontaneous emission rate of optically-pumped InGaAs/GaAs quantum-well laser structure is described. This method is based on a single edge-emitting laser chip with simple sample processing. The photoluminescence spectra are measured at both facets of the edge-emitting device and transformed to the spontaneous emission rate following the theory described here. The unusual double peaks appearing in the spontaneous emission rate spectra are observed for the InGaAs/GaAs quantum-well structure. The result is analyzed in terms of Indium-rich island and Model-Solid theories. The proposed method is suitable for electrically-pumped quantum-well laser structures, as well.

  16. Effects of Barbell Deadlift Training on Submaximal Motor Unit Firing Rates for the Vastus Lateralis and Rectus Femoris

    Science.gov (United States)

    Stock, Matt S.; Thompson, Brennan J.

    2014-01-01

    Previous investigations that have studied motor unit firing rates following strength training have been limited to small muscles, isometric training, or interventions involving exercise machines. We examined the effects of ten weeks of supervised barbell deadlift training on motor unit firing rates for the vastus lateralis and rectus femoris during a 50% maximum voluntary contraction (MVC) assessment. Twenty-four previously untrained men (mean age  = 24 years) were randomly assigned to training (n = 15) or control (n = 9) groups. Before and following the intervention, the subjects performed isometric testing of the right knee extensors while bipolar surface electromyographic signals were detected from the two muscles. The signals were decomposed into their constituent motor unit action potential trains, and motor units that demonstrated accuracy levels less than 92.0% were not considered for analysis. One thousand eight hundred ninety-two and 2,013 motor units were examined for the vastus lateralis and rectus femoris, respectively. Regression analyses were used to determine the linear slope coefficients (pulses per second [pps]/% MVC) and y-intercepts (pps) of the mean firing rate and firing rate at recruitment versus recruitment threshold relationships. Deadlift training significantly improved knee extensor MVC force (Cohen's d = .70), but did not influence force steadiness. Training had no influence on the slopes and y-intercepts for the mean firing rate and firing rate at recruitment versus recruitment threshold relationships. In agreement with previous cross-sectional comparisons and randomized control trials, our findings do not support the notion that strength training affects the submaximal control of motor units. PMID:25531294

  17. Effects of barbell deadlift training on submaximal motor unit firing rates for the vastus lateralis and rectus femoris.

    Directory of Open Access Journals (Sweden)

    Matt S Stock

    Full Text Available Previous investigations that have studied motor unit firing rates following strength training have been limited to small muscles, isometric training, or interventions involving exercise machines. We examined the effects of ten weeks of supervised barbell deadlift training on motor unit firing rates for the vastus lateralis and rectus femoris during a 50% maximum voluntary contraction (MVC assessment. Twenty-four previously untrained men (mean age  = 24 years were randomly assigned to training (n = 15 or control (n = 9 groups. Before and following the intervention, the subjects performed isometric testing of the right knee extensors while bipolar surface electromyographic signals were detected from the two muscles. The signals were decomposed into their constituent motor unit action potential trains, and motor units that demonstrated accuracy levels less than 92.0% were not considered for analysis. One thousand eight hundred ninety-two and 2,013 motor units were examined for the vastus lateralis and rectus femoris, respectively. Regression analyses were used to determine the linear slope coefficients (pulses per second [pps]/% MVC and y-intercepts (pps of the mean firing rate and firing rate at recruitment versus recruitment threshold relationships. Deadlift training significantly improved knee extensor MVC force (Cohen's d = .70, but did not influence force steadiness. Training had no influence on the slopes and y-intercepts for the mean firing rate and firing rate at recruitment versus recruitment threshold relationships. In agreement with previous cross-sectional comparisons and randomized control trials, our findings do not support the notion that strength training affects the submaximal control of motor units.

  18. Effects of barbell deadlift training on submaximal motor unit firing rates for the vastus lateralis and rectus femoris.

    Science.gov (United States)

    Stock, Matt S; Thompson, Brennan J

    2014-01-01

    Previous investigations that have studied motor unit firing rates following strength training have been limited to small muscles, isometric training, or interventions involving exercise machines. We examined the effects of ten weeks of supervised barbell deadlift training on motor unit firing rates for the vastus lateralis and rectus femoris during a 50% maximum voluntary contraction (MVC) assessment. Twenty-four previously untrained men (mean age  = 24 years) were randomly assigned to training (n = 15) or control (n = 9) groups. Before and following the intervention, the subjects performed isometric testing of the right knee extensors while bipolar surface electromyographic signals were detected from the two muscles. The signals were decomposed into their constituent motor unit action potential trains, and motor units that demonstrated accuracy levels less than 92.0% were not considered for analysis. One thousand eight hundred ninety-two and 2,013 motor units were examined for the vastus lateralis and rectus femoris, respectively. Regression analyses were used to determine the linear slope coefficients (pulses per second [pps]/% MVC) and y-intercepts (pps) of the mean firing rate and firing rate at recruitment versus recruitment threshold relationships. Deadlift training significantly improved knee extensor MVC force (Cohen's d = .70), but did not influence force steadiness. Training had no influence on the slopes and y-intercepts for the mean firing rate and firing rate at recruitment versus recruitment threshold relationships. In agreement with previous cross-sectional comparisons and randomized control trials, our findings do not support the notion that strength training affects the submaximal control of motor units.

  19. Determination by a CFD code of the heat release rate in a confined and mechanically-ventilated compartment fire

    International Nuclear Information System (INIS)

    Nasr, Ayoub

    2011-01-01

    For several years, many experimental/numerical research programs have been carried out at IRSN in order to provide sufficient data on the burning process and understand the behavior of a pool fire in a confined and mechanically ventilated compartment. Several experimental tests have shown that in some cases, the oxygen concentration in the local decreases then stabilizes until fire extinction. The fuel mass loss rate is instantaneously adjusted according to the ventilation in the local, which may leads to a lower fuel consumption rate as compared to that in free atmosphere. The fire duration is then 2 to 3 times greater than that obtained in free atmosphere, which may damages some specific safety equipment used to reduce the spread of fire between compartments such as fire doors. The objective of this work is to propose a theoretical approach that allows the determination of the burning rate of fuels for pool fires in a closed compartment. Fuel response to vitiated air as well as burning enhancement due to hot gases and confinement should be taken into account. Thus, a theoretical formulation, based on an energy balance equation at the pool fire surface, was developed and compared with the empirical correlation of Peatross and Beyler before being implemented in a CFD code 'ISIS', developed at IRSN and validated against PRISME fire test results. The main advantage of this global approach is that no assumptions were made on the relative importance of each mode of heat transfer from the flame. In fact, the convective and the radiant components of the heat flux from the flame to the fuel surface were determined taking into account the air vitiation effect. In addition to this theoretical approach, an experimental work was conducted at the Institut PPRIME to study heptane pool fires in a reduced-scale fire compartment, in the aim to investigate the effects of vitiated air on fire parameters. These results were used to validate the theoretical formulation developed

  20. Spontaneous mutation by mutagenic repair of spontaneous lesions in DNA

    International Nuclear Information System (INIS)

    Hastings, P.J.; Quah, S.-K.; Borstel, R.C. von

    1976-01-01

    It is stated that strains of yeast carrying mutations in many of the steps in pathways repairing radiation-induced damage to DNA have enhanced spontaneous mutation rates. Most strains isolated because they have enhanced spontaneous mutation carry mutations in DNA repair systems. This suggests that much spontaneous mutation arises by mutagenic repair of spontaneous lesions. (author)

  1. NK3 Receptors mediate an increase in firing rate of midbrain dopamine neurons of the rat and the guinea pig

    NARCIS (Netherlands)

    Werkman, T.R.; McCreary, A.C.; Kruse, C.G.; Wadman, W.J.

    2011-01-01

    This in vitro study investigates and compares the effects of NK3 receptor ligands on the firing rate of rat and guinea pig midbrain dopamine neurons. The findings are discussed in the light of choosing suitable animal models for investigating pharmacological properties of NK3 receptor antagonists,

  2. Do Additional Inputs Change Maximal Voluntary Motor Unit Firing Rates After Spinal Cord Injury?

    NARCIS (Netherlands)

    Zijdewind, Inge; Gant, Katie; Bakels, Rob; Thomas, Christine K.

    Background. Motor unit firing frequencies are low during maximal voluntary contractions (MVCs) of human thenar muscles impaired by cervical spinal cord injury (SCI). Objective. This study aimed to examine whether thenar motor unit firing frequencies increase when driven by both maximal voluntary

  3. Evaluating crown fire rate of spread predictions from physics-based models

    Science.gov (United States)

    C. M. Hoffman; J. Ziegler; J. Canfield; R. R. Linn; W. Mell; C. H. Sieg; F. Pimont

    2015-01-01

    Modeling the behavior of crown fires is challenging due to the complex set of coupled processes that drive the characteristics of a spreading wildfire and the large range of spatial and temporal scales over which these processes occur. Detailed physics-based modeling approaches such as FIRETEC and the Wildland Urban Interface Fire Dynamics Simulator (WFDS) simulate...

  4. Time-related changes in firing rates are influenced by recruitment threshold and twitch force potentiation in the first dorsal interosseous.

    Science.gov (United States)

    Miller, Jonathan D; Herda, Trent J; Trevino, Michael A; Sterczala, Adam J; Ciccone, Anthony B

    2017-08-01

    What is the central question of this study? The influences of motor unit recruitment threshold and twitch force potentiation on the changes in firing rates during steady-force muscular contractions are not well understood. What is the main finding and its importance? The behaviour of motor units during steady force was influenced by recruitment threshold, such that firing rates decreased for lower-threshold motor units but increased for higher-threshold motor units. In addition, individuals with greater changes in firing rates possessed greater twitch force potentiation. There are contradictory reports regarding changes in motor unit firing rates during steady-force contractions. Inconsistencies are likely to be the result of previous studies disregarding motor unit recruitment thresholds and not examining firing rates on a subject-by-subject basis. It is hypothesized that firing rates are manipulated by twitch force potentiation during contractions. Therefore, in this study we examined time-related changes in firing rates at steady force in relationship to motor unit recruitment threshold in the first dorsal interosseous and the influence of twitch force potentiation on such changes in young versus aged individuals. Subjects performed a 12 s steady-force contraction at 50% maximal voluntary contraction, with evoked twitches before and after the contraction to quantify potentiation. Firing rates, in relationship to recruitment thresholds, were determined at the beginning, middle and end of the steady force. There were no firing rate changes for aged individuals. For the young, firing rates decreased slightly for lower-threshold motor units but increased for higher-threshold motor units. Twitch force potentiation was greater for young than aged subjects, and changes in firing rates were correlated with twitch force potentiation. Thus, individuals with greater increases in firing rates of higher-threshold motor units and decreases in lower-threshold motor units

  5. RDX binds to the convulsant site of the GABAA receptor and increases spontaneous firing rates of cortical neurons in vitro

    Science.gov (United States)

    RDX (hexahydro-1 ,3,5-trinitro-1 ,3,5-triazine, hexogen, Royal Demolition eXplosive) is an explosive widely used by the military and has been found in soil and ground water in and surrounding training ranges, creating potential hazards to the environment and human health. Oral RD...

  6. Modelling Odor Decoding in the Antennal Lobe by Combining Sequential Firing Rate Models with Bayesian Inference.

    Directory of Open Access Journals (Sweden)

    Dario Cuevas Rivera

    2015-10-01

    Full Text Available The olfactory information that is received by the insect brain is encoded in the form of spatiotemporal patterns in the projection neurons of the antennal lobe. These dense and overlapping patterns are transformed into a sparse code in Kenyon cells in the mushroom body. Although it is clear that this sparse code is the basis for rapid categorization of odors, it is yet unclear how the sparse code in Kenyon cells is computed and what information it represents. Here we show that this computation can be modeled by sequential firing rate patterns using Lotka-Volterra equations and Bayesian online inference. This new model can be understood as an 'intelligent coincidence detector', which robustly and dynamically encodes the presence of specific odor features. We found that the model is able to qualitatively reproduce experimentally observed activity in both the projection neurons and the Kenyon cells. In particular, the model explains mechanistically how sparse activity in the Kenyon cells arises from the dense code in the projection neurons. The odor classification performance of the model proved to be robust against noise and time jitter in the observed input sequences. As in recent experimental results, we found that recognition of an odor happened very early during stimulus presentation in the model. Critically, by using the model, we found surprising but simple computational explanations for several experimental phenomena.

  7. Flame retardants in UK furniture increase smoke toxicity more than they reduce fire growth rate.

    Science.gov (United States)

    McKenna, Sean T; Birtles, Robert; Dickens, Kathryn; Walker, Richard G; Spearpoint, Michael J; Stec, Anna A; Hull, T Richard

    2018-04-01

    This paper uses fire statistics to show the importance of fire toxicity on fire deaths and injuries, and the importance of upholstered furniture and bedding on fatalities from unwanted fires. The aim was to compare the fire hazards (fire growth and smoke toxicity) using different upholstery materials. Four compositions of sofa-bed were compared: three meeting UK Furniture Flammability Regulations (FFR), and one using materials without flame retardants intended for the mainland European market. Two of the UK sofa-beds relied on chemical flame retardants to meet the FFR, the third used natural materials and a technical weave in order to pass the test. Each composition was tested in the bench-scale cone calorimeter (ISO 5660) and burnt as a whole sofa-bed in a sofa configuration in a 3.4 × 2.25 × 2.4 m 3 test room. All of the sofas were ignited with a No. 7 wood crib; the temperatures and yields of toxic products are reported. The sofa-beds containing flame retardants burnt somewhat more slowly than the non-flame retarded EU sofa-bed, but in doing so produced significantly greater quantities of the main fire toxicants, carbon monoxide and hydrogen cyanide. Assessment of the effluents' potential to incapacitate and kill is provided showing the two UK flame retardant sofa-beds to be the most dangerous, followed by the sofa-bed made with European materials. The UK sofa-bed made only from natural materials (Cottonsafe ® ) burnt very slowly and produced very low concentrations of toxic gases. Including fire toxicity in the FFR would reduce the chemical flame retardants and improve fire safety. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  8. Heat Release Rate of an Open Kitchen Fire of Small Residential Units in Tall Buildings

    OpenAIRE

    Chow, W.K.

    2014-01-01

    Many small units of area less than 30 m2 in residential buildings over 200 m tall are equipped with open kitchens in Asia, including Hong Kong. Fire safety provisions of these kitchens are determined by performance-based design (PBD). In most PBD projects, only the spread of smoke from the kitchen on fire to the outside was commonly studied. However, a fire load survey in Hong Kong indicated large quantities of combustibles are stored in residential units. Cooking oil was found to be ignited ...

  9. Effect of calorie restriction on spontaneous physical activity and body mass in mice divergently selected for basal metabolic rate (BMR).

    Science.gov (United States)

    Brzęk, Paweł; Gębczyński, Andrzej K; Książek, Aneta; Konarzewski, Marek

    2016-07-01

    Spontaneous physical activity (SPA) represents an important component of daily energy expenditures in animals and humans. Intra-specific variation in SPA may be related to the susceptibility to metabolic disease or obesity. In particular, reduced SPA under conditions of limited food availability may conserve energy and prevent loss of body and fat mass ('thrifty genotype hypothesis'). However, both SPA and its changes during food restriction show wide inter-individual variations. We studied the effect of 30% caloric restriction (CR) on SPA in laboratory mice divergently selected for high (H-BMR) and low (L-BMR) basal metabolic rate. Selection increased SPA in the H-BMR line but did not change it in the L-BMR mice. This effect reflected changes in SPA intensity but not SPA duration. CR increased SPA intensity more strongly in the L-BMR line than in the H-BMR line and significantly modified the temporal variation of SPA. However, the initial between-line differences in SPA were not affected by CR. Loss of body mass during CR did not differ between both lines. Our results show that the H-BMR mice can maintain their genetically determined high SPA under conditions of reduced food intake without sacrificing their body mass. We hypothesize that this pattern may reflect the higher flexibility in the energy budget in the H-BMR line, as we showed previously that mice from this line reduced their BMR during CR. These energy savings may allow for the maintenance of elevated SPA in spite of reduced food intake. We conclude that the effect of CR on SPA is in large part determined by the initial level of BMR, whose variation may account for the lack of universal pattern of behavioural responses to CR. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Inhibition of Inactive States of Tetrodotoxin-Sensitive Sodium Channels Reduces Spontaneous Firing of C-Fiber Nociceptors and Produces Analgesia in Formalin and Complete Freund's Adjuvant Models of Pain.

    Directory of Open Access Journals (Sweden)

    David J Matson

    Full Text Available While genetic evidence shows that the Nav1.7 voltage-gated sodium ion channel is a key regulator of pain, it is unclear exactly how Nav1.7 governs neuronal firing and what biophysical, physiological, and distribution properties of a pharmacological Nav1.7 inhibitor are required to produce analgesia. Here we characterize a series of aminotriazine inhibitors of Nav1.7 in vitro and in rodent models of pain and test the effects of the previously reported "compound 52" aminotriazine inhibitor on the spiking properties of nociceptors in vivo. Multiple aminotriazines, including some with low terminal brain to plasma concentration ratios, showed analgesic efficacy in the formalin model of pain. Effective concentrations were consistent with the in vitro potency as measured on partially-inactivated Nav1.7 but were far below concentrations required to inhibit non-inactivated Nav1.7. Compound 52 also reversed thermal hyperalgesia in the complete Freund's adjuvant (CFA model of pain. To study neuronal mechanisms, electrophysiological recordings were made in vivo from single nociceptive fibers from the rat tibial nerve one day after CFA injection. Compound 52 reduced the spontaneous firing of C-fiber nociceptors from approximately 0.7 Hz to 0.2 Hz and decreased the number of action potentials evoked by suprathreshold tactile and heat stimuli. It did not, however, appreciably alter the C-fiber thresholds for response to tactile or thermal stimuli. Surprisingly, compound 52 did not affect spontaneous activity or evoked responses of Aδ-fiber nociceptors. Results suggest that inhibition of inactivated states of TTX-S channels, mostly likely Nav1.7, in the peripheral nervous system produces analgesia by regulating the spontaneous discharge of C-fiber nociceptors.

  11. Motor unit recruitment and firing rate in medial gastrocnemius muscles during external perturbations in standing in humans.

    Science.gov (United States)

    Pollock, C L; Ivanova, T D; Hunt, M A; Garland, S J

    2014-10-01

    There is limited investigation of the interaction between motor unit recruitment and rate coding for modulating force during standing or responding to external perturbations. Fifty-seven motor units were recorded from the medial gastrocnemius muscle with intramuscular electrodes in response to external perturbations in standing. Anteriorly directed perturbations were generated by applying loads in 0.45-kg increments at the pelvis every 25-40 s until 2.25 kg was maintained. Motor unit firing rate was calculated for the initial recruitment load and all subsequent loads during two epochs: 1) dynamic response to perturbation directly following each load drop and 2) maintenance of steady state between perturbations. Joint kinematics and surface electromyography (EMG) from lower extremities and force platform measurements were assessed. Application of the external loads resulted in a significant forward progression of the anterior-posterior center of pressure (AP COP) that was accompanied by modest changes in joint angles (recruitment, motor unit firing rate immediately after the load drop was significantly lower than during subsequent load drops or during the steady state at the same load. There was a modest increase in motor unit firing rate immediately after the load drop on subsequent load drops associated with regaining balance. There was no effect of maintaining balance with increased load and forward progression of the AP COP on steady-state motor unit firing rate. The medial gastrocnemius utilized primarily motor unit recruitment to achieve the increased levels of activation necessary to maintain standing in the presence of external loads. Copyright © 2014 the American Physiological Society.

  12. Effect of low-intensity low-dose rate irradiation on the incidence and the development of spontaneous leukosis in AKR mice

    International Nuclear Information System (INIS)

    Burlakova, E.B.; Erokhin, V.N.

    2001-01-01

    Development of spontaneous leukosis in AKR mice is accelerated by irradiation with low doses of 1.2-2.4 cGy and low dose rate 0.06 cGy/day. The leukoses incidence rate increases. Deaths of the animals from leukosis occurs earlier, shortening the average and maximum life-spans of the animals. The dynamics of changes in the mass of organs of the immune systems (thymus and spleen) shows extrema. The moment of reaching the extremum correlates with the maximum rate of animals' deaths [ru

  13. Substance P Differentially Modulates Firing Rate of Solitary Complex (SC) Neurons from Control and Chronic Hypoxia-Adapted Adult Rats

    Science.gov (United States)

    Nichols, Nicole L.; Powell, Frank L.; Dean, Jay B.; Putnam, Robert W.

    2014-01-01

    NK1 receptors, which bind substance P, are present in the majority of brainstem regions that contain CO2/H+-sensitive neurons that play a role in central chemosensitivity. However, the effect of substance P on the chemosensitive response of neurons from these regions has not been studied. Hypoxia increases substance P release from peripheral afferents that terminate in the caudal nucleus tractus solitarius (NTS). Here we studied the effect of substance P on the chemosensitive responses of solitary complex (SC: NTS and dorsal motor nucleus) neurons from control and chronic hypoxia-adapted (CHx) adult rats. We simultaneously measured intracellular pH and electrical responses to hypercapnic acidosis in SC neurons from control and CHx adult rats using the blind whole cell patch clamp technique and fluorescence imaging microscopy. Substance P significantly increased the basal firing rate in SC neurons from control and CHx rats, although the increase was smaller in CHx rats. However, substance P did not affect the chemosensitive response of SC neurons from either group of rats. In conclusion, we found that substance P plays a role in modulating the basal firing rate of SC neurons but the magnitude of the effect is smaller for SC neurons from CHx adult rats, implying that NK1 receptors may be down regulated in CHx adult rats. Substance P does not appear to play a role in modulating the firing rate response to hypercapnic acidosis of SC neurons from either control or CHx adult rats. PMID:24516602

  14. Substance P differentially modulates firing rate of solitary complex (SC neurons from control and chronic hypoxia-adapted adult rats.

    Directory of Open Access Journals (Sweden)

    Nicole L Nichols

    Full Text Available NK1 receptors, which bind substance P, are present in the majority of brainstem regions that contain CO2/H(+-sensitive neurons that play a role in central chemosensitivity. However, the effect of substance P on the chemosensitive response of neurons from these regions has not been studied. Hypoxia increases substance P release from peripheral afferents that terminate in the caudal nucleus tractus solitarius (NTS. Here we studied the effect of substance P on the chemosensitive responses of solitary complex (SC: NTS and dorsal motor nucleus neurons from control and chronic hypoxia-adapted (CHx adult rats. We simultaneously measured intracellular pH and electrical responses to hypercapnic acidosis in SC neurons from control and CHx adult rats using the blind whole cell patch clamp technique and fluorescence imaging microscopy. Substance P significantly increased the basal firing rate in SC neurons from control and CHx rats, although the increase was smaller in CHx rats. However, substance P did not affect the chemosensitive response of SC neurons from either group of rats. In conclusion, we found that substance P plays a role in modulating the basal firing rate of SC neurons but the magnitude of the effect is smaller for SC neurons from CHx adult rats, implying that NK1 receptors may be down regulated in CHx adult rats. Substance P does not appear to play a role in modulating the firing rate response to hypercapnic acidosis of SC neurons from either control or CHx adult rats.

  15. Quasi-static method and finite element method for obtaining the modifications of the spontaneous emission rate and energy level shift near a plasmonic nanostructure.

    Science.gov (United States)

    Zhao, Yun-Jin; Tian, Meng; Wang, Xiao-Yun; Yang, Hong; Zhao, Heping; Huang, Yong-Gang

    2018-01-22

    We provide numerical demonstrations of the applicability and accuracy of the quasi-static method and the finite-element method in the investigation of the modifications of the spontaneous emission rate and the energy level shift of an emitter placed near a silver-air interface or a silver nano-sphere. The analytical results are presented as a reference. Our calculations show that the finite element method is an accurate and general method. For frequency away from the radiative mode, the quasi-static method can be applied more effectively for calculating the energy level shift than the spontaneous emission rate. But for frequency around, there is a blue shift for both and this shift increases with the increasing of emitter-silver distance. Applying the theory to the nanosphere dimmer, we see similar phenomenon and find extremely large modifications of the spontaneous emission rate and energy level shift. These findings are instructive in the fields of quantum light-matter interactions.

  16. Are High-Severity Fires Burning at Much Higher Rates Recently than Historically in Dry-Forest Landscapes of the Western USA?

    Science.gov (United States)

    Baker, William L

    2015-01-01

    Dry forests at low elevations in temperate-zone mountains are commonly hypothesized to be at risk of exceptional rates of severe fire from climatic change and land-use effects. Their setting is fire-prone, they have been altered by land-uses, and fire severity may be increasing. However, where fires were excluded, increased fire could also be hypothesized as restorative of historical fire. These competing hypotheses are not well tested, as reference data prior to widespread land-use expansion were insufficient. Moreover, fire-climate projections were lacking for these forests. Here, I used new reference data and records of high-severity fire from 1984-2012 across all dry forests (25.5 million ha) of the western USA to test these hypotheses. I also approximated projected effects of climatic change on high-severity fire in dry forests by applying existing projections. This analysis showed the rate of recent high-severity fire in dry forests is within the range of historical rates, or is too low, overall across dry forests and individually in 42 of 43 analysis regions. Significant upward trends were lacking overall from 1984-2012 for area burned and fraction burned at high severity. Upward trends in area burned at high severity were found in only 4 of 43 analysis regions. Projections for A.D. 2046-2065 showed high-severity fire would generally be still operating at, or have been restored to historical rates, although high projections suggest high-severity fire rotations that are too short could ensue in 6 of 43 regions. Programs to generally reduce fire severity in dry forests are not supported and have significant adverse ecological impacts, including reducing habitat for native species dependent on early-successional burned patches and decreasing landscape heterogeneity that confers resilience to climatic change. Some adverse ecological effects of high-severity fires are concerns. Managers and communities can improve our ability to live with high-severity fire in

  17. Effects of a hot-water extract of porcini (Boletus aestivalis) mushrooms on the blood pressure and heart rate of spontaneously hypertensive rats.

    Science.gov (United States)

    Midoh, Naoki; Miyazawa, Noriko; Eguchi, Fumio

    2013-01-01

    The repeated once-daily oral administration of a hot-water extract of porcini, Boletus aestivalis, mushrooms (WEP) to spontaneously hypertensive rats (SHR) for 18 weeks decreased the systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate. The WEP administration also decreased blood urea nitrogen (BUN), creatinine (Cre), and triglyceride (TG), and increased high-density lipoprotein-cholesterol (HDL-C) in the blood, suggesting that WEP improved the status of hypertension, as well as the high heart rate and metabolic abnormalities involved in hypertension.

  18. Quantifying emissions from spontaneous combustion

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-09-01

    Spontaneous combustion can be a significant problem in the coal industry, not only due to the obvious safety hazard and the potential loss of valuable assets, but also with respect to the release of gaseous pollutants, especially CO2, from uncontrolled coal fires. This report reviews methodologies for measuring emissions from spontaneous combustion and discusses methods for quantifying, estimating and accounting for the purpose of preparing emission inventories.

  19. Flow Friction or Spontaneous Ignition?

    Science.gov (United States)

    Stoltzfus, Joel M.; Gallus, Timothy D.; Sparks, Kyle

    2012-01-01

    "Flow friction," a proposed ignition mechanism in oxygen systems, has proved elusive in attempts at experimental verification. In this paper, the literature regarding flow friction is reviewed and the experimental verification attempts are briefly discussed. Another ignition mechanism, a form of spontaneous combustion, is proposed as an explanation for at least some of the fire events that have been attributed to flow friction in the literature. In addition, the results of a failure analysis performed at NASA Johnson Space Center White Sands Test Facility are presented, and the observations indicate that spontaneous combustion was the most likely cause of the fire in this 2000 psig (14 MPa) oxygen-enriched system.

  20. The synthetic cannabinoid HU210 induces spatial memory deficits and suppresses hippocampal firing rate in rats.

    Science.gov (United States)

    Robinson, L; Goonawardena, A V; Pertwee, R G; Hampson, R E; Riedel, G

    2007-07-01

    Previous work implied that the hippocampal cannabinoid system was particularly important in some forms of learning, but direct evidence for this hypothesis is scarce. We therefore assessed the effects of the synthetic cannabinoid HU210 on memory and hippocampal activity. HU210 (100 microg kg(-1)) was administered intraperitoneally to rats under three experimental conditions. One group of animals were pre-trained in spatial working memory using a delayed-matching-to-position task and effects of HU210 were assessed in a within-subject design. In another, rats were injected before acquisition learning of a spatial reference memory task with constant platform location. Finally, a separate group of animals was implanted with electrode bundles in CA1 and CA3 and single unit responses were isolated, before and after HU210 treatment. HU210 treatment had no effect on working or short-term memory. Relative to its control Tween 80, deficits in acquisition of a reference memory version of the water maze were obtained, along with drug-related effects on anxiety, motor activity and spatial learning. Deficits were not reversed by the CB(1) receptor antagonists SR141716A (3 mg kg(-1)) or AM281 (1.5 mg kg(-1)). Single unit recordings from principal neurons in hippocampal CA3 and CA1 confirmed HU210-induced attenuation of the overall firing activity lowering both the number of complex spikes fired and the occurrence of bursts. These data provide the first direct evidence that the underlying mechanism for the spatial memory deficits induced by HU210 in rats is the accompanying abnormality in hippocampal cell firing.

  1. A fast 30 kV 5 kHz repetition rate resonant capacitor charger

    NARCIS (Netherlands)

    Beckers, F.J.C.M.; Huiskamp, T.; van Heesch, E.J.M.; Pemen, A.J.M.

    2016-01-01

    A novel circuit topology of a fast 30 kV resonant capacitor charger is presented in this paper. The charger is designed for high repetition rate spark gap based pulsed power modulators. A spark gap can fire spontaneously (pre-firing) during charging of a capacitor bank due to poor dielectric

  2. Recent amendments of the KTA 2101.2 fire barrier resistance rating method for German NPP and comparison to the Eurocode t-equivalent method

    Energy Technology Data Exchange (ETDEWEB)

    Forell, Burkhard [Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) gGmbH, Koeln (Germany)

    2015-12-15

    The German nuclear standard KTA2101 on ''Fire Protection in Nuclear Power Plants'', Part 2: ''Fire Protection of Structural Plant Components'' includes a simplified method for the fire resistance rating of fire barrier elements based on the t-equivalent approach. The method covers the specific features of compartments in nuclear power plant buildings in terms of the boundary conditions which have to be expected in the event of fire. The method has proven to be relatively simple and straightforward to apply. The paper gives an overview of amendments with respect to the rating method made within the regular review of the KTA 2101.2. A comparison to the method of the non-nuclear Eurocode 1 is also provided. The Eurocode method is closely connected to the German standard DIN 18230 on structural fire protection in industrial buildings. Special emphasis of the comparison is given to the ventilation factor, which has a large impact on the required fire resistance.

  3. Spontaneous Unfolding-Refolding of Fibronectin Type III Domains Assayed by Thiol Exchange: THERMODYNAMIC STABILITY CORRELATES WITH RATES OF UNFOLDING RATHER THAN FOLDING.

    Science.gov (United States)

    Shah, Riddhi; Ohashi, Tomoo; Erickson, Harold P; Oas, Terrence G

    2017-01-20

    Globular proteins are not permanently folded but spontaneously unfold and refold on time scales that can span orders of magnitude for different proteins. A longstanding debate in the protein-folding field is whether unfolding rates or folding rates correlate to the stability of a protein. In the present study, we have determined the unfolding and folding kinetics of 10 FNIII domains. FNIII domains are one of the most common protein folds and are present in 2% of animal proteins. FNIII domains are ideal for this study because they have an identical seven-strand β-sandwich structure, but they vary widely in sequence and thermodynamic stability. We assayed thermodynamic stability of each domain by equilibrium denaturation in urea. We then assayed the kinetics of domain opening and closing by a technique known as thiol exchange. For this we introduced a buried Cys at the identical location in each FNIII domain and measured the kinetics of labeling with DTNB over a range of urea concentrations. A global fit of the kinetics data gave the kinetics of spontaneous unfolding and refolding in zero urea. We found that the folding rates were relatively similar, ∼0.1-1 s -1 , for the different domains. The unfolding rates varied widely and correlated with thermodynamic stability. Our study is the first to address this question using a set of domains that are structurally homologous but evolved with widely varying sequence identity and thermodynamic stability. These data add new evidence that thermodynamic stability correlates primarily with unfolding rate rather than folding rate. The study also has implications for the question of whether opening of FNIII domains contributes to the stretching of fibronectin matrix fibrils. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  4. Acute effects of dynamic exercises on the relationship between the motor unit firing rate and the recruitment threshold.

    Science.gov (United States)

    Ye, Xin; Beck, Travis W; DeFreitas, Jason M; Wages, Nathan P

    2015-04-01

    The aim of this study was to compare the acute effects of concentric versus eccentric exercise on motor control strategies. Fifteen men performed six sets of 10 repetitions of maximal concentric exercises or eccentric isokinetic exercises with their dominant elbow flexors on separate experimental visits. Before and after the exercise, maximal strength testing and submaximal trapezoid isometric contractions (40% of the maximal force) were performed. Both exercise conditions caused significant strength loss in the elbow flexors, but the loss was greater following the eccentric exercise (t=2.401, P=.031). The surface electromyographic signals obtained from the submaximal trapezoid isometric contractions were decomposed into individual motor unit action potential trains. For each submaximal trapezoid isometric contraction, the relationship between the average motor unit firing rate and the recruitment threshold was examined using linear regression analysis. In contrast to the concentric exercise, which did not cause significant changes in the mean linear slope coefficient and y-intercept of the linear regression line, the eccentric exercise resulted in a lower mean linear slope and an increased mean y-intercept, thereby indicating that increasing the firing rates of low-threshold motor units may be more important than recruiting high-threshold motor units to compensate for eccentric exercise-induced strength loss. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. An evaluation of fresh gas flow rates for spontaneously breathing cats and small dogs on the Humphrey ADE semi-closed breathing system.

    Science.gov (United States)

    Gale, Elizabeth; Ticehurst, Kim E; Zaki, Sanaa

    2015-05-01

    To evaluate the fresh gas flow (FGF) rate requirements for the Humphrey ADE semi-closed breathing system in the Mapleson A mode; to determine the FGF at which rebreathing occurs, and compare the efficiency of this system to the Bain (Mapleson D) system in spontaneously breathing cats and small dogs. Prospective clinical study. Twenty-five healthy (ASA score I or II) client-owned cats and dogs (mean ± SD age 4.7 ± 5.0 years, and body weight 5.64 ± 3.26 kg) undergoing elective surgery or minor procedures. Anaesthesia was maintained with isoflurane delivered via the Humphrey ADE system in the A mode using an oxygen FGF of 100 mL kg(-1) minute(-1). The FGF was then reduced incrementally by 5-10 mL kg(-1) minute(-1) at approximately five-minute intervals, until rebreathing (inspired CO(2) >5 mmHg (0.7 kPa)) was observed, after which flow rates were increased. In six animals, once the minimum FGF at which rebreathing occurred was found, the breathing system was changed to the Bain, and the effects of this FGF delivery examined, before FGF was increased. Rebreathing did not occur at the FGF recommended by the manufacturer for the ADE. The mean ± SD FGF that resulted in rebreathing was 60 ± 20 mL kg(-1) minute(-1). The mean minimum FGF at which rebreathing did not occur with the ADE was 87 ± 39 mL kg(-1) minute(-1). This FGF resulted in significant rebreathing (inspired CO(2) 8.8 ± 2.6 mmHg (1.2 ± 0.3 kPa)) on the Bain system. The FGF rates recommended for the Humphrey ADE are adequate to prevent rebreathing in spontaneously breathing cats and dogs cats and small dogs. © 2014 Association of Veterinary Anaesthetists and the American College of Veterinary Anesthesia and Analgesia.

  6. The effects of prostaglandin E2 on the firing rate activity of thermosensitive and temperature insensitive neurons in the ventromedial preoptic area of the rat hypothalamus.

    Science.gov (United States)

    Ranels, Heather J; Griffin, John D

    2003-02-21

    In response to an immune system challenge with lipopolysaccharide (LPS), recent work has shown that Fos immunoreactivity is displayed by neurons in the ventromedial preoptic area of the hypothalamus (VMPO). In addition, neurons in this region show distinct axonal projections to the anterior perifornical area (APFx) and the paraventricular nucleus (PVN). It has been hypothesized that neurons within the VMPO integrate their local responses to temperature with changes in firing activity that result from LPS induced production of prostaglandin E(2) (PGE(2)). This may be an important mechanism by which the set-point regulation of thermoeffector neurons in the APFx and PVN is altered, resulting in hyperthermia. To characterize the firing rate activity of VMPO neurons, single-unit recordings were made of neuronal extracellular activity in rat hypothalamic tissue slices. Based on the slope of firing rate as a function of tissue temperature, neurons were classified as either warm sensitive or temperature insensitive. Neurons were then treated with PGE(2) (200 nM) while tissue temperature was held at a constant level ( approximately 36 degrees C). The majority of temperature insensitive neurons responded to PGE(2) with an increase in firing rate activity, while warm sensitive neurons showed a reduction in firing rate. This suggests that both warm sensitive and temperature insensitive neurons in the VMPO may play critical and contrasting roles in the production of a fever during an acute phase response to infection.

  7. Localized states in an unbounded neural field equation with smooth firing rate function: a multi-parameter analysis.

    Science.gov (United States)

    Faye, Grégory; Rankin, James; Chossat, Pascal

    2013-05-01

    The existence of spatially localized solutions in neural networks is an important topic in neuroscience as these solutions are considered to characterize working (short-term) memory. We work with an unbounded neural network represented by the neural field equation with smooth firing rate function and a wizard hat spatial connectivity. Noting that stationary solutions of our neural field equation are equivalent to homoclinic orbits in a related fourth order ordinary differential equation, we apply normal form theory for a reversible Hopf bifurcation to prove the existence of localized solutions; further, we present results concerning their stability. Numerical continuation is used to compute branches of localized solution that exhibit snaking-type behaviour. We describe in terms of three parameters the exact regions for which localized solutions persist.

  8. The Rate and Spectrum of Spontaneous Mutations in Mycobacterium smegmatis, a Bacterium Naturally Devoid of the Postreplicative Mismatch Repair Pathway.

    Science.gov (United States)

    Kucukyildirim, Sibel; Long, Hongan; Sung, Way; Miller, Samuel F; Doak, Thomas G; Lynch, Michael

    2016-07-07

    Mycobacterium smegmatis is a bacterium that is naturally devoid of known postreplicative DNA mismatch repair (MMR) homologs, mutS and mutL, providing an opportunity to investigate how the mutation rate and spectrum has evolved in the absence of a highly conserved primary repair pathway. Mutation accumulation experiments of M. smegmatis yielded a base-substitution mutation rate of 5.27 × 10(-10) per site per generation, or 0.0036 per genome per generation, which is surprisingly similar to the mutation rate in MMR-functional unicellular organisms. Transitions were found more frequently than transversions, with the A:T→G:C transition rate significantly higher than the G:C→A:T transition rate, opposite to what is observed in most studied bacteria. We also found that the transition-mutation rate of M. smegmatis is significantly lower than that of other naturally MMR-devoid or MMR-knockout organisms. Two possible candidates that could be responsible for maintaining high DNA fidelity in this MMR-deficient organism are the ancestral-like DNA polymerase DnaE1, which contains a highly efficient DNA proofreading histidinol phosphatase (PHP) domain, and/or the existence of a uracil-DNA glycosylase B (UdgB) homolog that might protect the GC-rich M. smegmatis genome against DNA damage arising from oxidation or deamination. Our results suggest that M. smegmatis has a noncanonical Dam (DNA adenine methylase) methylation system, with target motifs differing from those previously reported. The mutation features of M. smegmatis provide further evidence that genomes harbor alternative routes for improving replication fidelity, even in the absence of major repair pathways. Copyright © 2016 Kucukyildirim et al.

  9. The Rate and Spectrum of Spontaneous Mutations in Mycobacterium smegmatis, a Bacterium Naturally Devoid of the Postreplicative Mismatch Repair Pathway

    Directory of Open Access Journals (Sweden)

    Sibel Kucukyildirim

    2016-07-01

    Full Text Available Mycobacterium smegmatis is a bacterium that is naturally devoid of known postreplicative DNA mismatch repair (MMR homologs, mutS and mutL, providing an opportunity to investigate how the mutation rate and spectrum has evolved in the absence of a highly conserved primary repair pathway. Mutation accumulation experiments of M. smegmatis yielded a base-substitution mutation rate of 5.27 × 10−10 per site per generation, or 0.0036 per genome per generation, which is surprisingly similar to the mutation rate in MMR-functional unicellular organisms. Transitions were found more frequently than transversions, with the A:T→G:C transition rate significantly higher than the G:C→A:T transition rate, opposite to what is observed in most studied bacteria. We also found that the transition-mutation rate of M. smegmatis is significantly lower than that of other naturally MMR-devoid or MMR-knockout organisms. Two possible candidates that could be responsible for maintaining high DNA fidelity in this MMR-deficient organism are the ancestral-like DNA polymerase DnaE1, which contains a highly efficient DNA proofreading histidinol phosphatase (PHP domain, and/or the existence of a uracil-DNA glycosylase B (UdgB homolog that might protect the GC-rich M. smegmatis genome against DNA damage arising from oxidation or deamination. Our results suggest that M. smegmatis has a noncanonical Dam (DNA adenine methylase methylation system, with target motifs differing from those previously reported. The mutation features of M. smegmatis provide further evidence that genomes harbor alternative routes for improving replication fidelity, even in the absence of major repair pathways.

  10. Glucagon-like peptide-1 acutely affects renal blood flow and urinary flow rate in spontaneously hypertensive rats despite significantly reduced renal expression of GLP-1 receptors

    DEFF Research Database (Denmark)

    Ronn, Jonas; Jensen, Elisa P; Wewer Albrechtsen, Nicolai J

    2017-01-01

    to increased mean arterial pressure (MAP) and increased renal blood flow (RBF). In hypertensive animal models, GLP-1 has been reported both to increase and decrease MAP. The aim of this study was to examine expression of renal GLP-1 receptors in spontaneously hypertensive rats (SHR) and to assess the effect......Glucagon-like peptide-1 (GLP-1) is an incretin hormone increasing postprandial insulin release. GLP-1 also induces diuresis and natriuresis in humans and rodents. The GLP-1 receptor is extensively expressed in the renal vascular tree in normotensive rats where acute GLP-1 treatment leads...... in the kidney from SHR. However, acute intrarenal infusion of GLP-1 increased MAP, RBF, dieresis, and natriuresis without affecting heart rate in both rat strains. These results suggest that the acute renal effects of GLP-1 in SHR are caused either by extrarenal GLP-1 receptors activating other mechanisms (e...

  11. Evidence of circadian rhythm, oxygen regulation capacity, metabolic repeatability and positive correlations between forced and spontaneous maximal metabolic rates in lake sturgeon Acipenser fulvescens.

    Directory of Open Access Journals (Sweden)

    Jon C Svendsen

    Full Text Available Animal metabolic rate is variable and may be affected by endogenous and exogenous factors, but such relationships remain poorly understood in many primitive fishes, including members of the family Acipenseridae (sturgeons. Using juvenile lake sturgeon (Acipenser fulvescens, the objective of this study was to test four hypotheses: 1 A. fulvescens exhibits a circadian rhythm influencing metabolic rate and behaviour; 2 A. fulvescens has the capacity to regulate metabolic rate when exposed to environmental hypoxia; 3 measurements of forced maximum metabolic rate (MMR(F are repeatable in individual fish; and 4 MMR(F correlates positively with spontaneous maximum metabolic rate (MMR(S. Metabolic rates were measured using intermittent flow respirometry, and a standard chase protocol was employed to elicit MMR(F. Trials lasting 24 h were used to measure standard metabolic rate (SMR and MMR(S. Repeatability and correlations between MMR(F and MMR(S were analyzed using residual body mass corrected values. Results revealed that A. fulvescens exhibit a circadian rhythm in metabolic rate, with metabolism peaking at dawn. SMR was unaffected by hypoxia (30% air saturation (O(2sat, demonstrating oxygen regulation. In contrast, MMR(F was affected by hypoxia and decreased across the range from 100% O(2sat to 70% O(2sat. MMR(F was repeatable in individual fish, and MMR(F correlated positively with MMR(S, but the relationships between MMR(F and MMR(S were only revealed in fish exposed to hypoxia or 24 h constant light (i.e. environmental stressor. Our study provides evidence that the physiology of A. fulvescens is influenced by a circadian rhythm and suggests that A. fulvescens is an oxygen regulator, like most teleost fish. Finally, metabolic repeatability and positive correlations between MMR(F and MMR(S support the conjecture that MMR(F represents a measure of organism performance that could be a target of natural selection.

  12. The potential predictability of fire danger provided by ECMWF forecast

    Science.gov (United States)

    Di Giuseppe, Francesca

    2017-04-01

    The European Forest Fire Information System (EFFIS), is currently being developed in the framework of the Copernicus Emergency Management Services to monitor and forecast fire danger in Europe. The system provides timely information to civil protection authorities in 38 nations across Europe and mostly concentrates on flagging regions which might be at high danger of spontaneous ignition due to persistent drought. The daily predictions of fire danger conditions are based on the US Forest Service National Fire Danger Rating System (NFDRS), the Canadian forest service Fire Weather Index Rating System (FWI) and the Australian McArthur (MARK-5) rating systems. Weather forcings are provided in real time by the European Centre for Medium range Weather Forecasts (ECMWF) forecasting system. The global system's potential predictability is assessed using re-analysis fields as weather forcings. The Global Fire Emissions Database (GFED4) provides 11 years of observed burned areas from satellite measurements and is used as a validation dataset. The fire indices implemented are good predictors to highlight dangerous conditions. High values are correlated with observed fire and low values correspond to non observed events. A more quantitative skill evaluation was performed using the Extremal Dependency Index which is a skill score specifically designed for rare events. It revealed that the three indices were more skilful on a global scale than the random forecast to detect large fires. The performance peaks in the boreal forests, in the Mediterranean, the Amazon rain-forests and southeast Asia. The skill-scores were then aggregated at country level to reveal which nations could potentiallty benefit from the system information in aid of decision making and fire control support. Overall we found that fire danger modelling based on weather forecasts, can provide reasonable predictability over large parts of the global landmass.

  13. Fuel treatment effectiveness in reducing fire intensity and spread rate - An experimental overview

    Science.gov (United States)

    Eric Mueller; Nicholas Skowronski; Albert Simeoni; Kenneth Clark; Robert Kremens; William Mell; Michael Gallagher; Jan Thomas; Alexander Filkov; Mohamad El Houssami; John Hom; Bret Butler

    2014-01-01

    Fuel treatments represent a significant component of the wildfire mitigation strategy in the United States. However, the lack of research aimed at quantifying the explicit effectiveness of fuel treatments in reducing wildfire intensity and spread rate limits our ability to make educated decisions about the type and placement of these treatments. As part of a larger...

  14. Noise exposure alters long-term neural firing rates and synchrony in primary auditory and rostral belt cortices following bimodal stimulation.

    Science.gov (United States)

    Takacs, Joseph D; Forrest, Taylor J; Basura, Gregory J

    2017-12-01

    We previously demonstrated that bimodal stimulation (spinal trigeminal nucleus [Sp5] paired with best frequency tone) altered neural tone-evoked and spontaneous firing rates (SFRs) in primary auditory cortex (A1) 15 min after pairing in guinea pigs with and without noise-induced tinnitus. Neural responses were enhanced (+10 ms) or suppressed (0 ms) based on the bimodal pairing interval. Here we investigated whether bimodal stimulation leads to long-term (up to 2 h) changes in tone-evoked and SFRs and neural synchrony (correlate of tinnitus) and if the long-term bimodal effects are altered following noise exposure. To obviate the effects of permanent hearing loss on the results, firing rates and neural synchrony were measured three weeks following unilateral (left ear) noise exposure and a temporary threshold shift. Simultaneous extra-cellular single-unit recordings were made from contralateral (to noise) A1 and dorsal rostral belt (RB); an associative auditory cortical region thought to influence A1, before and after bimodal stimulation (pairing intervals of 0 ms; simultaneous Sp5-tone and +10 ms; Sp5 precedes tone). Sixty and 120 min after 0 ms pairing tone-evoked and SFRs were suppressed in sham A1; an effect only preserved 120 min following pairing in noise. Stimulation at +10 ms only affected SFRs 120 min after pairing in sham and noise-exposed A1. Within sham RB, pairing at 0 and +10 ms persistently suppressed tone-evoked and SFRs, while 0 ms pairing in noise markedly enhanced tone-evoked and SFRs up to 2 h. Together, these findings suggest that bimodal stimulation has long-lasting effects in A1 that also extend to the associative RB that is altered by noise and may have persistent implications for how noise damaged brains process multi-sensory information. Moreover, prior to bimodal stimulation, noise damage increased neural synchrony in A1, RB and between A1 and RB neurons. Bimodal stimulation led to persistent changes in neural synchrony in

  15. A prolongation of the postspike afterhyperpolarization following spike trains can partly explain the lower firing rates at derecruitment than those at recruitment

    DEFF Research Database (Denmark)

    Wienecke, Jacob; Zhang, Mengliang; Hultborn, Hans

    2009-01-01

    rates at derecruitment correlated with a change in the postspike afterhyperpolarization (AHP) after preceding spike trains? This question was investigated by intracellular recordings from cat motor neurons in both unanesthetized and anesthetized preparations. The firing frequencies at recruitment...... for the lower frequencies at derecruitment. This was independent of whether the current injection had activated persistent inward current (PIC; plateau potentials, secondary range firing). It was found that a preceding spike train could prolong the AHP duration following a subsequent spike. The lower rate...... from AHP duration in fast motoneurons and higher than expected in slow motoneurons. It is suggested that these deviations are explained by the presence of synaptic noise as well as recruitment of PICs below firing threshold. Thus synaptic noise may allow spike discharge even after the end of the AHP...

  16. Spontaneous deregulation

    NARCIS (Netherlands)

    Edelman, Benjamin; Geradin, Damien

    Platform businesses such as Airbnb and Uber have risen to success partly by sidestepping laws and regulations that encumber their traditional competitors. Such rule flouting is what the authors call “spontaneous private deregulation,” and it’s happening in a growing number of industries. The authors

  17. The success rate of bupivacaine and lidocaine as anesthetic agents in inferior alveolar nerve block in teeth with irreversible pulpitis without spontaneous pain

    Directory of Open Access Journals (Sweden)

    Masoud Parirokh

    2015-05-01

    Full Text Available Objectives Achieving adequate anesthesia with inferior alveolar nerve blocks (IANB is of great importance during dental procedures. The aim of the present study was to assess the success rate of two anesthetic agents (bupivacaine and lidocaine for IANB when treating teeth with irreversible pulpitis. Materials and Methods Sixty volunteer male and female patients who required root canal treatment of a mandibular molar due to caries participated in the present study. The inclusion criteria included prolonged pain to thermal stimulus but no spontaneous pain. The patients were randomly allocated to receive either 2% lidocaine with 1:80,000 epinephrine or 0.5% bupivacaine with 1:200,000 epinephrine as an IANB injection. The sensitivity of the teeth to a cold test as well as the amount of pain during access cavity preparation and root canal instrumentation were recorded. Results were statistically analyzed with the Chi-Square and Fischer's exact tests. Results At the final step, fifty-nine patients were included in the study. The success rate for bupivacaine and lidocaine groups were 20.0% and 24.1%, respectively. There was no significant difference between the two groups at any stage of the treatment procedure. Conclusions There was no difference in success rates of anesthesia when bupivacaine and lidocaine were used for IANB injections to treat mandibular molar teeth with irreversible pulpitis. Neither agent was able to completely anesthetize the teeth effectively. Therefore, practitioners should be prepared to administer supplemental anesthesia to overcome pain during root canal treatment.

  18. The success rate of bupivacaine and lidocaine as anesthetic agents in inferior alveolar nerve block in teeth with irreversible pulpitis without spontaneous pain

    Science.gov (United States)

    Yosefi, Mohammad Hosein; Nakhaee, Nouzar

    2015-01-01

    Objectives Achieving adequate anesthesia with inferior alveolar nerve blocks (IANB) is of great importance during dental procedures. The aim of the present study was to assess the success rate of two anesthetic agents (bupivacaine and lidocaine) for IANB when treating teeth with irreversible pulpitis. Materials and Methods Sixty volunteer male and female patients who required root canal treatment of a mandibular molar due to caries participated in the present study. The inclusion criteria included prolonged pain to thermal stimulus but no spontaneous pain. The patients were randomly allocated to receive either 2% lidocaine with 1:80,000 epinephrine or 0.5% bupivacaine with 1:200,000 epinephrine as an IANB injection. The sensitivity of the teeth to a cold test as well as the amount of pain during access cavity preparation and root canal instrumentation were recorded. Results were statistically analyzed with the Chi-Square and Fischer's exact tests. Results At the final step, fifty-nine patients were included in the study. The success rate for bupivacaine and lidocaine groups were 20.0% and 24.1%, respectively. There was no significant difference between the two groups at any stage of the treatment procedure. Conclusions There was no difference in success rates of anesthesia when bupivacaine and lidocaine were used for IANB injections to treat mandibular molar teeth with irreversible pulpitis. Neither agent was able to completely anesthetize the teeth effectively. Therefore, practitioners should be prepared to administer supplemental anesthesia to overcome pain during root canal treatment. PMID:25984478

  19. The success rate of bupivacaine and lidocaine as anesthetic agents in inferior alveolar nerve block in teeth with irreversible pulpitis without spontaneous pain.

    Science.gov (United States)

    Parirokh, Masoud; Yosefi, Mohammad Hosein; Nakhaee, Nouzar; Abbott, Paul V; Manochehrifar, Hamed

    2015-05-01

    Achieving adequate anesthesia with inferior alveolar nerve blocks (IANB) is of great importance during dental procedures. The aim of the present study was to assess the success rate of two anesthetic agents (bupivacaine and lidocaine) for IANB when treating teeth with irreversible pulpitis. Sixty volunteer male and female patients who required root canal treatment of a mandibular molar due to caries participated in the present study. The inclusion criteria included prolonged pain to thermal stimulus but no spontaneous pain. The patients were randomly allocated to receive either 2% lidocaine with 1:80,000 epinephrine or 0.5% bupivacaine with 1:200,000 epinephrine as an IANB injection. The sensitivity of the teeth to a cold test as well as the amount of pain during access cavity preparation and root canal instrumentation were recorded. Results were statistically analyzed with the Chi-Square and Fischer's exact tests. At the final step, fifty-nine patients were included in the study. The success rate for bupivacaine and lidocaine groups were 20.0% and 24.1%, respectively. There was no significant difference between the two groups at any stage of the treatment procedure. There was no difference in success rates of anesthesia when bupivacaine and lidocaine were used for IANB injections to treat mandibular molar teeth with irreversible pulpitis. Neither agent was able to completely anesthetize the teeth effectively. Therefore, practitioners should be prepared to administer supplemental anesthesia to overcome pain during root canal treatment.

  20. Success and spontaneous pregnancy rates following systemic methotrexate versus laparoscopic surgery for tubal pregnancies: A randomized trial

    DEFF Research Database (Denmark)

    Krag Moeller, Lars Bo; Moeller, Charlotte; Thomsen, Sten Grove

    2009-01-01

    . A total of 106 women diagnosed with ectopic pregnancy (EP). Methods. Between March 1997 and September 2000, 1,265 women were diagnosed with EP, 395 (31%) were eligible, 109 (9%) were randomized of whom 106 had an EP. The study was originally powered to a sample size of 422 patients. The women were......Objective. To determine which treatment should be offered to women with a non-ruptured tubal pregnancy: a single dose of methotrexate (MTX) or laparoscopic surgery. Design. Prospective, randomized, open multicenter study. Setting. Seven Danish departments of obstetrics and gynecology. Sample...... (n.s.). Conclusions. In women with an EP, who are hemodynamically stable and wishing to preserve their fertility, medical treatment with single dose MTX tends to be equal to treatment with laparoscopic surgery regarding success rate, complications, and subsequent fertility. Although the two treatment...

  1. Stochastic representation of fire behavior in a wildland fire protection planning model for California.

    Science.gov (United States)

    J. Keith Gilless; Jeremy S. Fried

    1998-01-01

    A fire behavior module was developed for the California Fire Economics Simulator version 2 (CFES2), a stochastic simulation model of initial attack on wildland fire used by the California Department of Forestry and Fire Protection. Fire rate of spread (ROS) and fire dispatch level (FDL) for simulated fires "occurring" on the same day are determined by making...

  2. The correlation between burn mortality rates from fire and flame and economic status of countries.

    Science.gov (United States)

    Peck, Michael; Pressman, Melissa A

    2013-09-01

    Over 95% of burn deaths occur in low- and middle-income countries globally. However, the association between burn mortality rates and economic health has not been evaluated for individual countries. This study seeks to answer the question, how strong is the correlation between burn mortality and national indices of economic strength? A retrospective review was performed for 189 countries during 2008-2010 using economic data from the World Bank as well as mortality data from the World Health Organization (WHO). Countries were categorized into four groups based on income level according to stratification by the World Bank: low income, lower middle income, upper middle income, and high income. The Pearson correlation coefficient was used to estimate presence and strength of association among death rates, Gini coefficient (measure of inequality of distribution of wealth), gross domestic product (GDP) per capita, and gross national index (GNI) per capita. Statistically significant associations (p<0.05) were found between burn mortality and GDP per capita (r=-0.26), GNI per capita (r=-0.36), and Gini (r=+0.17). A nation's income level is negatively correlated with burn mortality; the lower the income level, the higher the burn mortality rates. The degree to which income within a country is equitably or inequitably distributed also correlates with burn mortality. Both governmental and non-governmental organizations need to focus on preventing burns in low-income countries, as well as in other countries in which there is marked disparity of income. Copyright © 2013 Elsevier Ltd and ISBI. All rights reserved.

  3. Effects of Tail Clipping on Larval Performance and Tail Regeneration Rates in the Near Eastern Fire Salamander, Salamandra infraimmaculata.

    Directory of Open Access Journals (Sweden)

    Ori Segev

    Full Text Available Tail-tip clipping is a common technique for collecting tissue samples from amphibian larvae and adults. Surprisingly, studies of this invasive sampling procedure or of natural tail clipping--i.e., bites inflicted by predators including conspecifics--on the performance and fitness of aquatic larval stages of urodeles are scarce. We conducted two studies in which we assessed the effects of posterior tail clipping (~30 percent of tail on Near Eastern fire salamander (Salamandra infraimmaculata larvae. In a laboratory study, we checked regeneration rates of posterior tail-tip clipping at different ages. Regeneration rates were hump-shaped, peaking at the age of ~30 days and then decreasing. This variation in tail regeneration rates suggests tradeoffs in resource allocation between regeneration and somatic growth during early and advanced development. In an outdoor artificial pond experiment, under constant larval densities, we assessed how tail clipping of newborn larvae affects survival to, time to, and size at metamorphosis. Repeated measures ANOVA on mean larval survival per pond revealed no effect of tail clipping. Tail clipping had correspondingly no effect on larval growth and development expressed in size (mass and snout-vent length at, and time to, metamorphosis. We conclude that despite the given variation in tail regeneration rates throughout larval ontogeny, clipping of 30% percent of the posterior tail area seems to have no adverse effects on larval fitness and survival. We suggest that future use of this imperative tool for the study of amphibian should take into account larval developmental stage during the time of application and not just the relative size of the clipped tail sample.

  4. Voluntary drive-dependent changes in vastus lateralis motor unit firing rates during a sustained isometric contraction at 50% of maximum knee extension force.

    NARCIS (Netherlands)

    de Ruiter, C.J.; Elzinga, M.J.; Verdijk, PW; van Mechelen, W.; de Haan, A.

    2004-01-01

    The purpose of the present study was to relate the expected inter-subject variability in voluntary drive of the knee extensor muscles during a sustained isometric contraction to the changes in firing rates of single motor units. Voluntary activation, as established with super-imposed electrical

  5. Furnace testing of electrical and pipe-penetration seals based on foamed silicone elastomer: 60, 90, and 120-minute fire ratings

    International Nuclear Information System (INIS)

    Brown, A.

    1979-03-01

    Fire tests of foamed silicone seals for electrical and pipe penetrations have been performed using a furnace with temperature control as heat source. The tests were performed in principle in accordance with the requirements of NORDTEST 5A (ISO 834). The purpose of the tests was to obtain appropriate fire ratings for different seal thicknesses. The report covers. - Description of material used to prepare the seals and method of application - Description of furnace test assembly and method of performing test - Listing of penetrating elements and of the thermocouple array used to measure temperature - Curves of thermocouple readouts and photographs of seals during and after completion of the test. (author)

  6. High temperature corrosion in straw-fired power plants: Influence of steam/metal temperature on corrosion rates for TP347H

    DEFF Research Database (Denmark)

    Montgomery, Melanie; Biede, O; Larsen, OH

    2002-01-01

    The corrosion in straw-fired boilers has been investigated at various straw-fired power plants in Denmark. Water/air-cooled probes, a test superheater and test sections removed from the actual superheater have been utilised to characterise corrosion and corrosion rates. This paper describes...... the corrosion rates measured for the TP347H type steel. The corrosion morphology at high temperature consists of grain boundary attack and selective attack of chromium. The corrosion rate increases with calculated metal temperature (based on steam temperature), however there is great variation within....... The difference in the results could be traced back to a lower flue gas temperature on one side of the boiler. Although metal temperature is the most important parameter with respect to corrosion rate, flue gas temperature also plays an important role. Efforts to quantify the effect of flue gas temperature...

  7. Multifaceted effects of oligodendroglial exosomes on neurons: impact on neuronal firing rate, signal transduction and gene regulation.

    Science.gov (United States)

    Fröhlich, Dominik; Kuo, Wen Ping; Frühbeis, Carsten; Sun, Jyh-Jang; Zehendner, Christoph M; Luhmann, Heiko J; Pinto, Sheena; Toedling, Joern; Trotter, Jacqueline; Krämer-Albers, Eva-Maria

    2014-09-26

    Exosomes are small membranous vesicles of endocytic origin that are released by almost every cell type. They exert versatile functions in intercellular communication important for many physiological and pathological processes. Recently, exosomes attracted interest with regard to their role in cell-cell communication in the nervous system. We have shown that exosomes released from oligodendrocytes upon stimulation with the neurotransmitter glutamate are internalized by neurons and enhance the neuronal stress tolerance. Here, we demonstrate that oligodendroglial exosomes also promote neuronal survival during oxygen-glucose deprivation, a model of cerebral ischaemia. We show the transfer from oligodendrocytes to neurons of superoxide dismutase and catalase, enzymes which are known to help cells to resist oxidative stress. Additionally, we identify various effects of oligodendroglial exosomes on neuronal physiology. Electrophysiological analysis using in vitro multi-electrode arrays revealed an increased firing rate of neurons exposed to oligodendroglial exosomes. Moreover, gene expression analysis and phosphorylation arrays uncovered differentially expressed genes and altered signal transduction pathways in neurons after exosome treatment. Our study thus provides new insight into the broad spectrum of action of oligodendroglial exosomes and their effects on neuronal physiology. The exchange of extracellular vesicles between neural cells may exhibit remarkable potential to impact brain performance. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  8. Spontaneous Pneumothorax

    Directory of Open Access Journals (Sweden)

    John Costumbrado

    2017-09-01

    Full Text Available History of present illness: A 16-year-old male with asthma was brought to the emergency department by his parents for increasing right-sided chest pain associated with cough and mild dyspnea over the past week. Albuterol inhaler did not provide relief. He denied recent trauma, fever, sweats, and chills. The patient’s vitals and oxygen saturations were stable. Physical exam revealed a tall, slender body habitus with no signs of chest wall injuries. Bilateral breath sounds were present, but slightly diminished on the right. A chest radiograph was ordered to determine the etiology of the patient’s symptoms. Significant findings: Initial chest radiograph showed a 50% right-sided pneumothorax with no mediastinal shift, which can be identified by the sharp line representing the pleural lung edge (see arrows and lack of peripheral lung markings extending to the chest wall. While difficult to accurately estimate volume from a two-dimensional image, a 2 cm pneumothorax seen on chest radiograph correlates to approximately 50% volume.1 The patient underwent insertion of a pigtail pleural drain on the right and repeat chest radiograph showed resolution of previously seen pneumothorax. Ultimately the pigtail drain was removed and chest radiograph showed clear lung fields without evidence of residual pneumothorax or pleural effusion. Discussion: Pneumothorax is characterized by air between the lungs and the chest wall.2 Spontaneous pneumothorax (SP occurs when the pneumothorax is not due to trauma or any discernable etiology. 3 SP is multifactorial and may be associated with subpleural blebs, bullae, and other connective tissue changes that predispose the lungs to leak air into the pleural space.4 SP can be further subdivided into primary (no history of underlying lung disease or secondary (history of chronic obstructive pulmonary disease, tuberculosis, cystic fibrosis, lung malignancy, etc..2 It is estimated that the incidence of SP among US pediatric

  9. Fire Models and Design Fires

    DEFF Research Database (Denmark)

    Poulsen, Annemarie

    The aim of this project is to perform an experimental study on the influence of the thermal feedback on the burning behavior of well ventilated pre-flashover fires. For the purpose an experimental method has been developed. Here the same identical objects are tested under free burn conditions...... carried out by Carleton University and NRC-IRC performed on seven different types of fire loads representing commercial premises, comprise the tests used for the study. The results show that for some of the room test the heat release rate increased due to thermal feedback compared to free burn for a pre......-flashover fire. Two phenomena were observed, that relate well to theory was found. In an incipient phase the heat release rate rose with the temperature of the smoke layer/enclosure boundaries. This increase was also found to depend on the flammability properties of the burning object. The results also...

  10. Emission Rate of Particulate Matter and Its Removal Efficiency by Precipitators in Under-Fired Charbroiling Restaurants

    Directory of Open Access Journals (Sweden)

    Jun-Bok Lee

    2011-01-01

    Full Text Available In order to explore the potent role of meat cooking processes as the emission sources of particulate matter (PM, emission rates and the associated removal efficiency by precipitators were estimated based on the on-site measurements made at five under-fired charbroiling (UFC restaurants. The emission patterns of PM for these five restaurants were compared after having been sorted into the main meat types used for cooking: beef (B, chicken (C, intestines (I, and pork (P: two sites. The mass concentrations (μg m-3 of three PM fractions (PM2.5/PM10/TSP measured from these restaurants were 15,510/15,701/17,175 (C; 8,525/10,760/12,676 (B; 11,027/13,249/13,488 (P; and 22,409/22,412/22,414 (I. Emission factors (g kg-1 for those PM fractions were also estimated as 3.23/4.08/4.80 (B, 3.07/3.82/3.87 (P, 8.12/8.22/8.99 (C, and 6.59/6.59/6.59 (I. If the annual emission rate of PM10 is extrapolated by combining its emission factor, population, activity factor, etc., it is estimated as 500 ton year-1, which corresponds to 2.4% of the PM10 budget in Seoul, Korea. Removal efficiencies of PM10 via precipitators, such as an electrostatic precipitator (ESP, bag filter (BF, and the combination system (ESP + catalyst, installed in those UFC restaurants ranged between 54.76 and 98.98%. The removal efficiency of PM by this control system was the least effective for particles with <0.4 μm, although those in the range of 0.4–10 μm were the most effective.

  11. Energetic Interrelationship between Spontaneous Low-Frequency Fluctuations in Regional Cerebral Blood Volume, Arterial Blood Pressure, Heart Rate, and Respiratory Rhythm

    Science.gov (United States)

    Katura, Takusige; Yagyu, Akihiko; Obata, Akiko; Yamazaki, Kyoko; Maki, Atsushi; Abe, Masanori; Tanaka, Naoki

    2007-07-01

    Strong spontaneous fluctuations around 0.1 and 0.3 Hz have been observed in blood-related brain-function measurements such as functional magnetic resonance imaging and optical topography (or functional near-infrared spectroscopy). These fluctuations seem to reflect the interaction between the cerebral circulation system and the systemic circulation system. We took an energetic viewpoint in our analysis of the interrelationships between fluctuations in cerebral blood volume (CBV), mean arterial blood pressure (MAP), heart rate (HR), and respiratory rhythm based on multivariate autoregressive modeling. This approach involves evaluating the contribution of each fluctuation or rhythm to specific ones by performing multivariate spectral analysis. The results we obtained show MAP and HR can account slightly for the fluctuation around 0.1 Hz in CBV, while the fluctuation around 0.3 Hz is derived mainly from the respiratory rhythm. During our presentation, we will report on the effects of posture on the interrelationship between the fluctuations and the respiratory rhythm.

  12. Primer on spontaneous heating and pyrophoricity

    Energy Technology Data Exchange (ETDEWEB)

    1994-12-01

    This primer was prepared as an information resource for personnel responsible for operation of DOE nuclear facilities. It has sections on combustion principles, spontaneous heating/ignition of hydrocarbons and organics, pyrophoric gases and liquids, pyrophoric nonmetallic solids, pyrophoric metals (including Pu and U), and accident case studies. Although the information in this primer is not all-encompassing, it should provide the reader with a fundamental knowledge level sufficient to recognize most spontaneous combustion hazards and how to prevent ignition and widespread fires. This primer is provided as an information resource only, and is not intended to replace any fire protection or hazardous material training.

  13. Rate of spontaneous voiding recovery after acute urinary retention due to bed rest in the hospital setting in a non-urological population clinical study of the relationship between lower limbs and bladder function

    Directory of Open Access Journals (Sweden)

    Paulo Rodrigues

    Full Text Available Abstract Objectives To understand the clinical relationship between lower limbs functions and the recovery of spontaneous voiding after an acute urinary retention (AUR in older patients admitted to hospitals for non-urological causes using clinical parameters. Materials and Methods 56 adult patients (32 men; mean age: 77.9 ± 8.3 and 24 women; mean age 82.1 ± 4.6 with AUR were prospectively followed with validated Physical Performance Mobility Exam (PPME instrument to evaluate the relationship between the recovery of mobility capacity and spontaneous voiding. After a short period of permanent bladder drainage patients started CIC along evaluation by PPME during hospitalization and at 7, 15, 30 60, 90, and 180 days of discharge. Mann-Whitney U, chi-square test and ANOVA tests were used. Results All patients were hospitalized for at least 15 days (Median 26.3 ± 4.1 days. Progressive improvement on mobility scale measured by PPME was observed after leaving ICU and along the initial 7 days of hospitalization but with a deterioration if hospitalization extends beyond 15 days (p<0.03. Prolonged hospital stay impairs mobility in all domains (p<0.05 except step-up and transfer skills (p<0.02 although a recovery rate on spontaneous voiding persistented. Restoration of spontaneous voiding was accompanied by improvement on mobility scale (p<0.02. Recovery of spontaneous voiding was markedly observed after discharging the hospital. All patients recovered spontaneous voiding until 6 months of follow-up. Conclusions Recovery to spontaneous voiding after acute urinary retention in the hospital setting may be anticipated by evaluation of lower limbs function measured by validated instruments.

  14. Glucagon-like peptide-1 acutely affects renal blood flow and urinary flow rate in spontaneously hypertensive rats despite significantly reduced renal expression of GLP-1 receptors.

    Science.gov (United States)

    Ronn, Jonas; Jensen, Elisa P; Wewer Albrechtsen, Nicolai J; Holst, Jens Juul; Sorensen, Charlotte M

    2017-12-01

    Glucagon-like peptide-1 (GLP-1) is an incretin hormone increasing postprandial insulin release. GLP-1 also induces diuresis and natriuresis in humans and rodents. The GLP-1 receptor is extensively expressed in the renal vascular tree in normotensive rats where acute GLP-1 treatment leads to increased mean arterial pressure (MAP) and increased renal blood flow (RBF). In hypertensive animal models, GLP-1 has been reported both to increase and decrease MAP. The aim of this study was to examine expression of renal GLP-1 receptors in spontaneously hypertensive rats (SHR) and to assess the effect of acute intrarenal infusion of GLP-1. We hypothesized that GLP-1 would increase diuresis and natriuresis and reduce MAP in SHR. Immunohistochemical staining and in situ hybridization for the GLP-1 receptor were used to localize GLP-1 receptors in the kidney. Sevoflurane-anesthetized normotensive Sprague-Dawley rats and SHR received a 20 min intrarenal infusion of GLP-1 and changes in MAP, RBF, heart rate, dieresis, and natriuresis were measured. The vasodilatory effect of GLP-1 was assessed in isolated interlobar arteries from normo- and hypertensive rats. We found no expression of GLP-1 receptors in the kidney from SHR. However, acute intrarenal infusion of GLP-1 increased MAP, RBF, dieresis, and natriuresis without affecting heart rate in both rat strains. These results suggest that the acute renal effects of GLP-1 in SHR are caused either by extrarenal GLP-1 receptors activating other mechanisms (e.g., insulin) to induce the renal changes observed or possibly by an alternative renal GLP-1 receptor. © 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

  15. Fire Perimeters

    Data.gov (United States)

    California Natural Resource Agency — The Fire Perimeters data consists of CDF fires 300 acres and greater in size and USFS fires 10 acres and greater throughout California from 1950 to 2003. Some fires...

  16. Fire History

    Data.gov (United States)

    California Natural Resource Agency — The Fire Perimeters data consists of CDF fires 300 acres and greater in size and USFS fires 10 acres and greater throughout California from 1950 to 2002. Some fires...

  17. Correlation of the corrosion rates of steels in a straw fired boiler with the thermodynamically predicted trend of KOH(g) in the flue gases

    International Nuclear Information System (INIS)

    Blomberg, Tom

    2012-01-01

    The thermodynamic stability of KOH(g) in flue gases without sulfur and chlorine compounds was studied. Relatively good correlation of the thermodynamically predicted trend of KOH(g) in the flue gases and the literature data of the corrosion rates of different steels in a straw fired boiler was found. A discussion on a possible, physically reasonable mechanism is also presented. However, the causality of the found correlation requires further studies. Highlights: ► Corrosion rates in a straw boiler correlate with the predicted trend of KOH(g). ► KOH(g) impinging the surface may be an important factor in corrosion in straw fired boilers. ► The proposed mechanism may be relevant also to other biomass fuels that release potassium hydroxide during combustion.

  18. Effects of electrical stimulation of ventral septal area on firing rates of pyrogen-treated thermosensitive neurons in preoptic anterior hypothalamus from rabbits.

    Science.gov (United States)

    Dong, Jun; Xie, Xin-Hua; Lu, Da-Xiang; Fu, Yong-Mei

    2007-01-09

    Although there is considerable evidence supporting that fever evolved as a host defense response, it is important that the rise in body temperature would not be too high. Many endogenous cryogens or antipyretics that limit the rise in body temperature have been identified. Endogenous antipyretics attenuate fever by influencing the thermoregulatory neurons in the preoptic anterior hypothalamus (POAH) and in adjacent septal areas including ventral septal area (VSA). Our previous study showed that intracerebroventricular (I.C.V.) injection of interleukin-1beta (IL-1beta) affected electrophysiological activities of thermosensitive neurons in VSA regions, and electrical stimulation of POAH reversed the effect of IL-1beta. To further investigate the functional electrophysiological connection between POAH and VSA and its mechanisms in thermoregulation, the firing rates of thermosensitive neurons in POAH of forty-seven unit discharge were recorded by using extracellular microelectrode technique in New Zealand white rabbits. Our results show that the firing rates of the warm-sensitive neurons decreased significantly and those of the cold-sensitive neurons increased in POAH when the pyrogen (IL-1beta) was injected I.C.V. The effects of IL-1beta on firing rates in thermosensitive neurons of POAH were reversed by electrical stimulation of VSA. An arginine vasopressin (AVP) V1 antagonist abolished the regulatory effects of VSA on the firing rates in thermosensitive neurons of POAH evoked by IL-1beta. However, an AVP V2 antagonist had no effects. These data indicated that VSA regulates the activities of the thermosensitive neurons of POAH through AVP V1 but not AVP V2 receptor.

  19. The Effects of Total Motile Sperm Count on Spontaneous Pregnancy Rate and Pregnancy After IUI Treatment in Couples with Male Factor and Unexplained Infertility.

    Science.gov (United States)

    Hajder, Mithad; Hajder, Elmira; Husic, Amela

    2016-02-01

    Male infertility factor is defined if the total number of motile spermatozoa (TMSC) 3,10(6) / ejaculate and a spontaneous pregnancy, group (B) with TMSCl 3 x 10(6) / ejaculate and couples who have not achieved pregnancy. From a total of 98 pairs of men's and unexplained infertility, 42 of them (42.8%) achieved spontaneous pregnancy, while 56 (57.2%) pairs did not achieve spontaneous pregnancy. TMSC was significantly higher (42.4 ± 28.4 vs. 26.2 ± 24, p 20 x 10(6) / ejaculate (RR = 1.7, 95% CI: 1.56-1.82, 5 x 10(6) / ejaculate are indicated for treatment with IUI. TMSC can be used as the method of choice for diagnosis and treatment of male infertility.

  20. A Review of Fire Interactions and Mass Fires

    Directory of Open Access Journals (Sweden)

    Mark A. Finney

    2011-01-01

    Full Text Available The character of a wildland fire can change dramatically in the presence of another nearby fire. Understanding and predicting the changes in behavior due to fire-fire interactions cannot only be life-saving to those on the ground, but also be used to better control a prescribed fire to meet objectives. In discontinuous fuel types, such interactions may elicit fire spread where none otherwise existed. Fire-fire interactions occur naturally when spot fires start ahead of the main fire and when separate fire events converge in one location. Interactions can be created intentionally during prescribed fires by using spatial ignition patterns. Mass fires are among the most extreme examples of interactive behavior. This paper presents a review of the detailed effects of fire-fire interaction in terms of merging or coalescence criteria, burning rates, flame dimensions, flame temperature, indraft velocity, pulsation, and convection column dynamics. Though relevant in many situations, these changes in fire behavior have yet to be included in any operational-fire models or decision support systems.

  1. [Spontaneous hypoglycemia].

    Science.gov (United States)

    Ellorhaoui, M; Schultze, W

    1977-01-15

    On the basis of a survey is attempted to describe mode of development, symptomatology, individual forms and the different possibilities of therapy of the spontaneous hypoglycaemias. A particularly broad range was devoted to the cerebral sequelae, since in these cases--according to our experience--on account of simulation of neurologico-psychiatric symptoms at the soonest wrong diagnoses are to be expected. Furthermore, it is attempted to classify the hypoglycemias according to their development, in which cases their incompleteness was evident from the very beginning. The individual forms of appearance are treated according their to significance. Out of the inducible hypoglycaemias a particular attention is devoted to the forms caused by insulin and oral antidiabetics, since these most frequently participate in the development. Finally the author inquires into diagnostic measures for recognition of special forms of hypoglycaemia. In this place the diagnostics of hyperinsulinism conditioned by adenomatosis or tumours of other kinds is of particular importance. Finally conservative and operative possibilities of the therapy of these tumours are discussed,whereby the only recently tested treatment with streptotocin is mentioned.

  2. Cytologic anaplasia is a prognostic factor in osteosarcoma biopsies, but mitotic rate or extent of spontaneous tumor necrosis are not: a critique of the College of American Pathologists Bone Biopsy template.

    Science.gov (United States)

    Cates, Justin Mm; Dupont, William D

    2017-01-01

    The current College of American Pathologists cancer template for reporting biopsies of bone tumors recommends including information that is of unproven prognostic significance for osteosarcoma, such as the presence of spontaneous tumor necrosis and mitotic rate. Conversely, the degree of cytologic anaplasia (degree of differentiation) is not reported in this template. This retrospective cohort study of 125 patients with high-grade osteosarcoma was performed to evaluate the prognostic impact of these factors in diagnostic biopsy specimens in predicting the clinical outcome and response to neoadjuvant chemotherapy. Multivariate Cox regression was performed to adjust survival analyses for well-established prognostic factors. Multivariate logistic regression was used to determine odds ratios for good chemotherapy response (≥90% tumor necrosis). Osteosarcomas with severe anaplasia were independently associated with increased overall and disease-free survival, but mitotic rate and spontaneous necrosis had no prognostic impact after controlling for other confounding factors. Mitotic rate showed a trend towards increased odds of a good histologic response, but this effect was diminished after controlling for other predictive factors. Neither spontaneous necrosis nor the degree of cytologic anaplasia observed in biopsy specimens was predictive of a good response to chemotherapy. Mitotic rate and spontaneous tumor necrosis observed in pretreatment biopsy specimens of high-grade osteosarcoma are not strong independent prognostic factors for clinical outcome or predictors of response to neoadjuvant chemotherapy. Therefore, reporting these parameters for osteosarcoma, as recommended in the College of American Pathologists Bone Biopsy template, does not appear to have clinical utility. In contrast, histologic grading schemes for osteosarcoma based on the degree of cytologic anaplasia may have independent prognostic value and should continue to be evaluated.

  3. Simulating spatial and temporally related fire weather

    Science.gov (United States)

    Isaac C. Grenfell; Mark Finney; Matt Jolly

    2010-01-01

    Use of fire behavior models has assumed an increasingly important role for managers of wildfire incidents to make strategic decisions. For fire risk assessments and danger rating at very large spatial scales, these models depend on fire weather variables or fire danger indices. Here, we describe a method to simulate fire weather at a national scale that captures the...

  4. Charts for interpreting wildland fire behavior characteristics

    Science.gov (United States)

    Patricia L. Andrews; Richard C. Rothermel

    1982-01-01

    The fire characteristics chart is proposed as a graphical method ofpresenting two primary characteristics of fire behavior – spread rate and intensity. Its primary use is communicating and interpreting either site-specific predictions of fire behavior or National Fire-Danger Rating System (NFDRS) indexes and components. Rate of spread, heat per unit area, flame length...

  5. The eukaryotic bell-shaped temporal rate of DNA replication origin firing emanates from a balance between origin activation and passivation.

    Science.gov (United States)

    Arbona, Jean-Michel; Goldar, Arach; Hyrien, Olivier; Arneodo, Alain; Audit, Benjamin

    2018-06-01

    The time-dependent rate I(t) of origin firing per length of unreplicated DNA presents a universal bell shape in eukaryotes that has been interpreted as the result of a complex time-evolving interaction between origins and limiting firing factors. Here we show that a normal diffusion of replication fork components towards localized potential replication origins (p-oris) can more simply account for the I(t) universal bell shape, as a consequence of a competition between the origin firing time and the time needed to replicate DNA separating two neighboring p-oris . We predict the I(t) maximal value to be the product of the replication fork speed with the squared p-ori density. We show that this relation is robustly observed in simulations and in experimental data for several eukaryotes. Our work underlines that fork-component recycling and potential origins localization are sufficient spatial ingredients to explain the universality of DNA replication kinetics. © 2018, Arbona et al.

  6. Impacts of the post-fire erosion processes compared with the agricultural erosion rates for a mountain catchment in NW Iberia

    Science.gov (United States)

    Marisa Santos, Juliana; Nunes, João Pedro; Bernard-Jannin, Léonard; Gonzalez Pelayo, Oscar; Keizer, Jan Jacob

    2014-05-01

    after forest fires. The last forest fire in August 2011 burned 10% of the total area in the north-west part of the catchment. Post-fire management operations 9 month after the fire (clear-cutting and deep plowing operations) and after plantation of "Quercus robur" left the soil exposed, and relatively mild rainstorms led to large amounts of soil loss, including a large amount of rills and other erosion features. This constituted an opportunity to compare these erosion rates with the ones observed in agricultural fields for similar edapho-climatic conditions, and also observe distinct timing of erosion occurrence which was linked with different periods when soils are exposed. This communication presents the assessment of the impact of this fire on soil erosion rates, where results indicate that soil losses after soil preparation for forest replanting might be equivalent, in long-term, to soil losses in agricultural fields.

  7. Preictal activity of subicular, CA1, and dentate gyrus principal neurons in the dorsal hippocampus before spontaneous seizures in a rat model of temporal lobe epilepsy.

    Science.gov (United States)

    Fujita, Satoshi; Toyoda, Izumi; Thamattoor, Ajoy K; Buckmaster, Paul S

    2014-12-10

    Previous studies suggest that spontaneous seizures in patients with temporal lobe epilepsy might be preceded by increased action potential firing of hippocampal neurons. Preictal activity is potentially important because it might provide new opportunities for predicting when a seizure is about to occur and insight into how spontaneous seizures are generated. We evaluated local field potentials and unit activity of single, putative excitatory neurons in the subiculum, CA1, CA3, and dentate gyrus of the dorsal hippocampus in epileptic pilocarpine-treated rats as they experienced spontaneous seizures. Average action potential firing rates of neurons in the subiculum, CA1, and dentate gyrus, but not CA3, increased significantly and progressively beginning 2-4 min before locally recorded spontaneous seizures. In the subiculum, CA1, and dentate gyrus, but not CA3, 41-57% of neurons displayed increased preictal activity with significant consistency across multiple seizures. Much of the increased preictal firing of neurons in the subiculum and CA1 correlated with preictal theta activity, whereas preictal firing of neurons in the dentate gyrus was independent of theta. In addition, some CA1 and dentate gyrus neurons displayed reduced firing rates preictally. These results reveal that different hippocampal subregions exhibit differences in the extent and potential underlying mechanisms of preictal activity. The finding of robust and significantly consistent preictal activity of subicular, CA1, and dentate neurons in the dorsal hippocampus, despite the likelihood that many seizures initiated in other brain regions, suggests the existence of a broader neuronal network whose activity changes minutes before spontaneous seizures initiate. Copyright © 2014 the authors 0270-6474/14/3416671-17$15.00/0.

  8. Moderate Image Spectrometer (MODIS) Fire Radiative Energy: Physics and Applications

    Science.gov (United States)

    Kaufman, Y.

    2004-01-01

    MODIS fire channel does not saturate in the presence of fires. The fire channel therefore is used to estimate the fire radiative energy, a measure of the rate of biomass consumption in the fire. We found correlation between the fire radiative energy, the rate of formation of burn scars and the rate of emission of aerosol from the fires. Others found correlations between the fire radiative energy and the rate of biomass consumption. This relationships can be used to estimates the emissions from the fires and to estimate the fire hazards.

  9. Analytical model for cable tray fires

    International Nuclear Information System (INIS)

    Clarke, R.K.

    1975-09-01

    A model for cable tray fires based on buoyant plume theory is presented. Using the model in conjunction with empirical data on size of natural fires and burning rate of cellulosic materials, estimates are made of the heat flux as a function of vertical and horizontal distance from a tray fire. Both local fires and fires extending along a significant length of tray are considered. For the particular set of fire parameters assumed in the calculations, the current tray separation criteria of five feet vertical and three feet horizontal are found to be marginal for local fires and too small to prevent fire spread for extended tray fires. 8 references. (auth)

  10. α and β deuterium isotope effects in the hydrolysis of naphthalene tetrahydro epoxides: rate-limiting hydrogen migration in the spontaneous hydrolysis of 6-methoxy-1,2,3,4-tetrahydronaphthalene oxide

    International Nuclear Information System (INIS)

    Gillilan, R.E.; Pohl, T.M.; Whalen, D.L.

    1982-01-01

    Data are reported that indicate that 6-methoxy-1,2,3-tetrahydronaphthalene oxide undergoes a spontaneous reaction to yield mostly 6-methyoxy-2-tetralone. Hydrogen-migration is reported to be the rate determining step in the reaction. Reaction mechanisms involving a one-step reaction with a concurrent C-O bond cleavage and hydrogen migration or reversible C-O bond cleavage followed by the rate-limiting hydrogen migration are proposed, but no clear distinction between the schemes is made

  11. Fire risk in California

    Science.gov (United States)

    Peterson, Seth Howard

    Fire is an integral part of ecosystems in the western United States. Decades of fire suppression have led to (unnaturally) large accumulations of fuel in some forest communities, such as the lower elevation forests of the Sierra Nevada. Urban sprawl into fire prone chaparral vegetation in southern California has put human lives at risk and the decreased fire return intervals have put the vegetation community at risk of type conversion. This research examines the factors affecting fire risk in two of the dominant landscapes in the state of California, chaparral and inland coniferous forests. Live fuel moisture (LFM) is important for fire ignition, spread rate, and intensity in chaparral. LFM maps were generated for Los Angeles County by developing and then inverting robust cross-validated regression equations from time series field data and vegetation indices (VIs) and phenological metrics from MODIS data. Fire fuels, including understory fuels which are not visible to remote sensing instruments, were mapped in Yosemite National Park using the random forests decision tree algorithm and climatic, topographic, remotely sensed, and fire history variables. Combining the disparate data sources served to improve classification accuracies. The models were inverted to produce maps of fuel models and fuel amounts, and these showed that fire fuel amounts are highest in the low elevation forests that have been most affected by fire suppression impacting the natural fire regime. Wildland fires in chaparral commonly burn in late summer or fall when LFM is near its annual low, however, the Jesusita Fire burned in early May of 2009, when LFM was still relatively high. The HFire fire spread model was used to simulate the growth of the Jesusita Fire using LFM maps derived from imagery acquired at the time of the fire and imagery acquired in late August to determine how much different the fire would have been if it had occurred later in the year. Simulated fires were 1.5 times larger

  12. Modeling of compartment fire

    International Nuclear Information System (INIS)

    Sathiah, P.; Siccama, A.; Visser, D.; Komen, E.

    2011-01-01

    Fire accident in a containment is a serious threat to nuclear reactors. Fire can cause substantial loss to life and property. The risk posed by fire can also exceed the risk from internal events within a nuclear reactor. Numerous research efforts have been performed to understand and analyze the phenomenon of fire in nuclear reactor and its consequences. Modeling of fire is an important subject in the field of fire safety engineering. Two approaches which are commonly used in fire modeling are zonal modeling and field modeling. The objective of this work is to compare zonal and field modeling approach against a pool fired experiment performed in a well-confined compartment. Numerical simulations were performed against experiments, which were conducted within PRISME program under the framework of OECD. In these experiments, effects of ventilation flow rate on heat release rate in a confined and mechanically ventilated compartment is investigated. Time dependent changes in gas temperature and oxygen mass fraction were measured. The trends obtained by numerical simulation performed using zonal model and field model compares well with experiments. Further validation is needed before this code can be used for fire safety analyses. (author)

  13. Aerosol generation from Kerosene fires

    International Nuclear Information System (INIS)

    Jordan, S.; Lindner, W.

    1981-01-01

    The course of solvent surface fires is dependent on the surface area on fire; depth of pool and solvent composition do not influence the fire rate. But the fire rate increases rapidly with the burning area. The residual oxygen concentration after a fire in a closed container is dependent on the violence of the fire, i.e. on the burning surface. Moreover the ending of the fire is influenced by the TBP-concentration of the solvent. With sufficient supply of solvent the TBP-concentration changes only slightly during the fire, so that a fire at 14% O 2 -concentration is extinguished within the container. With the TBP-concentration changing considerably, i.e. little mass, a fire with a similar burning surface is already extinguished at an O 2 -content of 18%. The aerosol generation depends on the fire rate, and so it is higher in free atmosphere than in closed containers. The soot production in the mixture fire (kerosene /TBP 70/30) is higher by a factor 7 than in the pure kerosene fire. Primary soot-particles have a diameter of approximately 0,05 μm and agglomerate rapidly into aggregates of 0,2-0,4 μm. (orig.) [de

  14. How to generate and interpret fire characteristics charts for surface and crown fire behavior

    Science.gov (United States)

    Patricia L. Andrews; Faith Ann Heinsch; Luke Schelvan

    2011-01-01

    A fire characteristics chart is a graph that presents primary related fire behavior characteristics-rate of spread, flame length, fireline intensity, and heat per unit area. It helps communicate and interpret modeled or observed fire behavior. The Fire Characteristics Chart computer program plots either observed fire behavior or values that have been calculated by...

  15. Quantitative comparison of fire danger index performance using fire activity

    CSIR Research Space (South Africa)

    Steenkamp, KC

    2012-07-01

    Full Text Available parameters such as flame length or rate of spread can be physically measured or modeled. Fire danger indices are not designed to describe the characteristics of a fire but rather the potential of a fire taking place in an area of interest [5]. Several...

  16. Summary of HEDL sodium fire tests

    Energy Technology Data Exchange (ETDEWEB)

    Hilliard, R K [Hanford Engineering Development Laboratory, Richland, WA (United States)

    1979-03-01

    The sodium fire test program and related studies at the Hanford Engineering Development Laboratory (HEDL), covering the period from 1972 to 1978, are described. The program is analytical and experimental in scope, with computer code development and experimental verification. Tests have ranged in size from gram quantity laboratory tests to 1600-kg sodium spills. The experimental work is performed in two facilities: the Large Sodium Fire Facility (LSFF) and the Containment Systems Test Facility (CSTF). The facilities are described and the experimental results summarized. Sodium fire extinguishment tests which verified the Fast Flux Test Facility (FFTF) secondary sodium fire protection system are described and related information on sodium burning rates and smoke release rates are correlated. The burning rates are compared to theoretical predictions based on heat and mass transfer analogy, with good agreement. Comparisons with the SOFIRE-II code are also made. Sodium combustion aerosol properties are defined as to chemical and physical nature, settling in closed vessels and effect of added water vapor. The HAA-38 aerosol behaviour computer code is compared to tests in the 850-m{sup 3} CSTF containment vessel. Sodium spray tests in the CSTF are compared with the SPRAY computer code. An air cleaning program is described, which has the objective of removing high mass concentration sodium combustion aerosols from vented cells and containment buildings. The aerosol mass holding capacity of commercial filters was measured and an aqueous scrubber system is described. The effects of sodium spills on cell structures were investigated, including water release from heated concrete, the reaction of sodium with concrete, the formation and spontaneous recombination of hydrogen, and the ability of steel cell liners to withstand large spills of high temperature sodium without leaking. (author)

  17. Summary of HEDL sodium fire tests

    International Nuclear Information System (INIS)

    Hilliard, R.K.

    1979-01-01

    The sodium fire test program and related studies at the Hanford Engineering Development Laboratory (HEDL), covering the period from 1972 to 1978, are described. The program is analytical and experimental in scope, with computer code development and experimental verification. Tests have ranged in size from gram quantity laboratory tests to 1600-kg sodium spills. The experimental work is performed in two facilities: the Large Sodium Fire Facility (LSFF) and the Containment Systems Test Facility (CSTF). The facilities are described and the experimental results summarized. Sodium fire extinguishment tests which verified the Fast Flux Test Facility (FFTF) secondary sodium fire protection system are described and related information on sodium burning rates and smoke release rates are correlated. The burning rates are compared to theoretical predictions based on heat and mass transfer analogy, with good agreement. Comparisons with the SOFIRE-II code are also made. Sodium combustion aerosol properties are defined as to chemical and physical nature, settling in closed vessels and effect of added water vapor. The HAA-38 aerosol behaviour computer code is compared to tests in the 850-m 3 CSTF containment vessel. Sodium spray tests in the CSTF are compared with the SPRAY computer code. An air cleaning program is described, which has the objective of removing high mass concentration sodium combustion aerosols from vented cells and containment buildings. The aerosol mass holding capacity of commercial filters was measured and an aqueous scrubber system is described. The effects of sodium spills on cell structures were investigated, including water release from heated concrete, the reaction of sodium with concrete, the formation and spontaneous recombination of hydrogen, and the ability of steel cell liners to withstand large spills of high temperature sodium without leaking. (author)

  18. Summary of HEDL sodium fire tests

    International Nuclear Information System (INIS)

    Hillard, R.K.

    1978-10-01

    The sodium fire test program and related studies at the Hanford Engineering Development Laboratory (HEDL) are described. The program is analytical and experimental in scope, with computer code development and experimental verification. Tests have ranged in size from gram quantity laboratory tests to 1600-kg sodium spills. The experimental work is performed in two facilities: the Large Sodium Fire Facility (LSFF) and the Containment Systems Test Facility (CSTF). Sodium fire extinguishment tests which verified the Fast Flux Test Facility (FFTF) secondary sodium fire protection system are described and related informaion on sodium burning rates and smoke release rates are correlated. The burning rates are compared to theoretical predictions based on heat and mass transfer analogy, with good agreement. Comparisons with the SOFIRE-II code are also made. Sodium combustion aerosol properties are defined as to chemical and physical nature, settling in closed vessels and effect of added water vapor. The HAA-3B aerosol behavior computer code is compared to tests in the 850-m 3 CSTF containment vessel. Sodium spray tests in the CSTF are compared with the SPRAY computer code. An air cleaning program is described, which has the objective of removing high mass concentration sodium combustion aerosols from vented cells and containment buildings. The aerosol mass holding capacity of commercial filters was measured and an aqueous scrubber system is described. The effects of sodium spills on cell structures were investigated, including water release from heated concrete, the reaction of sodium with concrete, the formation and spontaneous recombination of hydrogen, and the ability of steel cell liners to withstand large spills of high temperature sodium without leaking

  19. Designing fire safe interiors.

    Science.gov (United States)

    Belles, D W

    1992-01-01

    Any product that causes a fire to grow large is deficient in fire safety performance. A large fire in any building represents a serious hazard. Multiple-death fires almost always are linked to fires that grow quickly to a large size. Interior finishes have large, continuous surfaces over which fire can spread. They are regulated to slow initial fire growth, and must be qualified for use on the basis of fire tests. To obtain meaningful results, specimens must be representative of actual installation. Variables--such as the substrate, the adhesive, and product thickness and density--can affect product performance. The tunnel test may not adequately evaluate some products, such as foam plastics or textile wall coverings, thermoplastic materials, or materials of minimal mass. Where questions exist, products should be evaluated on a full-scale basis. Curtains and draperies are examples of products that ignite easily and spread flames readily. The present method for testing curtains and draperies evaluates one fabric at a time. Although a fabric tested alone may perform well, fabrics that meet test standards individually sometimes perform poorly when tested in combination. Contents and furnishings constitute the major fuels in many fires. Contents may involve paper products and other lightweight materials that are easily ignited and capable of fast fire growth. Similarly, a small source may ignite many items of furniture that are capable of sustained fire growth. Upholstered furniture can reach peak burning rates in less than 5 minutes. Furnishings have been associated with many multiple-death fires.(ABSTRACT TRUNCATED AT 250 WORDS)

  20. Fire protection

    International Nuclear Information System (INIS)

    Janetzky, E.

    1980-01-01

    Safety and fire prevention measurements have to be treated like the activities developing, planning, construction and erection. Therefore it is necessary that these measurements have to be integrated into the activities mentioned above at an early stage in order to guarantee their effectiveness. With regard to fire accidents the statistics of the insurance companies concerned show that the damage caused increased in the last years mainly due to high concentration of material. Organization of fire prevention and fire fighting, reasons of fire break out, characteristics and behaviour of fire, smoke and fire detection, smoke and heat venting, fire extinguishers (portable and stationary), construction material in presence of fire, respiratory protection etc. will be discussed. (orig./RW)

  1. Fear Expression Suppresses Medial Prefrontal Cortical Firing in Rats.

    Directory of Open Access Journals (Sweden)

    Thomas F Giustino

    Full Text Available The medial prefrontal cortex (mPFC plays a crucial role in emotional learning and memory in rodents and humans. While many studies suggest a differential role for the prelimbic (PL and infralimbic (IL subdivisions of mPFC, few have considered the relationship between neural activity in these two brain regions recorded simultaneously in behaving animals. Importantly, how concurrent PL and IL activity relate to conditioned freezing behavior is largely unknown. Here we used single-unit recordings targeting PL and IL in awake, behaving rats during the acquisition and expression of conditioned fear. On Day 1, rats received either signaled or unsignaled footshocks in the recording chamber; an auditory conditioned stimulus (CS preceded signaled footshocks. Twenty-four hours later, animals were returned to the recording chamber (modified to create a novel context where they received 5 CS-alone trials. After fear conditioning, both signaled and unsignaled rats exhibited high levels of post-shock freezing that was associated with an enduring suppression of mPFC spontaneous firing, particularly in the IL of signaled rats. Twenty-four hours later, CS presentation produced differential conditioned freezing in signaled and unsignaled rats: freezing increased in rats that had received signaled shocks, but decreased in animals in the unsignaled condition (i.e., external inhibition. This group difference in CS-evoked freezing was mirrored in the spontaneous firing rate of neurons in both PL and IL. Interestingly, differences in PL and IL firing rate highly correlated with freezing levels. In other words, in the signaled group IL spontaneous rates were suppressed relative to PL, perhaps limiting IL-mediated suppression of fear and allowing PL activity to dominate performance, resulting in high levels of freezing. This was not observed in the unsignaled group, which exhibited low freezing. These data reveal that the activity of mPFC neurons is modulated by both

  2. Improvement of Forest Fire Detection Algorithm Using Brightness Temperature Lapse Rate Correction in HIMAWARI-8 IR Channels: Application to the 6 may 2017 Samcheok City, Korea

    Science.gov (United States)

    Park, S. H.; Park, W.; Jung, H. S.

    2018-04-01

    Forest fires are a major natural disaster that destroys a forest area and a natural environment. In order to minimize the damage caused by the forest fire, it is necessary to know the location and the time of day and continuous monitoring is required until fire is fully put out. We have tried to improve the forest fire detection algorithm by using a method to reduce the variability of surrounding pixels. We focused that forest areas of East Asia, part of the Himawari-8 AHI coverage, are mostly located in mountainous areas. The proposed method was applied to the forest fire detection in Samcheok city, Korea on May 6 to 10, 2017.

  3. Ketogenic diet metabolites reduce firing in central neurons by opening K(ATP) channels.

    Science.gov (United States)

    Ma, Weiyuan; Berg, Jim; Yellen, Gary

    2007-04-04

    A low-carbohydrate ketogenic diet remains one of the most effective (but mysterious) treatments for severe pharmacoresistant epilepsy. We have tested for an acute effect of physiological ketone bodies on neuronal firing rates and excitability, to discover possible therapeutic mechanisms of the ketogenic diet. Physiological concentrations of ketone bodies (beta-hydroxybutyrate or acetoacetate) reduced the spontaneous firing rate of neurons in slices from rat or mouse substantia nigra pars reticulata. This region is thought to act as a "seizure gate," controlling seizure generalization. Consistent with an anticonvulsant role, the ketone body effect is larger for cells that fire more rapidly. The effect of ketone bodies was abolished by eliminating the metabolically sensitive K(ATP) channels pharmacologically or by gene knock-out. We propose that ketone bodies or glycolytic restriction treat epilepsy by augmenting a natural activity-limiting function served by K(ATP) channels in neurons.

  4. Chapter 6: Fire damage of wood structures

    Science.gov (United States)

    B. Kukay; R.H. White; F. Woeste

    2012-01-01

    Depending on the severity, fire damage can compromise the structural integrity of wood structures such as buildings or residences. Fire damage of wood structures can incorporate several models that address (1) the type, cause, and spread of the fire, (2) the thermal gradients and fire-resistance ratings, and (3) the residual load capacity (Figure 6.1). If there is a...

  5. Fire Stations

    Data.gov (United States)

    Department of Homeland Security — Fire Stations in the United States Any location where fire fighters are stationed or based out of, or where equipment that such personnel use in carrying out their...

  6. Spontaneous soft tissue hematomas.

    Science.gov (United States)

    Dohan, A; Darnige, L; Sapoval, M; Pellerin, O

    2015-01-01

    Spontaneous muscle hematomas are a common and serious complication of anticoagulant treatment. The incidence of this event has increased along with the rise in the number of patients receiving anticoagulants. Radiological management is both diagnostic and interventional. Computed tomography angiography (CTA) is the main tool for the detection of hemorrhage to obtain a positive, topographic diagnosis and determine the severity. Detection of an active leak of contrast material during the arterial or venous phase is an indication for the use of arterial embolization. In addition, the interventional radiological procedure can be planned with CTA. Arterial embolization of the pedicles that are the source of the bleeding is an effective technique. The rate of technical and clinical success is 90% and 86%, respectively. Copyright © 2015 Éditions françaises de radiologie. Published by Elsevier Masson SAS. All rights reserved.

  7. Spontaneous transition rates for electric dipole (E1), magnetic dipole (M1), electric quadrupole (E2) and magnetic quadrupole (M2) transitions for He-like calcium and sulfur ions

    International Nuclear Information System (INIS)

    Kingston, A.E.; Norrington, P.H.; Boone, A.W.

    2002-01-01

    The spontaneous decay rates for the electric dipole (E1), electric quadrupole (E2), magnetic dipole (M1) and magnetic quadrupole (M2) transitions between all of the 1s 2 , 1s2 l and 1s3 l states have been obtained for helium-like calcium and sulfur ions. To assess the accuracy of the calculations, the transition probabilities were calculated using two sets of configuration interaction wavefunctions. One set of wavefunctions was generated using the fully relativistic GRASP code and the other was obtained using CIV3, in which relativistic effects are introduced using the Breit-Pauli approximation. The transition rates, A values, oscillator strengths and line strengths from our two calculations are found to be similar and to compare very well with other recent results for Δn=1 or 2 transitions. For Δn=0 transitions the agreement is much less good; this is mainly due to differences in the calculated excitation energies. (author)

  8. Adsorber fires

    International Nuclear Information System (INIS)

    Holmes, W.

    1987-01-01

    The following conclusions are offered with respect to activated charcoal filter systems in nuclear power plants: (1) The use of activated charcoal in nuclear facilities presents a potential for deep-seated fires. (2) The defense-in-depth approach to nuclear fire safety requires that if an ignition should occur, fires must be detected quickly and subsequently suppressed. (3) Deep-seated fires in charcoal beds are difficult to extinguish. (4) Automatic water sprays can be used to extinguish fires rapidly and reliably when properly introduced into the burning medium. The second part of the conclusions offered are more like challenges: (1) The problem associated with inadvertent actuations of fire protection systems is not a major one, and it can be reduced further by proper design review, installation, testing, and maintenance. Eliminating automatic fire extinguishing systems for the protection of charcoal adsorbers is not justified. (2) Removal of automatic fire protection systems due to fear of inadvertent fire protection system operation is a case of treating the effect rather than the cause. On the other hand, properly maintaining automatic fire protection systems will preserve the risk of fire loss at acceptable levels while at the same time reducing the risk of damage presented by inadvertent operation of fire protection systems

  9. Bistable firing properties of soleus motor units in unrestrained rats

    DEFF Research Database (Denmark)

    EKEN, T.; KIEHN, O.

    1989-01-01

    of the motoneuron pool by stimulation of la afferents, or inhibition by stimulation of skin afferents. The shifts were not related to gross limb movements. This phenomenon is referred to as a bistable firing pattern. Bistable firing also occurred spontaneously during quiet standing. Typically the firing frequency...... was unchanged or only phasically influenced. These results demonstrate for the first time a bistable firing pattern during postural activity in the intact animal. The firing pattern closely resembles the bistable behaviour described in spinal motoneurons in reduced preparations, where it is due to the presence...... of a plateau potential. This suggests that the bistable firing is unexplained by plateau potentials also in the intact animal....

  10. US Fire Administration Fire Statistics

    Data.gov (United States)

    Department of Homeland Security — The U.S. Fire Administration collects data from a variety of sources to provide information and analyses on the status and scope of the fire problem in the United...

  11. Fire test database

    International Nuclear Information System (INIS)

    Lee, J.A.

    1989-01-01

    This paper describes a project recently completed for EPRI by Impell. The purpose of the project was to develop a reference database of fire tests performed on non-typical fire rated assemblies. The database is designed for use by utility fire protection engineers to locate test reports for power plant fire rated assemblies. As utilities prepare to respond to Information Notice 88-04, the database will identify utilities, vendors or manufacturers who have specific fire test data. The database contains fire test report summaries for 729 tested configurations. For each summary, a contact is identified from whom a copy of the complete fire test report can be obtained. Five types of configurations are included: doors, dampers, seals, wraps and walls. The database is computerized. One version for IBM; one for Mac. Each database is accessed through user-friendly software which allows adding, deleting, browsing, etc. through the database. There are five major database files. One each for the five types of tested configurations. The contents of each provides significant information regarding the test method and the physical attributes of the tested configuration. 3 figs

  12. Forest fires

    International Nuclear Information System (INIS)

    Fuller, M.

    1991-01-01

    This book examines the many complex and sensitive issues relating to wildland fires. Beginning with an overview of the fires of 1980s, the book discusses the implications of continued drought and considers the behavior of wildland fires, from ignition and spread to spotting and firestorms. Topics include the effects of weather, forest fuels, fire ecology, and the effects of fire on plants and animals. In addition, the book examines firefighting methods and equipment, including new minimum impact techniques and compressed air foam; prescribed burning; and steps that can be taken to protect individuals and human structures. A history of forest fire policies in the U.S. and a discussion of solutions to fire problems around the world completes the coverage. With one percent of the earth's surface burning every year in the last decade, this is a penetrating book on a subject of undeniable importance

  13. Measuring fire size in tunnels

    International Nuclear Information System (INIS)

    Guo, Xiaoping; Zhang, Qihui

    2013-01-01

    A new measure of fire size Q′ has been introduced in longitudinally ventilated tunnel as the ratio of flame height to the height of tunnel. The analysis in this article has shown that Q′ controls both the critical velocity and the maximum ceiling temperature in the tunnel. Before the fire flame reaches tunnel ceiling (Q′ 1.0), Fr approaches a constant value. This is also a well-known phenomenon in large tunnel fires. Tunnel ceiling temperature shows the opposite trend. Before the fire flame reaches the ceiling, it increases very slowly with the fire size. Once the flame has hit the ceiling of tunnel, temperature rises rapidly with Q′. The good agreement between the current prediction and three different sets of experimental data has demonstrated that the theory has correctly modelled the relation among the heat release rate of fire, ventilation flow and the height of tunnel. From design point of view, the theoretical maximum of critical velocity for a given tunnel can help to prevent oversized ventilation system. -- Highlights: • Fire sizing is an important safety measure in tunnel design. • New measure of fire size a function of HRR of fire, tunnel height and ventilation. • The measure can identify large and small fires. • The characteristics of different fire are consistent with observation in real fires

  14. Distinct Temporal Coordination of Spontaneous Population Activity between Basal Forebrain and Auditory Cortex

    Directory of Open Access Journals (Sweden)

    Josue G. Yague

    2017-09-01

    Full Text Available The basal forebrain (BF has long been implicated in attention, learning and memory, and recent studies have established a causal relationship between artificial BF activation and arousal. However, neural ensemble dynamics in the BF still remains unclear. Here, recording neural population activity in the BF and comparing it with simultaneously recorded cortical population under both anesthetized and unanesthetized conditions, we investigate the difference in the structure of spontaneous population activity between the BF and the auditory cortex (AC in mice. The AC neuronal population show a skewed spike rate distribution, a higher proportion of short (≤80 ms inter-spike intervals (ISIs and a rich repertoire of rhythmic firing across frequencies. Although the distribution of spontaneous firing rate in the BF is also skewed, a proportion of short ISIs can be explained by a Poisson model at short time scales (≤20 ms and spike count correlations are lower compared to AC cells, with optogenetically identified cholinergic cell pairs showing exceptionally higher correlations. Furthermore, a smaller fraction of BF neurons shows spike-field entrainment across frequencies: a subset of BF neurons fire rhythmically at slow (≤6 Hz frequencies, with varied phase preferences to ongoing field potentials, in contrast to a consistent phase preference of AC populations. Firing of these slow rhythmic BF cells is correlated to a greater degree than other rhythmic BF cell pairs. Overall, the fundamental difference in the structure of population activity between the AC and BF is their temporal coordination, in particular their operational timescales. These results suggest that BF neurons slowly modulate downstream populations whereas cortical circuits transmit signals on multiple timescales. Thus, the characterization of the neural ensemble dynamics in the BF provides further insight into the neural mechanisms, by which brain states are regulated.

  15. Forest fires in Pennsylvania.

    Science.gov (United States)

    Donald A. Haines; William A. Main; Eugene F. McNamara

    1978-01-01

    Describes factors that contribute to forest fires in Pennsylvania. Includes an analysis of basic statistics; distribution of fires during normal, drought, and wet years; fire cause, fire activity by day-of-week; multiple-fire day; and fire climatology.

  16. Calculation of Fire Severity Factors and Fire Non-Suppression Probabilities For A DOE Facility Fire PRA

    International Nuclear Information System (INIS)

    Elicson, Tom; Harwood, Bentley; Lucek, Heather; Bouchard, Jim

    2011-01-01

    Over a 12 month period, a fire PRA was developed for a DOE facility using the NUREG/CR-6850 EPRI/NRC fire PRA methodology. The fire PRA modeling included calculation of fire severity factors (SFs) and fire non-suppression probabilities (PNS) for each safe shutdown (SSD) component considered in the fire PRA model. The SFs were developed by performing detailed fire modeling through a combination of CFAST fire zone model calculations and Latin Hypercube Sampling (LHS). Component damage times and automatic fire suppression system actuation times calculated in the CFAST LHS analyses were then input to a time-dependent model of fire non-suppression probability. The fire non-suppression probability model is based on the modeling approach outlined in NUREG/CR-6850 and is supplemented with plant specific data. This paper presents the methodology used in the DOE facility fire PRA for modeling fire-induced SSD component failures and includes discussions of modeling techniques for: Development of time-dependent fire heat release rate profiles (required as input to CFAST), Calculation of fire severity factors based on CFAST detailed fire modeling, and Calculation of fire non-suppression probabilities.

  17. Spontaneous external gallbladder perforation

    International Nuclear Information System (INIS)

    Noeldge, G.; Wimmer, B.; Kirchner, R.

    1981-01-01

    Spontaneous perforation of the gallbladder is one complication of cholelithiasis. There is a greater occurence of free perforation in the peritoneal cavity with bilary pertonitis, followed by the perforation into the stomach, small intestine and colon. A single case of the nowadays rare spontaneous perforation in and through the abdominal wall will be reported. Spontaneous gallbladder perforation appears nearly asymptomatic in its clinical course because of absent biliary peritonitis. (orig.) [de

  18. Analysis of the Spontaneous Abortion in Chinese Married Women

    Institute of Scientific and Technical Information of China (English)

    高尔生; 邓新清; 何更生; 方可娟; 唐威; 楼超华

    1994-01-01

    The spontaneous abortion is a common type of pregnant outcomes. The spontaneous abortion rate can be used to indicate the women's fecundity and the level of the reproductive health. It is also a sensitive indicator for determing the social, economic, and health status and prenatal care. To explore the preventive method for spontaneous abortion and improve women's health level, it is important to evaluate the status of spontaneous abortion and to determine the factors affecting

  19. Peritonitis - spontaneous bacterial

    Science.gov (United States)

    Spontaneous bacterial peritonitis (SBP); Ascites - peritonitis; Cirrhosis - peritonitis ... who are on peritoneal dialysis for kidney failure. Peritonitis may have other causes . These include infection from ...

  20. 46 CFR 28.820 - Fire pumps, fire mains, fire hydrants, and fire hoses.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Fire pumps, fire mains, fire hydrants, and fire hoses... REQUIREMENTS FOR COMMERCIAL FISHING INDUSTRY VESSELS Aleutian Trade Act Vessels § 28.820 Fire pumps, fire mains, fire hydrants, and fire hoses. (a) Each vessel must be equipped with a self-priming, power driven fire...

  1. Spontaneous emission by moving atoms

    International Nuclear Information System (INIS)

    Meystre, P.; Wilkens, M.

    1994-01-01

    It is well known that spontaneous emission is not an intrinsic atomic property, but rather results from the coupling of the atom to the vacuum modes of the electromagnetic field. As such, it can be modified by tailoring the electromagnetic environment into which the atom can radiate. This was already realized by Purcell, who noted that the spontaneous emission rate can be enhanced if the atom placed inside a cavity is resonant with one of the cavity is resonant with one of the cavity modes, and by Kleppner, who discussed the opposite case of inhibited spontaneous emission. It has also been recognized that spontaneous emission need not be an irreversible process. Indeed, a system consisting of a single atom coupled to a single mode of the electromagnetic field undergoes a periodic exchange of excitation between the atom and the field. This periodic exchange remains dominant as long as the strength of the coupling between the atom and a cavity mode is itself dominant. 23 refs., 6 figs

  2. Mitigating Satellite-Based Fire Sampling Limitations in Deriving Biomass Burning Emission Rates: Application to WRF-Chem Model Over the Northern sub-Saharan African Region

    Science.gov (United States)

    Wang, Jun; Yue, Yun; Wang, Yi; Ichoku, Charles; Ellison, Luke; Zeng, Jing

    2018-01-01

    Largely used in several independent estimates of fire emissions, fire products based on MODIS sensors aboard the Terra and Aqua polar-orbiting satellites have a number of inherent limitations, including (a) inability to detect fires below clouds, (b) significant decrease of detection sensitivity at the edge of scan where pixel sizes are much larger than at nadir, and (c) gaps between adjacent swaths in tropical regions. To remedy these limitations, an empirical method is developed here and applied to correct fire emission estimates based on MODIS pixel level fire radiative power measurements and emission coefficients from the Fire Energetics and Emissions Research (FEER) biomass burning emission inventory. The analysis was performed for January 2010 over the northern sub-Saharan African region. Simulations from WRF-Chem model using original and adjusted emissions are compared with the aerosol optical depth (AOD) products from MODIS and AERONET as well as aerosol vertical profile from CALIOP data. The comparison confirmed an 30-50% improvement in the model simulation performance (in terms of correlation, bias, and spatial pattern of AOD with respect to observations) by the adjusted emissions that not only increases the original emission amount by a factor of two but also results in the spatially continuous estimates of instantaneous fire emissions at daily time scales. Such improvement cannot be achieved by simply scaling the original emission across the study domain. Even with this improvement, a factor of two underestimations still exists in the modeled AOD, which is within the current global fire emissions uncertainty envelope.

  3. Wildland fire limits subsequent fire occurrence

    Science.gov (United States)

    Sean A. Parks; Carol Miller; Lisa M. Holsinger; Scott Baggett; Benjamin J. Bird

    2016-01-01

    Several aspects of wildland fire are moderated by site- and landscape-level vegetation changes caused by previous fire, thereby creating a dynamic where one fire exerts a regulatory control on subsequent fire. For example, wildland fire has been shown to regulate the size and severity of subsequent fire. However, wildland fire has the potential to influence...

  4. Intracellular Methamphetamine Prevents the Dopamine-induced Enhancement of Neuronal Firing*

    Science.gov (United States)

    Saha, Kaustuv; Sambo, Danielle; Richardson, Ben D.; Lin, Landon M.; Butler, Brittany; Villarroel, Laura; Khoshbouei, Habibeh

    2014-01-01

    The dysregulation of the dopaminergic system is implicated in multiple neurological and neuropsychiatric disorders such as Parkinson disease and drug addiction. The primary target of psychostimulants such as amphetamine and methamphetamine is the dopamine transporter (DAT), the major regulator of extracellular dopamine levels in the brain. However, the behavioral and neurophysiological correlates of methamphetamine and amphetamine administration are unique from one another, thereby suggesting these two compounds impact dopaminergic neurotransmission differentially. We further examined the unique mechanisms by which amphetamine and methamphetamine regulate DAT function and dopamine neurotransmission; in the present study we examined the impact of extracellular and intracellular amphetamine and methamphetamine on the spontaneous firing of cultured midbrain dopaminergic neurons and isolated DAT-mediated current. In dopaminergic neurons the spontaneous firing rate was enhanced by extracellular application of amphetamine > dopamine > methamphetamine and was DAT-dependent. Amphetamine > methamphetamine similarly enhanced DAT-mediated inward current, which was sensitive to isosmotic substitution of Na+ or Cl− ion. Although isosmotic substitution of extracellular Na+ ions blocked amphetamine and methamphetamine-induced DAT-mediated inward current similarly, the removal of extracellular Cl− ions preferentially blocked amphetamine-induced inward current. The intracellular application of methamphetamine, but not amphetamine, prevented the dopamine-induced increase in the spontaneous firing of dopaminergic neurons and the corresponding DAT-mediated inward current. The results reveal a new mechanism for methamphetamine-induced dysregulation of dopaminergic neurons. PMID:24962577

  5. IMPROVEMENT OF FOREST FIRE DETECTION ALGORITHM USING BRIGHTNESS TEMPERATURE LAPSE RATE CORRECTION IN HIMAWARI-8 IR CHANNELS: APPLICATION TO THE 6 MAY 2017 SAMCHEOK CITY, KOREA

    Directory of Open Access Journals (Sweden)

    S. H. Park

    2018-04-01

    Full Text Available Forest fires are a major natural disaster that destroys a forest area and a natural environment. In order to minimize the damage caused by the forest fire, it is necessary to know the location and the time of day and continuous monitoring is required until fire is fully put out. We have tried to improve the forest fire detection algorithm by using a method to reduce the variability of surrounding pixels. We focused that forest areas of East Asia, part of the Himawari-8 AHI coverage, are mostly located in mountainous areas. The proposed method was applied to the forest fire detection in Samcheok city, Korea on May 6 to 10, 2017.

  6. Fire Behavior System for the Full Range of Fire Management Needs

    Science.gov (United States)

    Richard C. Rothermel; Patricia L. Andrews

    1987-01-01

    An "integrated fire behavior/fire danger rating system" should be "seamless" to avoid requiring choices among alternate, independent systems. Descriptions of fuel moisture, fuels, and fire behavior should be standardized, permitting information to flow easily through the spectrum of fire management needs. The level of resolution depends on the...

  7. Noise activated bistable sensor based on chaotic system with output defined by temporal coding and firing rate.

    Science.gov (United States)

    Korneta, Wojciech; Gomes, Iacyel

    2017-11-01

    Traditional bistable sensors use external bias signal to drive its response between states and their detection strategy is based on the output power spectral density or the residence time difference (RTD) in two sensor states. Recently, the noise activated nonlinear dynamic sensors driven only by noise based on RTD technique have been proposed. Here, we present experimental results of dc voltage measurements by noise-driven bistable sensor based on electronic Chua's circuit operating in a chaotic regime where two single scroll attractors coexist. The output of the sensor is quantified by the proportion of the time the sensor stays in one state to the total observation time and by the spike-count rate with spikes defined by crossings between attractors. The relationship between the stimuli and particular observable for different noise intensities is obtained, the usefulness of each coding scheme is discussed, and the optimal noise intensity for detection is indicated. It is shown that the obtained relationship is the same for any observation time when population coding is used. The optimal time window for both detection and the number of units in population coding is found. Our results may be useful for analyses and understanding of the neural activity and in designing bistable storage elements at length scales where thermal fluctuations drastically increase and the effect of noise must be taken into consideration.

  8. Spontaneous intracranial hypotension.

    LENUS (Irish Health Repository)

    Fullam, L

    2012-01-31

    INTRODUCTION: Spontaneous\\/primary intracranial hypotension is characterised by orthostatic headache and is associated with characteristic magnetic resonance imaging findings. CASE REPORT: We present a case report of a patient with typical symptoms and classical radiological images. DISCUSSION: Spontaneous intracranial hypotension is an under-recognised cause of headache and can be diagnosed by history of typical orthostatic headache and findings on MRI brain.

  9. Spontaneous and Evoked Activity from Murine Ventral Horn Cultures on Microelectrode Arrays

    Directory of Open Access Journals (Sweden)

    Bryan J. Black

    2017-09-01

    Full Text Available Motor neurons are the site of action for several neurological disorders and paralytic toxins, with cell bodies located in the ventral horn (VH of the spinal cord along with interneurons and support cells. Microelectrode arrays (MEAs have emerged as a high content assay platform for mechanistic studies and drug discovery. Here, we explored the spontaneous and evoked electrical activity of VH cultures derived from embryonic mouse spinal cord on multi-well plates of MEAs. Primary VH cultures from embryonic day 15–16 mice were characterized by expression of choline acetyltransferase (ChAT by immunocytochemistry. Well resolved, all-or-nothing spontaneous spikes with profiles consistent with extracellular action potentials were observed after 3 days in vitro, persisting with consistent firing rates until at least day in vitro 19. The majority of the spontaneous activity consisted of tonic firing interspersed with coordinated bursting across the network. After 5 days in vitro, spike activity was readily evoked by voltage pulses where a minimum amplitude and duration required for excitation was 300 mV and 100 μs/phase, respectively. We characterized the sensitivity of spontaneous and evoked activity to a host of pharmacological agents including AP5, CNQX, strychnine, ω-agatoxin IVA, and botulinum neurotoxin serotype A (BoNT/A. These experiments revealed sensitivity of the cultured VH to both agonist and antagonist compounds in a manner consistent with mature tissue derived from slices. In the case of BoNT/A, we also demonstrated intoxication persistence over an 18-day period, followed by partial intoxication recovery induced by N- and P/Q-type calcium channel agonist GV-58. In total, our findings suggest that VH cultures on multi-well MEA plates may represent a moderate throughput, high content assay for performing mechanistic studies and for screening potential therapeutics pertaining to paralytic toxins and neurological disorders.

  10. Computational Account of Spontaneous Activity as a Signature of Predictive Coding.

    Directory of Open Access Journals (Sweden)

    Veronika Koren

    2017-01-01

    Full Text Available Spontaneous activity is commonly observed in a variety of cortical states. Experimental evidence suggested that neural assemblies undergo slow oscillations with Up ad Down states even when the network is isolated from the rest of the brain. Here we show that these spontaneous events can be generated by the recurrent connections within the network and understood as signatures of neural circuits that are correcting their internal representation. A noiseless spiking neural network can represent its input signals most accurately when excitatory and inhibitory currents are as strong and as tightly balanced as possible. However, in the presence of realistic neural noise and synaptic delays, this may result in prohibitively large spike counts. An optimal working regime can be found by considering terms that control firing rates in the objective function from which the network is derived and then minimizing simultaneously the coding error and the cost of neural activity. In biological terms, this is equivalent to tuning neural thresholds and after-spike hyperpolarization. In suboptimal working regimes, we observe spontaneous activity even in the absence of feed-forward inputs. In an all-to-all randomly connected network, the entire population is involved in Up states. In spatially organized networks with local connectivity, Up states spread through local connections between neurons of similar selectivity and take the form of a traveling wave. Up states are observed for a wide range of parameters and have similar statistical properties in both active and quiescent state. In the optimal working regime, Up states are vanishing, leaving place to asynchronous activity, suggesting that this working regime is a signature of maximally efficient coding. Although they result in a massive increase in the firing activity, the read-out of spontaneous Up states is in fact orthogonal to the stimulus representation, therefore interfering minimally with the network

  11. Characterization of potential fire regimes: applying landscape ecology to fire management in Mexico

    Science.gov (United States)

    Jardel, E.; Alvarado, E.; Perez-Salicrup, D.; Morfín-Rios, J.

    2013-05-01

    Knowledge and understanding of fire regimes is fundamental to design sound fire management practices. The high ecosystem diversity of Mexico offers a great challenge to characterize the fire regime variation at the landscape level. A conceptual model was developed considering the main factors controlling fire regimes: climate and vegetation cover. We classified landscape units combining bioclimatic zones from the Holdridge life-zone system and actual vegetation cover. Since bioclimatic conditions control primary productivity and biomass accumulation (potential fuel), each landscape unit was considered as a fuel bed with a particular fire intensity and behavior potential. Climate is also a determinant factor of post-fire recovery rates of fuel beds, and climate seasonality (length of the dry and wet seasons) influences fire probability (available fuel and ignition efficiency). These two factors influence potential fire frequency. Potential fire severity can be inferred from fire frequency, fire intensity and behavior, and vegetation composition and structure. Based in the conceptual model, an exhaustive literature review and expert opinion, we developed rules to assign a potential fire regime (PFR) defined by frequency, intensity and severity (i.e. fire regime) to each bioclimatic-vegetation landscape unit. Three groups and eight types of potential fire regimes were identified. In Group A are fire-prone ecosystems with frequent low severity surface fires in grasslands (PFR type I) or forests with long dry season (II) and infrequent high-severity fires in chaparral (III), wet temperate forests (IV, fire restricted by humidity), and dry temperate forests (V, fire restricted by fuel recovery rate). Group B includes fire-reluctant ecosystems with very infrequent or occasional mixed severity surface fires limited by moisture in tropical rain forests (VI) or fuel availability in seasonally dry tropical forests (VII). Group C and PFR VIII include fire-free environments

  12. How fire history, fire suppression practices and climate change affect wildfire regimes in Mediterranean landscapes.

    Directory of Open Access Journals (Sweden)

    Lluís Brotons

    Full Text Available Available data show that future changes in global change drivers may lead to an increasing impact of fires on terrestrial ecosystems worldwide. Yet, fire regime changes in highly humanised fire-prone regions are difficult to predict because fire effects may be heavily mediated by human activities We investigated the role of fire suppression strategies in synergy with climate change on the resulting fire regimes in Catalonia (north-eastern Spain. We used a spatially-explicit fire-succession model at the landscape level to test whether the use of different firefighting opportunities related to observed reductions in fire spread rates and effective fire sizes, and hence changes in the fire regime. We calibrated this model with data from a period with weak firefighting and later assess the potential for suppression strategies to modify fire regimes expected under different levels of climate change. When comparing simulations with observed fire statistics from an eleven-year period with firefighting strategies in place, our results showed that, at least in two of the three sub-regions analysed, the observed fire regime could not be reproduced unless taking into account the effects of fire suppression. Fire regime descriptors were highly dependent on climate change scenarios, with a general trend, under baseline scenarios without fire suppression, to large-scale increases in area burnt. Fire suppression strategies had a strong capacity to compensate for climate change effects. However, strong active fire suppression was necessary to accomplish such compensation, while more opportunistic fire suppression strategies derived from recent fire history only had a variable, but generally weak, potential for compensation of enhanced fire impacts under climate change. The concept of fire regime in the Mediterranean is probably better interpreted as a highly dynamic process in which the main determinants of fire are rapidly modified by changes in landscape

  13. How fire history, fire suppression practices and climate change affect wildfire regimes in Mediterranean landscapes.

    Science.gov (United States)

    Brotons, Lluís; Aquilué, Núria; de Cáceres, Miquel; Fortin, Marie-Josée; Fall, Andrew

    2013-01-01

    Available data show that future changes in global change drivers may lead to an increasing impact of fires on terrestrial ecosystems worldwide. Yet, fire regime changes in highly humanised fire-prone regions are difficult to predict because fire effects may be heavily mediated by human activities We investigated the role of fire suppression strategies in synergy with climate change on the resulting fire regimes in Catalonia (north-eastern Spain). We used a spatially-explicit fire-succession model at the landscape level to test whether the use of different firefighting opportunities related to observed reductions in fire spread rates and effective fire sizes, and hence changes in the fire regime. We calibrated this model with data from a period with weak firefighting and later assess the potential for suppression strategies to modify fire regimes expected under different levels of climate change. When comparing simulations with observed fire statistics from an eleven-year period with firefighting strategies in place, our results showed that, at least in two of the three sub-regions analysed, the observed fire regime could not be reproduced unless taking into account the effects of fire suppression. Fire regime descriptors were highly dependent on climate change scenarios, with a general trend, under baseline scenarios without fire suppression, to large-scale increases in area burnt. Fire suppression strategies had a strong capacity to compensate for climate change effects. However, strong active fire suppression was necessary to accomplish such compensation, while more opportunistic fire suppression strategies derived from recent fire history only had a variable, but generally weak, potential for compensation of enhanced fire impacts under climate change. The concept of fire regime in the Mediterranean is probably better interpreted as a highly dynamic process in which the main determinants of fire are rapidly modified by changes in landscape, climate and

  14. How Fire History, Fire Suppression Practices and Climate Change Affect Wildfire Regimes in Mediterranean Landscapes

    Science.gov (United States)

    Brotons, Lluís; Aquilué, Núria; de Cáceres, Miquel; Fortin, Marie-Josée; Fall, Andrew

    2013-01-01

    Available data show that future changes in global change drivers may lead to an increasing impact of fires on terrestrial ecosystems worldwide. Yet, fire regime changes in highly humanised fire-prone regions are difficult to predict because fire effects may be heavily mediated by human activities We investigated the role of fire suppression strategies in synergy with climate change on the resulting fire regimes in Catalonia (north-eastern Spain). We used a spatially-explicit fire-succession model at the landscape level to test whether the use of different firefighting opportunities related to observed reductions in fire spread rates and effective fire sizes, and hence changes in the fire regime. We calibrated this model with data from a period with weak firefighting and later assess the potential for suppression strategies to modify fire regimes expected under different levels of climate change. When comparing simulations with observed fire statistics from an eleven-year period with firefighting strategies in place, our results showed that, at least in two of the three sub-regions analysed, the observed fire regime could not be reproduced unless taking into account the effects of fire suppression. Fire regime descriptors were highly dependent on climate change scenarios, with a general trend, under baseline scenarios without fire suppression, to large-scale increases in area burnt. Fire suppression strategies had a strong capacity to compensate for climate change effects. However, strong active fire suppression was necessary to accomplish such compensation, while more opportunistic fire suppression strategies derived from recent fire history only had a variable, but generally weak, potential for compensation of enhanced fire impacts under climate change. The concept of fire regime in the Mediterranean is probably better interpreted as a highly dynamic process in which the main determinants of fire are rapidly modified by changes in landscape, climate and

  15. Spontaneous Electrical Activity in the Nervous System and its ...

    African Journals Online (AJOL)

    The present study was carried out to examine the effects of biogenic amines on the spontaneous electrical activity of the nervous system in the silkworm Bombyx mori. The activity recorded from different segments of the ventral nerve cord differed in the frequency and number of spike categories firing. The activity was highest ...

  16. A FIRE-ACE/SHEBA Case Study of Mixed-Phase Arctic Boundary Layer Clouds: Entrainment Rate Limitations on Rapid Primary Ice Nucleation Processes

    Science.gov (United States)

    Fridlin, Ann; vanDiedenhoven, Bastiaan; Ackerman, Andrew S.; Avramov, Alexander; Mrowiec, Agnieszka; Morrison, Hugh; Zuidema, Paquita; Shupe, Matthew D.

    2012-01-01

    Observations of long-lived mixed-phase Arctic boundary layer clouds on 7 May 1998 during the First International Satellite Cloud Climatology Project (ISCCP) Regional Experiment (FIRE)Arctic Cloud Experiment (ACE)Surface Heat Budget of the Arctic Ocean (SHEBA) campaign provide a unique opportunity to test understanding of cloud ice formation. Under the microphysically simple conditions observed (apparently negligible ice aggregation, sublimation, and multiplication), the only expected source of new ice crystals is activation of heterogeneous ice nuclei (IN) and the only sink is sedimentation. Large-eddy simulations with size-resolved microphysics are initialized with IN number concentration N(sub IN) measured above cloud top, but details of IN activation behavior are unknown. If activated rapidly (in deposition, condensation, or immersion modes), as commonly assumed, IN are depleted from the well-mixed boundary layer within minutes. Quasi-equilibrium ice number concentration N(sub i) is then limited to a small fraction of overlying N(sub IN) that is determined by the cloud-top entrainment rate w(sub e) divided by the number-weighted ice fall speed at the surface v(sub f). Because w(sub c) 10 cm/s, N(sub i)/N(sub IN)<< 1. Such conditions may be common for this cloud type, which has implications for modeling IN diagnostically, interpreting measurements, and quantifying sensitivity to increasing N(sub IN) (when w(sub e)/v(sub f)< 1, entrainment rate limitations serve to buffer cloud system response). To reproduce observed ice crystal size distributions and cloud radar reflectivities with rapidly consumed IN in this case, the measured above-cloud N(sub IN) must be multiplied by approximately 30. However, results are sensitive to assumed ice crystal properties not constrained by measurements. In addition, simulations do not reproduce the pronounced mesoscale heterogeneity in radar reflectivity that is observed.

  17. Spontaneous regression of metastatic Merkel cell carcinoma.

    LENUS (Irish Health Repository)

    Hassan, S J

    2010-01-01

    Merkel cell carcinoma is a rare aggressive neuroendocrine carcinoma of the skin predominantly affecting elderly Caucasians. It has a high rate of local recurrence and regional lymph node metastases. It is associated with a poor prognosis. Complete spontaneous regression of Merkel cell carcinoma has been reported but is a poorly understood phenomenon. Here we present a case of complete spontaneous regression of metastatic Merkel cell carcinoma demonstrating a markedly different pattern of events from those previously published.

  18. On fire

    DEFF Research Database (Denmark)

    Hansen, Helle Rabøl

    The title of this paper: “On fire”, refers to two (maybe three) aspects: firstly as a metaphor of having engagement in a community of practice according to Lave & Wenger (1991), and secondly it refers to the concrete element “fire” in the work of the fire fighters – and thirdly fire as a signifier...

  19. Fire Power

    Science.gov (United States)

    Denker, Deb; West, Lee

    2009-01-01

    For education administrators, campus fires are not only a distressing loss, but also a stark reminder that a campus faces risks that require special vigilance. In many ways, campuses resemble small communities, with areas for living, working and relaxing. A residence hall fire may raise the specter of careless youth, often with the complication of…

  20. Management of intractable spontaneous epistaxis

    Science.gov (United States)

    Rudmik, Luke

    2012-01-01

    Background: Epistaxis is a common otolaryngology emergency and is often controlled with first-line interventions such as cautery, hemostatic agents, or anterior nasal packing. A subset of patients will continue to bleed and require more aggressive therapy. Methods: Intractable spontaneous epistaxis was traditionally managed with posterior nasal packing and prolonged hospital admission. In an effort to reduce patient morbidity and shorten hospital stay, surgical and endovascular techniques have gained popularity. A literature review was conducted. Results: Transnasal endoscopic sphenopalatine artery ligation and arterial embolization provide excellent control rates but the decision to choose one over the other can be challenging. The role of transnasal endoscopic anterior ethmoid artery ligation is unclear but may be considered in certain cases when bleeding localizes to the ethmoid region. Conclusion: This article will focus on the management of intractable spontaneous epistaxis and discuss the role of endoscopic arterial ligation and embolization as it pertains to this challenging clinical scenario. PMID:22391084

  1. 46 CFR 28.315 - Fire pumps, fire mains, fire hydrants, and fire hoses.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Fire pumps, fire mains, fire hydrants, and fire hoses... After September 15, 1991, and That Operate With More Than 16 Individuals on Board § 28.315 Fire pumps, fire mains, fire hydrants, and fire hoses. (a) Each vessel 36 feet (11.8 meters) or more in length must...

  2. Forest-fire models

    Science.gov (United States)

    Haiganoush Preisler; Alan Ager

    2013-01-01

    For applied mathematicians forest fire models refer mainly to a non-linear dynamic system often used to simulate spread of fire. For forest managers forest fire models may pertain to any of the three phases of fire management: prefire planning (fire risk models), fire suppression (fire behavior models), and postfire evaluation (fire effects and economic models). In...

  3. Spontaneous pneumothorax in diffuse cystic lung diseases.

    Science.gov (United States)

    Cooley, Joseph; Lee, Yun Chor Gary; Gupta, Nishant

    2017-07-01

    Diffuse cystic lung diseases (DCLDs) are a heterogeneous group of disorders with varying pathophysiologic mechanisms that are characterized by the presence of air-filled lung cysts. These cysts are prone to rupture, leading to the development of recurrent spontaneous pneumothoraces. In this article, we review the epidemiology, clinical features, and management DCLD-associated spontaneous pneumothorax, with a focus on lymphangioleiomyomatosis, Birt-Hogg-Dubé syndrome, and pulmonary Langerhans cell histiocytosis. DCLDs are responsible for approximately 10% of apparent primary spontaneous pneumothoraces. Computed tomography screening for DCLDs (Birt-Hogg-Dubé syndrome, lymphangioleiomyomatosis, and pulmonary Langerhans cell histiocytosis) following the first spontaneous pneumothorax has recently been shown to be cost-effective and can help facilitate early diagnosis of the underlying disorders. Patients with DCLD-associated spontaneous pneumothorax have a very high rate of recurrence, and thus pleurodesis should be considered following the first episode of spontaneous pneumothorax in these patients, rather than waiting for a recurrent episode. Prior pleurodesis is not a contraindication to future lung transplant. Although DCLDs are uncommon, spontaneous pneumothorax is often the sentinel event that provides an opportunity for diagnosis. By understanding the burden and implications of pneumothoraces in DCLDs, clinicians can facilitate early diagnosis and appropriate management of the underlying disorders.

  4. Firing-rate based network modeling of the dLGN circuit: Effects of cortical feedback on spatiotemporal response properties of relay cells.

    Science.gov (United States)

    Mobarhan, Milad Hobbi; Halnes, Geir; Martínez-Cañada, Pablo; Hafting, Torkel; Fyhn, Marianne; Einevoll, Gaute T

    2018-05-01

    Visually evoked signals in the retina pass through the dorsal geniculate nucleus (dLGN) on the way to the visual cortex. This is however not a simple feedforward flow of information: there is a significant feedback from cortical cells back to both relay cells and interneurons in the dLGN. Despite four decades of experimental and theoretical studies, the functional role of this feedback is still debated. Here we use a firing-rate model, the extended difference-of-Gaussians (eDOG) model, to explore cortical feedback effects on visual responses of dLGN relay cells. For this model the responses are found by direct evaluation of two- or three-dimensional integrals allowing for fast and comprehensive studies of putative effects of different candidate organizations of the cortical feedback. Our analysis identifies a special mixed configuration of excitatory and inhibitory cortical feedback which seems to best account for available experimental data. This configuration consists of (i) a slow (long-delay) and spatially widespread inhibitory feedback, combined with (ii) a fast (short-delayed) and spatially narrow excitatory feedback, where (iii) the excitatory/inhibitory ON-ON connections are accompanied respectively by inhibitory/excitatory OFF-ON connections, i.e. following a phase-reversed arrangement. The recent development of optogenetic and pharmacogenetic methods has provided new tools for more precise manipulation and investigation of the thalamocortical circuit, in particular for mice. Such data will expectedly allow the eDOG model to be better constrained by data from specific animal model systems than has been possible until now for cat. We have therefore made the Python tool pyLGN which allows for easy adaptation of the eDOG model to new situations.

  5. Multilayer perceptron classification of unknown volatile chemicals from the firing rates of insect olfactory sensory neurons and its application to biosensor design.

    Science.gov (United States)

    Bachtiar, Luqman R; Unsworth, Charles P; Newcomb, Richard D; Crampin, Edmund J

    2013-01-01

    In this letter, we use the firing rates from an array of olfactory sensory neurons (OSNs) of the fruit fly, Drosophila melanogaster, to train an artificial neural network (ANN) to distinguish different chemical classes of volatile odorants. Bootstrapping is implemented for the optimized networks, providing an accurate estimate of a network's predicted values. Initially a simple linear predictor was used to assess the complexity of the data and was found to provide low prediction performance. A nonlinear ANN in the form of a single multilayer perceptron (MLP) was also used, providing a significant increase in prediction performance. The effect of the number of hidden layers and hidden neurons of the MLP was investigated and found to be effective in enhancing network performance with both a single and a double hidden layer investigated separately. A hybrid array of MLPs was investigated and compared against the single MLP architecture. The hybrid MLPs were found to classify all vectors of the validation set, presenting the highest degree of prediction accuracy. Adjustment of the number of hidden neurons was investigated, providing further performance gain. In addition, noise injection was investigated, proving successful for certain network designs. It was found that the best-performing MLP was that of the double-hidden-layer hybrid MLP network without the use of noise injection. Furthermore, the level of performance was examined when different numbers of OSNs used were varied from the maximum of 24 to only 5 OSNs. Finally, the ideal OSNs were identified that optimized network performance. The results obtained from this study provide strong evidence of the usefulness of ANNs in the field of olfaction for the future realization of a signal processing back end for an artificial olfactory biosensor.

  6. Effect of natural fiber types and sodium silicate coated on natural fiber mat/PLA composites: Tensile properties and rate of fire propagation

    Science.gov (United States)

    Thongpin, C.; Srimuk, J.; hipkam, N.; Wachirapong, P.

    2015-07-01

    In this study, 3 types of natural fibres, i.e. jute, sisal and abaca, were plain weaved to fibre mat. Before weaving, the fibres were treated with 5% NaOH to remove hemi cellulose and lignin. The weaving was performed by hand using square wooden block fit with nails for weaving using one and two types of natural fibres as weft and warp fibre to produce natural fibre mat. The fibre mat was also impregnated in sodium silicate solution extracted from rich husk ash. The pH of the solution was adjusted to pH 7 using H2SO4 before impregnation. After predetermined time, sodium silicate was gelled and deposited on the mat. The fabric mat and sodium silicate coated mat were then impregnated with PLA solution to produce prepreg. Dried pepreg was laminated with PLA sheet using compressing moulding machine to obtain natural fibre mat/PLA composite. The composite containing abaca aligned in longitudinal direction with respect to tension force enhanced Young's modulus more than 300%. Fibre mat composites with abaca aligned in longitudinal direction also showed tensile strength enhancement nearly 400% higher than neat PLA. After coating with sodium silicate, the tensile modulus of the composites was found slightly increased. The silicate coating was disadvantage on tensile strength of the composite due to the effect of sodium hydroxide solution that was used as solvent for silicate extraction from rice husk ash. However, sodium silicate could retard rate of fire propagation about 50%compare to neat PLA and about 10% reduction compared to fibre mat composites without sodium silicate coated fibre mat.

  7. Effect of natural fiber types and sodium silicate coated on natural fiber mat/PLA composites: Tensile properties and rate of fire propagation

    International Nuclear Information System (INIS)

    Thongpin, C; Srimuk, J; Hipkam, N; Wachirapong, P

    2015-01-01

    In this study, 3 types of natural fibres, i.e. jute, sisal and abaca, were plain weaved to fibre mat. Before weaving, the fibres were treated with 5% NaOH to remove hemi cellulose and lignin. The weaving was performed by hand using square wooden block fit with nails for weaving using one and two types of natural fibres as weft and warp fibre to produce natural fibre mat. The fibre mat was also impregnated in sodium silicate solution extracted from rich husk ash. The pH of the solution was adjusted to pH 7 using H 2 SO 4 before impregnation. After predetermined time, sodium silicate was gelled and deposited on the mat. The fabric mat and sodium silicate coated mat were then impregnated with PLA solution to produce prepreg. Dried pepreg was laminated with PLA sheet using compressing moulding machine to obtain natural fibre mat/PLA composite. The composite containing abaca aligned in longitudinal direction with respect to tension force enhanced Young's modulus more than 300%. Fibre mat composites with abaca aligned in longitudinal direction also showed tensile strength enhancement nearly 400% higher than neat PLA. After coating with sodium silicate, the tensile modulus of the composites was found slightly increased. The silicate coating was disadvantage on tensile strength of the composite due to the effect of sodium hydroxide solution that was used as solvent for silicate extraction from rice husk ash. However, sodium silicate could retard rate of fire propagation about 50%compare to neat PLA and about 10% reduction compared to fibre mat composites without sodium silicate coated fibre mat. (paper)

  8. Use of Landsat thermal imagery for dynamically monitoring spontaneous combustion of Datong Jurassic coalfields in China

    Science.gov (United States)

    Xue, Yongan; Liu, Jin; Li, Jun; Shang, Changsheng; Zhao, Jinling; Zhang, Mingmei

    2018-06-01

    It is highly helpful and necessary to investigate and monitor the status of coal seam. Fortunately, remote sensing has facilitated the identification and dynamical monitoring of spontaneous combustion for a large area coal mining area, especially using the time series remotely-sensed datasets. In this paper, Datong Jurassic coal mining area is used as the study area, China, and an exclusion method and a multiple-factor analysis method are jointly used to identify the spontaneous combustion, including land surface temperature (LST), burnt rocks, and land use and land cover change (LUCC). The LST is firstly retrieved using a single-window algorithm due to a thermal infrared band of Landsat-5 TM (Thematic Mapper). Burnt rocks is then extracted using a decision-tree classification method based on a high-resolution SPOT-5 image. The thermal anomaly areas are identified and refined by the spatial overlay analysis of the above affecting factors. Three-period maps of coal fire areas are obtained and dynamically analyzed in 2007, 2009 and 2010. The results show that a total of 12 coal fire areas have been identified, which account for more than 1% of the total area of the study area. In general, there is an increasing trend yearly and a total of 771,970 m2 is increased. The average annual increase is 257,320 m2, the average annual growth rate is 3.78%, and the dynamic degree is 11.29%.

  9. Radiologic findings of acute spontaneous subdural hematomas

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyun Jung; Bae, Won Kyong; Gyu, Cha Jang; Kim, Gun Woo; Cho, Won Su; Kim, Il Young; Lee, Kyung Suk [Soonchunhyang University, Chonan (Korea, Republic of). Chonan Hospital

    1998-03-01

    To evaluate the characteristic CT and cerebral angiographic findings in patients with acute spontaneous subdural hematomas and correlate these imaging findings with causes of bleeding and clinical outcome. Twenty-one patients with nontraumatic acute spontaneous subdural hematoma presenting during the last five years underwent CT scanning and cerebral angiography was performed in twelve. To determine the cause of bleedings, CT and angiographic findings were retrospectively analysed. Clinical history, laboratory and operative findings, and final clinical outcome were reviewed. Acute spontaneous subdural hematoma is a rare condition, and the mortality rate is high. In patients with acute spontaneous subdural hematoma, as seen on CT, associated subarachnoid or intracerebral hemorrhage is strongly indicative of intracerebral vascular abnormalities such as aneurysm and arteriovenous malformation, and cerebral angiography is necessary. To ensure proper treatment and thus markedly reduce mortality, the causes of bleedings should be prompty determined by means of cerebral angiography. (author). 20 refs., 1 tab., 4 figs.

  10. Spontaneous emission from active dielectric microstructures

    DEFF Research Database (Denmark)

    Søndergaard, Thomas; Tromborg, Bjarne

    2001-01-01

    and engineered due to the dependence of the emission rate on the location and polarisation of the emitters in the structure. This paper addresses the methods of quantum electrodynamics of dielectric media which enable calculation of the local rate of spontaneous emission in active microstructures....

  11. Fire behaviour - A preliminary study. | W.S.W. | African Journal of ...

    African Journals Online (AJOL)

    Fire behaviour - A preliminary study. ... be taken cognisance of in any future research on fire in relation to vegetation. Keywords: behaviour; botany; environmental conditions; fire; fire behaviour; fire ecology; fires; grass; grasses; management; rate of spread; recovery; south africa; vegetation; veld; veld management; yield ...

  12. Definition of spontaneous reconnection

    International Nuclear Information System (INIS)

    Schindler, K.

    1984-01-01

    The author discusses his view of driven versus spontaneous. There is a close link between ''spontaneous'' and ''instability.'' One of the prominent examples for instability is the thermal convection instability. Just to remind you, if you heat a fluid layer from below, it takes a certain Rayleigh number to make it unstable. Beyond the onset point you find qualitatively new features. That is called ''spontaneous,'' and this is a bit more than semantics. It's a new qualitative property that appears and it is spontaneous although we have an energy flux through the system. It's a misconception, to call this ''driven'' pointing at the energy flux through it. Of course, the convection would not exist without this energy flux. But what makes it ''spontaneous'' is that without any particular external signal, a new qualitative feature appears. And this is what is called an ''instability'' and ''spontaneous.'' From these considerations the author got a little reassured of what distinction should be made in the field of the magnetosphere. If we have a smooth energy transport into the magnetosphere and suddenly we have this qualitatively new feature (change of B-topology) coming up; then, using this terminology we don't have a choice other than calling this spontaneous or unstable, if you like. If we ''tell'' the system where it should make its neutral line and where it should make its plasmoids, then, it is driven. And this provides a very clear-cut observational distinction. The author emphasizes the difference he sees is a qualitative difference, not only a quantitative one

  13. Differences in the motor unit firing rates and amplitudes in relation to recruitment thresholds during submaximal contractions of the first dorsal interosseous between chronically resistance trained and physically active men.

    Science.gov (United States)

    Sterczala, Adam J; Miller, Jonathan D; Trevino, Michael A; Dimmick, Hannah L; Herda, Trent J

    2018-02-26

    Previous investigations report no changes in motor unit (MU) firing rates during submaximal contractions following resistance training. These investigations did not account for MU recruitment or examine firing rates as a function of recruitment threshold (REC).Therefore, MU recruitment and firing rates in chronically resistance trained (RT) and physically active controls (CON) were examined. Surface electromyography signals were collected from the first dorsal interosseous (FDI) during isometric muscle actions at 40% and 70% maximal voluntary contraction (MVC). For each MU, force at REC, mean firing rate (MFR) during the steady force, and MU action potential amplitude (MUAPAMP) were analyzed. For each individual and contraction, the MFRs were linearly regressed against REC, whereas, exponential models were applied to the MFR vs. MUAPAMP and MUAPAMP vs. REC relationships with the y-intercepts and slopes (linear) and A and B terms (exponential) calculated. For the 40% MVC, the RT group had less negative slopes (p=0.001) and lower y-intercepts (p=0.006) of the MFR vs. REC relationships and lower B terms (p=0.011) of the MUAPAMP vs. REC relationships. There were no differences in either relationship between groups for the 70% MVC. During the 40% MVC, the RT had a smaller range of MFRs and MUAPAMPS in comparison to the CON, likely due to reduced MU recruitment. The RT had lower MFRs and recruitment during the 40% MVC that may indicate a leftward shift in the force-frequency relationship, and thus require less excitation to the motoneuron pool to match the same relative force.

  14. A method for ensemble wildland fire simulation

    Science.gov (United States)

    Mark A. Finney; Isaac C. Grenfell; Charles W. McHugh; Robert C. Seli; Diane Trethewey; Richard D. Stratton; Stuart Brittain

    2011-01-01

    An ensemble simulation system that accounts for uncertainty in long-range weather conditions and two-dimensional wildland fire spread is described. Fuel moisture is expressed based on the energy release component, a US fire danger rating index, and its variation throughout the fire season is modeled using time series analysis of historical weather data. This analysis...

  15. Fire behavior in Mediterranean shrub species (Maquis)

    African Journals Online (AJOL)

    STORAGESEVER

    2008-11-19

    Nov 19, 2008 ... 36°C. Of the fire behavior characteristics, rate of spread ranged from 0.38 to 7.35 m min-1, fuel ... Key words: Fire behavior, fuel biomass, Maquis, shrubland, Turkey. ...... Two rural/urban interface fires in the Wellington.

  16. Fire safety

    International Nuclear Information System (INIS)

    Keski-Rahkonen, O.; Bjoerkman, J.; Hostikka, S.; Mangs, J.; Huhtanen, R.; Palmen, H.; Salminen, A.; Turtola, A.

    1998-01-01

    According to experience and probabilistic risk assessments, fires present a significant hazard in a nuclear power plant. Fires may be initial events for accidents or affect safety systems planned to prevent accidents and to mitigate their consequences. The project consists of theoretical work, experiments and simulations aiming to increase the fire safety at nuclear power plants. The project has four target areas: (1) to produce validated models for numerical simulation programmes, (2) to produce new information on the behavior of equipment in case of fire, (3) to study applicability of new active fire protecting systems in nuclear power plants, and (4) to obtain quantitative knowledge of ignitions induced by important electric devices in nuclear power plants. These topics have been solved mainly experimentally, but modelling at different level is used to interpret experimental data, and to allow easy generalisation and engineering use of the obtained data. Numerical fire simulation has concentrated in comparison of CFD modelling of room fires, and fire spreading on cables on experimental data. So far the success has been good to fair. A simple analytical and numerical model has been developed for fire effluents spreading beyond the room of origin in mechanically strongly ventilated compartments. For behaviour of equipment in fire several full scale and scaled down calorimetric experiments were carried out on electronic cabinets, as well as on horizontal and vertical cable trays. These were carried out to supply material for CFD numerical simulation code validation. Several analytical models were developed and validated against obtained experimental results to allow quick calculations for PSA estimates as well as inter- and extrapolations to slightly different objects. Response times of different commercial fire detectors were determined for different types of smoke, especially emanating from smoldering and flaming cables to facilitate selection of proper detector

  17. Windscale fire

    International Nuclear Information System (INIS)

    Auxier, J.A.

    1986-01-01

    A graphite fire in the Windscale No. 1 reactor occurred during the period October 8-12, 1957. The Windscale reactors were located on a coastal plain in northwest England and were used to produce plutonium. A great wealth of information was gathered on the causes, handling, decontamination, and environmental effects of reactor accidents. Topics of discussion include: the cause of the fire; handling of the incident; radiation doses to the population; and radiation effects on the population

  18. Model of large pool fires

    Energy Technology Data Exchange (ETDEWEB)

    Fay, J.A. [Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)]. E-mail: jfay@mit.edu

    2006-08-21

    A two zone entrainment model of pool fires is proposed to depict the fluid flow and flame properties of the fire. Consisting of combustion and plume zones, it provides a consistent scheme for developing non-dimensional scaling parameters for correlating and extrapolating pool fire visible flame length, flame tilt, surface emissive power, and fuel evaporation rate. The model is extended to include grey gas thermal radiation from soot particles in the flame zone, accounting for emission and absorption in both optically thin and thick regions. A model of convective heat transfer from the combustion zone to the liquid fuel pool, and from a water substrate to cryogenic fuel pools spreading on water, provides evaporation rates for both adiabatic and non-adiabatic fires. The model is tested against field measurements of large scale pool fires, principally of LNG, and is generally in agreement with experimental values of all variables.

  19. Model of large pool fires

    International Nuclear Information System (INIS)

    Fay, J.A.

    2006-01-01

    A two zone entrainment model of pool fires is proposed to depict the fluid flow and flame properties of the fire. Consisting of combustion and plume zones, it provides a consistent scheme for developing non-dimensional scaling parameters for correlating and extrapolating pool fire visible flame length, flame tilt, surface emissive power, and fuel evaporation rate. The model is extended to include grey gas thermal radiation from soot particles in the flame zone, accounting for emission and absorption in both optically thin and thick regions. A model of convective heat transfer from the combustion zone to the liquid fuel pool, and from a water substrate to cryogenic fuel pools spreading on water, provides evaporation rates for both adiabatic and non-adiabatic fires. The model is tested against field measurements of large scale pool fires, principally of LNG, and is generally in agreement with experimental values of all variables

  20. Rate of Speed

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — Rate of spread was modeled using FlamMap, an interagency fire behavior mapping and analysis program that computes potential fire behavior characteristics. The tool...

  1. Case of spontaneous ventriculocisternostomy

    Energy Technology Data Exchange (ETDEWEB)

    Yamane, Kanji; Yoshimoto, Hisanori; Harada, Kiyoshi; Uozumi, Tohru [Hiroshima Univ. (Japan). School of Medicine; Kuwabara, Satoshi

    1983-05-01

    The authors experienced a case of spontaneous ventriculocisternostomy diagnosed by CT scan with metrizamide and Conray. Patient was 23-year-old male who had been in good health until one month before admission, when he began to have headache and tinnitus. He noticed bilateral visual acuity was decreased about one week before admission and vomiting appeared two days before admission. He was admitted to our hospital because of bilateral papilledema and remarkable hydrocephalus diagnosed by CT scan. On admission, no abnormal neurological signs except for bilateral papilledema were noted. Immediately, right ventricular drainage was performed. Pressure of the ventricle was over 300mmH/sub 2/O and CSF was clear. PVG and PEG disclosed an another cavity behind the third ventricle, which was communicated with the third ventricle, and occlusion of aqueduct of Sylvius. Metrizamide CT scan and Conray CT scan showed a communication between this cavity and quadrigeminal and supracerebellar cisterns. On these neuroradiological findings, the diagnosis of obstructive hydrocephalus due to benign aqueduct stenosis accompanied with spontaneous ventriculocisternostomy was obtained. Spontaneous ventriculocisternostomy was noticed to produce arrest of hydrocephalus, but with our case, spontaneous regression of such symptoms did not appeared. By surgical ventriculocisternostomy (method by Torkildsen, Dandy, or Scarff), arrest of hydrocephalus was seen in about 50 to 70 per cent, which was the same results as those of spontaneous ventriculocisternostomy. It is concluded that VP shunt or VA shunt is thought to be better treatment of obstructive hydrocephalus than the various kinds of surgical ventriculocisternostomy.

  2. Characterization of flame radiosity in shrubland fires

    Science.gov (United States)

    Miguel G. Cruz; Bret W. Butler; Domingos X. Viegas; Pedro Palheiro

    2011-01-01

    The present study is aimed at quantifying the flame radiosity vertical profile and gas temperature in moderate to high intensity spreading fires in shrubland fuels. We report on the results from 11 experimental fires conducted over a range of fire rate of spread and frontal fire intensity varying respectively between 0.04-0.35ms-1 and 468-14,973kWm-1. Flame radiosity,...

  3. Spontaneous oscillations in microfluidic networks

    Science.gov (United States)

    Case, Daniel; Angilella, Jean-Regis; Motter, Adilson

    2017-11-01

    Precisely controlling flows within microfluidic systems is often difficult which typically results in systems being heavily reliant on numerous external pumps and computers. Here, I present a simple microfluidic network that exhibits flow rate switching, bistablity, and spontaneous oscillations controlled by a single pressure. That is, by solely changing the driving pressure, it is possible to switch between an oscillating and steady flow state. Such functionality does not rely on external hardware and may even serve as an on-chip memory or timing mechanism. I use an analytic model and rigorous fluid dynamics simulations to show these results.

  4. Fire Protection Informational Exchange

    Science.gov (United States)

    2016-07-01

    durable and launderable. A summary of contractor lead efforts to achieve these goals was presented. 3.19 US Naval Air Systems Command The NAVAIR fire... contractors spoke next concerning their companies’ technologies for fuel fire mitigation. Randy Fontinakes from Meggitt summarized his company’s products...decomprHalon FUS~ ht Surgeon’a Manual, USN: 0 Mdentlry, rapid d.eC)mpt"tMion • moct.rate .ctfvtty, rapkl decomprualon c: 0 Ill 5 1000 +- ph~lo4oglcal

  5. Spontaneous tension haemopneumothorax.

    Science.gov (United States)

    Patterson, Benjamin Oliver; Itam, Sarah; Probst, Fey

    2008-10-31

    We present a patient with sudden onset progressive shortness of breath and no history of trauma, who rapidly became haemodynamically compromised with a pneumothorax and pleural effusion seen on chest radiograph. He was treated for spontaneous tension pneumothorax but this was soon revealed to be a tension haemopneumothorax. He underwent urgent thoracotomy after persistent bleeding to explore an apical vascular abnormality seen on CT scanning. To our knowledge this is the first such case reported.Aetiology and current approach to spontaneous haemothorax are discussed briefly.

  6. Spontaneous Atraumatic Mediastinal Hemorrhage

    Directory of Open Access Journals (Sweden)

    Morkos Iskander BSc, BMBS, MRCS, PGCertMedEd

    2013-04-01

    Full Text Available Spontaneous atraumatic mediastinal hematomas are rare. We present a case of a previously fit and well middle-aged lady who presented with acute breathlessness and an increasing neck swelling and spontaneous neck bruising. On plain chest radiograph, widening of the mediastinum was noted. The bruising was later confirmed to be secondary to mediastinal hematoma. This life-threatening diagnostic conundrum was managed conservatively with a multidisciplinary team approach involving upper gastrointestinal and thoracic surgeons, gastroenterologists, radiologists, intensivists, and hematologists along with a variety of diagnostic modalities. A review of literature is also presented to help surgeons manage such challenging and complicated cases.

  7. Spontaneous tension haemopneumothorax

    Directory of Open Access Journals (Sweden)

    Itam Sarah

    2008-10-01

    Full Text Available Abstract We present a patient with sudden onset progressive shortness of breath and no history of trauma, who rapidly became haemodynamically compromised with a pneumothorax and pleural effusion seen on chest radiograph. He was treated for spontaneous tension pneumothorax but this was soon revealed to be a tension haemopneumothorax. He underwent urgent thoracotomy after persistent bleeding to explore an apical vascular abnormality seen on CT scanning. To our knowledge this is the first such case reported. Aetiology and current approach to spontaneous haemothorax are discussed briefly.

  8. Fire-safety engineering and performance-based codes

    DEFF Research Database (Denmark)

    Sørensen, Lars Schiøtt

    project administrators, etc. The book deals with the following topics: • Historical presentation on the subject of fire • Legislation and building project administration • European fire standardization • Passive and active fire protection • Performance-based Codes • Fire-safety Engineering • Fundamental......Fire-safety Engineering is written as a textbook for Engineering students at universities and other institutions of higher education that teach in the area of fire. The book can also be used as a work of reference for consulting engineers, Building product manufacturers, contractors, building...... thermodynamics • Heat exchange during the fire process • Skin burns • Burning rate, energy release rate and design fires • Proposal to Risk-based design fires • Proposal to a Fire scale • Material ignition and flame spread • Fire dynamics in buildings • Combustion products and toxic gases • Smoke inhalation...

  9. Spontaneous rib fractures.

    Science.gov (United States)

    Katrancioglu, Ozgur; Akkas, Yucel; Arslan, Sulhattin; Sahin, Ekber

    2015-07-01

    Other than trauma, rib fracture can occur spontaneously due to a severe cough or sneeze. In this study, patients with spontaneous rib fractures were analyzed according to age, sex, underlying pathology, treatment, and complications. Twelve patients who presented between February 2009 and February 2011 with spontaneous rib fracture were reviewed retrospectively. The patients' data were evaluated according to anamnesis, physical examination, and chest radiographs. The ages of the patients ranged from 34 to 77 years (mean 55.91 ± 12.20 years), and 7 (58.4%) were male. All patients had severe cough and chest pain. The fractures were most frequently between 4th and 9th ribs; multiple rib fractures were detected in 5 (41.7%) patients. Eight (66.7%) patients had chronic obstructive pulmonary disease, 2 (16.7%) had bronchial asthma, and 2 (16.7%) had osteoporosis. Bone densitometry revealed a high risk of bone fracture in all patients. Patients with chronic obstructive pulmonary disease or bronchial asthma had been treated with high-dose steroids for over a year. Spontaneous rib fracture due to severe cough may occur in patients with osteoporosis, chronic obstructive pulmonary disease, or bronchial asthma, receiving long-term steroid therapy. If these patients have severe chest pain, chest radiography should be performed to check for bone lesions. © The Author(s) 2015.

  10. [Spontaneous bacterial peritonitis].

    Science.gov (United States)

    Velkey, Bálint; Vitális, Eszter; Vitális, Zsuzsanna

    2017-01-01

    Spontaneous bacterial peritonitis occurs most commonly in cirrhotic patients with ascites. Pathogens get into the circulation by intestinal translocation and colonize in peritoneal fluid. Diagnosis of spontaneous bacterial peritonitis is based on elevated polymorphonuclear leukocyte count in the ascites (>0,25 G/L). Ascites culture is often negative but aids to get information about antibiotic sensitivity in positive cases. Treatment in stable patient can be intravenous then orally administrated ciprofloxacin or amoxicillin/clavulanic acid, while in severe cases intravenous III. generation cephalosporin. Nosocomial spontaneous bacterial peritonitis often caused by Gram-positive bacteria and multi-resistant pathogens can also be expected thus carbapenem should be the choice of the empiric treatment. Antibiotic prophylaxis should be considered. Norfloxacin is used most commonly, but changes are expected due to increase in quinolone resistance. As a primary prophylaxis, a short-term antibiotic treatment is recommended after gastrointestinal bleeding for 5 days, while long-term prophylaxis is for patients with low ascites protein, and advanced disease (400 mg/day). Secondary prophylaxis is recommended for all patients recovered from spontaneous bacterial peritonitis. Due to increasing antibiotic use of antibiotics prophylaxis is debated to some degree. Orv. Hetil., 2017, 158(2), 50-57.

  11. Spontaneously emerging cortical representations of visual attributes

    Science.gov (United States)

    Kenet, Tal; Bibitchkov, Dmitri; Tsodyks, Misha; Grinvald, Amiram; Arieli, Amos

    2003-10-01

    Spontaneous cortical activity-ongoing activity in the absence of intentional sensory input-has been studied extensively, using methods ranging from EEG (electroencephalography), through voltage sensitive dye imaging, down to recordings from single neurons. Ongoing cortical activity has been shown to play a critical role in development, and must also be essential for processing sensory perception, because it modulates stimulus-evoked activity, and is correlated with behaviour. Yet its role in the processing of external information and its relationship to internal representations of sensory attributes remains unknown. Using voltage sensitive dye imaging, we previously established a close link between ongoing activity in the visual cortex of anaesthetized cats and the spontaneous firing of a single neuron. Here we report that such activity encompasses a set of dynamically switching cortical states, many of which correspond closely to orientation maps. When such an orientation state emerged spontaneously, it spanned several hypercolumns and was often followed by a state corresponding to a proximal orientation. We suggest that dynamically switching cortical states could represent the brain's internal context, and therefore reflect or influence memory, perception and behaviour.

  12. Forest Fire Occurrence in Southern Counties, 1966-1975

    Science.gov (United States)

    M.L. Doolittle

    1977-01-01

    Forest fire occurrence data for individual protection units generally are unavailable outside particular state organization. Number of fires, area protected and fire occurrence rate (fires per 1,000,000 acres) from 1966 to 1975, are presented in tables for the 993 counties under protection in 13 southern states. These data are compared with data for the preceeding...

  13. Aids to determining fuel models for estimating fire behavior

    Science.gov (United States)

    Hal E. Anderson

    1982-01-01

    Presents photographs of wildland vegetation appropriate for the 13 fuel models used in mathematical models of fire behavior. Fuel model descriptions include fire behavior associated with each fuel and its physical characteristics. A similarity chart cross-references the 13 fire behavior fuel models to the 20 fuel models used in the National Fire Danger Rating System....

  14. Active Fire Mapping Program

    Science.gov (United States)

    Active Fire Mapping Program Current Large Incidents (Home) New Large Incidents Fire Detection Maps MODIS Satellite Imagery VIIRS Satellite Imagery Fire Detection GIS Data Fire Data in Google Earth ...

  15. Fire Safety (For Parents)

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español Fire Safety KidsHealth / For Parents / Fire Safety What's in ... event of a fire emergency in your home. Fire Prevention Of course, the best way to practice ...

  16. Fire Research Enclosure

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Simulates submarine fires, enclosed aircraft fires, and fires in enclosures at shore facilities .DESCRIPTION: FIRE I is a pressurizable, 324 cu m(11,400 cu...

  17. Fire characteristics associated with firefighter injury on large federal wildland fires.

    Science.gov (United States)

    Britton, Carla; Lynch, Charles F; Torner, James; Peek-Asa, Corinne

    2013-02-01

    Wildland fires present many injury hazards to firefighters. We estimate injury rates and identify fire-related factors associated with injury. Data from the National Interagency Fire Center from 2003 to 2007 provided the number of injuries in which the firefighter could not return to his or her job assignment, person-days worked, and fire characteristics (year, region, season, cause, fuel type, resistance to control, and structures destroyed). We assessed fire-level risk factors of having at least one reported injury using logistic regression. Negative binomial regression was used to examine incidence rate ratios associated with fire-level risk factors. Of 867 fires, 9.5% required the most complex management and 24.7% required the next-highest level of management. Fires most often occurred in the western United States (82.8%), during the summer (69.6%), caused by lightening (54.9%). Timber was the most frequent fuel source (40.2%). Peak incident management level, person-days of exposure, and the fire's resistance to control were significantly related to the odds of a fire having at least one reported injury. However, the most complex fires had a lower injury incidence rate than less complex fires. Although fire complexity and the number of firefighters were associated with the risk for at least one reported injury, the more experienced and specialized firefighting teams had lower injury incidence. Copyright © 2013 Elsevier Inc. All rights reserved.

  18. Fire analyses in central and disposal tunnels by APROS

    International Nuclear Information System (INIS)

    Peltokorpi, L.; Kukkola, T.; Nieminen, J.

    2012-12-01

    The central tunnels and the disposal tunnels on the north-east disposal area are the target areas of the fire studies. Target is to maintain under pressure in the fire zone in case of a fire. In the central tunnels a fire of a drilling jumbo with moderate fire propagation is used as heat release rate. In the disposal tunnel the heat release rate of a canister transfer and installation vehicle fire received as a result of the pyrolysis analyze as well as an average heat release rate of a van fire are used. Inlet air is to be conducted to the back end of the fire zone and the exhaust is to be lead out from the beginning of the fire zone. The worst location of the fire is in the beginning of the fire zone just below of the exhaust air clap valve. The size of the fire zone does not have big impact on pressure. In all analyzed cases the fire zone remains too long time over pressurized. Inlet air flow of a 30 m 3 /s is too much. The rotation controlled booster blowers will solve the pressure problems of the fire zone in fire cases. The rotation is controlled by the fire zone pressure. The fire of the canister transfer and installation vehicle in the central tunnel will not cause problems. The disposal tunnel fire door should be kept open, if the canister transfer and installation vehicle or the bentonite blocks transfer and installation vehicle is driven into the disposal tunnel. If a fire is caught in the disposal tunnel then the fire zone in the central tunnel is to be closed and the pressure is controlled by the rotation controlled booster blowers. If a personnel car or a van is driven into the disposal tunnel, then fire door of the disposal is to be kept closed against fires in the central tunnel. (orig.)

  19. Synthesis of knowledge of extreme fire behavior: volume I for fire managers

    Science.gov (United States)

    Paul A. Werth; Brian E. Potter; Craig B. Clements; Mark A. Finney; Scott L. Goodrick; Martin E. Alexander; Miguel G. Cruz; Jason A. Forthofer; Sara S. McAllister

    2011-01-01

    The National Wildfire Coordinating Group definition of extreme fire behavior (EFB) indicates a level of fire behavior characteristics that ordinarily precludes methods of direct control action. One or more of the following is usually involved: high rate of spread, prolific crowning/spotting, presence of fire whirls, and strong convection column. Predictability is...

  20. Econometric analysis of fire suppression production functions for large wildland fires

    Science.gov (United States)

    Thomas P. Holmes; David E. Calkin

    2013-01-01

    In this paper, we use operational data collected for large wildland fires to estimate the parameters of economic production functions that relate the rate of fireline construction with the level of fire suppression inputs (handcrews, dozers, engines and helicopters). These parameter estimates are then used to evaluate whether the productivity of fire suppression inputs...

  1. Synthesis of knowledge of extreme fire behavior: volume 2 for fire behavior specialists, researchers, and meteorologists

    Science.gov (United States)

    Paul A. Werth; Brian E. Potter; Martin E. Alexander; Craig B. Clements; Miguel G. Cruz; Mark A. Finney; Jason M. Forthofer; Scott L. Goodrick; Chad Hoffman; W. Matt Jolly; Sara S. McAllister; Roger D. Ottmar; Russell A. Parsons

    2016-01-01

    The National Wildfire Coordinating Group’s definition of extreme fire behavior indicates a level of fire behavior characteristics that ordinarily precludes methods of direct control action. One or more of the following is usually involved: high rate of spread, prolific crowning/ spotting, presence of fire whirls, and strong convection column. Predictability is...

  2. Fire behavior, weather, and burn severity of the 2007 Anaktuvuk River tundra fire, North Slope, Alaska

    Science.gov (United States)

    Benjamin M. Jones; Crystal A. Kolden; Randi Jandt; John T. Abatzoglu; Frank Urban; Christopher D. Arp

    2009-01-01

    In 2007, the Anaktuvuk River Fire (ARF) became the largest recorded tundra fire on the North Slope of Alaska. The ARF burned for nearly three months, consuming more than 100,000 ha. At its peak in early September, the ARF burned at a rate of 7000 ha d-1. The conditions potentially responsible for this large tundra fire include modeled record high...

  3. Remote sensing fire and fuels in southern California

    Science.gov (United States)

    Philip Riggan; Lynn Wolden; Bob Tissell; David Weise; J. Coen

    2011-01-01

    Airborne remote sensing at infrared wavelengths has the potential to quantify large-fire properties related to energy release or intensity, residence time, fuel-consumption rate, rate of spread, and soil heating. Remote sensing at a high temporal rate can track fire-line outbreaks and acceleration and spotting ahead of a fire front. Yet infrared imagers and imaging...

  4. Fire resistance of wood members with directly applied protection

    Science.gov (United States)

    Robert H. White

    2009-01-01

    Fire-resistive wood construction is achieved either by having the structural elements be part of fire-rated assemblies or by using elements of sufficient size that the elements themselves have the required fire-resistance ratings. For exposed structural wood elements, the ratings in the United States are calculated using either the T.T. Lie method or the National...

  5. Recurrent spontaneous intracerebral hemorrhage associated with ...

    African Journals Online (AJOL)

    Spontaneous intracerebral hemorrhage (ICH) accounts for 15% of stroke cases in the US and Europe and up to 30% in Asian populations. Intracerebral hemorrhage is a relatively uncommon form of stroke-it causes only 10 to 15 percent of all strokes. It is more disabling and has a higher mortality rate than ischemic stroke, ...

  6. Spontaneous emission control in a tunable hybrid photonic system

    NARCIS (Netherlands)

    Frimmer, M.; Koenderink, A.F.

    2013-01-01

    We experimentally demonstrate control of the rate of spontaneous emission in a tunable hybrid photonic system that consists of two canonical building blocks for spontaneous emission control, an optical antenna and a mirror, each providing a modification of the local density of optical states (LDOS).

  7. Modelling of Fire in an Open Car Park

    DEFF Research Database (Denmark)

    Marton, Timea; Dederichs, Anne Simone; Giuliani, Luisa

    2015-01-01

    Steel car parks exhibit high vulnerability to fire, as a consequence of the degradation of the steel mechanical properties at high temperatures and of the combustible type and amount. Real fire accidents in open car parks demonstrated a much faster and extended fire spread than predictions......, assuming that a fire spread rate of 12 min and consider at most 3-4 vehicles on fire at the same time. Fire Dynamic Simulator (FDS) is applied in this current paper to study fire spread between cars. The outcomes of the investigations show that the fire spread is strongly influenced by the geometrical...... layout and that the distance between cars plays a determinant role on the fire spread rate and ignition of adjacent cars. In particular it was found that the fire spread can be faster than 12 minutes in the case of the cars parked 40 and 60 cm from each other....

  8. Spontaneous tension haemopneumothorax

    OpenAIRE

    Patterson, Benjamin Oliver; Itam, Sarah; Probst, Fey

    2008-01-01

    Abstract We present a patient with sudden onset progressive shortness of breath and no history of trauma, who rapidly became haemodynamically compromised with a pneumothorax and pleural effusion seen on chest radiograph. He was treated for spontaneous tension pneumothorax but this was soon revealed to be a tension haemopneumothorax. He underwent urgent thoracotomy after persistent bleeding to explore an apical vascular abnormality seen on CT scanning. To our knowledge this is the first such c...

  9. Spontaneous spinal epidural abscess.

    LENUS (Irish Health Repository)

    Ellanti, P

    2011-10-01

    Spinal epidural abscess is an uncommon entity, the frequency of which is increasing. They occur spontaneously or as a complication of intervention. The classical triad of fever, back pain and neurological symptoms are not always present. High index of suspicion is key to diagnosis. Any delay in diagnosis and treatment can have significant neurological consequences. We present the case of a previously well man with a one month history of back pain resulting from an epidural abscess.

  10. Spontaneous polyploidization in cucumber.

    Science.gov (United States)

    Ramírez-Madera, Axel O; Miller, Nathan D; Spalding, Edgar P; Weng, Yiqun; Havey, Michael J

    2017-07-01

    This is the first quantitative estimation of spontaneous polyploidy in cucumber and we detected 2.2% polyploids in a greenhouse study. We provide evidence that polyploidization is consistent with endoreduplication and is an on-going process during plant growth. Cucumber occasionally produces polyploid plants, which are problematic for growers because these plants produce misshaped fruits with non-viable seeds. In this study, we undertook the first quantitative study to estimate the relative frequency of spontaneous polyploids in cucumber. Seeds of recombinant inbred lines were produced in different environments, plants were grown in the field and greenhouse, and flow cytometry was used to establish ploidies. From 1422 greenhouse-grown plants, the overall relative frequency of spontaneous polyploidy was 2.2%. Plants possessed nuclei of different ploidies in the same leaves (mosaic) and on different parts of the same plant (chimeric). Our results provide evidence of endoreduplication and polysomaty in cucumber, and that it is an on-going and dynamic process. There was a significant effect (p = 0.018) of seed production environment on the occurrence of polyploid plants. Seed and seedling traits were not accurate predictors of eventual polyploids, and we recommend that cucumber producers rogue plants based on stature and leaf serration to remove potential polyploids.

  11. Spontaneous, local diastolic subsarcolemmal calcium releases in single, isolated guinea-pig sinoatrial nodal cells.

    Science.gov (United States)

    Sirenko, Syevda G; Yang, Dongmei; Maltseva, Larissa A; Kim, Mary S; Lakatta, Edward G; Maltsev, Victor A

    2017-01-01

    Uptake and release calcium from the sarcoplasmic reticulum (SR) (dubbed "calcium clock"), in the form of spontaneous, rhythmic, local diastolic calcium releases (LCRs), together with voltage-sensitive ion channels (membrane clock) form a coupled system that regulates the action potential (AP) firing rate. LCRs activate Sodium/Calcium exchanger (NCX) that accelerates diastolic depolarization and thus participating in regulation of the time at which the next AP will occur. Previous studies in rabbit SA node cells (SANC) demonstrated that the basal AP cycle length (APCL) is tightly coupled to the basal LCR period (time from the prior AP-induced Ca2+ transient to the diastolic LCR occurrence), and that this coupling is further modulated by autonomic receptor stimulation. Although spontaneous LCRs during diastolic depolarization have been reported in SANC of various species (rabbit, cat, mouse, toad), prior studies have failed to detect LCRs in spontaneously beating SANC of guinea-pig, a species that has been traditionally used in studies of cardiac pacemaker cell function. We performed a detailed investigation of whether guinea-pig SANC generate LCRs and whether they play a similar key role in regulation of the AP firing rate. We used two different approaches, 2D high-speed camera and classical line-scan confocal imaging. Positioning the scan-line beneath sarcolemma, parallel to the long axis of the cell, we found that rhythmically beating guinea-pig SANC do, indeed, generate spontaneous, diastolic LCRs beneath the surface membrane. The average key LCR characteristics measured in confocal images in guinea-pig SANC were comparable to rabbit SANC, both in the basal state and in the presence of β-adrenergic receptor stimulation. Moreover, the relationship between the LCR period and APCL was subtended by the same linear function. Thus, LCRs in guinea-pig SANC contribute to the diastolic depolarization and APCL regulation. Our findings indicate that coupled-clock system

  12. Video-assisted thoracoscopy treatment of spontaneous pneumothorax

    International Nuclear Information System (INIS)

    Chen Haitao; Ren Jian; Che Jiaming; Hang Junbiao; Qiu Weicheng; Chen Zhongyuan

    2002-01-01

    Objective: To propose a treatment protocol by video thoracoscopy in spontaneous pneumothorax. Methods: One hundred and three patients underwent Video-assisted thoracoscopy (VATS) treatment of spontaneous pneumothorax and hemothorax. Indications included recurrent pneumothorax, persistent air leakage following conservative therapy, complicated hemothorax and CT scan identified bullae formation. Results: No operative deaths occurred, conversion rate was 2.91%, recurrence rate was 0.97%, complication rate was 3.81% and mean postoperative hospital stay was 5.6 days. Conclusions: VATS treatment of spontaneous pneumothorax is better than open chest surgery and also superior than conservative therapy

  13. Fire Behavior (FB)

    Science.gov (United States)

    Robert E. Keane

    2006-01-01

    The Fire Behavior (FB) method is used to describe the behavior of the fire and the ambient weather and fuel conditions that influence the fire behavior. Fire behavior methods are not plot based and are collected by fire event and time-date. In general, the fire behavior data are used to interpret the fire effects documented in the plot-level sampling. Unlike the other...

  14. Prove of structural fire design in nuclear power plants

    International Nuclear Information System (INIS)

    Schneider, U.; Hosser, D.; Max, U.

    1986-01-01

    Based on the application of comprehensive heat balance calculations the whole parameters like geometry, fire load, ventilation conditions etc. of a German PWR were covered. A practical design procedure based on diagrams was developed whereby separate diagrams for oil and cable fires were presented. A probabilistic safety concept was employed as to account for the specific variations of fire parameters as fire load and area, ventilation condition, rate of burning. With respect to the frequency of fire occurrences and the impact of fire fighting measures on the spread of fires latest statistical data of a special BMI investigation were used. (orig./HP) [de

  15. Detection and delineation of coal mine fire in Jharia coal field (JCF ...

    Indian Academy of Sciences (India)

    71

    Africa, Indonesia, Poland (Zhang et al. 2005; Kuenzer et al. .... is about 8 Km in west direction from Dhanbad Rrailway station. The location of the ...... International conference on Spontaneous coal seam fires: Mitigating a global. 543 disaster at ...

  16. Fire Symfonier

    DEFF Research Database (Denmark)

    Nielsen, Svend Hvidtfelt

    2009-01-01

    sidste fire symfonier. Den er måske snarere at opfatte som et præludium til disse. At påstå, at symfonierne fra Holmboes side er planlagt til at være beslægtede, ville være at gå for vidt. Alene de 26 år, der skiller den 10. fra den 13., gør påstanden - i bedste fald - dubiøs. Når deres udformning...... udkrystallisering som i de sidste små 30 år af hans virke har afkastet disse fire variationer over en grundlæggende central holmboesk fornemmelse for form, melodi, klang og rytme. Denne oplevelse har fået mig til at udforske symfonierne, for at finde til bunds i dette holmboeske fællestræk, som jeg mener her står...

  17. Cytosolic calcium ions exert a major influence on the firing rate and maintenance of pacemaker activity in guinea-pig sinus node.

    Directory of Open Access Journals (Sweden)

    Rebecca Anne Capel

    2015-02-01

    Full Text Available The sino-atrial node (SAN provides the electrical stimulus to initiate every heart beat. Cellular processes underlying this activity have been debated extensively, especially with regards to the role of intracellular calcium. We have used whole-cell application of 1,2-bis(o-aminophenoxyethane-N,N,N',N'-tetraacetic acid (BAPTA, a rapid calcium chelator, to guinea pig isolated SAN myocytes to assess the effect of rapid reduction of intracellular calcium on SAN cell electrical activity. High-dose (10 mM BAPTA induced rapid and complete cessation of rhythmic action potential (AP firing (time to cessation 5.5±1.7 s. Over a range of concentrations, BAPTA induced slowing of action potential firing and disruption of rhythmic activity, which was dose-dependent in its time of onset. Exposure to BAPTA was associated with stereotyped action potential changes similar to those previously reported in the presence of ryanodine, namely depolarisation of the most negative diastolic potential, prolongation of action potentials and a reduction in action potential amplitude. These experiments are consistent with the view that cytosolic calcium is essential to the maintenance of rhythmic pacemaker activity.

  18. Electrophysiological study in the infraorbital nerve of the rat: Spontaneous and evoked activity

    Energy Technology Data Exchange (ETDEWEB)

    AlbarracIn, A L [Catedra de Neurociencias, Facultad de Medicina, Universidad Nacional de Tucuman, Av. Roca 2200, PC 4000 (Argentina); Farfan, F D [Departamento de BioingenierIa, FACET, Universidad Nacional de Tucuman, INSIBIO - CONICET, CC 327, PC 4000 (Argentina); Felice, C J [Departamento de BioingenierIa, FACET, Universidad Nacional de Tucuman, INSIBIO - CONICET, CC 327, PC 4000 (Argentina)

    2007-11-15

    In this work we present some studies in the afferent nerve of the rat vibrissae. Studies on spontaneous activity (SA) in this sensorial system are of long data. Nevertheless, SA recordings in the nerve of a single vibrissa have not been made until present. In this work, we use an algorithm based on signal decomposition with Continuous Wavelet Transform (CWT) to analyse the discharges of two nerves. The action potentials of both nerves were detected and the firing rates were calculated. These results suggest that the firing rate of one vibrissa innervation is low considering that this nerve contains hundred of fibers. In addition, we present preliminary studies suggesting important effects of the hair shaft length in the afferent discharge during the vibrissae movements. The experiments consisted in recording the nerve activity after the vibrissae were sectioned at two different levels. The results showed important differences in the signal energy contents. It suggests that the hair shaft length would produce a differential activation of the mechanoreceptors located in the vibrissae follicle.

  19. Electrophysiological study in the infraorbital nerve of the rat: Spontaneous and evoked activity

    International Nuclear Information System (INIS)

    AlbarracIn, A L; Farfan, F D; Felice, C J

    2007-01-01

    In this work we present some studies in the afferent nerve of the rat vibrissae. Studies on spontaneous activity (SA) in this sensorial system are of long data. Nevertheless, SA recordings in the nerve of a single vibrissa have not been made until present. In this work, we use an algorithm based on signal decomposition with Continuous Wavelet Transform (CWT) to analyse the discharges of two nerves. The action potentials of both nerves were detected and the firing rates were calculated. These results suggest that the firing rate of one vibrissa innervation is low considering that this nerve contains hundred of fibers. In addition, we present preliminary studies suggesting important effects of the hair shaft length in the afferent discharge during the vibrissae movements. The experiments consisted in recording the nerve activity after the vibrissae were sectioned at two different levels. The results showed important differences in the signal energy contents. It suggests that the hair shaft length would produce a differential activation of the mechanoreceptors located in the vibrissae follicle

  20. Burns resulting from spontaneous combustion of electronic cigarettes: a case series

    OpenAIRE

    Sheckter, Clifford; Chattopadhyay, Arhana; Paro, John; Karanas, Yvonne

    2016-01-01

    Background Electronic cigarette (e-cigarette) sales have grown rapidly in recent years, coinciding with a public perception that they are a safer alternative to traditional cigarettes. However, there have been numerous media reports of fires associated with e-cigarette spontaneous combustion. Case Presentation Three severe burns caused by spontaneous combustion of e-cigarettes within a 6-month period were treated at the Santa Clara Valley Medical Center Burn Unit. Patients sustained partial a...

  1. Delay-induced diversity of firing behavior and ordered chaotic firing in adaptive neuronal networks

    International Nuclear Information System (INIS)

    Gong Yubing; Wang Li; Xu Bo

    2012-01-01

    In this paper, we study the effect of time delay on the firing behavior and temporal coherence and synchronization in Newman–Watts thermosensitive neuron networks with adaptive coupling. At beginning, the firing exhibit disordered spiking in absence of time delay. As time delay is increased, the neurons exhibit diversity of firing behaviors including bursting with multiple spikes in a burst, spiking, bursting with four, three and two spikes, firing death, and bursting with increasing amplitude. The spiking is the most ordered, exhibiting coherence resonance (CR)-like behavior, and the firing synchronization becomes enhanced with the increase of time delay. As growth rate of coupling strength or network randomness increases, CR-like behavior shifts to smaller time delay and the synchronization of firing increases. These results show that time delay can induce diversity of firing behaviors in adaptive neuronal networks, and can order the chaotic firing by enhancing and optimizing the temporal coherence and enhancing the synchronization of firing. However, the phenomenon of firing death shows that time delay may inhibit the firing of adaptive neuronal networks. These findings provide new insight into the role of time delay in the firing activity of adaptive neuronal networks, and can help to better understand the complex firing phenomena in neural networks.

  2. Spontaneously broken mass

    International Nuclear Information System (INIS)

    Endlich, Solomon; Nicolis, Alberto; Penco, Riccardo

    2015-01-01

    The Galilei group involves mass as a central charge. We show that the associated superselection rule is incompatible with the observed phenomenology of superfluid helium 4: this is recovered only under the assumption that mass is spontaneously broken. This remark is somewhat immaterial for the real world, where the correct space-time symmetries are encoded by the Poincaré group, which has no central charge. Yet it provides an explicit example of how superselection rules can be experimentally tested. We elaborate on what conditions must be met for our ideas to be generalizable to the relativistic case of the integer/half-integer angular momentum superselection rule.

  3. Reactivation of Rate Remapping in CA3.

    Science.gov (United States)

    Schwindel, C Daniela; Navratilova, Zaneta; Ali, Karim; Tatsuno, Masami; McNaughton, Bruce L

    2016-09-07

    The hippocampus is thought to contribute to episodic memory by creating, storing, and reactivating patterns that are unique to each experience, including different experiences that happen at the same location. Hippocampus can combine spatial and contextual/episodic information using a dual coding scheme known as "global" and "rate" remapping. Global remapping selects which set of neurons can activate at a given location. Rate remapping readjusts the firing rates of this set depending on current experience, thus expressing experience-unique patterns at each location. But can the experience-unique component be retrieved spontaneously? Whereas reactivation of recent, spatially selective patterns in hippocampus is well established, it is never perfect, raising the issue of whether the experiential component might be absent. This question is key to the hypothesis that hippocampus can assist memory consolidation by reactivating and broadcasting experience-specific "index codes" to neocortex. In CA3, global remapping exhibits attractor-like dynamics, whereas rate remapping apparently does not, leading to the hypothesis that only the former can be retrieved associatively and casting doubt on the general consolidation hypothesis. Therefore, we studied whether the rate component is reactivated spontaneously during sleep. We conducted neural ensemble recordings from CA3 while rats ran on a circular track in different directions (in different sessions) and while they slept. It was shown previously that the two directions of running result in strong rate remapping. During sleep, the most recent rate distribution was reactivated preferentially. Therefore, CA3 can retrieve patterns spontaneously that are unique to both the location and the content of recent experience. The hippocampus is required for memory of events and their spatial contexts. The primary correlate of hippocampal activity is location in space, but multiple memories can occur in the same location. To be useful

  4. Browns Ferry fire

    International Nuclear Information System (INIS)

    Harkleroad, J.R.

    1983-01-01

    A synopsis of the March 22, 1975 fire at Browns Ferry Nuclear Plant is discussed. Emphasis is placed on events prior to and during the fire. How the fire started, fire fighting activities, fire and smoke development, and restoration activities are discussed

  5. Spread and burning behavior of continuous spill fires

    DEFF Research Database (Denmark)

    Zhao, Jinlong; Huang, Hong; Jomaas, Grunde

    2017-01-01

    Spill fire experiments with continuous discharge on a fireproof glass sheet were conducted to improve the understanding of spill fire spread and burning. Ethanol was used as the fuel and the discharge rate was varied from 2.8. mL/s to 7.6. mL/s. Three ignition conditions were used...... in the experiments; no ignition, instantaneous ignition and delayed ignition. The spread rate, regression rate, penetrated thermal radiation and the temperature of the bottom glass were analyzed. The experiments clearly show the entire spread process for spill fires. Further, the regression rate of spill fires...... at the quasi-steady burning was lower than that of pool fires and the ratio of the spill fires' regression rate to the pool fires' regression rate was found to be approximately 0.89. With respect to the radiative penetration and the heat conduction between the fuel layer and the glass, a regression rate...

  6. The Impact of Stimulation Induced Short Term Synaptic Plasticity on Firing Patterns in the Globus Pallidus of the Rat

    Directory of Open Access Journals (Sweden)

    Jenia eBugaysen

    2011-03-01

    Full Text Available Electrical stimulation in the globus pallidus (GP leads to complex modulations of neuronal activity in the stimulated nucleus. Multiple in-vivo studies have demonstrated the modulation of both firing rates and patterns during and immediately following the GP stimulation. Previous in-vitro studies, together with computational studies, have suggested the involvement of short-term synaptic plasticity (STP during the stimulation. The aim of the current study was to explore in-vitro the effects of STP on neuronal activity of GP neurons during local repetitive stimulation. We recorded synaptic potentials and assessed the modulations of spontaneous firing in a postsynaptic neuron in acute brain slices via a whole-cell pipette. Low-frequency repetitive stimulation locked the firing of the neuron to the stimulus. However, high-frequency repetitive stimulation in the GP generated a biphasic modulation of the firing frequency consisting of inhibitory and excitatory phases. Using blockers of synaptic transmission, we show that GABAergic synapses mediated the inhibitory and glutamatergic synapses the excitatory part of the response. Furthermore, we report that at high stimulation frequencies both types of synapses undergo short-term depression leading to a time dependent modulation of the neuronal firing. These findings indicate that STP modulates the dynamic responses of pallidal activity during electrical stimulation, and may contribute to a better understanding of the mechanism underlying deep brain stimulation (DBS like protocols.

  7. Atypical dopamine transporter inhibitors R-modafinil and JHW 007 differentially affect D2 autoreceptor neurotransmission and the firing rate of midbrain dopamine neurons.

    Science.gov (United States)

    Avelar, Alicia J; Cao, Jianjing; Newman, Amy Hauck; Beckstead, Michael J

    2017-09-01

    Abuse of psychostimulants like cocaine that inhibit dopamine (DA) reuptake through the dopamine transporter (DAT) represents a major public health issue, however FDA-approved pharmacotherapies have yet to be developed. Recently a class of ligands termed "atypical DAT inhibitors" has gained attention due to their range of effectiveness in increasing extracellular DA levels without demonstrating significant abuse liability. These compounds not only hold promise as therapeutic agents to treat stimulant use disorders but also as experimental tools to improve our understanding of DAT function. Here we used patch clamp electrophysiology in mouse brain slices to explore the effects of two atypical DAT inhibitors (R-modafinil and JHW 007) on the physiology of single DA neurons in the substantia nigra and ventral tegmental area. Despite their commonalities of being DAT inhibitors that lack cocaine-like behavioral profiles, these compounds exhibited surprisingly divergent cellular effects. Similar to cocaine, R-modafinil slowed DA neuron firing in a D2 receptor-dependent manner and rapidly enhanced the amplitude and duration of D2 receptor-mediated currents in the midbrain. In contrast, JHW 007 exhibited little effect on firing, slow DAT blockade, and an unexpected inhibition of D2 receptor-mediated currents that may be due to direct D2 receptor antagonism. Furthermore, pretreatment with JHW 007 blunted the cellular effects of cocaine, suggesting that it may be valuable to investigate similar DAT inhibitors as potential therapeutic agents. Further exploration of these and other atypical DAT inhibitors may reveal important cellular effects of compounds that will have potential as pharmacotherapies for treating cocaine use disorders. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Spontaneous Tumor Lysis Syndrome

    Directory of Open Access Journals (Sweden)

    Alicia C. Weeks MD

    2015-08-01

    Full Text Available Tumor lysis syndrome (TLS is a known complication of malignancy and its treatment. The incidence varies on malignancy type, but is most common with hematologic neoplasms during cytotoxic treatment. Spontaneous TLS is thought to be rare. This case study is of a 62-year-old female admitted with multisystem organ failure, with subsequent diagnosis of aggressive B cell lymphoma. On admission, laboratory abnormalities included renal failure, elevated uric acid (20.7 mg/dL, and 3+ amorphous urates on urinalysis. Oliguric renal failure persisted despite aggressive hydration and diuretic use, requiring initiation of hemodialysis prior to chemotherapy. Antihyperuricemic therapy and hemodialysis were used to resolve hyperuricemia. However, due to multisystem organ dysfunction syndrome with extremely poor prognosis, the patient ultimately expired in the setting of a terminal ventilator wean. Although our patient did not meet current TLS criteria, she required hemodialysis due to uric acid nephropathy, a complication of TLS. This poses the clinical question of whether adequate diagnostic criteria exist for spontaneous TLS and if the lack of currently accepted guidelines has resulted in the underestimation of its incidence. Allopurinol and rasburicase are commonly used for prevention and treatment of TLS. Although both drugs decrease uric acid levels, allopurinol mechanistically prevents formation of the substrate rasburicase acts to solubilize. These drugs were administered together in our patient, although no established guidelines recommend combined use. This raises the clinical question of whether combined therapy is truly beneficial or, conversely, detrimental to patient outcomes.

  9. Spontaneous intracranial hypotension

    International Nuclear Information System (INIS)

    Cardwell, C.; Cox, I.; Baldey, A.

    2002-01-01

    Full text: A 49-year old female presented with severe postural headache with no history of trauma. A Computed Tomography (CT) study of the brain demonstrated abnormal meningeal enhancement raising the possibility of leptomeningeal metastases. The patient was then referred to Magnetic Resonance Imaging (MRI) which demonstrated diffuse smooth dural enhancement with ancillary findings characteristic of spontaneous intracranial hypotension. The patient was then referred to Nuclear Medicine to confirm the diagnosis and localise the presumed leak 400MBq of 99mTc DTPA was injected via lumbar puncture into the L3-L4 subarachnoid space Posterior images of the spine were taken with a GE XRT single head gamma camera at 1 and 4 hours post administration of radionuclide. Images demonstrated abnormal early arrival of radionuclide in the kidneys and bladder at 1 hour and abnormal leak of tracer was demonstrate at the level of the first thoracic vertebra on the right side at 4 hours. This confirmed CSF leak at this level. Consequently the patient underwent a blood patch and her symptoms resolved. Spontaneous Intracranial Hypotension is a syndrome often unrecognised presenting with symptoms including severe postural headache neck stiffness nausea vomiting tinnitus and vertigo. The diagnosis is frequently suspected from findings on MRI, but Nuclear Medicine CSF imaging provides a readily available and cost effective method for confirming the diagnosis, and for making the diagnosis in patients who are unsuitable for or do not have access to MRI. Copyright (2002) The Australian and New Zealand Society of Nuclear Medicine Inc

  10. Spontaneous intracranial hypotension

    Energy Technology Data Exchange (ETDEWEB)

    Cardwell, C; Cox, I; Baldey, A [St. F.X. Cabrini Hospital, VIC (Australia). Departments of Nuclear Medicine and Magnetic Resonance Imaging

    2002-07-01

    Full text: A 49-year old female presented with severe postural headache with no history of trauma. A Computed Tomography (CT) study of the brain demonstrated abnormal meningeal enhancement raising the possibility of leptomeningeal metastases. The patient was then referred to Magnetic Resonance Imaging (MRI) which demonstrated diffuse smooth dural enhancement with ancillary findings characteristic of spontaneous intracranial hypotension. The patient was then referred to Nuclear Medicine to confirm the diagnosis and localise the presumed leak 400MBq of 99mTc DTPA was injected via lumbar puncture into the L3-L4 subarachnoid space Posterior images of the spine were taken with a GE XRT single head gamma camera at 1 and 4 hours post administration of radionuclide. Images demonstrated abnormal early arrival of radionuclide in the kidneys and bladder at 1 hour and abnormal leak of tracer was demonstrate at the level of the first thoracic vertebra on the right side at 4 hours. This confirmed CSF leak at this level. Consequently the patient underwent a blood patch and her symptoms resolved. Spontaneous Intracranial Hypotension is a syndrome often unrecognised presenting with symptoms including severe postural headache neck stiffness nausea vomiting tinnitus and vertigo. The diagnosis is frequently suspected from findings on MRI, but Nuclear Medicine CSF imaging provides a readily available and cost effective method for confirming the diagnosis, and for making the diagnosis in patients who are unsuitable for or do not have access to MRI. Copyright (2002) The Australian and New Zealand Society of Nuclear Medicine Inc.

  11. Analysis of large urban fires

    International Nuclear Information System (INIS)

    Kang, S.W.; Reitter, T.A.; Takata, A.N.

    1984-11-01

    Fires in urban areas caused by a nuclear burst are analyzed as a first step towards determining their smoke-generation chacteristics, which may have grave implications for global-scale climatic consequences. A chain of events and their component processes which would follow a nuclear attack are described. A numerical code is currently being developed to calculate ultimately the smoke production rate for a given attack scenario. Available models for most of the processes are incorporated into the code. Sample calculations of urban fire-development history performed in the code for an idealized uniform city are presented. Preliminary results indicate the importance of the wind, thermal radiation transmission, fuel distributions, and ignition thresholds on the urban fire spread characteristics. Future plans are to improve the existing models and develop new ones to characterize smoke production from large urban fires. 21 references, 18 figures

  12. WASTE HANDLING BUILDING FIRE PROTECTION SYSTEM DESCRIPTION DOCUMENT

    Energy Technology Data Exchange (ETDEWEB)

    J. D. Bigbee

    2000-06-21

    The Waste Handling Building Fire Protection System provides the capability to detect, control, and extinguish fires and/or mitigate explosions throughout the Waste Handling Building (WHB). Fire protection includes appropriate water-based and non-water-based suppression, as appropriate, and includes the distribution and delivery systems for the fire suppression agents. The Waste Handling Building Fire Protection System includes fire or explosion detection panel(s) controlling various detectors, system actuation, annunciators, equipment controls, and signal outputs. The system interfaces with the Waste Handling Building System for mounting of fire protection equipment and components, location of fire suppression equipment, suppression agent runoff, and locating fire rated barriers. The system interfaces with the Waste Handling Building System for adequate drainage and removal capabilities of liquid runoff resulting from fire protection discharges. The system interfaces with the Waste Handling Building Electrical Distribution System for power to operate, and with the Site Fire Protection System for fire protection water supply to automatic sprinklers, standpipes, and hose stations. The system interfaces with the Site Fire Protection System for fire signal transmission outside the WHB as needed to respond to a fire emergency, and with the Waste Handling Building Ventilation System to detect smoke and fire in specific areas, to protect building high-efficiency particulate air (HEPA) filters, and to control portions of the Waste Handling Building Ventilation System for smoke management and manual override capability. The system interfaces with the Monitored Geologic Repository (MGR) Operations Monitoring and Control System for annunciation, and condition status.

  13. WASTE HANDLING BUILDING FIRE PROTECTION SYSTEM DESCRIPTION DOCUMENT

    International Nuclear Information System (INIS)

    J. D. Bigbee

    2000-01-01

    The Waste Handling Building Fire Protection System provides the capability to detect, control, and extinguish fires and/or mitigate explosions throughout the Waste Handling Building (WHB). Fire protection includes appropriate water-based and non-water-based suppression, as appropriate, and includes the distribution and delivery systems for the fire suppression agents. The Waste Handling Building Fire Protection System includes fire or explosion detection panel(s) controlling various detectors, system actuation, annunciators, equipment controls, and signal outputs. The system interfaces with the Waste Handling Building System for mounting of fire protection equipment and components, location of fire suppression equipment, suppression agent runoff, and locating fire rated barriers. The system interfaces with the Waste Handling Building System for adequate drainage and removal capabilities of liquid runoff resulting from fire protection discharges. The system interfaces with the Waste Handling Building Electrical Distribution System for power to operate, and with the Site Fire Protection System for fire protection water supply to automatic sprinklers, standpipes, and hose stations. The system interfaces with the Site Fire Protection System for fire signal transmission outside the WHB as needed to respond to a fire emergency, and with the Waste Handling Building Ventilation System to detect smoke and fire in specific areas, to protect building high-efficiency particulate air (HEPA) filters, and to control portions of the Waste Handling Building Ventilation System for smoke management and manual override capability. The system interfaces with the Monitored Geologic Repository (MGR) Operations Monitoring and Control System for annunciation, and condition status

  14. The ducky2J mutation in Cacna2d2 results in reduced spontaneous Purkinje cell activity and altered gene expression

    Science.gov (United States)

    Donato, Roberta; Page, Karen M.; Koch, Dietlind; Nieto-Rostro, Manuela; Foucault, Isabelle; Davies, Anthony; Wilkinson, Tonia; Rees, Michele; Edwards, Frances A.; Dolphin, Annette C.

    2006-01-01

    The mouse mutant ducky and its allele ducky2J represent a model for absence epilepsy characterized by spike-wave seizures, and cerebellar ataxia. These mice have mutations in Cacna2d2, which encodes the α2δ-2 calcium channel subunit. Of relevance to the ataxic phenotype, α2δ-2 mRNA is strongly expressed in cerebellar Purkinje cells (PCs). The Cacna2d2du2J mutation results in a two base-pair deletion in the coding region and a complete loss of α2δ-2 protein. Here we show that du2J/du2J mice have a 30% reduction in somatic calcium current, and a marked fall in the spontaneous PC firing rate at 22°C, accompanied by a decrease in firing regularity, which is not affected by blocking synaptic input to PCs. At 34°C du2J/du2J PCs show no spontaneous intrinsic activity. Du2J/du2J mice also have alterations in the cerebellar expression of several genes related to PC function. At P21 there is an elevation of tyrosine hydroxylase mRNA and a reduction in tenascin-C gene expression. Although du2J/+ mice have a marked reduction in α2δ-2 protein, they show no fall in PC somatic calcium currents or increase in cerebellar tryrosine hydroxylase gene expression. However, du2J/+ PCs do exhibit a significant reduction in firing rate, correlating with the reduction in α2δ-2. A hypothesis for future study is that effects on gene expression occur as a result of a reduction in somatic calcium currents, whereas effects on PC firing occur as a long-term result of loss of α2δ-2 and/or a reduction in calcium currents and calcium-dependent processes in regions other than the soma. PMID:17135419

  15. The ducky(2J) mutation in Cacna2d2 results in reduced spontaneous Purkinje cell activity and altered gene expression.

    Science.gov (United States)

    Donato, Roberta; Page, Karen M; Koch, Dietlind; Nieto-Rostro, Manuela; Foucault, Isabelle; Davies, Anthony; Wilkinson, Tonia; Rees, Michele; Edwards, Frances A; Dolphin, Annette C

    2006-11-29

    The mouse mutant ducky and its allele ducky(2J) represent a model for absence epilepsy characterized by spike-wave seizures and cerebellar ataxia. These mice have mutations in Cacna2d2, which encodes the alpha2delta-2 calcium channel subunit. Of relevance to the ataxic phenotype, alpha2delta-2 mRNA is strongly expressed in cerebellar Purkinje cells (PCs). The Cacna2d2(du2J) mutation results in a 2 bp deletion in the coding region and a complete loss of alpha2delta-2 protein. Here we show that du(2J)/du(2J) mice have a 30% reduction in somatic calcium current and a marked fall in the spontaneous PC firing rate at 22 degrees C, accompanied by a decrease in firing regularity, which is not affected by blocking synaptic input to PCs. At 34 degrees C, du(2J)/du(2J) PCs show no spontaneous intrinsic activity. Du(2J)/du(2J) mice also have alterations in the cerebellar expression of several genes related to PC function. At postnatal day 21, there is an elevation of tyrosine hydroxylase mRNA and a reduction in tenascin-C gene expression. Although du(2J)/+ mice have a marked reduction in alpha2delta-2 protein, they show no fall in PC somatic calcium currents or increase in cerebellar tyrosine hydroxylase gene expression. However, du(2J)/+ PCs do exhibit a significant reduction in firing rate, correlating with the reduction in alpha2delta-2. A hypothesis for future study is that effects on gene expression occur as a result of a reduction in somatic calcium currents, whereas effects on PC firing occur as a long-term result of loss of alpha2delta-2 and/or a reduction in calcium currents and calcium-dependent processes in regions other than the soma.

  16. Fire Ant Bites

    Science.gov (United States)

    ... Favorite Name: Category: Share: Yes No, Keep Private Fire Ant Bites Share | Fire ants are aggressive, venomous insects that have pinching ... across the United States, even into Puerto Rico. Fire ant stings usually occur on the feet or ...

  17. Fire safety at home

    Science.gov (United States)

    ... over the smoke alarm as needed. Using a fire extinguisher can put out a small fire to keep it from getting out of control. Tips for use include: Keep fire extinguishers in handy locations, at least one on ...

  18. Crown Fire Potential

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — Crown fire potential was modeled using FlamMap, an interagency fire behavior mapping and analysis program that computes potential fire behavior characteristics. The...

  19. National Fire Protection Association

    Science.gov (United States)

    ... closed NFPA Journal® NFPA Journal® Update (newsletter) Fire Technology ... die from American home fires, and another 13,000 are injured each year. This is the story of fire that the statistics won't show ...

  20. Current Status of Fire Risk Assessment in Germany

    International Nuclear Information System (INIS)

    Berg, H. P.

    2002-01-01

    The approach for fire risk assessment to be applied within periodic safety reviews of nuclear power plants in Germany starts with a screening process providing critical fire zones in which a fully developed fire has the potential to both cause an initiating event and impair the function of at least one component or system critical to safety. The second step is to perform a quantitative analysis. For that purpose, a standard event tree has been developed with elements for fire initiation, ventilation of the room, fire detection, fire suppression, and fire propagation. This standard event tree has to be adapted to each critical fire zone or room. In a final step, the fire induced frequency of initiating events, the main contributors and the calculated hazard state frequency for the fire event are determined. In order to perform a quantitative fire risk assessment, a basic data base must be established which should, e.g., include initiating frequencies, reliability data for all fire protection measures, fire barriers, etc. Detailed plant-specific information is needed on ignition sources, detection and extinguishing systems, manual fire fighting, stationary fire suppression systems. As one contributor to fire specific PSA input data, reliability data for the active fire protection measures are required for the application in the fire specific event tree analysis. These data needed to be estimated are unavailabilities per demand or failure rates per hour of plant operation for those components or systems belonging to the active fire protection means. The data on potential failures or unavailabilities per demand of the respective fire protection measures were gained from the plant specific documentation of inspection and maintenance. The assessment whether the detected findings are estimated as failures or only as deficiencies or deteriorations requires a deep insight in the plant specific operating conditions for the fire protection means and needs careful engineering

  1. BK channels regulate spontaneous action potential rhythmicity in the suprachiasmatic nucleus.

    Directory of Open Access Journals (Sweden)

    Jack Kent

    Full Text Available BACKGROUND: Circadian ( approximately 24 hr rhythms are generated by the central pacemaker localized to the suprachiasmatic nucleus (SCN of the hypothalamus. Although the basis for intrinsic rhythmicity is generally understood to rely on transcription factors encoded by "clock genes", less is known about the daily regulation of SCN neuronal activity patterns that communicate a circadian time signal to downstream behaviors and physiological systems. Action potentials in the SCN are necessary for the circadian timing of behavior, and individual SCN neurons modulate their spontaneous firing rate (SFR over the daily cycle, suggesting that the circadian patterning of neuronal activity is necessary for normal behavioral rhythm expression. The BK K(+ channel plays an important role in suppressing spontaneous firing at night in SCN neurons. Deletion of the Kcnma1 gene, encoding the BK channel, causes degradation of circadian behavioral and physiological rhythms. METHODOLOGY/PRINCIPAL FINDINGS: To test the hypothesis that loss of robust behavioral rhythmicity in Kcnma1(-/- mice is due to the disruption of SFR rhythms in the SCN, we used multi-electrode arrays to record extracellular action potentials from acute wild-type (WT and Kcnma1(-/- slices. Patterns of activity in the SCN were tracked simultaneously for up to 3 days, and the phase, period, and synchronization of SFR rhythms were examined. Loss of BK channels increased arrhythmicity but also altered the amplitude and period of rhythmic activity. Unexpectedly, Kcnma1(-/- SCNs showed increased variability in the timing of the daily SFR peak. CONCLUSIONS/SIGNIFICANCE: These results suggest that BK channels regulate multiple aspects of the circadian patterning of neuronal activity in the SCN. In addition, these data illustrate the characteristics of a disrupted SCN rhythm downstream of clock gene-mediated timekeeping and its relationship to behavioral rhythms.

  2. FIRE CHARACTERISTICS FOR ADVANCED MODELLING OF FIRES

    OpenAIRE

    Otto Dvořák

    2016-01-01

    This paper summarizes the material and fire properties of solid flammable/combustible materials /substances /products, which are used as inputs for the computer numerical fire models. At the same time it gives the test standards for their determination.

  3. The Autonomic Nervous System Regulates the Heart Rate through cAMP-PKA Dependent and Independent Coupled-Clock Pacemaker Cell Mechanisms.

    Science.gov (United States)

    Behar, Joachim; Ganesan, Ambhighainath; Zhang, Jin; Yaniv, Yael

    2016-01-01

    Sinoatrial nodal cells (SANCs) generate spontaneous action potentials (APs) that control the cardiac rate. The brain modulates SANC automaticity, via the autonomic nervous system, by stimulating membrane receptors that activate (adrenergic) or inactivate (cholinergic) adenylyl cyclase (AC). However, these opposing afferents are not simply additive. We showed that activation of adrenergic signaling increases AC-cAMP/PKA signaling, which mediates the increase in the SANC AP firing rate (i.e., positive chronotropic modulation). However, there is a limited understanding of the underlying internal pacemaker mechanisms involved in the crosstalk between cholinergic receptors and the decrease in the SANC AP firing rate (i.e., negative chronotropic modulation). We hypothesize that changes in AC-cAMP/PKA activity are crucial for mediating either decrease or increase in the AP firing rate and that the change in rate is due to both internal and membrane mechanisms. In cultured adult rabbit pacemaker cells infected with an adenovirus expressing the FRET sensor AKAR3, PKA activity and AP firing rate were tightly linked in response to either adrenergic receptor stimulation (by isoproterenol, ISO) or cholinergic stimulation (by carbachol, CCh). To identify the main molecular targets that mediate between PKA signaling and pacemaker function, we developed a mechanistic computational model. The model includes a description of autonomic-nervous receptors, post- translation signaling cascades, membrane molecules, and internal pacemaker mechanisms. Yielding results similar to those of the experiments, the model simulations faithfully reproduce the changes in AP firing rate in response to CCh or ISO or a combination of both (i.e., accentuated antagonism). Eliminating AC-cAMP-PKA signaling abolished the core effect of autonomic receptor stimulation on the AP firing rate. Specifically, disabling the phospholamban modulation of the SERCA activity resulted in a significantly reduced effect

  4. Spontaneous Intracranial Hypotension

    International Nuclear Information System (INIS)

    Joash, Dr.

    2015-01-01

    Epidemiology is not only rare but an important cause of new daily persistent headaches among young & middle age individuals. The Etiology & Pathogenesis is generally caused by spinal CSF leak. Precise cause remains largely unknown, underlying structural weakness of spinal meninges is suspected. There are several MR Signs of Intracranial Hypotension that include:- diffuse pachymeningeal (dural) enhancement; bilateral subdural, effusion/hematomas; Downward displacement of brain; enlargement of pituitary gland; Engorgement of dural venous sinuses; prominence of spinal epidural venous plexus and Venous sinus thrombosis & isolated cortical vein thrombosis. The sum of volumes of intracranial blood, CSF & cerebral tissue must remain constant in an intact cranium. Treatment in Many cases can be resolved spontaneously or by use Conservative approach that include bed rest, oral hydration, caffeine intake and use of abdominal binder. Imaging Modalities for Detection of CSF leakage include CT myelography, Radioisotope cisternography, MR myelography, MR imaging and Intrathecal Gd-enhanced MR

  5. Spontaneous wave packet reduction

    International Nuclear Information System (INIS)

    Ghirardi, G.C.

    1994-06-01

    There are taken into account the main conceptual difficulties met by standard quantum mechanics in dealing with physical processes involving macroscopic system. It is stressed how J.A.Wheeler's remarks and lucid analysis have been relevant to pinpoint and to bring to its extreme consequences the puzzling aspects of quantum phenomena. It is shown how the recently proposed models of spontaneous dynamical reduction represent a consistent way to overcome the conceptual difficulties of the standard theory. Obviously, many nontrivial problems remain open, the first and more relevant one being that of generalizing the model theories considered to the relativistic case. This is the challenge of the dynamical reduction program. 43 refs, 2 figs

  6. The impact of state fire safe cigarette policies on fire fatalities, injuries, and incidents.

    Science.gov (United States)

    Folz, David H; Shults, Chris

    Cigarettes are a leading cause of civilian deaths in home fires. Over the last decade, state fire service leaders and allied interest groups succeeded in persuading state lawmakers to require manufacturers to sell only low-ignition strength or "fire safe" cigarettes as a strategy to reduce these fatalities and the injuries and losses that stem from them. This article examines whether the states' fire safe cigarette laws actually helped to save lives, prevent injuries, and reduce the incidence of home fires ignited by cigarettes left unattended by smokers. Controlling for the effects of key demographic, social, economic, and housing variables, this study finds that the states' fire-safe cigarette policies had significant impacts on reducing the rate of smoking-related civilian fire deaths and the incidence of fires started by tobacco products. The findings also suggest that the states' fire safe cigarette policies may have helped to reduce the rate of smoking-related fire injuries. The study shows that collective actions by leaders in the fire service across the states can result in meaningful policy change that protects lives and advances public safety even when a political consensus for action is absent at the national level.

  7. Effect of fire season, fire frequency, rainfall and management on fire intensity in savanna vegetation in South Africa

    CSIR Research Space (South Africa)

    Govender, N

    2006-08-01

    Full Text Available in the Kruger National Park, South Africa, by documenting fuel loads, fuel moisture contents, rates of fire spread and the heat yields of fuel in 956 experimental plot burns over 21 years. 3. Individual fires were conducted in five different months (February...

  8. Corrosion and Materials Performance in biomass fired and co-fired power plants

    DEFF Research Database (Denmark)

    Montgomery, Melanie; Larsen, OH; Biede, O

    2003-01-01

    not previously encountered in coal-fired power plants. The type of corrosion attack can be directly ascribed to the composition of the deposit and the metal surface temperature. In woodchip boilers, a similar corrosion rate and corrosion mechanism has on some occasions been observed. Co-firing of straw (10...... and 20% energy basis) with coal has shown corrosion rates lower than those in straw-fired plants. With both 10 and 20% straw, no chlorine corrosion was seen. This paper will describe the results from in situ investigations undertaken in Denmark on high temperature corrosion in biomass fired plants....... Results from 100% straw-firing, woodchip and co-firing of straw with coal will be reported. The corrosion mechanisms observed are summarized and the corrosion rates for 18-8 type stainless steels are compared....

  9. Self energy QED: Multipole spontaneous emission

    International Nuclear Information System (INIS)

    Salamin, Y.I.

    1990-08-01

    Within the context of Barut's self-field approach, we write the exact expression of the spontaneous atomic decay rate (Phys. Rev. A37, 2284 (1988)), in the long wavelength approximation, in terms of electric- and magnetic-like multipole contributions which are related to the matrix elements of the transition charge and current distributions of the relativistic electron. A number of features of these expressions are discussed and their generalization to interacting composite systems is also pointed out. (author). 8 refs

  10. Fire and fire ecology: Concepts and principles

    Science.gov (United States)

    Mark A. Cochrane; Kevin C. Ryan

    2009-01-01

    Fire has been central to terrestrial life ever since early anaerobic microorganisms poisoned the atmosphere with oxygen and multicellular plant life moved onto land. The combination of fuels, oxygen, and heat gave birth to fire on Earth. Fire is not just another evolutionary challenge that life needed to overcome, it is, in fact, a core ecological process across much...

  11. Unintentional carbon monoxide poisoning hospitalization and emergency department counts and rates by county, year, and fire-relatedness among California residents,2000-2007

    Data.gov (United States)

    California Environmental Health Tracking Program — This dataset contains case counts, rates, and confidence intervals of unintentional carbon monoxide poisoning (CO) inpatient hospitalizations and emergency...

  12. Spontaneous compactification to homogeneous spaces

    International Nuclear Information System (INIS)

    Mourao, J.M.

    1988-01-01

    The spontaneous compactification of extra dimensions to compact homogeneous spaces is studied. The methods developed within the framework of coset space dimensional reduction scheme and the most general form of invariant metrics are used to find solutions of spontaneous compactification equations

  13. Screening for spontaneous preterm birth

    NARCIS (Netherlands)

    van Os, M.A.; van Dam, A.J.E.M.

    2015-01-01

    Preterm birth is the most important cause of perinatal morbidity and mortality worldwide. In this thesis studies on spontaneous preterm birth are presented. The main objective was to investigate the predictive capacity of mid-trimester cervical length measurement for spontaneous preterm birth in a

  14. Theoretical-probability evaluation of the fire hazard of coal accumulations

    Energy Technology Data Exchange (ETDEWEB)

    Sikora, F F

    1978-01-01

    An evaluation is suggested for the fire hazard of coal accumulations, based on determining the probability of an endogenic fire. This probability is computed by using the statistical characteristics of the temperature distribution of spontaneous heating in large accumulations, and the criteria of Gluzberg's fire hazard that is determined by the coal's physico-chemical properties, oxygen concentration, and the size of the accumulations. 4 references.

  15. Spontaneous Pneumomediastinum: Hamman Syndrome

    Directory of Open Access Journals (Sweden)

    Tushank Chadha, BS

    2018-04-01

    significant fat stranding. The image also showed an intraluminal stent traversing the gastric antrum and gastric pylorus with no indication of obstruction. Circumferential mural thickening of the gastric antrum and body were consistent with the patient’s history of gastric adenocarcinoma. The shotty perigastric lymph nodes with associated fat stranding, along the greater curvature of the distal gastric body suggested local regional nodal metastases and possible peritoneal carcinomatosis. The thoracic CT scans showed extensive pneumomediastinum that tracked into the soft tissues of the neck, which given the history of vomiting also raised concern for esophageal perforation. There was still no evidence of mediastinal abscess or fat stranding. Additionally, a left subclavian vein port catheter, which terminates with tip at the cavoatrial junction of the superior vena cava can also be seen on the image. Discussion: Spontaneous Pneumomediastinum, also known as Hamman syndrome, is defined by the uncommon incidence of free air in the mediastinum due to the bursting of alveoli, as a result of extended spells of shouting, coughing, or vomiting.1,2 The condition is diagnosed when a clear cause (aerodigestive rupture, barotrauma, infection secondary to gas-forming organisms3 for pneumomediastinum cannot be clearly identified on diagnostic studies. Macklin and Macklin were the first to note the pathogenesis of the syndrome and explained that the common denominator to spontaneous pneumomediastinum was that increased alveolar pressure leads to alveolar rupture.3 Common clinical findings for spontaneous pneumomediastinum include: chest pain, dyspnea, cough, and emesis.4 The condition is not always readily recognized on initial presentation in part for its rare incidence, estimated to be approximately 1 in every 44,500 ED patients3and also because of the non-specific presenting symptoms. For this patient, there was no clear singular cause, and therefore she received care for spontaneous

  16. Fire PRA requantification studies. Final report

    International Nuclear Information System (INIS)

    Parkinson, W.

    1993-03-01

    This report describes the requantification of two existing fire probabilistic risk assessments (PRAs) using a fire PRA method and data that are being developed by the Electric Power Research Institute (EPRI). The two existing studies are the Seabrook Station Probabilistic Safety Assessment that was made in 1983 and the 1989 NUREG-1150 analysis of the Peach Bottom Plant. Except for the fire methods and data, the original assumptions were used. The results from the requantification show that there were excessive conservatisms in the original studies. The principal reason for a hundredfold reduction in the Peach Bottom core- damage frequency is the determination that no electrical cabinet fire in a switchgear room would damage both offsite power feeds. Past studies often overestimated the heat release from electrical cabinet fires. EPRI's electrical cabinet heat release rates are based on tests that were conducted for Sandia's fire research program. The rates are supported by the experience in the EPRI Fire Events Database for U.S. nuclear plants. Test data and fire event experience also removed excessive conservatisms in the Peach Bottom control and cable spreading rooms, and the Seabrook primary component cooling pump, turbine building relay and cable spreading rooms. The EPRI fire PRA method and data will show that there are excessive conservatisms in studies that were made for many plants and can benefit them accordingly

  17. The sodium fire tests performed in the FAUNA facility on up to 12m2 fire areas

    International Nuclear Information System (INIS)

    Cherdron, W.; Jordan, S.

    1983-08-01

    The FAUNA test facility started operation in 1979. It serves to investigate large area sodium fires in closed containments and to study the generation, behaviour and removal of sodium fire aerosols. In this report, the experimental results of the 6 sodium pool fires are described which were performed with up to 500 kg of sodium in fire pans of 2 m 2 , 5 m 2 and 12 m 2 surface area, respectively. Both, the thermodynamic data and the data of the reaction kinetics of the fires were determined. In addition, the behaviour of the released aerosols during and after the fire was studied. On the basis of measurements of the temperature profiles at various levels above the fire areas it was shown that the convective flows above fire areas of different sizes in closed containments differ markedly and, obviously, exert an influence on the development of the fire and the release of particles. Whilst in rather small fires the gas above the pan rises as in a chimney and flows back on the walls, no chimney effect can be observed in a large pool fire. In rather large fires higher burning rates and aerosol release rates were observed. Some meters above the fire area temperatures around 300-400 0 C, temporarily even up to 700 0 C, were measured. The tests F5 and F6 were performed above all to observe the fire behaviour in terms of thermodynamics and reaction kinetics in a fully closed containment. (orig./RW) [de

  18. Using satellite fire detection to calibrate components of the fire weather index system in Malaysia and Indonesia.

    Science.gov (United States)

    Dymond, Caren C; Field, Robert D; Roswintiarti, Orbita; Guswanto

    2005-04-01

    Vegetation fires have become an increasing problem in tropical environments as a consequence of socioeconomic pressures and subsequent land-use change. In response, fire management systems are being developed. This study set out to determine the relationships between two aspects of the fire problems in western Indonesia and Malaysia, and two components of the Canadian Forest Fire Weather Index System. The study resulted in a new method for calibrating components of fire danger rating systems based on satellite fire detection (hotspot) data. Once the climate was accounted for, a problematic number of fires were related to high levels of the Fine Fuel Moisture Code. The relationship between climate, Fine Fuel Moisture Code, and hotspot occurrence was used to calibrate Fire Occurrence Potential classes where low accounted for 3% of the fires from 1994 to 2000, moderate accounted for 25%, high 26%, and extreme 38%. Further problems arise when there are large clusters of fires burning that may consume valuable land or produce local smoke pollution. Once the climate was taken into account, the hotspot load (number and size of clusters of hotspots) was related to the Fire Weather Index. The relationship between climate, Fire Weather Index, and hotspot load was used to calibrate Fire Load Potential classes. Low Fire Load Potential conditions (75% of an average year) corresponded with 24% of the hotspot clusters, which had an average size of 30% of the largest cluster. In contrast, extreme Fire Load Potential conditions (1% of an average year) corresponded with 30% of the hotspot clusters, which had an average size of 58% of the maximum. Both Fire Occurrence Potential and Fire Load Potential calibrations were successfully validated with data from 2001. This study showed that when ground measurements are not available, fire statistics derived from satellite fire detection archives can be reliably used for calibration. More importantly, as a result of this work, Malaysia and

  19. Fires, ecological effects of

    Science.gov (United States)

    W. J. Bond; Robert Keane

    2017-01-01

    Fire is both a natural and anthropogenic disturbance influencing the distribution, structure, and functioning of terrestrial ecosystems around the world. Many plants and animals depend on fire for their continued existence. Others species, such as rainforest plants species, are extremely intolerant of burning and need protection from fire. The properties of a fire...

  20. Distinct spontaneous shrinkage of a sporadic vestibular schwannoma

    DEFF Research Database (Denmark)

    Huang, Xiaowen; Cayé-Thomasen, Per; Stangerup, Sven-Eric

    2013-01-01

    on "shrinkage" or "negative growth" or "regression" or "involution" of the tumor were selected, and the contents on the rate, extent and mechanism of spontaneous tumor shrinkage were extracted and reviewed. The reported rate of spontaneous shrinkage of vestibular schwannoma is 5-10% of patients managed......We present a case with outspoken spontaneous vestibular schwannoma shrinkage and review the related literature. The patient was initially diagnosed with a left-sided, intrameatal vestibular schwannoma, which subsequently grew into the cerebello-pontine angle (CPA), followed by total shrinkage...... of the CPA component without any intervention over a 12-year observation period. The literature on spontaneous tumor shrinkage was retrieved by searching the subject terms "vestibular schwannoma, conservative management" in PubMed/MEDLINE database, without a time limit. Of the published data, the articles...

  1. Spontaneous lateral temporal encephalocele.

    Science.gov (United States)

    Tuncbilek, Gokhan; Calis, Mert; Akalan, Nejat

    2013-01-01

    A spontaneous encephalocele is one that develops either because of embryological maldevelopment or from a poorly understood postnatal process that permits brain herniation to occur. We here report a rare case of lateral temporal encephalocele extending to the infratemporal fossa under the zygomatic arch. At birth, the infant was noted to have a large cystic mass in the right side of the face. After being operated on initially in another center in the newborn period, the patient was referred to our clinic with a diagnosis of temporal encephalocele. He was 6 months old at the time of admission. Computerized tomography scan and magnetic resonance imaging studies revealed a 8 × 9 cm fluid-filled, multiloculated cystic mass at the right infratemporal fossa. No intracranial pathology or connection is seen. The patient was operated on to reduce the distortion effect of the growing mass. The histopathological examination of the sac revealed well-differentiated mature glial tissue stained with glial fibrillary acid protein. This rare clinical presentation of encephaloceles should be taken into consideration during the evaluation of the lateral facial masses in the infancy period, and possible intracranial connection should be ruled out before surgery to avoid complications.

  2. Spontaneous intracranial hypotension

    International Nuclear Information System (INIS)

    Haritanti, A.; Karacostas, D.; Drevelengas, A.; Kanellopoulos, V.; Paraskevopoulou, E.; Lefkopoulos, A.; Economou, I.; Dimitriadis, A.S.

    2009-01-01

    Spontaneous intracranial hypotension (SIH) is an uncommon but increasingly recognized syndrome. Orthostatic headache with typical findings on magnetic resonance imaging (MRI) are the key to diagnosis. Delayed diagnosis of this condition may subject patients to unnecessary procedures and prolong morbidity. We describe six patients with SIH and outline the important clinical and neuroimaging findings. They were all relatively young, 20-54 years old, with clearly orthostatic headache, minimal neurological signs (only abducent nerve paresis in two) and diffuse pachymeningeal gadolinium enhancement on brain MRI, while two of them presented subdural hygromas. Spinal MRI was helpful in detecting a cervical cerebrospinal fluid leak in three patients and dilatation of the vertebral venous plexus with extradural fluid collection in another. Conservative management resulted in rapid resolution of symptoms in five patients (10 days-3 weeks) and in one who developed cerebral venous sinus thrombosis, the condition resolved in 2 months. However, this rapid clinical improvement was not accompanied by an analogous regression of the brain MR findings that persisted on a longer follow-up. Along with recent literature data, our patients further point out that SIH, to be correctly diagnosed, necessitates increased alertness by the attending physician, in the evaluation of headaches

  3. Genetics Home Reference: primary spontaneous pneumothorax

    Science.gov (United States)

    ... Home Health Conditions Primary spontaneous pneumothorax Primary spontaneous pneumothorax Printable PDF Open All Close All Enable Javascript ... view the expand/collapse boxes. Description Primary spontaneous pneumothorax is an abnormal accumulation of air in the ...

  4. VBAC In Women Undergoing IOL With Dinoprostone Versus Spontaneous Labor

    OpenAIRE

    Alves, João; Vilhena, Cristina; Tomás, Cláudia; Antunes, Isabel Lobo; Metello, José; Natário, Isabel; Puga, Marco; Casal, Ester

    2015-01-01

    Sem PDF OBJECTIVE: To compare the rate of vaginal birth in women attempting vaginal birth after caesarean delivery (VBAC) through labour induction with dinoprostone versus a trial of spontaneous labour. METHODS: A 10-year retrospective cohort study in a tertiary care hospital of women with one prior caesarean delivery. Women who attempted VBAC with labour induction with dinoprostone were compared with women undergoing spontaneous labour. Logistic regression analyses were performed to asses...

  5. Teaching Spontaneous Responses to Young Children With Autism

    OpenAIRE

    Jones, Emily A; Feeley, Kathleen M; Takacs, Jennifer

    2007-01-01

    Using a multiple probe design across responses, we demonstrated the effectiveness of intensive intervention in establishing spontaneous verbal responses to 2 3-year-old children with autism with generalization to novel settings involving novel persons. Intervention involved discrete-trial instruction (i.e., repeated instructional opportunities presented in close proximity to high rates of reinforcement), specific prompts, and error correction. Spontaneous responses were defined as specific ve...

  6. Building 431 fire tests

    International Nuclear Information System (INIS)

    Alvares, N.J.; Beason, D.G.; Ford, H.W.; Magee, M.W.

    1977-01-01

    An extensive discussion of considerations for fire protection in the LLL mirror fusion test facility (MFTF) is presented. Because of the large volume and high bays of the building, sufficient data on fire detection is unavailable. Results of fire detection tests using controlled fire sources in the building are presented. Extensive data concerning the behavior of the building atmosphere are included. Candidate fire detection instrumentation and extinguishing systems for use in the building are briefly reviewed

  7. Fire-Walking

    Science.gov (United States)

    Willey, David

    2010-01-01

    This article gives a brief history of fire-walking and then deals with the physics behind fire-walking. The author has performed approximately 50 fire-walks, took the data for the world's hottest fire-walk and was, at one time, a world record holder for the longest fire-walk (www.dwilley.com/HDATLTW/Record_Making_Firewalks.html). He currently…

  8. Fire, safety and ventilation

    Energy Technology Data Exchange (ETDEWEB)

    Hindle, D.

    1999-02-01

    Correct ventilation in tunnel environments is vital for the comfort and safety of the people passing through. This article gives details of products from several manufacturers of safety rescue and fire fighting equipment, fire and fume detection equipment, special fire resistant materials, fire resistant hydraulic oils and fire dampers, and ventilation systems. Company addresses and fax numbers are supplied. 4 refs., 5 tabs., 10 photos.

  9. Fire, humans and landscape. Is there a connection?

    Science.gov (United States)

    Valese, Eva; Ascoli, Davide; Conedera, Marco; Held, Alex

    2013-04-01

    Fire evolved on the earth under the direct influence of climate and the accumulation of burnable biomass at various times and spatial scales. As a result, fire regimes depend not only on climatic and biological factors, but also greatly reflect the cultural background of how people do manage ecosystems and fire. A new awareness among scientists and managers has been rising about the ecological role of fire and the necessity to understand its past natural and cultural dynamics in different ecosystems, in order to preserve present ecosystem functionality and minimize management costs and negative impacts. As a consequence we assisted in the last decades to a general shift from the fire control to the fire management approach, where fire prevention, fire danger rating, fire ecology, fire pre-suppression and suppression strategies are fully integrated in the landscape management. Nowadays, a large number of authors recognize that a total suppression strategy, as the one adopted during last decades, leads to a fire paradox: the more we fight for putting out all fires, the more extreme events occur and cause long term damages. The aim of this review is to provide a state of art about the connection between fire, humans and landscape, along time and space. Negative and positive impacts on ecosystem services and values are put in evidence, as well as their incidence on human aptitude to fire use as to fire suppression. In order to capture a consistent fragment of fire history, palaeofires and related palynological studies are considered. They enable a valuable, even if partial, look at the millenary fire regime. Actual strategies and future directions are described in order to show what are the alternatives for living with fire, since removing completely this disturbance from earth is not a option, nor feasible neither advisable. Examples from the world, in particular from the Alps and the Mediterranean basin, are shown for better illustrating the signature of

  10. Aqueous clay suspensions stabilized by alginate fluid gels for coal spontaneous combustion prevention and control.

    Science.gov (United States)

    Qin, Botao; Ma, Dong; Li, Fanglei; Li, Yong

    2017-11-01

    We have developed aqueous clay suspensions stabilized by alginate fluid gels (AFG) for coal spontaneous combustion prevention and control. Specially, this study aimed to characterize the effect of AFG on the microstructure, static and dynamic stability, and coal fire inhibition performances of the prepared AFG-stabilized clay suspensions. Compared with aqueous clay suspensions, the AFG-stabilized clay suspensions manifest high static and dynamic stability, which can be ascribed to the formation of a robust three-dimensional gel network by AFG. The coal acceleration oxidation experimental results show that the prepared AFG-stabilized clay suspensions can improve the coal thermal stability and effectively inhibit the coal spontaneous oxidation process by increasing crossing point temperature (CPT) and reducing CO emission. The prepared low-cost and nontoxic AFG-stabilized clay suspensions, exhibiting excellent coal fire extinguishing performances, indicate great application potentials in coal spontaneous combustion prevention and control.

  11. Fire analog: a comparison between fire plumes and energy center cooling tower plumes

    Energy Technology Data Exchange (ETDEWEB)

    Orgill, M.M.

    1977-10-01

    Thermal plumes or convection columns associated with large fires are compared to thermal plumes from cooling towers and proposed energy centers to evaluate the fire analog concept. Energy release rates of mass fires are generally larger than for single or small groups of cooling towers but are comparable to proposed large energy centers. However, significant physical differences exist between cooling tower plumes and fire plumes. Cooling tower plumes are generally dominated by ambient wind, stability and turbulence conditions. Fire plumes, depending on burning rates and other factors, can transform into convective columns which may cause the fire behavior to become more violent. This transformation can cause strong inflow winds and updrafts, turbulence and concentrated vortices. Intense convective columns may interact with ambient winds to create significant downwind effects such as wakes and Karman vortex streets. These characteristics have not been observed with cooling tower plumes to date. The differences in physical characteristics between cooling tower and fire plumes makes the fire analog concept very questionable even though the approximate energy requirements appear to be satisfied in case of large energy centers. Additional research is suggested in studying the upper-level plume characteristics of small experimental fires so this information can be correlated with similar data from cooling towers. Numerical simulation of fires and proposed multiple cooling tower systems could also provide comparative data.

  12. Ziprasidone-induced spontaneous orgasm.

    Science.gov (United States)

    Boora, K; Chiappone, K; Dubovsky, S; Xu, J

    2010-06-01

    Neuroleptic treatment in schizophrenic patients has been associated with sexual dysfunction, including impotence and decreased libido. Spontaneous ejaculation without sexual arousal during typical antipsychotic treatment is a rare condition that has been described with zuclopentixol, trifluoperazine, and thiothixene. Here, we are reporting a case of spontaneous orgasm with ziprasidone in a bipolar patient. This patient began to repeatedly experience spontaneous sexual arousal and orgasm, which she had never experienced in the past. Ziprasidone might be causing an increase in sexual orgasm by 5-HT2 receptor antagonism, which preclinical evidence suggests that it facilitates dopamine release in the cortex.

  13. Control technique of spontaneous combustion in fully mechan ized stope during period of end caving under complex mining influence

    Science.gov (United States)

    Yuan, Benqing

    2018-01-01

    In view of the phenomenon of spontaneous combustion of coal seam occurring during the period of end caving under complex mining conditions, taking the 1116 (3) stope of Guqiao mine as the object of study, the causes of spontaneous combustion during the period of end caving are analyzed, according to the specific geological conditions of the stope to develop corresponding fire prevention measures, including the reduction of air supply and air leakage in goaf, reduce the amount of coal left, reasonable drainage, nitrogen injection for spontaneous combustion prevention, grouting for spontaneous combustion prevention and permanent closure, fundamentally eliminates the potential for spontaneous combustion during the period of 1116(3) stope end caving. The engineering practice shows that this kind of measure has reference value for the prevention and control of spontaneous combustion during the period of stope end caving.

  14. Liquid nitrogen fire extinguishing system test report

    International Nuclear Information System (INIS)

    Beidelman, J.A.

    1972-01-01

    The objective of this test series was to demonstrate the feasibility of using liquid nitrogen as a fire-extinguishing agent for certain types of metal fires. It was intended to provide data and experience appropriate to the design of a second series which will test the applicability of this technique to plutonium fires and which will develop more detailed operating information and permit more precise measurement of test parameters-oxygen depletion rates and equilibrium concentrations, temperature effects, and nitrogen pressures, flow rates, spray methods and patterns, etc. The test series was directed specifically toward extinguishment of metal fires occurring in well-confined areas and was not intended to be representative of any larger classification. Fires of several types were tested, e.g., magnesium, mixed magnesium and zirconium, sodium and cerium

  15. Spontaneous light emission from fibers in MINOS

    International Nuclear Information System (INIS)

    Avvakumov, S.; Barrett, W.L.; Belias, T.; Bower, C.; Erwin, A.; Kordosky, M.; Lang, K.; Lee, R.; Liu, J.; Miller, W.; Mualem, L.; Nichol, R.; Nelson, J.; Pearce, G.; Proga, M.; Rebel, B.; Ruddick, K.; Smith, C.; Thomas, J.; Vahle, P.; Webb, R.

    2005-01-01

    We report on the observation and measurements of unexpected background rates in the MINOS Far Detector. The noise level at the Far Detector is significantly greater than that expected from natural radioactivity and intrinsic photomultiplier dark current. We have conducted a series of additional tests which demonstrate that the excess rate is caused by spontaneous light emission in the wavelength-shifting fibers, which are used to read out signals from scintillator strips. This noise due to fibers exhibits an exponential fall off with time with a decay time constant of the order of 100 days

  16. Characterisation of open-door electrical cabinet fires in compartments

    Energy Technology Data Exchange (ETDEWEB)

    Coutin, M., E-mail: mickael.coutin@irsn.fr; Plumecocq, W.; Zavaleta, P.; Audouin, L.

    2015-05-15

    Highlights: • Heat release rate of electrical cabinet fire source in a vitiated atmosphere. • Experimental database for proper validation the combustible modelling, taking into account the oxygen depletion in an enclosure. • New model for complex fire source. - Abstract: The study of electrical fires is a major concern for fire safety in the industry and more particularly for fire safety in nuclear facilities. To investigate this topic, IRSN conducted a large number of real-scale experiments involving open-door electrical cabinets burning firstly under a calorimetric hood and then inside a mechanically-ventilated compartment. The main challenges are to determine accurately the heat release rate of such a complex fire source in a vitiated atmosphere and to provide an experimental database for validating properly the combustible modelling, taking into account the oxygen depletion in an enclosure. After providing a detailed description of the fire scenarios and of the experimental apparatus, this paper focuses on the characteristic stages of the cabinet fire development, essentially based on the heat release rate time evolution of the fire. The effects of the confinement, of the outlet branch location, of the ventilation management and of the fire barrier on the fire source were then investigated. The reproducibility of electrical cabinet fires is also studied. A new model for complex fire source (applied in this study for open-door electrical cabinet fires) was then developed. This model was introduced in the zone code SYLVIA and the major features of the compartment fire experiments, such as characteristic heat release rate with effect of oxygen depletion and over-pressure peak were then calculated with a rather good agreement for this complex fire source (i.e. electrical cabinet)

  17. Behavioral Modulation by Spontaneous Activity of Dopamine Neurons

    Directory of Open Access Journals (Sweden)

    Toshiharu Ichinose

    2017-12-01

    Full Text Available Dopamine modulates a variety of animal behaviors that range from sleep and learning to courtship and aggression. Besides its well-known phasic firing to natural reward, a substantial number of dopamine neurons (DANs are known to exhibit ongoing intrinsic activity in the absence of an external stimulus. While accumulating evidence points at functional implications for these intrinsic “spontaneous activities” of DANs in cognitive processes, a causal link to behavior and its underlying mechanisms has yet to be elucidated. Recent physiological studies in the model organism Drosophila melanogaster have uncovered that DANs in the fly brain are also spontaneously active, and that this activity reflects the behavioral/internal states of the animal. Strikingly, genetic manipulation of basal DAN activity resulted in behavioral alterations in the fly, providing critical evidence that links spontaneous DAN activity to behavioral states. Furthermore, circuit-level analyses have started to reveal cellular and molecular mechanisms that mediate or regulate spontaneous DAN activity. Through reviewing recent findings in different animals with the major focus on flies, we will discuss potential roles of this physiological phenomenon in directing animal behaviors.

  18. Fires: what plant locations should we really protect

    International Nuclear Information System (INIS)

    Berry, D.L.

    1980-01-01

    A fire protection analysis technique was developed from earlier work involving the protection of nuclear power plants against acts of sabotage. Characteristics unique to fire phenomena were used to modify the sabotage analysis methodology. These characteristics include the effects of fuel loads, ventilation rates, heat loss areas, barrier ratings, and plant locations. The new fire analysis technique was applied to an example nuclear power plant having 85 different plant areas. It was found that some safety and nonsafety areas were both highly vulnerable to fire spread and important to overall safety, while other areas were found to be of marginal importance to fire safety

  19. Quark potential of spontaneous strings

    International Nuclear Information System (INIS)

    German, G.; Kleinert, H.

    1989-01-01

    The authors present some recent developments in string models with an extrinsic curvature term in action. Particular emphasis is placed upon the static quark potential and on the thermal deconfinement properties of spontaneous strings

  20. Hematome Extra - Dural Rachidien Spontane

    Directory of Open Access Journals (Sweden)

    Cl. Gros

    1967-01-01

    Full Text Available Four personal cases of Spontaneous Spinal Epidurdl Hemerrhage are Reported. And 29 additional cases have been analysed by reviewing the literature. The clinical radiologcal and surgical aspects were discussed.

  1. Spontaneous intraorbital hematoma: case report

    Directory of Open Access Journals (Sweden)

    Vinodan Paramanathan

    2010-12-01

    Full Text Available Vinodan Paramanathan, Ardalan ZolnourianQueen's Hospital NHS Foundation Trust, Burton on Trent, Staffordshire DE13 0RB, UKAbstract: Spontaneous intraorbital hematoma is an uncommon clinical entity seen in ophthalmology practice. It is poorly represented in the literature. Current evidence attributes it to orbital trauma, neoplasm, vascular malformations, acute sinusitis, and systemic abnormalities. A 65-year-old female presented with spontaneous intraorbital hematoma manifesting as severe ocular pains, eyelid edema, proptosis, and diplopia, without a history of trauma. Computer tomography demonstrated a fairly well defined extraconal lesion with opacification of the paranasal sinuses. The principal differential based on all findings was that of a spreading sinus infection and an extraconal tumor. An unprecedented finding of a spontaneous orbital hematoma was discovered when the patient was taken to theater. We discuss the rarity of this condition and its management.Keywords: hemorrhage, ophthalmology, spontaneous, intra-orbital, hematoma

  2. Spontaneity and international marketing performance

    OpenAIRE

    Souchon, Anne L.; Hughes, Paul; Farrell, Andrew M.; Nemkova, Ekaterina; Oliveira, Joao S.

    2016-01-01

    The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link. Purpose – The purpose of this paper is to ascertain how today’s international marketers can perform better on the global scene by harnessing spontaneity. Design/methodology/approach – The authors draw on contingency theory to develop a model of the spontaneity – international marketing performance relationship, and identify three potential m...

  3. Spontaneous ischaemic stroke in dogs

    DEFF Research Database (Denmark)

    Gredal, Hanne Birgit; Skerritt, G. C.; Gideon, P.

    2013-01-01

    Translation of experimental stroke research into the clinical setting is often unsuccessful. Novel approaches are therefore desirable. As humans, pet dogs suffer from spontaneous ischaemic stroke and may hence offer new ways of studying genuine stroke injury mechanisms.......Translation of experimental stroke research into the clinical setting is often unsuccessful. Novel approaches are therefore desirable. As humans, pet dogs suffer from spontaneous ischaemic stroke and may hence offer new ways of studying genuine stroke injury mechanisms....

  4. Spontaneous calf haematoma: case report.

    Science.gov (United States)

    Zubaidah, N H; Liew, N C

    2014-02-01

    Spontaneous calf haematoma is a rare condition and few case reports have been published in the English literature. Common conditions like deep vein thrombosis and traumatic gastrocnemius muscle tear need to be considered when a patient presents with unilateral calf swelling and tenderness. Ultrasound and Magnetic Resonance Imaging are essential for confirmation of diagnosis. The purpose of this paper is to report on a rare case of spontaneous calf hematoma and its diagnosis and management.

  5. Spontaneous droplet trampolining on rigid superhydrophobic surfaces

    Science.gov (United States)

    Schutzius, Thomas M.; Jung, Stefan; Maitra, Tanmoy; Graeber, Gustav; Köhme, Moritz; Poulikakos, Dimos

    2015-11-01

    Spontaneous removal of condensed matter from surfaces is exploited in nature and in a broad range of technologies to achieve self-cleaning, anti-icing and condensation control. But despite much progress, our understanding of the phenomena leading to such behaviour remains incomplete, which makes it challenging to rationally design surfaces that benefit from its manifestation. Here we show that water droplets resting on superhydrophobic textured surfaces in a low-pressure environment can self-remove through sudden spontaneous levitation and subsequent trampoline-like bouncing behaviour, in which sequential collisions with the surface accelerate the droplets. These collisions have restitution coefficients (ratios of relative speeds after and before collision) greater than unity despite complete rigidity of the surface, and thus seemingly violate the second law of thermodynamics. However, these restitution coefficients result from an overpressure beneath the droplet produced by fast droplet vaporization while substrate adhesion and surface texture restrict vapour flow. We also show that the high vaporization rates experienced by the droplets and the associated cooling can result in freezing from a supercooled state that triggers a sudden increase in vaporization, which in turn boosts the levitation process. This effect can spontaneously remove surface icing by lifting away icy drops the moment they freeze. Although these observations are relevant only to systems in a low-pressure environment, they show how surface texturing can produce droplet-surface interactions that prohibit liquid and freezing water-droplet retention on surfaces.

  6. Spontaneous unscheduled DNA synthesis in human lymphocytes

    International Nuclear Information System (INIS)

    Forell, B.; Myers, L.S. Jr.; Norman, A.

    1979-01-01

    The rate of spontaneous unscheduled DNA synthesis in human lymphocytes was estimated from measurements of tritiated thymidine incorporation into double-stranded DNA (ds-DNA) during incubation of cells in vitro. The contribution of scheduled DNA synthesis to the observed incorporation was reduced by inhibiting replication with hydroxyurea and by separating freshly replicated single-stranded DNA (ss-DNA) from repaired ds-DNA by column chromatography. The residual contribution of scheduled DNA synthesis was estimated by observing effects on thymidine incorporation of: (a) increasing the rate of production of apurinic sites, and alternatively, (b) increasing the number of cells in S-phase. Corrections based on estimates of endogenous pool size were also made. The rate of spontaneous unscheduled DNA synthesis is estimated to be 490 +- 120 thymidine molecules incorporated per cell per hour. These results compare favorably with estimates made from rates of depurination and depyrimidination of DNA, measured in molecular systems if we assume thymidine is incorporated by a short patch mechanism which incorporates an average of four bases per lesion

  7. Sensitivity to spatial and temporal scale and fire regime inputs in deriving fire regime condition class

    Science.gov (United States)

    Linda Tedrow; Wendel J. Hann

    2015-01-01

    The Fire Regime Condition Class (FRCC) is a composite departure measure that compares current vegetation structure and fire regime to historical reference conditions. FRCC is computed as the average of: 1) Vegetation departure (VDEP) and 2) Regime (frequency and severity) departure (RDEP). In addition to the FRCC rating, the Vegetation Condition Class (VCC) and Regime...

  8. Wildland fire in ecosystems: effects of fire on flora

    Science.gov (United States)

    James K. Brown; Jane Kapler Smith

    2000-01-01

    VOLUME 2: This state-of-knowledge review about the effects of fire on flora and fuels can assist land managers with ecosystem and fire management planning and in their efforts to inform others about the ecological role of fire. Chapter topics include fire regime classification, autecological effects of fire, fire regime characteristics and postfire plant community...

  9. A review of fire interactions and mass fires

    Science.gov (United States)

    Mark A. Finney; Sara S. McAllister

    2011-01-01

    The character of a wildland fire can change dramatically in the presence of another nearby fire. Understanding and predicting the changes in behavior due to fire-fire interactions cannot only be life-saving to those on the ground, but also be used to better control a prescribed fire to meet objectives. In discontinuous fuel types, such interactions may elicit fire...

  10. Use of Distributed Temperature Sensing Technology to Characterize Fire Behavior

    Directory of Open Access Journals (Sweden)

    Douglas Cram

    2016-10-01

    Full Text Available We evaluated the potential of a fiber optic cable connected to distributed temperature sensing (DTS technology to withstand wildland fire conditions and quantify fire behavior parameters. We used a custom-made ‘fire cable’ consisting of three optical fibers coated with three different materials—acrylate, copper and polyimide. The 150-m cable was deployed in grasslands and burned in three prescribed fires. The DTS system recorded fire cable output every three seconds and integrated temperatures every 50.6 cm. Results indicated the fire cable was physically capable of withstanding repeated rugged use. Fiber coating materials withstood temperatures up to 422 °C. Changes in fiber attenuation following fire were near zero (−0.81 to 0.12 dB/km indicating essentially no change in light gain or loss as a function of distance or fire intensity over the length of the fire cable. Results indicated fire cable and DTS technology have potential to quantify fire environment parameters such as heat duration and rate of spread but additional experimentation and analysis are required to determine efficacy and response times. This study adds understanding of DTS and fire cable technology as a potential new method for characterizing fire behavior parameters at greater temporal and spatial scales.

  11. Direct estimation of diffuse gaseous emissions from coal fires: current methods and future directions

    Science.gov (United States)

    Engle, Mark A.; Olea, Ricardo A.; O'Keefe, Jennifer M. K.; Hower, James C.; Geboy, Nicholas J.

    2013-01-01

    Coal fires occur in nature spontaneously, contribute to increases in greenhouse gases, and emit atmospheric toxicants. Increasing interest in quantifying coal fire emissions has resulted in the adaptation and development of specialized approaches and adoption of numerical modeling techniques. Overview of these methods for direct estimation of diffuse gas emissions from coal fires is presented in this paper. Here we take advantage of stochastic Gaussian simulation to interpolate CO2 fluxes measured using a dynamic closed chamber at the Ruth Mullins coal fire in Perry County, Kentucky. This approach allows for preparing a map of diffuse gas emissions, one of the two primary ways that gases emanate from coal fires, and establishing the reliability of the study both locally and for the entire fire. Future research directions include continuous and automated sampling to improve quantification of gaseous coal fire emissions.

  12. Radon exhalation in some building construction materials and effect of plastering and paints on the radon exhalation rate using fired bricks

    International Nuclear Information System (INIS)

    Sharma, Anil; Mahur, A.K.; Rajendra Prasad; Sonkawade, R.G.; Sharma, A.C.

    2013-01-01

    The technological endeavors of human beings have modified the levels of radiation exposure slightly. The emanation of radon is primarily associated with radium and its ultimate precursor uranium. The radiation dose received by human beings from indoor radon and its progeny is the largest of all doses received either by natural or man-made sources. In order to investigate the effect of paints available in the market on the radon exhalation rate from building materials, several bricks were collected. These bricks were plastered with a mixture of cement and sand. Before measurements bricks were dried for 24 hours. These plastered bricks were then coated with white wash and again dried for 1- 2 hours. After drying the bricks were coated with different brands and colors of paints. Radon exhalation rates measurements were carried out for these painted bricks using 'Sealed can Technique' cylindrical plastic 'Can' of 7.5 cm height and 7.0 cm diameter was sealed to the individual samples by plastic can. In each 'Can' a LR-115 type II plastic detector (2 cm 2cm) was fixed at the top inside of the 'Can', such that the sensitive surface of the detector faces the material and is freely exposed to the emergent radon. Radon decays in the volume of the can record the alpha particles resulting from the 218 Po and 214 Po deposited on the inner wall of the 'Can'. Radon and its daughters will reach an equilibrium in concentration after one week or more. Hence the equilibrium activity of the emergent radon can be obtained from the geometry of the can and the time of exposure. The results will be discussed. (author)

  13. Spontaneous breathing during lung-protective ventilation in an experimental acute lung injury model: high transpulmonary pressure associated with strong spontaneous breathing effort may worsen lung injury.

    Science.gov (United States)

    Yoshida, Takeshi; Uchiyama, Akinori; Matsuura, Nariaki; Mashimo, Takashi; Fujino, Yuji

    2012-05-01

    We investigated whether potentially injurious transpulmonary pressure could be generated by strong spontaneous breathing and exacerbate lung injury even when plateau pressure is limited to ventilation, each combined with weak or strong spontaneous breathing effort. Inspiratory pressure for low tidal volume ventilation was set at 10 cm H2O and tidal volume at 6 mL/kg. For moderate tidal volume ventilation, the values were 20 cm H2O and 7-9 mL/kg. The groups were: low tidal volume ventilation+spontaneous breathingweak, low tidal volume ventilation+spontaneous breathingstrong, moderate tidal volume ventilation+spontaneous breathingweak, and moderate tidal volume ventilation+spontaneous breathingstrong. Each group had the same settings for positive end-expiratory pressure of 8 cm H2O. Respiratory variables were measured every 60 mins. Distribution of lung aeration and alveolar collapse were histologically evaluated. Low tidal volume ventilation+spontaneous breathingstrong showed the most favorable oxygenation and compliance of respiratory system, and the best lung aeration. By contrast, in moderate tidal volume ventilation+spontaneous breathingstrong, the greatest atelectasis with numerous neutrophils was observed. While we applied settings to maintain plateau pressure at ventilation+spontaneous breathingstrong, transpulmonary pressure rose >33 cm H2O. Both minute ventilation and respiratory rate were higher in the strong spontaneous breathing groups. Even when plateau pressure is limited to mechanical ventilation, transpulmonary pressure and tidal volume should be strictly controlled to prevent further lung injury.

  14. Fires and Food Safety

    Science.gov (United States)

    ... Forms FSIS United States Department of Agriculture Food Safety and Inspection Service About FSIS District Offices Careers ... JSR 286) Actions ${title} Loading... Fires and Food Safety Fire! Few words can strike such terror. Residential ...

  15. Filosofiens historiografi: Fire genrer

    DEFF Research Database (Denmark)

    Rorty, Richard

    2007-01-01

    Oversættelse af Richard Rortys artikel "Filosofiens historiografi: Fire genrer" Udgivelsesdato: 26 Oktober......Oversættelse af Richard Rortys artikel "Filosofiens historiografi: Fire genrer" Udgivelsesdato: 26 Oktober...

  16. Tunnel fire dynamics

    CERN Document Server

    Ingason, Haukur; Lönnermark, Anders

    2015-01-01

    This book covers a wide range of issues in fire safety engineering in tunnels, describes the phenomena related to tunnel fire dynamics, presents state-of-the-art research, and gives detailed solutions to these major issues. Examples for calculations are provided. The aim is to significantly improve the understanding of fire safety engineering in tunnels. Chapters on fuel and ventilation control, combustion products, gas temperatures, heat fluxes, smoke stratification, visibility, tenability, design fire curves, heat release, fire suppression and detection, CFD modeling, and scaling techniques all equip readers to create their own fire safety plans for tunnels. This book should be purchased by any engineer or public official with responsibility for tunnels. It would also be of interest to many fire protection engineers as an application of evolving technical principles of fire safety.

  17. Fire Stations - 2007

    Data.gov (United States)

    Kansas Data Access and Support Center — Fire Station Locations in Kansas Any location where fire fighters are stationed at or based out of, or where equipment that such personnel use in carrying out their...

  18. Seerley Road Fire Site

    Science.gov (United States)

    A barn caught fire at on Seerley Road, Indianapolis. Five storage drums believed to contain metallic potassium were involved in the fire. EPA will perform additional sampling as part of removal operations and safe offsite transportation.

  19. Buildings exposed to fire

    International Nuclear Information System (INIS)

    1987-01-01

    The 24 lectures presented to the colloquium cover the following subject fields: (1) Behaviour of structural components exposed to fire; (2) Behaviour of building materials exposed to fire; (3) Thermal processes; (4) Safety related, theoretical studies. (PW) [de

  20. Interagency Wildland Fire Cooperation

    National Research Council Canada - National Science Library

    2004-01-01

    Wildlife Fire Assistance includes training personnel, forms partnerships for prescribed burns, state and regional data for fire management plans, develops agreements for DoD civilians to be reimbursed...

  1. Spacecraft Fire Safety Demonstration

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of the Spacecraft Fire Safety Demonstration project is to develop and conduct large-scale fire safety experiments on an International Space Station...

  2. Fire Stations - 2009

    Data.gov (United States)

    Kansas Data Access and Support Center — Fire Stations in Kansas Any location where fire fighters are stationed or based out of, or where equipment that such personnel use in carrying out their jobs is...

  3. The OECD FIRE database

    International Nuclear Information System (INIS)

    Angner, A.; Berg, H.P.; Roewekamp, M.; Werner, W.; Gauvain, J.

    2007-01-01

    Realistic modelling of fire scenarios is still difficult due to the scarcity of reliable data needed for deterministic and probabilistic fire safety analysis. Therefore, it has been recognized as highly important to establish a fire event database on an international level. In consequence, several member countries of the Nuclear Energy Agency of the OECD have decided in 2000 to establish the International Fire Data Exchange Project (OECD FIRE) to encourage multilateral co-operation in the collection and analysis of data related to fire events at nuclear power plants. This paper presents the OECD FIRE project objectives, work scope and current status of the OECD FIRE database after 3 years of operation as well as first preliminary statistical insights gained from the collected data. (orig.)

  4. FIRE CHARACTERISTICS FOR ADVANCED MODELLING OF FIRES

    Directory of Open Access Journals (Sweden)

    Otto Dvořák

    2016-07-01

    Full Text Available This paper summarizes the material and fire properties of solid flammable/combustible materials /substances /products, which are used as inputs for the computer numerical fire models. At the same time it gives the test standards for their determination.

  5. Loft fire protection

    International Nuclear Information System (INIS)

    White, E.R.; Jensen, J.D.

    1980-01-01

    Quantified criteria that was developed and applied to provide in-depth fire protection for the Loss of Fluid Test (LOFT) Facility are presented. The presentation describes the evolution process that elevated the facility's fire protection from minimal to that required for a highly protected risk or improved risk. Explored are some infrequently used fire protection measures that are poorly understood outside the fire protection profession

  6. A case of spontaneous ventriculocisternostomy

    International Nuclear Information System (INIS)

    Yamane, Kanji; Yoshimoto, Hisanori; Harada, Kiyoshi; Uozumi, Tohru; Kuwabara, Satoshi.

    1983-01-01

    The authors experienced a case of spontaneous ventriculocisternostomy diagnosed by CT scan with metrizamide and Conray. Patient was 23-year-old male who had been in good health until one month before admission, when he began to have headache and tinnitus. He noticed bilateral visual acuity was decreased about one week before admission and vomiting appeared two days before admission. He was admitted to our hospital because of bilateral papilledema and remarkable hydrocephalus diagnosed by CT scan. On admission, no abnormal neurological signs except for bilateral papilledema were noted. Immediately, right ventricular drainage was performed. Pressure of the ventricle was over 300mmH 2 O and CSF was clear. PVG and PEG disclosed an another cavity behind the third ventricle, which was communicated with the third ventricle, and occlusion of aqueduct of Sylvius. Metrizamide CT scan and Conray CT scan showed a communication between this cavity and quadrigeminal and supracerebellar cisterns. On these neuroradiological findings, the diagnosis of obstructive hydrocephalus due to benign aqueduct stenosis accompanied with spontaneous ventriculocisternostomy was obtained. Spontaneous ventriculocisternostomy was noticed to produce arrest of hydrocephalus, but with our case, spontaneous regression of such symptoms did not appeared. By surgical ventriculocisternostomy (method by Torkildsen, Dandy, or Scarff), arrest of hydrocephalus was seen in about 50 to 70 per cent, which was the same results as those of spontaneous ventriculocisternostomy. It is concluded that VP shunt or VA shunt is thought to be better treatment of obstructive hydrocephalus than the various kinds of surgical ventriculocisternostomy. (J.P.N.)

  7. Fire analyses in central and disposal tunnels by APROS; Keskus- ja loppusijoitustunneleiden palotarkasteluja APROSilla

    Energy Technology Data Exchange (ETDEWEB)

    Peltokorpi, L.; Kukkola, T.; Nieminen, J. [Fortum Power and Heat Oy, Espoo (Finland)

    2012-12-15

    The central tunnels and the disposal tunnels on the north-east disposal area are the target areas of the fire studies. Target is to maintain under pressure in the fire zone in case of a fire. In the central tunnels a fire of a drilling jumbo with moderate fire propagation is used as heat release rate. In the disposal tunnel the heat release rate of a canister transfer and installation vehicle fire received as a result of the pyrolysis analyze as well as an average heat release rate of a van fire are used. Inlet air is to be conducted to the back end of the fire zone and the exhaust is to be lead out from the beginning of the fire zone. The worst location of the fire is in the beginning of the fire zone just below of the exhaust air clap valve. The size of the fire zone does not have big impact on pressure. In all analyzed cases the fire zone remains too long time over pressurized. Inlet air flow of a 30 m{sup 3}/s is too much. The rotation controlled booster blowers will solve the pressure problems of the fire zone in fire cases. The rotation is controlled by the fire zone pressure. The fire of the canister transfer and installation vehicle in the central tunnel will not cause problems. The disposal tunnel fire door should be kept open, if the canister transfer and installation vehicle or the bentonite blocks transfer and installation vehicle is driven into the disposal tunnel. If a fire is caught in the disposal tunnel then the fire zone in the central tunnel is to be closed and the pressure is controlled by the rotation controlled booster blowers. If a personnel car or a van is driven into the disposal tunnel, then fire door of the disposal is to be kept closed against fires in the central tunnel. (orig.)

  8. Mine shaft fire and smoke protection systems - an update on hardware development and in-mine testing

    International Nuclear Information System (INIS)

    Johnson, G.A.

    1982-01-01

    In 1976, The Bureau of Mines developed a prototype system to sense and extinguish fires in shafts and shaft stations in underground metal and nonmetal mines. Subsequent work modified this technology to include fueling areas, spontaneous combustion zones and coal mines. This paper updates IC-8783 ''In-mine Fire Tests of Mine Shaft Fire and Smoke Protection Systems'', which was published in 1978 and summarized the design and in-mine, actual fire testing of the first prototype mine shaft fire and smoke protection system. This paper also updates related work from IC-8775 ''Spontaneous Oxidation and Combustion of Sulfide Ores in Underground Mines, (also published in 1978) and IC-8808 ''In-mine Evaluation of Underground Fire and Smoke Detectors'', (published in early 1979)

  9. Fire as Technology

    Science.gov (United States)

    Rudolph, Robert N.

    2011-01-01

    In this article, the author describes a project that deals with fire production as an aspect of technology. The project challenges students to be survivors in a five-day classroom activity. Students research various materials and methods to produce fire without the use of matches or other modern combustion devices, then must create "fire" to keep…

  10. Fourmile Canyon Fire Findings

    Science.gov (United States)

    Russell Graham; Mark Finney; Chuck McHugh; Jack Cohen; Dave Calkin; Rick Stratton; Larry Bradshaw; Ned Nikolov

    2012-01-01

    The Fourmile Canyon Fire burned in the fall of 2010 in the Rocky Mountain Front Range adjacent to Boulder, Colorado. The fire occurred in steep, rugged terrain, primarily on privately owned mixed ponderosa pine and Douglas-fir forests. The fire started on September 6 when the humidity of the air was very dry (¡Ö

  11. Autonomous Forest Fire Detection

    NARCIS (Netherlands)

    Breejen, E. den; Breuers, M.; Cremer, F.; Kemp, R.A.W.; Roos, M.; Schutte, K.; Vries, J.S. de

    1998-01-01

    Forest fire detection is a very important issue in the pre-suppression process. Timely detection allows the suppression units to reach the fire in its initial stages and this will reduce the suppression costs considerably. The autonomous forest fire detection principle is based on temporal contrast

  12. Fundamentals of Fire Phenomena

    DEFF Research Database (Denmark)

    Quintiere, James

    analyses. Fire phenomena encompass everything about the scientific principles behind fire behaviour. Combining the principles of chemistry, physics, heat and mass transfer, and fluid dynamics necessary to understand the fundamentals of fire phenomena, this book integrates the subject into a clear...

  13. Fire Department Emergency Response

    International Nuclear Information System (INIS)

    Blanchard, A.; Bell, K.; Kelly, J.; Hudson, J.

    1997-09-01

    In 1995 the SRS Fire Department published the initial Operations Basis Document (OBD). This document was one of the first of its kind in the DOE complex and was widely distributed and reviewed. This plan described a multi-mission Fire Department which provided fire, emergency medical, hazardous material spill, and technical rescue services

  14. Equipping tomorrow's fire manager

    Science.gov (United States)

    Christopher A. Dicus

    2008-01-01

    Fire managers are challenged with an ever-increasing array of both responsibilities and critics. As in the past, fire managers must master the elements of fire behavior and ecology using the latest technologies. In addition, today’s managers must be equipped with the skills necessary to understand and liaise with a burgeoning group of vocal stakeholders while also...

  15. Fire and forest meteorology

    Science.gov (United States)

    SA Ferguson; T.J. Brown; M. Flannigan

    2005-01-01

    The American Meteorological Society symposia series on Fire and Forest Meteorology provides biennial forums for atmospheric and fire scientists to introduce and discuss the latest and most relevant research on weather, climate and fire. This special issue highlights significant work that was presented at the Fifth Symposium in Orlando, Florida during 16-20 November...

  16. Cost of two fire

    International Nuclear Information System (INIS)

    Vasil'ev, Yu.

    2001-01-01

    The problem of the protection of nuclear sites in connection with the fires in summer of 2000 near two greatest nuclear sites: the Pacific Northwest National Laboratory located on the site of Hanford Nuclear Center, and Los Alamos National Laboratory is considered. Both fires occur beyond the Laboratories. Undertaken urgent procedures for fire fighting and recovery of the objects are characterized [ru

  17. Sync the emerging science of spontaneous order

    CERN Document Server

    Strogatz, Steven

    2003-01-01

    At the heart of the universe is a steady, insistent beat, the sound of cycles in sync. Along the tidal rivers of Malaysia, thousands of fireflies congregate and flash in unison; the moon spins in perfect resonance with its orbit around the earth; our hearts depend on the synchronous firing of ten thousand pacemaker cells. While the forces that synchronize the flashing of fireflies may seem to have nothing to do with our heart cells, there is in fact a deep connection. Synchrony is a science in its infancy, and Strogatz is a pioneer in this new frontier in which mathematicians and physicists attempt to pinpoint just how spontaneous order emerges from chaos. From underground caves in Texas where a French scientist spent six months alone tracking his sleep-wake cycle, to the home of a Dutch physicist who in 1665 discovered two of his pendulum clocks swinging in perfect time, this fascinating book spans disciplines, continents, and centuries. Engagingly written for readers of books such as Chaos and The Elegant ...

  18. Sodium Fire Demonstration Facility Design and Operation

    International Nuclear Information System (INIS)

    Cho, Youngil; Kim, Jong-Man; Lee, Jewhan; Hong, Jonggan; Yeom, Sujin; Cho, Chungho; Jung, Min-Hwan; Gam, Da-Young; Jeong, Ji-Young

    2014-01-01

    Although sodium has good characteristics such as high heat transfer rate and stable nuclear property, it is difficult to manage because of high reactivity. Sodium is solid at the room temperature and it easily reacts with oxygen resulting in fire due to the reaction heat. Thus, sodium must be stored in a chemically stable place, i.e., an inert gas-sealed or oil filled vessel. When a sodium fire occurs, the Na 2 O of white fume is formed. It is mainly composed of Na 2 O 2 , NaOH, and Na 2 CO 3 , ranging from 0.1 to several tens of micrometers in size. It is known that the particle size increases by aggregation during floating in air. Thus, the protection method is important and should be considered in the design and operation of a sodium system. In this paper, sodium fire characteristics are described, and the demonstration utility of outbreak of sodium fire and its extinguishing is introduced. In this paper, sodium fire characteristics and a demonstration facility are described. The introduced sodium fire demonstration facility is the only training device used to observe a sodium fire and extinguish it domestically. Furthermore, the type of sodium fire will be diversified with the enhancement of the utility. It is expected that this utility will contribute to experience in the safe treatment of sodium by the handlers

  19. Body Mass Index and spontaneous miscarriage.

    LENUS (Irish Health Repository)

    Turner, Michael J

    2012-02-01

    OBJECTIVE: We compared the incidence of spontaneous miscarriage in women categorised as obese, based on a Body Mass Index (BMI) >29.9 kg\\/m(2), with women in other BMI categories. STUDY DESIGN: In a prospective observational study conducted in a university teaching hospital, women were enrolled at their convenience in the first trimester after a sonogram confirmed an ongoing singleton pregnancy with fetal heart activity present. Maternal height and weight were measured digitally and BMI calculated. Maternal body composition was measured by advanced bioelectrical impedance analysis. RESULTS: In 1200 women, the overall miscarriage rate was 2.8% (n=33). The mean gestational age at enrolment was 9.9 weeks. In the obese category (n=217), the miscarriage rate was 2.3% compared with 3.3% in the overweight category (n=329), and 2.3% in the normal BMI group (n=621). There was no difference in the mean body composition parameters, particularly fat mass parameters, between those women who miscarried and those who did not. CONCLUSIONS: In women with sonographic evidence of fetal heart activity in the first trimester, the rate of spontaneous miscarriage is low and is not increased in women with BMI>29.9 kg\\/m(2) compared to women in the normal BMI category.

  20. Progesterone to prevent spontaneous preterm birth

    Science.gov (United States)

    Romero, Roberto; Yeo, Lami; Chaemsaithong, Piya; Chaiworapongsa, Tinnakorn; Hassan, Sonia

    2014-01-01

    Summary Preterm birth is the leading cause of perinatal morbidity and mortality worldwide, and its prevention is an important healthcare priority. Preterm parturition is one of the ‘great obstetrical syndromes’ and is caused by multiple etiologies. One of the mechanisms of disease is the untimely decline in progesterone action, which can be manifested by a sonographic short cervix in the midtrimester. The detection of a short cervix in the midtrimester is a powerful risk factor for preterm delivery. Vaginal progesterone can reduce the rate of preterm delivery by 45%, and the rate of neonatal morbidity (admission to neonatal intensive care unit, respiratory distress syndrome, need for mechanical ventilation, etc.). To prevent one case of spontaneous preterm birth birth in women with a short cervix both with and without a prior history of preterm birth. In patients with a prior history of preterm birth, vaginal progesterone is as effective as cervical cerclage to prevent preterm delivery. 17α-Hydroxyprogesterone caproate has not been shown to be effective in reducing the rate of spontaneous preterm birth in women with a short cervix. PMID:24315687

  1. Spontaneous fungal peritonitis: Epidemiology, current evidence and future prospective.

    Science.gov (United States)

    Fiore, Marco; Leone, Sebastiano

    2016-09-14

    Spontaneous bacterial peritonitis is a complication of ascitic patients with end-stage liver disease (ESLD); spontaneous fungal peritonitis (SFP) is a complication of ESLD less known and described. ESLD is associated to immunodepression and the resulting increased susceptibility to infections. Recent perspectives of the management of the critically ill patient with ESLD do not specify the rate of isolation of fungi in critically ill patients, not even the antifungals used for the prophylaxis, neither optimal treatment. We reviewed, in order to focus the epidemiology, characteristics, and, considering the high mortality rate of SFP, the use of optimal empirical antifungal therapy the current literature.

  2. Spontaneous emission of quantum dots in disordered photonic crystal waveguides

    DEFF Research Database (Denmark)

    Sapienza, Luca; Nielsen, Henri Thyrrestrup; Stobbe, Søren

    2010-01-01

    We report on the enhancement of the spontaneous emission rate of single semiconductor quantum dots embedded in a photonic crystal waveguide with engineered disorder. Random high-Q cavities, that are signature of Anderson localization, are measured in photoluminescence experiments and appear...... in the slow light regime of the waveguide mode. Time resolved experiments show a 15-fold enhancement of the spontaneous emission rate, with coupling efficiencies of single photons into Anderson localized cavity modes of 94%. These results show that the performances of Anderson-localized cavities...

  3. Neural network regulation driven by autonomous neural firings

    Science.gov (United States)

    Cho, Myoung Won

    2016-07-01

    Biological neurons naturally fire spontaneously due to the existence of a noisy current. Such autonomous firings may provide a driving force for network formation because synaptic connections can be modified due to neural firings. Here, we study the effect of autonomous firings on network formation. For the temporally asymmetric Hebbian learning, bidirectional connections lose their balance easily and become unidirectional ones. Defining the difference between reciprocal connections as new variables, we could express the learning dynamics as if Ising model spins interact with each other in magnetism. We present a theoretical method to estimate the interaction between the new variables in a neural system. We apply the method to some network systems and find some tendencies of autonomous neural network regulation.

  4. Spontaneous rupture of vaginal enterocele

    DEFF Research Database (Denmark)

    Svendsen, J H; Galatius, H; Hansen, P K

    1985-01-01

    Spontaneous rupture of an enterocele is a rare complication. Only 24 cases including the present case have been reported in the literature. The patients were elderly and had had at least one vaginal operation. The patients were remarkably unaffected symptomatically on admission.......Spontaneous rupture of an enterocele is a rare complication. Only 24 cases including the present case have been reported in the literature. The patients were elderly and had had at least one vaginal operation. The patients were remarkably unaffected symptomatically on admission....

  5. Spontaneous baryogenesis from asymmetric inflaton

    International Nuclear Information System (INIS)

    Takahashi, Fuminobu

    2015-10-01

    We propose a variant scenario of spontaneous baryogenesis from asymmetric inflaton based on current-current interactions between the inflaton and matter fields with a non-zero B-L charge. When the inflaton starts to oscillate around the minimum after inflation, it may lead to excitation of a CP-odd component, which induces an effective chemical potential for the B-L number through the current-current interactions. We study concrete inflation models and show that the spontaneous baryogenesis scenario can be naturally implemented in the chaotic inflation in supergravity.

  6. Fires of sodium installations

    International Nuclear Information System (INIS)

    Hajek, L.; Tlalka, R.

    1984-01-01

    A survey is presented of the literature dealing with fires of sodium installations between 1974 and 1981. Also described are three experimental fires of ca 50 kg of sodium in an open area, monitored by UJV Rez. The experimental conditions of the experiments are described and a phenomenological description is presented of the course of the fires. The experiments showed a relationship between wind velocity in the area surrounding the fire and surface temperature of the sodium flame. Systems analysis methods were applied to sodium area, spray and tube fires. (author)

  7. Fire Protection Program Manual

    Energy Technology Data Exchange (ETDEWEB)

    Sharry, J A

    2012-05-18

    This manual documents the Lawrence Livermore National Laboratory (LLNL) Fire Protection Program. Department of Energy (DOE) Orders 420.1B, Facility Safety, requires LLNL to have a comprehensive and effective fire protection program that protects LLNL personnel and property, the public and the environment. The manual provides LLNL and its facilities with general information and guidance for meeting DOE 420.1B requirements. The recommended readers for this manual are: fire protection officers, fire protection engineers, fire fighters, facility managers, directorage assurance managers, facility coordinators, and ES and H team members.

  8. Nuclear Power Plant Fire Protection Research Program

    International Nuclear Information System (INIS)

    Datta, A.

    1985-07-01

    The goal is to develop test data and analytical capabilities to support the evaluation of: (1) the contribution of fires to the risk from nuclear power plants; (2) the effects of fires on control room equipment and operations; and (3) the effects of actuation of fire suppression systems on safety equipment. A range of fire sources will be characterized with respect to their energy and mass evolution, including smoke, corrosion products, and electrically conductive products of combustion. An analytical method for determining the environment resulting from fire will be developed. This method will account for the source characteristics, the suppression action following detection of the fire, and certain parameters specific to the plant enclosure in which the fire originates, such as the geometry of the enclosure and the ventilation rate. The developing local environment in the vicinity of safety-related equipment will be expressed in terms of temperatures, temperature rise rates, heat fluxes, and moisture and certain species content. The response of certain safe shutdown equipment and components to the environmental conditions will be studied. The objective will be to determine the limits of environmental conditions that a component may be exposed to without impairment of its ability to function

  9. Coupled atmosphere-wildland fire modelling

    Directory of Open Access Journals (Sweden)

    Jacques Henri Balbi

    2009-10-01

    Full Text Available Simulating the interaction between fire and atmosphere is critical to the estimation of the rate of spread of the fire. Wildfire’s convection (i.e., entire plume can modify the local meteorology throughout the atmospheric boundary layer and consequently affect the fire propagation speed and behaviour. In this study, we use for the first time the Méso-NH meso-scale numerical model coupled to the point functional ForeFire simplified physical front-tracking wildfire model to investigate the differences introduced by the atmospheric feedback in propagation speed and behaviour. Both numerical models have been developed as research tools for operational models and are currently used to forecast localized extreme events. These models have been selected because they can be run coupled and support decisions in wildfire management in France and Europe. The main originalities of this combination reside in the fact that Méso-NH is run in a Large Eddy Simulation (LES configuration and that the rate of spread model used in ForeFire provides a physical formulation to take into account the effect of wind and slope. Simulations of typical experimental configurations show that the numerical atmospheric model is able to reproduce plausible convective effects of the heat produced by the fire. Numerical results are comparable to estimated values for fire-induced winds and present behaviour similar to other existing numerical approaches.

  10. Patchwork-Type Spontaneous Activity in Neonatal Barrel Cortex Layer 4 Transmitted via Thalamocortical Projections

    Directory of Open Access Journals (Sweden)

    Hidenobu Mizuno

    2018-01-01

    Full Text Available Summary: Establishment of precise neuronal connectivity in the neocortex relies on activity-dependent circuit reorganization during postnatal development; however, the nature of cortical activity during this period remains largely unknown. Using two-photon calcium imaging of the barrel cortex in vivo during the first postnatal week, we reveal that layer 4 (L4 neurons within the same barrel fire synchronously in the absence of peripheral stimulation, creating a “patchwork” pattern of spontaneous activity corresponding to the barrel map. By generating transgenic mice expressing GCaMP6s in thalamocortical axons, we show that thalamocortical axons also demonstrate the spontaneous patchwork activity pattern. Patchwork activity is diminished by peripheral anesthesia but is mostly independent of self-generated whisker movements. The patchwork activity pattern largely disappeared during postnatal week 2, as even L4 neurons within the same barrel tended to fire asynchronously. This spontaneous L4 activity pattern has features suitable for thalamocortical (TC circuit refinement in the neonatal barrel cortex. : By two-photon calcium imaging of layer 4 neurons and thalamocortical axon terminals in neonatal mouse barrel cortex, Mizuno et al. find a patchwork-like spontaneous activity pattern corresponding to the barrel map, which may be important for thalamocortical circuit maturation. Keywords: activity-dependent development, spontaneous activity, synchronized activity, barrel cortex, thalamocortical axons, neonates, in vivo calcium imaging, awake, single-cell labeling, whisker monitoring

  11. Control Of Motor Unit Firing During Step-Like Increases In Voluntary Force

    Directory of Open Access Journals (Sweden)

    Xiaogang eHu

    2014-09-01

    Full Text Available In most skeletal muscles, force is generated by a combination of motor unit (MU recruitment and increases in the firing rate of previously active MUs. Two contrasting patterns of firing rate organization have been reported. In the first pattern, the earliest recruited MUs reach the highest firing rates as force is increased, and later recruited MUs fire at lower rates. When firing rate of multiple MUs are superimposed, these rate trajectories form a concentric layered profile termed ‘onion skin’. In the second pattern, called ‘reverse onion skin’, later recruited MUs reach higher firing rates, and crossing of firing rate trajectories for recorded MUs is common (although such trajectories are assembled routinely from different trials. Our present study examined the firing rate organization of concurrently active MUs of the first dorsal interosseous muscle during serial, step-like increases in isometric abduction forces. We used a surface sensor array coupled with MU discrimination algorithms to characterize MU firing patterns. Our objective was to determine whether ‘onion skin’ profiles are contingent upon the force trajectory of the motor task, examined here using step-like increases of force output, and also whether they are manifested at different force levels.Our results revealed that the overall ‘onion skin’ firing rate profile was retained as the force level increased with each force step up to 15% MVC. However, the distribution of firing rates across MUs was compressed with increasing force, and overlapping firing rate of units were observed. This rate compression was largely due to rate saturation of the relatively high frequency discharging MUs.Our results reflect flexible firing patterns across MUs at different levels of excitation drive. It is also evident that many units did not follow all the step increases consistently. This failure to track firing rate increases at higher forces could be due to an intrinsically

  12. Fire retardant formulations

    DEFF Research Database (Denmark)

    2017-01-01

    The present invention relates to compositions where a substrate is liable to catch fire such as bituminous products, paints, carpets or the like. The invention relates to a composition comprising 40-95 weight % of a substrate to be rendered fire resistant such as bituminous material or paint......, carpets which substrate is mixed with 5-60 weight % of a fire retardant component. The invention relates to a fire retardant component comprising or being constituted of attapulgite, and a salt being a source of a blowing or expanding agent, where the attapulgite and the salt are electrostatically...... connected by mixing and subjecting the mixture of the two components to agitation. Also, the invention relates to compositions comprising 40-95 weight % of a substrate to be rendered fire resistant mixed with 5-60 weight % of a fire retardant according to claim 1 or 2, which fire retardant component...

  13. Dayton Aircraft Cabin Fire Model, Version 3. Volume II. Program User’s Guide and Appendices.

    Science.gov (United States)

    1982-06-01

    HEAT RELEASE RATE (BTU/FT*FT*SEC) FOR A FIRE C FLML - FLAME LENGTH OF A FIRE. SUBSCR IS FIRE NUMBER (FT) C FSN1 - COUNTER OF NUMBER OF FLAMING...53H ENTRMNT FLAME LENGTH ABSN COEFF SMOKE GEN RATE 0 2 *14HXY CNSPTN RATE/ 3 9X,53H(SG FT) (CU FT/SEC) (BTU/SEC) (CU FT/SEC) 4 .53H (FT) (l/FT) (PART...THE CENTER OF THE FIRE BASE FROM THE C FLOOR C C YZ - THE HYDRAULIC RADIUS OF THE FIRE BASE AREA C C FLML - THE FLAME LENGTH FOR THE FIRE C C ALPC

  14. Post-fire vegetation dynamics in Portugal

    Science.gov (United States)

    Gouveia, C.; Dacamara, C. C.; Trigo, R. M.

    2009-04-01

    The number of fires and the extent of the burned surface in Mediterranean Europe have increased significantly during the last three decades. This may be due either to modifications in land-use (e.g. land abandonment and fuel accumulation) or to climatic changes (e.g. reduction of fuel humidity), both factors leading to an increase of fire risk and fire spread. As in the Mediterranean ecosystems, fires in Portugal have an intricate effect on vegetation regeneration due to the complexity of landscape structures as well as to the different responses of vegetation to the variety of fire regimes. A thorough evaluation of vegetation recovery after fire events becomes therefore crucial in land management. In the above mentioned context remote sensing plays an important role because of its ability to monitor and characterise post-fire vegetation dynamics. A number of fire recovery studies, based on remote sensing, have been conducted in regions characterised by Mediterranean climates and the use of NDVI to monitor plant regeneration after fire events was successfully tested (Díaz-Delgado et al., 1998). In particular, several studies have shown that rapid regeneration occurs within the first 2 years after the fire occurrences, with distinct recovery rates according to the geographical facing of the slopes (Pausas and Vallejo, 1999). In 2003 Portugal was hit by the most devastating sequence of large fires, responsible by a total burnt area of 450 000 ha (including 280 000 ha of forest), representing about 5% of the Portuguese mainland (Trigo et al., 2006). The aim of the present work is to assess and monitor the vegetation behaviour over Portugal following the 2003 fire episodes. For this purpose we have used the regional fields of the Normalized Difference Vegetation Index (NDVI) as obtained from the VEGETATION-SPOT5 instrument, from 1999 to 2008. We developed a methodology to identify large burnt scars in Portugal for the 2003 fire season. The vegetation dynamics was then

  15. Fire debris analysis for forensic fire investigation using laser induced breakdown spectroscopy (LIBS)

    Science.gov (United States)

    Choi, Soojin; Yoh, Jack J.

    2017-08-01

    The possibility verification of the first attempt to apply LIBS to arson investigation was performed. LIBS has capabilities for real time in-situ analysis and depth profiling. It can provide valuable information about the fire debris that are complementary to the classification of original sample components and combustion residues. In this study, fire debris was analyzed to determine the ignition source and existence of a fire accelerant using LIBS spectra and depth profiling analysis. Fire debris chemical composition and carbon layer thickness determines the possible ignition source while the carbon layer thickness of combusted samples represents the degree of sample carbonization. When a sample is combusted with fire accelerants, a thicker carbon layer is formed because the burning rate is increased. Therefore, depth profiling can confirm the existence of combustion accelerants, which is evidence of arson. Also investigation of fire debris by depth profiling is still possible when a fire is extinguished with water from fire hose. Such data analysis and in-situ detection of forensic signals via the LIBS may assist fire investigation at crime scenes.

  16. Investigation of Fire Safety Awareness and Management in Mall

    Directory of Open Access Journals (Sweden)

    Abdul Rahim N.

    2014-03-01

    Full Text Available In spite of having sufficient fire safety system installed in buildings, the incidence of fire hazard becomes the furthermost and supreme threat to health and safety, as well as property to any community. In order to make sure that the safety of the building and its users, the fundamental features depends on the fire precaution system and equipment which should be according to the standard requirements. Nevertheless, the awareness on fire safety could necessarily alleviate the damages or rate of fatality during the event of fire. This paper presents the results on the investigation of fire safety awareness and management, concentrating on shopping mall. The endeavour of this study is to explore the level of fire safety knowledge of the users in the mall, and to study the effectiveness level of fire safety management in a mall. From the study, public awareness is highly related to understanding human behaviour and their personal background. The respondents’ levels of awareness are rather low, which reflects on their poor action when facing emergency situation during fire. The most effective methods identified to improve the awareness and effectiveness of fire safety level is through involvement in related fire safety programmes, distribution of pamphlets or brochures on fire safety and appointing specific personnel for Emergency Response Team in the mall.

  17. Burns resulting from spontaneous combustion of electronic cigarettes: a case series.

    Science.gov (United States)

    Sheckter, Clifford; Chattopadhyay, Arhana; Paro, John; Karanas, Yvonne

    2016-01-01

    Electronic cigarette (e-cigarette) sales have grown rapidly in recent years, coinciding with a public perception that they are a safer alternative to traditional cigarettes. However, there have been numerous media reports of fires associated with e-cigarette spontaneous combustion. Three severe burns caused by spontaneous combustion of e-cigarettes within a 6-month period were treated at the Santa Clara Valley Medical Center Burn Unit. Patients sustained partial and full-thickness burns. Two required hospitalization and surgical treatment. E-cigarettes are dangerous devices and have the potential to cause significant burns. Consumers and the general public should be made aware of these life-threatening devices.

  18. The Spontaneous Combustion of Railway Ties and Asphalt Shingles

    Science.gov (United States)

    Leslie, Geoffrey

    Many Low Carbon Fuels (LCFs) present unknown spontaneous combustion risks, which must be quantified before their use as fossil fuel replacements. Wood and coal spontaneous combustion is well understood; however, LCFs weather, and subsequent chemical changes could affect their spontaneous combustion properties. LCF spontaneous combustion could lead to accidental fires with possible loss of life, limb and property. The spontaneous combustion risks of two LCFs, discarded creosote-treated wooden railway ties and roofing asphalt shingles, were investigated with calorimetry and heat transfer experiments. Chemical changes due to weathering were studied with pyrolysis-Gas Chromatography/Mass Spectrometry (py-GC/MS). Creosote-treated wooden railway tie dust, roofing asphalt shingle particles, poplar wood pellets, and petroleum coke self-heating were studied with isothermal calorimetry. Railway tie dust and asphalt shingle heat transfer were characterized with a guarded hot plate. Petroleum coke self-heating was consistent with coal, while both poplar pellets and railway tie dust were found to be more reactive compared to oven test results of similar materials. The observed increase in reactivity was probably a result of significant moisture contenint in the pellet and railway tie dust. Critical conditions for spontaneous combustion were evaluated with the Frank-Kamenetskii parameter, assuming an ambient temperature of 40°C and constant moisture content. Kamenetskii calculations indicate that a 1.6 m cube of railway tie dust, or a 58 m cube of asphalt particles, would be unstable and combust. LCF chemistry may have been affected by weathering, which would cause chemical changes that affect their spontaneous combustion properties. Therefore, railway tie wood and roofing asphalt shingle chemistry were investigated by identifying products of 250° and 550°C pyrolysis with py-GC/MS. Railway tie wood pyrolyzates did not show signs of weathering; in contrast, asphalt pyrolysis

  19. Spontaneous Development of Moral Concepts

    Science.gov (United States)

    Siegal, M.

    1975-01-01

    Moral competence is more difficult to attain than scientific competence. Since language comprehension plays a central role in conceptual development, and moral language is difficult to learn, there is a common deficiency in moral conceptual development. This suggests a theory of non-spontaneous solutions to moral problems. (Author/MS)

  20. Spontaneous regression of pulmonary bullae

    International Nuclear Information System (INIS)

    Satoh, H.; Ishikawa, H.; Ohtsuka, M.; Sekizawa, K.

    2002-01-01

    The natural history of pulmonary bullae is often characterized by gradual, progressive enlargement. Spontaneous regression of bullae is, however, very rare. We report a case in which complete resolution of pulmonary bullae in the left upper lung occurred spontaneously. The management of pulmonary bullae is occasionally made difficult because of gradual progressive enlargement associated with abnormal pulmonary function. Some patients have multiple bulla in both lungs and/or have a history of pulmonary emphysema. Others have a giant bulla without emphysematous change in the lungs. Our present case had treated lung cancer with no evidence of local recurrence. He had no emphysematous change in lung function test and had no complaints, although the high resolution CT scan shows evidence of underlying minimal changes of emphysema. Ortin and Gurney presented three cases of spontaneous reduction in size of bulla. Interestingly, one of them had a marked decrease in the size of a bulla in association with thickening of the wall of the bulla, which was observed in our patient. This case we describe is of interest, not only because of the rarity with which regression of pulmonary bulla has been reported in the literature, but also because of the spontaneous improvements in the radiological picture in the absence of overt infection or tumor. Copyright (2002) Blackwell Science Pty Ltd

  1. Shell theorem for spontaneous emission

    DEFF Research Database (Denmark)

    Kristensen, Philip Trøst; Mortensen, Jakob Egeberg; Lodahl, Peter

    2013-01-01

    and therefore is given exactly by the dipole approximation theory. This surprising result is a spontaneous emission counterpart to the shell theorems of classical mechanics and electrostatics and provides insights into the physics of mesoscopic emitters as well as great simplifications in practical calculations....

  2. Silicosis with bilateral spontaneous pneumothorax

    Directory of Open Access Journals (Sweden)

    Fotedar Sanjay

    2010-01-01

    Full Text Available Presentation with simultaneous bilateral pneumothorax is uncommon and usually in the context of secondary spontaneous pneumothorax.The association of pneumothorax and silicosis is infrequent and most cases are unilateral. Bilateral pneumothorax in silicosis is very rare with just a few reports in medical literature.

  3. Prediction of Spontaneous Preterm Birth

    NARCIS (Netherlands)

    Dijkstra, Karolien

    2002-01-01

    Preterm birth is a leading cause of neonatal morbidity and mortality. It is a major goal in obstetrics to lower the incidence of spontaneous preterm birth (SPB) and related neonatal morbidity and mortality. One of the principal objectives is to discover early markers that would allow us to identify

  4. Spontaneous Arterial Dissection.

    Science.gov (United States)

    Brandt, Tobias; Caplan, Louis

    2001-09-01

    There is no controlled study for the best treatment or management of cervico-cerebral artery dissection (CAD). Rationale initial empiric treatment in acute CAD to prevent secondary embolism is partial thromboplastin time (PTT)-guided anticoagulation by intravenous heparin followed by anticoagulation with warfarin. Carotid surgery for treatment of CAD is not recommended anymore with the possible exception of persisting severe stenosis of the proximal internal carotid artery (ICA). There could be use of carotid angioplasty by balloon dilatation and stenting in selected cases of severe cerebral hemodynamic impairment by bilateral CAD. Duration of secondary prophylaxis by anticoagulation is best guided by Doppler sonography follow-up, and should be continued until normalization of blood flow or until at least 1 year after the vessel is occluded. There is no evidence that pseudoaneurysms increase the risk for embolic complication, and there is no evidence for surgery or continuation of anticoagulation in patients with pseudoaneurysms. Caution should be recommended for exercises that involve excessive head movements (eg, bungee jumping, trampoline jumping, and chiropractic maneuvers). The patient should be informed that recurrent rate is low in nonfamilial cases. Doppler sonography is a low-cost and high-sensitivity method for patients at risk.

  5. Fire management strategies to maintain species population processes in a fragmented landscape of fire-interval extremes.

    Science.gov (United States)

    Tulloch, Ayesha I T; Pichancourt, Jean-Baptiste; Gosper, Carl R; Sanders, Angela; Chadès, Iadine

    2016-10-01

    Changed fire regimes have led to declines of fire-regime-adapted species and loss of biodiversity globally. Fire affects population processes of growth, reproduction, and dispersal in different ways, but there is little guidance about the best fire regime(s) to maintain species population processes in fire-prone ecosystems. We use a process-based approach to determine the best range of fire intervals for keystone plant species in a highly modified Mediterranean ecosystem in southwestern Australia where current fire regimes vary. In highly fragmented areas, fires are few due to limited ignitions and active suppression of wildfire on private land, while in highly connected protected areas fires are frequent and extensive. Using matrix population models, we predict population growth of seven Banksia species under different environmental conditions and patch connectivity, and evaluate the sensitivity of species survival to different fire management strategies and burning intervals. We discover that contrasting, complementary patterns of species life-histories with time since fire result in no single best fire regime. All strategies result in the local patch extinction of at least one species. A small number of burning strategies secure complementary species sets depending on connectivity and post-fire growing conditions. A strategy of no fire always leads to fewer species persisting than prescribed fire or random wildfire, while too-frequent or too-rare burning regimes lead to the possible local extinction of all species. In low landscape connectivity, we find a smaller range of suitable fire intervals, and strategies of prescribed or random burning result in a lower number of species with positive growth rates after 100 years on average compared with burning high connectivity patches. Prescribed fire may reduce or increase extinction risk when applied in combination with wildfire depending on patch connectivity. Poor growing conditions result in a significantly

  6. Fire Danger and Fire Weather Records

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Weather Service (formerly Weather Bureau) and Forest Service developed a program to track meteorological conditions conducive to forest fires, resulting...

  7. Wildland fire emissions, carbon, and climate: Modeling fuel consumption

    Science.gov (United States)

    Roger D. Ottmar

    2014-01-01

    Fuel consumption specifies the amount of vegetative biomass consumed during wildland fire. It is a two-stage process of pyrolysis and combustion that occurs simultaneously and at different rates depending on the characteristics and condition of the fuel, weather, topography, and in the case of prescribed fire, ignition rate and pattern. Fuel consumption is the basic...

  8. All fired up

    CERN Multimedia

    CERN Bulletin

    2013-01-01

    Members of the Directorate and their support staff took part in a fire-fighting course organised by the CERN Fire Brigade just before the end-of-year break.  The Bulletin takes a look at the fire-fighting training on offer at CERN.   At CERN the risk of fire can never be under-estimated. In order to train personnel in the use of fire extinguishers, CERN's fire training centre in Prévessin acquired a fire-simulation platform in 2012. On the morning of 17 December 2012, ten members of the CERN directorate and their support staff tried out the platform, following in the footsteps of 400 other members of the CERN community who had already attended the course. The participants were welcomed to the training centre by Gilles Colin, a fire-fighter and instructor, who gave them a 30-minute introduction to general safety and the different types of fire and fire extinguishers, followed by an hour of practical instruction in the simulation facility. There they were able to pract...

  9. Managing wildland fires: integrating weather models into fire projections

    Science.gov (United States)

    Anne M. Rosenthal; Francis Fujioka

    2004-01-01

    Flames from the Old Fire sweep through lands north of San Bernardino during late fall of 2003. Like many Southern California fires, the Old Fire consumed susceptible forests at the urban-wildland interface and spread to nearby city neighborhoods. By incorporating weather models into fire perimeter projections, scientist Francis Fujioka is improving fire modeling as a...

  10. Experimental investigation on spontaneously active hippocampal cultures recorded by means of high-density MEAs: analysis of the spatial resolution effects

    Directory of Open Access Journals (Sweden)

    Alessandro Maccione

    2010-05-01

    Full Text Available Based on experiments performed with high-resolution Active Pixel Sensor microelectrode arrays (APS-MEAs coupled with spontaneously active hippocampal cultures, this work investigates the spatial resolution effects of the neuroelectronic interface on the analysis of the recorded electrophysiological signals. The adopted methodology consists, first, in recording the spontaneous activity at the highest spatial resolution (inter-electrode separation of 21 µm from the whole array of 4096 microelectrodes. Then, the full resolution dataset is spatially down sampled in order to evaluate the effects on raster plot representation, array-wide spike rate (AWSR, mean firing rate (MFR and mean bursting rate (MBR. Furthermore, the effects of the array-to-network relative position are evaluated by shifting a subset of equally spaced electrodes on the entire recorded area. Results highlight that MFR and MBR are particularly influenced by the spatial resolution provided by the neuroelectronic interface. On high-resolution large MEAs, such analysis better represent the time-based parameterization of the network dynamics. Finally, this work suggest interesting capabilities of high-resolution MEAs for spatial-based analysis in dense and low-dense neuronal preparation for investigating signalling at both local and global neuronal circuitries.

  11. A Case of Spontaneously Resolved Bilateral Primary Spontaneous Pneumothorax

    Directory of Open Access Journals (Sweden)

    Hasan Kahraman

    2014-03-01

    Full Text Available A condition of intrapleural air-space accumulation in individuals without any history of trauma or lung disease is called as primary spontaneous pneumothorax (PSP. Sixteen-years-old male patient admitted with complains of chest pain and dyspnea beginning 3 day ago. On physical examination, severity of breath sounds decreased on right side. Chest radiograph was taken and right-sided pneumothorax was detected and tube thoracostomy was inserted. Two months ago the patient referred to a doctor with similar complaints and physical examination and chest radiograph were reported as normal. The radiograph was retrospectively examined and bilateral PSP was detected. We presented the case duo to spontaneous recovery of bilateral PSP is seen very rarely and so contributes data to the literature. In patients admitted to the clinic with chest pain and shortness of breath, pneumothorax should be considered at differential diagnosis.

  12. An assessment of the impact of home safety assessments on fires and fire-related injuries: a case study of Cheshire Fire and Rescue Service.

    Science.gov (United States)

    Arch, B N; Thurston, M N

    2013-06-01

    Deaths and injuries related to fires are largely preventable events. In the UK, a plethora of community-based fire safety initiatives have been introduced over the last 25 years, often led by fire and rescue services, to address this issue. This paper focuses on one such initiative--home safety assessments (HSAs). Cheshire Fire and Rescue Service (in England) implemented a uniquely large-scale HSA intervention. This paper assesses its effectiveness. The impact of HSAs was assessed in relation to three outcomes: accidental dwelling fires (ADFs), ADFs contained and injuries arising from ADFs. A two-period comparison in fire-related rates of incidences in Cheshire between 2002 and 2011 was implemented, using Poisson regression and adjusting for the national temporal trend using a control group comprising the 37 other English non-metropolitan fire-services. Significant reductions were observed in rates of ADFs [incidence rate ratios (IRR): 0.79, 95% confidence interval (CI): 0.74-0.83, P fires contained to room of origin. There is strong evidence to suggest that the intervention was successful in reducing domestic fires and related injuries.

  13. Spontaneous Retropharyngeal Emphysema: A Case Report | Chi ...

    African Journals Online (AJOL)

    ... is a rare clinical condition in pediatric otolaryngology. The predominant symptoms are sore throat, odynophagia, dysphagia, and neck pain. Here, we report a case of spontaneous retropharyngeal emphysema. Keywords: Iatrogenic injury, retropharyngeal emphysema, spontaneous retropharyngeal emphysem, trauma ...

  14. Introducing GFWED: The Global Fire Weather Database

    Science.gov (United States)

    Field, R. D.; Spessa, A. C.; Aziz, N. A.; Camia, A.; Cantin, A.; Carr, R.; de Groot, W. J.; Dowdy, A. J.; Flannigan, M. D.; Manomaiphiboon, K.; hide

    2015-01-01

    The Canadian Forest Fire Weather Index (FWI) System is the mostly widely used fire danger rating system in the world. We have developed a global database of daily FWI System calculations, beginning in 1980, called the Global Fire WEather Database (GFWED) gridded to a spatial resolution of 0.5 latitude by 2-3 longitude. Input weather data were obtained from the NASA Modern Era Retrospective-Analysis for Research and Applications (MERRA), and two different estimates of daily precipitation from rain gauges over land. FWI System Drought Code calculations from the gridded data sets were compared to calculations from individual weather station data for a representative set of 48 stations in North, Central and South America, Europe, Russia,Southeast Asia and Australia. Agreement between gridded calculations and the station-based calculations tended to be most different at low latitudes for strictly MERRA based calculations. Strong biases could be seen in either direction: MERRA DC over the Mato Grosso in Brazil reached unrealistically high values exceeding DCD1500 during the dry season but was too low over Southeast Asia during the dry season. These biases are consistent with those previously identified in MERRAs precipitation, and they reinforce the need to consider alternative sources of precipitation data. GFWED can be used for analyzing historical relationships between fire weather and fire activity at continental and global scales, in identifying large-scale atmosphereocean controls on fire weather, and calibration of FWI-based fire prediction models.

  15. High Temperature Corrosion in Biomass-Fired Boilers

    DEFF Research Database (Denmark)

    Henriksen, Niels; Montgomery, Melanie; Hede Larsen, Ole

    2002-01-01

    condense on superheater components. This gives rise to specific corrosion problems not previously encountered in coal-fired power plants. The type of corrosion attack can be directly ascribed to the composition of the deposit and the metal surface temperature. To avoid such high corrosion rates, woodchip...... has also been utilised as a fuel. Combustion of woodchip results in a smaller amount of ash, and potassium and chlorine are present in lesser amounts. However, significant corrosion rates were still seen. A case study of a woodchip fired boiler is described. The corrosion mechanisms in both straw-fired...... and woodchip fired boilers are discussed....

  16. Spontaneous methicillin-resistant Staphylococcus aureus (MRSA) meningitis.

    Science.gov (United States)

    Longhurst, William D; Sheele, Johnathan M

    2018-05-01

    Spontaneous methicillin-resistant Staphylococcus aureus (MRSA) meningitis is extremely rare and has a high mortality rate. We report a case of MRSA meningitis in an otherwise healthy young adult female with no recent trauma or neurosurgical interventions. Despite antibiotics she suffered a vasculitis-induced cerebral vascular ischemic event. Copyright © 2018 Elsevier Inc. All rights reserved.

  17. Spontaneous Emission Enhancement at Finite-length Metal

    DEFF Research Database (Denmark)

    Filonenko, K.; Willatzen, Morten; Bordo, V.

    2013-01-01

    We study spontaneous emission enhancement of a two-level atomic emitter placed in a dielectric medium near a finite-length cylindrical metal nanowire. We calculate the dependence of the Purcell factor and the normalized decay rate to a continuous spectrum on the nanowire radius for several emitter...

  18. A propulsion injury following a spontaneous electronic cigarette explosion

    Directory of Open Access Journals (Sweden)

    Cherrie Chan Yiru

    2017-05-01

    Full Text Available Electronic cigarettes (e-cigarettes have become increasingly popular at an alarming rate. This coincides with the public perception that they are a safer mean of nicotine consumption. Unregulated devices carry unrecognized safety risks that have led to numerous cases of burns, associating with spontaneous combustions of e-cigarettes.

  19. Nitric Oxide Orchestrates a Power-Law Modulation of Sympathetic Firing Behaviors in Neonatal Rat Spinal Cords

    Directory of Open Access Journals (Sweden)

    Chun-Kuei Su

    2018-03-01

    Full Text Available Nitric oxide (NO is a diffusible gas and has multifarious effects on both pre- and postsynaptic events. As a consequence of complex excitatory and inhibitory integrations, NO effects on neuronal activities are heterogeneous. Using in vitro preparations of neonatal rats that retain the splanchnic sympathetic nerves and the thoracic spinal cord as an experimental model, we report here that either enhancement or attenuation of NO production in the neonatal rat spinal cords could increase, decrease, or not change the spontaneous firing behaviors recorded from splanchnic sympathetic single fibers. To elucidate the mathematical features of NO-mediated heterogeneous responses, the ratios of changes in firing were plotted against their original firing rates. In log-log plots, a linear data distribution demonstrated that NO-mediated heterogeneity in sympathetic firing responses was well described by a power function. Selective antagonists were applied to test if glycinergic, GABAergic, glutamatergic, and cholinergic neurotransmission in the spinal cord are involved in NO-mediated power-law firing modulations (plFM. NO-mediated plFM diminished in the presence of mecamylamine (an open-channel blocker of nicotinic cholinergic receptors, indicating that endogenous nicotinic receptor activities were essential for plFM. Applications of strychnine (a glycine receptor blocker, gabazine (a GABAA receptor blocker, or kynurenate (a broad-spectrum ionotropic glutamate receptor blocker also caused plFM. However, strychnine- or kynurenate-induced plFM was diminished by L-NAME (an NO synthase inhibitor pretreatments, indicating that the involvements of glycine or ionotropic glutamate receptor activities in plFM were secondary to NO signaling. To recapitulate the arithmetic natures of the plFM, the plFM were simulated by firing changes in two components: a step increment and a fractional reduction of their basal firing activities. Ionotropic glutamate receptor

  20. Biomass co-firing

    DEFF Research Database (Denmark)

    Yin, Chungen

    2013-01-01

    Co-firing biomass with fossil fuels in existing power plants is an attractive option for significantly increasing renewable energy resource utilization and reducing CO2 emissions. This chapter mainly discusses three direct co-firing technologies: pulverized-fuel (PF) boilers, fluidized-bed combus......Co-firing biomass with fossil fuels in existing power plants is an attractive option for significantly increasing renewable energy resource utilization and reducing CO2 emissions. This chapter mainly discusses three direct co-firing technologies: pulverized-fuel (PF) boilers, fluidized......-bed combustion (FBC) systems, and grate-firing systems, which are employed in about 50%, 40% and 10% of all the co-firing plants, respectively. Their basic principles, process technologies, advantages, and limitations are presented, followed by a brief comparison of these technologies when applied to biomass co...

  1. Fire safety analysis: methodology

    International Nuclear Information System (INIS)

    Kazarians, M.

    1998-01-01

    From a review of the fires that have occurred in nuclear power plants and the results of fire risk studies that have been completed over the last 17 years, we can conclude that internal fires in nuclear power plants can be an important contributor to plant risk. Methods and data are available to quantify the fire risk. These methods and data have been subjected to a series of reviews and detailed scrutiny and have been applied to a large number of plants. There is no doubt that we do not know everything about fire and its impact on a nuclear power plants. However, this lack of knowledge or uncertainty can be quantified and can be used in the decision making process. In other words, the methods entail uncertainties and limitations that are not insurmountable and there is little or no basis for the results of a fire risk analysis fail to support a decision process

  2. Selected problems of mine ventilation under conditions of gas and fire hazards. [Poland

    Energy Technology Data Exchange (ETDEWEB)

    Rosiek, F; Sikora, M; Urbanski, J

    1984-01-01

    Activities of the the Department for Ventilation, Fires and Occupational Safety in Wroclaw are evaluated. Until 1981 the Department concentrated its research programs on ventilation in copper mines; since 1982 its programs have also covered ventilation and hazards of endogenous fire in black coal mines. The Department investigated hazards of coal spontaneous combustion in Lower Silesian coal mines and proved that the hazards are associated with occurrence of specific layers in coal seams. When coal left in the goaf area came from a layer prone to spontaneous combustion hazards of endogenous fires were high. The Department developed a method for fire prevention using periodic reversal of goaf ventilation. Schemes for reverse ventilation are discussed.

  3. Efficiency of rate and latency coding with respect to metabolic cost and time.

    Science.gov (United States)

    Levakova, Marie

    2017-11-01

    Recent studies on the theoretical performance of latency and rate code in single neurons have revealed that the ultimate accuracy is affected in a nontrivial way by aspects such as the level of spontaneous activity of presynaptic neurons, amount of neuronal noise or the duration of the time window used to determine the firing rate. This study explores how the optimal decoding performance and the corresponding conditions change when the energy expenditure of a neuron in order to spike and maintain the resting membrane potential is accounted for. It is shown that a nonzero amount of spontaneous activity remains essential for both the latency and the rate coding. Moreover, the optimal level of spontaneous activity does not change so much with respect to the intensity of the applied stimulus. Furthermore, the efficiency of the temporal and the rate code converge to an identical finite value if the neuronal activity is observed for an unlimited period of time. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Effects of fire behavior on prescribed fire smoke characteristics: A case study

    International Nuclear Information System (INIS)

    Einfeld, W.; Ward, D.E.; Hardy, C.

    1991-01-01

    In this chapter the authors report results from a study that was designed to derive an estimate of the total release of important pollutant species from a well-characterized fire. Ground and aircraft measurements were coordinated to yield a relatively complete picture of fire behavior and accompanying smoke production. Results from these measurements are then integrated over the lifetime of the fire and compared to less rigorous methods of estimating pollutant yield. Results suggest that knowledge of fuel consumption by phase of combustion (flaming vs. smoldering) is important in making accurate estimates of the characteristics of smoke emissions from individual fires. Contributing factors such as fuel type, fuel loading, and meteorological history vary significantly by region and should be taken into account when compiling estimates of fuel consumption rates during both flaming and smoldering fire conditions

  5. Little Bear Fire Summary Report

    Science.gov (United States)

    Sarah McCaffrey; Melanie Stidham; Hannah. Brenkert-Smith

    2013-01-01

    In June 2012, immediately after the Little Bear Fire burned outside Ruidoso, New Mexico, a team of researchers interviewed fire managers, local personnel, and residents to understand perceptions of the event itself, communication, evacuation, and pre-fire preparedness. The intensity of fire behavior and resulting loss of 242 homes made this a complex fire with a...

  6. Fire management in central America

    Science.gov (United States)

    Andrea L. Koonce; Armando González-Cabán

    1992-01-01

    Information on fire management operations in Central America is scant. To evaluate the known level of fire occurrence in seven countries in that area, fire management officers were asked to provide information on their fire control organizations and on any available fire statistics. The seven countries surveyed were Guatemala, Belize, Honduras, El Salvador, Nicaragua,...

  7. The human and fire connection

    Science.gov (United States)

    Theresa B. Jain

    2014-01-01

    We refer to fire as a natural disturbance, but unlike other disturbances such as forest insects and diseases, fire has had an intimate relationship with humans. Fire facilitated human evolution over two million years ago when our ancestors began to use fire to cook. Fire empowered our furbearers to adapt to cold climates, allowing humans to disperse and settle into...

  8. Forest landowner decisions and the value of information under fire risk.

    Science.gov (United States)

    Gregory S. Amacher; Arun S. Malik; Robert G. Haight

    2005-01-01

    We estimate the value of three types of information about fire risk to a nonindustrial forest landowner: the relationship between fire arrival rates and stand age, the magnitude of fire arrival rates, and the efficacy of fuel reduction treatment. Our model incorporates planting density and the level and timing of fuel reduction treatment as landowner decisions. These...

  9. Wildland Fire Management Plan

    Energy Technology Data Exchange (ETDEWEB)

    Schwager, K. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2017-09-30

    The Wildland Fire Management Plan (FMP) for Brookhaven National Lab (BNL) is written to comply with Department of Energy (DOE) Integrated Safety Management Policy; Federal Wildland Fire Management Policy and Program Review; and Wildland and Prescribed Fire Management Policy and Implementation Procedures Reference Guide. This current plan incorporates changes resulting from new policies on the national level as well as significant changes to available resources and other emerging issues, and replaces BNL's Wildland FMP dated 2014.

  10. Characterizing spontaneous irregular behavior in coupled map lattices

    International Nuclear Information System (INIS)

    Dobyns, York; Atmanspacher, Harald

    2005-01-01

    Two-dimensional coupled map lattices display, in a specific parameter range, a stable phase (quasi-) periodic in both space and time. With small changes to the model parameters, this stable phase develops spontaneous eruptions of non-periodic behavior. Although this behavior itself appears irregular, it can be characterized in a systematic fashion. In particular, parameter-independent features of the spontaneous eruptions may allow useful empirical characterizations of other phenomena that are intrinsically hard to predict and reproduce. Specific features of the distributions of lifetimes and emergence rates of irregular states display such parameter-independent properties

  11. Characterizing spontaneous irregular behavior in coupled map lattices

    Energy Technology Data Exchange (ETDEWEB)

    Dobyns, York [PEAR, Princeton University Princeton, NJ 08544-5263 (United States); Atmanspacher, Harald [Institut fuer Grenzgebiete der Psychologie und Psychohygiene Wilhelmstrasse 3a, Freiburg 79098 (Germany)]. E-mail: haa@igpp.de

    2005-04-01

    Two-dimensional coupled map lattices display, in a specific parameter range, a stable phase (quasi-) periodic in both space and time. With small changes to the model parameters, this stable phase develops spontaneous eruptions of non-periodic behavior. Although this behavior itself appears irregular, it can be characterized in a systematic fashion. In particular, parameter-independent features of the spontaneous eruptions may allow useful empirical characterizations of other phenomena that are intrinsically hard to predict and reproduce. Specific features of the distributions of lifetimes and emergence rates of irregular states display such parameter-independent properties.

  12. The Fire-Walker’s High: Affect and Physiological Responses in an Extreme Collective Ritual

    DEFF Research Database (Denmark)

    Fischer, Ronald; Xygalatas, Dimitris; Mitkidis, Panagiotis

    2014-01-01

    -walking ritual in a Mauritian Hindu community. Specifically, we compared changes in levels of happiness, fatigue, and heart rate reactivity among high-ordeal participants (fire-walkers), low-ordeal participants (non-fire-walking participants with familial bonds to fire-walkers) and spectators (unrelated....../unknown to the fire-walkers). We observed that fire-walkers experienced the highest increase in heart rate and reported greater happiness post-ritual compared to low-ordeal participants and spectators. Low-ordeal participants reported increased fatigue after the ritual compared to both fire-walkers and spectators...

  13. WebFIRE

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Factor Information Retrieval (FIRE) Data System is a database management system containing EPA's recommended emission estimation factors for criteria and...

  14. Fire safety engineering

    International Nuclear Information System (INIS)

    Smith, D.N.

    1989-01-01

    The periodic occurrence of large-scale, potentially disastrous industrial accidents involving fire in hazardous environments such as oilwell blowouts, petrochemical explosions and nuclear installations highlights the need for an integrated approach to fire safety engineering. Risk reduction 'by design' and rapid response are of equal importance in the saving of life and property in such situations. This volume of papers covers the subject thoroughly, touching on such topics as hazard analysis, safety design and testing, fire detection and control, and includes studies of fire hazard in the context of environment protection. (author)

  15. Effects of accelerated wildfire on future fire regimes and implications for the United States federal fire policy

    Directory of Open Access Journals (Sweden)

    Alan A. Ager

    2017-12-01

    Full Text Available Wildland fire suppression practices in the western United States are being widely scrutinized by policymakers and scientists as costs escalate and large fires increasingly affect social and ecological values. One potential solution is to change current fire suppression tactics to intentionally increase the area burned under conditions when risks are acceptable to managers and fires can be used to achieve long-term restoration goals in fire adapted forests. We conducted experiments with the Envision landscape model to simulate increased levels of wildfire over a 50-year period on a 1.2 million ha landscape in the eastern Cascades of Oregon, USA. We hypothesized that at some level of burned area fuels would limit the growth of new fires, and fire effects on the composition and structure of forests would eventually reduce future fire intensity and severity. We found that doubling current rates of wildfire resulted in detectable feedbacks in area burned and fire intensity. Area burned in a given simulation year was reduced about 18% per unit area burned in the prior five years averaged across all scenarios. The reduction in area burned was accompanied by substantially lower fire severity, and vegetation shifted to open forest and grass-shrub conditions at the expense of old growth habitat. Negative fire feedbacks were slightly moderated by longer-term positive feedbacks, in which the effect of prior area burned diminished during the simulation. We discuss trade-offs between managing fuels with wildfire versus prescribed fire and mechanical fuel treatments from a social and policy standpoint. The study provides a useful modeling framework to consider the potential value of fire feedbacks as part of overall land management strategies to build fire resilient landscapes and reduce wildfire risk to communities in the western U.S. The results are also relevant to prior climate-wildfire studies that did not consider fire feedbacks in projections of future

  16. Spontaneous Rotational Inversion in Phycomyces

    KAUST Repository

    Goriely, Alain

    2011-03-01

    The filamentary fungus Phycomyces blakesleeanus undergoes a series of remarkable transitions during aerial growth. During what is known as the stagea IV growth phase, the fungus extends while rotating in a counterclockwise manner when viewed from above (stagea IVa) and then, while continuing to grow, spontaneously reverses to a clockwise rotation (stagea IVb). This phase lasts for 24-48Ah and is sometimes followed by yet another reversal (stageAIVc) before the overall growth ends. Here, we propose a continuum mechanical model of this entire process using nonlinear, anisotropic, elasticity and show how helical anisotropy associated with the cell wall structure can induce spontaneous rotation and, under appropriate circumstances, the observed reversal of rotational handedness. © 2011 American Physical Society.

  17. Spontaneous esophageal-pleural fistula

    OpenAIRE

    Vyas, Sameer; Prakash, Mahesh; Kaman, Lileshwar; Bhardwaj, Nidhi; Khandelwal, Niranjan

    2011-01-01

    Spontaneous esophageal-pleural fistula (EPF) is a rare entity. We describe a case in a middle-aged female who presented with severe retrosternal chest pain and shortness of breadth. Chest computed tomography showed right EPF and hydropneumothorax. She was managed conservatively keeping the chest tube drainage and performing feeding jejunostomy. A brief review of the imaging finding and management of EPF is discussed.

  18. Spontaneous esophageal-pleural fistula.

    Science.gov (United States)

    Vyas, Sameer; Prakash, Mahesh; Kaman, Lileshwar; Bhardwaj, Nidhi; Khandelwal, Niranjan

    2011-10-01

    Spontaneous esophageal-pleural fistula (EPF) is a rare entity. We describe a case in a middle-aged female who presented with severe retrosternal chest pain and shortness of breadth. Chest computed tomography showed right EPF and hydropneumothorax. She was managed conservatively keeping the chest tube drainage and performing feeding jejunostomy. A brief review of the imaging finding and management of EPF is discussed.

  19. Spontaneous esophageal-pleural fistula

    Directory of Open Access Journals (Sweden)

    Sameer Vyas

    2011-01-01

    Full Text Available Spontaneous esophageal-pleural fistula (EPF is a rare entity. We describe a case in a middle-aged female who presented with severe retrosternal chest pain and shortness of breadth. Chest computed tomography showed right EPF and hydropneumothorax. She was managed conservatively keeping the chest tube drainage and performing feeding jejunostomy. A brief review of the imaging finding and management of EPF is discussed.

  20. Spontaneous acute spinal subdural hematoma: spontaneous recovery from severe paraparesis--case report and review.

    Science.gov (United States)

    Payer, Michael; Agosti, Reto

    2010-11-01

    Spontaneous idiopathic acute spinal subdural hematomas are highly exceptional. Neurological symptoms are usually severe, and rapid diagnosis with MRI is mandatory. Surgical evacuation has frequently been used therapeutically; however, spontaneous recovery in mild cases has also been reported. We present a case of spontaneous recovery from severe paraparesis after spontaneous acute SSDH, and review the English-speaking literature.

  1. Spontaneous fission of 259Md

    International Nuclear Information System (INIS)

    Hulet, E.K.; Wild, J.F.; Lougheed, R.W.; Baisden, P.A.; Landrum, J.H.; Dougan, R.J.; Mustafa, M.; Ghiorso, A.; Nitschke, J.M.

    1979-01-01

    The mass and kinetic energy distributions of fission fragments from the spontaneous fission of th newly discovered nuclide 259 Md were obtained. 259 Md was identified as the E. C. daughter of 259 No, and was found to decay entirely (> 95%) by spontaneous fission with a 95-min half-life. From the kinetic energies measured for 397 pairs of coincident fragments, a mass distribution was derived that is symmetric with sigma = 13 amu. 259 Md, together with 258 Fm and 259 Fm, form a select group of three nuclides whose mass division in spontaneous fission is highly symmetric. Unlike the total-kinetic-energy (TKE) distributions of 258 Fm and 259 Fm, which peak at approx. = to 240 MeV, this distribution for 259 Md is broad and is 50 MeV lower in energy. Analysis of the mass and energy distributions shows that events near mass symmetry also exhibit a broad TKE distribution, with one-third of the symmetric events having TKEs less than 200 MeV. The associated of low TKEs with symmetric mass division in the fission of very heavy actinides is anomalous and inconsistent with theories based upon the emergence of fragment shells near the scission point. Either three-body fragmentation or peculiar fragment shapes are assumed as the cause for the large consumption of Coulomb energy observed for a significant fraction of symmetric fissions in 259 Md. 6 figures

  2. Spontaneous Scalarization: Dead or Alive?

    Science.gov (United States)

    Berti, Emanuele; Crispino, Luis; Gerosa, Davide; Gualtieri, Leonardo; Horbatsch, Michael; Macedo, Caio; Okada da Silva, Hector; Pani, Paolo; Sotani, Hajime; Sperhake, Ulrich

    2015-04-01

    In 1993, Damour and Esposito-Farese showed that a wide class of scalar-tensor theories can pass weak-field gravitational tests and exhibit nonperturbative strong-field deviations away from General Relativity in systems involving neutron stars. These deviations are possible in the presence of ``spontaneous scalarization,'' a phase transition similar in nature to spontaneous magnetization in ferromagnets. More than twenty years after the original proposal, binary pulsar experiments have severely constrained the possibility of spontaneous scalarization occurring in nature. I will show that these experimental constraints have important implications for the torsional oscillation frequencies of neutron stars and for the so-called ``I-Love-Q'' relations in scalar-tensor theories. I will also argue that there is still hope to observe strong scalarization effects, despite the strong experimental bounds on the original mechanism. In particular, I will discuss two mechanisms that could produce strong scalarization in neutron stars: anisotropy and multiscalarization. This work was supported by NSF CAREER Award PHY-1055103.

  3. Spontaneous Splenic Rupture in Melanoma

    Directory of Open Access Journals (Sweden)

    Hadi Mirfazaelian

    2014-01-01

    Full Text Available Spontaneous rupture of spleen due to malignant melanoma is a rare situation, with only a few case reports in the literature. This study reports a previously healthy, 30-year-old man who came with chief complaint of acute abdominal pain to emergency room. On physical examination, abdominal tenderness and guarding were detected to be coincident with hypotension. Ultrasonography revealed mild splenomegaly with moderate free fluid in abdominopelvic cavity. Considering acute abdominal pain and hemodynamic instability, he underwent splenectomy with splenic rupture as the source of bleeding. Histologic examination showed diffuse infiltration by tumor. Immunohistochemical study (positive for S100, HMB45, and vimentin and negative for CK, CD10, CK20, CK7, CD30, LCA, EMA, and chromogranin confirmed metastatic malignant melanoma. On further questioning, there was a past history of a nasal dark skin lesion which was removed two years ago with no pathologic examination. Spontaneous (nontraumatic rupture of spleen is an uncommon situation and it happens very rarely due to neoplastic metastasis. Metastasis of malignant melanoma is one of the rare causes of the spontaneous rupture of spleen.

  4. [Treatment of the first episode of spontaneous pneumothorax].

    Science.gov (United States)

    Moubachir, H; Zaghba, N; Benjelloun, H; Bakhatar, A; Yassine, N

    2016-11-01

    The management of a first episode of spontaneous pneumothorax is controversial and the best technique to be used as an initial intervention, aspiration or intercostal drainage, is still debated. We present a retrospective case series during two and a half consecutive years describing the immediate management of spontaneous pneumothoraces, comparing aspiration versus thoracic drainage. One hundred and thirty-three clinical files from patients with spontaneous pneumothoraces were analyzed (17 primary and 116 secondary). The pneumothoraces were of varying size and different etiologies. Patients were initially treated with simple aspiration in 68 cases, with an immediate success rate of 37.5%, intercostal drainage in 49 cases, and by rest alone in 16 cases. In case of secondary pneumothorax, aspiration appeared to offer advantages as an initial strategy over intercostal drainage in terms of hospital stay (11 versus 22 days), and with significant effectiveness (37.5%). Copyright © 2016 SPLF. Published by Elsevier Masson SAS. All rights reserved.

  5. A synthesis of post-fire Burned Area Reports from 1972 to 2009 for western US Forest Service lands: Trends in wildfire characteristics and post-fire stabilisation treatments and expenditures

    Science.gov (United States)

    Peter R. Robichaud; Hakjun Rhee; Sarah A. Lewis

    2014-01-01

    Over 1200 post-fire assessment and treatment implementation reports from four decades (1970s-2000s) of western US forest fires have been examined to identify decadal patterns in fire characteristics and the justifications and expenditures for the post-fire treatments. The main trends found were: (1) the area burned by wildfire increased over time and the rate of...

  6. Thermal surface characteristics of coal fires 1 results of in-situ measurements

    Science.gov (United States)

    Zhang, Jianzhong; Kuenzer, Claudia

    2007-12-01

    Natural underground coal fires are fires in coal seams occurring subsurface. The fires are ignited through a process named spontaneous combustion, which occurs based on a natural reaction but is usually triggered through human interaction. Coal mining activities expose coal to the air. This leads to the exothermal oxidation of the carbon in the coal with the air's oxygen to CO 2 and - under certain circumstances - to spontaneous combustion. Coal fires occur in many countries world wide - however, currently the Chinese coal mining industry faces the biggest problems with coal fires. Coal fires destroy the valuable resource coal and furthermore lead to many environmental degradation phenomena such as the deterioration of surrounding vegetation, land subsidence and the emission of toxic gasses (CO, N 2O). They additionally contribute to the emission of green house relevant gasses such as CO 2 and CH 4 to the atmosphere. In this paper we present thermal characteristics of coal fires as measured in-situ during a field campaign to the Wuda coal fire area in south-central Inner Mongolia, China. Thermal characteristics include temperature anomaly measurements at the surface, spatial surface temperature profiles of fire areas and unaffected background areas, diurnal temperature profiles, and temperature measurements inside of coal fire induced cracks in the overlying bedrock. For all the measurements the effects of uneven solar heating through influences of slope and aspect are considered. Our findings show that coal fires result in strong or subtle thermal surface anomalies. Especially the latter can easily be influenced by heating of the surrounding background material through solar influences. Temperature variation of background rocks with different albedo, slope, aspect or vegetation cover can substantially influence the detectability of thermal anomalies. In the worst case coal fire related thermal anomalies can be completely masked by solar patterns during the daytime

  7. Smoking and Home Fire Safety

    Science.gov (United States)

    ... Materials Working with the Media Fire Protection Technology Smoking fire safety outreach materials As a member of ... Not reported 7% In transport 1% 195 incidents Smoking fire safety messages to share It is important ...

  8. Wireless Sensor Network for Forest Fire Detection 2

    OpenAIRE

    João Gilberto Fernandes Gonçalves Teixeira

    2017-01-01

    The main purpose for this project is the development of a semi-autonomous wireless sensor network for fire detection in remote territory. Making use of the IEEE 802.15.4 standard, a wireless standard for low-power, low-rate wireless sensor networks, a real sensor network and web application will be developed and deployed with the ability to monitor sensor data, detect a fire occurrence and generate early fire alerts.

  9. Adapting fire management to future fire regimes: impacts on boreal forest composition and carbon balance in Canadian National Parks

    Science.gov (United States)

    de Groot, W. J.; Flannigan, M. D.; Cantin, A.

    2009-04-01

    The effects of future fire regimes altered by climate change, and fire management in adaptation to climate change were studied in the boreal forest region of western Canada. Present (1975-90) and future (2080-2100) fire regimes were simulated for several National Parks using data from the Canadian (CGCM1) and Hadley (HadCM3) Global Climate Models (GCM) in separate simulation scenarios. The long-term effects of the different fire regimes on forests were simulated using a stand-level, boreal fire effects model (BORFIRE). Changes in forest composition and biomass storage due to future altered fire regimes were determined by comparing current and future simulation results. This was used to assess the ecological impact of altered fire regimes on boreal forests, and the future role of these forests as carbon sinks or sources. Additional future simulations were run using adapted fire management strategies, including increased fire suppression and the use of prescribed fire to meet fire cycle objectives. Future forest composition, carbon storage and emissions under current and adapted fire management strategies were also compared to determine the impact of various future fire management options. Both of the GCM's showed more severe burning conditions under future fire regimes. This includes fires with higher intensity, greater depth of burn, greater total fuel consumption and shorter fire cycles (or higher rates of annual area burned). The Canadian GCM indicated burning conditions more severe than the Hadley GCM. Shorter fire cycles of future fire regimes generally favoured aspen, birch, and jack pine because it provided more frequent regeneration opportunity for these pioneer species. Black spruce was only minimally influenced by future fire regimes, although white spruce declined sharply. Maintaining representation of pure and mixed white spruce ecosystems in natural areas will be a concern under future fire regimes. Active fire suppression is required in these areas. In

  10. The Application for a Prediction of the Coal Spontaneous Ignition - Predisam

    Science.gov (United States)

    Moni, Vlastimil; Klouda, Petr; Blata, Jan; Helebrant, František

    2017-06-01

    The article follows the research of the project number TA01020351 called "The research of possibilities when predicting steam origin and consequent spontaneous ignition of brown coal fuels" which was researched with the support of the Technological Agency in the Czech Republic in 2011-2014 in the connection with a realized technical research. Therefore, it gives a summary information about the evaluation of the risk degree for the origin of spontaneous ignitions of the brown coal. The presented way of evaluation is based on a numeric expression of a value for MHU criteria - the point load of particular indicators is added together with other results gained from this research project. Then, more information is taken from companies running the dumps of brown coal products - both for suppliers (mining companies) and big consumers (power engineering). The complex knowledge about prediction of the origin of the spontaneous ignition enables to make an early response to eliminate a threat of mining fire in open pit mines or on the dumps of coal products. Consequently, it reduces the risk of fire and breakdowns of transportation means DPD, heavy machines and preparation plants. The working injuries are reduced as well - burns by coal in fire or inhalation of gas products from imperfect combustion.

  11. THE APPLICATION FOR A PREDICTION OF THE COAL SPONTANEOUS IGNITION – PREDISAM

    Directory of Open Access Journals (Sweden)

    Vlastimil MONI

    2017-04-01

    Full Text Available The article follows the research of the project number TA01020351 called “The research of possibilities when predicting steam origin and consequent spontaneous ignition of brown coal fuels” which was researched with the support of the Technological Agency in the Czech Republic in 2011-2014 in the connection with a realized technical research. Therefore, it gives a summary information about the evaluation of the risk degree for the origin of spontaneous ignitions of the brown coal. The presented way of evaluation is based on a numeric expression of a value for MHU criteria – the point load of particular indicators is added together with other results gained from this research project. Then, more information is taken from companies running the dumps of brown coal products – both for suppliers (mining companies and big consumers (power engineering. The complex knowledge about prediction of the origin of the spontaneous ignition enables to make an early response to eliminate a threat of mining fire in open pit mines or on the dumps of coal products. Consequently, it reduces the risk of fire and breakdowns of transportation means DPD, heavy machines and preparation plants. The working injuries are reduced as well – burns by coal in fire or inhalation of gas products from imperfect combustion.

  12. Spontaneous and posed facial expression in Parkinson's disease.

    Science.gov (United States)

    Smith, M C; Smith, M K; Ellgring, H

    1996-09-01

    Spontaneous and posed emotional facial expressions in individuals with Parkinson's disease (PD, n = 12) were compared with those of healthy age-matched controls (n = 12). The intensity and amount of facial expression in PD patients were expected to be reduced for spontaneous but not posed expressions. Emotional stimuli were video clips selected from films, 2-5 min in duration, designed to elicit feelings of happiness, sadness, fear, disgust, or anger. Facial movements were coded using Ekman and Friesen's (1978) Facial Action Coding System (FACS). In addition, participants rated their emotional experience on 9-point Likert scales. The PD group showed significantly less overall facial reactivity than did controls when viewing the films. The predicted Group X Condition (spontaneous vs. posed) interaction effect on smile intensity was found when PD participants with more severe disease were compared with those with milder disease and with controls. In contrast, ratings of emotional experience were similar for both groups. Depression was positively associated with emotion rating but not with measures of facial activity. Spontaneous facial expression appears to be selectively affected in PD, whereas posed expression and emotional experience remain relatively intact.

  13. German private mobile telecommunication research program. Effects of a) low-frequency magnetic fields, b) GSM mobile telecommunication signals, c) UMTS signals on the spontaneous leukemia rate of AKR mice

    International Nuclear Information System (INIS)

    2006-01-01

    Since the introduction of private mobile telecommunication about 10 years ago, there is a worldwide discussion about the possible adverse health effects of such highfrequency electromagnetic fields (EMF). Main concerns are regarding the possible cancerogenic or promoting effect of mobile phones and base stations. The insecurity of the public is increased by the continuous development of new techniques and introduction of new systems (e.g. wireless LAN, UMTS), for which insufficient data are available about their possible health hazards. This project's aim was therefore to investigate if chronic exposure to EMF of the UMTS-standard will influence leukaemia or the development of solid tumors in an animal model. The experiment was performed with AKR mice, which is an accepted animal model for leukaemia. With high probability, these mice develop the disease within their lifespan, so that the time course of the onset of leukaemia, bodyweight, blood picture, time of survival, and pathological examinations were the endpoints of the investigation. 160 female AKR/J mice were exposed or sham-exposed for 24 hours per day to EMF of the UMTS-standard (0.4 W/kg SAR). Additionally, 33 animals were kept as cagecontrols. For this experiment special radial waveguides were constructed and built which have a low SAR variability. All experiments were performed in a blinded fashion. The only significant difference between exposed and sham-exposed mice was a higher survival rate of exposed animals. However, the number of ill animals, the mean survival time and the severity code of the disease did not differ between the experimental groups. Animals of the cage-control group had a significant lower growth rate compared to animals kept in the radial waveguides, likely the cause of differences in the method of food supply. The results of this study don't show any negative effects of the exposure. The results do not show any negative effects of exposure for months to EMF at levels 5-fold the

  14. Post-fire bedload sediment delivery across spatial scales in the interior western United States

    Science.gov (United States)

    Joseph W. Wagenbrenner; Peter R. Robichaud

    2014-01-01

    Post-fire sediment yields can be up to three orders of magnitude greater than sediment yields in unburned forests. Much of the research on post-fire erosion rates has been at small scales (100m2 or less), and post-fire sediment delivery rates across spatial scales have not been quantified in detail. We developed relationships for post-fire bedload sediment delivery...

  15. Hydroxychloroquine reduces heart rate by modulating the hyperpolarization-activated current If: Novel electrophysiological insights and therapeutic potential

    Science.gov (United States)

    Capel, Rebecca A.; Herring, Neil; Kalla, Manish; Yavari, Arash; Mirams, Gary R.; Douglas, Gillian; Bub, Gil; Channon, Keith; Paterson, David J.; Terrar, Derek A.; Burton, Rebecca-Ann B.

    2015-01-01

    Background Bradycardic agents are of interest for the treatment of ischemic heart disease and heart failure, as heart rate is an important determinant of myocardial oxygen consumption. Objectives The purpose of this study was to investigate the propensity of hydroxychloroquine (HCQ) to cause bradycardia. Methods We assessed the effects of HCQ on (1) cardiac beating rate in vitro (mice); (2) the “funny” current (If) in isolated guinea pig sinoatrial node (SAN) myocytes (1, 3, 10 µM); (3) heart rate and blood pressure in vivo by acute bolus injection (rat, dose range 1–30 mg/kg), (4) blood pressure and ventricular function during feeding (mouse, 100 mg/kg/d for 2 wk, tail cuff plethysmography, anesthetized echocardiography). Results In mouse atria, spontaneous beating rate was significantly (P < .05) reduced (by 9% ± 3% and 15% ± 2% at 3 and 10 µM HCQ, n = 7). In guinea pig isolated SAN cells, HCQ conferred a significant reduction in spontaneous action potential firing rate (17% ± 6%, 1 μM dose) and a dose-dependent reduction in If (13% ± 3% at 1 µM; 19% ± 2% at 3 µM). Effects were also observed on L-type calcium ion current (ICaL) (12% ± 4% reduction) and rapid delayed rectifier potassium current (IKr) (35% ± 4%) at 3 µM. Intravenous HCQ decreased heart rate in anesthetized rats (14.3% ± 1.1% at 15mg/kg; n = 6) without significantly reducing mean arterial blood pressure. In vivo feeding studies in mice showed no significant change in systolic blood pressure nor left ventricular function. Conclusions We have shown that HCQ acts as a bradycardic agent in SAN cells, in atrial preparations, and in vivo. HCQ slows the rate of spontaneous action potential firing in the SAN through multichannel inhibition, including that of If. PMID:26025323

  16. Spontaneous Gamma Activity in Schizophrenia.

    Science.gov (United States)

    Hirano, Yoji; Oribe, Naoya; Kanba, Shigenobu; Onitsuka, Toshiaki; Nestor, Paul G; Spencer, Kevin M

    2015-08-01

    A major goal of translational neuroscience is to identify neural circuit abnormalities in neuropsychiatric disorders that can be studied in animal models to facilitate the development of new treatments. Oscillations in the gamma band (30-100 Hz) of the electroencephalogram have received considerable interest as the basic mechanisms underlying these oscillations are understood, and gamma abnormalities have been found in schizophrenia (SZ). Animal models of SZ based on hypofunction of the N-methyl-d-aspartate receptor (NMDAR) demonstrate increased spontaneous broadband gamma power, but this phenomenon has not been identified clearly in patients with SZ. To examine spontaneous gamma power and its relationship to evoked gamma oscillations in the auditory cortex of patients with SZ. We performed a cross-sectional study including 24 patients with chronic SZ and 24 matched healthy control participants at the Veterans Affairs Boston Healthcare System from January 1, 2009, through December 31, 2012. Electroencephalograms were obtained during auditory steady-state stimulation at multiple frequencies (20, 30, and 40 Hz) and during a resting state in 18 participants in each group. Electroencephalographic activity in the auditory cortex was estimated using dipole source localization. Auditory steady-state response (ASSR) measures included the phase-locking factor and evoked power. Spontaneous gamma power was measured as induced (non-phase-locked) gamma power in the ASSR data and as total gamma power in the resting-state data. The ASSR phase-locking factor was reduced significantly in patients with SZ compared with controls for the 40-Hz stimulation (mean [SD], 0.075 [0.028] vs 0.113 [0.065]; F1,46 = 6.79 [P = .012]) but not the 20- or the 30-Hz stimulation (0.042 [0.038] vs 0.043 [0.034]; F1,46 = 0.006 [P = .938] and 0.084 [0.040] vs 0.098 [0.050]; F1,46 = 1.605 [P = .212], respectively), repeating previous findings. The mean [SD] broadband-induced (30

  17. The fire brigade renovates

    CERN Multimedia

    2002-01-01

    The new fire engine at CERN's Fire Station. A shiny brand-new fire engine is now attracting all the attention of the members of CERN's fire brigade. Since the beginning of last week this engine has taken over from an 18-year-old one, which has now been 'retired' from service. This modern vehicle, built in Brescia, Italy, is much lighter and more powerful than the old one and is equipped to allow the fire service to tackle most call-outs without the support of at least one other vehicle, as is currently necessary. The new fire engine is designed to transport six fire-fighters, 2000 litres of water, and is equipped not only for fire fighting actions but also to respond initially to any other kind of call-out, such as traffic accidents, chemical incidents, pollution, lightning, etc. It goes almost without saying that it is provided with the most modern safety measures, a low centre of gravity, as well as a special chassis and a combination pump (low and high pressure), which improve the safety and performance ...

  18. Fire exposed aluminium structures

    NARCIS (Netherlands)

    Maljaars, J.; Fellinger, J.E.J.; Soetens, F.

    2005-01-01

    Material properties and mechanical response models for fire design of steel structures are based on extensive research and experience. Contrarily, the behaviour of aluminium load bearing structures exposed to fire is relatively unexplored. This article gives an overview of physical and mechanical

  19. Advanced fire information system

    CSIR Research Space (South Africa)

    Frost, PE

    2007-01-01

    Full Text Available The South African Advanced Fire Information System (AFIS) is the first near real-time satellite-based fire monitoring system in Africa. It was originally developed for, and funded by, the electrical power utility Eskom, to reduce the impact of wild...

  20. Hot fire, cool soil

    NARCIS (Netherlands)

    Stoof, C.R.; Moore, D.; Fernandes, P.; Stoorvogel, J.J.; Fernandes, R.; Ferreira, A.J.D.; Ritsema, C.J.

    2013-01-01

    Wildfires greatly increase a landscape's vulnerability to flooding and erosion events by removing vegetation and changing soils. Fire damage to soil increases with increasing soil temperature, and, for fires where smoldering combustion is absent, the current understanding is that soil temperatures

  1. Fire Behavior in Pelalawan Peatland, Riau Province

    Directory of Open Access Journals (Sweden)

    BAMBANG HERO SAHARJO

    2006-01-01

    Full Text Available During dry season it is easily recognized that smoke will emerge at certain place both in Sumatra and Kalimantan that is in peatland. The worst situation occurred when fire burnt buried log in the logged over area where the fire fighter did not have any experience and knowledge on how to work with fire in peatland. Finally it had been found that one of the reasons why firefighter failed to fight fire in peatland is because they do not have any knowledge and experience on it. In order to know the fire behavior characteristics in different level of peat decomposition for fire management and sustainable management of the land for the community, research done in Pelalawan area, Riau Province, Indonesia, during dry season 2001. Three level of peat decomposition named Sapric, Hemic, and Fibric used. To conduct the research, two 400 m2 of plot each was established in every level of the peat decomposition. Burning done three weeks following slashing, cutting and drying at different time using circle method. During burning, flame length, rate of the spread of fire, flame temperature and following burning fuel left and the depth of peat destruction were measured. Results of research shown that in sapric site where sapric 2 has fuel load 9 ton ha-1 less than sapric 1, fire behavior was significantly different while peat destructed was deepest in sapric 2 with 31.87 cm. In hemic site where hemic 2 has fuel load 12.3 ton ha-1 more than hemic 1, fire behavior was significantly different and peat destructed deeper than hemic 1 that was 12.6 cm. In fibric site where fibric 1 has fuel load 3.5 ton ha-1 more than fibric 1, fire behavior was significantly different that has no burnt peat found. This results found that the different fuel characteristics (potency, moisture, bed depth, and type at the same level of peat decomposition will have significantly different fire behavior as it happened also on the depth of peat destruction except fibric. The same condition

  2. Advanced numerical modelling of a fire. Final report

    International Nuclear Information System (INIS)

    Heikkilae, L.; Keski-Rahkonen, O.

    1996-03-01

    Experience and probabilistic risk assessments show that fires present a major hazard in a nuclear power plant (NPP). The PALOME project (1988-92) improved the quality of numerical simulation of fires to make it a useful tool for fire safety analysis. Some of the most advanced zone model fire simulation codes were acquired. The performance of the codes was studied through literature and personal interviews in earlier studies and BRI2 code from the Japanese Building Research Institute was selected for further use. In PALOME 2 project this work was continued. Information obtained from large-scale fire tests at the German HDR facility allowed reliable prediction of the rate of heat release and was used for code validation. BRI2 code was validated particularly by participation in the CEC standard problem 'Prediction of effects caused by a cable fire experiment within the HDR-facility'. Participation in the development of a new field model code SOFIE specifically for fire applications as British-Swedish-Finnish cooperation was one of the goals of the project. SOFIE code was implemented at VTT and the first results of validation simulations were obtained. Well instrumented fire tests on electronic cabinets were carried out to determine source terms for simulation of room fires and to estimate fire spread to adjacent cabinets. The particular aim of this study was to measure the rate of heat release from a fire in an electronic cabinet. From the three tests, differing mainly in the amount of the fire load, data was obtained for source terms in numerical modelling of fires in rooms containing electronic cabinets. On the basis of these tests also a simple natural ventilation model was derived. (19 refs.)

  3. Factors Analysis of Spontaneous Abortion after Thawed-vitrified Blastocysts Transfer

    Institute of Scientific and Technical Information of China (English)

    Dong YANG; Zheng-yi SUN; Cheng-yan DENG; Qi YU; Fang-fang HE

    2008-01-01

    Objective To investigate the factors resulting in spontaneous abortion after transferring frozen-thawing blastocysts. Methods A total of 108 cases transferring vitrified blastocysts were divided into two groups: abortion group (n =20) and ongoing group (n=88). Cytogenetic analysis of apoblemas was performed in 12 cases of the abortion.Results The overall spontaneous abortion rate was 18.50%(20/108) and the early spontaneous rate was 16.67%(18/108). ,4 significant difference in maternal age was observed (abortion group: 33.3±4.0 years, ongoing group: 31.0±3.6 years, P=0.02). No difference in other parameters was found. Cytogenetic analysis of apoblemas was obtained for 12 cases, and 2 specimens were contaminated. Seven of ten patients had abnormal karyotypes. Conclusion The underlying cause of spontaneous abortion after transferring frozen thawing blastocysts appears to be abnormal karyotypes.Advancing maternal age seems to increase the risk of spontaneous abortion.

  4. Fires in Chile

    Science.gov (United States)

    2002-01-01

    On February 5, 2002, the dense smoke from numerous forest fires stretched out over the Pacific Ocean about 400 miles south of Santiago, Chile. This true-color Moderate-resolution Imaging Spectroradiometer (MODIS) image shows the fires, which are located near the city of Temuco. The fires are indicated with red dots (boxes in the high-resolution imagery). The fires were burning near several national parks and nature reserves in an area of the Chilean Andes where tourism is very popular. Southeast of the fires, the vegetation along the banks of the Rio Negro in Argentina stands out in dark green. Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC

  5. Sodium fire protection

    International Nuclear Information System (INIS)

    Raju, C.; Kale, R.D.

    1979-01-01

    Results of experiments carried out with sodium fires to develop extinguishment techniques are presented. Characteristics, ignition temperature, heat evolution and other aspects of sodium fires are described. Out of the powders tested for extinguishment of 10 Kg sodium fires, sodium bi-carbonate based dry chemical powder has been found to be the best extinguisher followed by large sized vermiculite and then calcium carbonate powders distributed by spray nozzles. Powders, however, do not extinguish large fires effectively due to sodium-concrete reaction. To control large scale fires in a LMFBR, collection trays with protective cover have been found to cause oxygen starvation better than flooding with inert gas. This system has an added advantage in that there is no damage to the sodium facilities as has been in the case of powders which often contain chlorine compounds and cause stress corrosion cracking. (M.G.B.)

  6. The spontaneous chlorophyll mutation frequency in barley

    DEFF Research Database (Denmark)

    Jørgensen, Jørgen Helms; Jensen, Hans Peter

    1986-01-01

    A total of 1866 barley plants were progeny tested in the greenhouse. Twenty-five plants segregated for newly arisen, spontaneous chlorophyll mutant genes. Among the total of 470,129 seedlings screened there were 79 mutants (1.7 .+-. 0.6 .times. 10-4). The data are added to data from three similar...... materials and the resulting estimate of the chlorophyll mutant frequency is 1.6 .times. 10-4 in about 1.43 million seedlings. The estimate of the chlorophyll mutation rate per generation is close to 67.3 .times. 10-4 per diploid genome or in the order of 6 .times. 10-7 per locus and haploid genome....

  7. Spontaneous charged lipid transfer between lipid vesicles.

    Science.gov (United States)

    Richens, Joanna L; Tyler, Arwen I I; Barriga, Hanna M G; Bramble, Jonathan P; Law, Robert V; Brooks, Nicholas J; Seddon, John M; Ces, Oscar; O'Shea, Paul

    2017-10-03

    An assay to study the spontaneous charged lipid transfer between lipid vesicles is described. A donor/acceptor vesicle system is employed, where neutrally charged acceptor vesicles are fluorescently labelled with the electrostatic membrane probe Fluoresceinphosphatidylethanolamine (FPE). Upon addition of charged donor vesicles, transfer of negatively charged lipid occurs, resulting in a fluorescently detectable change in the membrane potential of the acceptor vesicles. Using this approach we have studied the transfer properties of a range of lipids, varying both the headgroup and the chain length. At the low vesicle concentrations chosen, the transfer follows a first-order process where lipid monomers are transferred presumably through the aqueous solution phase from donor to acceptor vesicle. The rate of transfer decreases with increasing chain length which is consistent with energy models previously reported for lipid monomer vesicle interactions. Our assay improves on existing methods allowing the study of a range of unmodified lipids, continuous monitoring of transfer and simplified experimental procedures.

  8. Spontaneous light emission in complex nanostructures

    Science.gov (United States)

    Blanco, L. A.; García de Abajo, F. J.

    2004-05-01

    The spontaneous emission of an excited atom surrounded by different materials is studied in the framework of a semiclassical approach, where the transition dipole moment acts as the source of the emission field. The emission in the presence of semiinfinite media, metallic nanorings, spheres, gratings, and other complex geometries is investigated. Strong emission enhancement effects are obtained in some of these geometries associated to the excitation of plasmons (e.g., in nanorings or spheres). Furthermore, the emission is shown to take place only along narrow angular distributions when the atom is located inside a low-index dielectric and near its planar surface, or when metallic nanogratings are employed at certain resonant wave lengths. In particular, axially symmetric gratings made of real silver metal are considered, and both emission rate enhancement and focused far-field emission are achieved simultaneously when the grating is decorated with further nanostructures.

  9. Exploring the Future of Fuel Loads in Tasmania, Australia: Shifts in Vegetation in Response to Changing Fire Weather, Productivity, and Fire Frequency

    Directory of Open Access Journals (Sweden)

    Rebecca Mary Bernadette Harris

    2018-04-01

    Full Text Available Changes to the frequency of fire due to management decisions and climate change have the potential to affect the flammability of vegetation, with long-term effects on the vegetation structure and composition. Frequent fire in some vegetation types can lead to transformational change beyond which the vegetation type is radically altered. Such feedbacks limit our ability to project fuel loads under future climatic conditions or to consider the ecological tradeoffs associated with management burns. We present a “pathway modelling” approach to consider multiple transitional pathways that may occur under different fire frequencies. The model combines spatial layers representing current and future fire danger, biomass, flammability, and sensitivity to fire to assess potential future fire activity. The layers are derived from a dynamically downscaled regional climate model, attributes from a regional vegetation map, and information about fuel characteristics. Fire frequency is demonstrated to be an important factor influencing flammability and availability to burn and therefore an important determinant of future fire activity. Regional shifts in vegetation type occur in response to frequent fire, as the rate of change differs across vegetation type. Fire-sensitive vegetation types move towards drier, more fire-adapted vegetation quickly, as they may be irreversibly impacted by even a single fire, and require very long recovery times. Understanding the interaction between climate change and fire is important to identify appropriate management regimes to sustain fire-sensitive communities and maintain the distribution of broad vegetation types across the landscape.

  10. GABAB-receptor activation alters the firing pattern of dopamine neurons in the rat substantia nigra.

    Science.gov (United States)

    Engberg, G; Kling-Petersen, T; Nissbrandt, H

    1993-11-01

    Previous electrophysiological experiments have emphasized the importance of the firing pattern for the functioning of midbrain dopamine (DA) neurons. In this regard, excitatory amino acid receptors appear to constitute an important modulatory control mechanism. In the present study, extracellular recording techniques were used to investigate the significance of GABAB-receptor activation for the firing properties of DA neurons in the substantia nigra (SN) in the rat. Intravenous administration of the GABAB-receptor agonist baclofen (1-16 mg/kg) was associated with a dose-dependent regularization of the firing pattern, concomitant with a reduction in burst firing. At higher doses (16-32 mg/kg), the firing rate of the DA neurons was dose-dependently decreased. Also, microiontophoretic application of baclofen regularized the firing pattern of nigral DA neurons, including a reduction of burst firing. Both the regularization of the firing pattern and inhibition of firing rate produced by systemic baclofen administration was antagonized by the GABAB-receptor antagonist CGP 35348 (200 mg/kg, i.v.). The GABAA-receptor agonist muscimol produced effects on the firing properties of DA neurons that were opposite to those observed following baclofen, i.e., an increase in firing rate accompanied by a decreased regularity. The NMDA receptor antagonist MK 801 (0.4-3.2 mg/kg, i.v.) produced a moderate, dose-dependent increase in the firing rate of the nigral DA neurons as well as a slightly regularized firing pattern. Pretreatment with MK 801 (3.2 mg/kg, i.v., 3-10 min) did neither promote nor prevent the regularization of the firing pattern or inhibition of firing rate on the nigral DA neurons produced by baclofen. The present results clearly show that GABAB-receptors can alter the firing pattern of nigral DA neurons, hereby counterbalancing the previously described ability of glutamate to induce burst firing activity on these neurons.

  11. USFA NFIRS 2005 Basic Fire Incident Data

    Data.gov (United States)

    Department of Homeland Security — The 2005 US Fire Administration Fire (USFA) Fire Incident & Cause Data was provided by the U.S. Fire Administration's (USFA) National Fire Data Center's (NFDC's)...

  12. USFA NFIRS 2008 Basic Fire Incident Data

    Data.gov (United States)

    Department of Homeland Security — The 2008 US Fire Administration Fire (USFA) Fire Incident & Cause Data was provided by the U.S. Fire Administration's (USFA) National Fire Data Center's (NFDC's)...

  13. Fire science at LLNL: A review

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, H.K. (ed.)

    1990-03-01

    This fire sciences report from LLNL includes topics on: fire spread in trailer complexes, properties of welding blankets, validation of sprinkler systems, fire and smoke detectors, fire modeling, and other fire engineering and safety issues. (JEF)

  14. USFA NFIRS 2009 Basic Fire Incident Data

    Data.gov (United States)

    Department of Homeland Security — The 2009 US Fire Administration Fire (USFA) Fire Incident & Cause Data was provided by the U.S. Fire Administration's (USFA) National Fire Data Center's (NFDC's)...

  15. Position-dependent patterning of spontaneous action potentials in immature cochlear inner hair cells

    Science.gov (United States)

    Johnson, Stuart L.; Eckrich, Tobias; Kuhn, Stephanie; Zampini, Valeria; Franz, Christoph; Ranatunga, Kishani M.; Roberts, Terri P.; Masetto, Sergio; Knipper, Marlies; Kros, Corné J.; Marcotti, Walter

    2011-01-01

    Spontaneous action potential activity is crucial for mammalian sensory system development. In the auditory system, patterned firing activity has been observed in immature spiral ganglion cells and brain-stem neurons and is likely to depend on cochlear inner hair cell (IHC) action potentials. It remains uncertain whether spiking activity is intrinsic to developing IHCs and whether it shows patterning. We found that action potentials are intrinsically generated by immature IHCs of altricial rodents and that apical IHCs exhibit bursting activity as opposed to more sustained firing in basal cells. We show that the efferent neurotransmitter ACh, by fine-tuning the IHC’s resting membrane potential (Vm), is crucial for the bursting pattern in apical cells. Endogenous extracellular ATP also contributes to the Vm of apical and basal IHCs by activating SK2 channels. We hypothesize that the difference in firing pattern along the cochlea instructs the tonotopic differentiation of IHCs and auditory pathway. PMID:21572434

  16. Pilot fire radius size and its variation regarding the uncertainty in fire risk assessment

    International Nuclear Information System (INIS)

    Argirov, J.

    1998-01-01

    The impact of a combustible load with limited amount of heat on the characteristics of fire generated local environment is considered. The combustible load apportionment on the floor and its ability to release the heat at a different rate regarding the temperatures and heat flux in zones formed in the NPP compartments is studied using calculations. Several ways of variation of a pilot fire radius in the same range are compared. (author)

  17. Fire Risk Assessment in Germany

    International Nuclear Information System (INIS)

    Berg, H. P.

    2000-01-01

    Quantitative fire risk assessment can serve as an additional tool to assess the safety level of a nuclear power plant (NPP) and to set priorities for fire protection improvement measures. The recommended approach to be applied within periodic safety reviews of NPPs in Germany starts with a screening process providing critical fire zones in which a fully developed fire has the potential to both cause an initiating event and impair the function of at least one component or system critical to safety. The second step is to perform a quantitative analysis using a standard event tree has been developed with elements for fire initiation, ventilation of the room, fire detection, fire suppression, and fire propagation. In a final step, the fire induced frequency of initiating events, the main contributors and the calculated hazard state frequency for the fire event are determined. Results of the first quantitative fire risk studies performed in Germany are reported. (author)

  18. Fire protection for clean rooms

    International Nuclear Information System (INIS)

    Kirson, D.

    1990-01-01

    The fire protection engineer often must decide what size fire can be tolerated before automatic fire suppression systems actuate. Is it a wastepaper basket fire, a bushel basket fire...? In the case of state-of-the-art clean rooms, the answer clearly is not even an incipient fire. Minor fires in clean rooms can cause major losses. This paper discusses what a clean room is and gives a brief overview of the unique fire protection challenges encountered. The two major causes of fire related to clean rooms in the semiconductor industry are flammable/pyrophoric gas fires in plastic ducts and polypropylene wet bench fires. This paper concentrates on plastic ductwork in clean rooms, sprinkler protection in ductwork, and protection for wet benches

  19. Spontaneous coronary dissection: case report

    OpenAIRE

    Couto, Gustavo J. Ventura; Deslandes, Alexandre de O.; Santos, Paulo César de Souza; Cruz, Alexandre de Araújo; Saraiva, Roberto Santos

    2007-01-01

    O objetivo do trabalho é demonstrar o caso de um homem de 62 anos, com quadro de dissecção coronariana espontânea, localizada em 1/3 inicial de coronária circunflexa esquerda, tratado cirurgicamente com revascularização miocárdica. A operação realizada com sucesso demonstra, nesse caso, ser o único meio possível de cura.The purpose of the paper is to demonstrate the case of a 62-year-old man, with spontaneous coronary dissection of the left circumflex artery, treated surgically by myocardial ...

  20. [Spontaneous neoplasms in guinea pigs].

    Science.gov (United States)

    Khar'kovskaia, N A; Khrustalev, S A; Vasil'eva, N N

    1977-01-01

    The authors present an analysis of the data of foreign literature and the results of their personal studies of spontaneous neoplasms in 40 guinea pigs of national breeding observed during observed during a 5-year period. In 4 of them malignant tumors were diagnosed-lympholeucosis (2 cases), dermoid ovarian cysts and also cancer and adenoma of the adrenal cortex (in one animal). The neoplasms described developed in guinea pigs, aged over 4 years, and they are referred to as mostly common tumors in this species of animals.