Discrimination of shot-noise-driven Poisson processes by external dead time - Application of radioluminescence from glass

NASA Technical Reports Server (NTRS)

Saleh, B. E. A.; Tavolacci, J. T.; Teich, M. C.

1981-01-01

Ways in which dead time can be used to constructively enhance or diminish the effects of point processes that display bunching in the shot-noise-driven doubly stochastic Poisson point process (SNDP) are discussed. Interrelations between photocount bunching arising in the SNDP and the antibunching character arising from dead-time effects are investigated. It is demonstrated that the dead-time-modified count mean and variance for an arbitrary doubly stochastic Poisson point process can be obtained from the Laplace transform of the single-fold and joint-moment-generating functions for the driving rate process. The theory is in good agreement with experimental values for radioluminescence radiation in fused silica, quartz, and glass, and the process has many applications in pulse, particle, and photon detection.

Scientific evidence of the therapeutic effects of dead sea treatments: a systematic review.

PubMed

Katz, Uriel; Shoenfeld, Yehuda; Zakin, Varda; Sherer, Yaniv; Sukenik, Shaul

2012-10-01

The Dead Sea, the deepest and most saline lake on earth, has been known from biblical times for its healing properties. The aim of this systematic review was to present critically the level of evidence for the claims of therapeutic effects of Dead Sea treatments in several rheumatologic diseases and psoriasis as well as to review these treatments' safety. All articles cited in MEDLINE under the query, "Dead Sea," were reviewed. We found bona fide evidence that Dead Sea treatments are especially effective in psoriasis due to both the special characteristics of solar ultraviolet radiation in the Dead Sea and the Dead Sea water balneotherapy. Dead Sea mud and Dead Sea balneotherapy have been found to be beneficial in rheumatologic diseases, including rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, and knee osteoarthritis. In the safety analysis, we found no evidence for an increase in skin neoplasia, although skin actinic damage seems to be increased in patients treated in the Dead Sea. Dead Sea treatments do not lead to worsening of blood pressure. Substantial ingestion of Dead Sea water (generally in unusual near-drowning cases) is toxic and can result in cardiac rhythm disturbances because of electrolyte concentration abnormalities. Laboratory analysis of Dead Sea mud did not reveal mineral concentrations that could represent a health concern for their intended use. Dead Sea treatments are beneficial in several rheumatologic diseases and psoriasis and have a good safety profile. Copyright © 2012 Elsevier Inc. All rights reserved.

Modeling decay rates of dead wood in a neotropical forest.

PubMed

Hérault, Bruno; Beauchêne, Jacques; Muller, Félix; Wagner, Fabien; Baraloto, Christopher; Blanc, Lilian; Martin, Jean-Michel

2010-09-01

Variation of dead wood decay rates among tropical trees remains one source of uncertainty in global models of the carbon cycle. Taking advantage of a broad forest plot network surveyed for tree mortality over a 23-year period, we measured the remaining fraction of boles from 367 dead trees from 26 neotropical species widely varying in wood density (0.23-1.24 g cm(-3)) and tree circumference at death time (31.5-272.0 cm). We modeled decay rates within a Bayesian framework assuming a first order differential equation to model the decomposition process and tested for the effects of forest management (selective logging vs. unexploited), of mode of death (standing vs. downed) and of topographical levels (bottomlands vs. hillsides vs. hilltops) on wood decay rates. The general decay model predicts the observed remaining fraction of dead wood (R2 = 60%) with only two biological predictors: tree circumference at death time and wood specific density. Neither selective logging nor local topography had a differential effect on wood decay rates. Including the mode of death into the model revealed that standing dead trees decomposed faster than downed dead trees, but the gain of model accuracy remains rather marginal. Overall, these results suggest that the release of carbon from tropical dead trees to the atmosphere can be simply estimated using tree circumference at death time and wood density.

The effects of a western spruce budworm outbreak on the dead wood component in relation to ownership in forests of eastern Oregon

Treesearch

David Azuma

2010-01-01

Forest Inventory and Analysis data were used to investigate the effects of a severe western spruce budworm outbreak on the dead wood component of forests in 11 counties of eastern Oregon for two time periods. The ownership and the level of damage (as assessed by aerial surveys) affected the resulting down woody material and standing dead trees. The pattern of coarse...

YALINA-booster subcritical assembly pulsed-neutron e xperiments: detector dead time and apatial corrections.

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

Cao, Y.; Gohar, Y.; Nuclear Engineering Division

In almost every detector counting system, a minimal dead time is required to record two successive events as two separated pulses. Due to the random nature of neutron interactions in the subcritical assembly, there is always some probability that a true neutron event will not be recorded because it occurs too close to the preceding event. These losses may become rather severe for counting systems with high counting rates, and should be corrected before any utilization of the experimental data. This report examines the dead time effects for the pulsed neutron experiments of the YALINA-Booster subcritical assembly. The nonparalyzable modelmore » is utilized to correct the experimental data due to dead time. Overall, the reactivity values are increased by 0.19$ and 0.32$ after the spatial corrections for the YALINA-Booster 36% and 21% configurations respectively. The differences of the reactivities obtained with He-3 long or short detectors at the same detector channel diminish after the dead time corrections of the experimental data for the 36% YALINA-Booster configuration. In addition, better agreements between reactivities obtained from different experimental data sets are also observed after the dead time corrections for the 21% YALINA-Booster configuration.« less

40 CFR Appendix II to Part 1068 - Emission-Related Parameters and Specifications

Code of Federal Regulations, 2014 CFR

2014-07-01

... valve lash dimension. 4. Camshaft timing. a. Valve opening—intake exhaust (degrees from top-dead center or bottom-dead center). b. Valve closing—intake exhaust (degrees from top-dead center or bottom-dead.... Opening timing (degrees from top-dead center or bottom-dead center). c. Closing timing (degrees from top...

40 CFR Appendix II to Part 1068 - Emission-Related Parameters and Specifications

Code of Federal Regulations, 2012 CFR

2012-07-01

... valve lash dimension. 4. Camshaft timing. a. Valve opening—intake exhaust (degrees from top-dead center or bottom-dead center). b. Valve closing—intake exhaust (degrees from top-dead center or bottom-dead.... Opening timing (degrees from top-dead center or bottom-dead center). c. Closing timing (degrees from top...

40 CFR Appendix II to Part 1068 - Emission-Related Parameters and Specifications

Code of Federal Regulations, 2013 CFR

2013-07-01

... valve lash dimension. 4. Camshaft timing. a. Valve opening—intake exhaust (degrees from top-dead center or bottom-dead center). b. Valve closing—intake exhaust (degrees from top-dead center or bottom-dead.... Opening timing (degrees from top-dead center or bottom-dead center). c. Closing timing (degrees from top...

Role of More Active Identification of Brain-Dead Cases in Increasing Organ Donation.

PubMed

Sadegh Beigee, Farahnaz; Mohsenzadeh, Mojtaba; Shahryari, Shagin; Mojtabaee, Meysam

2017-02-01

Organ donor shortage is a worldwide problem, resulting in 10% to 30% mortality rates for patients on wait lists for organ transplant. For brain-dead patients in Iran, it is mandatory for intensive care unit patients with Glasgow Coma Scale below 5/15 to be reported to an organ procurement unit. However, this process has not been functioning effectively. Here, we present the effects of changing the strategies on detecting brain-dead cases on the organ donor pool. From March 2015 to March 2016, we changed our strategy in active detection of brain-dead cases. Since March 2015, our newly established protocol for active detection of brain-dead cases includes the following changes: (1) instead of calling high-volume intensive care units 3 times per week, we switched to calling every day in the morning; (2) instead of calling low-volume intensive care units 1 time per week, we switched to calling 3 times per week; (3) we included intensive care units (cardiac and general), neurosurgery, and emergency departments, as well as nursing supervisor offices, in our call and visit lists; and (4) we increased visits to wards by our trained staff as inspectors. From March 2015 to March 2016, the number of reported suspected brain-dead cases has increased from 224 to 460 per year, with proven brain death increasing from 180 to 306 cases. The actual number of donors has also increased, from 116 to 165 donations (53% increase) over 1 year. More proactive strategies have had significant effects on brain-dead detection, resulting in significantly increased donor pools and organ donations. In countries with low cooperation of hospital staff, more proactive engagement in detecting brain-dead cases is a good solution to prevent loss of potential organ donors, with a final result of decreasing wait list mortality.

Adaptive NN tracking control of uncertain nonlinear discrete-time systems with nonaffine dead-zone input.

PubMed

Liu, Yan-Jun; Tong, Shaocheng

2015-03-01

In the paper, an adaptive tracking control design is studied for a class of nonlinear discrete-time systems with dead-zone input. The considered systems are of the nonaffine pure-feedback form and the dead-zone input appears nonlinearly in the systems. The contributions of the paper are that: 1) it is for the first time to investigate the control problem for this class of discrete-time systems with dead-zone; 2) there are major difficulties for stabilizing such systems and in order to overcome the difficulties, the systems are transformed into an n-step-ahead predictor but nonaffine function is still existent; and 3) an adaptive compensative term is constructed to compensate for the parameters of the dead-zone. The neural networks are used to approximate the unknown functions in the transformed systems. Based on the Lyapunov theory, it is proven that all the signals in the closed-loop system are semi-globally uniformly ultimately bounded and the tracking error converges to a small neighborhood of zero. Two simulation examples are provided to verify the effectiveness of the control approach in the paper.

40 CFR Appendix II to Part 1068 - Emission-Related Parameters and Specifications

Code of Federal Regulations, 2011 CFR

2011-07-01

... dimension. 4. Camshaft timing. a. Valve opening—intake exhaust (degrees from top-dead center or bottom-dead center). b. Valve closing—intake exhaust (degrees from top-dead center or bottom-dead center). c. Valve... (degrees from top-dead center or bottom-dead center). c. Closing timing (degrees from top-dead center or...

40 CFR Appendix II to Part 1068 - Emission-Related Parameters and Specifications

Code of Federal Regulations, 2010 CFR

2010-07-01

... dimension. 4. Camshaft timing. a. Valve opening—intake exhaust (degrees from top-dead center or bottom-dead center). b. Valve closing—intake exhaust (degrees from top-dead center or bottom-dead center). c. Valve... (degrees from top-dead center or bottom-dead center). c. Closing timing (degrees from top-dead center or...

Inhomogeneous Poisson process rate function inference from dead-time limited observations.

PubMed

Verma, Gunjan; Drost, Robert J

2017-05-01

The estimation of an inhomogeneous Poisson process (IHPP) rate function from a set of process observations is an important problem arising in optical communications and a variety of other applications. However, because of practical limitations of detector technology, one is often only able to observe a corrupted version of the original process. In this paper, we consider how inference of the rate function is affected by dead time, a period of time after the detection of an event during which a sensor is insensitive to subsequent IHPP events. We propose a flexible nonparametric Bayesian approach to infer an IHPP rate function given dead-time limited process realizations. Simulation results illustrate the effectiveness of our inference approach and suggest its ability to extend the utility of existing sensor technology by permitting more accurate inference on signals whose observations are dead-time limited. We apply our inference algorithm to experimentally collected optical communications data, demonstrating the practical utility of our approach in the context of channel modeling and validation.

Analysis of dead zone sources in a closed-loop fiber optic gyroscope.

PubMed

Chong, Kyoung-Ho; Choi, Woo-Seok; Chong, Kil-To

2016-01-01

Analysis of the dead zone is among the intensive studies in a closed-loop fiber optic gyroscope. In a dead zone, a gyroscope cannot detect any rotation and produces a zero bias. In this study, an analysis of dead zone sources is performed in simulation and experiments. In general, the problem is mainly due to electrical cross coupling and phase modulation drift. Electrical cross coupling is caused by interference between modulation voltage and the photodetector. The cross-coupled signal produces spurious gyro bias and leads to a dead zone if it is larger than the input rate. Phase modulation drift as another dead zone source is due to the electrode contamination, the piezoelectric effect of the LiNbO3 substrate, or to organic fouling. This modulation drift lasts for a short or long period of time like a lead-lag filter response and produces gyro bias error, noise spikes, or dead zone. For a more detailed analysis, the cross-coupling effect and modulation phase drift are modeled as a filter and are simulated in both the open-loop and closed-loop modes. The sources of dead zone are more clearly analyzed in the simulation and experimental results.

A Unified Approach to Adaptive Neural Control for Nonlinear Discrete-Time Systems With Nonlinear Dead-Zone Input.

PubMed

Liu, Yan-Jun; Gao, Ying; Tong, Shaocheng; Chen, C L Philip

2016-01-01

In this paper, an effective adaptive control approach is constructed to stabilize a class of nonlinear discrete-time systems, which contain unknown functions, unknown dead-zone input, and unknown control direction. Different from linear dead zone, the dead zone, in this paper, is a kind of nonlinear dead zone. To overcome the noncausal problem, which leads to the control scheme infeasible, the systems can be transformed into a m -step-ahead predictor. Due to nonlinear dead-zone appearance, the transformed predictor still contains the nonaffine function. In addition, it is assumed that the gain function of dead-zone input and the control direction are unknown. These conditions bring about the difficulties and the complicacy in the controller design. Thus, the implicit function theorem is applied to deal with nonaffine dead-zone appearance, the problem caused by the unknown control direction can be resolved through applying the discrete Nussbaum gain, and the neural networks are used to approximate the unknown function. Based on the Lyapunov theory, all the signals of the resulting closed-loop system are proved to be semiglobal uniformly ultimately bounded. Moreover, the tracking error is proved to be regulated to a small neighborhood around zero. The feasibility of the proposed approach is demonstrated by a simulation example.

Two-degree-of-freedom fractional order-PID controllers design for fractional order processes with dead-time.

PubMed

Li, Mingjie; Zhou, Ping; Zhao, Zhicheng; Zhang, Jinggang

2016-03-01

Recently, fractional order (FO) processes with dead-time have attracted more and more attention of many researchers in control field, but FO-PID controllers design techniques available for the FO processes with dead-time suffer from lack of direct systematic approaches. In this paper, a simple design and parameters tuning approach of two-degree-of-freedom (2-DOF) FO-PID controller based on internal model control (IMC) is proposed for FO processes with dead-time, conventional one-degree-of-freedom control exhibited the shortcoming of coupling of robustness and dynamic response performance. 2-DOF control can overcome the above weakness which means it realizes decoupling of robustness and dynamic performance from each other. The adjustable parameter η2 of FO-PID controller is directly related to the robustness of closed-loop system, and the analytical expression is given between the maximum sensitivity specification Ms and parameters η2. In addition, according to the dynamic performance requirement of the practical system, the parameters η1 can also be selected easily. By approximating the dead-time term of the process model with the first-order Padé or Taylor series, the expressions for 2-DOF FO-PID controller parameters are derived for three classes of FO processes with dead-time. Moreover, compared with other methods, the proposed method is simple and easy to implement. Finally, the simulation results are given to illustrate the effectiveness of this method. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Dead wood biomass and turnover time, measured by radiocarbon, along a subalpine elevation gradient.

PubMed

Kueppers, Lara M; Southon, John; Baer, Paul; Harte, John

2004-12-01

Dead wood biomass can be a substantial fraction of stored carbon in forest ecosystems, and coarse woody debris (CWD) decay rates may be sensitive to climate warming. We used an elevation gradient in Colorado Rocky Mountain subalpine forest to examine climate and species effects on dead wood biomass, and on CWD decay rate. Using a new radiocarbon approach, we determined that the turnover time of lodgepole pine CWD (340+/-130 years) was roughly half as long in a site with 2.5-3 degrees C warmer air temperature, as that of pine (630+/-400 years) or Engelmann spruce CWD (800+/-960 and 650+/-410 years) in cooler sites. Across all sites and both species, CWD age ranged from 2 to 600 years, and turnover time was 580+/-180 years. Total standing and fallen dead wood biomass ranged from 4.7+/-0.2 to 54+/-1 Mg ha(-1), and from 2.8 to 60% of aboveground live tree biomass. Dead wood biomass increased 75 kg ha(-1) per meter gain in elevation and decreased 13 Mg ha(-1) for every degree C increase in mean air temperature. Differences in biomass and decay rates along the elevation gradient suggest that climate warming will lead to a loss of dead wood carbon from subalpine forest.

Deciphering The Fall And Rise Of The Dead Sea In Relation To Solar Forcing

NASA Astrophysics Data System (ADS)

Yousef, Shahinaz M.

2005-03-01

Solar Forcing on closed seas and Lakes is space time dependent. The Cipher of the Dead Sea level variation since 1200 BC is solved in the context of millenium and Wolf-Gleissberg solar cycles time scales. It is found that the pattern of Dead Sea level variation follows the pattern of major millenium solar cycles. The 70 m rise of Dead Sea around 1AD is due to the forcing of the maximum millenium major solar cycle. Although the pattern of the Dead Sea level variation is almost identical to major solar cycles pattern between 1100 and 1980 AD, there is a dating problem of the Dead Sea time series around 1100-1300 AD that time. A discrepancy that should be corrected for the solar and Dead Sea series to fit. Detailed level variations of the Dead Sea level for the past 200 years are solved in terms of the 80-120 years solar Wolf-Gliessberg magnetic cycles. Solar induced climate changes do happen at the turning points of those cycles. Those end-start and maximum turning points are coincident with the change in the solar rotation rate due to the presence of weak solar cycles. Such weak cycles occur in series of few cycles between the end and start of those Wolf-Gleissberg cycles. Another one or two weak r solar cycle occur following the maximum of those Wolf-Gleissberg cycles. Weak cycles induce drop in the energy budget emitted from the sun and reaching the Earth thus causing solar induced climate change. An 8 meter sudden rise of Dead Sea occur prior 1900 AD due to positive solar forcing of the second cycle of the weak cycles series on the Dead Sea. The same second weak cycle induced negative solar forcing on Lake Chad. The first weak solar cycle forced Lake Victoria to rise abruptly in 1878. The maximum turning point of the solar Wolf-Gleissberg cycle induced negative forcing on both the Aral Sea and the Dead Sea causing their shrinkage to an alarming reduced area ever since. On the other hand, few years delayed positive forcing caused Lake Chad and the Equatorial African lakes to rise abruptly by several meters. Since the present solar cycle number 23 is the first weak cycle of a series, and since it caused 1.6 m sharp rise in Lake Victoria in 1997, then there is a high probability that the Dead Sea will rise by the beginning of the second weak cycle in few years time. And since both the Aral Sea and the Dead Sea are very much in coherence since the late 1950s, then it is rather likely that the Aral Sea will rise with God's wish in the near future. However it is also demanded that Israel should allow more water of the Jordan River to feed the Dead Sea before its real death. Plans for joining the Dead sea to the Red and or to the Mediterranean Seas should be cancelled owing the damaging harm it will cause the Dead Sea as a perfect indicator of solar induced climate change on one hand. On the other hand, the Dead Sea time series always show abrupt changes that can be as high as 70 m; if we add to this a planned artificial rise of the Dead Sea to its level of the thirties, then a damaging flooding effect will ruin the establishments and environment greatly.

NO TIME FOR DEAD TIME: TIMING ANALYSIS OF BRIGHT BLACK HOLE BINARIES WITH NuSTAR

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

Bachetti, Matteo; Barret, Didier; Harrison, Fiona A.

Timing of high-count-rate sources with the NuSTAR Small Explorer Mission requires specialized analysis techniques. NuSTAR was primarily designed for spectroscopic observations of sources with relatively low count rates rather than for timing analysis of bright objects. The instrumental dead time per event is relatively long (∼2.5 msec) and varies event-to-event by a few percent. The most obvious effect is a distortion of the white noise level in the power density spectrum (PDS) that cannot be easily modeled with standard techniques due to the variable nature of the dead time. In this paper, we show that it is possible to exploitmore » the presence of two completely independent focal planes and use the cospectrum, the real part of the cross PDS, to obtain a good proxy of the white-noise-subtracted PDS. Thereafter, one can use a Monte Carlo approach to estimate the remaining effects of dead time, namely, a frequency-dependent modulation of the variance and a frequency-independent drop of the sensitivity to variability. In this way, most of the standard timing analysis can be performed, albeit with a sacrifice in signal-to-noise ratio relative to what would be achieved using more standard techniques. We apply this technique to NuSTAR observations of the black hole binaries GX 339–4, Cyg X-1, and GRS 1915+105.« less

Unified dead-time compensation structure for SISO processes with multiple dead times.

PubMed

Normey-Rico, Julio E; Flesch, Rodolfo C C; Santos, Tito L M

2014-11-01

This paper proposes a dead-time compensation structure for processes with multiple dead times. The controller is based on the filtered Smith predictor (FSP) dead-time compensator structure and it is able to control stable, integrating, and unstable processes with multiple input/output dead times. An equivalent model of the process is first computed in order to define the predictor structure. Using this equivalent model, the primary controller and the predictor filter are tuned to obtain an internally stable closed-loop system which also attempts some closed-loop specifications in terms of set-point tracking, disturbance rejection, and robustness. Some simulation case studies are used to illustrate the good properties of the proposed approach. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

77 FR 64373 - Culturally Significant Objects Imported for Exhibition Determinations: “The Dead Sea Scrolls...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-19

... Determinations: ``The Dead Sea Scrolls: Life and Faith in Ancient Times,'' Formerly Titled ``The Dead Sea Scrolls... the Department of State pertaining to the exhibition ``The Dead Sea Scrolls: Life and Faith in Biblical Times.'' The referenced notice is corrected here to change the exhibition name to ``The Dead Sea...

78 FR 62354 - Culturally Significant Objects Imported for Exhibition Determinations: “The Dead Sea Scrolls...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-10-18

... Determinations: ``The Dead Sea Scrolls: Life and Faith in Ancient Times'' Formerly Titled ``The Dead Sea Scrolls... Department of State pertaining to the exhibition ``The Dead Sea Scrolls: Life and Faith in Biblical Times... of the Federal Register (volume 77, number 203) to change the exhibition name to ``The Dead Sea...

78 FR 24462 - Culturally Significant Objects Imported for Exhibition; Determinations: “The Dead Sea Scrolls...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-25

...; Determinations: ``The Dead Sea Scrolls: Life and Faith in Ancient Times'' Formerly Titled ``The Dead Sea Scrolls... Department of State pertaining to the exhibition ``The Dead Sea Scrolls: Life and Faith in Biblical Times... of the Federal Register (volume 77, number 203) to change the exhibition name to ``The Dead Sea...

78 FR 16565 - Culturally Significant Objects Imported for Exhibition Determinations: “The Dead Sea Scrolls...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-15

... Determinations: ``The Dead Sea Scrolls: Life and Faith in Ancient Times'' Formerly Titled ``The Dead Sea Scrolls... Department of State pertaining to the exhibition ``The Dead Sea Scrolls: Life and Faith in Biblical Times... of the Federal Register (volume 77, number 203) to change the exhibition name to ``The Dead Sea...

Are major reductions in new HIV infections possible with people who inject drugs? The case for low dead-space syringes in highly affected countries.

PubMed

Zule, William A; Cross, Harry E; Stover, John; Pretorius, Carel

2013-01-01

Circumstantial evidence from laboratory studies, mathematical models, ecological studies and bio behavioural surveys, suggests that injection-related HIV epidemics may be averted or reversed if people who inject drugs (PWID) switch from using high dead-space to using low dead-space syringes. In laboratory experiments that simulated the injection process and rinsing with water, low dead space syringes retained 1000 times less blood than high dead space syringes. In mathematical models, switching PWID from high dead space to low dead space syringes prevents or reverses injection-related HIV epidemics. No one knows if such an intervention is feasible or what effect it would have on HIV transmission among PWID. Feasibility studies and randomized controlled trials (RCTs) will be needed to answer these questions definitively, but these studies will be very expensive and take years to complete. Rather than waiting for them to be completed, we argue for an approach similar to that used with needle and syringe programs (NSP), which were promoted and implemented before being tested more rigorously. Before implementation, rapid assessments that involve PWID will need to be conducted to ensure buy-in from PWID and other local stakeholders. This commentary summarizes the existing evidence regarding the protective effects of low dead space syringes and estimates potential impacts on HIV transmission; it describes potential barriers to transitioning PWID from high dead space to low dead space needles and syringes; and it presents strategies for overcoming these barriers. Copyright © 2012 Elsevier B.V. All rights reserved.

Detection of Only Viable Bacterial Spores Using a Live/Dead Indicator in Mixed Populations

NASA Technical Reports Server (NTRS)

Behar, Alberto E.; Stam, Christina N.; Smiley, Ronald

2013-01-01

This method uses a photoaffinity label that recognizes DNA and can be used to distinguish populations of bacterial cells from bacterial spores without the use of heat shocking during conventional culture, and live from dead bacterial spores using molecular-based methods. Biological validation of commercial sterility using traditional and alternative technologies remains challenging. Recovery of viable spores is cumbersome, as the process requires substantial incubation time, and the extended time to results limits the ability to quickly evaluate the efficacy of existing technologies. Nucleic acid amplification approaches such as PCR (polymerase chain reaction) have shown promise for improving time to detection for a wide range of applications. Recent real-time PCR methods are particularly promising, as these methods can be made at least semi-quantitative by correspondence to a standard curve. Nonetheless, PCR-based methods are rarely used for process validation, largely because the DNA from dead bacterial cells is highly stable and hence, DNA-based amplification methods fail to discriminate between live and inactivated microorganisms. Currently, no published method has been shown to effectively distinguish between live and dead bacterial spores. This technology uses a DNA binding photoaffinity label that can be used to distinguish between live and dead bacterial spores with detection limits ranging from 109 to 102 spores/mL. An environmental sample suspected of containing a mixture of live and dead vegetative cells and bacterial endospores is treated with a photoaffinity label. This step will eliminate any vegetative cells (live or dead) and dead endospores present in the sample. To further determine the bacterial spore viability, DNA is extracted from the spores and total population is quantified by real-time PCR. The current NASA standard assay takes 72 hours for results. Part of this procedure requires a heat shock step at 80 degC for 15 minutes before the sample can be plated. Using a photoaffinity label would remove this step from the current assay as the label readily penetrates both live and dead bacterial cells. Secondly, the photoaffinity label can only penetrate dead bacterial spores, leaving behind the viable spore population. This would allow for rapid bacterial spore detection in a matter of hours compared to the several days that it takes for the NASA standard assay.

Dead time corrections for inbeam γ-spectroscopy measurements

NASA Astrophysics Data System (ADS)

Boromiza, M.; Borcea, C.; Negret, A.; Olacel, A.; Suliman, G.

2017-08-01

Relatively high counting rates were registered in a proton inelastic scattering experiment on 16O and 28Si using HPGe detectors which was performed at the Tandem facility of IFIN-HH, Bucharest. In consequence, dead time corrections were needed in order to determine the absolute γ-production cross sections. Considering that the real counting rate follows a Poisson distribution, the dead time correction procedure is reformulated in statistical terms. The arriving time interval between the incoming events (Δt) obeys an exponential distribution with a single parameter - the average of the associated Poisson distribution. We use this mathematical connection to calculate and implement the dead time corrections for the counting rates of the mentioned experiment. Also, exploiting an idea introduced by Pommé et al., we describe a consistent method for calculating the dead time correction which completely eludes the complicated problem of measuring the dead time of a given detection system. Several comparisons are made between the corrections implemented through this method and by using standard (phenomenological) dead time models and we show how these results were used for correcting our experimental cross sections.

A note on the effects of replenishment of depleted cells on HIV infection dynamics: A graph-theoretic approach

NASA Astrophysics Data System (ADS)

Mukwembi, Simon

2008-02-01

We study the effects of the rate of replacement of dead cells by either healthy cells or by infected cells on HIV infection dynamics through a graph-theoretic approach. Our framework takes into account a reasonable amount of the immune action to any pathogen and the local cell interactions that occur in the lymph nodes. Our results, in an extremal case where dead cells are highly likely to be replaced by healthy cells, show that all cells become healthy in a finite number of steps of given order and infection stops propagating. Further, for this extremal case, we give an algebraic formula for the number of infected cells at any given time in the HIV progression. We also find a sufficient condition, determined by dead cell replacement rate, which guarantees that an infected patient is continually positive, and give bounds on the number of infected, healthy and dead cells at any given time. We apply our theoretical results to a recently proposed model of the HIV infection dynamics.

Effects of detector dead-time on quantitative analyses involving boron and multi-hit detection events in atom probe tomography.

PubMed

Meisenkothen, Frederick; Steel, Eric B; Prosa, Ty J; Henry, Karen T; Prakash Kolli, R

2015-12-01

In atom probe tomography (APT), some elements tend to field evaporate preferentially in multi-hit detection events. Boron (B) is one such element. It is thought that a large fraction of the B signal may be lost during data acquisition and is not reported in the mass spectrum or in the 3-D APT reconstruction. Understanding the relationship between the field evaporation behavior of B and the limitations for detecting multi-hit events can provide insight into the signal loss mechanism for B and may suggest ways to improve B detection accuracy. The present work reports data for nominally pure B and for B-implanted silicon (Si) (NIST-SRM2137) at dose levels two-orders of magnitude lower than previously studied by Da Costa, et al. in 2012. Boron concentration profiles collected from SRM2137 specimens qualitatively confirmed a signal loss mechanism is at work in laser pulsed atom probe measurements of B in Si. Ion correlation analysis was used to graphically demonstrate that the detector dead-time results in few same isotope, same charge-state (SISCS) ion pairs being properly recorded in the multi-hit data, explaining why B is consistently under-represented in quantitative analyses. Given the important role of detector dead-time as a signal loss mechanism, the results from three different methods of estimating the detector dead-time are presented. The findings of this study apply to all quantitative analyses that involve multi-hit data, but the dead-time will have the greatest effect on the elements that have a significant quantity of ions detected in multi-hit events. Published by Elsevier B.V.

Foehn-induced effects on local dust pollution, frontal clouds and solar radiation in the Dead Sea valley

NASA Astrophysics Data System (ADS)

Kishcha, Pavel; Starobinets, Boris; Savir, Amit; Alpert, Pinhas; Kaplan, Michael

2018-06-01

Despite the long history of investigation of foehn phenomena, there are few studies of the influence of foehn winds on air pollution and none in the Dead Sea valley. For the first time the foehn phenomenon and its effects on local dust pollution, frontal cloudiness and surface solar radiation were analyzed in the Dead Sea valley, as it occurred on 22 March 2013. This was carried out using both numerical simulations and observations. The foehn winds intensified local dust emissions, while the foehn-induced temperature inversion trapped dust particles beneath this inversion. These two factors caused extreme surface dust concentration in the western Dead Sea valley. The dust pollution was transported by west winds eastward, to the central Dead Sea valley, where the speed of these winds sharply decreased. The transported dust was captured by the ascending airflow contributing to the maximum aerosol optical depth (AOD) over the central Dead Sea valley. On the day under study, the maximum surface dust concentration did not coincide with the maximum AOD: this being one of the specific effects of the foehn phenomenon on dust pollution in the Dead Sea valley. Radar data showed a passage of frontal cloudiness through the area of the Dead Sea valley leading to a sharp drop in noon solar radiation. The descending airflow over the downwind side of the Judean Mountains led to the formation of a cloud-free band followed by only the partial recovery of solar radiation because of the extreme dust pollution caused by foehn winds.

Multi-Rate Acquisition for Dead Time Reduction in Magnetic Resonance Receivers: Application to Imaging With Zero Echo Time.

PubMed

Marjanovic, Josip; Weiger, Markus; Reber, Jonas; Brunner, David O; Dietrich, Benjamin E; Wilm, Bertram J; Froidevaux, Romain; Pruessmann, Klaas P

2018-02-01

For magnetic resonance imaging of tissues with very short transverse relaxation times, radio-frequency excitation must be immediately followed by data acquisition with fast spatial encoding. In zero-echo-time (ZTE) imaging, excitation is performed while the readout gradient is already on, causing data loss due to an initial dead time. One major dead time contribution is the settling time of the filters involved in signal down-conversion. In this paper, a multi-rate acquisition scheme is proposed to minimize dead time due to filtering. Short filters and high output bandwidth are used initially to minimize settling time. With increasing time since the signal onset, longer filters with better frequency selectivity enable stronger signal decimation. In this way, significant dead time reduction is accomplished at only a slight increase in the overall amount of output data. Multi-rate acquisition was implemented with a two-stage filter cascade in a digital receiver based on a field-programmable gate array. In ZTE imaging in a phantom and in vivo, dead time reduction by multi-rate acquisition is shown to improve image quality and expand the feasible bandwidth while increasing the amount of data collected by only a few percent.

Reduction of Endotracheal Tube Connector Dead Space Improves Ventilation: A Bench Test on a Model Lung Simulating an Extremely Low Birth Weight Neonate.

PubMed

Ivanov, Vadim A

2016-02-01

The reduction of instrumental dead space is a recognized approach to preventing ventilation-induced lung injury in premature infants. However, there are no published data regarding the effectiveness of instrumental dead-space reduction in endotracheal tube (ETT) connectors. We tested the impact of the Y-piece/ETT connector pairs with reduced instrumental dead space on CO2 elimination in a model of the premature neonate lung. The standard ETT connector was compared with a low-dead-space ETT connector and with a standard connector equipped with an insert. We compared the setups by measuring the CO2 elimination rate in an artificial lung ventilated via the connectors. The lung was connected to a ventilator via a standard circuit, a 2.5-mm ETT, and one of the connectors under investigation. The ventilator was run in volume-controlled continuous mandatory ventilation mode. The low-dead-space ETT connector/Y-piece and insert-equipped standard connector/Y-piece pairs had instrumental dead space reduced by 36 and 67%, respectively. With set tidal volumes (VT) of 2.5, 5, and 10 mL, in comparison with the standard ETT connector, the low-dead-space connector reduced CO2 elimination time by 4.5% (P < .05), 4.4% (P < .01), and 7.1% (not significant), respectively. The insert-equipped standard connector reduced CO2 elimination time by 13.5, 25.1, and 16.1% (all P < .01). The low-dead-space connector increased inspiratory resistance by 17.8% (P < .01), 9.6% (P < .05), and 5.0% (not significant); the insert-equipped standard connector increased inspiratory resistance by 9.1, 8.4, and 5.9% (all not significant). The low-dead-space connector decreased expiratory resistance by 6.8% (P < .01) and 1.8% (not significant) and increased it by 1.4% (not significant); the insert-equipped standard connector decreased expiratory resistance by 1.5 and 1% and increased it by 1% (all not significant). The low-dead-space connector increased work of breathing by 4.7% (P < .01), 3.8% (P < .01), and 2.5% (not significant); the insert-equipped standard connector increased it by 0.8% (not significant), 2.5% (P < .01), and 2.8% (P < .01). Both methods of instrumental dead-space reduction led to improvements in artificial lung ventilation. Negative effects on resistance and work of breathing appeared minimal. Further testing in vivo should be performed to confirm the lung model results and, if successful, translated into clinical practice. Copyright © 2016 by Daedalus Enterprises.

[Spatial pattern of land surface dead combustible fuel load in Huzhong forest area in Great Xing'an Mountains].

PubMed

Liu, Zhi-Hua; Chang, Yu; Chen, Hong-Wei; Zhou, Rui; Jing, Guo-Zhi; Zhang, Hong-Xin; Zhang, Chang-Meng

2008-03-01

By using geo-statistics and based on time-lag classification standard, a comparative study was made on the land surface dead combustible fuels in Huzhong forest area in Great Xing'an Mountains. The results indicated that the first level land surface dead combustible fuel, i. e., 1 h time-lag dead fuel, presented stronger spatial auto-correlation, with an average of 762.35 g x m(-2) and contributing to 55.54% of the total load. Its determining factors were species composition and stand age. The second and third levels land surface dead combustible fuel, i. e., 10 h and 100 h time-lag dead fuels, had a sum of 610.26 g x m(-2), and presented weaker spatial auto-correlation than 1 h time-lag dead fuel. Their determining factor was the disturbance history of forest stand. The complexity and heterogeneity of the factors determining the quality and quantity of forest land surface dead combustible fuels were the main reasons for the relatively inaccurate interpolation. However, the utilization of field survey data coupled with geo-statistics could easily and accurately interpolate the spatial pattern of forest land surface dead combustible fuel loads, and indirectly provide a practical basis for forest management.

Absolute dose calibration of an X-ray system and dead time investigations of photon-counting techniques

NASA Astrophysics Data System (ADS)

Carpentieri, C.; Schwarz, C.; Ludwig, J.; Ashfaq, A.; Fiederle, M.

2002-07-01

High precision concerning the dose calibration of X-ray sources is required when counting and integrating methods are compared. The dose calibration for a dental X-ray tube was executed with special dose calibration equipment (dosimeter) as function of exposure time and rate. Results were compared with a benchmark spectrum and agree within ±1.5%. Dead time investigations with the Medipix1 photon-counting chip (PCC) have been performed by rate variations. Two different types of dead time, paralysable and non-paralysable will be discussed. The dead time depends on settings of the front-end electronics and is a function of signal height, which might lead to systematic defects of systems. Dead time losses in excess of 30% have been found for the PCC at 200 kHz absorbed photons per pixel.

Simulation of Simple Controlled Processes with Dead-Time.

ERIC Educational Resources Information Center

Watson, Keith R.; And Others

1985-01-01

The determination of closed-loop response of processes containing dead-time is typically not covered in undergraduate process control, possibly because the solution by Laplace transforms requires the use of Pade approximation for dead-time, which makes the procedure lengthy and tedious. A computer-aided method is described which simplifies the…

How dead is dead? Qualitative findings from participants of combined traditional and lead-time time trade-off valuations.

PubMed

Al Sayah, Fatima; Mladenovic, Ana; Gaebel, Kathryn; Xie, Feng; Johnson, Jeffrey A

2016-01-01

The EuroQol Valuation Technology (EQ-VT) uses traditional time trade-off (tTTO) for health states better than dead and lead-time TTO (LT-TTO) for states worse than dead to elicit a value (-1.0 to +1.0) for each health state. In the Canadian EQ-5D-5L Valuation study which used the EQVT platform, we observed an unexpected peak in frequency of "0" values and few negative values, particularly in the range of 0 to -0.5. To better understand this finding, we sought to explore respondents' thought processes while valuing a health state, and their understanding of the tTTO and LT-TTO exercises. Qualitative semi-structured interviews were conducted with EQVT task respondents. Questions focused on valuations of health states as: (a) Same as dead in tTTO, (b) Worse than dead in tTTO but changed to same as dead in LT-TTO, (c) Worse than dead in LT-TTO, and (d) Worse than dead in LT-TTO with trading off all 10 years. Data were analyzed using content and thematic analysis. Mean age of participants (N = 70) was 40 ± 18.1 years, 60% female, and 76% Caucasian. Participants provided similar reasons for valuing a health state same as or worse than dead. Many participants expressed confusion about worse than dead valuations, distinction between same as and worse than dead, and the transition from tTTO to LT-TTO. A few indicated that the addition of 10 years of full health in the LT-TTO influenced their valuations. The transition from tTTO to LT-TTO in the EQVT was confusing to participants, whereby some health state valuations around this transition appeared to be arbitrary.

A seamless acquisition digital storage oscilloscope with three-dimensional waveform display

NASA Astrophysics Data System (ADS)

Yang, Kuojun; Tian, Shulin; Zeng, Hao; Qiu, Lei; Guo, Lianping

2014-04-01

In traditional digital storage oscilloscope (DSO), sampled data need to be processed after each acquisition. During data processing, the acquisition is stopped and oscilloscope is blind to the input signal. Thus, this duration is called dead time. With the rapid development of modern electronic systems, the effect of infrequent events becomes significant. To capture these occasional events in shorter time, dead time in traditional DSO that causes the loss of measured signal needs to be reduced or even eliminated. In this paper, a seamless acquisition oscilloscope without dead time is proposed. In this oscilloscope, three-dimensional waveform mapping (TWM) technique, which converts sampled data to displayed waveform, is proposed. With this technique, not only the process speed is improved, but also the probability information of waveform is displayed with different brightness. Thus, a three-dimensional waveform is shown to the user. To reduce processing time further, parallel TWM which processes several sampled points simultaneously, and dual-port random access memory based pipelining technique which can process one sampling point in one clock period are proposed. Furthermore, two DDR3 (Double-Data-Rate Three Synchronous Dynamic Random Access Memory) are used for storing sampled data alternately, thus the acquisition can continue during data processing. Therefore, the dead time of DSO is eliminated. In addition, a double-pulse test method is adopted to test the waveform capturing rate (WCR) of the oscilloscope and a combined pulse test method is employed to evaluate the oscilloscope's capture ability comprehensively. The experiment results show that the WCR of the designed oscilloscope is 6 250 000 wfms/s (waveforms per second), the highest value in all existing oscilloscopes. The testing results also prove that there is no dead time in our oscilloscope, thus realizing the seamless acquisition.

A seamless acquisition digital storage oscilloscope with three-dimensional waveform display

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

Yang, Kuojun, E-mail: kuojunyang@gmail.com; Guo, Lianping; School of Electrical and Electronic Engineering, Nanyang Technological University

In traditional digital storage oscilloscope (DSO), sampled data need to be processed after each acquisition. During data processing, the acquisition is stopped and oscilloscope is blind to the input signal. Thus, this duration is called dead time. With the rapid development of modern electronic systems, the effect of infrequent events becomes significant. To capture these occasional events in shorter time, dead time in traditional DSO that causes the loss of measured signal needs to be reduced or even eliminated. In this paper, a seamless acquisition oscilloscope without dead time is proposed. In this oscilloscope, three-dimensional waveform mapping (TWM) technique, whichmore » converts sampled data to displayed waveform, is proposed. With this technique, not only the process speed is improved, but also the probability information of waveform is displayed with different brightness. Thus, a three-dimensional waveform is shown to the user. To reduce processing time further, parallel TWM which processes several sampled points simultaneously, and dual-port random access memory based pipelining technique which can process one sampling point in one clock period are proposed. Furthermore, two DDR3 (Double-Data-Rate Three Synchronous Dynamic Random Access Memory) are used for storing sampled data alternately, thus the acquisition can continue during data processing. Therefore, the dead time of DSO is eliminated. In addition, a double-pulse test method is adopted to test the waveform capturing rate (WCR) of the oscilloscope and a combined pulse test method is employed to evaluate the oscilloscope's capture ability comprehensively. The experiment results show that the WCR of the designed oscilloscope is 6 250 000 wfms/s (waveforms per second), the highest value in all existing oscilloscopes. The testing results also prove that there is no dead time in our oscilloscope, thus realizing the seamless acquisition.« less

Erratum to “Estimating the effective system dead time parameter for correlated neutron counting” [Nucl. Instrum. Methods Phys. Res. A 871 (2017) 154–160

DOE PAGES

Croft, S.; Cleveland, S.; Favalli, A.; ...

2018-02-23

The expressions given for φ, the ratio of effective system dead time to gate width, are wrong for the case of the third and fourth order forms because the simple square root is used when the 3rd and 4th roots, respectively, are required. We failed to notice during proof reading that this change from the submitted manuscript had crept in. The correct form should, however, be clear from the steps of the derivations outlined in the text; and so we hope our mistake has not misled anyone.

Erratum to “Estimating the effective system dead time parameter for correlated neutron counting” [Nucl. Instrum. Methods Phys. Res. A 871 (2017) 154–160

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

Croft, S.; Cleveland, S.; Favalli, A.

The expressions given for φ, the ratio of effective system dead time to gate width, are wrong for the case of the third and fourth order forms because the simple square root is used when the 3rd and 4th roots, respectively, are required. We failed to notice during proof reading that this change from the submitted manuscript had crept in. The correct form should, however, be clear from the steps of the derivations outlined in the text; and so we hope our mistake has not misled anyone.

An experimental test of the habitat-amount hypothesis for saproxylic beetles in a forested region.

PubMed

Seibold, Sebastian; Bässler, Claus; Brandl, Roland; Fahrig, Lenore; Förster, Bernhard; Heurich, Marco; Hothorn, Torsten; Scheipl, Fabian; Thorn, Simon; Müller, Jörg

2017-06-01

The habitat-amount hypothesis challenges traditional concepts that explain species richness within habitats, such as the habitat-patch hypothesis, where species number is a function of patch size and patch isolation. It posits that effects of patch size and patch isolation are driven by effects of sample area, and thus that the number of species at a site is basically a function of the total habitat amount surrounding this site. We tested the habitat-amount hypothesis for saproxylic beetles and their habitat of dead wood by using an experiment comprising 190 plots with manipulated patch sizes situated in a forested region with a high variation in habitat amount (i.e., density of dead trees in the surrounding landscape). Although dead wood is a spatio-temporally dynamic habitat, saproxylic insects have life cycles shorter than the time needed for habitat turnover and they closely track their resource. Patch size was manipulated by adding various amounts of downed dead wood to the plots (~800 m³ in total); dead trees in the surrounding landscape (~240 km 2 ) were identified using airborne laser scanning (light detection and ranging). Over 3 yr, 477 saproxylic species (101,416 individuals) were recorded. Considering 20-1,000 m radii around the patches, local landscapes were identified as having a radius of 40-120 m. Both patch size and habitat amount in the local landscapes independently affected species numbers without a significant interaction effect, hence refuting the island effect. Species accumulation curves relative to cumulative patch size were not consistent with either the habitat-patch hypothesis or the habitat-amount hypothesis: several small dead-wood patches held more species than a single large patch with an amount of dead wood equal to the sum of that of the small patches. Our results indicate that conservation of saproxylic beetles in forested regions should primarily focus on increasing the overall amount of dead wood without considering its spatial arrangement. This means dead wood should be added wherever possible including in local landscapes with low or high dead-wood amounts. For species that have disappeared from most forests owing to anthropogenic habitat degradation, this should, however, be complemented by specific conservation measures pursued within their extant distributional ranges. © 2017 by the Ecological Society of America.

Improving the counting efficiency in time-correlated single photon counting experiments by dead-time optimization

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

Peronio, P.; Acconcia, G.; Rech, I.

Time-Correlated Single Photon Counting (TCSPC) has been long recognized as the most sensitive method for fluorescence lifetime measurements, but often requiring “long” data acquisition times. This drawback is related to the limited counting capability of the TCSPC technique, due to pile-up and counting loss effects. In recent years, multi-module TCSPC systems have been introduced to overcome this issue. Splitting the light into several detectors connected to independent TCSPC modules proportionally increases the counting capability. Of course, multi-module operation also increases the system cost and can cause space and power supply problems. In this paper, we propose an alternative approach basedmore » on a new detector and processing electronics designed to reduce the overall system dead time, thus enabling efficient photon collection at high excitation rate. We present a fast active quenching circuit for single-photon avalanche diodes which features a minimum dead time of 12.4 ns. We also introduce a new Time-to-Amplitude Converter (TAC) able to attain extra-short dead time thanks to the combination of a scalable array of monolithically integrated TACs and a sequential router. The fast TAC (F-TAC) makes it possible to operate the system towards the upper limit of detector count rate capability (∼80 Mcps) with reduced pile-up losses, addressing one of the historic criticisms of TCSPC. Preliminary measurements on the F-TAC are presented and discussed.« less

High-rate dead-time corrections in a general purpose digital pulse processing system

PubMed Central

Abbene, Leonardo; Gerardi, Gaetano

2015-01-01

Dead-time losses are well recognized and studied drawbacks in counting and spectroscopic systems. In this work the abilities on dead-time correction of a real-time digital pulse processing (DPP) system for high-rate high-resolution radiation measurements are presented. The DPP system, through a fast and slow analysis of the output waveform from radiation detectors, is able to perform multi-parameter analysis (arrival time, pulse width, pulse height, pulse shape, etc.) at high input counting rates (ICRs), allowing accurate counting loss corrections even for variable or transient radiations. The fast analysis is used to obtain both the ICR and energy spectra with high throughput, while the slow analysis is used to obtain high-resolution energy spectra. A complete characterization of the counting capabilities, through both theoretical and experimental approaches, was performed. The dead-time modeling, the throughput curves, the experimental time-interval distributions (TIDs) and the counting uncertainty of the recorded events of both the fast and the slow channels, measured with a planar CdTe (cadmium telluride) detector, will be presented. The throughput formula of a series of two types of dead-times is also derived. The results of dead-time corrections, performed through different methods, will be reported and discussed, pointing out the error on ICR estimation and the simplicity of the procedure. Accurate ICR estimations (nonlinearity < 0.5%) were performed by using the time widths and the TIDs (using 10 ns time bin width) of the detected pulses up to 2.2 Mcps. The digital system allows, after a simple parameter setting, different and sophisticated procedures for dead-time correction, traditionally implemented in complex/dedicated systems and time-consuming set-ups. PMID:26289270

On the interaction of vortices and internal waves in the dead-water problem

NASA Astrophysics Data System (ADS)

Hester, Eric

2017-11-01

Dead water refers to a mysterious increase in resistance experienced by boats in density-stratified waters. The problem has been documented since ancient times, and studied scientifically for over a century. These investigations have revealed the role of internal waves in generating drag. However, analytical approaches neglect important vortex dynamics, which experiments fail to visualise. For the first time, we study the phenomenon using state-of-the-art numerical simulations. We reproduce the effect and show it is greatest in strongly nonlinear regimes poorly modelled by current theory. The most exciting development found a new trailing vortex coupled to the boat. This robust structure is consistent with sailors accounts, but has been missed in previous scientific studies. We expect these results to lead to actionable ways to mitigate dead water in the real world.

Dealing with the health state 'dead' when using discrete choice experiments to obtain values for EQ-5D-5L heath states.

PubMed

Ramos-Goñi, Juan Manuel; Rivero-Arias, Oliver; Errea, María; Stolk, Elly A; Herdman, Michael; Cabasés, Juan Manuel

2013-07-01

To evaluate two different methods to obtain a dead (0)--full health (1) scale for EQ-5D-5L valuation studies when using discrete choice (DC) modeling. The study was carried out among 400 respondents from Barcelona who were representative of the Spanish population in terms of age, sex, and level of education. The DC design included 50 pairs of health states in five blocks. Participants were forced to choose between two EQ-5D-5L states (A and B). Two extra questions concerned whether A and B were considered worse than dead. Each participant performed ten choice exercises. In addition, values were collected using lead-time trade-off (lead-time TTO), for which 100 states in ten blocks were selected. Each participant performed five lead-time TTO exercises. These consisted of DC models offering the health state 'dead' as one of the choices--for which all participants' responses were used (DCdead)--and a model that included only the responses of participants who chose at least one state as worse than dead (WTD) (DCWTD). The study also estimated DC models rescaled with lead-time TTO data and a lead-time TTO linear model. The DC(dead) and DCWTD models produced relatively similar results, although the coefficients in the DCdead model were slightly lower. The DC model rescaled with lead-time TTO data produced higher utility decrements. Lead-time TTO produced the highest utility decrements. The incorporation of the state 'dead' in the DC models produces results in concordance with DC models that do not include 'dead'.

Can dead bacterial cells be defined and are genes expressed after cell death?

PubMed

Trevors, J T

2012-07-01

There is a paucity of knowledge on gene expression in dead bacterial cells. Why would this knowledge be useful? The cells are dead. However, the time duration of gene expression following cell death is often unknown, and possibly in the order of minutes. In addition, it is a challenge to determine if bacterial cells are dead, or viable but non-culturable (VBNC), and what is an agreed upon correct definition of dead bacteria. Cells in the bacterial population or community may die at different rates or times and this complicates both the viability and gene expression analysis. In this article, the definition of dead bacterial cells is discussed and its significance in continued gene expression in cells following death. The definition of living and dead has implications for possible, completely, synthetic bacterial cells that may be capable of growth and division. Copyright © 2012 Elsevier B.V. All rights reserved.

Finding the global minimum: a fuzzy end elimination implementation

NASA Technical Reports Server (NTRS)

Keller, D. A.; Shibata, M.; Marcus, E.; Ornstein, R. L.; Rein, R.

1995-01-01

The 'fuzzy end elimination theorem' (FEE) is a mathematically proven theorem that identifies rotameric states in proteins which are incompatible with the global minimum energy conformation. While implementing the FEE we noticed two different aspects that directly affected the final results at convergence. First, the identification of a single dead-ending rotameric state can trigger a 'domino effect' that initiates the identification of additional rotameric states which become dead-ending. A recursive check for dead-ending rotameric states is therefore necessary every time a dead-ending rotameric state is identified. It is shown that, if the recursive check is omitted, it is possible to miss the identification of some dead-ending rotameric states causing a premature termination of the elimination process. Second, we examined the effects of removing dead-ending rotameric states from further considerations at different moments of time. Two different methods of rotameric state removal were examined for an order dependence. In one case, each rotamer found to be incompatible with the global minimum energy conformation was removed immediately following its identification. In the other, dead-ending rotamers were marked for deletion but retained during the search, so that they influenced the evaluation of other rotameric states. When the search was completed, all marked rotamers were removed simultaneously. In addition, to expand further the usefulness of the FEE, a novel method is presented that allows for further reduction in the remaining set of conformations at the FEE convergence. In this method, called a tree-based search, each dead-ending pair of rotamers which does not lead to the direct removal of either rotameric state is used to reduce significantly the number of remaining conformations. In the future this method can also be expanded to triplet and quadruplet sets of rotameric states. We tested our implementation of the FEE by exhaustively searching ten protein segments and found that the FEE identified the global minimum every time. For each segment, the global minimum was exhaustively searched in two different environments: (i) the segments were extracted from the protein and exhaustively searched in the absence of the surrounding residues; (ii) the segments were exhaustively searched in the presence of the remaining residues fixed at crystal structure conformations. We also evaluated the performance of the method for accurately predicting side chain conformations. We examined the influence of factors such as type and accuracy of backbone template used, and the restrictions imposed by the choice of potential function, parameterization and rotamer database. Conclusions are drawn on these results and future prospects are given.

Growth responses of mature loblolly pine to dead wood.manipulations.

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

Ulyshen, Michael D.; Horn, Scott; Hanula, James L.

Large-scale manipulations of dead wood in mature Pinus taeda L. stands in the southeastern United States included a major one-time input of logs (fivefold increase in log volume) created by felling trees onsite, annual removals of all dead wood above >10 cm in diameter and >60 cm in length, and a reference in which no manipulations took place. We returned over a decade later to determine how these treatments affected tree growth using increment cores. There were no significant differences in tree density, basal area or tree diameters among treatments at the time of sampling. Although tree growth was consistentlymore » higher in the log-input plots and lower in the removal plots, this was true even during the 5 year period before the experiment began. When growth data from this initial period were included in the model as a covariate, no differences in post-treatment tree growth were detected. It is possible that treatment effects will become apparent after more time has passed, however.« less

24 CFR 3280.401 - Structural load tests.

Code of Federal Regulations, 2013 CFR

2013-04-01

... sustaining its dead load plus superimposed live loads equal to 1.75 times the required live loads for a... in 1/4 design live load increments at 10-minute intervals until 1.25 times design live load plus dead... load plus dead load has been reached. Assembly failure shall be considered as design live load...

76 FR 63341 - Culturally Significant Objects Imported for Exhibition Determinations: “The Dead Sea Scrolls...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-12

... DEPARTMENT OF STATE [Public Notice 7644] Culturally Significant Objects Imported for Exhibition Determinations: ``The Dead Sea Scrolls: Life and Faith in Biblical Times'' SUMMARY: Notice is hereby given of the... exhibition ``The Dead Sea Scrolls: Life and Faith in Biblical Times'' imported from abroad for temporary...

24 CFR 3280.401 - Structural load tests.

Code of Federal Regulations, 2010 CFR

2010-04-01

... sustaining its dead load plus superimposed live loads equal to 1.75 times the required live loads for a... in 1/4 design live load increments at 10-minute intervals until 1.25 times design live load plus dead... load plus dead load has been reached. Assembly failure shall be considered as design live load...

24 CFR 3280.401 - Structural load tests.

Code of Federal Regulations, 2014 CFR

2014-04-01

... sustaining its dead load plus superimposed live loads equal to 1.75 times the required live loads for a... in 1/4 design live load increments at 10-minute intervals until 1.25 times design live load plus dead... load plus dead load has been reached. Assembly failure shall be considered as design live load...

24 CFR 3280.401 - Structural load tests.

Code of Federal Regulations, 2012 CFR

2012-04-01

... sustaining its dead load plus superimposed live loads equal to 1.75 times the required live loads for a... in 1/4 design live load increments at 10-minute intervals until 1.25 times design live load plus dead... load plus dead load has been reached. Assembly failure shall be considered as design live load...

24 CFR 3280.401 - Structural load tests.

Code of Federal Regulations, 2011 CFR

2011-04-01

... sustaining its dead load plus superimposed live loads equal to 1.75 times the required live loads for a... in 1/4 design live load increments at 10-minute intervals until 1.25 times design live load plus dead... load plus dead load has been reached. Assembly failure shall be considered as design live load...

Delay time correction of the gas analyzer in the calculation of anatomical dead space of the lung.

PubMed

Okubo, T; Shibata, H; Takishima, T

1983-07-01

By means of a mathematical model, we have studied a way to correct the delay time of the gas analyzer in order to calculate the anatomical dead space using Fowler's graphical method. The mathematical model was constructed of ten tubes of equal diameter but unequal length, so that the amount of dead space varied from tube to tube; the tubes were emptied sequentially. The gas analyzer responds with a time lag from the input of the gas signal to the beginning of the response, followed by an exponential response output. The single breath expired volume-concentration relationship was examined with three types of expired flow patterns of which were constant, exponential and sinusoidal. The results indicate that the time correction by the lag time plus time constant of the exponential response of the gas analyzer gives an accurate estimation of anatomical dead space. Time correction less inclusive than this, e.g. lag time only or lag time plus 50% response time, gives an overestimation, and a correction larger than this results in underestimation. The magnitude of error is dependent on the flow pattern and flow rate. The time correction in this study is only for the calculation of dead space, as the corrected volume-concentration curves does not coincide with the true curve. Such correction of the output of the gas analyzer is extremely important when one needs to compare the dead spaces of different gas species at a rather faster flow rate.

The Feynman-Y Statistic in Relation to Shift-Register Neutron Coincidence Counting: Precision and Dead Time

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

Croft, Stephen; Santi, Peter A.; Henzlova, Daniela

The Feynman-Y statistic is a type of autocorrelation analysis. It is defined as the excess variance-to-mean ratio, Y = VMR - 1, of the number count distribution formed by sampling a pulse train using a series of non-overlapping gates. It is a measure of the degree of correlation present on the pulse train with Y = 0 for Poisson data. In the context of neutron coincidence counting we show that the same information can be obtained from the accidentals histogram acquired using the multiplicity shift-register method, which is currently the common autocorrelation technique applied in nuclear safeguards. In the casemore » of multiplicity shift register analysis however, overlapping gates, either triggered by the incoming pulse stream or by a periodic clock, are used. The overlap introduces additional covariance but does not alter the expectation values. In this paper we discuss, for a particular data set, the relative merit of the Feynman and shift-register methods in terms of both precision and dead time correction. Traditionally the Feynman approach is applied with a relatively long gate width compared to the dieaway time. The main reason for this is so that the gate utilization factor can be taken as unity rather than being treated as a system parameter to be determined at characterization/calibration. But because the random trigger interval gate utilization factor is slow to saturate this procedure requires a gate width many times the effective 1/e dieaway time. In the traditional approach this limits the number of gates that can be fitted into a given assay duration. We empirically show that much shorter gates, similar in width to those used in traditional shift register analysis can be used. Because the way in which the correlated information present on the pulse train is extracted is different for the moments based method of Feynman and the various shift register based approaches, the dead time losses are manifested differently for these two approaches. The resulting estimates for the dead time corrected first and second order reduced factorial moments should be independent of the method however and this allows the respective dead time formalism to be checked. We discuss how to make dead time corrections in both the shift register and the Feynman approaches.« less

Effects on birds of fenthion aerial application for mosquito control

USGS Publications Warehouse

DeWeese, L.R.; McEwen, L.C.; Settimi, L.A.; Deblinger, R.D.

1983-01-01

Effects on birds of an aerial application of fenthion, a potent organophosphorus cholinesterase (ChE)-inhibiting insecticide, were assessed on four study sites 1.8 to 3.6 km2 in size. These sites were located within 121.5 km2 of wet meadows treated with 47 g of fenthion (AI) per ha in ultralow- volume formulation. Assessment methods were searches for sick or dead birds, measurements of brain ChE activity in specimens found dead or collected alive at different time intervals, and counts of bird populations. After treatment, 99 birds and 15 mammals were found sick or dead; 106 of these were on one site. Brain ChE activity in dead birds was depressed sufficiently to indicate that death was caused by an anti-ChE substance. Brain ChE activity in three common bird species collected alive showed the greatest reduction 2 days postspray. Two of these species had ChE activity that was still significantly (P<0.05) depressed 15 days postspray. Bird populations declined most where mortality was heaviest. Fenthion sprayed for mosquito control was life threatening to many birds inhabiting treated meadows.

Examining the Impact of External Influences on Police Use of Deadly Force over Time.

ERIC Educational Resources Information Center

White, Michael D.

2002-01-01

Used interrupted time-series analysis (ARIMA) to study the impact of legislation and judicial intervention on the use of deadly force by police officers in Philadelphia, Pennsylvania. Findings generally suggest that dynamic changes in the internal working environment can outweigh the influence of external mechanisms on deadly force use. Findings…

Model-Based Dead Time Optimization for Voltage-Source Converters Utilizing Silicon Carbide Semiconductors

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

Zhang, Zheyu; Lu, Haifeng; Costinett, Daniel J.

Dead time significantly affects the reliability, power quality, and efficiency of voltage-source converters. For silicon carbide (SiC) devices, considering the high sensitivity of turn-off time to the operating conditions (> 5× difference between light load and full load) and characteristics of inductive loads (> 2× difference between motor load and inductor), as well as large additional energy loss induced by the freewheeling diode conduction during the superfluous dead time (~15% of the switching loss), then the traditional fixed dead time setting becomes inappropriate. This paper introduces an approach to adaptively regulate the dead time considering the current operating condition andmore » load characteristics via synthesizing online monitored turn-off switching parameters in the microcontroller with an embedded preset optimization model. Here, based on a buck converter built with 1200-V SiC MOSFETs, the experimental results show that the proposed method is able to ensure reliability and reduce power loss by 12% at full load and 18.2% at light load (8% of the full load in this case study).« less

Model-Based Dead Time Optimization for Voltage-Source Converters Utilizing Silicon Carbide Semiconductors

DOE PAGES

Zhang, Zheyu; Lu, Haifeng; Costinett, Daniel J.; ...

2016-12-29

Dead time significantly affects the reliability, power quality, and efficiency of voltage-source converters. For silicon carbide (SiC) devices, considering the high sensitivity of turn-off time to the operating conditions (> 5× difference between light load and full load) and characteristics of inductive loads (> 2× difference between motor load and inductor), as well as large additional energy loss induced by the freewheeling diode conduction during the superfluous dead time (~15% of the switching loss), then the traditional fixed dead time setting becomes inappropriate. This paper introduces an approach to adaptively regulate the dead time considering the current operating condition andmore » load characteristics via synthesizing online monitored turn-off switching parameters in the microcontroller with an embedded preset optimization model. Here, based on a buck converter built with 1200-V SiC MOSFETs, the experimental results show that the proposed method is able to ensure reliability and reduce power loss by 12% at full load and 18.2% at light load (8% of the full load in this case study).« less

Cell tracking using iron oxide fails to distinguish dead from living transplanted cells in the infarcted heart.

PubMed

Winter, E M; Hogers, B; van der Graaf, L M; Gittenberger-de Groot, A C; Poelmann, R E; van der Weerd, L

2010-03-01

Recently, debate has arisen about the usefulness of cell tracking using iron oxide-labeled cells. Two important issues in determining the usefulness of cell tracking with MRI are generally overlooked; first, the effect of graft rejection in immunocompetent models, and second, the necessity for careful histological confirmation of the fate of the labeled cells in the presence of iron oxide. Therefore, both iron oxide-labeled living as well as dead epicardium-derived cells (EPDCs) were investigated in ischemic myocardium of immunodeficient non-obese diabetic (NOD)/acid: non-obese diabetic severe combined immunodeficient (NOD/scid) mice with 9.4T MRI until 6 weeks after surgery, at which time immunohistochemical analysis was performed. In both groups, voids on MRI scans were observed that did not change in number, size, or localization over time. Based on MRI, no distinction could be made between living and dead injected cells. Prussian blue staining confirmed that the hypointense spots on MRI corresponded to iron-loaded cells. However, in the dead-EPDC recipients, all iron-positive cells appeared to be macrophages, while the living-EPDC recipients also contained engrafted iron-loaded EPDCs. Iron labeling is inadequate for determining the fate of transplanted cells in the immunodeficient host, since dead cells produce an MRI signal indistinguishable from incorporated living cells. (c) 2010 Wiley-Liss, Inc.

Coding for Communication Channels with Dead-Time Constraints

NASA Technical Reports Server (NTRS)

Moision, Bruce; Hamkins, Jon

2004-01-01

Coding schemes have been designed and investigated specifically for optical and electronic data-communication channels in which information is conveyed via pulse-position modulation (PPM) subject to dead-time constraints. These schemes involve the use of error-correcting codes concatenated with codes denoted constrained codes. These codes are decoded using an interactive method. In pulse-position modulation, time is partitioned into frames of Mslots of equal duration. Each frame contains one pulsed slot (all others are non-pulsed). For a given channel, the dead-time constraints are defined as a maximum and a minimum on the allowable time between pulses. For example, if a Q-switched laser is used to transmit the pulses, then the minimum allowable dead time is the time needed to recharge the laser for the next pulse. In the case of bits recorded on a magnetic medium, the minimum allowable time between pulses depends on the recording/playback speed and the minimum distance between pulses needed to prevent interference between adjacent bits during readout. The maximum allowable dead time for a given channel is the maximum time for which it is possible to satisfy the requirement to synchronize slots. In mathematical shorthand, the dead-time constraints for a given channel are represented by the pair of integers (d,k), where d is the minimum allowable number of zeroes between ones and k is the maximum allowable number of zeroes between ones. A system of the type to which the present schemes apply is represented by a binary- input, real-valued-output channel model illustrated in the figure. At the transmitting end, information bits are first encoded by use of an error-correcting code, then further encoded by use of a constrained code. Several constrained codes for channels subject to constraints of (d,infinity) have been investigated theoretically and computationally. The baseline codes chosen for purposes of comparison were simple PPM codes characterized by M-slot PPM frames separated by d-slot dead times.

Dead-time Corrected Disdrometer Data

DOE Data Explorer

Bartholomew, Mary Jane

2008-03-05

Original and dead-time corrected disdrometer results for observations made at SGP and TWP. The correction is based on the technique discussed in Sheppard and Joe, 1994. In addition, these files contain calculated radar reflectivity factor, mean Doppler velocity and attenuation for every measurement for both the original and dead-time corrected data at the following wavelengths: 0.316, 0.856, 3.2, 5, and 10cm (W,K,X,C,S bands). Pavlos Kollias provided the code to do these calculations.

Gigahertz-gated InGaAs/InP single-photon detector with detection efficiency exceeding 55% at 1550 nm

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

Comandar, L. C.; Engineering Department, Cambridge University, 9 J J Thomson Ave, Cambridge CB3 0FA; Fröhlich, B.

We report on a gated single-photon detector based on InGaAs/InP avalanche photodiodes (APDs) with a single-photon detection efficiency exceeding 55% at 1550 nm. Our detector is gated at 1 GHz and employs the self-differencing technique for gate transient suppression. It can operate nearly dead time free, except for the one clock cycle dead time intrinsic to self-differencing, and we demonstrate a count rate of 500 Mcps. We present a careful analysis of the optimal driving conditions of the APD measured with a dead time free detector characterization setup. It is found that a shortened gate width of 360 ps together with anmore » increased driving signal amplitude and operation at higher temperatures leads to improved performance of the detector. We achieve an afterpulse probability of 7% at 50% detection efficiency with dead time free measurement and a record efficiency for InGaAs/InP APDs of 55% at an afterpulse probability of only 10.2% with a moderate dead time of 10 ns.« less

Moessbauer spectrometer based on UNO-4096-90 accumulator and Elektronika D3-28 microcomputer for simultaneous recording of four spectra

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

Romanov, E.S.; Ivoilov, N.G.

A buffer memory unit and an interface for the UNO-4096-90 accumulator with an Elektronika D3-28 microcomputer are described that allow simultaneous recording of four Moessbauer spectra with zero dead time. For complete elimination of dead time, the pulses from each detector are fed to two buffer counters units, which operate alternately in the write and interrogate modes. This organization of the buffer memory also completely eliminates the effect of the sensors on one another. The use of these circuits does not require any modifications of the computer or accumulator.

Signal to noise ratio of energy selective x-ray photon counting systems with pileup.

PubMed

Alvarez, Robert E

2014-11-01

To derive fundamental limits on the effect of pulse pileup and quantum noise in photon counting detectors on the signal to noise ratio (SNR) and noise variance of energy selective x-ray imaging systems. An idealized model of the response of counting detectors to pulse pileup is used. The model assumes a nonparalyzable response and delta function pulse shape. The model is used to derive analytical formulas for the noise and energy spectrum of the recorded photons with pulse pileup. These formulas are first verified with a Monte Carlo simulation. They are then used with a method introduced in a previous paper [R. E. Alvarez, "Near optimal energy selective x-ray imaging system performance with simple detectors," Med. Phys. 37, 822-841 (2010)] to compare the signal to noise ratio with pileup to the ideal SNR with perfect energy resolution. Detectors studied include photon counting detectors with pulse height analysis (PHA), detectors that simultaneously measure the number of photons and the integrated energy (NQ detector), and conventional energy integrating and photon counting detectors. The increase in the A-vector variance with dead time is also computed and compared to the Monte Carlo results. A formula for the covariance of the NQ detector is developed. The validity of the constant covariance approximation to the Cramèr-Rao lower bound (CRLB) for larger counts is tested. The SNR becomes smaller than the conventional energy integrating detector (Q) SNR for 0.52, 0.65, and 0.78 expected number photons per dead time for counting (N), two, and four bin PHA detectors, respectively. The NQ detector SNR is always larger than the N and Q SNR but only marginally so for larger dead times. Its noise variance increases by a factor of approximately 3 and 5 for the A1 and A2 components as the dead time parameter increases from 0 to 0.8 photons per dead time. With four bin PHA data, the increase in variance is approximately 2 and 4 times. The constant covariance approximation to the CRLB is valid for larger counts such as those used in medical imaging. The SNR decreases rapidly as dead time increases. This decrease places stringent limits on allowable dead times with the high count rates required for medical imaging systems. The probability distribution of the idealized data with pileup is shown to be accurately described as a multivariate normal for expected counts greater than those typically utilized in medical imaging systems. The constant covariance approximation to the CRLB is also shown to be valid in this case. A new formula for the covariance of the NQ detector with pileup is derived and validated.

Signal to noise ratio of energy selective x-ray photon counting systems with pileup

PubMed Central

Alvarez, Robert E.

2014-01-01

Purpose: To derive fundamental limits on the effect of pulse pileup and quantum noise in photon counting detectors on the signal to noise ratio (SNR) and noise variance of energy selective x-ray imaging systems. Methods: An idealized model of the response of counting detectors to pulse pileup is used. The model assumes a nonparalyzable response and delta function pulse shape. The model is used to derive analytical formulas for the noise and energy spectrum of the recorded photons with pulse pileup. These formulas are first verified with a Monte Carlo simulation. They are then used with a method introduced in a previous paper [R. E. Alvarez, “Near optimal energy selective x-ray imaging system performance with simple detectors,” Med. Phys. 37, 822–841 (2010)] to compare the signal to noise ratio with pileup to the ideal SNR with perfect energy resolution. Detectors studied include photon counting detectors with pulse height analysis (PHA), detectors that simultaneously measure the number of photons and the integrated energy (NQ detector), and conventional energy integrating and photon counting detectors. The increase in the A-vector variance with dead time is also computed and compared to the Monte Carlo results. A formula for the covariance of the NQ detector is developed. The validity of the constant covariance approximation to the Cramèr–Rao lower bound (CRLB) for larger counts is tested. Results: The SNR becomes smaller than the conventional energy integrating detector (Q) SNR for 0.52, 0.65, and 0.78 expected number photons per dead time for counting (N), two, and four bin PHA detectors, respectively. The NQ detector SNR is always larger than the N and Q SNR but only marginally so for larger dead times. Its noise variance increases by a factor of approximately 3 and 5 for the A1 and A2 components as the dead time parameter increases from 0 to 0.8 photons per dead time. With four bin PHA data, the increase in variance is approximately 2 and 4 times. The constant covariance approximation to the CRLB is valid for larger counts such as those used in medical imaging. Conclusions: The SNR decreases rapidly as dead time increases. This decrease places stringent limits on allowable dead times with the high count rates required for medical imaging systems. The probability distribution of the idealized data with pileup is shown to be accurately described as a multivariate normal for expected counts greater than those typically utilized in medical imaging systems. The constant covariance approximation to the CRLB is also shown to be valid in this case. A new formula for the covariance of the NQ detector with pileup is derived and validated. PMID:25370642

Stabilization and analytical tuning rule of double-loop control scheme for unstable dead-time process

NASA Astrophysics Data System (ADS)

Ugon, B.; Nandong, J.; Zang, Z.

2017-06-01

The presence of unstable dead-time systems in process plants often leads to a daunting challenge in the design of standard PID controllers, which are not only intended to provide close-loop stability but also to give good performance-robustness overall. In this paper, we conduct stability analysis on a double-loop control scheme based on the Routh-Hurwitz stability criteria. We propose to use this unstable double-loop control scheme which employs two P/PID controllers to control first-order or second-order unstable dead-time processes typically found in process industries. Based on the Routh-Hurwitz stability necessary and sufficient criteria, we establish several stability regions which enclose within them the P/PID parameter values that guarantee close-loop stability of the double-loop control scheme. A systematic tuning rule is developed for the purpose of obtaining the optimal P/PID parameter values within the established regions. The effectiveness of the proposed tuning rule is demonstrated using several numerical examples and the result are compared with some well-established tuning methods reported in the literature.

Statistical Parameter Study of the Time Interval Distribution for Nonparalyzable, Paralyzable, and Hybrid Dead Time Models

NASA Astrophysics Data System (ADS)

Syam, Nur Syamsi; Maeng, Seongjin; Kim, Myo Gwang; Lim, Soo Yeon; Lee, Sang Hoon

2018-05-01

A large dead time of a Geiger Mueller (GM) detector may cause a large count loss in radiation measurements and consequently may cause distortion of the Poisson statistic of radiation events into a new distribution. The new distribution will have different statistical parameters compared to the original distribution. Therefore, the variance, skewness, and excess kurtosis in association with the observed count rate of the time interval distribution for well-known nonparalyzable, paralyzable, and nonparalyzable-paralyzable hybrid dead time models of a Geiger Mueller detector were studied using Monte Carlo simulation (GMSIM). These parameters were then compared with the statistical parameters of a perfect detector to observe the change in the distribution. The results show that the behaviors of the statistical parameters for the three dead time models were different. The values of the skewness and the excess kurtosis of the nonparalyzable model are equal or very close to those of the perfect detector, which are ≅2 for skewness, and ≅6 for excess kurtosis, while the statistical parameters in the paralyzable and hybrid model obtain minimum values that occur around the maximum observed count rates. The different trends of the three models resulting from the GMSIM simulation can be used to distinguish the dead time behavior of a GM counter; i.e. whether the GM counter can be described best by using the nonparalyzable, paralyzable, or hybrid model. In a future study, these statistical parameters need to be analyzed further to determine the possibility of using them to determine a dead time for each model, particularly for paralyzable and hybrid models.

Quantifying surface water runoff from Wadi Arogut towards the Dead Sea

NASA Astrophysics Data System (ADS)

Geyer, Stefan; Khayat, Saed; Marei, Amer

2015-04-01

The surrounded area of the Dead Sea, especially the west side suffers from many hydrological problems. While the Dead Sea level drop considered a major problem that affect the quality of the surrounded freshwater resources, a lot of the surface water flood from the adjacent Wadi are lost through direct run off without any exploitation. Therefore, it is necessary to maintain a type of balance between surface water exploitation through the Wadi and at the same time allow a sufficient amount of flow to the Dead Sea to ensure its sustainability. In this study, we choose one of the larger tributaries in the western side of the Dead Sea basin. The stream was modelled for runoff response to different rainfall amount and climate conditions (dry, normal, and wet seasons) which were chosen from the rainy seasons in the previous 30 years. Finally, the amount of surface water contribution from each of the three seasons of the Dead Sea was quantified. The outcome of the model shows the results from the normal rainy season, which is frequently reoccurs and common in the region. The model data show that such events normally contribute with about 18-22 MCM annually to the Dead Sea. The problem is with the recurrence of dry season such as 2005/2006, by which the amount of the surface water decrease and consequently has adverse effect on the Dead Sea. However, the presence of less frequent thunder storm season such as that one in 1991/1992 has also a positive effect on the Dead Sea level. In the rainy season 1991/1992 there was a higher amount of rainfall over the study area that reaches around 155 MCM. Despite the presence of this high amount most of the recharge lost to the ground as groundwater recharge. The high amount of rain increases the amount of inundated surface water out of the Wadi banks and covers more surfaces all over the study area, which in role promote more water loss to the ground. That is why the total loss (rather than surface runoff) was much higher (77%). Moreover, 50% less precipitation in 2006 decrease the Dead Sea five metres within five years, and 60% 1992 increase of precipitation raise the water level two metre only for two to three next years. How can we balance the groundwater needs and the Dead Sea survival with those 40% surface water? By no mean: preventing the Dead Sea decline by increasing runoff will not only preventing the fresh water deterioration, but also it will be in the account of groundwater recharge in the surrounding aquifers of the Dead Sea. These conclusions suggest strongly the need of an integrated groundwater model, in order to quantify all scenarios.

75 FR 34064 - Manufactured Home Construction and Safety Standards, Test Procedures for Roof Trusses

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-16

... dead load, or to 1.75 times the uplift load, minus the dead load in the upright position. [See Figure... 1/32-inch. Dead load must be applied to the top and bottom chord, and live load must be applied to... procedure. (i) Dead load. Measure and record initial elevation of the truss or trusses in the test position...

More Dead than Dead: Perceptions of Persons in the Persistent Vegetative State

ERIC Educational Resources Information Center

Gray, Kurt; Knickman, T. Anne; Wegner, Daniel M.

2011-01-01

Patients in persistent vegetative state (PVS) may be biologically alive, but these experiments indicate that people see PVS as a state curiously more dead than dead. Experiment 1 found that PVS patients were perceived to have less mental capacity than the dead. Experiment 2 explained this effect as an outgrowth of afterlife beliefs, and the…

Cost-Effectiveness Analysis of a Mobile Ear Screening and Surveillance Service versus an Outreach Screening, Surveillance and Surgical Service for Indigenous Children in Australia

PubMed Central

Nguyen, Kim-Huong; Smith, Anthony C.; Armfield, Nigel R.; Bensink, Mark; Scuffham, Paul A.

2015-01-01

Indigenous Australians experience a high rate of ear disease and hearing loss, yet they have a lower rate of service access and utilisation compared to their non-Indigenous counterparts. Screening, surveillance and timely access to specialist ear, nose and throat (ENT) services are key components in detecting and preventing the recurrence of ear diseases. To address the low access and utilisation rate by Indigenous Australians, a collaborative, community-based mobile telemedicine-enabled screening and surveillance (MTESS) service was trialled in Cherbourg, the third largest Indigenous community in Queensland, Australia. This paper aims to evaluate the cost-effectiveness of the MTESS service using a lifetime Markov model that compares two options: (i) the Deadly Ears Program alone (current practice involving an outreach ENT surgical service and screening program), and (ii) the Deadly Ears Program supplemented with the MTESS service. Data were obtained from the Deadly Ears Program, a feasibility study of the MTESS service and the literature. Incremental cost-utility ratios were calculated from a societal perspective with both costs (in 2013–14 Australian dollars) and quality-adjusted life years (QALYs) discounted at 5% annually. The model showed that compared with the Deadly Ears Program, the probability of an acceptable cost-utility ratio at a willingness-to-pay threshold of $50,000/QALY was 98% for the MTESS service. This cost effectiveness arises from preventing hearing loss in the Indigenous population and the subsequent reduction in associated costs. Deterministic and probability sensitivity analyses indicated that the model was robust to parameter changes. We concluded that the MTESS service is a cost-effective strategy. It presents an opportunity to resolve major issues confronting Australia’s health system such as the inequitable provision and access to quality healthcare for rural and remotes communities, and for Indigenous Australians. Additionally, it may encourage effective health service delivery at a time when the healthcare funding and workforce capacity are limited. PMID:26406592

Cost-Effectiveness Analysis of a Mobile Ear Screening and Surveillance Service versus an Outreach Screening, Surveillance and Surgical Service for Indigenous Children in Australia.

PubMed

Nguyen, Kim-Huong; Smith, Anthony C; Armfield, Nigel R; Bensink, Mark; Scuffham, Paul A

2015-01-01

Indigenous Australians experience a high rate of ear disease and hearing loss, yet they have a lower rate of service access and utilisation compared to their non-Indigenous counterparts. Screening, surveillance and timely access to specialist ear, nose and throat (ENT) services are key components in detecting and preventing the recurrence of ear diseases. To address the low access and utilisation rate by Indigenous Australians, a collaborative, community-based mobile telemedicine-enabled screening and surveillance (MTESS) service was trialled in Cherbourg, the third largest Indigenous community in Queensland, Australia. This paper aims to evaluate the cost-effectiveness of the MTESS service using a lifetime Markov model that compares two options: (i) the Deadly Ears Program alone (current practice involving an outreach ENT surgical service and screening program), and (ii) the Deadly Ears Program supplemented with the MTESS service. Data were obtained from the Deadly Ears Program, a feasibility study of the MTESS service and the literature. Incremental cost-utility ratios were calculated from a societal perspective with both costs (in 2013-14 Australian dollars) and quality-adjusted life years (QALYs) discounted at 5% annually. The model showed that compared with the Deadly Ears Program, the probability of an acceptable cost-utility ratio at a willingness-to-pay threshold of $50,000/QALY was 98% for the MTESS service. This cost effectiveness arises from preventing hearing loss in the Indigenous population and the subsequent reduction in associated costs. Deterministic and probability sensitivity analyses indicated that the model was robust to parameter changes. We concluded that the MTESS service is a cost-effective strategy. It presents an opportunity to resolve major issues confronting Australia's health system such as the inequitable provision and access to quality healthcare for rural and remotes communities, and for Indigenous Australians. Additionally, it may encourage effective health service delivery at a time when the healthcare funding and workforce capacity are limited.

Studies of ZVS soft switching of dual-active-bridge isolated bidirectional DC-DC converters

NASA Astrophysics Data System (ADS)

Xu, Fei; Zhao, Feng; Shi, Qibiao; Wen, Xuhui

2018-05-01

To operate dual-active-bridge isolated bidirectional dc- dc converter (DAB) at high efficiency, the two bridge switches must operate with Zero-Voltage-Switching (ZVS) over as wide an operating range as possible. This paper proposes a new perspective on realizing ZVS in dead-time. An exact theoretical analysis and mathematical mode is built to explain the process of ZVS switching in dead-time under Single Phase Shift (SPS) control strategy. In order to assure the two bridge switches operate on soft switching, every SPS switching point is analyzed. Generally, dead-time will be determined when the power electronic devices is selected. The key factor to realizing ZVS is the size of the end time of resonance comparing to dead-time. Through detailed analysis, it can obtain the conditions of all switches achieving ZVS turn-on and turn-off. Finally, simulation validates the theoretical analysis and some advice are given to realize the ZVS soft switching.

Relative biological effectiveness of fast neutrons compared with X-rays: Prenatal mortality in the mouse

NASA Technical Reports Server (NTRS)

Friedberg, W.; Hanneman, G. D.; Faulkner, D. N.; Darden, E. B., Jr.

1972-01-01

The effects of fission neutrons and of X-rays on the mouse zygote are discussed. Seven-week-old virgin mice were allowed a 12-hour mating opportunity beginning at 7:00 P.M. Between 1:30 and 4:00 P.M., except where indicated otherwise, the females which had mated (vaginal plug) during the night were either irradiated or sham-irradiated. At the time of irradiation the zygotes were in a pronuclear stage. Sixteen days later the mice were killed and the uteri dissected. The number of dead embryos, live embryos, and gross anomalies were determined. Dead embryos were classified as to stage of development.

The Role of Dead Wood in Maintaining Arthropod Diversity on the Forest Floor

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

Hanula, James L.; Horn, Scott; Wade, Dale D.

2006-08-01

Dead wood is a major component of forests and contributes to overall diversity, primarily by supporting insects that feed directly on or in it. Further, a variety of organisms benefit by feeding on those insects. What is not well known is how or whether dead wood influences the composition of the arthropod community that is not solely dependent on it as a food resource, or whether woody debris influences prey available to generalist predators. One group likely to be affected by dead wood is ground-dwelling arthropods. We studied the effect of adding large dead wood to unburned and frequently burnedmore » pine stands to determine if dead wood was used more when the litter and understory plant community are removed. We also studied the effect of annual removal of dead wood from large (10-ha) plots over a 5-year period on ground-dwelling arthropods. In related studies, we examined the relationships among an endangered woodpecker that forages for prey on live trees, its prey, and dead wood in the forest. Finally, the results of these and other studies show that dead wood can influence the abundance and diversity of the ground-dwelling arthropod community and of prey available to generalist predators not foraging directly on dead trees.« less

More dead than dead: perceptions of persons in the persistent vegetative state.

PubMed

Gray, Kurt; Knickman, T Anne; Wegner, Daniel M

2011-11-01

Patients in persistent vegetative state (PVS) may be biologically alive, but these experiments indicate that people see PVS as a state curiously more dead than dead. Experiment 1 found that PVS patients were perceived to have less mental capacity than the dead. Experiment 2 explained this effect as an outgrowth of afterlife beliefs, and the tendency to focus on the bodies of PVS patients at the expense of their minds. Experiment 3 found that PVS is also perceived as "worse" than death: people deem early death better than being in PVS. These studies suggest that people perceive the minds of PVS patients as less valuable than those of the dead - ironically, this effect is especially robust for those high in religiosity. Copyright © 2011 Elsevier B.V. All rights reserved.

Lessons to be learned: a case study approach. Unseasonal severe poisoning of two adults by deadly nightside (Atropa belladonna).

PubMed

Southgate, H J; Egerton, M; Dauncey, E A

2000-06-01

Unseasonal, mid-winter, severe poisoning by deadly nightshade is reported in two adults who simultaneously ate from a pie made of frozen deadly nightshade berries, mistaken at the time of picking for bilberries. Atropine levels are reported in the urine. Physostigmine treatment was ineffective.

Effects of Variations in Forebody and Afterbody Dead Rise on the Resistance and Spray Characteristics of the 22ADR Class VPB Airplane: Langley Tank Model 207, TED No. NACA 2361

NASA Technical Reports Server (NTRS)

Clement, Eugene P.; Daniels, Charles J.

1947-01-01

An investigation was made to determine the effects of changes in the amount and distribution of forebody and afterbody dead rise on the hydrodynamic resistance and spray characteristics of a 1/11-size model of the Bureau of Aeronautics design No. 22ADR class VPB airplane. The variations in dead rise within the range investigated had no significant effects on resistance or trim, free to trim, or on resistance or trimming moment, fixed in trim. The coordinates of the peaks of the bow-spray blisters, with reference to the model, were measured at low speeds, and it was found that the model with the low dead rise at the bow had the lowest blisters. The changes in position of the maximum dead rise of the afterbody had no effect on the bow-spray blister.

Anti-Apoptotic Effects of 3,3',5-Triiodo-L-Thyronine in the Liver of Brain-Dead Rats.

PubMed

Rebolledo, Rolando A; Van Erp, Anne C; Ottens, Petra J; Wiersema-Buist, Janneke; Leuvenink, Henri G D; Romanque, Pamela

2015-01-01

Thyroid hormone treatment in brain-dead organ donors has been extensively studied and applied in the clinical setting. However, its clinical applicability remains controversial due to a varying degree of success and a lack of mechanistic understanding about the therapeutic effects of 3,3',5-Triiodo-L-thyronine (T3). T3 pre-conditioning leads to anti-apoptotic and pro-mitotic effects in liver tissue following ischemia/reperfusion injury. Therefore, we aimed to study the effects of T3 pre-conditioning in the liver of brain-dead rats. Brain death (BD) was induced in mechanically ventilated rats by inflation of a Fogarty catheter in the epidural space. T3 (0.1 mg/kg) or vehicle was administered intraperitoneally 2 h prior to BD induction. After 4 h of BD, serum and liver tissue were collected. RT-qPCR, routine biochemistry, and immunohistochemistry were performed. Brain-dead animals treated with T3 had lower plasma levels of AST and ALT, reduced Bax gene expression, and less hepatic cleaved Caspase-3 activation compared to brain-dead animals treated with vehicle. Interestingly, no differences in the expression of inflammatory genes (IL-6, MCP-1, IL-1β) or the presence of pro-mitotic markers (Cyclin-D and Ki-67) were found in brain-dead animals treated with T3 compared to vehicle-treated animals. T3 pre-conditioning leads to beneficial effects in the liver of brain-dead rats as seen by lower cellular injury and reduced apoptosis, and supports the suggested role of T3 hormone therapy in the management of brain-dead donors.

Indirect measurement of three-photon correlation in nonclassical light sources

NASA Astrophysics Data System (ADS)

Ann, Byoung-moo; Song, Younghoon; Kim, Junki; Yang, Daeho; An, Kyungwon

2016-06-01

We observe the three-photon correlation in nonclassical light sources by using an indirect measurement scheme based on the dead-time effect of photon-counting detectors. We first develop a general theory which enables us to extract the three-photon correlation from the two-photon correlation of an arbitrary light source measured with detectors with finite dead times. We then confirm the validity of our measurement scheme in experiments done with a cavity-QED microlaser operating with a large intracavity mean photon number exhibiting both sub- and super-Poissonian photon statistics. The experimental results are in good agreement with the theoretical expectation. Our measurement scheme provides an alternative approach for N -photon correlation measurement employing (N -1 ) detectors and thus a reduced measurement time for a given signal-to-noise ratio, compared to the usual scheme requiring N detectors.

Global effects of the DEAD-box RNA helicase DeaD (CsdA) on gene expression over a broad range of temperatures

PubMed Central

Vakulskas, Christopher A.; Pannuri, Archana; Cortés-Selva, Diana; Zere, Tesfalem R.; Ahmer, Brian M.; Babitzke, Paul; Romeo, Tony

2014-01-01

Summary In Escherichia coli, activity of the global regulatory RNA binding protein CsrA is antagonized by two noncoding sRNAs, CsrB and CsrC, which sequester it away from its lower affinity mRNA targets. Transcription of csrB/C requires the BarA-UvrY two component signal transduction system, which responds to short chain carboxylates. We show that two DEAD-box RNA helicases, DeaD and SrmB, activate csrB/C expression by different pathways. DeaD facilitates uvrY translation by counteracting the inhibitory effect of long distance basepairing between the uvrY mRNA leader and coding region, while SrmB does not affect UvrY or UvrY-phosphate levels. Contrary to the prevailing notion that these helicases act primarily at low temperatures, DeaD and SrmB activated csrB expression over a wide temperature range. High-throughput sequencing of RNA isolated by crosslinking immunoprecipitation (HITS-CLIP) revealed in vivo interactions of DeaD with 39 mRNAs, including those of uvrY and 9 other regulatory genes. Studies on the expression of several of the identified genes revealed regulatory effects of DeaD in all cases and diverse temperature response patterns. Our findings uncover an expanded regulatory role for DeaD, which is mediated through novel mRNA targets, important global regulators and under physiological conditions that were considered to be incompatible with its function. PMID:24708042

Monte Carlo simulation of the neutron monitor yield function

NASA Astrophysics Data System (ADS)

Mangeard, P.-S.; Ruffolo, D.; Sáiz, A.; Madlee, S.; Nutaro, T.

2016-08-01

Neutron monitors (NMs) are ground-based detectors that measure variations of the Galactic cosmic ray flux at GV range rigidities. Differences in configuration, electronics, surroundings, and location induce systematic effects on the calculation of the yield functions of NMs worldwide. Different estimates of NM yield functions can differ by a factor of 2 or more. In this work, we present new Monte Carlo simulations to calculate NM yield functions and perform an absolute (not relative) comparison with the count rate of the Princess Sirindhorn Neutron Monitor (PSNM) at Doi Inthanon, Thailand, both for the entire monitor and for individual counter tubes. We model the atmosphere using profiles from the Global Data Assimilation System database and the Naval Research Laboratory Mass Spectrometer, Incoherent Scatter Radar Extended model. Using FLUKA software and the detailed geometry of PSNM, we calculated the PSNM yield functions for protons and alpha particles. An agreement better than 9% was achieved between the PSNM observations and the simulated count rate during the solar minimum of December 2009. The systematic effect from the electronic dead time was studied as a function of primary cosmic ray rigidity at the top of the atmosphere up to 1 TV. We show that the effect is not negligible and can reach 35% at high rigidity for a dead time >1 ms. We analyzed the response function of each counter tube at PSNM using its actual dead time, and we provide normalization coefficients between count rates for various tube configurations in the standard NM64 design that are valid to within ˜1% for such stations worldwide.

Note: An improved 3D imaging system for electron-electron coincidence measurements

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

Lin, Yun Fei; Lee, Suk Kyoung; Adhikari, Pradip

We demonstrate an improved imaging system that can achieve highly efficient 3D detection of two electrons in coincidence. The imaging system is based on a fast frame complementary metal-oxide semiconductor camera and a high-speed waveform digitizer. We have shown previously that this detection system is capable of 3D detection of ions and electrons with good temporal and spatial resolution. Here, we show that with a new timing analysis algorithm, this system can achieve an unprecedented dead-time (<0.7 ns) and dead-space (<1 mm) when detecting two electrons. A true zero dead-time detection is also demonstrated.

Note: An improved 3D imaging system for electron-electron coincidence measurements

NASA Astrophysics Data System (ADS)

Lin, Yun Fei; Lee, Suk Kyoung; Adhikari, Pradip; Herath, Thushani; Lingenfelter, Steven; Winney, Alexander H.; Li, Wen

2015-09-01

We demonstrate an improved imaging system that can achieve highly efficient 3D detection of two electrons in coincidence. The imaging system is based on a fast frame complementary metal-oxide semiconductor camera and a high-speed waveform digitizer. We have shown previously that this detection system is capable of 3D detection of ions and electrons with good temporal and spatial resolution. Here, we show that with a new timing analysis algorithm, this system can achieve an unprecedented dead-time (<0.7 ns) and dead-space (<1 mm) when detecting two electrons. A true zero dead-time detection is also demonstrated.

New insight into the residual inactivation of Microcystis aeruginosa by dielectric barrier discharge

PubMed Central

Li, Lamei; Zhang, Hong; Huang, Qing

2015-01-01

We report the new insight into the dielectric barrier discharge (DBD) induced inactivation of Microcystis aeruginosa, the dominant algae which caused harmful cyanobacterial blooms in many developing countries. In contrast with the previous work, we employed flow cytometry to examine the algal cells, so that we could assess the dead and living cells with more accuracy, and distinguish an intermediate state of algal cells which were verified as apoptotic. Our results showed that the numbers of both dead and apoptotic cells increased with DBD treatment delay time, and hydrogen peroxide produced by DBD was the main reason for the time-delayed inactivation effect. However, apart from the influence of hydrogen peroxide, the DBD-induced initial injures on the algal cells during the discharge period also played a considerable role in the inactivation of the DBD treated cells, as indicated by the measurement of intracellular reactive oxygen species (ROS) inside the algal cells. We therefore propose an effective approach to utilization of non-thermal plasma technique that makes good use of the residual inactivation effect to optimize the experimental conditions in terms of discharge time and delay time, so that more efficient treatment of cyanobacterial blooms can be achieved. PMID:26347270

Uptake of dietary PCB by pregnant big brown bats (Eptesicus fuscus) and their fetuses

USGS Publications Warehouse

Clark, D.R.

1978-01-01

In a previous study (CLARK and LAMONT 1976), 26 pregnant big brown bats were captured, caged, and fed uncontaminated mealworms until their litters were born. Immediately after parturition, female bats and litters were frozen. Five litters included at least one dead young, and these five litters contained significantly more of the PCB, Aroclor 1260, than did the 21 litters with only living young....The present study attempted to verify that Aroclor 1260 could cause stillbirths. I fed 18 of 36 pregnant big brown bats mealworms containing 6.36 ppm of Aroclor 1260 prior to birth of their litters. Both carcasses and litters of dosed females contained approximately 10 times more PCB than their respective controls, but no additional stillbirths resulted. Three of 18 control litters included dead young, whereas the comparable ratio among litters from dosed females was one of 18. Additional comparisons involving means of litter weight, adult female weight, parturition date, days in captivity, tooth wear, and percentage fat also failed to show any effect of the PCB....The association found earlier between PCB and dead young (CLARK and LAMONT 1976) was not one of cause and effect. In both studies, bats that had not been dosed showed greater PCB residues among younger females. Among control bats in the present series, females that produced dead young were significantly younger (that is, showed significantly less tooth wear) than other females. In sum, whereas dead young seemed to have been caused by greater residues, these two factors were actually independent of each other but associated with a third factor--age of the female parent bat.

Robust adaptive precision motion control of hydraulic actuators with valve dead-zone compensation.

PubMed

Deng, Wenxiang; Yao, Jianyong; Ma, Dawei

2017-09-01

This paper addresses the high performance motion control of hydraulic actuators with parametric uncertainties, unmodeled disturbances and unknown valve dead-zone. By constructing a smooth dead-zone inverse, a robust adaptive controller is proposed via backstepping method, in which adaptive law is synthesized to deal with parametric uncertainties and a continuous nonlinear robust control law to suppress unmodeled disturbances. Since the unknown dead-zone parameters can be estimated by adaptive law and then the effect of dead-zone can be compensated effectively via inverse operation, improved tracking performance can be expected. In addition, the disturbance upper bounds can also be updated online by adaptive laws, which increases the controller operability in practice. The Lyapunov based stability analysis shows that excellent asymptotic output tracking with zero steady-state error can be achieved by the developed controller even in the presence of unmodeled disturbance and unknown valve dead-zone. Finally, the proposed control strategy is experimentally tested on a servovalve controlled hydraulic actuation system subjected to an artificial valve dead-zone. Comparative experimental results are obtained to illustrate the effectiveness of the proposed control scheme. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Dynamic effects of adrenaline (epinephrine) in out-of-hospital cardiac arrest with initial pulseless electrical activity (PEA).

PubMed

Nordseth, Trond; Olasveengen, Theresa Mariero; Kvaløy, Jan Terje; Wik, Lars; Steen, Petter Andreas; Skogvoll, Eirik

2012-08-01

In cardiac arrest, pulseless electrical activity (PEA) is a challenging clinical syndrome. In a randomized study comparing intravenous (i.v.) access and drugs versus no i.v. access or drugs during advanced life support (ALS), adrenaline (epinephrine) improved return of spontaneous circulation (ROSC) in patients with PEA. Originating from this study, we investigated the time-dependent effects of adrenaline on clinical state transitions in patients with initial PEA, using a non-parametric multi-state statistical model. Patients with available defibrillator recordings were included, of whom 101 received adrenaline and 73 did not. There were significantly more state transitions in the adrenaline group than in the no-adrenaline group (rate ratio = 1.6, p<0.001). Adrenaline markedly increased the rate of transition from PEA to ROSC during ALS and slowed the rate of being declared dead; e.g. by 20 min 20% of patients in the adrenaline group had been declared dead and 25% had obtained ROSC, whereas 50% in the no-adrenaline group have been declared dead and 15% had obtained ROSC. The differential effect of adrenaline could be seen after approx. 10 min of ALS for most transitions. For both groups the probability of deteriorating from PEA to asystole was highest during the first 15 min. Adrenaline increased the rate of transition from PEA to ventricular fibrillation or -tachycardia (VF/VT), and from ROSC to VF/VT. Adrenaline has notable clinical effects during ALS in patients with initial PEA. The drug extends the time window for ROSC to develop, but also renders the patient more unstable. Further research should investigate the optimal dose, timing and mode of adrenaline administration during ALS. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Monitoring the Dead Sea Region by Multi-Parameter Stations

NASA Astrophysics Data System (ADS)

Mohsen, A.; Weber, M. H.; Kottmeier, C.; Asch, G.

2015-12-01

The Dead Sea Region is an exceptional ecosystem whose seismic activity has influenced all facets of the development, from ground water availability to human evolution. Israelis, Palestinians and Jordanians living in the Dead Sea region are exposed to severe earthquake hazard. Repeatedly large earthquakes (e.g. 1927, magnitude 6.0; (Ambraseys, 2009)) shook the whole Dead Sea region proving that earthquake hazard knows no borders and damaging seismic events can strike anytime. Combined with the high vulnerability of cities in the region and with the enormous concentration of historical values this natural hazard results in an extreme earthquake risk. Thus, an integration of earthquake parameters at all scales (size and time) and their combination with data of infrastructure are needed with the specific aim of providing a state-of-the-art seismic hazard assessment for the Dead Sea region as well as a first quantitative estimate of vulnerability and risk. A strong motivation for our research is the lack of reliable multi-parameter ground-based geophysical information on earthquakes in the Dead Sea region. The proposed set up of a number of observatories with on-line data access will enable to derive the present-day seismicity and deformation pattern in the Dead Sea region. The first multi-parameter stations were installed in Jordan, Israel and Palestine for long-time monitoring. All partners will jointly use these locations. All stations will have an open data policy, with the Deutsches GeoForschungsZentrum (GFZ, Potsdam, Germany) providing the hard and software for real-time data transmission via satellite to Germany, where all partners can access the data via standard data protocols.

WHY ARE PULSAR PLANETS RARE?

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

Martin, Rebecca G.; Livio, Mario; Palaniswamy, Divya

Pulsar timing observations have revealed planets around only a few pulsars. We suggest that the rarity of these planets is due mainly to two effects. First, we show that the most likely formation mechanism requires the destruction of a companion star. Only pulsars with a suitable companion (with an extreme mass ratio) are able to form planets. Second, while a dead zone (a region of low turbulence) in the disk is generally thought to be essential for planet formation, it is most probably rare in disks around pulsars, because of the irradiation from the pulsar. The irradiation strongly heats themore » inner parts of the disk, thus pushing the inner boundary of the dead zone out. We suggest that the rarity of pulsar planets can be explained by the low probability for these two requirements to be satisfied: a very low-mass companion and a dead zone.« less

Increased dead space in face mask continuous positive airway pressure in neonates.

PubMed

Hishikawa, Kenji; Fujinaga, Hideshi; Ito, Yushi

2017-01-01

Continuous positive airway pressure (CPAP) by face mask is commonly performed in newborn resuscitation. We evaluated the effect of face mask CPAP on system dead space. Face mask CPAP increases dead space. A CPAP model study. We estimated the volume of the inner space of the mask. We devised a face mask CPAP model, in which the outlet of the mask was covered with plastic; and three modified face mask CPAP models, in which holes were drilled near to the cushion of the covered face mask to alter the air exit. We passed a continuous flow of 21% oxygen through each model and we controlled the inner pressure to 5 cmH 2 O by adjusting the flow-relief valve. To evaluate the ventilation in the inner space of each model, we measured the oxygen concentration rise time, that is, the time needed for the oxygen concentration of each model to reach 35% after the oxygen concentration of the continuous flow was raised from 21% to 40%. The volume of inner space of the face mask was 38.3 ml. Oxygen concentration rise time in the face mask CPAP model was significantly longer at various continuous flow rates and points of the inner space of the face mask compared with that of the modified face mask CPAP model. Our study indicates that face mask CPAP leads to an increase in dead space and a decrease in ventilation efficiency under certain circumstances. Pediatr Pulmonol. 2017;52:107-111. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Growth responses of mature loblolly pine to dead wood manipulations

Treesearch

Michael D. Ulyshen; Scott Horn; James L. Hanula

2012-01-01

Large-scale manipulations of dead wood in mature Pinus taeda L. stands in the southeastern United States included a major one-time input of logs (fivefold increase in log volume) created by felling trees onsite, annual removals of all dead wood above ≥10 cm in diameter and ≥60 cm in length, and a reference in which no...

Controls on terrestrial carbon feedbacks by productivity versus turnover in the CMIP5 Earth System Models

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

Koven, C. D.; Chambers, J. Q.; Georgiou, K.

To better understand sources of uncertainty in projections of terrestrial carbon cycle feedbacks, we present an approach to separate the controls on modeled carbon changes. We separate carbon changes into four categories using a linearized, equilibrium approach: those arising from changed inputs (productivity-driven changes), and outputs (turnover-driven changes), of both the live and dead carbon pools. Using Coupled Model Intercomparison Project Phase 5 (CMIP5) simulations for five models, we find that changes to the live pools are primarily explained by productivity-driven changes, with only one model showing large compensating changes to live carbon turnover times. For dead carbon pools, themore » situation is more complex as all models predict a large reduction in turnover times in response to increases in productivity. This response arises from the common representation of a broad spectrum of decomposition turnover times via a multi-pool approach, in which flux-weighted turnover times are faster than mass-weighted turnover times. This leads to a shift in the distribution of carbon among dead pools in response to changes in inputs, and therefore a transient but long-lived reduction in turnover times. Since this behavior, a reduction in inferred turnover times resulting from an increase in inputs, is superficially similar to priming processes, but occurring without the mechanisms responsible for priming, we call the phenomenon "false priming", and show that it masks much of the intrinsic changes to dead carbon turnover times as a result of changing climate. These patterns hold across the fully coupled, biogeochemically coupled, and radiatively coupled 1 % yr −1 increasing CO 2 experiments. We disaggregate inter-model uncertainty in the globally integrated equilibrium carbon responses to initial turnover times, initial productivity, fractional changes in turnover, and fractional changes in productivity. For both the live and dead carbon pools, inter-model spread in carbon changes arising from initial conditions is dominated by model disagreement on turnover times, whereas inter-model spread in carbon changes from fractional changes to these terms is dominated by model disagreement on changes to productivity in response to both warming and CO 2 fertilization. However, the lack of changing turnover time control on carbon responses, for both live and dead carbon pools, in response to the imposed forcings may arise from a common lack of process representation behind changing turnover times (e.g., allocation and mortality for live carbon; permafrost, microbial dynamics, and mineral stabilization for dead carbon), rather than a true estimate of the importance of these processes.« less

Controls on terrestrial carbon feedbacks by productivity versus turnover in the CMIP5 Earth System Models

DOE PAGES

Koven, C. D.; Chambers, J. Q.; Georgiou, K.; ...

2015-09-07

To better understand sources of uncertainty in projections of terrestrial carbon cycle feedbacks, we present an approach to separate the controls on modeled carbon changes. We separate carbon changes into four categories using a linearized, equilibrium approach: those arising from changed inputs (productivity-driven changes), and outputs (turnover-driven changes), of both the live and dead carbon pools. Using Coupled Model Intercomparison Project Phase 5 (CMIP5) simulations for five models, we find that changes to the live pools are primarily explained by productivity-driven changes, with only one model showing large compensating changes to live carbon turnover times. For dead carbon pools, themore » situation is more complex as all models predict a large reduction in turnover times in response to increases in productivity. This response arises from the common representation of a broad spectrum of decomposition turnover times via a multi-pool approach, in which flux-weighted turnover times are faster than mass-weighted turnover times. This leads to a shift in the distribution of carbon among dead pools in response to changes in inputs, and therefore a transient but long-lived reduction in turnover times. Since this behavior, a reduction in inferred turnover times resulting from an increase in inputs, is superficially similar to priming processes, but occurring without the mechanisms responsible for priming, we call the phenomenon "false priming", and show that it masks much of the intrinsic changes to dead carbon turnover times as a result of changing climate. These patterns hold across the fully coupled, biogeochemically coupled, and radiatively coupled 1 % yr −1 increasing CO 2 experiments. We disaggregate inter-model uncertainty in the globally integrated equilibrium carbon responses to initial turnover times, initial productivity, fractional changes in turnover, and fractional changes in productivity. For both the live and dead carbon pools, inter-model spread in carbon changes arising from initial conditions is dominated by model disagreement on turnover times, whereas inter-model spread in carbon changes from fractional changes to these terms is dominated by model disagreement on changes to productivity in response to both warming and CO 2 fertilization. However, the lack of changing turnover time control on carbon responses, for both live and dead carbon pools, in response to the imposed forcings may arise from a common lack of process representation behind changing turnover times (e.g., allocation and mortality for live carbon; permafrost, microbial dynamics, and mineral stabilization for dead carbon), rather than a true estimate of the importance of these processes.« less

Feasibility study of cytokine removal by hemoadsorption in brain-dead humans.

PubMed

Kellum, John A; Venkataraman, Ramesh; Powner, David; Elder, Michele; Hergenroeder, Georgene; Carter, Melinda

2008-01-01

Inflammatory cytokines occur in the circulation and in the tissues after brain death and have been associated with dysfunction of donor organs before and after transplantation. To determine the feasibility of removing cytokines using a hemoadsorption device. Two-center, randomized, open-label, feasibility study in which brain-dead subjects were randomized to two treatment groups. Two U.S. academic hospitals. Eight brain-dead subjects deemed unsuitable for organ donation by respective organ procurement organizations. After obtaining consent from families, subjects were treated with hemoadsorption for 4 hrs using CytoSorb. Effects on cytokines (tumor necrosis factor, interleukin [IL]-6, and IL-10) were assessed both across the device and in the plasma over time. Feasibility for cytokine removal was assessed using objective criteria. Cytokine removal across the CytoSorb device ranged from 4% to 30% and was not significantly different from 1 hr to 4 hrs. Overall removal was greatest for IL-6, 28% (p = .006), and least for tumor necrosis factor, 8.5% (p = .13). Plasma concentrations of both IL-6 and tumor necrosis factor, but not IL-10, were significantly reduced after the first hour of therapy; mean differences were -13% +/- 7% for IL-6 (p = .039), -23% +/- 9% for tumor necrosis factor (p = .02), and -2% +/- 7% of IL-10 (p = 23). However, plasma concentrations for all three cytokines increased over time and were above baseline by the end of the intervention. No adverse effects of therapy were observed. However, removal of cortisol and triiodothyronine was similar to removal of cytokines. Hemoadsorption for removal of cytokines in brain-dead subjects is feasible. Evaluation of possible clinical benefit will require controlled trials in actual donors. However, the significant capacity for cytokine removal and absence of adverse events suggest that such trials are warranted.

Wind-Tunnel Investigations of Diving Brakes

NASA Technical Reports Server (NTRS)

Fucha, D.

1942-01-01

Unduly high diving speeds can be effectively controlled by diving brakes but their employment involves at the same time a number of disagreeable features: namely, rotation of zero lift direction, variation of diviving moment, and, the creation of a potent dead air region.

Implementation and Initial Testing of Advanced Processing and Analysis Algorithms for Correlated Neutron Counting

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

Santi, Peter Angelo; Cutler, Theresa Elizabeth; Favalli, Andrea

In order to improve the accuracy and capabilities of neutron multiplicity counting, additional quantifiable information is needed in order to address the assumptions that are present in the point model. Extracting and utilizing higher order moments (Quads and Pents) from the neutron pulse train represents the most direct way of extracting additional information from the measurement data to allow for an improved determination of the physical properties of the item of interest. The extraction of higher order moments from a neutron pulse train required the development of advanced dead time correction algorithms which could correct for dead time effects inmore » all of the measurement moments in a self-consistent manner. In addition, advanced analysis algorithms have been developed to address specific assumptions that are made within the current analysis model, namely that all neutrons are created at a single point within the item of interest, and that all neutrons that are produced within an item are created with the same energy distribution. This report will discuss the current status of implementation and initial testing of the advanced dead time correction and analysis algorithms that have been developed in an attempt to utilize higher order moments to improve the capabilities of correlated neutron measurement techniques.« less

Prevention and treatment effects of edible berries for three deadly diseases: Cardiovascular disease, cancer and diabetes.

PubMed

Yang, Hua; Tian, Tiantian; Wu, Dianhui; Guo, Dejun; Lu, Jian

2018-01-30

Cardiovascular disease (CVD), cancer and diabetes are serious threat to human health and more and more aroused people's attention. It is important to find the safe and effective prevention and treatment methods for the three deadly diseases. At present, a generally attention in the possible positive effects of edible berries for the three deadly diseases has been noted. Berry phytochemical compounds regulate different signaling pathways about cell survival, growth and differentiation. They contribute to the prevention and treatment of CVD, cancer and diabetes. This article reviews previous experimental evidence, several common berry phytochemical compounds and their possible mechanisms involved in three deadly diseases were summarized.

Diurnal Course of Evaporation From the Dead Sea in Summer: A Distinct Double Peak Induced by Solar Radiation and Night Sea Breeze

NASA Astrophysics Data System (ADS)

Lensky, N. G.; Lensky, I. M.; Peretz, A.; Gertman, I.; Tanny, J.; Assouline, S.

2018-01-01

Partitioning between the relative effects of the radiative and aerodynamic components of the atmospheric forcing on evaporation is challenging since diurnal distributions of wind speed and solar radiation typically overlap. The Dead Sea is located about a 100 km off the Eastern Mediterranean coast, where and the Mediterranean Sea breeze front reaches it after sunset. Therefore, in the Dead Sea the peaks of solar radiation and wind speed diurnal cycles in the Dead Sea are distinctly separated in time, offering a unique opportunity to distinguish between their relative impacts on evaporation. We present mid-summer eddy covariance and meteorological measurements of evaporation rate and surface energy fluxes over the Dead Sea. The evaporation rate is characterized by a clear diurnal cycle with a daytime peak, few hours after solar radiation peak, and a nighttime peak coincident with wind speed peak. Evaporation rate is minimum during sunrise and sunset. Measurements of evaporation rate from two other water bodies that are closer to the Mediterranean coast, Eshkol Reservoir, and Lake Kinneret, present a single afternoon peak, synchronous with the sea breeze. The inland diurnal evaporation rate cycle varies with the distance from the Mediterranean coast, following the propagation of sea breeze front: near the coast, wind speed, and radiation peaks are close and consequently a single daily evaporation peak appears in the afternoon; at the Dead Sea, about a 100 km inland, the sea breeze front arrives at sunset, resulting in a diurnal evaporation cycle characterized by a distinct double peak.

Dead-wood addition promotes non-saproxylic epigeal arthropods but effects are mediated by canopy openness

Treesearch

Sebastian Seibold; Claus Bässler; Petr Baldrian; Lena Reinhard; Simon Thorn; Michael D. Ulyshen; Ingmar Weiß; Jörg Müller

2016-01-01

Restoring dead-wood amounts in forests is an increasingly and successfully applied conservation measure to counteract negative effects of intensive logging on biodiversity of saproxylic taxa. By contrast, if and how dead-wood addition benefits the vast number of non-saproxylic forest taxa, and how this varies with contextual factors like canopy openness, remains poorly...

Some effects of aldrin-treated rice on Gulf Coast wildlife

USGS Publications Warehouse

Flickinger, Edward L.; King, K.A.

1972-01-01

Wildlife casualties from aldrin-dieldrin poisoning are associated with the planting of aldrin-treated rice seed along the Texas Gulf Coast. The fulvous tree duck (Dendrocygna bicolor), which depends on the rice field habitats and is highly susceptible to aldrin-dieldrin poisoning, is suffering a serious population decline in that area. Dead waterfowl, shorebirds, and passerines were collected on study areas in Wharton, Brazoria, and Chambers counties, Texas, from 1967 through 1971. Residues of aldrin or dieldrin were found in all samples of bird casualties and in all eggs, scavengers, predators, fish, frogs, invertebrates, and soils. Fulvous tree ducks appeared to be less resistant to aldrin than other ducks. Dieldrin residues in brains of dead fulvous tree ducks were low, but whole-body residues were as high as 16 ppm. Brains of other dead ducks and geese averaged 10 ppm dieldrin. Some dead birds were exposed by eating treated rice seed, but many dead birds with high dieldrin residues were species that feed largely on invertebrates. Although soil residues were low, snails and crayfish contained enough aldrin and dieldrin (average 9.5 ppm) to account for deaths in birds that fed heavily on these invertebrates over a period of time. When fulvous tree ducks were penned for 3 days in fields aerially planted with treated seed, 3 of 10 birds died with brain residues of 2.5, 2.9, and 6.8 ppm dieldrin, and others were intoxicated. None of eight died, and some gained weight, when penned in fields planted with untreated seed. This study adds further evidence for the suspected lethal effects of aldrin-treated rice seed on wild birds and other wildlife in rice field habitats.

The ATP/DNA Ratio Is a Better Indicator of Islet Cell Viability Than the ADP/ATP Ratio

PubMed Central

Suszynski, T.M.; Wildey, G.M.; Falde, E.J.; Cline, G.W.; Maynard, K. Stewart; Ko, N.; Sotiris, J.; Naji, A.; Hering, B.J.; Papas, K.K.

2009-01-01

Real-time, accurate assessment of islet viability is critical for avoiding transplantation of nontherapeutic preparations. Measurements of the intracellular ADP/ATP ratio have been recently proposed as useful prospective estimates of islet cell viability and potency. However, dead cells may be rapidly depleted of both ATP and ADP, which would render the ratio incapable of accounting for dead cells. Since the DNA of dead cells is expected to remain stable over prolonged periods of time (days), we hypothesized that use of the ATP/DNA ratio would take into account dead cells and may be a better indicator of islet cell viability than the ADP/ATP ratio. We tested this hypothesis using mixtures of healthy and lethally heat-treated (HT) rat insulinoma cells and human islets. Measurements of ATP/DNA and ADP/ATP from the known mixtures of healthy and HT cells and islets were used to evaluate how well these parameters correlated with viability. The results indicated that ATP and ADP were rapidly (within 1 hour) depleted in HT cells. The fraction of HT cells in a mixture correlated linearly with the ATP/DNA ratio, whereas the ADP/ADP ratio was highly scattered, remaining effectively unchanged. Despite similar limitations in both ADP/ADP and ATP/DNA ratios, in that ATP levels may fluctuate significantly and reversibly with metabolic stress, the results indicated that ATP/DNA was a better measure of islet viability than the ADP/ATP ratio. PMID:18374063

Avalanche photodiode photon counting receivers for space-borne lidars

NASA Technical Reports Server (NTRS)

Sun, Xiaoli; Davidson, Frederic M.

1991-01-01

Avalanche photodiodes (APD) are studied for uses as photon counting detectors in spaceborne lidars. Non-breakdown APD photon counters, in which the APD's are biased below the breakdown point, are shown to outperform: (1) conventional APD photon counters biased above the breakdown point; (2) conventional APD photon counters biased above the breakdown point; and (3) APD's in analog mode when the received optical signal is extremely weak. Non-breakdown APD photon counters were shown experimentally to achieve an effective photon counting quantum efficiency of 5.0 percent at lambda = 820 nm with a dead time of 15 ns and a dark count rate of 7000/s which agreed with the theoretically predicted values. The interarrival times of the counts followed an exponential distribution and the counting statistics appeared to follow a Poisson distribution with no after pulsing. It is predicted that the effective photon counting quantum efficiency can be improved to 18.7 percent at lambda = 820 nm and 1.46 percent at lambda = 1060 nm with a dead time of a few nanoseconds by using more advanced commercially available electronic components.

Assessing the role of natural disturbance and forest management on dead wood dynamics in mixed-species stands of central Maine, USA

Treesearch

Joshua J. Puhlick; Aaron R. Weiskittel; Shawn Fraver; Matthew B. Russell; Laura S. Kenefic

2016-01-01

Dead wood pools are strongly influenced by natural disturbance events, stand development processes, and forest management activities. However, the relative importance of these influences can vary over time. In this study, we evaluate the role of these factors on dead wood biomass pools across several forest management alternatives after 60 years of treatment on the...

[Studies on antimicrobial concentrations of flomoxef in serum, pelvic dead space exudate, and pelvic organs/tissues].

PubMed

Obata, T; Koishi, K; Sasaki, J; Eguchi, M; Yamamoto, Y

1987-10-01

To women undergoing radical and total hysterectomy, flomoxef (FMOX, 6315-S) in a dose of 2 g was administered by intravenous drip infusion over 1 hour and drug concentrations in serum and pelvic dead space exudate as well as pelvic organs/tissues were determined over time. The following results were obtained: 1. Serum concentrations of FMOX after intravenous infusion showed the peak value of 92.86 +/- 17.05 micrograms/ml at the end of infusion and then gradually decreased to 29.00 +/- 10.49 micrograms/ml in 1 hour and 1.16 +/- 1.08 micrograms/ml in 6 hours. 2. Concentrations in pelvic dead space exudate, which were 6.54 +/- 3.21 micrograms/ml at the end of intravenous infusion, gradually increased to 31.28 +/- 12.69 micrograms/ml in 30 minutes, and the peak of 35.21 +/- 13.29 micrograms/ml in 1 hour. Exudate concentrations gradually decreased to 11.10 +/- 6.64 micrograms/ml at 6 hours after infusion. 3. The serum concentration at the ligature of uterine artery was 103.21 +/- 51.69 micrograms/ml. Among concentrations in pelvic organ/tissues 37.17 +/- 18.20 micrograms/ml in uterine cervix was the highest, followed by 35.77 +/- 7.68 micrograms/g in portio vaginalis, 26.35 +/- 14.15 micrograms/g in tube, 21.62 +/- 12.15 micrograms/g in ovary, 20.56 +/- 9.82 micrograms/g in myometrium, and 16.45 +/- 8.10 micrograms/g in endometrium, in this order. 4. From an analysis of the two-compartment model, the maximum serum concentration was 92.81 micrograms/ml, which was very high. The time of 50% reduction of concentration in beta phase was 1.21 hours. In the pelvic dead space exudate, the maximum concentration was 32.38 micrograms/ml and the time of 50% reduction was 2.44 hours. The AUC was 147 micrograms.hr/ml in serum and 201 micrograms.hr/ml in the pelvic dead space. The shift to the pelvic dead space was 137% when AUC's were used as the basis of the comparison. 5. Clinically, FMOX was excellently effective against adnexitis caused by Peptostreptococcus asaccharolyticus, intrauterine infection caused by Staphylococcus aureus, cystitis caused by Klebsiella and Escherichia coli, vaginal stump infection caused by Streptococcus and E. coli and many other infections.

Effects of inspired CO2, hyperventilation, and time on VA/Q inequality in the dog

NASA Technical Reports Server (NTRS)

Tsukimoto, K.; Arcos, J. P.; Schaffartzik, W.; Wagner, P. D.; West, J. B.

1992-01-01

In a recent study by Tsukimoto et al. (J. Appl. Physiol. 68: 2488-2493, 1990), CO2 inhalation appeared to reduce the size of the high ventilation-perfusion ratio (VA/Q) mode commonly observed in anesthetized mechanically air-ventilated dogs. In that study, large tidal volumes (VT) were used during CO2 inhalation to preserve normocapnia. To separate the influences of CO2 and high VT on the VA/Q distribution in the present study, we examined the effect of inspired CO2 on the high VA/Q mode using eight mechanically ventilated dogs (4 given CO2, 4 controls). The VA/Q distribution was measured first with normal VT and then with increased VT. In the CO2 group at high VT, data were collected before, during, and after CO2 inhalation. With normal VT, there was no difference in the size of the high VA/Q mode between groups [10.5 +/- 3.5% (SE) of ventilation in the CO2 group, 11.8 +/- 5.2% in the control group]. Unexpectedly, the size of the high VA/Q mode decreased similarly in both groups over time, independently of the inspired PCO2, at a rate similar to the fall in cardiac output over time. The reduction in the high VA/Q mode together with a simultaneous increase in alveolar dead space (estimated by the difference between inert gas dead space and Fowler dead space) suggests that poorly perfused high VA/Q areas became unperfused over time. A possible mechanism is that elevated alveolar pressure and decreased cardiac output eliminate blood flow from corner vessels in nondependent high VA/Q regions.

The Ultrathin Limit and Dead-layer Effects in Local Polarization Switching of BiFeO3

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

Maksymovych, Petro; Huijben, Mark; Pan, Minghu

Using piezoresponse force microscopy in ultra-high vacuum, polarization switching has been detected and quantified in epitaxial BiFeO3 films from 200 down to ~ 4 unit cells. Local remnant piezoresponse was used to infer the applied electric field inside the ferroelectric volume, and account for the elusive effect of dead-layers in ultrathin films. The dead-layer manifested itself in the slower than anticipated decrease of the switching bias with film thickness, yielding apparent Kay-Dunn scaling of the switching field, while the statistical analysis of hysteresis loops revealed lateral variation of the dead-layer with sub-10 nm resolution.

Detection of viable Salmonella in ice cream by TaqMan real-time polymerase chain reaction assay combining propidium monoazide.

PubMed

Wang, Yuexia; Yang, Ming; Liu, Shuchun; Chen, Wanyi; Suo, Biao

2015-09-01

Real-time polymerase chain reaction (PCR) allows rapid detection of Salmonella in frozen dairy products, but it might cause a false positive detection result because it might amplify DNA from dead target cells as well. In this study, Salmonella-free frozen ice cream was initially inoculated with heat-killed Salmonella Typhimurium cells and stored at -18°C. Bacterial DNA extracted from the sample was amplified using TaqMan probe-based real-time PCR targeting the invA gene. Our results indicated that DNA from the dead cells remained stable in frozen ice cream for at least 20 days, and could produce fluorescence signal for real-time PCR as well. To overcome this limitation, propidium monoazide (PMA) was combined with real-time PCR. PMA treatment can effectively prevent PCR amplification from heat-killed Salmonella cells in frozen ice cream. The PMA real-time PCR assay can selectively detect viable Salmonella at as low as 10 3  CFU/mL. Combining 18 hours of pre-enrichment with the assay allows for the detection of viable Salmonella at 10 0  CFU/mL and avoiding the false-positive result of dead cells. The PMA real-time PCR assay provides an alternative specifically for detection of viable Salmonella in ice cream. However, when the PMA real-time PCR assay was evaluated in ice cream subjected to frozen storage, it obviously underestimated the contamination situation of viable Salmonella, which might lead to a false negative result. According to this result, the use of enrichment prior to PMA real-time PCR analysis remains as the more appropriate approach. Copyright © 2015. Published by Elsevier B.V.

The Effects of the Mountain Pine Beetle on Snow Accumulation and Melt Timing in the Headwaters of the Colorado River

NASA Astrophysics Data System (ADS)

Pugh, E. T.; Small, E. E.

2010-12-01

The high-elevation forests that are a primary source for Colorado’s domestic and agricultural water needs are changing rapidly due to an infestation by the mountain pine beetle (MPB). MPB are native to Colorado’s high elevation forests. However, the frequency of MPB infestation and resulting tree death has increased dramatically over the past 15 years. In Colorado, over 8,000 km2 of Lodgepole (Pinus contorta) and Ponderosa Pine (Pinus ponderosa) forest have been infested by MPB since 1996. It is predicted that the current epidemic will kill most of the pines in these areas; MPB are very destructive to forest canopies, often killing all of the overhead trees within lodgepole pine stands. Current widespread MPB outbreaks are not limited to Colorado; they are also impacting forests in much of the Western US and British Columbia, Canada. This study is focused on quantifying the impacts of widespread tree death on Colorado’s mountain snowpack. The data were collected one to three years after beetle infestation, at various stages of tree mortality. During the winters of 2009 and 2010, snowpack and meteorological properties were measured at eight pairs of dead and living lodgepole pine stands. All stands are located at an elevation of 2720 ± 32m, in a subalpine region along the headwaters of the Colorado River. Trees in living stands were generally smaller in diameter and more densely populated than trees in dead stands. In the red phase of tree death, snowpack accumulated equally beneath living and dead tree stands. Additionally, snow under all tree stands became isothermal on the same date regardless of mortality. However, the snow was depleted as much as one week earlier beneath red phase dead stands. Canopy transmission of solar radiation was not consistently different between living and red phase dead stands. We noted more ground litter in red phase dead stands which would decrease snowpack albedo and lead to the snowmelt differences observed. We also performed an albedo experiment to quantify the impact of surface litter on snow albedo. Results are also reported for more advanced grey phase dead stands. Lastly, we present a conceptual model of how the primary snow processes change with time as tree mortality progresses through various stages and introduce future work.

Effects of combined linear and nonlinear periodic training on physical fitness and competition times in finswimmers.

PubMed

Yu, Kyung-Hun; Suk, Min-Hwa; Kang, Shin-Woo; Shin, Yun-A

2014-10-01

The purpose of this study was to investigate the effect of combined linear and nonlinear periodic training on physical fitness and competition times in finswimmers. The linear resistance training model (6 days/week) and nonlinear underwater training (4 days/week) were applied to 12 finswimmers (age, 16.08± 1.44 yr; career, 3.78± 1.90 yr) for 12 weeks. Body composition measures included weight, body mass index (BMI), percent fat, and fat-free mass. Physical fitness measures included trunk flexion forward, trunk extension backward, sargent jump, 1-repetition-maximum (1 RM) squat, 1 RM dead lift, knee extension, knee flexion, trunk extension, trunk flexion, and competition times. Body composition and physical fitness were improved after the 12-week periodic training program. Weight, BMI, and percent fat were significantly decreased, and trunk flexion forward, trunk extension backward, sargent jump, 1 RM squat, 1 RM dead lift, and knee extension (right) were significantly increased. The 50- and 100-m times significantly decreased in all 12 athletes. After 12 weeks of training, all finswimmers who participated in this study improved their times in a public competition. These data indicate that combined linear and nonlinear periodic training enhanced the physical fitness and competition times in finswimmers.

Influential impacts of combined government policies for safe disposal of dead pigs on farmer behavior.

PubMed

Chen, Xiujuan; Qiu, Guangqian; Wu, Linhai; Xu, Guoyan; Wang, Jianhua; Hu, Wuyang

2017-02-01

Improper disposal of dead pigs by pig farmers may have an adverse impact on the ecological environment and food safety. In this paper, disposal of dead pigs by pig farmers in four main pig production provinces in China (Jiangsu, Anhui, Hubei, and Hunan) was empirically investigated. Then, pig farmers' awareness and evaluation of current combined government policies for the safe disposal of dead pigs were analyzed. Furthermore, the influential effects of combined government policies on the disposal of dead pigs by pig farmers were examined using Decision-Making Trial and Evaluation Laboratory (DEMATEL). Results indicated that the issue of disposal of dead pigs by farmers was very complex and was influenced by the combination of subsidy and compensation, facility and technology, and supervision and punishment policies. The findings also indicated that the different types of policies had different effects and interacted with each other. Among these three combinations, supervision and punishment policies were the most influential policies and facility and technology policies were in most urgent need to improve for regulating the current state of the disposal of dead pigs by farmers. These findings have implications for sustainable pig production.

Implementation of a high precision multi-measurement time-to-digital convertor on a Kintex-7 FPGA

NASA Astrophysics Data System (ADS)

Kuang, Jie; Wang, Yonggang; Cao, Qiang; Liu, Chong

2018-05-01

Time-to-digital convertors (TDCs) based on field programmable gate array (FPGA) are becoming more and more popular. Multi-measurement is an effective method to improve TDC precision beyond the cell delay limitation. However, the implementation of TDC with multi-measurement on FPGAs manufactured with 28 nm and more advanced process is facing new challenges. Benefiting from the ones-counter encoding scheme, which was developed in our previous work, we implement a ring oscillator multi-measurement TDC on a Xilinx Kintex-7 FPGA. Using the two TDC channels to measure time-intervals in the range (0 ns-30 ns), the average RMS precision can be improved to 5.76 ps, meanwhile the logic resource usage remains the same with the one-measurement TDC, and the TDC dead time is only 22 ns. The investigation demonstrates that the multi-measurement methods are still available for current main-stream FPGAs. Furthermore, the new implementation in this paper could make the trade-off among the time precision, resource usage and TDC dead time better than ever before.

The dead donor rule: can it withstand critical scrutiny?

PubMed

Miller, Franklin G; Truog, Robert D; Brock, Dan W

2010-06-01

Transplantation of vital organs has been premised ethically and legally on "the dead donor rule" (DDR)-the requirement that donors are determined to be dead before these organs are procured. Nevertheless, scholars have argued cogently that donors of vital organs, including those diagnosed as "brain dead" and those declared dead according to cardiopulmonary criteria, are not in fact dead at the time that vital organs are being procured. In this article, we challenge the normative rationale for the DDR by rejecting the underlying premise that it is necessarily wrong for physicians to cause the death of patients and the claim that abandoning this rule would exploit vulnerable patients. We contend that it is ethical to procure vital organs from living patients sustained on life support prior to treatment withdrawal, provided that there is valid consent for both withdrawing treatment and organ donation. However, the conservatism of medical ethics and practical concerns make it doubtful that the DDR will be abandoned in the near future. This leaves the current practice of organ transplantation based on the "moral fiction" that donors are dead when vital organs are procured.

Properties of the dead zone due to the gas cushion effect in PBX 9502

NASA Astrophysics Data System (ADS)

Anderson, William

2017-06-01

The gas cushion effect is a well-known phenomenon in which gas trapped between an impactor and an explosive precompresses and deadens a layer of the explosive. We have conducted a series of impact experiments, with and without a trapped gas layer, on the plastic bonded explosive PBX 9502 (95% TATB and 5% Kel-F 800). In each experiment, a 100-oriented LiF window was glued, with an intervening Al foil (a reflector for VISAR), to the surface of a thin (2.5-3.3 mm) PBX 9502 sample and the opposite surface impacted by an impactor at a velocity sufficient to produce an overdriven detonation. VISAR was used to observe arrival of the resulting shock wave and reverberations between the LiF window and the impactor. In three experiments, a gap of 25-38 mm, filled with He gas at a pressure of 0.79 bar, existed between the impactor and the sample at the beginning of the experiment. In these three experiments, a low-amplitude wave reflected from the interface between the reacted explosive and the dead zone was observed to precede the reflection from the impactor. We have used the observed wave amplitudes and arrival times to quantify the properties of the dead zone and, by comparison to existing EOS data for reacted and unreacted PBX 9502, estimate the extent of reaction in the dead zone. This work was supported by the US Department of Energy under contract DE-AC52-06NA25396.

33 CFR 183.105 - Quantity of flotation required.

Code of Federal Regulations, 2010 CFR

2010-07-01

... of the dead weight; and (3) A weight in pounds that, when submerged, equals 62.4 times the volume in... of this section, “dead weight” means the maximum weight capacity marked on the boat minus the persons...

33 CFR 183.105 - Quantity of flotation required.

Code of Federal Regulations, 2014 CFR

2014-07-01

... of the dead weight; and (3) A weight in pounds that, when submerged, equals 62.4 times the volume in... of this section, “dead weight” means the maximum weight capacity marked on the boat minus the persons...

33 CFR 183.105 - Quantity of flotation required.

Code of Federal Regulations, 2012 CFR

2012-07-01

... of the dead weight; and (3) A weight in pounds that, when submerged, equals 62.4 times the volume in... of this section, “dead weight” means the maximum weight capacity marked on the boat minus the persons...

33 CFR 183.105 - Quantity of flotation required.

Code of Federal Regulations, 2011 CFR

2011-07-01

... of the dead weight; and (3) A weight in pounds that, when submerged, equals 62.4 times the volume in... of this section, “dead weight” means the maximum weight capacity marked on the boat minus the persons...

33 CFR 183.105 - Quantity of flotation required.

Code of Federal Regulations, 2013 CFR

2013-07-01

... of the dead weight; and (3) A weight in pounds that, when submerged, equals 62.4 times the volume in... of this section, “dead weight” means the maximum weight capacity marked on the boat minus the persons...

77 FR 12244 - Proposed Information Collection; Comment Request; Report of Whaling Operations

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-29

... American whaling organization about strikes on and catch of whales. Anyone retrieving a dead whale is also... Respondents: 51. Estimated Time Per Response: 30 minutes for reports on whales struck or on recovery of dead...

Spatio-temporal development of sinkholes on the eastern shore of the Dead Sea

NASA Astrophysics Data System (ADS)

Holohan, Eoghan; Saberi, Leila; Al-Halbouni, Djamil; Sawarieh, Ali; Closson, Damien; Alrshdan, Hussam; Walter, Thomas; Dahm, Torsten

2017-04-01

The ongoing, largely anthropogenically-forced decline of the Dead Sea is associated with the most prolific development of sinkholes worldwide. The fall in hydrological base level since the 1960s is thought to enable relatively fresh ground waters to dissolve underground salt deposits that were previously in equilibrium with hypersaline Dead Sea brine. Sinkhole development in response to this dissolution began in the 1980s and is still ongoing; it represents a significant geohazard in the Dead Sea region. We present new research undertaken within the Dead Sea Research Venue (DESERVE) on the spatio-temporal evolution of the main sinkhole-affected site on the Eastern shore of the Dead Sea, at Ghor Al-Haditha in Jordan. Our data set includes optical satellite imagery, aerial survey photographs and drone-based photogrammetric surveys with high spatial (< 1 m2 - 0.05 m per pixel) and temporal (decadal from 1970-2010, annual from 2004-2016) resolution. These enable new quantitative insights into this, the largest of all the Dead Sea sinkhole sites. Our analysis shows that there are now over 800 sinkholes at Ghor al-Haditha. Sinkholes initiated as spatially distinct clusters in the late 1980's to early 1990s. While some clusters have since become inactive, most have expanded and merged with time. New clusters have also developed, mainly in the more recently exposed north of the area. With the retreat of the Dead Sea, the roughly coastline-parallel zone of sinkhole formation has expanded unevenly but systematically seawards. Such a seaward migration of sinkhole formation is predicted from hydrogeological theory, but as yet not consistently observed elsewhere at the Dead Sea. The rate of sinkhole formation at Ghor Haditha accelerated markedly during the late 2000s to a peak of about 100 per year in 2009. Similar accelerations are observed on the western shore, but differ in timing. The rate of sinkhole formation on the Eastern shore has since declined to about 50 per year. Such differences in the overall spatio-temporal evolution of sinkholes on the eastern and western shores of the Dead Sea likely highlights the important role of local hydrogeological conditions and processes in governing sinkhole development.

PID tuning rules for SOPDT systems: review and some new results.

PubMed

Panda, Rames C; Yu, Cheng-Ching; Huang, Hsiao-Ping

2004-04-01

PID controllers are widely used in industries and so many tuning rules have been proposed over the past 50 years that users are often lost in the jungle of tuning formulas. Moreover, unlike PI control, different control laws and structures of implementation further complicate the use of the PID controller. In this work, five different tuning rules are taken for study to control second-order plus dead time systems with wide ranges of damping coefficients and dead time to time constant ratios (D/tau). Four of them are based on IMC design with different types of approximations on dead time and the other on desired closed-loop specifications (i.e., specified forward transfer function). The method of handling dead time in the IMC type of design is important especially for systems with large D/tau ratios. A systematic approach was followed to evaluate the performance of controllers. The regions of applicability of suitable tuning rules are highlighted and recommendations are also given. It turns out that IMC designed with the Maclaurin series expansion type PID is a better choice for both set point and load changes for systems with D/tau greater than 1. For systems with D/tau less than 1, the desired closed-loop specification approach is favored.

Ageing of native cellulose fibres under archaeological conditions: textiles from the Dead Sea region studied using synchrotron X-ray microdiffraction

NASA Astrophysics Data System (ADS)

Müller, M.; Murphy, B.; Burghammer, M.; Riekel, C.; Pantos, E.; Gunneweg, J.

2007-12-01

Archaeological cellulose textile fibres (linen and cotton) from caves in the Dead Sea region were investigated using synchrotron X-ray microdiffraction. The degradation of the up to 2100 year old fibres was found to depend on the climatic conditions at the place of storage. The size and the lattice parameters of the cellulose nanocrystals (microfibrils) in the fibres change upon degradation; these parameters are shown to be strongly correlated, leading to a microscopic description of the degradation process in terms of molecular disorder. Artificial ageing does not seem to reproduce the effects observed here for the first time on archaeological cellulose fibres.

A meta-analysis of predation risk effects on pollinator behaviour.

PubMed

Romero, Gustavo Q; Antiqueira, Pablo A P; Koricheva, Julia

2011-01-01

Flower-visiting animals are constantly under predation risk when foraging and hence might be expected to evolve behavioural adaptations to avoid predators. We reviewed the available published and unpublished data to assess the overall effects of predators on pollinator behaviour and to examine sources of variation in these effects. The results of our meta-analysis showed that predation risk significantly decreased flower visitation rates (by 36%) and time spent on flowers (by 51%) by pollinators. The strength of the predator effects depended neither on predator taxa and foraging mode (sit-and-wait or active hunters) nor on pollinator lifestyle (social vs. solitary). However, predator effects differed among pollinator taxa: predator presence reduced flower visitation rates and time spent on flowers by Squamata, Lepidoptera and Hymenoptera, but not by Diptera. Furthermore, larger pollinators showed weaker responses to predation risk, probably because they are more difficult to capture. Presence of live crab spiders on flowers had weaker effects on pollinator behaviour than presence of dead or artificial crab spiders or other objects (e.g. dead bees, spheres), suggesting that predator crypsis may be effective to some extent. These results add to a growing consensus on the importance of considering both predator and pollinator characteristics from a community perspective.

The politics of grief and continuing bonds with the dead: the cases of Maoist China and Wahhabi Islam.

PubMed

Klass, Dennis; Goss, Robert

2003-11-01

The article is a contribution to a cross-cultural theory of grief. It examines the relationship between individual/family continuing bonds with the dead and cultural narratives that legitimize political power. The dead are collective representations (Dirkheim) that mediate the larger culture to individuals and to smaller communities and that reinforce social solidarity and identity. The political question is which collective--family, community, church, party, nation--owns the dead and controls the rituals by which bonds with the dead are maintained or relinquished? The article discusses one historical condition: times of rapid change in power arrangements. Bonds with the dead have a power in individual, family, or tribal life that can threaten the narrative that legitimizes the new political power holders. Ancestor rituals that support identity as a family or tribal member are surpressed and replaced by allegiance to collective representations of the new political order. Two historical examples are given: China under Chairman Mao and the Wahhabi reform in Arabic Islam.

The Dead Sea Mud and Salt: A Review of Its Characterization, Contaminants, and Beneficial Effects

NASA Astrophysics Data System (ADS)

Bawab, Abeer Al; Bozeya, Ayat; Abu-Mallouh, Saida; Abu Irmaileh, Basha'er; Daqour, Ismail; Abu-Zurayk, Rund A.

2018-02-01

The Dead Sea has been known for its therapeutic and cosmetic properties. The unique climatic conditions in the Dead Sea area make it a renowned site worldwide for the field of climatotherapy, which is a natural approach for the provision of medications for many human diseases including unusual exclusive salt composition of the water, a special natural mud, thermal mineral springs, solar irradiation, oxygen-rich and bromine-rich haze. This review focuses on the physical, chemical, and biological characteristics of the Dead Sea mud and salts, in addition to their contaminants, allowing this review to serve as a guide to interested researchers to their risks and the importance of treatment. Beneficial effects of Dead Sea mud and salts are discussed in terms of therapy and cosmetics. Additional benefits of both Dead Sea mud and salts are also discussed, such as antimicrobial action of the mud in relation to its therapeutic properties, and the potency of mud and salts to be a good medium for the growth of a halophilic unicellular algae, used for the commercial production of β-carotene Dunaliella.

Novel analysis of 4DCT imaging quantifies progressive increases in anatomic dead space during mechanical ventilation in mice.

PubMed

Kim, Elizabeth H; Preissner, Melissa; Carnibella, Richard P; Samarage, Chaminda R; Bennett, Ellen; Diniz, Marcio A; Fouras, Andreas; Zosky, Graeme R; Jones, Heather D

2017-09-01

Increased dead space is an important prognostic marker in early acute respiratory distress syndrome (ARDS) that correlates with mortality. The cause of increased dead space in ARDS has largely been attributed to increased alveolar dead space due to ventilation/perfusion mismatching and shunt. We sought to determine whether anatomic dead space also increases in response to mechanical ventilation. Mice received intratracheal lipopolysaccharide (LPS) or saline and mechanical ventilation (MV). Four-dimensional computed tomography (4DCT) scans were performed at onset of MV and after 5 h of MV. Detailed measurements of airway volumes and lung tidal volumes were performed using image analysis software. The forced oscillation technique was used to obtain measures of airway resistance, tissue damping, and tissue elastance. The ratio of airway volumes to total tidal volume increased significantly in response to 5 h of mechanical ventilation, regardless of LPS exposure, and airways demonstrated significant variation in volumes over the respiratory cycle. These findings were associated with an increase in tissue elastance (decreased lung compliance) but without changes in tidal volumes. Airway volumes increased over time with exposure to mechanical ventilation without a concomitant increase in tidal volumes. These findings suggest that anatomic dead space fraction increases progressively with exposure to positive pressure ventilation and may represent a pathological process. NEW & NOTEWORTHY We demonstrate that anatomic dead space ventilation increases significantly over time in mice in response to mechanical ventilation. The novel functional lung-imaging techniques applied here yield sensitive measures of airway volumes that may have wide applications. Copyright © 2017 the American Physiological Society.

Biosorption Potential of Bacillus salmalaya Strain 139SI for Removal of Cr(VI) from Aqueous Solution.

PubMed

Dadrasnia, Arezoo; Chuan Wei, Kelvin Swee; Shahsavari, Nasser; Azirun, Mohd Sofian; Ismail, Salmah

2015-12-03

The present study investigated the biosorption capacity of live and dead cells of a novel Bacillus strain for chromium. The optimum biosorption condition was evaluated in various analytical parameters, including initial concentration of chromium, pH, and contact time. The Langmuir isotherm model showed an enhanced fit to the equilibrium data. Live and dead biomasses followed the monolayer biosorption of the active surface sites. The maximum biosorption capacity was 20.35 mg/g at 25 °C, with pH 3 and contact time of 50 min. Strain 139SI was an excellent host to the hexavalent chromium. The biosorption kinetics of chromium in the dead and live cells of Bacillus salmalaya (B. salmalaya) 139SI followed the pseudo second-order mechanism. Scanning electron microscopy and fourier transform infrared indicated significant influence of the dead cells on the biosorption of chromium based on cell morphological changes. Approximately 92% and 70% desorption efficiencies were achieved using dead and live cells, respectively. These findings demonstrated the high sorption capacity of dead biomasses of B. salmalaya 139SI in the biosorption process. Thermodynamic evaluation (ΔG⁰, ΔH⁰, and ΔS⁰) indicated that the mechanism of Cr(VI) adsorption is endothermic; that is, chemisorption. Results indicated that chromium accumulation occurred in the cell wall of B. salmalaya 139SI rather than intracellular accumulation.

Biosorption Potential of Bacillus salmalaya Strain 139SI for Removal of Cr(VI) from Aqueous Solution

PubMed Central

Dadrasnia, Arezoo; Chuan Wei, Kelvin Swee; Shahsavari, Nasser; Azirun, Mohd Sofian; Ismail, Salmah

2015-01-01

The present study investigated the biosorption capacity of live and dead cells of a novel Bacillus strain for chromium. The optimum biosorption condition was evaluated in various analytical parameters, including initial concentration of chromium, pH, and contact time. The Langmuir isotherm model showed an enhanced fit to the equilibrium data. Live and dead biomasses followed the monolayer biosorption of the active surface sites. The maximum biosorption capacity was 20.35 mg/g at 25 °C, with pH 3 and contact time of 50 min. Strain 139SI was an excellent host to the hexavalent chromium. The biosorption kinetics of chromium in the dead and live cells of Bacillus salmalaya (B. salmalaya) 139SI followed the pseudo second-order mechanism. Scanning electron microscopy and fourier transform infrared indicated significant influence of the dead cells on the biosorption of chromium based on cell morphological changes. Approximately 92% and 70% desorption efficiencies were achieved using dead and live cells, respectively. These findings demonstrated the high sorption capacity of dead biomasses of B. salmalaya 139SI in the biosorption process. Thermodynamic evaluation (ΔG0, ΔH0, and ΔS0) indicated that the mechanism of Cr(VI) adsorption is endothermic; that is, chemisorption. Results indicated that chromium accumulation occurred in the cell wall of B. salmalaya 139SI rather than intracellular accumulation. PMID:26633454

Influence of Distributed Dead Loads on Vehicle Position for Maximum Moment in Simply Supported Bridges

NASA Astrophysics Data System (ADS)

Gupta, Tanmay; Kumar, Manoj

2017-06-01

Usually, the design moments in the simply supported bridges are obtained as the sum of moments due to dead loads and live load where the live load moments are calculated using the rolling load concept neglecting the effect of dead loads. For the simply supported bridges, uniformly distributed dead load produces maximum moment at mid-span while the absolute maximum bending moment due to multi-axel vehicles occur under a wheel which usually do not lie at mid-span. Since, the location of absolute maximum bending moment due to multi-axel vehicle do not coincide with the location of maximum moment due to dead loads occurring at mid-span, the design moment may not be obtained by simply superimposing the effect of dead load and live load. Moreover, in case of Class-A and Class-70R wheeled vehicular live loads, which consists of several axels, the number of axels to be considered over the bridge of given span and their location is tedious to find out and needs several trials. The aim of the present study is to find the number of wheels for Class-A and Class-70R wheeled vehicles and their precise location to produce absolute maximum moment in the bridge considering the effect of dead loads and impact factor. Finally, in order to enable the designers, the design moments due to Class-70R wheeled and Class-A loading have been presented in tabular form for the spans from 10 to 50 m.

The effect of brain death in rat steatotic and non-steatotic liver transplantation with previous ischemic preconditioning.

PubMed

Jiménez-Castro, Mónica B; Meroño, Noelia; Mendes-Braz, Mariana; Gracia-Sancho, Jordi; Martínez-Carreres, Laia; Cornide-Petronio, Maria Eugenia; Casillas-Ramirez, Araní; Rodés, Juan; Peralta, Carmen

2015-01-01

Most liver grafts undergoing transplantation derive from brain dead donors, which may also show hepatic steatosis, being both characteristic risk factors in liver transplantation. Ischemic preconditioning shows benefits when applied in non-brain dead clinical situations like hepatectomies, whereas it has been less promising in the transplantation from brain dead patients. This study examined how brain death affects preconditioned steatotic and non-steatotic liver grafts undergoing transplantation. Steatotic and non-steatotic grafts from non-brain dead and brain dead-donors were cold stored for 6h and then transplanted. After 2, 4, and 16 h of reperfusion, hepatic damage was analysed. In addition, two therapeutic strategies, ischemic preconditioning and/or acetylcholine pre-treatment, and their underlying mechanisms were characterized. Preconditioning benefits in non-brain dead donors were associated with nitric oxide and acetylcholine generation. In brain dead donors, preconditioning generated nitric oxide but did not promote acetylcholine upregulation, and this resulted in inflammation and damage. Acetylcholine treatment in brain dead donors, through PKC, increased antioxidants and reduced lipid peroxidation, nitrotyrosines and neutrophil accumulation, altogether protecting against damage. The combination of acetylcholine and preconditioning conferred stronger protection against damage, oxidative stress and neutrophil accumulation than acetylcholine treatment alone. These superior beneficial effects were due to a selective preconditioning-mediated generation of nitric oxide and regulation of PPAR and TLR4 pathways, which were not observed when acetylcholine was administered alone. Our findings propose the combination of acetylcholine+preconditioning as a feasible and highly protective strategy to reduce the adverse effects of brain death and to ultimately improve liver graft quality. Copyright © 2014 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

Investigation of the disposal of dead pigs by pig farmers in mainland China by simulation experiment.

PubMed

Wu, Linhai; Xu, Guoyan; Li, Qingguang; Hou, Bo; Hu, Wuyang; Wang, Jianhua

2017-01-01

Dead pigs are a major waste by-product of pig farming. Thus, safe disposal of dead pigs is important to the protection of consumer health and the ecological environment by preventing marketing of slaughtered and processed dead pigs and improper dumping of dead pigs. In this study, a probability model was constructed for the disposal of dead pigs by pig farmers by selecting factors affecting disposal. To that end, we drew on the definition and meaning of behavior probability based on survey data collected from 654 pig farmers in Funing County, Jiangsu Province, China. Moreover, the role of influencing factors in pig farmers' behavioral choices regarding the disposal of dead pigs was simulated by simulation experiment. The results indicated that years of farming had a positive impact on pig farmers' choice of negative disposal of dead pigs. Moreover, there was not a simple linear relationship between scale of farming and pig farmers' behavioral choices related to the disposal of dead pigs. The probability for farmers to choose the safe disposal of dead pigs increased with the improvement of their knowledge of government policies and relevant laws and regulations. Pig farmers' behavioral choice about the disposal of dead pigs was also affected by government subsidy policies, regulation, and punishment. Government regulation and punishment were more effective than subsidy. The findings of our simulation experiment provide important decision-making support for the governance in preventing the marketing of dead pigs at the source.

Laboratory simulation of the effects of overburden stress on the specific storage of shallow artesian aquifers

USGS Publications Warehouse

Sepúlveda, Nicasio; Zack, A.L.; Krishna, J.H.; Quinones-Aponte, Vicente; Gomez-Gomez, Fernando; Morris, G.L.

1990-01-01

A laboratory experiment to measure the specific storage of an aquifer material was conducted. A known dead load, simulating an overburden load, was applied to a sample of completely saturated aquifer material contained inside a cylinder. After the dead load was applied, water was withdrawn from the sample, causing the hydrostatic pressure to decrease and the effective stress to increase. The resulting compression of the sample and the amount of water withdrawn were measured after equilibrium was reached. The procedure was repeated by increasing the dead load and the hydrostatic pressure followed by withdrawing water to determine new values of effective stress and compaction. The simulated dead loads are typical of those experienced by shallow artesian aquifers. The void ratio and the effective stress of the aquifer sample, as simulated by different dead loads, determine the pore volume compressibility which, in turn, determines the values of specific storage. An analytical algorithm was used to independently determine the stress dependent profile of specific storage. These values are found to be in close agreement with laboratory results. Implications for shallow artesian aquifers, with relatively small overburden stress, are also addressed.

Tuning rules for robust FOPID controllers based on multi-objective optimization with FOPDT models.

PubMed

Sánchez, Helem Sabina; Padula, Fabrizio; Visioli, Antonio; Vilanova, Ramon

2017-01-01

In this paper a set of optimally balanced tuning rules for fractional-order proportional-integral-derivative controllers is proposed. The control problem of minimizing at once the integrated absolute error for both the set-point and the load disturbance responses is addressed. The control problem is stated as a multi-objective optimization problem where a first-order-plus-dead-time process model subject to a robustness, maximum sensitivity based, constraint has been considered. A set of Pareto optimal solutions is obtained for different normalized dead times and then the optimal balance between the competing objectives is obtained by choosing the Nash solution among the Pareto-optimal ones. A curve fitting procedure has then been applied in order to generate suitable tuning rules. Several simulation results show the effectiveness of the proposed approach. Copyright © 2016. Published by Elsevier Ltd.

Observed-Based Adaptive Fuzzy Tracking Control for Switched Nonlinear Systems With Dead-Zone.

PubMed

Tong, Shaocheng; Sui, Shuai; Li, Yongming

2015-12-01

In this paper, the problem of adaptive fuzzy output-feedback control is investigated for a class of uncertain switched nonlinear systems in strict-feedback form. The considered switched systems contain unknown nonlinearities, dead-zone, and immeasurable states. Fuzzy logic systems are utilized to approximate the unknown nonlinear functions, a switched fuzzy state observer is designed and thus the immeasurable states are obtained by it. By applying the adaptive backstepping design principle and the average dwell time method, an adaptive fuzzy output-feedback tracking control approach is developed. It is proved that the proposed control approach can guarantee that all the variables in the closed-loop system are bounded under a class of switching signals with average dwell time, and also that the system output can track a given reference signal as closely as possible. The simulation results are given to check the effectiveness of the proposed approach.

Pulmonary Dead Space Fraction and Extubation Success in Children After Cardiac Surgery.

PubMed

Devor, Renee L; Kang, Paul; Wellnitz, Chasity; Nigro, John J; Velez, Daniel A; Willis, Brigham C

2018-04-01

1) Determine the correlation between pulmonary dead space fraction and extubation success in postoperative pediatric cardiac patients; and 2) document the natural history of pulmonary dead space fractions, dynamic compliance, and airway resistance during the first 72 hours postoperatively in postoperative pediatric cardiac patients. A retrospective chart review. Cardiac ICU in a quaternary care free-standing children's hospital. Twenty-nine with balanced single ventricle physiology, 61 with two ventricle physiology. None. We collected data for all pediatric patients undergoing congenital cardiac surgery over a 14-month period during the first 72 hours postoperatively as well as prior to extubation. Overall, patients with successful extubations had lower preextubation dead space fractions and shorter lengths of stay. Single ventricle patients had higher initial postoperative and preextubation dead space fractions. Two-ventricle physiology patients had higher extubation failure rates if the preextubation dead space fraction was greater than 0.5, whereas single ventricle patients had similar extubation failure rates whether preextubation dead space fractions were less than or equal to 0.5 or greater than 0.5. Additionally, increasing initial dead space fraction values predicted prolonged mechanical ventilation times. Airway resistance and dynamic compliance were similar between those with successful extubations and those who failed. Initial postoperative dead space fraction correlates with the length of mechanical ventilation in two ventricle patients but not in single ventricle patients. Lower preextubation dead space fractions are a strong predictor of successful extubation in two ventricle patients after cardiac surgery, but may not be as useful in single ventricle patients.

A general dead-time correction method based on live-time stamping. Application to the measurement of short-lived radionuclides.

PubMed

Chauvenet, B; Bobin, C; Bouchard, J

2017-12-01

Dead-time correction formulae are established in the general case of superimposed non-homogeneous Poisson processes. Based on the same principles as conventional live-timed counting, this method exploits the additional information made available using digital signal processing systems, and especially the possibility to store the time stamps of live-time intervals. No approximation needs to be made to obtain those formulae. Estimates of the variances of corrected rates are also presented. This method is applied to the activity measurement of short-lived radionuclides. Copyright © 2017 Elsevier Ltd. All rights reserved.

Optimization of integrated impeller mixer via radiotracer experiments.

PubMed

Othman, N; Kamarudin, S K; Takriff, M S; Rosli, M I; Engku Chik, E M F; Adnan, M A K

2014-01-01

Radiotracer experiments are carried out in order to determine the mean residence time (MRT) as well as percentage of dead zone, V dead (%), in an integrated mixer consisting of Rushton and pitched blade turbine (PBT). Conventionally, optimization was performed by varying one parameter and others were held constant (OFAT) which lead to enormous number of experiments. Thus, in this study, a 4-factor 3-level Taguchi L9 orthogonal array was introduced to obtain an accurate optimization of mixing efficiency with minimal number of experiments. This paper describes the optimal conditions of four process parameters, namely, impeller speed, impeller clearance, type of impeller, and sampling time, in obtaining MRT and V dead (%) using radiotracer experiments. The optimum conditions for the experiments were 100 rpm impeller speed, 50 mm impeller clearance, Type A mixer, and 900 s sampling time to reach optimization.

Advanced active quenching circuit for ultra-fast quantum cryptography.

PubMed

Stipčević, Mario; Christensen, Bradley G; Kwiat, Paul G; Gauthier, Daniel J

2017-09-04

Commercial photon-counting modules based on actively quenched solid-state avalanche photodiode sensors are used in a wide variety of applications. Manufacturers characterize their detectors by specifying a small set of parameters, such as detection efficiency, dead time, dark counts rate, afterpulsing probability and single-photon arrival-time resolution (jitter). However, they usually do not specify the range of conditions over which these parameters are constant or present a sufficient description of the characterization process. In this work, we perform a few novel tests on two commercial detectors and identify an additional set of imperfections that must be specified to sufficiently characterize their behavior. These include rate-dependence of the dead time and jitter, detection delay shift, and "twilighting". We find that these additional non-ideal behaviors can lead to unexpected effects or strong deterioration of the performance of a system using these devices. We explain their origin by an in-depth analysis of the active quenching process. To mitigate the effects of these imperfections, a custom-built detection system is designed using a novel active quenching circuit. Its performance is compared against two commercial detectors in a fast quantum key distribution system with hyper-entangled photons and a random number generator.

Setting Dead at Zero: Applying Scale Properties to the QALY Model.

PubMed

Roudijk, Bram; Donders, A Rogier T; Stalmeier, Peep F M

2018-04-01

Scaling severe states can be a difficult task. First, the method of measurement affects whether a health state is considered better or worse than dead. Second, in discrete choice experiments, different models to anchor health states on 0 (dead) and 1 (perfect health) produce varying amounts of health states worse than dead. Within the context of the quality-adjusted life-year (QALY) model, this article provides insight into the value assigned to dead and its consequences for decision making. Our research questions are 1) what are the arguments set forth to assign dead the number 0 on the health-utility scale? And 2) what are the effects of the position of dead on the health-utility scale on decision making? A literature review was conducted to explore the arguments set forth to assign dead a value of 0 in the QALY model. In addition, scale properties and transformations were considered. The review uncovered several practical and theoretical considerations for setting dead at 0. In the QALY model, indifference between 2 health episodes is not preserved under changes of the origin of the duration scale. Ratio scale properties are needed for the duration scale to preserve indifferences. In combination with preferences and zero conditions for duration and health, it follows that dead should have a value of 0. The health-utility and duration scales have ratio scale properties, and dead should be assigned the number 0. Furthermore, the position of dead should be carefully established, because it determines how life-saving and life-improving values are weighed in cost-utility analysis.

Neural-adaptive control of single-master-multiple-slaves teleoperation for coordinated multiple mobile manipulators with time-varying communication delays and input uncertainties.

PubMed

Li, Zhijun; Su, Chun-Yi

2013-09-01

In this paper, adaptive neural network control is investigated for single-master-multiple-slaves teleoperation in consideration of time delays and input dead-zone uncertainties for multiple mobile manipulators carrying a common object in a cooperative manner. Firstly, concise dynamics of teleoperation systems consisting of a single master robot, multiple coordinated slave robots, and the object are developed in the task space. To handle asymmetric time-varying delays in communication channels and unknown asymmetric input dead zones, the nonlinear dynamics of the teleoperation system are transformed into two subsystems through feedback linearization: local master or slave dynamics including the unknown input dead zones and delayed dynamics for the purpose of synchronization. Then, a model reference neural network control strategy based on linear matrix inequalities (LMI) and adaptive techniques is proposed. The developed control approach ensures that the defined tracking errors converge to zero whereas the coordination internal force errors remain bounded and can be made arbitrarily small. Throughout this paper, stability analysis is performed via explicit Lyapunov techniques under specific LMI conditions. The proposed adaptive neural network control scheme is robust against motion disturbances, parametric uncertainties, time-varying delays, and input dead zones, which is validated by simulation studies.

Post-fire logging reduces surface woody fuels up to four decades following wildfire

Treesearch

David W. Peterson; Erich Kyle Dodson; Richy J. Harrod

2015-01-01

Severe wildfires create pulses of dead trees that influence future fuel loads, fire behavior, and fire effects as they decay and deposit surface woody fuels. Harvesting fire-killed trees may reduce future surface woody fuels and related fire hazards, but the magnitude and timing of post-fire logging effects on woody fuels have not been fully assessed. To address this...

Numerical responses of saproxylic beetles to rapid increases in dead wood availability following geometrid moth outbreaks in sub-arctic mountain birch forest.

PubMed

Vindstad, Ole Petter Laksforsmo; Schultze, Sabrina; Jepsen, Jane Uhd; Biuw, Martin; Kapari, Lauri; Sverdrup-Thygeson, Anne; Ims, Rolf Anker

2014-01-01

Saproxylic insects play an important part in decomposing dead wood in healthy forest ecosystems, but little is known about their role in the aftermath of large-scale forest mortality caused by pest insect outbreaks. We used window traps to study short-term changes in the abundance and community structure of saproxylic beetles following extensive mortality of mountain birch in sub-arctic northern Norway caused by an outbreak of geometrid moths. Three to five years after the outbreak, the proportion of obligate saproxylic individuals in the beetle community was roughly 10% higher in forest damaged by the outbreak than in undamaged forest. This was mainly due to two early-successional saproxylic beetle species. Facultative saproxylic beetles showed no consistent differences between damaged and undamaged forest. These findings would suggest a weak numerical response of the saproxylic beetle community to the dead wood left by the outbreak. We suggest that species-specific preferences for certain wood decay stages may limit the number of saproxylic species that respond numerically to an outbreak at a particular time, and that increases in responding species may be constrained by limitations to the amount of dead wood that can be exploited within a given timeframe (i.e. satiation effects). Low diversity of beetle species or slow development of larvae in our cold sub-arctic study region may also limit numerical responses. Our study suggests that saproxylic beetles, owing to weak numerical responses, may so far have played a minor role in decomposing the vast quantities of dead wood left by the moth outbreak.

Priority effects of early successional insects influence late successional fungi in dead wood.

PubMed

Jacobsen, Rannveig Margrete; Birkemoe, Tone; Sverdrup-Thygeson, Anne

2015-11-01

Community assembly is an integral process in all ecosystems, producing patterns of species distributions, biodiversity, and ecosystem functioning. Environmental filters and colonization history govern the assembly process, but their relative importance varies depending on the study system. Dead wood decomposition is a slow process, allowing decomposer communities to develop within a slowly changing substrate for decades. Despite this, there are few long-term studies of priority effects from colonization history in this ecosystem. In this study, we investigate the importance of insects in early succession of dead wood on the fungal community present one decade later. Sixty aspen trees were killed in two study landscapes, each tree producing one aspen high stump and log. Insects were sampled with flight interception traps during the first 4 years after tree death, and fungal fruiting bodies were registered in year twelve. We found positive priority effects of two fungivorous beetles, the sap beetle Glischrochilus quadripunctatus and the round fungus beetle Agathidium nigripenne, on the Artist's bracket (Ganoderma applanatum) and a positive priority effect of wood-boring beetles on the ascomycete Yellow fairy cup (Bisporella citrina). The Aspen bracket (Phellinus tremulae) did not respond to insects in early succession of the dead wood. Our results suggest that early successional insects can have significant, long-lasting effects on the late successional fungal community in dead wood. Also, the effect can be specific, with one fungus species depending on one or a few fungivorous beetle species. This has implications for decomposition and biodiversity in dead wood, as loss of early colonizing beetles may also affect the successional pathways they seem to initiate.

Formation of Circumbinary Planets in a Dead Zone

NASA Astrophysics Data System (ADS)

Martin, Rebecca G.; Armitage, Philip J.; Alexander, Richard D.

2013-08-01

Circumbinary planets have been observed at orbital radii where binary perturbations may have significant effects on the gas disk structure, on planetesimal velocity dispersion, and on the coupling between turbulence and planetesimals. Here, we note that the impact of all of these effects on planet formation is qualitatively altered if the circumbinary disk structure is layered, with a non-turbulent midplane layer (dead zone) and strongly turbulent surface layers. For close binaries, we find that the dead zone typically extends from a radius close to the inner disk edge up to a radius of around 10-20 AU from the center of mass of the binary. The peak in the surface density occurs within the dead zone, far from the inner disk edge, close to the snow line, and may act as a trap for aerodynamically coupled solids. We suggest that circumbinary planet formation may be easier near this preferential location than for disks around single stars. However, dead zones around wide binaries are less likely, and hence planet formation may be more difficult there.

Water Quality Modeling in the Dead End Sections of Drinking Water Distribution Networks

EPA Science Inventory

Dead-end sections of drinking water distribution networks are known to be problematic zones in terms of water quality degradation. Extended residence time due to water stagnation leads to rapid reduction of disinfectant residuals allowing the regrowth of microbial pathogens. Wate...

Effect of dead space on breathing stability at exercise in hypoxia.

PubMed

Hermand, Eric; Lhuissier, François J; Richalet, Jean-Paul

2017-12-01

Recent studies have shown that normal subjects exhibit periodic breathing when submitted to concomitant environmental (hypoxia) and physiological (exercise) stresses. A mathematical model including mass balance equations confirmed the short period of ventilatory oscillations and pointed out an important role of dead space in the genesis of these phenomena. Ten healthy subjects performed mild exercise on a cycloergometer in different conditions: rest/exercise, normoxia/hypoxia and no added dead space/added dead space (aDS). Ventilatory oscillations (V˙E peak power) were augmented by exercise, hypoxia and aDS (P<0.001, P<0.001 and P<0.01, respectively) whereas V˙E period was only shortened by exercise (P<0.001), with an 11-s period. aDS also increased V˙E (P<0.001), tidal volume (VT, P<0.001), and slightly augmented PETCO 2 (P<0.05) and the respiratory frequency (P<0.05). These results confirmed our previous model, showing an exacerbation of breathing instability by increasing dead space. This underlines opposite effects observed in heart failure patients and normal subjects, in which added dead space drastically reduced periodic breathing and sleep apneas. It also points out that alveolar ventilation remains very close to metabolic needs and is not affected by an added dead space. Clinical Trial reg. n°: NCT02201875. Copyright © 2017 Elsevier B.V. All rights reserved.

Hydrodynamic and Aerodynamic Tests of a Family of Models of Seaplane Floats with Varying Angles of Dead Rise - N.A.C.A. Models 57-A, 57-B, and 57-C

NASA Technical Reports Server (NTRS)

Parkinson, John B; Olson, Roland E; House, Rufus O

1939-01-01

Three models of V-bottom floats for twin-float seaplanes (N.A.C.A. models 57-A, 57-B, and 57-C) having angles of dead rise of 20 degrees, 25 degrees, and thirty degrees, respectively, were tested in the N.A.C.A. tank and in the N.A.C.A. 7- by 10-foot wind tunnel. Within the range investigated, the effect of angle of dead rise on water resistance was found to be negligible at speeds up to and including the hump speed, and water resistance was found to increase with angle of dead rise at planing speeds. The height of the spray at the hump speed decreased with increase in angle of dead rise and the aerodynamic drag increased with dead rise. Lengthening the forebody of model 57-B decreased the water resistance and the spray at speeds below the hump speed. Spray strips provided an effective means for the control of spray with the straight V sections used in the series but considerably increased the aerodynamic drag. Charts for the determination of the water resistance and the static properties of the model with 25 degrees dead rise and for the aerodynamic drag of all the models are included for use in design.

Defect specific luminescence dead layers in CdS and CdSe

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

Rosenberg, R. A.

CdS and CdSe are often used in optoelectronic devices whose effectiveness is may be dictated by defects in the near surface region. Luminescence is one of the main tools for studying such defects. The energy dependence of the x-ray excited optical luminescence (XEOL) spectra of these materials enables the extraction of the depth dependence of the defect distribution. Normal and time-gated XEOL spectra were obtained from these materials in the energy range 600 to 1500 eV. Here, we find that the results can best be understood in terms of a luminescence dead layer whose width depends on the position ofmore » the defect level in the band gap.« less

Defect specific luminescence dead layers in CdS and CdSe

DOE PAGES

Rosenberg, R. A.

2017-04-28

CdS and CdSe are often used in optoelectronic devices whose effectiveness is may be dictated by defects in the near surface region. Luminescence is one of the main tools for studying such defects. The energy dependence of the x-ray excited optical luminescence (XEOL) spectra of these materials enables the extraction of the depth dependence of the defect distribution. Normal and time-gated XEOL spectra were obtained from these materials in the energy range 600 to 1500 eV. Here, we find that the results can best be understood in terms of a luminescence dead layer whose width depends on the position ofmore » the defect level in the band gap.« less

Rigor mortis in an unusual position: Forensic considerations.

PubMed

D'Souza, Deepak H; Harish, S; Rajesh, M; Kiran, J

2011-07-01

We report a case in which the dead body was found with rigor mortis in an unusual position. The dead body was lying on its back with limbs raised, defying gravity. Direction of the salivary stains on the face was also defying the gravity. We opined that the scene of occurrence of crime is unlikely to be the final place where the dead body was found. The clues were revealing a homicidal offence and an attempt to destroy the evidence. The forensic use of 'rigor mortis in an unusual position' is in furthering the investigations, and the scientific confirmation of two facts - the scene of death (occurrence) is different from the scene of disposal of dead body, and time gap between the two places.

Rigor mortis in an unusual position: Forensic considerations

PubMed Central

D’Souza, Deepak H; Harish, S; Rajesh, M.; Kiran, J

2011-01-01

We report a case in which the dead body was found with rigor mortis in an unusual position. The dead body was lying on its back with limbs raised, defying gravity. Direction of the salivary stains on the face was also defying the gravity. We opined that the scene of occurrence of crime is unlikely to be the final place where the dead body was found. The clues were revealing a homicidal offence and an attempt to destroy the evidence. The forensic use of ‘rigor mortis in an unusual position’ is in furthering the investigations, and the scientific confirmation of two facts - the scene of death (occurrence) is different from the scene of disposal of dead body, and time gap between the two places. PMID:23776792

Tank tests of three models of flying-boat hulls of the pointed-step type with different angles of dead rise - NACA model 35 series

NASA Technical Reports Server (NTRS)

Dawson, John R

1936-01-01

The results of tank tests of three models of flying-boat hulls of the pointed-step type with different angles of dead rise are given in charts and are compared with results from tests of more conventional hulls. Increasing the angle of dead rise from 15 to 25 degrees: had little effect on the hump resistance; increased the resistance throughout the planning range; increased the best trim angle; reduced the maximum positive trimming moment required to obtain best trim angle; and had but a slight effect on the spray characteristics. For approximately the same angles of dead rise the resistance of the pointed-step hulls were considerably lower at high speeds than those of the more conventional hulls.

Local oscillator induced degradation of medium-term stability in passive atomic frequency standards

NASA Technical Reports Server (NTRS)

Dick, G. John; Prestage, John D.; Greenhall, Charles A.; Maleki, Lute

1990-01-01

As the performance of passive atomic frequency standards improves, a new limitation is encountered due to frequency fluctuations in an ancillary local oscillator (L.O.). The effect is due to time variation in the gain of the feedback which compensates L.O. frequency fluctuations. The high performance promised by new microwave and optical trapped ion standards may be severely compromised by this effect. Researchers present an analysis of this performance limitation for the case of sequentially interrogated standards. The time dependence of the sensitivity of the interrogation process to L.O. frequency fluctuations is evaluated for single-pulse and double-pulse Ramsey RF interrogation and for amplitude modulated pulses. The effect of these various time dependencies on performance of the standard is calculated for an L.O. with frequency fluctuations showing a typical 1/f spectral density. A limiting 1/sq. root gamma dependent deviation of frequency fluctuations is calculated as a function of pulse lengths, dead time, and pulse overlap. Researchers also present conceptual and hardware-oriented solutions to this problem which achieve a much more nearly constant sensitivity to L.O. fluctuations. Solutions involve use of double-pulse interrogation; alternate interrogation of multiple traps so that the dead time of one trap can be covered by operation of the other; and the use of double-pulse interrogation for two traps, so that during the time of the RF pulses, the increasing sensitivity of one trap tends to compensate for the decreasing sensitivity of the other. A solution making use of amplified-modulated pulses is also presented which shows nominally zero time variation.

Water Quality Modeling in the Dead End Sections of Drinking Water Distribution Networks -journal article

EPA Science Inventory

Dead-end sections of drinking water distribution networks are known to be problematic zones in terms of water quality degradation. Extended residence time due to water stagnation leads to rapid reduction of disinfectant residuals allowing the regrowth of microbial pathogens. Wate...

Adaptive neural network output feedback control for stochastic nonlinear systems with unknown dead-zone and unmodeled dynamics.

PubMed

Tong, Shaocheng; Wang, Tong; Li, Yongming; Zhang, Huaguang

2014-06-01

This paper discusses the problem of adaptive neural network output feedback control for a class of stochastic nonlinear strict-feedback systems. The concerned systems have certain characteristics, such as unknown nonlinear uncertainties, unknown dead-zones, unmodeled dynamics and without the direct measurements of state variables. In this paper, the neural networks (NNs) are employed to approximate the unknown nonlinear uncertainties, and then by representing the dead-zone as a time-varying system with a bounded disturbance. An NN state observer is designed to estimate the unmeasured states. Based on both backstepping design technique and a stochastic small-gain theorem, a robust adaptive NN output feedback control scheme is developed. It is proved that all the variables involved in the closed-loop system are input-state-practically stable in probability, and also have robustness to the unmodeled dynamics. Meanwhile, the observer errors and the output of the system can be regulated to a small neighborhood of the origin by selecting appropriate design parameters. Simulation examples are also provided to illustrate the effectiveness of the proposed approach.

Predicting live and dead tree basal area of bark beetle affected forests from discrete-return lidar

Treesearch

Benjamin C. Bright; Andrew T. Hudak; Robert McGaughey; Hans-Erik Andersen; Jose Negron

2013-01-01

Bark beetle outbreaks have killed large numbers of trees across North America in recent years. Lidar remote sensing can be used to effectively estimate forest biomass, but prediction of both live and dead standing biomass in beetle-affected forests using lidar alone has not been demonstrated. We developed Random Forest (RF) models predicting total, live, dead, and...

Theory of precipitation effects on dead cylindrical fuels

Treesearch

Michael A. Fosberg

1972-01-01

Numerical and analytical solutions of the Fickian diffusion equation were used to determine the effects of precipitation on dead cylindrical forest fuels. The analytical solution provided a physical framework. The numerical solutions were then used to refine the analytical solution through a similarity argument. The theoretical solutions predicted realistic rates of...

Online Robot Dead Reckoning Localization Using Maximum Relative Entropy Optimization With Model Constraints

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

Urniezius, Renaldas

2011-03-14

The principle of Maximum relative Entropy optimization was analyzed for dead reckoning localization of a rigid body when observation data of two attached accelerometers was collected. Model constraints were derived from the relationships between the sensors. The experiment's results confirmed that accelerometers each axis' noise can be successfully filtered utilizing dependency between channels and the dependency between time series data. Dependency between channels was used for a priori calculation, and a posteriori distribution was derived utilizing dependency between time series data. There was revisited data of autocalibration experiment by removing the initial assumption that instantaneous rotation axis of a rigidmore » body was known. Performance results confirmed that such an approach could be used for online dead reckoning localization.« less

Airborne laser scanning based quantification of dead-ice melting in recently deglaciated terrain

NASA Astrophysics Data System (ADS)

Klug, C.; Sailer, R.; Schümberg, M.; Stötter, J.

2012-04-01

Dead-ice is explained as stagnant glacial ice, not influenced by glacier flow anymore. Whenever glaciers have negative mass balances and an accumulation of debris-cover on the surface, dead-ice may form. Although, there are numerous conceptual process-sediment-landform models for the melt-out of dead-ice bodies and areas of dead-ice environments at glacier margins are easily accessible, just a few quantitative studies of dead-ice melting have been carried out so far. Processes and rates of dead-ice melting are commonly believed to be controlled by climate and debris-cover properties, but there is still a lack of knowledge about this fact. This study has a focus on the quantification of process induced volumetric changes caused by dead-ice melting. The research for this project was conducted at Hintereisferner (Ötztal Alps, Austria), Gepatschferner (Ötztal Alps, Austria) and Schrankar (Stubai Alps, Austria), areas for which a good data basis of ALS (Airborne Laser Scanning) measurements is available. 'Hintereisferner' can be characterized as a typical high alpine environment in mid-latitudes, which ranges between approximately 2250 m and 3740 m a.s.l.. The Hintereisferner region has been investigated intensively since many decades. Two dead ice bodies at the orographic right side and one at the orographic left side of the Hintereisferner glacier terminus (approx. at 2500 m to 2550 m a.s.l.) were identified. Since 2001, ALS measurements have been carried out regularly at Hintereisferner resulting in a unique data record of 21 ALS flight campaigns, allowing long-term explorations of the two dead-ice areas. The second study area of 'Gepatschferner' in the Kaunertal ranges between 2060 m and 3520 m a.s.l. and is the second largest glacier of Austria. Near the glacier tongue at the orographic right side a significant dead ice body has formed. The ALS data used for quantification include a period of time of 4 years (2006 - 2010). 'Schrankar' is located in the Western Stubai Alps in a north to south aligned valley, with 12 rockglaciers of different activities between elevations of 2400 m and 2800 m a.s.l.. Beside the rockglaciers, a big dead ice body (approx. at 2800 m to 2850 m a.s.l.) next to the terminus of the southern Schrankarferner was identified. For the quantification of dead-ice melting, ALS data was used from 2006 - 2009. Additionally, a time series of digital elevation models (DEM) derived from aerial images of different periods (1953 -2003) were integrated in the analysis. In recent years, high-accuracy DEMs from ALS altimetry are emerging as an additional data source to existing field measurements. We present inter annual and annual trends of topographic changes caused by dead-ice melting. These trends are determined from multitemporal DEM differencing. The DEMs are generated from aerial images and ALS data. First results on the three dead-ice bodies of Hintereisferner show significant changes (-0.48 m and -2.24 m respectively per year). The derived melt rates are discussed, summarized and assessed in relation to climate parameters, like mean annual air temperature, mean summer air temperature, mean annual precipitation, mean summer precipitation, and annual sum of positive degree days.

The dead donor rule: effect on the virtuous practice of medicine.

PubMed

Chaten, Frank C

2014-07-01

The President's Council on Bioethics in 2008 reaffirmed the necessity of the dead donor rule and the legitimacy of the current criteria for diagnosing both neurological and cardiac death. In spite of this report,many have continued to express concerns about the ethics of donation after circulatory death, the validity of determining death using neurological criteria and the necessity for maintaining the dead donor rule for organ donation. I analysed the dead donor rule for its effect on the virtuous practice of medicine by physicians caring for potential organ donors. The dead donor rule consistently impedes physicians in fulfilling their primary duty to act for the good of their prospective donor patients. This compromises the virtue of fidelity. It also weakens many other virtues necessary for physicians to provide excellent end-of-life care. The dead donor rule, while ethically powerful in theory, loses its force during translation to the bedside. This is so because the rule mandates simultaneous life and death within the same body for organ donation, a biological status that is inherently contradictory. The rule should be rejected as an ethical norm governing vital organ transplantation at the end of life. Its elimination will strengthen the doctor–patient relationship and foster trustworthiness in organ procurement.

Literary Genres in Poetic Texts from the Dead Sea Scrolls

ERIC Educational Resources Information Center

Pickut, William Douglas

2017-01-01

Among the texts of the Dead Sea Scrolls, there are four literary compositions that bear the superscriptional designations shir and mizmor. These designations correspond directly to superscriptional designations provided many times in both the now-canonical Psalter and the various witnesses to those texts unearthed at Qumran. On its face, this fact…

ON HYDRODYNAMIC MOTIONS IN DEAD ZONES

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

Oishi, Jeffrey S.; Mac Low, Mordecai-Mark, E-mail: jsoishi@astro.berkeley.ed, E-mail: mordecai@amnh.or

We investigate fluid motions near the midplane of vertically stratified accretion disks with highly resistive midplanes. In such disks, the magnetorotational instability drives turbulence in thin layers surrounding a resistive, stable dead zone. The turbulent layers in turn drive motions in the dead zone. We examine the properties of these motions using three-dimensional, stratified, local, shearing-box, non-ideal, magnetohydrodynamical simulations. Although the turbulence in the active zones provides a source of vorticity to the midplane, no evidence for coherent vortices is found in our simulations. It appears that this is because of strong vertical oscillations in the dead zone. By analyzingmore » time series of azimuthally averaged flow quantities, we identify an axisymmetric wave mode particular to models with dead zones. This mode is reduced in amplitude, but not suppressed entirely, by changing the equation of state from isothermal to ideal. These waves are too low frequency to affect sedimentation of dust to the midplane, but may have significance for the gravitational stability of the resulting midplane dust layers.« less

Thermodynamic and fluid mechanic analysis of rapid pressurization in a dead-end tube

NASA Technical Reports Server (NTRS)

Leslie, Ian H.

1989-01-01

Three models have been applied to very rapid compression of oxygen in a dead-ended tube. Pressures as high as 41 MPa (6000 psi) leading to peak temperatures of 1400 K are predicted. These temperatures are well in excess of the autoignition temperature (750 K) of teflon, a frequently used material for lining hoses employed in oxygen service. These findings are in accord with experiments that have resulted in ignition and combustion of the teflon, leading to the combustion of the stainless steel braiding and catastrophic failure. The system analyzed was representative of a capped off-high-pressure oxygen line, which could be part of a larger system. Pressurization of the larger system would lead to compression in the dead-end line, and possible ignition of the teflon liner. The model consists of a large plenum containing oxygen at the desired pressure (500 to 6000 psi). The plenum is connected via a fast acting valve to a stainless steel tube 2 cm inside diameter. Opening times are on the order of 15 ms. Downstream of the valve is an orifice sized to increase filling times to around 100 ms. The total length from the valve to the dead-end is 150 cm. The distance from the valve to the orifice is 95 cm. The models describe the fluid mechanics and thermodynamics of the flow, and do not include any combustion phenomena. A purely thermodynamic model assumes filling to be complete upstream of the orifice before any gas passes through the orifice. This simplification is reasonable based on experiment and computer modeling. Results show that peak temperatures as high as 4800 K can result from recompression of the gas after expanding through the orifice. An approximate transient model without an orifice was developed assuming an isentropic compression process. An analytical solution was obtained. Results indicated that fill times can be considerably shorter than valve opening times. The third model was a finite difference, 1-D transient compressible flow model. Results from the code show the recompression effect but predict much lower peak temperatures than the thermodynamic model.

Thermodynamic and fluid mechanic analysis of rapid pressurization in a dead-end tube

NASA Astrophysics Data System (ADS)

Leslie, Ian H.

1989-12-01

Three models have been applied to very rapid compression of oxygen in a dead-ended tube. Pressures as high as 41 MPa (6000 psi) leading to peak temperatures of 1400 K are predicted. These temperatures are well in excess of the autoignition temperature (750 K) of teflon, a frequently used material for lining hoses employed in oxygen service. These findings are in accord with experiments that have resulted in ignition and combustion of the teflon, leading to the combustion of the stainless steel braiding and catastrophic failure. The system analyzed was representative of a capped off-high-pressure oxygen line, which could be part of a larger system. Pressurization of the larger system would lead to compression in the dead-end line, and possible ignition of the teflon liner. The model consists of a large plenum containing oxygen at the desired pressure (500 to 6000 psi). The plenum is connected via a fast acting valve to a stainless steel tube 2 cm inside diameter. Opening times are on the order of 15 ms. Downstream of the valve is an orifice sized to increase filling times to around 100 ms. The total length from the valve to the dead-end is 150 cm. The distance from the valve to the orifice is 95 cm. The models describe the fluid mechanics and thermodynamics of the flow, and do not include any combustion phenomena. A purely thermodynamic model assumes filling to be complete upstream of the orifice before any gas passes through the orifice. This simplification is reasonable based on experiment and computer modeling. Results show that peak temperatures as high as 4800 K can result from recompression of the gas after expanding through the orifice. An approximate transient model without an orifice was developed assuming an isentropic compression process. An analytical solution was obtained.

Coarse woody debris and soil respiration 6 years post-tornado in a Piedmont forest blowdown

NASA Astrophysics Data System (ADS)

Oldfield, C.; Peterson, C. J.

2017-12-01

Severe wind disturbances can rapidly change carbon pools and fluxes in forests, causing a site to switch from a carbon sink to a source in a matter of minutes. Moreover, salvage logging after a disturbance can result in disturbed and compacted soil, altered woody debris carbon pools, and seedling mortality, all of which may further alter carbon dynamics beyond that caused by the disturbance itself. We measured down dead wood and soil respiration in the summer of 2017 at Boggs Creek Recreation Area in the Piedmont of northeast Georgia, the site of a severe tornado in 2011. Down dead wood and soil respiration were compared in control (intact forest), salvaged, and unsalvaged areas. Megagrams per hectare of down dead wood was significantly higher in the unsalvaged condition than the control or salvage logging condition (ANOVAs, p<0.05 in both cases). Conversely, the volume of down dead wood was not significantly different in the control when compared to the salvage logging condition (p=0.99). Soil respiration was significantly higher in the salvage logged condition than the control (p<0.05), but was not significantly different between the unsalvaged condition and the control (p=0.30) or the unsalvaged condition and the salvaged condition (p=0.58). This research shows that wind disturbances have a lasting impact on the amount of down dead wood in a forest, and salvage logging may lead to greater soil respiration years after the initial disturbance, both of which will influence the time elapsed before a disturbed forest switches from carbon source to carbon sink. Further research is needed to determine the duration of these effects, along with the carbon consequences for other forest carbon pools.

The 'Soil Cover App' - a new tool for fast determination of dead and living biomass on soil

NASA Astrophysics Data System (ADS)

Bauer, Thomas; Strauss, Peter; Riegler-Nurscher, Peter; Prankl, Johann; Prankl, Heinrich

2017-04-01

Worldwide many agricultural practices aim on soil protection strategies using living or dead biomass as soil cover. Especially for the case when management practices are focusing on soil erosion mitigation the effectiveness of these practices is directly driven by the amount of soil coverleft on the soil surface. Hence there is a need for quick and reliable methods of soil cover estimation not only for living biomass but particularly for dead biomass (mulch). Available methods for the soil cover measurement are either subjective, depending on an educated guess or time consuming, e.g., if the image is analysed manually at grid points. We therefore developed a mobile application using an algorithm based on entangled forest classification. The final output of the algorithm gives classified labels for each pixel of the input image as well as the percentage of each class which are living biomass, dead biomass, stones and soil. Our training dataset consisted of more than 250 different images and their annotated class information. Images have been taken in a set of different environmental conditions such as light, soil coverages from between 0% to 100%, different materials such as living plants, residues, straw material and stones. We compared the results provided by our mobile application with a data set of 180 images that had been manually annotated A comparison between both methods revealed a regression slope of 0.964 with a coefficient of determination R2 = 0.92, corresponding to an average error of about 4%. While average error of living plant classification was about 3%, dead residue classification resulted in an 8% error. Thus the new mobile application tool offers a fast and easy way to obtain information on the protective potential of a particular agricultural management site.

Density-Dependent Recycling Promotes the Long-Term Survival of Bacterial Populations during Periods of Starvation.

PubMed

Takano, Sotaro; Pawlowska, Bogna J; Gudelj, Ivana; Yomo, Tetsuya; Tsuru, Saburo

2017-02-07

The amount of natural resources in the Earth's environment is in flux, which can trigger catastrophic collapses of ecosystems. How populations survive under nutrient-poor conditions is a central question in ecology. Curiously, some bacteria persist for a long time in nutrient-poor environments. Although this survival may be accomplished through cell death and the recycling of dead cells, the importance of these processes and the mechanisms underlying the survival of the populations have not been quantitated. Here, we use microbial laboratory experiments and mathematical models to demonstrate that death and recycling are essential activities for the maintenance of cell survival. We also show that the behavior of the survivors is governed by population density feedback, wherein growth is limited not only by the available resources but also by the population density. The numerical simulations suggest that population density-dependent recycling could be an advantageous behavior under starvation conditions. How organisms survive after exhaustion of resources is a central question in ecology. Starving Escherichia coli constitute a model system to understand survival mechanisms during long-term starvation. Although death and the recycling of dead cells might play a key role in the maintenance of long-term survival, their mechanisms and importance have not been quantitated. Here, we verified the significance of social recycling of dead cells for long-term survival. We also show that the survivors restrained their recycling and did not use all available nutrients released from dead cells, which may be advantageous under starvation conditions. These results indicate that not only the utilization of dead cells but also restrained recycling coordinate the effective utilization of limited resources for long-term survival under starvation. Copyright © 2017 Takano et al.

Numerical Responses of Saproxylic Beetles to Rapid Increases in Dead Wood Availability following Geometrid Moth Outbreaks in Sub-Arctic Mountain Birch Forest

PubMed Central

Vindstad, Ole Petter Laksforsmo; Schultze, Sabrina; Jepsen, Jane Uhd; Biuw, Martin; Kapari, Lauri; Sverdrup-Thygeson, Anne; Ims, Rolf Anker

2014-01-01

Saproxylic insects play an important part in decomposing dead wood in healthy forest ecosystems, but little is known about their role in the aftermath of large-scale forest mortality caused by pest insect outbreaks. We used window traps to study short-term changes in the abundance and community structure of saproxylic beetles following extensive mortality of mountain birch in sub-arctic northern Norway caused by an outbreak of geometrid moths. Three to five years after the outbreak, the proportion of obligate saproxylic individuals in the beetle community was roughly 10% higher in forest damaged by the outbreak than in undamaged forest. This was mainly due to two early-successional saproxylic beetle species. Facultative saproxylic beetles showed no consistent differences between damaged and undamaged forest. These findings would suggest a weak numerical response of the saproxylic beetle community to the dead wood left by the outbreak. We suggest that species-specific preferences for certain wood decay stages may limit the number of saproxylic species that respond numerically to an outbreak at a particular time, and that increases in responding species may be constrained by limitations to the amount of dead wood that can be exploited within a given timeframe (i.e. satiation effects). Low diversity of beetle species or slow development of larvae in our cold sub-arctic study region may also limit numerical responses. Our study suggests that saproxylic beetles, owing to weak numerical responses, may so far have played a minor role in decomposing the vast quantities of dead wood left by the moth outbreak. PMID:24911056

Dead Sea drawdown and monsoonal impacts in the Levant during the last interglacial

NASA Astrophysics Data System (ADS)

Torfstein, Adi; Goldstein, Steven L.; Kushnir, Yochanan; Enzel, Yehouda; Haug, Gerald; Stein, Mordechai

2015-02-01

Sediment cores recovered by the Dead Sea Deep Drilling Project (DSDDP) from the deepest basin of the hypersaline, terminal Dead Sea (lake floor at ∼725 m below mean sea level) reveal the detailed climate history of the lake's watershed during the last interglacial period (Marine Isotope Stage 5; MIS5). The results document both a more intense aridity during MIS5 than during the Holocene, and the moderating impacts derived from the intense MIS5e African Monsoon. Early MIS5e (∼133-128 ka) was dominated by hyperarid conditions in the Eastern Mediterranean-Levant, indicated by thick halite deposition triggered by a lake-level drop. Halite deposition was interrupted however, during the MIS5e peak (∼128-122 ka) by sequences of flood deposits, which are coeval with the timing of the intense precession-forced African monsoon that generated Mediterranean sapropel S5. A subsequent weakening of this humidity source triggered extreme aridity in the Dead Sea watershed and resulting in the biggest known lake level drawdown in its history, reflected by the deposition of thick salt layers, and a capping pebble layer corresponding to a hiatus at ∼116-110 ka. The DSDDP core provides the first evidence for a direct association of the African monsoon with mid subtropical latitude climate systems effecting the Dead Sea watershed. Combined with coeval deposition of Arabia and southern Negev speleothems, Arava travertines, and calcification of Red Sea corals, the evidence points to a climatically wet corridor that could have facilitated homo sapiens migration "out of Africa" during the MIS5e peak. The hyperaridity documented during MIS5e may provide an important analogue for future warming of arid regions of the Eastern Mediterranean-Levant.

FORMATION OF CIRCUMBINARY PLANETS IN A DEAD ZONE

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

Martin, Rebecca G.; Armitage, Philip J.; Alexander, Richard D.

Circumbinary planets have been observed at orbital radii where binary perturbations may have significant effects on the gas disk structure, on planetesimal velocity dispersion, and on the coupling between turbulence and planetesimals. Here, we note that the impact of all of these effects on planet formation is qualitatively altered if the circumbinary disk structure is layered, with a non-turbulent midplane layer (dead zone) and strongly turbulent surface layers. For close binaries, we find that the dead zone typically extends from a radius close to the inner disk edge up to a radius of around 10-20 AU from the center ofmore » mass of the binary. The peak in the surface density occurs within the dead zone, far from the inner disk edge, close to the snow line, and may act as a trap for aerodynamically coupled solids. We suggest that circumbinary planet formation may be easier near this preferential location than for disks around single stars. However, dead zones around wide binaries are less likely, and hence planet formation may be more difficult there.« less

The Dead Donor Rule: Can It Withstand Critical Scrutiny?

PubMed Central

Miller, Franklin G.; Truog, Robert D.; Brock, Dan W.

2010-01-01

Transplantation of vital organs has been premised ethically and legally on “the dead donor rule” (DDR)—the requirement that donors are determined to be dead before these organs are procured. Nevertheless, scholars have argued cogently that donors of vital organs, including those diagnosed as “brain dead” and those declared dead according to cardiopulmonary criteria, are not in fact dead at the time that vital organs are being procured. In this article, we challenge the normative rationale for the DDR by rejecting the underlying premise that it is necessarily wrong for physicians to cause the death of patients and the claim that abandoning this rule would exploit vulnerable patients. We contend that it is ethical to procure vital organs from living patients sustained on life support prior to treatment withdrawal, provided that there is valid consent for both withdrawing treatment and organ donation. However, the conservatism of medical ethics and practical concerns make it doubtful that the DDR will be abandoned in the near future. This leaves the current practice of organ transplantation based on the “moral fiction” that donors are dead when vital organs are procured. PMID:20439355

Persistence of bacterial DNA in orthopedic infections.

PubMed

Kaplan, Heidi B; Miranda, Justin A; Gogola, Gloria R; Gomez, Karen; Ambrose, Catherine G

2018-06-01

Polymerase chain reaction (PCR) has been proposed as a method to identify bacteria in clinical samples because it is more sensitive than culture techniques and can produce results rapidly. However, PCR can detect DNA from dead cells and thus cannot distinguish between live and dead cells in a tissue sample. Killed Staphylococcus aureus cells were implanted into the femurs and knee joints of rats to determine the length of time that DNA from dead cells is detectable in a living animal under conditions similar to common orthopedic infections. In the joint infection model studied here, the DNA from the dead planktonic bacteria was detected using PCR immediately after injection or 24 h later, but was undetectable 48 and 72 h after injection. In the biofilm implanted-device model studied, the DNA from these dead biofilm cells was detected by PCR immediately after implantation and at 24 h, but not at 48 or 72 h. Thus, our results indicate that DNA from dead cells does not persist in these animal model systems for more than 2 days, which should reduce concerns about possible false positive results using molecular DNA-based techniques for the detection of pathogens. Copyright © 2018. Published by Elsevier Inc.

Texture-based measurement of spatial frequency response using the dead leaves target: extensions, and application to real camera systems

NASA Astrophysics Data System (ADS)

McElvain, Jon; Campbell, Scott P.; Miller, Jonathan; Jin, Elaine W.

2010-01-01

The dead leaves model was recently introduced as a method for measuring the spatial frequency response (SFR) of camera systems. The target consists of a series of overlapping opaque circles with a uniform gray level distribution and radii distributed as r-3. Unlike the traditional knife-edge target, the SFR derived from the dead leaves target will be penalized for systems that employ aggressive noise reduction. Initial studies have shown that the dead leaves SFR correlates well with sharpness/texture blur preference, and thus the target can potentially be used as a surrogate for more expensive subjective image quality evaluations. In this paper, the dead leaves target is analyzed for measurement of camera system spatial frequency response. It was determined that the power spectral density (PSD) of the ideal dead leaves target does not exhibit simple power law dependence, and scale invariance is only loosely obeyed. An extension to the ideal dead leaves PSD model is proposed, including a correction term to account for system noise. With this extended model, the SFR of several camera systems with a variety of formats was measured, ranging from 3 to 10 megapixels; the effects of handshake motion blur are also analyzed via the dead leaves target.

A DEAD-box RNA helicase promotes thermodynamic equilibration of kinetically trapped RNA structures in vivo.

PubMed

Ruminski, Dana J; Watson, Peter Y; Mahen, Elisabeth M; Fedor, Martha J

2016-03-01

RNAs must assemble into specific structures in order to carry out their biological functions, but in vitro RNA folding reactions produce multiple misfolded structures that fail to exchange with functional structures on biological time scales. We used carefully designed self-cleaving mRNAs that assemble through well-defined folding pathways to identify factors that differentiate intracellular and in vitro folding reactions. Our previous work showed that simple base-paired RNA helices form and dissociate with the same rate and equilibrium constants in vivo and in vitro. However, exchange between adjacent secondary structures occurs much faster in vivo, enabling RNAs to quickly adopt structures with the lowest free energy. We have now used this approach to probe the effects of an extensively characterized DEAD-box RNA helicase, Mss116p, on a series of well-defined RNA folding steps in yeast. Mss116p overexpression had no detectable effect on helix formation or dissociation kinetics or on the stability of interdomain tertiary interactions, consistent with previous evidence that intracellular factors do not affect these folding parameters. However, Mss116p overexpression did accelerate exchange between adjacent helices. The nonprocessive nature of RNA duplex unwinding by DEAD-box RNA helicases is consistent with a branch migration mechanism in which Mss116p lowers barriers to exchange between otherwise stable helices by the melting and annealing of one or two base pairs at interhelical junctions. These results suggest that the helicase activity of DEAD-box proteins like Mss116p distinguish intracellular RNA folding pathways from nonproductive RNA folding reactions in vitro and allow RNA structures to overcome kinetic barriers to thermodynamic equilibration in vivo. © 2016 Ruminski et al.; Published by Cold Spring Harbor Laboratory Press for the RNA Society.

Nebular dead zone effects on the D/H ratio in chondrites and comets

NASA Astrophysics Data System (ADS)

Ali-Dib, Mohamad; Martin, R. G.; Petit, J.-M.; Mousis, O.; Vernazza, P.; Lunine, J. I.

2015-11-01

Comets and chondrites show non-monotonic behaviour of their Deuterium to Hydrogen (D/H) ratio as a function of their formation location from the Sun. This is difficult to explain with a classical protoplanetary disk model that has a decreasing temperature structure with radius from the Sun.We want to understand if a protoplanetary disc with a dead zone, a region of zero or low turbulence, can explain the measured D/H values in comets and chondrites. We use time snapshots of a vertically layered disk model with turbulent surface layers and a dead zone at the midplane. The disc has a non-monotonic temperature structure due to increased heating from self-gravity in the outer parts of the dead zone. We couple this to a D/H ratio evolution model in order to quantify the effect of such thermal profiles on D/H enrichment in the nebula.We find that the local temperature peak in the disk can explain the diversity in the D/H ratios of different chondritic families. This disk temperature profile leads to a non-monotonic D/H enrichment evolution, allowing these families to acquire their different D/H values while forming in close proximity. The formation order we infer for these families is compatible with that inferred from their water abundances. However, we find that even for very young disks, the thermal profile reversal is too close to the Sun to be relevant for comets.[1] Ali-Dib, M., Martin, R. G., Petit, J.-M., Mousis, O., Vernazza, P., and Lunine, J. I. (2015, in press A&A). arXiv:1508.00263.

Biosorption of nickel by Lysinibacillus sp. BA2 native to bauxite mine.

PubMed

Prithviraj, Desale; Deboleena, Kashyap; Neelu, Nawani; Noor, Nahar; Aminur, Rahman; Balasaheb, Kapadnis; Abul, Mandal

2014-09-01

The current scenario of environmental pollution urges the need for an effective solution for toxic heavy metal removal from industrial wastewater. Bioremediation is the most cost effective process employed by the use of microbes especially bacteria resistant to toxic metals. In this study, Lysinibacillus sp. BA2, a nickel tolerant strain isolated from bauxite mine was used for the biosorption of Ni(II). Lysinibacillus sp. BA2 biomass had isoelectric point (pI) of 3.3. The maximum negative zeta potential value (-39.45) was obtained at pH 6.0 which was highly favourable for Ni(II) biosorption. 238.04mg of Ni(II) adsorbed on one gram of dead biomass and 196.32mg adsorbed on one gram of live biomass. The adsorption of Ni(II) on biomass increased with time and attained saturation after 180min with rapid biosorption in initial 30min. The Langmuir and Freundlich isotherms could fit well for biosorption of Ni(II) by dead biomass while Langmuir isotherm provided a better fit for live biomass based on correlation coefficient values. The kinetic studies of Ni(II) removal, using dead and live biomass was well explained by second-order kinetic model. Ni(II) adsorption on live biomass was confirmed by SEM-EDX where cell aggregation and increasing irregularity of cell morphology was observed even though cells were in non-growing state. The FTIR analysis of biomass revealed the presence of carboxyl, hydroxyl and amino groups, which seem responsible for biosorption of Ni(II). The beads made using dead biomass of Lysinibacillus sp. BA2 could efficiently remove Ni(II) from effluent solutions. These microbial cells can substitute expensive methods for treating nickel contaminated industrial wastewaters. Copyright © 2014 Elsevier Inc. All rights reserved.

When a tree falls: Controls on wood decay predict standing dead tree fall and new risks in changing forests.

PubMed

Oberle, Brad; Ogle, Kiona; Zanne, Amy E; Woodall, Christopher W

2018-01-01

When standing dead trees (snags) fall, they have major impacts on forest ecosystems. Snag fall can redistribute wildlife habitat and impact public safety, while governing important carbon (C) cycle consequences of tree mortality because ground contact accelerates C emissions during deadwood decay. Managing the consequences of altered snag dynamics in changing forests requires predicting when snags fall as wood decay erodes mechanical resistance to breaking forces. Previous studies have pointed to common predictors, such as stem size, degree of decay and species identity, but few have assessed the relative strength of underlying mechanisms driving snag fall across biomes. Here, we analyze nearly 100,000 repeated snag observations from boreal to subtropical forests across the eastern United States to show that wood decay controls snag fall in ways that could generate previously unrecognized forest-climate feedback. Warmer locations where wood decays quickly had much faster rates of snag fall. The effect of temperature on snag fall was so strong that in a simple forest C model, anticipated warming by mid-century reduced snag C by 22%. Furthermore, species-level differences in wood decay resistance (durability) accurately predicted the timing of snag fall. Differences in half-life for standing dead trees were similar to expected differences in the service lifetimes of wooden structures built from their timber. Strong effects of temperature and wood durability imply future forests where dying trees fall and decay faster than at present, reducing terrestrial C storage and snag-dependent wildlife habitat. These results can improve the representation of forest C cycling and assist forest managers by helping predict when a dead tree may fall.

When a tree falls: Controls on wood decay predict standing dead tree fall and new risks in changing forests

PubMed Central

Ogle, Kiona; Zanne, Amy E.; Woodall, Christopher W.

2018-01-01

When standing dead trees (snags) fall, they have major impacts on forest ecosystems. Snag fall can redistribute wildlife habitat and impact public safety, while governing important carbon (C) cycle consequences of tree mortality because ground contact accelerates C emissions during deadwood decay. Managing the consequences of altered snag dynamics in changing forests requires predicting when snags fall as wood decay erodes mechanical resistance to breaking forces. Previous studies have pointed to common predictors, such as stem size, degree of decay and species identity, but few have assessed the relative strength of underlying mechanisms driving snag fall across biomes. Here, we analyze nearly 100,000 repeated snag observations from boreal to subtropical forests across the eastern United States to show that wood decay controls snag fall in ways that could generate previously unrecognized forest-climate feedback. Warmer locations where wood decays quickly had much faster rates of snag fall. The effect of temperature on snag fall was so strong that in a simple forest C model, anticipated warming by mid-century reduced snag C by 22%. Furthermore, species-level differences in wood decay resistance (durability) accurately predicted the timing of snag fall. Differences in half-life for standing dead trees were similar to expected differences in the service lifetimes of wooden structures built from their timber. Strong effects of temperature and wood durability imply future forests where dying trees fall and decay faster than at present, reducing terrestrial C storage and snag-dependent wildlife habitat. These results can improve the representation of forest C cycling and assist forest managers by helping predict when a dead tree may fall. PMID:29742158

Responses of dead forest fuel moisture to climate change

Treesearch

Yongqiang Liu

2016-01-01

Forest fuel moisture is an important factor for wildland fire behavior. Predicting future wildfire trends and controlled burned conditions is essential to effective natural resource management, but the associated effects of forest fuel moisture remain uncertain. This study investigates the responses of dead forest fuel moisture to climate change in the...

The growth of deactivated layers on CsI(Na) scintillating crystals

NASA Technical Reports Server (NTRS)

Goodman, N. B.

1975-01-01

An effective and sensitive measurement of the depth of a deactivated or dead layer can be obtained from the relative attenuation of the 22.162 KeV and 87.9 KeV X-rays emitted by Cd 109. The alpha-particles emitted by Am 241 are also useful in measuring dead layers less than 25 microns. The properties and temporal development of dead layers are discussed in detail. The rate of growth of a deal layer is closely related to the ambient humidity, and the damage to the crystal is irreversible by any known process. The dead layer can be minimized by polishing all crystal surfaces and by keeping the crystal in a vacuum or a dry atmosphere. Since a dead layer seriously inhibits the response of a crystal to X-rays of energies below approximately 20 keV, CsI(Na) detectors should not be used at these energies unless precautions are taken to ensure that no dead layer forms.

The notochord curvature in medaka (Oryzias latipes) embryos as a response to ultraviolet A irradiation.

PubMed

Sayed, Alaa El-Din Hamid; Mitani, Hiroshi

2016-11-01

In the present work, the destructive effects of ultraviolet A (UVA; 366nm) irradiation on the developmental stages of Japanese medaka (Oryzias latipes) are revealed in terms of hatching success, mortality rate, and morphological malformations (yolk sac edema, body curvature, fin blistering, and dwarfism). Fertilized eggs in stage 4 were exposed to 15, 30, and 60min/day UVA for 3days in replicates. Fish were staged and aged following the stages established by Iwamatsu [1]. We observed and recorded the hatching time and deformed and dead embryos continuously. The hatching time was prolonged and the deformed and dead embryos numbers were increased by UVA dose increase. At stage 40, samples from each group were fixed to investigate their morphology and histopathology. Some morphological malformations were recorded after UVA exposure in both strains. Histopathological changes were represented as different shapes of curvature in notochord with collapse. The degree of collapsation was depended on the dose and time of UVA exposure. Our findings show that exposure to UVA irradiation caused less vertebral column curvature in medaka fry. Moreover, p53-deficient embryos were more tolerant than those of wild-type (Hd-rR) Japanese medaka. This study indicated the dangerous effects of the UVA on medaka. Copyright © 2016 Elsevier B.V. All rights reserved.

Molecular Probes: A Tool for Studying Toxicity of VOCs to P.Putida F1

NASA Astrophysics Data System (ADS)

Singh, R.; Olson, M. S.

2007-12-01

Volatile Organic Compounds (VOCs) are of great concern in ground water remediation, and are generally present in the form of NAPLs in subsurface environments. Among the various treatment technologies, in situ bioremediation is one of the most effective and low-cost treatment options. Many soil bacteria are reported to degrade these organic contaminants via metabolism (using them as a source of carbon to derive energy) or co- metabolism up to certain concentrations. However, larger concentrations of these contaminants are toxic to bacteria. Thus, in order to achieve successful bioremediation, it is important to determine the optimal concentrations of various contaminants that is beneficial for the activity and survival of degrading bacteria. The purpose of this study is to develop a novel method for toxicity analyses of VOC contaminants to the soil bacteria that degrade them. The present study is based on a two-color fluorescence assay of bacterial viability which facilitates actual counting of live and dead bacteria. Pseudomonas putida F1 cells were labeled with a LIVE/DEAD® BacLightTM bacterial viability kit (Invitrogen), which consists of a mixture of two dyes, SYTO 9 and propidium iodide, each with a different ability to penetrate healthy bacterial cells. Live cells stain green whereas propidium iodide (red dye) only penetrates cells with compromised membranes that are considered dead or dying. Stained cells were exposed to different concentrations of trichloroethylene (TCE) and toluene in sealed vials. Change in the concentrations of green and red cells were monitored over the time using fluorescence microscopy. UTHSCSA ImageTool software was used to count the live and dead cells in the images. It was observed that live (green) cell concentrations decreased and dead/damaged (red) cell concentrations increased over time when cells were exposed to TCE. No significant changes were observed in control experiments. Death rate constants calculated based on live cell disappearance and dead/damaged cell appearance were found to be approximately equal for TCE. Results will be presented in terms of dose response and death rate curves. Death rate constants and minimum inhibitory concentrations for survival of P. Putida F1 exposed to TCE and toluene will be compared.

The lead time tradeoff: the case of health states better than dead.

PubMed

Pinto-Prades, José Luis; Rodríguez-Míguez, Eva

2015-04-01

Lead time tradeoff (L-TTO) is a variant of the time tradeoff (TTO). L-TTO introduces a lead period in full health before illness onset, avoiding the need to use 2 different procedures for states better and worse than dead. To estimate utilities, additive separability is assumed. We tested to what extent violations of this assumption can bias utilities estimated with L-TTO. A sample of 500 members of the Spanish general population evaluated 24 health states, using face-to-face interviews. A total of 188 subjects were interviewed with L-TTO and the rest with TTO. Both samples evaluated the same set of 24 health states, divided into 4 groups with 6 health states per set. Each subject evaluated 1 of the sets. A random effects regression model was fitted to our data. Only health states better than dead were included in the regression since it is in this subset where additive separability can be tested clearly. Utilities were higher in L-TTO in relation to TTO (on average L-TTO adds about 0.2 points to the utility of health states), suggesting that additive separability is violated. The difference between methods increased with the severity of the health state. Thus, L-TTO adds about 0.14 points to the average utility of the less severe states, 0.23 to the intermediate states, and 0.28 points to the more severe estates. L-TTO produced higher utilities than TTO. Health problems are perceived as less severe if a lead period in full health is added upfront, implying that there are interactions between disjointed time periods. The advantages of this method have to be compared with the cost of modeling the interaction between periods. © The Author(s) 2014.

Application of propidium monoazide quantitative real-time PCR to quantify the viability of Lactobacillus delbrueckii ssp. bulgaricus.

PubMed

Shao, Yuyu; Wang, Zhaoxia; Bao, Qiuhua; Zhang, Heping

2016-12-01

In this study, a combination of propidium monoazide (PMA) and quantitative real-time PCR (qPCR) was used to develop a method to determine the viability of cells of Lactobacillus delbrueckii ssp. bulgaricus ND02 (L. bulgaricus) that may have entered into a viable but nonculturable state. This can happen due to its susceptibility to cold shock during lyophilization and storage. Propidium monoazide concentration, PMA incubation time, and light exposure time were optimized to fully exploit the PMA-qPCR approach to accurately assess the total number of living L. bulgaricus ND02. Although PMA has little influence on living cells, when concentrations of PMA were higher than 30μg/mL the number of PCR-positive living bacteria decreased from 10 6 to 10 5 cfu/mL in comparison with qPCR enumeration. Mixtures of living and dead cells were used as method verification samples for enumeration by PMA-qPCR, demonstrating that this method was feasible and effective for distinguishing living cells of L. bulgaricus when mixed with a known number of dead cells. We suggest that several conditions need to be studied further before PMA-qPCR methods can be accurately used to distinguish living from dead cells for enumeration under more realistic sampling situations. However, this research provides a rapid way to enumerate living cells of L. bulgaricus and could be used to optimize selection of cryoprotectants in the lyophilization process and develop technologies for high cell density cultivation and optimal freeze-drying processes. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Tectonic evolution of the Qumran Basin from high-resolution 3.5-kHz seismic profiles and its implication for the evolution of the northern Dead Sea Basin

NASA Astrophysics Data System (ADS)

Lubberts, Ronald K.; Ben-Avraham, Zvi

2002-02-01

The Dead Sea Basin is a morphotectonic depression along the Dead Sea Transform. Its structure can be described as a deep rhomb-graben (pull-apart) flanked by two block-faulted marginal zones. We have studied the recent tectonic structure of the northwestern margin of the Dead Sea Basin in the area where the northern strike-slip master fault enters the basin and approaches the western marginal zone (Western Boundary Fault). For this purpose, we have analyzed 3.5-kHz seismic reflection profiles obtained from the northwestern corner of the Dead Sea. The seismic profiles give insight into the recent tectonic deformation of the northwestern margin of the Dead Sea Basin. A series of 11 seismic profiles are presented and described. Although several deformation features can be explained in terms of gravity tectonics, it is suggested that the occurrence of strike-slip in this part of the Dead Sea Basin is most likely. Seismic sections reveal a narrow zone of intensely deformed strata. This zone gradually merges into a zone marked by a newly discovered tectonic depression, the Qumran Basin. It is speculated that both structural zones originate from strike-slip along right-bending faults that splay-off from the Jordan Fault, the strike-slip master fault that delimits the active Dead Sea rhomb-graben on the west. Fault interaction between the strike-slip master fault and the normal faults bounding the transform valley seems the most plausible explanation for the origin of the right-bending splays. We suggest that the observed southward widening of the Dead Sea Basin possibly results from the successive formation of secondary right-bending splays to the north, as the active depocenter of the Dead Sea Basin migrates northward with time.

Adaptive NN controller design for a class of nonlinear MIMO discrete-time systems.

PubMed

Liu, Yan-Jun; Tang, Li; Tong, Shaocheng; Chen, C L Philip

2015-05-01

An adaptive neural network tracking control is studied for a class of multiple-input multiple-output (MIMO) nonlinear systems. The studied systems are in discrete-time form and the discretized dead-zone inputs are considered. In addition, the studied MIMO systems are composed of N subsystems, and each subsystem contains unknown functions and external disturbance. Due to the complicated framework of the discrete-time systems, the existence of the dead zone and the noncausal problem in discrete-time, it brings about difficulties for controlling such a class of systems. To overcome the noncausal problem, by defining the coordinate transformations, the studied systems are transformed into a special form, which is suitable for the backstepping design. The radial basis functions NNs are utilized to approximate the unknown functions of the systems. The adaptation laws and the controllers are designed based on the transformed systems. By using the Lyapunov method, it is proved that the closed-loop system is stable in the sense that the semiglobally uniformly ultimately bounded of all the signals and the tracking errors converge to a bounded compact set. The simulation examples and the comparisons with previous approaches are provided to illustrate the effectiveness of the proposed control algorithm.

Dead sea asphalts: historical aspects

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

Nissenbaum, A.

1978-05-01

Asphalts are present in the Dead Sea basin in three forms: (1) huge blocks, up to 100 tons in weight, composed of extremely pure (>99.99%) solid asphalt occasionally found floating on the lake, (2) veins, seepages, and cavity and fissure fillings in Lower Cretaceous to Holocene rocks, and (3) ozocerite veins on the eastern shore of the lake. Dead Sea asphalts probably have been documented over a longer period of time than any other hydrocarbon deposit--from antiquity to the 19th century. Major uses of asphalt from the Dead Sea have been as an ingredient in the embalming process, for medicinalmore » purposes, for fumigation, and for agriculture. The first known war for control of a hydrocarbon deposit was in the Dead Sea area in 312 B.C. between the Seleucid Syrians and the Nabatean Arabs who lived around the lake. Surface manifestations of asphalt are linked closely to tectonic activity. In the lake itself, the asphalt is associated with diapirs During certain historic periods, tectonic and diapiric activity caused frequent liberation to the Dead Sea surface of semiliquid asphalt associated with large amounts of hydrogen sulfide gas. When the tectonic activity was attenuated, as in the 19th and 20th centuries, the rate of asphalt seepage to the bottom sediments of the Dead Sea was much slower and the asphalt solidified on the lake bottom. The release of asphalt to the surface became much more sporadic, and may have resulted in part from earthquakes. Thus, future asphalt prospecting in the Dead Sea area should be conducted along the boundaries of diapirs or their associated faults.« less

Relationship between 'live' and dead benthic foraminiferal assemblages in the abyssal NE Atlantic

NASA Astrophysics Data System (ADS)

Stefanoudis, Paris V.; Bett, Brian J.; Gooday, Andrew J.

2017-03-01

Dead foraminiferal assemblages within the sediment mixed layer provide an integrated, time-averaged view of the foraminiferal fauna, while the relationship between dead and live assemblages reflects the population dynamics of different species together with taphonomic processes operating over the last few hundred years. Here, we analysed four samples for 'live' (Rose-Bengal-stained) and dead benthic foraminifera (0-1 cm sediment layer, >150 μm) from four sites in the area of the Porcupine Abyssal Plain Sustained Observatory (PAP-SO; NE Atlantic, 4850 m water depth). Two sites were located on abyssal hills and two on the adjacent abyssal plain. Our results indicate that the transition from live to dead benthic foraminiferal assemblages involved a dramatic loss of delicate agglutinated and organic-walled tests (e.g. Lagenammina, Nodellum, Reophax) with poor preservation potential, and to a lesser extent that of some relatively fragile calcareous tests (mostly miliolids), possibly a result of dissolution. Other processes, such as the transport of tests by bottom currents and predation, are unlikely to have substantially altered the composition of dead faunas. Positive live to dead ratios suggest that some species (notably Epistominella exigua and Bolivina spathulata) may have responded to recent phytodetritus input. Although the composition of live assemblages seemed to be influenced by seafloor topography (abyssal hills vs. plain), no such relation was found for dead assemblages. We suggest that PAP-SO fossil assemblages are likely to be comparable across topographically contrasting sites, and dominated by calcareous and some robust agglutinated forms with calcitic cement (e.g. Eggerella).

Stratigraphy, climate and downhole logging data - an example from the ICDP Dead Sea deep drilling project

NASA Astrophysics Data System (ADS)

Coianiz, Lisa; Ben-Avraham, Zvi; Lazar, Michael

2017-04-01

During the late Quaternary a series of lakes occupied the Dead Sea tectonic basin. The sediments that accumulated within these lakes preserved the environmental history (tectonic and climatic) of the basin and its vicinity. Most of the information on these lakes was deduced from exposures along the marginal terraces of the modern Dead Sea, e.g. the exposures of the last glacial Lake Lisan and Holocene Dead Sea. The International Continental Drilling Program (ICDP) project conducted in the Dead Sea during 2010-2011 recovered several cores that were drilled in the deep depocenter of the lake (water depth of 300 m) and at the margin (depth of 3 m offshore Ein Gedi spa). New high resolution logging data combined with a detailed lithological description and published age models for the deep 5017-1-A borehole were used to establish a sequence stratigraphic framework for the Lakes Amora, Samra, Lisan and Zeelim strata. This study presents a stratigraphic timescale for reconstructing the last ca 225 ka. It provides a context within which the timing of key sequence surfaces identified in the distal part of the basin can be mapped on a regional and stratigraphic time frame. In addition, it permitted the examination of depositional system tracts and related driving mechanisms controlling their formation. The sequence stratigraphic model developed for the Northern Dead Sea Basin is based on the identification of sequence bounding surfaces including: sequence boundary (SB), transgressive surface (TS) and maximum flooding surface (MFS). They enabled the division of depositional sequences into a Lowstand systems tracts (LST), Transgressive systems tracts (TST) and Highstand systems tracts (HST), which can be interpreted in terms of relative lake level changes. The analysis presented here show that system tract stacking patterns defined for the distal 5017-1-A borehole can be correlated to the proximal part of the basin, and widely support the claim that changes in relative lake levels were synchronous across the northern Dead Sea, although differences do exist. These discrepancies can possibly be explained in part by the tectonic nature of the basin. Within the 5017-1-A section, the interpreted changes in depositional environments derived primarily from the gamma ray log patterns show a good correlation in time with sequence-chronostratigraphic framework, extracted lake level curves and paleohydrological records of other areas worldwide. Sequence stratigraphic analysis presented here allows for a detailed, high resolution examination of the sedimentary sequences in the Northern Dead Sea Basin together with an independent proxy that is an indirect indicator of changes in relative lake level.

Identification of the Key Weather Factors Affecting Overwintering Success of Apolygus lucorum Eggs in Dead Host Tree Branches

PubMed Central

Pan, Hongsheng; Liu, Bing; Lu, Yanhui; Desneux, Nicolas

2014-01-01

Understanding the effects of weather on insect population dynamics is crucial to simulate and forecast pest outbreaks, which is becoming increasingly important with the effects of climate change. The mirid bug Apolygus lucorum is an important pest on cotton, fruit trees and other crops in China, and primarily lays its eggs on dead parts of tree branches in the fall for subsequent overwintering. As such, the eggs that hatch the following spring are most strongly affected by ambient weather factors, rather than by host plant biology. In this study, we investigated the effects of three major weather factors: temperature, relative humidity and rainfall, on the hatching rate of A. lucorum eggs overwintering on dead branches of Chinese date tree (Ziziphus jujuba). Under laboratory conditions, rainfall (simulated via soaking) was necessary for the hatching of overwintering A. lucorum eggs. In the absence of rainfall (unsoaked branches), very few nymphs successfully emerged under any of the tested combinations of temperature and relative humidity. In contrast, following simulated rainfall, the hatching rate of the overwintering eggs increased dramatically. Hatching rate and developmental rate were positively correlated with relative humidity and temperature, respectively. Under field conditions, the abundance of nymphs derived from overwintering eggs was positively correlated with rainfall amount during the spring seasons of 2009–2013, while the same was not true for temperature and relative humidity. Overall, our findings indicate that rainfall is the most important factor affecting the hatching rate of overwintering A. lucorum eggs on dead plant parts and nymph population levels during the spring season. It provides the basic information for precisely forecasting the emergence of A. lucorum and subsequently timely managing its population in spring, which will make it possible to regional control of this insect pest widely occurring in multiple crops in summer. PMID:24705353

Identification of the key weather factors affecting overwintering success of Apolygus lucorum eggs in dead host tree branches.

PubMed

Pan, Hongsheng; Liu, Bing; Lu, Yanhui; Desneux, Nicolas

2014-01-01

Understanding the effects of weather on insect population dynamics is crucial to simulate and forecast pest outbreaks, which is becoming increasingly important with the effects of climate change. The mirid bug Apolygus lucorum is an important pest on cotton, fruit trees and other crops in China, and primarily lays its eggs on dead parts of tree branches in the fall for subsequent overwintering. As such, the eggs that hatch the following spring are most strongly affected by ambient weather factors, rather than by host plant biology. In this study, we investigated the effects of three major weather factors: temperature, relative humidity and rainfall, on the hatching rate of A. lucorum eggs overwintering on dead branches of Chinese date tree (Ziziphus jujuba). Under laboratory conditions, rainfall (simulated via soaking) was necessary for the hatching of overwintering A. lucorum eggs. In the absence of rainfall (unsoaked branches), very few nymphs successfully emerged under any of the tested combinations of temperature and relative humidity. In contrast, following simulated rainfall, the hatching rate of the overwintering eggs increased dramatically. Hatching rate and developmental rate were positively correlated with relative humidity and temperature, respectively. Under field conditions, the abundance of nymphs derived from overwintering eggs was positively correlated with rainfall amount during the spring seasons of 2009-2013, while the same was not true for temperature and relative humidity. Overall, our findings indicate that rainfall is the most important factor affecting the hatching rate of overwintering A. lucorum eggs on dead plant parts and nymph population levels during the spring season. It provides the basic information for precisely forecasting the emergence of A. lucorum and subsequently timely managing its population in spring, which will make it possible to regional control of this insect pest widely occurring in multiple crops in summer.

Half-life determination for {sup 108}Ag and {sup 110}Ag

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

Zahn, Guilherme S.; Genezini, Frederico A.

2014-11-11

In this work, the half-life of the short-lived silver radionuclides {sup 108}Ag and {sup 110}Ag were measured by following the activity of samples after they were irradiated in the IEA-R1 reactor. The results were then fitted using a non-paralizable dead time correction to the regular exponential decay and the individual half-life values obtained were then analyzed using both the Normalized Residuals and the Rajeval techniques, in order to reach the most exact and precise final values. To check the validity of dead-time correction, a second correction method was also employed by means of counting a long-lived {sup 60}Co radioactive sourcemore » together with the samples as a livetime chronometer. The final half-live values obtained using both dead-time correction methods were in good agreement, showing that the correction was properly assessed. The results obtained are partially compatible with the literature values, but with a lower uncertainty, and allow a discussion on the last ENSDF compilations' values.« less

Protection against Flavobacterium psychrophilum infection (cold water disease) in Ayu fish (Plecoglossus altivelis) by oral administration of humus extract.

PubMed

NAKAGAWA, Jun; IWASAKI, Tadashi; KODAMA, Hiroshi

2009-11-01

Humic substances are formed during the decomposition of organic matter in humus, and are found in many natural environments in which organic materials and microorganisms have been present. In the present study, oral administration of humus extract to ayu fish (Plecoglossus altivelis) induced effective protection against experimental Flavobacterium psychrophilum infection (cold water disease). Mortality of fish and development of skin lesions, such as erosion and hemorrhages on the skin, gill cover or mouth, were significantly suppressed in fish treated with 10%, 5% or 1% humus extract adsorbed on dry pellets. Although F. psychrophilum was not re-isolated from gills and erosion lesions of the skin of dead fish, bacterial gyrB DNA could be amplified in these specimens from dead fish and surviving control fish using the polymerase chain reaction. The protective effect of the extract was not the results of direct killing of bacteria or antibiotic activity of the extract since no obvious reduction in the bacterial number was observed at 5 times to 5,000 times dilution of the humus extract having pH 5.45 to 7.40. These results clearly show that treating fish with humus extract is effective in preventing cold water disease.

Effects of backlash and dead band on temperature control of the primary loop of a conceptual nuclear Brayton space powerplant

NASA Technical Reports Server (NTRS)

Petrick, E. J.

1973-01-01

An analytical study was made of the stability of a closed-loop liquid-lithium temperature control of the primary loop of a conceptual nuclear Brayton space powerplant. The operating point was varied from 20 to 120 percent of design. A describing-function technique was used to evaluate the effects of temperature dead band and control coupling backlash. From the system investigation, it was predicted that a limit cycle will not exist with a temperature dead band, but a limit cycle will not exist when backlash is present. The results compare favorably with a digital computer simulation.

Time and distance to clear wood in pruned red alder saplings.

Treesearch

Dean S. DeBell; Constance A. Harrington; Barbara L. Gartner; Ryan. Singleton

2006-01-01

Pruning trials in young alder stands were sampled to evaluate response to pruning. Effects of pruning (1) live branches on different dates, and (2) dead branches with or without damaging the branch collar were assessed on trees pruned in 3- and 6-year-old plantations, respectively. Six years after pruning, stem sections were collected and dissected in the longitudinal-...

Prescribed fire effects on field-derived and simulated forest carbon stocks over time

Treesearch

Nicole M. Vaillant; Alicia L. Reiner; Erin K. Noonan-Wright

2013-01-01

To better understand the impact of prescribed fire on carbon stocks, we quantified aboveground and belowground carbon stocks within five pools (live trees and coarse roots, dead trees and coarse roots, live understory vegetation, down woody debris, and litter and duff) and potential carbon emissions from a simulated wildfire before and up to 8 years after prescribed...

Mercury and drought along the lower Carson River, Nevada: IV. Snowy egret post-fledging dispersal, timing of migration and survival, 2002–2004

USGS Publications Warehouse

Henny, Charles J.; Hill, Elwood F.; Grove, Robert A.; Chelgren, Nathan; Haggerty, Patricia K.

2017-01-01

This telemetry study is an extension of our 1997–2006 research on historical mercury contamination on snowy egrets (Egretta thula) up to ~ 20 days of age. Findings from initial studies at the mercury-contaminated Carson River colony at Lahontan Reservoir (LR) and a similar-sized reference (REF) colony on the Humboldt River included mercury-related physiological, biochemical, histopathological and reproductive effects up to ~20 days of age; with poor water years (2000–04), i.e., reduced prey availability, exacerbating effects. Herein, we compare timing of dispersal and migration at LR vs. REF, but the primary question now addressed is “whether survival of young mercury-exposed snowy egrets from LR would be further compromised beyond ~20 days of age? ” Based upon telemetry signals until 90–110 days of age (including dead bird counts and survival rate estimates), we conclude that mercury did not further compromise survival. Dead bird counts and survival rate estimates included time in the colony when fed by adults, plus the critical period when young dispersed from the colony to forage independently. The extended drought during this 3-year study was most critical in 2002 when production of ~20 d old egrets at LR was only 0.24 young/nest. In 2002, survival rates were low at both colonies and we documented the highest counts of dead egrets for both colonies. We suggest the losses in 2002 beyond 20 days of age were more a function of prey availability influenced by drought than exposure to mercury, especially at LR, because higher mercury concentrations, higher survival rates and fewer dead birds were documented at LR in 2003 when water conditions improved. Furthermore, total mercury (THg) in blood in 2003 was more than double 2002 (geometric mean, 3.39 vs 1.47 µg/g wet weight (ww). This higher THg exposure at LR in 2003 was associated with a redistribution of parent and post-dispersal feeding activities upstream (where there was higher mercury from historic mining) related to slightly improved water levels. When comparing the 3-year telemetry findings based upon ~20 d old young at LR (blood THg, geo. means 1.47, 3.39 and 1.89 µg/g ww), we found no evidence that age at dispersal, Julian date at dispersal, timing of migration, or pre-migration survival (~20 to ~100 days post-hatch) were adversely affected by elevated mercury.

Mercury and drought along the lower Carson River, Nevada: IV. Snowy egret post-fledging dispersal, timing of migration and survival, 2002-2004.

PubMed

Henny, Charles J; Hill, Elwood F; Grove, Robert A; Chelgren, Nathan D; Haggerty, Patricia K

2017-01-01

This telemetry study is an extension of our 1997-2006 research on historical mercury contamination on snowy egrets (Egretta thula) up to ~ 20 days of age. Findings from initial studies at the mercury-contaminated Carson River colony at Lahontan Reservoir (LR) and a similar-sized reference (REF) colony on the Humboldt River included mercury-related physiological, biochemical, histopathological and reproductive effects up to ~20 days of age; with poor water years (2000-04), i.e., reduced prey availability, exacerbating effects. Herein, we compare timing of dispersal and migration at LR vs. REF, but the primary question now addressed is "whether survival of young mercury-exposed snowy egrets from LR would be further compromised beyond ~20 days of age? " Based upon telemetry signals until 90-110 days of age (including dead bird counts and survival rate estimates), we conclude that mercury did not further compromise survival. Dead bird counts and survival rate estimates included time in the colony when fed by adults, plus the critical period when young dispersed from the colony to forage independently. The extended drought during this 3-year study was most critical in 2002 when production of ~20d old egrets at LR was only 0.24 young/nest. In 2002, survival rates were low at both colonies and we documented the highest counts of dead egrets for both colonies. We suggest the losses in 2002 beyond 20 days of age were more a function of prey availability influenced by drought than exposure to mercury, especially at LR, because higher mercury concentrations, higher survival rates and fewer dead birds were documented at LR in 2003 when water conditions improved. Furthermore, total mercury (THg) in blood in 2003 was more than double 2002 (geometric mean, 3.39 vs 1.47µg/g wet weight (ww). This higher THg exposure at LR in 2003 was associated with a redistribution of parent and post-dispersal feeding activities upstream (where there was higher mercury from historic mining) related to slightly improved water levels. When comparing the 3-year telemetry findings based upon ~20d old young at LR (blood THg, geo. means 1.47, 3.39 and 1.89µg/g ww), we found no evidence that age at dispersal, Julian date at dispersal, timing of migration, or pre-migration survival (~20 to ~100 days post-hatch) were adversely affected by elevated mercury. Published by Elsevier Inc.

Analysis of single ion channel data incorporating time-interval omission and sampling

PubMed Central

The, Yu-Kai; Timmer, Jens

2005-01-01

Hidden Markov models are widely used to describe single channel currents from patch-clamp experiments. The inevitable anti-aliasing filter limits the time resolution of the measurements and therefore the standard hidden Markov model is not adequate anymore. The notion of time-interval omission has been introduced where brief events are not detected. The developed, exact solutions to this problem do not take into account that the measured intervals are limited by the sampling time. In this case the dead-time that specifies the minimal detectable interval length is not defined unambiguously. We show that a wrong choice of the dead-time leads to considerably biased estimates and present the appropriate equations to describe sampled data. PMID:16849220

Anthropogenic-enhanced erosion following the Neolithic Revolution in the Southern Levant: Records from the Dead Sea deep drilling core

NASA Astrophysics Data System (ADS)

Lu, Yin; Waldmann, Nicolas; Nadel, Dani; Marco, Shmuel

2017-04-01

In addition to tectonics and climatic changes, humans have exerted a significant impact on surface erosion over timescales ranging from years to centuries. However, such kind of impact over millennial timescales remains unsubstantiated. The Dead Sea drainage basin offers a rare combination of well-documented substantial climate change, intense tectonics and abundant archaeological evidence for past human activity in the Southern Levant. It serves as a natural laboratory for understanding how sedimentation rates in a deep basin are related to climate change, tectonics, and anthropogenic impacts on the landscape. Here we show how basin-wide erosion rates are recorded by thicknesses of rhythmic detritus laminae and clastic sediment accumulation rates in a long core retrieved by the Dead Sea Deep Drilling Project in the Dead Sea depocenter. During the last 11.5 kyr the average detrital accumulation rate is 3-4 times that during the last two glacial cycles (MIS 7c-2), and the average thickness of detritus laminae in the last 11.6 kyr is 4.5 times that between 21.7 and 11.6 ka, implying an increased erosion rate on the surrounding slopes during the Holocene. We estimate that this intensified erosion is incompatible with tectonic and climatic regimes during the corresponding time interval and further propose a close association with the Neolithic Revolution in the Levant (beginning at 11.5 ka). We thus suggest that human impact on the landscape was the primary driver causing the intensified erosion and that the Dead Sea sedimentary record serves as a reliable recorder of this impact since the Neolithic Revolution.

Risk assessment of false-positive quantitative real-time PCR results in food, due to detection of DNA originating from dead cells.

PubMed

Wolffs, Petra; Norling, Börje; Rådström, Peter

2005-03-01

Real-time PCR technology is increasingly used for detection and quantification of pathogens in food samples. A main disadvantage of nucleic acid detection is the inability to distinguish between signals originating from viable cells and DNA released from dead cells. In order to gain knowledge concerning risks of false-positive results due to detection of DNA originating from dead cells, quantitative PCR (qPCR) was used to investigate the degradation kinetics of free DNA in four types of meat samples. Results showed that the fastest degradation rate was observed (1 log unit per 0.5 h) in chicken homogenate, whereas the slowest rate was observed in pork rinse (1 log unit per 120.5 h). Overall results indicated that degradation occurred faster in chicken samples than in pork samples and faster at higher temperatures. Based on these results, it was concluded that, especially in pork samples, there is a risk of false-positive PCR results. This was confirmed in a quantitative study on cell death and signal persistence over a period of 28 days, employing three different methods, i.e. viable counts, direct qPCR, and finally floatation, a recently developed discontinuous density centrifugation method, followed by qPCR. Results showed that direct qPCR resulted in an overestimation of up to 10 times of the amount of cells in the samples compared to viable counts, due to detection of DNA from dead cells. However, after using floatation prior to qPCR, results resembled the viable count data. This indicates that by using of floatation as a sample treatment step prior to qPCR, the risk of false-positive PCR results due to detection of dead cells, can be minimized.

20 CFR 219.33 - Evidence of a deemed valid marriage.

Code of Federal Regulations, 2010 CFR

2010-04-01

... marriage was valid; or if the employee is dead, the widow or widower's signed statement to that effect; (3... household when the employee applied for payments; or, if the employee is dead, when he or she died. See...

20 CFR 219.33 - Evidence of a deemed valid marriage.

Code of Federal Regulations, 2014 CFR

2014-04-01

... marriage was valid; or if the employee is dead, the widow or widower's signed statement to that effect; (3... household when the employee applied for payments; or, if the employee is dead, when he or she died. See...

20 CFR 219.33 - Evidence of a deemed valid marriage.

Code of Federal Regulations, 2012 CFR

2012-04-01

... marriage was valid; or if the employee is dead, the widow or widower's signed statement to that effect; (3... household when the employee applied for payments; or, if the employee is dead, when he or she died. See...

20 CFR 219.33 - Evidence of a deemed valid marriage.

Code of Federal Regulations, 2011 CFR

2011-04-01

... marriage was valid; or if the employee is dead, the widow or widower's signed statement to that effect; (3... household when the employee applied for payments; or, if the employee is dead, when he or she died. See...

20 CFR 219.33 - Evidence of a deemed valid marriage.

Code of Federal Regulations, 2013 CFR

2013-04-01

... marriage was valid; or if the employee is dead, the widow or widower's signed statement to that effect; (3... household when the employee applied for payments; or, if the employee is dead, when he or she died. See...

A high-resolution and intelligent dead pixel detection scheme for an electrowetting display screen

NASA Astrophysics Data System (ADS)

Luo, ZhiJie; Luo, JianKun; Zhao, WenWen; Cao, Yang; Lin, WeiJie; Zhou, GuoFu

2018-02-01

Electrowetting display technology is realized by tuning the surface energy of a hydrophobic surface by applying a voltage based on electrowetting mechanism. With the rapid development of the electrowetting industry, how to analyze efficiently the quality of an electrowetting display screen has a very important significance. There are two kinds of dead pixels on the electrowetting display screen. One is that the oil of pixel cannot completely cover the display area. The other is that indium tin oxide semiconductor wire connecting pixel and foil was burned. In this paper, we propose a high-resolution and intelligent dead pixel detection scheme for an electrowetting display screen. First, we built an aperture ratio-capacitance model based on the electrical characteristics of electrowetting display. A field-programmable gate array is used as the integrated logic hub of the system for a highly reliable and efficient control of the circuit. Dead pixels can be detected and displayed on a PC-based 2D graphical interface in real time. The proposed dead pixel detection scheme reported in this work has promise in automating electrowetting display experiments.

Down dead wood statistics for Maine timberlands, 1995

Treesearch

Linda S. Heath; David C. Chojnacky; David C. Chojnacky

2001-01-01

Down dead wood (DDW) is important for its role in carbon and nutrient cycling, carbon sequestration, wildfire behavior, plant reproduction, and wildlife habitat. DDW was measured for the first time during a forest inventory of Maine by the USDA Forest Service in 1994-1996. Pieces greater than 3 feet long and greater than 3 inches in diameter at point of intersection...

The Roles of Beaconing and Dead Reckoning in Human Virtual Navigation

ERIC Educational Resources Information Center

Bodily, Kent D.; Daniel, Thomas A.; Sturz, Bradley R.

2012-01-01

Beaconing is a process in which the distance between a visual landmark and current position is reduced in order to return to a location. In contrast, dead reckoning is a process in which vestibular, kinesthetic and/or optic flow cues are utilized to update speed of movement, elapsed time of movement, and direction of movement to return to a…

Dia de los Muertos: An Illustrated Essay and Bibliography.

ERIC Educational Resources Information Center

California Univ., Santa Barbara. University Library.

Among Mexico's most original traditions is the holiday dedicated to honoring the dead, Dia de los Muertos, November 2. This tradition combines aspects that define the national spirit. At the same time that it is a solemn festivity to remember the dead, it becomes a fiesta in its own right. Death, more than a thing to be feared, becomes the motif…

Explosives remain preferred methods for platform abandonment

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

Pulsipher, A.; Daniel, W. IV; Kiesler, J.E.

1996-05-06

Economics and safety concerns indicate that methods involving explosives remain the most practical and cost-effective means for abandoning oil and gas structures in the Gulf of Mexico. A decade has passed since 51 dead sea turtles, many endangered Kemp`s Ridleys, washed ashore on the Texas coast shortly after explosives helped remove several offshore platforms. Although no relationship between the explosions and the dead turtles was ever established, in response to widespread public concern, the US Minerals Management Service (MMS) and National Marine Fisheries Service (NMFS) implemented regulations limiting the size and timing of explosive charges. Also, more importantly, they requiredmore » that operators pay for observers to survey waters surrounding platforms scheduled for removal for 48 hr before any detonations. If observers spot sea turtles or marine mammals within the danger zone, the platform abandonment is delayed until the turtles leave or are removed. However, concern about the effects of explosives on marine life remains.« less

Adaptive Fault-Tolerant Control of Uncertain Nonlinear Large-Scale Systems With Unknown Dead Zone.

PubMed

Chen, Mou; Tao, Gang

2016-08-01

In this paper, an adaptive neural fault-tolerant control scheme is proposed and analyzed for a class of uncertain nonlinear large-scale systems with unknown dead zone and external disturbances. To tackle the unknown nonlinear interaction functions in the large-scale system, the radial basis function neural network (RBFNN) is employed to approximate them. To further handle the unknown approximation errors and the effects of the unknown dead zone and external disturbances, integrated as the compounded disturbances, the corresponding disturbance observers are developed for their estimations. Based on the outputs of the RBFNN and the disturbance observer, the adaptive neural fault-tolerant control scheme is designed for uncertain nonlinear large-scale systems by using a decentralized backstepping technique. The closed-loop stability of the adaptive control system is rigorously proved via Lyapunov analysis and the satisfactory tracking performance is achieved under the integrated effects of unknown dead zone, actuator fault, and unknown external disturbances. Simulation results of a mass-spring-damper system are given to illustrate the effectiveness of the proposed adaptive neural fault-tolerant control scheme for uncertain nonlinear large-scale systems.

Comparison of nickel biosorption properties of living and dead Rhizopus arrhizus biosorbent

NASA Astrophysics Data System (ADS)

Silah, Hülya; Gül, Ülküye Dudu

2017-04-01

The passive removal of commonly used heavy metal Ni(II), from aqueous solutions by inexpensive biomaterial, fungi Rhizopus arrhizus biomass, termed biosorption, was studied in this study. The effects of biomass type (living and dead) and pH (2-6) on metal removal by fungus were investigated. The dead biomass (44.2%) exhibited higher uptake ability of Ni(II) than living biomass (40.5%) at 100 mg/L heavy metal after 6 h. Optimal pH for biosorption was 6.

Increased sedimentation following the Neolithic Revolution in the Southern Levant

NASA Astrophysics Data System (ADS)

Lu, Yin; Waldmann, Nicolas; Nadel, Dani; Marco, Shmuel

2017-05-01

The Dead Sea drainage basin offers a rare combination of well-documented substantial climate change, intense tectonics and abundant archaeological evidence for past human activity in the Southern Levant. It serves as a natural laboratory for understanding how sedimentation rates in a deep basin are related to climate change, tectonics, and anthropogenic impacts on the landscape. Here we show how basin-wide erosion rates are recorded by thicknesses of rhythmic detritus laminae and clastic sediment accumulation rates in a long core retrieved by the Dead Sea Deep Drilling Project in the Dead Sea depocenter. During the last 11.5 kyr the average detrital accumulation rate is 3-4 times that during the last two glacial cycles (MIS 7c-2), and the average thickness of detritus laminae in the last 11.6 kyr is 4.5 times that between 21.7 and 11.6 ka, implying an increased erosion rate on the surrounding slopes during the Holocene. We estimate that this intensified erosion is incompatible with tectonic and climatic regimes during the corresponding time interval and further propose a close association with the Neolithic Revolution in the Levant (beginning at 11.5 ka). We thus suggest that human impact on the landscape was the primary driver causing the intensified erosion and that the Dead Sea sedimentary record serves as a reliable recorder of this impact since the Neolithic Revolution.

Intraperitoneal insemination and retrograde sperm transport in dairy cows.

PubMed

López-Gatius, F; Yániz, J

2000-03-01

To examine the efficiency of retrograde sperm transport following intraperitoneal insemination, live and dead spermatozoa were used at different concentrations, and sperm recovery from cervical mucus (0.5 ml) 2, 6, 12 and 24 h following insemination was evaluated. Forty lactating Friesian cows, in their second to fourth lactation period, were used in this experiment. Thirty-six cows received intraperitoneally either live or dead spermatozoa. Each group of six cows received one of three total sperm numbers of 30, 45 and 90 million. Four cows were inseminated with 90 million spermatozoa into the uterus and served as a control group. All cows were inseminated towards the end of oestrus. After intrauterine insemination sperm recovery declined, but motile and/or immotile spermatozoa were recovered from all cows at any time. In cows inseminated intraperitoneally, sperm was recovered from the cervix at 6-24 h when 90 million were inseminated. A greater number of spermatozoa was recovered after dead rather than after live sperm inseminations. Only immotile, intact or broken spermatozoa and tail-less heads were recovered after intraperitioneal insemination using either live or dead spermatozoa. No sperm was recovered for 30 and 45 million inseminations. Our results show that, following intraperitoneal insemination, there is passive sperm transport from the peritoneal cavity to the genital tract close to the time of ovulation, and suggest a higher sperm retention in the genital tract when live as opposed to dead spermatozoa are used.

Smith predictor with sliding mode control for processes with large dead times

NASA Astrophysics Data System (ADS)

Mehta, Utkal; Kaya, İbrahim

2017-11-01

The paper discusses the Smith Predictor scheme with Sliding Mode Controller (SP-SMC) for processes with large dead times. This technique gives improved load-disturbance rejection with optimum input control signal variations. A power rate reaching law is incorporated in the sporadic part of sliding mode control such that the overall performance recovers meaningfully. The proposed scheme obtains parameter values by satisfying a new performance index which is based on biobjective constraint. In simulation study, the efficiency of the method is evaluated for robustness and transient performance over reported techniques.

Foehn-induced effects on dust pollution, frontal clouds and solar radiation in the Dead Sea valley

NASA Astrophysics Data System (ADS)

Kishcha, Pavel; Starobinets, Boris; Alpert, Pinhas; Kaplan, Michael

2017-04-01

The significant drying up of the Dead Sea over the past 40 years has led to an increase in an exposed area contributing to local dust pollution. Measurements show that, sometimes, in the Dead Sea valley, dust pollution can reach extreme concentrations up to several thousands of micrograms per cubic meters. Our analysis of a meteorological situation shows that a foehn phenomenon can be a causal factor for the aforementioned extreme local dust concentration. This foehn phenomenon creates strong warm and dry winds, which are accompanied by air turbulence and temperature inversion. In our study, foehn-induced effects on dust pollution, frontal clouds and solar radiation were analyzed over the Judean Mountains ( 1000 m) and over the Dead Sea valley (-420 m), using high-resolution numerical simulations and in-situ observations at meteorological stations located across the mountain ridge. An extreme dust episode occurring on March 22, 2013, was analyzed, which was characterized by measured surface dust concentrations of up to 7000 µg m-3 in the Dead Sea valley. We simulated this foehn phenomenon with the 3-km resolution COSMO-ART model. Our analysis has shown that the foehn phenomenon could be observed even over the relatively low Judean Mountains. This analysis was based on various meteorological, pyranometer, radar, and aerosol measurements together with high-resolution model data. In the Dead Sea valley, the maximum aerosol optical depth (AOD) did not coincide with the maximum surface dust concentration. This lack of coincidence indicates difficulties in using satellite-based AOD for initializing dust concentration within numerical forecast systems over this region with complex terrain. In the western Dead Sea valley, strong foehn winds of over 20 m/s were accompanied by maximal air turbulence leading to maximal local dust emissions. Thus, the model showed that, by creating significant turbulence, the foehn phenomenon intensified the saltation (bombardment) mechanism of local dust generation in the western Dead Sea valley. In addition, the foehn-induced pronounced temperature inversion trapped dust particles beneath this inversion. These two factors caused the measured extreme surface dust concentration in the Dead Sea valley on the specified day. Radar data on March 22 showed a passage of multi-layer frontal cloudiness through the area of the Dead Sea valley leading to a sharp drop in noon solar radiation. The strong descending airflow over the downwind side of the Judean Mountains significantly influenced the frontal cloudiness leading to the formation of a cloud-free band over the Dead Sea valley.

5nsec Dead time multichannel scaling system for Mössbauer spectrometer

NASA Astrophysics Data System (ADS)

Verrastro, C.; Trombetta, G.; Pita, A.; Saragovi, C.; Duhalde, S.

1991-11-01

A PC programmable and fast multichannel scaling module has been designed to use a commercial Mössbauer spectrometer. This module is based on a 10 single chip 8 bits microcomputer (MC6805) and on a 35 fast ALU, which allows a high performance and low cost system. The module can operate in a stand-alone mode. Data analysis are performed in real time display, on XT/AT IBM PC or compatibles. The channels are ranged between 256 and 4096, the maximum number of counts is 232-1 per channel, the dwell time is 3 μsec and the dead time between channels is 5 nsec. A friendly software display the real time spectrum and offers menues with different options at each state.

Submillisecond X-ray photon correlation spectroscopy from a pixel array detector with fast dual gating and no readout dead-time

DOE PAGES

Zhang, Qingteng; Dufresne, Eric M.; Grybos, Pawel; ...

2016-04-19

Small-angle scattering X-ray photon correlation spectroscopy (XPCS) studies were performed using a novel photon-counting pixel array detector with dual counters for each pixel. Each counter can be read out independently from the other to ensure there is no readout dead-time between the neighboring frames. A maximum frame rate of 11.8 kHz was achieved. Results on test samples show good agreement with simple diffusion. Lastly, the potential of extending the time resolution of XPCS beyond the limit set by the detector frame rate using dual counters is also discussed.

Submillisecond X-ray photon correlation spectroscopy from a pixel array detector with fast dual gating and no readout dead-time

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

Zhang, Qingteng; Dufresne, Eric M.; Grybos, Pawel

Small-angle scattering X-ray photon correlation spectroscopy (XPCS) studies were performed using a novel photon-counting pixel array detector with dual counters for each pixel. Each counter can be read out independently from the other to ensure there is no readout dead-time between the neighboring frames. A maximum frame rate of 11.8 kHz was achieved. Results on test samples show good agreement with simple diffusion. Lastly, the potential of extending the time resolution of XPCS beyond the limit set by the detector frame rate using dual counters is also discussed.

Submillisecond X-ray photon correlation spectroscopy from a pixel array detector with fast dual gating and no readout dead-time.

PubMed

Zhang, Qingteng; Dufresne, Eric M; Grybos, Pawel; Kmon, Piotr; Maj, Piotr; Narayanan, Suresh; Deptuch, Grzegorz W; Szczygiel, Robert; Sandy, Alec

2016-05-01

Small-angle scattering X-ray photon correlation spectroscopy (XPCS) studies were performed using a novel photon-counting pixel array detector with dual counters for each pixel. Each counter can be read out independently from the other to ensure there is no readout dead-time between the neighboring frames. A maximum frame rate of 11.8 kHz was achieved. Results on test samples show good agreement with simple diffusion. The potential of extending the time resolution of XPCS beyond the limit set by the detector frame rate using dual counters is also discussed.

Effect of long-term understory prescribed burning on standing and down dead woody material in dry upland oak forests

USGS Publications Warehouse

Polo, John A.; Hallgren, S.W.; Leslie,, David M.

2013-01-01

Dead woody material, long ignored or viewed as a nuisance for forest management, has gained appreciation for its many roles in the forest including wildlife habitat, nutrient storage and cycling, energy for trophic webs, protection of soil, fuel for fire and carbon storage. The growing interest in managing dead woody material has created strong demand for greater understanding of factors controlling amounts and turnover. Prescribed burning, an important management tool, may have strong effects of dead woody material given fire’s capacity to create and consume dead woody material. We determined effects of long-term understory prescribed burning on standing and down woody material in upland oak forests in south-central North America. We hypothesized that as frequency of fire increased in these stands the amount of deadwood would decrease and the fine woody material would decrease more rapidly than coarse woody material. The study was conducted in forests dominated by post oak (Quercus stellata) and blackjack oak (Quercus marilandica) in wildlife management areas where understory prescribed burning had been practiced for over 20 years and the range of burn frequencies was 0 (unburned) fires per decade (FPD) to 4.6 FPD. The amount of deadwood was low compared with more productive forests in southeastern North America. The biomass (24.7 Mg ha-1) and carbon stocks (11.7 Mg ha-1) were distributed among standing dead (22%), coarse woody debris (CWD, dia. > 7.5 cm., 12%), fine woody debris (FWD, dia. < 7.5 cm., 23%), and forest floor (43%). There was no evidence that understory prescribed burning influenced the amount and size distribution of standing and down dead woody material. There were two explanations for the lack of a detectable effect. First, a high incidence of severe weather including ice storms and strong winds that produce large amounts of deadwood intermittently in an irregular pattern across the landscape may preclude detecting a strong effect of understory prescribed burning. Second, fire suppression during the first one-half of the 20th Century may have led to encroachment of woody plants into forest gaps and savannas creating a patchwork of young and old stands that produced deadwood of different sizes and at different rates.

Landsat time series and lidar as predictors of live and dead basal area across five bark beetle-affected forests

Treesearch

Benjamin C. Bright; Andrew T. Hudak; Robert E. Kennedy; Arjan J. H. Meddens

2014-01-01

Bark beetle-caused tree mortality affects important forest ecosystem processes. Remote sensing methodologies that quantify live and dead basal area (BA) in bark beetle-affected forests can provide valuable information to forest managers and researchers. We compared the utility of light detection and ranging (lidar) and the Landsat-based detection of trends in...

A path reconstruction method integrating dead-reckoning and position fixes applied to humpback whales.

PubMed

Wensveen, Paul J; Thomas, Len; Miller, Patrick J O

2015-01-01

Detailed information about animal location and movement is often crucial in studies of natural behaviour and how animals respond to anthropogenic activities. Dead-reckoning can be used to infer such detailed information, but without additional positional data this method results in uncertainty that grows with time. Combining dead-reckoning with new Fastloc-GPS technology should provide good opportunities for reconstructing georeferenced fine-scale tracks, and should be particularly useful for marine animals that spend most of their time under water. We developed a computationally efficient, Bayesian state-space modelling technique to estimate humpback whale locations through time, integrating dead-reckoning using on-animal sensors with measurements of whale locations using on-animal Fastloc-GPS and visual observations. Positional observation models were based upon error measurements made during calibrations. High-resolution 3-dimensional movement tracks were produced for 13 whales using a simple process model in which errors caused by water current movements, non-location sensor errors, and other dead-reckoning errors were accumulated into a combined error term. Positional uncertainty quantified by the track reconstruction model was much greater for tracks with visual positions and few or no GPS positions, indicating a strong benefit to using Fastloc-GPS for track reconstruction. Compared to tracks derived only from position fixes, the inclusion of dead-reckoning data greatly improved the level of detail in the reconstructed tracks of humpback whales. Using cross-validation, a clear improvement in the predictability of out-of-set Fastloc-GPS data was observed compared to more conventional track reconstruction methods. Fastloc-GPS observation errors during calibrations were found to vary by number of GPS satellites received and by orthogonal dimension analysed; visual observation errors varied most by distance to the whale. By systematically accounting for the observation errors in the position fixes, our model provides a quantitative estimate of location uncertainty that can be appropriately incorporated into analyses of animal movement. This generic method has potential application for a wide range of marine animal species and data recording systems.

Can dead zones create structures like a transition disk?

NASA Astrophysics Data System (ADS)

Pinilla, Paola; Flock, Mario; Ovelar, Maria de Juan; Birnstiel, Til

2016-12-01

Context. Regions of low ionisation where the activity of the magneto-rotational instability is suppressed, the so-called dead zones, have been suggested to explain gaps and asymmetries of transition disks. Dead zones are therefore a potential cause for the observational signatures of transition disks without requiring the presence of embedded planets. Aims: We investigate the gas and dust evolution simultaneously assuming simplified prescriptions for a dead zone and a magnetohydrodynamic (MHD) wind acting on the disk. We explore whether the resulting gas and dust distribution can create signatures similar to those observed in transition disks. Methods: We imposed a dead zone and/or an MHD wind in the radial evolution of gas and dust in protoplanetary disks. For the dust evolution, we included the transport, growth, and fragmentation of dust particles. To compare with observations, we produced synthetic images in scattered optical light and in thermal emission at mm wavelengths. Results: In all models with a dead zone, a bump in the gas surface density is produced that is able to efficiently trap large particles (≳ 1 mm) at the outer edge of the dead zone. The gas bump reaches an amplitude of a factor of 5, which can be enhanced by the presence of an MHD wind that removes mass from the inner disk. While our 1D simulations suggest that such a structure can be present only for 1 Myr, the structure may be maintained for a longer time when more realistic 2D/3D simulations are performed. In the synthetic images, gap-like low-emission regions are seen at scattered light and in thermal emission at mm wavelengths, as previously predicted in the case of planet-disk interaction. Conclusions: Main signatures of transition disks can be reproduced by assuming a dead zone in the disk, such as gap-like structure in scattered light and millimetre continuum emission, and a lower gas surface density within the dead zone. Previous studies showed that the Rossby wave instability can also develop at the edge of such dead zones, forming vortices and also creating asymmetries.

Bactericidal effect of photocatalytically-active nanostructured TiO2 surfaces on biofilms of the early oral colonizer, Streptococcus oralis.

PubMed

Westas, Emma; Hayashi, Mariko; Cecchinato, Francesca; Wennerberg, Ann; Andersson, Martin; Jimbo, Ryo; Davies, Julia R

2017-08-01

This study evaluated the photocatalytic bactericidal effect of nanostructured anatase-rich titanium dioxide (TiO 2 ) on microbial biofilms. Commercially pure titanium discs were spin-coated with photocatalytic TiO 2 nanoparticles (P25). Uncoated discs were used as control (CTRL). Half of the CTRL and half of the P25-coated surfaces were coated with purified saliva (SAL) to give four different groups (CTRL, CTRL + SAL, P25 and P25 + SAL). Streptococcus oralis were allowed to form biofilms on the discs for 18 h and non-adherent cells were rinsed off. Bacterial viability was assessed at time 0 with Live/Dead BacLight staining and epifluorescence microscopy. The remaining discs were divided into a non-UV group and UVA-irradiated (+UV) group (irradiation time, 6 or 24 h). Thereafter, viability was assessed as above. Viability at time 0 was high and no dead cells were seen on any of the surfaces, even after 24 h, in the absence of UVA. However, after 24 h of exposure, the proportion of viable cells was reduced by 40% on the P25 discs compared to 0 and 6 h, and this effect was enhanced with a salivary pellicle. Members of mixed species biofilms differ in their susceptibility to the bactericidal effect of the surfaces tested and further investigations are needed to optimize the conditions. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 2321-2328, 2017. © 2017 Wiley Periodicals, Inc.

Measuring Sulfur Isotope Ratios from Solid Samples with the Sample Analysis at Mars Instrument and the Effects of Dead Time Corrections

NASA Technical Reports Server (NTRS)

Franz, H. B.; Mahaffy, P. R.; Kasprzak, W.; Lyness, E.; Raaen, E.

2011-01-01

The Sample Analysis at Mars (SAM) instrument suite comprises the largest science payload on the Mars Science Laboratory (MSL) "Curiosity" rover. SAM will perform chemical and isotopic analysis of volatile compounds from atmospheric and solid samples to address questions pertaining to habitability and geochemical processes on Mars. Sulfur is a key element of interest in this regard, as sulfur compounds have been detected on the Martian surface by both in situ and remote sensing techniques. Their chemical and isotopic composition can belp constrain environmental conditions and mechanisms at the time of formation. A previous study examined the capability of the SAM quadrupole mass spectrometer (QMS) to determine sulfur isotope ratios of SO2 gas from a statistical perspective. Here we discuss the development of a method for determining sulfur isotope ratios with the QMS by sampling SO2 generated from heating of solid sulfate samples in SAM's pyrolysis oven. This analysis, which was performed with the SAM breadboard system, also required development of a novel treatment of the QMS dead time to accommodate the characteristics of an aging detector.

Evaluation of dead-time corrections for post-radionuclide-therapy (177)Lu quantitative imaging with low-energy high-resolution collimators.

PubMed

Celler, Anna; Piwowarska-Bilska, Hanna; Shcherbinin, Sergey; Uribe, Carlos; Mikolajczak, Renata; Birkenfeld, Bozena

2014-01-01

Dead-time (DT) effects rarely cause problems in diagnostic single-photon emission computed tomography (SPECT) studies; however, in post-radionuclide-therapy imaging, DT can be substantial. Therefore, corrections may be necessary if quantitative images are used in image-based dosimetry or for evaluation of therapy outcomes. This task is particularly challenging if low-energy collimators are used. Our goal was to design a simple method to determine the dead-time correction factor (DTCF) without the need for phantom experiments and complex calculations. Planar and SPECT/CT scans of a water phantom containing a 70 ml bottle filled with lutetium-177 (Lu) were acquired over 60 days. Two small Lu markers were used in all scans. The DTCF based on the ratio of observed to true count rates measured over the entire spectrum and using photopeak primary photons only was estimated for phantom (DT present) and marker (no DT) scans. In addition, variations in counts in SPECT projections (potentially caused by varying bremsstrahlung and scatter) were investigated. For count rates that were about two-fold higher than typically seen in post-therapy Lu scans, the maximum DTCF reached a level of about 17%. The DTCF values determined directly from the phantom experiments using the total energy spectrum and photopeak counts only were equal to 13 and 16%, respectively. They were closely matched by those from the proposed marker-based method, which uses only two energy windows and measures photopeak primary photons (15-17%). A simple, marker-based method allowing for determination of the DTCF in high-activity Lu imaging studies has been proposed and validated using phantom experiments.

Are vent crab behavioral preferences adaptations for habitat choice?

PubMed

Dahms, Hans-Uwe; Tseng, Li-Chun; Hwang, Jiang-Shiou

2017-01-01

Hydrothermal vent organisms are adapted to their extreme and patchily distributed habitats. They are expected to have evolved mechanisms that keep them in their specific habitation. Since little is known about the recruitment or habitat selection of HV organisms such as brachyurans, we examined the properties of several hydrothermal vent-associated cues on the behavior of the hydrothermal vent (HV) crab Xenograpsus testudinatus in the laboratory that were contrasted by the offering of non-vent cues. This crab species is endemic and dominates the vent fauna of Turtle Island off the NE coast of Taiwan. HV crabs were separately and in combination offered the following vent-specific cues: (1) sulfuric sediment, (3) air-bubbling, (4) elevated temperature, (5) dead settled zooplankton, (7) other crabs, and (8) shade. The non-vent-specific cues were: (2) quarz sediment, (6) dead fish, (8) light. These cues were provided on either side of a two-choice chamber. The movement of individual crabs was monitored: as initial and final choices, and as the proportion of time the crabs spent in each compartment (resident time). Cues were offered alone and no such cue as a control in the same set-up. Sulfuric sediments and dead fish were significantly more attractive to females, and other crabs irrespective of gender were significantly more attractive to males. When compared to expected distributions, crabs, irrespective of gender, significantly avoided light and tended to select other crabs, air-bubbling, sulfuric sediment, elevated temperature, dead fish, dead zooplankton, and quarz sediments in the order of decreasing importance. Data do not support the hypothesis that dead settled zooplankton was particularly attractive nor that the other gender was selected. A combination of several vent-associated cues (sulfuric sediment, elevated temperature, air-bubbling) facilitated the strongest attraction to the crabs as reflected by all response variables. The 'first choice' responses were always consistent with the side of the choice compartment in which they spent the longest amount of time (resident time), but not with the 'final choice' of crabs, suggesting that the 'resident time' in addition to their 'first choice' is more reliable than just the 'final choice'. The present results provide the first indication that several vent-associated habitat cues function as attractors for HV crabs. Habitat choice is also reflected by crab larval distribution in the field which tend to stay near the bottom not to be carried away from their specific habitat.

Quantification of dead vegetation fraction in mixed pastures using AisaFENIX imaging spectroscopy data

NASA Astrophysics Data System (ADS)

Pullanagari, R. R.; Kereszturi, G.; Yule, I. J.

2017-06-01

New Zealand farming relies heavily on grazed pasture for feeding livestock; therefore it is important to provide high quality palatable grass in order to maintain profitable and sustainable grassland management. The presence of non-photosynthetic vegetation (NPV) such as dead vegetation in pastures severely limits the quality and productivity of pastures. Quantifying the fraction of dead vegetation in mixed pastures is a great challenge even with remote sensing approaches. In this study, a high spatial resolution with pixel resolution of 1 m and spectral resolution of 3.5-5.6 nm imaging spectroscopy data from AisaFENIX (380-2500 nm) was used to assess the fraction of dead vegetation component in mixed pastures on a hill country farm in New Zealand. We used different methods to retrieve dead vegetation fraction from the spectra; narrow band vegetation indices, full spectrum based partial least squares (PLS) regression and feature selection based PLS regression. Among all approaches, feature selection based PLS model exhibited better performance in terms of prediction accuracy (R2CV = 0.73, RMSECV = 6.05, RPDCV = 2.25). The results were consistent with validation data, and also performed well on the external test data (R2 = 0.62, RMSE = 8.06, RPD = 2.06). In addition, statistical tests were conducted to ascertain the effect of topographical variables such as slope and aspect on the accumulation of the dead vegetation fraction. Steep slopes (>25°) had a significantly (p < 0.05) higher amount of dead vegetation. In contrast, aspect showed non-significant impact on dead vegetation accumulation. The results from the study indicate that AisaFENIX imaging spectroscopy data could be a useful tool for mapping the dead vegetation fraction accurately.

Effect of alpha-tocopherol on bovine in vitro fertilization.

PubMed

Marques, A; Santos, P; Antunes, G; Chaveiro, A; Moreira da Silva, F

2010-02-01

The objectives of this work are to determine if exogenous supplementation with alpha-tocopherol increases the in vitro fertilization (IVF) rate of bovine oocytes and improves viability of selected spermatozoa after 'swim-up'. The percentage of fertilized oocytes was significantly but negatively correlated (r = -0.941, p < 0.01) with the concentration of alpha-tocopherol. The control resulted in 95% of fertilized oocytes, which decreased as follows: 25 microM alpha-tocopherol (alpha25) 86%, 50 microM alpha-tocopherol (alpha50) 74%, 100 microM alpha-tocopherol (alpha100) 66% and 200 microM alpha-tocopherol (alpha200) 56%. Relatively to sperm viability after 'swim-up' with alpha-tocopherol supplementation, this antioxidant proved to have a beneficial effect as its concentration increased up to alpha50, decreasing for the concentrations of alpha100 and alpha200. Control resulted in 83% of live cells and 16% of dead cells; alpha25 resulted in 88% of live cells and 12% of dead cells; alpha50 resulted in 91% of live cells and 9% of dead cells; alpha100 resulted in 67% of live cells and 33% of dead cells; and finally alpha200 resulted in 57% of live cells and 42% of dead cells. In summary, the present study allows to conclude that, in our conditions, supplementation with the antioxidant alpha-tocopherol in IVF of bovine oocytes has a detrimental effect on fertilization rates. Nevertheless, exogenous supplementation with alpha-tocopherol at a concentration of 50 mM in the sperm-TALP media during the 'swim-up' technique has a significant beneficial effect on the selected spermatozoa viability.

New perspectives on interdisciplinary earth science at the Dead Sea: The DESERVE project.

PubMed

Kottmeier, Christoph; Agnon, Amotz; Al-Halbouni, Djamil; Alpert, Pinhas; Corsmeier, Ulrich; Dahm, Torsten; Eshel, Adam; Geyer, Stefan; Haas, Michael; Holohan, Eoghan; Kalthoff, Norbert; Kishcha, Pavel; Krawczyk, Charlotte; Lati, Joseph; Laronne, Jonathan B; Lott, Friederike; Mallast, Ulf; Merz, Ralf; Metzger, Jutta; Mohsen, Ayman; Morin, Efrat; Nied, Manuela; Rödiger, Tino; Salameh, Elias; Sawarieh, Ali; Shannak, Benbella; Siebert, Christian; Weber, Michael

2016-02-15

The Dead Sea region has faced substantial environmental challenges in recent decades, including water resource scarcity, ~1m annual decreases in the water level, sinkhole development, ascending-brine freshwater pollution, and seismic disturbance risks. Natural processes are significantly affected by human interference as well as by climate change and tectonic developments over the long term. To get a deep understanding of processes and their interactions, innovative scientific approaches that integrate disciplinary research and education are required. The research project DESERVE (Helmholtz Virtual Institute Dead Sea Research Venue) addresses these challenges in an interdisciplinary approach that includes geophysics, hydrology, and meteorology. The project is implemented by a consortium of scientific institutions in neighboring countries of the Dead Sea (Israel, Jordan, Palestine Territories) and participating German Helmholtz Centres (KIT, GFZ, UFZ). A new monitoring network of meteorological, hydrological, and seismic/geodynamic stations has been established, and extensive field research and numerical simulations have been undertaken. For the first time, innovative measurement and modeling techniques have been applied to the extreme conditions of the Dead Sea and its surroundings. The preliminary results show the potential of these methods. First time ever performed eddy covariance measurements give insight into the governing factors of Dead Sea evaporation. High-resolution bathymetric investigations reveal a strong correlation between submarine springs and neo-tectonic patterns. Based on detailed studies of stratigraphy and borehole information, the extension of the subsurface drainage basin of the Dead Sea is now reliably estimated. Originality has been achieved in monitoring flash floods in an arid basin at its outlet and simultaneously in tributaries, supplemented by spatio-temporal rainfall data. Low-altitude, high resolution photogrammetry, allied to satellite image analysis and to geophysical surveys (e.g. shear-wave reflections) has enabled a more detailed characterization of sinkhole morphology and temporal development and the possible subsurface controls thereon. All the above listed efforts and scientific results take place with the interdisciplinary education of young scientists. They are invited to attend joint thematic workshops and winter schools as well as to participate in field experiments. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

DNA-carbon nano onion aggregate: triangle, hexagon, six-petal flower to dead-end network

NASA Astrophysics Data System (ADS)

Babar, Dipak Gorakh; Pakhira, Bholanath; Sarkar, Sabyasachi

2017-08-01

The interaction between calf-thymus (CT) dsDNA and water soluble carbon nano onion (wsCNO) in water follows denaturation of dsDNA (double stranded) to ssDNA (single stranded) as monitored by optical spectroscopy. The ssDNA concomitantly wraps the spiky surface of wsCNO to create triangular aggregate as the building block as observed by time-dependent SEM images. These triangles further aggregate leading to six-petal flower arrangement via hexagon and finally reach a dead end network as imaged by SEM and optical fluorescence microscopy. The dead-end network aggregate lost the intrinsic optical property of DNA suggesting complete loss of its activity.

Effect of Antibiotics and Antibiofilm Agents in the Ultrastructure and Development of Biofilms Developed by Nonpigmented Rapidly Growing Mycobacteria.

PubMed

Muñoz-Egea, María-Carmen; García-Pedrazuela, María; Mahillo-Fernandez, Ignacio; Esteban, Jaime

2016-01-01

We analyze the effect of amikacin, ciprofloxacin, and clarithromycin, alone and associated with N-acetylcysteine (NAC) and Tween 80, at different times and concentrations in nonpigmented rapidly growing mycobacteria (NPRGM) biofilms. For this purpose, confocal laser scanning microscopy and image analysis were used to study the development and behavior of intrinsic autofluorescence, covered area, thickness, and cell viability in NPRGM biofilms after adding antibiotics alone and associated with antibiofilm agents. In this study, ciprofloxacin is the most active antibiotic against this type of biofilm and thickness is the most affected parameter. NAC and Tween 80 combined with antibiotics exert a synergistic effect in increasing the percentage of dead bacteria and also reducing the percentage of covered surface and thickness of NPRGM biofilms. Tween 80 seems to be an antibiofilm agent more effective than NAC due to its higher reduction in the percentage of cover surface and thickness. In conclusion, the results obtained in this work show that phenotypic parameters (thickness, percentage of covered surface, autofluorescence, percentage of live/dead bacteria) are affected by combining antibiotics and antibiofilm agents, ciprofloxacin and Tween 80 being the most active agents against NPRGM biofilms.

Comparison of the performance of different instruments in the stray neutron field around the CERN Proton Synchrotron.

PubMed

Aza, Eleni; Caresana, Marco; Cassell, Christopher; Colombo, Valeria; Damjanovic, Sanja; Gilardoni, Simone; Manessi, Giacomo Paolo; Pangallo, Michel; Perrin, Daniel; Silari, Marco

2014-10-01

This paper discusses an intercomparison campaign carried out in several locations around the CERN Proton Synchrotron. The locations were selected in order to perform the measurements in different stray field conditions. Various neutron detectors were employed: ionisation chambers, conventional and extended range rem counters, both commercial and prototype ones, including a novel instrument called LUPIN, specifically conceived to work in pulsed fields. The attention was focused on the potential differences in the instrument readings due to dead-time losses that are expected to affect most commercial units. The results show that the ionisation chambers and LUPIN agree well with the expected H*(10) values, as derived from FLUKA simulations, showing no relevant underestimations even in strongly pulsed fields. On the contrary, the dead-time losses of the other rem counters induced an underestimation in pulsed fields that was more important for instruments characterised by a higher dead time. © The Author 2013. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

MAGNETIZED ACCRETION AND DEAD ZONES IN PROTOSTELLAR DISKS

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

Dzyurkevich, Natalia; Henning, Thomas; Turner, Neal J.

The edges of magnetically dead zones in protostellar disks have been proposed as locations where density bumps may arise, trapping planetesimals and helping form planets. Magneto-rotational turbulence in magnetically active zones provides both accretion of gas on the star and transport of mass to the dead zone. We investigate the location of the magnetically active regions in a protostellar disk around a solar-type star, varying the disk temperature, surface density profile, and dust-to-gas ratio. We also consider stellar masses between 0.4 and 2 M{sub Sun }, with corresponding adjustments in the disk mass and temperature. The dead zone's size andmore » shape are found using the Elsasser number criterion with conductivities including the contributions from ions, electrons, and charged fractal dust aggregates. The charged species' abundances are found using the approach proposed by Okuzumi. The dead zone is in most cases defined by the ambipolar diffusion. In our maps, the dead zone takes a variety of shapes, including a fish tail pointing away from the star and islands located on and off the midplane. The corresponding accretion rates vary with radius, indicating locations where the surface density will increase over time, and others where it will decrease. We show that density bumps do not readily grow near the dead zone's outer edge, independently of the disk parameters and the dust properties. Instead, the accretion rate peaks at the radius where the gas-phase metals freeze out. This could lead to clearing a valley in the surface density, and to a trap for pebbles located just outside the metal freezeout line.« less

The deeper structure of the southern Dead Sea basin derived from neural network analysis of velocity and attenuation tomography

NASA Astrophysics Data System (ADS)

Braeuer, Benjamin; Haberland, Christian; Bauer, Klaus; Weber, Michael

2014-05-01

The Dead Sea basin is a pull-apart basin at the Dead Sea transform fault, the boundary between the African and the Arabian plates. Though the DSB has been studied for a long time, the available knowledge - based mainly on surface geology, drilling and seismic reflection surveys - gives only a partial picture of its shallow structure. Therefore, within the framework of the international DESIRE (DEad Sea Integrated REsearch) project, a dense temporary local seismological network was operated in the southern Dead Sea area. Within 18 month of recording 650 events were detected. In addition to an already published tomography study revealing the distribution of P velocities and the Vp/Vs ratios a 2D P-wave attenuation tomography (parameter Qp) was performed. The neural network technique of Self-organizing maps (SOM) is used for the joint interpretation of these three parameters (Vp, Vp/Vs, Qp). The resulting clusters in the petrophysical parameter space are assigned to the main lithological units below the southern part of the Dead Sea basin: (1) The basin sediments characterized by strong attenuation, high vp/vs ratios and low P velocities. (2) The pre-basin sediments characterized by medium to strong attenuation, low Vp/Vs ratios and medium P velocities. (3) The basement characterized by low to moderate attenuation, medium vp/vs ratios and high P velocities. Thus, the asymmetric southern Dead Sea basin is filled with basin sediments down to depth of 7 to 12 km. Below the basin sediments, the pre-basin sediments are extending to a depth between 13 and 18 km.

TIME management by medicinal larvae.

PubMed

Pritchard, David I; Čeřovský, Václav; Nigam, Yamni; Pickles, Samantha F; Cazander, Gwendolyn; Nibbering, Peter H; Bültemann, Anke; Jung, Wilhelm

2016-08-01

Wound bed preparation (WBP) is an integral part of the care programme for chronic wounds. The acronym TIME is used in the context of WBP and describes four barriers to healing in chronic wounds; namely, dead Tissue, Infection and inflammation, Moisture imbalance and a non-migrating Edge. Larval debridement therapy (LDT) stems from observations that larvae of the blowfly Lucilia sericata clean wounds of debris. Subsequent clinical studies have proven debriding efficacy, which is likely to occur as a result of enzymatically active alimentary products released by the insect. The antimicrobial, anti-inflammatory and wound healing activities of LDT have also been investigated, predominantly in a pre-clinical context. This review summarises the findings of investigations into the molecular mechanisms of LDT and places these in context with the clinical concept of WBP and TIME. It is clear from these findings that biotherapy with L. sericata conforms with TIME, through the enzymatic removal of dead tissue and its associated biofilm, coupled with the secretion of defined antimicrobial peptides. This biotherapeutic impact on the wound serves to reduce inflammation, with an associated capacity for an indirect effect on moisture imbalance. Furthermore, larval serine proteinases have the capacity to alter fibroblast behaviour in a manner conducive to the formation of granulation tissue. © 2015 Medicalhelplines.com Inc and John Wiley & Sons Ltd.

Cell death induced by Morarah and Khaltita in hepatoma cancer cells (Huh-7).

PubMed

Baig, Saeeda; Alamgir, Mohiuddin

2009-10-01

To compare the combined and isolated growth inhibitory effects of Morarah and Khaltita (herbs) on hepatoma cell lines (Huh-7), through induction of apoptosis or necrosis. Comparative controlled in-vitro study. The Molecular Biology Laboratory, The Aga Khan University, Karachi, from June to December 2006. The growth of hepatoma cell lines (Huh-7) was checked by adding Khaltita and Morarah to the cells before culture in a 24 well plate. Six wells were selected and labeled for each of the four variables (controls, Khaltita, Morarah and mixture). After 2 days, cells were studied under an inverted phase contrast microscope and fields were recorded. Approximately four fields per slide of higher intensity were selected randomly to determine the dead cell density, and the procedure was repeated 10 or more times. Frequency and percentages were calculated for dead or alive cells in controls, Morarah, Khaltita and their mixture. Chi-square was used to compare the qualitative variables. P-values < 0.05 were considered significant. Morarah and Khaltita were found to induce statistically significant (p < 0.001) cell death in hepatoma cell lines (Huh-7). At a magnification of 40x, the controls showed 1% dead cells compared to 91% in Morarah, 83% in Khaltita and 73% in combined mixture of Khaltita and Morarah. At magnification of 20x, the controls showed 4% dead cells compared to 44% in Morarah, 47% in Khaltita and 49% in the combined mixture of Khaltita and Morarah. Morarah and Khaltita induced cell death in cultured hepatoma cells (Huh-7).

The Dead Sea, The Lake and Its Setting

NASA Astrophysics Data System (ADS)

Brink, Uri ten

I cannot think of a subject more befitting the description of interdisciplinary research with societal relevance than the study of the Dead Sea, a terminal lake of the Jordan River in Israel and Jordan. The scientific study of the Dead Sea is intimately connected with politics, religion, archeology, economic development, tourism, and environmental change.The Dead Sea is a relatively closed geologic and limnologic system with drastic physical changes often occurring on human timescales and with a long human history to observe these changes. Research in this unique area covers diverse aspects such as active subsidence and deformation along strike-slip faults; vertical stratification and stability of the water column; physical properties of extremely saline and dense (1234 kg/m3) water; spontaneous precipitation of minerals in an oversaturated environment; origin of the unusual chemical composition of the brine; existence of life in extreme environments; use of lake level fluctuations as a paleoclimatic indicator; and effects on the environment of human intervention versus natural climatic variability. Although the Dead Sea covers a small area on a global scale, it is nevertheless one of the largest natural laboratories for these types of research on Earth. These reasons make the Dead Sea a fascinating topic for the curious mind.

Counting-loss correction for X-ray spectroscopy using unit impulse pulse shaping.

PubMed

Hong, Xu; Zhou, Jianbin; Ni, Shijun; Ma, Yingjie; Yao, Jianfeng; Zhou, Wei; Liu, Yi; Wang, Min

2018-03-01

High-precision measurement of X-ray spectra is affected by the statistical fluctuation of the X-ray beam under low-counting-rate conditions. It is also limited by counting loss resulting from the dead-time of the system and pile-up pulse effects, especially in a high-counting-rate environment. In this paper a detection system based on a FAST-SDD detector and a new kind of unit impulse pulse-shaping method is presented, for counting-loss correction in X-ray spectroscopy. The unit impulse pulse-shaping method is evolved by inverse deviation of the pulse from a reset-type preamplifier and a C-R shaper. It is applied to obtain the true incoming rate of the system based on a general fast-slow channel processing model. The pulses in the fast channel are shaped to unit impulse pulse shape which possesses small width and no undershoot. The counting rate in the fast channel is corrected by evaluating the dead-time of the fast channel before it is used to correct the counting loss in the slow channel.

Output statistics of laser anemometers in sparsely seeded flows

NASA Technical Reports Server (NTRS)

Edwards, R. V.; Jensen, A. S.

1982-01-01

It is noted that until very recently, research on this topic concentrated on the particle arrival statistics and the influence of the optical parameters on them. Little attention has been paid to the influence of subsequent processing on the measurement statistics. There is also controversy over whether the effects of the particle statistics can be measured. It is shown here that some of the confusion derives from a lack of understanding of the experimental parameters that are to be controlled or known. A rigorous framework is presented for examining the measurement statistics of such systems. To provide examples, two problems are then addressed. The first has to do with a sample and hold processor, the second with what is called a saturable processor. The sample and hold processor converts the output to a continuous signal by holding the last reading until a new one is obtained. The saturable system is one where the maximum processable rate is arrived at by the dead time of some unit in the system. At high particle rates, the processed rate is determined through the dead time.

One life ends, another begins: Management of a brain-dead pregnant mother-A systematic review-

PubMed Central

2010-01-01

Background An accident or a catastrophic disease may occasionally lead to brain death (BD) during pregnancy. Management of brain-dead pregnant patients needs to follow special strategies to support the mother in a way that she can deliver a viable and healthy child and, whenever possible, also be an organ donor. This review discusses the management of brain-dead mothers and gives an overview of recommendations concerning the organ supporting therapy. Methods To obtain information on brain-dead pregnant women, we performed a systematic review of Medline, EMBASE and the Cochrane Central Register of Controlled Trials (CENTRAL). The collected data included the age of the mother, the cause of brain death, maternal medical complications, gestational age at BD, duration of extended life support, gestational age at delivery, indication of delivery, neonatal outcome, organ donation of the mothers and patient and graft outcome. Results In our search of the literature, we found 30 cases reported between1982 and 2010. A nontraumatic brain injury was the cause of BD in 26 of 30 mothers. The maternal mean age at the time of BD was 26.5 years. The mean gestational age at the time of BD and the mean gestational age at delivery were 22 and 29.5 weeks, respectively. Twelve viable infants were born and survived the neonatal period. Conclusion The management of a brain-dead pregnant woman requires a multidisciplinary team which should follow available standards, guidelines and recommendations both for a nontraumatic therapy of the fetus and for an organ-preserving treatment of the potential donor. PMID:21087498

Which Donor for Uterus Transplants: Brain-Dead Donor or Living Donor? A Systematic Review.

PubMed

Lavoué, Vincent; Vigneau, Cécile; Duros, Solène; Boudjema, Karim; Levêque, Jean; Piver, Pascal; Aubard, Yves; Gauthier, Tristan

2017-02-01

The aim of this systematic review was to evaluate and compare the pros and cons of using living donors or brain-dead donors in uterus transplantation programs, 2 years after the first worldwide live birth after uterus transplantation. The Medline database and the Central Cochrane Library were used to locate uterine transplantation studies carried out in human or nonhuman primates. All types of articles (case reports, original studies, meta-analyses, reviews) in English or French were considered for inclusion. Overall, 92 articles were screened and 44 were retained for review. Proof of concept for human uterine transplantation was demonstrated in 2014 with a living donor. Compared with a brain-dead donor strategy, a living donor strategy offers greater possibilities for planning surgery and also decreases cold ischemia time, potentially translating into a higher success rate. However, this approach poses ethical problems, given that the donor is exposed to surgery risks but does not derive any direct benefit. A brain-dead donor strategy is more acceptable from an ethical viewpoint, but its feasibility is currently unproven, potentially owing to a lack of compatible donors, and is associated with a longer cold ischemia time and a potentially higher rejection rate. The systematic review demonstrates that uterine transplantation is a major surgical innovation for the treatment of absolute uterine factor infertility. Living and brain-dead donor strategies are not mutually exclusive and, in view of the current scarcity of uterine grafts and the anticipated future rise in demand, both will probably be necessary.

Metagenomic insights into important microbes from the Dead Zone

NASA Astrophysics Data System (ADS)

Thrash, C.; Baker, B.; Seitz, K.; Temperton, B.; Gillies, L.; Rabalais, N. N.; Mason, O. U.

2015-12-01

Coastal regions of eutrophication-driven oxygen depletion are widespread and increasing in number. Also known as dead zones, these regions take their name from the deleterious effects of hypoxia (dissolved oxygen less than 2 mg/L) on shrimp, demersal fish, and other animal life. Dead zones result from nutrient enrichment of primary production, concomitant consumption by chemoorganotrophic aerobic microorganisms, and strong stratification that prevents ventilation of bottom water. One of the largest dead zones in the world occurs seasonally in the northern Gulf of Mexico (nGOM), where hypoxia can reach up to 22,000 square kilometers. While this dead zone shares many features with more well-known marine oxygen minimum zones, it is nevertheless understudied with regards to the microbial assemblages involved in biogeochemical cycling. We performed metagenomic and metatranscriptomic sequencing on six samples from the 2013 nGOM dead zone from both hypoxic and oxic bottom waters. Assembly and binning led to the recovery of over fifty partial to nearly complete metagenomes from key microbial taxa previously determined to be numerically abundant from 16S rRNA data, such as Thaumarcheaota, Marine Group II Euryarchaeota, SAR406, SAR324, Synechococcus spp., and Planctomycetes. These results provide information about the roles of these taxa in the nGOM dead zone, and opportunities for comparing this region of low oxygen to others around the globe.

Did the ever dead outnumber the living and when? A birth-and-death approach

NASA Astrophysics Data System (ADS)

Avan, Jean; Grosjean, Nicolas; Huillet, Thierry

2015-02-01

This paper is an attempt to formalize analytically the question raised in 'World Population Explained: Do Dead People Outnumber Living, Or Vice Versa?' Huffington Post, Howard (2012). We start developing simple deterministic Malthusian growth models of the problem (with birth and death rates either constant or time-dependent) before running into both linear birth and death Markov chain models and age-structured models.

A dual mode breath sampler for the collection of the end-tidal and dead space fractions.

PubMed

Salvo, P; Ferrari, C; Persia, R; Ghimenti, S; Lomonaco, T; Bellagambi, F; Di Francesco, F

2015-06-01

This work presents a breath sampler prototype automatically collecting end-tidal (single and multiple breaths) or dead space air fractions (multiple breaths). This result is achieved by real time measurements of the CO2 partial pressure and airflow during the expiratory and inspiratory phases. Suitable algorithms, used to control a solenoid valve, guarantee that a Nalophan(®) bag is filled with the selected breath fraction even if the subject under test hyperventilates. The breath sampler has low pressure drop (<0.5 kPa) and uses inert or disposable components to avoid bacteriological risk for the patients and contamination of the breath samples. A fully customisable software interface allows a real time control of the hardware and software status. The performances of the breath sampler were evaluated by comparing (a) the CO2 partial pressure calculated during the sampling with the CO2 pressure measured off-line within the Nalophan(®) bag; (b) the concentrations of four selected volatile organic compounds in dead space, end-tidal and mixed breath fractions. Results showed negligible deviations between calculated and off-line CO2 pressure values and the distributions of the selected compounds into dead space, end-tidal and mixed breath fractions were in agreement with their chemical-physical properties. Copyright © 2015. Published by Elsevier Ltd.

Age depth model construction of the upper section of ICDP Dead Sea Deep Drilling Project based on the high-resolution 14C dating

NASA Astrophysics Data System (ADS)

Kitagawa, H.; Nakamura, T.; Neugebauer, I.; Schwab, M. J.; Brauer, A.; Goldstein, S. L.; Stein, M.

2014-12-01

To reconstruct environmental, climatic and tectonic histories of the Levant, a deep drilling has been accomplished in the northern basin of the Dead Sea during the fall winter of 2010-2011 by the Dead Sea Deep Drilling Project (DSDDP) in the framework of the ICDP program. The sediment cores from site 5017-1 (water depth of ~300 m) recorded the paleoenvironmental and paleohydrological changes in the Dead Sea and the Levant during the last two glacial-interglacial cycles (Neugebauer et al., QSR in press). To provide precise timing of sedimentological - limnological events in the lake and its watershed, and more critically the relative timing of these events, radiocarbon dating of >70 well-preserved terrestrial plants and some carbonate deposits from the upper 150 m long section of the sediment core were performed. Based on the high-resolution radiocarbon dating, a statistical age-depth model was constructed with assumptions on the deposition condition and the radiocarbon age offset of carbonate samples. We discuss the practicality and the limitation of the age-depth model toward interpreting the high-resolution records of environmental, climatic and tectonic events recorded in the long sediment cores from site 5017-1.

Wavelet-based tracking of bacteria in unreconstructed off-axis holograms.

PubMed

Marin, Zach; Wallace, J Kent; Nadeau, Jay; Khalil, Andre

2018-03-01

We propose an automated wavelet-based method of tracking particles in unreconstructed off-axis holograms to provide rough estimates of the presence of motion and particle trajectories in digital holographic microscopy (DHM) time series. The wavelet transform modulus maxima segmentation method is adapted and tailored to extract Airy-like diffraction disks, which represent bacteria, from DHM time series. In this exploratory analysis, the method shows potential for estimating bacterial tracks in low-particle-density time series, based on a preliminary analysis of both living and dead Serratia marcescens, and for rapidly providing a single-bit answer to whether a sample chamber contains living or dead microbes or is empty. Copyright © 2017 Elsevier Inc. All rights reserved.

Digital instrumentation and management of dead time: first results on a NaI well-type detector setup.

PubMed

Censier, B; Bobin, C; Bouchard, J; Aubineau-Lanièce, I

2010-01-01

The LNE-LNHB is engaged in a development program on digital instrumentation, the first step being the instrumentation of a NaI well-type detector set-up. The prototype acquisition card and its technical specifications are presented together with the first comparison with the classical NIM-based acquisition chain, for counting rates up to 100 kcps. The digital instrumentation is shown to be counting-loss free in this range. This validates the main option adopted in this project, namely the implementation of an extending dead time with live-time measurement already successfully used in the MTR2 NIM module developed at LNE-LNHB. Copyright 2010. Published by Elsevier Ltd.

Mortality, fertility, and the OY ratio in a model hunter-gatherer system.

PubMed

White, Andrew A

2014-06-01

An agent-based model (ABM) is used to explore how the ratio of old to young adults (the OY ratio) in a sample of dead individuals is related to aspects of mortality, fertility, and longevity experienced by the living population from which the sample was drawn. The ABM features representations of rules, behaviors, and constraints that affect person- and household-level decisions about marriage, reproduction, and infant mortality in hunter-gatherer systems. The demographic characteristics of the larger model system emerge through human-level interactions playing out in the context of "global" parameters that can be adjusted to produce a range of mortality and fertility conditions. Model data show a relationship between the OY ratios of living populations (the living OY ratio) and assemblages of dead individuals drawn from those populations (the dead OY ratio) that is consistent with that from empirically known ethnographic hunter-gatherer cases. The dead OY ratio is clearly related to the mean ages, mean adult mortality rates, and mean total fertility rates experienced by living populations in the model. Sample size exerts a strong effect on the accuracy with which the calculated dead OY ratio reflects the actual dead OY ratio of the complete assemblage. These results demonstrate that the dead OY ratio is a potentially useful metric for paleodemographic analysis of changes in mortality and mean age, and suggest that, in general, hunter-gatherer populations with higher mortality, higher fertility, and lower mean ages are characterized by lower dead OY ratios. Copyright © 2014 Wiley Periodicals, Inc.

Effects of feeding lactobacillus GG on lethal irradiation in mice

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

Dong, M.Y.; Chang, T.W.; Gorbach, S.L.

1987-05-01

Mice exposed to 1400 rads of total body irradiation experienced 80%-100% mortality in 2 wk. Bacteremia was demonstrated in all dead animals. Feeding Lactobacillus GG strain reduced Pseudomonas bacteremia and prolonged survival time in animals colonized with this organism. In animals not colonized with Pseudomonas, feeding Lactobacillus GG also produced some reduction in early deaths, and there was less Gram-negative bacteremia in these animals compared with controls.

Adaptive Control via Neural Output Feedback for a Class of Nonlinear Discrete-Time Systems in a Nested Interconnected Form.

PubMed

Li, Dong-Juan; Li, Da-Peng

2017-09-14

In this paper, an adaptive output feedback control is framed for uncertain nonlinear discrete-time systems. The considered systems are a class of multi-input multioutput nonaffine nonlinear systems, and they are in the nested lower triangular form. Furthermore, the unknown dead-zone inputs are nonlinearly embedded into the systems. These properties of the systems will make it very difficult and challenging to construct a stable controller. By introducing a new diffeomorphism coordinate transformation, the controlled system is first transformed into a state-output model. By introducing a group of new variables, an input-output model is finally obtained. Based on the transformed model, the implicit function theorem is used to determine the existence of the ideal controllers and the approximators are employed to approximate the ideal controllers. By using the mean value theorem, the nonaffine functions of systems can become an affine structure but nonaffine terms still exist. The adaptation auxiliary terms are skillfully designed to cancel the effect of the dead-zone input. Based on the Lyapunov difference theorem, the boundedness of all the signals in the closed-loop system can be ensured and the tracking errors are kept in a bounded compact set. The effectiveness of the proposed technique is checked by a simulation study.

Responses to the 2800 years BP climatic oscillation in shallow- and deep-basin sediments from the Dead Sea

NASA Astrophysics Data System (ADS)

Neugebauer, Ina; Brauer, Achim; Schwab, Markus; Dulski, Peter; Frank, Ute; Hadzhiivanova, Elitsa; Kitagawa, Hiroyuki; Litt, Thomas; Schiebel, Vera; Taha, Nimer; Waldmann, Nicolas

2015-04-01

Laminated lake sediments from the Dead Sea basin provide high-resolution records of climatic variability in the eastern Mediterranean region, which is considered being especially sensitive to changing climatic conditions. In the study presented here, we aim to reconstruct palaeoclimatic changes and their relation to the frequency of flood/erosion and dust deposition events as archived in the Dead Sea basin for the time interval from ca 3700 to 1700 years BP. A ca 4 m thick, mostly annually laminated (varved) sediment section from the western margin of the Dead Sea (shallow-water DSEn - Ein Gedi profile) was analysed and correlated to the new ICDP Dead Sea Deep Drilling Project core 5017-1 from the deep basin. To detect even single event layers, we applied a multi-proxy approach of high-resolution microscopic thin section analyses, µXRF element scanning and magnetic susceptibility measurements, supported by grain size and palynological analyses. Based on radiocarbon and varve dating two pronounced dry periods were detected at ~3500-3300 yrs BP and ~2900-2400 yrs BP that are characterized by a sand deposit during the older dry period and enhanced frequency of coarse detrital layers during the younger dry period in the shallow-water DSEn core, both interpreted as increased erosion processes. In the 5017-1 deep-basin core these dry periods are depicted by halite deposits. The timing of the younger dry period broadly coincides with the Homeric Minimum of solar activity at ca 2800 yrs BP. Our results suggest that during this period the Dead Sea region experienced a change in synoptic weather patterns leading to an increased occurrence of flash-flood events, overprinting the overall dry climatic conditions. Following this dry spell, a 250-yrs period of increased dust deposition is observed, coinciding with more regular aragonite precipitation during less arid climatic conditions.

Effects of Bacteria on Artemia franciscana Cultured in Different Gnotobiotic Environments

PubMed Central

Marques, Antonio; Dinh, Thi; Ioakeimidis, Christos; Huys, Geert; Swings, Jean; Verstraete, Willy; Dhont, Jean; Sorgeloos, Patrick; Bossier, Peter

2005-01-01

The use of probiotics is receiving considerable attention as an alternative approach to control microbiota in aquaculture farms, especially in hatching facilities. However, application with consistent results is hampered by insufficient information on their modes of action. To investigate whether dead bacteria (allowing investigation of their nutritional effect) or live bacteria (allowing evaluation of their probiotic effect) have any beneficial effect towards Artemia franciscana and, subsequently, if live bacteria have probiotic effects beyond the effects observed with dead bacteria, a model system was employed using gnotobiotic Artemia as a test organism. Nauplii were cultured in the presence of 10 bacterial strains combined with four different major axenic live feeds (two strains of Saccharomyces cerevisiae and two strains of Dunaliella tertiolecta) differing in their nutritional values. In combination with poor- and medium-quality live feeds, dead bacteria exerted a strong effect on Artemia survival but a rather weak or no effect on individual length and constituted a maximum of only 5.9% of the total ash-free dry weight supplied. These effects were reduced or even disappeared when medium- to good-quality major feed sources were used, possibly due to improvements in the health status of Artemia. Some probiotic bacteria, such as GR 8 (Cytophaga spp.), improved (not always significantly) the performance of nauplii beyond the effect observed with dead bacteria, independently of the feed supplied. The present approach can be an excellent system to study the exact mode of action of bacteria, especially if combined with challenge tests or other types of analysis (e.g., transcriptome and proteonomic analysis). PMID:16085818

Synoptic conditions of fine-particle transport to the last interglacial Red Sea-Dead Sea from Nd-Sr compositions of sediment cores

NASA Astrophysics Data System (ADS)

Palchan, Daniel; Stein, Mordechai; Goldstein, Steven L.; Almogi-Labin, Ahuva; Tirosh, Ofir; Erel, Yigal

2018-01-01

The sediments deposited at the depocenter of the Dead Sea comprise high-resolution archive of hydrological changes in the lake's watershed and record the desert dust transport to the region. This paper reconstructs the dust transport to the region during the termination of glacial Marine Isotope Stage 6 (MIS 6; ∼135-129 ka) and the last interglacial peak period (MIS5e, ∼129-116 ka). We use chemical and Nd and Sr isotope compositions of fine detritus material recovered from sediment core drilled at the deepest floor of the Dead Sea. The data is integrated with data achieved from cores drilled at the floor of the Red Sea, thus, forming a Red Sea-Dead Sea transect extending from the desert belt to the Mediterranean climate zone. The Dead Sea accumulated flood sediments derived from three regional surface cover types: settled desert dust, mountain loess-soils and loess-soils filling valleys in the Dead Sea watershed termed here "Valley Loess". The Valley Loess shows a distinct 87Sr/86Sr ratio of 0.7081 ± 1, inherited from dissolved detrital calcites that originate from dried waterbodies in the Sahara and are transported with the dust to the entire transect. Our hydro-climate and synoptic conditions reconstruction illustrates the following history: During glacial period MIS6, Mediterranean cyclones governed the transport of Saharan dust and rains to the Dead Sea watershed, driving the development of both mountain soils and Valley Loess. Then, at Heinrich event 11, dry western winds blew Saharan dust over the entire Red Sea - Dead Sea transect marking latitudinal expansion of the desert belt. Later, when global sea-level rose, the Dead Sea watershed went through extreme aridity, the lake retreated, depositing salt and accumulating fine detritus of the Valley Loess. During peak interglacial MIS 5e, enhanced flooding activity flushed the mountain soils and fine detritus from all around the Dead Sea and Red Sea, marking a significant "contraction" of the desert belt. At the end of MIS 5e the effect of the regional precipitation diminished and the Dead Sea and Red Sea areas re-entered sever arid conditions with extensive salt deposition at the Dead Sea.

Bio-removal of Nickel ions by Sporosarcina pasteurii and Bacillus megaterium, A Comparative Study

NASA Astrophysics Data System (ADS)

Gheethi, AA; Efaq, AN; Mohamed, RM; Abdel-Monem, MO; Halid Abdullah, Abd; Hashim, M. Amir

2017-08-01

The aim of this work was to study the potential of Sporosarcina pasteurii 586S and Bacillus megaterium 1295S isolated from sewage treatment plants (STPs) in removing of nickel ions from the aqueous solution. The bacterial cells were used as living and dead cell biomass. The efficiency of bio-removal process was investigated as a response for nickel and biomass concentrations, time, pH and temperature. The bio-removal capacity (Qmax) of both strains were compared. The highest bio-removal percentage was recorded by dead cells in comparison to living cells. Dead cell biomass of B. megaterium 1295S exhibited higher efficiency for bio-removing of Ni2+ than S. pasteurii 586S at196.4 and 200.2 mg Ni2+ g-1, respectively. It can be concluded that both bacterial strains have high potential to be applied in the biotechnology for removing of Ni2+ ions, however, dead cells of B. megaterium 1295S is the most potent.

Effect of the Presence of Live or Dead Insects on Subsequent Captures of Six Stored-Product Beetle Species: The Relative Species Matters.

PubMed

Athanassiou, Christos G; Kavallieratos, Nickolas G; Campbell, James F

2017-04-01

In trapping programs prior capture of individuals of the same or different species may influence subsequent attractiveness of the trap. To evaluate this process with stored-product insects, the effect of the presence of dead or alive adults in traps on the behavioral responses of six stored-product insect species, Tribolium confusum Jacquelin du Val, T. castaneum (Herbst) (Coleoptera: Tenebrionidae), Sitophilus oryzae (L.), S. granarius (L.) (Coleoptera: Curculionidae), Oryzaephilus surinamensis (L.) and O. mercator (Fauvel) (Coleoptera: Silvanidae), was studied in choice tests under laboratory conditions. Two series of tests were carried out. In the first series, the choice was between either alive or dead adults of same species and blank (no adults). Overall, dead adults had the strongest influence, increasing the response of S. oryzae, S. granarius, O. surinamensis, and O. mercator and decreasing the response of the two Tribolium species. Presence of alive adults generally did not result in a response different from blank, except for T. castaneum and O. surinamensis that had a reduced response. In the second series of tests, the choice was between alive or dead individuals of the species vs. alive or dead individuals of its relative cogeneric species. For choices between alive individuals, S. oryzae, S. granarius, and O. surinamensis showed a preference for alive individuals of the same species vs. the cogeneric species, and for all the other species there was no preference. For choices between dead individuals, T. castaneum exhibited a preference for individuals of the same species, while S. oryzae, S. granarius, and O. mercator showed a preference for individuals of the cogeneric species, and all other combinations did exhibit a preference. Our results suggest that traps containing alive and dead individuals of the same and other species can seriously affect the response and capture of additional insects. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Factors affecting fall down rates of dead aspen (Populus tremuloides) biomass following severe drought in west-central Canada.

PubMed

Ted Hogg, Edward H; Michaelian, Michael

2015-05-01

Increases in mortality of trembling aspen (Populus tremuloides Michx.) have been recorded across large areas of western North America following recent periods of exceptionally severe drought. The resultant increase in standing, dead tree biomass represents a significant potential source of carbon emissions to the atmosphere, but the timing of emissions is partially driven by dead-wood dynamics which include the fall down and breakage of dead aspen stems. The rate at which dead trees fall to the ground also strongly influences the period over which forest dieback episodes can be detected by aerial surveys or satellite remote sensing observations. Over a 12-year period (2000-2012), we monitored the annual status of 1010 aspen trees that died during and following a severe regional drought within 25 study areas across west-central Canada. Observations of stem fall down and breakage (snapping) were used to estimate woody biomass transfer from standing to downed dead wood as a function of years since tree death. For the region as a whole, we estimated that >80% of standing dead aspen biomass had fallen after 10 years. Overall, the rate of fall down was minimal during the year following stem death, but thereafter fall rates followed a negative exponential equation with k = 0.20 per year. However, there was high between-site variation in the rate of fall down (k = 0.08-0.37 per year). The analysis showed that fall down rates were positively correlated with stand age, site windiness, and the incidence of decay fungi (Phellinus tremulae (Bond.) Bond. and Boris.) and wood-boring insects. These factors are thus likely to influence the rate of carbon emissions from dead trees following periods of climate-related forest die-off episodes. © 2014 Her Majesty the Queen in Right of Canada Global Change Biology © 2014 John Wiley & Sons Ltd Reproduced with the permission of the Minister of Natural Resources Canada.

An ever-changing ecological battlefield: marijuana cultivation and toxicant use in western forests

Treesearch

Craig M. Thompson; Mourad W  Gabriel; Kathryn L. Purcell

2017-01-01

Frozen in the act of scavenging dinner, the vulture’s head lay on the fox’s abdomen, covering the hole it had been attempting to enlarge. When biologists pulled the bird away, they found not only a healthy looking, though dead, fox underneath, but also scores of insects scattered around. Less than a mile away the scene was repeated. This time the dead animal...

Comparison of capnovolumetry-derived dead space parameters with pulmonary function test in normal adults using histamine provocation.

PubMed

Sun, Xiaoli; Zhang, Yan; Yang, Wenlan; Liu, Jinming

2015-04-01

This study in healthy adults was conducted to explore the clinical application of capnovolumetric indices as compared to lung function parameters using histamine provocation. Forty healthy subjects received aerosol histamine or salbutamol in an automatic stimulation system with escalating doses of histamine. Dead space volumes of capnovolumetry and lung function parameters were examined with increased concentrations of histamine at a fixed time interval. The doses of histamine were selected from 0.0562 mg-2.2 mg and 0.1 mg salbutamol was inhaled when a maximal dose of histamine was reached. Baseline values in each group were calculated prior to histamine inhalation. Fowler dead space (VDF), Wolff dead space (VDW), threshold dead space (VDT), Bohr dead space (VDB), forced expiratory volume in 1 s (FEV1 ) and peak expiratory flow (PEF) showed a dose-dependent reduction following histamine provocation, but there were no statistical differences in the measurements at baseline and post S6 provocation. The value of dC3/DV at the maximal dose was significantly increased over its baseline value (P < 0.05). VDF, VDT and VDW were significantly increased after bronchodilator use (P < 0.05 or <0.01). The changes in capnovolumetry did not correspond with the results of lung function test. The dC3/DV and airway dead spaces of capnovolumetry in healthy adults are significantly increased compared to lung function parameters before or after bronchodilator use, suggesting that capnovolumetry is feasible in diagnostic evaluation of airway reactivity, especially for persons who are unable to undertake lung function test. © 2014 John Wiley & Sons Ltd.

Live/Dead Comparisons of Ostracodes in Temperate Lakes Reveal Evidence of Human Impact and Provides a Tool to Measure the Progress of Remediation Efforts

NASA Astrophysics Data System (ADS)

Spergel, J.; Kimball, K. C.; Fitzpatrick, S. A.; Michelson, A. V.; Leonard-Pingel, J.

2015-12-01

Lake ecosystems face a multitude of environmental threats including: eutrophication, overfishing, and heavy metal pollution. Tools to identify lakes impacted by human activity and quantify that impact are needed to combat their environmental degradation. One such promising tool has been the comparison between living communities and associated time-averaged death assemblages of mollusks in marine environments. Here we extend the reach of such live/dead comparisons using ostracodes in temperate lakes. We sampled six lakes in Wisconsin for living communities and associated death assemblages of ostracodes: two lakes impacted by human activity, two relatively "pristine" lakes, and two remediated lakes. We took sixteen grab samples of the upper centimeter of sediment in each lake, capturing simultaneously living benthic ostracodes and discarded valves of dead ostracodes. We found that impacted lakes had lower live/dead fidelity in taxonomic composition and rank-order abundance distributions and greater within-lake variation in death assemblages than "pristine" lakes. Additionally, the living communities in the impacted lakes tended to be lower in species richness and have lower evenness than "pristine" lakes. Remediated lakes displayed similar live/dead fidelity in taxonomic composition and rank-abundance distributions to "pristine" lakes and had lower within-lake variation in death assemblages than impacted lakes. Remediated lakes also contained living communities that tended to be richer and more even than impacted lakes. The lower live/dead fidelity of ostracodes in impacted lakes indicate live/dead ostracode comparisons can provide a tool to identify lake ecosystems impacted by humans. The similar results of remediated and "pristine" lakes indicate remediation efforts in these lakes have been successful in alleviating environmental impact detrimental to ostracode communities. This result indicates live/dead comparisons of ostracodes can be a useful tool to monitor the progress of remediation efforts already underway. Further work will focus on dating the upper centimeter of sediment in these lakes to provide an estimate of how long it takes for death assemblages to accumulate and thus how long it will take to regain high live/dead fidelity in impacted lakes undergoing remediation.

Discordance between living and death assemblages as evidence for anthropogenic ecological change

PubMed Central

Kidwell, Susan M.

2007-01-01

Mismatches between the composition of a time-averaged death assemblage (dead remains sieved from the upper mixed-zone of the sedimentary column) and the local living community are typically attributed to natural postmortem processes. However, statistical analysis of 73 molluscan data sets from estuaries and lagoons reveals significantly poorer average “live-dead agreement” in settings of documented anthropogenic eutrophication (AE) than in areas where AE and other human impacts are negligible. Taxonomic similarity of paired live and dead species lists declines steadily among areas as a function of AE severity, and, for data sets comprising only adults, rank-order agreement in species abundance drops where AE is suspected. The observed live-dead differences in composition are consistent with eutrophication (anomalous abundance of seagrass-dwellers and/or scarcity of organic-loving species in the death assemblage), suggesting compositional inertia of death assemblages to recent environmental change. Molluscan data sets from open shelf settings (n = 34) also show higher average live-dead discordance in areas of AE. These results indicate that (i) live-dead discordance in surficial grab samples provides valuable evidence for strong anthropogenic modification of benthic communities, (ii) actualistic estimates of the ecological fidelity of molluscan death assemblages tend to be erroneously pessimistic when conducted in nonpristine settings, and (iii) based on their high fidelity in pristine study areas, death assemblages are a promising means of reconstructing otherwise elusive preimpact ecological baselines from sedimentary records. PMID:17965231

The therapeutic protection of a living and dead Lactobacillus strain against aluminum-induced brain and liver injuries in C57BL/6 mice

PubMed Central

Zhai, Qixiao; Xiao, Yue; Shi, Ying; Jiang, Jinchi; Liu, Xiaoming; Zhao, Jianxin; Zhang, Hao

2017-01-01

Our previous study found that Lactobacillus plantarum CCFM639 had the ability to alleviate acute aluminum (Al) toxicity when the strain was introduced simultaneously with Al exposure. This research was designed to elucidate the therapeutic effects of living and dead L. plantarum CCFM639 against chronic Al toxicity and to gain insight into the protection modes of this strain. Animals were assigned into control, Al only, Al + living CCFM639, and Al + dead CCFM639 groups. The Al exposure model was established by drinking water for the first 4 weeks. The strain was given after Al exposure by oral gavage at 109 colony-forming units once per day for 12 weeks. The results show that the Al binding ability of dead CCFM639 was similar to that of living CCFM639 in vitro. The ingestion of living or dead CCFM639 has similar effects on levels of Al and trace element in tissues, but living strains led to more significant amelioration of oxidative stress and improvement of memory deficits in Al-exposed mice. In conclusion, in addition to intestinal Al sequestration, CCFM639 treatment offers direct protection against chronic Al toxicity by alleviation of oxidative stress. Therefore, L. plantarum CCFM639 has a potential as dietary supplement ingredient that provides protection against Al-induced injury. PMID:28388664

5000 yr of paleoseismicity along the southern Dead Sea fault

NASA Astrophysics Data System (ADS)

Klinger, Y.; Le Béon, M.; Al-Qaryouti, M.

2015-07-01

The 1000-km-long left-lateral Dead Sea fault is a major tectonic structure of the oriental Mediterranean basin, bounding the Arabian Plate to the west. The fault is located in a region with an exceptionally long and rich historical record, allowing to document historical seismicity catalogues with unprecedented level of details. However, if the earthquake time series is well documented, location and lateral extent of past earthquakes remain often difficult to establish, if only based on historical testimonies. We excavated a palaeoseismic trench in a site located in a kilometre-size extensional jog, south of the Dead Sea, in the Wadi Araba. Based on the stratigraphy exposed in the trench, we present evidence for nine earthquakes that produced surface ruptures during a time period spanning 5000 yr. Abundance of datable material allows us to tie the five most recent events to historical earthquakes with little ambiguities, and to constrain the possible location of these historical earthquakes. The events identified at our site are the 1458 C.E., 1212 C.E., 1068 C.E., one event during the 8th century crisis, and the 363 C.E. earthquake. Four other events are also identified, which correlation with historical events remains more speculative. The magnitude of earthquakes is difficult to assess based on evidence at one site only. The deformation observed in the excavation, however, allows discriminating between two classes of events that produced vertical deformation with one order of amplitude difference, suggesting that we could distinguish earthquakes that started/stopped at our site from earthquakes that potentially ruptured most of the Wadi Araba fault. The time distribution of earthquakes during the past 5000 yr is uneven. The early period shows little activity with return interval of ˜500 yr or longer. It is followed by a ˜1500-yr-long period with more frequent events, about every 200 yr. Then, for the past ˜550 yr, the fault has switched back to a quieter mode with no significant earthquake along the entire southern part of the Dead Sea fault, between the Dead Sea and the Gulf of Aqaba. We computed the Coefficient of Variation for our site and three other sites along the Dead Sea fault, south of Lebanon, to compare time distribution of earthquakes at different locations along the fault. With one exception at a site located next to Lake Tiberias, the three other sites are consistent to show some temporal clustering at the scale of few thousands years.

Effects of complex carbon addition to soil CO2 efflux and isotopic composition to soils near dead and live piñon pine trees

NASA Astrophysics Data System (ADS)

Powers, H.; McDowell, N.; Breecker, D. O.

2010-12-01

We test the hypothesis that soils collected near dead and living pinus edulous (piñon pine) trees should show a difference in their capacities to decompose complex carbon compounds. Since soils near dead trees have a large amount of cellulose and other complex carbon, the soil microbial community should be selected to metabolize cellulose. We collected soils from both live and dead piñon trees, added cellulose to half of the replicates, and placed them in microcosms for incubation. The microcosms were periodically sampled by a trace gas analyzer (TGA100, Campbell Scientific, USA) for CO2 concentration and δ13C and δ18O analysis. We found that CO2 evolution rates from live soils were significantly higher than rates from dead soils (1.1 and 0.6 ug CO2 g-1 soil s-1 respectively); soils with added cellulose displayed higher rates (1.1 and 0.8 and ug CO2 g-1 soil s-1). We did not see any significant differences in δ13C values between treatments, but there was a difference in δ18O between soils treated with cellulose and soils with no cellulose. Soils from both dead and live trees showed an increase in CO2 efflux when cellulose was added; however there was no distinguishable difference in efflux rate between live and dead soils in the cellulose added treatments.

Inferential modeling and predictive feedback control in real-time motion compensation using the treatment couch during radiotherapy

NASA Astrophysics Data System (ADS)

Qiu, Peng; D'Souza, Warren D.; McAvoy, Thomas J.; Liu, K. J. Ray

2007-09-01

Tumor motion induced by respiration presents a challenge to the reliable delivery of conformal radiation treatments. Real-time motion compensation represents the technologically most challenging clinical solution but has the potential to overcome the limitations of existing methods. The performance of a real-time couch-based motion compensation system is mainly dependent on two aspects: the ability to infer the internal anatomical position and the performance of the feedback control system. In this paper, we propose two novel methods for the two aspects respectively, and then combine the proposed methods into one system. To accurately estimate the internal tumor position, we present partial-least squares (PLS) regression to predict the position of the diaphragm using skin-based motion surrogates. Four radio-opaque markers were placed on the abdomen of patients who underwent fluoroscopic imaging of the diaphragm. The coordinates of the markers served as input variables and the position of the diaphragm served as the output variable. PLS resulted in lower prediction errors compared with standard multiple linear regression (MLR). The performance of the feedback control system depends on the system dynamics and dead time (delay between the initiation and execution of the control action). While the dynamics of the system can be inverted in a feedback control system, the dead time cannot be inverted. To overcome the dead time of the system, we propose a predictive feedback control system by incorporating forward prediction using least-mean-square (LMS) and recursive least square (RLS) filtering into the couch-based control system. Motion data were obtained using a skin-based marker. The proposed predictive feedback control system was benchmarked against pure feedback control (no forward prediction) and resulted in a significant performance gain. Finally, we combined the PLS inference model and the predictive feedback control to evaluate the overall performance of the feedback control system. Our results show that, with the tumor motion unknown but inferred by skin-based markers through the PLS model, the predictive feedback control system was able to effectively compensate intra-fraction motion.

Active cancellation - A means to zero dead-time pulse EPR.

PubMed

Franck, John M; Barnes, Ryan P; Keller, Timothy J; Kaufmann, Thomas; Han, Songi

2015-12-01

The necessary resonator employed in pulse electron paramagnetic resonance (EPR) rings after the excitation pulse and creates a finite detector dead-time that ultimately prevents the detection of signal from fast relaxing spin systems, hindering the application of pulse EPR to room temperature measurements of interesting chemical or biological systems. We employ a recently available high bandwidth arbitrary waveform generator (AWG) to produce a cancellation pulse that precisely destructively interferes with the resonant cavity ring-down. We find that we can faithfully detect EPR signal at all times immediately after, as well as during, the excitation pulse. This is a proof of concept study showcasing the capability of AWG pulses to precisely cancel out the resonator ring-down, and allow for the detection of EPR signal during the pulse itself, as well as the dead-time of the resonator. However, the applicability of this approach to conventional EPR experiments is not immediate, as it hinges on either (1) the availability of low-noise microwave sources and amplifiers to produce the necessary power for pulse EPR experiment or (2) the availability of very high conversion factor micro coil resonators that allow for pulse EPR experiments at modest microwave power. Copyright © 2015 Elsevier Inc. All rights reserved.

Options for reducing HIV transmission related to the dead space in needles and syringes.

PubMed

Zule, William A; Pande, Poonam G; Otiashvili, David; Bobashev, Georgiy V; Friedman, Samuel R; Gyarmathy, V Anna; Des Jarlais, Don C

2018-01-15

When shared by people who inject drugs, needles and syringes with different dead space may affect the probability of HIV and hepatitis C virus (HCV) transmission differently. We measured dead space in 56 needle and syringe combinations obtained from needle and syringe programs across 17 countries in Europe and Asia. We also calculated the amounts of blood and HIV that would remain in different combinations following injection and rinsing. Syringe barrel capacities ranged from 0.5 to 20 mL. Needles ranged in length from 8 to 38 mm. The average dead space was 3 μL in low dead space syringes with permanently attached needles, 13 μL in high dead space syringes with low dead space needles, 45 μL in low dead space syringes with high dead space needles, and 99 μL in high dead space syringes with high dead space needles. Among low dead space designs, calculated volumes of blood and HIV viral burden were lowest for low dead space syringes with permanently attached needles and highest for low dead space syringes with high dead space needles. The dead space in different low dead space needle and syringe combinations varied substantially. To reduce HIV transmission related to syringe sharing, needle and syringe programs need to combine this knowledge with the needs of their clients.

Design of fast signal processing readout front-end electronics implemented in CMOS 40 nm technology

NASA Astrophysics Data System (ADS)

Kleczek, Rafal

2016-12-01

The author presents considerations on the design of fast readout front-end electronics implemented in a CMOS 40 nm technology with an emphasis on the system dead time, noise performance and power dissipation. The designed processing channel consists of a charge sensitive amplifier with different feedback types (Krummenacher, resistive and constant current blocks), a threshold setting block, a discriminator and a counter with logic circuitry. The results of schematic and post-layout simulations with randomly generated input pulses in a time domain according to the Poisson distribution are presented and analyzed. Dead time below 20 ns is possible while keeping noise ENC ≈ 90 e- for a detector capacitance CDET = 160 fF.

Brought in Dead: An Avoidable Delay in Maternal Deaths.

PubMed

Kumar, Aruna; Agrawal, Neha

2016-10-01

Maternal brought in dead are the patient who dies in the need of adequate medical care. These deaths are often not analyzed sincerely as they are not institutional deaths. Our aim is to find out actual life threatening cause of delay leading to death. Patients brought dead to casualty were seen by the doctors on duty in Department of Obstetrics and Gynaecology,Gandhi Medical College, Bhopal round the clock. Cause of death was analyzed by verbal autopsy of attendants and referral letter from the institute. In this analytical study a complete evaluation of brought deaths from January 2011 to Decmeber 2014 was done. A total of 64 brought in deaths were reported in this 4 year duration. Most common cause of death was postpartum hemorrhage (54.68 %) followed by hypertension (15.62 %) and the most common cause of delay was delay in getting adequate treatment (56.25 %). The brought in dead are the indicator of the three delays in getting health care. Challenges appear to be enormous to be tackled. Timely management proves to be critical in preventing maternal death. Thus it appears that community education about pregnancy and its complications, EmOC training at FRU and strict adherence to referral protocol may help us to reduce the brought dead burden.

Changes of mercury contamination in red-crowned cranes, Grus japonensis, in East Hokkaido, Japan.

PubMed

Teraoka, Hiroki; Tagami, Yukari; Kudo, Moe; Miura, Yoshiaki; Okamoto, Erika; Matsumoto, Fumio; Koga, Kimiya; Uebayashi, Akiko; Shimura, Ryoji; Inoue, Masako; Momose, Kunikazu; Masatomi, Hiroyuki; Kitazawa, Takio; Hiraga, Takeo; Subramanian, Annamalai

2012-07-01

Red-crowned cranes (Grus japonensis) are native to eastern Hokkaido (island population), in contrast to the mainland, which migrates between the Amur River basin and eastern China-Korea peninsula. During the 1990s we found that Red-crowned cranes in Hokkaido were highly contaminated with mercury: however, the source was unknown. We investigated the time trend of mercury contamination in Red-crowned cranes. Total mercury levels in the livers and kidneys from cranes dead in the 2000s were lower than those dead in the 1990s. Feather is a major pathway of mercury excretion for many bird species and is used as an indicator of blood mercury level during feather growth. As internal organs from the specimens collected before 1988 were not available, we analyzed the flight feather shavings from stuffed Red-crowned cranes dead in 1959-1987 and found that the mercury level of feathers from cranes dead in the 1960s and 1970s was not more than those from the cranes dead in the 2000s. These results suggest that mercury contamination in Red-crowned cranes in Hokkaido decreased temporally during the 1990s-2000s. This indicates the possible occurrence of some mercury pollution in Red-crowned cranes' habitat in this region in the 1990s or before.

Self-accelerated development of salt karst during flash floods along the Dead Sea Coast, Israel

NASA Astrophysics Data System (ADS)

Avni, Yoav; Lensky, Nadav; Dente, Elad; Shviro, Maayan; Arav, Reuma; Gavrieli, Ittai; Yechieli, Yoseph; Abelson, Meir; Lutzky, Hallel; Filin, Sagi; Haviv, Itai; Baer, Gidon

2016-01-01

We document and analyze the rapid development of a real-time karst system within the subsurface salt layers of the Ze'elim Fan, Dead Sea, Israel by a multidisciplinary study that combines interferometric synthetic aperture radar and light detection and ranging measurements, sinkhole mapping, time-lapse camera monitoring, groundwater level measurements and chemical and isotopic analyses of surface runoff and groundwater. The >1 m/yr drop of Dead Sea water level and the subsequent change in the adjacent groundwater system since the 1960s resulted in flushing of the coastal aquifer by fresh groundwater, subsurface salt dissolution, gradual land subsidence and formation of sinkholes. Since 2010 this process accelerated dramatically as flash floods at the Ze'elim Fan were drained by newly formed sinkholes. During and immediately after these flood events the dissolution rates of the subsurface salt layer increased dramatically, the overlying ground surface subsided, a large number of sinkholes developed over short time periods (hours to days), and salt-saturated water resurged downstream. Groundwater flow velocities increased by more than 2 orders of magnitudes compared to previously measured velocities along the Dead Sea. The process is self-accelerating as salt dissolution enhances subsidence and sinkhole formation, which in turn increase the ponding areas of flood water and generate additional draining conduits to the subsurface. The rapid terrain response is predominantly due to the highly soluble salt. It is enhanced by the shallow depth of the salt layer, the low competence of the newly exposed unconsolidated overburden and the moderate topographic gradients of the Ze'elim Fan.

Design and Test of a 65nm CMOS Front-End with Zero Dead Time for Next Generation Pixel Detectors

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

Gaioni, L.; Braga, D.; Christian, D.

This work is concerned with the experimental characterization of a synchronous analog processor with zero dead time developed in a 65 nm CMOS technology, conceived for pixel detectors at the HL-LHC experiment upgrades. It includes a low noise, fast charge sensitive amplifier with detector leakage compensation circuit, and a compact, single ended comparator able to correctly process hits belonging to two consecutive bunch crossing periods. A 2-bit Flash ADC is exploited for digital conversion immediately after the preamplifier. A description of the circuits integrated in the front-end processor and the initial characterization results are provided

GUMAP: A GUPIXWIN-compatible code for extracting regional spectra from nuclear microbeam list mode files

NASA Astrophysics Data System (ADS)

Russell, John L.; Campbell, John L.; Boyd, Nicholas I.; Dias, Johnny F.

2018-02-01

The newly developed GUMAP software creates element maps from OMDAQ list mode files, displays these maps individually or collectively, and facilitates on-screen definitions of specified regions from which a PIXE spectrum can be built. These include a free-hand region defined by moving the cursor. The regional charge is entered automatically into the spectrum file in a new GUPIXWIN-compatible format, enabling a GUPIXWIN analysis of the spectrum. The code defaults to the OMDAQ dead time treatment but also facilitates two other methods for dead time correction in sample regions with count rates different from the average.

Factors Affecting the Occurrence of Spinal Reflexes in Brain Dead Cases.

PubMed

Hosseini, Mahsa Sadat; Ghorbani, Fariba; Ghobadi, Omid; Najafizadeh, Katayoun

2015-08-01

Brain death is defined as the permanent absence of all cortical and brain stem reflexes. A wide range of spontaneous or reflex movements that are considered medullary reflexes are observed in heart beating cases that appear brain dead, which may create uncertainty about the diagnosis of brain death and cause delays in deceased-donor organ donation process. We determined the frequency and type of medullary reflexes and factors affecting their occurrence in brain dead cases. During 1 year, 122 cases who fulfilled the criteria for brain death were admitted to the special intensive care unit for organ procurement of Masih Daneshvari Hospital. Presence of spinal reflexes was evaluated by trained coordinators and was recorded in a form in addition to other information including demographic characteristics, cause of brain death, time from detection of brain death, history of craniotomy, vital signs, serum electrolyte levels, and parameters of arterial blood gas determination. Most cases (63%) included in this study were male, and mean age was 33 ± 15 y. There was > 1 spinal reflex observed in 40 cases (33%). The most frequent reflex was plantar response (17%) following by myoclonus (10%), triple flexion reflex (9%), pronator extension reflex (8%), and undulating toe reflex (7%). Mean systolic blood pressure was significantly higher in cases who exhibited medullary reflexes than other cases (126 ± 19 mm Hg vs 116 ± 17 mm Hg; P = .007). Spinal reflexes occur frequently in brain dead cases, especially when they become hemodynamically stable after treatment in the organ procurement unit. Observing these movements by caregivers and family members has a negative effect on obtaining family consent and organ donation. Increasing awareness about spinal reflexes is necessary to avoid suspicion about the brain death diagnosis and delays in organ donation.

The trait contribution to wood decomposition rates of 15 Neotropical tree species.

PubMed

van Geffen, Koert G; Poorter, Lourens; Sass-Klaassen, Ute; van Logtestijn, Richard S P; Cornelissen, Johannes H C

2010-12-01

The decomposition of dead wood is a critical uncertainty in models of the global carbon cycle. Despite this, relatively few studies have focused on dead wood decomposition, with a strong bias to higher latitudes. Especially the effect of interspecific variation in species traits on differences in wood decomposition rates remains unknown. In order to fill these gaps, we applied a novel method to study long-term wood decomposition of 15 tree species in a Bolivian semi-evergreen tropical moist forest. We hypothesized that interspecific differences in species traits are important drivers of variation in wood decomposition rates. Wood decomposition rates (fractional mass loss) varied between 0.01 and 0.31 yr(-1). We measured 10 different chemical, anatomical, and morphological traits for all species. The species' average traits were useful predictors of wood decomposition rates, particularly the average diameter (dbh) of the tree species (R2 = 0.41). Lignin concentration further increased the proportion of explained inter-specific variation in wood decomposition (both negative relations, cumulative R2 = 0.55), although it did not significantly explain variation in wood decomposition rates if considered alone. When dbh values of the actual dead trees sampled for decomposition rate determination were used as a predictor variable, the final model (including dead tree dbh and lignin concentration) explained even more variation in wood decomposition rates (R2 = 0.71), underlining the importance of dbh in wood decomposition. Other traits, including wood density, wood anatomical traits, macronutrient concentrations, and the amount of phenolic extractives could not significantly explain the variation in wood decomposition rates. The surprising results of this multi-species study, in which for the first time a large set of traits is explicitly linked to wood decomposition rates, merits further testing in other forest ecosystems.

Estimating the effect of coppice practice on carbon dynamics of oak forests in Turkey

NASA Astrophysics Data System (ADS)

Lee, J.; Han, S. H.; Makineci, E.; Tolunay, D.; Son, Y.

2016-12-01

Coppice is a forest management practice, maximizing wood production by short-interval harvest. Coppice practice of oak forests in Turkey was abandoned in 2006, however, quantitative assessment to carbon (C) dynamics after the abandonment is still lacking. Accordingly, we simulated the annual changes in C stocks of oak forests in Turkey (7 regions) under the two management scenarios, using a forest C model (FBDC model): 200-year-interval harvest (A scenario) and abandonment of 20-year-interval coppice (B scenario). Growth of biomass was estimated by diameter at breast height (DBH) and allometric functions from previous studies. Survival of root and regeneration from sprout were formulated by a combination of empirical data and assumptions. Dead organic matter C dynamics were estimated by turnover (mortality) rates of biomass and decay rates of dead organic matter. The model estimates were verified by comparing the estimates and measured C stocks. Under the A scenario, the total (biomass, litter, dead wood, and mineral soil) C stock (Mg C ha-1) varied with stand age, ranging from 153.65 to 284.64. The total C stock (Mg C ha-1) started increasing rapidly after abandonment of coppice practice from 134.23 at 1 year to 280.71 at 200 year. The total C stock under the B scenario converged to the level of total C stock under the A scenario. After the abandonment of coppice practice, the C stocks of biomass, litter, and dead wood almost recovered in 30 years, however, the mineral soil C stock required longer time for recovery. This study was supported by Korea Ministry of Environment (2014001310008) and Korea Forest Service (S111314L100110).

Here Be Dragons: Effective (X-ray) Timing with the Cospectrum

NASA Astrophysics Data System (ADS)

Huppenkothen, Daniela; Bachetti, Matteo

2018-01-01

In recent years, the cross spectrum has received considerable attention as a means of characterising the variability of astronomical sources as a function of wavelength. While much has been written about the statistics of time and phase lags, the cospectrum—the real part of the cross spectrum—has only recently been understood as means of mitigating instrumental effects dependent on temporal frequency in astronomical detectors, as well as a method of characterizing the coherent variability in two wavelength ranges on different time scales. In this talk, I will present recent advances made in understanding the statistical properties of cospectra, leading to much improved inferences for periodic and quasi-periodic signals. I will also present a new method to reliably mitigate instrumental effects such as dead time in X-ray detectors, and show how we can use the cospectrum to model highly variable sources such as X-ray binaries or Active Galactic Nuclei.

The North Caucasus Insurgency: Dead or Alive

DTIC Science & Technology

2017-02-01

Shvedov, a liberal Rus- sian journalist and expert on the North Caucasus, stat- ed at the time that “the number of bombings , terrorist attacks and murders...crowded subway stations in Mos- cow were targeted by suicide bombers, resulting in 3 the deaths of 40 civilians. In January 2011, a bomb ex- ploded in...Moscow’s busy Domodedovo International Airport, leaving 37 dead. In 2013, three suicide bomb - ings on October 21, December 29, and December 30, shook

[Studies on the persistence of the infectivity of Trypanosoma cruzi. II. Persistence of infectivity of T. cruzi in dead bugs (author's transl)].

PubMed

Soares, V A; Marsden, P D

1979-12-01

Investigations into the viability time of T. cruzi in dead bugs experimentally infected with "Peru" strain showed a maximum of 9 days for Dipetalogaster maximus and 8 for Triatoma infestans maintained at ambient temperature (26 degrees C). On refrigeration survival was increased to 60 days. In routine xenodiagnosis in the refrigerator 90 day survival was noted of both T. cruzi and the vector bug.

Microbial nitrogen sinks in the water column of a large coastal hypoxic area, the Gulf of Mexico "Dead Zone"

NASA Astrophysics Data System (ADS)

Rogener, M. K.; Roberts, B. J.; Rabalais, N. N.; Stewart, F. J.; Joye, S. B.

2016-02-01

Excess nitrogen in coastal environments leads to eutrophication, harmful algal blooms, habitat loss, oxygen depletion and reductions in biodiversity. As such, biological nitrogen (N) removal through the microbially-mediated process of denitrification is a critical ecosystem function that can mitigate the negative consequences of excess nitrogen loading. However, denitrification can produce nitrous oxide, a potent greenhouse gas, as a byproduct under some environmental conditions. To understand how excess nitrogen loading impacts denitrification, we measured rates of this process in the water column of the Gulf of Mexico "Dead Zone" three times over the summer of 2015. The Dead Zone is generated by excessive nitrogen loading from the Mississippi River co-occurring with strong water column stratification, which leads to a large summer-time hypoxic/anoxic area at the mouth of the river and along the coast of Louisiana. Rates of denitrification ranged from 31 to 153 nmol L-1 d-1. Dead Zone waters are also enriched in methane and aerobic methane oxidation rates ranged from 0.1 to 4.3 nmol L-1 d-1. Maximal denitrification rates were observed at stations with the lowest oxygen concentrations and highest methane oxidation rates, suggesting a potential coupling between nitrate reduction and methane oxidation which both scrubs reactive N and methane from the system, thus performing a duel ecosystem service.

Comparison of burning characteristics of live and dead chaparral fuels

Treesearch

L. Sun; X. Zhou; S. Mahalingam; D.R. Weise

2006-01-01

Wildfire spread in living vegetation, such as chaparral in southern California, often causes significant damage to infrastructure and ecosystems. The effects of physical characteristics of fuels and fuel beds on live fuel burning and whether live fuels differ fundamentally from dead woody fuels in their burning characteristics are not well understood. Toward this end,...

Davis Fire: Fire behavior and fire effects analysis

Treesearch

LaWen T. Hollingsworth

2010-01-01

The Davis Fire presents an interesting example of fire behavior in subalpine fir, partially dead lodgepole pine with multiple age classes, and moist site Douglas-fir vegetation types. This has been summer of moderate temperatures and intermittent moisture that has kept live herbaceous and live woody moistures fairly high and dead fuel moistures at a moderate level....

Determination of power system component parameters using nonlinear dead beat estimation method

NASA Astrophysics Data System (ADS)

Kolluru, Lakshmi

Power systems are considered the most complex man-made wonders in existence today. In order to effectively supply the ever increasing demands of the consumers, power systems are required to remain stable at all times. Stability and monitoring of these complex systems are achieved by strategically placed computerized control centers. State and parameter estimation is an integral part of these facilities, as they deal with identifying the unknown states and/or parameters of the systems. Advancements in measurement technologies and the introduction of phasor measurement units (PMU) provide detailed and dynamic information of all measurements. Accurate availability of dynamic measurements provides engineers the opportunity to expand and explore various possibilities in power system dynamic analysis/control. This thesis discusses the development of a parameter determination algorithm for nonlinear power systems, using dynamic data obtained from local measurements. The proposed algorithm was developed by observing the dead beat estimator used in state space estimation of linear systems. The dead beat estimator is considered to be very effective as it is capable of obtaining the required results in a fixed number of steps. The number of steps required is related to the order of the system and the number of parameters to be estimated. The proposed algorithm uses the idea of dead beat estimator and nonlinear finite difference methods to create an algorithm which is user friendly and can determine the parameters fairly accurately and effectively. The proposed algorithm is based on a deterministic approach, which uses dynamic data and mathematical models of power system components to determine the unknown parameters. The effectiveness of the algorithm is tested by implementing it to identify the unknown parameters of a synchronous machine. MATLAB environment is used to create three test cases for dynamic analysis of the system with assumed known parameters. Faults are introduced in the virtual test systems and the dynamic data obtained in each case is analyzed and recorded. Ideally, actual measurements are to be provided to the algorithm. As the measurements are not readily available the data obtained from simulations is fed into the determination algorithm as inputs. The obtained results are then compared to the original (or assumed) values of the parameters. The results obtained suggest that the algorithm is able to determine the parameters of a synchronous machine when crisp data is available.

Monitoring of sinkholes and subsidence affecting the Jordanian coast of the Dead Sea through Synthetic Aperture Radar data and last generation Sentinel-1 data

NASA Astrophysics Data System (ADS)

Tessari, Giulia; Riccardi, Paolo; Lecci, Daniele; Pasquali, Paolo; Floris, Mario

2017-04-01

Since the mid-1980s the coast of the Dead Sea is affected by sinkholes occurring over and around the emerged mud and salt flats. Strong subsidence and landslides also affect some segments of the coast. Nowadays, several thousands of sinkholes attest that the degradation of the Dead Sea coast is worsening. Furthermore, soil deformations are interesting the main streets running along both the Israeli and Jordanian sides of the Dead Sea. These hazards are due to the dramatic dropping of the Dead Sea level, characterized by an increasing rate from about 60 cm/yr in the 1970s up to 1 m/yr in the 2000s, which provokes a lowering of the fresh-saline groundwater interface, replacing the hypersaline groundwater with fresh water and causing a consequent erosion of the subsurface salt layers. Subsidence, sinkholes, river erosion and landslides damage bridges, roads, dikes, houses, factories worsening this ongoing disaster. One of the most emblematic effects is the catastrophic collapse of a 12-km newly constructed dyke, located on the Lisan Peninsula (Jordan), occurred in 2000. Differential Interferometric Synthetic Aperture Radar (DInSAR) techniques and Advanced stacking DInSAR techniques (A-DInSAR) were applied to investigate sinkholes and subsidence affecting the Jordanian coast of the Dead Sea. The use of SAR data already proof to be efficient on the risk management of the area, allowing to identify a vulnerable portion of an Israeli highway, averting a possible collapse. Deformation analysis has been focused on the Ghor Al Haditha area and Lisan peninsula, located in the South-Eastern part of the lake coast. The availability of a huge database of SAR data, since the beginning of the 90s, allowed to observe the evolution of the displacements which are damaging this area. Furthermore, last generation Sentinel-1 data, acquired by the ESA mission, were processed to obtain information about the recent evolution of the subsidence and sinkholes affecting the study area, from the end of 2014 to the present. Important subsidence can be noticed mainly in correspondence of the emerging coast. Moreover, some solar evaporation pools used for salt production are injured by high deformations. Analysis of results obtained from SAR satellite data allows to identify different hazard processing affecting the study area and define the displacement time-series to clearly describe the evolution of the different phenomena, resulting as an effective tool to prevent damage and collapses. Furthermore, vulnerability maps can be created and possible precursor behaviour can be highlighted demonstrating the predictive capability of these data.

Solanaceae IV: Atropa belladonna, deadly nightshade.

PubMed

Lee, M R

2007-03-01

The Deadly Nightshade, Atropa belladonna, is a plant surrounded by myth, fear and awe. In antiquity, the Greeks and the Romans knew that it contained a deadly poison. In medieval times, it was widely used by witches, sorcerors and professional poisoners. Linnaeus later codified its remarkable properties as the genus Atropa, the Fate that slits the thin spun life and the species belladonna because of its power to dilate the pupils. In the 1830s, the pure alkaloid I-atropine was isolated from the plant. This proved to be a significant tool in the study of the autonomic nervous system leading to the identification of acetylcholine as an important neurotransmitter in mammals. When pure atropine became available, it caused a large number of deaths, whether by accident, suicide or homicide.

Measurement of temperature changes in cooling dead rats using magnetic resonance thermometry.

PubMed

Kuribayashi, Hideto; Cui, Fanlai; Hirakawa, Keiko; Kanawaku, Yoshimasa; Ohno, Youkichi

2011-11-01

Magnetic resonance imaging thermometry has been introduced as a technique for measurement of temperature changes in cooling dead rats. Rat pelvic magnetic resonance images were acquired sequentially more than 2h after euthanasia by halothane overdose. A series of temperature difference maps in cooling dead rats was obtained with calculating imaging phase changes induced by the water proton frequency shift caused by temperature changes. Different cooling processes were monitored by the temperature difference maps in the rats. Magnetic resonance imaging thermometry applied in the study of laboratory animals could theoretically reproduce a variety of causes of death with different environmental conditions. Outcomes from experimental animal studies could be translated into a temperature-based time of death estimation in forensics. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

9 CFR 82.6 - Interstate movement of dead birds and dead poultry from a quarantined area.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Interstate movement of dead birds and... (END) § 82.6 Interstate movement of dead birds and dead poultry from a quarantined area. (a) Except as provided in paragraph (b) of this section for dressed carcasses, dead birds and dead poultry, including any...

9 CFR 82.6 - Interstate movement of dead birds and dead poultry from a quarantined area.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Interstate movement of dead birds and... (END) § 82.6 Interstate movement of dead birds and dead poultry from a quarantined area. (a) Except as provided in paragraph (b) of this section for dressed carcasses, dead birds and dead poultry, including any...

Chip-Based Dynamic Real-Time Quantification of Drug-Induced Cytotoxicity in Human Tumor Cells

PubMed Central

Wlodkowic, Donald; Skommer, Joanna; McGuinness, Dagmara; Faley, Shannon; Kolch, Walter; Darzynkiewicz, Zbigniew; Cooper, Jonathan M.

2013-01-01

Cell cytotoxicity tests are among the most common bioassays using flow cytometry and fluorescence imaging analysis. The permeability of plasma membranes to charged fluorescent probes serves, in these assays, as a marker distinguishing live from dead cells. Since it is generally assumed that probes, such as propidium iodide (PI) or 7-amino-actinomycin D (7-AAD), are themselves cytotoxic, they are currently generally used only as the end-point markers of assays for live versus dead cells. In the current study, we provide novel insights into potential applications of these classical plasma membrane integrity markers in the dynamic tracking of drug-induced cytotoxicity. We show that treatment of a number of different human tumor cell lines in cultures for up to 72 h with the PI, 7-AAD, SYTOX Green (SY-G), SYTOX Red (SYR), TO-PRO, and YO-PRO had no effect on cell viability assessed by the integrity of plasma membrane, cell cycle progression, and rate of proliferation. We subsequently explore the potential of dynamic labeling with these markers in real-time analysis, by comparing results from both conventional cytometry and microfluidic chips. Considering the simplicity of the staining protocols and their low cost combined with the potential for real-time data collection, we show how that real-time fluorescent imaging and Lab-on-a-Chip platforms have the potential to be used for automated drug screening routines. PMID:19572560

Somatic survival and organ donation among brain-dead patients in the state of Qatar.

PubMed

George, Saibu; Thomas, Merlin; Ibrahim, Wanis H; Abdussalam, Ahmed; Chandra, Prem; Ali, Husain Shabbir; Raza, Tasleem

2016-10-31

The Qatari law, as in many other countries, uses brain death as the main criteria for organ donation and cessation of medical support. By contrast, most of the public in Qatar do not agree with the limitation or withdrawal of medical care until the time of cardiac death. The current study aims to examine the duration of somatic survival after brain death, organ donation rate in brain-dead patients as well as review the underlying etiologies and level of support provided in the state of Qatar. This is a retrospective study of all patients diagnosed with brain death over a 10-year period conducted at the largest tertiary center in Qatar (Hamad General Hospital). Among the 53 patients who were diagnosed with brain death during the study period, the median and mean somatic survivals of brain-dead patients in the current study were 3 and 4.5 days respectively. The most common etiology was intracranial hemorrhage (45.3 %) followed by ischemic stroke (17 %). Ischemic stroke patients had a median survival of 11 days. Organ donation was accepted by only two families (6.6 %) of the 30 brain dead patients deemed suitable for organ donation. The average somatic survival of brain-dead patients is less than one week irrespective of supportive measures provided. Organ donation rate was extremely low among brain-dead patients in Qatar. Improved public education may lead to significant improvement in resource utilization as well as organ transplant donors and should be a major target area of future health care policies.

Water input requirements of the rapidly shrinking Dead Sea

NASA Astrophysics Data System (ADS)

Abu Ghazleh, Shahrazad; Hartmann, Jens; Jansen, Nils; Kempe, Stephan

2009-05-01

The deepest point on Earth, the Dead Sea level, has been dropping alarmingly since 1978 by 0.7 m/a on average due to the accelerating water consumption in the Jordan catchment and stood in 2008 at 420 m below sea level. In this study, a terrain model of the surface area and water volume of the Dead Sea was developed from the Shuttle Radar Topography Mission data using ArcGIS. The model shows that the lake shrinks on average by 4 km2/a in area and by 0.47 km3/a in volume, amounting to a cumulative loss of 14 km3 in the last 30 years. The receding level leaves almost annually erosional terraces, recorded here for the first time by Differential Global Positioning System field surveys. The terrace altitudes were correlated among the different profiles and dated to specific years of the lake level regression, illustrating the tight correlation between the morphology of the terrace sequence and the receding lake level. Our volume-level model described here and previous work on groundwater inflow suggest that the projected Dead Sea-Red Sea channel or the Mediterranean-Dead Sea channel must have a carrying capacity of >0.9 km3/a in order to slowly re-fill the lake to its former level and to create a sustainable system of electricity generation and freshwater production by desalinization. Moreover, such a channel will maintain tourism and potash industry on both sides of the Dead Sea and reduce the natural hazard caused by the recession.

The relationship between tree growth patterns and likelihood of mortality: A study of two tree species in the Sierra Nevada

USGS Publications Warehouse

Das, A.J.; Battles, J.J.; Stephenson, N.L.; van Mantgem, P.J.

2007-01-01

We examined mortality of Abies concolor (Gord. & Glend.) Lindl. (white fir) and Pinus lambertiana Dougl. (sugar pine) by developing logistic models using three growth indices obtained from tree rings: average growth, growth trend, and count of abrupt growth declines. For P. lambertiana, models with average growth, growth trend, and count of abrupt declines improved overall prediction (78.6% dead trees correctly classified, 83.7% live trees correctly classified) compared with a model with average recent growth alone (69.6% dead trees correctly classified, 67.3% live trees correctly classified). For A. concolor, counts of abrupt declines and longer time intervals improved overall classification (trees with DBH ???20 cm: 78.9% dead trees correctly classified and 76.7% live trees correctly classified vs. 64.9% dead trees correctly classified and 77.9% live trees correctly classified; trees with DBH <20 cm: 71.6% dead trees correctly classified and 71.0% live trees correctly classified vs. 67.2% dead trees correctly classified and 66.7% live trees correctly classified). In general, count of abrupt declines improved live-tree classification. External validation of A. concolor models showed that they functioned well at stands not used in model development, and the development of size-specific models demonstrated important differences in mortality risk between understory and canopy trees. Population-level mortality-risk models were developed for A. concolor and generated realistic mortality rates at two sites. Our results support the contention that a more comprehensive use of the growth record yields a more robust assessment of mortality risk. ?? 2007 NRC.

Potential of Staphylococcus xylosus strain for recovering nickel ions from aqueous solutions

NASA Astrophysics Data System (ADS)

Al-Gheethi, A.; Efaq, A. N.; Mohamed, R. M.; Abdel-Monem, M.; Amir Hashim, M.

2017-10-01

The potential of bacterial biomass for the biosorption of heavy metals has investigated extensively. However, the bacterial species exhibited different affinities toward the heavy metals ions based on their differences in cell wall characteristics, structure and physiological status (living or dead cells). In this study, the potential of living and dead cells of Staphylococcus xylosus 222W for removal nickel ions from aqueous solution as a function for physiological status, nickel and biomass concentrations, time, pH and temperature was investigated. The pre-treatment of bacterial cells was performed by the heating at 100 °C for 15 min. The removal experiments were conducted in the lab scale. The results revealed that the dead cells exhibited more efficiency in removing nickel ions than living cells at all investigated concentrations (2 to 10 mM). The biosorption efficiency (E %) increased with increasing in biomass cells to limit concentrations (0.1 to 1 g dry wt L-1). The maximum removal of nickel was 81.41 vs. 77.10 % by living and dead cells, respectively achieved after 9 and 10 hrs of the incubation period, respectively. The acidic conditions decrease the efficiency of metal removal, while the optimal removal was recorded at pH 8 for both biomass (living and dead cells). The maximum uptake capacity of S. xylosus 222W (living and dead cells) was recorded at 37oC, the percentage removed being 75.90 vs. 84.92 %, respectively. It can be concluded that S. xylosus 222W exhibited high potential and affinity to remove of nickel ions from aqueous solution.

Designing primers and evaluation of the efficiency of propidium monoazide - Quantitative polymerase chain reaction for counting the viable cells of Lactobacillus gasseri and Lactobacillus salivarius.

PubMed

Lai, Chieh-Hsien; Wu, Sih-Rong; Pang, Jen-Chieh; Ramireddy, Latha; Chiang, Yu-Cheng; Lin, Chien-Ku; Tsen, Hau-Yang

2017-07-01

The purpose of this study is to evaluate the efficiency of using propidium monoazide (PMA) real-time quantitative polymerase chain reaction (qPCR) to count the viable cells of Lactobacillus gasseri and Lactobacillus salivarius in probiotic products. Based on the internal transcription spacer and 23S rRNA genes, two primer sets specific for these two Lactobacillus species were designed. For a probiotic product, the total deMan Rogosa Sharpe plate count was 8.65±0.69 log CFU/g, while for qPCR, the cell counts of L. gasseri and L. salivarius were 8.39±0.14 log CFU/g and 8.57±0.24 log CFU/g, respectively. Under the same conditions, for its heat-killed product, qPCR counts for L. gasseri and L. salivarius were 6.70±0.16 log cells/g and 7.67±0.20 log cells/g, while PMA-qPCR counts were 5.33±0.18 log cells/g and 5.05±0.23 log cells/g, respectively. For cell dilutions with a viable cell count of 8.5 log CFU/mL for L. gasseri and L. salivarius, after heat killing, the PMA-qPCR count for both Lactobacillus species was near 5.5 log cells/mL. When the PMA-qPCR counts of these cell dilutions were compared before and after heat killing, although some DNA might be lost during the heat killing, significant qPCR signals from dead cells, i.e., about 4-5 log cells/mL, could not be reduced by PMA treatment. Increasing PMA concentrations from 100 μM to 200 μM or light exposure time from 5 minutes to 15 minutes had no or, if any, only minor effect on the reduction of qPCR signals from their dead cells. Thus, to differentiate viable lactic acid bacterial cells from dead cells using the PMA-qPCR method, the efficiency of PMA to reduce the qPCR signals from dead cells should be notable. Copyright © 2016. Published by Elsevier B.V.

DEAD ZONE IN THE POLAR-CAP ACCELERATOR OF PULSARS

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

Chen, Alexander Y.; Beloborodov, Andrei M.

We study plasma flows above pulsar polar caps using time-dependent simulations of plasma particles in the self-consistent electric field. The flow behavior is controlled by the dimensionless parameter {alpha} = j/c{rho}{sub GJ}, where j is the electric current density and {rho}{sub GJ} is the Goldreich-Julian charge density. The region of the polar cap where 0 < {alpha} < 1 is a {sup d}ead zone{sup -}in this zone, particle acceleration is inefficient and pair creation is not expected even for young, rapidly rotating pulsars. Pulsars with polar caps near the rotation axis are predicted to have a hollow-cone structure of radiomore » emission, as the dead zone occupies the central part of the polar cap. Our results apply to charge-separated flows of electrons (j < 0) or ions (j > 0). In the latter case, we consider the possibility of a mixed flow consisting of different ion species, and observe the development of two-stream instability. The dead zone at the polar cap is essential for the development of an outer gap near the null surface {rho}{sub GJ} = 0.« less

A Final Approach Trajectory Model for Current Operations

NASA Technical Reports Server (NTRS)

Gong, Chester; Sadovsky, Alexander

2010-01-01

Predicting accurate trajectories with limited intent information is a challenge faced by air traffic management decision support tools in operation today. One such tool is the FAA's Terminal Proximity Alert system which is intended to assist controllers in maintaining safe separation of arrival aircraft during final approach. In an effort to improve the performance of such tools, two final approach trajectory models are proposed; one based on polynomial interpolation, the other on the Fourier transform. These models were tested against actual traffic data and used to study effects of the key final approach trajectory modeling parameters of wind, aircraft type, and weight class, on trajectory prediction accuracy. Using only the limited intent data available to today's ATM system, both the polynomial interpolation and Fourier transform models showed improved trajectory prediction accuracy over a baseline dead reckoning model. Analysis of actual arrival traffic showed that this improved trajectory prediction accuracy leads to improved inter-arrival separation prediction accuracy for longer look ahead times. The difference in mean inter-arrival separation prediction error between the Fourier transform and dead reckoning models was 0.2 nmi for a look ahead time of 120 sec, a 33 percent improvement, with a corresponding 32 percent improvement in standard deviation.

Sperm viability assessment in marine invertebrates by fluorescent staining and spectrofluorimetry: A promising tool for assessing marine pollution impact.

PubMed

Gallo, Alessandra; Boni, Raffaele; Tosti, Elisabetta

2018-01-01

The viability of spermatozoa is a crucial parameter to evaluate their quality that is an important issue in ecotoxicological studies. Here, a new method has been developed to rapidly determine the viability of spermatozoa in three marine invertebrates: the ascidian Ciona intestinalis, the sea urchin Paracentrotus lividus and the mollusc Mytilus galloprovincialis. This method employed the dual DNA fluorescent staining coupled with spectrofluorimetric analysis. The dual fluorescent staining used the SYBR-14 stained live spermatozoa and propidium iodide stained degenerated cells that had lost membrane integrity. Stain uptake was assessed by confocal microscopy and then the percentage of live and dead spermatozoa was quantified by spectrofluorimetric analysis. The microscopic examination revealed three populations of spermatozoa: living-SYBR-14 stained, dead-PI stained, and dying-doubly stained spermatozoa. The fluorescence emission peak values recorded in a spectrofluorimeter provide the portion of live and dead spermatozoa showing a significant negative correlation. The stain combination was further validated using known ratios of live and dead spermatozoa. The present study demonstrated that the dual DNA staining with SYBR-14 and propidium iodide was effective in assessing viability of spermatozoa in marine invertebrates and that spectrofluorimetric analysis can be successfully employed to evaluate the percentage of live and dead spermatozoa. The method develop herein is simple, accurate, rapid, sensitive, and cost-effective, so it could be a useful tool by which marine pollutants may be screened for spermiotoxicity. Copyright © 2017 Elsevier Inc. All rights reserved.

Comparison of immunohistochemistry and polymerase chain reaction for detection of West Nile virus in naturally infected dead birds.

PubMed

Sandhu, Tejbir; Sidhu, Dalbinder; Dhillon, Major; Fang, Ying

2010-10-04

Credible vector-borne disease surveillance programs, especially in developing countries with limited resources, must include diagnostic tests that are efficient, inexpensive and simple and safe to administer while maintaining high levels of sensitivity and specificity. Since immunohistochemistry (IHC) includes most of these features, its sensitivity, specificity, predictive positive value (PPV) and predictive negative value (PNV) for West Nile virus (WNv) screening were compared to those of the gold standard, RT-PCR testing of kidney tissue in dead birds. IHC and RT-PCR were performed for WNv antigen on 41 dead birds (belonging to five orders) collected from the northwest region of the Riverside County of California. Fixed tissue sections were screened by IHC using polyclonal antibodies, and frozen kidney tissues were tested with RT-PCR. Kidney screening with IHC showed sensitivity, specificity, PPV and NPV of 95.45%, 73.68%, 80.77% and 93.33%, respectively. Based on WNv screening of kidney tissue, IHC and RT-PCR were in agreement with 95.45% (21/22) for positive dead birds and were in 100% (22/22) agreement when multi-organ screening by IHC was performed. The present study showed that IHC is as equally effective as RT-PCR in screening for WNv in dead birds. Therefore, IHC can effectively serve as a competent screening technique for those disease surveillance agencies that lack expensive RT-PCR technology while promoting safer biohazardous conditions, except at the initial stage of tissue collection.

Effects of Small-Scale Dead Wood Additions on Beetles in Southeastern U.S

Treesearch

Kier D. Klepzig; Michael L. Ferro; Michael D. Ulyshen; Matthew L. Gimmel; Jolie B. Mahfouz; Allan E. Tiarks; Chris E. Carlton

2012-01-01

Pitfall traps were used to sample beetles (Coleoptera) in plots with or without inputs of dead loblolly pine (Pinus taeda L.) wood at four locations (Louisiana, Mississippi, North Carolina and Texas) on the coastal plain of the southeastern United States. The plots were established in 1998 and sampling took place in 1998, 1999, and 2002 (only 1998...

Determination of the Effects of Medium Composition on the Monochloramine Disinfection Kinetics of Nitrosomonas europaea by the Propidium Monoazide Quantitative PCR and Live/Dead BacLight Methods

EPA Science Inventory

Various media compositions (phosphate 1-50 mM; ionic strength 2.8-150 meq/L) significantly affected Nitrosomonas europaea monochloramine disinfection kinetics determined by Live/Dead BacLight (LD) and propidium monoazide quantitative PCR (PMA-qPCR) methods (lag coefficient 37-490...

Evaluation of a Dynamic Load Transfer Function Using Grassland Curing Data

Treesearch

Patricia L. Andrews; Stuart A.J. Anderson; Wendy R. Anderson

2006-01-01

Understanding and calculating fire behaviour in various fuel types is essential for effective fire management, including wildfire suppression and fuels management. Fire spread in grassland fuel is affected by the curing level, the amount of dead fuel expressed as a percentage of the total (live and dead fuel combined). The influence of live fuel is included in various...

National inventories of down and dead woody material forest carbon stocks in the United States: Challenges and opportunities

Treesearch

C.W. Woodall; L.S. Heath; J.E. Smith

2008-01-01

Concerns over the effect of greenhouse gases and consequent international agreements and regional/national programs have spurred the need for comprehensive assessments of forest ecosystem carbon stocks. Down and dead woody (DDW) materials are a substantial component of forest carbon stocks; however, few surveys of DDW carbon stocks have been conducted at national-...

Regional biomass stores and dynamics in forests of coastal Alaska

Treesearch

Mikhaill A. Yatskov; Mark E. Harmon; Olga N. Krankina; Tara M. Barrett; Kevin R. Dobelbower; Andrew N. Gray; Becky Fasth; Lori Trummer; Toni L. Hoyman; Chana M. Dudoit

2015-01-01

Coastal Alaska is a vast forested region (6.2 million ha) with the potential to store large amounts of carbon in live and dead biomass thus influencing continental and global carbon dynamics. The main objectives of this study were to assess regional biomass stores, examine the biomass partitioning between live and dead pools, and evaluate the effect of disturbance on...

Is the Great American Teacher Dead? Principles to Resurrect Meaningful, Effective, and Consciousness Raising Instruction

ERIC Educational Resources Information Center

Ivers, John J.

2012-01-01

A couple of decades ago, a visiting anthropologist agreed with some U.S. authors that the American intellectual on university campuses is basically dead and his/her demise is reflected in the superficial, boring, and uninspiring content to which students are exposed. More recent evidence indicates that things have not changed very much. In this…

Size-dependent control of colloid transport via solute gradients in dead-end channels

PubMed Central

Shin, Sangwoo; Um, Eujin; Sabass, Benedikt; Ault, Jesse T.; Rahimi, Mohammad; Warren, Patrick B.; Stone, Howard A.

2016-01-01

Transport of colloids in dead-end channels is involved in widespread applications including drug delivery and underground oil and gas recovery. In such geometries, Brownian motion may be considered as the sole mechanism that enables transport of colloidal particles into or out of the channels, but it is, unfortunately, an extremely inefficient transport mechanism for microscale particles. Here, we explore the possibility of diffusiophoresis as a means to control the colloid transport in dead-end channels by introducing a solute gradient. We demonstrate that the transport of colloidal particles into the dead-end channels can be either enhanced or completely prevented via diffusiophoresis. In addition, we show that size-dependent diffusiophoretic transport of particles can be achieved by considering a finite Debye layer thickness effect, which is commonly ignored. A combination of diffusiophoresis and Brownian motion leads to a strong size-dependent focusing effect such that the larger particles tend to concentrate more and reside deeper in the channel. Our findings have implications for all manners of controlled release processes, especially for site-specific delivery systems where localized targeting of particles with minimal dispersion to the nontarget area is essential. PMID:26715753

Removal of the Magnetic Dead Layer by Geometric Design

DOE PAGES

Guo, Er-jia; Roldan, Manuel; Charlton, Timothy R.; ...

2018-05-28

The proximity effect is used to engineer interface effects such as magnetoelectric coupling, exchange bias, and emergent interfacial magnetism. However, the presence of a magnetic “dead layer” adversely affects the functionality of a heterostructure. Here in this paper, it is shown that by utilizing (111) polar planes, the magnetization of a manganite ultrathin layer can be maintained throughout its thickness. Combining structural characterization, magnetometry measurements, and magnetization depth profiling with polarized neutron reflectometry, it is found that the magnetic dead layer is absent in the (111)-oriented manganite layers, however, it occurs in the films with other orientations. Quantitative analysis ofmore » local structural and elemental spatial evolutions using scanning transmission electron microscopy and electron energy loss spectroscopy reveals that atomically sharp interfaces with minimal chemical intermixing in the (111)-oriented superlattices. The polar discontinuity across the (111) interfaces inducing charge redistribution within the SrTiO 3 layers is suggested, which promotes ferromagnetism throughout the (111)-oriented ultrathin manganite layers. The approach of eliminating problematic magnetic dead layers by changing the crystallographic orientation suggests a conceptually useful recipe to engineer the intriguing physical properties of oxide interfaces, especially in low dimensionality.« less

Removal of the Magnetic Dead Layer by Geometric Design

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

Guo, Er-jia; Roldan, Manuel; Charlton, Timothy R.

The proximity effect is used to engineer interface effects such as magnetoelectric coupling, exchange bias, and emergent interfacial magnetism. However, the presence of a magnetic “dead layer” adversely affects the functionality of a heterostructure. Here in this paper, it is shown that by utilizing (111) polar planes, the magnetization of a manganite ultrathin layer can be maintained throughout its thickness. Combining structural characterization, magnetometry measurements, and magnetization depth profiling with polarized neutron reflectometry, it is found that the magnetic dead layer is absent in the (111)-oriented manganite layers, however, it occurs in the films with other orientations. Quantitative analysis ofmore » local structural and elemental spatial evolutions using scanning transmission electron microscopy and electron energy loss spectroscopy reveals that atomically sharp interfaces with minimal chemical intermixing in the (111)-oriented superlattices. The polar discontinuity across the (111) interfaces inducing charge redistribution within the SrTiO 3 layers is suggested, which promotes ferromagnetism throughout the (111)-oriented ultrathin manganite layers. The approach of eliminating problematic magnetic dead layers by changing the crystallographic orientation suggests a conceptually useful recipe to engineer the intriguing physical properties of oxide interfaces, especially in low dimensionality.« less

Protostellar Disk Evolution over Million-year Timescales with a Prescription for Magnetized Turbulence

NASA Astrophysics Data System (ADS)

Landry, Russell; Dodson-Robinson, Sarah E.; Turner, Neal J.; Abram, Greg

2013-07-01

Magnetorotational instability (MRI) is the most promising mechanism behind accretion in low-mass protostellar disks. Here we present the first analysis of the global structure and evolution of non-ideal MRI-driven T-Tauri disks on million-year timescales. We accomplish this in a 1+1D simulation by calculating magnetic diffusivities and utilizing turbulence activity criteria to determine thermal structure and accretion rate without resorting to a three-dimensional magnetohydrodynamical (MHD) simulation. Our major findings are as follows. First, even for modest surface densities of just a few times the minimum-mass solar nebula, the dead zone encompasses the giant planet-forming region, preserving any compositional gradients. Second, the surface density of the active layer is nearly constant in time at roughly 10 g cm-2, which we use to derive a simple prescription for viscous heating in MRI-active disks for those who wish to avoid detailed MHD computations. Furthermore, unlike a standard disk with constant-α viscosity, the disk midplane does not cool off over time, though the surface cools as the star evolves along the Hayashi track. Instead, the MRI may pile material in the dead zone, causing it to heat up over time. The ice line is firmly in the terrestrial planet-forming region throughout disk evolution and can move either inward or outward with time, depending on whether pileups form near the star. Finally, steady-state mass transport is an extremely poor description of flow through an MRI-active disk, as we see both the turnaround in the accretion flow required by conservation of angular momentum and peaks in \\dot{M}(R) bracketing each side of the dead zone. We caution that MRI activity is sensitive to many parameters, including stellar X-ray flux, grain size, gas/small grain mass ratio and magnetic field strength, and we have not performed an exhaustive parameter study here. Our 1+1D model also does not include azimuthal information, which prevents us from modeling the effects of Rossby waves.

PROTOSTELLAR DISK EVOLUTION OVER MILLION-YEAR TIMESCALES WITH A PRESCRIPTION FOR MAGNETIZED TURBULENCE

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

Landry, Russell; Dodson-Robinson, Sarah E.; Turner, Neal J.

2013-07-10

Magnetorotational instability (MRI) is the most promising mechanism behind accretion in low-mass protostellar disks. Here we present the first analysis of the global structure and evolution of non-ideal MRI-driven T-Tauri disks on million-year timescales. We accomplish this in a 1+1D simulation by calculating magnetic diffusivities and utilizing turbulence activity criteria to determine thermal structure and accretion rate without resorting to a three-dimensional magnetohydrodynamical (MHD) simulation. Our major findings are as follows. First, even for modest surface densities of just a few times the minimum-mass solar nebula, the dead zone encompasses the giant planet-forming region, preserving any compositional gradients. Second, themore » surface density of the active layer is nearly constant in time at roughly 10 g cm{sup -2}, which we use to derive a simple prescription for viscous heating in MRI-active disks for those who wish to avoid detailed MHD computations. Furthermore, unlike a standard disk with constant-{alpha} viscosity, the disk midplane does not cool off over time, though the surface cools as the star evolves along the Hayashi track. Instead, the MRI may pile material in the dead zone, causing it to heat up over time. The ice line is firmly in the terrestrial planet-forming region throughout disk evolution and can move either inward or outward with time, depending on whether pileups form near the star. Finally, steady-state mass transport is an extremely poor description of flow through an MRI-active disk, as we see both the turnaround in the accretion flow required by conservation of angular momentum and peaks in M-dot (R) bracketing each side of the dead zone. We caution that MRI activity is sensitive to many parameters, including stellar X-ray flux, grain size, gas/small grain mass ratio and magnetic field strength, and we have not performed an exhaustive parameter study here. Our 1+1D model also does not include azimuthal information, which prevents us from modeling the effects of Rossby waves.« less

Donor brain death predisposes human kidney grafts to a proinflammatory reaction after transplantation.

PubMed

de Vries, D K; Lindeman, J H N; Ringers, J; Reinders, M E J; Rabelink, T J; Schaapherder, A F M

2011-05-01

Donor brain death has profound effects on post-transplantation graft function and survival. We hypothesized that changes initiated in the donor influence the graft's response to ischemia and reperfusion. In this study, human brain dead donor kidney grafts were compared to living and cardiac dead donor kidney grafts. Pretransplant biopsies of brain dead donor kidneys contained notably more infiltrating T lymphocytes and macrophages. To assess whether the different donor conditions result in a different response to reperfusion, local cytokine release from the reperfused kidney was studied by measurement of paired arterial and renal venous blood samples. Reperfusion of kidneys from brain dead donors was associated with the instantaneous release of inflammatory cytokines, such as G-CSF, IL-6, IL-9, IL-16 and MCP-1. In contrast, kidneys from living and cardiac dead donors showed a more modest cytokine response with release of IL-6 and small amounts of MCP-1. In conclusion, this study shows that donor brain death initiates an inflammatory state of the graft with T lymphocyte and macrophage infiltration and massive inflammatory cytokine release upon reperfusion. These observations suggest that brain dead donors require a novel approach for donor pretreatment aimed at preventing this inflammatory response to increase graft survival. ©2011 The Authors Journal compilation©2011 The American Society of Transplantation and the American Society of Transplant Surgeons.

Air Gaps, Size Effect, and Corner-Turning in Ambient LX-17

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

Souers, P C; Hernandez, A; Cabacungan, C

2008-02-05

Various ambient measurements are presented for LX-17. The size (diameter) effect has been measured with copper and Lucite confinement, where the failure radii are 4.0 and 6.5 mm, respectively. The air well corner-turn has been measured with an LX-07 booster, and the dead-zone results are comparable to the previous TATB-boosted work. Four double cylinders have been fired, and dead zones appear in all cases. The steel-backed samples are faster than the Lucite-backed samples by 0.6 {micro}s. Bare LX-07 and LX-17 of 12.7 mm-radius were fired with air gaps. Long acceptor regions were used to truly determine if detonation occurred ormore » not. The LX-07 crossed at 10 mm with a slight time delay. Steady state LX-17 crossed at 3.5 mm gap but failed to cross at 4.0 mm. LX-17 with a 12.7 mm run after the booster crossed a 1.5 mm gap but failed to cross 2.5 mm. Timing delays were measured where the detonation crossed the gaps. The Tarantula model is introduced as embedded in 0 reactive flow JWL++ and Linked Cheetah V4, mostly at 4 zones/mm. Tarantula has four pressure regions: off, initiation, failure and detonation. The physical basis of the input parameters is considered.« less

Foraging behavior of pileated woodpeckers in partial cut and uncut bottomland hardwood forest

USGS Publications Warehouse

Newell, P.; King, Sammy L.; Kaller, Michael D.

2009-01-01

In bottomland hardwood forests, partial cutting techniques are increasingly advocated and used to create habitat for priority wildlife like Louisiana black bear (Ursus americanus luteolus), white-tailed deer (Odocoileus virginianus), and Neotropical migrants. Although partial cutting may be beneficial to some species, those that use dead wood may be negatively affected since large diameter and poor quality trees (deformed, moribund, or dead) are rare, but normally targeted for removal. On the other hand, partial cutting can create dead wood if logging slash is left on-site. We studied foraging behavior of pileated woodpeckers (Dryocopus pileatus) in one- and two-year-old partial cuts designed to benefit priority species and in uncut forest during winter, spring, and summer of 2006 and 2007 in Louisiana. Males and females did not differ in their use of tree species, dbh class, decay class, foraging height, use of foraging tactics or substrate types; however, males foraged on larger substrates than females. In both partial cut and uncut forest, standing live trees were most frequently used (83% compared to 14% for standing dead trees and 3% for coarse woody debris); however, dead trees were selected (i.e. used out of proportion to availability). Overcup oak (Quercus lyrata) and bitter pecan (Carya aquatica) were also selected and sugarberry (Celtis laevigata) avoided. Pileated woodpeckers selected trees >= 50 cm dbh and avoided trees in smaller dbh classes (10-20 cm). Density of selected foraging substrates was the same in partial cut and uncut forest. Of the foraging substrates, woodpeckers spent 54% of foraging time on live branches and boles, 37% on dead branches and boles, and 9% on vines. Of the foraging tactics, the highest proportion of foraging time was spent excavating (58%), followed by pecking (14%), gleaning (14%), scaling (7%), berry-eating (4%), and probing (3%). Woodpecker use of foraging tactics and substrates, and foraging height and substrate diameter did not differ between recent partial cut and uncut forest. Partial cutting designed to improve or maintain habitat for priority wildlife did not affect pileated woodpecker foraging behavior or availability of selected trees compared to uncut forest in the short term.

Foraging behavior of pileated woodpeckers in partial cut and uncut bottomland hardwood forest

USGS Publications Warehouse

Newell, P.; King, S.; Kaller, M.

2009-01-01

In bottomland hardwood forests, partial cutting techniques are increasingly advocated and used to create habitat for priority wildlife like Louisiana black bear (Ursus americanus luteolus), white-tailed deer (Odocoileus virginianus), and Neotropical migrants. Although partial cutting may be beneficial to some species, those that use dead wood may be negatively affected since large diameter and poor quality trees (deformed, moribund, or dead) are rare, but normally targeted for removal. On the other hand, partial cutting can create dead wood if logging slash is left on-site. We studied foraging behavior of pileated woodpeckers (Dryocopus pileatus) in one- and two-year-old partial cuts designed to benefit priority species and in uncut forest during winter, spring, and summer of 2006 and 2007 in Louisiana. Males and females did not differ in their use of tree species, dbh class, decay class, foraging height, use of foraging tactics or substrate types; however, males foraged on larger substrates than females. In both partial cut and uncut forest, standing live trees were most frequently used (83% compared to 14% for standing dead trees and 3% for coarse woody debris); however, dead trees were selected (i.e. used out of proportion to availability). Overcup oak (Quercus lyrata) and bitter pecan (Carya aquatica) were also selected and sugarberry (Celtis laevigata) avoided. Pileated woodpeckers selected trees ???50 cm dbh and avoided trees in smaller dbh classes (10-20 cm). Density of selected foraging substrates was the same in partial cut and uncut forest. Of the foraging substrates, woodpeckers spent 54% of foraging time on live branches and boles, 37% on dead branches and boles, and 9% on vines. Of the foraging tactics, the highest proportion of foraging time was spent excavating (58%), followed by pecking (14%), gleaning (14%), scaling (7%), berry-eating (4%), and probing (3%). Woodpecker use of foraging tactics and substrates, and foraging height and substrate diameter did not differ between recent partial cut and uncut forest. Partial cutting designed to improve or maintain habitat for priority wildlife did not affect pileated woodpecker foraging behavior or availability of selected trees compared to uncut forest in the short term. ?? 2009 Elsevier B.V.

Improvement of vitrification of in vitro produced buffalo embryos with special reference to sex ratio following vitrification

PubMed Central

Mahmoud, K. Gh. M; Scholkamy, T. H; Darwish, S. F

2015-01-01

Cryopreservation and sexing of embryos are integrated into commercial embryo transfer technologies. To improve the effectiveness of vitrification of in vitro produced buffalo embryos, two experiments were conducted. The first evaluated the effect of exposure time (2 and 3 min) and developmental stage (morula and blastocysts) on the viability and development of vitrified buffalo embryos. Morphologically normal embryos and survival rates (re-expansion) significantly increased when vitrified morulae were exposed for 2 min compared to 3 min (P<0.001). On the other hand, morphologically normal and survival rates of blastocysts significantly increased when exposed for 3 min compared to 2 min (P<0.001). However, there were no significant differences between the two developmental stages (morulae and blastocystes) in the percentages of morphologically normal embryos and re-expansion rates after a 24 h culture. The second experiment aimed to evaluate the effect of viability on the sex ratio of buffalo embryos after vitrification and whether male and female embryos survived vitrification differently. A total number of 61 blastocysts were vitrified for 3 min with the same cryoprotectant as experiment 1. Higher percentages of males were recorded for live as compared to dead embryos; however, this difference was not significant. In conclusion, the post-thaw survival and development of in vitro produced morulae and blastocysts were found to be affected by exposure time rather than developmental stage. Survivability had no significant effect on the sex ratio of vitrified blastocysts; nevertheless, the number of surviving males was higher than dead male embryos. PMID:27175197

Whale and dolphin behavioural responses to dead conspecifics.

PubMed

Bearzi, Giovanni; Kerem, Dan; Furey, Nathan B; Pitman, Robert L; Rendell, Luke; Reeves, Randall R

2018-06-01

The scientific study of death across animal taxa-comparative thanatology-investigates how animals respond behaviourally, physiologically and psychologically to dead conspecifics, and the processes behind such responses. Several species of cetaceans have been long known to care for, attend to, be aroused by, or show interest in dead or dying individuals. We investigated patterns and variation in cetacean responses to dead conspecifics across cetacean taxa based on a comprehensive literature review. We analysed 78 records reported between 1970 and 2016, involving 20 of the 88 extant cetacean species. We adopted a weighted comparative approach to take observation effort into account and found that odontocetes (toothed cetaceans) were much more likely than mysticetes (baleen whales) to attend to dead conspecifics. Dolphins (Delphinidae) had the greatest occurrence of attentive behaviour (92.3% of all records), with a weighed attendance index 18 times greater than the average of all other cetacean families. Two dolphin genera, Sousa and Tursiops, constituted 55.1% of all cetacean records (N=43) and showed the highest incidence of attentive behaviour. Results of analyses intended to investigate the reasons behind these differences suggested that encephalisation may be an important predictor, consistent with the "social brain" hypothesis. Among attending individuals or groups of known sex (N=28), the majority (75.0%) were adult females with dead calves or juveniles (possibly their own offspring, with exceptions), consistent with the strong mother-calf bond, or, in a few cases, with the bond between mothers and other females in the group. The remaining records (25.0%) involved males either showing sexual interest in a dead adult or subadult, or carrying a dead calf in the presence of females. Because an inanimate individual is potentially rescuable, responses to dead conspecifics-especially by females-can be explained at least in part by attempts to revive and protect, having a clear adaptive value. In some cases such responses are followed by apparently maladaptive behaviour such as the long-term carrying of, or standing by, a decomposed carcass, similar to observations of certain terrestrial mammals. Among the possible explanations for the observed cetacean behavioural responses to dead conspecifics are strong attachment resulting in a difficulty of "letting go"-possibly related to grieving-or perhaps individuals failing to recognise or accept that an offspring or companion has died. Our current understanding is challenged by small sample size, incomplete descriptions, and lack of information on the physiology and neural processes underpinning the observed behaviour. We provide research recommendations that would improve such understanding. Copyright © 2018 Elsevier GmbH. All rights reserved.

Dreissenid mussels are not a "dead end" in Great Lakes food webs

USGS Publications Warehouse

Madenijan, Charles P.; Pothoven, Steven A.; Schneeberger, Philip J.; Ebener, Mark P.; Mohr, Lloyd C.; Nalepa, Thomas F.; Bence, James R.

2010-01-01

Dreissenid mussels have been regarded as a “dead end” in Great Lakes food webs because the degree of predation on dreissenid mussels, on a lakewide basis, is believed to be low. Waterfowl predation on dreissenid mussels in the Great Lakes has primarily been confined to bays, and therefore its effects on the dreissenid mussel population have been localized rather than operating on a lakewide level. Based on results from a previous study, annual consumption of dreissenid mussels by the round goby (Neogobius melanostomus) population in central Lake Erie averaged only 6 kilotonnes (kt; 1 kt = one thousand metric tons) during 1995–2002. In contrast, our coupling of lake whitefish (Coregonus clupeaformis) population models with a lake whitefish bioenergetics model revealed that lake whitefish populations in Lakes Michigan and Huron consumed 109 and 820 kt, respectively, of dreissenid mussels each year. Our results indicated that lake whitefish can be an important predator on dreissenid mussels in the Great Lakes, and that dreissenid mussels do not represent a “dead end” in Great Lakes food webs. The Lake Michigan dreissenid mussel population has been estimated to be growing more than three times faster than the Lake Huron dreissenid mussel population during the 2000s. One plausible explanation for the higher population growth rate in Lake Michigan would be the substantially higher predation rate by lake whitefish on dreissenid mussels in Lake Huron.

Self-Interaction Chromatography of mAbs: Accurate Measurement of Dead Volumes.

PubMed

Hedberg, S H M; Heng, J Y Y; Williams, D R; Liddell, J M

2015-12-01

Measurement of the second virial coefficient B22 for proteins using self-interaction chromatography (SIC) is becoming an increasingly important technique for studying their solution behaviour. In common with all physicochemical chromatographic methods, measuring the dead volume of the SIC packed column is crucial for accurate retention data; this paper examines best practise for dead volume determination. SIC type experiments using catalase, BSA, lysozyme and a mAb as model systems are reported, as well as a number of dead column measurements. It was observed that lysozyme and mAb interacted specifically with Toyopearl AF-Formyl dead columns depending upon pH and [NaCl], invalidating their dead volume usage. Toyopearl AF-Amino packed dead columns showed no such problems and acted as suitable dead columns without any solution condition dependency. Dead volume determinations using dextran MW standards with protein immobilised SIC columns provided dead volume estimates close to those obtained using Toyopearl AF-Amino dead columns. It is concluded that specific interactions between proteins, including mAbs, and select SIC support phases can compromise the use of some standard approaches for estimating the dead volume of SIC columns. Two other methods were shown to provide good estimates for the dead volume.

A percolation approach to study the high electric field effect on electrical conductivity of insulating polymer

NASA Astrophysics Data System (ADS)

Benallou, Amina; Hadri, Baghdad; Martinez-Vega, Juan; El Islam Boukortt, Nour

2018-04-01

The effect of percolation threshold on the behaviour of electrical conductivity at high electric field of insulating polymers has been briefly investigated in literature. Sometimes the dead ends links are not taken into account in the study of the electric field effect on the electrical properties. In this work, we present a theoretical framework and Monte Carlo simulation of the behaviour of the electric conductivity at high electric field based on the percolation theory using the traps energies levels which are distributed according to distribution law (uniform, Gaussian, and power-law). When a solid insulating material is subjected to a high electric field, and during trapping mechanism the dead ends of traps affect with decreasing the electric conductivity according to the traps energies levels, the correlation length of the clusters, the length of the dead ends, and the concentration of the accessible positions for the electrons. A reasonably good agreement is obtained between simulation results and the theoretical framework.

VHDL implementation of feature-extraction algorithm for the PANDA electromagnetic calorimeter

NASA Astrophysics Data System (ADS)

Guliyev, E.; Kavatsyuk, M.; Lemmens, P. J. J.; Tambave, G.; Löhner, H.; Panda Collaboration

2012-02-01

A simple, efficient, and robust feature-extraction algorithm, developed for the digital front-end electronics of the electromagnetic calorimeter of the PANDA spectrometer at FAIR, Darmstadt, is implemented in VHDL for a commercial 16 bit 100 MHz sampling ADC. The source-code is available as an open-source project and is adaptable for other projects and sampling ADCs. Best performance with different types of signal sources can be achieved through flexible parameter selection. The on-line data-processing in FPGA enables to construct an almost dead-time free data acquisition system which is successfully evaluated as a first step towards building a complete trigger-less readout chain. Prototype setups are studied to determine the dead-time of the implemented algorithm, the rate of false triggering, timing performance, and event correlations.

RTSJ Memory Areas and Their Affects on the Performance of a Flight-Like Attitude Control System

NASA Technical Reports Server (NTRS)

Niessner, Albert F.; Benowitz, Edward G.

2003-01-01

The two most important factors in improving performance in any software system, but especially a real-time, embedded system, are knowing which components are the low performers and knowing what can be done to improve their performance. The word performance with respect to a real-time, embedded system does not necessarily mean fast execution, which is the common definition when discussing non real-time systems. It also includes meeting all of the specified execution dead-lines and executing at the correct time without sacrificing non real-time performance. Using a Java prototype of an existing control system used on Deep Space 1[1], the effects from adding memory areas are measured and evaluated with respect to improving performance.

Effect of sampling volume on dry powder inhaler (DPI)-emitted aerosol aerodynamic particle size distributions (APSDs) measured by the Next-Generation Pharmaceutical Impactor (NGI) and the Andersen eight-stage cascade impactor (ACI).

PubMed

Mohammed, Hlack; Roberts, Daryl L; Copley, Mark; Hammond, Mark; Nichols, Steven C; Mitchell, Jolyon P

2012-09-01

Current pharmacopeial methods for testing dry powder inhalers (DPIs) require that 4.0 L be drawn through the inhaler to quantify aerodynamic particle size distribution of "inhaled" particles. This volume comfortably exceeds the internal dead volume of the Andersen eight-stage cascade impactor (ACI) and Next Generation pharmaceutical Impactor (NGI) as designated multistage cascade impactors. Two DPIs, the second (DPI-B) having similar resistance than the first (DPI-A) were used to evaluate ACI and NGI performance at 60 L/min following the methodology described in the European and United States Pharmacopeias. At sampling times ≥2 s (equivalent to volumes ≥2.0 L), both impactors provided consistent measures of therapeutically important fine particle mass (FPM) from both DPIs, independent of sample duration. At shorter sample times, FPM decreased substantially with the NGI, indicative of incomplete aerosol bolus transfer through the system whose dead space was 2.025 L. However, the ACI provided consistent measures of both variables across the range of sampled volumes evaluated, even when this volume was less than 50% of its internal dead space of 1.155 L. Such behavior may be indicative of maldistribution of the flow profile from the relatively narrow exit of the induction port to the uppermost stage of the impactor at start-up. An explanation of the ACI anomalous behavior from first principles requires resolution of the rapidly changing unsteady flow and pressure conditions at start up, and is the subject of ongoing research by the European Pharmaceutical Aerosol Group. Meanwhile, these experimental findings are provided to advocate a prudent approach by retaining the current pharmacopeial methodology.

Driving at Night Can Be Deadly

DOT National Transportation Integrated Search

1996-06-17

Efficient Commercial Vehicle Operations (CVO) is imperative as manufacturers and distributors move to new technologies, faster production methods and "Just in Time" delivery. CVO must offer more reliable travel times, as well as safety and flexibilit...

49 CFR 236.55 - Dead section; maximum length.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Dead section; maximum length. 236.55 Section 236... Instructions: All Systems Track Circuits § 236.55 Dead section; maximum length. Where dead section exceeds 35... over such dead section is less than 35 feet, the maximum length of the dead section shall not exceed...

49 CFR 236.55 - Dead section; maximum length.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 4 2014-10-01 2014-10-01 false Dead section; maximum length. 236.55 Section 236... Instructions: All Systems Track Circuits § 236.55 Dead section; maximum length. Where dead section exceeds 35... over such dead section is less than 35 feet, the maximum length of the dead section shall not exceed...

9 CFR 82.12 - Other interstate movements and special permits.

Code of Federal Regulations, 2014 CFR

2014-01-01

... for the disposal of dead birds or dead poultry that are infected with Newcastle disease, or dead birds or dead poultry from flocks infected with Newcastle disease, or manure generated by or eggs from... following: (i) The address of the place where the dead birds, dead poultry, manure, or eggs are located; and...

49 CFR 236.55 - Dead section; maximum length.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Dead section; maximum length. 236.55 Section 236... Instructions: All Systems Track Circuits § 236.55 Dead section; maximum length. Where dead section exceeds 35... over such dead section is less than 35 feet, the maximum length of the dead section shall not exceed...

49 CFR 236.55 - Dead section; maximum length.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 4 2013-10-01 2013-10-01 false Dead section; maximum length. 236.55 Section 236... Instructions: All Systems Track Circuits § 236.55 Dead section; maximum length. Where dead section exceeds 35... over such dead section is less than 35 feet, the maximum length of the dead section shall not exceed...

49 CFR 236.55 - Dead section; maximum length.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 4 2012-10-01 2012-10-01 false Dead section; maximum length. 236.55 Section 236... Instructions: All Systems Track Circuits § 236.55 Dead section; maximum length. Where dead section exceeds 35... over such dead section is less than 35 feet, the maximum length of the dead section shall not exceed...

Assessing the living and dead proportions of cold-water coral colonies: implications for deep-water Marine Protected Area monitoring in a changing ocean.

PubMed

Vad, Johanne; Orejas, Covadonga; Moreno-Navas, Juan; Findlay, Helen S; Roberts, J Murray

2017-01-01

Coral growth patterns result from an interplay of coral biology and environmental conditions. In this study colony size and proportion of live and dead skeletons in the cold-water coral (CWC) Lophelia pertusa (Linnaeus, 1758) were measured using video footage from Remotely Operated Vehicle (ROV) transects conducted at the inshore Mingulay Reef Complex (MRC) and at the offshore PISCES site (Rockall Bank) in the NE Atlantic. The main goal of this paper was to explore the development of a simple method to quantify coral growth and its potential application as an assessment tool of the health of these remote habitats. Eighteen colonies were selected and whole colony and dead/living layer size were measured. Live to dead layer ratios for each colony were then determined and analysed. The age of each colony was estimated using previously published data. Our paper shows that: (1) two distinct morphotypes can be described: at the MRC, colonies displayed a 'cauliflower-shaped' morphotype whereas at the PISCES site, colonies presented a more flattened 'bush-shaped' morphotype; (2) living layer size was positively correlated with whole colony size; (3) live to dead layer ratio was negatively correlated to whole colony size; (4) live to dead layer ratio never exceeded 0.27. These results suggest that as a colony develops and its growth rate slows down, the proportion of living polyps in the colony decreases. Furthermore, at least 73% of L. pertusa colonies are composed of exposed dead coral skeleton, vulnerable to ocean acidification and the associated shallowing of the aragonite saturation horizon, with significant implications for future deep-sea reef framework integrity. The clear visual contrast between white/pale living and grey/dark dead portions of the colonies also gives a new way by which they can be visually monitored over time. The increased use of marine autonomous survey vehicles offers an important new platform from which such a surveying technique could be applied to monitor deep-water marine protected areas in the future.

The effect of cortisol in rat steatotic and non-steatotic liver transplantation from brain-dead donors.

PubMed

Jiménez-Castro, Mónica B; Negrete-Sánchez, Elsa; Casillas-Ramírez, Araní; Gulfo, Jose; Álvarez-Mercado, Ana I; Cornide-Petronio, María Eugenia; Gracia-Sancho, Jordi; Rodés, Juan; Peralta, Carmen

2017-04-25

In the present study, we examined the effects of cortisol on steatotic and non-steatotic liver grafts from brain-dead donors and characterized the underlying mechanisms involved. Non-steatotic liver grafts showed reduced cortisol and increased cortisone levels in association with up-regulation of enzymes that inactivate cortisol. Conversely, steatotic liver grafts exhibited increased cortisol and reduced cortisone levels. The enzymes involved in cortisol generation were overexpressed, and those involved in cortisol inactivation or clearance were down-regulated in steatotic liver grafts. Exogenous administration of cortisol negatively affected hepatic damage and survival rate in non-steatotic liver transplantation (LT); however, cortisol treatment up-regulated the phosphoinositide 3-kinase (PI3K)-protein kinase C (PKC) pathway, resulting in protection against the deleterious effects of brain-dead donors on damage and inflammatory response in steatotic LT as well as in increased survival of recipients. The present study highlights the differences in the role of cortisol and hepatic mechanisms that regulate cortisol levels based on the type of liver. Our findings suggest that cortisol treatment is a feasible and highly protective strategy to reduce the adverse effects of brain-dead donor livers in order to ultimately improve liver graft quality in the presence of steatosis, whereas cortisol treatment would not be recommended for non-steatotic liver grafts. © 2017 The Author(s). published by Portland Press Limited on behalf of the Biochemical Society.

Assessment and management of dead-wood habitat

USGS Publications Warehouse

Hagar, Joan

2007-01-01

The Bureau of Land Management (BLM) is in the process of revising its resource management plans for six districts in western and southern Oregon as the result of the settlement of a lawsuit brought by the American Forest Resource Council. A range of management alternatives is being considered and evaluated including at least one that will minimize reserves on O&C lands. In order to develop the bases for evaluating management alternatives, the agency needs to derive a reasonable range of objectives for key issues and resources. Dead-wood habitat for wildlife has been identified as a key resource for which decision-making tools and techniques need to be refined and clarified. Under the Northwest Forest Plan, reserves were to play an important role in providing habitat for species associated with dead wood (U.S. Department of Agriculture Forest Service and U.S. Department of the Interior Bureau of Land Management, 1994). Thus, the BLM needs to: 1) address the question of how dead wood will be provided if reserves are not included as a management strategy in the revised Resource Management Plan, and 2) be able to evaluate the effects of alternative land management approaches. Dead wood has become an increasingly important conservation issue in managed forests, as awareness of its function in providing wildlife habitat and in basic ecological processes has dramatically increased over the last several decades (Laudenslayer et al., 2002). A major concern of forest managers is providing dead wood habitat for terrestrial wildlife. Wildlife in Pacific Northwest forests have evolved with disturbances that create large amounts of dead wood; so, it is not surprising that many species are closely associated with standing (snags) or down, dead wood. In general, the occurrence or abundance of one-quarter to one-third of forest-dwelling vertebrate wildlife species, is strongly associated with availability of suitable dead-wood habitat (Bunnell et al., 1999; Rose et al., 2001). In Oregon and Washington, approximately 150 species of wildlife are reported to use dead wood in forests (O’Neil et al., 2001). Forty-seven sensitive and special-status species are associated with dead wood (Appendix A). These are key species for management consideration because concern over small or declining populations is often related to loss of suitable dead-wood habitat (Marshall et al., 1996). Primary excavators (woodpeckers) also are often the focus of dead-wood management, because they perform keystone functions in forest ecosystems by creating cavities for secondary cavity-nesters (Martin and Eadie, 1999; Aubry and Raley, 2002). A diverse guild of secondary cavity-users (including swallows, bluebirds, several species of ducks and owls, ash-throated flycatcher, flying squirrel, bats, and many other species) is unable to excavate dead wood, and therefore relies on cavities created by woodpeckers for nesting sites. Suitable nest cavities are essential for reproduction, and their availability limits population size (Newton, 1994). Thus, populations of secondary cavity-nesters are tightly linked to the habitat requirements of primary excavators. Although managers often focus on decaying wood as habitat for wildlife, the integral role dead wood plays in ecological processes is an equally important consideration for management. Rose et al. (2001) provide a thorough review of the ecological functions of dead wood in Pacific Northwest forests, briefly summarized here. Decaying wood functions in: soil development and productivity, nutrient cycling, nitrogen fixation, and carbon storage. From ridge tops, to headwater streams, to estuaries and coastal marine ecosystems, decaying wood is fundamental to diverse terrestrial and aquatic food webs. Wildlife species that use dead wood for cover or feeding are linked to these ecosystem processes through a broad array of functional roles, including facilitation of decay and trophic interactions with other organisms (Marcot, 2002; Marcot, 2003). For example, by puncturing bark and fragmenting sapwood, woodpeckers create sites favorable for wood-decaying organisms (Farris et al., 2004), which in turn create habitat for other species and facilitate nutrient cycling. Small mammals that use down wood for cover function in the dispersal of plant seeds and fungal spores (Carey et al., 1999). Resident cavitynesting birds may regulate insect populations by preying on overwintering arthropods (Jackson, 1979; Kroll and Fleet, 1979). These examples illustrate how dead wood not only directly provides habitat for a large number of wildlife species, but also forms the foundation of functional webs that critically influence forest ecosystems (Marcot, 2002; Marcot, 2003). The important and far-reaching implications of management of decaying wood highlight the need for conservation of dead-wood resources in managed forests. Consideration of the key ecological functions of species associated with dead wood can help guide management of dead wood in a framework consistent with the paradigm of ecosystem management (Marcot and Vander Heyden, 2001; Marcot, 2002.) As more information is revealed about the ecological and habitat values of decaying wood, concern has increased over a reduction in the current amounts of dead wood relative to historic levels (Ohmann and Waddell, 2002). Past management practices have tended to severely reduce amounts of dead wood throughout all stages of forest development (Hansen et al., 1991). The large amounts of legacy wood that characterize young post-disturbance forests are not realized in managed stands, because most of the wood volume is removed at harvest for economic and safety reasons. Mid-rotation thinning is used to “salvage” some mortality that might otherwise occur due to suppression, so fewer snags are recruited in mid-seral stages. Harvest rotations of 80 years or less truncate tree size in managed stands, and thus limit the production of large-diameter wood. As a consequence of these practices, dead wood has been reduced by as much as 90% after two rotations of managed Douglas-fir (Rose et al., 2001). Large legacy deadwood is becoming a scarce, critical habitat that will take decades to centuries to replace. Furthermore, management continues to have important direct and indirect effects on the amount and distribution of dead wood in forests. Current guidelines for managing dead wood may be inadequate to maintain habitat for all associated species because they largely focus on a single use of dead wood (nesting habitat) by a small suite of species (cavity-nesting birds), and may under represent the sizes and amounts of dead wood used by many wildlife species (Rose et al., 2001, Wilhere, 2003). 

Abrupt aridities in the Levant-Sahel linked with solar activities

NASA Astrophysics Data System (ADS)

Stein, M.; Kushnir, Y.

2012-04-01

Observations of 19th and 20th century precipitation in the Dead Sea watershed region display a multidecadal, anti-phase relationship to North Atlantic (NAtl) sea surface temperature (SST) variability, such that when the NAtl is relatively cold, Jerusalem experiences higher than normal precipitation and vice versa. This association is underlined by a negative correlation to precipitation in the sub-Saharan Sahel and a positive correlation to precipitation in western North America, areas that are also affected by multidecadal NAtl SST variability. These observations are consistent with broad range of Holocene hydroclimatic fluctuations from the epochal, to the millennial and centennial time scales, as displayed by the Dead Sea and Sahelian lake levels and by direct and indirect proxy indicators of NAtl SSTs. On the epochal time scale, the gradual cooling of NAtl SSTs throughout the Holocene in response to precession-driven reduction of summer insolation is associated with previously well-studied wet-to-dry transition in the Sahel and with a general increase in Dead Sea lake levels from low stands after the Younger Dryas to higher stands in the mid- to late-Holocene. On the millennial and centennial time scales there is also evidence for an antiphase relationship between Holocene variations in the Dead Sea and Sahelian lake levels and with proxy indicators of NAtl SSTs. However, the records are punctuated by abrupt lake-level drops and extensive expansion of the desert belt at ~8.1, 5.7, 3.3 and 1.4 ka cal BP, which appear to be in-phase and which occur during previously documented abrupt major cooling events in the Northern Hemisphere. We link these cooling to solar activity variations that were identified in the North Atlantic IRD and cosmogenic isotopes records.

Understanding the effect of corticosteroid pretreatment in brain-dead organ donors: new mechanistic insights for improvement of organ quality in liver transplantation.

PubMed

Dahrenmöller, Carola; Reding, Raymond

2017-09-15

Transplant surgeons are currently faced with the challenge to accept marginal liver transplants due to steatosis or old age. Improving organ quality by implementing a selective organ protective donor management could be the first step towards a graft of enhanced quality. However, the molecular mechanisms of such treatments are still poorly understood. Glucocorticoid medication in donor medicine has been carried out and discussed for a long time. In a recent study published in Clinical Science , Jiménez-Castro et al. [Clin. Sci. (2017) 131, 733-746] demonstrate how liver histology and transplant liver function can be improved by administration of glucocorticoids to brain-dead donor rats with steatotic livers. This work illustrates the need for further trials in order to selectively improve the quality of steatotic livers with a potential for liver transplantation. © 2017 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

Comparison of live and dead molluscan assemblages suggests recent human-driven decline in benthic diversity in Phetchaburi (NW Gulf of Thailand)

NASA Astrophysics Data System (ADS)

Negri, Mauro Pietro; Sanfilippo, Rossana; Basso, Daniela; Rosso, Antonietta

2015-12-01

Dead and live molluscan assemblages from the coastal area of Phetchaburi (NW Gulf of Thailand) were compared by means of multivariate analysis. Seven thanatofacies were recognized, thriving in the area after the 1960s. Five of them, scattered along the tidal flat, represent oligotypic intertidal biotopes linked to a variety of environmental factors; the remaining two mirror high-diversity infralittoral associations. Conversely, only two poor, ill-defined biofacies thrive at present between the intertidal and the shallow infralittoral zones, somewhat resembling two of the thanatofacies. Diversity indexes reveal a dramatic biodiversity decline occurred from the 1960s onwards, far beyond the effects of time-averaging and accumulation. The responsibility for this reduction is largely attributable to the high impact of human activities, such as the intensive sea bottom trawling, the wastewaters from aquaculture (shrimp and fish ponds) and dense coastal villages, and, at a minor extent, the digging of edible molluscs from the tidal flat.

Biosorption of Cd(II) by live and dead cells of Bacillus cereus RC-1 isolated from cadmium-contaminated soil.

PubMed

Huang, Fei; Dang, Zhi; Guo, Chu-Ling; Lu, Gui-Ning; Gu, Roy R; Liu, Hong-Juan; Zhang, Hui

2013-07-01

The present study investigated the biosorption capacity of live and dead cells of Bacillus cereus RC-1 for Cd(II). The biosorption characteristics were investigated as a function of initial pH, contact time, and initial cadmium concentration. Equilibrium biosorption was modeled using Langmuir, Freundlich and Redlich-Peterson isotherm equations. It was found that the maximum biosorption capacities calculated from Langmuir isotherm were 31.95 mg/g and 24.01 mg/g for dead cells and live cells, respectively. The kinetics of the biosorption was better described by pseudo-second order kinetic model. Desorption efficiency of biosorbents was investigated at various pH values. These results indicated that dead cells have higher Cd(II) biosorption capacity than live cells. Furthermore, zeta potential, transmission electron microscopy (TEM), scanning electron microscopy (SEM) coupled with energy dispersive X-ray (EDX), and Fourier transform infrared spectroscopy (FTIR) studies were carried out to understand the differences in the Cd(II) biosorption behavior for the both biosorbents. The bioaccumulation of Cd(II) by B. cereus RC-1 was found to depend largely on extracellular biosorption rather than intracellular accumulation. Based on the above studies, dead biomass appears to be a more efficient biosorbent for the removal of Cd(II) from aqueous solution. Copyright © 2013 Elsevier B.V. All rights reserved.

Bacteria associated with decomposing dead wood in a natural temperate forest.

PubMed

Tláskal, Vojtech; Zrustová, Petra; Vrška, Tomáš; Baldrian, Petr

2017-12-01

Dead wood represents an important pool of organic matter in forests and is one of the sources of soil formation. It has been shown to harbour diverse communities of bacteria, but their roles in this habitat are still poorly understood. Here, we describe the bacterial communities in the dead wood of Abies alba, Picea abies and Fagus sylvatica in a temperate natural forest in Central Europe. An analysis of environmental factors showed that decomposing time along with pH and water content was the strongest drivers of community composition. Bacterial biomass positively correlated with N content and increased with decomposition along with the concurrent decrease in the fungal/bacterial biomass ratio. Rhizobiales and Acidobacteriales were abundant bacterial orders throughout the whole decay process, but many bacterial taxa were specific either for young (<15 years) or old dead wood. During early decomposition, bacterial genera able to fix N2 and to use simple C1 compounds (e.g. Yersinia and Methylomonas) were frequent, while wood in advanced decay was rich in taxa typical of forest soils (e.g. Bradyrhizobium and Rhodoplanes). Although the bacterial contribution to dead wood turnover remains unclear, the community composition appears to reflect the changing conditions of the substrate and suggests broad metabolic capacities of its members. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Evolution of genomic diversity and sex at extreme environments: Fungal life under hypersaline Dead Sea stress

PubMed Central

Kis-Papo, Tamar; Kirzhner, Valery; Wasser, Solomon P.; Nevo, Eviatar

2003-01-01

We have found that genomic diversity is generally positively correlated with abiotic and biotic stress levels (1–3). However, beyond a high-threshold level of stress, the diversity declines to a few adapted genotypes. The Dead Sea is the harshest planetary hypersaline environment (340 g·liter–1 total dissolved salts, ≈10 times sea water). Hence, the Dead Sea is an excellent natural laboratory for testing the “rise and fall” pattern of genetic diversity with stress proposed in this article. Here, we examined genomic diversity of the ascomycete fungus Aspergillus versicolor from saline, nonsaline, and hypersaline Dead Sea environments. We screened the coding and noncoding genomes of A. versicolor isolates by using >600 AFLP (amplified fragment length polymorphism) markers (equal to loci). Genomic diversity was positively correlated with stress, culminating in the Dead Sea surface but dropped drastically in 50- to 280-m-deep seawater. The genomic diversity pattern paralleled the pattern of sexual reproduction of fungal species across the same southward gradient of increasing stress in Israel. This parallel may suggest that diversity and sex are intertwined intimately according to the rise and fall pattern and adaptively selected by natural selection in fungal genome evolution. Future large-scale verification in micromycetes will define further the trajectories of diversity and sex in the rise and fall pattern. PMID:14645702

Effect of dead layer and strain on diffuse phase transition of PLZT relaxor thin films.

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

Tong, S.; Narayanan, M.; Ma, B.

2011-02-01

Bulk relaxor ferroelectrics exhibit excellent permittivity compared to their thin film counterpart, although both show diffuse phase transition (DPT) behavior unlike normal ferroelectrics. To better understand the effect of dead layer and strain on the observed anomaly in the dielectric properties, we have developed relaxor PLZT (lead lanthanum zirconate titanate) thin films with different thicknesses and measured their dielectric properties as a function of temperature and frequency. The effect of dead layer on thin film permittivity has been found to be independent of temperature and frequency, and is governed by the Schottky barrier between the platinum electrode and PLZT. Themore » total strain (thermal and intrinsic) in the film majorly determines the broadening, dielectric peak and temperature shift in the relaxor ferroelectric. The Curie-Weiss type law for relaxors has been further modified to incorporate these two effects to accurately predict the DPT behavior of thin film and bulk relaxor ferroelectrics. The dielectric behavior of thin film is predicted by using the bulk dielectric data from literature in the proposed equation, which agree well with the measured dielectric behavior.« less

9 CFR 82.12 - Other interstate movements and special permits.

Code of Federal Regulations, 2012 CFR

2012-01-01

... required for the disposal of dead birds or dead poultry that are infected with END, or dead birds or dead..., the special permit will also include the following: (i) The address of the place where the dead birds, dead poultry, manure, or eggs are located; and (ii) The number and type of birds, poultry, or other...

9 CFR 82.12 - Other interstate movements and special permits.

Code of Federal Regulations, 2010 CFR

2010-01-01

... required for the disposal of dead birds or dead poultry that are infected with END, or dead birds or dead..., the special permit will also include the following: (i) The address of the place where the dead birds, dead poultry, manure, or eggs are located; and (ii) The number and type of birds, poultry, or other...

9 CFR 82.12 - Other interstate movements and special permits.

Code of Federal Regulations, 2013 CFR

2013-01-01

... required for the disposal of dead birds or dead poultry that are infected with END, or dead birds or dead..., the special permit will also include the following: (i) The address of the place where the dead birds, dead poultry, manure, or eggs are located; and (ii) The number and type of birds, poultry, or other...

9 CFR 82.12 - Other interstate movements and special permits.

Code of Federal Regulations, 2011 CFR

2011-01-01

... required for the disposal of dead birds or dead poultry that are infected with END, or dead birds or dead..., the special permit will also include the following: (i) The address of the place where the dead birds, dead poultry, manure, or eggs are located; and (ii) The number and type of birds, poultry, or other...

Towards the establishment of a general rate law for gypsum nucleation

NASA Astrophysics Data System (ADS)

Reznik, Itay J.; Ganor, Jiwchar; Gruber, Chen; Gavrieli, Ittai

2012-05-01

Gypsum nucleation kinetics from a wide range of chemical compositions (1.45 < Ca2+/SO42- < 115), ionic strengths (I = 2.5-10 m) and saturation state with respect to gypsum (Ωgyp = 1.07-8.4) were examined in batch experiments containing mixtures of Ca2+-rich Dead Sea brine and SO42-rich seawater with or without addition of extra Na2SO4 and CaCl2·2H2O. The induction times attained in the present study were compiled together with literature values from experiments carried out under significantly different conditions (synthetic NaCl solutions; I = 0.09-6.3 m; Ca2+/SO42- = 1; Ωgyp:1.59-7.76). Despite the variability in the experimental solutions, a single rate law based on classic nucleation theory was formulated to describe the induction times from more than 80 experiments: logT=log{1}/{3.17·Cs·exp{-}7.08ln2Ω}+0.072·Cs·exp-{1.426}/{ln2Ω} where Tind is the induction time, Cs is the solubility of gypsum and Ω is the saturation state with respect to gypsum. The rate law provides Tind for gypsum precipitation from aqueous solutions at 25 °C, containing no synthetic antiscalants or catalysts, within a 95% confidence interval within a factor of 5. Based on this rate law, we show that at present most of the precipitation of gypsum from the Dead Sea brine occurs following significant evaporation in the industrial evaporation ponds and not in the Dead Sea itself. Whereas Tind in Dead Sea brines is very long (on the order of 3 years), the evaporation of brine in the industrial ponds leads to increased Ω values, and thus to short Tind in the order of a few days. However, if seawater or reject brine from seawater desalinization will be introduced to the Dead Sea to restore its declining level, Tind will be significantly reduced and gypsum nucleation and precipitation will occur. For evaporated seawater, the proposed rate law predicts that even though saturation is obtained when seawater is evaporated by a factor of 2.8, gypsum will nucleate at reasonable times (few years) only when seawater are evaporated by a factor of ˜3.3.

Adaptive Fuzzy Control for Nonstrict Feedback Systems With Unmodeled Dynamics and Fuzzy Dead Zone via Output Feedback.

PubMed

Wang, Lijie; Li, Hongyi; Zhou, Qi; Lu, Renquan

2017-09-01

This paper investigates the problem of observer-based adaptive fuzzy control for a category of nonstrict feedback systems subject to both unmodeled dynamics and fuzzy dead zone. Through constructing a fuzzy state observer and introducing a center of gravity method, unmeasurable states are estimated and the fuzzy dead zone is defuzzified, respectively. By employing fuzzy logic systems to identify the unknown functions. And combining small-gain approach with adaptive backstepping control technique, a novel adaptive fuzzy output feedback control strategy is developed, which ensures that all signals involved are semi-globally uniformly bounded. Simulation results are given to demonstrate the effectiveness of the presented method.

Effect of baffle spacing and baffle cut on thermal-hydraulic characteristics of the fluid flow

NASA Astrophysics Data System (ADS)

Chernyateva, R. R.

2018-01-01

This article presents the results of investigations of the influence of baffle spacing and baffle cut on the size of dead zone formed near the cross baffles using numerical simulation methods. It is showed the structure of an additional baffle plate which can be used to reduce the dead zone and smoother flow distribution over the cross section.

A dual near-infrared and dielectric spectroscopies strategy to monitor populations of Chinese hamster ovary cells in bioreactor.

PubMed

Courtès, Franck; Ebel, Bruno; Guédon, Emmanuel; Marc, Annie

2016-05-01

to develop a new strategy combining near-infrared (NIR) and dielectric spectroscopies for real-time monitoring and in-depth characterizing populations of Chinese hamster ovary cells throughout cultures performed in bioreactors. Spectral data processing was based on off-line analyses of the cells, including trypan blue exclusion method, and lactate dehydrogenase activity (LDH). Viable cell density showed a linear correlation with permittivity up to 6 × 10(6) cells ml(-1), while a logarithmic correlation was found between non-lysed dead cell density and conductivity up to 10(7) cells ml(-1). Additionally, partial least square technique was used to develop a calibration model of the supernatant LDH activity based on online NIR spectra with a RMSEC of 55 U l(-1). Considering the LDH content of viable cells measured to be 110 U per 10(9) cells, the lysed dead cell density could be then estimated. These calibration models provided real-time prediction accuracy (R(2) ≥ 0.95) for the three types of cell populations. The high potential of a dual spectroscopy strategy to enhance the online bioprocesses characterization is demonstrated since it allows the simultaneous determination of viable, dead and lysed cell populations in real time.

SlDEAD31, a Putative DEAD-Box RNA Helicase Gene, Regulates Salt and Drought Tolerance and Stress-Related Genes in Tomato.

PubMed

Zhu, Mingku; Chen, Guoping; Dong, Tingting; Wang, Lingling; Zhang, Jianling; Zhao, Zhiping; Hu, Zongli

2015-01-01

The DEAD-box RNA helicases are involved in almost every aspect of RNA metabolism, associated with diverse cellular functions including plant growth and development, and their importance in response to biotic and abiotic stresses is only beginning to emerge. However, none of DEAD-box genes was well characterized in tomato so far. In this study, we reported on the identification and characterization of two putative DEAD-box RNA helicase genes, SlDEAD30 and SlDEAD31 from tomato, which were classified into stress-related DEAD-box proteins by phylogenetic analysis. Expression analysis indicated that SlDEAD30 was highly expressed in roots and mature leaves, while SlDEAD31 was constantly expressed in various tissues. Furthermore, the expression of both genes was induced mainly in roots under NaCl stress, and SlDEAD31 mRNA was also increased by heat, cold, and dehydration. In stress assays, transgenic tomato plants overexpressing SlDEAD31 exhibited dramatically enhanced salt tolerance and slightly improved drought resistance, which were simultaneously demonstrated by significantly enhanced expression of multiple biotic and abiotic stress-related genes, higher survival rate, relative water content (RWC) and chlorophyll content, and lower water loss rate and malondialdehyde (MDA) production compared to wild-type plants. Collectively, these results provide a preliminary characterization of SlDEAD30 and SlDEAD31 genes in tomato, and suggest that stress-responsive SlDEAD31 is essential for salt and drought tolerance and stress-related gene regulation in plants.

North Atlantic influence on 19th-20th century rainfall in the Dead Sea watershed, teleconnections with the Sahel, and implication for Holocene climate fluctuations

NASA Astrophysics Data System (ADS)

Kushnir, Yochanan; Stein, Mordechai

2010-12-01

The importance of understanding processes that govern the hydroclimate of the Mediterranean Basin is highlighted by the projected significant drying of the region in response to the increase in greenhouse gas concentrations. Here we study the long-term hydroclimatic variability of the central Levant region, situated in the eastern boundary of the Basin, as reveled by instrumental observations and the Holocene record of Dead Sea level variations. Observations of 19th and 20th century precipitation in the Dead Sea watershed region display a multidecadal, anti-phase relationship to North Atlantic (NAtl) sea surface temperature (SST) variability, such that when the NAtl is relatively cold, Jerusalem experiences higher than normal precipitation and vice versa. This association is underlined by a negative correlation to precipitation in the sub-Saharan Sahel and a positive correlation to precipitation in western North America, areas that are also affected by multidecadal NAtl SST variability. These observations are consistent with a broad range of Holocene hydroclimatic fluctuations from the epochal, to the millennial and centennial time scales, as displayed by the Dead Sea lake level, by lake levels in the Sahel, and by direct and indirect proxy indicators of NAtl SSTs. On the epochal time scale, the gradual cooling of NAtl SSTs throughout the Holocene in response to precession-driven reduction of summer insolation is associated with previously well-studied wet-to-dry transition in the Sahel and with a general increase in Dead Sea lake levels from low stands after the Younger Dryas to higher stands in the mid- to late-Holocene. On the millennial and centennial time scales there is also evidence for an anti-phase relationship between Holocene variations in the Dead Sea and Sahelian lake levels and with proxy indicators of NAtl SSTs. However the records are punctuated by abrupt lake-level drops, which appear to be in-phase and which occur during previously documented abrupt major cooling events in the Northern Hemisphere. We propose that the mechanisms by which NAtl SSTs affect precipitation in the central Levant is related to the tendency for high (low) pressure anomalies to persist over the eastern North Atlantic/Western Mediterranean region when the Basin is cold (warm). This, in turn, affects the likelihood of cold air outbreaks and cyclogenesis in the Eastern Mediterranean and, consequently, rainfall in the central Levant region. Depending on its phase, this natural mechanism can alleviate or exacerbate the anthropogenic impact on the regions' hydroclimatic future.

Biological legacies buffer local species extinction after logging

PubMed Central

Rudolphi, Jörgen; Jönsson, Mari T; Gustafsson, Lena

2014-01-01

Clearcutting has been identified as a main threat to forest biodiversity. In the last few decades, alternatives to clearcutting have gained much interest. Living and dead trees are often retained after harvest to serve as structural legacies to mitigate negative effects of forestry. However, this practice is widely employed without information from systematic before–after control-impact studies to assess the processes involved in species responses after clearcutting with retention. We performed a large-scale survey of the occurrence of logging-sensitive and red-listed bryophytes and lichens before and after clearcutting with the retention approach. A methodology was adopted that, for the first time in studies on retention approaches, enabled monitoring of location-specific substrates. We used uncut stands as controls to assess the variables affecting the survival of species after a major disturbance. In total, 12 bryophyte species and 27 lichen species were analysed. All were classified as sensitive to logging, and most species are also currently red-listed. We found that living and dead trees retained after final harvest acted as refugia in which logging-sensitive species were able to survive for 3 to 7 years after logging. Depending on type of retention and organism group, between 35% and 92% of the species occurrences persisted on retained structures. Most species observed outside retention trees or patches disappeared. Larger pre-harvest population sizes of bryophytes on dead wood increased the survival probability of the species and hence buffered the negative effects of logging. Synthesis and applications. Careful spatial planning of retention structures is required to fully embrace the habitats of logging-sensitive species. Bryophytes and lichens persisted to a higher degree in retention patches compared to solitary trees or in the clearcut area. Retaining groups of trees in logged areas will help to sustain populations of species over the clearcut phase. When possible, old logs should be moved into retention patches to provide a more beneficial environment for dead wood-dependent species. Our study also highlights the need for more before–after control-impact studies of retention forestry to explore factors influencing the survival of species after logging. PMID:25653456

Biological legacies buffer local species extinction after logging.

PubMed

Rudolphi, Jörgen; Jönsson, Mari T; Gustafsson, Lena; Bugmann, H

2014-02-01

Clearcutting has been identified as a main threat to forest biodiversity. In the last few decades, alternatives to clearcutting have gained much interest. Living and dead trees are often retained after harvest to serve as structural legacies to mitigate negative effects of forestry. However, this practice is widely employed without information from systematic before-after control-impact studies to assess the processes involved in species responses after clearcutting with retention. We performed a large-scale survey of the occurrence of logging-sensitive and red-listed bryophytes and lichens before and after clearcutting with the retention approach. A methodology was adopted that, for the first time in studies on retention approaches, enabled monitoring of location-specific substrates. We used uncut stands as controls to assess the variables affecting the survival of species after a major disturbance. In total, 12 bryophyte species and 27 lichen species were analysed. All were classified as sensitive to logging, and most species are also currently red-listed. We found that living and dead trees retained after final harvest acted as refugia in which logging-sensitive species were able to survive for 3 to 7 years after logging. Depending on type of retention and organism group, between 35% and 92% of the species occurrences persisted on retained structures. Most species observed outside retention trees or patches disappeared. Larger pre-harvest population sizes of bryophytes on dead wood increased the survival probability of the species and hence buffered the negative effects of logging. Synthesis and applications . Careful spatial planning of retention structures is required to fully embrace the habitats of logging-sensitive species. Bryophytes and lichens persisted to a higher degree in retention patches compared to solitary trees or in the clearcut area. Retaining groups of trees in logged areas will help to sustain populations of species over the clearcut phase. When possible, old logs should be moved into retention patches to provide a more beneficial environment for dead wood-dependent species. Our study also highlights the need for more before-after control-impact studies of retention forestry to explore factors influencing the survival of species after logging.

A new modelling and identification scheme for time-delay systems with experimental investigation: a relay feedback approach

NASA Astrophysics Data System (ADS)

Pandey, Saurabh; Majhi, Somanath; Ghorai, Prasenjit

2017-07-01

In this paper, the conventional relay feedback test has been modified for modelling and identification of a class of real-time dynamical systems in terms of linear transfer function models with time-delay. An ideal relay and unknown systems are connected through a negative feedback loop to bring the sustained oscillatory output around the non-zero setpoint. Thereafter, the obtained limit cycle information is substituted in the derived mathematical equations for accurate identification of unknown plants in terms of overdamped, underdamped, critically damped second-order plus dead time and stable first-order plus dead time transfer function models. Typical examples from the literature are included for the validation of the proposed identification scheme through computer simulations. Subsequently, the comparisons between estimated model and true system are drawn through integral absolute error criterion and frequency response plots. Finally, the obtained output responses through simulations are verified experimentally on real-time liquid level control system using Yokogawa Distributed Control System CENTUM CS3000 set up.

Combating the Reliability Challenge of GPU Register File at Low Supply Voltage

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

Tan, Jingweijia; Song, Shuaiwen; Yan, Kaige

Supply voltage reduction is an effective approach to significantly reduce GPU energy consumption. As the largest on-chip storage structure, the GPU register file becomes the reliability hotspot that prevents further supply voltage reduction below the safe limit (Vmin) due to process variation effects. This work addresses the reliability challenge of the GPU register file at low supply voltages, which is an essential first step for aggressive supply voltage reduction of the entire GPU chip. We propose GR-Guard, an architectural solution that leverages long register dead time to enable reliable operations from unreliable register file at low voltages.

Ultraviolet radiation properties as applied to photoclimatherapy at the Dead Sea.

PubMed

Kudish, A I; Abels, D; Harari, M

2003-05-01

The Dead Sea basin, the lowest terrestrial point on earth, is recognized as a natural treatment center for patients with various cutaneous and rheumatic diseases. Psoriasis is the major skin disease treated at the Dead Sea with excellent improvement to complete clearance exceeding 85% after 4 weeks of treatment. These results were postulated to be associated with a unique spectrum of ultraviolet radiation present in the Dead Sea area. The UVB and UVA radiation at two sites is measured continuously by identical sets of broad-band Solar Light Co. Inc. meters (Philadelphia, PA). The spectral selectivity within the UVB and UVA spectrum was determined using a narrow-band spectroradiometer, UV-Optronics 742 (Orlando, FL). The optimum exposure time intervals for photoclimatherapy, defined as the minimum ratio of erythema to therapeutic radiation intensities, were also determined using a Solar Light Co. Inc. Microtops II, Ozone Monitor-Sunphotometer. The ultraviolet radiation at the Dead Sea is attenuated relative to Beer Sheva as a result of the increased optical path length and consequent enhanced scattering. The UVB radiation is attenuated to a greater extent than UVA and the shorter erythema UVB spectral range decreased significantly compared with the longer therapeutic UVB wavelengths. It was demonstrated that the relative attenuation within the UVB spectral range is greatest for the shorter erythema rays and less for the longer therapeutic UVB wavelengths, thus producing a greater proportion of the longer therapeutic UVB wavelengths in the ultraviolet spectrum. These measurements can be utilized to minimize the exposure to solar radiation by correlating the cumulative UVB radiation dose to treatment efficacy and by formulating a patient sun exposure treatment protocol for Dead Sea photoclimatherapy.

Effect of Cypermethrin on the Growth of Ciliate Protozoan Paramecium caudatum.

PubMed

Dutta, Joydeep

2015-01-01

The objective of this study is to assess the effect of cypermethrin on the growth of ciliate protozoan Paramecium caudatum. Monoxenic culture of P. caudatum, were exposed to different doses (0.01, 0.05, 0.1, 0.15, and 0.2 µg/L) of cypermethrin along with control for 24, 48, 72, and 96 h time interval. The total numbers of live and dead cells were counted after trypan blue staining in Neubauer hemocytometer. Marked decrease in the number of living cells with the increase in the concentration of cypermethrin and with increasing exposure time intervals was recorded. The results indicate that cypermethrin is toxic to P. caudatum even at low concentrations when it enters in the aquatic system through runoff.

9 CFR 82.6 - Interstate movement of dead birds and dead poultry from a quarantined area.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Interstate movement of dead birds and dead poultry from a quarantined area. 82.6 Section 82.6 Animals and Animal Products ANIMAL AND PLANT... (END) § 82.6 Interstate movement of dead birds and dead poultry from a quarantined area. (a) Except as...

9 CFR 82.6 - Interstate movement of dead birds and dead poultry from a quarantined area.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Interstate movement of dead birds and dead poultry from a quarantined area. 82.6 Section 82.6 Animals and Animal Products ANIMAL AND PLANT... movement of dead birds and dead poultry from a quarantined area. (a) Except as provided in paragraph (b) of...

9 CFR 82.6 - Interstate movement of dead birds and dead poultry from a quarantined area.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 9 Animals and Animal Products 1 2013-01-01 2013-01-01 false Interstate movement of dead birds and dead poultry from a quarantined area. 82.6 Section 82.6 Animals and Animal Products ANIMAL AND PLANT... (END) § 82.6 Interstate movement of dead birds and dead poultry from a quarantined area. (a) Except as...

California Drought Effects on Sierra Trees Mapped by NASA

NASA Image and Video Library

2016-06-27

California, reveals the devastating effect of California's ongoing drought on Sierra Nevada conifer forests. The map will be used to help the U.S. Forest Service assess and respond to the impacts of increased tree mortality caused by the drought, particularly where wildlands meet urban areas within the Sierra National Forest. After several years of extreme drought, the highly stressed conifers (trees or bushes that produce cones and are usually green year-round) of the Sierra Nevada are now more susceptible to bark beetles (Dendroctonus spp.). While bark beetles killing trees in the Sierra Nevada is a natural phenomenon, the scale of mortality in the last couple of years is far greater than previously observed. The U.S. Forest Service is using recent airborne spectroscopic measurements from NASA's Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) instrument aboard NASA's ER-2 aircraft, together with new advanced algorithms, to quantify this impact over this large region of rugged terrain. The high-altitude ER-2 aircraft is based at NASA's Armstrong Flight Research Center, Edwards, California. The image was created by scientists at the USFS's Pacific Southwest Region Remote Sensing Lab, McClellan, California, by performing a time series analysis of AVIRIS images. Scientists evaluated baseline tree mortality on public lands in the summer of 2015 using a machine learning algorithm called "random forest." This algorithm classifies the AVIRIS measurements as dominated by either shrubs, healthy trees or newly dead conifer trees. To quantify how much the amount of dead vegetation increased during the fall of 2015, the Forest Service scientists conducted an advanced spectral mixture analysis. This analysis evaluates each spectrum to determine the fraction of green vegetation, dead vegetation and soil. The full spectral range of AVIRIS is important to separate the signatures of soil and dead vegetation. To produce this comprehensive Sierra National Forest tree mortality map, the result from the summer of 2015 was evaluated to look for increases of more than 10 percent in dead vegetation during the fall of 2015. AVIRIS measures spectra of the Earth system to conduct advanced science research. These western U.S. AVIRIS measurements were acquired as part of NASA's Hyperspectral Infrared Imager (HyspIRI) preparatory airborne campaign. HyspIRI was one of the space missions suggested to NASA by the National Academy of Sciences in its 2007 decadal survey for Earth Science. In the future, HyspIRI could provide spectral and thermal measurements of this type globally for ecosystem research and additional science objectives. http://photojournal.jpl.nasa.gov/catalog/PIA20717

In vivo wound healing activity and phytochemical screening of the crude extract and various fractions of Kalanchoe petitiana A. Rich (Crassulaceae) leaves in mice.

PubMed

Mekonnen, Awol; Sidamo, Temesgen; Asres, Kaleab; Engidawork, Ephrem

2013-01-30

The leaves of Kalanchoe petitiana A. Rich (Crassulaceae) are used in Ethiopian folk medicine for treatment of evil eye, fractured surface for bone setting and several skin disorders including for the treatment of sores, boils, and malignant wounds. In order to scientifically prove the claimed utilization of the plant, the effects of the extracts and the fractions were investigated using in vivo excision, incision and dead space wound models. Mice were used for wound healing study, while rats and rabbit were used for skin irritation test. For studying healing activity 80% methanolic extract and the fractions were formulated in strength of 5% and 10%, either as ointment (hydroalcoholic extract, aqueous and methanol fractions) or gel (chloroform fraction). Oral administration of the crude extract was used for dead space model. Negative controls were treated either with simple ointment or sodium carboxyl methyl cellulose xerogel, while positive controls with nitrofurazone (0.2 w/v) skin ointment. Negative controls for dead space model were treated with 1% carboxy methyl cellulose. Parameters, including rate of wound contraction, period of complete epithelializtion, hydroxyproline contents and skin breaking strength were evaluated. Significant wound healing activity was observed with ointment formulated from the crude extract at both 5% and 10% concentration (p<0.01) compared to controls in both excision and incision models. In dead space model, 600 mg/kg (p<0.01) but not 300 mg/kg significantly increased hydroxyproline content. Fractions showed variable effect, with the chloroform fraction lacking any significant effect. Both 5% and 10% formulations of the aqueous and methanolic fractions significantly increased wound contraction, decreased epithelializtion time and increased hydroxyproline content in excision wound model (p<0.05) as compared to controls. These fractions were also endowed with higher skin breaking strength in incision wound model (p<0.01). The present study provided evidence that the leaves of Kalanchoe petitiana A. Rich possess remarkable wound healing activities supporting the folkloric assertion of the plant. Fractionation revealed that polar or semi polar compound may play vital role, as both aqueous and methanolic fractions were endowed with wound healing activity. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Lung Focused Resuscitation at a Specialized Donor Care Facility Improves Lung Procurement Rates.

PubMed

Chang, Stephanie H; Kreisel, Daniel; Marklin, Gary F; Cook, Lindsey; Hachem, Ramsey; Kozower, Benjamin D; Balsara, Keki R; Bell, Jennifer M; Frederiksen, Christine; Meyers, Bryan F; Patterson, G Alexander; Puri, Varun

2018-05-01

Lung procurement for transplantation occurs in approximately 20% of brain dead donors and is a major impediment to wider application of lung transplantation. We investigated the effect of lung protective management at a specialized donor care facility on lung procurement rates from brain dead donors. Our local organ procurement organization instituted a protocol of lung protective management at a freestanding specialized donor care facility in 2008. Brain dead donors from 2001 to 2007 (early period) were compared with those from 2009 to 2016 (current period) for lung procurement rates and other solid-organ procurement rates using a prospectively maintained database. An overall increase occurred in the number of brain dead donors during the study period (early group, 791; late group, 1,333; p < 0.0001). The lung procurement rate (lung donors/all brain dead donors) improved markedly after the introduction of lung protective management (early group, 157 of 791 [19.8%]; current group, 452 of 1,333 [33.9%]; p < 0.0001). The overall organ procurement rate (total number of organs procured/donor) also increased during the study period (early group, 3.5 organs/donor; current group, 3.8 organs/donor; p = 0.006). Lung protective management in brain dead donors at a specialized donor care facility is associated with higher lung utilization rates compared with conventional management. This strategy does not adversely affect the utilization of other organs in a multiorgan donor. Copyright © 2018 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Effect of Insulin Therapy using Hyper-insulinemic Normoglycemic Clamp on Inflammatory Response in Brain Dead Organ Donors.

PubMed

Aljiffry, M; Hassanain, M; Schricker, T; Shaheen, M; Nouh, T; Lattermann, R; Salman, A; Wykes, L; Metrakos, P

2016-05-01

Brain death is a major stress that is associated with a massive inflammatory response and systemic hyperglycemia. Severe inflammation leads to increased graft immunogenicity and risk of graft dysfunction; while acute hyperglycemia aggravates the inflammatory response and increases the risk of morbidity and mortality. Insulin therapy not only controls hyperglycemia but also suppresses inflammation. The present study is to investigate the anti-inflammatory properties and the normoglycemia maintenance of high dose insulin on brain dead organ donors. 15 brain dead organ donors were divided into 2 groups, insulin treated (n=6) and controls (n=9). Insulin was provided for a minimum of 6 h using the hyperinsulinemic normoglycemic clamp technique. The changes of serum cytokines, including IL-6, IL-10, IL-1β, IL-8, TNFα, TGFα and MCP-1, were measured by suspension bead array immunoassay and glucose by a glucose monitor. Compared to controls, insulin treated donors had a significant lower blood glucose 4.8 (4-6.9) vs. 9 (5.6-11.7) mmol/L, p<0.01); the net decreases of pro-inflammatory cytokines, such as IL-6 and MCP-1, and the net increase of anti-inflammatory cytokine, such as IL-10, reached significant level in insulin treated donors compared with those in controls. High dose insulin therapy decreases the concentrations of inflammatory cytokines in brain dead donors and preserves normoglycemia. High dose of insulin may have anti-inflammatory effects in brain dead organ donors and therefore, improve the quality of donor organs and potentially improve outcomes. © Georg Thieme Verlag KG Stuttgart · New York.

[THE EFFECT OF 5 DAYS IMMERSION IN DEAD SEA WATER ON BLOOD GLUCOSE LEVELS IN TYPE 2 DIABETES MELLITUS PATIENTS].

PubMed

Brzezinski Sinai, Isaac; Lior, Yotam; Brzezinski Sinai, Noa; Harari, Marco; Liberty, Idit F

2016-02-01

Body immersion in plain water or mineral water induces significant and unique physiological changes in most body systems. In a previous pilot study, a significant reduction in blood glucose levels among diabetes mellitus (DM) patients was found following a single immersion in Dead Sea water but not after immersion in plain water. To study the immediate and long term effects of immersion in mineral water for five consecutive days on blood glucose in patients with type 2 DM. A total of 34 patients with type 2 DM were divided into 2 groups: The first immersed in a plain water pool and the second immersed in a Dead Sea water pool; both pools were warmed to a temperature of 35°C. Immersions for 20 minutes occurred twice daily: two hours after breakfast and before dinner. Seven samples of capillary blood glucose levels were taken: fasting, before and after every immersion, prior to lunch and before bedtime. Hemoglobin A1C (HbA1c) was taken prior to the study and a re-check was conducted during the 12 weeks following the study. Blood glucose levels significantly decreased immediately after immersion both in Dead Sea water and plain water compared to their values prior to immersion (p<0.001). No significant difference was noted between both types of water. A decrease in fasting glucose levels was observed only in the group immersed in Dead Sea water when compared to plain water (6.83±5.68 mg/dl versus 4.37±1.79 respectively and the difference was close to statistical significance (p=0.071. There were no changes in HbA1c levels. Immersion for 20 minutes in water (Dead Sea or plain water) at a temperature of 35°C induced an immediate reduction in glucose levels in patients with type 2 DM.

The effects of α-cellulose extraction and blue-stain fungus on retrospective studies of carbon and oxygen isotope variation in live and dead trees†

USGS Publications Warehouse

English, N.B.; McDowell, N.G.; Allen, Craig D.; Mora, C.

2011-01-01

Tree-ring carbon and oxygen isotope ratios from live and recently dead trees may reveal important mechanisms of tree mortality. However, wood decay in dead trees may alter the δ13C and δ18O values of whole wood obscuring the isotopic signal associated with factors leading up to and including physiological death. We examined whole sapwood and α-cellulose from live and dead specimens of ponderosa pine (Pinus ponderosa), one-seed juniper (Juniperous monosperma), piñon pine (Pinus edulis) and white fir (Abies concolor), including those with fungal growth and beetle frass in the wood, to determine if α-cellulose extraction is necessary for the accurate interpretation of isotopic compositions in the dead trees. We found that the offset between the δ13C or δ18O values of α-cellulose and whole wood was the same for both live and dead trees across a large range of inter-annual and regional climate differences. The method of α-cellulose extraction, whether Leavitt-Danzer or Standard Brendel modified for small samples, imparts significant differences in the δ13C (up to 0.4‰) and δ18O (up to 1.2‰) of α-cellulose, as reported by other studies. There was no effect of beetle frass or blue-stain fungus (Ophiostoma) on the δ13C and δ18O of whole wood or α-cellulose. The relationships between whole wood and α-cellulose δ13C for ponderosa, piñon and juniper yielded slopes of ~1, while the relationship between δ18O of whole wood and α-cellulose was less clear. We conclude that there are few analytical or sampling obstacles to retrospective studies of isotopic patterns of tree mortality in forests of the western United States.

The effects of α-cellulose extraction and blue-stain fungus on retrospective studies of carbon and oxygen isotope variation in live and dead trees.

PubMed

English, Nathan B; McDowell, Nate G; Allen, Craig D; Mora, Claudia

2011-10-30

Tree-ring carbon and oxygen isotope ratios from live and recently dead trees may reveal important mechanisms of tree mortality. However, wood decay in dead trees may alter the δ(13)C and δ(18)O values of whole wood obscuring the isotopic signal associated with factors leading up to and including physiological death. We examined whole sapwood and α-cellulose from live and dead specimens of ponderosa pine (Pinus ponderosa), one-seed juniper (Juniperous monosperma), piñon pine (Pinus edulis) and white fir (Abies concolor), including those with fungal growth and beetle frass in the wood, to determine if α-cellulose extraction is necessary for the accurate interpretation of isotopic compositions in the dead trees. We found that the offset between the δ(13)C or δ(18)O values of α-cellulose and whole wood was the same for both live and dead trees across a large range of inter-annual and regional climate differences. The method of α-cellulose extraction, whether Leavitt-Danzer or Standard Brendel modified for small samples, imparts significant differences in the δ(13)C (up to 0.4‰) and δ(18) O (up to 1.2‰) of α-cellulose, as reported by other studies. There was no effect of beetle frass or blue-stain fungus (Ophiostoma) on the δ(13)C and δ(18)O of whole wood or α-cellulose. The relationships between whole wood and α-cellulose δ(13)C for ponderosa, piñon and juniper yielded slopes of ~1, while the relationship between δ(18)O of whole wood and α-cellulose was less clear. We conclude that there are few analytical or sampling obstacles to retrospective studies of isotopic patterns of tree mortality in forests of the western United States. Published in 2011 by John Wiley & Sons, Ltd.

Transducer Workshop (17th) Held in San Diego, California on June 22-24, 1993

DTIC Science & Technology

1993-06-01

weight in a drop tower, such as the primer tester shown in figure 1. The calibration procedure must be repeated for each lot of copper inserts, and small...force vs. time curve (i.e impulse = area unxer the curve). The FPyF can be used in the primer tester (shown in figure 1) as well as in a weapon...microphones. Plstonphone Output 124 dB, 250 Hz DEAD WEIGHT TESTIER USED AS A PRESSURE RELEASE CALIBRATOR The dead weight tester is designed and most

Organochlorine residues and reproduction in the big brown bat

USGS Publications Warehouse

Clark, D.R.; Lamont, T.G.

1976-01-01

Twenty-six pregnant big brown bats (Eptesicus fuscus) were collected at Montpelier Barn, Laurel, Maryland, and kept in individual cages until parturition. Seven young in 5 litters were born dead; 21 litters contained only living young. Polychlorinated bipbenyl (PCB, Aroclor 1260) crossed the placenta two to three times more readily than did DDE. Concentrations of PCB were significantly greater in litters with dead young than in litters where both young were born alive. The concentration of PCB in adult females plus their litters declined with increasing age of the female.

Jack Rabbit Pretest 2021E PT6 Photonic Doppler Velocimetry Data Volume 6 Section 1

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

Hart, M M; Strand, O T; Bosson, S T

The Jack Rabbit Pretest (PT) 2021E PT6 experiment was fired on April 1, 2008 at the Contained Firing Facility, Site 300, Lawrence Livermore National Laboratory. This experiment is part of an effort to determine the properties of LX-17 in a regime where corner-turning behavior and dead-zone formation are not well understood. Photonic Doppler Velocimetry (PDV) measured diagnostic plate velocities confirming the presence of a persistent LX-17 dead-zone formation and the resultant impulse gradient applied under the diagnostic plate. The Jack Rabbit Pretest 2021E PT6, 160 millimeter diameter experiment returned data on all eight PDV probes. The probes measured on themore » central axis and at 20, 30, 35, 45, 55, 65, 75 millimeters from the central axis. The experiment was shot at an ambient room temperature of 65 degrees Fahrenheit. The earliest PDV signal extinction was 54.2 microseconds at 30 millimeters. The latest PDV signal extinction time was 64.5 microseconds at the central axis. The measured velocity ranged from meters per second to thousands of meters per second. First detonation wave induced jump-off was measured at 55 millimeters at 14.1 microseconds. The PDV data provided an unambiguous indication of dead-zone formation and an impulse gradient applied to the diagnostic plate. The central axis had a last measured velocity of 1860 meters per second. At 55 millimeters the last measured velocity was 2408 meters per second. The low-to-high velocity ratio was 0.77. Velocity data was integrated to compute diagnostic plate cross section profiles. Velocity data was differentiated to compute a peak pressure under the diagnostic plate at the central axis of 227 kilobars at 20.1 microseconds, indicating a late time chemical reaction in the LX-17 dead-zone. Substantial motion (>1 m/s) of the diagnostic plate over the dead-zone is followed by detonation region motion within approximately 1.7 microseconds.« less

The death assemblage as a marker for habitat and an indicator of climate change: Georges Bank, surfclams and ocean quahogs

NASA Astrophysics Data System (ADS)

Powell, Eric N.; Kuykendall, Kelsey M.; Moreno, Paula

2017-06-01

A comprehensive dataset for the Georges Bank region is used to directly compare the distribution of the death assemblage and the living community at large spatial scales and to assess the application of the death assemblage in tracking changes in species' distributional pattern as a consequence of climate change. Focus is placed on the biomass-dominant clam species of the northwest Atlantic continental shelf: the surfclam Spisula solidissima and the ocean quahog Arctica islandica, for which extensive datasets exist on the distributions of the living population and the death assemblage. For both surfclams and ocean quahogs, the distribution of dead shells, in the main, tracked the distribution of live animals relatively closely. Thus, for both species, the presence of dead shells was a positive indicator of present, recent, or past occupation by live animals. Shell dispersion within habitat was greater for surfclams than for ocean quahogs either due to spatial time averaging, animals not living in all habitable areas all of the time, or parautochthonous redistribution of shell. The regional distribution of dead shell differed from the distribution of live animals, for both species, in a systematic way indicative of range shifts due to climate change. In each case the differential distribution was consistent with warming of the northwest Atlantic. Present-day overlap of live surfclams with live ocean quahogs was consistent with the expectation that the surfclam's range is shifting into deeper water in response to the recent warming trend. The presence of locations devoid of dead shells where live surfclams nevertheless were collected measures the recentness of this event. The presence of dead ocean quahog shells at shallower depths than live ocean quahogs offers good evidence that a range shift has occurred in the past, but prior to the initiation of routine surveys in 1980. Possibly, this range shift tracks initial colonization at the end of the Little Ice Age.

Servo-controlled hind-limb electrical stimulation for short-term arterial pressure control.

PubMed

Kawada, Toru; Shimizu, Shuji; Yamamoto, Hiromi; Shishido, Toshiaki; Kamiya, Atsunori; Miyamoto, Tadayoshi; Sunagawa, Kenji; Sugimachi, Masaru

2009-05-01

Autonomic neural intervention is a promising tool for modulating the circulatory system thereby treating some cardiovascular diseases. In 8 pentobarbital-anesthetized cats, it was examined whether the arterial pressure (AP) could be controlled by acupuncture-like hind-limb electrical stimulation (HES). With a 0.5-ms pulse width, HES monotonically reduced AP as the stimulus current increased from 1 to 5 mA, suggesting that the stimulus current could be a primary control variable. In contrast, the depressor effect of HES showed a nadir approximately 10 Hz in the frequency range between 1 and 100 Hz. Dynamic characteristics of the AP response to HES approximated a second-order low-pass filter with dead time (gain: -10.2 +/- 1.6 mmHg/mA, natural frequency: 0.040 +/- 0.004 Hz, damping ratio 1.80 +/- 0.24, dead time: 1.38 +/- 0.13 s, mean +/- SE). Based on these dynamic characteristics, a servo-controlled HES system was developed. When a target AP value was set at 20 mmHg below the baseline AP, the time required for the AP response to reach 90% of the target level was 38 +/- 10 s. The steady-state error between the measured and target AP values was 1.3 +/- 0.1 mmHg. Autonomic neural intervention by acupuncture-like HES might provide an additional modality to quantitatively control the circulatory system.

Gram-Negative Bacterial Wound Infections

DTIC Science & Technology

2014-05-01

shows an effect with increasing concentration, however survival analysis does not show a significant difference between treatment groups and controls ...with 3 dead larvae in the 25 mM group compared to a single dead larva in the control group (Fig. 7). Probit analysis estimates the lethal...statistically differ- ent from that of the control group . The levels (CFU/g) of bacteria in lung tissue correlated with the survival curves. The median

Numerical simulation of dielectrophoretic separation of live/dead cells using a three-dimensional nonuniform AC electric field in micro-fabricated devices.

PubMed

Tada, Shigeru

2015-01-01

The analysis of cell separation has many important biological and medical applications. Dielectrophoresis (DEP) is one of the most effective and widely used techniques for separating and identifying biological species. In the present study, a DEP flow channel, a device that exploits the differences in the dielectric properties of cells in cell separation, was numerically simulated and its cell-separation performance examined. The samples of cells used in the simulation were modeled as human leukocyte (B cell) live and dead cells. The cell-separation analysis was carried out for a flow channel equipped with a planar electrode on the channel's top face and a pair of interdigitated counter electrodes on the bottom. This yielded a three-dimensional (3D) nonuniform AC electric field in the entire space of the flow channel. To investigate the optimal separation conditions for mixtures of live and dead cells, the strength of the applied electric field was varied. With appropriately selected conditions, the device was predicted to be very effective at separating dead cells from live cells. The major advantage of the proposed method is that a large volume of sample can be processed rapidly because of a large spacing of the channel height.

Individual traits as determinants of time to death under extreme drought in Pinus sylvestris L.

PubMed

Garcia-Forner, Núria; Sala, Anna; Biel, Carme; Savé, Robert; Martínez-Vilalta, Jordi

2016-10-01

Plants exhibit a variety of drought responses involving multiple interacting traits and processes, which makes predictions of drought survival challenging. Careful evaluation of responses within species, where individuals share broadly similar drought resistance strategies, can provide insight into the relative importance of different traits and processes. We subjected Pinus sylvestris L. saplings to extreme drought (no watering) leading to death in a greenhouse to (i) determine the relative effect of predisposing factors and responses to drought on survival time, (ii) identify and rank the importance of key predictors of time to death and (iii) compare individual characteristics of dead and surviving trees sampled concurrently. Time until death varied over 3 months among individual trees (from 29 to 147 days). Survival time was best predicted (higher explained variance and impact on the median survival time) by variables related to carbon uptake and carbon/water economy before and during drought. Trees with higher concentrations of monosaccharides before the beginning of the drought treatment and with higher assimilation rates prior to and during the treatment survived longer (median survival time increased 25-70 days), even at the expense of higher water loss. Dead trees exhibited less than half the amount of nonstructural carbohydrates (NSCs) in branches, stem and relative to surviving trees sampled concurrently. Overall, our results indicate that the maintenance of carbon assimilation to prevent acute depletion of NSC content above some critical level appears to be the main factor explaining survival time of P. sylvestris trees under extreme drought. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Detector Development for the abBA Experiment.

PubMed

Seo, P-N; Bowman, J D; Mitchell, G S; Penttila, S I; Wilburn, W S

2005-01-01

We have developed a new type of field-expansion spectrometer to measure the neutron beta decay correlations (a, b, B, and A). A precision measurement of these correlations places stringent requirements on charged particle detectors. The design employs large area segmented silicon detectors to detect both protons and electrons in coincidence. Other requirements include good energy resolution (< 5 keV), a thin dead layer to allow observation of 30-keV protons, fast timing resolution (~1 ns) to reconstruct electron-backscattering events, and nearly unity efficiency. We report results of testing commercially available surface-barrier silicon detectors for energy resolution and timing performance, and measurement of the dead-layer thickness of ion-implanted silicon detectors with a 3.2 MeV alpha source.

Proceedings of the symposium on the ecology and management of dead wood in western forests

Treesearch

William F. Laudenslayer; Patrick J. Shea; Bradley E. Valentine; C. Phillip Weatherspoon; Thomas E. Lisle

2002-01-01

Dead trees, both snags (standing dead trees) and logs (downed dead trees), are critical elements of healthy and productive forests. The “Symposium on the Ecology and Management of Dead Wood in Western Forests” was convened to bring together forest researchers and managers to share the current state of knowledge relative to the values and interactions of dead wood to...

Adaptive engine injection for emissions reduction

DOEpatents

Reitz, Rolf D. : Sun, Yong

2008-12-16

NOx and soot emissions from internal combustion engines, and in particular compression ignition (diesel) engines, are reduced by varying fuel injection timing, fuel injection pressure, and injected fuel volume between low and greater engine loads. At low loads, fuel is injected during one or more low-pressure injections occurring at low injection pressures between the start of the intake stroke and approximately 40 degrees before top dead center during the compression stroke. At higher loads, similar injections are used early in each combustion cycle, in addition to later injections which preferably occur between about 90 degrees before top dead center during the compression stroke, and about 90 degrees after top dead center during the expansion stroke (and which most preferably begin at or closely adjacent the end of the compression stroke). These later injections have higher injection pressure, and also lower injected fuel volume, than the earlier injections.

Optimization of a Viability PCR Method for the Detection of Listeria monocytogenes in Food Samples.

PubMed

Agustí, Gemma; Fittipaldi, Mariana; Codony, Francesc

2018-06-01

Rapid detection of Listeria and other microbial pathogens in food is an essential part of quality control and it is critical for ensuring the safety of consumers. Culture-based methods for detecting foodborne pathogens are time-consuming, laborious and cannot detect viable but non-culturable microorganism, whereas viability PCR methodology provides quick results; it is able to detect viable but non-culturable cells, and allows for easier handling of large amount of samples. Although the most critical point to use viability PCR technique is achieving the complete exclusion of dead cell amplification signals, many improvements are being introduced to overcome this. In the present work, the yield of dead cell DNA neutralization was enhanced by incorporating two new sample treatment strategies: tube change combined with a double light treatment. This procedure was successfully tested using artificially contaminated food samples, showing improved neutralization of dead cell DNA.

All Eyes on Egypt: Islam and the Medical Use of Dead Bodies Amidst Cairo's Political Unrest.

PubMed

Hamdy, Sherine

2016-01-01

Using dead bodies for medical purposes has long been considered taboo in Egypt. Public health campaigns, physicians' pleas, and the urgings of religious scholars all failed to alter public opinion regarding the donation of dead bodies either for instructional material or for therapeutic treatments. Yet in 2011, amid revolutionary turmoil in Egypt, a campaign was launched for people to donate their eyes upon death; this time, people readily signed up to be donors. Focusing on mass eye trauma that occurred in Egypt amid the political uprisings of 2011, I raise questions about when and why Islam can explain people's attitudes and behaviors, particularly toward death and medicine. The case of mass eye trauma in Egypt and citizens' reformulations of questions once jealously controlled by state-aligned doctors, politicians, and religious scholars unsettles the boundaries between 'religion' and 'secularism' in medical practice. [Formula: see text].

An investigation into the factors effective in the consent of families with brain-dead patients candidates for organ donation in Isfahan, Iran in 2012-13

PubMed Central

Khajooei, Maryam Khalifehsoltani; Zamani, Fereshteh; Mehr, Asieh Maghami

2016-01-01

Background: Studies have shown that, with regard to social, cultural, and institutional contexts, several factors affect family decision-making on organ donation. This study aimed to investigate the effective factors in organ donation by family members with brain-dead patients. Materials and Methods: This was a descriptive-comparative study in which a researcher-made questionnaire was used to collect data. The reliability of the questionnaire was obtained as 0.81 using Cronbach's alpha. The study sample consisted of 85 members of families with brain-dead patients in Isfahan, Iran in 2012–13. The collected data were analyzed using the Statistical Package for the Social Sciences version 20.0, and the level of significance was considered as <0.05. Results: The obtained results indicated that factors such as age, marital status, level of education, and cause of brain death did not have any effect on their families consent, whereas factors such as gender, duration of hospitalization, having an organ donation card, personal view of the brain-dead patient, and the number of patient's children had a significant relationship with the consent on organ donation. In addition, the care and treatment team were effective in family decisions regarding organ donation. Conclusions: In general, the necessary culture and increasing the population awareness and their knowledge can be a positive step in this regard and may bring about an easy and rapid acceptance of organ donation by the involved families. PMID:28194201

Dead Sea deep cores: A window into past climate and seismicity

NASA Astrophysics Data System (ADS)

Stein, Mordechai; Ben-Avraham, Zvi; Goldstein, Steven L.

2011-12-01

The area surrounding the Dead Sea was the locus of humankind's migration out of Africa and thus has been the home of peoples since the Stone Age. For this reason, understanding the climate and tectonic history of the region provides valuable insight into archaeology and studies of human history and helps to gain a better picture of future climate and tectonic scenarios. The deposits at the bottom of the Dead Sea are a geological archive of the environmental conditions (e.g., rains, floods, dust storms, droughts) during ice ages and warm ages, as well as of seismic activity in this key region. An International Continental Scientific Drilling Program (ICDP) deep drilling project was performed in the Dead Sea between November 2010 and March 2011. The project was funded by the ICDP and agencies in Israel, Germany, Japan, Norway, Switzerland, and the United States. Drilling was conducted using the new Large Lake Drilling Facility (Figure 1), a barge with a drilling rig run by DOSECC, Inc. (Drilling, Observation and Sampling of the Earth's Continental Crust), a nonprofit corporation dedicated to advancing scientific drilling worldwide. The main purpose of the project was to recover a long, continuous core to provide a high resolution record of the paleoclimate, paleoenvironment, paleoseismicity, and paleomagnetism of the Dead Sea Basin. With this, scientists are beginning to piece together a record of the climate and seismic history of the Middle East during the past several hundred thousand years in millennial to decadal to annual time resolution.

[Cutaneous melanoma - "black death" of modern times? Traces in contemporary literature].

PubMed

Bahmer, F A; Bahmer, J A

2013-11-01

Cutaneous melanoma, sometimes labeled as "black skin cancer", is increasing in frequency and becoming a more common literary motive. In US literature, Sylvia Plath and Charles Bukowski depicted melanoma more than 50 years ago, later Stephen King and Thomas C. Boyle. In German literature, Charlotte Roche shortly mentioned this tumor. Jörg Pönnighaus, both poet and dermatologist, intensively deals in his poems with the effects melanoma has on patients and doctors alike. Melanoma definitely is not the "Black Death" of modern times. However, the perception of this tumor as extremely malignant and as life-threatening makes melanoma a metaphor of the deadly danger of cancer.

Negative and positive interactions among plants: effects of competitors and litter on seedling emergence and growth of forest and grassland species.

PubMed

Loydi, A; Donath, T W; Otte, A; Eckstein, R L

2015-05-01

Living plant neighbours, but also their dead aboveground remains (i.e. litter), may individually exert negative or positive effects on plant recruitment. Although living plants and litter co-occur in most ecosystems, few studies have addressed their combined effects, and conclusions are ambivalent. Therefore, we examined the response in terms of seedling emergence and growth of herbaceous grassland and forest species to different litter types and amounts and the presence of competitors. We conducted a pot experiment testing the effects of litter type (grass, oak), litter amount (low, medium, high) and interspecific competition (presence or absence of four Festuca arundinacea individuals) on seedling emergence and biomass of four congeneric pairs of hemicryptophytes from two habitat types (woodland, grassland). Interactions between litter and competition were weak. Litter presence increased competitor biomass. It also had positive effects on seedling emergence at low litter amounts and negative effects at high litter amounts, while competition had no effect on seedling emergence. Seedling biomass was negatively affected by the presence of competitors, and this effect was stronger in combination with high amounts of litter. Litter affected seedling emergence while competition determined the biomass of the emerged individuals, both affecting early stages of seedling recruitment. High litter accumulation also reduced seedling biomass, but this effect seemed to be additive to competitor effects. This suggests that live and dead plant mass can affect species recruitment in natural systems, but the mechanisms by which they operate and their timing differ. © 2014 German Botanical Society and The Royal Botanical Society of the Netherlands.

46 CFR 171.117 - Dead covers.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 7 2011-10-01 2011-10-01 false Dead covers. 171.117 Section 171.117 Shipping COAST... Dead covers. (a) Except as provided in paragraph (b) of this section, each port light with the sill located below the margin line must have a hinged, inside dead cover. (b) The dead cover on a port light...

46 CFR 171.117 - Dead covers.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 7 2014-10-01 2014-10-01 false Dead covers. 171.117 Section 171.117 Shipping COAST... Dead covers. (a) Except as provided in paragraph (b) of this section, each port light with the sill located below the margin line must have a hinged, inside dead cover. (b) The dead cover on a port light...

46 CFR 171.117 - Dead covers.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 7 2013-10-01 2013-10-01 false Dead covers. 171.117 Section 171.117 Shipping COAST... Dead covers. (a) Except as provided in paragraph (b) of this section, each port light with the sill located below the margin line must have a hinged, inside dead cover. (b) The dead cover on a port light...

46 CFR 171.117 - Dead covers.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 7 2012-10-01 2012-10-01 false Dead covers. 171.117 Section 171.117 Shipping COAST... Dead covers. (a) Except as provided in paragraph (b) of this section, each port light with the sill located below the margin line must have a hinged, inside dead cover. (b) The dead cover on a port light...

46 CFR 171.117 - Dead covers.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 7 2010-10-01 2010-10-01 false Dead covers. 171.117 Section 171.117 Shipping COAST... Dead covers. (a) Except as provided in paragraph (b) of this section, each port light with the sill located below the margin line must have a hinged, inside dead cover. (b) The dead cover on a port light...

Evaluation of Split Version and Feedback Module on the Improvement of Time Trade-Off Data.

PubMed

Wong, Eliza L Y; Shah, Koonal; Cheung, Annie W L; Wong, Amy Y K; Visser, Martijn; Stolk, Elly

2018-06-01

EQ-5D-5L valuation studies previously reported many inconsistent responses in time trade-off (TTO) data. A number of possible elements, including ordering effects of the valuation tasks, mistakes at the sorting question, and interviewers' (learning) effects, may contribute to their inconsistency. This study aimed to evaluate the effect of two modifications on consistency of TTO data in The Netherlands (NL) and Hong Kong (HK): (1) separating the valuation of the Better than Dead (BTD) and Worse than Dead (WTD) states; and (2) Implementation of feedback (FB) module by offering an opportunity to review TTO responses. A crossover design with two study arms was used to test the effect of the modifications. In each jurisdiction, six interviewers were involved where half the interviewers started using the standard version, and the other half started with the split version. Each version was switched after every 25 (NL) or 30 (HK) interviews until 400 interviews were completed. In the NL and HK, 404 and 403 respondents participated, respectively. With the use of the FB module, the proportion of respondents with inconsistent responses was lowered from 17.8% to 10.6% (P < 0.001) in NL and from 31.8% to 22.3% (P = 0.003) in HK. The result of separating the valuation of BTD and WTD states was not straightforward because it reduced the inconsistency rate in NL but not in HK. The results support implementation of the FB module to promote the consistency of the data. The separation of the BTD and WTD task is not supported. Copyright © 2018 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

Protective effect of selenium on lung cancer in smelter workers.

PubMed Central

Gerhardsson, L; Brune, D; Nordberg, I G; Wester, P O

1985-01-01

A possible protective effect of selenium against lung cancer has been indicated in recent studies. Workers in copper smelters are exposed to a combination of airborne selenium and carcinogens. In this study lung tissue concentrations of selenium, antimony, arsenic, cadmium, chromium, cobalt, lanthanum, and lead from 76 dead copper smelter workers were compared with those of 15 controls from a rural area and 10 controls from an urban area. The mean exposure time for the dead workers was 31.2 years, and the mean retirement time after the end of exposure 7.2 years. Lung cancer appeared in the workers with the lowest selenium lung tissue levels (selenium median value 71 micrograms/kg wet weight), as compared with both the controls (rural group, median value 110; urban group, median value 136) and other causes of death among the workers (median value 158). The quotient between the metals and selenium was used for comparison: a high quotient indicating a low protective effect of selenium and vice versa. The median values of the quotients between antimony, arsenic, cadmium, lanthanum, lead, chromium, and cobalt versus selenium were all numerically higher among the cases of lung cancer, the first five significantly higher (p less than 0.05) in 28 of the 35 comparisons between the lung cancer group and all other groups of smelter workers and controls. The different lung metal concentrations for each person were weighted according to their carcinogenic potency (Crx4 + Asx3 + Cdx2 + Sbx1 + Cox1 + Lax1 + Pbx1) against their corresponding selenium concentrations. From these calculations the protective effect of selenium was even more pronounced. PMID:4041390

Whose body is it anyway?: trading the dead poor, coroner's disputes, and the business of anatomy at Oxford University, 1885-1929.

PubMed

Hurren, Elizabeth T

2008-01-01

This article examines the application of the Anatomy Act (1832) at Oxford University, circa 1885-1929. For the first time it retraces the economy of supply in dead bodies, sold by various black-market intermediaries and welfare agencies, transported on the railway to Oxford. Both pauper cadavers and body parts were used to train doctors in human anatomy at a time when student demand always exceeded the economy of supply. An added problem was that the trade in dead bodies was disrupted by a city coroner for Oxford in a bid to improve his professional standing. Disputes about medico-legal authority over the pauper corpse meant that the Anatomy Department failed to convince the local poor in the city center to sell their loved ones' remains for dissection on a regular basis. Adverse publicity was a constant financial headache for anatomists. Consistently, they had to pay higher prices for cadavers than their competitors did. Often bodies were purchased in surrounding Midlands towns. This context explains why the Anatomy Department at Oxford failed at the business of anatomy in the late Victorian and early Edwardian eras.

PMA-PhyloChip DNA Microarray to Elucidate Viable Microbial Community Structure

NASA Technical Reports Server (NTRS)

Venkateswaran, Kasthuri J.; Stam, Christina N.; Andersen, Gary L.; DeSantis, Todd

2011-01-01

Since the Viking missions in the mid-1970s, traditional culture-based methods have been used for microbial enumeration by various NASA programs. Viable microbes are of particular concern for spacecraft cleanliness, for forward contamination of extraterrestrial bodies (proliferation of microbes), and for crew health/safety (viable pathogenic microbes). However, a "true" estimation of viable microbial population and differentiation from their dead cells using the most sensitive molecular methods is a challenge, because of the stability of DNA from dead cells. The goal of this research is to evaluate a rapid and sensitive microbial detection concept that will selectively estimate viable microbes. Nucleic acid amplification approaches such as the polymerase chain reaction (PCR) have shown promise for reducing time to detection for a wide range of applications. The proposed method is based on the use of a fluorescent DNA intercalating agent, propidium monoazide (PMA), which can only penetrate the membrane of dead cells. The PMA-quenched reaction mixtures can be screened, where only the DNA from live cells will be available for subsequent PCR reaction and microarray detection, and be identified as part of the viable microbial community. An additional advantage of the proposed rapid method is that it will detect viable microbes and differentiate from dead cells in only a few hours, as opposed to less comprehensive culture-based assays, which take days to complete. This novel combination approach is called the PMA-Microarray method. DNA intercalating agents such as PMA have previously been used to selectively distinguish between viable and dead bacterial cells. Once in the cell, the dye intercalates with the DNA and, upon photolysis under visible light, produces stable DNA adducts. DNA cross-linked in this way is unavailable for PCR. Environmental samples suspected of containing a mixture of live and dead microbial cells/spores will be treated with PMA, and then incubated in the dark. Thereafter, the sample is exposed to visible light for five minutes, so that the DNA from dead cells will be cross-linked. Following this PMA treatment step, the sample is concentrated by centrifugation and washed (to remove excessive PMA) before DNA is extracted. The 16S rRNA gene fragments will be amplified by PCR to screen the total microbial community using PhyloChip DNA microarray analysis. This approach will detect only the viable microbial community since the PMA intercalated DNA from dead cells would be unavailable for PCR amplification. The total detection time including PCR reaction for low biomass samples will be a few hours. Numerous markets may use this technology. The food industry uses spore detection to validate new alternative food processing technologies, sterility, and quality. Pharmaceutical and medical equipment companies also detect spores as a marker for sterility. This system can be used for validating sterilization processes, water treatment systems, and in various public health and homeland security applications.

Entropy is more resistant to artifacts than bispectral index in brain-dead organ donors.

PubMed

Wennervirta, Johanna; Salmi, Tapani; Hynynen, Markku; Yli-Hankala, Arvi; Koivusalo, Anna-Maria; Van Gils, Mark; Pöyhiä, Reino; Vakkuri, Anne

2007-01-01

To evaluate the usefulness of entropy and the bispectral index (BIS) in brain-dead subjects. A prospective, open, nonselective, observational study in the university hospital. 16 brain-dead organ donors. Time-domain electroencephalography (EEG), spectral entropy of the EEG, and BIS were recorded during solid organ harvest. State entropy differed significantly from 0 (isoelectric EEG) 28%, response entropy 29%, and BIS 68% of the total recorded time. The median values during the operation were state entropy 0.0, response entropy 0.0, and BIS 3.0. In four of 16 organ donors studied the EEG was not isoelectric, and nonreactive rhythmic activity was noted in time-domain EEG. After excluding the results from subjects with persistent residual EEG activity state entropy, response entropy, and BIS values differed from zero 17%, 18%, and 62% of the recorded time, respectively. Median values were 0.0, 0.0, and 2.0 for state entropy, response entropy, and BIS, respectively. The highest index values in entropy and BIS monitoring were recorded without neuromuscular blockade. The main sources of artifacts were electrocauterization, 50-Hz artifact, handling of the donor, ballistocardiography, electromyography, and electrocardiography. Both entropy and BIS showed nonzero values due to artifacts after brain death diagnosis. BIS was more liable to artifacts than entropy. Neither of these indices are diagnostic tools, and care should be taken when interpreting EEG and EEG-derived indices in the evaluation of brain death.

Wound healing activity of Persea americana (avocado) fruit: a preclinical study on rats.

PubMed

Nayak, B S; Raju, S S; Chalapathi Rao, A V

2008-03-01

Avocado (Persea americana) oil is rich in nutrient waxes, proteins and minerals, as well as vitamins A, D and E. It is an excellent source of enrichment for dry, damaged or chapped skin. This study aimed to evaluate the wound-healing activity of fruit extract of Persea americana in rats. The effect of topical and oral administration of Persea americana fruit extract (300 mg/kg/day) on excision and dead space wound models was evaluated. The rats used in the excision wound model were divided into four groups of five each and received either topical or oral treatment. The rats used in the dead space wound model were divided into two groups of five each and were treated orally. Healing was assessed by the rate of wound contraction, period of epithelialisation, granulation tissue weight and hydoxyproline content. In the excision wound model, complete healing (full epithelialisation) was observed on average on day 14 in the rats who receive oral or topical treatment. In contrast, the controls took approximately 17 days to heal completely. The extract-treated wounds were found to epithelialise faster than the controls (p < 0.001). Wet and dry granulation tissue weight and the hydroxyproline content of the tissue obtained from extract-treated animals used in the dead space wound model were significantly higher (p < 0.05) compared with the controls. Rate of wound contraction, epithelialisation time together with the hydroxyproline content and histological observations support the use of Persea americana in the management of wound healing.

Can homemade alcohol (Raksi) be useful for preserving dead bodies? An experiment on wistar albino rats.

PubMed

Dhungel, S; Maskey, D; Jha, C B; Bhattacharya, S; Paudel, B H; Shrestha, R N

2007-01-01

Embalming is the through disinfection and art of preserving bodies after death using chemical substances. It keeps a body life like in appearance during the time it lies in a state prior to funeral. This study was undertaken to investigate the effectiveness of Raksi in sacrificed rats in arresting postmortem changes and establishing scientific fact whether Raksi can be an alternative to standard embalming constituent if it is not available. 50 albino rats were systematically randomized into control and experiment groups. Raksi and distilled water were injected for embalming purpose intraventricularly in experiment and control groups of rats respectively and kept for 48 to 96 hours for observation for postmortem changes. Observations made at 48 and 72 hours of embalming revealed that Raksi can arrest postmortem changes in the rats up to 72 hours (3rd day) successfully in the experimental group whereas moderate to severe postmortem changes were seen in the control group. The experimental group showed mild degree of putrefactive changes, liberation of gases and liquefaction of tissues only at 96 hours (4th day) of embalming. The Raksi used in this experiment contained 34% of alcohol, which was determined by an alcohol hydrometer. Experiment clearly demonstrated from its result that raksi can be utilised temporarily for embalming since it contains alcohol and has preservative, bactericidal and disinfectant properties. It is concluded from the study that this knowledge if applied to dead human subjects, may preserve dead bodies temporarily allowing delayed funeral.

Patterns of mortality in a montane mixed-conifer forest in San Diego County, California.

PubMed

Freeman, Mary Pyott; Stow, Douglas A; An, Li

2017-10-01

We examine spatial patterns of conifer tree mortality and their changes over time for the montane mixed-conifer forests of San Diego County. These forest areas have recently experienced extensive tree mortality due to multiple factors. A spatial contextual image processing approach was utilized with high spatial resolution digital airborne imagery to map dead trees for the years 1997, 2000, 2002, and 2005 for three study areas: Palomar, Volcan, and Laguna mountains. Plot-based fieldwork was conducted to further assess mortality patterns. Mean mortality remained static from 1997 to 2002 (4, 2.2, and 4.2 trees/ha for Palomar, Volcan, and Laguna) and then increased by 2005 to 10.3, 9.7, and 5.2 trees/ha, respectively. The increase in mortality between 2002 and 2005 represents the temporal pattern of a discrete disturbance event, attributable to the 2002-2003 drought. Dead trees are significantly clustered for all dates, based on spatial cluster analysis, indicating that they form distinct groups, as opposed to spatially random single dead trees. Other tests indicate no directional shift or spread of mortality over time, but rather an increase in density. While general temporal and spatial mortality processes are uniform across all study areas, the plot-based species and quantity distribution of mortality, and diameter distributions of dead vs. living trees, vary by study area. The results of this study improve our understanding of stand- to landscape-level forest structure and dynamics, particularly by examining them from the multiple perspectives of field and remotely sensed data. © 2017 by the Ecological Society of America.

The "New Deadly Quartet" for cardiovascular disease in the 21st century: obesity, metabolic syndrome, inflammation and climate change: how does statin therapy fit into this equation?

PubMed

Clearfield, Michael; Pearce, Melissa; Nibbe, Yasmin; Crotty, David; Wagner, Alesia

2014-01-01

Despite population-based improvements in cardiovascular risk factors, such as blood pressure, cholesterol and smoking, cardiovascular disease still remains the number-one cause of mortality in the United States. In 1989, Kaplan coined the term "Deadly Quartet" to represent a combination of risk factors that included upper body obesity, glucose intolerance, hypertriglyceridemia and hypertension [Kaplan in Arch Int Med 7:1514-1520, 1989]. In 2002, the third report of the National Cholesterol Education Program Adult Treatment Panel (NCEP-ATP III) essentially added low HDL-C criteria and renamed this the "metabolic syndrome." [The National Cholesterol Education Program (NCEP) in JAMA 285:2486-2497, 2001] However, often forgotten was that a pro-inflammatory state and pro-thrombotic state were also considered components of the syndrome, albeit the panel did not find enough evidence at the time to recommend routine screening for these risk factors [The National Cholesterol Education Program (NCEP) in JAMA 285:2486-2497, 2001]. Now over a decade later, it may be time to reconsider this deadly quartet by reevaluating the roles of obesity and subclinical inflammation as they relate to the metabolic syndrome. To complete this new quartet, the addition of increased exposure to elevated levels of particulate matter in the atmosphere may help elucidate why this cardiovascular pandemic continues, despite our concerted efforts. In this article, we will summarize the evidence, focusing on how statin therapy may further impact this new version of the "deadly quartet".

Pulpability of beetle-killed spruce. Forest Service research paper

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

Scott, G.M.; Bormett, D.W.; Sutherland, N.R.

1996-08-01

Infestation of the Dendroctonus rufipennis beetle has resulted in large stands of dead and dying timber on the Kenai Peninsula in Alaska. Tests were conducted to evaluate the value of beetle-killed spruce as pulpwood. The results showed that live and dead spruce wood can be pulped effectively. The two least deteriorated classes and the most deteriorated class of logs had similar characteristics when pulped; the remaining class had somewhat poorer pulpability.

45 CFR 46.206 - Research involving, after delivery, the placenta, the dead fetus or fetal material.

Code of Federal Regulations, 2012 CFR

2012-10-01

..., the dead fetus or fetal material. 46.206 Section 46.206 Public Welfare DEPARTMENT OF HEALTH AND HUMAN... placenta, the dead fetus or fetal material. (a) Research involving, after delivery, the placenta; the dead fetus; macerated fetal material; or cells, tissue, or organs excised from a dead fetus, shall be...

45 CFR 46.206 - Research involving, after delivery, the placenta, the dead fetus or fetal material.

Code of Federal Regulations, 2010 CFR

2010-10-01

..., the dead fetus or fetal material. 46.206 Section 46.206 Public Welfare DEPARTMENT OF HEALTH AND HUMAN... placenta, the dead fetus or fetal material. (a) Research involving, after delivery, the placenta; the dead fetus; macerated fetal material; or cells, tissue, or organs excised from a dead fetus, shall be...

45 CFR 46.206 - Research involving, after delivery, the placenta, the dead fetus or fetal material.

Code of Federal Regulations, 2013 CFR

2013-10-01

..., the dead fetus or fetal material. 46.206 Section 46.206 Public Welfare DEPARTMENT OF HEALTH AND HUMAN... placenta, the dead fetus or fetal material. (a) Research involving, after delivery, the placenta; the dead fetus; macerated fetal material; or cells, tissue, or organs excised from a dead fetus, shall be...

45 CFR 46.206 - Research involving, after delivery, the placenta, the dead fetus or fetal material.

Code of Federal Regulations, 2014 CFR

2014-10-01

..., the dead fetus or fetal material. 46.206 Section 46.206 Public Welfare Department of Health and Human... placenta, the dead fetus or fetal material. (a) Research involving, after delivery, the placenta; the dead fetus; macerated fetal material; or cells, tissue, or organs excised from a dead fetus, shall be...

45 CFR 46.206 - Research involving, after delivery, the placenta, the dead fetus or fetal material.

Code of Federal Regulations, 2011 CFR

2011-10-01

..., the dead fetus or fetal material. 46.206 Section 46.206 Public Welfare DEPARTMENT OF HEALTH AND HUMAN... placenta, the dead fetus or fetal material. (a) Research involving, after delivery, the placenta; the dead fetus; macerated fetal material; or cells, tissue, or organs excised from a dead fetus, shall be...

[Cardiopulmonary resuscitation already in Egypt 5,000 years ago?].

PubMed

Ocklitz, A

1997-06-06

In light of the medically relevant features of the ancient Egyptian mouth-opening ceremony, the question of the effectiveness of medical practices in Egypt thousands of years ago is examined, whereby the religious and cultural framework also plays a significant role. In the Land on the Nile myth and reality clearly generated special conditions which favoured the systematic treatment of questions of resuscitation. Numerous examples show that this had practical consequences in the area of everyday medicine. In addition, rebirth and resurrection were central elements of the cult of the dead which had exact medical equivalents. These equivalents may demonstrate the advanced state of resuscitation practices in Egypt at that time. In this context, a reconstruction of an ancient Egyptian mouth-opening instrument is presented. In the cult of the dead, this instrument played a role which can be compared to the function of a modern laryngoscope. It appears possible that at the time of the pyramids the Egyptians already had an understanding of the technology required to perform instrument-aided artificial respiration. Whether or not they actually possessed a fundamental knowledge of the principles of cardio-pulmonary resuscitation remains unclear. Nevertheless, the astonishingly functional characteristics of the reconstructed mouth-opening instrument suggest that it was developed for more than purely symbolic purposes.

Assessment of three dead detector correction methods for cone-beam computed tomography

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

Nelms, David W.; Shukla, Hemant I.; Nixon, Earl

Purpose: Dead detectors due to manufacturing defects or radiation damage in the electronic portal imaging devices (EPIDs) used for cone-beam computed tomography (CBCT) can lead to image degradation and ring artifacts. In this work three dead detector correction methods were assessed using megavoltage CBCT (MVCBCT) as a test system, with the goals of assessing the relative effectiveness of the three methods and establishing the conditions for which they fail. Methods: MVCBCT projections acquired with four linacs at 8 and 60 MU (monitor units) were degraded with varying percentages (2%-95%) of randomly distributed dead single detectors (RDSs), randomly distributed dead detectormore » clusters (RDCs) of 2 mm diameter, and nonrandomly distributed dead detector disks (NRDDs) of varying diameter (4-16 mm). Correction algorithms were bidirectional linear interpolation (BLI), quad-directional linear interpolation (QLI), and a Laplacian solution (LS) method. Correction method failure was defined to occur if ring artifacts were present in the reconstructed phantom images from any linac or if the modulation transfer function (MTF) for any linac dropped below baseline with a p value, calculated with the two sample t test, of less than 0.01. Results: All correction methods failed at the same or lower RDC/RDS percentages and NRDD diameters for the 60 MU as for the 8 MU cases. The LS method tended to outperform or match the BLI and QLI methods. If ring artifacts anywhere in the images were considered unacceptable, the LS method failed for 60 MU at >33% RDS, >2% RDC, and >4 mm NRDD. If ring artifacts within 4 mm longitudinally of the phantom section interfaces were considered acceptable, the LS method failed for 60 MU at >90% RDS, >80% RDC, and >4 mm NRDD. LS failed due to MTF drop for 60 MU at >50% RDS, >25% RDC, and >4 mm NRDD. Conclusions: The LS method is superior to the BLI and QLI methods, and correction algorithm effectiveness decreases as imaging dose increases. All correction methods failed first due to ring artifacts and second due to MTF drop. If ring artifacts in axial slices within a 4 mm longitudinal distance from phantom section interfaces are acceptable, statistically significant loss in spatial resolution does not occur until over 25% of the EPID is covered in randomly distributed dead detectors, or NRDDs of 4 mm diameter are present.« less

Task partitioning in a robot swarm: object retrieval as a sequence of subtasks with direct object transfer.

PubMed

Pini, Giovanni; Brutschy, Arne; Scheidler, Alexander; Dorigo, Marco; Birattari, Mauro

2014-01-01

We study task partitioning in the context of swarm robotics. Task partitioning is the decomposition of a task into subtasks that can be tackled by different workers. We focus on the case in which a task is partitioned into a sequence of subtasks that must be executed in a certain order. This implies that the subtasks must interface with each other, and that the output of a subtask is used as input for the subtask that follows. A distinction can be made between task partitioning with direct transfer and with indirect transfer. We focus our study on the first case: The output of a subtask is directly transferred from an individual working on that subtask to an individual working on the subtask that follows. As a test bed for our study, we use a swarm of robots performing foraging. The robots have to harvest objects from a source, situated in an unknown location, and transport them to a home location. When a robot finds the source, it memorizes its position and uses dead reckoning to return there. Dead reckoning is appealing in robotics, since it is a cheap localization method and it does not require any additional external infrastructure. However, dead reckoning leads to errors that grow in time if not corrected periodically. We compare a foraging strategy that does not make use of task partitioning with one that does. We show that cooperation through task partitioning can be used to limit the effect of dead reckoning errors. This results in improved capability of locating the object source and in increased performance of the swarm. We use the implemented system as a test bed to study benefits and costs of task partitioning with direct transfer. We implement the system with real robots, demonstrating the feasibility of our approach in a foraging scenario.

Kobresia pygmaea pasture degradation and its response to increasing N deposition

NASA Astrophysics Data System (ADS)

Liu, Shibin; Schleuss, Per-Marten; Kuzyakov, Yakov

2016-04-01

Kobresia pygmaea is a dominant plant species on the Tibetan Plateau covering ca. one fifth of the total area. Severe degradation by overgrazing is ongoing at K. pygmaea pastures in recent decades. Nitrogen (N) deposition is also increasingly exacerbated across the Tibetan Plateau. Up to now the response of K. pygmaea pastures with increasing degradation to N deposition is unclear. We aimed at: (1) evaluating the effect of pasture degradation on carbon (C) and N contents of soil, root, microbial biomass and leachate, (2) determining N allocation to plant, soil and microbial biomass after N addition and (3) making an estimation of N storage and loss in Kobresia pasture. We used three Kobresia root mat types varying in their degradation stages: (1) living root mats, (2) dying root mats and (3) dead root mats. We also added two levels of 15NH415NO3 solution to simulate N deposition (control: 2.5 kg N/ha; deposition 50.9 kg N/ha) and traced the 15N in the soil-plant system. Leaching of NH4+, NO3- and DON were detected by homogeneously adding distilled water to each sample and collecting the leachate afterwards. Total N content lost by leaching increased 6.5 times following the degradation from living to dead root mats. This indicated that living Kobresia effectively decreased N loss from leaching due to N uptake by plants. The microbial biomass C to N (MBC/MBN) ratio narrowed from 10.2 to 7.5 and then to 5.0 for living, dying and dead root mats, respectively. This shows the degradation K. pygmaea shift the ecosystem from a N-limited to a C-limited status for microbes. Nitrogen addition increased above-ground plant biomass (AGB) as well as its total N content in living root mat while MBC and MBN were not affected. This shows K. pygmaea is more sensitive to N addition than microorganisms. N allocation (% of total N added) by AGB, below-ground plant biomass and soil in living root mats were 22.1%, 22.7% and 17.6%, respectively. No significant effect between these parameters was identified indicating that N allocation was independent to the giving amount of N. Up to 1.86 Mg N/ha were stored in living root mat (0-5 cm). In contrast, dead and dying root mats maintained about 2.0 Mg N/ha and 2.1 Mg N/ha, respectively. N loss in leachate of living root mat regarding a precipitation of 355 mm during growing season (equal to 85% of annual precipitation) was estimated to be around 3.6 kg N/ha (3.4 kg DON and 0.2 kg NH4-N). This amount was up to 6.5 times higher in dead root mat (23.6 kg N/ha with 19.1 kg NO3-N, 4 kg DON and 0.5 kg NH4-N). Therefore, degradation of K. pygmaea significantly increased N loss via leaching, especially NO3-N loss. We conclude N deposition facilitates the growth of K. pygmaea, which may positively affect plant productivity as well as C sequestration. In the absence of K. pygmaea, however, N deposition will lead to high N loss. Key words: Nitrogen allocation, Kobresia pygmaea, above-ground biomass, microbial biomass carbon and nitrogen

T1 weighted fat/water separated PROPELLER acquired with dual bandwidths.

PubMed

Rydén, Henric; Berglund, Johan; Norbeck, Ola; Avventi, Enrico; Skare, Stefan

2018-04-24

To describe a fat/water separated dual receiver bandwidth (rBW) spin echo PROPELLER sequence that eliminates the dead time associated with single rBW sequences. A nonuniform noise whitening by regularization of the fat/water inverse problem is proposed, to enable dual rBW reconstructions. Bipolar, flyback, and dual spin echo sequences were developed. All sequences acquire two echoes with different rBW without dead time. Chemical shift displacement was corrected by performing the fat/water separation in k-space, prior to gridding. The proposed sequences were compared to fat saturation, and single rBW sequences, in terms of SNR and CNR efficiency, using clinically relevant acquisition parameters. The impact of motion was investigated. Chemical shift correction greatly improved the image quality, especially at high resolution acquired with low rBW, and also improved motion estimates. SNR efficiency of the dual spin echo sequence was up to 20% higher than the single rBW acquisition, while CNR efficiency was 50% higher for the bipolar acquisition. Noise whitening was deemed necessary for all dual rBW acquisitions, rendering high image quality with strong and homogenous fat suppression. Dual rBW sequences eliminate the dead time present in single rBW sequences, which improves SNR efficiency. In combination with the proposed regularization, this enables highly efficient T1-weighted PROPELLER images without chemical shift displacement. © 2018 International Society for Magnetic Resonance in Medicine.

9 CFR 82.4 - General provisions.

Code of Federal Regulations, 2010 CFR

2010-01-01

... following articles may not be moved interstate from a quarantined area: (1) Dead birds and dead poultry...) Dressed carcasses of birds and poultry, and other dead birds and dead poultry, including any parts of the...

9 CFR 82.4 - General provisions.

Code of Federal Regulations, 2013 CFR

2013-01-01

... following articles may not be moved interstate from a quarantined area: (1) Dead birds and dead poultry...) Dressed carcasses of birds and poultry, and other dead birds and dead poultry, including any parts of the...

9 CFR 82.4 - General provisions.

Code of Federal Regulations, 2012 CFR

2012-01-01

... following articles may not be moved interstate from a quarantined area: (1) Dead birds and dead poultry...) Dressed carcasses of birds and poultry, and other dead birds and dead poultry, including any parts of the...

9 CFR 82.4 - General provisions.

Code of Federal Regulations, 2011 CFR

2011-01-01

... following articles may not be moved interstate from a quarantined area: (1) Dead birds and dead poultry...) Dressed carcasses of birds and poultry, and other dead birds and dead poultry, including any parts of the...

Comparative growth and development of spiders reared on live and dead prey.

PubMed

Peng, Yu; Zhang, Fan; Gui, Shaolan; Qiao, Huping; Hose, Grant C

2013-01-01

Scavenging (feeding on dead prey) has been demonstrated across a number of spider families, yet the implications of feeding on dead prey for the growth and development of individuals and population is unknown. In this study we compare the growth, development, and predatory activity of two species of spiders that were fed on live and dead prey. Pardosa astrigera (Lycosidae) and Hylyphantes graminicola (Lyniphiidae) were fed live or dead fruit flies, Drosophila melanogaster. The survival of P. astrigera and H. graminicola was not affected by prey type. The duration of late instars of P. astrigera fed dead prey were longer and mature spiders had less protein content than those fed live prey, whereas there were no differences in the rate of H. graminicola development, but the mass of mature spiders fed dead prey was greater than those fed live prey. Predation rates by P. astrigera did not differ between the two prey types, but H. graminicola had a higher rate of predation on dead than alive prey, presumably because the dead flies were easier to catch and handle. Overall, the growth, development and reproduction of H. graminicola reared with dead flies was better than those reared on live flies, yet for the larger P. astrigera, dead prey may suit smaller instars but mature spiders may be best maintained with live prey. We have clearly demonstrated that dead prey may be suitable for rearing spiders, although the success of the spiders fed such prey appears size- and species specific.

Comparative Growth and Development of Spiders Reared on Live and Dead Prey

PubMed Central

Peng, Yu; Zhang, Fan; Gui, Shaolan; Qiao, Huping; Hose, Grant C.

2013-01-01

Scavenging (feeding on dead prey) has been demonstrated across a number of spider families, yet the implications of feeding on dead prey for the growth and development of individuals and population is unknown. In this study we compare the growth, development, and predatory activity of two species of spiders that were fed on live and dead prey. Pardosa astrigera (Lycosidae) and Hylyphantes graminicola (Lyniphiidae) were fed live or dead fruit flies, Drosophila melanogaster. The survival of P. astrigera and H. graminicola was not affected by prey type. The duration of late instars of P. astrigera fed dead prey were longer and mature spiders had less protein content than those fed live prey, whereas there were no differences in the rate of H. graminicola development, but the mass of mature spiders fed dead prey was greater than those fed live prey. Predation rates by P. astrigera did not differ between the two prey types, but H. graminicola had a higher rate of predation on dead than alive prey, presumably because the dead flies were easier to catch and handle. Overall, the growth, development and reproduction of H. graminicola reared with dead flies was better than those reared on live flies, yet for the larger P. astrigera, dead prey may suit smaller instars but mature spiders may be best maintained with live prey. We have clearly demonstrated that dead prey may be suitable for rearing spiders, although the success of the spiders fed such prey appears size- and species specific. PMID:24386248

A system for the automated data-acquisition of fast transient signals in excitable membranes.

PubMed

Bustamante, J O

1988-01-01

This paper provides a description of a system for the acquisition of fast transient currents flowing across excitable membranes. The front end of the system consists of a CAMAC crate with plug-in modules. The modules provide control of CAMAC operations, analog to digital conversion, electronic memory storage and timing of events. The signals are transferred under direct memory access to an IBM PC microcomputer through a special-purpose interface. Voltage levels from a digital to analog board in the microcomputer are passed through multiplexers to produce the desired voltage pulse patterns to elicit the transmembrane currents. The dead time between consecutive excitatory voltage pulses is limited only by the computer data bus and the software characteristics. The dead time between data transfers can be reduced to the order of milliseconds, which is sufficient for most experiments with transmembrane ionic currents.

Dead-time optimized time-correlated photon counting instrument with synchronized, independent timing channels

NASA Astrophysics Data System (ADS)

Wahl, Michael; Rahn, Hans-Jürgen; Gregor, Ingo; Erdmann, Rainer; Enderlein, Jörg

2007-03-01

Time-correlated single photon counting is a powerful method for sensitive time-resolved fluorescence measurements down to the single molecule level. The method is based on the precisely timed registration of single photons of a fluorescence signal. Historically, its primary goal was the determination of fluorescence lifetimes upon optical excitation by a short light pulse. This goal is still important today and therefore has a strong influence on instrument design. However, modifications and extensions of the early designs allow for the recovery of much more information from the detected photons and enable entirely new applications. Here, we present a new instrument that captures single photon events on multiple synchronized channels with picosecond resolution and over virtually unlimited time spans. This is achieved by means of crystal-locked time digitizers with high resolution and very short dead time. Subsequent event processing in programmable logic permits classical histogramming as well as time tagging of individual photons and their streaming to the host computer. Through the latter, any algorithms and methods for the analysis of fluorescence dynamics can be implemented either in real time or offline. Instrument test results from single molecule applications will be presented.

Classification of phytoplankton cells as live or dead using the vital stains fluorescein diacetate and 5-chloromethylfluorescein diacetate.

PubMed

MacIntyre, Hugh L; Cullen, John J

2016-08-01

Regulations for ballast water treatment specify limits on the concentrations of living cells in discharge water. The vital stains fluorescein diacetate (FDA) and 5-chloromethylfluorescein diacetate (CMFDA) in combination have been recommended for use in verification of ballast water treatment technology. We tested the effectiveness of FDA and CMFDA, singly and in combination, in discriminating between living and heat-killed populations of 24 species of phytoplankton from seven divisions, verifying with quantitative growth assays that uniformly live and dead populations were compared. The diagnostic signal, per-cell fluorescence intensity, was measured by flow cytometry and alternate discriminatory thresholds were defined statistically from the frequency distributions of the dead or living cells. Species were clustered by staining patterns: for four species, the staining of live versus dead cells was distinct, and live-dead classification was essentially error free. But overlap between the frequency distributions of living and heat-killed cells in the other taxa led to unavoidable errors, well in excess of 20% in many. In 4 very weakly staining taxa, the mean fluorescence intensity in the heat-killed cells was higher than that of the living cells, which is inconsistent with the assumptions of the method. Applying the criteria of ≤5% false negative plus ≤5% false positive errors, and no significant loss of cells due to staining, FDA and FDA+CMFDA gave acceptably accurate results for only 8-10 of 24 species (i.e., 33%-42%). CMFDA was the least effective stain and its addition to FDA did not improve the performance of FDA alone. © 2016 The Authors. Journal of Phycology published by Wiley Periodicals, Inc. on behalf of Phycological Society of America.

The Effects of Antifoam Agent on Dead End Filtration Process

NASA Astrophysics Data System (ADS)

Mohamad Pauzi, S.; Ahmad, N.; Yahya, M. F.; Arifin, M. A.

2018-05-01

The formation of foam as a result from introducing gases during cell culture process in the bioprocess industry has indirectly affected the throughput of the product of interest. Due to that, antifoams were developed and established as one of the means to minimize the formation of foam in the cell culture. There are many types of antifoams but the silicone-type of antifoams are widely used in the bioprocess industry. Although the establishment of antifoam has aided the cell culture process, the impacts of its presence in the cell culture to the downstream process especially the dead end filtration is not widely discussed. The findings in the study emphasized on the dead end filtration performance that includes flux rate profile and the resulted filtration capacity. In this study, the concentrations of antifoam injected into the solution were varied from 0.2% v/v – 1.0% v/v and the solutions were filtered using constant flow method. The resulted maximum pressure readings and final flux rates indicated that the resistance exerted to the feed flow rate increased as the concentration of antifoam loaded in the solution increased. This later has led to the decline in the flux rates with percentage reduction between 32 – 68%. The calculated filter capacity for flux rate of 1000LMH ranged from 53 – 63L/m2 while it is in the range of 40 – 43L/m2 for flux rate of 2000LMH. The presence of antifoam agents in the feed load was determined to have negative effects on the dead end filtration performance and it may reduce the efficiency of the dead end filtration process.

Consequences of bioenergy wood extraction for landscape-level availability of habitat for dead wood-dependent organisms.

PubMed

Hiron, Matthew; Jonsell, Mats; Kubart, Ariana; Thor, Göran; Schroeder, Martin; Dahlberg, Anders; Johansson, Victor; Ranius, Thomas

2017-08-01

Stumps and slash resulting from forest clearcutting is used as a source of low-net-carbon energy, but there are concerns about the consequences of biofuel extraction on biodiversity. Logging residues constitute potentially important habitats, since a large part of forest biodiversity is dependent on dead wood. Here we used snapshot field data from a managed forest landscape (25 000 ha) to predict landscape scale population changes of dead wood dependent organisms after extraction of stumps and slash after clearcutting. We did this by estimating habitat availability for all observed dead wood-dependent beetles, macrofungi, and lichens (380 species) in the whole landscape. We found that 53% of species occurred in slash or stumps. For most species, population declines after moderate extraction (≤30%) were small (<10% decline) because they mainly occur on other dead wood types. However, some species were only recorded in slash and stumps. Red listed species were affected by slash and stump extraction (12 species), but less often than other species. Beetles and fungi were more affected by stump extraction, while lichens were more affected by slash extraction. For beetles and lichens, extraction of a combination of spruce, pine and birch resulted in larger negative effects than if only extracting spruce, while for fungi tree species had little effect. We conclude that extensive extraction decreases the amount of habitat to such extent that it may have negative consequences on species persistence at the landscape level. The negative consequences can be limited by extracting only slash, or only logging residues from spruce stands. Copyright © 2017 Elsevier Ltd. All rights reserved.

Off-line exhaled nitric oxide measurements in children.

PubMed

Barreto, M; Villa, M P; Martella, S; Falasca, C; Guglielmi, F; Pagani, J; Darder, M T; Ronchetti, R

2001-08-01

The concentration of exhaled nitric oxide (eNO) is a useful marker of asthmatic bronchial inflammation. eNO can now be measured away from the laboratory (off-line), even in children. Short exhalation maneuvers (8 sec) and small samples (1 L) of exhaled gas are probably sufficient in children, but more information is needed about the effect of different measurement conditions. As a preliminary step before conducting epidemiological studies in schoolchildren, we investigated the effects of expiratory flow, dead space, and expiratory time on eNO concentrations collected in 1-L mylar collection bags. We studied 101 cooperative subjects (62 males) aged 5-18 years (30 healthy volunteers, 51 asthmatics, and 20 children with various other respiratory diseases) in our pulmonary function laboratory. On-line and off-line eNO were compared in a single session, and analyzed with a Sievers NOA 280 nitric oxide analyzer. For both methods of collecting expired gas, subjects did a single exhalation without breath-holding against an expiratory pressure 10 cm H(2)O. We investigated the effects of expiratory flow, dead space, and exhalation time on eNO; we also compared on-line and off-line eNO measurements, and the repeatability of both techniques at a given flow rate. Expiratory flows of 58 mL/sec provided more reproducible data than lower flows (coefficient of repeatability 1.1 ppb for 58 mL/sec vs. 2.8 for 27 mL/sec vs. 5.7 for 18 mL/sec). eNO concentrations were about 25% higher in off-line than in on-line recordings if the initial 250 mL of exhaled gas were not eliminated, and 37% higher if exhalation lasted longer (16 sec vs. 8 sec). Eliminating 250 mL of dead space and shortening the filling time to 8 sec yielded off-line eNO values close to those on-line (geometric mean off-line eNO 14.4 ppb, 95% confidence interval: 12.2-17.0) vs. on-line eNO 13.8 ppb (95% confidence interval: 11.6-16.5). On-line and off-line results were highly correlated (r = 0.996, P = 0.000) and had similar coefficients of variation (on-line eNO 2.6%, off-line 2.8%). Neither agreement nor repeatability of eNO measurements were affected by disease status or baseline FEV(1) (% predicted values). Once standardized, the off-line eNO technique using 1-L gas collection bags will provide results similar to those recorded on-line. Copyright 2001 Wiley-Liss, Inc.

Congenital syphilis: trends in mortality and morbidity in the United States, 1999 through 2013.

PubMed

Su, John R; Brooks, Lesley C; Davis, Darlene W; Torrone, Elizabeth A; Weinstock, Hillard S; Kamb, Mary L

2016-03-01

Congenital syphilis (CS) results when an infected pregnant mother transmits syphilis to her unborn child prior to or at delivery. The severity of infection can range from a delivery at term without signs of infection to stillbirth or death after delivery. We sought to describe CS morbidity and mortality during 1999 through 2013. National CS case data reported to Centers for Disease Control and Prevention during 1999 through 2013 were analyzed. Cases were classified as dead (stillbirths and deaths up to 12 months after delivery), morbid (cases with strong [physical, radiographic, and/or nonserologic laboratory] evidence of CS), and nonmorbid (cases with a normal physical examination reported, without strong evidence of infection). Annual rates of these cases were calculated. Cases were compared using selected maternal and infant criteria. During 1999 through 2013, 6383 cases of CS were reported: 6.5% dead, 33.6% morbid, 53.9% nonmorbid, and 5.9% unknown morbidity; 81.8% of dead cases were stillbirths. Rates of dead, morbid, and nonmorbid cases all decreased over this time period, but the overall proportions that were dead or morbid cases did not significantly change. The overall case fatality ratio during 1999 through 2013 was 6.5%. Among cases of CS, maternal race/ethnicity was not associated with increased morbidity or death, although most cases (83%) occurred among black or Hispanic mothers. No or inadequate treatment for maternal syphilis, <10 prenatal visits, and maternal nontreponemal titer ≥1:8 increased the likelihood of a dead case; risk of a dead case increased with maternal nontreponemal titer (χ(2) for trend P < .001). Infants with CS born alive at <28 weeks' gestation (relative risk, 107.4; P < .001) or born weighing <1500 g (relative risk, 43.9; P < .001) were at greatly increased risk of death. CS remains an important preventable cause of perinatal morbidity and mortality, with comparable case fatality ratios during 1999 through 2013 (6.5%) and 1992 through 1998 (6.4%). Detection and treatment of syphilis early during pregnancy remain crucial to reducing CS morbidity and mortality. Published by Elsevier Inc.

Lithology of the long sediment record recovered by the ICDP Dead Sea Deep Drilling Project (DSDDP)

NASA Astrophysics Data System (ADS)

Neugebauer, Ina; Brauer, Achim; Schwab, Markus J.; Waldmann, Nicolas D.; Enzel, Yehouda; Kitagawa, Hiroyuki; Torfstein, Adi; Frank, Ute; Dulski, Peter; Agnon, Amotz; Ariztegui, Daniel; Ben-Avraham, Zvi; Goldstein, Steven L.; Stein, Mordechai

2014-10-01

The sedimentary sections that were deposited from the Holocene Dead Sea and its Pleistocene precursors are excellent archives of the climatic, environmental and seismic history of the Levant region. Yet, most of the previous work has been carried out on sequences of lacustrine sediments exposed at the margins of the present-day Dead Sea, which were deposited only when the lake surface level rose above these terraces (e.g. during the Last Glacial period) and typically are discontinuous due to major lake level variations in the past. Continuous sedimentation can only be expected in the deepest part of the basin and, therefore, a deep drilling has been accomplished in the northern basin of the Dead Sea during winter of 2010-2011 within the Dead Sea Deep Drilling Project (DSDDP) in the framework of the ICDP program. Approximately 720 m of sediment cores have been retrieved from two deep and several short boreholes. The longest profile (5017-1), revealed at a water depth of ˜300 m, reaches 455 m below the lake floor (blf, i.e. to ˜1175 m below global mean sea level) and comprises approximately the last 220-240 ka. The record covers the upper part of the Amora (penultimate glacial), the Last Interglacial Samra, the Last Glacial Lisan and the Holocene Ze'elim Formations and, therewith, two entire glacial-interglacial cycles. Thereby, for the first time, consecutive sediments deposited during the MIS 6/5, 5/4 and 2/1 transitions were recovered from the Dead Sea basin, which are not represented in sediments outcropping on the present-day lake shores. In this paper, we present essential lithological data including continuous magnetic susceptibility and geochemical scanning data and the basic stratigraphy including first chronological data of the long profile (5017-1) from the deep basin. The results presented here (a) focus on the correlation of the deep basin deposits with main on-shore stratigraphic units, thus providing a unique comprehensive stratigraphic framework for regional paleoenvironmental reconstruction, and (b) highlight the outstanding potential of the Dead Sea deep sedimentary archive to record hydrological changes during interglacial, glacial and transitional intervals.

9 CFR 82.4 - General provisions.

Code of Federal Regulations, 2014 CFR

2014-01-01

... moved interstate from a quarantined area: (1) Dead birds and dead poultry, including any parts of the... poultry, and other dead birds and dead poultry, including any parts of the birds or poultry, that are not...

Effect of Cypermethrin on the Growth of Ciliate Protozoan Paramecium caudatum

PubMed Central

Dutta, Joydeep

2015-01-01

Objective: The objective of this study is to assess the effect of cypermethrin on the growth of ciliate protozoan Paramecium caudatum. Materials and Methods: Monoxenic culture of P. caudatum, were exposed to different doses (0.01, 0.05, 0.1, 0.15, and 0.2 µg/L) of cypermethrin along with control for 24, 48, 72, and 96 h time interval. The total numbers of live and dead cells were counted after trypan blue staining in Neubauer hemocytometer. Results: Marked decrease in the number of living cells with the increase in the concentration of cypermethrin and with increasing exposure time intervals was recorded. Conclusion: The results indicate that cypermethrin is toxic to P. caudatum even at low concentrations when it enters in the aquatic system through runoff. PMID:26862268

Measuring and Modeling Sound Interference and Reverberation Time in Classrooms

NASA Astrophysics Data System (ADS)

Gumina, Kaitlyn; Martell, Eric

2015-04-01

Research shows that children, even those without hearing difficulties, are affected by poor classroom acoustics, especially children with hearing loss, learning disabilities, speech delay, and attention problems. Poor acoustics can come in a variety of forms, including destructive interference causing ``dead spots'' and extended Reverberation Times (RT), where echoes persist too long, interfering with further speech. In this research, I measured sound intensity at locations throughout three different types of classrooms at frequencies commonly associated with human speech to see what effect seating position has on intensity. I also used a program called Wave Cloud to model the time necessary for intensity to decrease by 60 decibels (RT50), both in idealized classrooms and in classrooms modeled on the ones I studied.

Deadly medicine.

PubMed

Bachrach, Susan

2007-01-01

This article discusses the methods the United States Holocaust Memorial Museum used to make an exhibition on the complex history of Nazi eugenics accessible to the museum's mass public and at the same time, provocative for special audiences consisting of professionals and students from the biomedical fields. Deadly Medicine: Creating the Master Race showed how both eugenics and related "euthanasia" programs in Nazi Germany helped pave the road to the Holocaust. The exhibition implicitly evoked the present-day appeal of biological explanations for human behavior and of new visions of human perfection. Educational programs used the exhibition as a springboard for discussions of bioethics and medical ethics.

Live/Dead Bacterial Spore Assay Using DPA-Triggered Tb Luminescence

NASA Technical Reports Server (NTRS)

Ponce, Adrian

2003-01-01

A method of measuring the fraction of bacterial spores in a sample that remain viable exploits DPA-triggered luminescence of Tb(3+) and is based partly on the same principles as those described earlier. Unlike prior methods for performing such live/dead assays of bacterial spores, this method does not involve counting colonies formed by cultivation (which can take days), or counting of spores under a microscope, and works whether or not bacterial spores are attached to other small particles (i.e., dust), and can be implemented on a time scale of about 20 minutes.

Six-state phase modulation for reduced crosstalk in a fiber optic gyroscope.

PubMed

Zhang, Chunxi; Zhang, Shaobo; Pan, Xiong; Jin, Jing

2018-04-16

Electrical crosstalk in an interferometric fiber-optic gyroscope (IFOG) is regarded as the most significant factor influencing dead bands. Here, we present a six-state modulation (SSM) technique to reduce crosstalk. Compared to conventional four-state modulation (FSM) or square-wave modulation (SWM), the SSM reduces the correlation between modulation voltage and demodulation reference by separating their fundamental frequencies, and thus reduces the bias error induced by crosstalk. The measured dead band of a 1500-m IFOG is approximately 0.02 °/h using FSM and approximately 0.08 °/h using SWM, whereas there is no evidence of dead band using SSM. The IFOG using SSM also exhibits better angular random walk (ARW) and bias instability performance compared to the same IFOG using FSM or SWM. These results verify the crosstalk reduction effect of SSM. In theory, by using the relative intensity noise (RIN) suppressing technique with the optimal modulation depth of 2π/3, the SSM can eliminate the crosstalk, which offers the potential for a high-performance IFOG with low noise, high sensitivity, wide dynamic range, and no dead band.

Assessment of yeast Saccharomyces cerevisiae component binding to Mycobacterium avium subspecies paratuberculosis using bovine epithelial cells.

PubMed

Li, Ziwei; You, Qiumei; Ossa, Faisury; Mead, Philip; Quinton, Margaret; Karrow, Niel A

2016-03-01

Since yeast Saccharomyces cerevisiae and its components are being used for the prevention and treatment of enteric diseases in different species, they may also be useful for preventing Johne's disease, a chronic inflammatory bowel disease of ruminants caused by Mycobacterium avium spp. paratuberculosis (MAP). This study aimed to identify potential yeast derivatives that may be used to help prevent MAP infection. The adherence of mCherry-labeled MAP to bovine mammary epithelial cell line (MAC-T cells) and bovine primary epithelial cells (BECs) co-cultured with yeast cell wall components (CWCs) from four different yeast strains (A, B, C and D) and two forms of dead yeast from strain A was investigated. The CWCs from all four yeast strains and the other two forms of dead yeast from strain A reduced MAP adhesion to MAC-T cells and BECs in a concentration-dependent manner after 6-h of exposure, with the dead yeast having the greatest effect. The following in vitro binding studies suggest that dead yeast and its' CWCs may be useful for reducing risk of MAP infection.

76 FR 53652 - Atlantic Highly Migratory Species; Atlantic Shark Management Measures

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-29

... an annual basis over that time series, an average of 780 were released alive and were 350 discarded dead. For oceanic whitetip sharks discarded over the time series, an average of 133 were released alive... time, NMFS is implementing the Recommendations as adopted at the 2010 ICCAT meeting. These...

20 CFR 404.721 - Evidence to presume a person is dead.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 20 Employees' Benefits 2 2014-04-01 2014-04-01 false Evidence to presume a person is dead. 404.721... person is dead. If you cannot prove the person is dead but evidence of death is needed, we will presume... person is presumed to be dead as set out in Federal law (5 U.S.C. 5565). Unless we have other evidence...

20 CFR 404.721 - Evidence to presume a person is dead.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Evidence to presume a person is dead. 404.721... person is dead. If you cannot prove the person is dead but evidence of death is needed, we will presume... person is presumed to be dead as set out in Federal law (5 U.S.C. 5565). Unless we have other evidence...

20 CFR 404.721 - Evidence to presume a person is dead.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 20 Employees' Benefits 2 2011-04-01 2011-04-01 false Evidence to presume a person is dead. 404.721... person is dead. If you cannot prove the person is dead but evidence of death is needed, we will presume... person is presumed to be dead as set out in Federal law (5 U.S.C. 5565). Unless we have other evidence...

20 CFR 404.721 - Evidence to presume a person is dead.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 20 Employees' Benefits 2 2012-04-01 2012-04-01 false Evidence to presume a person is dead. 404.721... person is dead. If you cannot prove the person is dead but evidence of death is needed, we will presume... person is presumed to be dead as set out in Federal law (5 U.S.C. 5565). Unless we have other evidence...

20 CFR 404.721 - Evidence to presume a person is dead.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 20 Employees' Benefits 2 2013-04-01 2013-04-01 false Evidence to presume a person is dead. 404.721... person is dead. If you cannot prove the person is dead but evidence of death is needed, we will presume... person is presumed to be dead as set out in Federal law (5 U.S.C. 5565). Unless we have other evidence...

Estimating dead-space fraction for secondary analyses of ARDS clinical trials

PubMed Central

Beitler, Jeremy R.; Thompson, B. Taylor; Matthay, Michael A.; Talmor, Daniel; Liu, Kathleen D.; Zhuo, Hanjing; Hayden, Douglas; Spragg, Roger G.; Malhotra, Atul

2015-01-01

Objective Pulmonary dead-space fraction is one of few lung-specific independent predictors of mortality from acute respiratory distress syndrome (ARDS). However, it is not measured routinely in clinical trials and thus altogether ignored in secondary analyses that shape future research directions and clinical practice. This study sought to validate an estimate of dead-space fraction for use in secondary analyses of clinical trials. Design Analysis of patient-level data pooled from ARDS clinical trials. Four approaches to estimate dead-space fraction were evaluated: three required estimating metabolic rate; one estimated dead-space fraction directly. Setting U.S. academic teaching hospitals. Patients Data from 210 patients across three clinical trials were used to compare performance of estimating equations with measured dead-space fraction. A second cohort of 3,135 patients from six clinical trials without measured dead-space fraction was used to confirm whether estimates independently predicted mortality. Interventions None. Measurements and Main Results Dead-space fraction estimated using the unadjusted Harris-Benedict equation for energy expenditure was unbiased (mean ± SD Harris-Benedict 0.59 ± 0.13; measured 0.60 ± 0.12). This estimate predicted measured dead-space fraction to within ± 0.10 in 70% of patients and ± 0.20 in 95% of patients. Measured dead-space fraction independently predicted mortality (OR 1.36 per 0.05 increase in dead-space fraction, 95% CI 1.10–1.68; p < .01). The Harris-Benedict estimate closely approximated this association with mortality in the same cohort (OR 1.55, 95% CI 1.21–1.98; p < .01) and remained independently predictive of death in the larger ARDSNet cohort. Other estimates predicted measured dead-space fraction or its association with mortality less well. Conclusions Dead-space fraction should be measured in future ARDS clinical trials to facilitate incorporation into secondary analyses. For analyses where dead-space fraction was not measured, the Harris-Benedict estimate can be used to estimate dead-space fraction and adjust for its association with mortality. PMID:25738857

Activity of Imipenem against Klebsiella pneumoniae Biofilms In Vitro and In Vivo

DTIC Science & Technology

2014-02-01

the channels were stained with Live/ Dead BacLight (Invitrogen) for 30 min to determine the live/dead status of bacteria in the remaining biofilms. Due...medium (Fig. 1). To quantify the killing effect of imipenem, we used the mini- mum biofilm eradication concentration (MBEC) assay (11) to determine the...each peg, treated and nontreated, were recovered by sonication, and the number of viable bacteria was determined by serial dilutions and plating. As

Sorption and precipitation of Mn2+ by viable and autoclaved Shewanella putrefaciens: Effect of contact time

NASA Astrophysics Data System (ADS)

Chubar, Natalia; Visser, Tom; Avramut, Cristina; de Waard, Helen

2013-01-01

The sorption of Mn(II) by viable and inactivated cells of Shewanella putrefaciens, a non-pathogenic, facultative anaerobic, gram-negative bacterium characterised as a Mn(IV) and Fe(III) reducer, was studied under aerobic conditions, as a function of pH, bacterial density and metal loading. During a short contact time (3-24 h), the adsorptive behaviour of live and dead bacteria toward Mn(II) was sufficiently similar, an observation that was reflected in the studies on adsorption kinetics at various metal loadings, effects of pH, bacteria density, isotherms and drifting of pH during adsorption. Continuing the experiment for an additional 2-30 days demonstrated that the Mn(II) sorption by suspensions of viable and autoclaved cells differed significantly from one another. The sorption to dead cells was characterised by a rapid equilibration and was described by an isotherm. In contrast, the sorption (uptake) to live bacteria exhibited a complex time-dependent uptake. This uptake began as adsorption and ion exchange processes followed by bioprecipitation, and it was accompanied by the formation of polymeric sugars (EPS) and the release of dissolved organic substances. FTIR, EXAFS/XANES and XPS demonstrated that manganese(II) phosphate was the main precipitate formed in 125 ml batches, which is the first evidence of the ability of microbes to synthesise manganese phosphates. XPS and XANES spectra did not detect Mn(II) oxidation. Although the release of protein-like compounds by the viable bacteria increased in the presence of Mn2+ (and, by contrast, the release of carbohydrates did not change), electrochemical analyses did not indicate any aqueous complexation of Mn(II) by the organic ligands.

Nutrient Dependence of RNase E Essentiality in Escherichia coli

PubMed Central

Tamura, Masaru; Moore, Christopher J.

2013-01-01

Escherichia coli cells normally require RNase E activity to form colonies (colony-forming ability [CFA]). The CFA-defective phenotype of cells lacking RNase E is partly reversed by overexpression of the related endoribonuclease RNase G or by mutation of the gene encoding the RNA helicase DeaD. We found that the carbon source utilization by rne deaD doubly mutant bacteria differs from that of rne+ cells and from that of cells mutated in deaD alone and that the loss of rne function in these bacteria limits conversion of the glycolytic pathway product phosphoenolpyruvate to the tricarboxylic acid (TCA) cycle intermediate oxaloacetic acid. We show that the mechanism underlying this effect is reduced production of the enzyme phosphoenolpyruvate carboxylase (PPC) and that adventitious overexpression of PPC, which facilitates phosphoenolpyruvate utilization and connects the glycolytic pathway with the TCA cycle, restored CFA to rne deaD mutant bacteria cultured on carbon sources that otherwise were unable to sustain growth. We further show that bacteria producing full-length RNase E, which allows formation of degradosomes, have nutritional requirements different from those of cells supplied with only the N-terminal catalytic region of RNase E and that mitigation of RNase E deficiency by overexpression of a related RNase, RNase G, is also affected by carbon source. Our results reveal previously unsuspected effects of RNase E deficiency and degradosome formation on nutrient utilization by E. coli cells. PMID:23275245

Structure of Irreversibly Adsorbed Star Polymers

NASA Astrophysics Data System (ADS)

Akgun, Bulent; Aykan, Meryem Seyma; Canavar, Seda; Satija, Sushil K.; Uhrig, David; Hong, Kunlun

Formation of irreversibly adsorbed polymer chains on solid substrates have a huge impact on the wetting, glass transition, aging and polymer chain mobility in thin films. In recent years there has been many reports on the formation, kinetics and dynamics of these layers formed by linear homopolymers. Recent studies showed that by varying the number of polymer arms and arm molecular weight one can tune the glass transition temperature of thin polymer films. Using polymer architecture as a tool, the behavior of thin films can be tuned between the behavior of linear chains and soft colloids. We have studied the effect of polymer chain architecture on the structure of dead layer using X-ray reflectivity (XR) and atomic force microscopy. Layer thicknesses and densities of flattened and loosely adsorbed chains has been measured for linear, 4-arm, and 8-arm star polymers with identical total molecular weight as a function of substrate surface energy, annealing temperature and annealing time. Star polymers have been synthesized using anionic polymerization. XR measurements showed that 8-arm star PS molecules form the densest and the thickest dead layers among these three molecules.

Extinction from a Rationalist Perspective

PubMed Central

Gallistel, C. R.

2012-01-01

The merging of the computational theory of mind and evolutionary thinking leads to a kind of rationalism, in which enduring truths about the world have become implicit in the computations that enable the brain to cope with the experienced world. The dead reckoning computation, for example, is implemented within the brains of animals as one of the mechanisms that enables them to learn where they are (Gallistel, 1990, 1995). It integrates a velocity signal with respect to a time signal. Thus, the manner in which position and velocity relate to one another in the world is reflected in the manner in which signals representing those variables are processed in the brain. I use principles of information theory and Bayesian inference to derive from other simple principles explanations for: 1) the failure of partial reinforcement to increase reinforcements to acquisition; 2) the partial reinforcement extinction effect; 3) spontaneous recovery; 4) renewal; 5) reinstatement; 6) resurgence (aka facilitated reacquisition). Like the principle underlying dead-reckoning, these principles are grounded in analytic considerations. They are the kind of enduring truths about the world that are likely to have shaped the brain's computations. PMID:22391153

Higher fungal diversity is correlated with lower CO2 emissions from dead wood in a natural forest.

PubMed

Yang, Chunyan; Schaefer, Douglas A; Liu, Weijie; Popescu, Viorel D; Yang, Chenxue; Wang, Xiaoyang; Wu, Chunying; Yu, Douglas W

2016-08-24

Wood decomposition releases almost as much CO2 to the atmosphere as does fossil-fuel combustion, so the factors regulating wood decomposition can affect global carbon cycling. We used metabarcoding to estimate the fungal species diversities of naturally colonized decomposing wood in subtropical China and, for the first time, compared them to concurrent measures of CO2 emissions. Wood hosting more diverse fungal communities emitted less CO2, with Shannon diversity explaining 26 to 44% of emissions variation. Community analysis supports a 'pure diversity' effect of fungi on decomposition rates and thus suggests that interference competition is an underlying mechanism. Our findings extend the results of published experiments using low-diversity, laboratory-inoculated wood to a high-diversity, natural system. We hypothesize that high levels of saprotrophic fungal biodiversity could be providing globally important ecosystem services by maintaining dead-wood habitats and by slowing the atmospheric contribution of CO2 from the world's stock of decomposing wood. However, large-scale surveys and controlled experimental tests in natural settings will be needed to test this hypothesis.

Higher fungal diversity is correlated with lower CO2 emissions from dead wood in a natural forest

PubMed Central

Yang, Chunyan; Schaefer, Douglas A.; Liu, Weijie; Popescu, Viorel D.; Yang, Chenxue; Wang, Xiaoyang; Wu, Chunying; Yu, Douglas W.

2016-01-01

Wood decomposition releases almost as much CO2 to the atmosphere as does fossil-fuel combustion, so the factors regulating wood decomposition can affect global carbon cycling. We used metabarcoding to estimate the fungal species diversities of naturally colonized decomposing wood in subtropical China and, for the first time, compared them to concurrent measures of CO2 emissions. Wood hosting more diverse fungal communities emitted less CO2, with Shannon diversity explaining 26 to 44% of emissions variation. Community analysis supports a ‘pure diversity’ effect of fungi on decomposition rates and thus suggests that interference competition is an underlying mechanism. Our findings extend the results of published experiments using low-diversity, laboratory-inoculated wood to a high-diversity, natural system. We hypothesize that high levels of saprotrophic fungal biodiversity could be providing globally important ecosystem services by maintaining dead-wood habitats and by slowing the atmospheric contribution of CO2 from the world’s stock of decomposing wood. However, large-scale surveys and controlled experimental tests in natural settings will be needed to test this hypothesis. PMID:27553882

Solid Propulsion De-Orbiting and Re-Orbiting

NASA Astrophysics Data System (ADS)

Schonenborg, R. A. C.; Schoyer, H. F. R.

2009-03-01

With many "innovative" de-orbit systems (e.g. tethers, aero breaking, etc.) and with natural de-orbit, the place of impact of unburned spacecraft debris on Earth can not be determined accurately. The idea that satellites burn up completely upon re-entry is a common misunderstanding. To the best of our knowledge only rocket motors are capable of delivering an impulse that is high enough, to conduct a de-orbit procedure swiftly, hence to de-orbit at a specific moment that allows to predict the impact point of unburned spacecraft debris accurately in remote areas. In addition, swift de-orbiting will reduce the on-orbit time of the 'dead' satellite, which reduces the chance of the dead satellite being hit by other dead or active satellites, while spiralling down to Earth during a slow, 25 year, or more, natural de-orbit process. Furthermore the reduced on-orbit time reduces the chance that spacecraft batteries, propellant tanks or other components blow up and also reduces the time that the object requires tracking from Earth.The use of solid propellant for the de-orbiting of spacecraft is feasible. The main advantages of a solid propellant based system are the relatively high thrust and the facts that the system can be made autonomous quite easily and that the system can be very reliable. The latter is especially desirable when one wants to de-orbit old or 'dead' satellites that might not be able to rely anymore on their primary systems. The disadvantage however, is the addition of an extra system to the spacecraft as well as a (small) mass penalty. [1]This paper describes the above mentioned system and shows as well, why such a system can also be used to re-orbit spacecraft in GEO, at the end of their life to a graveyard orbit.Additionally the system is theoretically compared to an existing system, of which performance data is available.A swift market analysis is performed as well.

Simulated long-term effects of varying tree retention on wood production, dead wood and carbon stock changes.

PubMed

Santaniello, Francesca; Djupström, Line B; Ranius, Thomas; Weslien, Jan; Rudolphi, Jörgen; Sonesson, Johan

2017-10-01

Boreal forests are an important source of timber and pulp wood, but provide also other products and services. Utilizing a simulation program and field data from a tree retention experiment in a Scots pine forest in central Sweden, we simulated the consequences during the following 100 years of various levels of retention on production of merchantable wood, dead wood input (as a proxy for biodiversity), and carbon stock changes. At the stand level, wood production decreased with increased retention levels, while dead wood input and carbon stock increased. We also compared 12 scenarios representing a land sharing/land sparing gradient. In each scenario, a constant volume of wood was harvested with a specific level of retention in a 100-ha landscape. The area not needed to reach the defined volume was set-aside during a 100-year rotation period, leading to decreasing area of set-asides with increasing level of retention across the 12 scenarios. Dead wood input was positively affected by the level of tree retention whereas the average carbon stock decreased slightly with increasing level of tree retention. The scenarios will probably vary in how they favor species preferring different substrates. Therefore, we conclude that a larger variation of landscape-level conservation strategies, also including active creation of dead wood, may be an attractive complement to the existing management. Copyright © 2017 Elsevier Ltd. All rights reserved.

Out of the body: embodiment and its vicissitudes.

PubMed

Connolly, Angela

2013-11-01

Body-mind dualism and the consequent neglect of the body of the analyst can have important negative effects on the analytical process leading all too often to misinterpretations of the analysand's verbal and non-verbal communications and to disturbances of analytical temporality. This is intensified when we are dealing with individuals where disembodiment and states of psychic deadness are central features. The paper explores the philosophical roots of the idea of a disembodied mind and the way in which this impacts our relationship with the world. While André Green's concept of the dead mother and disturbances in the sense of self-agency have been held to play an important role in states of psychic deadness, I suggest that it is rather disturbances in the sense of body ownership and of the body image which are more central. The paper then discusses the particular kinds of countertransference that can be evoked in the analyst when we find ourselves dealing with this type of patient and suggests how we can use our embodied countertransference to become aware of and elaborate our own feelings of deadness in order to overcome the loss of temporality that is characteristic of such states. This is illustrated with reference to my work with a young man with a masochistic perversion and a severe disturbance of the body image with an accompanying profound sense of psychic deadness. © 2013, The Society of Analytical Psychology.

Keystone-designed buried de-epithelialized flap

PubMed Central

Kim, Hoon; Ryu, Wan Cheol; Yoon, Chi Sun; Kim, Kyu Nam

2017-01-01

Abstract Effective obliteration of dead space after reconstructive surgery facilitates a good cosmetic outcome and prevention of delayed wound healing and recurrent infection. We evaluated the efficacy of a keystone-designed buried de-epithelialized (KBD) flap for the obliteration of small to moderately sized surgical dead spaces. We reviewed the medical records of patients who received a KBD flap following removal of a mass or debridement of necrotic tissue from September 2015 to February 2016. The diagnosis, site, dead space dimensions, flap width, drain data, complications, and follow-up duration were recorded. Twenty-eight KBD flaps were evaluated, including 9 cases of fat necrosis, 7 cases of epidermal cyst, and 12 cases of lipoma. Dead space dimensions ranged from 2 × 1.5 × 1 cm to 10 × 5 × 3 cm, with a mean depth of 2.01 cm. Flap sizes ranged from 2.5 × 1 cm to 11 × 3 cm, with a mean flap width of 2.01 cm. No postoperative complications, such as seroma or hematoma, occurred. The cosmetic results were favorable, and all patients were satisfied with their final outcomes. The KBD flap is useful for the obliteration of small to moderately sized surgical dead spaces both spatially and physiologically and shows excellent cosmetic outcomes. PMID:28538418

On the fragility of fractional-order PID controllers for FOPDT processes.

PubMed

Padula, Fabrizio; Visioli, Antonio

2016-01-01

This paper analyzes the fragility issue of fractional-order proportional-integral-derivative controllers applied to integer first-order plus-dead-time processes. In particular, the effects of the variations of the controller parameters on the achieved control system robustness and performance are investigated. Results show that this kind of controllers is more fragile with respect to the standard proportional-integral-derivative controllers and therefore a significant attention should be paid by the user in their tuning. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

The Effective Fracture Toughness of Aluminum at Rapid Heating Rates.

DTIC Science & Technology

1987-12-01

Stress Versus Time Relation During Test Under HWdraulic (Tinius-Olsen) Loading Device 32 11. Creep Rupture Tester ( SATEC ) Drawing ...... 33 12. SEN...1B7 Machine Corp Creep Frame SATEC C C-3053-P 12,000 Load Cell MTS 661.20A 271 5500 lb .02% Load Cell Interface 1220BF 34279B 25000 lb 1.6% Extenso- MIS... SATEC creep frame. A drawing of the creep frame can be seen in Figure 11. The samples were placed in the frame and the dead weight load was applied

Effect of Water Surface Salinity on Evaporation: The Case of a Diluted Buoyant Plume Over the Dead Sea

NASA Astrophysics Data System (ADS)

Mor, Z.; Assouline, S.; Tanny, J.; Lensky, I. M.; Lensky, N. G.

2018-03-01

Evaporation from water bodies strongly depends on surface water salinity. Spatial variation of surface salinity of saline water bodies commonly occurs across diluted buoyant plumes fed by freshwater inflows. Although mainly studied at the pan evaporation scale, the effect of surface water salinity on evaporation has not yet been investigated by means of direct measurement at the scale of natural water bodies. The Dead Sea, a large hypersaline lake, is fed by onshore freshwater springs that form local diluted buoyant plumes, offering a unique opportunity to explore this effect. Surface heat fluxes, micrometeorological variables, and water temperature and salinity profiles were measured simultaneously and directly over the salty lake and over a region of diluted buoyant plume. Relatively close meteorological conditions prevailed in the two regions; however, surface water salinity was significantly different. Evaporation rate from the diluted plume was occasionally 3 times larger than that of the main salty lake. In the open lake, where salinity was uniform with depth, increased wind speed resulted in increased evaporation rate, as expected. However, in the buoyant plume where diluted brine floats over the hypersaline brine, wind speed above a threshold value (˜4 m s-1) caused a sharp decrease in evaporation probably due to mixing of the stratified plume and a consequent increase in the surface water salinity.

Water quality modeling in the dead end sections of drinking water (Supplement)

EPA Pesticide Factsheets

Dead-end sections of drinking water distribution networks are known to be problematic zones in terms of water quality degradation. Extended residence time due to water stagnation leads to rapid reduction of disinfectant residuals allowing the regrowth of microbial pathogens. Water quality models developed so far apply spatial aggregation and temporal averaging techniques for hydraulic parameters by assigning hourly averaged water demands to the main nodes of the network. Although this practice has generally resulted in minimal loss of accuracy for the predicted disinfectant concentrations in main water transmission lines, this is not the case for the peripheries of the distribution network. This study proposes a new approach for simulating disinfectant residuals in dead end pipes while accounting for both spatial and temporal variability in hydraulic and transport parameters. A stochastic demand generator was developed to represent residential water pulses based on a non-homogenous Poisson process. Dispersive solute transport was considered using highly dynamic dispersion rates. A genetic algorithm was used tocalibrate the axial hydraulic profile of the dead-end pipe based on the different demand shares of the withdrawal nodes. A parametric sensitivity analysis was done to assess the model performance under variation of different simulation parameters. A group of Monte-Carlo ensembles was carried out to investigate the influence of spatial and temporal variation

Water Quality Modeling in the Dead End Sections of Drinking ...

EPA Pesticide Factsheets

Dead-end sections of drinking water distribution networks are known to be problematic zones in terms of water quality degradation. Extended residence time due to water stagnation leads to rapid reduction of disinfectant residuals allowing the regrowth of microbial pathogens. Water quality models developed so far apply spatial aggregation and temporal averaging techniques for hydraulic parameters by assigning hourly averaged water demands to the main nodes of the network. Although this practice has generally resulted in minimal loss of accuracy for the predicted disinfectant concentrations in main water transmission lines, this is not the case for the peripheries of a distribution network. This study proposes a new approach for simulating disinfectant residuals in dead end pipes while accounting for both spatial and temporal variability in hydraulic and transport parameters. A stochastic demand generator was developed to represent residential water pulses based on a non-homogenous Poisson process. Dispersive solute transport was considered using highly dynamic dispersion rates. A genetic algorithm was used to calibrate the axial hydraulic profile of the dead-end pipe based on the different demand shares of the withdrawal nodes. A parametric sensitivity analysis was done to assess the model performance under variation of different simulation parameters. A group of Monte-Carlo ensembles was carried out to investigate the influence of spatial and temporal variations

Implications of S1 tephra findings in Dead Sea and Tayma palaeolake sediments for marine reservoir age estimation and palaeoclimate synchronisation

NASA Astrophysics Data System (ADS)

Neugebauer, Ina; Wulf, Sabine; Schwab, Markus J.; Serb, Johanna; Plessen, Birgit; Appelt, Oona; Brauer, Achim

2017-08-01

Here we report on the first findings of a cryptotephra in the Holocene lacustrine sediment records of the Dead Sea and Tayma palaeolake (NW Arabian Peninsula). The major element glass composition of this rhyolitic tephra is identical to the distal 'S1' tephra layer identified in the Yammoûneh palaeolake (Lebanon), in a marine sediment record from the SE Levantine basin and in the Sodmein Cave archaeological site in Egypt. The S1 tephra corresponds to the early Holocene 'Dikkartın' dome eruption of the Erciyes Dağ volcano in central Anatolia (Turkey) and has been dated in the marine record at 8830 ± 140 cal yr BP. We present new age estimates of the S1 tephra based on radiocarbon dating of terrestrial plant remains and pollen concentrates revealing ages of 8939 ± 83 cal yr BP in the Dead Sea sediments and 9041 ± 254 cal yr BP in Tayma. The precise date from the Dead Sea allows refining the early Holocene marine reservoir age in the SE Levantine Sea to ca. 320 ± 50 years. Synchronisation of marine and terrestrial palaeoclimate records in the eastern Mediterranean region using the S1 tephra further suggests a time-transgressive expansion of the early Holocene humid period.

RNA-based analyses reveal fungal communities structured by a senescence gradient in the moss Dicranum scoparium and the presence of putative multi-trophic fungi.

PubMed

Chen, Ko-Hsuan; Liao, Hui-Ling; Arnold, A Elizabeth; Bonito, Gregory; Lutzoni, François

2018-06-01

Diverse plant-associated fungi are thought to have symbiotrophic and saprotrophic states because they can be isolated from both dead and living plant tissues. However, such tissues often are separated in time and space, and fungal activity at various stages of plant senescence is rarely assessed directly in fungal community studies. We used fungal ribosomal RNA metatranscriptomics to detect active fungal communities across a natural senescence gradient within wild-collected gametophytes of Dicranum scoparium (Bryophyta) to understand the distribution of active fungal communities in adjacent living, senescing and dead tissues. Ascomycota were active in all tissues across the senescence gradient. By contrast, Basidiomycota were prevalent and active in senescing and dead tissues. Several fungi were detected as active in living and dead tissues, suggesting their capacity for multi-trophy. Differences in community assembly detected by metatranscriptomics were echoed by amplicon sequencing of cDNA and compared to culture-based inferences and observation of fungal fruit bodies in the field. The combination of amplicon sequencing of cDNA and metatranscriptomics is promising for studying symbiotic systems with complex microbial diversity, allowing for the simultaneous detection of their presence and activity. © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

Development of 72/84kV Dry Air Insulated Dead Tank Type VCB

NASA Astrophysics Data System (ADS)

Saito, Hitoshi; Nagatake, Kazuhiro; Komatsu, Hideki; Takeshita, Yukihiro; Matsui, Yoshihiko; Katsumata, Kiyohito; Sakaki, Masayuki

As a circuit breaker for over 84kV, SF6 gas circuit breaker (GCB) has been used for a long time, in virtue of its excellent characteristics as arc extinction and insulating medium. Although, SF6 gas has very high global warming potential (GWP) of 23,900, and it was designated to regulation object in COP3 in Kyoto in 1997. A lot of efforts have been done to reduce the amount of SF6 gas usage and emission from conventional equipments. On the other hand, SF6 gas free equipment has been researching and one strong candidate is air-insulated type switchgears with vacuum interrupters. In last few years, air-insulated switchgears, which include GIS, Cubicle type GIS (C-GIS) and dead tank type VCB, have been developed in succession. So far, we have already more than three years operation record for the air-insulated dead tank type VCB, and over 100 units is in-service in power systems. Recently, VCB technology, that is essential for SF6 gas-free equipments, has been advanced in the field of high-voltage, large current interruption and environment-conscious design. In this paper, the advanced dead tank type VCB and its technology is descried.

Lower crustal flow and the role of shear in basin subsidence: An example from the Dead Sea basin

USGS Publications Warehouse

Al-Zoubi, A.; ten Brink, Uri S.

2002-01-01

We interpret large-scale subsidence (5–6 km depth) with little attendant brittle deformation in the southern Dead Sea basin, a large pull-apart basin along the Dead Sea transform plate boundary, to indicate lower crustal thinning due to lower crustal flow. Along-axis flow within the lower crust could be induced by the reduction of overburden pressure in the central Dead Sea basin, where brittle extensional deformation is observed. Using a channel flow approximation, we estimate that lower crustal flow would occur within the time frame of basin subsidence if the viscosity is ≤7×1019–1×1021 Pa s, a value compatible with the normal heat flow in the region. Lower crustal viscosity due to the strain rate associated with basin extension is estimated to be similar to or smaller than the viscosity required for a channel flow. However, the viscosity under the basin may be reduced to 5×1017–5×1019 Pa s by the enhanced strain rate due to lateral shear along the transform plate boundary. Thus, lower crustal flow facilitated by shear may be a viable mechanism to enlarge basins and modify other topographic features even in the absence of underlying thermal anomalies.

Long-term dead wood changes in a Sierra Nevada mixed conifer forest: habitat and fire hazard implications

Treesearch

Eric E. Knapp

2015-01-01

Dead trees play an important role in forests, with snags and coarse woody debris (CWD) used by many bird and mammal species for nesting, resting, or foraging. However, too much dead wood can also contribute to extreme fire behavior. This tension between dead wood as habitat and dead wood as fuel has raised questions about appropriate quantities in fire-dependent...

Never Declared Brain Dead Potential Organ Donors-An Additional Source of Donor Organs?

PubMed

Webster, Patricia A; Markham, Lori E

2018-03-01

Patients never declared brain dead may represent an additional source of donor organs. To determine the number of likely brain dead potential donors who are never declared brain dead and to compare them with brain dead and donation after cardiac death potential organ donors. This study was a retrospective chart review of all catastrophically brain-injured patients referred to a single-organ procurement organization (OPO) over a 4-year period. This study identified 159 likely brain dead potential organ donors, 902 brain dead potential organ donors, and 357 potential donation after circulatory death donors over a 4-year period. None. This study did not predetermine outcome measures before data collection because the study group, likely brain dead potential organ donors, had not previously been described. Likely brain dead potential donors were significantly older than brain dead potential donors ( P < .0001) but were otherwise not different demographically. They were more likely to be a late referral to the OPO ( P < .0001) and less likely to be in the donor registry ( P < .0001). The most commonly identified factors associated with a failure to declare brain death were an unwillingness to continue supportive care by the family, premention of donation, a nontimely imminent death referral, known prior objection to donation, terminal instability, and a lack of cooperation with the OPO.

The ecosystem service value of living versus dead biogenic reef

NASA Astrophysics Data System (ADS)

Sheehan, E. V.; Bridger, D.; Attrill, M. J.

2015-03-01

Mixed maerl beds (corralline red algae) comprise dead thalli with varying amounts of live maerl fragments, but previously it was not known whether the presence of the live maerl increases the ecosystem service 'habitat provision' of the dead maerl for the associated epibenthos. A 'flying array' towed sled with high definition video was used to film transects of the epibenthos in dead maerl and mixed maerl beds in two locations to the north and south of the English Channel (Falmouth and Jersey). Mixed maerl beds supported greater number of taxa and abundance than dead beds in Falmouth, while in Jersey, mixed and dead beds supported similar number of taxa and dead beds had a greater abundance of epifauna. Scallops tended to be more abundant on mixed beds than dead beds. Tube worms were more abundant on mixed beds in Falmouth and dead beds in Jersey. An increasing percentage occurrence of live maerl thalli correlated with increasing number of taxa in Falmouth but not Jersey. It was concluded that while live thalli can increase the functional role of dead maerl beds for the epibenthos, this is dependent on location and response variable. As a result of this work, maerl habitat in SE Jersey has been protected from towed demersal fishing gear.

The Effect of Standardized Interviews on Organ Donation.

PubMed

Corman Dincer, Pelin; Birtan, Deniz; Arslantas, Mustafa Kemal; Tore Altun, Gulbin; Ayanoglu, Hilmi Omer

2018-03-01

Organ donation is the most important stage for organ transplant. Studies reveal that attitudes of families of brain-dead patients toward donation play a significant role in their decision. We hypothesized that supporting family awareness about the meaning of organ donation, including saving lives while losing a loved one, combined with being informed about brain death and the donation process must be maintained by intensive care unit physicians through standardized interviews and questionnaires to increase the donation rate. We retrospectively evaluated the final decisions of families of 52 brain-dead donors treated at our institution between 2014 and 2017. Data underwent descriptive analyses. The standard interview content was generated after literature search results were reviewed by the authors. Previously, we examined the impact of standardized interviews done by intensive care unit physicians with relatives of potential brain-dead donors regarding decisions to donate or reasons for refusing organ donation. After termination of that study, interviews were done according to the intensivist's orientation, resulting in significantly decreased donation rates. Standardized interviews were then started again, resulting in increased donation rates. Of 17 families who participated in standardized interviews, 5 families (29.4%) agreed to donate organs of their brain-dead relatives. In the other group of families, intensivists governed informing the families of donation without standardized interviews. In this group of 35 families, 5 families (14.3%) approved organ donation. The decision regarding whether to agree to organ donation was statistically different between the 2 family groups (P < .05). Conducting a standard interview between relatives of brain-dead donors and the intensivists, facilitating visits between relatives and the brain-dead patients, and informing relatives about the donation process resulted in an increased rate of organ donation compared with routine protocols.

Response of nematode-trapping fungi to organic substrates in a coastal grassland soil.

PubMed

Nguyen, Vi L; Bastow, Justin L; Jaffee, Bruce A; Strong, Don R

2007-07-01

To understand why Arthrobotrys oligospora and other nematode-trapping fungi are common and sometimes abundant in the coastal grassland soils of the Bodega Marine Reserve (BMR, Sonoma County, CA), we examined how resident trapping fungi responded to the addition of eight organic substrates (lupine leaves, grass leaves, dead isopods, dead moth larvae, isopod faeces, deer faeces, shrimp shells, and powdered chitin). We were especially interested in the effects of dead isopods because isopods are abundant at BMR and because previous studies had documented strong responses of A. oligospora to other arthropods (dead moth larvae). Soil from BMR was packed into vials (40 g dry mass equivalent per vial with water potential at -230 kPa and bulk density at 0.9 gcm(-3)), and one substrate or no substrate was added to the soil surface. After 30 d at 20 degrees C, trapping fungi were quantified by dilution plating and most probable number procedures. The response of A. oligospora was inversely related to substrate carbon:nitrogen (C:N) ratio: substrates with low C:N ratios (dead isopods, lupine leaves, dead moth larvae) usually caused large increases in A. oligospora whereas those with higher C:N ratios (isopod faeces, deer faeces, grass leaves) did not. An exception was chitin powder, which had a low C:N ratio, but which did not cause A. oligospora to proliferate. Responses of A. oligospora were directly related to the quantity of nitrogen added with each substrate, and those substrates that caused large increases in resident nematodes usually caused large increases in A. oligospora. Other trapping fungi did not respond as strongly as A. oligospora.

ROSSBY WAVE INSTABILITY AT DEAD ZONE BOUNDARIES IN THREE-DIMENSIONAL RESISTIVE MAGNETOHYDRODYNAMICAL GLOBAL MODELS OF PROTOPLANETARY DISKS

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

Lyra, Wladimir; Mac Low, Mordecai-Mark, E-mail: wlyra@jpl.nasa.gov, E-mail: mordecai@amnh.org

It has been suggested that the transition between magnetorotationally active and dead zones in protoplanetary disks should be prone to the excitation of vortices via Rossby wave instability (RWI). However, the only numerical evidence for this has come from alpha disk models, where the magnetic field evolution is not followed, and the effect of turbulence is parameterized by Laplacian viscosity. We aim to establish the phenomenology of the flow in the transition in three-dimensional resistive-magnetohydrodynamical models. We model the transition by a sharp jump in resistivity, as expected in the inner dead zone boundary, using the PENCIL CODE to simulatemore » the flow. We find that vortices are readily excited in the dead side of the transition. We measure the mass accretion rate finding similar levels of Reynolds stress at the dead and active zones, at the {alpha} Almost-Equal-To 10{sup -2} level. The vortex sits in a pressure maximum and does not migrate, surviving until the end of the simulation. A pressure maximum in the active zone also triggers the RWI. The magnetized vortex that results should be disrupted by parasitical magneto-elliptic instabilities, yet it subsists in high resolution. This suggests that either the parasitic modes are still numerically damped or that the RWI supplies vorticity faster than they can destroy it. We conclude that the resistive transition between the active and dead zones in the inner regions of protoplanetary disks, if sharp enough, can indeed excite vortices via RWI. Our results lend credence to previous works that relied on the alpha-disk approximation, and caution against the use of overly reduced azimuthal coverage on modeling this transition.« less

A Metagenomic Assembly-Based Approach to Decoding Taxa in the Dead Zone

NASA Astrophysics Data System (ADS)

Thrash, C.; Baker, B.; Seitz, K.; Gillies, L.; Temperton, B.; Rabalais, N. N.; Mason, O. U.

2016-02-01

Coastal regions of eutrophication-driven oxygen depletion are widespread and increasing in number. Also known as dead zones, these regions take their name from the deleterious effects of hypoxia (dissolved oxygen less than 2 mg/L) on shrimp, demersal fish, and other animal life. Dead zones result from nutrient enrichment of primary production, concomitant consumption by chemoorganotrophic aerobic microorganisms, and strong stratification that prevents ventilation of bottom water. One of the largest dead zones in the world occurs seasonally in the northern Gulf of Mexico (nGOM), where hypoxia can reach up to 22,000 square kilometers. To explore the underlying genomic variation and metabolic potential of microorganisms in hypoxia, we performed metagenomic and metatranscriptomic sequencing on six samples from the 2013 nGOM dead zone from both hypoxic and oxic bottom waters. Over 217 Mb of sequence was assembled into contigs of at least 3 kb with IDBA-UD, with 72 greater than 100 kb, and the largest 495 kb in length. Annotation by IMG recovered over 224 thousand genes in these contigs. Binning with tetra-ESOM and quality filtering based on relative coverage of sample-specific reads led to the recovery of 83 partial to near complete (31 over 70%) high-quality genomes. These metagenomes represent key microbial taxa previously determined to be numerically abundant from 16S rRNA data, such as Thaumarcheaota, Marine Group II Euryarchaeota, SAR406, Synechococcus spp., Actinobacteria, and Planctomycetes. Ongoing work includes the recruitment of metatranscriptomic data to binned contigs for evaluation of relative gene expression, metabolic reconstruction, and comparative genomics with related organisms elsewhere in the global oceans. These data will provide us with detailed information regarding the metabolic potential and activity of many of the key players in the nGOM dead zone.

Nonlinear dead water resistance at subcritical speed

NASA Astrophysics Data System (ADS)

Grue, John

2015-08-01

The dead water resistance F 1 = /1 2 C d w ρ S U 2 (ρ fluid density, U ship speed, S wetted body surface, Cdw resistance coefficient) on a ship moving at subcritical speed along the upper layer of a two-layer fluid is calculated by a strongly nonlinear method assuming potential flow in each layer. The ship dimensions correspond to those of the Polar ship Fram. The ship draught, b0, is varied in the range 0.25h0-0.9h0 (h0 the upper layer depth). The calculations show that Cdw/(b0/h0)2 depends on the Froude number only, in the range close to critical speed, Fr = U/c0 ˜ 0.875-1.125 (c0 the linear internal long wave speed), irrespective of the ship draught. The function Cdw/(b0/h0)2 attains a maximum at subcritical Froude number depending on the draught. Maximum Cdw/(b0/h0)2 becomes 0.15 for Fr = 0.76, b0/h0 = 0.9, and 0.16 for Fr = 0.74, b0/h0 = 1, where the latter extrapolated value of the dead water resistance coefficient is about 60 times higher than the frictional drag coefficient and relevant for the historical dead water observations. The nonlinear Cdw significantly exceeds linear theory (Fr < 0.85). The ship generated waves have a wave height comparable to the upper layer depth. Calculations of three-dimensional wave patterns at critical speed compare well to available laboratory experiments. Upstream solitary waves are generated in a wave tank of finite width, when the layer depths differ, causing an oscillation of the force. In a wide ocean, a very wide wave system develops at critical speed. The force approaches a constant value for increasing time.

Net carbon flux of dead wood in forests of the Eastern US.

PubMed

Woodall, C W; Russell, M B; Walters, B F; D'Amato, A W; Fraver, S; Domke, G M

2015-03-01

Downed dead wood (DDW) in forest ecosystems is a C pool whose net flux is governed by a complex of natural and anthropogenic processes and is critical to the management of the entire forest C pool. As empirical examination of DDW C net flux has rarely been conducted across large scales, the goal of this study was to use a remeasured inventory of DDW C and ancillary forest attributes to assess C net flux across forests of the Eastern US. Stocks associated with large fine woody debris (diameter 2.6-7.6 cm) decreased over time (-0.11 Mg ha(-1) year(-1)), while stocks of larger-sized coarse DDW increased (0.02 Mg ha(-1) year(-1)). Stocks of total DDW C decreased (-0.14 Mg ha(-1) year(-1)), while standing dead and live tree stocks both increased, 0.01 and 0.44 Mg ha(-1) year(-1), respectively. The spatial distribution of DDW C stock change was highly heterogeneous with random forests model results indicating that management history, live tree stocking, natural disturbance, and growing degree days only partially explain stock change. Natural disturbances drove substantial C transfers from the live tree pool (≈-4 Mg ha(-1) year(-1)) to the standing dead tree pool (≈3 Mg ha(-1) year(-1)) with only a minimal increase in DDW C stocks (≈1 Mg ha(-1) year(-1)) in lower decay classes, suggesting a delayed transfer of C to the DDW pool. The assessment and management of DDW C flux is complicated by the diversity of natural and anthropogenic forces that drive their dynamics with the scale and timing of flux among forest C pools remaining a large knowledge gap.

Antibacterial activity of silver-killed bacteria: the "zombies" effect

NASA Astrophysics Data System (ADS)

Wakshlak, Racheli Ben-Knaz; Pedahzur, Rami; Avnir, David

2015-04-01

We report a previously unrecognized mechanism for the prolonged action of biocidal agents, which we denote as the zombies effect: biocidally-killed bacteria are capable of killing living bacteria. The concept is demonstrated by first killing Pseudomonas aeruginosa PAO1 with silver nitrate and then challenging, with the dead bacteria, a viable culture of the same bacterium: Efficient antibacterial activity of the killed bacteria is observed. A mechanism is suggested in terms of the action of the dead bacteria as a reservoir of silver, which, due to Le-Chatelier's principle, is re-targeted to the living bacteria. Langmuirian behavior, as well as deviations from it, support the proposed mechanism.

SU-E-T-458: Determining Threshold-Of-Failure for Dead Pixel Rows in EPID-Based Dosimetry

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

Gersh, J; Wiant, D

Purpose: A pixel correction map is applied to all EPID-based applications on the TrueBeam (Varian Medical Systems, Palo Alto, CA). When dead pixels are detected, an interpolative smoothing algorithm is applied using neighboring-pixel information to supplement missing-pixel information. The vendor suggests that when the number of dead pixels exceeds 70,000, the panel should be replaced. It is common for entire detector rows to be dead, as well as their neighboring rows. Approximately 70 rows can be dead before the panel reaches this threshold. This study determines the number of neighboring dead-pixel rows that would create a large enough deviation inmore » measured fluence to cause failures in portal dosimetry (PD). Methods: Four clinical two-arc VMAT plans were generated using Eclipse's AXB algorithm and PD plans were created using the PDIP algorithm. These plans were chosen to represent those commonly encountered in the clinic: prostate, lung, abdomen, and neck treatments. During each iteration of this study, an increasing number of dead-pixel rows are artificially applied to the correction map and a fluence QA is performed using the EPID (corrected with this map). To provide a worst-case-scenario, the dead-pixel rows are chosen so that they present artifacts in the highfluence region of the field. Results: For all eight arc-fields deemed acceptable via a 3%/3mm gamma analysis (pass rate greater than 99%), VMAT QA yielded identical results with a 5 pixel-width dead zone. When 10 dead lines were present, half of the fields had pass rates below the 99% pass rate. With increasing dead rows, the pass rates were reduced substantially. Conclusion: While the vendor still suggests to request service at the point where 70,000 dead rows are measured (as recommended by the vendor), the authors suggest that service should be requested when there are greater than 5 consecutive dead rows.« less

International Conference on Deformation, Yield and Fracture of Polymers (9th) Held in Cambridge, UK on 11-14 April, 1994. Conference Papers

DTIC Science & Technology

1994-01-01

microplasticity and relaxations in polymers using a laser interferometer NN Peschanskaya, PN Yakushev, AB Sinani and VA Bershtein (Ioffe Physical-Technical...Medicine, London, UK) P29 Toughening mechanism of flame-retarded plastics L Utevskii, I Finberg, E Reznik and M Muskatel (Dead Sea Bromine group, Beer...Dead Sea Bromine Group, Beer Sheva, Israel) P31 Stress-relaxation due to environmental effects on polypropylene and fiber reinforced polyester E Gutman

Aerobic Biodegradation of DI-n-Butylphthalate by Pure and Mixed Bacterial Species

DTIC Science & Technology

1996-05-01

70 days in their studies. Wang and Grady (1995)7 explored the effects of biosorption and dissolution on the biodegradation of DBP. Biosorption ...isotherms for DBP by live and dead bacteria was evaluated by Wang and Grady (1994)4. Biosorption was significant in both live and dead bacteria, however, it...Data on Organic Chemicals. 2nd Ed., Van Nostrand Reinhold Company, New York. 4. Wang, X. and Grady Jr., C. P. L. (1994) Comparison of Biosorption

Raising the Dead without a Red Sea-Dead Sea Canal? A hydro-economic-institutional analysis

NASA Astrophysics Data System (ADS)

Rosenberg, D. E.

2010-12-01

Presently, just 100 million cubic meters per year (MCM/year) of the 1,000+ MCM/year that historically flowed in the lower Jordan River reach the Dead Sea. Israeli, Jordanian, and Syrian dam and extraction projects built over seven decades have principally caused the reduced flow, associated falling Dead Sea level, shrinking surface area, sink holes, salinity, and other catastrophic problems. These problems will be magnified in the face of up to 20% reductions in precipitation expected with climate change. The fix proposed by Jordan, Israel, and Palestine—and now under study by the World Bank—envisions building a $US 5 billion multipurpose canal from the Red Sea to the Dead Sea that would also generate hydropower and desalinated water. Yet alternatives to raise the Dead Sea level that could take advantage of hydrologic variability remain unstudied. Here we show system-wide hydrologic and economic impacts of and discusses institutional management for alternatives to raise the Dead Sea level. Hydro-economic model results for the inter-tied Israel-Jordan-Palestinian water systems show the desalination component of the Red Sea-Dead Sea project is economically unviable. Further, many decentralized new supply, wastewater reuse, conveyance, conservation, and leak reduction projects and programs in each country together increase economic benefits and can reliably deliver up to 900 MCM/year to the Dead Sea. In all cases, results show that net benefits fall and water scarcity rises as the flow volume delivered to the Dead Sea increases. These findings suggest that (i) each country has little individual incentive to allow water to flow to the Dead Sea, and (ii) outside institutions—such as the World Bank—that seek to raise the Dead should instead offer the countries direct incentives to deliver water rather than build them new infrastructure. The work expands the set of viable options to raise the Dead Sea level and can help the World Bank and others recommend whether to move forward with the Red Sea-Dead Sea project.

Mitigating by-catch of diamondback terrapins in crab pots

USGS Publications Warehouse

Hart, Kristen M.; Crowder, Larry B.

2011-01-01

Chronic by-catch of diamondback terrapins (Malaclemys terrapin) in blue crab (Callinectes sapidus) pots is a concern for terrapin conservation along the United States Atlantic and Gulf of Mexico coasts. Despite the availability of by-catch reduction devices (BRDs) for crab pots, adoption of BRDs has not been mandated and by-catch of terrapins continues. We conducted experimental fishing studies in North Carolina's year-round blue crab fishery from 2000 to 2004 to evaluate the ability of various BRDs to reduce terrapin by-catch without a concomitant reduction in the catch of blue crabs. In 4,822 crab pot days fished, we recorded only 21 terrapin captures. Estimated capture rates were 0.003 terrapins/pot per day in hard crab experimental fishing and 0.008 terrapins/pot per day in peeler experimental fishing. All terrapin captures occurred from April to mid-May within 321.4 m of the shoreline. Longer soak times produced more dead terrapins, with 4 live and 4 dead during hard crab experimental fishing and 11 live and 2 dead during peeler experimental fishing. The 4.0-cm BRDs in fall and 4.5-cm and 5.0-cm BRDs in spring reduced the catch of legal-sized male hard crabs by 26.6%, 21.2%, and 5.7%, respectively. Only the 5.0-cm BRDs did not significantly affect the catch of legal-sized hard male crabs. However, BRDs had no measurable effect on catch of target crabs in the peeler crab fishery. Our results identify 3 complementary and economically feasible tools for blue crab fishery managers to exclude terrapins from commercially fished crab pots in North Carolina: 1) gear modifications (e.g., BRDs); 2) distance-to-shore restrictions; and 3) time-of-year regulations. These measures combined could provide a reduction in terrapin by-catch of up to 95% without a significant reduction in target crab catch.

Capnographic Parameters in Ventilated Patients: Correspondence with Airway and Lung Tissue Mechanics.

PubMed

Csorba, Zsofia; Petak, Ferenc; Nevery, Kitti; Tolnai, Jozsef; Balogh, Adam L; Rarosi, Ferenc; Fodor, Gergely H; Babik, Barna

2016-05-01

Although the mechanical status of the lungs affects the shape of the capnogram, the relations between the capnographic parameters and those reflecting the airway and lung tissue mechanics have not been established in mechanically ventilated patients. We, therefore, set out to characterize how the mechanical properties of the airways and lung tissues modify the indices obtained from the different phases of the time and volumetric capnograms and how the lung mechanical changes are reflected in the altered capnographic parameters after a cardiopulmonary bypass (CPB). Anesthetized, mechanically ventilated patients (n = 101) undergoing heart surgery were studied in a prospective consecutive cross-sectional study under the open-chest condition before and 5 minutes after CPB. Forced oscillation technique was applied to measure airway resistance (Raw), tissue damping (G), and elastance (H). Time and volumetric capnography were performed to assess parameters reflecting the phase II (SII) and phase III slopes (SIII), their transition (D2min), the dead-space indices according to Fowler, Bohr, and Enghoff and the intrapulmonary shunt. Before CPB, SII and D2min exhibited the closest (P = 0.006) associations with H (0.65 and -0.57; P < 0.0001, respectively), whereas SIII correlated most strongly (P < 0.0001) with Raw (r = 0.63; P < 0.0001). CPB induced significant elevations in Raw and G and H (P < 0.0001). These adverse mechanical changes were reflected consistently in SII, SIII, and D2min, with weaker correlations with the dead-space indices (P < 0.0001). The intrapulmonary shunt expressed as the difference between the Enghoff and Bohr dead-space parameters was increased after CPB (95% ± 5% [SEM] vs 143% ± 6%; P < 0.001). In mechanically ventilated patients, the capnographic parameters from the early phase of expiration (SII and D2min) are linked to the pulmonary elastic recoil, whereas the effect of airway patency on SIII dominates over the lung tissue stiffness. However, severe deterioration in lung resistance or elastance affects both capnogram slopes.

40 CFR 92.203 - Application for certification.

Code of Federal Regulations, 2010 CFR

2010-07-01

...., degrees before or after top-dead-center), and any functional dependence of such timing on other... physically adjustable range; and (v) Information relating to why the physical limits or stops used to...

Brain Death and Human Organismal Integration: A Symposium on the Definition of Death

PubMed Central

Moschella, Melissa

2016-01-01

Does the ability of some brain dead bodies to maintain homeostasis with the help of artificial life support actually imply that those bodies are living human organisms? Or might it be possible that a brain dead body on life support is a mere collection of still-living cells, organs and tissues which can coordinate with one another, but which lack the genuine integration that is the hallmark of a unified human organism as a whole? To foster further study of these difficult and timely questions, a Symposium on the Definition of Death was held at The Catholic University of America in June 2014. The Symposium brought together scholars from a variety of disciplines—law, medicine, biology, philosophy and theology—who all share a commitment to the dead donor rule and to a biological definition of death, but who have differing opinions regarding the validity of neurological criteria for human death. The papers found in this special issue are among the fruits of this Symposium. PMID:27107428

Scale-free distribution of Dead Sea sinkholes: Observations and modeling

NASA Astrophysics Data System (ADS)

Yizhaq, H.; Ish-Shalom, C.; Raz, E.; Ashkenazy, Y.

2017-05-01

There are currently more than 5500 sinkholes along the Dead Sea in Israel. These were formed due to the dissolution of subsurface salt layers as a result of the replacement of hypersaline groundwater by fresh brackish groundwater. This process has been associated with a sharp decline in the Dead Sea water level, currently more than 1 m/yr, resulting in a lower water table that has allowed the intrusion of fresher brackish water. We studied the distribution of the sinkhole sizes and found that it is scale free with a power law exponent close to 2. We constructed a stochastic cellular automata model to understand the observed scale-free behavior and the growth of the sinkhole area in time. The model consists of a lower salt layer and an upper soil layer in which cavities that develop in the lower layer lead to collapses in the upper layer. The model reproduces the observed power law distribution without involving the threshold behavior commonly associated with criticality.

Two and a Half Hours of Cardiopulmonary Resuscitation in a Deceased Brain Dead Donor before Liver Transplantation - A Good Idea to Accept?

PubMed

Hoyer, Dieter P; Kaiser, Gernot M; Paul, Andreas; Machairas, Nikolaos; Molmenti, Ernesto P; Sotiropoulos, Georgios C

2017-01-01

The sequelae of cardiac arrest (CA) and cardiopulmonary resuscitation (CPR) in organ donors potentially results in ischemic organ injury and graft dysfunction after transplantation. Thresholds of resuscitation times in brain dead liver donors have not been established so far. We report the case of a brain dead liver donor who experienced 2.5 hours of CPR whose liver was successfully transplanted. A 75-year-old male experienced CA and was treated by CPR with streptokinase application for 2.5 hours until stabilization of cardiac function. Brain death was diagnosed at the day of admission and organ donation carried out within 24 hours. The DRI was 2.2 with a CIT of 8.8 hours. The liver was transplanted into a 64-year-old recipient suffering from alcoholic liver cirrhosis and a MELD-score of 10 non representative for severity of disease. During follow up of 4 years ERCP and stenting was performed regularly for biliary anastomosis stenosis. The patient remained in a very good overall state of health without any signs of liver dysfunction. This case demonstrates that an extensive period of CPR is not an obligatory exclusion criterion for liver donation. Thresholds of CPR times as well as predictive factors in donors with CA should be established. Celsius.

Possible connection between large volcanic eruptions and level rise episodes in the Dead Sea Basin

NASA Astrophysics Data System (ADS)

Bookman, R.; Filin, S.; Avni, Y.; Rosenfeld, D.; Marco, S.

2014-12-01

The June 1991 Pinatubo volcanic eruption perturbed the atmosphere, triggering short-term worldwide changes in climate. The following winter was anomalously wet in the Levant, with a ~2-meter increase in the Dead Sea level that created a morphological terrace along the lake's shore. Given the global effects of volcanogenic aerosols, we tested the hypothesis that the 1991-92 shore terrace is a modern analogue to the linkage between past volcanic eruptions and a sequence of shore terraces in the Dead Sea Basin. Analysis of precipitation series from Jerusalem showed a significant positive correlation between the Dust Veil Index (DVI) of the modern eruptions and annual rainfall. The DVI was found to explain nearly 50% of the variability in the annual rainfall, such that greater DVI means more rainfall. Other factors that may affect the annual rainfall in the region as the Southern Oscillation Index (SOI) and the North Atlantic oscillations (NAO) were incorporated along with the DVI in a linear multiple regression model. It was found that the NAO did not contribute anything except for increased noise, but the added SOI increased the explained variability of rainfall to more than 60%. Volcanic eruptions with a VEI of 6, as in the Pinatubo, occurred about once a century during the Holocene and the last glacial-interglacial cycle. This occurrence is similar to the frequency of shore terrace build-up during the Lake Lisan desiccation. Sixteen shore terraces, detected using airborne laser scanning data, were interpreted as indicating short-term level rises due to episodes of enhanced precipitation and runoff during the dramatic drop in Lake Lisan's (palaeo-Dead Sea) level at the end of the LGM. The terraces were compared with a time series of volcanogenic sulfate from the GISP2 record, and similar numbers of sulfate concentration peaks and terraces were found. Furthermore, a significant correlation was found between SO4 concentration peaks and the terraces heights. This correlation may indicate a link between the explosivity, magnitude of stratospheric injection, and the impact on the northern hemisphere water balance. The record of such short-term climato-hydrological effects is made possible by the dramatic desiccation of Lake Lisan. Detailed records of such events provide a demonstration of global climatic teleconnections.