Sample records for accumulating evidence points

  1. Evidence Accumulator or Decision Threshold – Which Cortical Mechanism are We Observing?

    PubMed Central

    Simen, Patrick

    2012-01-01

    Most psychological models of perceptual decision making are of the accumulation-to-threshold variety. The neural basis of accumulation in parietal and prefrontal cortex is therefore a topic of great interest in neuroscience. In contrast, threshold mechanisms have received less attention, and their neural basis has usually been sought in subcortical structures. Here I analyze a model of a decision threshold that can be implemented in the same cortical areas as evidence accumulators, and whose behavior bears on two open questions in decision neuroscience: (1) When ramping activity is observed in a brain region during decision making, does it reflect evidence accumulation? (2) Are changes in speed-accuracy tradeoffs and response biases more likely to be achieved by changes in thresholds, or in accumulation rates and starting points? The analysis suggests that task-modulated ramping activity, by itself, is weak evidence that a brain area mediates evidence accumulation as opposed to threshold readout; and that signs of modulated accumulation are as likely to indicate threshold adaptation as adaptation of starting points and accumulation rates. These conclusions imply that how thresholds are modeled can dramatically impact accumulator-based interpretations of this data. PMID:22737136

  2. An evidence accumulation model for conflict detection performance in a simulated air traffic control task.

    PubMed

    Neal, Andrew; Kwantes, Peter J

    2009-04-01

    The aim of this article is to develop a formal model of conflict detection performance. Our model assumes that participants iteratively sample evidence regarding the state of the world and accumulate it over time. A decision is made when the evidence reaches a threshold that changes over time in response to the increasing urgency of the task. Two experiments were conducted to examine the effects of conflict geometry and timing on response proportions and response time. The model is able to predict the observed pattern of response times, including a nonmonotonic relationship between distance at point of closest approach and response time, as well as effects of angle of approach and relative velocity. The results demonstrate that evidence accumulation models provide a good account of performance on a conflict detection task. Evidence accumulation models are a form of dynamic signal detection theory, allowing for the analysis of response times as well as response proportions, and can be used for simulating human performance on dynamic decision tasks.

  3. Apparatus and method for creating a photonic densely-accumulated ray-point

    NASA Technical Reports Server (NTRS)

    Park, Yeonjoon (Inventor); Choi, Sang H. (Inventor); King, Glen C. (Inventor); Elliott, James R. (Inventor)

    2012-01-01

    An optical apparatus includes an optical diffraction device configured for diffracting a predetermined wavelength of incident light onto adjacent optical focal points, and a photon detector for detecting a spectral characteristic of the predetermined wavelength. One of the optical focal points is a constructive interference point and the other optical focal point is a destructive interference point. The diffraction device, which may be a micro-zone plate (MZP) of micro-ring gratings or an optical lens, generates a constructive ray point using phase-contrasting of the destructive interference point. The ray point is located between adjacent optical focal points. A method of generating a densely-accumulated ray point includes directing incident light onto the optical diffraction device, diffracting the selected wavelength onto the constructive interference focal point and the destructive interference focal point, and generating the densely-accumulated ray point in a narrow region.

  4. What is value—accumulated reward or evidence?

    PubMed Central

    Friston, Karl; Adams, Rick; Montague, Read

    2012-01-01

    Why are you reading this abstract? In some sense, your answer will cast the exercise as valuable—but what is value? In what follows, we suggest that value is evidence or, more exactly, log Bayesian evidence. This implies that a sufficient explanation for valuable behavior is the accumulation of evidence for internal models of our world. This contrasts with normative models of optimal control and reinforcement learning, which assume the existence of a value function that explains behavior, where (somewhat tautologically) behavior maximizes value. In this paper, we consider an alternative formulation—active inference—that replaces policies in normative models with prior beliefs about the (future) states agents should occupy. This enables optimal behavior to be cast purely in terms of inference: where agents sample their sensorium to maximize the evidence for their generative model of hidden states in the world, and minimize their uncertainty about those states. Crucially, this formulation resolves the tautology inherent in normative models and allows one to consider how prior beliefs are themselves optimized in a hierarchical setting. We illustrate these points by showing that any optimal policy can be specified with prior beliefs in the context of Bayesian inference. We then show how these prior beliefs are themselves prescribed by an imperative to minimize uncertainty. This formulation explains the saccadic eye movements required to read this text and defines the value of the visual sensations you are soliciting. PMID:23133414

  5. Discriminating evidence accumulation from urgency signals in speeded decision making.

    PubMed

    Hawkins, Guy E; Wagenmakers, Eric-Jan; Ratcliff, Roger; Brown, Scott D

    2015-07-01

    The dominant theoretical paradigm in explaining decision making throughout both neuroscience and cognitive science is known as “evidence accumulation”--The core idea being that decisions are reached by a gradual accumulation of noisy information. Although this notion has been supported by hundreds of experiments over decades of study, a recent theory proposes that the fundamental assumption of evidence accumulation requires revision. The "urgency gating" model assumes decisions are made without accumulating evidence, using only moment-by-moment information. Under this assumption, the successful history of evidence accumulation models is explained by asserting that the two models are mathematically identical in standard experimental procedures. We demonstrate that this proof of equivalence is incorrect, and that the models are not identical, even when both models are augmented with realistic extra assumptions. We also demonstrate that the two models can be perfectly distinguished in realistic simulated experimental designs, and in two real data sets; the evidence accumulation model provided the best account for one data set, and the urgency gating model for the other. A positive outcome is that the opposing modeling approaches can be fruitfully investigated without wholesale change to the standard experimental paradigms. We conclude that future research must establish whether the urgency gating model enjoys the same empirical support in the standard experimental paradigms that evidence accumulation models have gathered over decades of study. Copyright © 2015 the American Physiological Society.

  6. Evidence accumulation as a model for lexical selection.

    PubMed

    Anders, R; Riès, S; van Maanen, L; Alario, F X

    2015-11-01

    We propose and demonstrate evidence accumulation as a plausible theoretical and/or empirical model for the lexical selection process of lexical retrieval. A number of current psycholinguistic theories consider lexical selection as a process related to selecting a lexical target from a number of alternatives, which each have varying activations (or signal supports), that are largely resultant of an initial stimulus recognition. We thoroughly present a case for how such a process may be theoretically explained by the evidence accumulation paradigm, and we demonstrate how this paradigm can be directly related or combined with conventional psycholinguistic theory and their simulatory instantiations (generally, neural network models). Then with a demonstrative application on a large new real data set, we establish how the empirical evidence accumulation approach is able to provide parameter results that are informative to leading psycholinguistic theory, and that motivate future theoretical development. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Evidence accumulation detected in BOLD signal using slow perceptual decision making.

    PubMed

    Krueger, Paul M; van Vugt, Marieke K; Simen, Patrick; Nystrom, Leigh; Holmes, Philip; Cohen, Jonathan D

    2017-04-01

    We assessed whether evidence accumulation could be observed in the BOLD signal during perceptual decision making. This presents a challenge since the hemodynamic response is slow, while perceptual decisions are typically fast. Guided by theoretical predictions of the drift diffusion model, we slowed down decisions by penalizing participants for incorrect responses. Second, we distinguished BOLD activity related to stimulus detection (modeled using a boxcar) from activity related to integration (modeled using a ramp) by minimizing the collinearity of GLM regressors. This was achieved by dissecting a boxcar into its two most orthogonal components: an "up-ramp" and a "down-ramp." Third, we used a control condition in which stimuli and responses were similar to the experimental condition, but that did not engage evidence accumulation of the stimuli. The results revealed an absence of areas in parietal cortex that have been proposed to drive perceptual decision making but have recently come into question; and newly identified regions that are candidates for involvement in evidence accumulation. Previous fMRI studies have either used fast perceptual decision making, which precludes the measurement of evidence accumulation, or slowed down responses by gradually revealing stimuli. The latter approach confounds perceptual detection with evidence accumulation because accumulation is constrained by perceptual input. We slowed down the decision making process itself while leaving perceptual information intact. This provided a more sensitive and selective observation of brain regions associated with the evidence accumulation processes underlying perceptual decision making than previous methods. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Normative evidence accumulation in unpredictable environments

    PubMed Central

    Glaze, Christopher M; Kable, Joseph W; Gold, Joshua I

    2015-01-01

    In our dynamic world, decisions about noisy stimuli can require temporal accumulation of evidence to identify steady signals, differentiation to detect unpredictable changes in those signals, or both. Normative models can account for learning in these environments but have not yet been applied to faster decision processes. We present a novel, normative formulation of adaptive learning models that forms decisions by acting as a leaky accumulator with non-absorbing bounds. These dynamics, derived for both discrete and continuous cases, depend on the expected rate of change of the statistics of the evidence and balance signal identification and change detection. We found that, for two different tasks, human subjects learned these expectations, albeit imperfectly, then used them to make decisions in accordance with the normative model. The results represent a unified, empirically supported account of decision-making in unpredictable environments that provides new insights into the expectation-driven dynamics of the underlying neural signals. DOI: http://dx.doi.org/10.7554/eLife.08825.001 PMID:26322383

  9. Conscious and Nonconscious Processes:Distinct Forms of Evidence Accumulation?

    NASA Astrophysics Data System (ADS)

    Dehaene, Stanislas

    Among the many brain events evoked by a visual stimulus, which ones are associated specifically with conscious perception, and which merely reflect nonconscious processing? Understanding the neuronal mechanisms of consciousness is a major challenge for cognitive neuroscience. Recently, progress has been achieved by contrasting behavior and brain activation in minimally different experimental conditions, one of which leads to conscious perception whereas the other does not. This chapter reviews briefly this line of research and speculates on its theoretical interpretation. I propose to draw links between evidence accumulation models, which are highly successful in capturing elementary psychophysical decisions, and the conscious/nonconscious dichotomy. In this framework, conscious access would correspond to the crossing of a threshold in evidence accumulation within a distributed global workspace, a set of recurrently connected neurons with long axons that is able to integrate and broadcast back evidence from multiple brain processors. During nonconscious processing, evidence would be accumulated locally within specialized subcircuits, but would fail to reach the threshold needed for global ignition and, therefore, conscious reportability.

  10. Accumulation of evidence during sequential decision making: the importance of top-down factors.

    PubMed

    de Lange, Floris P; Jensen, Ole; Dehaene, Stanislas

    2010-01-13

    In the last decade, great progress has been made in characterizing the accumulation of neural information during simple unitary perceptual decisions. However, much less is known about how sequentially presented evidence is integrated over time for successful decision making. The aim of this study was to study the mechanisms of sequential decision making in humans. In a magnetoencephalography (MEG) study, we presented healthy volunteers with sequences of centrally presented arrows. Sequence length varied between one and five arrows, and the accumulated directions of the arrows informed the subject about which hand to use for a button press at the end of the sequence (e.g., LRLRR should result in a right-hand press). Mathematical modeling suggested that nonlinear accumulation was the rational strategy for performing this task in the presence of no or little noise, whereas quasilinear accumulation was optimal in the presence of substantial noise. MEG recordings showed a correlate of evidence integration over parietal and central cortex that was inversely related to the amount of accumulated evidence (i.e., when more evidence was accumulated, neural activity for new stimuli was attenuated). This modulation of activity likely reflects a top-down influence on sensory processing, effectively constraining the influence of sensory information on the decision variable over time. The results indicate that, when making decisions on the basis of sequential information, the human nervous system integrates evidence in a nonlinear manner, using the amount of previously accumulated information to constrain the accumulation of additional evidence.

  11. Evidence Accumulation and Choice Maintenance Are Dissociated in Human Perceptual Decision Making

    PubMed Central

    Pedersen, Mads Lund; Endestad, Tor; Biele, Guido

    2015-01-01

    Perceptual decision making in monkeys relies on decision neurons, which accumulate evidence and maintain choices until a response is given. In humans, several brain regions have been proposed to accumulate evidence, but it is unknown if these regions also maintain choices. To test if accumulator regions in humans also maintain decisions we compared delayed and self-paced responses during a face/house discrimination decision making task. Computational modeling and fMRI results revealed dissociated processes of evidence accumulation and decision maintenance, with potential accumulator activations found in the dorsomedial prefrontal cortex, right inferior frontal gyrus and bilateral insula. Potential maintenance activation spanned the frontal pole, temporal gyri, precuneus and the lateral occipital and frontal orbital cortices. Results of a quantitative reverse inference meta-analysis performed to differentiate the functions associated with the identified regions did not narrow down potential accumulation regions, but suggested that response-maintenance might rely on a verbalization of the response. PMID:26510176

  12. Active inference, evidence accumulation and the urn task

    PubMed Central

    FitzGerald, Thomas HB; Schwartenbeck, Philipp; Moutoussis, Michael; Dolan, Raymond J; Friston, Karl

    2015-01-01

    Deciding how much evidence to accumulate before making a decision is a problem we and other animals often face, but one which is not completely understood. This issue is particularly important because a tendency to sample less information (often known as reflection impulsivity) is a feature in several psychopathologies, such as psychosis. A formal understanding information sampling may therefore clarify the computational anatomy of psychopathology. In this theoretical paper, we consider evidence accumulation in terms of active (Bayesian) inference using a generic model of Markov decision processes. Here, agents are equipped with beliefs about their own behaviour – in this case, that they will make informed decisions. Normative decision-making is then modelled using variational Bayes to minimise surprise about choice outcomes. Under this scheme, different facets of belief updating map naturally onto the functional anatomy of the brain (at least at a heuristic level). Of particular interest is the key role played by the expected precision of beliefs about control, which we have previously suggested may be encoded by dopaminergic neurons in the midbrain. We show that manipulating expected precision strongly affects how much information an agent characteristically samples, and thus provides a possible link between impulsivity and dopaminergic dysfunction. Our study therefore represents a step towards understanding evidence accumulation in terms of neurobiologically plausible Bayesian inference, and may cast light on why this process is disordered in psychopathology. PMID:25514108

  13. Content-specific evidence accumulation in inferior temporal cortex during perceptual decision-making

    PubMed Central

    Tremel, Joshua J.; Wheeler, Mark E.

    2015-01-01

    During a perceptual decision, neuronal activity can change as a function of time-integrated evidence. Such neurons may serve as decision variables, signaling a choice when activity reaches a boundary. Because the signals occur on a millisecond timescale, translating to human decision-making using functional neuroimaging has been challenging. Previous neuroimaging work in humans has identified patterns of neural activity consistent with an accumulation account. However, the degree to which the accumulating neuroimaging signals reflect specific sources of perceptual evidence is unknown. Using an extended face/house discrimination task in conjunction with cognitive modeling, we tested whether accumulation signals, as measured using functional magnetic resonance imaging (fMRI), are stimulus-specific. Accumulation signals were defined as a change in the slope of the rising edge of activation corresponding with response time (RT), with higher slopes associated with faster RTs. Consistent with an accumulation account, fMRI activity in face- and house-selective regions in the inferior temporal cortex increased at a rate proportional to decision time in favor of the preferred stimulus. This finding indicates that stimulus-specific regions perform an evidence integrative function during goal-directed behavior and that different sources of evidence accumulate separately. We also assessed the decision-related function of other regions throughout the brain and found that several regions were consistent with classifications from prior work, suggesting a degree of domain generality in decision processing. Taken together, these results provide support for an integration-to-boundary decision mechanism and highlight possible roles of both domain-specific and domain-general regions in decision evidence evaluation. PMID:25562821

  14. Evidence Accumulation and Change Rate Inference in Dynamic Environments.

    PubMed

    Radillo, Adrian E; Veliz-Cuba, Alan; Josić, Krešimir; Kilpatrick, Zachary P

    2017-06-01

    In a constantly changing world, animals must account for environmental volatility when making decisions. To appropriately discount older, irrelevant information, they need to learn the rate at which the environment changes. We develop an ideal observer model capable of inferring the present state of the environment along with its rate of change. Key to this computation is an update of the posterior probability of all possible change point counts. This computation can be challenging, as the number of possibilities grows rapidly with time. However, we show how the computations can be simplified in the continuum limit by a moment closure approximation. The resulting low-dimensional system can be used to infer the environmental state and change rate with accuracy comparable to the ideal observer. The approximate computations can be performed by a neural network model via a rate-correlation-based plasticity rule. We thus show how optimal observers accumulate evidence in changing environments and map this computation to reduced models that perform inference using plausible neural mechanisms.

  15. A quantitative study on accumulation of age mass around stagnation points in nested flow systems

    NASA Astrophysics Data System (ADS)

    Jiang, Xiao-Wei; Wan, Li; Ge, Shemin; Cao, Guo-Liang; Hou, Guang-Cai; Hu, Fu-Sheng; Wang, Xu-Sheng; Li, Hailong; Liang, Si-Hai

    2012-12-01

    The stagnant zones in nested flow systems have been assumed to be critical to accumulation of transported matter, such as metallic ions and hydrocarbons in drainage basins. However, little quantitative research has been devoted to prove this assumption. In this paper, the transport of age mass is used as an example to demonstrate that transported matter could accumulate around stagnation points. The spatial distribution of model age is analyzed in a series of drainage basins of different depths. We found that groundwater age has a local or regional maximum value around each stagnation point, which proves the accumulation of age mass. In basins where local, intermediate and regional flow systems are all well developed, the regional maximum groundwater age occurs at the regional stagnation point below the basin valley. This can be attributed to the long travel distances of regional flow systems as well as stagnancy of the water. However, when local flow systems dominate, the maximum groundwater age in the basin can be located around the local stagnation points due to stagnancy, which are far away from the basin valley. A case study is presented to illustrate groundwater flow and age in the Ordos Plateau, northwestern China. The accumulation of age mass around stagnation points is confirmed by tracer age determined by 14C dating in two boreholes and simulated age near local stagnation points under different dispersivities. The results will help shed light on the relationship between groundwater flow and distributions of groundwater age, hydrochemistry, mineral resources, and hydrocarbons in drainage basins.

  16. Micro-Fresnel Zone Plate Optical Devices Using Densely Accumulated Ray Points

    NASA Technical Reports Server (NTRS)

    Choi, Sang H. (Inventor); Park, Yeonjoon (Inventor); King, Glen C. (Inventor); Elliott, James R. (Inventor)

    2011-01-01

    An embodiment generally relates to an optical device suitable for use with an optical medium for the storage and retrieval of data. The optical device includes an illumination means for providing a beam of optical radiation of wavelength .lamda. and an optical path that the beam of optical radiation follows. The optical device also includes a diffractive optical element defined by a plurality of annular sections. The plurality of annular sections having a first material alternately disposed with a plurality of annular sections comprising a second material. The diffractive optical element generates a plurality of focal points and densely accumulated ray points with phase contrast phenomena and the optical medium is positioned at a selected focal point or ray point of the diffractive optical element.

  17. Distinct effects of prefrontal and parietal cortex inactivations on an accumulation of evidence task in the rat

    PubMed Central

    Erlich, Jeffrey C; Brunton, Bingni W; Duan, Chunyu A; Hanks, Timothy D; Brody, Carlos D

    2015-01-01

    Numerous brain regions have been shown to have neural correlates of gradually accumulating evidence for decision-making, but the causal roles of these regions in decisions driven by accumulation of evidence have yet to be determined. Here, in rats performing an auditory evidence accumulation task, we inactivated the frontal orienting fields (FOF) and posterior parietal cortex (PPC), two rat cortical regions that have neural correlates of accumulating evidence and that have been proposed as central to decision-making. We used a detailed model of the decision process to analyze the effect of inactivations. Inactivation of the FOF induced substantial performance impairments that were quantitatively best described as an impairment in the output pathway of an evidence accumulator with a long integration time constant (>240 ms). In contrast, we found a minimal role for PPC in decisions guided by accumulating auditory evidence, even while finding a strong role for PPC in internally-guided decisions. DOI: http://dx.doi.org/10.7554/eLife.05457.001 PMID:25869470

  18. Perception as Evidence Accumulation and Bayesian Inference: Insights from Masked Priming

    ERIC Educational Resources Information Center

    Norris, Dennis; Kinoshita, Sachiko

    2008-01-01

    The authors argue that perception is Bayesian inference based on accumulation of noisy evidence and that, in masked priming, the perceptual system is tricked into treating the prime and the target as a single object. Of the 2 algorithms considered for formalizing how the evidence sampled from a prime and target is combined, only 1 was shown to be…

  19. Evidence accumulation in obsessive-compulsive disorder: the role of uncertainty and monetary reward on perceptual decision-making thresholds.

    PubMed

    Banca, Paula; Vestergaard, Martin D; Rankov, Vladan; Baek, Kwangyeol; Mitchell, Simon; Lapa, Tatyana; Castelo-Branco, Miguel; Voon, Valerie

    2015-03-13

    The compulsive behaviour underlying obsessive-compulsive disorder (OCD) may be related to abnormalities in decision-making. The inability to commit to ultimate decisions, for example, patients unable to decide whether their hands are sufficiently clean, may reflect failures in accumulating sufficient evidence before a decision. Here we investigate the process of evidence accumulation in OCD in perceptual discrimination, hypothesizing enhanced evidence accumulation relative to healthy volunteers. Twenty-eight OCD patients and thirty-five controls were tested with a low-level visual perceptual task (random-dot-motion task, RDMT) and two response conflict control tasks. Regression analysis across different motion coherence levels and Hierarchical Drift Diffusion Modelling (HDDM) were used to characterize response strategies between groups in the RDMT. Patients required more evidence under high uncertainty perceptual contexts, as indexed by longer response time and higher decision boundaries. HDDM, which defines a decision when accumulated noisy evidence reaches a decision boundary, further showed slower drift rate towards the decision boundary reflecting poorer quality of evidence entering the decision process in patients under low uncertainty. With monetary incentives emphasizing speed and penalty for slower responses, patients decreased the decision thresholds relative to controls, accumulating less evidence in low uncertainty. These findings were unrelated to visual perceptual deficits and response conflict. This study provides evidence for impaired decision-formation processes in OCD, with a differential influence of high and low uncertainty contexts on evidence accumulation (decision threshold) and on the quality of evidence gathered (drift rates). It further emphasizes that OCD patients are sensitive to monetary incentives heightening speed in the speed-accuracy tradeoff, improving evidence accumulation.

  20. Sequential biases in accumulating evidence

    PubMed Central

    Huggins, Richard; Dogo, Samson Henry

    2015-01-01

    Whilst it is common in clinical trials to use the results of tests at one phase to decide whether to continue to the next phase and to subsequently design the next phase, we show that this can lead to biased results in evidence synthesis. Two new kinds of bias associated with accumulating evidence, termed ‘sequential decision bias’ and ‘sequential design bias’, are identified. Both kinds of bias are the result of making decisions on the usefulness of a new study, or its design, based on the previous studies. Sequential decision bias is determined by the correlation between the value of the current estimated effect and the probability of conducting an additional study. Sequential design bias arises from using the estimated value instead of the clinically relevant value of an effect in sample size calculations. We considered both the fixed‐effect and the random‐effects models of meta‐analysis and demonstrated analytically and by simulations that in both settings the problems due to sequential biases are apparent. According to our simulations, the sequential biases increase with increased heterogeneity. Minimisation of sequential biases arises as a new and important research area necessary for successful evidence‐based approaches to the development of science. © 2015 The Authors. Research Synthesis Methods Published by John Wiley & Sons Ltd. PMID:26626562

  1. Current algebras, measures quasi-invariant under diffeomorphism groups, and infinite quantum systems with accumulation points

    NASA Astrophysics Data System (ADS)

    Sakuraba, Takao

    The approach to quantum physics via current algebra and unitary representations of the diffeomorphism group is established. This thesis studies possible infinite Bose gas systems using this approach. Systems of locally finite configurations and systems of configurations with accumulation points are considered, with the main emphasis on the latter. In Chapter 2, canonical quantization, quantization via current algebra and unitary representations of the diffeomorphism group are reviewed. In Chapter 3, a new definition of the space of configurations is proposed and an axiom for general configuration spaces is abstracted. Various subsets of the configuration space, including those specifying the number of points in a Borel set and those specifying the number of accumulation points in a Borel set are proved to be measurable using this axiom. In Chapter 4, known results on the space of locally finite configurations and Poisson measure are reviewed in the light of the approach developed in Chapter 3, including the approach to current algebra in the Poisson space by Albeverio, Kondratiev, and Rockner. Goldin and Moschella considered unitary representations of the group of diffeomorphisms of the line based on self-similar random processes, which may describe infinite quantum gas systems with clusters. In Chapter 5, the Goldin-Moschella theory is developed further. Their construction of measures quasi-invariant under diffeomorphisms is reviewed, and a rigorous proof of their conjectures is given. It is proved that their measures with distinct correlation parameters are mutually singular. A quasi-invariant measure constructed by Ismagilov on the space of configurations with accumulation points on the circle is proved to be singular with respect to the Goldin-Moschella measures. Finally a generalization of the Goldin-Moschella measures to the higher-dimensional case is studied, where the notion of covariance matrix and the notion of condition number play important roles. A

  2. An Accumulation-of-Evidence Task Using Visual Pulses for Mice Navigating in Virtual Reality

    PubMed Central

    Pinto, Lucas; Koay, Sue A.; Engelhard, Ben; Yoon, Alice M.; Deverett, Ben; Thiberge, Stephan Y.; Witten, Ilana B.; Tank, David W.; Brody, Carlos D.

    2018-01-01

    The gradual accumulation of sensory evidence is a crucial component of perceptual decision making, but its neural mechanisms are still poorly understood. Given the wide availability of genetic and optical tools for mice, they can be useful model organisms for the study of these phenomena; however, behavioral tools are largely lacking. Here, we describe a new evidence-accumulation task for head-fixed mice navigating in a virtual reality (VR) environment. As they navigate down the stem of a virtual T-maze, they see brief pulses of visual evidence on either side, and retrieve a reward on the arm with the highest number of pulses. The pulses occur randomly with Poisson statistics, yielding a diverse yet well-controlled stimulus set, making the data conducive to a variety of computational approaches. A large number of mice of different genotypes were able to learn and consistently perform the task, at levels similar to rats in analogous tasks. They are sensitive to side differences of a single pulse, and their memory of the cues is stable over time. Moreover, using non-parametric as well as modeling approaches, we show that the mice indeed accumulate evidence: they use multiple pulses of evidence from throughout the cue region of the maze to make their decision, albeit with a small overweighting of earlier cues, and their performance is affected by the magnitude but not the duration of evidence. Additionally, analysis of the mice's running patterns revealed that trajectories are fairly stereotyped yet modulated by the amount of sensory evidence, suggesting that the navigational component of this task may provide a continuous readout correlated to the underlying cognitive variables. Our task, which can be readily integrated with state-of-the-art techniques, is thus a valuable tool to study the circuit mechanisms and dynamics underlying perceptual decision making, particularly under more complex behavioral contexts. PMID:29559900

  3. Dopamine Modulates the Efficiency of Sensory Evidence Accumulation During Perceptual Decision Making.

    PubMed

    Beste, Christian; Adelhöfer, Nico; Gohil, Krutika; Passow, Susanne; Roessner, Veit; Li, Shu-Chen

    2018-04-02

    Perceptual decision making is the process through which available sensory information is gathered and processed to guide our choices. However, the neuropsychopharmacological basis of this important cognitive function is largely elusive. Yet, theoretical considerations suggest that the dopaminergic system may play an important role. In a double-blind, randomized, placebo-controlled study design, we examined the effect of methylphenidate in 2 dosages (0.25 mg/kg and 0.5 mg/kg body weight) in separate groups of healthy young adults. We used a moving dots task in which the coherency of the direction of moving dots stimuli was manipulated in 3 levels (5%, 15%, and 35%). Drift diffusion modelling was applied to behavioral data to capture subprocesses of perceptual decision making. The findings show that only the drift rate (v), reflecting the efficiency of sensory evidence accumulation, but not the decision criterion threshold (a) or the duration of nondecisional processes (Ter), is affected by methylphenidate vs placebo administration. Compared with placebo, administering 0.25 mg/kg methylphenidate increased v, but only in the 35% coherence condition. Administering 0.5 mg/kg methylphenidate did not induce modulations. The data suggest that dopamine selectively modulates the efficacy of evidence accumulation during perceptual decision making. This modulation depends on 2 factors: (1) the degree to which the dopaminergic system is modulated using methylphenidate (i.e., methylphenidate dosage) and (2) the signal-to-noise ratio of the visual information. Dopamine affects sensory evidence accumulation only when dopamine concentration is not shifted beyond an optimal level and the incoming information is less noisy.

  4. Memory Accumulation Mechanisms in Human Cortex Are Independent of Motor Intentions

    PubMed Central

    Tosoni, Annalisa; Mignogna, Valeria; McAvoy, Mark P.; Shulman, Gordon L.; Corbetta, Maurizio; Romani, Gian Luca

    2014-01-01

    Previous studies on perceptual decision-making have often emphasized a tight link between decisions and motor intentions. Human decisions, however, also depend on memories or experiences that are not closely tied to specific motor responses. Recent neuroimaging findings have suggested that, during episodic retrieval, parietal activity reflects the accumulation of evidence for memory decisions. It is currently unknown, however, whether these evidence accumulation signals are functionally linked to signals for motor intentions coded in frontoparietal regions and whether activity in the putative memory accumulator tracks the amount of evidence for only previous experience, as reflected in “old” reports, or for both old and new decisions, as reflected in the accuracy of memory judgments. Here, human participants used saccadic-eye and hand-pointing movements to report recognition judgments on pictures defined by different degrees of evidence for old or new decisions. A set of cortical regions, including the middle intraparietal sulcus, showed a monotonic variation of the fMRI BOLD signal that scaled with perceived memory strength (older > newer), compatible with an asymmetrical memory accumulator. Another set, including the hippocampus and the angular gyrus, showed a nonmonotonic response profile tracking memory accuracy (higher > lower evidence), compatible with a symmetrical accumulator. In contrast, eye and hand effector-specific regions in frontoparietal cortex tracked motor intentions but were not modulated by the amount of evidence for the effector outcome. We conclude that item recognition decisions are supported by a combination of symmetrical and asymmetrical accumulation signals largely segregated from motor intentions. PMID:24828652

  5. Schrödinger Operator with Non-Zero Accumulation Points of Complex Eigenvalues

    NASA Astrophysics Data System (ADS)

    Bögli, Sabine

    2017-06-01

    We study Schrödinger operators {H=-Δ + V} in {L2(Ω)} where {Ω} is R^d or the half-space R+d, subject to (real) Robin boundary conditions in the latter case. For {p > d} we construct a non-real potential {V \\in Lp(Ω) \\cap L^{∞}(Ω)} that decays at infinity so that H has infinitely many non-real eigenvalues accumulating at every point of the essential spectrum {σ_ess(H)=[0,∞)}. This demonstrates that the Lieb-Thirring inequalities for selfadjoint Schrödinger operators are no longer true in the non-selfadjoint case.

  6. The nitrogen legacy: emerging evidence of nitrogen accumulation in anthropogenic landscapes

    NASA Astrophysics Data System (ADS)

    Van Meter, K. J.; Basu, N. B.; Veenstra, J. J.; Burras, C. L.

    2016-03-01

    Watershed and global-scale nitrogen (N) budgets indicate that the majority of the N surplus in anthropogenic landscapes does not reach the coastal oceans. While there is general consensus that this ‘missing’ N either exits the landscape via denitrification or is retained within watersheds as nitrate or organic N, the relative magnitudes of these pools and fluxes are subject to considerable uncertainty. Our study, for the first time, provides direct, large-scale evidence of N accumulation in the root zones of agricultural soils that may account for much of the ‘missing N’ identified in mass balance studies. We analyzed long-term soil data (1957-2010) from 2069 sites throughout the Mississippi River Basin (MRB) to reveal N accumulation in cropland of 25-70 kg ha-1 yr-1, a total of 3.8 ± 1.8 Mt yr-1 at the watershed scale. We then developed a simple modeling framework to capture N depletion and accumulation dynamics under intensive agriculture. Using the model, we show that the observed accumulation of soil organic N (SON) in the MRB over a 30 year period (142 Tg N) would lead to a biogeochemical lag time of 35 years for 99% of legacy SON, even with complete cessation of fertilizer application. By demonstrating that agricultural soils can act as a net N sink, the present work makes a critical contribution towards the closing of watershed N budgets.

  7. Evidence for gas accumulation associated with diapirism and gas hydrates at the head of the Cape Fear Slide

    USGS Publications Warehouse

    Schmuck, E.A.; Paull, C.K.

    1993-01-01

    Single-channel seismic reflection profiles show evidence for areas of significant gas accumulation at the head of the Cape Fear Slide on the continental rise oft North Carolina. Gas accumulation appears to occur beneath a gas hydrate seal in landward-dipping strata and in domed strata associated with diapirism. In addition, gas venting may have occurred near diapirs located at the head of the slide.

  8. A Review of Online Evidence-based Practice Point-of-Care Information Summary Providers

    PubMed Central

    Liberati, Alessandro; Moschetti, Ivan; Tagliabue, Ludovica; Moja, Lorenzo

    2010-01-01

    Background Busy clinicians need easy access to evidence-based information to inform their clinical practice. Publishers and organizations have designed specific tools to meet doctors’ needs at the point of care. Objective The aim of this study was to describe online point-of-care summaries and evaluate their breadth, content development, and editorial policy against their claims of being “evidence-based.” Methods We searched Medline, Google, librarian association websites, and information conference proceedings from January to December 2008. We included English Web-based point-of-care summaries designed to deliver predigested, rapidly accessible, comprehensive, periodically updated, evidence-based information to clinicians. Two investigators independently extracted data on the general characteristics and content presentation of summaries. We assessed and ranked point-of-care products according to: (1) coverage (volume) of medical conditions, (2) editorial quality, and (3) evidence-based methodology. We explored how these factors were associated. Results We retrieved 30 eligible summaries. Of these products, 18 met our inclusion criteria and were qualitatively described, and 16 provided sufficient data for quantitative evaluation. The median volume of medical conditions covered was 80.6% (interquartile range, 68.9% - 84.2%) and varied for the different products. Similarly, differences emerged for editorial policy (median 8.0, interquartile range 5.8 - 10.3) and evidence-based methodology scores (median 10.0, interquartile range 1.0 - 12.8) on a 15-point scale. None of these dimensions turned out to be significantly associated with the other dimensions (editorial quality and volume, Spearman rank correlation r = -0.001, P = .99; evidence-based methodology and volume, r = -0.19, P = .48; editorial and evidence-based methodology, r = 0.43, P =.09). Conclusions Publishers are moving to develop point-of-care summary products. Some of these have better profiles than

  9. Evidence for gas accumulation associated with diapirism and gas hydrates at the head of the Cape Fear Slide

    USGS Publications Warehouse

    Schmuck, E.A.; Paull, C.K.

    1993-01-01

    Single-channel seismic reflection profiles show evidence for areas of significant gas accumulation at the head of the Cape Fear Slide on the continental rise off North Carolina. Gas accumulation appears to occur beneath a gas hydrate seal in landward-dipping strata and in domed strata associated with diapirism. In addition, gas venting may have occurred near diapirs located at the head of the slide. ?? 1993 Springer-Verlag.

  10. Rapid temporal accumulation in spider fear: Evidence from hierarchical drift diffusion modelling.

    PubMed

    Tipples, Jason

    2015-12-01

    Fear can distort sense of time--making time seem slow or even stand still. Here, I used hierarchical drift diffusion modeling (HDDM; Vandekerckhove, Tuerlinckx, & Lee, 2008, 2011; Wiecki, Sofer, & Frank, 2013) to test the idea that temporal accumulation speeds up during fear. Eighteen high fearful and 23 low fearful participants judged the duration of both feared stimuli (spiders) and nonfeared stimuli (birds) in a temporal bisection task. The drift diffusion modeling results support the main hypothesis. In high but not low fearful individuals, evidence accumulated more rapidly toward a long duration decision-drift rates were higher-for spiders compared with birds. This result and further insights into how fear affects time perception would not have been possible on the basis of analyses of choice proportion data alone. Further results were interpreted in the context of a recent 2-stage model of time perception (Balcı & Simen, 2014). The results highlight the usefulness of diffusion modeling to test process-based explanations of disordered cognition in emotional disorders. (c) 2015 APA, all rights reserved).

  11. Chimpanzees can point to smaller amounts of food to accumulate larger amounts but they still fail the reverse-reward contingency task.

    PubMed

    Beran, Michael J; James, Brielle T; Whitham, Will; Parrish, Audrey E

    2016-10-01

    The reverse-reward contingency task presents 2 food sets to an animal, and they are required to choose the smaller of the 2 sets in order to receive the larger food set. Intriguingly, the majority of species tested on the reverse-reward task fail to learn this contingency in the absence of large trial counts, correction trials, and punishment techniques. The unique difficulty of this seemingly simple task likely reflects a failure of inhibitory control which is required to point toward a smaller and less desirable reward rather than a larger and more desirable reward. This failure by chimpanzees and other primates to pass the reverse-reward task is striking given the self-control they exhibit in a variety of other paradigms. For example, chimpanzees have consistently demonstrated a high capacity for delay of gratification in order to maximize accumulating food rewards in which foods are added item-by-item to a growing set until the subject consumes the rewards. To study the mechanisms underlying success in the accumulation task and failure in the reverse-reward task, we presented chimpanzees with several combinations of these 2 tasks to determine when chimpanzees might succeed in pointing to smaller food sets over larger food sets and how the nature of the task might determine the animals' success or failure. Across experiments, 3 chimpanzees repeatedly failed to solve the reverse-reward task, whereas they accumulated nearly all food items across all instances of the accumulation self-control task, even when they had to point to small amounts of food to accumulate larger amounts. These data indicate that constraints of these 2 related but still different tasks of behavioral inhibition are dependent upon the animals' perceptions of the choice set, their sense of control over the contents of choice sets, and the nature of the task constraints. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  12. Accumulator and random-walk models of psychophysical discrimination: a counter-evaluation.

    PubMed

    Vickers, D; Smith, P

    1985-01-01

    In a recent assessment of models of psychophysical discrimination, Heath criticises the accumulator model for its reliance on computer simulation and qualitative evidence, and contrasts it unfavourably with a modified random-walk model, which yields exact predictions, is susceptible to critical test, and is provided with simple parameter-estimation techniques. A counter-evaluation is presented, in which the approximations employed in the modified random-walk analysis are demonstrated to be seriously inaccurate, the resulting parameter estimates to be artefactually determined, and the proposed test not critical. It is pointed out that Heath's specific application of the model is not legitimate, his data treatment inappropriate, and his hypothesis concerning confidence inconsistent with experimental results. Evidence from adaptive performance changes is presented which shows that the necessary assumptions for quantitative analysis in terms of the modified random-walk model are not satisfied, and that the model can be reconciled with data at the qualitative level only by making it virtually indistinguishable from an accumulator process. A procedure for deriving exact predictions for an accumulator process is outlined.

  13. RELATING ACCUMULATOR MODEL PARAMETERS AND NEURAL DYNAMICS

    PubMed Central

    Purcell, Braden A.; Palmeri, Thomas J.

    2016-01-01

    Accumulator models explain decision-making as an accumulation of evidence to a response threshold. Specific model parameters are associated with specific model mechanisms, such as the time when accumulation begins, the average rate of evidence accumulation, and the threshold. These mechanisms determine both the within-trial dynamics of evidence accumulation and the predicted behavior. Cognitive modelers usually infer what mechanisms vary during decision-making by seeing what parameters vary when a model is fitted to observed behavior. The recent identification of neural activity with evidence accumulation suggests that it may be possible to directly infer what mechanisms vary from an analysis of how neural dynamics vary. However, evidence accumulation is often noisy, and noise complicates the relationship between accumulator dynamics and the underlying mechanisms leading to those dynamics. To understand what kinds of inferences can be made about decision-making mechanisms based on measures of neural dynamics, we measured simulated accumulator model dynamics while systematically varying model parameters. In some cases, decision- making mechanisms can be directly inferred from dynamics, allowing us to distinguish between models that make identical behavioral predictions. In other cases, however, different parameterized mechanisms produce surprisingly similar dynamics, limiting the inferences that can be made based on measuring dynamics alone. Analyzing neural dynamics can provide a powerful tool to resolve model mimicry at the behavioral level, but we caution against drawing inferences based solely on neural analyses. Instead, simultaneous modeling of behavior and neural dynamics provides the most powerful approach to understand decision-making and likely other aspects of cognition and perception. PMID:28392584

  14. Visuospatial Asymmetries Arise from Differences in the Onset Time of Perceptual Evidence Accumulation.

    PubMed

    Newman, Daniel P; Loughnane, Gerard M; Kelly, Simon P; O'Connell, Redmond G; Bellgrove, Mark A

    2017-03-22

    Healthy subjects tend to exhibit a bias of visual attention whereby left hemifield stimuli are processed more quickly and accurately than stimuli appearing in the right hemifield. It has long been held that this phenomenon arises from the dominant role of the right cerebral hemisphere in regulating attention. However, methods that would enable more precise understanding of the mechanisms underpinning visuospatial bias have remained elusive. We sought to finely trace the temporal evolution of spatial biases by leveraging a novel bilateral dot motion detection paradigm. In combination with electroencephalography, this paradigm enables researchers to isolate discrete neural signals reflecting the key neural processes needed for making these detection decisions. These include signals for spatial attention, early target selection, evidence accumulation, and motor preparation. Using this method, we established that three key neural markers accounted for unique between-subject variation in visuospatial bias: hemispheric asymmetry in posterior α power measured before target onset, which is related to the distribution of preparatory attention across the visual field; asymmetry in the peak latency of the early N2c target-selection signal; and, finally, asymmetry in the onset time of the subsequent neural evidence-accumulation process with earlier onsets for left hemifield targets. Our development of a single paradigm to dissociate distinct processing components that track the temporal evolution of spatial biases not only advances our understanding of the neural mechanisms underpinning normal visuospatial attention bias, but may also in the future aid differential diagnoses in disorders of spatial attention. SIGNIFICANCE STATEMENT The significance of this research is twofold. First, it shows that individual differences in how humans direct their attention between left and right space reflects physiological differences in how early the brain starts to accumulate evidence for

  15. Computer-Based Reading Technology in the Classroom: The Affective Influence of Performance Contingent Point Accumulation on 4th Grade Students

    ERIC Educational Resources Information Center

    Putman, S. Michael

    2005-01-01

    The purpose of the present study was to investigate the relationship between the number of Accelerated Reader points accumulated by students and their level of self-efficacy and value of reading. The fourteen week study examined 68 fourth grade students who attended an elementary school in a suburban location near a large Midwestern city.…

  16. Evidence-Based Practice Point-of-Care Resources: A Quantitative Evaluation of Quality, Rigor, and Content.

    PubMed

    Campbell, Jared M; Umapathysivam, Kandiah; Xue, Yifan; Lockwood, Craig

    2015-12-01

    Clinicians and other healthcare professionals need access to summaries of evidence-based information in order to provide effective care to their patients at the point-of-care. Evidence-based practice (EBP) point-of-care resources have been developed and are available online to meet this need. This study aimed to develop a comprehensive list of available EBP point-of-care resources and evaluate their processes and policies for the development of content, in order to provide a critical analysis based upon rigor, transparency and measures of editorial quality to inform healthcare providers and promote quality improvement amongst publishers of EBP resources. A comprehensive and systematic search (Pubmed, CINAHL, and Cochrane Central) was undertaken to identify available EBP point-of-care resources, defined as "web-based medical compendia specifically designed to deliver predigested, rapidly accessible, comprehensive, periodically updated, and evidence-based information (and possibly also guidance) to clinicians." A pair of investigators independently extracted information on general characteristics, content presentation, editorial quality, evidence-based methodology, and breadth and volume. Twenty-seven summary resources were identified, of which 22 met the predefined inclusion criteria for EBP point-of-care resources, and 20 could be accessed for description and assessment. Overall, the upper quartile of EBP point-of-care providers was assessed to be UpToDate, Nursing Reference Centre, Mosby's Nursing Consult, BMJ Best Practice, and JBI COnNECT+. The choice of which EBP point-of-care resources are suitable for an organization is a decision that depends heavily on the unique requirements of that organization and the resources it has available. However, the results presented in this study should enable healthcare providers to make that assessment in a clear, evidence-based manner, and provide a comprehensive list of the available options. © 2015 Sigma Theta Tau

  17. Economic Evidence and Point-of-Care Testing

    PubMed Central

    St John, Andrew; Price, Christopher P

    2013-01-01

    Health economics has been an established feature of the research, policymaking, practice and management in the delivery of healthcare. However its role is increasing as the cost of healthcare begins to drive changes in most healthcare systems. Thus the output from cost effectiveness studies is now being taken into account when making reimbursement decisions, e.g. in Australia and the United Kingdom. Against this background it is also recognised that the health economic tools employed in healthcare, and particularly the output from the use of these tools however, are not always employed in the routine delivery of services. One of the notable consequences of this situation is the poor record of innovation in healthcare with respect to the adoption of new technologies, and the realisation of their benefits. The evidence base for the effectiveness of diagnostic services is well known to be limited, and one consequence of this has been a very limited literature on cost effectiveness. One reason for this situation is undoubtedly the reimbursement strategies employed in laboratory medicine for many years, simplistically based on the complexity of the test procedure, and the delivery as a cost-per-test service. This has proved a disincentive to generate the required evidence, and little effort to generate an integrated investment and disinvestment business case, associated with care pathway changes. Point-of-care testing creates a particularly challenging scenario because, on the one hand, the unit cost-per-test is larger through the loss of the economy of scale offered by automation, whilst it offers the potential of substantial savings through enabling rapid delivery of results, and reduction of facility costs. This is important when many health systems are planning for complete system redesign. We review the literature on economic assessment of point-of-care testing in the context of these developments. PMID:24151342

  18. The 3D Hough Transform for plane detection in point clouds: A review and a new accumulator design

    NASA Astrophysics Data System (ADS)

    Borrmann, Dorit; Elseberg, Jan; Lingemann, Kai; Nüchter, Andreas

    2011-03-01

    The Hough Transform is a well-known method for detecting parameterized objects. It is the de facto standard for detecting lines and circles in 2-dimensional data sets. For 3D it has attained little attention so far. Even for the 2D case high computational costs have lead to the development of numerous variations for the Hough Transform. In this article we evaluate different variants of the Hough Transform with respect to their applicability to detect planes in 3D point clouds reliably. Apart from computational costs, the main problem is the representation of the accumulator. Usual implementations favor geometrical objects with certain parameters due to uneven sampling of the parameter space. We present a novel approach to design the accumulator focusing on achieving the same size for each cell and compare it to existing designs. [Figure not available: see fulltext.

  19. Mitochondrial accumulation of APP and Aβ: significance for Alzheimer disease pathogenesis

    PubMed Central

    Pavlov, Pavel F; Petersen, Camilla Hansson; Glaser, Elzbieta; Ankarcrona, Maria

    2009-01-01

    Accumulating evidence suggest that alterations in energy metabolism are among the earliest events that occur in the Alzheimer disease (AD) affected brain. Energy consumption is drastically decreased in the AD-affected regions of cerebral cortex and hippocampus pointing towards compromised mitochondrial function of neurons within specific brain regions. This is accompanied by an elevated production of reactive oxygen species contributing to increased rates of neuronal loss in the AD-affected brain regions. In this review, we will discuss the role of mitochondrial function and dysfunction in AD. We will focus on the consequences of amyloid precursor protein and amyloid-β peptide accumulation in mitochondria and their involvement in AD pathogenesis. PMID:19725915

  20. Ultrastructural and clinical evidence of subretinal debris accumulation in type 2 macular telangiectasia.

    PubMed

    Cherepanoff, Svetlana; Killingsworth, Murray C; Zhu, Meidong; Nolan, Timothy; Hunyor, Alex P; Young, Stephanie H; Hageman, Gregory S; Gillies, Mark C

    2012-11-01

    To describe subretinal debris found on ultrastructural examination in an eye with macular telangiectasia (MacTel) type 2 and on optical coherence tomography (OCT) in a subset of patients with MacTel type 2. Blocks from the mid-periphery and temporal perifovea of an eye with clinically documented MacTel type 2 were examined with electron microscopy (EM). Cases came from the Sydney centre of the MacTel project and the practices of the authors. On EM examination, subretinal debris was found in the perifovea with accumulation of degenerate photoreceptor elements in the subretinal space. Despite the substantial subretinal debris, there was minimal retinal pigment epithelial (RPE) reaction. Focal defects were seen in the inner limiting membrane in the perifovea. Of the 65 Sydney MacTel project participants, three (5%) had prominent yellow material at the fovea. OCT revealed smooth mounds between the RPE and the ellipsoid region. The material was hyperautofluorescent. This study suggests that subretinal accumulation of photoreceptor debris may be a feature of MacTel type 2. Ultrastructural and OCT evidence of disease beyond the vasculature, involving photoreceptors and Muller cells, is presented.

  1. A segmentation and point-matching enhanced efficient deformable image registration method for dose accumulation between HDR CT images

    NASA Astrophysics Data System (ADS)

    Zhen, Xin; Chen, Haibin; Yan, Hao; Zhou, Linghong; Mell, Loren K.; Yashar, Catheryn M.; Jiang, Steve; Jia, Xun; Gu, Xuejun; Cervino, Laura

    2015-04-01

    Deformable image registration (DIR) of fractional high-dose-rate (HDR) CT images is challenging due to the presence of applicators in the brachytherapy image. Point-to-point correspondence fails because of the undesired deformation vector fields (DVF) propagated from the applicator region (AR) to the surrounding tissues, which can potentially introduce significant DIR errors in dose mapping. This paper proposes a novel segmentation and point-matching enhanced efficient DIR (named SPEED) scheme to facilitate dose accumulation among HDR treatment fractions. In SPEED, a semi-automatic seed point generation approach is developed to obtain the incremented fore/background point sets to feed the random walks algorithm, which is used to segment and remove the AR, leaving empty AR cavities in the HDR CT images. A feature-based ‘thin-plate-spline robust point matching’ algorithm is then employed for AR cavity surface points matching. With the resulting mapping, a DVF defining on each voxel is estimated by B-spline approximation, which serves as the initial DVF for the subsequent Demons-based DIR between the AR-free HDR CT images. The calculated DVF via Demons combined with the initial one serve as the final DVF to map doses between HDR fractions. The segmentation and registration accuracy are quantitatively assessed by nine clinical HDR cases from three gynecological cancer patients. The quantitative analysis and visual inspection of the DIR results indicate that SPEED can suppress the impact of applicator on DIR, and accurately register HDR CT images as well as deform and add interfractional HDR doses.

  2. A segmentation and point-matching enhanced efficient deformable image registration method for dose accumulation between HDR CT images.

    PubMed

    Zhen, Xin; Chen, Haibin; Yan, Hao; Zhou, Linghong; Mell, Loren K; Yashar, Catheryn M; Jiang, Steve; Jia, Xun; Gu, Xuejun; Cervino, Laura

    2015-04-07

    Deformable image registration (DIR) of fractional high-dose-rate (HDR) CT images is challenging due to the presence of applicators in the brachytherapy image. Point-to-point correspondence fails because of the undesired deformation vector fields (DVF) propagated from the applicator region (AR) to the surrounding tissues, which can potentially introduce significant DIR errors in dose mapping. This paper proposes a novel segmentation and point-matching enhanced efficient DIR (named SPEED) scheme to facilitate dose accumulation among HDR treatment fractions. In SPEED, a semi-automatic seed point generation approach is developed to obtain the incremented fore/background point sets to feed the random walks algorithm, which is used to segment and remove the AR, leaving empty AR cavities in the HDR CT images. A feature-based 'thin-plate-spline robust point matching' algorithm is then employed for AR cavity surface points matching. With the resulting mapping, a DVF defining on each voxel is estimated by B-spline approximation, which serves as the initial DVF for the subsequent Demons-based DIR between the AR-free HDR CT images. The calculated DVF via Demons combined with the initial one serve as the final DVF to map doses between HDR fractions. The segmentation and registration accuracy are quantitatively assessed by nine clinical HDR cases from three gynecological cancer patients. The quantitative analysis and visual inspection of the DIR results indicate that SPEED can suppress the impact of applicator on DIR, and accurately register HDR CT images as well as deform and add interfractional HDR doses.

  3. An integrated circuit floating point accumulator

    NASA Technical Reports Server (NTRS)

    Goldsmith, T. C.

    1977-01-01

    Goddard Space Flight Center has developed a large scale integrated circuit (type 623) which can perform pulse counting, storage, floating point compression, and serial transmission, using a single monolithic device. Counts of 27 or 19 bits can be converted to transmitted values of 12 or 8 bits respectively. Use of the 623 has resulted in substantial savaings in weight, volume, and dollar resources on at least 11 scientific instruments to be flown on 4 NASA spacecraft. The design, construction, and application of the 623 are described.

  4. A research protocol for developing a Point-Of-Care Key Evidence Tool 'POCKET': a checklist for multidimensional evidence reporting on point-of-care in vitro diagnostics.

    PubMed

    Huddy, Jeremy R; Ni, Melody; Mavroveli, Stella; Barlow, James; Williams, Doris-Ann; Hanna, George B

    2015-07-10

    Point-of-care in vitro diagnostics (POC-IVD) are increasingly becoming widespread as an acceptable means of providing rapid diagnostic results to facilitate decision-making in many clinical pathways. Evidence in utility, usability and cost-effectiveness is currently provided in a fragmented and detached manner that is fraught with methodological challenges given the disruptive nature these tests have on the clinical pathway. The Point-of-care Key Evidence Tool (POCKET) checklist aims to provide an integrated evidence-based framework that incorporates all required evidence to guide the evaluation of POC-IVD to meet the needs of policy and decisionmakers in the National Health Service (NHS). A multimethod approach will be applied in order to develop the POCKET. A thorough literature review has formed the basis of a robust Delphi process and validation study. Semistructured interviews are being undertaken with POC-IVD stakeholders, including industry, regulators, commissioners, clinicians and patients to understand what evidence is required to facilitate decision-making. Emergent themes will be translated into a series of statements to form a survey questionnaire that aims to reach a consensus in each stakeholder group to what needs to be included in the tool. Results will be presented to a workshop to discuss the statements brought forward and the optimal format for the tool. Once assembled, the tool will be field-tested through case studies to ensure validity and usability and inform refinement, if required. The final version will be published online with a call for comments. Limitations include unpredictable sample representation, development of compromise position rather than consensus, and absence of blinding in validation exercise. The Imperial College Joint Research Compliance Office and the Imperial College Hospitals NHS Trust R&D department have approved the protocol. The checklist tool will be disseminated through a PhD thesis, a website, peer

  5. Accumulating Evidence and Research Organization (AERO) model: a new tool for representing, analyzing, and planning a translational research program.

    PubMed

    Hey, Spencer Phillips; Heilig, Charles M; Weijer, Charles

    2013-05-30

    Maximizing efficiency in drug development is important for drug developers, policymakers, and human subjects. Limited funds and the ethical imperative of risk minimization demand that researchers maximize the knowledge gained per patient-subject enrolled. Yet, despite a common perception that the current system of drug development is beset by inefficiencies, there remain few approaches for systematically representing, analyzing, and communicating the efficiency and coordination of the research enterprise. In this paper, we present the first steps toward developing such an approach: a graph-theoretic tool for representing the Accumulating Evidence and Research Organization (AERO) across a translational trajectory. This initial version of the AERO model focuses on elucidating two dimensions of robustness: (1) the consistency of results among studies with an identical or similar outcome metric; and (2) the concordance of results among studies with qualitatively different outcome metrics. The visual structure of the model is a directed acyclic graph, designed to capture these two dimensions of robustness and their relationship to three basic questions that underlie the planning of a translational research program: What is the accumulating state of total evidence? What has been the translational trajectory? What studies should be done next? We demonstrate the utility of the AERO model with an application to a case study involving the antibacterial agent, moxifloxacin, for the treatment of drug-susceptible tuberculosis. We then consider some possible elaborations for the AERO model and propose a number of ways in which the tool could be used to enhance the planning, reporting, and analysis of clinical trials. The AERO model provides an immediate visual representation of the number of studies done at any stage of research, depicting both the robustness of evidence and the relationship of each study to the larger translational trajectory. In so doing, it makes some of the

  6. High-Value Consults: A Curriculum to Promote Point-of-Care, Evidence-Based Recommendations.

    PubMed

    Nandiwada, Deepa Rani; Kohli, Amar; McNamara, Megan; Smith, Kenneth J; Zimmer, Shanta; McNeil, Melissa; Spagnoletti, Carla; Rubio, Doris; Berlacher, Kathryn

    2017-10-01

    In an era when value-based care is paramount, teaching trainees to explicitly communicate the evidence behind recommendations fosters high-value care (HVC) in the consultation process. To implement an HVC consult curriculum highlighting the need for clear consult questions, evidence-based recommendations to improve consult teaching, clinical decision-making, and the educational value of consults. A pilot curriculum was implemented for residents on cardiology consult electives utilizing faculty and fellows as evidence-based medicine (EBM) coaches. The curriculum included an online module, an EBM teaching point template, EBM presentations on rounds, and "coach" feedback on notes. A total of 15 residents and 4 fellows on cardiology consults participated, and 87% (13 of 15) of residents on consults felt the curriculum was educationally valuable. A total of 80% (72 of 90) of residents on general medicine rotations responded to the survey, and 25 of 72 residents (35%) had a consult with the EBM template. General medicine teams felt the EBM teaching points affected clinical decision-making (48%, 12 of 25) and favored dissemination of the curriculum (90%, 72 of 80). Checklist-guided chart review showed a 22% improvement in evidence-based summaries behind recommendations (7 of 36 precurriculum to 70 of 146 charts postcurriculum, P  = .015). The HVC consult curriculum during a cardiology elective was perceived by residents to influence clinical decision-making and evidence-based recommendations, and was found to be educationally valuable on both parties in the consult process.

  7. Everything should be as simple as possible, but no simpler: towards a protocol for accumulating evidence regarding the active content of health behaviour change interventions.

    PubMed

    Peters, Gjalt-Jorn Ygram; de Bruin, Marijn; Crutzen, Rik

    2015-01-01

    There is a need to consolidate the evidence base underlying our toolbox of methods of behaviour change. Recent efforts to this effect have conducted meta-regressions on evaluations of behaviour change interventions, deriving each method's effectiveness from its association to intervention effect size. However, there are a range of issues that raise concern about whether this approach is actually furthering or instead obstructing the advancement of health psychology theories and the quality of health behaviour change interventions. Using examples from theory, the literature and data from previous meta-analyses, these concerns and their implications are explained and illustrated. An iterative protocol for evidence base accumulation is proposed that integrates evidence derived from both experimental and applied behaviour change research, and combines theory development in experimental settings with theory testing in applied real-life settings. As evidence gathered in this manner accumulates, a cumulative science of behaviour change can develop.

  8. Everything should be as simple as possible, but no simpler: towards a protocol for accumulating evidence regarding the active content of health behaviour change interventions

    PubMed Central

    Peters, Gjalt-Jorn Ygram; de Bruin, Marijn; Crutzen, Rik

    2015-01-01

    There is a need to consolidate the evidence base underlying our toolbox of methods of behaviour change. Recent efforts to this effect have conducted meta-regressions on evaluations of behaviour change interventions, deriving each method's effectiveness from its association to intervention effect size. However, there are a range of issues that raise concern about whether this approach is actually furthering or instead obstructing the advancement of health psychology theories and the quality of health behaviour change interventions. Using examples from theory, the literature and data from previous meta-analyses, these concerns and their implications are explained and illustrated. An iterative protocol for evidence base accumulation is proposed that integrates evidence derived from both experimental and applied behaviour change research, and combines theory development in experimental settings with theory testing in applied real-life settings. As evidence gathered in this manner accumulates, a cumulative science of behaviour change can develop. PMID:25793484

  9. MO-C-17A-11: A Segmentation and Point Matching Enhanced Deformable Image Registration Method for Dose Accumulation Between HDR CT Images

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

    Zhen, X; Chen, H; Zhou, L

    2014-06-15

    Purpose: To propose and validate a novel and accurate deformable image registration (DIR) scheme to facilitate dose accumulation among treatment fractions of high-dose-rate (HDR) gynecological brachytherapy. Method: We have developed a method to adapt DIR algorithms to gynecologic anatomies with HDR applicators by incorporating a segmentation step and a point-matching step into an existing DIR framework. In the segmentation step, random walks algorithm is used to accurately segment and remove the applicator region (AR) in the HDR CT image. A semi-automatic seed point generation approach is developed to obtain the incremented foreground and background point sets to feed the randommore » walks algorithm. In the subsequent point-matching step, a feature-based thin-plate spline-robust point matching (TPS-RPM) algorithm is employed for AR surface point matching. With the resulting mapping, a DVF characteristic of the deformation between the two AR surfaces is generated by B-spline approximation, which serves as the initial DVF for the following Demons DIR between the two AR-free HDR CT images. Finally, the calculated DVF via Demons combined with the initial one serve as the final DVF to map doses between HDR fractions. Results: The segmentation and registration accuracy are quantitatively assessed by nine clinical HDR cases from three gynecological cancer patients. The quantitative results as well as the visual inspection of the DIR indicate that our proposed method can suppress the interference of the applicator with the DIR algorithm, and accurately register HDR CT images as well as deform and add interfractional HDR doses. Conclusions: We have developed a novel and robust DIR scheme that can perform registration between HDR gynecological CT images and yield accurate registration results. This new DIR scheme has potential for accurate interfractional HDR dose accumulation. This work is supported in part by the National Natural ScienceFoundation of China (no 30970866

  10. Accumulate-Repeat-Accumulate-Accumulate-Codes

    NASA Technical Reports Server (NTRS)

    Divsalar, Dariush; Dolinar, Sam; Thorpe, Jeremy

    2004-01-01

    Inspired by recently proposed Accumulate-Repeat-Accumulate (ARA) codes [15], in this paper we propose a channel coding scheme called Accumulate-Repeat-Accumulate-Accumulate (ARAA) codes. These codes can be seen as serial turbo-like codes or as a subclass of Low Density Parity Check (LDPC) codes, and they have a projected graph or protograph representation; this allows for a high-speed iterative decoder implementation using belief propagation. An ARAA code can be viewed as a precoded Repeat-and-Accumulate (RA) code with puncturing in concatenation with another accumulator, where simply an accumulator is chosen as the precoder; thus ARAA codes have a very fast encoder structure. Using density evolution on their associated protographs, we find examples of rate-lJ2 ARAA codes with maximum variable node degree 4 for which a minimum bit-SNR as low as 0.21 dB from the channel capacity limit can be achieved as the block size goes to infinity. Such a low threshold cannot be achieved by RA or Irregular RA (IRA) or unstructured irregular LDPC codes with the same constraint on the maximum variable node degree. Furthermore by puncturing the accumulators we can construct families of higher rate ARAA codes with thresholds that stay close to their respective channel capacity thresholds uniformly. Iterative decoding simulation results show comparable performance with the best-known LDPC codes but with very low error floor even at moderate block sizes.

  11. Accumulate-Repeat-Accumulate-Accumulate Codes

    NASA Technical Reports Server (NTRS)

    Divsalar, Dariush; Dolinar, Samuel; Thorpe, Jeremy

    2007-01-01

    Accumulate-repeat-accumulate-accumulate (ARAA) codes have been proposed, inspired by the recently proposed accumulate-repeat-accumulate (ARA) codes. These are error-correcting codes suitable for use in a variety of wireless data-communication systems that include noisy channels. ARAA codes can be regarded as serial turbolike codes or as a subclass of low-density parity-check (LDPC) codes, and, like ARA codes they have projected graph or protograph representations; these characteristics make it possible to design high-speed iterative decoders that utilize belief-propagation algorithms. The objective in proposing ARAA codes as a subclass of ARA codes was to enhance the error-floor performance of ARA codes while maintaining simple encoding structures and low maximum variable node degree.

  12. Using Time-Varying Evidence to Test Models of Decision Dynamics: Bounded Diffusion vs. the Leaky Competing Accumulator Model

    PubMed Central

    Tsetsos, Konstantinos; Gao, Juan; McClelland, James L.; Usher, Marius

    2012-01-01

    When people make decisions, do they give equal weight to evidence arriving at different times? A recent study (Kiani et al., 2008) using brief motion pulses (superimposed on a random moving dot display) reported a primacy effect: pulses presented early in a motion observation period had a stronger impact than pulses presented later. This observation was interpreted as supporting the bounded diffusion (BD) model and ruling out models in which evidence accumulation is subject to leakage or decay of early-arriving information. We use motion pulses and other manipulations of the timing of the perceptual evidence in new experiments and simulations that support the leaky competing accumulator (LCA) model as an alternative to the BD model. While the LCA does include leakage, we show that it can exhibit primacy as a result of competition between alternatives (implemented via mutual inhibition), when the inhibition is strong relative to the leak. Our experiments replicate the primacy effect when participants must be prepared to respond quickly at the end of a motion observation period. With less time pressure, however, the primacy effect is much weaker. For 2 (out of 10) participants, a primacy bias observed in trials where the motion observation period is short becomes weaker or reverses (becoming a recency effect) as the observation period lengthens. Our simulation studies show that primacy is equally consistent with the LCA or with BD. The transition from primacy-to-recency can also be captured by the LCA but not by BD. Individual differences and relations between the LCA and other models are discussed. PMID:22701399

  13. Evidence accumulation in decision making: unifying the "take the best" and the "rational" models.

    PubMed

    Lee, Michael D; Cummins, Tarrant D R

    2004-04-01

    An evidence accumulation model of forced-choice decision making is proposed to unify the fast and frugal take the best (TTB) model and the alternative rational (RAT) model with which it is usually contrasted. The basic idea is to treat the TTB model as a sequential-sampling process that terminates as soon as any evidence in favor of a decision is found and the rational approach as a sequential-sampling process that terminates only when all available information has been assessed. The unified TTB and RAT models were tested in an experiment in which participants learned to make correct judgments for a set of real-world stimuli on the basis of feedback, and were then asked to make additional judgments without feedback for cases in which the TTB and the rational models made different predictions. The results show that, in both experiments, there was strong intraparticipant consistency in the use of either the TTB or the rational model but large interparticipant differences in which model was used. The unified model is shown to be able to capture the differences in decision making across participants in an interpretable way and is preferred by the minimum description length model selection criterion.

  14. Regional Greenland accumulation variability from Operation IceBridge airborne accumulation radar

    NASA Astrophysics Data System (ADS)

    Lewis, Gabriel; Osterberg, Erich; Hawley, Robert; Whitmore, Brian; Marshall, Hans Peter; Box, Jason

    2017-03-01

    The mass balance of the Greenland Ice Sheet (GrIS) in a warming climate is of critical interest to scientists and the general public in the context of future sea-level rise. An improved understanding of temporal and spatial variability of snow accumulation will reduce uncertainties in GrIS mass balance models and improve projections of Greenland's contribution to sea-level rise, currently estimated at 0.089 ± 0.03 m by 2100. Here we analyze 25 NASA Operation IceBridge accumulation radar flights totaling > 17 700 km from 2013 to 2014 to determine snow accumulation in the GrIS dry snow and percolation zones over the past 100-300 years. IceBridge accumulation rates are calculated and used to validate accumulation rates from three regional climate models. Averaged over all 25 flights, the RMS difference between the models and IceBridge accumulation is between 0.023 ± 0.019 and 0.043 ± 0.029 m w.e. a-1, although each model shows significantly larger differences from IceBridge accumulation on a regional basis. In the southeast region, for example, the Modèle Atmosphérique Régional (MARv3.5.2) overestimates by an average of 20.89 ± 6.75 % across the drainage basin. Our results indicate that these regional differences between model and IceBridge accumulation are large enough to significantly alter GrIS surface mass balance estimates. Empirical orthogonal function analysis suggests that the first two principal components account for 33 and 19 % of the variance, and correlate with the Atlantic Multidecadal Oscillation (AMO) and wintertime North Atlantic Oscillation (NAO), respectively. Regions that disagree strongest with climate models are those in which we have the fewest IceBridge data points, requiring additional in situ measurements to verify model uncertainties.

  15. Accumulating Evidence for a Drug–Drug Interaction Between Methotrexate and Proton Pump Inhibitors

    PubMed Central

    Mackey, Ann Corken; Kluetz, Paul; Jappar, Dilara; Korvick, Joyce

    2012-01-01

    Background. A number of medications are known to interact with methotrexate through various mechanisms. The aim of this article is to apprise practitioners of a new labeling change based on the accumulating evidence for a possible drug–drug interaction between methotrexate (primarily at high doses) and proton pump inhibitors (PPIs). Methods. The U.S. Food and Drug Administration (FDA) Adverse Event Reporting System (AERS) database of spontaneous adverse event reports and the published literature were searched for cases reporting an interaction between methotrexate and PPIs. Results. A search of the AERS database and existing literature found several individual case reports of drug–drug interactions and three additional supportive studies that suggest potential underlying mechanisms for the interaction. Conclusion. There is evidence to suggest that concomitant use of methotrexate (primarily at high doses) with PPIs such as omeprazole, esomeprazole, and pantoprazole may decrease methotrexate clearance, leading to elevated serum levels of methotrexate and/or its metabolite hydroxymethotrexate, possibly leading to methotrexate toxicities. In several case reports, no methotrexate toxicity was found when a histamine H2 blocker was substituted for a PPI. Based on the reviewed data, the FDA updated the methotrexate label to include the possible drug–drug interaction between high-dose methotrexate and PPIs. Physicians should be alerted to this potential drug–drug interaction in patients receiving concomitant high-dose methotrexate and PPIs. PMID:22477728

  16. Point-of-care ultrasound (POCUS): unnecessary gadgetry or evidence-based medicine?

    PubMed

    Smallwood, Nicholas; Dachsel, Martin

    2018-06-01

    Over the last decade there has been increasing interest and enthusiasm in point-of-care ultrasound (POCUS) as an aide to traditional examination techniques in assessing acutely unwell adult patients. However, it currently remains the domain of a relatively small handful of physicians within the UK. There are numerous reasons for this, notably a lack of training pathways and supervisors but also a lack of understanding of the evidence base behind this imaging modality. This review article aims to explore some of the evidence base behind POCUS for a number of medical pathologies, and where possible compare it to evidenced traditional examination techniques. We discuss the issues around training in bedside ultrasound and recommend a push to integrate POCUS training into internal medicine curricula and support trainers to comprehensively deliver this. © Royal College of Physicians 2018. All rights reserved.

  17. Review on the APP/PS1KI mouse model: intraneuronal Abeta accumulation triggers axonopathy, neuron loss and working memory impairment.

    PubMed

    Bayer, T A; Wirths, O

    2008-02-01

    Accumulating evidence points to an important role of intraneuronal Abeta as a trigger of the pathological cascade of events leading to neurodegeneration and eventually to Alzheimer's disease (AD) with its typical clinical symptoms, like memory impairment and change in personality. As a new concept, intraneuronal accumulation of Abeta instead of extracellular Abeta deposition has been introduced to be the disease-triggering event in AD. The present review compiles current knowledge on the amyloid precursor protein (APP)/PS1KI mouse model with early and massive intraneuronal Abeta42 accumulation: (1) The APP/PS1KI mouse model exhibits early robust brain and spinal cord axonal degeneration and hippocampal CA1 neuron loss. (2) At the same time-point, a dramatic, age-dependent reduced ability to perform working memory and motor tasks is observed. (3) The APP/PS1KI mice are smaller and show development of a thoracolumbar kyphosis, together with an incremental loss of body weight. (4) Onset of the observed behavioral alterations correlates well with robust axonal degeneration in brain and spinal cord and with abundant hippocampal CA1 neuron loss.

  18. Accumulate repeat accumulate codes

    NASA Technical Reports Server (NTRS)

    Abbasfar, A.; Divsalar, D.; Yao, K.

    2004-01-01

    In this paper we propose an innovative channel coding scheme called Accumulate Repeat Accumulate codes. This class of codes can be viewed as trubo-like codes, namely a double serial concatenation of a rate-1 accumulator as an outer code, a regular or irregular repetition as a middle code, and a punctured accumulator as an inner code.

  19. Restriction point control of cell growth by a labile protein: evidence for increased stability in transformed cells.

    PubMed Central

    Campisi, J; Medrano, E E; Morreo, G; Pardee, A B

    1982-01-01

    It has been proposed that animal cells must accumulate a labile protein(s) before they can pass the restriction (R) point in the G1 phase of the cell cycle [Rossow, P. W., Riddle, V. G. H. & Pardee, A. B. (1979) Proc. Natl. Acad. Sci. USA 76, 4446--4450]. Here, we present evidence that this R protein acquires increased stability in transformed 3T3 cells, thereby allowing these cells to continue growth under conditions that arrest untransformed cells. Low doses of cycloheximide or histidinol drastically reduced the rate at which normal 3T3 (A31) fibroblasts in early G1 could enter DNA synthesis. These drugs had less effect on entry of two tumorigenic A31 derivatives, BPA31 and SVA31, in S, although measurement of [3H]leucine incorporation showed that the inhibitors were equally effective in the three cell lines. The hypothesis is that the transformed lines are less sensitive because moderate inhibition of their R protein synthesis is compensated by lower rates of protein degradation. To test this idea, we completely inhibited cytoplasmic protein synthesis for several hours shortly before A31 and BPA31 cells had reached the R point. After removal of inhibitor, A31 cells showed delays in the onset of S that were in excess of the inhibitor pulse, consistent with decay of labile protein during the pulse. BPA31 cells showed no excess delays, suggesting a much more stable R protein. The half-life of the R protein was estimated as 2.5 hr in A31 cells, indicating that, in these cells, R protein synthesis starts at the beginning of G1. In the BPA31 cells the R protein showed no signs of decay for at least 8 hr. PMID:6952194

  20. Automatic indexing and retrieval of encounter-specific evidence for point-of-care support.

    PubMed

    O'Sullivan, Dympna M; Wilk, Szymon A; Michalowski, Wojtek J; Farion, Ken J

    2010-08-01

    Evidence-based medicine relies on repositories of empirical research evidence that can be used to support clinical decision making for improved patient care. However, retrieving evidence from such repositories at local sites presents many challenges. This paper describes a methodological framework for automatically indexing and retrieving empirical research evidence in the form of the systematic reviews and associated studies from The Cochrane Library, where retrieved documents are specific to a patient-physician encounter and thus can be used to support evidence-based decision making at the point of care. Such an encounter is defined by three pertinent groups of concepts - diagnosis, treatment, and patient, and the framework relies on these three groups to steer indexing and retrieval of reviews and associated studies. An evaluation of the indexing and retrieval components of the proposed framework was performed using documents relevant for the pediatric asthma domain. Precision and recall values for automatic indexing of systematic reviews and associated studies were 0.93 and 0.87, and 0.81 and 0.56, respectively. Moreover, precision and recall for the retrieval of relevant systematic reviews and associated studies were 0.89 and 0.81, and 0.92 and 0.89, respectively. With minor modifications, the proposed methodological framework can be customized for other evidence repositories. Copyright 2010 Elsevier Inc. All rights reserved.

  1. Imaging study on acupuncture points

    NASA Astrophysics Data System (ADS)

    Yan, X. H.; Zhang, X. Y.; Liu, C. L.; Dang, R. S.; Ando, M.; Sugiyama, H.; Chen, H. S.; Ding, G. H.

    2009-09-01

    The topographic structures of acupuncture points were investigated by using the synchrotron radiation based Dark Field Image (DFI) method. Four following acupuncture points were studied: Sanyinjiao, Neiguan, Zusanli and Tianshu. We have found that at acupuncture point regions there exists the accumulation of micro-vessels. The images taken in the surrounding tissue out of the acupuncture points do not show such kind of structure. It is the first time to reveal directly the specific structure of acupuncture points by X-ray imaging.

  2. Crustal strain accumulation on Southern Basin and Range Province faults modulated by distant plate boundary earthquakes? Evidence from geodesy, seismic imaging, and paleoseismology

    NASA Astrophysics Data System (ADS)

    Bennett, R. A.; Shirzaei, M.; Broermann, J.; Spinler, J. C.; Holland, A. A.; Pearthree, P.

    2014-12-01

    GPS in Arizona reveals a change in the pattern of crustal strain accumulation in 2010 and based on viscoelastic modeling appears to be associated with the distant M7.2 El Mayor-Cucapah (EMC) earthquake in Baja California, Mexico. GPS data collected between 1999 and 2009 near the Santa Rita normal fault in SE Arizona reveal a narrow zone of crustal deformation coincident with the fault trace, delineated by W-NW facing Pleistocene fault scarps of heights 1 to 7 m. The apparent deformation zone is also seen in a preliminary InSAR interferogram. Total motion across the zone inferred using an elastic block model constrained by the pre-2010 GPS measurements is ~1 mm/yr in a sense consistent with normal fault motion. However, continuous GPS measurements throughout Arizona reveal pronounced changes in crustal velocity following the EMC earthquake, such that the relative motion across the Santa Rita fault post-2010 is negligible. Paleoseismic evidence indicates that mapped Santa Rita fault scarps were formed by two or more large magnitude (M6.7 to M7.6) surface rupturing normal-faulting earthquakes 60 to 100 kyrs ago. Seismic refraction and reflection data constrained by deep (~800 m) well log data provide evidence of progressive, possibly intermittent, displacement on the fault through time. The rate of strain accumulation observed geodetically prior to 2010, if constant over the past 60 to 100 kyrs, would imply an untenable minimum slip rate deficit of 60 to 100 m since the most recent earthquake. One explanation for the available geodetic, seismic, and paleoseismic evidence is that strain accumulation is modulated by viscoelastic relaxation associated with frequent large magnitude earthquakes in the Salton Trough region, episodically inhibiting the accumulation of elastic strain required to generate large earthquakes on the Santa Rita and possibly other faults in the Southern Basin and Range. An important question is thus for how long the postseismic velocity changes

  3. Evidence-based medicine: medical librarians providing evidence at the point of care.

    PubMed

    Yaeger, Lauren H; Kelly, Betsy

    2014-01-01

    Evidence-based medicine is the conscientious, explicit, and judicious use of current best evidence in making decisions about the care of individual patients. .. by best available external clinical evidence we mean clinically relevant research.' Health care reform authorized by the Affordable Care Act is based on the belief that evidence-based practice (EBP) generates cost savings due to the delivery of more effective care.2 Medical librarians, skilled in identifying appropriate resources and working with multiple complex interfaces, can support clinicians' efforts to practice evidence based medicine by providing time and expertise in articulating the clinical question and identifying the best evidence.

  4. Evidence that the Great Pacific Garbage Patch is rapidly accumulating plastic.

    PubMed

    Lebreton, L; Slat, B; Ferrari, F; Sainte-Rose, B; Aitken, J; Marthouse, R; Hajbane, S; Cunsolo, S; Schwarz, A; Levivier, A; Noble, K; Debeljak, P; Maral, H; Schoeneich-Argent, R; Brambini, R; Reisser, J

    2018-03-22

    Ocean plastic can persist in sea surface waters, eventually accumulating in remote areas of the world's oceans. Here we characterise and quantify a major ocean plastic accumulation zone formed in subtropical waters between California and Hawaii: The Great Pacific Garbage Patch (GPGP). Our model, calibrated with data from multi-vessel and aircraft surveys, predicted at least 79 (45-129) thousand tonnes of ocean plastic are floating inside an area of 1.6 million km 2 ; a figure four to sixteen times higher than previously reported. We explain this difference through the use of more robust methods to quantify larger debris. Over three-quarters of the GPGP mass was carried by debris larger than 5 cm and at least 46% was comprised of fishing nets. Microplastics accounted for 8% of the total mass but 94% of the estimated 1.8 (1.1-3.6) trillion pieces floating in the area. Plastic collected during our study has specific characteristics such as small surface-to-volume ratio, indicating that only certain types of debris have the capacity to persist and accumulate at the surface of the GPGP. Finally, our results suggest that ocean plastic pollution within the GPGP is increasing exponentially and at a faster rate than in surrounding waters.

  5. Neural chronometry and coherency across speed-accuracy demands reveal lack of homomorphism between computational and neural mechanisms of evidence accumulation.

    PubMed

    Heitz, Richard P; Schall, Jeffrey D

    2013-10-19

    The stochastic accumulation framework provides a mechanistic, quantitative account of perceptual decision-making and how task performance changes with experimental manipulations. Importantly, it provides an elegant account of the speed-accuracy trade-off (SAT), which has long been the litmus test for decision models, and also mimics the activity of single neurons in several key respects. Recently, we developed a paradigm whereby macaque monkeys trade speed for accuracy on cue during visual search task. Single-unit activity in frontal eye field (FEF) was not homomorphic with the architecture of models, demonstrating that stochastic accumulators are an incomplete description of neural activity under SAT. This paper summarizes and extends this work, further demonstrating that the SAT leads to extensive, widespread changes in brain activity never before predicted. We will begin by reviewing our recently published work that establishes how spiking activity in FEF accomplishes SAT. Next, we provide two important extensions of this work. First, we report a new chronometric analysis suggesting that increases in perceptual gain with speed stress are evident in FEF synaptic input, implicating afferent sensory-processing sources. Second, we report a new analysis demonstrating selective influence of SAT on frequency coupling between FEF neurons and local field potentials. None of these observations correspond to the mechanics of current accumulator models.

  6. Point-of-Care Hemoglobin A1c Testing: An Evidence-Based Analysis

    PubMed Central

    2014-01-01

    Background The increasing prevalence of diabetes in Ontario means that there will be growing demand for hemoglobin A1c (HbA1c) testing to monitor glycemic control for the management of this chronic disease. Testing HbA1c where patients receive their diabetes care may improve system efficiency if the results from point-of-care HbA1c testing are comparable to those from laboratory HbA1c measurements. Objectives To review the correlation between point-of-care HbA1c testing and laboratory HbA1c measurement in patients with diabetes in clinical settings. Data Sources The literature search included studies published between January 2003 and June 2013. Search terms included glycohemoglobin, hemoglobin A1c, point of care, and diabetes. Review Methods Studies were included if participants had diabetes; if they compared point-of-care HbA1c devices (licensed by Health Canada and available in Canada) with laboratory HbA1c measurement (reference method); if they performed point-of-care HbA1c testing using capillary blood samples (finger pricks) and laboratory HbA1c measurement using venous blood samples within 7 days; and if they reported a correlation coefficient between point-of-care HbA1c and laboratory HbA1c results. Results Three point-of-care HbA1c devices were reviewed in this analysis: Bayer's A1cNow+, Bio-Rad's In2it, and Siemens’ DCA Vantage. Five observational studies met the inclusion criteria. The pooled results showed a positive correlation between point-of-care HbA1c testing and laboratory HbA1c measurement (correlation coefficient, 0.967; 95% confidence interval, 0.960–0.973). Limitations Outcomes were limited to the correlation coefficient, as this was a commonly reported measure of analytical performance in the literature. Results should be interpreted with caution due to risk of bias related to selection of participants, reference standards, and the multiple steps involved in POC HbA1c testing. Conclusions Moderate quality evidence showed a positive

  7. Sediment accumulation on the Southern California Bight continental margin during the twentieth century

    USGS Publications Warehouse

    Alexander, C.R.; Lee, H.J.

    2009-01-01

    Sediment discharged into the portion of the Southern California Bight extending from Santa Barbara to Dana Point enters a complex system of semi-isolated coastal cells, narrow continental shelves, submarine canyons, and offshore basins. On both the Santa Monica and San Pedro margins, 210Pb accumulation rates decrease in an offshore direction (from ??0.5 g cm-2yr-1 to 0.02 g cm-2yr -1), in concert with a fining in sediment grain size (from 4.5?? to 8.5??), suggesting that offshore transport of wave-resuspended material occurs as relatively dilute nepheloid layers and that hemiplegic sedimentation dominates the supply of sediment to the outer shelf, slope, and basins. Together, these areas are effectively sequestering up to 100% of the annual fluvial input. In contrast to the Santa Monica margin, which does not display evidence of mass wasting as an important process of sediment delivery and redistribution, the San Pedro margin does provide numerous examples of failures and mass wasting, suggesting that intraslope sediment redistribution may play a more important role there. Basin deposits in both areas exhibit evidence of turbidites tentatively associated with both major floods and earthquakes, sourced from either the Redondo Canyon (San Pedro Basin) or Dume Canyon (Santa Monica Basin). On the Palos Verdes shelf, sediment-accumulation rates decrease along and across the shelf away from the White's Point outfall, which has been a major source of contaminants to the shelf deposits. Accumulation rates prior to the construction of the outfall were ??0.2 g cm-2yr-1 and increased 1.5-3.7 times during peak discharges from the outfall in 1971. The distal rate of accumulation has decreased by ??50%, from 0.63 g cm -2yr-1 during the period 1971-1992 to 0.29 g cm -2yr-1 during the period 1992-2003. The proximal rate of accumulation, however, has only decreased ??10%, from 0.83 g cm -2yr-1 during the period 1971-1992 to 0.73 g cm -2yr-1 during the period 1992-2003. Effluent

  8. Eye-hand coordination during a double-step task: evidence for a common stochastic accumulator

    PubMed Central

    Gopal, Atul

    2015-01-01

    Many studies of reaching and pointing have shown significant spatial and temporal correlations between eye and hand movements. Nevertheless, it remains unclear whether these correlations are incidental, arising from common inputs (independent model); whether these correlations represent an interaction between otherwise independent eye and hand systems (interactive model); or whether these correlations arise from a single dedicated eye-hand system (common command model). Subjects were instructed to redirect gaze and pointing movements in a double-step task in an attempt to decouple eye-hand movements and causally distinguish between the three architectures. We used a drift-diffusion framework in the context of a race model, which has been previously used to explain redirect behavior for eye and hand movements separately, to predict the pattern of eye-hand decoupling. We found that the common command architecture could best explain the observed frequency of different eye and hand response patterns to the target step. A common stochastic accumulator for eye-hand coordination also predicts comparable variances, despite significant difference in the means of the eye and hand reaction time (RT) distributions, which we tested. Consistent with this prediction, we observed that the variances of the eye and hand RTs were similar, despite much larger hand RTs (∼90 ms). Moreover, changes in mean eye RTs, which also increased eye RT variance, produced a similar increase in mean and variance of the associated hand RT. Taken together, these data suggest that a dedicated circuit underlies coordinated eye-hand planning. PMID:26084906

  9. Association of Lipid Accumulation Product with Cardio-Metabolic Risk Factors in Postmenopausal Women.

    PubMed

    Namazi Shabestari, Alireza; Asadi, Mojgan; Jouyandeh, Zahra; Qorbani, Mostafa; Kelishadi, Roya

    2016-06-01

    The lipid accumulation product is a novel, safe and inexpensive index of central lipid over accumulation based on waist circumference and fasting concentration of circulating triglycerides. This study was designed to investigate the ability of lipid accumulation product to predict Cardio-metabolic risk factors in postmenopausal women. In this Cross-sectional study, 264 postmenopausal women by using convenience sampling method were selected from menopause clinic in Tehran. Cardio-metabolic risk factors were measured, and lipid accumulation product (waist-58×triglycerides [nmol/L]) was calculated. Optimal cut-off point of lipid accumulation product for predicting metabolic syndrome was estimated by ROC (Receiver-operating characteristic) curve analysis. Metabolic syndrome was diagnosed in 41.2% of subjects. Optimal cut-off point of lipid accumulation product for predicting metabolic syndrome was 47.63 (sensitivity:75%; specificity:77.9%). High lipid accumulation product increases risk of all Cardio-metabolic risk factors except overweight, high Total Cholesterol, high Low Density Lipoprotein Cholesterol and high Fasting Blood Sugar in postmenopausal women. Our findings show that lipid accumulation product is associated with metabolic syndrome and some Cardio-metabolic risk factors Also lipid accumulation product may have been a useful tool for predicting cardiovascular disease and metabolic syndrome risk in postmenopausal women.

  10. Evidence and age-related distribution of mtDNA D-loop point mutations in skeletal muscle from healthy subjects and mitochondrial patients.

    PubMed

    Del Bo, Roberto; Bordoni, Andreina; Martinelli Boneschi, Filippo; Crimi, Marco; Sciacco, Monica; Bresolin, Nereo; Scarlato, Guglielmo; Comi, Giacomo Pietri

    2002-10-15

    The progressive accumulation of mitochondrial DNA (mtDNA) alterations, ranging from single mutations to large-scale deletions, in both the normal ageing process and pathological conditions is a relevant phenomenon in terms of frequency and heteroplasmic degree. Recently, two point mutations (A189G and T408A) within the Displacement loop (D-loop) region, the control region for mtDNA replication, were shown to occur in skeletal muscles from aged individuals. We evaluated the presence and the heteroplasmy levels of these two mutations in muscle biopsies from 91 unrelated individuals of different ages (21 healthy subjects and 70 patients affected by mitochondrial encephalomyopathies). Overall, both mutations significantly accumulate with age. However, a different relationship was discovered among the different subgroups of patients: a higher number of A189G positive subjects younger than 53 years was detected in the subgroup of multiple-deleted patients; furthermore, a trend towards an increased risk for the mutations was evidenced among patients carrying multiple deletions when compared to healthy controls. These findings support the idea that a common biological mechanism determines the accumulation of somatic point mutations in the D-loop region, both in healthy subjects and in mitochondrial myopathy patients. At the same time, it appears that disorders caused by mutations of nuclear genes controlling mtDNA replication (the "mtDNA multiple deletions" syndromes) present a temporal advantage to mutate in the D-loop region. This observation may be relevant to the definition of the molecular pathogenesis of these latter syndromes. Copyright 2002 Elsevier Science B.V.

  11. 40 CFR 262.34 - Accumulation time.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...: (1) The waste is placed: (i) In containers and the generator complies with the applicable... for inspection on each container; (3) While being accumulated on-site, each container and tank is... listed in § 261.31 or § 261.33(e) in containers at or near any point of generation where wastes initially...

  12. 40 CFR 262.34 - Accumulation time.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...: (1) The waste is placed: (i) In containers and the generator complies with the applicable... for inspection on each container; (3) While being accumulated on-site, each container and tank is... listed in § 261.31 or § 261.33(e) in containers at or near any point of generation where wastes initially...

  13. 40 CFR 262.34 - Accumulation time.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...: (1) The waste is placed: (i) In containers and the generator complies with the applicable... for inspection on each container; (3) While being accumulated on-site, each container and tank is... listed in § 261.31 or § 261.33(e) in containers at or near any point of generation where wastes initially...

  14. 40 CFR 262.34 - Accumulation time.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...: (1) The waste is placed: (i) In containers and the generator complies with the applicable... for inspection on each container; (3) While being accumulated on-site, each container and tank is... listed in § 261.31 or § 261.33(e) in containers at or near any point of generation where wastes initially...

  15. 40 CFR 262.34 - Accumulation time.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...: (1) The waste is placed: (i) In containers and the generator complies with the applicable... for inspection on each container; (3) While being accumulated on-site, each container and tank is... listed in § 261.31 or § 261.33(e) in containers at or near any point of generation where wastes initially...

  16. Accumulate repeat accumulate codes

    NASA Technical Reports Server (NTRS)

    Abbasfar, Aliazam; Divsalar, Dariush; Yao, Kung

    2004-01-01

    In this paper we propose an innovative channel coding scheme called 'Accumulate Repeat Accumulate codes' (ARA). This class of codes can be viewed as serial turbo-like codes, or as a subclass of Low Density Parity Check (LDPC) codes, thus belief propagation can be used for iterative decoding of ARA codes on a graph. The structure of encoder for this class can be viewed as precoded Repeat Accumulate (RA) code or as precoded Irregular Repeat Accumulate (IRA) code, where simply an accumulator is chosen as a precoder. Thus ARA codes have simple, and very fast encoder structure when they representing LDPC codes. Based on density evolution for LDPC codes through some examples for ARA codes, we show that for maximum variable node degree 5 a minimum bit SNR as low as 0.08 dB from channel capacity for rate 1/2 can be achieved as the block size goes to infinity. Thus based on fixed low maximum variable node degree, its threshold outperforms not only the RA and IRA codes but also the best known LDPC codes with the dame maximum node degree. Furthermore by puncturing the accumulators any desired high rate codes close to code rate 1 can be obtained with thresholds that stay close to the channel capacity thresholds uniformly. Iterative decoding simulation results are provided. The ARA codes also have projected graph or protograph representation that allows for high speed decoder implementation.

  17. Accumulation of 5-Oxoproline in Mouse Tissues After Inhibition of 5-Oxoprolinase and Administration of Amino Acids: Evidence for Function of the γ-Glutamyl Cycle*

    PubMed Central

    Van Der Werf, Paul; Stephani, Ralph A.; Meister, Alton

    1974-01-01

    5-Oxoprolinase catalyzes the conversion of 5-oxo-L-proline (L-pyroglutamate, L-2-pyrrolidone-5-carboxylate) to L-glutamate with concomitant stoichiometric cleavage of ATP to ADP and inorganic orthophosphate. In this reaction, a step in the γ-glutamyl cycle, 5-oxoproline (formed by the action of γ-glutamylcyclotransferase on γ-glutamyl amino acids, which are in turn formed by transpeptidation of amino acids with glutathione), is made available for glutathione synthesis. When mice are injected with L-2-imidazolidone-4-carboxylate, a competitive inhibitor of 5-oxoprolinase, they accumulate 5-oxoproline in their tissues (kidney, liver, brain, and eye) and excrete it in the urine. Mice given the inhibitor together with one of several L-amino acids accumulate and excrete much more 5-oxoproline than when they are given the inhibitor alone. Such augmentation of 5-oxoproline accumulation offers evidence for the function of the γ-glutamyl cycle in vivo and supports the view that 5-oxoproline is a quantitatively significant metabolite. Images PMID:4151516

  18. Reference-dependent preferences for maternity wards: an exploration of two reference points.

    PubMed

    Neuman, Einat

    2014-01-01

    It is now well established that a person's valuation of the benefit from an outcome of a decision is determined by the intrinsic "consumption utility" of the outcome itself and also by the relation of the outcome to some reference point. The most notable expression of such reference-dependent preferences is loss aversion. What precisely this reference point is, however, is less clear. This paper claims and provides empirical evidence for the existence of more than one reference point. Using a discrete choice experiment in the Israeli public health-care sector, within a sample of 219 women who had given birth, it is shown that respondents refer to two reference points : (i) a constant scenario that is used in the experiment; and (ii) also the actual state of the quantitative attributes of the service (number of beds in room of hospitalization; and travel time from residence to hospital). In line with the loss aversion theory, it is also shown that losses (vis-à-vis the constant scenario and vis-à-vis the actual state) accumulate and have reinforced effects, while gains do not.

  19. Inference and interrogation of a coregulatory network in the context of lipid accumulation in Yarrowia lipolytica.

    PubMed

    Trébulle, Pauline; Nicaud, Jean-Marc; Leplat, Christophe; Elati, Mohamed

    2017-01-01

    Complex phenotypes, such as lipid accumulation, result from cooperativity between regulators and the integration of multiscale information. However, the elucidation of such regulatory programs by experimental approaches may be challenging, particularly in context-specific conditions. In particular, we know very little about the regulators of lipid accumulation in the oleaginous yeast of industrial interest Yarrowia lipolytica . This lack of knowledge limits the development of this yeast as an industrial platform, due to the time-consuming and costly laboratory efforts required to design strains with the desired phenotypes. In this study, we aimed to identify context-specific regulators and mechanisms, to guide explorations of the regulation of lipid accumulation in Y. lipolytica . Using gene regulatory network inference, and considering the expression of 6539 genes over 26 time points from GSE35447 for biolipid production and a list of 151 transcription factors, we reconstructed a gene regulatory network comprising 111 transcription factors, 4451 target genes and 17048 regulatory interactions (YL-GRN-1) supported by evidence of protein-protein interactions. This study, based on network interrogation and wet laboratory validation (a) highlights the relevance of our proposed measure, the transcription factors influence, for identifying phases corresponding to changes in physiological state without prior knowledge (b) suggests new potential regulators and drivers of lipid accumulation and (c) experimentally validates the impact of six of the nine regulators identified on lipid accumulation, with variations in lipid content from +43.2% to -31.2% on glucose or glycerol.

  20. [Lorenz was right, or does aggressive energy accumulate?].

    PubMed

    Kudriavtseva, N N

    2004-06-01

    Evidence supporting the fact that inherited mechanisms of regulation of aggressive behavior as a result of a repeated experience of aggression ending in victories are transformed into pathological mechanisms based on accumulation of neurochemical shifts in the brain, enhancing aggressiveness, and forming aggressive motivation in aggressive winners. This confirms the concept by Lorenz on the existence of a mechanism (but not instinct) of a spontaneous accumulation of aggressive energy that needs a discharge and formation of permanent attraction to manifestation of aggression.

  1. Geomorphic control of landscape carbon accumulation

    USGS Publications Warehouse

    Rosenbloom, N.A.; Harden, J.W.; Neff, J.C.; Schimel, D.S.

    2006-01-01

    We use the CREEP process-response model to simulate soil organic carbon accumulation in an undisturbed prairie site in Iowa. Our primary objectives are to identify spatial patterns of carbon accumulation, and explore the effect of erosion on basin-scale C accumulation. Our results point to two general findings. First, redistribution of soil carbon by erosion results in a net increase in basin-wide carbon storage relative to a noneroding environment. Landscape-average mean residence times are increased in an eroding landscape owing to the burial/preservation of otherwise labile C. Second, field observations taken along a slope transect may overlook significant intraslope variations in carbon accumulation. Spatial patterns of modeled deep C accumulation are complex. While surface carbon with its relatively short equilibration time is predictable from surface properties, deep carbon is strongly influenced by the landscape's geomorphic and climatic history, resulting in wide spatial variability. Convergence and divergence associated with upland swales and interfluves result in bimodal carbon distributions in upper and mid slopes; variability in carbon storage within modeled mid slopes was as high as simulated differences between erosional shoulders and depositional valley bottoms. The bimodality of mid-slope C variability in the model suggests that a three-dimensional sampling strategy is preferable over the traditional two-dimensional analog or "catena" approach. Copyright 2006 by the American Geophysical Union.

  2. Type of Evidence Behind Point-of-Care Clinical Information Products: A Bibliometric Analysis

    PubMed Central

    2011-01-01

    Background Point-of-care (POC) products are widely used as information reference tools in the clinical setting. Although usability, scope of coverage, ability to answer clinical questions, and impact on health outcomes have been studied, no comparative analysis of the characteristics of the references, the evidence for the content, in POC products is available. Objective The objective of this study was to compare the type of evidence behind five POC clinical information products. Methods This study is a comparative bibliometric analysis of references cited in monographs in POC products. Five commonly used products served as subjects for the study: ACP PIER, Clinical Evidence, DynaMed, FirstCONSULT, and UpToDate. The four clinical topics examined to identify content in the products were asthma, hypertension, hyperlipidemia, and carbon monoxide poisoning. Four indicators were measured: distribution of citations, type of evidence, product currency, and citation overlap. The type of evidence was determined based primarily on the publication type found in the MEDLINE bibliographic record, as well as the Medical Subject Headings (MeSH), both assigned by the US National Library of Medicine. MeSH is the controlled vocabulary used for indexing articles in MEDLINE/PubMed. Results FirstCONSULT had the greatest proportion of references with higher levels of evidence publication types such as systematic review and randomized controlled trial (137/153, 89.5%), although it contained the lowest total number of references (153/2330, 6.6%). DynaMed had the largest total number of references (1131/2330, 48.5%) and the largest proportion of current (2007-2009) references (170/1131, 15%). The distribution of references cited for each topic varied between products. For example, asthma had the most references listed in DynaMed, Clinical Evidence, and FirstCONSULT, while hypertension had the most references in UpToDate and ACP PIER. An unexpected finding was that the rate of citation

  3. Deleterious effects of neuronal accumulation of glycogen in flies and mice

    PubMed Central

    Duran, Jordi; Tevy, María Florencia; Garcia-Rocha, Mar; Calbó, Joaquim; Milán, Marco; Guinovart, Joan J

    2012-01-01

    Under physiological conditions, most neurons keep glycogen synthase (GS) in an inactive form and do not show detectable levels of glycogen. Nevertheless, aberrant glycogen accumulation in neurons is a hallmark of patients suffering from Lafora disease or other polyglucosan disorders. Although these diseases are associated with mutations in genes involved in glycogen metabolism, the role of glycogen accumulation remains elusive. Here, we generated mouse and fly models expressing an active form of GS to force neuronal accumulation of glycogen. We present evidence that the progressive accumulation of glycogen in mouse and Drosophila neurons leads to neuronal loss, locomotion defects and reduced lifespan. Our results highlight glycogen accumulation in neurons as a direct cause of neurodegeneration. PMID:22549942

  4. Paleogeographic controls of coal accumulation, Cretaceous Blackhawk Formation and Star Point Sandstone, Wasatch Plateau, Utah.

    USGS Publications Warehouse

    Flores, R.M.; Blanchard, L.F.; Sanchez, J.D.; Marley, W.E.; Muldoon, W.J.

    1984-01-01

    Considers the paleogeographic controls affecting the accumulation of coals in delta-barrier-island complexes. Progradation, lateral shifting, and abandonment of these complexes created four major landward-thinning tongues.-from Authors

  5. Experimental evidence of dietary ciguatoxin accumulation in an herbivorous coral reef fish.

    PubMed

    Clausing, Rachel J; Losen, Barbara; Oberhaensli, Francois R; Darius, H Taiana; Sibat, Manoella; Hess, Philipp; Swarzenski, Peter W; Chinain, Mireille; Dechraoui Bottein, Marie-Yasmine

    2018-07-01

    Ciguatoxins (CTXs) are potent algal toxins that cause widespread ciguatera poisoning and are found ubiquitously in coral reef food webs. Here we developed an environmentally-relevant, experimental model of CTX trophic transfer involving dietary exposure of herbivorous fish to the CTX-producing microalgae Gambierdiscus polynesiensis. Juvenile Naso brevirostris were fed a gel-food embedded with microalgae for 16 weeks (89 cells g -1 fish daily, 0.4 μg CTX3C equiv kg -1 fish). CTXs in muscle tissue were detectable after 2 weeks at levels above the threshold for human intoxication (1.2 ± 0.2 μg CTX3C equiv kg -1 ). Although tissue CTX concentrations stabilized after 8 weeks (∼3 ± 0.5 μg CTX3C equiv kg -1 ), muscle toxin burden (total μg CTX in muscle tissue) continued to increase linearly through the end of the experiment (16 weeks). Toxin accumulation was therefore continuous, yet masked by somatic growth dilution. The observed CTX concentrations, accumulation rates, and general absence of behavioural signs of intoxication are consistent with field observations and indicate that this method of dietary exposure may be used to develop predictive models of tissue-specific CTX uptake, metabolism and depuration. Results also imply that slow-growing fish may accumulate higher CTX flesh concentrations than fast-growing fish, which has important implications for global seafood safety. Copyright © 2018 Elsevier B.V. All rights reserved.

  6. Developing and using a rubric for evaluating evidence-based medicine point-of-care tools

    PubMed Central

    Foster, Margaret J

    2011-01-01

    Objective: The research sought to establish a rubric for evaluating evidence-based medicine (EBM) point-of-care tools in a health sciences library. Methods: The authors searched the literature for EBM tool evaluations and found that most previous reviews were designed to evaluate the ability of an EBM tool to answer a clinical question. The researchers' goal was to develop and complete rubrics for assessing these tools based on criteria for a general evaluation of tools (reviewing content, search options, quality control, and grading) and criteria for an evaluation of clinical summaries (searching tools for treatments of common diagnoses and evaluating summaries for quality control). Results: Differences between EBM tools' options, content coverage, and usability were minimal. However, the products' methods for locating and grading evidence varied widely in transparency and process. Conclusions: As EBM tools are constantly updating and evolving, evaluation of these tools needs to be conducted frequently. Standards for evaluating EBM tools need to be established, with one method being the use of objective rubrics. In addition, EBM tools need to provide more information about authorship, reviewers, methods for evidence collection, and grading system employed. PMID:21753917

  7. Developing and using a rubric for evaluating evidence-based medicine point-of-care tools.

    PubMed

    Shurtz, Suzanne; Foster, Margaret J

    2011-07-01

    The research sought to establish a rubric for evaluating evidence-based medicine (EBM) point-of-care tools in a health sciences library. The authors searched the literature for EBM tool evaluations and found that most previous reviews were designed to evaluate the ability of an EBM tool to answer a clinical question. The researchers' goal was to develop and complete rubrics for assessing these tools based on criteria for a general evaluation of tools (reviewing content, search options, quality control, and grading) and criteria for an evaluation of clinical summaries (searching tools for treatments of common diagnoses and evaluating summaries for quality control). Differences between EBM tools' options, content coverage, and usability were minimal. However, the products' methods for locating and grading evidence varied widely in transparency and process. As EBM tools are constantly updating and evolving, evaluation of these tools needs to be conducted frequently. Standards for evaluating EBM tools need to be established, with one method being the use of objective rubrics. In addition, EBM tools need to provide more information about authorship, reviewers, methods for evidence collection, and grading system employed.

  8. Ordinary differential equation for local accumulation time.

    PubMed

    Berezhkovskii, Alexander M

    2011-08-21

    Cell differentiation in a developing tissue is controlled by the concentration fields of signaling molecules called morphogens. Formation of these concentration fields can be described by the reaction-diffusion mechanism in which locally produced molecules diffuse through the patterned tissue and are degraded. The formation kinetics at a given point of the patterned tissue can be characterized by the local accumulation time, defined in terms of the local relaxation function. Here, we show that this time satisfies an ordinary differential equation. Using this equation one can straightforwardly determine the local accumulation time, i.e., without preliminary calculation of the relaxation function by solving the partial differential equation, as was done in previous studies. We derive this ordinary differential equation together with the accompanying boundary conditions and demonstrate that the earlier obtained results for the local accumulation time can be recovered by solving this equation. © 2011 American Institute of Physics

  9. Deleterious effects of neuronal accumulation of glycogen in flies and mice.

    PubMed

    Duran, Jordi; Tevy, María Florencia; Garcia-Rocha, Mar; Calbó, Joaquim; Milán, Marco; Guinovart, Joan J

    2012-08-01

    Under physiological conditions, most neurons keep glycogen synthase (GS) in an inactive form and do not show detectable levels of glycogen. Nevertheless, aberrant glycogen accumulation in neurons is a hallmark of patients suffering from Lafora disease or other polyglucosan disorders. Although these diseases are associated with mutations in genes involved in glycogen metabolism, the role of glycogen accumulation remains elusive. Here, we generated mouse and fly models expressing an active form of GS to force neuronal accumulation of glycogen. We present evidence that the progressive accumulation of glycogen in mouse and Drosophila neurons leads to neuronal loss, locomotion defects and reduced lifespan. Our results highlight glycogen accumulation in neurons as a direct cause of neurodegeneration. Copyright © 2012 EMBO Molecular Medicine.

  10. Is there evidence for a set point that regulates human body weight?

    PubMed

    Müller, Manfred J; Bosy-Westphal, Anja; Heymsfield, Steven B

    2010-08-09

    There is evidence for the idea that there is biological (active) control of body weight at a given set point. Body weight is the product of genetic effects (DNA), epigenetic effects (heritable traits that do not involve changes in DNA), and the environment. Regulation of body weight is asymmetric, being more effective in response to weight loss than to weight gain. However, regulation may be lost or camouflaged by Western diets, suggesting that the failure of biological control is due mainly to external factors. In this situation, the body's 'set point' (i.e., a constant 'body-inherent' weight regulated by a proportional feedback control system) is replaced by various 'settling points' that are influenced by energy and macronutrient intake in order for the body to achieve a zero energy balance. In a world of abundance, a prudent lifestyle and thus cognitive control are preconditions of effective biological control and a stable body weight. This idea also impacts future genetic research on body weight regulation. Searching for the genetic background of excess weight gain in a world of abundance is misleading since the possible biological control is widely overshadowed by the effect of the environment. In regard to clinical practice, dietary approaches to both weight loss and weight gain have to be reconsidered. In underweight patients (e.g., patients with anorexia nervosa), weight gain is supported by biological mechanisms that may or may not be suppressed by hyperalimentation. To overcome weight loss-induced counter-regulation in the overweight, biological signals have to be taken into account. Computational modeling of weight changes based on metabolic flux and its regulation will provide future strategies for clinical nutrition.

  11. Recurrent hamstring muscle injury: applying the limited evidence in the professional football setting with a seven-point programme

    PubMed Central

    Brukner, Peter; Nealon, Andrew; Morgan, Christopher; Burgess, Darren; Dunn, Andrew

    2014-01-01

    Recurrent hamstring injuries are a major problem in sports such as football. The aim of this paper was to use a clinical example to describe a treatment strategy for the management of recurrent hamstring injuries and examine the evidence for each intervention. A professional footballer sustained five hamstring injuries in a relatively short period of time. The injury was managed successfully with a seven-point programme—biomechanical assessment and correction, neurodynamics, core stability, eccentric strengthening, an overload running programme, injection therapies and stretching/relaxation. The evidence for each of these treatment options is reviewed. It is impossible to be definite about which aspects of the programme contributed to a successful outcome. Only limited evidence is available in most cases; therefore, decisions regarding the use of different treatment modalities must be made by using a combination of clinical experience and research evidence. PMID:23322894

  12. An Update on Accumulating Exercise and Postprandial Lipaemia: Translating Theory Into Practice

    PubMed Central

    Burns, Stephen F; Stensel, David J

    2013-01-01

    Over the last two decades, significant research attention has been given to the acute effect of a single bout of exercise on postprandial lipaemia. A large body of evidence supports the notion that an acute bout of aerobic exercise can reduce postprandial triacylglycerol (TAG) concentrations. However, this effect is short-lived emphasising the important role of regular physical activity for lowering TAG concentrations through an active lifestyle. In 1995, the concept of accumulating physical activity was introduced in expert recommendations with the advice that activity can be performed in several short bouts throughout the day with a minimum duration of 10 minutes per activity bout. Although the concept of accumulation has been widely publicised, there is still limited scientific evidence to support it but several studies have investigated the effects of accumulated activity on health-related outcomes to support the recommendations in physical activity guidelines. One area, which is the focus of this review, is the effect of accumulating exercise on postprandial lipaemia. We propose that accumulating exercise will provide additional physical activity options for lowering postprandial TAG concentrations relevant to individuals with limited time or exercise capacity to engage in more structured forms of exercise, or longer bouts of physical activity. The benefits of accumulated physical activity might translate to a reduced risk of cardiovascular disease in the long-term. PMID:23412842

  13. How Awareness Changes the Relative Weights of Evidence During Human Decision-Making

    PubMed Central

    Lamme, Victor A. F.; Dehaene, Stanislas

    2011-01-01

    Human decisions are based on accumulating evidence over time for different options. Here we ask a simple question: How is the accumulation of evidence affected by the level of awareness of the information? We examined the influence of awareness on decision-making using combined behavioral methods and magneto-encephalography (MEG). Participants were required to make decisions by accumulating evidence over a series of visually presented arrow stimuli whose visibility was modulated by masking. Behavioral results showed that participants could accumulate evidence under both high and low visibility. However, a top-down strategic modulation of the flow of incoming evidence was only present for stimuli with high visibility: once enough evidence had been accrued, participants strategically reduced the impact of new incoming stimuli. Also, decision-making speed and confidence were strongly modulated by the strength of the evidence for high-visible but not low-visible evidence, even though direct priming effects were identical for both types of stimuli. Neural recordings revealed that, while initial perceptual processing was independent of visibility, there was stronger top-down amplification for stimuli with high visibility than low visibility. Furthermore, neural markers of evidence accumulation over occipito-parietal cortex showed a strategic bias only for highly visible sensory information, speeding up processing and reducing neural computations related to the decision process. Our results indicate that the level of awareness of information changes decision-making: while accumulation of evidence already exists under low visibility conditions, high visibility allows evidence to be accumulated up to a higher level, leading to important strategical top-down changes in decision-making. Our results therefore suggest a potential role of awareness in deploying flexible strategies for biasing information acquisition in line with one's expectations and goals. PMID:22131904

  14. How awareness changes the relative weights of evidence during human decision-making.

    PubMed

    de Lange, Floris P; van Gaal, Simon; Lamme, Victor A F; Dehaene, Stanislas

    2011-11-01

    Human decisions are based on accumulating evidence over time for different options. Here we ask a simple question: How is the accumulation of evidence affected by the level of awareness of the information? We examined the influence of awareness on decision-making using combined behavioral methods and magneto-encephalography (MEG). Participants were required to make decisions by accumulating evidence over a series of visually presented arrow stimuli whose visibility was modulated by masking. Behavioral results showed that participants could accumulate evidence under both high and low visibility. However, a top-down strategic modulation of the flow of incoming evidence was only present for stimuli with high visibility: once enough evidence had been accrued, participants strategically reduced the impact of new incoming stimuli. Also, decision-making speed and confidence were strongly modulated by the strength of the evidence for high-visible but not low-visible evidence, even though direct priming effects were identical for both types of stimuli. Neural recordings revealed that, while initial perceptual processing was independent of visibility, there was stronger top-down amplification for stimuli with high visibility than low visibility. Furthermore, neural markers of evidence accumulation over occipito-parietal cortex showed a strategic bias only for highly visible sensory information, speeding up processing and reducing neural computations related to the decision process. Our results indicate that the level of awareness of information changes decision-making: while accumulation of evidence already exists under low visibility conditions, high visibility allows evidence to be accumulated up to a higher level, leading to important strategical top-down changes in decision-making. Our results therefore suggest a potential role of awareness in deploying flexible strategies for biasing information acquisition in line with one's expectations and goals.

  15. Intrinsic point-defect balance in self-ion-implanted ZnO.

    PubMed

    Neuvonen, Pekka T; Vines, Lasse; Svensson, Bengt G; Kuznetsov, Andrej Yu

    2013-01-04

    The role of excess intrinsic atoms for residual point defect balance has been discriminated by implanting Zn or O ions into Li-containing ZnO and monitoring Li redistribution and electrical resistivity after postimplant anneals. Strongly Li-depleted regions were detected in the Zn-implanted samples at depths beyond the projected range (R(p)) upon annealing ≥ 600 °C, correlating with a resistivity decrease. In contrast, similar anneals of the O-implanted samples resulted in Li accumulation at R(p) and an increased resistivity. Control samples implanted with Ar or Ne ions, yielding similar defect production as for the Zn or O implants but with no surplus of intrinsic atoms, revealed no Li depletion. Thus, the depletion of Li shows evidence of excess Zn interstitials (Zn(I)) being released during annealing of the Zn-implanted samples. These Zn(I)'s convert substitutional Li atoms (Li(Zn)) into highly mobile interstitial ones leading to the strongly Li-depleted regions. In the O-implanted samples, the high resistivity provides evidence of stable O(I)-related acceptors.

  16. Mercury accumulation and attenuation at a rapidly forming delta with a point source of mining waste

    PubMed Central

    Johnson, Bryce E.; Esser, Bradley K.; Whyte, Dyan C.; Ganguli, Priya M.; Austin, Carrie M.; Hunt, James R.

    2009-01-01

    The Walker Creek intertidal delta of Tomales Bay, California is impacted by a former mercury mine within the watershed. Eleven short sediment cores (10 cm length) collected from the delta found monomethylmercury (MMHg) concentrations ranging from 0.3 to 11.4 ng/g (dry wt.), with lower concentrations occurring at the vegetated marsh and upstream channel locations. Algal mats common to the delta’s sediment surface had MMHg concentrations ranging from 7.5 to 31.5 ng/g, and the top 1 cm of sediment directly under the mats had two times greater MMHg concentrations compared to adjacent locations without algal covering. Spatial trends in resident biota reflect enhanced MMHg uptake at the delta compared to other bay locations. Eighteen sediment cores, 1 to 2 meters deep, collected from the 1.2 km2 delta provide an estimate of a total mercury (Hg) inventory of 2500 ± 500 kg. Sediment Hg concentrations ranged from pre-mining background conditions of approximately 0.1 μg/g to a post-mining maximum of 5 μg/g. Sediment accumulation rates were determined from three sediment cores using measured differences of 137Cs activity. We estimate a pre-mining Hg accumulation of less than 20 kg/yr, and a period of maximum Hg accumulation in the 1970s and 1980s with loading rates greater than 50 kg/yr, corresponding to the failure of a tailings dam at the mine site. At the time of sampling (2003) over 40 kg/yr of Hg was still accumulating at the delta, indicating limited recovery. We attribute observed spatial evolution of elevated Hg levels to ongoing inputs and sediment re-working, and estimate the inventory of the anthropogenic fraction of total Hg to be at least 1500 ± 300 kg. We suggest ongoing sediment inputs and methylation at the deltaic surface support enhanced mercury levels for resident biota and transfer to higher trophic levels throughout the Bay. PMID:19539980

  17. Delay of gratification by orangutans (Pongo pygmaeus) in the accumulation task.

    PubMed

    Parrish, Audrey E; Perdue, Bonnie M; Stromberg, Erin E; Bania, Amanda E; Evans, Theodore A; Beran, Michael J

    2014-05-01

    There is considerable evidence indicating that chimpanzees can delay gratification for extended time intervals, particularly in the accumulation task in which food items accumulate within a participant's reach until the participant begins to consume them. However, there is limited evidence that other ape species might also exhibit this capacity, despite there being a number of similar studies indicating that nonape species (e.g., monkeys and birds) can delay gratification, but not for nearly as long as chimpanzees. To help define the taxonomic distribution of delay of gratification behavior in the order Primates, we tested 6 orangutans in the current experiments and compared their performance with comparable data from a previous study with capuchin monkeys. We varied delay length and visibility of the items that were still available for accumulation to determine the impact of these factors on performance. Species differences on the accumulation task emerged when comparing the current data to data from a previous study. Orangutans outperformed capuchin monkeys, suggesting that ape species may generally show better delay of gratification and delay maintenance abilities than monkeys. However, more studies are necessary to rule out alternative hypotheses on the distribution of delay maintenance abilities across primate species. ©2014 APA, all rights reserved.

  18. Characterization of ultra-fine grained aluminum produced by accumulative back extrusion (ABE)

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

    Alihosseini, H., E-mail: hamid.alihossieni@gmail.com; Materials Science and Engineering Department, Engineering School, Amirkabir University, Tehran; Faraji, G.

    2012-06-15

    In the present work, the microstructural evolutions and microhardness of AA1050 subjected to one, two and three passes of accumulative back extrusion (ABE) were investigated. The microstructural evolutions were characterized using transmission electron microscopy. The results revealed that applying three passes of accumulative back extrusion led to significant grain refinement. The initial grain size of 47 {mu}m was refined to the grains of 500 nm after three passes of ABE. Increasing the number of passes resulted in more decrease in grain size, better microstructure homogeneity and increase in the microhardness. The cross-section of ABEed specimen consisted of two different zones:more » (i) shear deformation zone, and (ii) normal deformation zone. The microhardness measurements indicated that the hardness increased from the initial value of 31 Hv to 67 Hv, verifying the significant microstructural refinement via accumulative back extrusion. - Highlights: Black-Right-Pointing-Pointer A significant grain refinement can be achieved in AA1050, Al alloy by applying ABE. Black-Right-Pointing-Pointer Microstructural homogeneity of ABEed samples increased by increasing the number of ABE cycles. Black-Right-Pointing-Pointer A substantial increase in the hardness, from 31 Hv to 67 Hv, was recorded.« less

  19. [Job crisis and transformations in the new model of accumulation].

    PubMed

    Zerda-Sarmiento, Alvaro

    2012-06-01

    The general and structural crisis capitalism is going through is the token of the difficulties accumulation model has been dealing with since 70's in developed countries. This model has been trying to settle down again on the basis of neoliberal principle and a new technical-economical paradigm. The new accumulation pattern has had a effect in employment sphere which have been made evident at all the elements that constitute work relationships. In Colombia, this model implementation has been partial and segmented. However, its consequences (and the long-term current crisis) have been evident in unemployment, precarious work, segmentation, informal work and restricted and private health insurance. Besides, financial accumulation makes labour profits flow at different levels. The economic model current government has aimed to implement leads to strengthening exports, so making population life conditions more difficult. In order to overcome the current state of affairs, the work sphere needs to become more creative. This creative approach should look for new schemes for expression and mobilization of work sphere's claims. This is supposed to be done by establishing a different economic model aimed to build a more inclusive future, with social justice.

  20. Role of brain iron accumulation in cognitive dysfunction: evidence from animal models and human studies.

    PubMed

    Schröder, Nadja; Figueiredo, Luciana Silva; de Lima, Maria Noêmia Martins

    2013-01-01

    Over the last decades, studies from our laboratory and other groups using animal models have shown that iron overload, resulting in iron accumulation in the brain, produces significant cognitive deficits. Iron accumulation in the hippocampus and the basal ganglia has been related to impairments in spatial memory, aversive memory, and recognition memory in rodents. These results are corroborated by studies showing that the administration of iron chelators attenuates cognitive deficits in a variety of animal models of cognitive dysfunction, including aging and Alzheimer's disease models. Remarkably, recent human studies using magnetic resonance image techniques have also shown a consistent correlation between cognitive dysfunction and iron deposition, mostly in the hippocampus, cortical areas, and basal ganglia. These findings may have relevant implications in the light of the knowledge that iron accumulates in brain regions of patients suffering from neurodegenerative diseases. A better understanding of the functional consequences of iron dysregulation in aging and neurological diseases may help to identify novel targets for treating memory problems that afflict a growing aging population.

  1. Postglacial sedimentary record of the Southern California continental shelf and slope, Point Conception to Dana Point

    USGS Publications Warehouse

    Sommerfield, C.K.; Lee, H.J.; Normark, W.R.

    2009-01-01

    Sedimentary strata on the Southern California shelf and slope (Point Conception to Dana Point) display patterns and rates of sediment accumulation that convey information on sea-level inundation, sediment supply, and oceanic transport processes following the Last Glacial Maximum. In Santa Monica Bay and San Pedro Bay, postglacial transgression is recorded in shelf deposits by wave-ravinement surfaces dated at 13-11 ka and an upsection transition from coastal to shallow-marine sediment facies. Depositional conditions analogous to the modern environment were established in the bays by 8-9 ka. On the continental slope, transgression is evidenced in places by an increase in sediment grain size and accumulation rate ca. 15-10 ka, a consequence of coastal ravinement and downslope resedimentation, perhaps in conjunction with climatic increases in fluvial sediment delivery. Grain sizes and accumulation rates then decreased after 12-10 ka when the shelf flooded and backfilled under rising sea level. The Santa Barbara coastal cell contains the largest mass of postglacial sediment at 32-42 ?? 109 metric tons, most of which occurs between offshore Santa Barbara and Hueneme Canyon. The San Pedro cell contains the second largest quantity of sediment, 8-11 ?? 109 metric tons, much of which is present on the eastern Palos Verdes and outer San Pedro shelves. By comparison, the mass of sediment sequestered within the Santa Monica cell is smaller at ??6-8 ?? 109 metric tons. The postglacial sediment mass distribution among coastal cells reflects the size of local fluvial sediment sources, whereas intracell accumulation patterns reflect antecedent bathymetric features conducive for sediment bypass or trapping. ?? 2009 The Geological Society of America.

  2. Keeping agricultural soil out of rivers: evidence of sediment and nutrient accumulation within field wetlands in the UK.

    PubMed

    Ockenden, Mary C; Deasy, Clare; Quinton, John N; Surridge, Ben; Stoate, Chris

    2014-03-15

    Intensification of agriculture has resulted in increased soil degradation and erosion, with associated pollution of surface waters. Small field wetlands, constructed along runoff pathways, offer one option for slowing down and storing runoff in order to allow more time for sedimentation and for nutrients to be taken up by plants or micro-organisms. This paper describes research to provide quantitative evidence for the effectiveness of small field wetlands in the UK landscape. Ten wetlands were built on four farms in Cumbria and Leicestershire, UK. Annual surveys of sediment and nutrient accumulation in 2010, 2011 and 2012 indicated that most sediment was trapped at a sandy site (70 tonnes over 3 years), compared to a silty site (40 tonnes over 3 years) and a clay site (2 tonnes over 3 years). The timing of rainfall was more important than total annual rainfall for sediment accumulation, with most sediment transported in a few intense rainfall events, especially when these coincided with bare soil or poor crop cover. Nutrient concentration within sediments was inversely related to median particle size, but the total mass of nutrients trapped was dependent on the total mass of sediment trapped. Ratios of nutrient elements in the wetland sediments were consistent between sites, despite different catchment characteristics across the individual wetlands. The nutrient value of sediment collected from the wetlands was similar to that of soil in the surrounding fields; dredged sediment was considered to have value as soil replacement but not as fertiliser. Overall, small field wetlands can make a valuable contribution to keeping soil out of rivers. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  3. Regulatory effects of curcumin on lipid accumulation in monocytes/macrophages

    USDA-ARS?s Scientific Manuscript database

    Recent evidence suggests potential benefits from phytochemicals and micronutrients in protecting against oxidative and lipid-mediated damage, but the molecular mechanisms of these actions are still unclear. Here we investigated whether the dietary polyphenol curcumin can modulate the accumulation of...

  4. Enhanced accumulation of adipocytes in bone marrow stromal cells in the presence of increased extracellular and intracellular [Ca{sup 2+}

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

    Hashimoto, Ryota, E-mail: hryota@juntendo.ac.jp; Katoh, Youichi, E-mail: katoyo@juntendo-urayasu.jp; Nakamura, Kyoko

    2012-07-13

    Highlights: Black-Right-Pointing-Pointer High [Ca{sup 2+}]{sub o} enhances adipocyte accumulation in the presence of adipogenic inducers. Black-Right-Pointing-Pointer High [Ca{sup 2+}]{sub o} enhances both proliferation and adipocyte differentiation in BMSCs. Black-Right-Pointing-Pointer High [Ca{sup 2+}]{sub o} induces an increase in [Ca{sup 2+}]{sub o} in BMSCs. Black-Right-Pointing-Pointer An intracellular Ca{sup 2+} chelator suppresses the enhancement in adipocyte accumulation. Black-Right-Pointing-Pointer Controlling [Ca{sup 2+}]{sub o} may govern the balance of adipocyte and osteoblast development. -- Abstract: The bone marrow stroma contains osteoblasts and adipocytes that have a common precursor: the pluripotent mesenchymal stem cell found in bone marrow stromal cells (BMSCs). Local bone marrow Ca{sup 2+}more » levels can reach high concentrations due to bone resorption, which is one of the notable features of the bone marrow stroma. Here, we describe the effects of high [Ca{sup 2+}]{sub o} on the accumulation of adipocytes in the bone marrow stroma. Using primary mouse BMSCs, we evaluated the level of adipocyte accumulation by measuring Oil Red O staining and glycerol-3-phosphate dehydrogenase (GPDH) activity. High [Ca{sup 2+}]{sub o} enhanced the accumulation of adipocytes following treatment with both insulin and dexamethasone together but not in the absence of this treatment. This enhanced accumulation was the result of both the accelerated proliferation of BMSCs and their differentiation into adipocytes. Using the fura-2 method, we also showed that high [Ca{sup 2+}]{sub o} induces an increase in [Ca{sup 2+}]{sub i}. An intracellular Ca{sup 2+} chelator suppressed the enhancement in adipocyte accumulation due to increased [Ca{sup 2+}]{sub o} in BMSCs. These data suggest a new role for extracellular Ca{sup 2+} in the bone marrow stroma: increased [Ca{sup 2+}]{sub o} induces an increase in [Ca{sup 2+}]{sub i} levels, which in turn enhances the

  5. The Cost of Accumulating Evidence in Perceptual Decision Making

    PubMed Central

    Drugowitsch, Jan; Moreno-Bote, Rubén; Churchland, Anne K.; Shadlen, Michael N.; Pouget, Alexandre

    2012-01-01

    Decision making often involves the accumulation of information over time, but acquiring information typically comes at a cost. Little is known about the cost incurred by animals and humans for acquiring additional information from sensory variables, due, for instance, to attentional efforts. Through a novel integration of diffusion models and dynamic programming, we were able to estimate the cost of making additional observations per unit of time from two monkeys and six humans in a reaction time random dot motion discrimination task. Surprisingly, we find that, the cost is neither zero nor constant over time, but for the animals and humans features a brief period in which it is constant but increases thereafter. In addition, we show that our theory accurately matches the observed reaction time distributions for each stimulus condition, the time-dependent choice accuracy both conditional on stimulus strength and independent of it, and choice accuracy and mean reaction times as a function of stimulus strength. The theory also correctly predicts that urgency signals in the brain should be independent of the difficulty, or stimulus strength, at each trial. PMID:22423085

  6. Computation of saddle point of attachment

    NASA Technical Reports Server (NTRS)

    Hung, Ching-Mao; Sung, Chao-Ho; Chen, Chung-Lung

    1991-01-01

    Low-speed flows over a cylinder mounted on a flat plate are studied numerically in order to confirm the existence of a saddle point of attachment in the flow before an obstacle, to analyze the flow characteristics near the saddle point theoretically, and to address the significance of the saddle point of attachment to the construction of external flow structures, the interpretation of experimental surface oil-flow patterns, and the theoretical definition of three-dimensional flow separation. Two numerical codes, one for an incompressible flow and another for a compressible flow, are used for various Mach numbers, Reynolds numbers, grid sizes, and numbers of grid points. It is pointed out that the potential presence of a saddle point of attachment means that a line of 'oil accumulation' from both sides of a skin-friction line emanating outward from a saddle point can be either a line of separation or a line of attachment.

  7. Accelerated Mutation Accumulation in Asexual Lineages of a Freshwater Snail

    PubMed Central

    Neiman, Maurine; Hehman, Gery; Miller, Joseph T.; Logsdon, John M.; Taylor, Douglas R.

    2010-01-01

    Sexual reproduction is both extremely costly and widespread relative to asexual reproduction, meaning that it must also confer profound advantages in order to persist. One theorized benefit of sex is that it facilitates the clearance of harmful mutations, which would accumulate more rapidly in the absence of recombination. The extent to which ineffective purifying selection and mutation accumulation are direct consequences of asexuality and whether the accelerated buildup of harmful mutations in asexuals can occur rapidly enough to maintain sex within natural populations, however, remain as open questions. We addressed key components of these questions by estimating the rate of mutation accumulation in the mitochondrial genomes of multiple sexual and asexual representatives of Potamopyrgus antipodarum, a New Zealand snail characterized by mixed sexual/asexual populations. We found that increased mutation accumulation is associated with asexuality and occurs rapidly enough to be detected in recently derived asexual lineages of P. antipodarum. Our results demonstrate that increased mutation accumulation in asexuals can differentially affect coexisting and ecologically similar sexual and asexual lineages. The accelerated rate of mutation accumulation observed in asexual P. antipodarum provides some of the most direct evidence to date for a link between asexuality and mutation accumulation and implies that mutational buildup could be rapid enough to contribute to the short-term evolutionary mechanisms that favor sexual reproduction. PMID:19995828

  8. Accumulation of Major Life Events in Childhood and Adult Life and Risk of Type 2 Diabetes Mellitus

    PubMed Central

    Masters Pedersen, Jolene; Hulvej Rod, Naja; Andersen, Ingelise; Lange, Theis; Poulsen, Gry; Prescott, Eva; Lund, Rikke

    2015-01-01

    Background The aim of the study was to estimate the effect of the accumulation of major life events (MLE) in childhood and adulthood, in both the private and working domains, on risk of type 2 diabetes mellitus (T2DM). Furthermore, we aimed to test the possible interaction between childhood and adult MLE and to investigate modification of these associations by educational attainment. Methods The study was based on 4,761 participants from the Copenhagen City Heart Study free of diabetes at baseline and followed for 10 years. MLE were categorized as 0, 1, 2, 3 or more events. Multivariate logistic regression models adjusted for age, sex, education and family history of diabetes were used to estimate the association between MLE and T2DM. Results In childhood, experiencing 3 or more MLE was associated with a 69% higher risk of developing T2DM (Odds Ratio (OR) 1.69; 95% Confidence Interval (CI) 1.60, 3.27). The accumulation of MLE in adult private (p-trend = 0.016) and work life (p-trend = 0.049) was associated with risk of T2DM in a dose response manner. There was no evidence that experiencing MLE in both childhood and adult life was more strongly associated with T2DM than experiencing events at only one time point. There was some evidence that being simultaneously exposed to childhood MLE and short education (OR 2.28; 95% C.I. 1.45, 3.59) and work MLE and short education (OR 2.86; 95% C.I. 1.62, 5.03) was associated with higher risk of T2DM, as the joint effects were greater than the sum of their individual effects. Conclusions Findings from this study suggest that the accumulation of MLE in childhood, private adult life and work life, respectively, are risk factors for developing T2DM. PMID:26394040

  9. Accumulate Repeat Accumulate Coded Modulation

    NASA Technical Reports Server (NTRS)

    Abbasfar, Aliazam; Divsalar, Dariush; Yao, Kung

    2004-01-01

    In this paper we propose an innovative coded modulation scheme called 'Accumulate Repeat Accumulate Coded Modulation' (ARA coded modulation). This class of codes can be viewed as serial turbo-like codes, or as a subclass of Low Density Parity Check (LDPC) codes that are combined with high level modulation. Thus at the decoder belief propagation can be used for iterative decoding of ARA coded modulation on a graph, provided a demapper transforms the received in-phase and quadrature samples to reliability of the bits.

  10. Repeated mass strandings of Miocene marine mammals from Atacama Region of Chile point to sudden death at sea.

    PubMed

    Pyenson, Nicholas D; Gutstein, Carolina S; Parham, James F; Le Roux, Jacobus P; Chavarría, Catalina Carreño; Little, Holly; Metallo, Adam; Rossi, Vincent; Valenzuela-Toro, Ana M; Velez-Juarbe, Jorge; Santelli, Cara M; Rogers, David Rubilar; Cozzuol, Mario A; Suárez, Mario E

    2014-04-22

    Marine mammal mass strandings have occurred for millions of years, but their origins defy singular explanations. Beyond human causes, mass strandings have been attributed to herding behaviour, large-scale oceanographic fronts and harmful algal blooms (HABs). Because algal toxins cause organ failure in marine mammals, HABs are the most common mass stranding agent with broad geographical and widespread taxonomic impact. Toxin-mediated mortalities in marine food webs have the potential to occur over geological timescales, but direct evidence for their antiquity has been lacking. Here, we describe an unusually dense accumulation of fossil marine vertebrates from Cerro Ballena, a Late Miocene locality in Atacama Region of Chile, preserving over 40 skeletons of rorqual whales, sperm whales, seals, aquatic sloths, walrus-whales and predatory bony fish. Marine mammal skeletons are distributed in four discrete horizons at the site, representing a recurring accumulation mechanism. Taphonomic analysis points to strong spatial focusing with a rapid death mechanism at sea, before being buried on a barrier-protected supratidal flat. In modern settings, HABs are the only known natural cause for such repeated, multispecies accumulations. This proposed agent suggests that upwelling zones elsewhere in the world should preserve fossil marine vertebrate accumulations in similar modes and densities.

  11. Repeated mass strandings of Miocene marine mammals from Atacama Region of Chile point to sudden death at sea

    PubMed Central

    Pyenson, Nicholas D.; Gutstein, Carolina S.; Parham, James F.; Le Roux, Jacobus P.; Chavarría, Catalina Carreño; Little, Holly; Metallo, Adam; Rossi, Vincent; Valenzuela-Toro, Ana M.; Velez-Juarbe, Jorge; Santelli, Cara M.; Rogers, David Rubilar; Cozzuol, Mario A.; Suárez, Mario E.

    2014-01-01

    Marine mammal mass strandings have occurred for millions of years, but their origins defy singular explanations. Beyond human causes, mass strandings have been attributed to herding behaviour, large-scale oceanographic fronts and harmful algal blooms (HABs). Because algal toxins cause organ failure in marine mammals, HABs are the most common mass stranding agent with broad geographical and widespread taxonomic impact. Toxin-mediated mortalities in marine food webs have the potential to occur over geological timescales, but direct evidence for their antiquity has been lacking. Here, we describe an unusually dense accumulation of fossil marine vertebrates from Cerro Ballena, a Late Miocene locality in Atacama Region of Chile, preserving over 40 skeletons of rorqual whales, sperm whales, seals, aquatic sloths, walrus-whales and predatory bony fish. Marine mammal skeletons are distributed in four discrete horizons at the site, representing a recurring accumulation mechanism. Taphonomic analysis points to strong spatial focusing with a rapid death mechanism at sea, before being buried on a barrier-protected supratidal flat. In modern settings, HABs are the only known natural cause for such repeated, multispecies accumulations. This proposed agent suggests that upwelling zones elsewhere in the world should preserve fossil marine vertebrate accumulations in similar modes and densities. PMID:24573855

  12. Point Barrow, Alaska

    NASA Image and Video Library

    2015-09-10

    Point Barrow or Nuvuk, Alaska is the northernmost point of all territory of the United States. It also marks the limit between the Chukchi Sea to the west, and the Beaufort Sea to the east. Archaeological evidence indicates that Point Barrow was occupied about 500 CE, probably as hunting camps for whales. The image covers an area of 32 by 38 km, was acquired July 29, 2015, and is located at 71.6 degrees north, 156.45 degrees west. http://photojournal.jpl.nasa.gov/catalog/PIA19775

  13. First evidence of an extensive Acheulean large cutting tool accumulation in Europe from Porto Maior (Galicia, Spain).

    PubMed

    Méndez-Quintas, E; Santonja, M; Pérez-González, A; Duval, M; Demuro, M; Arnold, L J

    2018-02-15

    We describe a European Acheulean site characterised by an extensive accumulation of large cutting tools (LCT). This type of Lower Paleolithic assemblage, with dense LCT accumulations, has only been found on the African continent and in the Near East until now. The identification of a site with large accumulations of LCTs favours the hypothesis of an African origin for the Acheulean of Southwest Europe. The lithic tool-bearing deposits date back to 293-205 thousand years ago. Our chronological findings confirm temporal overlap between sites with clear "African" Acheulean affinities and Early Middle Paleolithic sites found elsewhere in the region. These complex technological patterns could be consistent with the potential coexistence of different human species in south-western Europe during the Middle Pleistocene.

  14. Step changes in leaf oil accumulation via iterative metabolic engineering.

    PubMed

    Vanhercke, Thomas; Divi, Uday K; El Tahchy, Anna; Liu, Qing; Mitchell, Madeline; Taylor, Matthew C; Eastmond, Peter J; Bryant, Fiona; Mechanicos, Anna; Blundell, Cheryl; Zhi, Yao; Belide, Srinivas; Shrestha, Pushkar; Zhou, Xue-Rong; Ral, Jean-Philippe; White, Rosemary G; Green, Allan; Singh, Surinder P; Petrie, James R

    2017-01-01

    Synthesis and accumulation of plant oils in the entire vegetative biomass offers the potential to deliver yields surpassing those of oilseed crops. However, current levels still fall well short of those typically found in oilseeds. Here we show how transcriptome and biochemical analyses pointed to a futile cycle in a previously established Nicotiana tabacum line, accumulating up to 15% (dry weight) of the storage lipid triacylglycerol in leaf tissue. To overcome this metabolic bottleneck, we either silenced the SDP1 lipase or overexpressed the Arabidopsis thaliana LEC2 transcription factor in this transgenic background. Both strategies independently resulted in the accumulation of 30-33% triacylglycerol in leaf tissues. Our results demonstrate that the combined optimization of de novo fatty acid biosynthesis, storage lipid assembly and lipid turnover in leaf tissue results in a major overhaul of the plant central carbon allocation and lipid metabolism. The resulting further step changes in oil accumulation in the entire plant biomass offers the possibility of delivering yields that outperform current oilseed crops. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  15. Disease-associated protein seeding suggests a dissociation between misfolded protein accumulation and neurodegeneration in prion disease

    PubMed Central

    Alibhai, James; Diack, Abigail; Manson, Jean

    2017-01-01

    ABSTRACT Chronic neurodegenerative diseases, such as prion diseases or Alzheimer's disease, are associated with progressive accumulation of host proteins which misfold and aggregate. Neurodegeneration is restricted to specific neuronal populations which show clear accumulation of misfolded proteins, whilst neighbouring neurons remain unaffected. Such data raise interesting questions about the vulnerability of specific neuronal populations to neurodegeneration and much research has concentrated only on the mechanisms of neurodegeneration in afflicted neuronal populations. An alternative, undervalued and almost completely unstudied question however is how and why neuronal populations are resilient to neurodegeneration. One potential answer is unaffected regions do not accumulate misfolded proteins, thus mechanisms of neurodegeneration do not become activated. In this perspectives, we discuss novel data from our laboratories which demonstrate that misfolded proteins do accumulate in regions of the brain which do not show evidence of neurodegeneration and further evidence that microglial responses may define the severity of neurodegeneration. PMID:29023184

  16. Five-month-old infants have expectations for the accumulation of nonsolid substances.

    PubMed

    Anderson, Erin M; Hespos, Susan J; Rips, Lance J

    2018-06-01

    Infants fail to represent quantities of non-cohesive substances in paradigms where they succeed with solid objects. Some investigators have interpreted these results as evidence that infants do not yet have representations for substances. More recent research, however, shows that 5-month-old infants expect objects and substances to behave and interact in different ways. In the present experiments, we test whether infants have expectations for substances when the outcomes are not simply the opposite of those for objects. In Experiment 1, we find that 5-month-old infants expect that when a cup of sand pours behind a screen, it will accumulate in just one pile rather than two. Similarly, infants expect that when two cups of sand pour in separate streams, two distinct piles will accumulate rather than one. Infants look significantly longer at outcomes with an inconsistent number of piles, providing evidence that infants have expectations for how sand accumulates. To test whether the number of cups or the number of pours guided expectations about accumulation, Experiment 2 placed these cues in conflict. This resulted in chance performance, suggesting that, for infants to build expectations about these outcomes, they need both cues (cup and pour) to converge. These findings offer insight into the nature of infants' representations for non-cohesive substances like sand. Copyright © 2018 Elsevier B.V. All rights reserved.

  17. Anthocyanins facilitate tungsten accumulation in Brassica

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

    Hale, K.L.

    2002-11-01

    Accumulation of molybdenum in Brassica was recently found to be correlated with anthocyanin content, involving the formation of a blue complex. Here the role of anthocyanins in tungsten sequestration was investigated using three species of Brassica: B. rapa (cv. Fast plants), B. juncea (Indian mustard) and B. oleracea (red cabbage). Seedlings of B. rapa and B. juncea turned blue when supplied with colourless tungstate. The blue compound co-localized with anthocyanins in the peripheral cell layers, and the degree of blueness was correlated with anthocyanin content. The direct involvement of anthocyanins in the blue coloration was evident when purified anthocyanins showedmore » a colour change from pink to blue in vitro upon addition of tungstate, over a wide pH range. Anthocyanin production was upregulated 3-fold by W in B. juncea, possibly reflecting a function for anthocyanins in W tolerance or sequestration. The presence of anthocyanins facilitated W accumulation in B. rapa: anthocyanin-containing seedlings accumulated 3-fold more W than an anthocyaninless mutant. There was no correlation between anthocyanin content and W tolerance under these conditions. The nature of the interaction between anthocyanins and tungstate was investigated. X-ray absorption spectroscopy showed no change in the local chemical environment of Wupon uptake of tungstate by the plant; HPLC analysis of purified anthocyanin with or without tungstate showed no peak shift after metal treatment.« less

  18. Annual accumulation over the Greenland ice sheet interpolated from historical and newly compiled observation data

    USGS Publications Warehouse

    Shen, Dayong; Liu, Yuling; Huang, Shengli

    2012-01-01

    The estimation of ice/snow accumulation is of great significance in quantifying the mass balance of ice sheets and variation in water resources. Improving the accuracy and reducing uncertainty has been a challenge for the estimation of annual accumulation over the Greenland ice sheet. In this study, we kriged and analyzed the spatial pattern of accumulation based on an observation data series including 315 points used in a recent research, plus 101 ice cores and snow pits and newly compiled 23 coastal weather station data. The estimated annual accumulation over the Greenland ice sheet is 31.2 g cm−2 yr−1, with a standard error of 0.9 g cm−2 yr−1. The main differences between the improved map developed in this study and the recently published accumulation maps are in the coastal areas, especially southeast and southwest regions. The analysis of accumulations versus elevation reveals the distribution patterns of accumulation over the Greenland ice sheet.

  19. Strain accumulation and rotation in the Eastern California Shear Zone

    USGS Publications Warehouse

    Savage, J.C.; Gan, Weijun; Svarc, J.L.

    2001-01-01

    Although the Eastern California Shear Zone (ECSZ) (strike ???N25??W) does not quite coincide with a small circle drawn about the Pacific-North America pole of rotation, trilateration and GPS measurements demonstrate that the motion within the zone corresponds to right-lateral simple shear across a vertical plane (strike N33??W??5??) roughly parallel to the tangent to that local small circle (strike ???N40??W). If the simple shear is released by slip on faults subparallel to the shear zone, the accumulated rotation is also released, leaving no secular rotation. South of the Garlock fault the principal faults (e.g., Calico-Blackwater fault) strike ???N40??W, close enough to the strike of the vertical plane across which maximum right-lateral shear accumulates to almost wholly accommodate that accumulation of both strain and rotation by right-lateral slip. North of the Garlock fault dip slip as well as strike slip on the principal faults (strike ???N20??W) is required to accommodate the simple shear accumulation. In both cases the accumulated rotation is released with the shear strain. The Garlock fault, which transects the ECSZ, is not offset by north-northwest striking faults nor, despite geological evidence for long-term left-lateral slip, does it appear at the present time to be accumulating left-lateral simple shear strain across the fault due to slip at depth. Rather the motion is explained by right-lateral simple shear across the orthogonal ECSZ. Left-lateral slip on the Garlock fault will release the shear strain accumulating there but would augment the accumulating rotation, resulting in a secular clockwise rotation rate ???80 nrad yr-1 (4.6?? Myr-1).

  20. Pulmonary accumulation of polymorphonuclear leukocytes in the adult respiratory distress syndrome

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

    Powe, J.E.; Short, A.; Sibbald, W.J.

    1982-11-01

    The polymorphonuclear leukocyte (PMN) plays an integral role in the development of permeability pulmonary edema associated with the adult respiratory distress syndrome (ARDS). This report describes 3 patients with ARDS secondary to systemic sepsis who demonstrated an abnormal diffuse accumulation of Indium (/sup 111/In)-labeled PMNs in their lungs, without concomitant clinical or laboratory evidence of a primary chest infection. In one patient, the accumulation of the pulmonary activity during an initial pass suggested that this observation was related to diffuse leukoaggregation within the pulmonary microvasculature. A 4th patient with ARDS was on high-dose corticosteroids at the time of a similarmore » study, and showed no pulmonary accumulation of PMNs, suggesting a possible reason for the reported beneficial effect of corticosteroids in human ARDS.« less

  1. Bayes factors for the linear ballistic accumulator model of decision-making.

    PubMed

    Evans, Nathan J; Brown, Scott D

    2018-04-01

    Evidence accumulation models of decision-making have led to advances in several different areas of psychology. These models provide a way to integrate response time and accuracy data, and to describe performance in terms of latent cognitive processes. Testing important psychological hypotheses using cognitive models requires a method to make inferences about different versions of the models which assume different parameters to cause observed effects. The task of model-based inference using noisy data is difficult, and has proven especially problematic with current model selection methods based on parameter estimation. We provide a method for computing Bayes factors through Monte-Carlo integration for the linear ballistic accumulator (LBA; Brown and Heathcote, 2008), a widely used evidence accumulation model. Bayes factors are used frequently for inference with simpler statistical models, and they do not require parameter estimation. In order to overcome the computational burden of estimating Bayes factors via brute force integration, we exploit general purpose graphical processing units; we provide free code for this. This approach allows estimation of Bayes factors via Monte-Carlo integration within a practical time frame. We demonstrate the method using both simulated and real data. We investigate the stability of the Monte-Carlo approximation, and the LBA's inferential properties, in simulation studies.

  2. Term Cancellations in Computing Floating-Point Gröbner Bases

    NASA Astrophysics Data System (ADS)

    Sasaki, Tateaki; Kako, Fujio

    We discuss the term cancellation which makes the floating-point Gröbner basis computation unstable, and show that error accumulation is never negligible in our previous method. Then, we present a new method, which removes accumulated errors as far as possible by reducing matrices constructed from coefficient vectors by the Gaussian elimination. The method manifests amounts of term cancellations caused by the existence of approximate linearly dependent relations among input polynomials.

  3. Molecular chaperone accumulation as a function of stress evidences adaptation to high hydrostatic pressure in the piezophilic archaeon Thermococcus barophilus.

    PubMed

    Cario, Anaïs; Jebbar, Mohamed; Thiel, Axel; Kervarec, Nelly; Oger, Phil M

    2016-07-05

    The accumulation of mannosyl-glycerate (MG), the salinity stress response osmolyte of Thermococcales, was investigated as a function of hydrostatic pressure in Thermococcus barophilus strain MP, a hyperthermophilic, piezophilic archaeon isolated from the Snake Pit site (MAR), which grows optimally at 40 MPa. Strain MP accumulated MG primarily in response to salinity stress, but in contrast to other Thermococcales, MG was also accumulated in response to thermal stress. MG accumulation peaked for combined stresses. The accumulation of MG was drastically increased under sub-optimal hydrostatic pressure conditions, demonstrating that low pressure is perceived as a stress in this piezophile, and that the proteome of T. barophilus is low-pressure sensitive. MG accumulation was strongly reduced under supra-optimal pressure conditions clearly demonstrating the structural adaptation of this proteome to high hydrostatic pressure. The lack of MG synthesis only slightly altered the growth characteristics of two different MG synthesis deletion mutants. No shift to other osmolytes was observed. Altogether our observations suggest that the salinity stress response in T. barophilus is not essential and may be under negative selective pressure, similarly to what has been observed for its thermal stress response.

  4. Molecular chaperone accumulation as a function of stress evidences adaptation to high hydrostatic pressure in the piezophilic archaeon Thermococcus barophilus

    PubMed Central

    Cario, Anaïs; Jebbar, Mohamed; Thiel, Axel; Kervarec, Nelly; Oger, Phil M.

    2016-01-01

    The accumulation of mannosyl-glycerate (MG), the salinity stress response osmolyte of Thermococcales, was investigated as a function of hydrostatic pressure in Thermococcus barophilus strain MP, a hyperthermophilic, piezophilic archaeon isolated from the Snake Pit site (MAR), which grows optimally at 40 MPa. Strain MP accumulated MG primarily in response to salinity stress, but in contrast to other Thermococcales, MG was also accumulated in response to thermal stress. MG accumulation peaked for combined stresses. The accumulation of MG was drastically increased under sub-optimal hydrostatic pressure conditions, demonstrating that low pressure is perceived as a stress in this piezophile, and that the proteome of T. barophilus is low-pressure sensitive. MG accumulation was strongly reduced under supra-optimal pressure conditions clearly demonstrating the structural adaptation of this proteome to high hydrostatic pressure. The lack of MG synthesis only slightly altered the growth characteristics of two different MG synthesis deletion mutants. No shift to other osmolytes was observed. Altogether our observations suggest that the salinity stress response in T. barophilus is not essential and may be under negative selective pressure, similarly to what has been observed for its thermal stress response. PMID:27378270

  5. Modeling Biota-Sediment Accumulation Factors in fish for AOC habitat restoration projects

    EPA Science Inventory

    We compiled contaminated sediment data for Dioxins and Dioxin Like PCBs for the St. Louis River Area of Concern as part of a health impact assessment for the proposed Kingsbury Bay Grassy Point Habitat Restoration project. To incorporate potential Biota-Sediment Accumulation Fac...

  6. A large accumulation of avian eggs from the late cretaceous of patagonia (Argentina) reveals a novel nesting strategy in mesozoic birds.

    PubMed

    Fernández, Mariela S; García, Rodolfo A; Fiorelli, Lucas; Scolaro, Alejandro; Salvador, Rodrigo B; Cotaro, Carlos N; Kaiser, Gary W; Dyke, Gareth J

    2013-01-01

    We report the first evidence for a nesting colony of mesozoic birds on Gondwana: a fossil accumulation in Late Cretaceous rocks mapped and collected from within the campus of the National University of Comahue, Neuquén City, Patagonia (Argentina). Here, Cretaceous ornithothoracine birds, almost certainly Enanthiornithes, nested in an arid, shallow basinal environment among sand dunes close to an ephemeral water-course. We mapped and collected 65 complete, near-complete, and broken eggs across an area of more than 55 m(2). These eggs were laid either singly, or occasionally in pairs, onto a sandy substrate. All eggs were found apparently in, or close to, their original nest site; they all occur within the same bedding plane and may represent the product of a single nesting season or a short series of nesting attempts. Although there is no evidence for nesting structures, all but one of the Comahue eggs were half-buried upright in the sand with their pointed end downwards, a position that would have exposed the pole containing the air cell and precluded egg turning. This egg position is not seen in living birds, with the exception of the basal galliform megapodes who place their eggs within mounds of vegetation or burrows. This accumulation reveals a novel nesting behaviour in Mesozoic Aves that was perhaps shared with the non-avian and phylogenetically more basal troodontid theropods.

  7. A Large Accumulation of Avian Eggs from the Late Cretaceous of Patagonia (Argentina) Reveals a Novel Nesting Strategy in Mesozoic Birds

    PubMed Central

    Fernández, Mariela S.; García, Rodolfo A.; Fiorelli, Lucas; Scolaro, Alejandro; Salvador, Rodrigo B.; Cotaro, Carlos N.; Kaiser, Gary W.; Dyke, Gareth J.

    2013-01-01

    We report the first evidence for a nesting colony of Mesozoic birds on Gondwana: a fossil accumulation in Late Cretaceous rocks mapped and collected from within the campus of the National University of Comahue, Neuquén City, Patagonia (Argentina). Here, Cretaceous ornithothoracine birds, almost certainly Enanthiornithes, nested in an arid, shallow basinal environment among sand dunes close to an ephemeral water-course. We mapped and collected 65 complete, near-complete, and broken eggs across an area of more than 55 m2. These eggs were laid either singly, or occasionally in pairs, onto a sandy substrate. All eggs were found apparently in, or close to, their original nest site; they all occur within the same bedding plane and may represent the product of a single nesting season or a short series of nesting attempts. Although there is no evidence for nesting structures, all but one of the Comahue eggs were half-buried upright in the sand with their pointed end downwards, a position that would have exposed the pole containing the air cell and precluded egg turning. This egg position is not seen in living birds, with the exception of the basal galliform megapodes who place their eggs within mounds of vegetation or burrows. This accumulation reveals a novel nesting behaviour in Mesozoic Aves that was perhaps shared with the non-avian and phylogenetically more basal troodontid theropods. PMID:23613776

  8. Evidence of common and separate eye and hand accumulators underlying flexible eye-hand coordination

    PubMed Central

    Jana, Sumitash; Gopal, Atul

    2016-01-01

    Eye and hand movements are initiated by anatomically separate regions in the brain, and yet these movements can be flexibly coupled and decoupled, depending on the need. The computational architecture that enables this flexible coupling of independent effectors is not understood. Here, we studied the computational architecture that enables flexible eye-hand coordination using a drift diffusion framework, which predicts that the variability of the reaction time (RT) distribution scales with its mean. We show that a common stochastic accumulator to threshold, followed by a noisy effector-dependent delay, explains eye-hand RT distributions and their correlation in a visual search task that required decision-making, while an interactive eye and hand accumulator model did not. In contrast, in an eye-hand dual task, an interactive model better predicted the observed correlations and RT distributions than a common accumulator model. Notably, these two models could only be distinguished on the basis of the variability and not the means of the predicted RT distributions. Additionally, signatures of separate initiation signals were also observed in a small fraction of trials in the visual search task, implying that these distinct computational architectures were not a manifestation of the task design per se. Taken together, our results suggest two unique computational architectures for eye-hand coordination, with task context biasing the brain toward instantiating one of the two architectures. NEW & NOTEWORTHY Previous studies on eye-hand coordination have considered mainly the means of eye and hand reaction time (RT) distributions. Here, we leverage the approximately linear relationship between the mean and standard deviation of RT distributions, as predicted by the drift-diffusion model, to propose the existence of two distinct computational architectures underlying coordinated eye-hand movements. These architectures, for the first time, provide a computational basis for

  9. Size, Accumulation and Performance for Research Grants: Examining the Role of Size for Centres of Excellence

    PubMed Central

    Bloch, Carter; Schneider, Jesper W.; Sinkjær, Thomas

    2016-01-01

    The present paper examines the relation between size, accumulation and performance for research grants, where we examine the relation between grant size for Centres of Excellence (CoE) funded by the Danish National Research Foundation (DNRF) and various ex post research performance measures, including impact and shares of highly cited articles. We examine both the relation between size and performance and also how performance for CoEs evolves over the course of grant periods. In terms of dynamics, it appears that performance over the grant period (i.e. 10 years) is falling for the largest CoEs, while it is increasing for those among the smallest half. Overall, multivariate econometric analysis finds evidence that performance is increasing in grant size and over time. In both cases, the relation appears to be non-linear, suggesting that there is a point at which performance peaks. The CoEs have also been very successful in securing additional funding, which can be viewed as a ‘cumulative effect’ of center grants. In terms of new personnel, the far majority of additional funding is spent on early career researchers, hence, this accumulation would appear to have a ‘generational’ dimension, allowing for scientific expertise to be passed on to an increasing number of younger researchers. PMID:26862907

  10. Conifer ovulate cones accumulate pollen principally by simple impaction.

    PubMed

    Cresswell, James E; Henning, Kevin; Pennel, Christophe; Lahoubi, Mohamed; Patrick, Michael A; Young, Phillipe G; Tabor, Gavin R

    2007-11-13

    In many pine species (Family Pinaceae), ovulate cones structurally resemble a turbine, which has been widely interpreted as an adaptation for improving pollination by producing complex aerodynamic effects. We tested the turbine interpretation by quantifying patterns of pollen accumulation on ovulate cones in a wind tunnel and by using simulation models based on computational fluid dynamics. We used computer-aided design and computed tomography to create computational fluid dynamics model cones. We studied three species: Pinus radiata, Pinus sylvestris, and Cedrus libani. Irrespective of the approach or species studied, we found no evidence that turbine-like aerodynamics made a significant contribution to pollen accumulation, which instead occurred primarily by simple impaction. Consequently, we suggest alternative adaptive interpretations for the structure of ovulate cones.

  11. Conifer ovulate cones accumulate pollen principally by simple impaction

    PubMed Central

    Cresswell, James E.; Henning, Kevin; Pennel, Christophe; Lahoubi, Mohamed; Patrick, Michael A.; Young, Phillipe G.; Tabor, Gavin R.

    2007-01-01

    In many pine species (Family Pinaceae), ovulate cones structurally resemble a turbine, which has been widely interpreted as an adaptation for improving pollination by producing complex aerodynamic effects. We tested the turbine interpretation by quantifying patterns of pollen accumulation on ovulate cones in a wind tunnel and by using simulation models based on computational fluid dynamics. We used computer-aided design and computed tomography to create computational fluid dynamics model cones. We studied three species: Pinus radiata, Pinus sylvestris, and Cedrus libani. Irrespective of the approach or species studied, we found no evidence that turbine-like aerodynamics made a significant contribution to pollen accumulation, which instead occurred primarily by simple impaction. Consequently, we suggest alternative adaptive interpretations for the structure of ovulate cones. PMID:17986613

  12. [Genetic Mutation Accumulation and Clinical Outcome of Immune Checkpoint Blockade Therapy].

    PubMed

    Takahashi, Masanobu

    2016-06-01

    Immune checkpoint blockade therapy has recently attracted great attention in the area of oncology. In Japan, since 2014, an anti-PD-1 antibody nivolumab and anti-CTLA-4 antibody ipilimumab have been available for the treatment of patients with malignant melanoma, and nivolumab has been available for patients with non-small cell lung cancer. Clinical trials using these drugs and other immune checkpoint inhibitors are currently in progress worldwide. The immune checkpoint blockade therapy is a promising new cancer therapy; however, not all patients with cancer can benefit from this therapy. Recent evidence shows that markers reflecting the extent of genetic mutation accumulation, including mutation burden, non-synonymous mutation that produces neoantigen, and microsatellite instability, possibly serve as promising marker to predict who can benefit from the immune checkpoint blockade therapy. Here, I introduce the recent evidence and discuss the correlation between genetic mutation accumulation and clinical outcome of immune checkpoint blockade therapy.

  13. The Physics of Decision Making:. Stochastic Differential Equations as Models for Neural Dynamics and Evidence Accumulation in Cortical Circuits

    NASA Astrophysics Data System (ADS)

    Holmes, Philip; Eckhoff, Philip; Wong-Lin, K. F.; Bogacz, Rafal; Zacksenhouse, Miriam; Cohen, Jonathan D.

    2010-03-01

    We describe how drift-diffusion (DD) processes - systems familiar in physics - can be used to model evidence accumulation and decision-making in two-alternative, forced choice tasks. We sketch the derivation of these stochastic differential equations from biophysically-detailed models of spiking neurons. DD processes are also continuum limits of the sequential probability ratio test and are therefore optimal in the sense that they deliver decisions of specified accuracy in the shortest possible time. This leaves open the critical balance of accuracy and speed. Using the DD model, we derive a speed-accuracy tradeoff that optimizes reward rate for a simple perceptual decision task, compare human performance with this benchmark, and discuss possible reasons for prevalent sub-optimality, focussing on the question of uncertain estimates of key parameters. We present an alternative theory of robust decisions that allows for uncertainty, and show that its predictions provide better fits to experimental data than a more prevalent account that emphasises a commitment to accuracy. The article illustrates how mathematical models can illuminate the neural basis of cognitive processes.

  14. WRNIP1 accumulates at laser light irradiated sites rapidly via its ubiquitin-binding zinc finger domain and independently from its ATPase domain

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

    Nomura, Hironoshin; Yoshimura, Akari, E-mail: akari_yo@musashino-u.ac.jp; Edo, Takato

    2012-01-27

    Highlights: Black-Right-Pointing-Pointer WRNIP1 accumulates in laser light irradiated sites very rapidly via UBZ domain. Black-Right-Pointing-Pointer The ATPase domain of WRNIP1 is dispensable for its accumulation. Black-Right-Pointing-Pointer The accumulation of WRNIP1 seems not to be dependent on the interaction with WRN. -- Abstract: WRNIP1 (Werner helicase-interacting protein 1) was originally identified as a protein that interacts with the Werner syndrome responsible gene product. WRNIP1 contains a ubiquitin-binding zinc-finger (UBZ) domain in the N-terminal region and two leucine zipper motifs in the C-terminal region. In addition, it possesses an ATPase domain in the middle of the molecule and the lysine residues servingmore » as ubiquitin acceptors in the entire of the molecule. Here, we report that WRNIP1 accumulates in laser light irradiated sites very rapidly via its ubiquitin-binding zinc finger domain, which is known to bind polyubiquitin and to be involved in ubiquitination of WRNIP1 itself. The accumulation of WRNIP1 in laser light irradiated sites also required the C-terminal region containing two leucine zippers, which is reportedly involved in the oligomerization of WRNIP1. Mutated WRNIP1 with a deleted ATPase domain or with mutations in lysine residues, which serve as ubiquitin acceptors, accumulated in laser light irradiated sites, suggesting that the ATPase domain of WRNIP1 and ubiquitination of WRNIP1 are dispensable for the accumulation.« less

  15. Marine debris accumulation in the Northwestern Hawaiian Islands: an examination of rates and processes.

    PubMed

    Dameron, Oliver J; Parke, Michael; Albins, Mark A; Brainard, Russell

    2007-04-01

    Large amounts of derelict fishing gear accumulate and cause damage to shallow coral reefs of the Northwestern Hawaiian Islands (NWHI). To facilitate maintenance of reefs cleaned during 1996-2005 removal efforts, we identify likely high-density debris areas by assessing reef characteristics (depth, benthic habitat type, and energy regime) that influence sub-regional debris accumulation. Previously cleaned backreef and lagoonal reefs at two NWHI locations were resurveyed for accumulated debris using two survey methods. Accumulated debris densities and weights were found to be greater in lagoonal reef areas. Sample weight-based debris densities are extrapolated to similar habitats throughout the NWHI using a spatial 'net habitat' dataset created by generalizing IKONOS satellite derivatives for depth and habitat classification. Prediction accuracy for this dataset is tested using historical debris point data. Annual NWHI debris accumulation is estimated to be 52.0 metric tonnes. For planning purposes, individual NWHI atolls/reefs are allotted a proportion of this total.

  16. Closing the evidence gap in infectious disease: point-of-care randomization and informed consent.

    PubMed

    Huttner, A; Leibovici, L; Theuretzbacher, U; Huttner, B; Paul, M

    2017-02-01

    The informed consent document is intended to provide basic rights to patients but often fails to do so. Patients' autonomy may be diminished by virtue of their illness; evidence shows that even patients who appear to be ideal candidates for understanding and granting informed consent rarely are, particularly those with acute infections. We argue that for low-risk trials whose purpose is to evaluate nonexperimental therapies or other measures towards which the medical community is in a state of equipoise, ethics committees should play a more active role in a more standardized fashion. Patients in the clinic are continually subject to spontaneous 'pseudo-randomizations' based on local dogma and the anecdotal experience of their physicians. Stronger ethics oversight would allow point-of-care trials to structure these spontaneous randomizations, using widely available informatics tools, in combination with opt-out informed consent where deemed appropriate. Copyright © 2016. Published by Elsevier Ltd.

  17. Maximum likelihood decoding analysis of Accumulate-Repeat-Accumulate Codes

    NASA Technical Reports Server (NTRS)

    Abbasfar, Aliazam; Divsalar, Dariush; Yao, Kung

    2004-01-01

    Repeat-Accumulate (RA) codes are the simplest turbo-like codes that achieve good performance. However, they cannot compete with Turbo codes or low-density parity check codes (LDPC) as far as performance is concerned. The Accumulate Repeat Accumulate (ARA) codes, as a subclass of LDPC codes, are obtained by adding a pre-coder in front of RA codes with puncturing where an accumulator is chosen as a precoder. These codes not only are very simple, but also achieve excellent performance with iterative decoding. In this paper, the performance of these codes with (ML) decoding are analyzed and compared to random codes by very tight bounds. The weight distribution of some simple ARA codes is obtained, and through existing tightest bounds we have shown the ML SNR threshold of ARA codes approaches very closely to the performance of random codes. We have shown that the use of precoder improves the SNR threshold but interleaving gain remains unchanged with respect to RA code with puncturing.

  18. Characterizing Adversity of Lysosomal Accumulation in Nonclinical Toxicity Studies: Results from the 5th ESTP International Expert Workshop.

    PubMed

    Lenz, B; Braendli-Baiocco, A; Engelhardt, J; Fant, P; Fischer, H; Francke, S; Fukuda, R; Gröters, S; Harada, T; Harleman, H; Kaufmann, W; Kustermann, S; Nolte, T; Palazzi, X; Pohlmeyer-Esch, G; Popp, A; Romeike, A; Schulte, A; Lima, B Silva; Tomlinson, L; Willard, J; Wood, C E; Yoshida, M

    2018-02-01

    Lysosomes have a central role in cellular catabolism, trafficking, and processing of foreign particles. Accumulation of endogenous and exogenous materials in lysosomes represents a common finding in nonclinical toxicity studies. Histologically, these accumulations often lack distinctive features indicative of lysosomal or cellular dysfunction, making it difficult to consistently interpret and assign adverse dose levels. To help address this issue, the European Society of Toxicologic Pathology organized a workshop where representative types of lysosomal accumulation induced by pharmaceuticals and environmental chemicals were presented and discussed. The expert working group agreed that the diversity of lysosomal accumulations requires a case-by-case weight-of-evidence approach and outlined several factors to consider in the adversity assessment, including location and type of cell affected, lysosomal contents, severity of the accumulation, and related pathological effects as evidence of cellular or organ dysfunction. Lysosomal accumulations associated with cytotoxicity, inflammation, or fibrosis were generally considered to be adverse, while those found in isolation (without morphologic or functional consequences) were not. Workshop examples highlighted the importance of thoroughly characterizing the biological context of lysosomal effects, including mechanistic data and functional in vitro readouts if available. The information provided here should facilitate greater consistency and transparency in the interpretation of lysosomal effects.

  19. [Point-of-Care Testing in Trauma Patients - Methods and Evidence].

    PubMed

    Dirkmann, Daniel; Britten, Martin W; Frey, Ulrich H

    2018-06-01

    In severely injured patients, trauma-induced coagulopathy (TIC) present at hospital admission is associated with increased transfusion requirements, morbidity and mortality. Early and effective treatment contributes to improved survival rates. Laboratory coagulation assays have long turn-around times and evidence for their usefulness, especially in the context of TIC, is weak. Due to the lack of appropriate guidance, transfusion of allogeneic blood products frequently follows a ratio-based concept (e.g., transfusion of erythrocytes and plasma in a 1 : 1 ratio). Point-of-care (PoC) tests enable the assessment of prothrombin time (PT) and activated partial thromboplastin time in few minutes. However, although normal PT in these tests allows to rule out relevant effects of several anticoagulants, they are not able to detect patients with TIC and/or requiring subsequent massive transfusion. Viscoelastic tests (VETs) make it possible to assess defects in thrombin generation, hypofibrinogenaemia, thrombocytopenia, and hyperfibrinolysis, and thus enable targeted therapy. Impairment of platelet function is the common blind spot not detectable using both standard laboratory-based tests and VETs. However, PoC platelet function tests enable to detect platelet defects and patients taking anti-platelet. Furthermore, impaired platelet function has been identified as a strong predictor for coagulopathy and massive transfusion in trauma patients. In other clinical settings, coagulation management based on VETs is associated with decreased transfusion requirements, incidence of acute kidney failure, and mortality, respectively. Data of the first small prospective randomised trial indicate superiority of VET guided coagulation management solely using coagulation factor concentrates, when compared to plasma transfusions in severe trauma. Georg Thieme Verlag KG Stuttgart · New York.

  20. Local accumulation times for spatial difference in morphogen concentration

    NASA Astrophysics Data System (ADS)

    Wen, Xiaoqing; Yin, Hongwei

    During development of multicellular organisms, spatial patterns of cells and tissue organizations rely on the action of morphogens, which are signaling molecules and act as dose-dependent regulators of gene expression and cellular differentiation. Since some experimental evidences have indicated that the spatial difference in morphogen concentration regulates cellular proliferation rather than this concentration profile in developing tissues, we propose spatially discrete models to describe this difference for a synthesis-diffusion-degradation process of morphogen in infinite and finite development fields, respectively. For both of models, we respectively derive analytical expressions of local accumulation times, which are required to form the steady state of the spatial difference in morphogen concentration. Our results show that the local accumulation times for the spatial difference in morphogen concentrations are different from the ones for morphogen concentration profiles.

  1. Spin accumulation in disordered topological insulator ultrathin films

    NASA Astrophysics Data System (ADS)

    Siu, Zhuo Bin; Ho, Cong Son; Tan, Seng Ghee; Jalil, Mansoor B. A.

    2017-08-01

    Topological insulator (TI) ultrathin films differ from the more commonly studied semi-infinite bulk TIs in that the former possess both top and bottom surfaces where the surface states localized at different surfaces can couple to one another across the finite thickness of the film. In the presence of an in-plane magnetization, the TI thin films display two distinct phases depending on which of the inter-surface coupling or the magnetization is stronger. In this work, we consider a Bi2Se3 TI thin film system with an in-plane magnetization and numerically calculate the resulting spin accumulation on both surfaces of the film due to an in-plane electric field to linear order. We describe a numerical scheme for performing the Kubo formula calculation in which we include impurity scattering and vertex corrections. We find that the sums of the spin accumulation over the two surfaces in the in-plane direction perpendicular to the magnetization and in the out of plane direction are antisymmetric in Fermi energy around the charge neutrality point and are non-vanishing only when the symmetry between the top and bottom TI surfaces is broken. The impurity scattering, in general, diminishes the magnitude of the spin accumulation.

  2. Lactofen induces isoflavone accumulation and glyceollin elicitation competency in soybean.

    PubMed

    Landini, Serena; Graham, Madge Y; Graham, Terrence L

    2003-03-01

    Lactofen, the active ingredient of the soybean disease resistance-inducing herbicide, Cobra, induces large accumulations of isoflavone conjugates and aglycones in soybean tissues. The predominant isoflavones induced in cotyledon tissues are daidzein (and its conjugates) and formononetin and glycitein aglycones. The latter two isoflavones are usually present only at very low levels in soybean seedling tissues. In leaves, the predominant lactofen-induced isoflavones are daidzein and formononetin aglycones and the malonyl-glucosyl conjugate of genistein. Isoflavone induction also occurs in cells distal to the point of treatment, but is only weakly systemic. Lactofen also induces elicitation competency, the capacity of soybean cells to accumulate the pterocarpan phytoalexin glyceollin in response to glucan elicitors from the cell wall of the pathogen Phytophthora sojae. Comparison of the activity of a series of diphenyl ether herbicides demonstrated that while all diphenyl ethers tested induced some degree of elicitation competency, only certain ones induced isoflavone accumulation in the absence of glucan elicitor. As a group the diphenyl ethers are thought to inhibit protoporhyrinogen oxidase, eventually leading to singlet oxygen generation. Another singlet oxygen generator, rose bengal, also induced elicitation competency, but little isoflavone accumulation. It is hypothesized that diphenyl ether-induced activated oxygen species mimic some aspects of hypersensitive cell death, which leads to elicitation competency in infected tissues.

  3. A Model for Evidence Accumulation in the Lexical Decision Task

    ERIC Educational Resources Information Center

    Wagenmakers, Eric-Jan; Steyvers, Mark; Raaijmakers, Jeroen G. W.; Shiffrin, Richard M.; van Rijn, Hedderik; Zeelenberg, Rene

    2004-01-01

    We present a new model for lexical decision, REM-LD, that is based on REM theory (e.g., Shiffrin & Steyvers, 1997). REM-LD uses a principled (i.e., Bayes' rule) decision process that simultaneously considers the diagnosticity of the evidence for the 'WORD' response and the 'NONWORD' response. The model calculates the odds ratio that the presented…

  4. Streptococcus mutans Adherence: Presumptive Evidence for Protein-Mediated Attachment Followed by Glucan-Dependent Cellular Accumulation

    PubMed Central

    Staat, Robert H.; Langley, Sharon D.; Doyle, R. J.

    1980-01-01

    Adherence of Streptococcus mutans to smooth surfaces has been attributed to the production of sucrose-derived d-glucans. However, several studies indicate that the bacterium will adhere in the absence of sucrose. The present data confirmed that S. mutans adherence to saliva-coated hydroxyapatite beads in the absence of sucrose is described by the Langmuir equation. The nature of the sucrose-independent adherence was studied with the Persea americana agglutinin as a selective adherence inhibitor. Pretreatment of the bacterium with P. americana agglutinin caused a 10-fold reduction in adherence, and the inhibition was not reversed with the addition of sucrose. Pretreatment of S. mutans with proteases also reduced adherence, regardless of the sucrose content, whereas periodate oxidation and glucanohydrolase treatment of the bacteria reduced sucrose-mediated adherence to the levels found for sucrose-independent adherence. The P. americana agglutinin, glucanohydrolase, and pepsin pretreatment of the cells did not eliminate sucrose-induced agglutination. Scanning electron microscopy showed that short streptococcal chains were bound to saliva-coated hydroxyapatite crystals in the sucrose-independent system, whereas the presence of sucrose caused larger bacterial clumps to be found. A two-reaction model of S. mutans adherence was developed from these data. It is proposed that one reaction is attachment to the tooth pellicle which is mediated by cell-surface proteins rather than glucans or teichoic acids. The other reaction is cellular accumulation mediated by sucrose-derived d-glucans and cell surface lectins. A series of sequential adherence experiments with P. americana agglutinin as a selective inhibitor provided presumptive evidence for the validity of our model of S. mutans adherence. Images Fig. 1 PMID:7380545

  5. Analytical evidence of heterogeneous lead accumulation in the hypothalamic defence area and nucleus tractus solitarius.

    PubMed

    Guimarães, D; Santos, J P; Carvalho, M L; Diniz, M S; House, B; Miller, V M

    2014-09-01

    Lead is a potent toxicant associated with adverse cardiovascular effects and hypertension in children. Yet, few studies have determined if autonomic dysfunction associated with lead exposure involves brain regions which regulate autonomic responses. Central autonomic nuclei such as the nucleus tractus solitarius (NTS) and hypothalamic defence area (HDA) may be particularly sensitive to lead infiltration because they are adjacent to ventricles and areas with semi-permeable blood-brain-barriers. To understand if autonomic nuclei are sensitive to lead accumulation Wistar rats were exposed to lead from the gestational period and lead levels were quantified in brain regions that regulate arterial pressure: the NTS and the HDA. Energy dispersive X-ray fluorescence (EDXRF) was used to quantify total brain lead levels and revealed no differences between exposed and control tissues; measured values were close to the detection limit (2μg/g). Electrothermal atomic absorption spectrometry (ETAAS) was also used, which has a greater sensitivity, to quantify lead. There was ∼2.1μg/g lead in the NTS and ∼3.1μg/g lead in the HDA of exposed rats, and no lead in the control rats. There were greater lead levels in the HDA (∼50%) as compared with the NTS. Pathology studies revealed more prominent lead granules in the HDA as compared with the NTS. Increased microglia and astrocyte activation was also noted in the NTS of lead exposed rats as compared with the HDA. Regional differences in neuro-inflammatory responses likely contribute to heterogeneous lead accumulation, with enhanced clearance of lead in the NTS. Future studies will resolve the mechanisms underpinning tissue-specific lead accumulation. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. [Current Practice of Pre- and Postnatal Screening and Future Developments for Evidence Based Guidelines].

    PubMed

    Hebebrand, J; Hamelmann, E; Hartmann, A; Holtmann, M; Jöckel, K-H; Kremer, U; Legenbauer, T; Lücke, T; Radkowski, K; Reinehr, T; Wand, K; Mühlig, Y; Föcker, M

    2017-01-01

    Objectives: In this selective review we provide an overview of the current pre- and postnatal screenings up to 18 years established in Germany to inform physicians of different medical fields (gynecologists, pediatricians, general practitioners, other medical specialists who treat children, adolescents or pregnant females). Current State: Research on screening for different types of cancer has frequently failed to show any benefit. Thus, there is a need to broaden the evidence basis related to medical screenings especially for children and adolescents. Outlook: Potential future developments of pre- and postnatal screenings are illustrated including their social impact. The lack of an early detection of mental health problems is pointed out. An interdisciplinary collaboration and research is required to accumulate evidence with regard to medical screenings and to consider health economic and ethical aspects. © Georg Thieme Verlag KG Stuttgart · New York.

  7. Evidence of 3-D Reconnection at Null Point from the Observations of Circular Flares and Homologous Jets

    NASA Astrophysics Data System (ADS)

    Wang, Haimin; Liu, C.

    2012-05-01

    In recent studies by Pariat, Antiochos and DeVore (2009, 2010), fan-separatrix topology and magnetic reconnection at the null-point were simulated and found to produce homologous jets. This motivates us to search for axisymmetric magnetic structure and associated flaring/jetting activity. Using high-resolution ( 0.15" per pixel) and high-cadence ( 15 s) H-alpha center/offband observations obtained from the recently digitized films of Big Bear Solar Observatory, we were able to identify five large circular flares with associated surges. All the events exhibit a central parasite magnetic field surrounded by opposite polarity, forming a circular polarity inversion line (PIL). Consequently, a compact flare kernel at the center is surrounded by a circular ribbon, and together with the upward ejecting dark surge, these seem to depict a dome-like magnetic structure. Very interestingly, (1) the circular ribbon brightens sequentially rather than simultaneously, (2) the central compact flare kernel shows obvious motion, and (3) a remote elongated, co-temporal flare ribbon at a region with the same polarity as the central parasite site is seen in the series of four homologous events on 1991 March 17 and 18. The remote ribbon is 120" away from the jet location. Moreover, magnetic reconnection across the circular PIL is evident from the magnetic flux cancellation. These rarely observed homologous surges with circular as well as central and remote flare ribbons provide valuable evidence concerning the dynamics of magnetic reconnection in a null-point topology. This study is dedicated to Professor Hal Zirin, the founder of Big Bear Solar Observatory, who passed away on January 3, 2012.

  8. The influence of large wood accumulations on riparian seed bank diversity

    NASA Astrophysics Data System (ADS)

    Osei, N. A.

    2012-04-01

    Little is known about the structure and complexity of seed bank within the riparian corridor and the how large wood accumulations contribute to riparian seed bank diversity. This study aimed to examine and quantify seed bank assemblage and diversity along the undisturbed riparian corridor of the Highland Water, a second order lowland stream draining the New Forest. Seed bank samples were collected from five riparian corridor microhabitats namely mid-channel bars, floodplains, bare banks, banks adjacent large wood accumulations and within large wood accumulations that differed in their hydrologic connectivity with the river. Descriptive statistics and ordination methods applied to the floristic and sediment data sets indicates that sediment organic matter content, species richness and proportions of functional types distinctly differed among the riparian microhabitats types but there was no difference in viable seed densities. Banks adjacent large wood accumulations were the most floristically diverse and rich in organic matter with mid-channel bars exhibiting the reverse. This was due to the ability of large wood accumulations to buffer varying magnitudes of physical gradients and sort seeds and sediments, therefore altering the character of bare banks. This study not only strengthen the evidence that riparian corridors exhibit elevated spatial sediment and vegetation heterogeneity but also demonstrates the importance of large wood accumulation as habitat modifiers, ecosystem engineers and conservation sink for moisture, organic matter and seeds, resources essential for riparian vegetation conservation, recovery and restoration efforts.

  9. Accumulation of polyubiquitylated proteins in response to Ala-Ala-Phe-chloromethylketone is independent of the inhibition of Tripeptidyl peptidase II.

    PubMed

    Villasevil, Eugenia M; Guil, Sara; López-Ferreras, Lorena; Sánchez, Carlos; Del Val, Margarita; Antón, Luis C

    2010-09-01

    In the present study we have addressed the issue of proteasome independent cytosolic protein degradation. Tripeptidyl peptidase II (TPPII) has been suggested to compensate for a reduced proteasome activity, partly based on evidence using the inhibitor Ala-Ala-Phe-chloromethylketone (AAF-cmk). Here we show that AAF-cmk induces the formation of polyubiquitin-containing accumulations in osteosarcoma and Burkitt's lymphoma cell lines. These accumulations meet many of the landmarks of the aggresomes that form after proteasome inhibition. Using a combination of experiments with chemical inhibitors and interference of gene expression, we show that TPPII inhibition is not responsible for these accumulations. Our evidence suggests that the relevant target(s) is/are in the ubiquitin-proteasome pathway, most likely upstream the proteasome. We obtained evidence supporting this model by inhibition of Hsp90, which also acts upstream the proteasome. Although our data suggest that Hsp90 is not a target of AAF-cmk, its inhibition resulted in accumulations similar to those obtained with AAF-cmk. Therefore, our results question the proposed role for TPPII as a prominent alternative to the proteasome in cellular proteolysis. Copyright 2010 Elsevier B.V. All rights reserved.

  10. Preferential Osmolyte Accumulation: a Mechanism of Osmotic Stress Adaptation in Diazotrophic Bacteria

    PubMed Central

    Madkour, Magdy A.; Smith, Linda Tombras; Smith, Gary M.

    1990-01-01

    A common cellular mechanism of osmotic-stress adaptation is the intracellular accumulation of organic solutes (osmolytes). We investigated the mechanism of osmotic adaptation in the diazotrophic bacteria Azotobacter chroococcum, Azospirillum brasilense, and Klebsiella pneumoniae, which are adversely affected by high osmotic strength (i.e., soil salinity and/or drought). We used natural-abundance 13C nuclear magnetic resonance spectroscopy to identify all the osmolytes accumulating in these strains during osmotic stress generated by 0.5 M NaCl. Evidence is presented for the accumulation of trehalose and glutamate in Azotobacter chroococcum ZSM4, proline and glutamate in Azospirillum brasilense SHS6, and trehalose and proline in K. pneumoniae. Glycine betaine was accumulated in all strains grown in culture media containing yeast extract as the sole nitrogen source. Alternative nitrogen sources (e.g., NH4Cl or casamino acids) in the culture medium did not result in measurable glycine betaine accumulation. We suggest that the mechanism of osmotic adaptation in these organisms entails the accumulation of osmolytes in hyperosmotically stressed cells resulting from either enhanced uptake from the medium (of glycine betaine, proline, and glutamate) or increased net biosynthesis (of trehalose, proline, and glutamate) or both. The preferred osmolyte in Azotobacter chroococcum ZSM4 shifted from glutamate to trehalose as a consequence of a prolonged osmotic stress. Also, the dominant osmolyte in Azospirillum brasilense SHS6 shifted from glutamate to proline accumulation as the osmotic strength of the medium increased. PMID:16348295

  11. Multidrug Efflux Transporters Limit Accumulation of Inorganic, but Not Organic, Mercury in Sea Urchin Embryos

    PubMed Central

    Bošnjak, Ivana; Uhlinger, Kevin R.; Heim, Wesley; Smital, Tvrtko; Franekić-Čolić, Jasna; Coale, Kenneth; Epel, David; Hamdoun, Amro

    2011-01-01

    Mercuric compounds are persistent global pollutants that accumulate in marine organisms and in humans who consume them. While the chemical cycles and speciation of mercury in the oceans are relatively well described, the cellular mechanisms that govern which forms of mercury accumulate in cells and why they persist are less understood. In this study we examined the role of multidrug efflux transport in the differential accumulation of inorganic (HgCl2) and organic (CH3HgCl) mercury in sea urchin (Strongylocentrotus purpuratus) embryos. We found that inhibition of MRP/ABCC-type transporters increases intracellular accumulation of inorganic mercury but had no effect on accumulation of organic mercury. Similarly, pharmacological inhibition of metal conjugating enzymes by ligands GST/GSH significantly increases this antimitotic potency of inorganic mercury, but had no effect on the potency of organic mercury. Our results point to MRP-mediated elimination of inorganic mercury conjugates as a cellular basis for differences in the accumulation and potency of the two major forms of mercury found in marine environments. PMID:19924972

  12. Re-accumulation of Asteroids to Equilibrium Figures

    NASA Astrophysics Data System (ADS)

    Hestroffer, D.; Tanga, P.; Richardson, D. C.; Berthier, J.; Cellino, A.; Durech, J.; Michel, P.

    2008-09-01

    Since their formation, asteroids since their formation have experienced little physical, geological or thermal evolution. Like comets they are thought to be among the most pristine remnants of the early solar system. One physical process, however, has played a major role since the ancient times: collisions. Dynamical families were produced by catastrophic collisions involving large enough energy to break the parent body. Other lines of evidence suggest that catastrophic collisions can also produce rubble-piles, i.e., loosely bound of post-collisional aggregates that re-accumulate to form a single body, and are kept together by gravity. The main objective of this work is to understand if—and under what conditions—Jacobi ellipsoids or other equilibrium figures can be obtained naturally by this way. This is done by performing numerical experiments simulating the re-accumulation process, and by performing high-angular resolution observations in order to better constrain the shape and density of the targets. It is shown that the outcomes of reaccumulation events tend to produce a rather narrow variety of possible shapes, and in some cases also binary systems.

  13. [Secondary metabolites accumulating and geoherbs formation under enviromental stress].

    PubMed

    Huang, Lu-Qi; Guo, Lan-Ping

    2007-02-01

    This paper analyzed how habitat affected the formation of geoherbs after summarizing the influences of environmental stress on plants growth, especially on theirs secondary metabolites accumulating, and introducing 4 kinds hypothesis about environmental stress affects plants. It was then pointed out that environmental stress may have advantage on the formation of geoherbs. The stress effect hypothesis on forming geoherbs was brought forward, and the ways and methods on study the geoherbs under environmental stress was discussed.

  14. Articulating the history and major departure points evident in post-apartheid South African national water policy and law

    NASA Astrophysics Data System (ADS)

    Chikozho, C.; Danga, L.; Saruchera, D.

    2017-08-01

    Governance of the water sector in South Africa has reflected the political changes taking place in society. For instance, due to apartheid policies of segregation, inequality of access to water resources marks South Africa's history in a very profound way and redistribution of rights to water to redress the results of past discrimination became an explicit purpose of the post-apartheid water governance policy and legislative regime. In this paper, we articulate the history and major departure points evident in post-apartheid South African national water policy and law. This includes documenting and reflecting on most of the available information that shows how the new water policy and law were developed. Findings from the study show that the key players active in the water law review process deliberately took into account the political goals and dynamics of power asymmetry within which the law was being articulated. Therefore, the water law as it stands today and in the past must be understood within the context of the socio-economic and political landscape that has prevailed in South Africa at different historical junctures. We contend that a detailed examination and articulation of the history and major departure points evident in post-apartheid South African national water policy and law enables practitioners and scholars to better understand the main motivations behind the water sector reforms and the then prevailing thinking behind the policy and legislation eventually promulgated. The present water law must be understood in the context of these reforms and the objectives they sought to achieve.

  15. Outstanding accumulation of Sphagnum palustre in central-southern Italy

    NASA Astrophysics Data System (ADS)

    Casella, Laura; Zaccone, Claudio

    2017-04-01

    Lake Fibreno is a site where some outstanding anomalies for the flora and vegetation of the wetlands of peninsular Italy are concentrated. Here one the southernmost European population of Sphagnum palustre occurs, and is restricted on the surface of a free-floating island, i.e., a round-shaped portion of fen (with a core of Sphagnum), erratically floating on the surface of a submerged sinkhole. Geological evidences point out the existence in the area of a large lacustrine basin since Late Pleistocene. The progressive filling of the lake, caused by changing in climatic conditions and neotectonic events, resulted in the formation of peat deposits in the area, following different depositional cycles in a swampy environment. So that, the studied free-floating island, probably originated around lake margins in the waterlogged area, was somehow isolated from the bank and started to float. Once the separation occurred, sedge peat stopped to accumulate, thus enhancing the role of S. palustre as the main peat-forming plant. The vegetation occurring at the moment of the isolation of the island was a coverage of Salix cinerea/Populus tremula stands below which cushions of moss and, in a lower extent, Thelypteris palustris/Equisetum palustre accumulated resulting in the formation of 2-3 meters of peat dominated by reeds and sedges. This vegetation has been partially degraded by grazing until 1970s, while in 1980s the lake became a nature reserve. Since then, the succession could resume in a spontaneous and natural way and it was possible for the vegetation to recover to natural dynamics and growing rate. The Sphagnum tussocks were measured in an empirical way at a distance of about 60 years after the last signaling and the result was a measurement of an accretion open to about 70 cm thick. Moreover, in a recent study, a 4-m deep peat core was collected from the centre of the island and results were surprising. In fact, 14C age dating, confirmed using 210Pb and 137Cs, showed

  16. Zinc finger point mutations within the WT1 gene in Wilms tumor patients.

    PubMed Central

    Little, M H; Prosser, J; Condie, A; Smith, P J; Van Heyningen, V; Hastie, N D

    1992-01-01

    A proposed Wilms tumor gene, WT1, which encodes a zinc finger protein, has previously been isolated from human chromosome 11p13. Chemical mismatch cleavage analysis was used to identify point mutations in the zinc finger region of this gene in a series of 32 Wilms tumors. Two exonic single base changes were detected. In zinc finger 3 of a bilateral Wilms tumor patient, a constitutional de novo C----T base change was found changing an arginine to a stop codon. One tumor from this patient showed allele loss leading to 11p hemizygosity of the abnormal allele. In zinc finger 2 of a sporadic Wilms tumor patient, a C----T base change resulted in an arginine to cysteine amino acid change. To our knowledge, a WT1 gene missense mutation has not been detected previously in a Wilms tumor. By comparison with a recent NMR and x-ray crystallographic analysis of an analogous zinc finger gene, early growth response gene 1 (EGR1), this amino acid change in WT1 occurs at a residue predicted to be critical for DNA binding capacity and site specificity. The detection of one nonsense point mutation and one missense WT1 gene point mutation adds to the accumulating evidence implicating this gene in a proportion of Wilms tumor patients. Images PMID:1317572

  17. 5-Aminolevulinic Acid Accumulation in a Cerebral Infarction Mimicking High-Grade Glioma.

    PubMed

    Behling, Felix; Hennersdorf, Florian; Bornemann, Antje; Tatagiba, Marcos; Skardelly, Marco

    2016-08-01

    5-Aminolevulinic acid (5-ALA) has become an integral part in the neurosurgical treatment of malignant glioma. Over time, several other tumor entities have been identified to metabolize 5-ALA and show a similar fluorescence pattern during surgical resection. This case report is the first description of 5-ALA accumulation in postischemic cerebral tissue. This evidence questions the assumption that 5-ALA accumulation in glioma is exclusively attributed to tumor infiltration. Instead, 5-ALA accumulation can also occur beyond the tumor borders and may be partially ascribed to inflammatory changes in the surrounding brain tissue. A 64-year old woman presented with episodes of apraxia and a ring-enhancing lesion in postcontrast T1-weighted magnetic resonance sequences suggestive of high grade glioma. Strong fluorescence was observed during 5-ALA-guided resection. However, although the frozen section was inconclusive, the final histopathologic examination revealed a stage II cerebral infarction. 5-ALA accumulation in postischemic cerebral tissue should be considered for intended supramarginal resections near eloquent brain regions. Therefore, sufficient preoperative imaging should regularly include magnetic resonance imaging spectroscopy and perfusion sequences to ascertain the proper diagnosis. Moreover, further research is warranted to determine the role of 5-ALA accumulation in postischemic and inflammatory brain tissue. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. Sheath-accumulating Propagation of Interplanetary Coronal Mass Ejection

    NASA Astrophysics Data System (ADS)

    Takahashi, Takuya; Shibata, Kazunari

    2017-03-01

    Fast interplanetary coronal mass ejections (ICMEs) are the drivers of strong space weather storms such as solar energetic particle events and geomagnetic storms. The connection between the space-weather-impacting solar wind disturbances associated with fast ICMEs at Earth and the characteristics of causative energetic CMEs observed near the Sun is a key question in the study of space weather storms, as well as in the development of practical space weather prediction. Such shock-driving fast ICMEs usually expand at supersonic speeds during the propagation, resulting in the continuous accumulation of shocked sheath plasma ahead. In this paper, we propose a “sheath-accumulating propagation” (SAP) model that describes the coevolution of the interplanetary sheath and decelerating ICME ejecta by taking into account the process of upstream solar wind plasma accumulation within the sheath region. Based on the SAP model, we discuss (1) ICME deceleration characteristics; (2) the fundamental condition for fast ICMEs at Earth; (3) the thickness of interplanetary sheaths; (4) arrival time prediction; and (5) the super-intense geomagnetic storms associated with huge solar flares. We quantitatively show that not only the speed but also the mass of the CME are crucial for discussing the above five points. The similarities and differences between the SAP model, the drag-based model, and the“snow-plow” model proposed by Tappin are also discussed.

  19. Sheath-accumulating Propagation of Interplanetary Coronal Mass Ejection

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

    Takahashi, Takuya; Shibata, Kazunari, E-mail: takahasi@kusastro.kyoto-u.ac.jp

    Fast interplanetary coronal mass ejections (ICMEs) are the drivers of strong space weather storms such as solar energetic particle events and geomagnetic storms. The connection between the space-weather-impacting solar wind disturbances associated with fast ICMEs at Earth and the characteristics of causative energetic CMEs observed near the Sun is a key question in the study of space weather storms, as well as in the development of practical space weather prediction. Such shock-driving fast ICMEs usually expand at supersonic speeds during the propagation, resulting in the continuous accumulation of shocked sheath plasma ahead. In this paper, we propose a “sheath-accumulating propagation”more » (SAP) model that describes the coevolution of the interplanetary sheath and decelerating ICME ejecta by taking into account the process of upstream solar wind plasma accumulation within the sheath region. Based on the SAP model, we discuss (1) ICME deceleration characteristics; (2) the fundamental condition for fast ICMEs at Earth; (3) the thickness of interplanetary sheaths; (4) arrival time prediction; and (5) the super-intense geomagnetic storms associated with huge solar flares. We quantitatively show that not only the speed but also the mass of the CME are crucial for discussing the above five points. The similarities and differences between the SAP model, the drag-based model, and the“snow-plow” model proposed by Tappin are also discussed.« less

  20. MARRIAGE AND MEN’S WEALTH ACCUMULATION IN THE UNITED STATES, 1860-1870

    PubMed Central

    HONG, SOK CHUL

    2013-01-01

    This paper explores how changes in marital status affected men’s wealth accumulation in mid-nineteenth-century America, using a longitudinal sample of Union Army veterans linked to the 1860 and 1870 census manuscript schedules. Controlling for the endogeneity of wealth and marital selection, this paper provides strong evidence that marriage had positive effects on men’s wealth accumulation, whereas ending a marriage had negative effects. The estimated wealth premium on married men is about 60 percent per marital year. This substantial wealth premium is closely related to wives’ specializing in household production, and farmers and craftsmen economically benefited from the unpaid labor of their wives. PMID:24058226

  1. Multi-window detection for P-wave in electrocardiograms based on bilateral accumulative area.

    PubMed

    Chen, Riqing; Huang, Yingsong; Wu, Jian

    2016-11-01

    P-wave detection is one of the most challenging aspects in electrocardiograms (ECGs) due to its low amplitude, low frequency, and variable waveforms. This work introduces a novel multi-window detection method for P-wave delineation based on the bilateral accumulative area. The bilateral accumulative area is calculated by summing the areas covered by the P-wave curve with left and right sliding windows. The onset and offset of a positive P-wave correspond to the local maxima of the area detector. The position drift and difference in area variation of local extreme points with different windows are used to systematically combine multi-window and 12-lead synchronous detection methods, which are used to screen the optimization boundary points from all extreme points of different window widths and adaptively match the P-wave location. The proposed method was validated with ECG signals from various databases, including the Standard CSE Database, T-Wave Alternans Challenge Database, PTB Diagnostic ECG Database, and the St. Petersburg Institute of Cardiological Technics 12-Lead Arrhythmia Database. The average sensitivity Se was 99.44% with a positive predictivity P+ of 99.37% for P-wave detection. Standard deviations of 3.7 and 4.3ms were achieved for the onset and offset of P-waves, respectively, which is in agreement with the accepted tolerances required by the CSE committee. Compared with well-known delineation methods, this method can achieve high sensitivity and positive predictability using a simple calculation process. The experiment results suggest that the bilateral accumulative area could be an effective detection tool for ECG signal analysis. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Demise of reef-flat carbonate accumulation with late Holocene sea-level fall: Evidence from Molokai, Hawaii

    USGS Publications Warehouse

    Engels, M.S.; Fletcher, C.H.; Field, M.; Conger, C.L.; Bochicchio, C.

    2008-01-01

    Twelve cores from the protected reef-flat of Molokai revealed that carbonate sediment accumulation, ranging from 3 mm year-1 to less than 1 mm year-1, ended on average 2,500 years ago. Modern sediment is present as a mobile surface veneer but is not trapped within the reef framework. This finding is consistent with the arrest of deposition at the end of the mid-Holocene highstand, known locally as the "Kapapa Stand of the Sea," ???2 m above the present datum ca. 3,500 years ago in the main Hawaiian Islands. Subsequent erosion, non-deposition, and/or a lack of rigid binding were probable factors leading to the lack of reef-flat accumulation during the late Holocene sea-level fall. Given anticipated climate changes, increased sedimentation of reef-flat environments is to be expected as a consequence of higher sea level. ?? 2008 Springer-Verlag.

  3. Temporal and spatial variations on accumulation of nomilin and limonin in the pummelos.

    PubMed

    Wang, Fusheng; Yu, Xiaohan; Liu, Xiaona; Shen, Wanxia; Zhu, Shiping; Zhao, Xiaochun

    2016-09-01

    Limonoids are the important secondary metabolites in the citrus. In this study, the accumulation of limonoids at different fruit developmental stages and distribution among different genotypes, tissues and developmental stages were investigated in 12 pummelo varieties. The large variations on limonoids concentration were found among different varieties, which ranged from 233.78 mg/kg FW to 4090.41 mg/kg FW in the seeds at full color stage of the fruit. Classification of pummelos based on the limonoids content divided 12 varieties into three groups. It was matched well with the geographic origination of the pummelo varieties, suggesting that the accumulation of limonoids was mainly determined by the genotype of the pummelo. Accumulation of the limonoids in different tissues was highly variable, and in a tissue specific fashion. The trend of the change on the levels of nomilin and limonin in the seeds and segment membrane were corresponded to the physiological development of the fruit. The rapid accumulation of nomilin and limonoids was observed from the physiological ripening of the seeds. It suggested that physiological maturation of the seeds is a key point that the seeds accelerate the accumulation of nomilin and limonin. In most of pummelo varieties, 10% color break of the fruit was a phenotypic landmark associated with the maximum level of nomilin accumulated in the seeds. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  4. Lifespan mercury accumulation pattern in Liza aurata : Evidence from two southern European estuaries

    NASA Astrophysics Data System (ADS)

    Tavares, S.; Oliveira, H.; Coelho, J. P.; Pereira, M. E.; Duarte, A. C.; Pardal, M. A.

    2011-10-01

    Mercury accumulation throughout the lifespan of Liza aurata (Risso, 1810) was analysed in four tissues (muscle, gills, liver and brain) in two southern European coastal ecosystems with distinct mercury contamination. Specimens from four to five age classes were captured in two sampling sites in the Ria de Aveiro (Laranjo bay and Mira), a system historically contaminated by industrial mercury, and in one site in the Mondego estuary, assumed as a mercury-free ecosystem. Mercury concentration in all tissues was found to be significantly higher in the Ria de Aveiro (Laranjo bay) compared to the Mondego, in accordance with the environmental contamination (water, sediments and suspended particulate matter). Significant differences inside the Ria de Aveiro (between the Mira and Laranjo bay) were only detected in the liver. This tissue registered the highest levels of mercury (ranging from 0.11 to 4.2 μg g -1 ) in all sampling sites, followed by muscle, brain, and gills. In all sampling sites and tissues was denoted a mercury dilution pattern along the lifecycle (except in liver at the Mondego, the reference area where the concentrations are always very low). An exponential trend was found in the metal age variation patterns in Laranjo (the most contaminated area) and a linear trend in the Mira and the Mondego (the least contaminated areas). Organic mercury concentration in muscle generally accounted for over 95% of total mercury concentration, and followed the same accumulation pattern of total mercury. This fish species is of lesser importance in mercury transfer to adjacent coastal areas and although the consumption of fish from Laranjo may present some risk for the humans, this risk decreases with fish age/size.

  5. Character, paleoenvironment, rate of accumulation, and evidence for seismic triggering of Holocene turbidites, Canada Abyssal Plain, Arctic Ocean

    USGS Publications Warehouse

    Grantz, A.; Phillips, R.L.; Mullen, M.W.; Starratt, S.W.; Jones, Glenn A.; Naidu, A.S.; Finney, B.P.

    1996-01-01

    Four box cores and one piston core show that Holocene sedimentation on the southern Canada Abyssal Plain for the last 8010??120 yr has consisted of a continuing rain of pelagic organic and ice-rafted elastic sediment with a net accumulation rate during the late Holocene of ???10 mm/1000 yr, and episodically emplaced turbidites 1-5 m thick deposited at intervals of 830 to 3450 yr (average 2000 yr). The average net accumulation rate of the mixed sequence of turbidites and thin pelagite interbeds in the cores is about 1.2 m/1000 yr. Physiography suggests that the turbidites originated on the Mackenzie Delta or its clinoform, and ??13C values of -27 to - 25??? in the turbidites are compatible with a provenance on a delta. Extant displaced neritic and lower slope to basin plain calcareous benthic foraminifers coexist in the turbidite units. Their joint occurence indicates that the turbidites originated on the modern continental shelf and entrained sediment from the slope and rise enroute to their final resting place on the Canada Abyssal Plain. The presence of Middle Pleistocene diatoms in the turbidites suggests, in addition, that the turbidites may have originated in shallow submarine slides beneath the upper slope or outer shelf. Small but consistent differences in organic carbon content and ??13C values between the turbidite units suggest that they did not share an identical provenance, which is at least compatible with an origin in slope failures. The primary provenance of the ice-rafted component of the pelagic beds was the glaciated terrane of northwestern Canada; and the provenance of the turbidite units was Pleistocene and Holocene sedimentary deposits on the outer continental shelf and upper slope of the Mackenzie Delta. Largely local derivation of the sediment of the Canada Abyssal Plain indicates that sediment accumulation rates in the Arctic Ocean are valid only for regions with similar depositional sources and processes, and that these rates cannot be

  6. Masked nonword repetition effects in yes/no and go/no-go lexical decision: a test of the evidence accumulation and deadline accounts.

    PubMed

    Perea, Manuel; Gómez, Pablo; Fraga, Isabel

    2010-06-01

    The pattern of masked repetition priming effects for word and nonword targets differs across tasks: Masked-priming effects in lexical decision occur for positive responses (i.e., words), but not for negative responses (nonwords), whereas masked-priming effects in the cross-case same-different task occur for positive responses (same), but not for negative responses (different)--regardless of lexical status. Here, we examined whether masked nonword priming effects are greater when the task involves an active go response to nonwords than when it involves the standard yes/no procedure in lexical decision. The obtained masked repetition priming effect for nonwords was of similar size in yes/no and go/no-go tasks. This finding is compatible with accounts of nonword priming that posit that nonword responses are produced by actively accumulating evidence for the nonword alternative in yes/no and go/no-go procedures, whereas it is inconsistent with the assumption of a deadline for no responses in the yes/no task.

  7. Delay in micro-discharges appearance during PEO of Al: Evidence of a mechanism of charge accumulation at the electrolyte/oxide interface

    NASA Astrophysics Data System (ADS)

    Martin, J.; Nominé, A.; Brochard, F.; Briançon, J.-L.; Noël, C.; Belmonte, T.; Czerwiec, T.; Henrion, G.

    2017-07-01

    PEO was conducted on Al by applying a pulsed bipolar current. The role of the cathodic polarization on the appearance of micro-discharges (MDs) and on the subsequent formation of the PEO oxide layers is investigated. Various ratios of the charge quantity RCQ = Qp/Qn (defined as the anodic Qp to cathodic Qn charge quantity ratio over one current pulse period) in the range [0.5; 6.0] were selected by changing the waveform parameters of the cathodic current while keeping the waveform of the anodic current unchanged. Results show that the appearance of MDs is delayed with respect to the rising edge of the anodic current; this delay strongly depends on both the processing time and the applied cathodic charge quantity. It is also evidenced that shorter delays promoted by high RCQ values (RCQ > 1) are associated with stronger MDs (large size and long life) that have detrimental effects on the formed PEO oxide layers. Thicker and the more compact oxide layer morphology is achieved with the intermediate RCQ value (RCQ = 0.9) for which the delay of the MDs appearance is high and the MDs softer. Low RCQ (RCQ < 0.9) results in an earlier extinction of the MDs as the process goes on, which leads to poorly oxidized metal. A mechanism of charge accumulation taking place at the oxide/electrolyte interface and arising before the occurrence of dielectric breakdown is proposed to explain the ignition of MDs during pulsed bipolar PEO of aluminium. A close examination of the voltage-time response which can be adequately simulated with an equivalent RC circuit evidences the capacitive behaviour of the oxide layer and therefore confirms this proposed mechanism of charge accumulation.

  8. Evidence for Late Holocene earthquakes on the Utsalady Point fault, Northern Puget Lowland, Washington

    USGS Publications Warehouse

    Johnson, S.Y.; Nelson, A.R.; Personius, S.F.; Wells, R.E.; Kelsey, H.M.; Sherrod, B.L.; Okumura, K.; Koehler, R.; Witter, R.C.; Bradley, L.A.; Harding, D.J.

    2004-01-01

    Trenches across the Utsalady Point fault in the northern Puget Lowland of Washington reveal evidence of at least one and probably two late Holocene earthquakes. The "Teeka" and "Duffers" trenches were located along a 1.4-km-long, 1-to 4-m-high, northwest-trending, southwest-facing, topographic scarp recognized from Airborne Laser Swath Mapping. Glaciomarine drift exposed in the trenches reveals evidence of about 95 to 150 cm of vertical and 200 to 220 cm of left-lateral slip in the Teeka trench. Radiocarbon ages from a buried soil A horizon and overlying slope colluvium along with the historical record of earthquakes suggest that this faulting occurred 100 to 400 calendar years B.P. (A.D. 1550 to 1850). In the Duffers trench, 370 to 450 cm of vertical separation is accommodated by faulting (???210 cm) and folding (???160 to 240 cm), with probable but undetermined amounts of lateral slip. Stratigraphic relations and radiocarbon ages from buried soil, colluvium, and fissure fill in the hanging wall suggest the deformation at Duffers is most likely from two earthquakes that occurred between 100 to 500 and 1100 to 2200 calendar years B.P., but deformation during a single earthquake is also possible. For the two-earthquake hypothesis, deformation at Teeka trench in the first event involved folding but not faulting. Regional relations suggest that the earthquake(s) were M ??? ???6.7 and that offshore rupture may have produced tsunamis. Based on this investigation and related recent studies, the maximum recurrence interval for large ground-rupturing crustal-fault earthquakes in the Puget Lowland is about 400 to 600 years or less.

  9. Mineral transformation and biomass accumulation associated with uranium bioremediation at Rifle, Colorado

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

    Li, L.; Steefel, C.I.; Williams, K.H.

    2009-04-20

    Injection of organic carbon into the subsurface as an electron donor for bioremediation of redox-sensitive contaminants like uranium often leads to mineral transformation and biomass accumulation, both of which can alter the flow field and potentially bioremediation efficacy. This work combines reactive transport modeling with a column experiment and field measurements to understand the biogeochemical processes and to quantify the biomass and mineral transformation/accumulation during a bioremediation experiment at a uranium contaminated site near Rifle, Colorado. We use the reactive transport model CrunchFlow to explicitly simulate microbial community dynamics of iron and sulfate reducers, and their impacts on reaction rates.more » The column experiment shows clear evidence of mineral precipitation, primarily in the form of calcite and iron monosulfide. At the field scale, reactive transport simulations suggest that the biogeochemical reactions occur mostly close to the injection wells where acetate concentrations are highest, with mineral precipitate and biomass accumulation reaching as high as 1.5% of the pore space. This work shows that reactive transport modeling coupled with field data can be an effective tool for quantitative estimation of mineral transformation and biomass accumulation, thus improving the design of bioremediation strategies.« less

  10. Mechanisms of formation and accumulation of mitochondrial DNA deletions in aging neurons.

    PubMed

    Fukui, Hirokazu; Moraes, Carlos T

    2009-03-15

    Age-dependent accumulation of partially deleted mitochondrial DNA (DeltamtDNA) has been suggested to contribute to aging and the development of age-associated diseases including Parkinson's disease. However, the molecular mechanisms underlying the generation and accumulation of DeltamtDNA have not been addressed in vivo. In this study, we have developed a mouse model expressing an inducible mitochondria-targeted restriction endonuclease (PstI). Using this system, we could trigger mtDNA double-strand breaks (DSBs) in adult neurons. We found that this transient event leads to the generation of a family of DeltamtDNA with features that closely resemble naturally-occurring mtDNA deletions. The formation of these deleted species is likely to be mediated by yet uncharacterized DNA repairing machineries that participate in homologous recombination and non-homologous end-joining. Furthermore, we obtained in vivo evidence that DeltamtDNAs with larger deletions accumulate faster than those with smaller deletions, implying a replicative advantage of smaller mtDNAs. These findings identify DSB, DNA repair systems and replicative advantage as likely mechanisms underlying the generation and age-associated accumulation of DeltamtDNA in mammalian neurons.

  11. Mineral transformation and biomass accumulation associated with uranium bioremediation at Rifle, Colorado.

    PubMed

    Li, Li; Steefel, Carl I; Williams, Kenneth H; Wilkins, Michael J; Hubbard, Susan S

    2009-07-15

    Injection of organic carbon into the subsurface as an electron donor for bioremediation of redox-sensitive contaminants like uranium often leads to mineral transformation and biomass accumulation, both of which can alter the flow field and potentially bioremediation efficacy. This work combines reactive transport modeling with a column experiment and field measurements to understand the biogeochemical processes and to quantify the biomass and mineral transformation/accumulation during a bioremediation experiment at a uranium contaminated site near Rifle, Colorado. We use the reactive transport model CrunchFlow to explicitly simulate microbial community dynamics of iron and sulfate reducers, and their impacts on reaction rates. The column experiment shows clear evidence of mineral precipitation, primarily in the form of calcite and iron monosulfide. At the field scale, reactive transport simulations suggest that the biogeochemical reactions occur mostly close to the injection wells where acetate concentrations are highest, with mineral precipitate and biomass accumulation reaching as high as 1.5% of the pore space. This work shows that reactive transport modeling coupled with field data can bean effective tool for quantitative estimation of mineral transformation and biomass accumulation, thus improving the design of bioremediation strategies.

  12. Atomistic simulation of damage accumulation and amorphization in Ge

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

    Gomez-Selles, Jose L., E-mail: joseluis.gomezselles@imdea.org; Martin-Bragado, Ignacio; Claverie, Alain

    2015-02-07

    Damage accumulation and amorphization mechanisms by means of ion implantation in Ge are studied using Kinetic Monte Carlo and Binary Collision Approximation techniques. Such mechanisms are investigated through different stages of damage accumulation taking place in the implantation process: from point defect generation and cluster formation up to full amorphization of Ge layers. We propose a damage concentration amorphization threshold for Ge of ∼1.3 × 10{sup 22} cm{sup −3} which is independent on the implantation conditions. Recombination energy barriers depending on amorphous pocket sizes are provided. This leads to an explanation of the reported distinct behavior of the damage generated by different ions.more » We have also observed that the dissolution of clusters plays an important role for relatively high temperatures and fluences. The model is able to explain and predict different damage generation regimes, amount of generated damage, and extension of amorphous layers in Ge for different ions and implantation conditions.« less

  13. Carbon isotope evidence for recent climate-related enhancement of CO 2 assimilation and peat accumulation rates in Antarctica.

    PubMed

    Royles, Jessica; Ogée, Jérôme; Wingate, Lisa; Hodgson, Dominic A; Convey, Peter; Griffiths, Howard

    2012-10-01

    Signy Island, maritime Antarctic, lies within the region of the Southern Hemisphere that is currently experiencing the most rapid rates of environmental change. In this study, peat cores up to 2 m in depth from four moss banks on Signy Island were used to reconstruct changes in moss growth and climatic characteristics over the late Holocene. Measurements included radiocarbon dating (to determine peat accumulation rates) and stable carbon isotope composition of moss cellulose (to estimate photosynthetic limitation by CO 2 supply and model CO 2 assimilation rate). For at least one intensively 14 C-dated Chorisodontium aciphyllum moss peat bank, the vertical accumulation rate of peat was 3.9 mm yr -1 over the last 30 years. Before the industrial revolution, rates of peat accumulation in all cores were much lower, at around 0.6-1 mm yr -1 . Carbon-13 discrimination (Δ), corrected for background and anthropogenic source inputs, was used to develop a predictive model for CO 2 assimilation. Between 1680 and 1900, there had been a gradual increase in Δ, and hence assimilation rate. Since 1800, assimilation has also been stimulated by the changes in atmospheric CO 2 concentration, but a recent decline in Δ (over the past 50-100 years) can perhaps be attributed to documented changes in temperature and/or precipitation. The overall increase in CO 2 assimilation rate ( 13 C proxy) and enhanced C accumulation ( 14 C proxy) are consistent with warmer and wetter conditions currently generating higher growth rates than at any time in the past three millennia, with the decline in Δ perhaps compensated by a longer growing season. © 2012 Blackwell Publishing Ltd.

  14. Four-hour quantitative real-time polymerase chain reaction-based comprehensive chromosome screening and accumulating evidence of accuracy, safety, predictive value, and clinical efficacy.

    PubMed

    Treff, Nathan R; Scott, Richard T

    2013-03-15

    Embryonic comprehensive chromosomal euploidy may represent a powerful biomarker to improve the success of IVF. However, there are a number of aneuploidy screening strategies to consider, including different technologic platforms with which to interrogate the embryonic DNA, and different embryonic developmental stages from which DNA can be analyzed. Although there are advantages and disadvantages associated with each strategy, a series of experiments producing evidence of accuracy, safety, clinical predictive value, and clinical efficacy indicate that trophectoderm biopsy and quantitative real-time polymerase chain reaction (qPCR)-based comprehensive chromosome screening (CCS) may represent a useful strategy to improve the success of IVF. This Biomarkers in Reproductive Medicine special issue review summarizes the accumulated experience with the development and clinical application of a 4-hour blastocyst qPCR-based CCS technology. Copyright © 2013 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  15. Extending the Reach of Evidence-Based Medicine: A Proposed Categorization of Lower-Level Evidence.

    PubMed

    Detterbeck, Frank C; Gould, Michael K; Lewis, Sandra Zelman; Patel, Sheena

    2018-02-01

    Clinical practice involves making many treatment decisions for which only limited formal evidence exists. While the methodology of evidence-based medicine (EBM) has evolved tremendously, there is a need to better characterize lower-level evidence. This should enhance the ability to appropriately weigh the evidence against other considerations, and counter the temptation to think it is more robust than it actually is. A framework to categorize lower-level evidence is proposed, consisting of nonrandomized comparisons, extrapolation using indirect evidence, rationale, and clinical experience (ie, an accumulated general impression). Subtypes are recognized within these categories, based on the degree of confounding in nonrandomized comparisons, the uncertainty involved in extrapolation from indirect evidence, and the plausibility of a rationale. Categorizing the available evidence in this way can promote a better understanding of the strengths and limitations of using such evidence as the basis for treatment decisions in clinically relevant areas that are devoid of higher-level evidence. Copyright © 2017 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.

  16. Accumulation of atmospheric sulfur in some Costa Rican soils

    USGS Publications Warehouse

    Bern, Carleton R.; Townsend, Alan R.

    2013-01-01

    Sulfur is one of the macronutrient elements whose sources to terrestrial ecosystems should shift from dominance by rock-weathering to atmospheric deposition as soils and underlying substrate undergo progressive weathering and leaching. However, the nature and timing of this transition is not well known. We investigated sources of sulfur to tropical rain forests growing on basalt-derived soils in the Osa Peninsula region of Costa Rica. Sulfur sources were examined using stable isotope ratios (δ34S) and compared to chemical indices of soil development. The most weathered soils, and the forests they supported, are dominated by atmospheric sulfur, while a less weathered soil type contains both rock-derived and atmospheric sulfur. Patterns of increasing δ34S with increasing soil sulfur concentration across the landscape suggest atmospheric sulfur is accumulating, and little rock-derived sulfur has been retained. Soil sulfur, minus adsorbed sulfate, is correlated with carbon and nitrogen, implying that sulfur accumulation occurs as plants and microbes incorporate sulfur into organic matter. Only the lower depth increments of the more weathered soils contained significant adsorbed sulfate. The evidence suggests a pattern of soil development in which sulfur-bearing minerals in rock, such as sulfides, weather early relative to other minerals, and the released sulfate is leached away. Sulfur added via atmospheric deposition is retained as organic matter accumulates in the soil profile. Adsorbed sulfate accumulates later, driven by changes in soil chemistry and mineralogy. These aspects of sulfur behavior during pedogenesis in this environment may hasten the transition to dominance by atmospheric sources.

  17. Evidence-based point-of-care tests and device designs for disaster preparedness.

    PubMed

    Brock, T Keith; Mecozzi, Daniel M; Sumner, Stephanie; Kost, Gerald J

    2010-01-01

    To define pathogen tests and device specifications needed for emerging point-of-care (POC) technologies used in disasters. Surveys included multiple-choice and ranking questions. Multiple-choice questions were analyzed with the chi2 test for goodness-of-fit and the binomial distribution test. Rankings were scored and compared using analysis of variance and Tukey's multiple comparison test. Disaster care experts on the editorial boards of the American Journal of Disaster Medicine and the Disaster Medicine and Public Health Preparedness, and the readers of the POC Journal. Vibrio cholera and Staphylococcus aureus were top-ranked pathogens for testing in disaster settings. Respondents felt that disaster response teams should be equipped with pandemic infectious disease tests for novel 2009 H1N1 and avian H5N1 influenza (disaster care, p < 0.05; POC, p < 0.01). In disaster settings, respondents preferred self-contained test cassettes (disaster care, p < 0.05; POC, p < 0.001) for direct blood sampling (POC, p < 0.01) and disposal of biological waste (disaster care, p < 0.05; POC, p < 0.001). Multiplex testing performed at the POC was preferred in urgent care and emergency room settings. Evidence-based needs assessment identifies pathogen detection priorities in disaster care scenarios, in which Vibrio cholera, methicillin-sensitive and methicillin-resistant Staphylococcus aureus, and Escherichia coli ranked the highest. POC testing should incorporate setting-specific design criteria such as safe disposable cassettes and direct blood sampling at the site of care.

  18. Using Structure-from-Motion to Quantify Sediment Accumulation and Bedrock Erosion in a Debris-Flow Dominated Channel

    NASA Astrophysics Data System (ADS)

    Reitman, N. G.; Rengers, F.; Kean, J. W.

    2016-12-01

    One of the highest frequencies of observed debris flows in the US is located at the Chalk Cliffs in central Colorado. This high rate of debris-flow activity ( 3 per year) is supported by a similarly high rate of sediment supply from rock fall and ravel due to frost weathering of the highly-erodible, hydrothermally-altered quartz monzonite cliffs during the winter months. A first step toward understanding debris-flow initiation, and channel and hillslope evolution, is to quantify the magnitude and spatial distribution of sediment that accumulates by the end of the winter period. Here we test the ability of structure-from-motion photogrammetric surveys to produce high-resolution point clouds in order to quantify sediment deposition, and possibly bedrock erosion. We use point clouds obtained from surveys conducted in late September 2015 and early June 2016 to measure sediment deposition in a 42-m-long channel over one winter. All surveys are co-registered with control points (screws drilled into bedrock) measured in a local coordinate system with a total station. Point clouds derived from these surveys have average point densities >200,000 pts/m2, and accuracies within 2 cm. Initial analysis shows accumulation of 10-50 cm ( 10 m3) of unconsolidated loose sediment over eight months, providing ample material for debris-flow initiation during the following summer season. Sediment accumulated in a spatially-variable pattern dependent on existing channel-bottom bedrock topography. Future surveys are planned in order to measure bedrock erosion by debris flows and variation in sediment deposition rate through time. Our analysis indicates that photogrammetric surveys provide a high level of detail at low cost, and thus are a useful geomorphic monitoring tool that will ultimately lead to better understanding of the processes that contribute to debris-flow activity and landscape evolution.

  19. NOX1-induced accumulation of reactive oxygen species in abdominal fat-derived mesenchymal stromal cells impinges on long-term proliferation

    PubMed Central

    Sela, M; Tirza, G; Ravid, O; Volovitz, I; Solodeev, I; Friedman, O; Zipori, D; Gur, E; Krelin, Y; Shani, N

    2015-01-01

    Mesenchymal stromal cells (MSCs) are multipotent and can be derived from different adult tissues including fat. Our repeated attempts to produce long-term proliferative cultures of rat abdominal adipose stem cells (aASCs) under normal oxygen concentration (21%) were unsuccessful. We set to examine the events controlling this cytostasis of aASCs and found that it resulted from overproduction of reactive oxygen species (ROS) that led to apoptosis. ROS overproduction in aASCs was accompanied by increased expression of NOX1 but not of NOX2 or NOX4. NOX family members are an important source of intracellular ROS pointing to NOX1 involvement in ROS accumulation. This was verified when aASCs that were grown under 3% oxygen conditions expanded long term, displaying reduced NOX1 expression and decreased ROS accumulation. NOX1 involvement in aASC cytostasis was reaffirmed when cells that were expanded under normoxic conditions in the presence of a specific NOX1 inhibitor, ML171, demonstrated reduced ROS accumulation, reduced apoptosis and long-term expansion. aASC expansion arrest was accompanied also by a weak fat differentiation and migratory potential, which was enhanced by NOX1 inhibition. This suggests an inhibitory role for NOX1-induced ROS overproduction on aASCs, their fat differentiation and migratory potential. In contrast to aASCs, similar cells produced from subcutaneous fat were easily expanded in normoxic cultures, exhibiting low ROS concentrations, a low number of apoptotic cells and improved fat differentiation and migration. Taken together, our results show, for the first time, that NOX1-induced ROS accumulation halts ASC expansion and reduces their differentiation and migratory potential under normoxic conditions. Importantly, this phenotype comprises a tissue-specific signature as it was evident in aASCs but not in subcutaneous ASCs. NOX-induced ROS accumulation and cytokine production by fat are part of the metabolic syndrome. The similarity of this

  20. [Evidence-based management of medical disposable materials].

    PubMed

    Yang, Hai

    2009-03-01

    Evidence-based management of medical disposable materials pays attention to collect evidence comprehensively and systematically, accumulate and create evidence through its own work and also evaluate evidence strictly. This can be used as a function to guide out job. Medical disposable materials evidence system contains product register qualification, product quality certification, supplier's behavior, internal and external communication evidence. Managers can find different ways in creating and using evidence referring to specific inside and outside condition. Evidence-based management can help accelerating the development of management of medical disposable materials from traditional experience pattern to a systematic and scientific pattern. It also has the very important meaning to improve medical quality, control the unreasonable growth of medical expense and make purchase and supply chain be more efficient.

  1. Ecological strategies of Al-accumulating and non-accumulating functional groups from the cerrado sensu stricto.

    PubMed

    Souza, Marcelo C de; Bueno, Paula C P; Morellato, Leonor P C; Habermann, Gustavo

    2015-01-01

    The cerrado's flora comprises aluminum-(Al) accumulating and non-accumulating plants, which coexist on acidic and Al-rich soils with low fertility. Despite their existence, the ecological importance or biological strategies of these functional groups have been little explored. We evaluated the leaf flushing patterns of both groups throughout a year; leaf concentrations of N, P, K, Ca, Mg, S, Al, total flavonoids and polyphenols; as well as the specific leaf area (SLA) on young and mature leaves within and between the groups. In Al-accumulating plants, leaf flushed throughout the year, mainly in May and September; for non-accumulating plants, leaf flushing peaked at the dry-wet seasons transition. However, these behaviors could not be associated with strategies for building up concentrations of defense compounds in leaves of any functional groups. Al-accumulating plants showed low leaf nutrient concentrations, while non-accumulating plants accumulated more macronutrients and produced leaves with high SLA since the juvenile leaf phase. This demonstrates that the increase in SLA is slower in Al-accumulating plants that are likely to achieve SLA values comparable to the rest of the plant community only in the wet season, when sunlight capture is important for the growth of new branches.

  2. Coulomb Stress Accumulation along the San Andreas Fault System

    NASA Technical Reports Server (NTRS)

    Smith, Bridget; Sandwell, David

    2003-01-01

    Stress accumulation rates along the primary segments of the San Andreas Fault system are computed using a three-dimensional (3-D) elastic half-space model with realistic fault geometry. The model is developed in the Fourier domain by solving for the response of an elastic half-space due to a point vector body force and analytically integrating the force from a locking depth to infinite depth. This approach is then applied to the San Andreas Fault system using published slip rates along 18 major fault strands of the fault zone. GPS-derived horizontal velocity measurements spanning the entire 1700 x 200 km region are then used to solve for apparent locking depth along each primary fault segment. This simple model fits remarkably well (2.43 mm/yr RMS misfit), although some discrepancies occur in the Eastern California Shear Zone. The model also predicts vertical uplift and subsidence rates that are in agreement with independent geologic and geodetic estimates. In addition, shear and normal stresses along the major fault strands are used to compute Coulomb stress accumulation rate. As a result, we find earthquake recurrence intervals along the San Andreas Fault system to be inversely proportional to Coulomb stress accumulation rate, in agreement with typical coseismic stress drops of 1 - 10 MPa. This 3-D deformation model can ultimately be extended to include both time-dependent forcing and viscoelastic response.

  3. Experimental evidence of zone-center optical phonon softening by accumulating holes in thin Ge

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

    Kabuyanagi, Shoichi; Nishimura, Tomonori; Yajima, Takeaki

    2016-01-15

    We discuss the impact of free carriers on the zone-center optical phonon frequency in germanium (Ge). By taking advantage of the Ge-on-insulator structure, we measured the Raman spectroscopy by applying back-gate bias. Phonon softening by accumulating holes in Ge film was clearly observed. This fact strongly suggests that the phonon softening in heavily-doped Ge is mainly attributed to the free carrier effect rather than the dopant atom counterpart. Furthermore, we propose that the free carrier effect on phonon softening is simply understandable from the viewpoint of covalent bonding modification by free carriers.

  4. Nonadditive protein accumulation patterns in Maize (Zea mays L.) hybrids during embryo development.

    PubMed

    Marcon, Caroline; Schützenmeister, André; Schütz, Wolfgang; Madlung, Johannes; Piepho, Hans-Peter; Hochholdinger, Frank

    2010-12-03

    Heterosis describes the superior performance of heterozygous F(1)-hybrid plants compared to their homozygous parental inbred lines. In the present study, heterosis was detected for length, weight, and the time point of seminal root primordia initiation in maize (Zea mays L.) embryos of the reciprocal F(1)-hybrids UH005xUH250 and UH250xUH005. A two-dimensional gel electrophoresis (2-DE) proteome survey of the most abundant proteins of the reciprocal hybrids and their parental inbred lines 25 and 35 days after pollination revealed that 141 of 597 detected proteins (24%) exhibited nonadditive accumulation in at least one hybrid. Approximately 44% of all nonadditively accumulated proteins displayed an expression pattern that was not distinguishable from the low parent value. Electrospray ionization-tandem mass spectrometry (ESI-MS/MS) analyses and subsequent functional classification of the 141 proteins revealed that development, protein metabolism, redox-regulation, glycolysis, and amino acid metabolism were the most prominent functional classes among nonadditively accumulated proteins. In 35-day-old embryos of the hybrid UH250xUH005, a significant up-regulation of enzymes related to glucose metabolism which often exceeded the best parent values was observed. A comparison of nonadditive protein accumulation between rice and maize embryo data sets revealed a significant overlap of nonadditively accumulated proteins suggesting conserved organ- or tissue-specific regulatory mechanisms in monocots related to heterosis.

  5. Uptake, accumulation and metabolization of the antidepressant fluoxetine by Mytilus galloprovincialis.

    PubMed

    Silva, Liliana J G; Martins, Margarida C; Pereira, André M P T; Meisel, Leonor M; Gonzalez-Rey, Maria; Bebianno, Maria João; Lino, Celeste M; Pena, Angelina

    2016-06-01

    Fluoxetine, a selective serotonin re-uptake inhibitor (SSRI) antidepressant, is among the most prescribed pharmaceutical active substances worldwide. This study aimed to assess its accumulation and metabolization in the mussel Mytillus galloprovincialis, considered an excellent sentinel species for traditional and emerging pollutants. Mussels were collected from Ria Formosa Lagoon, Portugal, and exposed to a nominal concentration of fluoxetine (75 ng L(-1)) for 15 days. Approximately 1 g of whole mussel soft tissues was extracted with acetonitrile:formic acid, loaded into an Oasis MCX cartridge, and fluoxetine analysed by liquid chromatography with tandem mass spectrometry (LC-MSn). After 3 days of exposure, fluoxetine was accumulated in 70% of the samples, with a mean of 2.53 ng g(-1) dry weight (d.w.) and norfluoxetine was only detected in one sample (10%), at 3.06 ng g(-1) d.w. After 7 days of exposure, the accumulation of fluoxetine and norfluoxetine increased up to 80 and 50% respectively, and their mean accumulated levels in mussel tissues were up to 4.43 and 2.85 ng g(-1) d.w., respectively. By the end of the exposure period (15 days), both compounds were detected in 100% of the samples (mean of 9.31 and 11.65 ng g(-1) d.w., respectively). Statistical analysis revealed significant accumulation differences between the 3rd and 15th day of exposure for fluoxetine, and between the 3rd and 7th against the 15th day of exposure for norfluoxetine. These results suggest that the fluoxetine accumulated in mussel tissues is likely to be metabolised into norfluoxetine with the increase of the time of exposure, giving evidence that at these realistic environmental concentrations, toxic effects of fluoxetine in mussel tissues may occur. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Effect of Hypergravity and Phytohormones on Isoflavonoid Accumulation in Soybean ( Glycine max. L.) Callus

    NASA Astrophysics Data System (ADS)

    Downey, Peter J.; Levine, Lanfang H.; Musgrave, Mary E.; McKeon-Bennett, Michelle; Moane, Siobhán

    2013-02-01

    The objective of this study was to explore the potential interaction between gravity and growth hormones on isoflavonoid accumulation. Soybean callus ( Glycine max (L.) Merr. cv. `Acme') was grown in the dark for 16 days at 22 °C in a growth medium supplemented with four different combinations of phytohormones and subjected to 4- g and 8- g forces simulated in a centrifuge and 1- g in an adjacent stationary control. Isoflavonoid aglycones and their glycoside concentrations (daidzein, genistein, daidzin, 6″-O-malonyl-7-O-glucosyl daidzein, genistin, 6″-O-malonyl-7-O-glucosyl genistein) were determined in the resulting tissues. Although gravity had no significant impact on callus growth, increasing gravity reduced isoflavonoid accumulation in three out of the four phytohormone-supplemented culture media. The ratio of the auxin naphthalene acetic acid (NAA) to the cytokinin benzylaminopurine (BAP) was found to have profound effect on both callus growth and isoflavonoid accumulation. The cytokinin BAP promoted callus tissue growth, but reduced callus isoflavonoid suggesting the isoflavonoid accumulation was not keeping pace with the cell growth in the elevated concentration of BAP. On the other hand, NAA had little or no effect on callus growth, but greatly enhanced isoflavonoid accumulation. Interactive effects of gravity and hormone on isoflavonoid accumulation were evident and its implication to the mechanism by which gravity exerts the effect on plant secondary metabolites is discussed.

  7. Continuous and Episodic Modern Sediment Accumulation on Monterey Fan: Evidence from Ddt, 137Cs and Excess 210Pb

    NASA Astrophysics Data System (ADS)

    Gwiazda, R.; Paull, C. K.; Alexander, C. R.; Ussler, W.

    2012-12-01

    The mode and magnitude of fine-grained sediment accumulation on the Monterey Fan off the California central coast was investigated using pesticide concentrations and radioactive tracer profiles in sediment cores. DDT is a man-made pesticide that was used extensively in central California between 1945 and 1970. As such, its presence in marine sediments is a telltale sign of a modern sedimentation age. DDT and its metabolites, DDE and DDD, (collectively referred to as DDTr) were measured in fifty-five ~20cm-long sediment cores collected from the surface of the Monterey Fan up to 250 km to the south and 210 km to the west of the Monterey Canyon head, and in four transects across the Monterey Canyon channel at maximum water depths of 3160, 3380, 3580, and 3880 meters. Profiles of excess 210Pb (210Pbxs) and 137Cs were measured in 5 cores from the Fan to estimate recent sedimentation rates. Detectable levels of DDTr were observed in all but one of these cores, with DDTr concentrations characteristically highest at the surface and decreasing with depth. The area-normalized and depth-integrated DDTr content measured in all the cores in the Fan and in the deepest two channel transects was geographically fairly homogenous, with no statistical relationship between DDTr inventory and distance from the main channel crossing the Fan. The total sediment mass deposited on the Fan over the last 60 years, inferred from the total inventory of DDTr present in the area surveyed, is consistent with the amount of sediment delivered by the Salinas River over the same time period. 210Pbxs activities are fairly homogeneous within an uppermost layer of variable thickness (4.6-8cm) and decrease exponentially below it, but these exponential decreases are often interrupted by horizons with constant or increased 210Pbxs activity. Moreover, the coexistence of variable DDTr concentrations with homogeneous 210Pbxs activities in the top sediment indicates that the uniformity of 210Pbxs is not due

  8. Is Beta-Amyloid Accumulation a Cause or Consequence of Alzheimer’s Disease?

    PubMed Central

    Wang, Shaoxun; Mims, Paige N.; Roman, Richard J.; Fan, Fan

    2017-01-01

    Alzheimer’s disease (AD) is a progressive neurodegenerative disorder that is characterized by the pathological hallmarks of extracellular beta-amyloid (Aβ) plaques and intraneuronal tau-containing neurofibrillary tangles in the brain. Intraneuronal accumulation of Aβ also plays a role to accelerate AD progression by promoting neurodegeneration. Additionally, AD is associated with the development of amyloid angiopathy (CAA), in which Aβ builds up on the walls of the cerebral arteries, which augments the development of cerebral vascular disease (CVD). Conversely, CVD promotes Aβ deposition and the development of AD by affecting the balance of Aβ production and clearance. However, it remains to be determined whether the accumulation of Aβ is a cause or consequence of AD. The interaction between AD and CVD is a topic of considerable current interest. Here, we discuss the role of CVD in Aβ accumulation and the development of AD to provide a new point of view that combination therapies that address the accompanying cerebral microvascular disease may potentiate the efficacy of emerging treatment for AD. PMID:28815226

  9. Hydroxynonenal-generated crosslinking fluorophore accumulation in Alzheimer disease reveals a dichotomy of protein turnover.

    PubMed

    Zhu, Xiongwei; Castellani, Rudy J; Moreira, Paula I; Aliev, Gjumrakch; Shenk, Justin C; Siedlak, Sandra L; Harris, Peggy L R; Fujioka, Hisashi; Sayre, Lawrence M; Szweda, Pamela A; Szweda, Luke I; Smith, Mark A; Perry, George

    2012-02-01

    Lipid peroxidation generates reactive aldehydes, most notably hydroxynonenal (HNE), which covalently bind amino acid residue side chains leading to protein inactivation and insolubility. Specific adducts of lipid peroxidation have been demonstrated in intimate association with the pathological lesions of Alzheimer disease (AD), suggesting that oxidative stress is a major component of AD pathogenesis. Some HNE-protein products result in protein crosslinking through a fluorescent compound similar to lipofuscin, linking lipid peroxidation and the lipofuscin accumulation that commonly occurs in post-mitotic cells such as neurons. In this study, brain tissue from AD and control patients was examined by immunocytochemistry and immunoelectron microscopy for evidence of HNE-crosslinking modifications of the type that should accumulate in the lipofuscin pathway. Strong labeling of granulovacuolar degeneration (GVD) and Hirano bodies was noted but lipofuscin did not contain this specific HNE-fluorophore. These findings directly implicate lipid crosslinking peroxidation products as accumulating not in the lesions or the lipofuscin pathways, but instead in a distinct pathway, GVD, that accumulates cytosolic proteins. Copyright © 2011 Elsevier Inc. All rights reserved.

  10. A lee-side eddy and its influence on snow accumulation

    NASA Astrophysics Data System (ADS)

    Gerber, Franziska; Mott, Rebecca; Hoch, Sebastian W.; Lehning, Michael

    2016-04-01

    Knowledge of changes in seasonal mountain snow water resources is essential for e.g. hydropower companies. To successfully predict these changes a fundamental understanding of precipitation patterns and their changes in mountainous terrain is needed. Both, snow accumulation and ablation need to be investigated to make precise predictions of the amount of water stored in seasonal snow cover. Only if the processes governing snow accumulation and ablation are understood with sufficient quantitative accuracy, the evolution of snow water resources under a changing climate can be addressed. Additionally, knowledge of detailed snow accumulation patterns is essential to assess avalanche danger. In alpine terrain, snow accumulation is strongly dependent on the local wind field. Based on the concept of preferential deposition, reduced snow accumulation is expected on the upper windward slope of a mountain due to updrafts, while enhanced snow accumulation should occur through blocking at the windward foot or due to flow separation on the leeward side. However, the understanding of these processes is mainly based on numerical simulations, as they are hard to measure. A LiDAR (Light Detection And Ranging) campaign was conducted in October 2015 in the Dischma valley (Davos, CH) to investigate the local flow field in the lee of the Sattelhorn during a one-day snowfall event. The flow field was monitored using a plane position indicator (PPI) scan at 25/28° and a range height indicator (RHI) scan across the Sattelhorn. Additionally, snow height change measurements on the leeward side of the Sattelhorn were performed by terrestrial laser scanning (TLS). Analyses of the flow field in the framework of preferential deposition are in agreement with the concept of flow separation and preferred snow deposition on leeward slopes. A very persistent eddy that formed over the leeward slope of the Sattelhorn detached from the main flow became evident from the retrievals of the RHI scans. An

  11. 150,000 years of loess accumulation in central Alaska

    NASA Astrophysics Data System (ADS)

    Jensen, Britta J. L.; Evans, Michael E.; Froese, Duane G.; Kravchinsky, Vadim A.

    2016-03-01

    The Halfway House site in interior Alaska is arguably the most studied loess deposit in northwestern North America. The site contains a complex paleomagnetic and paleoenvironmental record, but has lacked the robust chronologic control that would allow its full potential to be exploited. Detailed reexamination of stratigraphy, paleomagnetics and tephrostratigraphy reveals a relatively complete marine isotope stage (MIS) 6 to Holocene record constrained by the Old Crow (124 ± 10 ka), VT (106 ± 10 ka), Sheep Creek-Klondike (ca. 80 ka), Dominion Creek (77 ± 8 ka) and Dawson (ca. 30.2 cal ka BP) tephras. We show two well-developed paleosols formed during Marine Isotope Stages (MIS) 5e and 5a, while MIS 5c and 5b are either poorly represented or absent. The new tephrostratigraphy presented here is the most complete one to date for the late Pleistocene and indicates MIS 5 sediments are more common than previously recognized. A magnetic excursion within the sediments is identified as the post-Blake excursion (94.1 ± 7.8 ka), providing independent age control and adding to the increasing body of evidence that Alaskan loess is a detailed recorder of variations of the Earth's magnetic field over time. A high-resolution magnetic susceptibility profile placed into this new chronostratigraphic framework supports the hypothesis that wind-intensity is the main variable controlling fluctuations in susceptibility. Correlation of the susceptibility record to global marine δ18O records is complicated by highly variable accumulation rates. We find the lowest rates of accumulation during peak warm and cold stages, while abrupt increases are associated with periods of transition between marine isotope (sub)stages. Building on previous accumulation models for Alaska, surface roughness is likely a leading variable controlling loess accumulation rates during transitions and peak cold periods, but the negligible accumulation during MIS 5e and 5a suggests that loess production was

  12. Facilitating admissions of diverse students: A six-point, evidence-informed framework for pipeline and program development.

    PubMed

    Young, Meredith E; Thomas, Aliki; Varpio, Lara; Razack, Saleem I; Hanson, Mark D; Slade, Steve; Dayem, Katharine L; McKnight, David J

    2017-04-01

    Several national level calls have encouraged reconsideration of diversity issues in medical education. Particular interest has been placed on admissions, as decisions made here shape the nature of the future physician workforce. Critical analysis of current practices paired with evidence-informed policies may counter some of the barriers impeding access for underrepresented groups. We present a framework for diversity-related program development and evaluation grounded within a knowledge translation framework, and supported by the initiation of longitudinal collection of diversity-related data. We provide an illustrative case study for each component of the framework. Descriptive analyses are presented of pre/post intervention diversity metrics if applicable and available. The framework's focal points are: 1) data-driven identification of underrepresented groups, 2) pipeline development and targeted recruitment, 3) ensuring an inclusive process, 4) ensuring inclusive assessment, 5) ensuring inclusive selection, and 6) iterative use of diversity-related data. Case studies ranged from wording changes on admissions websites to the establishment of educational and administrative offices addressing needs of underrepresented populations. We propose that diversity-related data must be collected on a variety of markers, developed in partnership with stakeholders who are most likely to facilitate implementation of best practices and new policies. These data can facilitate the design, implementation, and evaluation of evidence-informed diversity initiatives and provide a structure for continued investigation into 'interventions' supporting diversity-related initiatives.

  13. The accumulation and localization of chalcone synthase in grapevine (Vitis vinifera L.).

    PubMed

    Wang, Huiling; Wang, Wei; Zhan, JiCheng; Yan, Ailing; Sun, Lei; Zhang, Guojun; Wang, Xiaoyue; Ren, Jiancheng; Huang, Weidong; Xu, Haiying

    2016-09-01

    Chalcone synthase (CHS, E.C.2.3.1.74) is the first committed enzyme in the flavonoid pathway. Previous studies have primarily focused on the cloning, expression and regulation of the gene at the transcriptional level. Little is yet known about the enzyme accumulation, regulation at protein level, as well as its localization in grapevine. In present study, the accumulation, tissue and subcellular localization of CHS in different grapevine tissues (Vitis vinifera L. Cabernet Sauvignon) were investigated via the techniques of Western blotting, immunohistochemical localization, immunoelectron microscopy and confocal microscopy. The results showed that CHS were mainly accumulated in the grape berry skin, leaves, stem tips and stem phloem, correlated with flavonoids accumulation. The accumulation of CHS is developmental dependent in grape berry skin and flesh. Immunohistochemical analysis revealed that CHS were primarily localized in the exocarp and vascular bundles of the fruits during berry development; in palisade, spongy tissues and vascular bundles of the leaves; in the primary phloem and pith ray in the stems; in the growth point, leaf primordium, and young leaves of leaf buds; and in the endoderm and primary phloem of grapevine roots. Furthermore, at the subcellular level, the cell wall, cytoplasm and nucleus localized patterns of CHS were observed in the grapevine vegetative tissue cells. Results above indicated that distribution of CHS in grapevine was organ-specific and tissue-specific. This work will provide new insight for the biosynthesis and regulation of diverse flavonoid compounds in grapevine. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  14. Management of chronic recurrent osteitis pubis/pubic bone stress in a Premier League footballer: Evaluating the evidence base and application of a nine-point management strategy.

    PubMed

    McAleer, Stephen S; Gille, Justus; Bark, Stefan; Riepenhof, Helge

    2015-08-01

    The aim of this paper was to use a clinical example to describe a treatment strategy for the management of recurrent chronic groin pain and evaluate the evidence of the interventions. A professional footballer presented with chronic recurrent OP/PBS. The injury was managed successfully with a nine-point programme - 1. Acute pharmacological management. 2. Tone reduction of over-active structures. 3. Improved ROM at hips, pelvis and thorax. 4. Adductor strength. 5. Functional movement assessment. 6. Core stability. 7. Lumbo-pelvic control. 8. Gym-based strengthening. 9. Field-based conditioning/rehabilitation. The evidence for these interventions is reviewed. The player returned to full training and match play within 41 and 50 days, respectively, and experienced no recurrence of his symptoms in follow up at 13 months. This case report displays a nine-point conservative management strategy for OP/PBS, with non-time dependent clinical objective markers as the progression criteria in a Premier League football player. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. A patient with type I CD36 deficiency whose myocardium accumulated 123I-BMIPP after 4 years.

    PubMed

    Ito, K; Sugihara, H; Tanabe, T; Zen, K; Hikosaka, T; Adachi, Y; Katoh, S; Azuma, A; Nakagawa, M

    2001-06-01

    A 73-year-old man with aortic regurgitation was examined by 123I-alpha-methyl-p-iodophenylpentadecanoic acid (BMIPP) myocardial single photon emission computed tomography (SPECT) in 1995. Myocardial accumulation was not evident on either the early or the delayed image obtained 15 minutes and 3 hours, respectively, after injecting 123I-BMIPP. Flow cytometric analysis of CD36 expression in monocytes and platelets identified a type I CD36 deficiency. The patient was hospitalized for severe heart failure in 1999. Upon admission, the cardiothoracic ratio on chest X-rays was 73%, and the left ventricular end-diastolic diameter on echocardiograms was enlarged to 77 mm. On the second day, we performed 123I-BMIPP myocardial SPECT. Myocardial accumulation was evident in the delayed, but not in the early image. We repeated 123I-BMIPP myocardial SPECT on the 10th day after admission. Myocardial accumulation was evident on both early and delayed images. 99mTc-tetrofosmin myocardial SPECT was immediately performed after 123I-BMIPP myocardial SPECT to distinguish myocardial from pooling images in the left ventricle, but, because the images from both 99Tc-tetrofosmin and 123I-BMIPP myocardial SPECT were idential, we considered that the 123I-BMIPP myocardial SPECT images reflected the actual myocardial condition. The CD36 molecule transports long-chain fatty acid (LCFA) on the myocardial membrane, but 123I-BMIPP scintigraphy does not show any myocardial accumulation in patients with type I CD36 deficiency, indicating that myocardial LCFA uptake occurs through CD36 on the human myocardial membrane. Even though our patient had type I CD36 deficiency, BMIPP was uptaken by the myocardium during heart failure, suggesting a variant pathway on the human myocardial membrane for LCFA uptake.

  16. Soil and biomass carbon re-accumulation after landslide disturbances

    NASA Astrophysics Data System (ADS)

    Schomakers, Jasmin; Jien, Shih-Hao; Lee, Tsung-Yu; Huang-Chuan, Jr.; Hseu, Zeng-Yei; Lin, Zan Liang; Lee, Li-Chin; Hein, Thomas; Mentler, Axel; Zehetner, Franz

    2017-07-01

    In high-standing islands of the Western Pacific, typhoon-triggered landslides occasionally strip parts of the landscape of its vegetative cover and soil layer and export large amounts of biomass and soil organic carbon (OC) from land to the ocean. After such disturbances, new vegetation colonizes the landslide scars and OC starts to re-accumulate. In the subtropical mountains of Taiwan and in other parts of the world, bamboo (Bambusoideae) species may invade at a certain point in the succession of recovering landslide scars. Bamboo has a high potential for carbon sequestration because of its fast growth and dense rooting system. However, it is still largely unknown how these properties translate into soil OC re-accumulation rates after landslide disturbance. In this study, a chronosequence was established on four former landslide scars in the Central Mountain Range of Taiwan, ranging in age from 6 to 41 years post disturbance as determined by landslide mapping from remote sensing. The younger landslide scars were colonized by Miscanthus floridulus, while after approx. 15 to 20 years of succession, bamboo species (Phyllostachys) were dominating. Biomass and soil OC stocks were measured on the recovering landslide scars and compared to an undisturbed Cryptomeria japonica forest stand in the area. After initially slow re-vegetation, biomass carbon accumulated in Miscanthus stands with mean annual accretion rates of 2 ± 0.5 Mg C ha- 1 yr- 1. Biomass carbon continued to increase after bamboo invasion and reached 40% of that in the reference forest site after 41 years of landslide recovery. Soil OC accumulation rates were 2.0 Mg C ha- 1 yr- 1, 6 to 41 years post disturbance reaching 64% of the level in the reference forest. Our results from this in-situ study suggest that recovering landslide scars are strong carbon sinks once an initial lag period of vegetation re-establishment is overcome.

  17. Death rates reflect accumulating brain damage in arthropods.

    PubMed

    Fonseca, Duane B; Brancato, Carolina L; Prior, Andrew E; Shelton, Peter M J; Sheehy, Matt R J

    2005-09-22

    We present the results of the first quantitative, whole-lifespan study of the relationship between age-specific neurolipofuscin concentration and natural mortality rate in any organism. In a convenient laboratory animal, the African migratory locust, Locusta migratoria, we find an unusual delayed-onset neurolipofuscin accumulation pattern that is highly correlated with exponentially accelerating age-specific Gompertz-Makeham death rates in both males (r=0.93, p=0.0064) and females (r=0.97, p=0.0052). We then test the conservation of this association by aggregating the locust results with available population-specific data for a range of other terrestrial, freshwater, marine, tropical and temperate arthropods whose longevities span three orders of magnitude. This synthesis shows that the strong association between neurolipofuscin deposition and natural mortality is a phylogenetically and environmentally widespread phenomenon (r=0.96, p < 0.0001). These results highlight neurolipofuscin as a unique and outstanding integral biomarker of ageing. They also offer compelling evidence for the proposal that, in vital organs like the brain, either the accumulation of toxic garbage in the form of lipofuscin itself, or the particular molecular reactions underlying lipofuscinogenesis, including free-radical damage, are the primary events in senescence.

  18. Turning Knowledge Into Action at the Point-of-Care: The Collective Experience of Nurses Facilitating the Implementation of Evidence-Based Practice

    PubMed Central

    Dogherty, Elizabeth J; Harrison, Margaret B; Graham, Ian D; Vandyk, Amanda Digel; Keeping-Burke, Lisa

    2013-01-01

    -based practice in real situations at the point-of-care. With a greater understanding of factors contributing to successful or unsuccessful facilitation, future research should focus on analyzing facilitation interventions tailored to address barriers and enhance facilitators of evidence uptake. PMID:23796066

  19. HIV populations are large and accumulate high genetic diversity in a nonlinear fashion.

    PubMed

    Maldarelli, Frank; Kearney, Mary; Palmer, Sarah; Stephens, Robert; Mican, JoAnn; Polis, Michael A; Davey, Richard T; Kovacs, Joseph; Shao, Wei; Rock-Kress, Diane; Metcalf, Julia A; Rehm, Catherine; Greer, Sarah E; Lucey, Daniel L; Danley, Kristen; Alter, Harvey; Mellors, John W; Coffin, John M

    2013-09-01

    HIV infection is characterized by rapid and error-prone viral replication resulting in genetically diverse virus populations. The rate of accumulation of diversity and the mechanisms involved are under intense study to provide useful information to understand immune evasion and the development of drug resistance. To characterize the development of viral diversity after infection, we carried out an in-depth analysis of single genome sequences of HIV pro-pol to assess diversity and divergence and to estimate replicating population sizes in a group of treatment-naive HIV-infected individuals sampled at single (n = 22) or multiple, longitudinal (n = 11) time points. Analysis of single genome sequences revealed nonlinear accumulation of sequence diversity during the course of infection. Diversity accumulated in recently infected individuals at rates 30-fold higher than in patients with chronic infection. Accumulation of synonymous changes accounted for most of the diversity during chronic infection. Accumulation of diversity resulted in population shifts, but the rates of change were low relative to estimated replication cycle times, consistent with relatively large population sizes. Analysis of changes in allele frequencies revealed effective population sizes that are substantially higher than previous estimates of approximately 1,000 infectious particles/infected individual. Taken together, these observations indicate that HIV populations are large, diverse, and slow to change in chronic infection and that the emergence of new mutations, including drug resistance mutations, is governed by both selection forces and drift.

  20. Adipocyte differentiation-related protein promotes lipid accumulation in goat mammary epithelial cells.

    PubMed

    Shi, H B; Yu, K; Luo, J; Li, J; Tian, H B; Zhu, J J; Sun, Y T; Yao, D W; Xu, H F; Shi, H P; Loor, J J

    2015-10-01

    Milk fat originates from the secretion of cytosolic lipid droplets (CLD) synthesized within mammary epithelial cells. Adipocyte differentiation-related protein (ADRP; gene symbol PLIN2) is a CLD-binding protein that is crucial for synthesis of mature CLD. Our hypothesis was that ADRP regulates CLD production and metabolism in goat mammary epithelial cells (GMEC) and thus plays a role in determining milk fat content. To understand the role of ADRP in ruminant milk fat metabolism, ADRP (PLIN2) was overexpressed or knocked down in GMEC using an adenovirus system. Immunocytochemical staining revealed that ADRP localized to the surface of CLD. Supplementation with oleic acid (OA) enhanced its colocalization with CLD surface and enhanced lipid accumulation. Overexpression of ADRP increased lipid accumulation and the concentration of triacylglycerol in GMEC. In contrast, morphological examination revealed that knockdown of ADRP decreased lipid accumulation even when OA was supplemented. This response was confirmed by the reduction in mass of cellular TG when ADRP was knocked down. The fact that knockdown of ADRP did not completely eliminate lipid accumulation at a morphological level in GMEC without OA suggests that some other compensatory factors may also aid in the process of CLD formation. The ADRP reversed the decrease of CLD accumulation induced by adipose triglyceride lipase. This is highly suggestive of ADRP promoting triacylglycerol stability within CLD by preventing access to adipose triglyceride lipase. Collectively, these data provide direct in vitro evidence that ADRP plays a key role in CLD formation and stability in GMEC. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  1. Coordinated within-trial dynamics of low-frequency neural rhythms controls evidence accumulation.

    PubMed

    Werkle-Bergner, Markus; Grandy, Thomas H; Chicherio, Christian; Schmiedek, Florian; Lövdén, Martin; Lindenberger, Ulman

    2014-06-18

    Higher cognitive functions, such as human perceptual decision making, require information processing and transmission across wide-spread cortical networks. Temporally synchronized neural firing patterns are advantageous for efficiently representing and transmitting information within and between assemblies. Computational, empirical, and conceptual considerations all lead to the expectation that the informational redundancy of neural firing rates is positively related to their synchronization. Recent theorizing and initial evidence also suggest that the coding of stimulus characteristics and their integration with behavioral goal states require neural interactions across a hierarchy of timescales. However, most studies thus have focused on neural activity in a single frequency range or on a restricted set of brain regions. Here we provide evidence for cooperative spatiotemporal dynamics of slow and fast EEG signals during perceptual decision making at the single-trial level. Participants performed three masked two-choice decision tasks, one each with numerical, verbal, or figural content. Decrements in posterior α power (8-14 Hz) were paralleled by increments in high-frequency (>30 Hz) signal entropy in trials demanding active sensory processing. Simultaneously, frontocentral θ power (4-7 Hz) increased, indicating evidence integration. The coordinated α/θ dynamics were tightly linked to decision speed and remarkably similar across tasks, suggesting a domain-general mechanism. In sum, we demonstrate an inverse association between decision-related changes in widespread low-frequency power and local high-frequency entropy. The cooperation among mechanisms captured by these changes enhances the informational density of neural response patterns and qualifies as a neural coding system in the service of perceptual decision making. Copyright © 2014 the authors 0270-6474/14/348519-10$15.00/0.

  2. Evaluation of short-chain-length polyhydroxyalkanoate accumulation in Bacillus aryabhattai.

    PubMed

    Balakrishna Pillai, Aneesh; Jaya Kumar, Arjun; Thulasi, Kavitha; Kumarapillai, Harikrishnan

    This study was focused on the polyhydroxybutyrate (PHB) accumulation property of Bacillus aryabhattai isolated from environment. Twenty-four polyhydroxyalkanoate (PHA) producers were screened out from sixty-two environmental bacterial isolates based on Sudan Black B colony staining. Based on their PHA accumulation property, six promising isolates were further screened out. The most productive isolate PHB10 was identified as B. aryabhattai PHB10. The polymer production maxima were 3.264g/L, 2.181g/L, 1.47g/L, 1.742g/L and 1.786g/L in glucose, fructose, maltose, starch and glycerol respectively. The bacterial culture reached its stationary and declining phases at 18h and 21h respectively and indicated growth-associated PHB production. Nuclear Magnetic Resonance (NMR) spectra confirmed the material as PHB. The material has thermal stability between 30 and 140°C, melting point at 170°C and maximum thermal degradation at 287°C. The molecular weight and poly dispersion index of the polymer were found as 199.7kDa and 2.67 respectively. The bacterium B. aryabhattai accumulating PHB up to 75% of cell dry mass utilizing various carbon sources is a potential candidate for large scale production of bacterial polyhydroxybutyrate. Copyright © 2017 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

  3. Carotenoid accumulation in orange-pigmented Capsicum annuum fruit, regulated at multiple levels.

    PubMed

    Rodriguez-Uribe, Laura; Guzman, Ivette; Rajapakse, Wathsala; Richins, Richard D; O'Connell, Mary A

    2012-01-01

    The pericarp of Capsicum fruit is a rich dietary source of carotenoids. Accumulation of these compounds may be controlled, in part, by gene transcription of biosynthetic enzymes. The carotenoid composition in a number of orange-coloured C. annuum cultivars was determined using HPLC and compared with transcript abundances for four carotenogenic enzymes, Psy, LcyB, CrtZ-2, and Ccs determined by qRT-PCR. There were unique carotenoid profiles as well as distinct patterns of transcription of carotenogenic enzymes within the seven orange-coloured cultivars. In one cultivar, 'Fogo', carrying the mutant ccs-3 allele, transcripts were detected for this gene, but no CCS protein accumulated. The premature stop termination in ccs-3 prevented expression of the biosynthetic activity to synthesize the capsanthin and capsorubin forms of carotenoids. In two other orange-coloured cultivars, 'Orange Grande' and 'Oriole', both with wild-type versions of all four carotenogenic enzymes, no transcripts for Ccs were detected and no red pigments accumulated. Finally, in a third case, the orange-coloured cultivar, Canary, transcripts for all four of the wild-type carotenogenic enzymes were readily detected yet no CCS protein appeared to accumulate and no red carotenoids were synthesized. In the past, mutations in Psy and Ccs have been identified as the loci controlling colour in the fruit. Now there is evidence that a non-structural gene may control colour development in Capsicum.

  4. LSAH: a fast and efficient local surface feature for point cloud registration

    NASA Astrophysics Data System (ADS)

    Lu, Rongrong; Zhu, Feng; Wu, Qingxiao; Kong, Yanzi

    2018-04-01

    Point cloud registration is a fundamental task in high level three dimensional applications. Noise, uneven point density and varying point cloud resolutions are the three main challenges for point cloud registration. In this paper, we design a robust and compact local surface descriptor called Local Surface Angles Histogram (LSAH) and propose an effectively coarse to fine algorithm for point cloud registration. The LSAH descriptor is formed by concatenating five normalized sub-histograms into one histogram. The five sub-histograms are created by accumulating a different type of angle from a local surface patch respectively. The experimental results show that our LSAH is more robust to uneven point density and point cloud resolutions than four state-of-the-art local descriptors in terms of feature matching. Moreover, we tested our LSAH based coarse to fine algorithm for point cloud registration. The experimental results demonstrate that our algorithm is robust and efficient as well.

  5. Neurodegeneration with Brain Iron Accumulation

    MedlinePlus

    ... are here Home » Disorders » All Disorders Neurodegeneration with Brain Iron Accumulation Information Page Neurodegeneration with Brain Iron Accumulation Information Page What research is being ...

  6. Constant-Differential-Pressure Two-Fluid Accumulator

    NASA Technical Reports Server (NTRS)

    Piecuch, Benjamin; Dalton, Luke T.

    2010-01-01

    A two-fluid accumulator has been designed, built, and demonstrated to provide an acceptably close approximation to constant differential static pressure between two fluids over the full ranges of (1) accumulator stroke, (2) rates of flow of the fluids, and (3) common static pressure applied to the fluids. Prior differential- pressure two-fluid accumulators are generally not capable of maintaining acceptably close approximations to constant differential pressures. The inadequacies of a typical prior differential-pressure two-fluid accumulator can be summarized as follows: The static differential pressure is governed by the intrinsic spring rate (essentially, the stiffness) of an accumulator tank. The spring rate can be tailored through selection of the tank-wall thickness, selection of the number and/or shape of accumulator convolutions, and/or selection of accumulator material(s). Reliance on the intrinsic spring rate of the tank results in three severe limitations: (1) The spring rate and the expulsion efficiency tend to be inversely proportional to each other: that is to say, as the stiffness (and thus the differential pressure) is increased, the range of motion of the accumulator is reduced. (2) As the applied common static pressure increases, the differential pressure tends to decrease. An additional disadvantage, which may or may not be considered limiting, depending on the specific application, is that an increase in stiffness entails an increase in weight. (3) The additional weight required by a low expulsion efficiency accumulator eliminates the advantage given to such gas storage systems. The high expulsion efficiency provided by this two-fluid accumulator allows for a lightweight, tightly packaged system, which can be used in conjunction with a fuel cell-based system.

  7. Free cholesterol accumulation impairs antioxidant activities and aggravates apoptotic cell death in menadione-induced oxidative injury.

    PubMed

    Lee, Waisin; Xu, Mingjing; Li, Yue; Gu, Yong; Chen, Jianping; Wong, Derek; Fung, Peter C W; Shen, Jiangang

    2011-10-01

    Although the relationship between hypercholesterolemia and oxidative stress has been extensively investigated, direct evidence regarding to the roles of cholesterol accumulation in the generations of reactive oxygen species (ROS) and apoptotic cell death under oxidative stress is lack. In this study, we investigated productions of superoxide anions (O(2)(-)) and nitric oxide (NO), and apoptotic cell death in wild type Chinese hamster ovary (CHO) cells and cholesterol accumulated CHO cells genetically and chemically. Oxidative stress was induced by menadione challenge. The results revealed that abundance of free cholesterol (FC) promoted menadione-induced O(2)(-) and NO productions. FC accumulation down-regulated eNOS expression but up-regulated NADPH oxidases, and inhibited the activities of superoxide dismutase (SOD) and catalase. Treatment of menadione increased the expressions of iNOS and qp91 phox, enhanced the activities of SOD and catalase in the wild-type CHO cells but inhibited the activity of glutathione peroxidase in the cholesterol accumulated CHO cells. Moreover, FC abundance promoted apoptotic cell death in these cells. Taken together, those results suggest that free cholesterol accumulation aggravates menadione-induced oxidative stress and exacerbates apoptotic cell death. Copyright © 2011 Elsevier Inc. All rights reserved.

  8. The accumulation of brain injury leads to severe neuropathological and neurobehavioral changes after repetitive mild traumatic brain injury.

    PubMed

    Gao, Huabin; Han, Zhaoli; Bai, Ruojing; Huang, Shan; Ge, Xintong; Chen, Fanglian; Lei, Ping

    2017-02-15

    Traumatic brain injury (TBI) is a major public health problem with long-term neurobehavioral sequela. The evidences have revealed that TBI is a risk factor for later development of neurodegenerative disease and both the single and repetitive brain injury can lead to the neurodegeneration. But whether the effects of accumulation play an important role in the neurodegenerative disease is still unknown. We utilized the Sprague Dawley (SD) rats to develop the animal models of repetitive mild TBI and single mild TBI in order to detect the neurobehavioral changes. The results of neurobehavioral test revealed that the repetitive mild TBI led to more severe behavioral injuries than the single TBI. There were more activated microglia cells and astrocytes in the repetitive mild TBI group than the single TBI group. In consistent with this, the levels of TNF-α and IL-6 were higher and the expression of IL-10 was lower in the repetitive mild TBI group compared with the single TBI group. The expression of amyloid precursor protein (APP) increased in the repetitive TBI group detected by ELISA and western blot. But the levels of total tau (Tau-5) and P-tau (ser202) seem no different between the two groups in most time point. In conclusion, repetitive mild TBI could lead to more severe neurobehavioral impairments and the effects of accumulation may be associated with the increased inflammation in the brain. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. An Ecological Tipping Point Defined by Shallow Marine Foraminifera in the latest Paleocene

    NASA Astrophysics Data System (ADS)

    Robinson, M. M.; Spivey, W.

    2016-12-01

    The Paleocene-Eocene Thermal Maximum (PETM) is recognized in marine sediments by a carbonate dissolution zone, the extinction or turnover of benthic taxa, and a radiation of planktic excursion taxa, all accompanied by a rapid-onset, negative carbon isotope excursion (CIE). We present foraminiferal evidence from shallow marine sediments in southeastern Maryland, USA, where accumulation rates are high, for a minor ocean acidification event in the latest Paleocene that coincides with a relatively small (-2‰) CIE. This pre-onset excursion (POE) precedes the larger (-4‰) PETM CIE onset and dissolution event. During the POE, the benthic assemblage is reconfigured toward agglutinated species in order to adapt to increased acidity, and the planktic assemblage begins to speciate due to perturbed mixed layer conditions. The benthic assemblage returns to normal, without interruption, as the POE recovers, but planktic excursion taxa continue to appear in very low numbers. This is contrasted to the major ocean acidification event associated with the PETM CIE onset that results in a zone of complete dissolution followed by distinctive benthic and planktic foraminiferal assemblages. Our microfossil evidence documents a biotic response to bottom water and mixed layer perturbations that illustrates how coastal ecosystems react to both moderate and severe ocean acidification events, bracketing the ecological tipping point of shallow marine ecosystems. The POE, roughly half the magnitude of the CIE onset, provides insight into the nature of the initial effects of climate perturbation as well as an example of one that is fully recoverable. It is here that research aimed to better understand the long-term effects and reversibility of modern deteriorating oceanic conditions should focus. This study provides an initial metric by which to measure modern ecosystem disturbances and will help to define the tipping point for the shallow marine environment.

  10. Mapping the accumulation of co-infiltrating CNS dendritic cells and encephalitogenic T cells during EAE

    PubMed Central

    Clarkson, Benjamin D; Walker, Alec; Harris, Melissa; Rayasam, Aditya; Sandor, Matyas; Fabry, Zsuzsanna

    2014-01-01

    Evidence from experimental autoimmune encephalomyelitis (EAE) suggests that CNS-infiltrating dendritic cells (DCs) are crucial for restimulation of coinfiltrating T cells. Here we systematically quantified and visualized the distribution and interaction of CNS DCs and T cells during EAE. We report marked periventricular accumulation of DCs and myelin-specific T cells during EAE disease onset prior to accumulation in the spinal cord, indicating that the choroid plexus-CSF axis is a CNS entry portal. Moreover, despite emphasis on spinal cord inflammation in EAE and in correspondence with MS pathology, inflammatory lesions containing interacting DCs and T cells are present in specific brain regions. PMID:25288303

  11. Spatiotemporal patterns of mercury accumulation in lake sediments of western North America

    USGS Publications Warehouse

    Drevnick, Paul; Cooke, Colin A.; Barraza, Daniella; Blais, Jules M.; Coale, Kenneth; Cumming, Brian F.; Curtis, Chris; Das, Biplob; Donahue, William F.; Eagles-Smith, Collin A.; Engstrom, Daniel R.; Fitzgerald, William F.; Furl, Chad V.; Gray, John R.; Hall, Roland I.; Jackson, Togwell A.; Laird, Kathleen R.; Lockhart, W. Lyle; Macdonald, Robie W.; Mast, M. Alisa; Mathieu, Callie; Muir, Derek C.G.; Outridge, Peter; Reinemann, Scott; Rothenberg, Sarah E.; Ruiz-Fernandex, Ana Carolina; St. Louis, V.L.; Sanders, Rhea; Sanei, Hamed; Skierszkan, Elliott; Van Metre, Peter C.; Veverica, Timothy; Wiklund, Johan A.; Wolfe, Brent B.

    2016-01-01

    For the Western North America Mercury Synthesis, we compiled mercury records from 165 dated sediment cores from 138 natural lakes across western North America. Lake sediments are accepted as faithful recorders of historical mercury accumulation rates, and regional and sub-regional temporal and spatial trends were analyzed with descriptive and inferential statistics. Mercury accumulation rates in sediments have increased, on average, four times (4×) from 1850 to 2000 and continue to increase by approximately 0.2 μg/m2 per year. Lakes with the greatest increases were influenced by the Flin Flon smelter, followed by lakes directly affected by mining and wastewater discharges. Of lakes not directly affected by point sources, there is a clear separation in mercury accumulation rates between lakes with no/little watershed development and lakes with extensive watershed development for agricultural and/or residential purposes. Lakes in the latter group exhibited a sharp increase in mercury accumulation rates with human settlement, stabilizing after 1950 at five times (5×) 1850 rates. Mercury accumulation rates in lakes with no/little watershed development were controlled primarily by relative watershed size prior to 1850, and since have exhibited modest increases (in absolute terms and compared to that described above) associated with (regional and global) industrialization. A sub-regional analysis highlighted that in the ecoregion Northwestern Forest Mountains, <1% of mercury deposited to watersheds is delivered to lakes. Research is warranted to understand whether mountainous watersheds act as permanent sinks for mercury or if export of “legacy” mercury (deposited in years past) will delay recovery when/if emissions reductions are achieved.

  12. Accumulation of organic compounds leached from plastic materials used in biopharmaceutical process containers.

    PubMed

    Jenke, Dennis R; Zietlow, David; Garber, Mary Jo; Sadain, Salma; Reiber, Duane; Terbush, William

    2007-01-01

    Plastic materials are widely used in medical items, such as solution containers, transfusion sets, transfer tubing, and devices. An emerging trend in the biotechnology industry is the utilization of plastic containers to prepare, transport, and store an assortment of solutions including buffers, media, and in-process and finished product. The direct contact of such containers with the product at one or more points in its lifetime raises the possibility that container leachables may accumulate in the finished product. The interaction between several commercially available container materials and numerous model test solutions (representative of buffers and media used in biopharmaceutical applications) was investigated. This paper summarizes the identification of leachables associated with the container materials and documents the levels to which targeted leachables accumulate in the test solutions under defined storage conditions.

  13. Incipient triple point for adsorbed xenon monolayers: Pt(111) versus graphite substrates

    NASA Astrophysics Data System (ADS)

    Novaco, Anthony D.; Bruch, L. W.; Bavaresco, Jessica

    2015-04-01

    Simulation evidence of an incipient triple point is reported for xenon submonolayers adsorbed on the (111) surface of platinum. This is in stark contrast to the "normal" triple point found in simulations and experiments for xenon on the basal plane surface of graphite. The motions of the atoms in the surface plane are treated with standard 2D "NVE" molecular dynamics simulations using modern interactions. The simulation evidence strongly suggests an incipient triple point in the 120 -150 K range for adsorption on the Pt (111) surface while the adsorption on graphite shows a normal triple point at about 100 K.

  14. Dynamically encircling an exceptional point for asymmetric mode switching.

    PubMed

    Doppler, Jörg; Mailybaev, Alexei A; Böhm, Julian; Kuhl, Ulrich; Girschik, Adrian; Libisch, Florian; Milburn, Thomas J; Rabl, Peter; Moiseyev, Nimrod; Rotter, Stefan

    2016-09-01

    Physical systems with loss or gain have resonant modes that decay or grow exponentially with time. Whenever two such modes coalesce both in their resonant frequency and their rate of decay or growth, an 'exceptional point' occurs, giving rise to fascinating phenomena that defy our physical intuition. Particularly intriguing behaviour is predicted to appear when an exceptional point is encircled sufficiently slowly, such as a state-flip or the accumulation of a geometric phase. The topological structure of exceptional points has been experimentally explored, but a full dynamical encircling of such a point and the associated breakdown of adiabaticity have remained out of reach of measurement. Here we demonstrate that a dynamical encircling of an exceptional point is analogous to the scattering through a two-mode waveguide with suitably designed boundaries and losses. We present experimental results from a corresponding waveguide structure that steers incoming waves around an exceptional point during the transmission process. In this way, mode transitions are induced that transform this device into a robust and asymmetric switch between different waveguide modes. This work will enable the exploration of exceptional point physics in system control and state transfer schemes at the crossroads between fundamental research and practical applications.

  15. Civil Conflict and Human Capital Accumulation: The Long-Term Effects of Political Violence in Peru

    ERIC Educational Resources Information Center

    Leon, Gianmarco

    2012-01-01

    This paper provides empirical evidence of the persistent effect of exposure to political violence on human capital accumulation. I exploit the variation in conflict location and birth cohorts to identify the long- and short-term effects of the civil war on educational attainment. Conditional on being exposed to violence, the average person…

  16. When Do Infants Begin to Follow a Point?

    ERIC Educational Resources Information Center

    Bertenthal, Bennett I.; Boyer, Ty W.; Harding, Samuel

    2014-01-01

    Infants' understanding of a pointing gesture represents a major milestone in their communicative development. The current consensus is that infants are not capable of following a pointing gesture until 9-12 months of age. In this article, we present evidence from 4- and 6-month-old infants challenging this conclusion. Infants were tested with…

  17. Breast cancer risk accumulation starts early: prevention must also.

    PubMed

    Colditz, Graham A; Bohlke, Kari; Berkey, Catherine S

    2014-06-01

    Nearly one in four breast cancers is diagnosed before the age of 50, and many early-stage premalignant lesions are present but not yet diagnosed. Therefore, we review evidence to support the strategy that breast cancer prevention efforts must begin early in life. This study follows the literature review methods and format. Exposures during childhood and adolescence affect a woman's long-term risk of breast cancer, but have received far less research attention than exposures that occur later in life. Breast tissue undergoes rapid cellular proliferation between menarche and first full-term pregnancy, and risk accumulates rapidly until the terminal differentiation that accompanies first pregnancy. Evidence on childhood diet and growth in height, and adolescent alcohol intake, among other adolescent factors is related to breast cancer risk and risk of premalignant proliferative benign lesions. Breast cancer prevention efforts will have the greatest effect when initiated at an early age and continued over a lifetime. Gaps in knowledge are identified and deserve increase attention to inform prevention.

  18. Expanded Study on the accumulation effect of tourism under the constraint of structure

    NASA Astrophysics Data System (ADS)

    Wang, Qiang; Yang, Zhenzhi; Huang, Lu

    2017-05-01

    There is a mutual influence between departmental structure and accumulation and growth. Therefore, the accumulation and growth of the tourism industry will be subject to certain restrictions on the industrial structure, and, conversely, it will have an impact on the existing industrial structure. Li Jingyi reported special research in the paper called "Research on tourism growth based on structural constraints" about the relationship between the growth of tourism and the existing industrial structure. It pointed out the specific interdependence between tourism and other economic sectors in terms of accumulation and growth. However, the research of Li Jingyi is based on the trichotomy of social product value. It is too abstract, while the study is understandable in theory. In practice, it is difficult to use the model of the paper to deal with specific problems. Therefore, how to improve the industry association model in the paper of Li and make it more in line with the actual situation becomes our concern. In this paper, the author hopes to improve the model of Li's paper by simplifying the decomposition of social product value. At the same time, it makes a further study on accumulation elasticity and growth elasticity. On this basis, some suggestions are put forward to guide the development of other industries based on the tourism industry.

  19. Social skills interventions for individuals with autism: evaluation for evidence-based practices within a best evidence synthesis framework.

    PubMed

    Reichow, Brian; Volkmar, Fred R

    2010-02-01

    This paper presents a best evidence synthesis of interventions to increase social behavior for individuals with autism. Sixty-six studies published in peer-reviewed journals between 2001 and July 2008 with 513 participants were included. The results are presented by the age of the individual receiving intervention and by delivery agent of intervention. The findings suggest there is much empirical evidence supporting many different treatments for the social deficits of individuals with autism. Using the criteria of evidence-based practice proposed by Reichow et al. (Journal of Autism and Developmental Disorders, 38:1311-1318, 2008), social skills groups and video modeling have accumulated the evidence necessary for the classifications of established EBP and promising EBP, respectively. Recommendations for practice and areas of future research are provided.

  20. Whole Genome Re-Sequencing Identifies a Quantitative Trait Locus Repressing Carbon Reserve Accumulation during Optimal Growth in Chlamydomonas reinhardtii

    PubMed Central

    Goold, Hugh Douglas; Nguyen, Hoa Mai; Kong, Fantao; Beyly-Adriano, Audrey; Légeret, Bertrand; Billon, Emmanuelle; Cuiné, Stéphan; Beisson, Fred; Peltier, Gilles; Li-Beisson, Yonghua

    2016-01-01

    Microalgae have emerged as a promising source for biofuel production. Massive oil and starch accumulation in microalgae is possible, but occurs mostly when biomass growth is impaired. The molecular networks underlying the negative correlation between growth and reserve formation are not known. Thus isolation of strains capable of accumulating carbon reserves during optimal growth would be highly desirable. To this end, we screened an insertional mutant library of Chlamydomonas reinhardtii for alterations in oil content. A mutant accumulating five times more oil and twice more starch than wild-type during optimal growth was isolated and named constitutive oil accumulator 1 (coa1). Growth in photobioreactors under highly controlled conditions revealed that the increase in oil and starch content in coa1 was dependent on light intensity. Genetic analysis and DNA hybridization pointed to a single insertional event responsible for the phenotype. Whole genome re-sequencing identified in coa1 a >200 kb deletion on chromosome 14 containing 41 genes. This study demonstrates that, 1), the generation of algal strains accumulating higher reserve amount without compromising biomass accumulation is feasible; 2), light is an important parameter in phenotypic analysis; and 3), a chromosomal region (Quantitative Trait Locus) acts as suppressor of carbon reserve accumulation during optimal growth. PMID:27141848

  1. Biota-Sediment Accumulation Factor Data

    EPA Pesticide Factsheets

    The Biota-Sediment Accumulation Factor contains approximately 20,000 biota-sediment accumulation factors (BSAFs) from 20 locations (mostly Superfund sites) for nonionic organic chemicals and pesticides. Fresh, tidal, and marine ecosystems are included in the data.

  2. Evidence for Precursors of the Coronal Hole Jets in Solar Bright Points

    NASA Astrophysics Data System (ADS)

    Bagashvili, Salome R.; Shergelashvili, Bidzina M.; Japaridze, Darejan R.; Kukhianidze, Vasil; Poedts, Stefaan; Zaqarashvili, Teimuraz V.; Khodachenko, Maxim L.; De Causmaecker, Patrick

    2018-03-01

    A set of 23 observations of coronal jet events that occurred in coronal bright points has been analyzed. The focus was on the temporal evolution of the mean brightness before and during coronal jet events. In the absolute majority of the cases either single or recurrent coronal jets (CJs) were preceded by slight precursor disturbances observed in the mean intensity curves. The key conclusion is that we were able to detect quasi-periodical oscillations with characteristic periods from sub-minute up to 3–4 minute values in the bright point brightness that precedes the jets. Our basic claim is that along with the conventionally accepted scenario of bright-point evolution through new magnetic flux emergence and its reconnection with the initial structure of the bright point and the coronal hole, certain magnetohydrodynamic (MHD) oscillatory and wavelike motions can be excited and these can take an important place in the observed dynamics. These quasi-oscillatory phenomena might play the role of links between different epochs of the coronal jet ignition and evolution. They can be an indication of the MHD wave excitation processes due to the system entropy variations, density variations, or shear flows. It is very likely a sharp outflow velocity transverse gradients at the edges between the open and closed field line regions. We suppose that magnetic reconnections can be the source of MHD waves due to impulsive generation or rapid temperature variations, and shear flow driven nonmodel MHD wave evolution (self-heating and/or overreflection mechanisms).

  3. Carotenoid accumulation in orange-pigmented Capsicum annuum fruit, regulated at multiple levels

    PubMed Central

    Rodriguez-Uribe, Laura; Guzman, Ivette; Rajapakse, Wathsala; Richins, Richard D.; O’Connell, Mary A.

    2012-01-01

    The pericarp of Capsicum fruit is a rich dietary source of carotenoids. Accumulation of these compounds may be controlled, in part, by gene transcription of biosynthetic enzymes. The carotenoid composition in a number of orange-coloured C. annuum cultivars was determined using HPLC and compared with transcript abundances for four carotenogenic enzymes, Psy, LcyB, CrtZ-2, and Ccs determined by qRT-PCR. There were unique carotenoid profiles as well as distinct patterns of transcription of carotenogenic enzymes within the seven orange-coloured cultivars. In one cultivar, ‘Fogo’, carrying the mutant ccs-3 allele, transcripts were detected for this gene, but no CCS protein accumulated. The premature stop termination in ccs-3 prevented expression of the biosynthetic activity to synthesize the capsanthin and capsorubin forms of carotenoids. In two other orange-coloured cultivars, ‘Orange Grande’ and ‘Oriole’, both with wild-type versions of all four carotenogenic enzymes, no transcripts for Ccs were detected and no red pigments accumulated. Finally, in a third case, the orange-coloured cultivar, Canary, transcripts for all four of the wild-type carotenogenic enzymes were readily detected yet no CCS protein appeared to accumulate and no red carotenoids were synthesized. In the past, mutations in Psy and Ccs have been identified as the loci controlling colour in the fruit. Now there is evidence that a non-structural gene may control colour development in Capsicum. PMID:21948863

  4. Massive accumulation of luminal protease-deficient axonal lysosomes at Alzheimer's disease amyloid plaques.

    PubMed

    Gowrishankar, Swetha; Yuan, Peng; Wu, Yumei; Schrag, Matthew; Paradise, Summer; Grutzendler, Jaime; De Camilli, Pietro; Ferguson, Shawn M

    2015-07-14

    Through a comprehensive analysis of organellar markers in mouse models of Alzheimer's disease, we document a massive accumulation of lysosome-like organelles at amyloid plaques and establish that the majority of these organelles reside within swollen axons that contact the amyloid deposits. This close spatial relationship between axonal lysosome accumulation and extracellular amyloid aggregates was observed from the earliest stages of β-amyloid deposition. Notably, we discovered that lysosomes that accumulate in such axons are lacking in multiple soluble luminal proteases and thus are predicted to be unable to efficiently degrade proteinaceous cargos. Of relevance to Alzheimer's disease, β-secretase (BACE1), the protein that initiates amyloidogenic processing of the amyloid precursor protein and which is a substrate for these proteases, builds up at these sites. Furthermore, through a comparison between the axonal lysosome accumulations at amyloid plaques and neuronal lysosomes of the wild-type brain, we identified a similar, naturally occurring population of lysosome-like organelles in neuronal processes that is also defined by its low luminal protease content. In conjunction with emerging evidence that the lysosomal maturation of endosomes and autophagosomes is coupled to their retrograde transport, our results suggest that extracellular β-amyloid deposits cause a local impairment in the retrograde axonal transport of lysosome precursors, leading to their accumulation and a blockade in their further maturation. This study both advances understanding of Alzheimer's disease brain pathology and provides new insights into the subcellular organization of neuronal lysosomes that may have broader relevance to other neurodegenerative diseases with a lysosomal component to their pathology.

  5. Modelling past, present and future peatland carbon accumulation across the pan-Arctic region

    NASA Astrophysics Data System (ADS)

    Chaudhary, Nitin; Miller, Paul A.; Smith, Benjamin

    2017-09-01

    Most northern peatlands developed during the Holocene, sequestering large amounts of carbon in terrestrial ecosystems. However, recent syntheses have highlighted the gaps in our understanding of peatland carbon accumulation. Assessments of the long-term carbon accumulation rate and possible warming-driven changes in these accumulation rates can therefore benefit from process-based modelling studies. We employed an individual-based dynamic global ecosystem model with dynamic peatland and permafrost functionalities and patch-based vegetation dynamics to quantify long-term carbon accumulation rates and to assess the effects of historical and projected climate change on peatland carbon balances across the pan-Arctic region. Our results are broadly consistent with published regional and global carbon accumulation estimates. A majority of modelled peatland sites in Scandinavia, Europe, Russia and central and eastern Canada change from carbon sinks through the Holocene to potential carbon sources in the coming century. In contrast, the carbon sink capacity of modelled sites in Siberia, far eastern Russia, Alaska and western and northern Canada was predicted to increase in the coming century. The greatest changes were evident in eastern Siberia, north-western Canada and in Alaska, where peat production hampered by permafrost and low productivity due the cold climate in these regions in the past was simulated to increase greatly due to warming, a wetter climate and higher CO2 levels by the year 2100. In contrast, our model predicts that sites that are expected to experience reduced precipitation rates and are currently permafrost free will lose more carbon in the future.

  6. Tissue accumulation of microplastics in mice and biomarker responses suggest widespread health risks of exposure

    NASA Astrophysics Data System (ADS)

    Deng, Yongfeng; Zhang, Yan; Lemos, Bernardo; Ren, Hongqiang

    2017-04-01

    Microplastics (MPs) are a significant environmental health issue and increasingly greater source of concern. MPs have been detected in oceans, rivers, sediments, sewages, soil and even table salts. MPs exposure on marine organisms and humans has been documented, but information about the toxicity of MPs in mammal is limited. Here we used fluorescent and pristine polystyrene microplastics (PS-MPs) particles with two diameters (5 μm and 20 μm) to investigate the tissue distribution, accumulation, and tissue-specific health risk of MPs in mice. Results indicated that MPs accumulated in liver, kidney and gut, with a tissue-accumulation kinetics and distribution pattern that was strongly depended on the MPs particle size. In addition, analyses of multiple biochemical biomarkers and metabolomic profiles suggested that MPs exposure induced disturbance of energy and lipid metabolism as well as oxidative stress. Interestingly, blood biomarkers of neurotoxicity were also altered. Our results uncovered the distribution and accumulation of MPs across mice tissues and revealed significant alteration in several biomarkers that indicate potential toxicity from MPs exposure. Collectively, our data provided new evidence for the adverse consequences of MPs.

  7. Tissue accumulation of microplastics in mice and biomarker responses suggest widespread health risks of exposure

    PubMed Central

    Deng, Yongfeng; Zhang, Yan; Lemos, Bernardo; Ren, Hongqiang

    2017-01-01

    Microplastics (MPs) are a significant environmental health issue and increasingly greater source of concern. MPs have been detected in oceans, rivers, sediments, sewages, soil and even table salts. MPs exposure on marine organisms and humans has been documented, but information about the toxicity of MPs in mammal is limited. Here we used fluorescent and pristine polystyrene microplastics (PS-MPs) particles with two diameters (5 μm and 20 μm) to investigate the tissue distribution, accumulation, and tissue-specific health risk of MPs in mice. Results indicated that MPs accumulated in liver, kidney and gut, with a tissue-accumulation kinetics and distribution pattern that was strongly depended on the MPs particle size. In addition, analyses of multiple biochemical biomarkers and metabolomic profiles suggested that MPs exposure induced disturbance of energy and lipid metabolism as well as oxidative stress. Interestingly, blood biomarkers of neurotoxicity were also altered. Our results uncovered the distribution and accumulation of MPs across mice tissues and revealed significant alteration in several biomarkers that indicate potential toxicity from MPs exposure. Collectively, our data provided new evidence for the adverse consequences of MPs. PMID:28436478

  8. Influence of salinity and organic matter on silver accumulation in Gulf toadfish (Opsanus beta).

    PubMed

    Nichols, Joel W; Brown, Stephanie; Wood, Chris M; Walsh, Patrick J; Playle, Richard C

    2006-06-30

    To help extend the freshwater based biotic ligand model for silver (Ag) into brackish and saltwater conditions, 50g Gulf toadfish (Opsanus beta) were acclimated to 2.5%, 5%, 10%, 20%, 40%, 80%, or 100% salt water and exposed for 6d to 1.0microM AgNO(3), with or without 10mg C/L organic matter. Suwannee River natural organic matter collected by reverse osmosis was used. Silver accumulation in toadfish gills and plasma decreased as salinity increased, indicating low bioavailability of AgCl complexes. Complexation of Ag by organic matter, normally important in freshwater conditions, was less important as salinity increased. Although relatively little intestinal Ag uptake was observed, both liver and bile accumulated Ag from water imbibed past the isosmotic salinity point ( approximately 1/3 salt water). Toadfish also produced intestinal carbonate pellets, minerals which did not influence Ag accumulation. Our results further stress the importance of Ag speciation, physiological mechanisms, and intestinal Ag uptake when modelling Ag uptake and toxicity beyond freshwater conditions.

  9. Choice Rules and Accumulator Networks

    PubMed Central

    2015-01-01

    This article presents a preference accumulation model that can be used to implement a number of different multi-attribute heuristic choice rules, including the lexicographic rule, the majority of confirming dimensions (tallying) rule and the equal weights rule. The proposed model differs from existing accumulators in terms of attribute representation: Leakage and competition, typically applied only to preference accumulation, are also assumed to be involved in processing attribute values. This allows the model to perform a range of sophisticated attribute-wise comparisons, including comparisons that compute relative rank. The ability of a preference accumulation model composed of leaky competitive networks to mimic symbolic models of heuristic choice suggests that these 2 approaches are not incompatible, and that a unitary cognitive model of preferential choice, based on insights from both these approaches, may be feasible. PMID:28670592

  10. Understanding reduced inorganic mercury accumulation in rice following selenium application: Selenium application routes, speciation and doses.

    PubMed

    Tang, Wenli; Dang, Fei; Evans, Douglas; Zhong, Huan; Xiao, Lin

    2017-02-01

    Selenium (Se) has recently been demonstrated to reduce inorganic mercury (IHg) accumulation in rice plants, while its mechanism is far from clear. Here, we aimed at exploring the potential effects of Se application routes (soil or foliar application with Se), speciation (selenite and selenate), and doses on IHg-Se antagonistic interactions in soil-rice systems. Results of our pot experiments indicated that soil application but not foliar application could evidently reduce tissue IHg concentrations (root: 0-48%, straw: 15-58%, and brown rice: 26-74%), although both application routes resulted in comparable Se accumulation in aboveground tissues. Meanwhile, IHg distribution in root generally increased with amended Se doses in soil, suggesting antagonistic interactions between IHg and Se in root. These results provided initial evidence that IHg-Se interactions in the rhizosphere (i.e., soil or rice root), instead of those in the aboveground tissues, could probably be more responsible for the reduced IHg bioaccumulation following Se application. Furthermore, Se dose rather than Se speciation was found to be more important in controlling IHg accumulation in rice. Our findings regarding the importance of IHg-Se interactions in the rhizosphere, together with the systematic investigation of key factors affecting IHg-Se antagonism and IHg bioaccumulation, advance our understanding of Hg dynamics in soil-rice systems. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Modeling snow accumulation and ablation processes in forested environments

    NASA Astrophysics Data System (ADS)

    Andreadis, Konstantinos M.; Storck, Pascal; Lettenmaier, Dennis P.

    2009-05-01

    The effects of forest canopies on snow accumulation and ablation processes can be very important for the hydrology of midlatitude and high-latitude areas. A mass and energy balance model for snow accumulation and ablation processes in forested environments was developed utilizing extensive measurements of snow interception and release in a maritime mountainous site in Oregon. The model was evaluated using 2 years of weighing lysimeter data and was able to reproduce the snow water equivalent (SWE) evolution throughout winters both beneath the canopy and in the nearby clearing, with correlations to observations ranging from 0.81 to 0.99. Additionally, the model was evaluated using measurements from a Boreal Ecosystem-Atmosphere Study (BOREAS) field site in Canada to test the robustness of the canopy snow interception algorithm in a much different climate. Simulated SWE was relatively close to the observations for the forested sites, with discrepancies evident in some cases. Although the model formulation appeared robust for both types of climates, sensitivity to parameters such as snow roughness length and maximum interception capacity suggested the magnitude of improvements of SWE simulations that might be achieved by calibration.

  12. Accumulation of senescent cells in mitotic tissue of aging primates.

    PubMed

    Jeyapalan, Jessie C; Ferreira, Mark; Sedivy, John M; Herbig, Utz

    2007-01-01

    Cellular senescence, a stress induced growth arrest of somatic cells, was first documented in cell cultures over 40 years ago, however its physiological significance has only recently been demonstrated. Using novel biomarkers of cellular senescence we examined whether senescent cells accumulate in tissues from baboons of ages encompassing the entire lifespan of this species. We show that dermal fibroblasts, displaying markers of senescence such as telomere damage, active checkpoint kinase ATM, high levels of heterochromatin proteins and elevated levels of p16, accumulate in skin biopsies from baboons with advancing age. The number of dermal fibroblasts containing damaged telomeres reaches a value of over 15% of total fibroblasts, whereas 80% of cells contain high levels of the heterochromatin protein HIRA. In skeletal muscle, a postmitotic tissue, only a small percentage of myonuclei containing damaged telomeres were detected regardless of animal age. The presence of senescent cells in mitotic tissues might therefore be a contributing factor to aging and age related pathology and provides further evidence that cellular senescence is a physiological event.

  13. Accumulation of Senescent Cells in Mitotic Tissue of Aging Primates

    PubMed Central

    Jeyapalan, Jessie C.; Ferreira, Mark; Sedivy, John M.; Herbig, Utz

    2013-01-01

    Cellular senescence, a stress induced growth arrest of somatic cells, was first documented in cell cultures over forty years ago, however its physiological significance has only recently been demonstrated. Using novel biomarkers of cellular senescence we examined whether senescent cells accumulate in tissues from baboons of ages encompassing the entire lifespan of this species. We show that dermal fibroblasts, displaying markers of senescence such as telomere damage, active checkpoint kinase ATM, high levels of heterochromatin proteins and elevated levels of p16, accumulate in skin biopsies from baboons with advancing age. The number of dermal fibroblasts containing damaged telomeres reaches a value of over 15% of total fibroblasts, whereas 80% of cells contain high levels of the heterochromatin protein HIRA. In skeletal muscle, a postmitotic tissue, only a small percentage of myonuclei containing damaged telomeres were detected regardless of animal age. The presence of senescent cells in mitotic tissues might therefore be a contributing factor to aging and age related pathology and provides further evidence that cellular senescence is a physiological event. PMID:17116315

  14. Therapeutic Targeting of Eosinophil Adhesion and Accumulation in Allergic Conjunctivitis

    PubMed Central

    Baiula, Monica; Bedini, Andrea; Carbonari, Gioia; Dattoli, Samantha Deianira; Spampinato, Santi

    2012-01-01

    Considerable evidence indicates that eosinophils are important effectors of ocular allergy. Increased worldwide prevalence of allergic eye pathologies has stimulated the identification of novel drug targets, including eosinophils and adhesion molecules. Accumulation of eosinophils in the eye is a key event in the onset and maintenance of allergic inflammation and is mediated by different adhesion molecules. Antihistamines with multiple mechanisms of action can be effective during the early and late phases of allergic conjunctivitis by blocking the interaction between β1 integrins and vascular cell adhesion molecule (VCAM)-1. Small molecule antagonists that target key elements in the process of eosinophil recruitment have been identified and reinforce the validity of α4β1 integrin as a therapeutic target. Glucocorticoids are among the most effective drugs for ocular allergy, but their use is limited by adverse effects. Novel dissociated glucocorticoids can prevent eosinophil accumulation and induce apoptosis of eosinophils, making them promising candidates for ophthalmic drugs. This article reviews recent understanding of the role of adhesion molecules in eosinophil recruitment in the inflamed conjunctiva along with effective treatments for allergic conjunctivitis. PMID:23271999

  15. Evidence of low-density and high-density liquid phases and isochore end point for water confined to carbon nanotube

    PubMed Central

    Nomura, Kentaro; Kaneko, Toshihiro; Bai, Jaeil; Francisco, Joseph S.; Yasuoka, Kenji; Zeng, Xiao Cheng

    2017-01-01

    Possible transition between two phases of supercooled liquid water, namely the low- and high-density liquid water, has been only predicted to occur below 230 K from molecular dynamics (MD) simulation. However, such a phase transition cannot be detected in the laboratory because of the so-called “no-man’s land” under deeply supercooled condition, where only crystalline ices have been observed. Here, we show MD simulation evidence that, inside an isolated carbon nanotube (CNT) with a diameter of 1.25 nm, both low- and high-density liquid water states can be detected near ambient temperature and above ambient pressure. In the temperature–pressure phase diagram, the low- and high-density liquid water phases are separated by the hexagonal ice nanotube (hINT) phase, and the melting line terminates at the isochore end point near 292 K because of the retracting melting line from 292 to 278 K. Beyond the isochore end point (292 K), low- and high-density liquid becomes indistinguishable. When the pressure is increased from 10 to 600 MPa along the 280-K isotherm, we observe that water inside the 1.25-nm-diameter CNT can undergo low-density liquid to hINT to high-density liquid reentrant first-order transitions. PMID:28373562

  16. How to Say "No" to a Nonword: A Leaky Competing Accumulator Model of Lexical Decision

    ERIC Educational Resources Information Center

    Dufau, Stephane; Grainger, Jonathan; Ziegler, Johannes C.

    2012-01-01

    We describe a leaky competing accumulator (LCA) model of the lexical decision task that can be used as a response/decision module for any computational model of word recognition. The LCA model uses evidence for a word, operationalized as some measure of lexical activity, as input to the "YES" decision node. Input to the "NO" decision node is…

  17. Validation of non-rigid point-set registration methods using a porcine bladder pelvic phantom

    NASA Astrophysics Data System (ADS)

    Zakariaee, Roja; Hamarneh, Ghassan; Brown, Colin J.; Spadinger, Ingrid

    2016-01-01

    The problem of accurate dose accumulation in fractionated radiotherapy treatment for highly deformable organs, such as bladder, has garnered increasing interest over the past few years. However, more research is required in order to find a robust and efficient solution and to increase the accuracy over the current methods. The purpose of this study was to evaluate the feasibility and accuracy of utilizing non-rigid (affine or deformable) point-set registration in accumulating dose in bladder of different sizes and shapes. A pelvic phantom was built to house an ex vivo porcine bladder with fiducial landmarks adhered onto its surface. Four different volume fillings of the bladder were used (90, 180, 360 and 480 cc). The performance of MATLAB implementations of five different methods were compared, in aligning the bladder contour point-sets. The approaches evaluated were coherent point drift (CPD), gaussian mixture model, shape context, thin-plate spline robust point matching (TPS-RPM) and finite iterative closest point (ICP-finite). The evaluation metrics included registration runtime, target registration error (TRE), root-mean-square error (RMS) and Hausdorff distance (HD). The reference (source) dataset was alternated through all four points-sets, in order to study the effect of reference volume on the registration outcomes. While all deformable algorithms provided reasonable registration results, CPD provided the best TRE values (6.4 mm), and TPS-RPM yielded the best mean RMS and HD values (1.4 and 6.8 mm, respectively). ICP-finite was the fastest technique and TPS-RPM, the slowest.

  18. Sediment focusing creates 100-ka cycles in interplanetary dust accumulation on the Ontong Java Plateau

    NASA Astrophysics Data System (ADS)

    Higgins, Sean M.; Anderson, Robert F.; Marcantonio, Franco; Schlosser, Peter; Stute, Martin

    2002-10-01

    The accumulation of extraterrestrial 3He, a tracer for interplanetary dust particles (IDPs), in sediments from the Ontong Java Plateau (OJP; western equatorial Pacific Ocean) has been shown previously to exhibit a regular cyclicity during the late Pleistocene, with a period of ∼100 ka. Those results have been interpreted to reflect periodic variability in the global accretion of IDPs that, in turn, has been linked to changes in the inclination of Earth's orbit with respect to the invariable plane of the solar system. Here we show that the accumulation in OJP sediments of authigenic 230Th, produced by radioactive decay of 234U in seawater, exhibits a 100-ka cyclicity similar in phase and amplitude to that evident in the 3He record. We interpret the similar patterns of 230Th and 3He accumulation to reflect a common origin within the ocean-climate system. Comparing spatial and temporal patterns of sediment accumulation against regional patterns of biological productivity and against the well-established pattern of CaCO3 dissolution in the deep Pacific Ocean leads to the further conclusion that a common 100-ka cycle in accumulation of biogenic, authigenic and extraterrestrial constituents in OJP sediments reflects the influence of climate-related changes in sediment focusing, rather than changes in the rate of production or supply of sedimentary constituents.

  19. Determination of trunk streams via using flow accumulation values

    NASA Astrophysics Data System (ADS)

    Farek, Vladimir

    2013-04-01

    There is often a problem, with schematisation of catchments and a channel networks in a broken relief like sandstone landscape (with high vertical segmentation, narrow valley lines, crags, sheer rocks, endorheic hollows etc.). Usual hydrological parameters (subcatchment areas, altitude of highest point of subcatchment, water discharge), which are mostly used for determination of trunk stream upstream the junction, are frequently not utilizable very well in this kind of relief. We found, that for small, relatively homogeneous catchments (within the meaning of land-use, geological subsurface, anthropogenic influence etc.), which are extremely shaped, the value called "flow accumulation" (FA) could be very useful. This value gives the number of cells of the Digital Elevation Model (DEM) grid, which are drained to each cell of the catchment. We can predict that the stream channel with higher values of flow accumulation represents the main stream. There are three crucial issues with this theory. At first it is necessary to find the most suitable algorithm for calculation flow accumulation in a broken relief. Various algorithms could have complications with correct flow routing (representation of divergent or convergent character of the flow), or with keeping the flow paths uninterrupted. Relief with high curvature changes (alternating concave/convex shapes, high steepness changes) causes interrupting of flow lines in many algorithms used for hydrological computing. Second - set down limits of this theory (e.g. the size and character of a surveyed catchment). Third - verify this theory in reality. We tested this theory on sandstone landscape of National park Czech Switzerland. The main data source were high-resolution LIDAR (Light Detection and Ranging) DEM snapshots of surveyed area. This data comes from TU Dresden project called Genesis (Geoinformation Networks For The Cross- Border National Park Region Saxon- Bohemian Switzerland). In order to solve these issues GIS

  20. From Evidence Based Medicine to Medicine Based Evidence.

    PubMed

    Horwitz, Ralph I; Hayes-Conroy, Allison; Caricchio, Roberto; Singer, Burton H

    2017-11-01

    Evidence based medicine, using randomized controlled trials and meta-analyses as the major tools and sources of evidence about average results for heterogeneous groups of patients, developed as a reaction against poorly designed observational treatment research and physician reliance on personal experience with other patients as a guide to decision-making about a patient at hand. However, these tools do not answer the clinician's question: "Will a given therapeutic regimen help my patient at a given point in her/his clinical course?" We introduce fine-grained profiling of the patient at hand, accompanied by comparative evidence of responses from approximate matches to this patient on whom a contemplated treatment has/has not been administered. This represents medicine based evidence that is tuned to decision-making for the particular patient. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. East-West Cultural Differences in Context-Sensitivity are Evident in Early Childhood

    ERIC Educational Resources Information Center

    Imada, Toshie; Carlson, Stephanie M.; Itakura, Shoji

    2013-01-01

    Accumulating evidence suggests that North Americans tend to focus on central objects whereas East Asians tend to pay more attention to contextual information in a visual scene. Although it is generally believed that such culturally divergent attention tendencies develop through socialization, existing evidence largely depends on adult samples.…

  2. Tree diversity mitigates defoliation after a drought-induced tipping point.

    PubMed

    Sousa-Silva, Rita; Verheyen, Kris; Ponette, Quentin; Bay, Elodie; Sioen, Geert; Titeux, Hugues; Van de Peer, Thomas; Van Meerbeek, Koenraad; Muys, Bart

    2018-05-26

    Understanding the processes that underlie drought-related tree vitality loss is essential for anticipating future forest dynamics, and for developing management plans aiming at increasing the resilience of forests to climate change. Forest vitality has been continuously monitored in Europe since the acid rain alert in the 1980s, and the intensive monitoring plots of ICP Forests offer the opportunity to investigate the effects of air pollution and climate change on forest condition. By making use of over 100 long-term monitoring plots, where crown defoliation has been assessed extensively since 1990, we discovered a progressive shift from a negative to a positive effect of species richness on forest health. The observed tipping point in the balance of net interactions, from competition to facilitation, has never been reported from real ecosystems outside experimental conditions; and the strong temporal consistency of our observations with increasing drought stress emphasizes its climate change relevance. Furthermore, we show that higher species diversity has reduced the severity of defoliation in the long term. Our results confirm the greater resilience of diverse forests to future climate change-induced stress. More generally, they add to an accumulating body of evidence on the large potential of tree species mixtures to face manifold disturbances in a changing world. © 2018 John Wiley & Sons Ltd.

  3. cGMP accumulation causes photoreceptor degeneration in CNG channel deficiency: evidence of cGMP cytotoxicity independently of enhanced CNG channel function.

    PubMed

    Xu, Jianhua; Morris, Lynsie; Thapa, Arjun; Ma, Hongwei; Michalakis, Stylianos; Biel, Martin; Baehr, Wolfgang; Peshenko, Igor V; Dizhoor, Alexander M; Ding, Xi-Qin

    2013-09-11

    Photoreceptor cyclic nucleotide-gated (CNG) channels regulate Ca(2+) influx in rod and cone photoreceptors. cGMP, the native ligand of the photoreceptor CNG channels, has been associated with cytotoxicity when its levels rise above normal due to defects in photoreceptor phosphodiesterase (PDE6) or regulation of retinal guanylyl cyclase (retGC). We found a massive accumulation of cGMP in CNGA3-deficient retina and investigated whether cGMP accumulation plays a role in cone degeneration in CNG channel deficiency. The time course study showed that the retinal cGMP level in Cnga3(-/-);Nrl(-/-) mice with CNGA3 deficiency on a cone-dominant background was sharply increased at postnatal day 8 (P8), peaked around P10-P15, remained high through P30-P60, and returned to near control level at P90. This elevation pattern correlated with photoreceptor apoptotic death, which peaked around P15-P20. In Cnga3(-/-);Gucy2e(-/-) mice lacking retGC1, cone density and expression levels of cone-specific proteins were significantly increased compared with Cnga3(-/-), consistent with a role of cGMP accumulation as the major contributor to cone death caused by CNG channel deficiency. The activity and expression levels of cGMP-dependent protein kinase G (PKG) were significantly increased in Cnga3(-/-);Nrl(-/-) retina compared with Nrl(-/-), suggesting an involvement of PKG regulation in cell death. Our results indicate that cGMP accumulation in photoreceptors can itself exert cytotoxic effect in cones, independently of CNG channel activity and Ca(2+) influx.

  4. Deterrent effects of demerit points and license sanctions on drivers' traffic law violations using a proportional hazard model.

    PubMed

    Lee, Jaeyeong; Park, Byung-Jung; Lee, Chungwon

    2018-04-01

    Current traffic law enforcement places an emphasis on reducing accident risk from human factors such as drunk driving and speeding. Among the various strategies implemented, demerit points and license sanction systems have been widely used as punitive and educational measures. Limitations, however, exist in previous studies in terms of estimating the interaction effects of demerit points and license sanctions. To overcome such limitations, this work focused on identifying the interaction effects of demerit points and license sanctions on driver traffic violation behavior. The interaction deterrent effects were assessed by using a Cox's proportional hazard model to provide a more accurate and unbiased estimation. For this purpose, five years of driver conviction data was obtained from the Korea National Police Agency (KNPA). This data included personal characteristics, demerit point accumulation and license sanction status. The analysis showed that accumulated demerit points had specific deterrent effects. Additionally, license revocation showed consistent and significant deterrent effects, greater than those for suspension. Male drivers under their 30s holding a motorcycle license were identified as the most violation-prone driver group, suggesting that stricter testing for the acquisition of a motorcycle driver's license is needed. Copyright © 2018 Elsevier Ltd. All rights reserved.

  5. Environmental niche conservatism explains the accumulation of species richness in Mediterranean-hotspot plant genera.

    PubMed

    Skeels, Alexander; Cardillo, Marcel

    2017-03-01

    The causes of exceptionally high plant diversity in Mediterranean-climate biodiversity hotspots are not fully understood. We asked whether a mechanism similar to the tropical niche conservatism hypothesis could explain the diversity of four large genera (Protea, Moraea, Banksia, and Hakea) with distributions within and adjacent to the Greater Cape Floristic Region (South Africa) or the Southwest Floristic Region (Australia). Using phylogenetic and spatial data we estimated the environmental niche of each species, and reconstructed the mode and dynamics of niche evolution, and the geographic history, of each genus. For three genera, there were strong positive relationships between the diversity of clades within a region and their inferred length of occupation of that region. Within genera, there was evidence for strong evolutionary constraint on niche axes associated with climatic seasonality and aridity, with different niche optima for hotspot and nonhotspot clades. Evolutionary transitions away from hotspots were associated with increases in niche breadth and elevated rates of niche evolution. Our results point to a process of "hotspot niche conservatism" whereby the accumulation of plant diversity in Mediterranean-type ecosystems results from longer time for speciation, with dispersal away from hotspots limited by narrow and phylogenetically conserved environmental niches. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

  6. Difference in initial dental biofilm accumulation between night and day.

    PubMed

    Dige, Irene; Schlafer, Sebastian; Nyvad, Bente

    2012-12-01

    The study of initial microbial colonization on dental surfaces is a field of intensive research because of the aetiological role of biofilms in oral diseases. Most previous studies of de novo accumulation and composition of dental biofilms in vivo do not differentiate between biofilms formed during day and night. This study hypothesized that there is a diurnal variation in the rate of accumulation of bacteria on solid surfaces in the oral cavity. In situ biofilm from healthy individuals was collected for 12 h during day and night, respectively, subjected to fluorescent in situ hybridization and visualized using confocal laser scanning microscopy. Analysis of the biofilms using stereological methods and digital image analysis revealed a consistent statistically significant difference between both the total number of bacteria and the biovolume in the two 12-h groups (p = 0.012), with the highest accumulation of bacteria during daytime (a factor of 8.8 and 6.1 higher, respectively). Hybridization with probes specific for streptococci and Actinomyces naeslundii indicated a higher proportion of streptococci in biofilms grown during daytime as compared to night-time. No differences could be observed for A. naeslundii. The degree of microbial coverage and the bacterial composition varied considerably between different individuals. The data provide firm evidence that initial biofilm formation decreases during the night, which may reflect differences in the availability of salivary nutrients. This finding is of significant importance when studying population dynamics during experimental dental biofilm formation.

  7. Detection of the Cyanotoxins L-BMAA Uptake and Accumulation in Primary Neurons and Astrocytes.

    PubMed

    Tan, Vanessa X; Mazzocco, Claire; Varney, Bianca; Bodet, Dominique; Guillemin, Tristan A; Bessede, Alban; Guillemin, Gilles J

    2018-01-01

    We show for the first time that a newly developed polyclonal antibody (pAb) can specifically target the cyanotoxin β-methylamino-L-alanine (BMAA) and can be used to enable direct visualization of BMAA entry and accumulation in primary brain cells. We used this pAb to investigate the effect of acute and chronic accumulation, and toxicity of both BMAA and its natural isomer 2,4-diaminobutyric acid (DAB), separately or in combination, on primary cultures of rat neurons. We further present evidence that co-treatment with BMAA and DAB increased neuronal death, as measured by MAP2 fluorescence level, and appeared to reduce BMAA accumulation. DAB is likely to be acting synergistically with BMAA resulting in higher level of cellular toxicity. We also found that glial cells such as microglia and astrocytes are also able to directly uptake BMAA indicating that additional brain cell types are affected by BMAA-induced toxicity. Therefore, BMAA clearly acts at multiple cellular levels to possibly increase the risk of developing neurodegenerative diseases, including neuro- and gliotoxicity and synergetic exacerbation with other cyanotoxins.

  8. Radiation-induced effects on the mechanical properties of natural ZrSiO4: double cascade-overlap damage accumulation

    NASA Astrophysics Data System (ADS)

    Beirau, Tobias; Nix, William D.; Pöllmann, Herbert; Ewing, Rodney C.

    2018-05-01

    Several different models are known to describe the structure-dependent radiation-induced damage accumulation process in materials (e.g. Gibbons Proc IEEE 60:1062-1096, 1972; Weber Nuc Instr Met Phys Res B 166-167:98-106, 2000). In the literature, two different models of damage accumulation due to α-decay events in natural ZrSiO4 (zircon) have been described. The direct impact damage accumulation model is based on amorphization occurring directly within the collision cascade. However, the double cascade-overlap damage accumulation model predicts that amorphization will only occur due to the overlap of disordered domains within the cascade. By analyzing the dose-dependent evolution of mechanical properties (i.e., Poisson's ratios, compliance constants, elastic modulus, and hardness) as a measure of the increasing amorphization, we provide support for the double cascade-overlap damage accumulation model. We found no evidence to support the direct impact damage accumulation model. Additionally, the amount of radiation damage could be related to an anisotropic-to-isotropic transition of the Poisson's ratio for stress along and perpendicular to the four-fold c-axis and of the related compliance constants of natural U- and Th-bearing zircon. The isotropification occurs in the dose range between 3.1 × and 6.3 × 1018 α-decays/g.

  9. Radiation-induced effects on the mechanical properties of natural ZrSiO4: double cascade-overlap damage accumulation

    NASA Astrophysics Data System (ADS)

    Beirau, Tobias; Nix, William D.; Pöllmann, Herbert; Ewing, Rodney C.

    2017-11-01

    Several different models are known to describe the structure-dependent radiation-induced damage accumulation process in materials (e.g. Gibbons Proc IEEE 60:1062-1096, 1972; Weber Nuc Instr Met Phys Res B 166-167:98-106, 2000). In the literature, two different models of damage accumulation due to α-decay events in natural ZrSiO4 (zircon) have been described. The direct impact damage accumulation model is based on amorphization occurring directly within the collision cascade. However, the double cascade-overlap damage accumulation model predicts that amorphization will only occur due to the overlap of disordered domains within the cascade. By analyzing the dose-dependent evolution of mechanical properties (i.e., Poisson's ratios, compliance constants, elastic modulus, and hardness) as a measure of the increasing amorphization, we provide support for the double cascade-overlap damage accumulation model. We found no evidence to support the direct impact damage accumulation model. Additionally, the amount of radiation damage could be related to an anisotropic-to-isotropic transition of the Poisson's ratio for stress along and perpendicular to the four-fold c-axis and of the related compliance constants of natural U- and Th-bearing zircon. The isotropification occurs in the dose range between 3.1 × and 6.3 × 1018 α-decays/g.

  10. Sodium accumulation in Atriplex. Final report

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

    Norton, J.A.; Caldwell, M.M.; Richardson, S.G.

    1984-09-01

    This study was undertaken to determine the ecological significance and the significance to arid land reclamation of sodium accumulation and nonaccumulation in Atriplex. There was a continuum in the genetic tendency of Atriplex canescens to accumulate sodium, from populations which accumulated almost no sodium to populations which accumulated up to 7% in the leaves. There were also substantial differences in sodium uptake between populations of A. tridentata, A. falcata and A. gardneri, with some populations having less than 0.1% leaf sodium and other populations having up to 5 or 6%. In three experiments (a field study, a greenhouse pot studymore » and a hydroponics study) there were no significant differences in salinity tolerance between sodium accumulating and nonaccumulating A. canescens: both genotypes were highly salt tolerant. There was a significant buildup of sodium in the soil beneath sodium accumulating Atriplex plants, both in natural populations and on revegetated oil shale study plots. The sodium buildup was not sufficient to be detrimental to the growth or establishment of most herbaceous species, but with older Atriplex plants or with more saline soil, the buildup could potentially be detrimental. 14 references, 42 figures, 3 tables.« less

  11. Maximum likelihood decoding analysis of accumulate-repeat-accumulate codes

    NASA Technical Reports Server (NTRS)

    Abbasfar, A.; Divsalar, D.; Yao, K.

    2004-01-01

    In this paper, the performance of the repeat-accumulate codes with (ML) decoding are analyzed and compared to random codes by very tight bounds. Some simple codes are shown that perform very close to Shannon limit with maximum likelihood decoding.

  12. Fermion-induced quantum critical points.

    PubMed

    Li, Zi-Xiang; Jiang, Yi-Fan; Jian, Shao-Kai; Yao, Hong

    2017-08-22

    A unified theory of quantum critical points beyond the conventional Landau-Ginzburg-Wilson paradigm remains unknown. According to Landau cubic criterion, phase transitions should be first-order when cubic terms of order parameters are allowed by symmetry in the Landau-Ginzburg free energy. Here, from renormalization group analysis, we show that second-order quantum phase transitions can occur at such putatively first-order transitions in interacting two-dimensional Dirac semimetals. As such type of Landau-forbidden quantum critical points are induced by gapless fermions, we call them fermion-induced quantum critical points. We further introduce a microscopic model of SU(N) fermions on the honeycomb lattice featuring a transition between Dirac semimetals and Kekule valence bond solids. Remarkably, our large-scale sign-problem-free Majorana quantum Monte Carlo simulations show convincing evidences of a fermion-induced quantum critical points for N = 2, 3, 4, 5 and 6, consistent with the renormalization group analysis. We finally discuss possible experimental realizations of the fermion-induced quantum critical points in graphene and graphene-like materials.Quantum phase transitions are governed by Landau-Ginzburg theory and the exceptions are rare. Here, Li et al. propose a type of Landau-forbidden quantum critical points induced by gapless fermions in two-dimensional Dirac semimetals.

  13. Polyhydroxyalkanoate (PHA) accumulation potential and PHA-accumulating microbial communities in various activated sludge processes of municipal wastewater treatment plants.

    PubMed

    Sakai, K; Miyake, S; Iwama, K; Inoue, D; Soda, S; Ike, M

    2015-01-01

    To clarify the polyhydroxyalkanoate (PHA) accumulation potential and the PHA-accumulating microbial community structure in activated sludge in municipal wastewater treatment plants (WWTPs) and to identify their influential factors. Nine activated sludge samples were collected from municipal WWTPs employing various biological treatment processes. In acetate-fed 24-h batch experiments under aerobic and nitrogen- and phosphorus-limited conditions, polyhydroxybutyrate (PHB) content of activated sludge increased from 0-1·3 wt% to 7·9-24 wt%, with PHB yields of 0·22-0·50 C-mol 3-hydroxybutyrate (C-mol acetate)(-1). Microbial community analyses found that activated sludge samples that accumulated >20 wt% of PHB after 24-h PHA accumulation experiments had >5·0 × 10(8) copies g(-1)-mixed liquor-suspended solid of phaC genes. Results indicated that (i) activated sludge in municipal WWTPs can accumulate up to approx. 20 wt% of PHA without enrichment processes, (ii) PHA accumulation potential of activated sludge varied depending on the operational conditions (treatment processes) of WWTPs, and (iii) phaC gene number can provide a simple indication of PHA accumulation potential. This is the first study to compare the PHA accumulation potential and PHA-accumulating microbial communities in activated sludge of various treatment processes. Our findings may be useful for enhancing the resource recovery potential of wastewater treatment systems. © 2014 The Society for Applied Microbiology.

  14. Methylmercury production and accumulation in urban stormwater ponds and habitat wetlands.

    PubMed

    Strickman, R J; Mitchell, C P J

    2017-02-01

    Stormwater management ponds and created habitat wetlands effectively manage erosion, flooding, and pollutant loadings while providing biodiversity and aesthetic benefits, but these structures are also potential sources of methylmercury (MeHg), a bioaccumulative neurotoxin. While MeHg accumulation has been confirmed in habitat wetlands, the extent of MeHg production and accumulation in stormwater ponds is unknown. Additionally, the fine-scale spatial variation in MeHg in these wetlands has never been explored despite the possibility that cycles of wetting and drying, and the presence of aquatic plants may stimulate methylation at their margins. To address these knowledge gaps, we compared MeHg and inorganic mercury concentrations, the percent of total mercury present as MeHg (%MeHg), and potential mercury methylation rate constants (K meth ) in the sediments of terrestrial-aquatic transects through several stormwater and habitat wetlands. We present novel evidence confirming the in situ production of MeHg in both stormwater ponds and habitat wetlands, but observe no systematic differences across the terrestrial-aquatic gradient, suggesting that routine variations in water level do not alter MeHg production and accumulation. Stormwater ponds effectively trap mercury while converting relatively little to MeHg, as evidenced by lower MeHg concentrations, %-MeHg, and K meth values than habitat wetlands, but often greater inorganic Hg concentrations. The relationship of aquatic vegetation to MeHg accumulation is weak and ambiguous, suggesting plants are not strong drivers of MeHg biogeochemistry in these systems. Although the MeHg hazard associated with individual artificial wetlands is low, they may be important sources of MeHg at the landscape level. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Organochlorine pesticides accumulation and breast cancer: A hospital-based case-control study.

    PubMed

    He, Ting-Ting; Zuo, An-Jun; Wang, Ji-Gang; Zhao, Peng

    2017-05-01

    The aim of this study is to detect the accumulation status of organochlorine pesticides in breast cancer patients and to explore the relationship between organochlorine pesticides contamination and breast cancer development. We conducted a hospital-based case-control study in 56 patients with breast cancer and 46 patients with benign breast disease. We detected the accumulation level of several organochlorine pesticides products (β-hexachlorocyclohexane, γ-hexachlorocyclohexane, polychlorinated biphenyls-28, polychlorinated biphenyls-52, pentachlorothioanisole, and pp'-dichlorodiphenyldichloroethane) in breast adipose tissues of all 102 patients using gas chromatography. Thereafter, we examined the expression status of estrogen receptor, progesterone receptor, human epidermal growth factor receptor-2 (HER2), and Ki-67 in 56 breast cancer cases by immunohistochemistry. In addition, we analyzed the risk of breast cancer in those patients with organochlorine pesticides contamination using a logistic regression model. Our data showed that breast cancer patients suffered high accumulation levels of pp'-dichlorodiphenyldichloroethane and polychlorinated biphenyls-52. However, the concentrations of pp'-dichlorodiphenyldichloroethane and polychlorinated biphenyls-52 were not related to clinicopathologic parameters of breast cancer. Further logistic regression analysis showed polychlorinated biphenyls-52 and pp'-dichlorodiphenyldichloroethane were risk factors for breast cancer. Our results provide new evidence on etiology of breast cancer.

  16. A Cross-Cultural Study of Reference Point Adaptation: Evidence from China, Korea, and the US

    ERIC Educational Resources Information Center

    Arkes, Hal R.; Hirshleifer, David; Jiang, Danling; Lim, Sonya S.

    2010-01-01

    We examined reference point adaptation following gains or losses in security trading using participants from China, Korea, and the US. In both questionnaire studies and trading experiments with real money incentives, reference point adaptation was larger for Asians than for Americans. Subjects in all countries adapted their reference points more…

  17. [The forgotten capitulation of evidence-based medicine].

    PubMed

    Schoemaker, Casper G; Smulders, Yvo M

    2015-01-01

    In 1992, the Canadian physician Gordon Guyatt wrote an article that is generally regarded as the starting point of evidence-based medicine (EBM). He described the ideas behind the McMaster residency programme for 'evidence-based practitioners', founded by David Sackett. Eight years later, in 2000, Guyatt concluded that this programme was too ambitious. In a new publication he described most doctors as 'evidence-users'. This editorial marks the transition from an individual to a collective form of EBM, emphasizing the use of evidence-based guidelines. The starting point of this collective form of EBM is not the well-known 1992 paper, but the forgotten editorial in 2000, which was described by Guyatt's colleagues as the capitulation of EBM.

  18. Pointing Gestures as a Cognitive Tool in Young Children: Experimental Evidence

    ERIC Educational Resources Information Center

    Delgado, Begona; Gomez, Juan Carlos; Sarria, Encarnacion

    2011-01-01

    This article explores the possible cognitive function associated with pointing gestures from a Vygotskian perspective. In Study 1, 39 children who were 2-4 years of age were observed in a solitary condition while solving a mnemonic task with or without an explicit memory demand. A discriminant analysis showed that children used noncommunicative…

  19. A model for evidence accumulation in the lexical decision task.

    PubMed

    Wagenmakers, Eric-Jan; Steyvers, Mark; Raaijmakers, Jeroen G W; Shiffrin, Richard M; van Rijn, Hedderik; Zeelenberg, René

    2004-05-01

    We present a new model for lexical decision, REM-LD, that is based on REM theory (e.g., ). REM-LD uses a principled (i.e., Bayes' rule) decision process that simultaneously considers the diagnosticity of the evidence for the 'WORD' response and the 'NONWORD' response. The model calculates the odds ratio that the presented stimulus is a word or a nonword by averaging likelihood ratios for lexical entries from a small neighborhood of similar words. We report two experiments that used a signal-to-respond paradigm to obtain information about the time course of lexical processing. Experiment 1 verified the prediction of the model that the frequency of the word stimuli affects performance for nonword stimuli. Experiment 2 was done to study the effects of nonword lexicality, word frequency, and repetition priming and to demonstrate how REM-LD can account for the observed results. We discuss how REM-LD could be extended to account for effects of phonology such as the pseudohomophone effect, and how REM-LD can predict response times in the traditional 'respond-when-ready' paradigm.

  20. Effects of Point Mutations in the Major Capsid Protein of Beet Western Yellows Virus on Capsid Formation, Virus Accumulation, and Aphid Transmission

    PubMed Central

    Brault, V.; Bergdoll, M.; Mutterer, J.; Prasad, V.; Pfeffer, S.; Erdinger, M.; Richards, K. E.; Ziegler-Graff, V.

    2003-01-01

    Point mutations were introduced into the major capsid protein (P3) of cloned infectious cDNA of the polerovirus beet western yellows virus (BWYV) by manipulation of cloned infectious cDNA. Seven mutations targeted sites on the S domain predicted to lie on the capsid surface. An eighth mutation eliminated two arginine residues in the R domain, which is thought to extend into the capsid interior. The effects of the mutations on virus capsid formation, virus accumulation in protoplasts and plants, and aphid transmission were tested. All of the mutants replicated in protoplasts. The S-domain mutant W166R failed to protect viral RNA from RNase attack, suggesting that this particular mutation interfered with stable capsid formation. The R-domain mutant R7A/R8A protected ∼90% of the viral RNA strand from RNase, suggesting that lower positive-charge density in the mutant capsid interior interfered with stable packaging of the complete strand into virions. Neither of these mutants systemically infected plants. The six remaining mutants properly packaged viral RNA and could invade Nicotiana clevelandii systemically following agroinfection. Mutant Q121E/N122D was poorly transmitted by aphids, implicating one or both targeted residues in virus-vector interactions. Successful transmission of mutant D172N was accompanied either by reversion to the wild type or by appearance of a second-site mutation, N137D. This finding indicates that D172 is also important for transmission but that the D172N transmission defect can be compensated for by a “reverse” substitution at another site. The results have been used to evaluate possible structural models for the BWYV capsid. PMID:12584348

  1. Gypsum accumulation on carbonate stone

    USGS Publications Warehouse

    McGee, E.S.; Mossotti, V.G.

    1992-01-01

    The accumulation of gypsum on carbonate stone has been investigated through exposure of fresh samples of limestone and marble at monitored sites, through examination of alteration crusts from old buildings and through laboratory experiments. Several factors contribute to gypsum accumulation on carbonate stone. Marble or limestone that is sheltered from direct washing by rain in an urban environment with elevated pollution levels is likely to accumulate a gypsum crust. Crust development may be enhanced if the stone is porous or has an irregular surface area. Gypsum crusts are a surficial alteration feature; gypsum crystals form at the pore opening-air interface, where evaporation is greatest.

  2. Breast cancer risk accumulation starts early – Prevention must also

    PubMed Central

    Colditz, Graham A; Bohlke, Kari; Berkey, Catherine S.

    2014-01-01

    Purpose Nearly 1 in 4 breast cancers is diagnosed before the age of 50, and many early-stage premalignant lesions are present but not yet diagnosed. Therefore, we review evidence to support the strategy that breast cancer prevention efforts must begin early in life. Methods Literature review Results Exposures during childhood and adolescence affect a woman’s long-term risk of breast cancer, but have received far less research attention than exposures that occur later in life. Breast tissue undergoes rapid cellular proliferation between menarche and first full-term pregnancy, and risk accumulates rapidly until the terminal differentiation that accompanies first pregnancy. Evidence on childhood diet and growth in height, and adolescent alcohol intake, among other adolescent factors are related to breast cancer risk and risk of premalignant proliferative benign lesions. Conclusion Breast cancer prevention efforts will have the greatest effect when initiated at an early age and continued over a lifetime. Gaps in knowledge are identified and deserve increase attention to inform prevention. PMID:24820413

  3. Massive accumulation of luminal protease-deficient axonal lysosomes at Alzheimer’s disease amyloid plaques

    PubMed Central

    Gowrishankar, Swetha; Yuan, Peng; Wu, Yumei; Schrag, Matthew; Paradise, Summer; Grutzendler, Jaime; De Camilli, Pietro; Ferguson, Shawn M.

    2015-01-01

    Through a comprehensive analysis of organellar markers in mouse models of Alzheimer’s disease, we document a massive accumulation of lysosome-like organelles at amyloid plaques and establish that the majority of these organelles reside within swollen axons that contact the amyloid deposits. This close spatial relationship between axonal lysosome accumulation and extracellular amyloid aggregates was observed from the earliest stages of β-amyloid deposition. Notably, we discovered that lysosomes that accumulate in such axons are lacking in multiple soluble luminal proteases and thus are predicted to be unable to efficiently degrade proteinaceous cargos. Of relevance to Alzheimer’s disease, β-secretase (BACE1), the protein that initiates amyloidogenic processing of the amyloid precursor protein and which is a substrate for these proteases, builds up at these sites. Furthermore, through a comparison between the axonal lysosome accumulations at amyloid plaques and neuronal lysosomes of the wild-type brain, we identified a similar, naturally occurring population of lysosome-like organelles in neuronal processes that is also defined by its low luminal protease content. In conjunction with emerging evidence that the lysosomal maturation of endosomes and autophagosomes is coupled to their retrograde transport, our results suggest that extracellular β-amyloid deposits cause a local impairment in the retrograde axonal transport of lysosome precursors, leading to their accumulation and a blockade in their further maturation. This study both advances understanding of Alzheimer’s disease brain pathology and provides new insights into the subcellular organization of neuronal lysosomes that may have broader relevance to other neurodegenerative diseases with a lysosomal component to their pathology. PMID:26124111

  4. Jasmonate response decay and defense metabolite accumulation contributes to age-regulated dynamics of plant insect resistance

    PubMed Central

    Mao, Ying-Bo; Liu, Yao-Qian; Chen, Dian-Yang; Chen, Fang-Yan; Fang, Xin; Hong, Gao-Jie; Wang, Ling-Jian; Wang, Jia-Wei; Chen, Xiao-Ya

    2017-01-01

    Immunity deteriorates with age in animals but comparatively little is known about the temporal regulation of plant resistance to herbivores. The phytohormone jasmonate (JA) is a key regulator of plant insect defense. Here, we show that the JA response decays progressively in Arabidopsis. We show that this decay is regulated by the miR156-targeted SQUAMOSA PROMOTER BINDING PROTEIN-LIKE9 (SPL9) group of proteins, which can interact with JA ZIM-domain (JAZ) proteins, including JAZ3. As SPL9 levels gradually increase, JAZ3 accumulates and the JA response is attenuated. We provide evidence that this pathway contributes to insect resistance in young plants. Interestingly however, despite the decay in JA response, older plants are still comparatively more resistant to both the lepidopteran generalist Helicoverpa armigera and the specialist Plutella xylostella, along with increased accumulation of glucosinolates. We propose a model whereby constitutive accumulation of defense compounds plays a role in compensating for age-related JA-response attenuation during plant maturation. PMID:28067238

  5. Ontogenetic dynamics of mercury accumulation in Northwest Atlantic sea lamprey (Petromyzon marinus)

    USGS Publications Warehouse

    Drevnick, P.E.; Horgan, M.J.; Oris, J.T.; Kynard, B.E.

    2006-01-01

    We examined the ontogenetic dynamics of mercury accumulation in sea lamprey (Petromyzon marinus) from the Connecticut River, USA. Mercury concentrations in eggs (mean 84 ng??g-1 wet weight) were lowest of all life stages and correlated to concentrations in females. There was a higher rate of maternal transfer of mercury to eggs compared with teleosts. Ammocoetes had high mercury concentrations for their trophic level (e.g., mean of age-4 ammocoetes 492 ng??g-1 wet weight). A further investigation of four streams showed that ammocoetes reflected the level of contamination in their nursery streams. Concentrations of mercury decreased during metamorphosis from ammocoete to adult. Mercury concentrations in adults ranged from 83 to 942 ng??g-1 wet weight and, unlike teleosts, showed no relation to sex, length, or weight. We provide evidence from stable isotope analyses that this high variability is due to feeding ecology. There are fundamental differences in mercury accumulation between sea lamprey and teleosts. ?? 2006 NRC Canada.

  6. Rapid auxin-induced nitric oxide accumulation and subsequent tyrosine nitration of proteins during adventitious root formation in sunflower hypocotyls

    PubMed Central

    Yadav, Sunita; David, Anisha; Baluška, František; Bhatla, Satish C.

    2013-01-01

    Using NO specific probe (MNIP-Cu), rapid nitric oxide (NO) accumulation as a response to auxin (IAA) treatment has been observed in the protoplasts from the hypocotyls of sunflower seedlings (Helianthus annuus L.). Incubation of protoplasts in presence of NPA (auxin efflux blocker) and PTIO (NO scavenger) leads to significant reduction in NO accumulation, indicating that NO signals represent an early signaling event during auxin-induced response. A surge in NO production has also been demonstrated in whole hypocotyl explants showing adventitious root (AR) development. Evidence of tyrosine nitration of cytosolic proteins as a consequence of NO accumulation has been provided by western blot analysis and immunolocalization in the sections of AR producing hypocotyl segments. Most abundant anti-nitrotyrosine labeling is evident in proteins ranging from 25–80 kDa. Tyrosine nitration of a particular protein (25 kDa) is completely absent in presence of NPA (which suppresses AR formation). Similar lack of tyrosine nitration of this protein is also evident in other conditions which do not allow AR differentiation. Immunofluorescent localization experiments have revealed that non-inductive treatments (such as PTIO) for AR develpoment from hypocotyl segments coincide with symplastic and apoplastic localization of tyrosine nitrated proteins in the xylem elements, in contrast with negligible (and mainly apoplastic) nitration of proteins in the interfascicular cells and phloem elements. Application of NPA does not affect tyrosine nitration of proteins even in the presence of an external source of NO (SNP). Tyrosine nitrated proteins are abundant around the nuclei in the actively dividing cells of the root primordium. Thus, NO-modulated rapid response to IAA treatment through differential distribution of tyrosine nitrated proteins is evident as an inherent aspect of the AR development. PMID:23299324

  7. Accumulation, depuration dynamics and effects of dissolved hexavalent chromium in juvenile Japanese medaka (Oryzias latipes).

    PubMed

    Chen, Hongxing; Guo, Zhongbao; Zhou, Yu; Li, Dan; Mu, Lei; Klerks, Paul L; Luo, Yongju; Xie, Lingtian

    2018-02-01

    We previously demonstrated that chronic exposure to hexavalent chromium (Cr(VI)) causes a variety of adverse effects in the Japanese medaka (Oryzias latipes). The present study investigated the transition of acute to chronic effects by assessing the influences of Cr(VI) exposure concentration and exposure duration on Cr accumulation and their effects on fish growth and antioxidant physiology. Juvenile fish were exposed to 0.05, 0.5, 4 or 8mg/L Cr(VI) for 28 days. Endpoints were evaluated on days 3, 7, 14, 21 and 28. In addition, Cr depuration was examined for fish from two exposure groups (0.5 and 8mg/L). Chromium accumulation was rapid initially, then continued at a slower rate till the end of the exposure period without showing signs of reaching a steady state. Depuration patterns differed between the two exposure groups, but both reached 50% in 14 days. The rapid initial accumulation was accompanied by increased lipid peroxidation and elevated activities of antioxidants (e.g., GST, SOD and CAT). Activities of these enzymes had mostly returned to baseline levels by day 7, but there was no evidence of further cellular damage from ROS. Effects on fish length and weight continued to be evident over the 28-day exposure period. Our study suggest that the initial effects of Cr(VI) exposure may not be a good predictor of more-chronic effects in fish as a consequence of an efficient acclimation response by the antioxidant system that limits ROS-mediated toxicity. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Imagined Self-Motion Differs from Perceived Self-Motion: Evidence from a Novel Continuous Pointing Method

    PubMed Central

    Campos, Jennifer L.; Siegle, Joshua H.; Mohler, Betty J.; Bülthoff, Heinrich H.; Loomis, Jack M.

    2009-01-01

    Background The extent to which actual movements and imagined movements maintain a shared internal representation has been a matter of much scientific debate. Of the studies examining such questions, few have directly compared actual full-body movements to imagined movements through space. Here we used a novel continuous pointing method to a) provide a more detailed characterization of self-motion perception during actual walking and b) compare the pattern of responding during actual walking to that which occurs during imagined walking. Methodology/Principal Findings This continuous pointing method requires participants to view a target and continuously point towards it as they walk, or imagine walking past it along a straight, forward trajectory. By measuring changes in the pointing direction of the arm, we were able to determine participants' perceived/imagined location at each moment during the trajectory and, hence, perceived/imagined self-velocity during the entire movement. The specific pattern of pointing behaviour that was revealed during sighted walking was also observed during blind walking. Specifically, a peak in arm azimuth velocity was observed upon target passage and a strong correlation was observed between arm azimuth velocity and pointing elevation. Importantly, this characteristic pattern of pointing was not consistently observed during imagined self-motion. Conclusions/Significance Overall, the spatial updating processes that occur during actual self-motion were not evidenced during imagined movement. Because of the rich description of self-motion perception afforded by continuous pointing, this method is expected to have significant implications for several research areas, including those related to motor imagery and spatial cognition and to applied fields for which mental practice techniques are common (e.g. rehabilitation and athletics). PMID:19907655

  9. EBMPracticeNet: A Bilingual National Electronic Point-Of-Care Project for Retrieval of Evidence-Based Clinical Guideline Information and Decision Support

    PubMed Central

    2013-01-01

    Background In Belgium, the construction of a national electronic point-of-care information service, EBMPracticeNet, was initiated in 2011 to optimize quality of care by promoting evidence-based decision-making. The collaboration of the government, health care providers, evidence-based medicine (EBM) partners, and vendors of electronic health records (EHR) is unique to this project. All Belgian health care professionals get free access to an up-to-date database of validated Belgian and nearly 1000 international guidelines, incorporated in a portal that also provides EBM information from other sources than guidelines, including computerized clinical decision support that is integrated in the EHRs. Objective The objective of this paper was to describe the development strategy, the overall content, and the management of EBMPracticeNet which may be of relevance to other health organizations creating national or regional electronic point-of-care information services. Methods Several candidate providers of comprehensive guideline solutions were evaluated and one database was selected. Translation of the guidelines to Dutch and French was done with translation software, post-editing by translators and medical proofreading. A strategy is determined to adapt the guideline content to the Belgian context. Acceptance of the computerized clinical decision support tool has been tested and a randomized controlled trial is planned to evaluate the effect on process and patient outcomes. Results Currently, EBMPracticeNet is in "work in progress" state. Reference is made to the results of a pilot study and to further planned research including a randomized controlled trial. Conclusions The collaboration of government, health care providers, EBM partners, and vendors of EHRs is unique. The potential value of the project is great. The link between all the EHRs from different vendors and a national database held on a single platform that is controlled by all EBM organizations in Belgium

  10. Type II fish antifreeze protein accumulation in transgenic tobacco does not confer frost resistance.

    PubMed

    Kenward, K D; Brandle, J; McPherson, J; Davies, P L

    1999-04-01

    Type II fish antifreeze protein (AFP) is active in both freezing point depression and the inhibition of ice recrystallization. This extensively disulfide-bonded 14 kDa protein was targeted for accumulation in its pro- and mature forms in the cytosol and apoplast of transgenic tobacco plants. Type II AFP gene constructs under control of a duplicate cauliflower mosaic virus 35S promoter, both with and without a native plant transit peptide sequence, were introduced into tobacco by Agrobacterium tumefaciens-mediated transformation. AFP did not accumulate in the cytosol of transgenic plants, but active AFP was present as 2% the total protein present in the apoplast. Plant-produced AFP was the same size as mature Type II AFP isolated from fish, and was comparable to wild-type AFP in thermal hysteresis activity and its effect on ice crystal morphology. Field trials conducted in late summer on R1 generation transgenic plants showed similar AFP accumulation in plants under field conditions at levels suitable for large-scale production: but no difference in frost resistance was observed between transgenic and wild-type plants during the onset of early fall frosts.

  11. Correlation of neural activity with behavioral kinematics reveals distinct sensory encoding and evidence accumulation processes during active tactile sensing.

    PubMed

    Delis, Ioannis; Dmochowski, Jacek P; Sajda, Paul; Wang, Qi

    2018-07-15

    Many real-world decisions rely on active sensing, a dynamic process for directing our sensors (e.g. eyes or fingers) across a stimulus to maximize information gain. Though ecologically pervasive, limited work has focused on identifying neural correlates of the active sensing process. In tactile perception, we often make decisions about an object/surface by actively exploring its shape/texture. Here we investigate the neural correlates of active tactile decision-making by simultaneously measuring electroencephalography (EEG) and finger kinematics while subjects interrogated a haptic surface to make perceptual judgments. Since sensorimotor behavior underlies decision formation in active sensing tasks, we hypothesized that the neural correlates of decision-related processes would be detectable by relating active sensing to neural activity. Novel brain-behavior correlation analysis revealed that three distinct EEG components, localizing to right-lateralized occipital cortex (LOC), middle frontal gyrus (MFG), and supplementary motor area (SMA), respectively, were coupled with active sensing as their activity significantly correlated with finger kinematics. To probe the functional role of these components, we fit their single-trial-couplings to decision-making performance using a hierarchical-drift-diffusion-model (HDDM), revealing that the LOC modulated the encoding of the tactile stimulus whereas the MFG predicted the rate of information integration towards a choice. Interestingly, the MFG disappeared from components uncovered from control subjects performing active sensing but not required to make perceptual decisions. By uncovering the neural correlates of distinct stimulus encoding and evidence accumulation processes, this study delineated, for the first time, the functional role of cortical areas in active tactile decision-making. Copyright © 2018 Elsevier Inc. All rights reserved.

  12. Predictive Coding or Evidence Accumulation? False Inference and Neuronal Fluctuations

    PubMed Central

    Friston, Karl J.; Kleinschmidt, Andreas

    2010-01-01

    Perceptual decisions can be made when sensory input affords an inference about what generated that input. Here, we report findings from two independent perceptual experiments conducted during functional magnetic resonance imaging (fMRI) with a sparse event-related design. The first experiment, in the visual modality, involved forced-choice discrimination of coherence in random dot kinematograms that contained either subliminal or periliminal motion coherence. The second experiment, in the auditory domain, involved free response detection of (non-semantic) near-threshold acoustic stimuli. We analysed fluctuations in ongoing neural activity, as indexed by fMRI, and found that neuronal activity in sensory areas (extrastriate visual and early auditory cortex) biases perceptual decisions towards correct inference and not towards a specific percept. Hits (detection of near-threshold stimuli) were preceded by significantly higher activity than both misses of identical stimuli or false alarms, in which percepts arise in the absence of appropriate sensory input. In accord with predictive coding models and the free-energy principle, this observation suggests that cortical activity in sensory brain areas reflects the precision of prediction errors and not just the sensory evidence or prediction errors per se. PMID:20369004

  13. The virtues of evidence.

    PubMed

    Zarkovich, Erica; Upshur, R E G

    2002-01-01

    Evidence-based medicine has been defined as the conscientious and judicious use of current best evidence in making clinical decisions. This paper will attempt to explicate the terms "conscientious" and "judicious" within the evidence-based medicine definition. It will be argued that "conscientious" and "judicious" represent virtue terms derived from virtue ethics and virtue epistemology. The identification of explicit virtue components in the definition and therefore conception of evidence-based medicine presents an important starting point in the connection between virtue theories and medicine itself. In addition, a unification of virtue theories and evidence-based medicine will illustrate the need for future research in order to combine the fields of virtue-based approaches and clinical practice.

  14. Noise Reduction by Signal Accumulation

    ERIC Educational Resources Information Center

    Kraftmakher, Yaakov

    2006-01-01

    The aim of this paper is to show how the noise reduction by signal accumulation can be accomplished with a data acquisition system. This topic can be used for student projects. In many cases, the noise reduction is an unavoidable part of experimentation. Several techniques are known for this purpose, and among them the signal accumulation is the…

  15. Automated Point Cloud Correspondence Detection for Underwater Mapping Using AUVs

    NASA Technical Reports Server (NTRS)

    Hammond, Marcus; Clark, Ashley; Mahajan, Aditya; Sharma, Sumant; Rock, Stephen

    2015-01-01

    An algorithm for automating correspondence detection between point clouds composed of multibeam sonar data is presented. This allows accurate initialization for point cloud alignment techniques even in cases where accurate inertial navigation is not available, such as iceberg profiling or vehicles with low-grade inertial navigation systems. Techniques from computer vision literature are used to extract, label, and match keypoints between "pseudo-images" generated from these point clouds. Image matches are refined using RANSAC and information about the vehicle trajectory. The resulting correspondences can be used to initialize an iterative closest point (ICP) registration algorithm to estimate accumulated navigation error and aid in the creation of accurate, self-consistent maps. The results presented use multibeam sonar data obtained from multiple overlapping passes of an underwater canyon in Monterey Bay, California. Using strict matching criteria, the method detects 23 between-swath correspondence events in a set of 155 pseudo-images with zero false positives. Using less conservative matching criteria doubles the number of matches but introduces several false positive matches as well. Heuristics based on known vehicle trajectory information are used to eliminate these.

  16. The Feasibility of 3d Point Cloud Generation from Smartphones

    NASA Astrophysics Data System (ADS)

    Alsubaie, N.; El-Sheimy, N.

    2016-06-01

    This paper proposes a new technique for increasing the accuracy of direct geo-referenced image-based 3D point cloud generated from low-cost sensors in smartphones. The smartphone's motion sensors are used to directly acquire the Exterior Orientation Parameters (EOPs) of the captured images. These EOPs, along with the Interior Orientation Parameters (IOPs) of the camera/ phone, are used to reconstruct the image-based 3D point cloud. However, because smartphone motion sensors suffer from poor GPS accuracy, accumulated drift and high signal noise, inaccurate 3D mapping solutions often result. Therefore, horizontal and vertical linear features, visible in each image, are extracted and used as constraints in the bundle adjustment procedure. These constraints correct the relative position and orientation of the 3D mapping solution. Once the enhanced EOPs are estimated, the semi-global matching algorithm (SGM) is used to generate the image-based dense 3D point cloud. Statistical analysis and assessment are implemented herein, in order to demonstrate the feasibility of 3D point cloud generation from the consumer-grade sensors in smartphones.

  17. Influence of Vegetation on Sediment Accumulation in Restored Tidal Saltmarshes: Field Evidence from the Blackwater Estuary, Essex, UK

    NASA Astrophysics Data System (ADS)

    Price, D.; French, J.; Burningham, H.

    2013-12-01

    Tidal saltmarshes in the UK, and especially in the estuaries of southeast England, have been subject to degradation and erosion over the last few decades, primarily caused by sea-level rise and coastal squeeze due to fixed coastal defences. This is of great concern to a range of coastal stakeholders due to the corresponding loss of functions and services associated with these systems. The coastal defence role that saltmarshes play is well established, and the importance of saltmarsh ecosystems as habitats for birds, fish, and other species is evidenced in the fact that a large proportion of saltmarsh in the southeast England is designated for its scientific and conservation significance. Sediment accumulation is critical for the maintenance of marsh elevation within the tidal frame and for delivery of the aforementioned functions and services. Although many studies have examined accumulation processes, key questions have yet to be fully tested through intensive field observations. One such question relates to the role of vegetation in mediating the retention of newly introduced sediment, as recent research has called into doubt the traditional view of halophytes significantly enhancing rates of sedimentation through wave dissipation. This study presents early results from a project designed to advance our understanding of the processes controlling sediment accumulation. The research focuses on the UK's first large-scale experimental managed flood defence realignment at Tollesbury, Blackwater estuary, Essex. The seawall protecting 21ha of reclaimed agricultural land was artificially breached in 1995 and saltmarsh has progressively developed as tidal exchange has introduced fine sediment into the site. Results from a 12 month monitoring campaign involving hierarchical two-week sediment trap deployments indicates that the role of vegetation in marsh development is less clear cut that previously thought. Gross sedimentation rates were generally higher in non

  18. Light-induced morphological alteration in anthocyanin-accumulating vacuoles of maize cells

    PubMed Central

    Irani, Niloufer G; Grotewold, Erich

    2005-01-01

    Background Plant pigmentation is affected by a variety of factors. Light, an important plant developmental signal, influences the accumulation of anthocyanins primarily through the activation of the transcription factors that regulate the flavonoid biosynthetic pathway. In this study, we utilized maize Black Mexican Sweet (BMS) cells expressing the R and C1 regulators of anthocyanin biosynthesis from a light-insensitive promoter as a means to investigate the existence of additional levels of control of pigmentation by light. Results BMS cells expressing the R and C1 regulators from the CaMV 35S constitutive promoter accumulate anthocyanins when grown in complete darkness, suggesting that the transcription factors R and C1 are sufficient for the transcription of the genes corresponding to the structural enzymes of the pathway, with no requirement for additional light-induced regulators. Interestingly, light induces a "darkening" in the color of the purple anthocyanin pigmentation of transgenic BMS cells expressing R and C1. This change in the pigment hue is not associated with a variation in the levels or types of anthocyanins present, or with an alteration of the transcript levels of several flavonoid biosynthetic genes. However, cytological observations show that light drives unexpected changes in the morphology and distribution of the anthocyanins-containing vacuolar compartments. Conclusion By uncoupling the effect of light on anthocyanin accumulation, we have found light to induce the fusion of anthocyanin-containing vacuoles, the coalescence of anthocyanic vacuolar inclusion (AVI)-like structures contained, and the spread of anthocyanins from the inclusions into the vacuolar sap. Similar light-induced alterations in vacuolar morphology are also evident in the epidermal cells of maize floral whorls accumulating anthocyanins. Our findings suggest a novel mechanism for the action of light on the vacuolar storage of anthocyanin. PMID:15907203

  19. Functional Accumulation of Antenna Proteins in Chlorophyll b-Less Mutants of Chlamydomonas reinhardtii.

    PubMed

    Bujaldon, Sandrine; Kodama, Natsumi; Rappaport, Fabrice; Subramanyam, Rajagopal; de Vitry, Catherine; Takahashi, Yuichiro; Wollman, Francis-André

    2017-01-09

    The green alga Chlamydomonas reinhardtii contains several light-harvesting chlorophyll a/b complexes (LHC): four major LHCIIs, two minor LHCIIs, and nine LHCIs. We characterized three chlorophyll b-less mutants to assess the effect of chlorophyll b deficiency on the function, assembly, and stability of these chlorophyll a/b binding proteins. We identified point mutations in two mutants that inactivate the CAO gene responsible for chlorophyll a to chlorophyll b conversion. All LHCIIs accumulated to wild-type levels in a CAO mutant but their light-harvesting function for photosystem II was impaired. In contrast, most LHCIs accumulated to wild-type levels in the mutant and their light-harvesting capability for photosystem I remained unaltered. Unexpectedly, LHCI accumulation and the photosystem I functional antenna size increased in the mutant compared with in the wild type when grown in dim light. When the CAO mutation was placed in a yellow-in-the-dark background (yid-BF3), in which chlorophyll a synthesis remains limited in dim light, accumulation of the major LHCIIs and of most LHCIs was markedly reduced, indicating that sustained synthesis of chlorophyll a is required to preserve the proteolytic resistance of antenna proteins. Indeed, after crossing yid-BF3 with a mutant defective for the thylakoid FtsH protease activity, yid-BF3-ftsh1 restored wild-type levels of LHCI, which defines LHCI as a new substrate for the FtsH protease. Copyright © 2017 The Author. Published by Elsevier Inc. All rights reserved.

  20. Ice-binding proteins that accumulate on different ice crystal planes produce distinct thermal hysteresis dynamics

    PubMed Central

    Drori, Ran; Celik, Yeliz; Davies, Peter L.; Braslavsky, Ido

    2014-01-01

    Ice-binding proteins that aid the survival of freeze-avoiding, cold-adapted organisms by inhibiting the growth of endogenous ice crystals are called antifreeze proteins (AFPs). The binding of AFPs to ice causes a separation between the melting point and the freezing point of the ice crystal (thermal hysteresis, TH). TH produced by hyperactive AFPs is an order of magnitude higher than that produced by a typical fish AFP. The basis for this difference in activity remains unclear. Here, we have compared the time dependence of TH activity for both hyperactive and moderately active AFPs using a custom-made nanolitre osmometer and a novel microfluidics system. We found that the TH activities of hyperactive AFPs were time-dependent, and that the TH activity of a moderate AFP was almost insensitive to time. Fluorescence microscopy measurement revealed that despite their higher TH activity, hyperactive AFPs from two insects (moth and beetle) took far longer to accumulate on the ice surface than did a moderately active fish AFP. An ice-binding protein from a bacterium that functions as an ice adhesin rather than as an antifreeze had intermediate TH properties. Nevertheless, the accumulation of this ice adhesion protein and the two hyperactive AFPs on the basal plane of ice is distinct and extensive, but not detectable for moderately active AFPs. Basal ice plane binding is the distinguishing feature of antifreeze hyperactivity, which is not strictly needed in fish that require only approximately 1°C of TH. Here, we found a correlation between the accumulation kinetics of the hyperactive AFP at the basal plane and the time sensitivity of the measured TH. PMID:25008081

  1. Enhanced lipid accumulation of green microalga Scenedesmus sp. by metal ions and EDTA addition.

    PubMed

    Ren, Hong-Yu; Liu, Bing-Feng; Kong, Fanying; Zhao, Lei; Xie, Guo-Jun; Ren, Nan-Qi

    2014-10-01

    Effects of Fe(3+) (0-0.12 g/L), Mg(2+) (0-0.73 g/L) and Ca(2+) (0-0.98 g/L) on the biomass and lipid accumulation of heterotrophic microalgae were investigated in dark environment. The biomass and lipid production exhibited an increasing trend with increasing the concentrations of metal ions. In cultures with 1.2 × 10(-3) g/L Fe(3+), 7.3 × 10(-3) g/L Mg(2+) and 9.8 × 10(-4) g/L Ca(2+), the maximum biomass, total lipid content and lipid productivity reached 3.49 g/L, 47.4% and 275.7 mg/L/d, respectively. More importantly, EDTA addition (1.0 × 10(-3) g/L) could enhance the solubility of metal ions (iron and calcium) and increase their availability by microalgae, which evidently promote the lipid accumulation. Compared with the control, the total lipid content and lipid productivity increased 28.2% and 29.7%, respectively. These show that appropriate concentrations of metal ions and EDTA in the culture medium were beneficial to lipid accumulation of heterotrophic Scenedesmus sp. cells. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. When All Signs Point to You: Lies Told in the Face of Evidence

    PubMed Central

    Evans, Angela D.; Xu, Fen; Lee, Kang

    2012-01-01

    Young children’s ability to tell a strategic lie by making it consistent with the physical evidence of their transgression was investigated along with the sociocognitive correlates of such lie-telling behaviors. In Experiment 1, 247 Chinese children between 3 and 5 years of age (126 boys) were left alone in a room and asked not to lift a cup to see the contents. If children lifted up the cup, the contents would be spilled and evidence of their transgression would be left behind. Upon returning to the room, the experimenter asked children whether they peeked and how the contents of the cup ended up on the table. Experiment 1 revealed that young children are able to tell strategic lies to be consistent with the physical evidence by about 4 or 5 years of age, and this ability increases in sophistication with age. Experiment 2, which included 252 Chinese 4-year-olds (127 boys), identified 2 sociocognitive factors related to children’s ability to tell strategic lies. Specifically, both children’s theory-of-mind understanding and inhibitory control skills were significantly related to their ability to tell strategic lies in the face of physical evidence. The present investigation reveals that contrary to the prevailing views, even young children are able to tell strategic lies in some contexts. PMID:21244148

  3. The accumulation of genetic diversity within a canopy-stored seed bank.

    PubMed

    Ayre, David; O'Brien, Eleanor; Ottewell, Kym; Whelan, Rob

    2010-07-01

    Many plants regenerate after fire from a canopy-stored seed bank, in which seed are housed in fire resistant confructescences (cones) that remain on maternal plants. This strategy would be favoured if plants accumulate a sufficiently large and genetically diverse seed bank during interfire intervals. We use a 16-year demographic study and surveys of microsatellite variation to quantify and explain the rate of accumulation of genetic diversity within the canopy seed bank of the shrub Banksia spinulosa. Flowering and fruit set were highly variable. An initial sample in 1991 of 354 reproductively mature plants generated 426 cones over 16 years, of which only 55 cones from 40 maternal plants persisted until 2005. By genotyping seed from these 55 cones we demonstrated that genetic diversity accumulated rapidly within the seed bank. Resampling revealed that diversity was determined by the number, not the age, of cones. Cones were widely distributed among plants, outcrossing rates were high (mean t(m) = 1.00 +/- 0.04) and biparental inbreeding low. Adults displayed little evidence of isolation by distance and the genotypic diversity of seed cohorts was independent of the density of neighbouring potential sires. We therefore estimate that within at least 13 individual years the number of cones produced per year (14-63) would have contained 100% of the adult genetic diversity. We conclude that a highly outcrossed mating system and relatively widespread pollen dispersal ensure the rapid development of a genetically diverse and spatially and temporally homogeneous seed bank.

  4. Reduction of B-integral accumulation in lasers

    DOEpatents

    Meyerhofer, David D.; Konoplev, Oleg A.

    2000-01-01

    A pulsed laser is provided wherein the B-integral accumulated in the laser pulse is reduced using a semiconductor wafer. A laser pulse is generated by a laser pulse source. The laser pulse passes through a semiconductor wafer that has a negative nonlinear index of refraction. Thus, the laser pulse accumulates a negative B-integral. The laser pulse is then fed into a laser amplification medium, which has a positive nonlinear index of refraction. The laser pulse may make a plurality of passes through the laser amplification medium and accumulate a positive B-integral during a positive non-linear phase change. The semiconductor and laser pulse wavelength are chosen such that the negative B-integral accumulated in the semiconductor wafer substantially cancels the positive B-integral accumulated in the laser amplification medium. There may be additional accumulation of positive B-integral if the laser pulse passes through additional optical mediums such as a lens or glass plates. Thus, the effects of self-phase modulation in the laser pulse are substantially reduced.

  5. Influence of Fiber Type Composition and Capillary Density on Onset of Blood Lactate Accumulation,

    DTIC Science & Technology

    1981-03-25

    changes referred to as aerobic and anaerobic thresholds as suggested by e.g. Skinner and McLellan (32). To assess the "breaking point", which re- presents...in man. Acta Physiol Scand Suppl 443, 1976. 37 Wasserman K., Whipp B., Koyal S., Beaver t’. : Anaerobic threshold and respiratory gas exchange during...onset of a net accumulation of lactate in blood, has been proposed to represent a metabolic shift from aerobic to revalent anaerobic energy contribution

  6. How to get fat: nutritional mechanisms of seasonal fat accumulation in migratory songbirds

    NASA Astrophysics Data System (ADS)

    Bairlein, Franz

    2002-01-01

    Many migratory birds accumulate large amounts of lipids as the prime energy source for their long-distance flights. This fat accumulation is mostly under endogenous control, reflecting genetically programmed temporal shifts of the body mass set point. It is accompanied by an increase in daily food intake and food utilisation efficiency and by a seasonal shift in food selection. In particular, seasonal frugivory appears to play a key role in many migrants. Fruits have a high content of fatty acids indispensable for building up the specific depot lipids. In addition, plant secondary compounds seem to play some kind of supportive role, but the mechanisms are not yet known. The effect of being fat on the metabolic situation in migrant birds appears to be similar to the metabolic syndrome in obese humans. The fat migratory bird provides a model through which to study nutritional factors as well as the biochemical and endocrine regulation of food intake, body mass and obesity.

  7. Wetting and Layering for Solid-on-Solid I: Identification of the Wetting Point and Critical Behavior

    NASA Astrophysics Data System (ADS)

    Lacoin, Hubert

    2018-06-01

    We provide a complete description of the low temperature wetting transition for the two dimensional solid-on-solid model. More precisely, we study the integer-valued field {(φ(x))_{x\\in Z^2}} , associated associated with the energy functional V(φ)=β \\sum_{x ˜ y}|φ(x)-φ(y)|-\\sumx ( h{1}_{φ(x)=0}-∞{1}_{φ(x) < 0} ). Since the pioneering work Chalker [15], it is known that for every {β} , there exists {hw(β) > 0} delimiting a transition between a delocalized phase ({h < hw(β)} ) where the proportion of points at level zero vanishes, and a localized phase ({h > hw(β)} ) where this proportion is positive. We prove in the present paper that for {β} sufficiently large we have h_w(β)= log (e^{4β}/e^{4β-1} ). Furthermore, we provide a sharp asymptotic for the free energy at the vicinity of the critical line: We show that close to {h_w(β)} , the free energy is approximately piecewise affine and that the points of discontinuity for the derivative of the affine approximation forms a geometric sequence accumulating on the right of {h_w(β)} . This asymptotic behavior provides strong evidence for the conjectured existence of countably many "layering transitions" at the vicinity of the wetting line, corresponding to jumps for the typical height of the field.

  8. Vanillylacetone up-regulates anthocyanin accumulation and expression of anthocyanin biosynthetic genes by inducing endogenous abscisic acid in grapevine tissues.

    PubMed

    Enoki, Shinichi; Hattori, Tomoki; Ishiai, Shiho; Tanaka, Sayumi; Mikami, Masachika; Arita, Kayo; Nagasaka, Shu; Suzuki, Shunji

    2017-12-01

    We investigated the effect of vanillylacetone (VA) on anthocyanin accumulation with aim of improving grape berry coloration. Spraying Vitis vinifera cv. Muscat Bailey A berries with VA at veraison increased sugar/acid ratio, an indicator of maturation and total anthocyanin accumulation. To elucidate the molecular mechanism underlying the effect of VA on anthocyanin accumulation, in vitro VA treatment of a grapevine cell culture was carried out. Endogenous abscisic acid (ABA) content was higher in the VA-treated cell cultures than in control at 3h after treatment. Consistent with this, the relative expression levels of anthocyanin-synthesis-related genes, including DFR, LDOX, MybA1 and UFGT, in VA-treated cell cultures were much higher than those in control, and high total anthocyanin accumulation was noted in the VA-treated cell cultures as well. These results suggest that VA up-regulates the expression of genes leading to anthocyanin accumulation by inducing endogenous ABA. In addition, VA increased total anthocyanin content in a dose-dependent manner. Although VA treatment in combination with exogenous ABA did not exhibit any synergistic effect, treatment with VA alone showed an equivalent effect to that with exogenous ABA alone on total anthocyanin accumulation. These findings point to the possibility of using VA for improving grape berry coloration. Copyright © 2017 Elsevier GmbH. All rights reserved.

  9. Effect of collagen turnover on the accumulation of advanced glycation end products.

    PubMed

    Verzijl, N; DeGroot, J; Thorpe, S R; Bank, R A; Shaw, J N; Lyons, T J; Bijlsma, J W; Lafeber, F P; Baynes, J W; TeKoppele, J M

    2000-12-15

    Collagen molecules in articular cartilage have an exceptionally long lifetime, which makes them susceptible to the accumulation of advanced glycation end products (AGEs). In fact, in comparison to other collagen-rich tissues, articular cartilage contains relatively high amounts of the AGE pentosidine. To test the hypothesis that this higher AGE accumulation is primarily the result of the slow turnover of cartilage collagen, AGE levels in cartilage and skin collagen were compared with the degree of racemization of aspartic acid (% d-Asp, a measure of the residence time of a protein). AGE (N(epsilon)-(carboxymethyl)lysine, N(epsilon)-(carboxyethyl)lysine, and pentosidine) and % d-Asp concentrations increased linearly with age in both cartilage and skin collagen (p < 0.0001). The rate of increase in AGEs was greater in cartilage collagen than in skin collagen (p < 0.0001). % d-Asp was also higher in cartilage collagen than in skin collagen (p < 0.0001), indicating that cartilage collagen has a longer residence time in the tissue, and thus a slower turnover, than skin collagen. In both types of collagen, AGE concentrations increased linearly with % d-Asp (p < 0.0005). Interestingly, the slopes of the curves of AGEs versus % d-Asp, i.e. the rates of accumulation of AGEs corrected for turnover, were identical for cartilage and skin collagen. The present study thus provides the first experimental evidence that protein turnover is a major determinant in AGE accumulation in different collagen types. From the age-related increases in % d-Asp the half-life of cartilage collagen was calculated to be 117 years and that of skin collagen 15 years, thereby providing the first reasonable estimates of the half-lives of these collagens.

  10. Hydrogeological influences on petroleum accumulations in the Arabian Gulf

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

    Vizgirda, J.; Burke, L.

    1995-08-01

    The stratigraphic and topographic conditions in the Arabian Gulf are appropriate for the instigation and maintenance of an active hydrodynamic regime. The setting is that of a gentle basin surrounded by topographic highs. The central Arabian highlands to the west-southwest, the Tarus-Zagros mountains to the north, and the Oman mountains to the east rim the structural low occupied by the Gulf. Elevations in these areas reach maximum values of approximately 1000 meters. Paleozoic through Cenozoic strata stretch continuously across the basin, are relatively unfaulted, and outcrop in the topographic highs. Such a setting is propitious for a regional hydrodynamic systemmore » with meteoric recharge in the topographic highs and discharge in the middle of the Gulf. The prolific oil and gas accumulations of this region would be subject to influence by these hydrodynamic processes. The existence of such a hydrodynamic regime is documented by a variety of evidence, including potentiometric data, water salinity measurements, and observed tilts in oil-water contacts. Potentiometric data for several Tertiary and Cretaceous units on the Arabian platform, in the Gulf, and in Iraq show a pattern of consistently decreasing potential from topographic highs to lows. Water salinities show a consistent, but inverse, variation with the potentiometric data. Tilted oil-water contacts in Cretaceous and Jurassic reservoirs are observed in several fields of the Gulf region. The direction and magnitude of the observed tilts are consistent with the water potential and salinity data, and suggest that petroleum accumulations are being influenced by a regional hydrodynamic drive. Basin modelling is used to simulate petroleum generation and migration scenarios, and to integrate these histories with the structural evolution of the Gulf. The integrated modelling study illustrates the influence of hydrodynamic processes on the distribution of petroleum accumulations.« less

  11. Exercise decreases CLK2 in the liver of obese mice and prevents hepatic fat accumulation.

    PubMed

    Muñoz, Vitor R; Gaspar, Rafael C; Kuga, Gabriel K; Nakandakari, Susana C B R; Baptista, Igor L; Mekary, Rania A; da Silva, Adelino S R; de Moura, Leandro P; Ropelle, Eduardo R; Cintra, Dennys E; Pauli, José R

    2018-03-25

    The accumulation of fatty acids in the liver associated with obesity condition is also known as nonalcoholic fatty liver disease (NAFLD). The impaired fat oxidation in obesity condition leads to increased hepatic fat accumulation and increased metabolic syndrome risk. On the other hand, physical exercise has been demonstrated as a potent strategy in the prevention of NAFLD. Also, these beneficial effects of exercise occur through different mechanisms. Recently, the Cdc2-like kinase (CLK2) protein was associated with the suppression of fatty acid oxidation and hepatic ketogenesis. Thus, obese animals demonstrated elevated levels of hepatic CLK2 and decreased fat acid oxidation. Here, we explored the effects of chronic physical exercise in the hepatic metabolism of obese mice. Swiss mice were distributed in Lean, Obese (fed with high-fat diet during 16 weeks) and Trained Obese group (fed with high-fat diet during 16 weeks and exercised (at 60% exhaustion velocity during 1 h/5 days/week) during 8 weeks. In our results, the obese animals showed insulin resistance, increased hepatic CLK2 content and increased hepatic fat accumulation compared to the Lean group. Otherwise, the chronic physical exercise improved insulin resistance state, prevented the increased CLK2 in the liver and attenuated hepatic fat accumulation. In summary, these data reveal a new protein involved in the prevention of hepatic fat accumulation after chronic physical exercise. More studies can evidence the negative role of CLK2 in the control of liver metabolism, contributing to the improvement of insulin resistance, obesity, and type 2 diabetes. © 2018 Wiley Periodicals, Inc.

  12. Gender Recognition from Point-Light Walkers

    ERIC Educational Resources Information Center

    Pollick, Frank E.; Kay, Jim W.; Heim, Katrin; Stringer, Rebecca

    2005-01-01

    Point-light displays of human gait provide information sufficient to recognize the gender of a walker and are taken as evidence of the exquisite tuning of the visual system to biological motion. The authors revisit this topic with the goals of quantifying human efficiency at gender recognition. To achieve this, the authors first derive an ideal…

  13. Uptake and intra-inclusion accumulation of exogenous immunoglobulin by Chlamydia-infected cells

    PubMed Central

    Pollack, David V; Croteau, Nancy L; Stuart, Elizabeth S

    2008-01-01

    Background Obligate intracellular pathogens belonging to the Chlamydiaceae family possess a number of mechanisms by which to manipulate the host cell and surrounding environment. Such capabilities include the inhibition of apoptosis, down-regulation of major histocompatability complex (MHC) and CD1/d gene expression, and the acquisition of host-synthesized nutrients. It is also documented that a limited number of host-derived macromolecules such as β-catenin and sphingomyelin accumulate within the inclusion. Results This report provides evidence that immunoglobulin, inherently present in the extracellular environment in vivo and in vitro, enters infected cells and accumulates within the chlamydial inclusion. Using epi-fluorescent and confocal microscopy, this selective uptake of Ig is shown to occur among human leukocytes in vivo as well as cells cultured in vitro. These findings were confirmed by detection of IgG in the lysate of infected cells by western blot hybridization. Sequestered antibodies appear to be present during the entire course of the chlamydial developmental cycle and are distributed throughout this compartment. IgG pre-labeled with fluorescein, when added to the supernatant of infected cell cultures, was also imported and readily visualized. Accumulation of these molecules within the inclusion and the failure of bovine serum albumin or F(ab')2 fragments to accumulate in a similar manner suggests the process of entry is specific for intact IgG molecules and not a result of pinocytosis, diffusion, or any other mass endocytic event. Conclusion Sequestration of a host cell-derived protein within the chlamydial inclusion, although unexpected, is not an unprecedented occurrence. However, selective accumulation of an exogenous host protein, such as extracellular IgG, has not been previously reported in connection with chlamydial infections. The selectivity of this process may indicate that this uptake plays an important role in pathogen physiology or

  14. Functional Analysis of Arabidopsis Mutants Points to Novel Roles for Glutathione in Coupling H2O2 to Activation of Salicylic Acid Accumulation and Signaling

    PubMed Central

    Han, Yi; Chaouch, Sejir; Mhamdi, Amna; Queval, Guillaume; Zechmann, Bernd

    2013-01-01

    Abstract Aims: Through its interaction with H2O2, glutathione is a candidate for transmission of signals in plant responses to pathogens, but identification of signaling roles is complicated by its antioxidant function. Using a genetic approach based on a conditional catalase-deficient Arabidopsis mutant, cat2, this study aimed at establishing whether GSH plays an important functional role in the transmission of signals downstream of H2O2. Results: Introducing the cad2 or allelic mutations in the glutathione synthesis pathway into cat2 blocked H2O2-triggered GSH oxidation and accumulation. While no effects on NADP(H) or ascorbate were observed, and H2O2-induced decreases in growth were maintained, blocking GSH modulation antagonized salicylic acid (SA) accumulation and SA-dependent responses. Other novel double and triple mutants were produced and compared with cat2 cad2 at the levels of phenotype, expression of marker genes, nontargeted metabolite profiling, accumulation of SA, and bacterial resistance. Most of the effects of the cad2 mutation on H2O2-triggered responses were distinct from those produced by mutations for GLUTATHIONE REDUCTASE1 (GR1) or NONEXPRESSOR OF PATHOGENESIS-RELATED GENES 1 (NPR1), and were linked to compromised induction of ISOCHORISMATE SYNTHASE1 (ICS1) and ICS1-dependent SA accumulation. Innovation: A novel genetic approach was used in which GSH content or antioxidative capacity was independently modified in an H2O2 signaling background. Analysis of new double and triple mutants allowed us to infer previously undescribed regulatory roles for GSH. Conclusion: In parallel to its antioxidant role, GSH acts independently of NPR1 to allow increased intracellular H2O2 to activate SA signaling, a key defense response in plants. Antioxid. Redox Signal. 18, 2106–2121. PMID:23148658

  15. Spear-anvil point-contact spectroscopy in pulsed magnetic fields

    NASA Astrophysics Data System (ADS)

    Arnold, F.; Yager, B.; Kampert, E.; Putzke, C.; Nyéki, J.; Saunders, J.

    2013-11-01

    We describe a new design and experimental technique for point-contact spectroscopy in non-destructive pulsed magnetic fields up to 70 {T}. Point-contact spectroscopy uses a quasi-dc four-point measurement of the current and voltage across a spear-anvil point-contact. The contact resistance could be adjusted over three orders of magnitude by a built-in fine pitch threaded screw. The first measurements using this set-up were performed on both single-crystalline and exfoliated graphite samples in a 150 {ms}, pulse length 70 {T} coil at 4.2 {K} and reproduced the well known point-contact spectrum of graphite and showed evidence for a developing high field excitation above 35 T, the onset field of the charge-density wave instability in graphite.

  16. Molecular breeding of a novel orange-brown tomato fruit with enhanced beta-carotene and chlorophyll accumulation.

    PubMed

    Manoharan, Ranjith Kumar; Jung, Hee-Jeong; Hwang, Indeok; Jeong, Namhee; Kho, Kang Hee; Chung, Mi-Young; Nou, Ill-Sup

    2017-01-01

    Tomatoes provide a significant dietary source of the carotenoids, lycopene and β-carotene. During ripening, carotenoid accumulation determines the fruit colors while chlorophyll degradation. These traits have been, and continue to be, a significant focus for plant breeding efforts. Previous work has found strong evidence for a relationship between CYC-B gene expression and the orange color of fleshy fruit. Other work has identified a point mutation in SGR that impedes chlorophyll degradation and causes brown flesh color to be retained in some tomato varieties. We crossed two inbred lines, KNY2 (orange) and KNB1 (brown) and evaluated the relationship between these genes for their effect on fruit color. Phenotypes of F2 generation plants were analyzed and a novel 'orange-brown' fruit color was identified. We confirm two SNPs, one in CYC-B and another in SGR gene sequence, associated with segregation of 'orange-brown' fruit color in F2 generation. The carotenoid and chlorophyll content of a fleshy fruit was assessed across the different phenotypes and showed a strong correlation with expression pattern of carotenoid biosynthesis genes and SGR function. The orange-brown fruit has high β-carotene and chlorophyll. Our results provide valuable information for breeders to develop tomato fruit of a novel color using molecular markers.

  17. Evidence integration in model-based tree search

    PubMed Central

    Solway, Alec; Botvinick, Matthew M.

    2015-01-01

    Research on the dynamics of reward-based, goal-directed decision making has largely focused on simple choice, where participants decide among a set of unitary, mutually exclusive options. Recent work suggests that the deliberation process underlying simple choice can be understood in terms of evidence integration: Noisy evidence in favor of each option accrues over time, until the evidence in favor of one option is significantly greater than the rest. However, real-life decisions often involve not one, but several steps of action, requiring a consideration of cumulative rewards and a sensitivity to recursive decision structure. We present results from two experiments that leveraged techniques previously applied to simple choice to shed light on the deliberation process underlying multistep choice. We interpret the results from these experiments in terms of a new computational model, which extends the evidence accumulation perspective to multiple steps of action. PMID:26324932

  18. Evidence Value of Textile Fiber - Transfer and Persistence of Fibers.

    PubMed

    Siegel, J A

    1997-12-01

    Fibers comprise probably the most common form of trace evidence in forensic science today. They occur in perhaps one-quarter of all cases that involve trace evidence and a large majority of crime laboratories routinely characterize textile fibers. Although a great deal of research has been done on how to best characterize and compare fibers, relatively little time has been spent on determining the significance of fiber evidence. This article presents a summary of the studies of fiber transfer and persistence and determination of the significance of fiber evidence. This accumulated research and analysis will enable fiber examiners to better interpret evidence in cases where foreign fibers have been transferred during contact between victims and perpetrators of crimes. Copyright © 1997 Central Police University.

  19. The Accumulating Data to Optimally Predict Obesity Treatment (ADOPT) Core Measures Project: Rationale and Approach.

    PubMed

    MacLean, Paul S; Rothman, Alexander J; Nicastro, Holly L; Czajkowski, Susan M; Agurs-Collins, Tanya; Rice, Elise L; Courcoulas, Anita P; Ryan, Donna H; Bessesen, Daniel H; Loria, Catherine M

    2018-04-01

    Individual variability in response to multiple modalities of obesity treatment is well documented, yet our understanding of why some individuals respond while others do not is limited. The etiology of this variability is multifactorial; however, at present, we lack a comprehensive evidence base to identify which factors or combination of factors influence treatment response. This paper provides an overview and rationale of the Accumulating Data to Optimally Predict obesity Treatment (ADOPT) Core Measures Project, which aims to advance the understanding of individual variability in response to adult obesity treatment. This project provides an integrated model for how factors in the behavioral, biological, environmental, and psychosocial domains may influence obesity treatment responses and identify a core set of measures to be used consistently across adult weight-loss trials. This paper provides the foundation for four companion papers that describe the core measures in detail. The accumulation of data on factors across the four ADOPT domains can inform the design and delivery of effective, tailored obesity treatments. ADOPT provides a framework for how obesity researchers can collectively generate this evidence base and is a first step in an ongoing process that can be refined as the science advances. © 2018 The Obesity Society.

  20. Intravenous insertion site protection: moisture accumulation in intravenous site protectors.

    PubMed

    Lee, W E; Vallino, L M

    1996-01-01

    Stabilizing the intravenous catheter after insertion is a significant part of intravenous therapy. Dislodgments of the cannula from its optimal position in the vein can lead to complications such as phlebitis, thrombophlebitis, infiltration, and infection. Intravenous site protector shields are designed to protect the catheter from impact and tissue trauma at the insertion site. Nurses have requested ventilation in these shields to avoid moisture build up that may increase the risk of infections. To address this issue, experimental laboratory testing was performed to determine if moisture accumulation as evidenced by increased weight of the shield and visible evidence of condensation occurred. No moisture condensation problems with the ventilated intravenous site protectors were found.

  1. Process for structural geologic analysis of topography and point data

    DOEpatents

    Eliason, Jay R.; Eliason, Valerie L. C.

    1987-01-01

    A quantitative method of geologic structural analysis of digital terrain data is described for implementation on a computer. Assuming selected valley segments are controlled by the underlying geologic structure, topographic lows in the terrain data, defining valley bottoms, are detected, filtered and accumulated into a series line segments defining contiguous valleys. The line segments are then vectorized to produce vector segments, defining valley segments, which may be indicative of the underlying geologic structure. Coplanar analysis is performed on vector segment pairs to determine which vectors produce planes which represent underlying geologic structure. Point data such as fracture phenomena which can be related to fracture planes in 3-dimensional space can be analyzed to define common plane orientation and locations. The vectors, points, and planes are displayed in various formats for interpretation.

  2. The point system for driver license administration : a viable alternative for Virginia?.

    DOT National Transportation Integrated Search

    1972-01-01

    Traffic safety research was noted to have been unable to produce any empirical evidence that the introduction of a point system would affect, either negatively or positively, traffic accident statistics. In view of this absence of evidence, the simil...

  3. Selenium accumulation by plants

    PubMed Central

    White, Philip J.

    2016-01-01

    Background Selenium (Se) is an essential mineral element for animals and humans, which they acquire largely from plants. The Se concentration in edible plants is determined by the Se phytoavailability in soils. Selenium is not an essential element for plants, but excessive Se can be toxic. Thus, soil Se phytoavailability determines the ecology of plants. Most plants cannot grow on seleniferous soils. Most plants that grow on seleniferous soils accumulate <100 mg Se kg–1 dry matter and cannot tolerate greater tissue Se concentrations. However, some plant species have evolved tolerance to Se, and commonly accumulate tissue Se concentrations >100 mg Se kg–1 dry matter. These plants are considered to be Se accumulators. Some species can even accumulate Se concentrations of 1000–15 000 mg Se kg–1 dry matter and are called Se hyperaccumulators. Scope This article provides an overview of Se uptake, translocation and metabolism in plants and highlights the possible genetic basis of differences in these between and within plant species. The review focuses initially on adaptations allowing plants to tolerate large Se concentrations in their tissues and the evolutionary origin of species that hyperaccumulate Se. It then describes the variation in tissue Se concentrations between and within angiosperm species and identifies genes encoding enzymes limiting the rates of incorporation of Se into organic compounds and chromosomal loci that might enable the development of crops with greater Se concentrations in their edible portions. Finally, it discusses transgenic approaches enabling plants to tolerate greater Se concentrations in the rhizosphere and in their tissues. Conclusions The trait of Se hyperaccumulation has evolved several times in separate angiosperm clades. The ability to tolerate large tissue Se concentrations is primarily related to the ability to divert Se away from the accumulation of selenocysteine and selenomethionine, which might be incorporated

  4. Selenium accumulation by plants.

    PubMed

    White, Philip J

    2016-02-01

    Selenium (Se) is an essential mineral element for animals and humans, which they acquire largely from plants. The Se concentration in edible plants is determined by the Se phytoavailability in soils. Selenium is not an essential element for plants, but excessive Se can be toxic. Thus, soil Se phytoavailability determines the ecology of plants. Most plants cannot grow on seleniferous soils. Most plants that grow on seleniferous soils accumulate <100 mg Se kg(-1) dry matter and cannot tolerate greater tissue Se concentrations. However, some plant species have evolved tolerance to Se, and commonly accumulate tissue Se concentrations >100 mg Se kg(-1) dry matter. These plants are considered to be Se accumulators. Some species can even accumulate Se concentrations of 1000-15 000 mg Se kg(-1 )dry matter and are called Se hyperaccumulators. This article provides an overview of Se uptake, translocation and metabolism in plants and highlights the possible genetic basis of differences in these between and within plant species. The review focuses initially on adaptations allowing plants to tolerate large Se concentrations in their tissues and the evolutionary origin of species that hyperaccumulate Se. It then describes the variation in tissue Se concentrations between and within angiosperm species and identifies genes encoding enzymes limiting the rates of incorporation of Se into organic compounds and chromosomal loci that might enable the development of crops with greater Se concentrations in their edible portions. Finally, it discusses transgenic approaches enabling plants to tolerate greater Se concentrations in the rhizosphere and in their tissues. The trait of Se hyperaccumulation has evolved several times in separate angiosperm clades. The ability to tolerate large tissue Se concentrations is primarily related to the ability to divert Se away from the accumulation of selenocysteine and selenomethionine, which might be incorporated into non-functional proteins

  5. Enhanced Insight into the Autoimmune Component of Glaucoma: IgG Autoantibody Accumulation and Pro-Inflammatory Conditions in Human Glaucomatous Retina

    PubMed Central

    Gramlich, Oliver W.; Beck, Sabine; von Thun und Hohenstein-Blaul, Nadine; Boehm, Nils; Ziegler, Anika; Vetter, Jan M.; Pfeiffer, Norbert; Grus, Franz H.

    2013-01-01

    Background There is accumulating evidence that autoimmune components, such as autoantibodies and autoantibody depositions, play a role in the pathogenesis of neurodegenerative diseases like Alzheimeŕs disease or Multiple Sclerosis. Due to alterations of autoantibody patterns in sera and aqueous humor, an autoimmune component is also assumed in the pathogenesis of glaucoma, a common reason for irreversible blindness worldwide. So far there has been no convincing evidence that autoantibodies are accumulated in the retina of glaucoma patients and that the local immune homeostasis might be affected. Methods and Results Six human glaucomatous donor eyes and nine samples from donors with no recorded ocular disease were included. Antibody microarrays were used to examine the patterns of pro-inflammatory proteins and complement proteins. Analysis of TNF-α and interleukin levels revealed a slight up-regulation exclusively in the glaucomatous group, while complement protein levels were not altered. IgG autoantibody accumulations and/or cellular components were determined by immunohistology (n = 4 per group). A significantly reduced number of retinal ganglion cells was found in the glaucomatous group (healthy: 104±7 nuclei/mm, glaucoma: 67±9 nuclei/mm; p = 0.0007). Cell loss was accompanied by strong retinal IgG autoantibody accumulations, which were at least twice as high as in healthy subjects (healthy: 5.0±0.5 IgG deposits/100 cells, glaucoma: 9.4±1.9 IgG deposits/100 cells; p = 0.004). CD27+ cells and CD27+/IgG+ plasma cells were observed in all glaucomatous subjects, but not in controls. Conclusion This work provides serious evidence for the occurrence of IgG antibody deposition and plasma cells in human glaucomatous retina. Moreover, the results suggest that these IgG deposits occurred in a pro-inflammatory environment which seems to be maintained locally by immune-competent cells like microglia. Thereby, glaucoma features an immunological involvement

  6. Triana Safehold: A New Gyroless, Sun-Pointing Attitude Controller

    NASA Technical Reports Server (NTRS)

    Chen, J.; Morgenstern, Wendy; Garrick, Joseph

    2001-01-01

    Triana is a single-string spacecraft to be placed in a halo orbit about the sun-earth Ll Lagrangian point. The Attitude Control Subsystem (ACS) hardware includes four reaction wheels, ten thrusters, six coarse sun sensors, a star tracker, and a three-axis Inertial Measuring Unit (IMU). The ACS Safehold design features a gyroless sun-pointing control scheme using only sun sensors and wheels. With this minimum hardware approach, Safehold increases mission reliability in the event of a gyroscope anomaly. In place of the gyroscope rate measurements, Triana Safehold uses wheel tachometers to help provide a scaled estimation of the spacecraft body rate about the sun vector. Since Triana nominally performs momentum management every three months, its accumulated system momentum can reach a significant fraction of the wheel capacity. It is therefore a requirement for Safehold to maintain a sun-pointing attitude even when the spacecraft system momentum is reasonably large. The tachometer sun-line rate estimation enables the controller to bring the spacecraft close to its desired sun-pointing attitude even with reasonably high system momentum and wheel drags. This paper presents the design rationale behind this gyroless controller, stability analysis, and some time-domain simulation results showing performances with various initial conditions. Finally, suggestions for future improvements are briefly discussed.

  7. Plastids and Carotenoid Accumulation.

    PubMed

    Li, Li; Yuan, Hui; Zeng, Yunliu; Xu, Qiang

    Plastids are ubiquitously present in plants and are the organelles for carotenoid biosynthesis and storage. Based on their morphology and function, plastids are classified into various types, i.e. proplastids, etioplasts, chloroplasts, amyloplasts, and chromoplasts. All plastids, except proplastids, can synthesize carotenoids. However, plastid types have a profound effect on carotenoid accumulation and stability. In this chapter, we discuss carotenoid biosynthesis and regulation in various plastids with a focus on carotenoids in chromoplasts. Plastid transition related to carotenoid biosynthesis and the different capacity of various plastids to sequester carotenoids and the associated effect on carotenoid stability are described in light of carotenoid accumulation in plants.

  8. Myofascial trigger points: spontaneous electrical activity and its consequences for pain induction and propagation

    PubMed Central

    2011-01-01

    Active myofascial trigger points are one of the major peripheral pain generators for regional and generalized musculoskeletal pain conditions. Myofascial trigger points are also the targets for acupuncture and/or dry needling therapies. Recent evidence in the understanding of the pathophysiology of myofascial trigger points supports The Integrated Hypothesis for the trigger point formation; however unanswered questions remain. Current evidence shows that spontaneous electrical activity at myofascial trigger point originates from the extrafusal motor endplate. The spontaneous electrical activity represents focal muscle fiber contraction and/or muscle cramp potentials depending on trigger point sensitivity. Local pain and tenderness at myofascial trigger points are largely due to nociceptor sensitization with a lesser contribution from non-nociceptor sensitization. Nociceptor and non-nociceptor sensitization at myofascial trigger points may be part of the process of muscle ischemia associated with sustained focal muscle contraction and/or muscle cramps. Referred pain is dependent on the sensitivity of myofascial trigger points. Active myofascial trigger points may play an important role in the transition from localized pain to generalized pain conditions via the enhanced central sensitization, decreased descending inhibition and dysfunctional motor control strategy. PMID:21439050

  9. Accumulation of Polychlorinated Biphenyls in Adipocytes: Selective Targeting to Lipid Droplets and Role of Caveolin-1

    PubMed Central

    Bourez, Sophie; Le Lay, Soazig; Van den Daelen, Carine; Louis, Caroline; Larondelle, Yvan; Thomé, Jean-Pierre; Schneider, Yves-Jacques; Dugail, Isabelle; Debier, Cathy

    2012-01-01

    Background Polychlorinated biphenyls (PCBs) are persistent environmental pollutants that preferentially accumulate in lipid-rich tissues of contaminated organisms. Although the adipose tissue constitutes a major intern reservoir of PCBs and recent epidemiological studies associate PCBs to the development of obesity and its related disorders, little is known about the mechanisms involved in their uptake by the adipose tissue and their intracellular localization in fat cells. Methodology/Principal Findings We have examined the intracellular distribution of PCBs in mouse cultured adipocytes and tested the potential involvement of caveolin-1, an abundant adipocyte membrane protein, in the uptake of these compounds by fat cells. We show that 2,4,4′-trichlorobiphenyl (PCB-28), 2,3′,4,4′,5-pentachlorobiphenyl (PCB-118) and 2,2′,4,4′,5,5′-hexachlorobiphenyl (PCB-153) congeners rapidly and extensively accumulate in 3T3-L1 or mouse embryonic fibroblast (MEF) derived cultured adipocytes. The dynamics of accumulation differed between the 3 congeners tested. By subcellular fractionation of primary adipocytes, we demonstrate that these pollutants were almost exclusively recovered within the lipid droplet fraction and practically not associated to cell membranes. The absence of caveolin-1 expression in primary adipocytes from cav-1 deficient mice did not modify lipid droplet selective targeting of PCBs. In cav-1 KO MEF differentiated adipocytes, PCB accumulation was decreased, which correlated with reduced cell triglyceride content. Conversely, adenoviral mediated cav-1 overexpressing in 3T3-L1 cells, which had no impact on total cell lipid content, did not change PCB accumulation. Conclusion/Significance Our data indicate that caveolin-1 per se is not required for selective PCB accumulation, but rather point out a primary dependence on adipocyte triglyceride content. If the crucial role of lipid droplets in energy homeostasis is considered, the almost exclusive

  10. Determinants of reinforcer accumulation during an operant task.

    PubMed

    McFarland, J M; Lattal, K A

    2001-11-01

    Responses by rats on an earn lever made available food pellets that were delivered to a food cup by responses on a second, collect, lever. The rats could either collect and immediately consume or accumulate (defined as the percentage of multiple earn responses and as the number of pellets earned before a collect response) earned pellets. In Experiment 1, accumulation varied as a function of variations in the earn or collect response requirements and whether the earn and collect levers were proximal (31 cm) or distal (248 cm) to one another. Some accumulation occurred under all but one of the conditions, but generally was higher when the earn and collect levers were distal to one another, particularly when the earn response requirement was fixed-ratio (FR) 1. In Experiment 2, the contributions of responses and time to accumulation were assessed by comparing an FR 20 earn response requirement to a condition in which only a single earn response was required at the end of a time interval nominally yoked to the FR interval. When 248 cm separated the earn and collect levers, accumulation was always greater in the FR condition, and it was not systematically related to reinforcement rate. In Experiment 3, increasing the earn response requirement with a progressive-ratio schedule that reset only with a collect response increased the likelihood of accumulation when the collect and earn levers were 248 cm apart, even though such accumulation increased the next earn response requirement. Reinforcer accumulation is an understudied dimension of operant behavior that relates to the analysis of such phenomena as hoarding and self-control, in that they too involve accumulating versus immediately collecting or consuming reinforcers.

  11. Flavonols Accumulate Asymmetrically and Affect Auxin Transport in Arabidopsis1[C][W][OA

    PubMed Central

    Kuhn, Benjamin M.; Geisler, Markus; Bigler, Laurent; Ringli, Christoph

    2011-01-01

    Flavonoids represent a class of secondary metabolites with diverse functions in plants including ultraviolet protection, pathogen defense, and interspecies communication. They are also known as modulators of signaling processes in plant and animal systems and therefore are considered to have beneficial effects as nutraceuticals. The rol1-2 (for repressor of lrx1) mutation of Arabidopsis (Arabidopsis thaliana) induces aberrant accumulation of flavonols and a cell-growth phenotype in the shoot. The hyponastic cotyledons, aberrant shape of pavement cells, and deformed trichomes in rol1-2 mutants are suppressed by blocking flavonoid biosynthesis, suggesting that the altered flavonol accumulation in these plants induces the shoot phenotype. Indeed, the identification of several transparent testa, myb, and fls1 (for flavonol synthase1) alleles in a rol1-2 suppressor screen provides genetic evidence that flavonols interfere with shoot development in rol1-2 seedlings. The increased accumulation of auxin in rol1-2 seedlings appears to be caused by a flavonol-induced modification of auxin transport. Quantification of auxin export from mesophyll protoplasts revealed that naphthalene-1-acetic acid but not indole-3-acetic acid transport is affected by the rol1-2 mutation. Inhibition of flavonol biosynthesis in rol1-2 fls1-3 restores naphthalene-1-acetic acid transport to wild-type levels, indicating a very specific mode of action of flavonols on the auxin transport machinery. PMID:21502189

  12. Nanoparticle accumulation and transcytosis in brain endothelial cell layers

    NASA Astrophysics Data System (ADS)

    Ye, Dong; Raghnaill, Michelle Nic; Bramini, Mattia; Mahon, Eugene; Åberg, Christoffer; Salvati, Anna; Dawson, Kenneth A.

    2013-10-01

    The blood-brain barrier (BBB) is a selective barrier, which controls and limits access to the central nervous system (CNS). The selectivity of the BBB relies on specialized characteristics of the endothelial cells that line the microvasculature, including the expression of intercellular tight junctions, which limit paracellular permeability. Several reports suggest that nanoparticles have a unique capacity to cross the BBB. However, direct evidence of nanoparticle transcytosis is difficult to obtain, and we found that typical transport studies present several limitations when applied to nanoparticles. In order to investigate the capacity of nanoparticles to access and transport across the BBB, several different nanomaterials, including silica, titania and albumin- or transferrin-conjugated gold nanoparticles of different sizes, were exposed to a human in vitro BBB model of endothelial hCMEC/D3 cells. Extensive transmission electron microscopy imaging was applied in order to describe nanoparticle endocytosis and typical intracellular localisation, as well as to look for evidence of eventual transcytosis. Our results show that all of the nanoparticles were internalised, to different extents, by the BBB model and accumulated along the endo-lysosomal pathway. Rare events suggestive of nanoparticle transcytosis were also observed for several of the tested materials.The blood-brain barrier (BBB) is a selective barrier, which controls and limits access to the central nervous system (CNS). The selectivity of the BBB relies on specialized characteristics of the endothelial cells that line the microvasculature, including the expression of intercellular tight junctions, which limit paracellular permeability. Several reports suggest that nanoparticles have a unique capacity to cross the BBB. However, direct evidence of nanoparticle transcytosis is difficult to obtain, and we found that typical transport studies present several limitations when applied to nanoparticles. In

  13. Dynamically accumulated dose and 4D accumulated dose for moving tumors

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

    Li Heng; Li Yupeng; Zhang Xiaodong

    2012-12-15

    Purpose: The purpose of this work was to investigate the relationship between dynamically accumulated dose (dynamic dose) and 4D accumulated dose (4D dose) for irradiation of moving tumors, and to quantify the dose uncertainty induced by tumor motion. Methods: The authors established that regardless of treatment modality and delivery properties, the dynamic dose will converge to the 4D dose, instead of the 3D static dose, after multiple deliveries. The bounds of dynamic dose, or the maximum estimation error using 4D or static dose, were established for the 4D and static doses, respectively. Numerical simulations were performed (1) to prove themore » principle that for each phase, after multiple deliveries, the average number of deliveries for any given time converges to the total number of fractions (K) over the number of phases (N); (2) to investigate the dose difference between the 4D and dynamic doses as a function of the number of deliveries for deliveries of a 'pulsed beam'; and (3) to investigate the dose difference between 4D dose and dynamic doses as a function of delivery time for deliveries of a 'continuous beam.' A Poisson model was developed to estimate the mean dose error as a function of number of deliveries or delivered time for both pulsed beam and continuous beam. Results: The numerical simulations confirmed that the number of deliveries for each phase converges to K/N, assuming a random starting phase. Simulations for the pulsed beam and continuous beam also suggested that the dose error is a strong function of the number of deliveries and/or total deliver time and could be a function of the breathing cycle, depending on the mode of delivery. The Poisson model agrees well with the simulation. Conclusions: Dynamically accumulated dose will converge to the 4D accumulated dose after multiple deliveries, regardless of treatment modality. Bounds of the dynamic dose could be determined using quantities derived from 4D doses, and the mean dose

  14. Quantitation of cell-associated carbon nanotubes: selective binding and accumulation of carboxylated carbon nanotubes by macrophages.

    PubMed

    Wang, Ruhung; Lee, Michael; Kinghorn, Karina; Hughes, Tyler; Chuckaree, Ishwar; Lohray, Rishabh; Chow, Erik; Pantano, Paul; Draper, Rockford

    2018-05-26

    To understand the influence of carboxylation on the interaction of carbon nanotubes with cells, the amount of pristine multi-walled carbon nanotubes (P-MWNTs) or carboxylated multi-walled carbon nanotubes (C-MWNTs) coated with Pluronic ® F-108 that were accumulated by macrophages was measured by quantifying CNTs extracted from cells. Mouse RAW 264.7 macrophages and differentiated human THP-1 (dTHP-1) macrophages accumulated 80-100 times more C-MWNTs than P-MWNTs during a 24-h exposure at 37 °C. The accumulation of C-MWNTs by RAW 264.7 cells was not lethal; however, phagocytosis was impaired as subsequent uptake of polystyrene beads was reduced after a 20-h exposure to C-MWNTs. The selective accumulation of C-MWNTs suggested that there might be receptors on macrophages that bind C-MWNTs. The binding of C-MWNTs to macrophages was measured as a function of concentration at 4 °C in the absence of serum to minimize the potential interference by serum proteins or temperature-dependent uptake processes. The result was that the cells bound 8.7 times more C-MWNTs than P-MWNTs, consistent with the selective accumulation of C-MWNTs at 37 °C. In addition, serum strongly antagonized the binding of C-MWTS to macrophages, suggesting that serum contained inhibitors of binding. Moreover, inhibitors of class A scavenger receptor (SR-As) reduced the binding of C-MWNTs by about 50%, suggesting that SR-As contribute to the binding and endocytosis of C-MWNTs in macrophages but that other receptors may also be involved. Altogether, the evidence supports the hypothesis that macrophages contain binding sites selective for C-MWNTs that facilitate the high accumulation of C-MWNTs compared to P-MWNTs.

  15. Plastic Accumulation in the Mediterranean Sea

    PubMed Central

    Cózar, Andrés; Sanz-Martín, Marina; Martí, Elisa; González-Gordillo, J. Ignacio; Ubeda, Bárbara; Gálvez, José Á.; Irigoien, Xabier; Duarte, Carlos M.

    2015-01-01

    Concentrations of floating plastic were measured throughout the Mediterranean Sea to assess whether this basin can be regarded as a great accumulation region of plastic debris. We found that the average density of plastic (1 item per 4 m2), as well as its frequency of occurrence (100% of the sites sampled), are comparable to the accumulation zones described for the five subtropical ocean gyres. Plastic debris in the Mediterranean surface waters was dominated by millimeter-sized fragments, but showed a higher proportion of large plastic objects than that present in oceanic gyres, reflecting the closer connection with pollution sources. The accumulation of floating plastic in the Mediterranean Sea (between 1,000 and 3,000 tons) is likely related to the high human pressure together with the hydrodynamics of this semi-enclosed basin, with outflow mainly occurring through a deep water layer. Given the biological richness and concentration of economic activities in the Mediterranean Sea, the affects of plastic pollution on marine and human life are expected to be particularly frequent in this plastic accumulation region. PMID:25831129

  16. Plastic accumulation in the Mediterranean sea.

    PubMed

    Cózar, Andrés; Sanz-Martín, Marina; Martí, Elisa; González-Gordillo, J Ignacio; Ubeda, Bárbara; Gálvez, José Á; Irigoien, Xabier; Duarte, Carlos M

    2015-01-01

    Concentrations of floating plastic were measured throughout the Mediterranean Sea to assess whether this basin can be regarded as a great accumulation region of plastic debris. We found that the average density of plastic (1 item per 4 m2), as well as its frequency of occurrence (100% of the sites sampled), are comparable to the accumulation zones described for the five subtropical ocean gyres. Plastic debris in the Mediterranean surface waters was dominated by millimeter-sized fragments, but showed a higher proportion of large plastic objects than that present in oceanic gyres, reflecting the closer connection with pollution sources. The accumulation of floating plastic in the Mediterranean Sea (between 1,000 and 3,000 tons) is likely related to the high human pressure together with the hydrodynamics of this semi-enclosed basin, with outflow mainly occurring through a deep water layer. Given the biological richness and concentration of economic activities in the Mediterranean Sea, the affects of plastic pollution on marine and human life are expected to be particularly frequent in this plastic accumulation region.

  17. Evidence of anthropogenic tipping points in fluvial dynamics in Europe

    NASA Astrophysics Data System (ADS)

    Notebaert, Bastiaan; Broothaerts, Nils; Verstraeten, Gert

    2018-05-01

    In this study the occurrence of thresholds in fluvial style changes during the Holocene are discussed for three different catchments: the Dijle and Amblève catchments (Belgium) and the Valdaine Region (France). We consider tipping points to be a specific type of threshold, defined as relatively rapid and irreversible changes in the system. Field data demonstrate that fluvial style has varied in all three catchments over time, and that different tipping points can be identified. An increase in sediment load as a result of human induced soil erosion lead to a permanent change in the Dijle floodplains from a forested peaty marsh towards open landscape with clastic deposition and a well-defined river channel. In the Valdaine catchment, an increase in coarse sediment load, caused by increased erosion in the mountainous upper catchment, altered the floodplains from a meandering pattern to a braided pattern. Other changes in fluvial style appeared to be reversible. Rivers in the Valdaine were prone to different aggradation and incision phases due to changes in peak water discharge and sediment delivery, but the impact was too low for these changes to be irreversible. Likewise the Dijle River has recently be prone to an incision phase due to a clear water effect, and also this change is expected to be reversible. Finally, the Amblève River did not undergo major changes in style during the last 2000 to 5000 years, even though floodplain sedimentation rates increased tenfold during the last 600 years. Overall, these examples demonstrate how changes in fluvial style depend on the crossing of thresholds in sediment supply and water discharge. Although changes in these controlling parameters are caused by anthropogenic land use changes, the link between those land use changes and changes in fluvial style is not linear. This is due to the temporal variability in landscape connectivity and sediment transport and the non-linear relationship between land use intensity and soil

  18. Salinity-dependent nickel accumulation and oxidative stress responses in the euryhaline killifish (Fundulus heteroclitus).

    PubMed

    Blewett, Tamzin A; Wood, Chris M

    2015-02-01

    The mechanisms of nickel (Ni) toxicity in marine fish remain unclear, although evidence from freshwater (FW) fish suggests that Ni can act as a pro-oxidant. This study investigated the oxidative stress effects of Ni on the euryhaline killifish (Fundulus heteroclitus) as a function of salinity. Killifish were exposed to sublethal levels (5, 10, and 20 mg L(-1)) of waterborne Ni for 96 h in FW (0 ppt) and 100 % saltwater (SW) (35 ppt). In general, SW was protective against both Ni accumulation and indicators of oxidative stress [protein carbonyl formation and catalase (CAT) activity]. This effect was most pronounced at the highest Ni exposure level. For example, FW intestine showed increased Ni accumulation relative to SW intestine at 20 mg Ni L(-1), and this was accompanied by significantly greater protein carbonylation and CAT activity in this tissue. There were exceptions, however, in that although liver of FW killifish at the highest exposure concentration showed greater Ni accumulation relative to SW liver, levels of CAT activity were greatly decreased. This may relate to tissue- and salinity-specific differences in oxidative stress responses. The results of the present study suggest (1) that there was Ni-induced oxidative stress in killifish, (2) that the effects of salinity depend on differences in the physiology of the fish in FW versus SW, and (3) that increased levels of cations (sodium, calcium, potassium, and magnesium) and anions (SO4 and Cl) in SW are likely protective against Ni accumulation in tissues exposed to the aquatic environment.

  19. Effect of diurnal temperature difference on lipid accumulation and development in Calanus sinicus (Copepoda: Calanoida)

    NASA Astrophysics Data System (ADS)

    Zhou, Konglin; Sun, Song

    2017-07-01

    Calanus sinicus, the dominant copepod in the Yellow Sea, develops a large oil sac in late spring to prepare for over-summering in the Yellow Sea Cold Water Mass (YSCWM). The lipid accumulation mechanism for the initiation of over-summering is unknown. Here, we cultured C3 copepodites at four constant temperatures (10, 13, 16, and 19°C) and at three temperature regimes that mimicked the temperature variations experienced during diurnal vertical migration (10-13°C, 10-16°C, and 10-19°C) for 18 days to explore the effects of temperature differences on copepod development and lipid accumulation. C. sinicus stored more lipid at low than at high temperatures. A diurnal temperature difference (10-16°C and 10-19°C) promoted greater lipid accumulation (1.9-2.1 times) than a constant temperature of either 16°C or 19°C, by reducing the energy cost at colder temperatures and lengthening copepodite development. Thereafter, the lipid reserve supported gonad development after final molting. Only one male developed in these experiments. This highly female-skewed sex ratio may have been the result of the monotonous microalgae diet fed to the copepodites. This study provides the first evidence that diurnal temperature differences may promote lipid accumulation in C. sinicus, and provides a foundation for future investigations into the mechanisms involved in over-summering in the YSCWM.

  20. Do Child Development Accounts Promote Account Holding, Saving, and Asset Accumulation for Children's Future? Evidence from a Statewide Randomized Experiment

    ERIC Educational Resources Information Center

    Nam, Yunju; Kim, Youngmi; Clancy, Margaret; Zager, Robert; Sherraden, Michael

    2013-01-01

    This study examines the impacts of Child Development Accounts (CDAs) on account holding, saving, and asset accumulation for children, using data from the SEED for Oklahoma Kids experiment (SEED OK). SEED OK, a policy test of universal and progressive CDAs, provides a 529 college savings plan account to every infant in the treatment group with…

  1. Characteristic of nitrous oxide production in partial denitrification process with high nitrite accumulation.

    PubMed

    Du, Rui; Peng, Yongzhen; Cao, Shenbin; Wang, Shuying; Niu, Meng

    2016-03-01

    Nitrous oxide (N2O) production during the partial denitrification process with nitrate (NO3(-)-N) to nitrite (NO2(-)-N) transformation ratio of 80% was investigated in this study. Results showed that N2O was seldom observed before complete depletion of NO3(-)-N, but it was closely related to the reduction of NO2(-)-N rather than NO3(-)-N. High COD/NO3(-)-N was in favor of N2O production in partial denitrification with high NO2(-)-N accumulation. It was seriously enhanced at constant acidic pH due to the free nitrous acid (FNA) inhibition. However, the N2O production was much lower at initial pH of 5.5 and 6.5 due to the pH increase during denitrification process. Significantly, the pH turning point could be chosen as a controlled parameter to denote the end of NO3(-)-N reduction, which could not only achieve high NO2(-)-N accumulation but also decrease the N2O production significantly for practical application. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. [The added value of information summaries supporting clinical decisions at the point-of-care.

    PubMed

    Banzi, Rita; González-Lorenzo, Marien; Kwag, Koren Hyogene; Bonovas, Stefanos; Moja, Lorenzo

    2016-11-01

    Evidence-based healthcare requires the integration of the best research evidence with clinical expertise and patients' values. International publishers are developing evidence-based information services and resources designed to overcome the difficulties in retrieving, assessing and updating medical information as well as to facilitate a rapid access to valid clinical knowledge. Point-of-care information summaries are defined as web-based medical compendia that are specifically designed to deliver pre-digested, rapidly accessible, comprehensive, and periodically updated information to health care providers. Their validity must be assessed against marketing claims that they are evidence-based. We periodically evaluate the content development processes of several international point-of-care information summaries. The number of these products has increased along with their quality. The last analysis done in 2014 identified 26 products and found that three of them (Best Practice, Dynamed e Uptodate) scored the highest across all evaluated dimensions (volume, quality of the editorial process and evidence-based methodology). Point-of-care information summaries as stand-alone products or integrated with other systems, are gaining ground to support clinical decisions. The choice of one product over another depends both on the properties of the service and the preference of users. However, even the most innovative information system must rely on transparent and valid contents. Individuals and institutions should regularly assess the value of point-of-care summaries as their quality changes rapidly over time.

  3. Determinants of reinforcer accumulation during an operant task.

    PubMed Central

    McFarland, J M; Lattal, K A

    2001-01-01

    Responses by rats on an earn lever made available food pellets that were delivered to a food cup by responses on a second, collect, lever. The rats could either collect and immediately consume or accumulate (defined as the percentage of multiple earn responses and as the number of pellets earned before a collect response) earned pellets. In Experiment 1, accumulation varied as a function of variations in the earn or collect response requirements and whether the earn and collect levers were proximal (31 cm) or distal (248 cm) to one another. Some accumulation occurred under all but one of the conditions, but generally was higher when the earn and collect levers were distal to one another, particularly when the earn response requirement was fixed-ratio (FR) 1. In Experiment 2, the contributions of responses and time to accumulation were assessed by comparing an FR 20 earn response requirement to a condition in which only a single earn response was required at the end of a time interval nominally yoked to the FR interval. When 248 cm separated the earn and collect levers, accumulation was always greater in the FR condition, and it was not systematically related to reinforcement rate. In Experiment 3, increasing the earn response requirement with a progressive-ratio schedule that reset only with a collect response increased the likelihood of accumulation when the collect and earn levers were 248 cm apart, even though such accumulation increased the next earn response requirement. Reinforcer accumulation is an understudied dimension of operant behavior that relates to the analysis of such phenomena as hoarding and self-control, in that they too involve accumulating versus immediately collecting or consuming reinforcers. PMID:11768714

  4. Racial Differences in Patterns of Wealth Accumulation

    ERIC Educational Resources Information Center

    Gittleman, Maury; Wolff, Edward N.

    2004-01-01

    The race differences in patterns of asset accumulations were examined using PSD data for 1984, 1989 and 1994. The results indicate that inheritances led to wealth accumulations among whites as compared to the African Americans.

  5. Single Service Points in Libraries: A Review

    ERIC Educational Resources Information Center

    Frederiksen, Linda; Wilkinson, Brandon

    2016-01-01

    As libraries of all types and sizes continue to re-envision themselves to remain relevant in a rapidly changing information landscape, the single service point is visible evidence of this effort. In a complex environment, combining formerly disparate functional or service units is for many libraries both an innovative and effective way to manage…

  6. Evaluation of a new chest physiotherapy technique in dogs with airway fluid accumulation hospitalized in an intensive care unit.

    PubMed

    Pouzot-Nevoret, Céline; Goy-Thollot, Isabelle; Billet, Didier; Barthélemy, Anthony; Blesch, Maïlys; Pin, Aurélie; Hopper, Kate

    2018-05-01

    To evaluate the feasibility, benefits, and adverse effects of prolonged slow expiration (PSE) and assisted cough (AC) as chest physiotherapy (CP) techniques in dogs with airway fluid accumulation. Prospective interventional study. University teaching hospital. Intervention group of 30 client-owned dogs and retrospective control group of 71 client-owned dogs. PSE was performed on dogs with evidence of airway fluid accumulation, identified based on physical examination and thoracic radiographs. AC was performed if spontaneous cough or swallowing were not evident. The PSE treatment was performed every 6 hours until normalization of respiratory status or hospital discharge. Animals were monitored for respiratory distress, discomfort, and SpO 2 during the procedure. A retrospective control group was identified by computer search. One hundred thirty-three sessions of CP were performed on 30 dogs. Discomfort frequency during physiotherapy was low (9%). The most commonly used position for CP was in lateral recumbency (95%) and this was well tolerated in most cases. There was no significant difference in the median SpO 2 before and after CP sessions (P = 0.24). Sixty percent of sessions had a spontaneous cough or swallowing evident, 21% had successful AC performed, and no cough or swallowing occurred in the remaining (19%) sessions despite attempts of AC being made. The length of hospitalization was significantly longer in the intervention group (6 days vs 4) (P = 0.02). There was no difference in survival between the intervention (76.7%) and the control (57.7%) group (P = 0.055). PSE associated with AC are easily adaptable, well-tolerated techniques in dogs. The benefit of CP in dogs with airway fluid accumulation remains to be determined and it is hoped that future randomized controlled prospective studies may help answer this line of inquiry. © Veterinary Emergency and Critical Care Society 2018.

  7. Mutation of a Rice Gene Encoding a Phenylalanine Biosynthetic Enzyme Results in Accumulation of Phenylalanine and Tryptophan[W

    PubMed Central

    Yamada, Tetsuya; Matsuda, Fumio; Kasai, Koji; Fukuoka, Shuichi; Kitamura, Keisuke; Tozawa, Yuzuru; Miyagawa, Hisashi; Wakasa, Kyo

    2008-01-01

    Two distinct biosynthetic pathways for Phe in plants have been proposed: conversion of prephenate to Phe via phenylpyruvate or arogenate. The reactions catalyzed by prephenate dehydratase (PDT) and arogenate dehydratase (ADT) contribute to these respective pathways. The Mtr1 mutant of rice (Oryza sativa) manifests accumulation of Phe, Trp, and several phenylpropanoids, suggesting a link between the synthesis of Phe and Trp. Here, we show that the Mtr1 mutant gene (mtr1-D) encodes a form of rice PDT with a point mutation in the putative allosteric regulatory region of the protein. Transformed callus lines expressing mtr1-D exhibited all the characteristics of Mtr1 callus tissue. Biochemical analysis revealed that rice PDT possesses both PDT and ADT activities, with a preference for arogenate as substrate, suggesting that it functions primarily as an ADT. The wild-type enzyme is feedback regulated by Phe, whereas the mutant enzyme showed a reduced feedback sensitivity, resulting in Phe accumulation. In addition, these observations indicate that rice PDT is critical for regulating the size of the Phe pool in plant cells. Feeding external Phe to wild-type callus tissue and seedlings resulted in Trp accumulation, demonstrating a connection between Phe accumulation and Trp pool size. PMID:18487352

  8. Seasonality of snow accumulation at Mount Wrangell, Alaska, USA

    NASA Astrophysics Data System (ADS)

    Kanamori, Syosaku; Benson, Carl S.; Truffer, Martin; Matoba, Sumito; Solie, Daniel J.; Shiraiwa, Takayuki

    We recorded the burial times of temperature sensors mounted on a specially constructed tower to determine snow accumulation during individual storms in the summit caldera of Mount Wrangell, Alaska, USA, (62°N, 144°W; 4100 m a.s.l.) during the accumulation year June 2005 to June 2006. The experiment showed most of the accumulation occurred in episodic large storms, and half of the total accumulation was delivered in late summer. The timing of individual events correlated well with storms recorded upwind, at Cordova, the closest Pacific coastal weather station (200 km south-southeast), although the magnitude of events showed only poor correlation. Hence, snow accumulation at Mount Wrangell appears to be a reflection of synoptic-scale regional weather systems. The accumulation at Mount Wrangell's summit (>2.5 m w.e.) exceeded the precipitation at Cordova. Although the direct relationship between accumulation of individual storms at the summit of Mount Wrangell and precipitation events at Cordova may be unique in the region, it is useful for interpreting ice cores obtained on Mount Wrangell. This is especially the case here because the high rate of accumulation allows high time resolution within the core.

  9. Extending systematic reviews to include evidence on implementation: methodological work on a review of community-based initiatives to prevent injuries.

    PubMed

    Roen, Katrina; Arai, Lisa; Roberts, Helen; Popay, Jennie

    2006-08-01

    Unintentional injury is a leading cause of mortality and disability among young and old. While evidence about the effectiveness of interventions in reducing injuries is accumulating, reviews of this evidence frequently fail to include details of implementation processes. Our research, of which the work reported here formed a part, had two main objectives: (1) to identify evidence about the implementation of interventions aimed at reducing unintentional injuries amongst children and young people; and (2) to explore methods for systematically reviewing evidence on implementation. Existing systematic reviews of the effectiveness of interventions aiming to reduce unintentional injuries in children and young people formed the starting point for the work reported here. In summary, many of the published papers we identified contained little information on implementation processes and, even when these were discussed, the extent to which authors' claims were based on research evidence was unclear. On the basis of the studies we reviewed implementation data were insufficiently strong to provide a sound evidence base for practitioners and policymakers. Notwithstanding this, we identified valuable data about the context in which such initiatives are implemented and the type of factors that might impinge on implementation. This work has implications in three areas: (1) researchers with an interest in evidence-based public health could be encouraged to consider implementation issues in the design of intervention studies; (2) funding bodies could be encouraged to prioritise intervention studies using mixed methods that will enable researchers to consider effectiveness and implementation; (3) journal editors could work towards increasing the quality of reporting on implementation issues through the development of guidelines.

  10. A Process-Based Model of TCA Cycle Functioning to Analyze Citrate Accumulation in Pre- and Post-Harvest Fruits.

    PubMed

    Etienne, Audrey; Génard, Michel; Bugaud, Christophe

    2015-01-01

    Citrate is one of the most important organic acids in many fruits and its concentration plays a critical role in organoleptic properties. The regulation of citrate accumulation throughout fruit development, and the origins of the phenotypic variability of the citrate concentration within fruit species remain to be clarified. In the present study, we developed a process-based model of citrate accumulation based on a simplified representation of the TCA cycle to predict citrate concentration in fruit pulp during the pre- and post-harvest stages. Banana fruit was taken as a reference because it has the particularity of having post-harvest ripening, during which citrate concentration undergoes substantial changes. The model was calibrated and validated on the two stages, using data sets from three contrasting cultivars in terms of citrate accumulation, and incorporated different fruit load, potassium supply, and harvest dates. The model predicted the pre and post-harvest dynamics of citrate concentration with fairly good accuracy for the three cultivars. The model suggested major differences in TCA cycle functioning among cultivars during post-harvest ripening of banana, and pointed to a potential role for NAD-malic enzyme and mitochondrial malate carriers in the genotypic variability of citrate concentration. The sensitivity of citrate accumulation to growth parameters and temperature differed among cultivars during post-harvest ripening. Finally, the model can be used as a conceptual basis to study citrate accumulation in fleshy fruits and may be a powerful tool to improve our understanding of fruit acidity.

  11. Accumulation of Content Validation Evidence for the Critical Thinking Self-Assessment Scale.

    PubMed

    Nair, Girija Gopinathan; Hellsten, Laurie-Ann M; Stamler, Lynnette Leeseberg

    2017-04-01

    Critical thinking skills (CTS) are essential for nurses; assessing students' acquisition of these skills is a mandate of nursing curricula. This study aimed to develop a self-assessment instrument of critical thinking skills (Critical Thinking Self-Assessment Scale [CTSAS]) for students' self-monitoring. An initial pool of 196 items across 6 core cognitive skills and 16 subskills were generated using the American Philosophical Association definition of CTS. Experts' content review of the items and their ratings provided evidence of content relevance using the item-level content validity index (I-CVI) and Aiken's content validity coefficient (VIk). 115 items were retained (range of I-CVI values = .70 to .94 and range of VIk values = .69-.95; significant at p< .05). The CTSAS is the first CTS instrument designed specifically for self-assessment purposes.

  12. Divergent Evolutionary Pattern of Sugar Transporter Genes is Associated with the Difference in Sugar Accumulation between Grasses and Eudicots.

    PubMed

    Wang, Wei; Zhou, Hui; Ma, Baiquan; Owiti, Albert; Korban, Schuyler S; Han, Yuepeng

    2016-06-30

    Sugars play a variety of roles in plants, and their accumulation in seeds and/or surrounding pericarp tissues is distinctly different between grasses and eudicots. However, little is known about the evolutionary pattern of genes involved in sugar accumulation in these two major groups of flowering plants. Here, we compared evolutionary rates, gene duplication, and selective patterns of genes involved in sugar metabolism and transport between grasses and eudicots using six grass species and seven eudicot species as materials. Overall, sugar transporter genes exhibit divergent evolutionary patterns, whereas, sugar metabolism genes showing similar evolutionary pattern between monocots and eudicots. Sugar transporter genes have higher frequencies of recent duplication in eudicots than in grasses and their patterns of evolutionary rate are different. Evidence for divergent selection of these two groups of flowering plants is also observed in sugar transporter genes, wherein, these genes have undergone positive selection in eudicots, but not in grasses. Taken together, these findings suggest that sugar transporter genes rather than sugar metabolism genes play important roles in sugar accumulation in plants, and that divergent evolutionary patterns of sugar transporter genes are associated with the difference of sugar accumulation in storage tissues of grasses and eudicots.

  13. Mineral accumulation in vegetative and reproductive tissues during seed development in Medicago truncatula

    PubMed Central

    Garcia, Christina B.; Grusak, Michael A.

    2015-01-01

    Enhancing nutrient density in legume seeds is one of several strategies being explored to improve the nutritional quality of the food supply. In order to develop crop varieties with increased seed mineral concentration, a more detailed understanding of mineral translocation within the plant is required. By studying mineral accumulation in different organs within genetically diverse members of the same species, it may be possible to identify variable traits that modulate seed mineral concentration. We utilized two ecotypes (A17 and DZA315.16) of the model legume, Medicago truncatula, to study dry mass and mineral accumulation in the leaves, pod walls, and seeds during reproductive development. The pod wall dry mass was significantly different between the two ecotypes beginning at 12 days after pollination, whereas there was no significant difference in the average dry mass of individual seeds between the two ecotypes at any time point. There were also no significant differences in leaf dry mass between ecotypes; however, we observed expansion of A17 leaves during the first 21 days of pod development, while DZA315.16 leaves did not display a significant increase in leaf area. Mineral profiling of the leaves, pod walls, and seeds highlighted differences in accumulation patterns among minerals within each tissue as well as genotypic differences with respect to individual minerals. Because there were differences in the average seed number per pod, the total seed mineral content per pod was generally higher in A17 than DZA315.16. In addition, mineral partitioning to the seeds tended to be higher in A17 pods. These data revealed that mineral retention within leaves and/or pod walls might attenuate mineral accumulation within the seeds. As a result, strategies to increase seed mineral content should include approaches that will enhance export from these tissues. PMID:26322063

  14. Evidence-Based Teaching: Rhetoric and Reality

    ERIC Educational Resources Information Center

    Wrigley, Terry

    2015-01-01

    This essay connects a number of recent books relating, in different ways, to the contentious issue of how teaching might be better guided by research evidence. In order to shed light on this problematic area, Terry Wrigley begins by pointing out that raising awkward questions about terms such as "evidence- based teaching" is not the same…

  15. Chimpanzees (Pan troglodytes) Transfer Tokens Repeatedly with a Partner to Accumulate Rewards in a Self-Control Task

    PubMed Central

    Parrish, Audrey E.; Perdue, Bonnie M.; Evans, Theodore A.; Beran, Michael J.

    2013-01-01

    There has been extensive research investigating self-control in humans and nonhuman animals, yet we know surprisingly little about how one’s social environment influences self-control. The present study examined the self-control of chimpanzees in a task that required active engagement with conspecifics. The task consisted of transferring a token back and forth with a partner animal in order to accumulate food rewards, one item per token transfer. Self-control was required because at any point in the trial, either chimpanzee could obtain their accumulated rewards, but doing so discontinued the food accumulation and ended the trial for both individuals. Chimpanzees readily engaged the task and accumulated the majority of available rewards before ending each trial, and they did so across a number of conditions that varied the identity of the partner, the presence/absence of the experimenter, and the means by which they could obtain rewards. A second experiment examined chimpanzees’ self-control when given the choice between immediately available food items and a potentially larger amount of rewards that could be obtained by engaging the token transfer task with a partner. Chimpanzees were flexible in their decision-making in this test, typically choosing the option representing the largest amount of food, even if it involved delayed accumulation of the rewards via the token transfer task. These results demonstrate that chimpanzees can exhibit self-control in situations involving social interactions, and they encourage further research into this important aspect of the self-control scenario. PMID:23381691

  16. Exploring the reference point in prospect theory: gambles for length of life.

    PubMed

    van Osch, Sylvie M C; van den Hout, Wilbert B; Stiggelbout, Anne M

    2006-01-01

    Attitude toward risk is an important factor determining patient preferences. Risk behavior has been shown to be strongly dependent on the perception of the outcome as either a gain or a loss. According to prospect theory, the reference point determines how an outcome is perceived. However, no theory on the location of the reference point exists, and for the health domain, there is no direct evidence for the location of the reference point. This article combines qualitative with quantitative data to provide evidence of the reference point in life-year certainty equivalent (CE) gambles and to explore the psychology behind the reference point. The authors argue that goals (aspirations) in life influence the reference point. While thinking aloud, 45 healthy respondents gave certainty equivalents for life-year CE gambles with long and short durations of survival. Contrary to suggestions from the literature, qualitative data argued that the offered certainty equivalent most frequently served as the reference point. Thus, respondents perceived life-year CE gambles as mixed. Framing of the question and goals set in life appeared to be important factors behind the psychology of the reference point. On the basis of the authors' quantitative and qualitative data, they argue that goals alter the perception of outcomes as described by prospect theory by influencing the reference point. This relationship is more apparent for the near future as opposed to the remote future, as goals are mostly set for the near future.

  17. Amyloid and intracellular accumulation of BRI2.

    PubMed

    Garringer, Holly J; Sammeta, Neeraja; Oblak, Adrian; Ghetti, Bernardino; Vidal, Ruben

    2017-04-01

    Familial British dementia (FBD) and familial Danish dementia (FDD) are caused by mutations in the BRI 2 gene. These diseases are characterized clinically by progressive dementia and ataxia and neuropathologically by amyloid deposits and neurofibrillary tangles. Herein, we investigate BRI 2 protein accumulation in FBD, FDD, Alzheimer disease and Gerstmann-Sträussler-Scheinker disease. In FBD and FDD, we observed reduced processing of the mutant BRI 2 pro-protein, which was found accumulating intracellularly in the Golgi of neurons and glial cells. In addition, we observed an accumulation of a mature form of BRI 2 protein in dystrophic neurites, surrounding amyloid cores. Accumulation of BRI 2 was also observed in dystrophic neurites of Alzheimer disease and Gerstmann-Sträussler-Scheinker disease cases. Although it remains to be determined whether intracellular accumulation of BRI 2 may lead to cell damage in these degenerative diseases, our study provides new insights into the role of mutant BRI 2 in the pathogenesis of FBD and FDD and implicates BRI 2 as a potential indicator of neuritic damage in diseases characterized by cerebral amyloid deposition. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. Amyloid and intracellular accumulation of BRI2

    PubMed Central

    Garringer, Holly J.; Sammeta, Neeraja; Oblak, Adrian; Ghetti, Bernardino; Vidal, Ruben

    2016-01-01

    Familial British dementia (FBD) and familial Danish dementia (FDD) are caused by mutations in the BRI2 gene. These diseases are characterized clinically by progressive dementia and ataxia and neuropathologically by amyloid deposits and neurofibrillary tangles. Herein, we investigate BRI2 protein accumulation in FBD, FDD, Alzheimer disease and Gerstmann-Sträussler-Scheinker disease. In FBD and FDD, we observed reduced processing of the mutant BRI2 pro-protein, which was found accumulating intracellularly in the Golgi of neurons and glial cells. In addition, we observed an accumulation of a mature form of BRI2 protein in dystrophic neurites, surrounding amyloid cores. Accumulation of BRI2 was also observed in dystrophic neurites of Alzheimer disease and Gerstmann-Sträussler-Scheinker disease cases. Although it remains to be determined whether intracellular accumulation of BRI2 may lead to cell damage in these degenerative diseases, our study provides new insights into the role of mutant BRI2 in the pathogenesis of FBD and FDD and implicates BRI2 as a potential indicator of neuritic damage in diseases characterized by cerebral amyloid deposition. PMID:28131015

  19. Earliest accumulation history of the north polar layered deposits, Mars from SHARAD

    NASA Astrophysics Data System (ADS)

    Nerozzi, Stefano; Holt, John W.

    2018-07-01

    The approximately 2 km thick north polar layered deposits (NPLD) are often considered to contain the most complete and detailed stratigraphic records of recent climate of Mars. Exposures of the dense layering within troughs and scarps allowed detailed reconstructions of the latest accumulation history of these water ice deposits, but we lack knowledge of their initial emplacement. The Shallow Radar (SHARAD) onboard Mars Reconnaissance Orbiter (MRO) penetrates the NPLD to their base and detects their internal layering, overcoming the limitation of scarce and scattered visible outcrops of the lowermost sequences. In this study, we map reflectors in SHARAD data that result from discrete stratigraphic horizons in order to delineate the three-dimensional stratigraphy of the lowermost ∼500 m NPLD sequence and reconstruct their accumulation history. We confirm the large-scale lateral continuity and thickness uniformity of the deposits previously detected within the lowermost NPLD. However, stratigraphic complexity-in the form of pinch-outs and significant thickness variations-arises when we examine single radar units. We find evidence of an initially limited geographic stability of water ice within two deposits that are centered at the North Pole and present-day Gemina Lingula. A period of lateral ice sheet growth followed, interrupted only once by a retreat episode. Lower net accumulation is observed on pre-existing slopes, suggesting a reduction of water ice stability due to increased solar radiation incidence and/or transport by katabatic winds. Lateral transport of water ice by wind is also suggested by thickness undulations toward the top of the sequence, resembling cyclic steps. Water ice accumulation models based on orbital forcing predict a sequence of deposition and retreat events that is generally compatible with our reconstructed accumulation history. Therefore, we interpret the stratigraphic complexity that we observe as regional and, possibly global

  20. Accumulation of unsaturated lipids in monocytes during early phase pyrogen tolerance.

    PubMed

    Szewczenko-Pawlikowski, M; Kozak, W

    2000-04-12

    This paper presents data that inspired a new explanation for the mechanism of early phase endotoxin tolerance. Rabbits injected intravenously with LPS from Salmonella abortus developed a two-phase fever (6 h) and monophasic hyperlipidemia of very low density lipoproteins (two consecutive days). If during these days rabbits were injected with the same dose of LPS at 24-h intervals, the second phase of fever disappeared, i.e. early phase pyrogenic tolerance was obtained. This was correlated with a decrease of lipoprotein hyperlipidemia (measured 1.5 h after LPS injection) and an accumulation of lipids rich in double bonds in monocytes (measured 3.5 h after LPS injection). Results showed that the degree of unsaturation of acyl chains (AC) in monocytes (AC/DB, DB=double bonds) is negatively correlated (r=-0.72) with fever response (fever index). The authors maintain that a gradual increase in monocyte membrane fluidity is an adaptation to repeated exposure of monocytes to lipid A and is responsible for the progressive desensitization of monocytes to endotoxin. It is suggested that disorders of this mechanism lead to an accumulation of abnormal quantities of saturated lipids and cholesterol within macrophages, which, as foam cells, are the starting point for atherosclerosis pathology.

  1. Lipid droplets accumulation and other biochemical changes induced in the fungal pathogen Ustilago maydis under nitrogen-starvation.

    PubMed

    Aguilar, Lucero Romero; Pardo, Juan Pablo; Lomelí, Mónica Montero; Bocardo, Oscar Ivan Luqueño; Juárez Oropeza, Marco A; Guerra Sánchez, Guadalupe

    2017-10-01

    In many organisms, the growth under nitrogen-deprivation or a poor nitrogen source impacts on the carbon flow distribution and causes accumulation of neutral lipids, which are stored as lipid droplets (LDs). Efforts are in progress to find the mechanism of LDs synthesis and degradation, and new organisms capable of accumulating large amounts of lipids for biotechnological applications. In this context, when Ustilago maydis was cultured in the absence of a nitrogen source, there was a large accumulation of lipid bodies containing mainly triacylglycerols. The most abundant fatty acids in lipid bodies at the stationary phase were palmitic, linoleic, and oleic acids, and they were synthesized de novo by the fatty-acid synthase. In regard to the production of NADPH for the synthesis of fatty acids, the cytosolic NADP + -dependent isocitrate dehydrogenase and the glucose-6-phosphate and 6-phosphogluconate dehydrogenases couple showed the highest specific activities, with a lower activity of the malic enzyme. The ATP-citrate lyase activity was not detected in any of the culture conditions, which points to a different mechanism for the transfer of acetyl-CoA into the cytosol. Protein and RNA contents decreased when U. maydis was grown without a nitrogen source. Due to the significant accumulation of triacylglycerols and the particular composition of fatty acids, U. maydis can be considered an alternative model for biotechnological applications.

  2. Comparative transcriptome analysis to investigate the high starch accumulation of duckweed (Landoltia punctata) under nutrient starvation.

    PubMed

    Tao, Xiang; Fang, Yang; Xiao, Yao; Jin, Yan-Ling; Ma, Xin-Rong; Zhao, Yun; He, Kai-Ze; Zhao, Hai; Wang, Hai-Yan

    2013-05-08

    Duckweed can thrive on anthropogenic wastewater and produce tremendous biomass production. Due to its relatively high starch and low lignin percentage, duckweed is a good candidate for bioethanol fermentation. Previous studies have observed that water devoid of nutrients is good for starch accumulation, but its molecular mechanism remains unrevealed. This study globally analyzed the response to nutrient starvation in order to investigate the starch accumulation in duckweed (Landoltia punctata). L. punctata was transferred from nutrient-rich solution to distilled water and sampled at different time points. Physiological measurements demonstrated that the activity of ADP-glucose pyrophosphorylase, the key enzyme of starch synthesis, as well as the starch percentage in duckweed, increased continuously under nutrient starvation. Samples collected at 0 h, 2 h and 24 h time points respectively were used for comparative gene expression analysis using RNA-Seq. A comprehensive transcriptome, comprising of 74,797 contigs, was constructed by a de novo assembly of the RNA-Seq reads. Gene expression profiling results showed that the expression of some transcripts encoding key enzymes involved in starch biosynthesis was up-regulated, while the expression of transcripts encoding enzymes involved in starch consumption were down-regulated, the expression of some photosynthesis-related transcripts were down-regulated during the first 24 h, and the expression of some transporter transcripts were up-regulated within the first 2 h. Very interestingly, most transcripts encoding key enzymes involved in flavonoid biosynthesis were highly expressed regardless of starvation, while transcripts encoding laccase, the last rate-limiting enzyme of lignifications, exhibited very low expression abundance in all three samples. Our study provides a comprehensive expression profiling of L. punctata under nutrient starvation, which indicates that nutrient starvation down-regulated the global metabolic

  3. Comparative transcriptome analysis to investigate the high starch accumulation of duckweed (Landoltia punctata) under nutrient starvation

    PubMed Central

    2013-01-01

    Background Duckweed can thrive on anthropogenic wastewater and produce tremendous biomass production. Due to its relatively high starch and low lignin percentage, duckweed is a good candidate for bioethanol fermentation. Previous studies have observed that water devoid of nutrients is good for starch accumulation, but its molecular mechanism remains unrevealed. Results This study globally analyzed the response to nutrient starvation in order to investigate the starch accumulation in duckweed (Landoltia punctata). L. punctata was transferred from nutrient-rich solution to distilled water and sampled at different time points. Physiological measurements demonstrated that the activity of ADP-glucose pyrophosphorylase, the key enzyme of starch synthesis, as well as the starch percentage in duckweed, increased continuously under nutrient starvation. Samples collected at 0 h, 2 h and 24 h time points respectively were used for comparative gene expression analysis using RNA-Seq. A comprehensive transcriptome, comprising of 74,797 contigs, was constructed by a de novo assembly of the RNA-Seq reads. Gene expression profiling results showed that the expression of some transcripts encoding key enzymes involved in starch biosynthesis was up-regulated, while the expression of transcripts encoding enzymes involved in starch consumption were down-regulated, the expression of some photosynthesis-related transcripts were down-regulated during the first 24 h, and the expression of some transporter transcripts were up-regulated within the first 2 h. Very interestingly, most transcripts encoding key enzymes involved in flavonoid biosynthesis were highly expressed regardless of starvation, while transcripts encoding laccase, the last rate-limiting enzyme of lignifications, exhibited very low expression abundance in all three samples. Conclusion Our study provides a comprehensive expression profiling of L. punctata under nutrient starvation, which indicates that nutrient starvation down

  4. Molybdenum accumulation, tolerance and molybdenum-selenium-sulfur interactions in Astragalus selenium hyperaccumulator and nonaccumulator species.

    PubMed

    DeTar, Rachael Ann; Alford, Élan R; Pilon-Smits, Elizabeth A H

    2015-07-01

    Some species hyperaccumulate selenium (Se) upwards of 0.1% of dry weight. This study addressed whether Se hyperaccumulators also accumulate and tolerate more molybdenum (Mo). A field survey revealed on average 2-fold higher Mo levels in three hyperaccumulator Astragali compared to three nonaccumulator Astragali, which were not significantly different. Next, a controlled study was performed where hyperaccumulators Astragalus racemosus and Astragalus bisulcatus were compared with nonaccumulators Astragalus drummondii and Astragalus convallarius for Mo accumulation and tolerance, alone or in the presence of Se. When grown on agar media with 0, 12, 24 or 48 mg L(-1) molybdate and/or 0, 1.6 or 3.2 mg L(-1) selenate, all species decreased in biomass with increasing Mo supply. Selenium did not impact biomass at the supplied levels. All Astragali accumulated Mo upwards of 0.1% of dry weight. Selenium levels were up to 0.08% in Astragalus racemosus and 0.04% Se in the other species. Overall, there was no correlation between Se hyperaccumulation and Mo accumulation capacity. However, the hyperaccumulators and nonaccumulators differed in some respects. While none of the species had a higher tissue Mo to sulfur (S) ratio than the growth medium, nonaccumulators had a higher Mo/S ratio than hyperaccumulators. Also, while molybdate and selenate reduced S accumulation in nonaccumulators, it did not in hyperaccumulators. Furthermore, A. racemosus had a higher Se/S ratio than its medium, while the other species did not. Additionally, Mo and Se treatment affected S levels in nonaccumulators, but not in hyperaccumulators. In conclusion, there is no evidence of a link between Se and Mo accumulation and tolerance in Astragalus. Sulfate transporters in hyperaccumulating Astragali appear to have higher sulfate specificity over other oxyanions, compared to nonaccumulators, and A. racemosus may have a transporter with enhanced selenate specificity relative to sulfate or molybdate. Copyright

  5. Influence of hydroxypropyl-beta-cyclodextrin on the transdermal permeation and skin accumulation of oxybenzone.

    PubMed

    Felton, Linda A; Wiley, Cody J; Godwin, Donald A

    2002-10-01

    The objective of the present study was to determine the effects of hydroxypropyl-beta-cyclodextrin (HPCD) concentration on the transdermal permeation and skin accumulation of a model ultraviolet (UV) absorber, oxybenzone. The concentration of oxybenzone was held constant at 2.67 mg/mL for all formulations, while the HPCD concentrations varied from 0 to 20% (w/w). Complexation of oxybenzone by HPCD was demonstrated by differential scanning calorimetry. A modified Franz cell apparatus was used in the transdermal experiments, with aliquots of the receptor fluid assayed for oxybenzone by high-performance liquid chromatography. From the permeation data, flux of the drug was calculated. Skins were removed from the diffusion cells at specified time points over a 24-hr period and the oxybenzone content in the skin determined. The aqueous solubility of oxybenzone increased linearly with increasing HPCD concentration, following a Higuchi AL-type complexation. The stability constant of the reaction was calculated from the phase-solubility diagram and found to be 2047 M-1. As the concentration of HPCD was increased from 0 to 10%, transdermal permeation and skin accumulation of oxybenzone increased. Maximum flux occurred at 10% HPCD, where sufficient cyclodextrin was added to completely solubilize all oxybenzone. When the concentration of HPCD was increased to 20%, both transdermal permeation and skin accumulation decreased. These data suggest the formation of a drug reservoir on the surface of the skin.

  6. Momentum accumulation due to solar radiation torque, and reaction wheel sizing, with configuration optimization

    NASA Technical Reports Server (NTRS)

    Hablani, Hari B.

    1993-01-01

    This paper has a two-fold objective: determination of yearly momentum accumulation due to solar radiation pressure, and optimum reaction wheel sizing. The first objective is confronted while determining propellant consumption by the attitude control system over a spacecraft's lifetime. This, however, cannot be obtained from the daily momentum accumulation and treating that constant throughout the year, because the orientation of the solar arrays relative to the spacecraft changes over a wide range in a year, particularly if the spacecraft has two arrays, one normal and the other off-normal to different extent at different times to the sun rays. The paper first develops commands for the arrays for tracking the sun, the arrays articulated to earth-pointing spacecraft with two rotational degrees of freedom, and spacecraft in an arbitrary circular orbit. After developing expressions for solar radiation torque due to one or both arrays, arranged symmetrically or asymmetrically relative to the spacecraft bus, momentum accumulation over an orbit and then over a year are determined. The remainder of the paper is concerned with designing reaction wheel configurations. Four-, six-, and three-wheel configurations are considered, and for given torque and momentum requirements, their cant angles with the roll/yaw plane are optimized for minimum power consumption. Finally, their momentum and torque capacities are determined for one-wheel failure scenario, and six configurations are compared and contrasted.

  7. Mechanisms of soil organic carbon accumulation from long-term fertilization strategies in two soils: Evidence from nuclear magnetic resonance spectroscopy analysis

    USDA-ARS?s Scientific Manuscript database

    Long-term fertilization strategies have been proven to significantly influence soil organic carbon (SOC) accumulation, while the underlying mechanism remains unclear. Using two long-term (>20 y) field experiments of a double-cropped maize-wheat rotation on a Calcaric Fluvisol and paddy rice on a Hyd...

  8. Host-pathogen interactions. XV. Fungal glucans which elicit phytoalexin accumulation in soybean also elicit the accumulation of phytoalexins in other plants

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

    Cline, K.; Wade, M.; Albersheim, P.

    1978-01-01

    A ..beta..-glucan isolated from the mycelial walls of Phytophthora megasperma var. sojae and a glucan purified from yeast extract stimulate the accumulation of phytoalexins in red kidney bean, Phaseolus vulgaris, and stimulate the accumulation of the phytoalexin, rishitin, in potato tubers, Solanum tuberosum. Treatment of kidney bean cotyledons with the glucan elicitors resulted in the accumulation of at least five fungistatic compounds. These compounds migrate during thin layer chromatography identically to the fungistatic compounds which accumulate in kidney beans which have been inoculated with Colletotrichum lindemuthianum, a fungal pathogen of kidney beans. Potatoes accumulate as much as 29 micrograms ofmore » rishitin per gram fresh weight following exposure to the glucan from Phytophthora megasperma va. sojae and as much as 19.5 micrograms of rishitin per gram fresh weight following exposure to yeast glucan.« less

  9. Adaptive History Biases Result from Confidence-Weighted Accumulation of past Choices

    PubMed Central

    2018-01-01

    Perceptual decision-making is biased by previous events, including the history of preceding choices: observers tend to repeat (or alternate) their judgments of the sensory environment more often than expected by chance. Computational models postulate that these so-called choice history biases result from the accumulation of internal decision signals across trials. Here, we provide psychophysical evidence for such a mechanism and its adaptive utility. Male and female human observers performed different variants of a challenging visual motion discrimination task near psychophysical threshold. In a first experiment, we decoupled categorical perceptual choices and motor responses on a trial-by-trial basis. Choice history bias was explained by previous perceptual choices, not motor responses, highlighting the importance of internal decision signals in action-independent formats. In a second experiment, observers performed the task in stimulus environments containing different levels of autocorrelation and providing no external feedback about choice correctness. Despite performing under overall high levels of uncertainty, observers adjusted both the strength and the sign of their choice history biases to these environments. When stimulus sequences were dominated by either repetitions or alternations, the individual degree of this adjustment of history bias was about as good a predictor of individual performance as individual perceptual sensitivity. The history bias adjustment scaled with two proxies for observers' confidence about their previous choices (accuracy and reaction time). Together, our results are consistent with the idea that action-independent, confidence-modulated decision variables are accumulated across choices in a flexible manner that depends on decision-makers' model of their environment. SIGNIFICANCE STATEMENT Decisions based on sensory input are often influenced by the history of one's preceding choices, manifesting as a bias to systematically repeat

  10. Adaptive History Biases Result from Confidence-weighted Accumulation of Past Choices.

    PubMed

    Braun, Anke; Urai, Anne E; Donner, Tobias H

    2018-01-25

    Perceptual decision-making is biased by previous events, including the history of preceding choices: Observers tend to repeat (or alternate) their judgments of the sensory environment more often than expected by chance. Computational models postulate that these so-called choice history biases result from the accumulation of internal decision signals across trials. Here, we provide psychophysical evidence for such a mechanism and its adaptive utility. Male and female human observers performed different variants of a challenging visual motion discrimination task near psychophysical threshold. In a first experiment, we decoupled categorical perceptual choices and motor responses on a trial-by-trial basis. Choice history bias was explained by previous perceptual choices, not motor responses, highlighting the importance of internal decision signals in action-independent formats. In a second experiment, observers performed the task in stimulus environments containing different levels of auto-correlation and providing no external feedback about choice correctness. Despite performing under overall high levels of uncertainty, observers adjusted both the strength and the sign of their choice history biases to these environments. When stimulus sequences were dominated by either repetitions or alternations, the individual degree of this adjustment of history bias was about as good a predictor of individual performance as individual perceptual sensitivity. The history bias adjustment scaled with two proxies for observers' confidence about their previous choices (accuracy and reaction time). Taken together, our results are consistent with the idea that action-independent, confidence-modulated decision variables are accumulated across choices in a flexible manner that depends on decision-makers' model of their environment. Significance statement: Decisions based on sensory input are often influenced by the history of one's preceding choices, manifesting as a bias to

  11. Moving Beyond Conventional Clinical Trial End Points in Treatment-refractory Metastatic Colorectal Cancer: A Composite Quality-of-life and Symptom Control End Point.

    PubMed

    Gong, Jun; Wu, Daniel; Chuang, Jeremy; Tuli, Richard; Simard, John; Hendifar, Andrew

    2017-11-01

    This review highlights the evidence supporting symptom control and quality-of-life (QOL) measures as predictors of survival in treatment-refractory metastatic colorectal cancer (mCRC) and describes a composite symptom control and QOL end point recently reported in a Phase III trial that may serve as a more reasonable end point of efficacy in this population. A literature search was conducted using MEDLINE to identify clinical studies (including case series and observational, retrospective, and prospective studies) that reported the predictive value of QOL measures for survival in mCRC. The search was limited by the following key words: quality of life, survival, and colorectal cancer. We then performed a second search limited to studies of randomized and Phase III design in mCRC to identify studies that used QOL assessments as their primary end points. A manual search was also performed to include additional studies of potential relevance. There is increasing evidence to support that symptom control and QOL measures are predictors of survival in treatment-refractory mCRC and can serve as an alternative but equally as important end point to survival in this population. A recent large, randomized Phase III trial using a composite primary end point of lean body mass, pain, anorexia, and fatigue reported the feasibility in evaluating benefit in mCRC beyond conventional clinical trial end points. Future studies in treatment-refractory mCRC may be better served by evaluating improvement in symptom control and QOL, which may otherwise serve as the best predictor of survival in last-line treatment settings. Copyright © 2017 Elsevier HS Journals, Inc. All rights reserved.

  12. Factors influencing the accumulation of ciprofloxacin in Pseudomonas aeruginosa.

    PubMed Central

    Celesk, R A; Robillard, N J

    1989-01-01

    Ciprofloxacin accumulation in Pseudomonas aeruginosa was measured by a bioassay. Drug accumulation in strain PAO2 was compared with that of three spontaneous ciprofloxacin-resistant mutants selected with 0.5 micrograms of ciprofloxacin per ml. PAO4701 cfxA2 contains a mutation in the gyrA gene, PAO4742 cfxB5 may represent a permeability mutant based on pleiotropic drug resistance, and PAO4700 cfxA1 cfxB1 contains both types of mutations. In all strains, drug accumulation was similar, reaching steady state during the first minute of exposure. Drug accumulation was unsaturable over a range of 5 to 80 micrograms/ml, suggesting that ciprofloxacin accumulates by diffusion in P. aeruginosa. Although all four strains accumulated two- to sevenfold more ciprofloxacin in the presence of the inhibitor carbonyl cyanide m-chlorophenylhydrazone, the cfxB mutants accumulated two- to fourfold less drug than either PAO2 or the cfxA2 mutant. Polyacrylamide gel analysis revealed a protein common to cfxB mutants only, while all strains had similar lipopolysaccharide profiles. The results suggest that ciprofloxacin accumulation in P. aeruginosa is a complex phenomenon that may be affected by both an energy-dependent drug efflux process and outer envelope composition. Images PMID:2514623

  13. In Vivo Inhibition of Lipid Accumulation in Caenorhabditis elegans

    NASA Astrophysics Data System (ADS)

    Sulistiyani; Purwakusumah, E. P.; Andrianto, D.

    2017-03-01

    This is a preliminary research report on the use of Caenorhabditis elegans as a model to establish anti-obesity screening assay of the natural plant resources. Nematode C. elegans has been used as experimental animal model for understanding lipid accumulation. The objective of this research was to investigate the effect of selected plant extracts on lipid accumulation in C. elegans. Currently no report could be found regarding lipid accumulation in C.elegans treated with ethanolic leaf extracts of jabon merah (Anthocephalus macrophyllus), jati belanda (Guazuma ulmifolia), and Mindi (Melia Azedarach) plants. Lipid accumulation was determined qualitatively using lipid staining method and quantitatively by colorimetry using sulpho-phospho-vanillin reagent. Data showed that lipid accumulation was inhibited up to 72% by extract of M. azedarach, about 35% by both of A. macrophyllus and G. ulmifolia extracts, and up to 25% by orlistat (a synthetic slimming drug). Ethanolic extract of A. macrophyllus, G. ulmifolia, and M. azedarach leaves were shown to inhibit lipid accumulation in C. elegans and M. azedarach leaves extracts was the most effective inhibitor. C.elegans were shown to be an effective model for in vivo lipid accumulation mechanism and potential to be used as a rapid screening assay for bioactive compounds with lipid accumulation inhibitory activity.

  14. Critical Points and Traveling Wave in Locomotion: Experimental Evidence and Some Theoretical Considerations.

    PubMed

    Saltiel, Philippe; d'Avella, Andrea; Tresch, Matthew C; Wyler, Kuno; Bizzi, Emilio

    2017-01-01

    The central pattern generator (CPG) architecture for rhythm generation remains partly elusive. We compare cat and frog locomotion results, where the component unrelated to pattern formation appears as a temporal grid, and traveling wave respectively. Frog spinal cord microstimulation with N-methyl-D-Aspartate (NMDA), a CPG activator, produced a limited set of force directions, sometimes tonic, but more often alternating between directions similar to the tonic forces. The tonic forces were topographically organized, and sites evoking rhythms with different force subsets were located close to the constituent tonic force regions. Thus CPGs consist of topographically organized modules. Modularity was also identified as a limited set of muscle synergies whose combinations reconstructed the EMGs. The cat CPG was investigated using proprioceptive inputs during fictive locomotion. Critical points identified both as abrupt transitions in the effect of phasic perturbations, and burst shape transitions, had biomechanical correlates in intact locomotion. During tonic proprioceptive perturbations, discrete shifts between these critical points explained the burst durations changes, and amplitude changes occurred at one of these points. Besides confirming CPG modularity, these results suggest a fixed temporal grid of anchoring points, to shift modules onsets and offsets. Frog locomotion, reconstructed with the NMDA synergies, showed a partially overlapping synergy activation sequence. Using the early synergy output evoked by NMDA at different spinal sites, revealed a rostrocaudal topographic organization, where each synergy is preferentially evoked from a few, albeit overlapping, cord regions. Comparing the locomotor synergy sequence with this topography suggests that a rostrocaudal traveling wave would activate the synergies in the proper sequence for locomotion. This output was reproduced in a two-layer model using this topography and a traveling wave. Together our results

  15. [99mTc(V)-DMSA accumulation in gynecomastia].

    PubMed

    Ohta, H

    1998-11-01

    The accumulation of 99mTc(V)-DMSA in bilateral breasts was recognized in a 60-year-old male with drug-induced gynecomastia. There are some reports describing 99mTc(V)-DMSA accumulation in normal female breast, fibrous dysplasia of the breast and metastatic lesions of breast carcinoma, but to my knowledge, there have been no reports describing 99mTc(V)-DMSA accumulation in gynecomastia.

  16. Distinctive accumulation patterns of heavy metals in Sardinella aurita (Clupeidae) and Mugil cephalus (Mugilidae) tissues.

    PubMed

    Annabi, Ali; El Mouadeb, Rahma; Herrel, Anthony

    2018-01-01

    The present study assessed the impact of metal pollution on two widely consumed types of wild fish Sardinella aurita and Mugil cephalus captured from the Gulf of Gabes (Tunisia) which is currently experiencing acute environmental problems. A study of the Cd, Cu, Zn, and Pb levels present in the studied site and vital in fish tissues (gills, liver, gonad, and muscle) was undertaken. As expected, muscle, liver, and gonad tissues contained the highest concentrations of all metals except for Zn. The metal levels showed a significant variation of accumulation between species with overall effects of the tested tissues. In addition, the results address the significant effects of the species/tissue interaction. Liver sections showed structural alterations consisting mainly of a significant desquamation of the tissue, a fibroblast proliferation, and a lipid droplet accumulation in both species. Additionally, the presence of skeletal abnormalities affecting the vertebral column was observed in the M. cephalus specimens. As a whole, our data provide the first evidence of distinctive metal accumulation patterns in vital fish tissues as well as the interspecific difference that can be correlated with the biological habits of the two selected models, S. aurita and M. cephalus, known respectively as pelagic and benthopelagic species.

  17. Unprecedented last-glacial mass accumulation rates determined by luminescence dating of loess from western Nebraska

    USGS Publications Warehouse

    Roberts, H.M.; Muhs, D.R.; Wintle, A.G.; Duller, G.A.T.; Bettis, E. Arthur

    2003-01-01

    A high-resolution chronology for Peoria (last glacial period) Loess from three sites in Nebraska, midcontinental North America, is determined by applying optically stimulated luminescence (OSL) dating to 35-50 ??m quartz. At Bignell Hill, Nebraska, an OSL age of 25,000 yr near the contact of Peoria Loess with the underlying Gilman Canyon Formation shows that dust accumulation occurred early during the last glacial maximum (LGM), whereas at Devil's Den and Eustis, Nebraska, basal OSL ages are significantly younger (18,000 and 21,000 yr, respectively). At all three localities, dust accumulation ended at some time after 14,000 yr ago. Mass accumulation rates (MARs) for western Nebraska, calculated using the OSL ages, are extremely high from 18,000 to 14,000 yr-much higher than those calculated for any other pre-Holocene location worldwide. These unprecedented MARs coincide with the timing of a mismatch between paleoenvironmental evidence from central North America, and the paleoclimate simulations from atmospheric global circulation models (AGCMs). We infer that the high atmospheric dust loading implied by these MARs may have played an important role, through radiative forcing, in maintaining a colder-than-present climate over central North America for several thousand years after summer insolation exceeded present-day values. ?? 2003 Elsevier Science (USA). All rights reserved.

  18. Evidence of leopard predation on bonobos (Pan paniscus).

    PubMed

    D'Amour, Danielle E; Hohmann, Gottfried; Fruth, Barbara

    2006-01-01

    Current models of social organization assume that predation is one of the major forces that promotes group living in diurnal primates. As large body size renders some protection against predators, gregariousness of great apes and other large primate species is usually related to other parameters. The low frequency of observed cases of nonhuman predation on great apes seems to support this assumption. However, recent efforts to study potential predator species have increasingly accumulated direct and indirect evidence of predation by leopards (Panthera pardus) on chimpanzees and gorillas. The following report provides the first evidence of predation by a leopard on bonobos (Pan paniscus). Copyright 2006 S. Karger AG, Basel.

  19. Evaluation of two models for predicting elemental accumulation by arthropods

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

    Webster, J.R.; Crossley, D.A. Jr.

    1978-06-15

    Two different models have been proposed for predicting elemental accumulation by arthropods. Parameters of both models can be quantified from radioisotope elimination experiments. Our analysis of the 2 models shows that both predict identical elemental accumulation for a whole organism, though differing in the accumulation in body and gut. We quantified both models with experimental data from /sup 134/Cs and /sup 85/Sr elimination by crickets. Computer simulations of radioisotope accumulation were then compared with actual accumulation experiments. Neither model showed exact fit to the experimental data, though both showed the general pattern of elemental accumulation.

  20. Evaluation of urban environment pollution based on the accumulation of macro- and trace elements in epiphytic lichens.

    PubMed

    Parzych, Agnieszka; Astel, Aleksander; Zduńczyk, Anna; Surowiec, Tomasz

    2016-01-01

    Nitrogen, phosphorus, potassium, magnesium, zinc, nickel, copper, manganese, iron and lead accumulation properties of three epiphytic lichen species (Hypogymnia physodes (L.) Nyl., Parmelia sulcata Taylor and Xanthoria parietina (L.) Th. Fr.) were compared. An assessment of pollution of the municipal environment in Słupsk (Poland) according to macro- and trace elements was also done. Lichen samples were taken in Autumn 2013 from Betula pendula, Fraxinus excelsior, Acer platanoides, A. pseudoplatanus and Populus sp. trees. Sampling stations comprised of house development areas, green urban parks, vicinity of streets with heavy traffic and industrial enterprises. It was found that lichens represent diverse accumulation properties to pollutants according to the species. X. parietina indicated the highest bioaccumulation in relation to N, K, Mg, Zn and Fe, the thalli of H. physodes accumulated the largest amounts of Ni and Pb, while P. sulcata P and Cu. Manganese was accumulated in similar quantities by all species. Evidences acquired by the use of factor analysis proved that pollution in Słupsk municipal environment is a serious issue with three major sources domination: street dust, marine factor and residual oil combustion. The high-risk areas were detected and visualized using surface maps based on Kriging algorithm. It was seen that the highest pollution occurs in the town centre, while the smallest happened on its outskirts and in urban parks.

  1. Anion channels and the stimulation of anthocyanin accumulation by blue light in Arabidopsis seedlings

    NASA Technical Reports Server (NTRS)

    Noh, B.; Spalding, E. P.; Evans, M. H. (Principal Investigator)

    1998-01-01

    Activation of anion channels by blue light begins within seconds of irradiation in seedlings and is related to the ensuing growth inhibition. 5-Nitro-2-(3-phenylpropylamino)-benzoic acid (NPPB) is a potent, selective, and reversible blocker of these anion channels in Arabidopsis thaliana. Here we show that 20 microM NPPB blocked 72% of the blue-light-induced accumulation of anthocyanin pigments in seedlings. Feeding biosynthetic intermediates to wild-type and tt5 seedlings provided evidence that NPPB prevented blue light from up-regulating one or more steps between and including phenylalanine ammonia lyase and chalcone isomerase. NPPB was found to have no significant effect on the blue-light-induced increase in transcript levels of PAL1, CHS, CHI, or DFR, which are genes that encode anthocyanin-biosynthetic enzymes. Immunoblots revealed that NPPB also did not inhibit the accumulation of the chalcone synthase, chalcone isomerase, or flavanone-3-hydroxylase proteins. This is in contrast to the reduced anthocyanin accumulation displayed by a mutant lacking the HY4 blue-light receptor, as hy4 displayed reduced expression of the above enzymes. Taken together, the data indicate that blue light acting through HY4 leads to an increase in the amount of biosynthetic enzymes but blue light must also act through a separate, anion-channel-dependent system to create a fully functional biosynthetic pathway.

  2. THE SOURCE OF LIPID ACCUMULATION IN L CELLS

    PubMed Central

    Bensch, Klaus G.; King, Donald W.; Socolow, Edward L.

    1961-01-01

    Strain L cells accumulate lipid, concurrent with cessation of protein synthesis, in the stationary phase of growth from the extracellular medium and as a result of de novo synthesis. Cells which have been more severely damaged with an amino acid analogue also accumulate lipid from the extracellular medium, but synthesize very little lipid from labeled acetate. The possible roles which lipid accumulation may play in the cell are discussed. PMID:19866577

  3. Total carbon accumulation in a tropical forest landscape.

    PubMed

    Sierra, Carlos A; Del Valle, Jorge I; Restrepo, Hector I

    2012-12-19

    Regrowing tropical forests worldwide sequester important amounts of carbon and restore part of the C emissions emitted by deforestation. However, there are large uncertainties concerning the rates of carbon accumulation after the abandonment of agricultural and pasture land. We report here accumulation of total carbon stocks (TCS) in a chronosequence of secondary forests at a mid-elevation landscape (900-1200 m asl) in the Andean mountains of Colombia. We found positive accumulation rates for all ecosystem pools except soil carbon, which showed no significant trend of recovery after 36 years of secondary succession. We used these data to develop a simple model to predict accumulation of TCS over time. This model performed remarkably well predicting TCS at other chronosequences in the Americas (Root Mean Square Error < 40 Mg C ha-1), which provided an opportunity to explore different assumptions in the calculation of large-scale carbon budgets. Simulations of TCS with our empirical model were used to test three assumptions often made in carbon budgets: 1) the use of carbon accumulation in tree aboveground biomass as a surrogate for accumulation of TCS, 2) the implicit consideration of carbon legacies from previous land-use, and 3) the omission of landscape age in calculating accumulation rates of TCS. Our simulations showed that in many situations carbon can be released from regrowing secondary forests depending on the amount of carbon legacies and the average age of the landscape. In most cases, the rates used to predict carbon accumulation in the Americas were above the rates predicted in our simulations. These biome level rates seemed to be realistic only in landscapes not affected by carbon legacies from previous land-use and mean ages of around 10 years.

  4. Total carbon accumulation in a tropical forest landscape

    PubMed Central

    2012-01-01

    Background Regrowing tropical forests worldwide sequester important amounts of carbon and restore part of the C emissions emitted by deforestation. However, there are large uncertainties concerning the rates of carbon accumulation after the abandonment of agricultural and pasture land. We report here accumulation of total carbon stocks (TCS) in a chronosequence of secondary forests at a mid-elevation landscape (900-1200 m asl) in the Andean mountains of Colombia. Results We found positive accumulation rates for all ecosystem pools except soil carbon, which showed no significant trend of recovery after 36 years of secondary succession. We used these data to develop a simple model to predict accumulation of TCS over time. This model performed remarkably well predicting TCS at other chronosequences in the Americas (Root Mean Square Error < 40 Mg C ha-1), which provided an opportunity to explore different assumptions in the calculation of large-scale carbon budgets. Simulations of TCS with our empirical model were used to test three assumptions often made in carbon budgets: 1) the use of carbon accumulation in tree aboveground biomass as a surrogate for accumulation of TCS, 2) the implicit consideration of carbon legacies from previous land-use, and 3) the omission of landscape age in calculating accumulation rates of TCS. Conclusions Our simulations showed that in many situations carbon can be released from regrowing secondary forests depending on the amount of carbon legacies and the average age of the landscape. In most cases, the rates used to predict carbon accumulation in the Americas were above the rates predicted in our simulations. These biome level rates seemed to be realistic only in landscapes not affected by carbon legacies from previous land-use and mean ages of around 10 years. PMID:23249727

  5. Coordinate alignment of combined measurement systems using a modified common points method

    NASA Astrophysics Data System (ADS)

    Zhao, G.; Zhang, P.; Xiao, W.

    2018-03-01

    The co-ordinate metrology has been extensively researched for its outstanding advantages in measurement range and accuracy. The alignment of different measurement systems is usually achieved by integrating local coordinates via common points before measurement. The alignment errors would accumulate and significantly reduce the global accuracy, thus need to be minimized. In this thesis, a modified common points method (MCPM) is proposed to combine different traceable system errors of the cooperating machines, and optimize the global accuracy by introducing mutual geometric constraints. The geometric constraints, obtained by measuring the common points in individual local coordinate systems, provide the possibility to reduce the local measuring uncertainty whereby enhance the global measuring certainty. A simulation system is developed in Matlab to analyze the feature of MCPM using the Monto-Carlo method. An exemplary setup is constructed to verify the feasibility and efficiency of the proposed method associated with laser tracker and indoor iGPS systems. Experimental results show that MCPM could significantly improve the alignment accuracy.

  6. Direct evidence for microbial-derived soil organic matter formation and its ecophysiological controls

    NASA Astrophysics Data System (ADS)

    Kallenbach, Cynthia M.; Frey, Serita D.; Grandy, A. Stuart

    2016-11-01

    Soil organic matter (SOM) and the carbon and nutrients therein drive fundamental submicron- to global-scale biogeochemical processes and influence carbon-climate feedbacks. Consensus is emerging that microbial materials are an important constituent of stable SOM, and new conceptual and quantitative SOM models are rapidly incorporating this view. However, direct evidence demonstrating that microbial residues account for the chemistry, stability and abundance of SOM is still lacking. Further, emerging models emphasize the stabilization of microbial-derived SOM by abiotic mechanisms, while the effects of microbial physiology on microbial residue production remain unclear. Here we provide the first direct evidence that soil microbes produce chemically diverse, stable SOM. We show that SOM accumulation is driven by distinct microbial communities more so than clay mineralogy, where microbial-derived SOM accumulation is greatest in soils with higher fungal abundances and more efficient microbial biomass production.

  7. Direct evidence for microbial-derived soil organic matter formation and its ecophysiological controls.

    PubMed

    Kallenbach, Cynthia M; Frey, Serita D; Grandy, A Stuart

    2016-11-28

    Soil organic matter (SOM) and the carbon and nutrients therein drive fundamental submicron- to global-scale biogeochemical processes and influence carbon-climate feedbacks. Consensus is emerging that microbial materials are an important constituent of stable SOM, and new conceptual and quantitative SOM models are rapidly incorporating this view. However, direct evidence demonstrating that microbial residues account for the chemistry, stability and abundance of SOM is still lacking. Further, emerging models emphasize the stabilization of microbial-derived SOM by abiotic mechanisms, while the effects of microbial physiology on microbial residue production remain unclear. Here we provide the first direct evidence that soil microbes produce chemically diverse, stable SOM. We show that SOM accumulation is driven by distinct microbial communities more so than clay mineralogy, where microbial-derived SOM accumulation is greatest in soils with higher fungal abundances and more efficient microbial biomass production.

  8. Suppression of glycolate oxidase causes glyoxylate accumulation that inhibits photosynthesis through deactivating Rubisco in rice.

    PubMed

    Lu, Yusheng; Li, Yong; Yang, Qiaosong; Zhang, Zhisheng; Chen, Yan; Zhang, Sheng; Peng, Xin-Xiang

    2014-03-01

    Glycolate oxidase (GLO) is a key enzyme for photorespiration in plants. Previous studies have demonstrated that suppression of GLO causes photosynthetic inhibition, and the accumulated glycolate with the deactivated Rubisco is likely involved in the regulation. Using isolated Rubisco and chloroplasts, it has been found that only glyoxylate can effectively inactivate Rubisco and meanwhile inhibit photosynthesis, but little in vivo evidence has been acquired and reported. In this study, we have generated the transgenic rice (Oryza sativa) plants with GLO being constitutively silenced, and conducted the physiological and biochemical analyses on these plants to explore the regulatory mechanism. When GLO was downregulated, the net photosynthetic rate (Pn) was reduced and the plant growth was correspondingly stunted. Surprisingly, glyoxylate, as a product of the GLO catalysis, was accumulated in response to the GLO suppression, like its substrate glycolate. Furthermore, the glyoxylate content was found to be inversely proportional to the Pn while the Pn is directly proportional to the Rubisco activation state in the GLO-suppressed plants. A mathematical fitting equation using least square method also demonstrated that the Rubisco activation state was inversely proportional to the glyoxylate content. Despite that the further analyses we have conducted failed to reveal how glyoxylate was accumulated in response to the GLO suppression, the current results do strongly suggest that there may exist an unidentified, alternative pathway to produce glyoxylate, and that the accumulated glyoxylate inhibits photosynthesis by deactivating Rubisco, and causes the photorespiratory phenotype in the GLO-suppressed rice plants. © 2013 Scandinavian Plant Physiology Society.

  9. Cigarette smoke-induced accumulation of lung dendritic cells is interleukin-1α-dependent in mice

    PubMed Central

    2012-01-01

    Background Evidence suggests that dendritic cells accumulate in the lungs of COPD patients and correlate with disease severity. We investigated the importance of IL-1R1 and its ligands IL-1α and β to dendritic cell accumulation and maturation in response to cigarette smoke exposure. Methods Mice were exposed to cigarette smoke using a whole body smoke exposure system. IL-1R1-, TLR4-, and IL-1α-deficient mice, as well as anti-IL-1α and anti-IL-1β blocking antibodies were used to study the importance of IL-1R1 and TLR4 to dendritic cell accumulation and activation. Results Acute and chronic cigarette smoke exposure led to increased frequency of lung dendritic cells. Accumulation and activation of dendritic cells was IL-1R1/IL-1α dependent, but TLR4- and IL-1β-independent. Corroborating the cellular data, expression of CCL20, a potent dendritic cells chemoattractant, was IL-1R1/IL-1α-dependent. Studies using IL-1R1 bone marrow-chimeric mice revealed the importance of IL-1R1 signaling on lung structural cells for CCL20 expression. Consistent with the importance of dendritic cells in T cell activation, we observed decreased CD4+ and CD8+ T cell activation in cigarette smoke-exposed IL-1R1-deficient mice. Conclusion Our findings convey the importance of IL-1R1/IL-1α to the recruitment and activation of dendritic cells in response to cigarette smoke exposure. PMID:22992200

  10. The Benefits of Attending Community College: A Review of the Evidence

    ERIC Educational Resources Information Center

    Belfield, Clive R.; Bailey, Thomas

    2011-01-01

    This article reviews the existing literature on the economic and other benefits of attending community college. First, the article reports on the earnings gains across all students and reviews the evidence for subgroups by gender, minority status, and credits accumulated. The article then reviews the methodological challenges associated with…

  11. Interaction and accumulation of manganese and cadmium in the manganese accumulator Lupinus albus.

    PubMed

    Zornoza, Pilar; Sánchez-Pardo, Beatriz; Carpena, Ramón O

    2010-09-01

    The effects of the interaction between Mn and Cd on the growth of the white lupin (Lupinus albus), uptake of these metals, their accumulation, and effects on heavy metal stress indicators were studied under glasshouse conditions. Plants were grown with and without Mn and/or Cd for 4 weeks. The absence of Mn and Cd led to lipid peroxidation-induced loss of flavonoids and anthocyanins in the roots, reduced the size of the plant canopy, and led to the appearance of proteoid roots. Sensitivity to Cd in white lupin was enhanced by a low Mn supply, despite lower Cd uptake and accumulation (leaf Mn:Cd concentration ratio <3), as evidenced by increased lipid peroxidation in the leaves and strong inhibition of growth. However, when the Mn supply was adequate, the plants showed few symptoms of Cd toxicity, even though Cd uptake and accumulation increased. A Mn:Cd ratio of up to 20 was enough to minimize Cd stress in the leaf, reflecting the plants' relative tolerance to Cd under such conditions. Irrespective of the Mn supply, the increase in antioxidant compounds observed in the roots of Cd-treated plants might act as a protective mechanism by minimizing the oxidative stress caused by Cd exposure. In summary, high leaf Mn concentrations seem to render white lupins more tolerant to Cd stress. Copyright 2010 Elsevier GmbH. All rights reserved.

  12. Earthquake Forecasting Through Semi-periodicity Analysis of Labeled Point Processes

    NASA Astrophysics Data System (ADS)

    Quinteros Cartaya, C. B. M.; Nava Pichardo, F. A.; Glowacka, E.; Gomez-Trevino, E.

    2015-12-01

    Large earthquakes have semi-periodic behavior as result of critically self-organized processes of stress accumulation and release in some seismogenic region. Thus, large earthquakes in a region constitute semi-periodic sequences with recurrence times varying slightly from periodicity. Nava et al., 2013 and Quinteros et al., 2013 realized that not all earthquakes in a given region need belong to the same sequence, since there can be more than one process of stress accumulation and release in it; they also proposed a method to identify semi-periodic sequences through analytic Fourier analysis. This work presents improvements on the above-mentioned method: the influence of earthquake size on the spectral analysis, and its importance in semi-periodic events identification, which means that earthquake occurrence times are treated as a labeled point process; the estimation of appropriate upper limit uncertainties to use in forecasts; and the use of Bayesian analysis to evaluate the forecast performance. This improved method is applied to specific regions: the southwestern coast of Mexico, the northeastern Japan Arc, the San Andreas Fault zone at Parkfield, and northeastern Venezuela.

  13. Disparities and menthol marketing: additional evidence in support of point of sale policies.

    PubMed

    Moreland-Russell, Sarah; Harris, Jenine; Snider, Doneisha; Walsh, Heidi; Cyr, Julianne; Barnoya, Joaquin

    2013-09-25

    This study examined factors associated with point-of-sale tobacco marketing in St. Louis, an urban city in the United States. Using spatial analysis, descriptive statistics, and multilevel modeling, we examined point-of-sale data and the proportion of mentholated cigarette and total cigarette marketing from 342 individual tobacco retail stores within St. Louis census tracts characterized by the percent of black adults and children. Menthol and total tobacco product marketing was highest in areas with the highest percentages of black residents. When examining menthol marketing to children, we did not find as strong of a relationship, however results of multilevel modeling indicate that as the proportion of black children in a census tract increased, the proportion of menthol marketing near candy also increased. These results indicate the need for communities globally to counter this targeted marketing by taking policy action specifically through the enactment of marketing restrictions provided by the 2009 Family Smoking Prevention and Tobacco Control Act and the Framework Convention of Tobacco Control.

  14. Impact of slope inclination on salt accumulation

    NASA Astrophysics Data System (ADS)

    Nachshon, Uri

    2017-04-01

    Field measurements indicated on high variability in salt accumulation along natural and cultivated slopes, even for relatively homogeneous soil conditions. It was hypothesised that slope inclination has an impact on the location of salt accumulation along the slope. A set of laboratory experiments and numerical models were used to explore the impact of slope inclination on salt accumulation. It was shown, experimentally, that for conditions of saline water source at the lower boundary of the slope - salt accumulates in low concentrations and homogeneously along the entire slope, for moderate slopes. However, as inclination increases high salt concentrations were observed at the upper parts of the slope, leaving the lower parts of the slope relatively free of salt. The traditional flow and transport models did not predict the experimental observations as they indicated also for the moderate slopes on salt accumulation in the elevated parts of the slope, away of the saline water source. Consequently - a conceptual model was raised to explain the laboratory observations. It was suggested that the interactions between slope angle, evaporation rates, hydraulic conductivity of the medium and distribution of wetness along the slope affect the saline water flow path through the medium. This lead to preferential flow path close to the soil-atmosphere interface for the steep slopes, which leads to constant wash of the salts from the evaporation front upward towards the slope upper parts, whereas for the moderate slopes, flow path is below the soil-atmosphere interface, therefore salt that accumulates at the evaporation front is not being transported upward. Understanding of salt dynamics along slopes is important for agricultural and natural environments, as well as for civil engineering purposes. Better understanding of the salt transport processes along slopes will improve our ability to minimize and to cope with soil salinization processes. The laboratory experiments and

  15. Fire effects on the Point Reyes Mountain Beaver at Point Reyes National Seashore, California

    USGS Publications Warehouse

    Fellers, Gary M.; Pratt, David; Griffin, Jennifer L.

    2004-01-01

    In October 1995, a wildlands fire burned 5,000 ha on the Point Reyes peninsula, California, USA. In most of the nonforested areas, the fire effectively cleared the ground of litter and vegetation and revealed thousands of Point Reyes mountain beaver (Aplodontia rufa phaea) burrow openings. In the first 6 months after the fire, we surveyed burned coastal scrub and riparian habitat to (1) count the number of burrow openings that existed at the time of the fire, and (2) evaluate whether signs of post-fire mountain beaver activity were evident. We estimated that only 0.4–1.7% of mountain beavers within the burn area survived the fire and immediate post-fire period. We monitored mountain beaver activity for 5 years at 8 sites where mountain beavers survived, and found little or no recovery. We estimate that the mountain beaver population will take 15–20 years post-fire to recover.

  16. Late 20th Century increase in South Pole snow accumulation

    USGS Publications Warehouse

    Mosley-Thompson, E.; Paskievitch, J.F.; Gow, A.J.; Thompson, L.G.

    1999-01-01

    A compilation of the 37-year history of net accumulation at the South Pole [Mosley-Thompson et al., 1995] suggests an increase in net annual accumulation since 1965. This record is sporadic and its quality is compromised by spatially restricted observations and nonsystematic measurement procedures. Results from a new, spatially extensive network of 236 accumulation poles document that the current 5-year (1992-1997) average annual net accumulation at the South Pole is 84.5??8.9 mm water equivalent (w.e.). This accumulation rate reflects a 30% increase since the 1960s when the best, although not optimal, records indicate that it was 65 mm w.e. Identification of two prominent beta radioactivity horizons (1954/1955 and 1964/1965) in six firn cores confirms an increase in accumulation since 1965. Viewed from a longer perspective of accumulation provided by ice cores and a snow mine study, the net accumulation of the 30-year period, 1965-1994, is the highest 30-year average of this millennium. Limited data suggest this recent accumulation increase extends beyond the South Pole region and may be characteristic of the high East Antarctic Plateau. Enhanced accumulation over the polar ice sheets has been identified as a potential early indicator of warmer sea surface temperatures and may offset a portion of the current rise in global sea level. Copyright 1999 by the American Geophysical Union.

  17. Applying ergonomics to systems: some documented "lessons learned".

    PubMed

    Hendrick, Hal W

    2008-07-01

    Based on evidence accumulated during the author's 45 years of professional experience, the author presents 23 important "lessons learned" regarding applying ergonomics to systems. Documented results from reported cases or other evidence are presented to validate each of these practical learning points.

  18. 26 CFR 1.263A-11 - Accumulated production expenditures.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 3 2011-04-01 2011-04-01 false Accumulated production expenditures. 1.263A-11... TAX (CONTINUED) INCOME TAXES (CONTINUED) Items Not Deductible § 1.263A-11 Accumulated production expenditures. (a) General rule. Accumulated production expenditures generally means the cumulative amount of...

  19. 26 CFR 1.263A-11 - Accumulated production expenditures.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 3 2013-04-01 2013-04-01 false Accumulated production expenditures. 1.263A-11... TAX (CONTINUED) INCOME TAXES (CONTINUED) Items Not Deductible § 1.263A-11 Accumulated production expenditures. (a) General rule. Accumulated production expenditures generally means the cumulative amount of...

  20. 26 CFR 1.263A-11 - Accumulated production expenditures.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 3 2014-04-01 2014-04-01 false Accumulated production expenditures. 1.263A-11... TAX (CONTINUED) INCOME TAXES (CONTINUED) Items Not Deductible § 1.263A-11 Accumulated production expenditures. (a) General rule. Accumulated production expenditures generally means the cumulative amount of...

  1. 26 CFR 1.263A-11 - Accumulated production expenditures.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 3 2012-04-01 2012-04-01 false Accumulated production expenditures. 1.263A-11... TAX (CONTINUED) INCOME TAXES (CONTINUED) Items Not Deductible § 1.263A-11 Accumulated production expenditures. (a) General rule. Accumulated production expenditures generally means the cumulative amount of...

  2. The gender gap in accrued pension rights - an indicator of women's accumulated disadvantage over the course of working life. The Hordaland Health Study (HUSK).

    PubMed

    Skogen, Jens Christoffer; Hensing, Gunnel; Øverland, Simon; Knudsen, Ann Kristin; Sivertsen, Børge; Vahtera, Jussi; Tell, Grethe S; Haukenes, Inger

    2018-05-01

    Economic gender equality is one of the goals of the Nordic Welfare states. Despite this, there is a considerable gender gap in pensionable income in the European Union, and an unmet need for measures that absorb more of the complexity associated with accumulated (dis)advantages across gender and population groups. The aims of the present study were to examine the gender difference in association between average earned pension points and 1) education and 2) current occupational prestige, and to discuss pension points as a possible indicator of accumulated disadvantages. We linked a community-based survey, the Hordaland Health study (HUSK), to the national register of insurance benefits (FD-trygd). This made it possible to trace gendered patterns of economic (dis)advantages associated with educational level, career development and gainful work over the life course for 17,275 individuals. We found profound differences in earned accrued pension rights between men and women across socioeconomic strata, and a significant interaction between pension rights and gender in the association with education and occupational prestige. Our findings indicate that men, as a group, may have lower educational attainment and occupational prestige than women, and still earn more pension points throughout their career. These differences place women at risk for future economic strain and deprivation over and above their similarly educated and positioned male counterparts. We suggest that accrued pension rights may be a relevant measure of accumulated (dis)advantages over the course of working life, and a useful indicator when gender equality is measured and discussed.

  3. Re-accumulation Scenarios Governing Final Global Shapes of Rubble-Pile Asteroids

    NASA Astrophysics Data System (ADS)

    Hestroffer, Daniel; Tanga, P.; Comito, C.; Paolicchi, P.; Walsh, K.; Richardson, D. C.; Cellino, A.

    2009-05-01

    Asteroids, since the formation of the solar system, are known to have experienced catastrophic collisions, which---depending on the impact energy---can produce a major disruption of the parent body and possibly give birth to asteroid families or binaries [1]. We present a general study of the final shape and dynamical state of asteroids produced by the re-accumulation process following a catastrophic disruption. Starting from a cloud of massive particles (mono-disperse spheres) with given density and velocity distributions, we analyse the final shape, spin state, and angular momentum of the system from numerical integration of a N-body gravitational system (code pkdgrav [2]). The re-accumulation process itself is relatively fast, with a dynamical time corresponding to the spin-period of the final body (several hours). The final global shapes---which are described as tri-axial ellipsoids---exhibit slopes consistent with a degree of shear stress sustained by interlocking particles. We point out a few results: -the final shapes are close to those of hydrostatic equilibrium for incompressible fluids, preferably Maclaurin spheroid rather than Jacobi ellipsoids -for bodies closest to the sequence of hydrostatic equilibrium, there is a direct relation between spin, density and outer shape, suggesting that the outer surface is nearly equipotential -the evolution of the shape during the process follows a track along a gradient of potential energy, without necessarily reaching its minimum -the loose random packing of the particles implies low friction angle and hence fluid-like behaviour, which extends the results of [3]. Future steps of our analysis will include feature refinements of the model initial conditions and re-accumulation process, including impact shakings, realistic velocity distributions, and non equal-sized elementary spheres. References [1] Michel P. et al. 2001. Science 294, 1696 [2] Leinhardt Z.M. et al. 2000. Icarus 146, 133 [3] Richardson D.C. et al. 2005

  4. Sodium chloride decreases cadmium accumulation and changes the response of metabolites to cadmium stress in the halophyte Carpobrotus rossii.

    PubMed

    Cheng, Miaomiao; Wang, Anan; Liu, Zhiqian; Gendall, Anthony R; Rochfort, Simone; Tang, Caixian

    2018-05-18

    Salinity affects the bioavailability of cadmium (Cd) in soils and Cd accumulation in plants, but the associated mechanisms remain unclear. This study aimed to assess the metabolic response to NaCl and Cd and the relationship between metabolites and Cd accumulation in the halophyte Carpobrotus rossii, which has potential for Cd phytoextraction. Plants were grown in nutrient solution with 0-400 mm NaCl in the presence of 5 or 15 µm Cd, with varied or constant solution Cd2+ activity. Plant growth and Cd uptake were measured, and the accumulation of peptides, and organic and amino acids in plant tissues were assessed. The addition of NaCl to Cd-containing solutions improved plant growth along with 70-87 % less shoot Cd accumulation, resulting from decreases in Cd root uptake and root-to-shoot translocation irrespective of Cd2+ activity in solutions. Moreover, Cd exposure increased the concentration of phytochelatins, which correlated positively with Cd concentrations in plants regardless of NaCl addition. In comparison, Cd inhibited the synthesis of organic acids in shoots and roots in the absence of NaCl, but increased it in shoots in the presence of NaCl. While Cd increased the concentrations of amino acids in plant shoots, the effect of NaCl on the synthesis of amino acids was inconsistent. Our data provide the first evidence that NaCl decreased Cd shoot accumulation in C. rossii by decreasing Cd root uptake and root-to-shoot translocation even under constant Cd2+ activity. The present study also supports the important role of peptides and organic acids, particular of phytochelatins, in Cd tolerance and accumulation although the changes of those metabolites was not the main reason for the decreased Cd accumulation.

  5. Experimental and numerical investigations of the geometry influence on gas accumulation using a V-shaped forest model

    NASA Astrophysics Data System (ADS)

    Coudour, Bruno; Chetehouna, Khaled; Conan, Boris; Aubrun, Sandrine; Kaiss, Ahmed; Garo, Jean-Pierre

    2016-09-01

    Accumulation of gas inside a valley exposed to crosswind is experimented in this paper to extrapolate it to a case of a forest fire approaching a thalweg. Experimentations were done inside a wind tunnel using a 1/400 forest model configured as a valley with two different internal angles. The forest was modelled by mesh cylinders so that a parallel is possible with a real forest thanks to similitude laws. Gas emission was ensured by 400 tubes introduced inside the cylinders and supplied with ethane which acted as a tracer. The 400 tubes were divided into four independent parts of 100 tubes, inside and outside the valley, to be able to study independently the influence of the different zones of the forest model on the gas accumulation. We focused on the measurements of velocity by Laser-Doppler Velocimetry (LDV) and concentration with a Flame Ionization Detector (FID) to visualise the flow and quantify the accumulation of ethane. Analysing velocity, turbulence and concentration, a stagnation point was observed in the thalweg for the flattest valley and a recirculation zone for the deepest one where gas accumulation reached up to four times the concentration measured outside the valley due to airflow. The study of the influence of the different emission zones showed that gas accumulation mainly comes from the zones inside the valley. All these data permitted us to validate a numerical modelling which will enable us to study more cases, varying above all gas density but also choosing more valley angles and configurations. Another interest of the numerical model is the possibility of adding a thermal model.

  6. Evaluating Insects as Bioindicators of Heavy Metal Contamination and Accumulation near Industrial Area of Gujrat, Pakistan

    PubMed Central

    Azam, Iqra; Afsheen, Sumera; Zia, Ahmed; Javed, Muqaddas; Saeed, Rashid; Sarwar, Muhammad Kaleem; Munir, Bushra

    2015-01-01

    To study the accumulation and contamination of heavy metals (i.e., Cd, Cr, Cu, Ni, and Zn) in soil, air, and water, few insect species were assayed as ecological indicators. Study area comes under industrial zone of district Gujrat of Punjab, Pakistan. Insects used as bioindicators included a libellulid dragonfly (Crocothemis servilia), an acridid grasshopper (Oxya hyla hyla), and a nymphalid butterfly (Danaus chrysippus) near industrial zone of Gujrat. Accumulation of Cd was highest in insect species followed by Cu, Cr, Zn, and Ni at p < 0.05. Hierarchical cluster analysis (HACA) was carried out to study metal accumulation level in all insects. Correlation and regression analysis confirmed HACA observations and declared concentration of heavy metals above permissible limits. Metal concentrations in insects were significantly higher near industries and nallahs in Gujrat and relatively higher concentrations of metals were found in Orthoptera than Odonata and Lepidoptera. The total metal concentrations in insects were pointed significantly higher at sites S3 (Mid of HalsiNala), S9 (End of HalsiNala), and S1 (Start of HalsiNala), whereas lowest value was detected at site S6 (Kalra Khasa) located far from industrial area. HACA indicates that these insect groups are potential indicators of metal contamination and can be used in biomonitoring. PMID:26167507

  7. Evaluating Insects as Bioindicators of Heavy Metal Contamination and Accumulation near Industrial Area of Gujrat, Pakistan.

    PubMed

    Azam, Iqra; Afsheen, Sumera; Zia, Ahmed; Javed, Muqaddas; Saeed, Rashid; Sarwar, Muhammad Kaleem; Munir, Bushra

    2015-01-01

    To study the accumulation and contamination of heavy metals (i.e., Cd, Cr, Cu, Ni, and Zn) in soil, air, and water, few insect species were assayed as ecological indicators. Study area comes under industrial zone of district Gujrat of Punjab, Pakistan. Insects used as bioindicators included a libellulid dragonfly (Crocothemis servilia), an acridid grasshopper (Oxya hyla hyla), and a nymphalid butterfly (Danaus chrysippus) near industrial zone of Gujrat. Accumulation of Cd was highest in insect species followed by Cu, Cr, Zn, and Ni at p < 0.05. Hierarchical cluster analysis (HACA) was carried out to study metal accumulation level in all insects. Correlation and regression analysis confirmed HACA observations and declared concentration of heavy metals above permissible limits. Metal concentrations in insects were significantly higher near industries and nallahs in Gujrat and relatively higher concentrations of metals were found in Orthoptera than Odonata and Lepidoptera. The total metal concentrations in insects were pointed significantly higher at sites S3 (Mid of HalsiNala), S9 (End of HalsiNala), and S1 (Start of HalsiNala), whereas lowest value was detected at site S6 (Kalra Khasa) located far from industrial area. HACA indicates that these insect groups are potential indicators of metal contamination and can be used in biomonitoring.

  8. Highly anomalous accumulation rates of C and N recorded by a relic, free-floating peatland in Central Italy

    PubMed Central

    Zaccone, Claudio; Lobianco, Daniela; Shotyk, William; Ciavatta, Claudio; Appleby, Peter G.; Brugiapaglia, Elisabetta; Casella, Laura; Miano, Teodoro M.; D’Orazio, Valeria

    2017-01-01

    Floating islands mysteriously moving around on lakes were described by several Latin authors almost two millennia ago. These fascinating ecosystems, known as free-floating mires, have been extensively investigated from ecological, hydrological and management points of view, but there have been no detailed studies of their rates of accumulation of organic matter (OM), organic carbon (OC) and total nitrogen (TN). We have collected a peat core 4 m long from the free-floating island of Posta Fibreno, a relic mire in Central Italy. This is the thickest accumulation of peat ever found in a free-floating mire, yet it has formed during the past seven centuries and represents the greatest accumulation rates, at both decadal and centennial timescale, of OM (0.63 vs. 0.37 kg/m2/yr), OC (0.28 vs. 0.18 kg/m2/yr) and TN (3.7 vs. 6.1 g/m2/yr) ever reported for coeval peatlands. The anomalously high accretion rates, obtained using 14C age dating, were confirmed using 210Pb and 137Cs: these show that the top 2 m of Sphagnum-peat has accumulated in only ~100 years. As an environmental archive, Posta Fibreno offers a temporal resolution which is 10x greater than any terrestrial peat bog, and promises to provide new insight into environmental changes occurring during the Anthropocene. PMID:28230066

  9. Cultural evolutionary tipping points in the storage and transmission of information.

    PubMed

    Bentley, R Alexander; O'Brien, Michael J

    2012-01-01

    Human culture has evolved through a series of major tipping points in information storage and communication. The first was the appearance of language, which enabled communication between brains and allowed humans to specialize in what they do and to participate in complex mating games. The second was information storage outside the brain, most obviously expressed in the "Upper Paleolithic Revolution" - the sudden proliferation of cave art, personal adornment, and ritual in Europe some 35,000-45,000 years ago. More recently, this storage has taken the form of writing, mass media, and now the Internet, which is arguably overwhelming humans' ability to discern relevant information. The third tipping point was the appearance of technology capable of accumulating and manipulating vast amounts of information outside humans, thus removing them as bottlenecks to a seemingly self-perpetuating process of knowledge explosion. Important components of any discussion of cultural evolutionary tipping points are tempo and mode, given that the rate of change, as well as the kind of change, in information storage and transmission has not been constant over the previous million years.

  10. Stability of the accumulation pattern around Dome C over the last glacial cycle

    NASA Astrophysics Data System (ADS)

    Cavitte, Marie; Parrenin, Frédéric; Ritz, Catherine; Blankenship, Donald; Young, Duncan; Frezzotti, Massimo; Roberts, Jason; van Ommen, Tas

    2017-04-01

    between each pair of isochrones by fitting the isochrone geometries exactly. Each "layer" therefore provides a map of the paleo-accumulation rate pattern for the time interval represented by the layer. We observe that the large-scale pattern of paleo-accumulation through the last 127 kyr has been consistent with today's: higher rates of accumulation to the NW of Dome C (i.e. nearer the coast) and lower rates with distance from the coast towards the SE. On smaller scales, we observe local accumulation highs, which correlate with local ice surface slope anomalies (usually reduced slopes) and remain stationary through time. We suggest that the stationary character of the paleo accumulation patterns, both regionally and locally, point to a relative stability of the ice sheet's surface geometry all the way back to the penultimate interglacial. This would imply a stable dome position throughout, and perhaps a balanced grounding line influence from the Byrd and Totten catchments.

  11. [Nitrate accumulating capability of some market garden vegetables].

    PubMed

    Blanc, D

    1976-01-01

    Nitrate accumulation in plant is essentially function of the amount of nitrate nitrogen present in the substrate. That can be provided by mineral fertilizers or by organic manure. Due to the amount of nitrogen fertilizers needed in order to obtain sufficient yields the presence of nitrate is a general phenomenon in vegetable. Nevertheless the distribution of nitrate ions in the different parts of the plant influences the importance of the accumulation in the different kinds of vegetable. The experiments reported showed that leaves contain more nitrate ions than roots and roots more than fruit. The results obtained in soilless culture on lettuces, tomatoes and egg-plant demonstrated that the amount of accumulated nitrate is also dependent on the equilibrium between the different ions in the nutrient solution. Ammonium, potassium, sulfate and molybdenum have been shown to influence the rate of nitrate accumulation in the different species. It appears that it is not possible to obtain vegetable without nitrate, but it is possible, by an equilibrated fertilization, to reduce the amount accumulated in the tissue.

  12. Mechanisms of intrahepatic triglyceride accumulation

    PubMed Central

    Ress, Claudia; Kaser, Susanne

    2016-01-01

    Hepatic steatosis defined as lipid accumulation in hepatocytes is very frequently found in adults and obese adolescents in the Western World. Etiologically, obesity and associated insulin resistance or excess alcohol intake are the most frequent causes of hepatic steatosis. However, steatosis also often occurs with chronic hepatitis C virus (HCV) infection and is also found in rare but potentially life-threatening liver diseases of pregnancy. Clinical significance and outcome of hepatic triglyceride accumulation are highly dependent on etiology and histological pattern of steatosis. This review summarizes current concepts of pathophysiology of common causes of hepatic steatosis, including non-alcoholic fatty liver disease (NAFLD), alcoholic fatty liver disease, chronic HCV infections, drug-induced forms of hepatic steatosis, and acute fatty liver of pregnancy. Regarding the pathophysiology of NAFLD, this work focuses on the close correlation between insulin resistance and hepatic triglyceride accumulation, highlighting the potential harmful effects of systemic insulin resistance on hepatic metabolism of fatty acids on the one side and the role of lipid intermediates on insulin signalling on the other side. Current studies on lipid droplet morphogenesis have identified novel candidate proteins and enzymes in NAFLD. PMID:26819531

  13. Divergent Evolutionary Pattern of Sugar Transporter Genes is Associated with the Difference in Sugar Accumulation between Grasses and Eudicots

    PubMed Central

    Wang, Wei; Zhou, Hui; Ma, Baiquan; Owiti, Albert; Korban, Schuyler S.; Han, Yuepeng

    2016-01-01

    Sugars play a variety of roles in plants, and their accumulation in seeds and/or surrounding pericarp tissues is distinctly different between grasses and eudicots. However, little is known about the evolutionary pattern of genes involved in sugar accumulation in these two major groups of flowering plants. Here, we compared evolutionary rates, gene duplication, and selective patterns of genes involved in sugar metabolism and transport between grasses and eudicots using six grass species and seven eudicot species as materials. Overall, sugar transporter genes exhibit divergent evolutionary patterns, whereas, sugar metabolism genes showing similar evolutionary pattern between monocots and eudicots. Sugar transporter genes have higher frequencies of recent duplication in eudicots than in grasses and their patterns of evolutionary rate are different. Evidence for divergent selection of these two groups of flowering plants is also observed in sugar transporter genes, wherein, these genes have undergone positive selection in eudicots, but not in grasses. Taken together, these findings suggest that sugar transporter genes rather than sugar metabolism genes play important roles in sugar accumulation in plants, and that divergent evolutionary patterns of sugar transporter genes are associated with the difference of sugar accumulation in storage tissues of grasses and eudicots. PMID:27356489

  14. Nutrient accumulation in planted red and jack pine.

    Treesearch

    David H. Alban

    1988-01-01

    Compares nutrient accumulation in adjacent plantations of red and jack pine in the upper Great Lakes. Describes equations developed to predict biomass and nutrient accumulation based on stand basal area and height.

  15. Endogenous adenosine produced during hypoxia attenuates neutrophil accumulation: coordination by extracellular nucleotide metabolism.

    PubMed

    Eltzschig, Holger K; Thompson, Linda F; Karhausen, Jorn; Cotta, Richard J; Ibla, Juan C; Robson, Simon C; Colgan, Sean P

    2004-12-15

    Hypoxia is a well-documented inflammatory stimulus and results in tissue polymorphonuclear leukocyte (PMN) accumulation. Likewise, increased tissue adenosine levels are commonly associated with hypoxia, and given the anti-inflammatory properties of adenosine, we hypothesized that adenosine production via adenine nucleotide metabolism at the vascular surface triggers an endogenous anti-inflammatory response during hypoxia. Initial in vitro studies indicated that endogenously generated adenosine, through activation of PMN adenosine A(2A) and A(2B) receptors, functions as an antiadhesive signal for PMN binding to microvascular endothelia. Intravascular nucleotides released by inflammatory cells undergo phosphohydrolysis via hypoxia-induced CD39 ectoapyrase (CD39 converts adenosine triphosphate/adenosine diphosphate [ATP/ADP] to adenosine monophosphate [AMP]) and CD73 ecto-5'-nucleotidase (CD73 converts AMP to adenosine). Extensions of our in vitro findings using cd39- and cd73-null animals revealed that extracellular adenosine produced through adenine nucleotide metabolism during hypoxia is a potent anti-inflammatory signal for PMNs in vivo. These findings identify CD39 and CD73 as critical control points for endogenous adenosine generation and implicate this pathway as an innate mechanism to attenuate excessive tissue PMN accumulation.

  16. Ethanol accumulation in drought-stressed conifer seedlings

    Treesearch

    Daniel K. Manter; Rick G. Kelsey

    2008-01-01

    In this study, we investigated the effect of drought stress on ethanol production and accumulation in tissues from seedlings of three conifers (Douglas-fir, lodgepole pine, and ponderosa pine) with increasing degrees of tolerance to drought stress. Significant ethanol accumulation was only observed in their aerial tissues when severely stressed (water potential

  17. Flavonoid accumulation patterns of transparent testa mutants of arabidopsis

    NASA Technical Reports Server (NTRS)

    Peer, W. A.; Brown, D. E.; Tague, B. W.; Muday, G. K.; Taiz, L.; Murphy, A. S.

    2001-01-01

    Flavonoids have been implicated in the regulation of auxin movements in Arabidopsis. To understand when and where flavonoids may be acting to control auxin movement, the flavonoid accumulation pattern was examined in young seedlings and mature tissues of wild-type Arabidopsis. Using a variety of biochemical and visualization techniques, flavonoid accumulation in mature plants was localized in cauline leaves, pollen, stigmata, and floral primordia, and in the stems of young, actively growing inflorescences. In young Landsberg erecta seedlings, aglycone flavonols accumulated developmentally in three regions, the cotyledonary node, the hypocotyl-root transition zone, and the root tip. Aglycone flavonols accumulated at the hypocotyl-root transition zone in a developmental and tissue-specific manner with kaempferol in the epidermis and quercetin in the cortex. Quercetin localized subcellularly in the nuclear region, plasma membrane, and endomembrane system, whereas kaempferol localized in the nuclear region and plasma membrane. The flavonoid accumulation pattern was also examined in transparent testa mutants blocked at different steps in the flavonoid biosynthesis pathway. The transparent testa mutants were shown to have precursor accumulation patterns similar to those of end product flavonoids in wild-type Landsberg erecta, suggesting that synthesis and end product accumulation occur in the same cells.

  18. Selenium accumulation in plants--phytotechnological applications and ecological implications.

    PubMed

    Valdez Barillas, José Rodolfo; Quinn, Colin F; Pilon-Smits, Elizabeth A H

    2011-01-01

    Selenium (Se) is an essential trace element for many organisms including humans, yet toxic at higher levels. Both Se deficiency and toxicity are problems worldwide. Since plants readily accumulate and volatilize Se, they may be used both as a source of dietary Se and for removing excess Se from the environment. Plant species differ in their capacity to metabolize and accumulate Se, from non-Se accumulators (< 100 mg Se/kg DW), to Se-accumulators (100-1000 mg Se/kg DW) to Se hyperaccumulators (> 1,000 mg Se/kg DW). Here we review plant mechanisms of Se metabolism in these various plant types. We also summarize results from genetic engineering that have led to enhanced plant Se accumulation, volatilization, and/or tolerance, including field studies. Before using Se-accumulating plants at a large scale we need to evaluate the ecological implications. Research so far indicates that plant Se accumulation significantly affects the plant's ecological interactions below and above ground. Selenium canprotect plants from fungal pathogens and from a variety of invertebrate and vertebrate herbivores, due to both deterrence and toxicity. However, specialist (Se-tolerant herbivores), detritivores and endophytes appear to utilize Se hyperaccumulator plants as a resource. These findings are relevant for managing phytoremediation of Se and similar elements.

  19. The Role of Interest in Physical Education: A Review of Research Evidence

    ERIC Educational Resources Information Center

    Chen, Ang; Wang, Yubing

    2017-01-01

    This article focuses on the research on interest, especially situational interest, in physical education. Interest has been considered a powerful motivator for children and adolescents. Based on a conceptualization of individual and situational interest, a reasonable size of evidence has been accumulated showing that situational interest motivates…

  20. Ionic charge accumulation at microscopic interfaces in filled composites

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

    Zhu Yutao; Wang Xinheng; Xie Hengkun

    1996-12-31

    In this paper the charge accumulation process at microscopic interfaces in insulating materials filled with inorganic fillers is analyzed by using a unit model. Dynamic equations of interfacial ionic charge accumulation are proposed by the authors. The charge accumulation and its regulations are proved by TSC test results obtained on silica filled EPDM samples.

  1. Clicking for Grades? Really? Investigating the Use of Clickers for Awarding Grade-Points in Post-Secondary Education

    ERIC Educational Resources Information Center

    White, Peter; Syncox, David; Alters, Brian

    2011-01-01

    Using classroom response systems (clickers) to accumulate grade-points has become a controversial practice as response systems have become more widely used in the last decade. Although some instructors opt to use clickers on a non-grades basis, it has become quite common to reward students for (a) correct answers, (b) participating in clicker…

  2. Accumulation by fish of contaminants released from dredged sediments

    USGS Publications Warehouse

    Seelye, James G.; Hesselberg, Robert J.; Mac, Michael J.

    1982-01-01

    Inasmuch as the process of dredging and disposing of dredged materials causes a resuspension of these materials and an increase in bioavailability of associated contaminants, we conducted a series of experiments to examine the potential accumulation by fish of contaminants from suspended sediments. In the first experiment we compared accumulation of contaminants by yellow perch of hatchery and lake origin and found that after 10 days of exposure to nonaerated sediments, fish of hatchery origin accumulated PCBs and Fe, while fish of lake origin accumulated As, Cr, Fe, and Na. Two additional exposures were conducted to evaluate the effects of aerating the sediments prior to measuring bioavailability of associated contaminants. Fish of hatchery origin exposed to nonaerated sediments for 10 days accumulated PCBs and Hg, while fish of hatchery origin exposed to aerated sediments for 10 days accumulated PCBs, DDE, Zn, Fe, Cs, and Se. These results demonstrated not only the potential for uptake of contaminants by fish as a result of dredging but also the potential utility of fish bioassays in evaluating proposed dredging operations.

  3. Disparities and Menthol Marketing: Additional Evidence in Support of Point of Sale Policies

    PubMed Central

    Moreland-Russell, Sarah; Harris, Jenine; Snider, Doneisha; Walsh, Heidi; Cyr, Julianne; Barnoya, Joaquin

    2013-01-01

    This study examined factors associated with point-of-sale tobacco marketing in St. Louis, an urban city in the United States. Using spatial analysis, descriptive statistics, and multilevel modeling, we examined point-of-sale data and the proportion of mentholated cigarette and total cigarette marketing from 342 individual tobacco retail stores within St. Louis census tracts characterized by the percent of black adults and children. Menthol and total tobacco product marketing was highest in areas with the highest percentages of black residents. When examining menthol marketing to children, we did not find as strong of a relationship, however results of multilevel modeling indicate that as the proportion of black children in a census tract increased, the proportion of menthol marketing near candy also increased. These results indicate the need for communities globally to counter this targeted marketing by taking policy action specifically through the enactment of marketing restrictions provided by the 2009 Family Smoking Prevention and Tobacco Control Act and the Framework Convention of Tobacco Control. PMID:24071922

  4. Organic carbon accumulation in Brazilian mangal sediments

    NASA Astrophysics Data System (ADS)

    Sanders, Christian J.; Smoak, Joseph M.; Sanders, Luciana M.; Sathy Naidu, A.; Patchineelam, Sambasiva R.

    2010-12-01

    This study reviews the organic carbon (OC) accumulation rates in mangrove forests, margins and intertidal mudflats in geographically distinct areas along the Brazilian coastline (Northeastern to Southern). Our initial results indicate that the mangrove forests in the Northeastern region of Brazil are accumulating more OC (353 g/m 2/y) than in the Southeastern areas (192 g/m 2/y) being that the sediment accumulation rates, 2.8 and 2.5 mm/y, and OC content ˜7.1% and ˜5.8% (dry sediment weight) were contributing factors to the discrepancies between the forests. The intertidal mudflats on the other hand showed substantially greater OC accumulation rates, sedimentation rates and content 1129 g/m 2/y and 234 g/m 2/y; 7.3 and 3.4 mm/y; 10.3% and ˜2.7% (OC of dry sediment weight content), respectively, in the Northeastern compared to the Southeastern region. Mangrove forests in the South-Southeastern regions of Brazil may be more susceptible to the rising sea level, as they are geographically constricted by the vast mountain ranges along the coastline.

  5. The limits of evidence: evidence based policy and the removal of gamete donor anonymity in the UK.

    PubMed

    Frith, Lucy

    2015-03-01

    This paper will critically examine the use of evidence in creating policy in the area of reproductive technologies. The use of evidence in health care and policy is not a new phenomenon. However, codified strategies for evidence appraisal in health care technology assessments and attempts to create evidence based policy initiatives suggest that the way evidence is used in practice and policy has changed. This paper will examine this trend by considering what is counted as 'good' evidence, difficulties in translating evidence into policy and practice and how evidence interacts with principles. To illustrate these points the removal of gamete donor anonymity in the UK in 2005 and the debates that preceded this change in the law will be examined. It will be argued that evidence will only ever take us so far and attention should also be paid to the underlying principles that guide policy. The paper will conclude with suggestions for how underlying principles can be more rigorously used in policy formation.

  6. SEARCHES FOR POINT-LIKE AND EXTENDED NEUTRINO SOURCES CLOSE TO THE GALACTIC CENTER USING THE ANTARES NEUTRINO TELESCOPE

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

    Adrián-Martínez, S.; Ardid, M.; Bou-Cabo, M.

    2014-05-01

    A search for cosmic neutrino sources using six years of data collected by the ANTARES neutrino telescope has been performed. Clusters of muon neutrinos over the expected atmospheric background have been looked for. No clear signal has been found. The most signal-like accumulation of events is located at equatorial coordinates R.A. = –46.°8 and decl. = –64.°9 and corresponds to a 2.2σ background fluctuation. In addition, upper limits on the flux normalization of an E {sup –2} muon neutrino energy spectrum have been set for 50 pre-selected astrophysical objects. Finally, motivated by an accumulation of seven events relatively close tomore » the Galactic Center in the recently reported neutrino sample of the IceCube telescope, a search for point sources in a broad region around this accumulation has been carried out. No indication of a neutrino signal has been found in the ANTARES data and upper limits on the flux normalization of an E {sup –2} energy spectrum of neutrinos from point sources in that region have been set. The 90% confidence level upper limits on the muon neutrino flux normalization vary between 3.5 and 5.1 × 10{sup –8} GeV cm{sup –2} s{sup –1}, depending on the exact location of the source.« less

  7. Genetic variation of the weaning weight of beef cattle as a function of accumulated heat stress.

    PubMed

    Santana, M L; Bignardi, A B; Eler, J P; Ferraz, J B S

    2016-04-01

    The objective of this study was to identify the genetic variation in the weaning weight (WW) of beef cattle as a function of heat stress. The WWs were recorded at approximately 205 days of age in three Brazilian beef cattle populations: Nelore (93,616), Brangus (18,906) and Tropical Composite (62,679). In view of the cumulative nature of WW, the effect of heat stress was considered as the accumulation of temperature and humidity index units (ACTHI) from the animal's birth to weaning. A reaction norm model was used to estimate the (co)variance components of WW across the ACTHI scale. The accumulation of THI units from birth to weaning negatively affected the WW. The definition of accumulated THI units as an environmental descriptor permitted to identify important genetic variation in the WW as a function of heat stress. As evidence of genotype by environment interaction, substantial heterogeneity was observed in the (co)variance components for WW across the environmental gradient. In this respect, the best animals in less stressful environments are not necessarily the best animals in more stressful environments. Furthermore, the response to selection for WW is expected to be lower in more stressful environments. © 2015 Blackwell Verlag GmbH.

  8. Direct evidence for microbial-derived soil organic matter formation and its ecophysiological controls

    DOE PAGES

    Kallenbach, Cynthia M.; Frey, Serita D.; Grandy, A. Stuart

    2016-11-28

    Soil organic matter (SOM) and the carbon and nutrients therein drive fundamental submicron- to global-scale biogeochemical processes and influence carbon-climate feedbacks. Consensus is emerging that microbial materials are an important constituent of stable SOM, and new conceptual and quantitative SOM models are rapidly incorporating this view. However, direct evidence demonstrating that microbial residues account for the chemistry, stability and abundance of SOM is still lacking. Further, emerging models emphasize the stabilization of microbial-derived SOM by abiotic mechanisms, while the effects of microbial physiology on microbial residue production remain unclear. Here we provide the first direct evidence that soil microbes producemore » chemically diverse, stable SOM. As a result, we show that SOM accumulation is driven by distinct microbial communities more so than clay mineralogy, where microbial-derived SOM accumulation is greatest in soils with higher fungal abundances and more efficient microbial biomass production.« less

  9. Direct evidence for microbial-derived soil organic matter formation and its ecophysiological controls

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

    Kallenbach, Cynthia M.; Frey, Serita D.; Grandy, A. Stuart

    Soil organic matter (SOM) and the carbon and nutrients therein drive fundamental submicron- to global-scale biogeochemical processes and influence carbon-climate feedbacks. Consensus is emerging that microbial materials are an important constituent of stable SOM, and new conceptual and quantitative SOM models are rapidly incorporating this view. However, direct evidence demonstrating that microbial residues account for the chemistry, stability and abundance of SOM is still lacking. Further, emerging models emphasize the stabilization of microbial-derived SOM by abiotic mechanisms, while the effects of microbial physiology on microbial residue production remain unclear. Here we provide the first direct evidence that soil microbes producemore » chemically diverse, stable SOM. As a result, we show that SOM accumulation is driven by distinct microbial communities more so than clay mineralogy, where microbial-derived SOM accumulation is greatest in soils with higher fungal abundances and more efficient microbial biomass production.« less

  10. Testing multi-alternative decision models with non-stationary evidence.

    PubMed

    Tsetsos, Konstantinos; Usher, Marius; McClelland, James L

    2011-01-01

    Recent research has investigated the process of integrating perceptual evidence toward a decision, converging on a number of sequential sampling choice models, such as variants of race and diffusion models and the non-linear leaky competing accumulator (LCA) model. Here we study extensions of these models to multi-alternative choice, considering how well they can account for data from a psychophysical experiment in which the evidence supporting each of the alternatives changes dynamically during the trial, in a way that creates temporal correlations. We find that participants exhibit a tendency to choose an alternative whose evidence profile is temporally anti-correlated with (or dissimilar from) that of other alternatives. This advantage of the anti-correlated alternative is well accounted for in the LCA, and provides constraints that challenge several other models of multi-alternative choice.

  11. Evidence-Based Point-of-Care Diagnostics: Current Status and Emerging Technologies

    NASA Astrophysics Data System (ADS)

    Chan, Cangel Pui Yee; Mak, Wing Cheung; Cheung, Kwan Yee; Sin, King Keung; Yu, Cheuk Man; Rainer, Timothy H.; Renneberg, Reinhard

    2013-06-01

    Point-of-care (POC) diagnostics brings tests nearer to the site of patient care. The turnaround time is short, and minimal manual interference enables quick clinical management decisions. Growth in POC diagnostics is being continuously fueled by the global burden of cardiovascular and infectious diseases. Early diagnosis and rapid initiation of treatment are crucial in the management of such patients. This review provides the rationale for the use of POC tests in acute coronary syndrome, heart failure, human immunodeficiency virus, and tuberculosis. We also consider emerging technologies that are based on advanced nanomaterials and microfluidics, improved assay sensitivity, miniaturization in device design, reduced costs, and high-throughput multiplex detection, all of which may shape the future development of POC diagnostics.

  12. Anthropogenic N deposition increases soil organic matter accumulation without altering its biochemical composition.

    PubMed

    Zak, Donald R; Freedman, Zachary B; Upchurch, Rima A; Steffens, Markus; Kögel-Knabner, Ingrid

    2017-02-01

    Accumulating evidence indicates that future rates of atmospheric N deposition have the potential to increase soil C storage by reducing the decay of plant litter and soil organic matter (SOM). Although the microbial mechanism underlying this response is not well understood, a decline in decay could alter the amount, as well as biochemical composition of SOM. Here, we used size-density fractionation and solid-state 13 C-NMR spectroscopy to explore the extent to which declines in microbial decay in a long-term (ca. 20 yrs.) N deposition experiment have altered the biochemical composition of forest floor, bulk mineral soil, as well as free and occluded particulate organic matter. Significant amounts of organic matter have accumulated in occluded particulate organic matter (~20%; oPOM); however, experimental N deposition had not altered the abundance of carboxyl, aryl, alkyl, or O/N-alkyl C in forest floor, bulk mineral soil, or any soil fraction. These observations suggest that biochemically equivalent organic matter has accumulated in oPOM at a greater rate under experimental N deposition, relative to the ambient treatment. Although we do not understand the process by which experimental N deposition has fostered the occlusion of organic matter by mineral soil particles, our results highlight the importance of interactions among the products of microbial decay and the chemical and physical properties of silt and clay particles that occlude organic matter from microbial attack. Because oPOM can reside in soils for decades to centuries, organic matter accumulating under future rates of anthropogenic N deposition could remain in soil for long periods of time. If temperate forest soils in the Northern Hemisphere respond like those in our experiment, then unabated deposition of anthropogenic N from the atmosphere has the potential to foster greater soil C storage, especially in fine-texture forest soils. © 2016 John Wiley & Sons Ltd.

  13. Evidence of Asian carp spawning upstream of a key choke point in the Mississippi River

    USGS Publications Warehouse

    Larson, James H.; Knights, Brent C.; McCalla, S. Grace; Monroe, Emy; Tuttle-Lau, Maren T.; Chapman, Duane C.; George, Amy E.; Vallazza, Jon; Amberg, Jon J.

    2017-01-01

    Bighead Carp Hypophthalmichthys nobilis, Silver Carp H. molitrix, and Grass Carp Ctenopharyngodon idella(collectively termed “Asian carp”) were introduced into North America during the 1960s and 1970s and have become established in the lower Mississippi River basin. Previously published evidence for spawning of these species in the upper Mississippi River has been limited to an area just downstream of Dam 22 (near Saverton, Missouri). In 2013 and 2014, we sampled ichthyoplankton at 18 locations in the upper Mississippi River main stem from Dam 9 through Dam 19 and in four tributaries of the Mississippi River (Des Moines, Skunk, Iowa, and Wisconsin rivers). We identified eggs and larvae by using morphological techniques and then used genetic tools to confirm species identity. The spawning events we observed often included more than one species of Asian carp and in a few cases included eggs that must have been derived from more than one upstream spawning event. The upstream extent of genetically confirmed Grass Carp ichthyoplankton was the Wisconsin River, while Bighead Carp and Silver Carp ichthyoplankton were observed in Pool 16. In all these cases, ichthyoplankton likely drifted downstream for several hours prior to collection. Higher water velocities (and, to a lesser extent, higher temperatures) were associated with an increased likelihood of observing eggs or larvae, although the temperature range we encountered was mostly above 17°C. Several major spawning events were detected in 2013, but no major spawning events were observed in 2014. The area between Dam 15 and Dam 19 appears to be the upstream edge of spawning activity for both Silver Carp and Bighead Carp, suggesting that this area could be a focal point for management efforts designed to limit further upstream movement of these species..

  14. Accumulation and interaction of hypericin in low-density lipoprotein--a photophysical study.

    PubMed

    Mukherjee, Prasun; Adhikary, Ramkrishna; Halder, Mintu; Petrich, Jacob W; Miskovsky, Pavol

    2008-01-01

    The accumulation and interaction of hypericin with the biologically important macromolecule, low-density lipoprotein (LDL), is investigated using various steady-state and time-resolved fluorescence measurements. It is concluded that multiple hypericins can penetrate considerably deeply into the LDL molecule. Up to approximately 20 nonaggregated hypericin molecules can enter LDL; but upon increasing the hypericin concentration, the fluorescence lifetime of hypericin decreases drastically, suggesting most likely the self-quenching of aggregated hypericin. There is also evidence of energy transfer from tryptophans of the constituent protein, apoB-100, to hypericin in LDL. The results demonstrate the ability of LDL to solubilize hypericin (a known photosensitizer) in nonaggregated form, which has implications for the construction of drug delivery systems.

  15. Semantic Labelling of Ultra Dense Mls Point Clouds in Urban Road Corridors Based on Fusing Crf with Shape Priors

    NASA Astrophysics Data System (ADS)

    Yao, W.; Polewski, P.; Krzystek, P.

    2017-09-01

    In this paper, a labelling method for the semantic analysis of ultra-high point density MLS data (up to 4000 points/m2) in urban road corridors is developed based on combining a conditional random field (CRF) for the context-based classification of 3D point clouds with shape priors. The CRF uses a Random Forest (RF) for generating the unary potentials of nodes and a variant of the contrastsensitive Potts model for the pair-wise potentials of node edges. The foundations of the classification are various geometric features derived by means of co-variance matrices and local accumulation map of spatial coordinates based on local neighbourhoods. Meanwhile, in order to cope with the ultra-high point density, a plane-based region growing method combined with a rule-based classifier is applied to first fix semantic labels for man-made objects. Once such kind of points that usually account for majority of entire data amount are pre-labeled; the CRF classifier can be solved by optimizing the discriminative probability for nodes within a subgraph structure excluded from pre-labeled nodes. The process can be viewed as an evidence fusion step inferring a degree of belief for point labelling from different sources. The MLS data used for this study were acquired by vehicle-borne Z+F phase-based laser scanner measurement, which permits the generation of a point cloud with an ultra-high sampling rate and accuracy. The test sites are parts of Munich City which is assumed to consist of seven object classes including impervious surfaces, tree, building roof/facade, low vegetation, vehicle and pole. The competitive classification performance can be explained by the diverse factors: e.g. the above ground height highlights the vertical dimension of houses, trees even cars, but also attributed to decision-level fusion of graph-based contextual classification approach with shape priors. The use of context-based classification methods mainly contributed to smoothing of labelling by removing

  16. Microstructural and compositional contributions towards the mechanical behavior of aging human bone measured by cyclic and impact reference point indentation.

    PubMed

    Abraham, Adam C; Agarwalla, Avinesh; Yadavalli, Aditya; Liu, Jenny Y; Tang, Simon Y

    2016-06-01

    The assessment of fracture risk often relies primarily on measuring bone mineral density, thereby accounting for only a single pathology: the loss of bone mass. However, bone's ability to resist fracture is a result of its biphasic composition and hierarchical structure that imbue it with high strength and toughness. Reference point indentation (RPI) testing is designed to directly probe bone mechanical behavior at the microscale in situ, although it remains unclear which aspects of bone composition and structure influence the results at this scale. Therefore, our goal in this study was to investigate factors that contribute to bone mechanical behavior measured by cyclic reference point indentation, impact reference point indentation, and three-point bending. Twenty-eight female cadavers (ages 57-97) were subjected to cyclic and impact RPI in parallel at the unmodified tibia mid-diaphysis. After RPI, the middiaphyseal tibiae were removed, scanned using micro-CT to obtain cortical porosity (Ct.Po.) and tissue mineral density (TMD), then tested using three-point bending, and lastly assayed for the accumulation of advanced glycation end-products (AGEs). Both the indentation distance increase from cyclic RPI (IDI) and bone material strength index from impact RPI (BMSi) were significantly correlated with TMD (r=-0.390, p=0.006; r=0.430, p=0.002; respectively). Accumulation of AGEs was significantly correlated with IDI (r=0.281, p=0.046), creep indentation distance (CID, r=0.396, p=0.004), and BMSi (r=-0.613, p<0.001). There were no significant relationships between tissue TMD or AGEs accumulation with the quasi-static material properties. Toughness decreased with increasing tissue Ct.Po. (r=-0.621, p<0.001). Other three-point bending measures also correlated with tissue Ct.Po. including the bending modulus (r=-0.50, p<0.001) and ultimate stress (r=-0.56, p<0.001). The effects of Ct.Po. on indentation were less pronounced with IDI (r=0.290, p=0.043) and BMSi (r=-0.299, p

  17. Differential Accumulation of Sunflower Tetraubiquitin mRNAs during Zygotic Embryogenesis and Developmental Regulation of Their Heat-Shock Response.

    PubMed Central

    Almoguera, C.; Coca, M. A.; Jordano, J.

    1995-01-01

    We have isolated and sequenced Ha UbiS, a cDNA for a dry-seed-stored mRNA that encodes tetraubiquitin. We have observed differential accumulation of tetraubiquitin mRNAs during sunflower (Helianthus annuus L.) zygotic embryogenesis. These mRNAs were up-regulated during late embryogenesis and reached higher prevalence in the dry seed, where they were found to be associated mainly with provascular tissue. UbiS mRNA, as confirmed by Rnase A protection experiments, accumulated also in response to heat shock, but only in leaves and later during postgerminative development. These novel observations demonstrate expression during seed maturation of specific plant polyubiquitin transcripts and developmental regulation of their heat-shock response. Using ubiquitin antibodies we also detected discrete, seed-specific proteins with distinct temporal expression patterns during zygotic embryogenesis. Some of these patterns were concurrent with UbiS mRNA accumulation in seeds. The most abundant ubiquitin-reacting proteins found in mature seeds were small (16-22 kD) and acidic (isoelectric points of 6.1-7.4). Possible functional implications for UbiS expression elicited from these observations are discussed. PMID:12228401

  18. Accumulation of Inertial Sensory Information in the Perception of Whole Body Yaw Rotation.

    PubMed

    Nesti, Alessandro; de Winkel, Ksander; Bülthoff, Heinrich H

    2017-01-01

    While moving through the environment, our central nervous system accumulates sensory information over time to provide an estimate of our self-motion, allowing for completing crucial tasks such as maintaining balance. However, little is known on how the duration of the motion stimuli influences our performances in a self-motion discrimination task. Here we study the human ability to discriminate intensities of sinusoidal (0.5 Hz) self-rotations around the vertical axis (yaw) for four different stimulus durations (1, 2, 3 and 5 s) in darkness. In a typical trial, participants experienced two consecutive rotations of equal duration and different peak amplitude, and reported the one perceived as stronger. For each stimulus duration, we determined the smallest detectable change in stimulus intensity (differential threshold) for a reference velocity of 15 deg/s. Results indicate that differential thresholds decrease with stimulus duration and asymptotically converge to a constant, positive value. This suggests that the central nervous system accumulates sensory information on self-motion over time, resulting in improved discrimination performances. Observed trends in differential thresholds are consistent with predictions based on a drift diffusion model with leaky integration of sensory evidence.

  19. Does a presentation's medium affect its message? PowerPoint, Prezi, and oral presentations.

    PubMed

    Moulton, Samuel T; Türkay, Selen; Kosslyn, Stephen M

    2017-01-01

    Despite the prevalence of PowerPoint in professional and educational presentations, surprisingly little is known about how effective such presentations are. All else being equal, are PowerPoint presentations better than purely oral presentations or those that use alternative software tools? To address this question we recreated a real-world business scenario in which individuals presented to a corporate board. Participants (playing the role of the presenter) were randomly assigned to create PowerPoint, Prezi, or oral presentations, and then actually delivered the presentation live to other participants (playing the role of corporate executives). Across two experiments and on a variety of dimensions, participants evaluated PowerPoint presentations comparably to oral presentations, but evaluated Prezi presentations more favorably than both PowerPoint and oral presentations. There was some evidence that participants who viewed different types of presentations came to different conclusions about the business scenario, but no evidence that they remembered or comprehended the scenario differently. We conclude that the observed effects of presentation format are not merely the result of novelty, bias, experimenter-, or software-specific characteristics, but instead reveal a communication preference for using the panning-and-zooming animations that characterize Prezi presentations.

  20. Calcite-accumulating large sulfur bacteria of the genus Achromatium in Sippewissett Salt Marsh

    PubMed Central

    Salman, Verena; Yang, Tingting; Berben, Tom; Klein, Frieder; Angert, Esther; Teske, Andreas

    2015-01-01

    Large sulfur bacteria of the genus Achromatium are exceptional among Bacteria and Archaea as they can accumulate high amounts of internal calcite. Although known for more than 100 years, they remain uncultured, and only freshwater populations have been studied so far. Here we investigate a marine population of calcite-accumulating bacteria that is primarily found at the sediment surface of tide pools in a salt marsh, where high sulfide concentrations meet oversaturated oxygen concentrations during the day. Dynamic sulfur cycling by phototrophic sulfide-oxidizing and heterotrophic sulfate-reducing bacteria co-occurring in these sediments creates a highly sulfidic environment that we propose induces behavioral differences in the Achromatium population compared with reported migration patterns in a low-sulfide environment. Fluctuating intracellular calcium/sulfur ratios at different depths and times of day indicate a biochemical reaction of the salt marsh Achromatium to diurnal changes in sedimentary redox conditions. We correlate this calcite dynamic with new evidence regarding its formation/mobilization and suggest general implications as well as a possible biological function of calcite accumulation in large bacteria in the sediment environment that is governed by gradients. Finally, we propose a new taxonomic classification of the salt marsh Achromatium based on their adaptation to a significantly different habitat than their freshwater relatives, as indicated by their differential behavior as well as phylogenetic distance on 16S ribosomal RNA gene level. In future studies, whole-genome characterization and additional ecophysiological factors could further support the distinctive position of salt marsh Achromatium. PMID:25909974

  1. Calcite-accumulating large sulfur bacteria of the genus Achromatium in Sippewissett Salt Marsh.

    PubMed

    Salman, Verena; Yang, Tingting; Berben, Tom; Klein, Frieder; Angert, Esther; Teske, Andreas

    2015-11-01

    Large sulfur bacteria of the genus Achromatium are exceptional among Bacteria and Archaea as they can accumulate high amounts of internal calcite. Although known for more than 100 years, they remain uncultured, and only freshwater populations have been studied so far. Here we investigate a marine population of calcite-accumulating bacteria that is primarily found at the sediment surface of tide pools in a salt marsh, where high sulfide concentrations meet oversaturated oxygen concentrations during the day. Dynamic sulfur cycling by phototrophic sulfide-oxidizing and heterotrophic sulfate-reducing bacteria co-occurring in these sediments creates a highly sulfidic environment that we propose induces behavioral differences in the Achromatium population compared with reported migration patterns in a low-sulfide environment. Fluctuating intracellular calcium/sulfur ratios at different depths and times of day indicate a biochemical reaction of the salt marsh Achromatium to diurnal changes in sedimentary redox conditions. We correlate this calcite dynamic with new evidence regarding its formation/mobilization and suggest general implications as well as a possible biological function of calcite accumulation in large bacteria in the sediment environment that is governed by gradients. Finally, we propose a new taxonomic classification of the salt marsh Achromatium based on their adaptation to a significantly different habitat than their freshwater relatives, as indicated by their differential behavior as well as phylogenetic distance on 16S ribosomal RNA gene level. In future studies, whole-genome characterization and additional ecophysiological factors could further support the distinctive position of salt marsh Achromatium.

  2. Differential accumulation of hyperforin and secohyperforin in Hypericum perforatum tissue cultures.

    PubMed

    Charchoglyan, Armen; Abrahamyan, Arusyak; Fujii, Isao; Boubakir, Zakia; Gulder, Tobias A M; Kutchan, Toni M; Vardapetyan, Hrachik; Bringmann, Gerhard; Ebizuka, Yutaka; Beerhues, Ludger

    2007-11-01

    Hyperforin is a pharmacologically active constituent of Hypericum perforatum (St. John's wort). In vitro cultures of this medicinal plant were found to contain hyperforin and three related polyprenylated acylphloroglucinol derivatives. The accumulation of these compounds was coupled to shoot regeneration, with secohyperforin being the major constituent in morphogenic cultures. The structure of secohyperforin was elucidated online by LC-DAD, -MS, and -NMR. In multiple shoot cultures, the ratio of hyperforin to secohyperforin was strongly influenced by the phytohormones N6-benzylaminopurine (BAP) and naphthalene-1-acetic acid (NAA). While increasing concentrations of BAP stimulated the formation of hyperforin, increasing concentrations of NAA elevated the level of secohyperforin. No differential stimulation was observed after elicitor treatment. Hyperforin and secohyperforin are proposed to arise from a branch point in the biosynthetic pathway.

  3. Subjective Accounts of the Turning Points that Facilitate Desistance From Intimate Partner Violence.

    PubMed

    Walker, Kate; Bowen, Erica; Brown, Sarah; Sleath, Emma

    2017-03-01

    The transition from persistence to desistance in male perpetrators of intimate partner violence (IPV) is an understudied phenomenon. This article examines the factors that initiate and facilitate primary desistance from IPV. The narratives of 22 male perpetrators of IPV (13 desisters and 9 persisters), 7 female survivors, and 9 programme (IPV interventions) facilitators, in England, were analysed using thematic analysis. In their accounts, the participants described how the change from persister to desister did not happen as a result of discrete unique incidents but instead occurred through a number of catalysts or stimuli of change. These triggers were experienced gradually and accumulated over time in number and in type. In particular, Negative consequences of violence and Negative emotional responses needed to accumulate so that the Point of resolve: Autonomous decision to change was finally realised. This process facilitated and initiated the path of change and thus primary desistance from IPV.

  4. An Analysis of Strain Accumulation in the Western Part of Black Sea Region in Turkey

    NASA Astrophysics Data System (ADS)

    Deniz, I.; Avsar, N. B.; Deniz, R.; Mekik, C.; Kutoglu, S.

    2014-12-01

    Turkish National Horizontal Control Network (TNHCN) based on the European Datum 1950 (ED50) was used as the principal geodetic network until 2005 in Turkey. Since 2005, Turkish Large Scale Map and Map Information Production Regulation have required that that all the densification points have been produced within the same datum of Turkish National Fundamental GPS Network (TNFGN) put into practise in 2002 and based on International Terrestrial Reference Frame (ITRF). Hence, the common points were produced in both European Datum 1950 (ED50), and TNFGN.It is known that the geological and geophysical information about the network area can be obtained by the evaluation of the coordinate and scale variations in a geodetic network. For one such evaluation, the coordinate variations and velocities of network points, and also the strains are investigated. However, the principal problem in derivation of velocities arises from two different datums. In this context, the computation of velocities using the coordinate data of the ED50 and TNFGN is not accurate and reliable. Likewise, the analysis of strain from the coordinate differences is not reliable. However, due to the fact that the scale of a geodetic network is independent from datum, the strains can be derived from scale variations accurately and reliably.In this study, a test area limited 39.5°-42.0° northern latitudes and 31.0°-37.0° eastern longitudes was chosen. The benchmarks in this test area are composed of 30 geodetic control points derived with the aim of cadastral and engineering applications. We used data mining to investigate the common benchmarks in both reference systems for this area. Accordingly, the ED50 and TNFGN coordinates refer 1954 and 2005, respectively. Thus, it has been investigated the strain accumulation of 51 years in this region. It should be also noted that since 1954, the earthquakes have not registered greater than magnitude 6.0 in the test area. It is a considerable situation for this

  5. Metabolic Adaptation in Transplastomic Plants Massively Accumulating Recombinant Proteins

    PubMed Central

    Bally, Julia; Job, Claudette; Belghazi, Maya; Job, Dominique

    2011-01-01

    Background Recombinant chloroplasts are endowed with an astonishing capacity to accumulate foreign proteins. However, knowledge about the impact on resident proteins of such high levels of recombinant protein accumulation is lacking. Methodology/Principal Findings Here we used proteomics to characterize tobacco (Nicotiana tabacum) plastid transformants massively accumulating a p-hydroxyphenyl pyruvate dioxygenase (HPPD) or a green fluorescent protein (GFP). While under the conditions used no obvious modifications in plant phenotype could be observed, these proteins accumulated to even higher levels than ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco), the most abundant protein on the planet. This accumulation occurred at the expense of a limited number of leaf proteins including Rubisco. In particular, enzymes involved in CO2 metabolism such as nuclear-encoded plastidial Calvin cycle enzymes and mitochondrial glycine decarboxylase were found to adjust their accumulation level to these novel physiological conditions. Conclusions/Significance The results document how protein synthetic capacity is limited in plant cells. They may provide new avenues to evaluate possible bottlenecks in recombinant protein technology and to maintain plant fitness in future studies aiming at producing recombinant proteins of interest through chloroplast transformation. PMID:21966485

  6. Implications of metal accumulation mechanisms to phytoremediation.

    PubMed

    Memon, Abdul R; Schröder, Peter

    2009-03-01

    Trace elements (heavy metals and metalloids) are important environmental pollutants, and many of them are toxic even at very low concentrations. Pollution of the biosphere with trace elements has accelerated dramatically since the Industrial Revolution. Primary sources are the burning of fossil fuels, mining and smelting of metalliferous ores, municipal wastes, agrochemicals, and sewage. In addition, natural mineral deposits containing particularly large quantities of heavy metals are found in many regions. These areas often support characteristic plant species thriving in metal-enriched environments. Whereas many species avoid the uptake of heavy metals from these soils, some of them can accumulate significantly high concentrations of toxic metals, to levels which by far exceed the soil levels. The natural phenomenon of heavy metal tolerance has enhanced the interest of plant ecologists, plant physiologists, and plant biologists to investigate the physiology and genetics of metal tolerance in specialized hyperaccumulator plants such as Arabidopsis halleri and Thlaspi caerulescens. In this review, we describe recent advances in understanding the genetic and molecular basis of metal tolerance in plants with special reference to transcriptomics of heavy metal accumulator plants and the identification of functional genes implied in tolerance and detoxification. Plants are susceptible to heavy metal toxicity and respond to avoid detrimental effects in a variety of different ways. The toxic dose depends on the type of ion, ion concentration, plant species, and stage of plant growth. Tolerance to metals is based on multiple mechanisms such as cell wall binding, active transport of ions into the vacuole, and formation of complexes with organic acids or peptides. One of the most important mechanisms for metal detoxification in plants appears to be chelation of metals by low-molecular-weight proteins such as metallothioneins and peptide ligands, the phytochelatins. For

  7. Bicarbonate trigger for inducing lipid accumulation in algal systems

    DOEpatents

    Gardner, Robert; Peyton, Brent; Cooksey, Keith E.

    2015-08-04

    The present invention provides bicarbonate containing and/or bicarbonate-producing compositions and methods to induce lipid accumulation in an algae growth system, wherein the algae growth system is under light-dark cycling condition. By adding said compositions at a specific growth stage, said methods lead to much higher lipid accumulation and/or significantly reduced total time required for accumulating lipid in the algae growth system.

  8. Experimental measurement and modeling of snow accumulation and snowmelt in a mountain microcatchment

    NASA Astrophysics Data System (ADS)

    Danko, Michal; Krajčí, Pavel; Hlavčo, Jozef; Kostka, Zdeněk; Holko, Ladislav

    2016-04-01

    Fieldwork is a very useful source of data in all geosciences. This naturally applies also to the snow hydrology. Snow accumulation and snowmelt are spatially very heterogeneous especially in non-forested, mountain environments. Direct field measurements provide the most accurate information about it. Quantification and understanding of processes, that cause these spatial differences are crucial in prediction and modelling of runoff volumes in spring snowmelt period. This study presents possibilities of detailed measurement and modeling of snow cover characteristics in a mountain experimental microcatchment located in northern part of Slovakia in Western Tatra mountains. Catchment area is 0.059 km2 and mean altitude is 1500 m a.s.l. Measurement network consists of 27 snow poles, 3 small snow lysimeters, discharge measurement device and standard automatic weather station. Snow depth and snow water equivalent (SWE) were measured twice a month near the snow poles. These measurements were used to estimate spatial differences in accumulation of SWE. Snowmelt outflow was measured by small snow lysimeters. Measurements were performed in winter 2014/2015. Snow water equivalent variability was very high in such a small area. Differences between particular measuring points reached 600 mm in time of maximum SWE. The results indicated good performance of a snow lysimeter in case of snowmelt timing identification. Increase of snowmelt measured by the snow lysimeter had the same timing as increase in discharge at catchment's outlet and the same timing as the increase in air temperature above the freezing point. Measured data were afterwards used in distributed rainfall-runoff model MIKE-SHE. Several methods were used for spatial distribution of precipitation and snow water equivalent. The model was able to simulate snow water equivalent and snowmelt timing in daily step reasonably well. Simulated discharges were slightly overestimated in later spring.

  9. Synoptic controls on precipitation pathways and snow delivery to high-accumulation ice core sites in the Ross Sea region, Antarctica

    NASA Astrophysics Data System (ADS)

    Sinclair, K. E.; Bertler, N. A. N.; Trompetter, W. J.

    2010-11-01

    Dominant storm tracks to two ice core sites on the western margin of the Ross Sea, Antarctica (Skinner Saddle (SKS) and Evans Piedmont Glacier), are investigated to establish key synoptic controls on snow accumulation. This is critical in terms of understanding the seasonality, source regions, and transport pathways of precipitation delivered to these sites. In situ snow depth and meteorological observations are used to identify major accumulation events in 2007-2008, which differ considerably between sites in terms of their magnitude and seasonal distribution. While snowfall at Evans Piedmont Glacier occurs almost exclusively during summer and spring, Skinner Saddle receives precipitation year round with a lull during the months of April and May. Cluster analysis of daily back trajectories reveals that the highest-accumulation days at both sites result from fast-moving air masses, associated with synoptic-scale low-pressure systems. There is evidence that short-duration pulses of snowfall at SKS also originate from mesocyclone development over the Ross Ice Shelf and local moisture sources. Changes in the frequency and seasonal distribution of these mechanisms of precipitation delivery will have a marked impact on annual accumulation over time and will therefore need careful consideration during the interpretation of stable isotope and geochemical records from these ice cores.

  10. High accumulation of anthocyanins via the ectopic expression of AtDFR confers significant salt stress tolerance in Brassica napus L.

    PubMed

    Kim, Jihye; Lee, Won Je; Vu, Tien Thanh; Jeong, Chan Young; Hong, Suk-Whan; Lee, Hojoung

    2017-08-01

    The ectopic expression of AtDFR results in increased accumulation of anthocyanins leading to enhanced salinity and drought stress tolerance in B. napus plants. Flavonoids with antioxidant effects confer many additional benefits to plants. Evidence indicates that flavonoids, including anthocyanins, protect tissues against oxidative stress from various abiotic stressors. We determined whether increases in anthocyanins increased abiotic stress tolerance in Brassica napus, because the values of B. napus L. and its cultivation area are increasing worldwide. We overexpressed Arabidopsis dihydroflavonol-4-reductase (DFR) in B. napus. Increased DFR transcript levels for AtDFR-OX B. shoots correlated with higher anthocyanin accumulation. AtDFR-OX Brassica shoots exhibited lower reactive oxygen species (ROS) accumulation than wild-type (WT) shoots under high NaCl and mannitol concentrations. This was corroborated by 3,3-diaminobenzidine staining for ROS scavenging activity in 1,1-diphenyl-2-picryl-hydrazyl assays. Shoots of the AtDFR-OX B. napus lines grown in a high salt medium exhibited enhanced salt tolerance and higher chlorophyll content than similarly grown WT plants. Our observations suggested that the AtDFR gene can be effectively manipulated to modulate salinity and drought stress tolerance by directing to high accumulation of anthocyanins in oilseed plants.

  11. Accumulation of sediment-associated viruses in shellfish.

    PubMed Central

    Landry, E F; Vaughn, J M; Vicale, T J; Mann, R

    1983-01-01

    The present study focused on the importance of contaminated sediments in shellfish accumulation of human viruses. Epifaunal (Crassostrea virginica) and infaunal (Mercenaria mercenaria) shellfish, placed on or in cores, were exposed to either resuspended or undisturbed sediments containing bound poliovirus type 1 (LSc 2ab). Consistent bioaccumulation by oysters (four of five trials) was only noted when sediment-bound viruses occurred in the water column. Virus accumulation was observed in a single instance where sediments remained in an undisturbed state. While the incidence of bioaccumulation was higher with resuspended rather than undisturbed contaminated sediment, the actual concentration of accumulated viruses was not significantly different. The accumulation of viruses from oysters residing on uninoculated sediments. When clams were exposed to undisturbed, virus-contaminated sediments, two of five shellfish pools yielded viral isolates. Bioaccumulation of undisturbed sediments by these bivalves was considered marginal when related to the concentration of virus in contaminated sediments; they would only represent a significant threat when suspended in the water column. Arguments were advanced for water-column sampling in the region of the water-sediment interface to provide an accurate determination of the virological quality of shellfish harvesting waters. PMID:6297392

  12. Asynchronous accumulation of lettuce infectious yellows virus RNAs 1 and 2 and identification of an RNA 1 trans enhancer of RNA 2 accumulation.

    PubMed

    Yeh, H H; Tian, T; Rubio, L; Crawford, B; Falk, B W

    2000-07-01

    Time course and mutational analyses were used to examine the accumulation in protoplasts of progeny RNAs of the bipartite Crinivirus, Lettuce infectious yellow virus (LIYV; family Closteroviridae). Hybridization analyses showed that simultaneous inoculation of LIYV RNAs 1 and 2 resulted in asynchronous accumulation of progeny LIYV RNAs. LIYV RNA 1 progeny genomic and subgenomic RNAs could be detected in protoplasts as early as 12 h postinoculation (p.i.) and accumulated to high levels by 24 h p.i. The LIYV RNA 1 open reading frame 2 (ORF 2) subgenomic RNA was the most abundant of all LIYV RNAs detected. In contrast, RNA 2 progeny were not readily detected until ca. 36 h p.i. Mutational analyses showed that in-frame stop codons introduced into five of seven RNA 2 ORFs did not affect accumulation of progeny LIYV RNA 1 or RNA 2, confirming that RNA 2 does not encode proteins necessary for LIYV RNA replication. Mutational analyses also supported that LIYV RNA 1 encodes proteins necessary for replication of LIYV RNAs 1 and 2. A mutation introduced into the LIYV RNA 1 region encoding the overlapping ORF 1B and ORF 2 was lethal. However, mutations introduced into only LIYV RNA 1 ORF 2 resulted in accumulation of progeny RNA 1 near or equal to wild-type RNA 1. In contrast, the RNA 1 ORF 2 mutants did not efficiently support the trans accumulation of LIYV RNA 2. Three distinct RNA 1 ORF 2 mutants were analyzed and all exhibited a similar phenotype for progeny LIYV RNA accumulation. These data suggest that the LIYV RNA 1 ORF 2 encodes a trans enhancer for RNA 2 accumulation.

  13. Asynchronous Accumulation of Lettuce Infectious Yellows Virus RNAs 1 and 2 and Identification of an RNA 1 trans Enhancer of RNA 2 Accumulation

    PubMed Central

    Yeh, Hsin-Hung; Tian, Tongyan; Rubio, Luis; Crawford, Brett; Falk, Bryce W.

    2000-01-01

    Time course and mutational analyses were used to examine the accumulation in protoplasts of progeny RNAs of the bipartite Crinivirus, Lettuce infectious yellow virus (LIYV; family Closteroviridae). Hybridization analyses showed that simultaneous inoculation of LIYV RNAs 1 and 2 resulted in asynchronous accumulation of progeny LIYV RNAs. LIYV RNA 1 progeny genomic and subgenomic RNAs could be detected in protoplasts as early as 12 h postinoculation (p.i.) and accumulated to high levels by 24 h p.i. The LIYV RNA 1 open reading frame 2 (ORF 2) subgenomic RNA was the most abundant of all LIYV RNAs detected. In contrast, RNA 2 progeny were not readily detected until ca. 36 h p.i. Mutational analyses showed that in-frame stop codons introduced into five of seven RNA 2 ORFs did not affect accumulation of progeny LIYV RNA 1 or RNA 2, confirming that RNA 2 does not encode proteins necessary for LIYV RNA replication. Mutational analyses also supported that LIYV RNA 1 encodes proteins necessary for replication of LIYV RNAs 1 and 2. A mutation introduced into the LIYV RNA 1 region encoding the overlapping ORF 1B and ORF 2 was lethal. However, mutations introduced into only LIYV RNA 1 ORF 2 resulted in accumulation of progeny RNA 1 near or equal to wild-type RNA 1. In contrast, the RNA 1 ORF 2 mutants did not efficiently support the trans accumulation of LIYV RNA 2. Three distinct RNA 1 ORF 2 mutants were analyzed and all exhibited a similar phenotype for progeny LIYV RNA accumulation. These data suggest that the LIYV RNA 1 ORF 2 encodes a trans enhancer for RNA 2 accumulation. PMID:10846054

  14. Atmospheric mercury accumulation and washoff processes on impervious urban surfaces

    USGS Publications Warehouse

    Eckley, C.S.; Branfireun, B.; Diamond, M.; Van Metre, P.C.; Heitmuller, F.

    2008-01-01

    The deposition and transport of mercury (Hg) has been studied extensively in rural environments but is less understood in urbanized catchments, where elevated atmospheric Hg concentrations and impervious surfaces may efficiently deliver Hg to waterways in stormwater runoff. We determined the rate at which atmospheric Hg accumulates on windows, identified the importance of washoff in removing accumulated Hg, and measured atmospheric Hg concentrations to help understand the relationship between deposition and surface accumulation. The main study location was Toronto, Ontario. Similar samples were also collected from Austin, Texas for comparison of Hg accumulation between cities. Windows provided a good sampling surface because they are ubiquitous in urban environments and are easy to clean/blank allowing the assessment of contemporary Hg accumulation. Hg Accumulation rates were spatially variable ranging from 0.82 to 2.7 ng m-2 d-1 in Toronto and showed similar variability in Austin. The highest accumulation rate in Toronto was at the city center and was 5?? higher than the rural comparison site (0.58 ng m-2 d-1). The atmospheric total gaseous mercury (TGM) concentrations were less than 2?? higher between the rural and urban locations (1.7 ?? 0.3 and 2.7 ?? 1.1 ng m-3, respectively). The atmospheric particulate bound fraction (HgP), however, was more than 3?? higher between the rural and urban sites, which may have contributed to the higher urban Hg accumulation rates. Windows exposed to precipitation had 73 ?? 9% lower accumulation rates than windows sheltered from precipitation. Runoff collected from simulated rain events confirmed that most Hg accumulated on windows was easily removed and that most of the Hg in washoff was HgP. Our results indicate that the Hg flux from urban catchments will respond rapidly to changes in atmospheric concentrations due to the mobilization of the majority of the surface accumulated Hg during precipitation events. ?? 2008 Elsevier

  15. From evidence-based medicine to genomic medicine

    PubMed Central

    2007-01-01

    The concept of ‘evidence-based medicine’ dates back to mid-19th century or even earlier. It remains pivotal in planning, funding and in delivering the health care. Clinicians, public health practitioners, health commissioners/purchasers, health planners, politicians and public seek formal ‘evidence’ in approving any form of health care provision. Essentially ‘evidence-based medicine’ aims at the conscientious, explicit and judicious use of the current best evidence in making decisions about the care of individual patients. It is in fact the ‘personalised medicine’ in practice. Since the completion of the human genome project and the rapid accumulation of huge amount of data, scientists and physicians alike are excited on the prospect of ‘personalised health care’ based on individual’s genotype and phenotype. The first decade of the new millennium now witnesses the transition from ‘evidence-based medicine’ to the ‘genomic medicine’. The practice of medicine, including health promotion and prevention of disease, stands now at a wide-open road as the scientific and medical community embraces itself with the rapidly expanding and revolutionising field of genomic medicine. This article reviews the rapid transformation of modern medicine from the ‘evidence-based medicine’ to ‘genomic medicine’. PMID:18923934

  16. Annual Greenland Accumulation Rates (2009-2012) from Airborne Snow Radar

    NASA Technical Reports Server (NTRS)

    Koenig, Lora S.; Ivanoff, Alvaro; Alexander, Patrick M.; MacGregor, Joseph A.; Fettweis, Xavier; Panzer, Ben; Paden, John D.; Forster, Richard R.; Das, Indrani; McConnell, Joseph R.; hide

    2016-01-01

    Contemporary climate warming over the Arctic is accelerating mass loss from the Greenland Ice Sheet through increasing surface melt, emphasizing the need to closely monitor its surface mass balance in order to improve sea-level rise predictions. Snow accumulation is the largest component of the ice sheet's surface mass balance, but in situ observations thereof are inherently sparse and models are difficult to evaluate at large scales. Here, we quantify recent Greenland accumulation rates using ultra-wideband (2-6.5 gigahertz) airborne snow radar data collected as part of NASA's Operation IceBridge between 2009 and 2012. We use a semi-automated method to trace the observed radiostratigraphy and then derive annual net accumulation rates for 2009-2012. The uncertainty in these radar-derived accumulation rates is on average 14 percent. A comparison of the radarderived accumulation rates and contemporaneous ice cores shows that snow radar captures both the annual and longterm mean accumulation rate accurately. A comparison with outputs from a regional climate model (MAR - Modele Atmospherique Regional for Greenland and vicinity) shows that this model matches radar-derived accumulation rates in the ice sheet interior but produces higher values over southeastern Greenland. Our results demonstrate that snow radar can efficiently and accurately map patterns of snow accumulation across an ice sheet and that it is valuable for evaluating the accuracy of surface mass balance models.

  17. Evidence of quantum phase transition in real-space vacuum entanglement of higher derivative scalar quantum field theories.

    PubMed

    Kumar, S Santhosh; Shankaranarayanan, S

    2017-11-17

    In a bipartite set-up, the vacuum state of a free Bosonic scalar field is entangled in real space and satisfies the area-law- entanglement entropy scales linearly with area of the boundary between the two partitions. In this work, we show that the area law is violated in two spatial dimensional model Hamiltonian having dynamical critical exponent z = 3. The model physically corresponds to next-to-next-to-next nearest neighbour coupling terms on a lattice. The result reported here is the first of its kind of violation of area law in Bosonic systems in higher dimensions and signals the evidence of a quantum phase transition. We provide evidence for quantum phase transition both numerically and analytically using quantum Information tools like entanglement spectra, quantum fidelity, and gap in the energy spectra. We identify the cause for this transition due to the accumulation of large number of angular zero modes around the critical point which catalyses the change in the ground state wave function due to the next-to-next-to-next nearest neighbor coupling. Lastly, using Hubbard-Stratanovich transformation, we show that the effective Bosonic Hamiltonian can be obtained from an interacting fermionic theory and provide possible implications for condensed matter systems.

  18. 75 FR 7551 - Transfer of Accumulated Benefit Payments

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-22

    ... Transfer of Accumulated Benefit Payments AGENCY: Social Security Administration (SSA). ACTION: Final rule... that capacity to transfer accumulated benefit payments and interest directly to a beneficiary if we.... For information on eligibility or filing for benefits, call our national toll-free number, 1-800-772...

  19. Recent accumulation rates of an alpine glacier derived from firn cores and repeated helicopter-borne GPR

    NASA Astrophysics Data System (ADS)

    Sold, L.; Huss, M.; Eichler, A.; Schwikowski, M.; Hoelzle, M.

    2014-08-01

    The spatial representation of accumulation measurements is a major limitation for current glacier mass balance monitoring approaches. Here, we present a new method for estimating annual accumulation rates on a temperate alpine glacier based on the interpretation of internal reflection horizons (IRH) in helicopter-borne ground-penetrating radar (GPR) data. For each individual GPR measurement, the signal traveltime is combined with a simple model for firn densification and refreezing of meltwater. The model is calibrated at locations where GPR profiles intersect in two subsequent years and the densification can be tracked over time. Two 10.5 m long firn cores provide a reference for the density and chronology of firn layers. Thereby, IRH correspond to density maxima, but not exclusively to former summer glacier surfaces. From GPR profiles across the accumulation area, we obtain spatial distributions of water equivalent for at least four annual firn layers, reaching a mean density of 0.74 g cm-3. Refreezing accounts for 9% of the density increase over time and depth. The strongest limitation to our method is the dependence on layer chronology assumptions. The uncertainties inherent to the modelling approach itself are in the same order of conventional point measurements in snow pits. We show that GPR can be used to complement existing mass balance monitoring programs on temperate alpine glaciers, but also to retrospectively extend newly initiated time series.

  20. Design Analysis of the Ares 1 Pogo Accumulator

    NASA Technical Reports Server (NTRS)

    Swanson, Luke A.; Giel, Thomas V.

    2009-01-01

    Several accumulator designs and gas charge systems are considered in order to suppress POGO within the Ares I vehicle Upper Stage Liquid Ox ygen System. The thermodynamic and flow analysis completed to evaluat e candidate designs are presented and the results are used to evaluat e the ability of each concept to meet the levied suppression requirements. One annular accumulator design meets all suppression requirement s while also providing manufacturability and operability advantages. Of the two proposed charge systems to provide and maintain gas within the accumulator, a passive level control design meets the charge req uirements and maximizes reliability.

  1. The accumulation rate of meteorite falls at the earth's surface - The view from Roosevelt County, New Mexico

    NASA Technical Reports Server (NTRS)

    Zolensky, Michael E.; Wells, Gordon L.; Rendell, Helen M.

    1990-01-01

    The discovery of 154 meteorite fragments within an 11-sq km area of wind-excavated basins in Roosevelt County, New Mexico, permits a new calculation of the accumulation rate of meteorite falls at the earth's surface. Thermoluminescence dating of the coversand unit comprising the prime recovery surface suggests the maximum terrestrial age of the meteorites to be about 16.0 ka. The 68 meteorite fragments subjected to petrological analyses represent a minimum of 49 individual falls. Collection bias has largely excluded carbonaceous chondrites and achondrites, requiring the accumulation rate derived from the recovered samples to be increased by a factor of 1.25. Terrestrial weathering destroying ordinary chondrites can be modeled as a first-order decay process with an estimated half-life of 3.5 + or - 1.9 ka on the semiarid American High Plains. Having accounted for the age of the recovery surface, area of field searches, pairing of finds, collection bias and weathering half-life, an accumulation rate of 940 falls/a per 10 to the 6th sq km is calculated for falls greater than 10 g total mass. This figure exceeds the best-constrained previous estimate by more than an order of magnitude. One possible reason for this disparity may be the extraordinary length of the fall record preserved in the surficial geology of Roosevelt County. The high accumulation rate determined for the past 16 ka may point to the existence of periods when the meteorite fall rate was significantly greater than at present.

  2. Accumulation of BSA in Packed-bed Microfluidics

    NASA Astrophysics Data System (ADS)

    Summers, Samantha; Hu, Chuntian; Hartman, Ryan

    2012-11-01

    Alzheimers and Parkinsons are two diseases that are associated with protein deposition in the brain, causing loss of either cognitive or muscle functioning. Protein deposition diseases are considered progressive diseases since the continual aggregation of protein causes the patient's symptoms to slowly worsen over time. There are currently no known means of treatment for protein deposition diseases. Our goal is to understand the potential for packed-bed microfluidics to study protein accumulation. Measurement of the resistance to flow through micro-scale packed-beds is critical to understanding the process of protein accumulation. Aggregation in bulk is fundamentally different from accumulation on surfaces. Our study attempts to distinguish between either mechanism. The results from our experiments involving protein injection through a microfluidic system will be presented and discussed. Funding received by NSF REU Grant 1062611.

  3. Heat exchanger-accumulator

    DOEpatents

    Ecker, Amir L.

    1980-01-01

    What is disclosed is a heat exchanger-accumulator for vaporizing a refrigerant or the like, characterized by an upright pressure vessel having a top, bottom and side walls; an inlet conduit eccentrically and sealingly penetrating through the top; a tubular overflow chamber disposed within the vessel and sealingly connected with the bottom so as to define an annular outer volumetric chamber for receiving refrigerant; a heat transfer coil disposed in the outer volumetric chamber for vaporizing the liquid refrigerant that accumulates there; the heat transfer coil defining a passageway for circulating an externally supplied heat exchange fluid; transferring heat efficiently from the fluid; and freely allowing vaporized refrigerant to escape upwardly from the liquid refrigerant; and a refrigerant discharge conduit penetrating sealingly through the top and traversing substantially the length of the pressurized vessel downwardly and upwardly such that its inlet is near the top of the pressurized vessel so as to provide a means for transporting refrigerant vapor from the vessel. The refrigerant discharge conduit has metering orifices, or passageways, penetrating laterally through its walls near the bottom, communicating respectively interiorly and exteriorly of the overflow chamber for controllably carrying small amounts of liquid refrigerant and oil to the effluent stream of refrigerant gas.

  4. Mycobacterium tuberculosis Uses Host Triacylglycerol to Accumulate Lipid Droplets and Acquires a Dormancy-Like Phenotype in Lipid-Loaded Macrophages

    PubMed Central

    Daniel, Jaiyanth; Sirakova, Tatiana D.; Kolattukudy, Pappachan E.

    2011-01-01

    Two billion people are latently infected with Mycobacterium tuberculosis (Mtb). Mtb-infected macrophages are likely to be sequestered inside the hypoxic environments of the granuloma and differentiate into lipid-loaded macrophages that contain triacylglycerol (TAG)-filled lipid droplets which may provide a fatty acid-rich host environment for Mtb. We report here that human peripheral blood monocyte-derived macrophages and THP-1 derived macrophages incubated under hypoxia accumulate Oil Red O-staining lipid droplets containing TAG. Inside such hypoxic, lipid-loaded macrophages, nearly half the Mtb population developed phenotypic tolerance to isoniazid, lost acid-fast staining and accumulated intracellular lipid droplets. Dual-isotope labeling of macrophage TAG revealed that Mtb inside the lipid-loaded macrophages imports fatty acids derived from host TAG and incorporates them intact into Mtb TAG. The fatty acid composition of host and Mtb TAG were nearly identical suggesting that Mtb utilizes host TAG to accumulate intracellular TAG. Utilization of host TAG by Mtb for lipid droplet synthesis was confirmed when fluorescent fatty acid-labeled host TAG was utilized to accumulate fluorescent lipid droplets inside the pathogen. Deletion of the Mtb triacylglycerol synthase 1 (tgs1) gene resulted in a drastic decrease but not a complete loss in both radiolabeled and fluorescent TAG accumulation by Mtb suggesting that the TAG that accumulates within Mtb is generated mainly by the incorporation of fatty acids released from host TAG. We show direct evidence for the utilization of the fatty acids from host TAG for lipid metabolism inside Mtb. Taqman real-time PCR measurements revealed that the mycobacterial genes dosR, hspX, icl1, tgs1 and lipY were up-regulated in Mtb within hypoxic lipid loaded macrophages along with other Mtb genes known to be associated with dormancy and lipid metabolism. PMID:21731490

  5. Testing Multi-Alternative Decision Models with Non-Stationary Evidence

    PubMed Central

    Tsetsos, Konstantinos; Usher, Marius; McClelland, James L.

    2011-01-01

    Recent research has investigated the process of integrating perceptual evidence toward a decision, converging on a number of sequential sampling choice models, such as variants of race and diffusion models and the non-linear leaky competing accumulator (LCA) model. Here we study extensions of these models to multi-alternative choice, considering how well they can account for data from a psychophysical experiment in which the evidence supporting each of the alternatives changes dynamically during the trial, in a way that creates temporal correlations. We find that participants exhibit a tendency to choose an alternative whose evidence profile is temporally anti-correlated with (or dissimilar from) that of other alternatives. This advantage of the anti-correlated alternative is well accounted for in the LCA, and provides constraints that challenge several other models of multi-alternative choice. PMID:21603227

  6. HdhQ111 Mice Exhibit Tissue Specific Metabolite Profiles that Include Striatal Lipid Accumulation

    PubMed Central

    Carroll, Jeffrey B.; Deik, Amy; Fossale, Elisa; Weston, Rory M.; Guide, Jolene R.; Arjomand, Jamshid; Kwak, Seung; Clish, Clary B.; MacDonald, Marcy E.

    2015-01-01

    The HTT CAG expansion mutation causes Huntington’s Disease and is associated with a wide range of cellular consequences, including altered metabolism. The mutant allele is expressed widely, in all tissues, but the striatum and cortex are especially vulnerable to its effects. To more fully understand this tissue-specificity, early in the disease process, we asked whether the metabolic impact of the mutant CAG expanded allele in heterozygous B6.HdhQ111/+ mice would be common across tissues, or whether tissues would have tissue-specific responses and whether such changes may be affected by diet. Specifically, we cross-sectionally examined steady state metabolite concentrations from a range of tissues (plasma, brown adipose tissue, cerebellum, striatum, liver, white adipose tissue), using an established liquid chromatography-mass spectrometry pipeline, from cohorts of 8 month old mutant and wild-type littermate mice that were fed one of two different high-fat diets. The differential response to diet highlighted a proportion of metabolites in all tissues, ranging from 3% (7/219) in the striatum to 12% (25/212) in white adipose tissue. By contrast, the mutant CAG-expanded allele primarily affected brain metabolites, with 14% (30/219) of metabolites significantly altered, compared to wild-type, in striatum and 11% (25/224) in the cerebellum. In general, diet and the CAG-expanded allele both elicited metabolite changes that were predominantly tissue-specific and non-overlapping, with evidence for mutation-by-diet interaction in peripheral tissues most affected by diet. Machine-learning approaches highlighted the accumulation of diverse lipid species as the most genotype-predictive metabolite changes in the striatum. Validation experiments in cell culture demonstrated that lipid accumulation was also a defining feature of mutant HdhQ111 striatal progenitor cells. Thus, metabolite-level responses to the CAG expansion mutation in vivo were tissue specific and most evident

  7. DISTRIBUTED AND ACCUMULATED REINFORCEMENT ARRANGEMENTS: EVALUATIONS OF EFFICACY AND PREFERENCE

    PubMed Central

    DELEON, ISER G.; CHASE, JULIE A.; FRANK-CRAWFORD, MICHELLE A.; CARREAU-WEBSTER, ABBEY B.; TRIGGS, MANDY M.; BULLOCK, CHRISTOPHER E.; JENNETT, HEATHER K.

    2015-01-01

    We assessed the efficacy of, and preference for, accumulated access to reinforcers, which allows uninterrupted engagement with the reinforcers but imposes an inherent delay required to first complete the task. Experiment 1 compared rates of task completion in 4 individuals who had been diagnosed with intellectual disabilities when reinforcement was distributed (i.e., 30-s access to the reinforcer delivered immediately after each response) and accumulated (i.e., 5-min access to the reinforcer after completion of multiple consecutive responses). Accumulated reinforcement produced response rates that equaled or exceeded rates during distributed reinforcement for 3 participants. Experiment 2 used a concurrent-chains schedule to examine preferences for each arrangement. All participants preferred delayed, accumulated access when the reinforcer was an activity. Three participants also preferred accumulated access to edible reinforcers. The collective results suggest that, despite the inherent delay, accumulated reinforcement is just as effective and is often preferred by learners over distributed reinforcement. PMID:24782203

  8. Distributed and accumulated reinforcement arrangements: evaluations of efficacy and preference.

    PubMed

    DeLeon, Iser G; Chase, Julie A; Frank-Crawford, Michelle A; Carreau-Webster, Abbey B; Triggs, Mandy M; Bullock, Christopher E; Jennett, Heather K

    2014-01-01

    We assessed the efficacy of, and preference for, accumulated access to reinforcers, which allows uninterrupted engagement with the reinforcers but imposes an inherent delay required to first complete the task. Experiment 1 compared rates of task completion in 4 individuals who had been diagnosed with intellectual disabilities when reinforcement was distributed (i.e., 30-s access to the reinforcer delivered immediately after each response) and accumulated (i.e., 5-min access to the reinforcer after completion of multiple consecutive responses). Accumulated reinforcement produced response rates that equaled or exceeded rates during distributed reinforcement for 3 participants. Experiment 2 used a concurrent-chains schedule to examine preferences for each arrangement. All participants preferred delayed, accumulated access when the reinforcer was an activity. Three participants also preferred accumulated access to edible reinforcers. The collective results suggest that, despite the inherent delay, accumulated reinforcement is just as effective and is often preferred by learners over distributed reinforcement. © Society for the Experimental Analysis of Behavior.

  9. Leveraging Evidence-Based Practices: From Policy to Action

    ERIC Educational Resources Information Center

    Detrich, Ronnie; Keyworth, Randy; States, Jack

    2016-01-01

    Education is a public health issue. Poor educational outcomes are correlated with many health and social ills. To improve the quality of education, it will be necessary to take advantage of the leverage points of policy, evidence, and implementation science. The idea of evidence informing policy may be non-controversial, but a closer examination…

  10. A model of aging as accumulated damage matches observed mortality patterns and predicts the life-extending effects of prospective interventions

    PubMed Central

    Phoenix, Chris

    2007-01-01

    The relative insensitivity of lifespan to environmental factors constitutes compelling evidence that the physiological decline associated with aging derives primarily from the accumulation of intrinsic molecular and cellular side-effects of metabolism. Here we model that accumulation starting from a biologically based interpretation of the way in which those side-effects interact. We first validate this model by showing that it very accurately reproduces the distribution of ages at death seen in typical populations that are well protected from age-independent causes of death. We then exploit the mechanistic basis of this model to explore the impact on lifespans of interventions that combat aging, with an emphasis on interventions that repair (rather than merely retard) the direct molecular or cellular consequences of metabolism and thus prevent them from accumulating to pathogenic levels. Our results strengthen the case that an indefinite extension of healthy and total life expectancy can be achieved by a plausible rate of progress in the development of such therapies, once a threshold level of efficacy of those therapies has been reached. PMID:19424837

  11. Diorcinol D Exerts Fungicidal Action against Candida albicans through Cytoplasm Membrane Destruction and ROS Accumulation

    PubMed Central

    Li, Ying; Chang, Wenqiang; Zhang, Ming; Li, Xiaobin; Jiao, Yang; Lou, Hongxiang

    2015-01-01

    Candida albicans, which is the most common human fungal pathogen, causes high mortality among immunocompromised patients. Antifungal drug resistance becomes a major challenge for the management of Candida infection. Diorcinol D (DD), a diphenyl ether derivative isolated from an endolichenic fungus, exerted fungicidal action against Candida species. In this study, we investigated the possible mechanism of its antifungal activity. The change of membrane dynamics and permeability suggested that the cell membrane was disrupted by the treatment of DD. This was further supported by the evidences of intracellular glycerol accumulation, alteration of cell ultrastructure, and down-regulation of genes involved in cell membrane synthesis. In addition, the treatment of C. albicans with DD resulted in the elevation of reactive oxygen species (ROS), which caused the dysfunction of mitochondria. These altogether suggested that DD exerted its antifungal activity through cytoplasmic membrane destruction and ROS accumulation. This finding is helpful to uncover the underlying mechanisms for the diphenyl ether derivatives and provides a potential application in fighting clinical fungal infections. PMID:26047493

  12. Dynamical spin accumulation in large-spin magnetic molecules

    NASA Astrophysics Data System (ADS)

    Płomińska, Anna; Weymann, Ireneusz; Misiorny, Maciej

    2018-01-01

    The frequency-dependent transport through a nanodevice containing a large-spin magnetic molecule is studied theoretically in the Kondo regime. Specifically, the effect of magnetic anisotropy on dynamical spin accumulation is of primary interest. Such accumulation arises due to finite components of frequency-dependent conductance that are off diagonal in spin. Here, employing the Kubo formalism and the numerical renormalization group method, we demonstrate that the dynamical transport properties strongly depend on the relative orientation of spin moments in electrodes of the device, as well as on intrinsic parameters of the molecule. In particular, the effect of dynamical spin accumulation is found to be greatly affected by the type of magnetic anisotropy exhibited by the molecule, and it develops for frequencies corresponding to the Kondo temperature. For the parallel magnetic configuration of the device, the presence of dynamical spin accumulation is conditioned by the interplay of ferromagnetic-lead-induced exchange field and the Kondo correlations.

  13. The role of photorespiration during astaxanthin accumulation in Haematococcus pluvialis (Chlorophyceae).

    PubMed

    Zhang, Chunhui; Zhang, Litao; Liu, Jianguo

    2016-10-01

    Most previous studies on Haematococcus pluvialis have been focused on growth and astaxanthin accumulation. However, the relationships between photorespiration and astaxanthin accumulation have not been clarified. The purpose of this study was to examine the role of photorespiration during the process of astaxanthin accumulation in H. pluvialis. During astaxanthin accumulation, the astaxanthin content was reduced significantly when photorespiration was inhibited by its specific inhibitor, carboxymethoxylamine. The inhibition of photorespiration did not change the dry weight, chlorophyll content and OJIP transients during the incubation; however, the inhibition of photorespiration significantly decreased the photochemistry of photosystem II and total photosynthetic O2 evolution capacity. Moreover, the restriction in photorespiration was synchronized with a decrease of astaxanthin accumulation. These results suggest that the photorespiratory pathway in H. pluvialis can accelerate astaxanthin accumulation. We speculate that photorespiration can enhance astaxanthin accumulation in the following ways: (i) photorespiration directly affects the glycerate-3-phosphate (PGA) level, which is intrinsically related to the accumulation of astaxanthin in H. pluvialis; (ii) the photorespiratory pathway indirectly affects the PGA level by effecting the dark reactions of photosynthesis, which then results in the enhancement of astaxanthin accumulation in H. pluvialis. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  14. Cultural Evolutionary Tipping Points in the Storage and Transmission of Information

    PubMed Central

    Bentley, R. Alexander; O’Brien, Michael J.

    2012-01-01

    Human culture has evolved through a series of major tipping points in information storage and communication. The first was the appearance of language, which enabled communication between brains and allowed humans to specialize in what they do and to participate in complex mating games. The second was information storage outside the brain, most obviously expressed in the “Upper Paleolithic Revolution” – the sudden proliferation of cave art, personal adornment, and ritual in Europe some 35,000–45,000 years ago. More recently, this storage has taken the form of writing, mass media, and now the Internet, which is arguably overwhelming humans’ ability to discern relevant information. The third tipping point was the appearance of technology capable of accumulating and manipulating vast amounts of information outside humans, thus removing them as bottlenecks to a seemingly self-perpetuating process of knowledge explosion. Important components of any discussion of cultural evolutionary tipping points are tempo and mode, given that the rate of change, as well as the kind of change, in information storage and transmission has not been constant over the previous million years. PMID:23267338

  15. When All Signs Point to You: Lies Told in the Face of Evidence

    ERIC Educational Resources Information Center

    Evans, Angela D.; Xu, Fen; Lee, Kang

    2011-01-01

    Young children's ability to tell a strategic lie by making it consistent with the physical evidence of their transgression was investigated along with the sociocognitive correlates of such lie-telling behaviors. In Experiment 1, 247 Chinese children between 3 and 5 years of age (126 boys) were left alone in a room and asked not to lift a cup to…

  16. Glomerular disease augments kidney accumulation of synthetic anionic polymers.

    PubMed

    Liu, Gary W; Prossnitz, Alexander N; Eng, Diana G; Cheng, Yilong; Subrahmanyam, Nithya; Pippin, Jeffrey W; Lamm, Robert J; Ngambenjawong, Chayanon; Ghandehari, Hamidreza; Shankland, Stuart J; Pun, Suzie H

    2018-06-02

    Polymeric drug carriers can alter the pharmacokinetics of their drug cargoes, thereby improving drug therapeutic index and reducing side effects. Understanding and controlling polymer properties that drive tissue-specific accumulation is critical in engineering targeted drug delivery systems. For kidney disease applications, targeted drug delivery to renal cells that reside beyond the charge- and size-selective glomerular filtration barrier could have clinical potential. However, there are limited reports on polymer properties that might enhance kidney accumulation. Here, we studied the effects of molecular weight and charge on the in vivo kidney accumulation of polymers in health and disease. We synthesized a panel of well-defined polymers by atom transfer radical polymerization to answer several questions. First, the biodistribution of low molecular weight (23-27 kDa) polymers composed of various ratios of neutral:anionic monomers (1:0, 1:1, 1:4) in normal mice was determined. Then, highly anionic (1:4 monomer ratio) low molecular and high molecular weight (47 kDa) polymers were tested in both normal and experimental focal segmental glomerulosclerosis (FSGS) mice, a model that results in loss of glomerular filtration selectivity. Through these studies, we observed that kidney-specific polymer accumulation increases with anionic monomer content, but not molecular weight; experimental FSGS increases kidney accumulation of anionic polymers; and anionic polymers accumulate predominantly in proximal tubule cells, with some distribution in kidney glomeruli. These findings can be applied to the design of polymeric drug carriers to enhance or mitigate kidney accumulation. Copyright © 2018 Elsevier Ltd. All rights reserved.

  17. Herpes Simplex Virus 2 Infection Impacts Stress Granule Accumulation

    PubMed Central

    Finnen, Renée L.; Pangka, Kyle R.

    2012-01-01

    Interference with stress granule (SG) accumulation is gaining increased appreciation as a common strategy used by diverse viruses to facilitate their replication and to cope with translational arrest. Here, we examined the impact of infection by herpes simplex virus 2 (HSV-2) on SG accumulation by monitoring the localization of the SG components T cell internal antigen 1 (TIA-1), Ras-GTPase-activating SH3-domain-binding protein (G3BP), and poly(A)-binding protein (PABP). Our results indicate that SGs do not accumulate in HSV-2-infected cells and that HSV-2 can interfere with arsenite-induced SG accumulation early after infection. Surprisingly, SG accumulation was inhibited despite increased phosphorylation of eukaryotic translation initiation factor 2α (eIF2α), implying that HSV-2 encodes previously unrecognized activities designed to maintain translation initiation downstream of eIF2α. SG accumulation was not inhibited in HSV-2-infected cells treated with pateamine A, an inducer that works independently of eIF2α phosphorylation. The SGs that accumulated following pateamine A treatment of infected cells contained G3BP and PABP but were largely devoid of TIA-1. We also identified novel nuclear structures containing TIA-1 that form late in infection. These structures contain the RNA binding protein 68-kDa Src-associated in mitosis (Sam68) and were noticeably absent in infected cells treated with inhibitors of viral DNA replication, suggesting that they arise as a result of late events in the virus replicative cycle. PMID:22623775

  18. 19 CFR 10.534 - Accumulation.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Singapore Free Trade Agreement Rules of Origin § 10.534 Accumulation. (a) Originating materials of Singapore or the United States that...

  19. Effect of Various Conditions on Accumulation of Oxytetracycline in Escherichia coli

    PubMed Central

    Izaki, Kazuo; Arima, Kei

    1965-01-01

    Izaki, Kazuo (University of Tokyo, Tokyo, Japan), and Kei Arima. Effect of various conditions on accumulation of oxytetracycline in Escherichia coli. J. Bacteriol. 89:1335–1339. 1965.—Accumulation of large amounts of oxytetracycline occurred in Escherichia coli when the cells were incubated with high concentrations of oxytetracycline (100 to 400 μg/ml) in nutrient broth or in a medium containing glucose, K2HPO4, and MgSO4. In the absence of glucose or MgSO4, the accumulation was very small. The optimal pH for accumulation was about 6.5. Manganous ion could replace Mg++ in promoting the accumulation, though with decreased effectiveness. Malate and succinate were effective promoters of accumulation as well as glucose. Accumulation was inhibited at low temperatures or in the presence of metabolic inhibitors such as 2,4-dinitrophenol or sodium azide. Images PMID:14293007

  20. Pivots for pointing: visually-monitored pointing has higher arm elevations than pointing blindfolded.

    PubMed

    Wnuczko, Marta; Kennedy, John M

    2011-10-01

    Observers pointing to a target viewed directly may elevate their fingertip close to the line of sight. However, pointing blindfolded, after viewing the target, they may pivot lower, from the shoulder, aligning the arm with the target as if reaching to the target. Indeed, in Experiment 1 participants elevated their arms more in visually monitored than blindfolded pointing. In Experiment 2, pointing to a visible target they elevated a short pointer more than a long one, raising its tip to the line of sight. In Experiment 3, the Experimenter aligned the participant's arm with the target. Participants judged they were pointing below a visually monitored target. In Experiment 4, participants viewing another person pointing, eyes-open or eyes-closed, judged the target was aligned with the pointing arm. In Experiment 5, participants viewed their arm and the target via a mirror and posed their arm so that it was aligned with the target. Arm elevation was higher in pointing directly.

  1. Hematological, biochemical, and histopathological impacts of barium chloride and barium carbonate accumulation in soft tissues of male Sprague-Dawley rats.

    PubMed

    Mohammed, Amany Tharwat; Ismail, Hager Tarek H

    2017-12-01

    The present study was designed to investigate the hematotoxicity, sero-biochemical and histological changes due to the accumulation of BaCl 2 and BaCO 3 , the most important barium salts in our daily lives, in different soft tissues including the liver, kidney, heart, and spleen of adult rats after an oral exposure for 30 consecutive days, and to explain the different mechanisms by which this metal can exert these impacts. For this purpose, adult male rats were divided into three main groups of 15 animals each: group I, serving as controls, group II, receiving BaCl 2 orally in a dose of 179 mg barium/kg b.wt, and group III, receiving BaCO 3 orally in a dose of 418 mg barium/kg b.wt. for 30 consecutive days. Obviously, normocytic normochromic anemia was evident in both barium groups. Serum biochemical analysis revealed significant declines in glutathione peroxidase, catalase, superoxide dismutase, and urea with significant elevations in malondialdehyde, lactate dehydrogenase, and creatine kinase levels. Hyperphosphatemia, hypokalemia, hypocalcemia, and hypochloremia were also evident in both barium groups. Besides, residual analysis of both barium salts in different body organs revealed significantly abundant barium residues in the liver, spleen, heart, and kidney, respectively in both barium salts groups. Moreover, splenic tissue showed hemosiderosis, peritubular congestion, and necrotic glomeruli with intratubular hemorrhage. Sever subepicardial congestion with intramuscular edema was evident in the heart. In conclusion, BaCl 2 and BaCO 3 were able to deliver mortalities, antioxidant enzymes exhaustion, and a sort of normocytic normochromic anemia, as well as marked disturbances in cardiac, hepatic, and renal functions due to the accumulation of these two salts in the soft tissues. Therefore, these results demonstrate the unrecognized toxicity of those two barium salts due to their accumulation in various soft tissues of the body and so, this needs to reconsider

  2. Effects of 15% CO/sub 2/ on the accumulation of the phytoalexin phaseollin in Phaseolus vulgaris in response to mechanical injury and to infection by Colletotrichum lindemuthianum

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

    Arnold, R.M.; Rahe, J.E.

    1977-04-15

    Accumulation of phaseollin at sites of point-freezing injury on etiolated hypocotyls of Phaseolus vulgaris occurred in air but was prevented when seedlings were placed in air containing 15 percent CO/sub 2/ immediately after injury. The inhibitory effect was partially overcome when CO/sub 2/-treated seedlings were returned to air. Phaseollin accumulation in 15 percent CO/sub 2/ did occur, however, when injured seedlings were maintained in air for 3-9 h before being transferred to CO/sub 2/, indicating that the sensitivity to CO/sub 2/ lies at an early stage of the process leading to phaseollin production. In contrast, phaseollin accumulation at sites ofmore » infection of P. vulgaris by an incompatible race of Colletotrichum lindemuthianum was not inhibited by 15 percent CO/sub 2/. These results indicate that the processes leading to the accumulation of phaseollin at incompatible infection sites and at injury sites may be regulated differently.« less

  3. Strontium-90 Accumulation on Plant Foliage During Rainfall.

    PubMed

    Menzel, R G; Roberts, H; Stewart, E H; Mackenzie, A J

    1963-11-01

    Accumulation of strontium-90 in field-grown crops was measured during the spring of 1962. Each rainfall markedly increased the strontium-90 content of the crops, except when the plants were very small. Accumulation between rains was comparatively small, about equal to the expected uptake from the soil.

  4. Cut points on 0-10 numeric rating scales for symptoms included in the Edmonton Symptom Assessment Scale in cancer patients: a systematic review.

    PubMed

    Oldenmenger, Wendy H; de Raaf, Pleun J; de Klerk, Cora; van der Rijt, Carin C D

    2013-06-01

    To improve the management of cancer-related symptoms, systematic screening is necessary, often performed by using 0-10 numeric rating scales. Cut points are used to determine if scores represent clinically relevant burden. The aim of this systematic review was to explore the evidence on cut points for the symptoms of the Edmonton Symptom Assessment Scale. Relevant literature was searched in PubMed, CINAHL®, Embase, and PsycINFO®. We defined a cut point as the lower bound of the scores representing moderate or severe burden. Eighteen articles were eligible for this review. Cut points were determined using the interference with daily life, another symptom-related method, or a verbal scale. For pain, cut point 5 and, to a lesser extent, cut point 7 were found as the optimal cut points for moderate pain and severe pain, respectively. For moderate tiredness, the best cut point seemed to be cut point 4. For severe tiredness, both cut points 7 and 8 were suggested frequently. A lack of evidence exists for nausea, depression, anxiety, drowsiness, appetite, well-being, and shortness of breath. Few studies suggested a cut point below 4. For many symptoms, there is no clear evidence as to what the optimal cut points are. In daily clinical practice, a symptom score ≥4 is recommended as a trigger for a more comprehensive symptom assessment. Until there is more evidence on the optimal cut points, we should hold back using a certain cut point in quality indicators and be cautious about strongly recommending a certain cut point in guidelines. Copyright © 2013 U.S. Cancer Pain Relief Committee. Published by Elsevier Inc. All rights reserved.

  5. Dating the last Neanderthals in Central Iberia - New evidence from Abrigo del Molino, Segovia, Spain

    NASA Astrophysics Data System (ADS)

    Kehl, Martin; Álvarez-Alonso, David; de Andrés-Herrero, María; Díez-Herrero, Andrés; Klasen, Nicole; Rojo-Hernández, Julio; Weniger, Gerd-Christian

    2017-04-01

    The timing of Neanderthal disappearance in the Iberian Peninsula is a hotly debated subject in Palaeolithic archaeology. Several studies suggested a late survival in South and Central Iberia until about 32,000 year ago (ka), but were probably subject to significant age underestimation due to contamination of dating samples and/or lack of stratigraphic integrity. More recently, Late Neanderthal presence was dated to no later than 38 ka. In Central Iberia, few archaeological sites contain Mousterian levels attesting occupation by Neanderthals. The newly discovered rock shelter of Abrigo del Molino contains chronologically well-constraint Mousterian levels, which, according to radiocarbon dating on bone, place the latest Neanderthal occupation to around 42-44 ka and within Greenland interstadial 11. Accumulation of these levels took place after deposition of fluvial and slope sediments, dated to around 46 ± 3.5 ka using luminescence techniques, and probably correlating with Greenland stadial 13 including Heinrich event 5. Micromorphological evidence of banded sediment fabrics suggests frost dynamics pointing to cold climate conditions during that time in Central Spain. Abrigo del Molino thus provides a detailed and chronologically well-constrained record on Late Neanderthal presence and morphodynamic change in Central Iberia during times of millennial-scale climate changes. The site gives further evidence for an early rather than late disappearance of Neanderthals in Iberia.

  6. 19 CFR 10.458 - Accumulation.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Chile Free Trade Agreement Rules of Origin § 10.458 Accumulation. (a) Originating goods or materials of Chile or the United States...

  7. Macrodamage Accumulation Model for a Human Femur

    PubMed Central

    2017-01-01

    The objective of this study was to more fully understand the mechanical behavior of bone tissue that is important to find an alternative material to be used as an implant and to develop an accurate model to predict the fracture of the bone. Predicting and preventing bone failure is an important area in orthopaedics. In this paper, the macrodamage accumulation models in the bone tissue have been investigated. Phenomenological models for bone damage have been discussed in detail. In addition, 3D finite element model of the femur prepared from imaging data with both cortical and trabecular structures is delineated using MIMICS and ANSYS® and simulated as a composite structure. The damage accumulation occurring during cyclic loading was analyzed for fatigue scenario. We found that the damage accumulates sooner in the multiaxial than in the uniaxial loading condition for the same number of cycles, and the failure starts in the cortical bone. The damage accumulation behavior seems to follow a three-stage growth: a primary phase, a secondary phase of damage growth marked by linear damage growth, and a tertiary phase that leads to failure. Finally, the stiffness of the composite bone comprising the cortical and trabecular bone was significantly different as expected. PMID:28951659

  8. Burnout and Risk of Cardiovascular Disease: Evidence, Possible Causal Paths, and Promising Research Directions

    ERIC Educational Resources Information Center

    Melamed, Samuel; Shirom, Arie; Toker, Sharon; Berliner, Shlomo; Shapira, Itzhak

    2006-01-01

    Burnout is characterized by emotional exhaustion, physical fatigue, and cognitive weariness, resulting from prolonged exposure to work-related stress. The authors review the accumulated evidence suggesting that burnout and the related concept of vital exhaustion are associated with increased risk of cardiovascular disease and…

  9. Peat Accumulation in the Everglades (USA) during the Past 4000 Years: Rates, Drivers, and Sources of Error

    NASA Astrophysics Data System (ADS)

    Glaser, P. H.; Volin, J. C.; Givnish, T. J.; Hansen, B. C.; Stricker, C. A.

    2012-12-01

    Tropical and sub-tropical wetlands are considered to be globally important sources for greenhouse gases but their capacity to store carbon is presumably limited by warm soil temperatures and high rates of decomposition. Unfortunately, these assumptions can be difficult to test across long timescales because the chronology, cumulative mass, and completeness of a sedimentary profile are often difficult to establish. We therefore made a detailed analysis of a core from the principal drainage outlet of the Everglades of South Florida, to assess these problems and determine the factors that could govern carbon accumulation in this large sub-tropical wetland. AMS-14C dating provided direct evidence for both hard-water and open-system sources of dating errors, whereas cumulative mass varied depending upon the type of method used. Radiocarbon dates of gastropod shells, nevertheless, seemed to provide a reliable chronology for this core once the hard-water error was quantified and subtracted. Long-term accumulation rates were then calculated to be 12.1 g m-2 yr-1 for carbon, which is less than half the average rate reported for northern and tropical peatlands. Moreover, accumulation rates remained slow and relatively steady for both organic and inorganic strata, and the slow rate of sediment accretion ( 0.2 mm yr-1) tracked the correspondingly slow rise in sea level (0.35 mm yr-1 ) reported for South Florida over the past 4000 years. These results suggest that sea level and the local geologic setting may impose long-term constraints on rates of sediment and carbon accumulation in the Everglades and other wetlands

  10. Effects of meso-2,3-dimercaptosuccinic acid, potassium iodide and chlorophyll on lead accumulation in male mice.

    PubMed

    Xie, Ying; Zhou, Guifeng

    2017-02-21

    Lead (Pb) pollution is a serious public health problem all over the world, it especially plays severe damage role in children's health. Apart from reducing lead-induced damages, the decrease of lead accumulation is also critical. This study has been the first attempt to investigate effects of meso-2,3-dimercaptosuccinic acid (DMSA), potassium iodide (KI) and chlorophyll (Chl) on lead accumulation in male mice. Eighty healthy Kunming male mice were selected and divided randomly into 8 groups. They were treated with lead acetate (PbAc) intraperitoneally, individually and in combination with the DMSA, KI or Chl once daily for 5 days. Meanwhile, the control group was treated with normal saline during the whole exposure period. On 30th day, mice were sacrificed and lead concentrations were detected in the whole blood, livers, kidneys, and testicles of mice by means of the graphite furnace atomic absorption spectrometry. In comparison with the control group, lead concentrations increased in mice treated with the PbAc and DMSA, KI and Chl diminished lead accumulation in the whole blood, livers, and kidneys. Chl had specifically the same effects on lead concentrations in the testicles of male mice. Potassium iodide and Chl, as food additives, had the same effects as the DMSA to reduce lead accumulation in male mice effectively. Our results provided experimental evidence in vivo for the preventive measures of lead poisoning. Int J Occup Med Environ Health 2017;30(1):87-93. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

  11. Specific cellular accumulation of photofrin-II in EC cells promotes photodynamic treatment efficacy in esophageal cancer.

    PubMed

    Gao, Shegan; Liang, Shuo; Ding, Kaili; Qu, Zhifeng; Wang, Ying; Feng, Xiaoshan

    2016-06-01

    Photodynamic therapy (PDT), which uses a light-sensitive compound and laser irradiation, is a light-based oncological treatment modality. PDT offers an alternative, less invasive treatment for various malignant tumors, such as esophageal cancer (EC), through a photochemical reaction induced by photofrin-II or other oncotropic photosensitizers without severe complications. Previous studies has shown that cancerous tissues accumulated more photosensitizers than paired normal tissues, however, whether it is cellular or vascular mechanisms remains unknown. Herein, in vivo and in vitro examinations were performed to study the mechanisms by which photofrin-II effectively and specifically killed EC cells. In this study, EC tissue of patients treated with photofrin-II, human ESCC cellline SHEEC and parental normal cellline SHEE, primary culture cells of EC tissue were used. The concentration of photofrin-II in cells were evaluated by high-performance liquid chromatography (HPLC). The results exhibited that accumulation of photofrin-II in cancerous cells were significantly higher than that in non-cancerous cells (p<0.05) under certain dose and time period of incubation of photofrin-II. In summary, our study showed that, photofrin-II specifically accumulated in EC cells in vivo and in vitro after controlling for vascular factors, which provided strong evidence that maybe the cellular factor is the main mechanism by which photofrin-II-mediated PDT selectively caused EC cells death. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Flavonoid Accumulation Patterns of Transparent Testa Mutants of Arabidopsis1

    PubMed Central

    Peer, Wendy Ann; Brown, Dana E.; Tague, Brian W.; Muday, Gloria K.; Taiz, Lincoln; Murphy, Angus S.

    2001-01-01

    Flavonoids have been implicated in the regulation of auxin movements in Arabidopsis. To understand when and where flavonoids may be acting to control auxin movement, the flavonoid accumulation pattern was examined in young seedlings and mature tissues of wild-type Arabidopsis. Using a variety of biochemical and visualization techniques, flavonoid accumulation in mature plants was localized in cauline leaves, pollen, stigmata, and floral primordia, and in the stems of young, actively growing inflorescences. In young Landsberg erecta seedlings, aglycone flavonols accumulated developmentally in three regions, the cotyledonary node, the hypocotyl-root transition zone, and the root tip. Aglycone flavonols accumulated at the hypocotyl-root transition zone in a developmental and tissue-specific manner with kaempferol in the epidermis and quercetin in the cortex. Quercetin localized subcellularly in the nuclear region, plasma membrane, and endomembrane system, whereas kaempferol localized in the nuclear region and plasma membrane. The flavonoid accumulation pattern was also examined in transparent testa mutants blocked at different steps in the flavonoid biosynthesis pathway. The transparent testa mutants were shown to have precursor accumulation patterns similar to those of end product flavonoids in wild-type Landsberg erecta, suggesting that synthesis and end product accumulation occur in the same cells. PMID:11402185

  13. 5 CFR 630.304 - Accumulation limitation for part-time employees.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Accumulation limitation for part-time... REGULATIONS ABSENCE AND LEAVE Annual Leave § 630.304 Accumulation limitation for part-time employees. A part-time employee may accumulate not more than 240 or 360 hours' annual leave on the same basis that a full...

  14. Does a presentation’s medium affect its message? PowerPoint, Prezi, and oral presentations

    PubMed Central

    Türkay, Selen; Kosslyn, Stephen M.

    2017-01-01

    Despite the prevalence of PowerPoint in professional and educational presentations, surprisingly little is known about how effective such presentations are. All else being equal, are PowerPoint presentations better than purely oral presentations or those that use alternative software tools? To address this question we recreated a real-world business scenario in which individuals presented to a corporate board. Participants (playing the role of the presenter) were randomly assigned to create PowerPoint, Prezi, or oral presentations, and then actually delivered the presentation live to other participants (playing the role of corporate executives). Across two experiments and on a variety of dimensions, participants evaluated PowerPoint presentations comparably to oral presentations, but evaluated Prezi presentations more favorably than both PowerPoint and oral presentations. There was some evidence that participants who viewed different types of presentations came to different conclusions about the business scenario, but no evidence that they remembered or comprehended the scenario differently. We conclude that the observed effects of presentation format are not merely the result of novelty, bias, experimenter-, or software-specific characteristics, but instead reveal a communication preference for using the panning-and-zooming animations that characterize Prezi presentations. PMID:28678855

  15. Refeeding-Induced Brown Adipose Tissue Glycogen Hyper-Accumulation in Mice Is Mediated by Insulin and Catecholamines

    PubMed Central

    Carmean, Christopher M.; Bobe, Alexandria M.; Yu, Justin C.; Volden, Paul A.; Brady, Matthew J.

    2013-01-01

    Brown adipose tissue (BAT) generates heat during adaptive thermogenesis through a combination of oxidative metabolism and uncoupling protein 1-mediated electron transport chain uncoupling, using both free-fatty acids and glucose as substrate. Previous rat-based work in 1942 showed that prolonged partial fasting followed by refeeding led to a dramatic, transient increase in glycogen stores in multiple fat depots. In the present study, the protocol was replicated in male CD1 mice, resulting in a 2000-fold increase in interscapular BAT (IBAT) glycogen levels within 4–12 hours (hr) of refeeding, with IBAT glycogen stores reaching levels comparable to fed liver glycogen. Lesser effects occurred in white adipose tissues (WAT). Over the next 36 hr, glycogen levels dissipated and histological analysis revealed an over-accumulation of lipid droplets, suggesting a potential metabolic connection between glycogenolysis and lipid synthesis. 24 hr of total starvation followed by refeeding induced a robust and consistent glycogen over-accumulation similar in magnitude and time course to the prolonged partial fast. Experimentation demonstrated that hyperglycemia was not sufficient to drive glycogen accumulation in IBAT, but that elevated circulating insulin was sufficient. Additionally, pharmacological inhibition of catecholamine production reduced refeeding-induced IBAT glycogen storage, providing evidence of a contribution from the central nervous system. These findings highlight IBAT as a tissue that integrates both canonically-anabolic and catabolic stimulation for the promotion of glycogen storage during recovery from caloric deficit. The preservation of this robust response through many generations of animals not subjected to food deprivation suggests that the over-accumulation phenomenon plays a critical role in IBAT physiology. PMID:23861810

  16. Propiverine-induced accumulation of nuclear and cytosolic protein in F344 rat kidneys: Isolation and identification of the accumulating protein

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

    Dietrich, D.R.; Heussner, A.H.; O'Brien, E.

    2008-12-15

    Male and female F344 rats but not B6C3F1 mice exposed for 104 weeks to propiverine hydrochloride (1-methylpiperid-4-yl 2,2-diphenyl-2-(1-propoxy)acetate hydrochloride), used for treatment of patients with neurogenic detrusor overactivity (NDO) and overactive bladder (OAB), presented with an accumulation of proteins in the cytosol and nuclei of renal proximal tubule epithelial cells, yet despite this, no increased renal tumor incidence was observed. In order to provide an improved interpretation of these findings and a better basis for human health risk assessment, male and female F344 rats were exposed for 16 weeks to 1000 ppm propiverine in the diet, the accumulating protein wasmore » isolated from the kidneys via cytosolic and nuclear preparations or laser-capture microdissection and analyzed using molecular weight determination and mass spectrometry. The accumulating protein was found to be D-amino acid oxidase (DAAO), an enzyme involved in amino and fatty acid metabolism. Subsequent reanalysis of kidney homogenate and nuclear samples as well as tissue sections using western blot and DAAO-immunohistochemistry, confirmed the presence and localization of DAAO in propiverine-treated male and female F344 rats. The accumulation of DAAO only in rats, and the limited similarity of rat DAAO with other species, including humans, suggests a rat-specific mechanism underlying the drug-induced renal DAAO accumulation with little relevance for patients chronically treated with propiverine.« less

  17. Lentivirus-ABCG1 instillation reduces lipid accumulation and improves lung compliance in GM-CSF knock-out mice

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

    Malur, Anagha; Huizar, Isham; Wells, Greg

    2011-11-18

    Highlights: Black-Right-Pointing-Pointer Lentivirus-ABCG1 reduces lipid accumulation in lungs of GM-CSF knock-out mice. Black-Right-Pointing-Pointer Up-regulation of ABCG1 improves lung function. Black-Right-Pointing-Pointer Upregulation of ABCG1 improves surfactant metabolism. -- Abstract: We have shown decreased expression of the nuclear transcription factor, peroxisome proliferator-activated receptor-gamma (PPAR{gamma}) and the PPAR{gamma}-regulated ATP-binding cassette transporter G1 (ABCG1) in alveolar macrophages from patients with pulmonary alveolar proteinosis (PAP). PAP patients also exhibit neutralizing antibodies to granulocyte-macrophage colony stimulating factor (GM-CSF), an upregulator of PPAR{gamma}. In association with functional GM-CSF deficiency, PAP lung is characterized by surfactant-filled alveolar spaces and lipid-filled alveolar macrophages. Similar pathology characterizes GM-CSF knock-out (KO)more » mice. We reported previously that intratracheal instillation of a lentivirus (lenti)-PPAR{gamma} plasmid into GM-CSF KO animals elevated ABCG1 and reduced alveolar macrophage lipid accumulation. Here, we hypothesized that instillation of lenti-ABCG1 might be sufficient to decrease lipid accumulation and improve pulmonary function in GM-CSF KO mice. Animals received intratracheal instillation of lenti-ABCG1 or control lenti-enhanced Green Fluorescent Protein (eGFP) plasmids and alveolar macrophages were harvested 10 days later. Alveolar macrophage transduction efficiency was 79% as shown by lenti-eGFP fluorescence. Quantitative PCR analyses indicated a threefold (p = 0.0005) increase in ABCG1 expression with no change of PPAR{gamma} or ABCA1 in alveolar macrophages of lenti-ABCG1 treated mice. ABCG1 was unchanged in control lenti-eGFP and PBS-instilled groups. Oil Red O staining detected reduced intracellular neutral lipid in alveolar macrophages from lenti-ABCG1 treated mice. Extracellular cholesterol and phospholipids were also decreased as

  18. Ultrasound in athletes: emerging techniques in point-of-care practice.

    PubMed

    Yim, Eugene S; Corrado, Gianmichel

    2012-01-01

    Ultrasound offers sports medicine clinicians the potential to diagnose, treat, and manage a broad spectrum of conditions afflicting athletes. This review article highlights applications of ultrasound that hold promise as point-of-care diagnostics and therapeutic tools that can be used directly by clinicians to direct real-time management of athletes. Point-of-care ultrasound has been examined most in the context of musculoskeletal disorders in athletes, with attention given to Achilles tendinopathy, patellar tendinopathy, hip and thigh pathology, elbow tendinopathy, wrist pathology, and shoulder pain. More research has focused on therapeutic applications than diagnostic, but initial evidence has been generated in both. Preliminary evidence has been published also on abdominal ultrasound for splenic enlargement in mononucleosis, cardiopulmonary processes and hydration status, deep vein thrombosis, and bone mineral density. Further research will be required to validate these applications and to explore further applications of portable ultrasound that can be used in the care of athletes.

  19. Blood orange juice inhibits fat accumulation in mice.

    PubMed

    Titta, L; Trinei, M; Stendardo, M; Berniakovich, I; Petroni, K; Tonelli, C; Riso, P; Porrini, M; Minucci, S; Pelicci, P G; Rapisarda, P; Reforgiato Recupero, G; Giorgio, M

    2010-03-01

    To analyze the effect of the juice obtained from two varieties of sweet orange (Citrus sinensis L. Osbeck), Moro (a blood orange) and Navelina (a blond orange), on fat accumulation in mice fed a standard or a high-fat diet (HFD). Obesity was induced in male C57/Bl6 mice by feeding a HFD. Moro and Navelina juices were provided instead of water. The effect of an anthocyanin-enriched extract from Moro oranges or purified cyanidin-3-glucoside (C3G) was also analyzed. Body weight and food intake were measured regularly over a 12-week period. The adipose pads were weighted and analyzed histologically; total RNA was also isolated for microarray analysis. Dietary supplementation of Moro juice, but not Navelina juice significantly reduced body weight gain and fat accumulation regardless of the increased energy intake because of sugar content. Furthermore, mice drinking Moro juice were resistant to HFD-induced obesity with no alterations in food intake. Only the anthocyanin extract, but not the purified C3G, slightly affected fat accumulation. High-throughput gene expression analysis of fat tissues confirmed that Moro juice could entirely rescue the high fat-induced transcriptional reprogramming. Moro juice anti-obesity effect on fat accumulation cannot be explained only by its anthocyanin content. Our findings suggest that multiple components present in the Moro orange juice might act synergistically to inhibit fat accumulation.

  20. Predicting Regional Pattern of Longitudinal β-Amyloid Accumulation by Baseline PET.

    PubMed

    Guo, Tengfei; Brendel, Matthias; Grimmer, Timo; Rominger, Axel; Yakushev, Igor

    2017-04-01

    Knowledge about spatial and temporal patterns of β-amyloid (Aβ) accumulation is essential for understanding Alzheimer disease (AD) and for design of antiamyloid drug trials. Here, we tested whether the regional pattern of longitudinal Aβ accumulation can be predicted by baseline amyloid PET. Methods: Baseline and 2-y follow-up 18 F-florbetapir PET data from 58 patients with incipient and manifest dementia due to AD were analyzed. With the determination of how fast amyloid deposits in a given region relative to the whole-brain gray matter, a pseudotemporal accumulation rate for each region was calculated. The actual accumulation rate of 18 F-florbetapir was calculated from follow-up data. Results: Pseudotemporal measurements from baseline PET data explained 87% ( P < 0.001) of the variance in longitudinal accumulation rate across 62 regions. The method accurately predicted the top 10 fast and slow accumulating regions. Conclusion: Pseudotemporal analysis of baseline PET images is capable of predicting the regional pattern of longitudinal Aβ accumulation in AD at a group level. This approach may be useful in exploring spatial patterns of Aβ accumulation in other amyloid-associated disorders such as Lewy body disease and atypical forms of AD. In addition, the method allows identification of brain regions with a high accumulation rate of Aβ, which are of particular interest for antiamyloid clinical trials. © 2017 by the Society of Nuclear Medicine and Molecular Imaging.

  1. Test sensitivity is important for detecting variability in pointing comprehension in canines.

    PubMed

    Pongrácz, Péter; Gácsi, Márta; Hegedüs, Dorottya; Péter, András; Miklósi, Adám

    2013-09-01

    Several articles have been recently published on dogs' (Canis familiaris) performance in two-way object choice experiments in which subjects had to find hidden food by utilizing human pointing. The interpretation of results has led to a vivid theoretical debate about the cognitive background of human gestural signal understanding in dogs, despite the fact that many important details of the testing method have not yet been standardized. We report three experiments that aim to reveal how some procedural differences influence adult companion dogs' performance in these tests. Utilizing a large sample in Experiment 1, we provide evidence that neither the keeping conditions (garden/house) nor the location of the testing (outdoor/indoor) affect a dogs' performance. In Experiment 2, we compare dogs' performance using three different types of pointing gestures. Dogs' performance varied between momentary distal and momentary cross-pointing but "low" and "high" performer dogs chose uniformly better than chance level if they responded to sustained pointing gestures with reinforcement (food reward and a clicking sound; "clicker pointing"). In Experiment 3, we show that single features of the aforementioned "clicker pointing" method can slightly improve dogs' success rate if they were added one by one to the momentary distal pointing method. These results provide evidence that although companion dogs show a robust performance at different testing locations regardless of their keeping conditions, the exact execution of the human gesture and additional reinforcement techniques have substantial effect on the outcomes. Consequently, researchers should standardize their methodology before engaging in debates on the comparative aspects of socio-cognitive skills because the procedures they utilize may differ in sensitivity for detecting differences.

  2. Physiology and biochemistry of source-regulated protein accumulation in the wheat grain.

    PubMed

    Barneix, Atilio J

    2007-05-01

    Wheat is unique among cereals for the baking qualities of its flour, which are dependent upon the type and concentration of its proteins. As a consequence, the grain protein concentration (GPC) is one of the main determinants of wheat international market price. More than 50-70% of the final grain N is accumulated before flowering and later remobilized to the grain, N fertilization being the common practice used to produce high GPC. However, after incremental additions of N fertilizer, GPC reaches a maximum and then remains constant, without any increase in N uptake or remobilization by the crop, thus decreasing the efficiency of N fertilizer. Although, the genetic and molecular mechanisms that regulate N uptake by the roots are being clarified quickly, the regulation and physiology of N transport from the leaves to the grain remains less clear. In this review, the possible regulatory points involved in N transport to the grain and the difficulties for increasing GPC are discussed. It has been demonstrated that protein synthesis in the grain is source-limited, and that the grain can accumulate protein limited only by the amino acids provided by the phloem. It has also been shown that there is no limitation in the amino acid/sugar ratios that can be exported to the phloem. On the other hand, NO(3)(-) uptake transporters are depressed when the plant concentration of some amino acids, such as glutamine, is high. It has also been shown that a high N supply increases cytokinins concentration, preventing leaf senescence and proteolysis. Based on this information, it is postulated that there are two main regulatory points during grain filling when plant N status is ample. On the one hand, the N uptake transporters in the roots are depressed due to the high amino acids concentration in the tissues, and N uptake is low. On the other, a high amino acids concentration keeps the cytokinins level high, repressing leaf protein degradation and decreasing amino acid export to the

  3. Bladder accumulated dose in image-guided high-dose-rate brachytherapy for locally advanced cervical cancer and its relation to urinary toxicity

    NASA Astrophysics Data System (ADS)

    Zakariaee, Roja; Hamarneh, Ghassan; Brown, Colin J.; Gaudet, Marc; Aquino-Parsons, Christina; Spadinger, Ingrid

    2016-12-01

    The purpose of this study was to estimate locally accumulated dose to the bladder in multi-fraction high-dose-date (HDR) image-guided intracavitary brachytherapy (IG-ICBT) for cervical cancer, and study the locally-accumulated dose parameters as predictors of late urinary toxicity. A retrospective study of 60 cervical cancer patients who received five HDR IG-ICBT sessions was performed. The bladder outer and inner surfaces were segmented for all sessions and a bladder-wall contour point-set was created in MATLAB. The bladder-wall point-sets for each patient were registered using a deformable point-set registration toolbox called coherent point drift (CPD), and the fraction doses were accumulated. Various dosimetric and volumetric parameters were calculated using the registered doses, including r{{\\text{D}}n \\text{c{{\\text{m}}\\text{3}}}} (minimum dose to the most exposed n-cm3 volume of bladder wall), r V n Gy (wall volume receiving at least m Gy), and r\\text{EQD}{{2}n \\text{c{{\\text{m}}\\text{3}}}} (minimum equivalent biologically weighted dose to the most exposed n-cm3 of bladder wall), where n  =  1/2/5/10 and m  =  3/5/10. Minimum dose to contiguous 1 and 2 cm3 hot-spot volumes was also calculated. The unregistered dose volume histogram (DVH)-summed equivalent of r{{\\text{D}}n \\text{c{{\\text{m}}3}}} and r\\text{EQD}{{2}n \\text{c{{\\text{m}}3}}} parameters (i.e. s{{\\text{D}}n \\text{c{{\\text{m}}\\text{3}}}} and s\\text{EQD}{{2}n \\text{c{{\\text{m}}3}}} ) were determined for comparison. Late urinary toxicity was assessed using the LENT-SOMA scale, with toxicity Grade 0-1 categorized as Controls and Grade 2-4 as Cases. A two-sample t-test was used to identify the differences between the means of Control and Case groups for all parameters. A binomial logistic regression was also performed between the registered dose parameters and toxicity grouping. Seventeen patients were in the Case and 43 patients in the Control group. Contiguous

  4. Analysis of Hanle-effect signals observed in Si-channel spin accumulation devices

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

    Takamura, Yota, E-mail: takamura@spin.pe.titech.ac.jp; Department of Physical Electronics, Tokyo Institute of Technology, 2-12-1, Ookayama, Meguro-ku, Tokyo 152-8552; Akushichi, Taiju

    2014-05-07

    We reexamined curve-fitting analysis for spin-accumulation signals observed in Si-channel spin-accumulation devices, employing widely-used Lorentz functions and a new formula developed from the spin diffusion equation. A Si-channel spin-accumulation device with a high quality ferromagnetic spin injector was fabricated, and its observed spin-accumulation signals were verified. Experimentally obtained Hanle-effect signals for spin accumulation were not able to be fitted by a single Lorentz function and were reproduced by the newly developed formula. Our developed formula can represent spin-accumulation signals and thus analyze Hanle-effect signals.

  5. 40 CFR 86.436-78 - Additional service accumulation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... minimum test distance and at the useful life, and, (3) The results of the half life emission tests, when... Regulations for 1978 and Later New Motorcycles, General Provisions § 86.436-78 Additional service accumulation. (a) Additional service up to the useful life will be accumulated under the same conditions as the...

  6. 40 CFR 86.436-78 - Additional service accumulation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... minimum test distance and at the useful life, and, (3) The results of the half life emission tests, when... Regulations for 1978 and Later New Motorcycles, General Provisions § 86.436-78 Additional service accumulation. (a) Additional service up to the useful life will be accumulated under the same conditions as the...

  7. Sales effects of product health information at points of purchase: a systematic review.

    PubMed

    van 't Riet, Jonathan

    2013-03-01

    Information about healthy and unhealthy nutrients is increasingly conveyed at the point of purchase. Many studies have investigated the effects of product health information on attitudes and intentions, but the empirical evidence becomes sketchier when the focus of research is actual purchase behaviour. The present paper provides an overview of empirical evidence on the effectiveness of product health information for food products at the point of purchase. A systematic literature review was conducted. Only studies were included that assessed the effect of product health information at the point of purchase on actual purchase behaviour, using data provided by stores' sales records or obtained by investigating customer receipts as the primary outcome measure. The included studies' target group comprised supermarket clientele. Several studies found no significant effects of product health information on actual purchase behaviour. Interventions were more likely to be effective when they lasted for a longer time, when they included additional intervention components, and when they targeted the absence of unhealthy nutrients instead of or in addition to the presence of healthy nutrients. No strong evidence for the effectiveness of product health information was found. The effect of intervention duration, additional promotional activities and targeting of healthy v. unhealthy nutrients should be closely examined in future studies.

  8. Determining Greenland Ice Sheet Accumulation Rates from Radar Remote Sensing

    NASA Technical Reports Server (NTRS)

    Jezek, Kenneth C.

    2002-01-01

    An important component of NASA's Program for Arctic Regional Climate Assessment (PARCA) is a mass balance investigation of the Greenland Ice Sheet. The mass balance is calculated by taking the difference between the areally Integrated snow accumulation and the net ice discharge of the ice sheet. Uncertainties in this calculation Include the snow accumulation rate, which has traditionally been determined by interpolating data from ice core samples taken from isolated spots across the ice sheet. The sparse data associated with ice cores juxtaposed against the high spatial and temporal resolution provided by remote sensing , has motivated scientists to investigate relationships between accumulation rate and microwave observations as an option for obtaining spatially contiguous estimates. The objective of this PARCA continuation proposal was to complete an estimate of surface accumulation rate on the Greenland Ice Sheet derived from C-band radar backscatter data compiled in the ERS-1 SAR mosaic of data acquired during, September-November, 1992. An empirical equation, based on elevation and latitude, is used to determine the mean annual temperature. We examine the influence of accumulation rate, and mean annual temperature on C-band radar backscatter using a forward model, which incorporates snow metamorphosis and radar backscatter components. Our model is run over a range of accumulation and temperature conditions. Based on the model results, we generate a look-up table, which uniquely maps the measured radar backscatter, and mean annual temperature to accumulation rate. Our results compare favorably with in situ accumulation rate measurements falling within our study area.

  9. Accumulating Data to Optimally Predict Obesity Treatment (ADOPT): Recommendations from the Biological Domain.

    PubMed

    Rosenbaum, Michael; Agurs-Collins, Tanya; Bray, Molly S; Hall, Kevin D; Hopkins, Mark; Laughlin, Maren; MacLean, Paul S; Maruvada, Padma; Savage, Cary R; Small, Dana M; Stoeckel, Luke

    2018-04-01

    The responses to behavioral, pharmacological, or surgical obesity treatments are highly individualized. The Accumulating Data to Optimally Predict obesity Treatment (ADOPT) project provides a framework for how obesity researchers, working collectively, can generate the evidence base needed to guide the development of tailored, and potentially more effective, strategies for obesity treatment. The objective of the ADOPT biological domain subgroup is to create a list of high-priority biological measures for weight-loss studies that will advance the understanding of individual variability in response to adult obesity treatments. This list includes measures of body composition, energy homeostasis (energy intake and output), brain structure and function, and biomarkers, as well as biobanking procedures, which could feasibly be included in most, if not all, studies of obesity treatment. The recommended high-priority measures are selected to balance needs for sensitivity, specificity, and/or comprehensiveness with feasibility to achieve a commonality of usage and increase the breadth and impact of obesity research. The accumulation of data on key biological factors, along with behavioral, psychosocial, and environmental factors, can generate a more precise description of the interplay and synergy among them and their impact on treatment responses, which can ultimately inform the design and delivery of effective, tailored obesity treatments. © 2018 The Obesity Society.

  10. Elevated CO2 induces alteration in lignin accumulation in celery (Apium graveolens L.).

    PubMed

    Liu, Jie-Xia; Feng, Kai; Wang, Guang-Long; Xu, Zhi-Sheng; Wang, Feng; Xiong, Ai-Sheng

    2018-06-01

    Carbon dioxide (CO 2 ) is an important regulator of plant growth and development, and its proportion in the atmosphere continues to rise now. Lignin is one of the major secondary products in plants with vital biological functions. However, the relationship between CO 2 level and xylogenesis in celery is still unknown. In order to investigate the effects of increasing CO 2 concentration on lignin accumulation in celery, 'Jinnanshiqin' were exposed to two CO 2 applications, 400 (e 0 ) and 1000 μmol mol -1 (e 1 ), respectively. Plant morphology and lignin distribution in celery plants treated with elevated CO 2 did not change significantly. There was an upward trend on lignin content in celery leaves, and the transcript abundance of 12 genes involved in lignin metabolism has altered in response to elevated CO 2 . The effects of high level of CO 2 on different tissues were different. Our works confirmed that CO 2 may play an important role in lignin accumulation in celery leaves. The current study will offer new evidence to understand the regulation mechanism of lignin biosynthesis under elevated CO 2 and provide a reference to improve celery quality by adjusting the growth environment. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

  11. Developmental accumulation of inorganic polyphosphate affects germination and energetic metabolism in Dictyostelium discoideum

    PubMed Central

    Livermore, Thomas Miles; Chubb, Jonathan Robert; Saiardi, Adolfo

    2016-01-01

    Inorganic polyphosphate (polyP) is composed of linear chains of phosphate groups linked by high-energy phosphoanhydride bonds. However, this simple, ubiquitous molecule remains poorly understood. The use of nonstandardized analytical methods has contributed to this lack of clarity. By using improved polyacrylamide gel electrophoresis we were able to visualize polyP extracted from Dictyostelium discoideum. We established that polyP is undetectable in cells lacking the polyphosphate kinase (DdPpk1). Generation of this ppk1 null strain revealed that polyP is important for the general fitness of the amoebae with the mutant strain displaying a substantial growth defect. We discovered an unprecedented accumulation of polyP during the developmental program, with polyP increasing more than 100-fold. The failure of ppk1 spores to accumulate polyP results in a germination defect. These phenotypes are underpinned by the ability of polyP to regulate basic energetic metabolism, demonstrated by a 2.5-fold decrease in the level of ATP in vegetative ppk1. Finally, the lack of polyP during the development of ppk1 mutant cells is partially offset by an increase of both ATP and inositol pyrophosphates, evidence for a model in which there is a functional interplay between inositol pyrophosphates, ATP, and polyP. PMID:26755590

  12. Infrared fixed point of SU(2) gauge theory with six flavors

    NASA Astrophysics Data System (ADS)

    Leino, Viljami; Rummukainen, Kari; Suorsa, Joni; Tuominen, Kimmo; Tähtinen, Sara

    2018-06-01

    We compute the running of the coupling in SU(2) gauge theory with six fermions in the fundamental representation of the gauge group. We find strong evidence that this theory has an infrared stable fixed point at strong coupling and measure also the anomalous dimension of the fermion mass operator at the fixed point. This theory therefore likely lies close to the boundary of the conformal window and will display novel infrared dynamics if coupled with the electroweak sector of the Standard Model.

  13. Sediment accumulation and mixing in the Penobscot River and estuary, Maine.

    PubMed

    Yeager, K M; Schwehr, K A; Schindler, K J; Santschi, P H

    2018-04-16

    Mercury (Hg) was discharged in the late 1960s into the Penobscot River by the Holtra-Chem chlor-alkali production facility, which was in operation from 1967 to 2000. To assess the transport and distribution of total Hg, and recovery of the river and estuary system from Hg pollution, physical and radiochemical data were assembled from sediment cores collected from 58 of 72 coring stations sampled in 2009. These stations were located throughout the lower Penobscot River, and included four principal study regions, the Penobscot River (PBR), Mendall Marsh (MM), the Orland River (OR), and the Penobscot estuary (ES). To provide the geochronology required to evaluate sedimentary total Hg profiles, 58 of 72 sediment cores were dated using the atmospheric radionuclide tracers 137 Cs, 210 Pb, and 239,240 Pu. Sediment cores were assessed for depths of mixing, and for the determination of sediment accumulation rates using both geochemical (total Hg) and radiochemical data. At most stations, evidence for significant vertical mixing, derived from profiles of 7 Be (where possible) and porosity, was restricted to the upper ~1-3cm. Thus, historic profiles of both total Hg and radionuclides were only minimally distorted, allowing a reconstruction of their depositional history. The pulse input tracers 137 Cs and 239,240 Pu used to assess sediment accumulation rates agreed well, while the steady state tracer 210 Pb exhibited weaker agreement, likely due to irregular lateral sediment inputs. Copyright © 2018. Published by Elsevier B.V.

  14. Digital accumulators in phase and frequency tracking loops

    NASA Technical Reports Server (NTRS)

    Hinedi, Sami; Statman, Joseph I.

    1990-01-01

    Results on the effects of digital accumulators in phase and frequency tracking loops are presented. Digital accumulators or summers are used extensively in digital signal processing to perform averaging or to reduce processing rates to acceptable levels. For tracking the Doppler of high-dynamic targets at low carrier-to-noise ratios, it is shown through simulation and experiment that digital accumulators can contribute an additional loss in operating threshold. This loss was not considered in any previous study and needs to be accounted for in performance prediction analysis. Simulation and measurement results are used to characterize the loss due to the digital summers for three different tracking loops: a digital phase-locked loop, a cross-product automatic frequency tracking loop, and an extended Kalman filter. The tracking algorithms are compared with respect to their frequency error performance and their ability to maintain lock during severe maneuvers at various carrier-to-noise ratios. It is shown that failure to account for the effect of accumulators can result in an inaccurate performance prediction, the extent of which depends highly on the algorithm used.

  15. ACCUMULATION OF RADIOACTIVE STRONTIUM BY HYDROPHYTES AND DETRITUS

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

    Agre, A.L.; Telitchenko, M.M.

    1963-11-01

    Uptake and accumulation of Sr/sup 90/ was studied in several species of green algae, blue-green algae, diatoms, mosses, and in duckweed. The organdisms were placed in experimental solutions made of standing tap water into which Sr/ sup 90/ was introduced as SrCl/sub 2/. Activity of the solutions was 10/sup -8/ to 10/sup -6/ Curie per liter. Radioactivity of the organisms was determined every 25 days on a B unit with an SI-2B leadshielded end-window counter according to standard method. The values of the coefficients of Sr/sup 90/ accumulation by the hydrophytes were found to be inversely proportional to the isotopicmore » concentration of the medium. Algae had higher Sr/sup 90/ accumulation coefficients than did mosses, an the accumulation in algae was more rapid. Experiments showed that organic wastes effected 80% decontamination of the solutions, on the average. It is suggested that hydrophytes and organic wastes may consequently be used for decontamination of water containing Sr/sup 90/. (H.M.G.)« less

  16. Sludge accumulation pattern inside oxidation ditch case study.

    PubMed

    Fouad, Moharram; El-Morsy, Ahmed

    2014-01-01

    The sludge accumulation pattern of an oxidation ditch (OD) plant treating municipal wastewater was observed under dry and wet weather conditions, during 3 years of operation. The accumulation patterns along the ditches and their rates were revealed. In addition, the composition of the accumulation was investigated. Finally, the ratio of sand and volatile particles, mixed liquor suspended solids (MLSS), and mixed liquor volatile suspended solids, as well as the removal efficiency were also observed against the accumulated sludge. Further, a laboratory-scale channel was used to investigate the settleability of grit after mixing with variable values of MLSS. The observed results indicated that the economical design and operation of ODs using a velocity value between 0.3-0.35 m/s is not recommended, to avoid the settling of all solids. High values of MLSS and sludge age need high horizontal velocity (more than 0.35 m/s) and more power to avoid settling problems and system failure. The influence of flow velocity on the sludge settleability was studied, enabling better planning of future ditch design and operation.

  17. Image quality assessment metric for frame accumulated image

    NASA Astrophysics Data System (ADS)

    Yu, Jianping; Li, Gang; Wang, Shaohui; Lin, Ling

    2018-01-01

    The medical image quality determines the accuracy of diagnosis, and the gray-scale resolution is an important parameter to measure image quality. But current objective metrics are not very suitable for assessing medical images obtained by frame accumulation technology. Little attention was paid to the gray-scale resolution, basically based on spatial resolution and limited to the 256 level gray scale of the existing display device. Thus, this paper proposes a metric, "mean signal-to-noise ratio" (MSNR) based on signal-to-noise in order to be more reasonable to evaluate frame accumulated medical image quality. We demonstrate its potential application through a series of images under a constant illumination signal. Here, the mean image of enough images was regarded as the reference image. Several groups of images by different frame accumulation and their MSNR were calculated. The results of the experiment show that, compared with other quality assessment methods, the metric is simpler, more effective, and more suitable for assessing frame accumulated images that surpass the gray scale and precision of the original image.

  18. Episodic strain accumulation in southern california.

    PubMed

    Thatcher, W

    1976-11-12

    Reexamination of horizontal geodetic data in the region of recently discovered aseismic uplift has demonstrated that equally unusual horizontal crustal deformation accompanied the development of the uplift. During this time interval compressive strains were oriented roughly normal to the San Andreas fault, suggesting that the uplift produced little shear strain accumulation across this fault. On the other hand, the orientation of the anomalous shear straining is consistent with strain accumulation across northdipping range-front thrusts like the San Fernando fault. Accordingly, the horizontal and vertical crustal deformation disclosed by geodetic observation is interpreted as a short epoch of rapid strain accumulation on these frontal faults. If this interpretation is correct, thrust-type earthquakes will eventually release the accumulated strains, but the geodetic data examined here cannot be used to estimate when these events might occur. However, observation of an unusual sequence of tilts prior to 1971 on a level line lying to the north of the magnitude 6.4 San Fernando earthquake offers some promise for precursor monitoring. The data are adequately explained by a simple model of up-dip aseismic slip propagation toward the 1971 epicentral region. These observations and the simple model that accounts for them suggest a conceptually straightforward monitoring scheme to search for similar uplift and tilt precursors within the uplifted region. Such premonitory effects could be detected by a combination of frequenlty repeated short (30 to 70 km in length) level line measurements, precise gravity traverses, and continuously recording gravimeters sited to the north of the active frontal thrust faults. Once identified, such precursors could be closely followed in space and time, and might then provide effective warnings of impending potentially destructive earth-quakes.

  19. Research on stratified evolution of composite materials under four-point bending loading

    NASA Astrophysics Data System (ADS)

    Hao, M. J.; You, Q. J.; Zheng, J. C.; Yue, Z.; Xie, Z. P.

    2017-12-01

    In order to explore the effect of stratified evolution and delamination on the load capacity and service life of the composite materials under the four-point bending loading, the artificial tectonic defects of the different positions were set up. The four-point bending test was carried out, and the whole process was recorded by acoustic emission, and the damage degree of the composite layer was judged by the impact accumulation of the specimen - time-amplitude history chart, load-time-relative energy history chart, acoustic emission impact signal positioning map. The results show that the stratified defects near the surface of the specimen accelerate the process of material failure and expansion. The location of the delamination defects changes the bending performance of the composites to a great extent. The closer the stratification defects are to the surface of the specimen, the greater the damage, the worse the service capacity of the specimen.

  20. Global warming precipitation accumulation increases above the current-climate cutoff scale

    PubMed Central

    Sahany, Sandeep; Stechmann, Samuel N.; Bernstein, Diana N.

    2017-01-01

    Precipitation accumulations, integrated over rainfall events, can be affected by both intensity and duration of the storm event. Thus, although precipitation intensity is widely projected to increase under global warming, a clear framework for predicting accumulation changes has been lacking, despite the importance of accumulations for societal impacts. Theory for changes in the probability density function (pdf) of precipitation accumulations is presented with an evaluation of these changes in global climate model simulations. We show that a simple set of conditions implies roughly exponential increases in the frequency of the very largest accumulations above a physical cutoff scale, increasing with event size. The pdf exhibits an approximately power-law range where probability density drops slowly with each order of magnitude size increase, up to a cutoff at large accumulations that limits the largest events experienced in current climate. The theory predicts that the cutoff scale, controlled by the interplay of moisture convergence variance and precipitation loss, tends to increase under global warming. Thus, precisely the large accumulations above the cutoff that are currently rare will exhibit increases in the warmer climate as this cutoff is extended. This indeed occurs in the full climate model, with a 3 °C end-of-century global-average warming yielding regional increases of hundreds of percent to >1,000% in the probability density of the largest accumulations that have historical precedents. The probabilities of unprecedented accumulations are also consistent with the extension of the cutoff. PMID:28115693