Single Cell Analysis: From Technology to Biology and Medicine.

PubMed

Pan, Xinghua

2014-01-01

Single-cell analysis heralds a new era that allows "omics" analysis, notably genomics, transcriptomics, epigenomics and proteomics at the single-cell level. It enables the identification of the minor subpopulations that may play a critical role in a biological process of a population of cells, which conventionally are regarded as homogeneous. It provides an ultra-sensitive tool to clarify specific molecular mechanisms and pathways and reveal the nature of cell heterogeneity. It also facilitates the clinical investigation of patients when a very low quantity or a single cell is available for analysis, such as noninvasive prenatal diagnosis and cancer screening, and genetic evaluation for in vitro fertilization. Within a few short years, single-cell analysis, especially whole genomic sequencing and transcriptomic sequencing, is becoming robust and broadly accessible, although not yet a routine practice. Here, with single cell RNA-seq emphasized, an overview of the discipline, progresses, and prospects of single-cell analysis and its applications in biology and medicine are given with a series of logic and theoretical considerations.

Buckling behaviors of single-walled carbon nanotubes inserted with a linear carbon-atom chain.

PubMed

Zhu, Chunhua; Chen, Yinfeng; Liu, Rumeng; Zhao, Junhua

2018-08-17

Buckling behaviors of single-walled carbon nanotubes (SWCNTs) inserted with a linear carbon-atom chain (CAC) (the composite structures are also called carbon nanowires (CNWs)) under torsion and bending as well as compression are studied using molecular dynamics (MD) simulations, respectively. Our MD results show that the critical buckling angles (or strains) of CNWs under the three presented kinds of loading patterns can be two times those of corresponding independent SWCNTs for long CNWs, while the buckling improvement is not obvious for short ones. The main reason is that the radial van der Waals force between the CAC and the SWCNT is very small for a short CNW, while it increases with increasing length and then tends to a constant for a long CNW. The obtained MD results agree well with those from available theoretical models. These findings will be a great help towards understanding the stability and reliability of the special CNT structures, and designing flexible CNT-based devices.

Direct Observation of Spatiotemporal Dynamics of Short Electron Bunches in Storage Rings

NASA Astrophysics Data System (ADS)

Evain, C.; Roussel, E.; Le Parquier, M.; Szwaj, C.; Tordeux, M.-A.; Brubach, J.-B.; Manceron, L.; Roy, P.; Bielawski, S.

2017-02-01

In recent synchrotron radiation facilities, the use of short (picosecond) electron bunches is a powerful method for producing giant pulses of terahertz coherent synchrotron radiation. Here we report on the first direct observation of these pulse shapes with a few picoseconds resolution, and of their dynamics over a long time. We thus confirm in a very direct way the theories predicting an interplay between two physical processes. Below a critical bunch charge, we observe a train of identical THz pulses (a broadband Terahertz comb) stemming from the shortness of the electron bunches. Above this threshold, a large part of the emission is dominated by drifting structures, which appear through spontaneous self-organization. These challenging single-shot THz recordings are made possible by using a recently developed photonic time stretch detector with a high sensitivity. The experiment has been realized at the SOLEIL storage ring.

Ultimately short ballistic vertical graphene Josephson junctions

PubMed Central

Lee, Gil-Ho; Kim, Sol; Jhi, Seung-Hoon; Lee, Hu-Jong

2015-01-01

Much efforts have been made for the realization of hybrid Josephson junctions incorporating various materials for the fundamental studies of exotic physical phenomena as well as the applications to superconducting quantum devices. Nonetheless, the efforts have been hindered by the diffusive nature of the conducting channels and interfaces. To overcome the obstacles, we vertically sandwiched a cleaved graphene monoatomic layer as the normal-conducting spacer between superconducting electrodes. The atomically thin single-crystalline graphene layer serves as an ultimately short conducting channel, with highly transparent interfaces with superconductors. In particular, we show the strong Josephson coupling reaching the theoretical limit, the convex-shaped temperature dependence of the Josephson critical current and the exceptionally skewed phase dependence of the Josephson current; all demonstrate the bona fide short and ballistic Josephson nature. This vertical stacking scheme for extremely thin transparent spacers would open a new pathway for exploring the exotic coherence phenomena occurring on an atomic scale. PMID:25635386

A critical-like collective state leads to long-range cell communication in Dictyostelium discoideum aggregation

PubMed Central

De Palo, Giovanna; Yi, Darvin; Endres, Robert G.

2017-01-01

The transition from single-cell to multicellular behavior is important in early development but rarely studied. The starvation-induced aggregation of the social amoeba Dictyostelium discoideum into a multicellular slug is known to result from single-cell chemotaxis towards emitted pulses of cyclic adenosine monophosphate (cAMP). However, how exactly do transient, short-range chemical gradients lead to coherent collective movement at a macroscopic scale? Here, we developed a multiscale model verified by quantitative microscopy to describe behaviors ranging widely from chemotaxis and excitability of individual cells to aggregation of thousands of cells. To better understand the mechanism of long-range cell—cell communication and hence aggregation, we analyzed cell—cell correlations, showing evidence of self-organization at the onset of aggregation (as opposed to following a leader cell). Surprisingly, cell collectives, despite their finite size, show features of criticality known from phase transitions in physical systems. By comparing wild-type and mutant cells with impaired aggregation, we found the longest cell—cell communication distance in wild-type cells, suggesting that criticality provides an adaptive advantage and optimally sized aggregates for the dispersal of spores. PMID:28422986

Review of Neutrino Mass Measurements

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

Giuliani, A.; INFN-Milano, Via Valleggio 11, I-22100 Como

2006-02-08

After a brief summary of the recent achievements of neutrino physics, the concept of neutrino mass scale is clarified. The methods for the determination of the neutrino mass values are summarized and critically compared, in particular in the different and complementary contexts of cosmology, double and single beta decay. The attention is then focussed on the laboratory approaches to investigate neutrino mass. The role of neutrinoless double beta decay is explained and a short review of the present and most promising future experiments in this field is given. Single beta decay sensitivity is discussed, with brief descriptions of the KATRINmore » tritium experiment and of the recently proposed MARE rhenium project.« less

A Common Set of Core Values - The Foundation for a More Effective Joint Force

DTIC Science & Technology

2015-05-18

these codes stopped short of codifying a set of core values and instead focused on right and wrong behaviors. This adherence to sets of rules and...Armed Forces independently recognized the limitations of compliance-based rules and the criticality of establishing a strong foundation with core...institutional values vice core values? The knee -jerk reaction of the 1990s and a subsequent lack of a formal effort to institute a single set of core

Instability of superfluid Fermi gases induced by a rotonlike density mode in optical lattices

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

Yunomae, Yoshihiro; Yamamoto, Daisuke; Danshita, Ippei

2009-12-15

We study the stability of superfluid Fermi gases in deep optical lattices in the BCS-Bose-Einstein condensation (BEC) crossover at zero temperature. Within the tight-binding attractive Hubbard model, we calculate the spectrum of the low-energy Anderson-Bogoliubov (AB) mode as well as the single-particle excitations in the presence of superfluid flow in order to determine the critical velocities. To obtain the spectrum of the AB mode, we calculate the density response function in the generalized random-phase approximation applying the Green's function formalism developed by Cote and Griffin to the Hubbard model. We find that the spectrum of the AB mode is separatedmore » from the particle-hole continuum having the characteristic rotonlike minimum at short wavelength due to the strong charge-density-wave fluctuations. The energy of the rotonlike minimum decreases with increasing the lattice velocity and it reaches zero at the critical velocity which is smaller than the pair-breaking velocity. This indicates that the superfluid state is energetically unstable due to the spontaneous emission of the short-wavelength rotonlike excitations of the AB mode instead due to pair breaking. We determine the critical velocities as functions of the interaction strength across the BCS-BEC crossover regime.« less

Assessment of long-term knowledge retention following single-day simulation training for uncommon but critical obstetrical events

PubMed Central

Vadnais, Mary A.; Dodge, Laura E.; Awtrey, Christopher S.; Ricciotti, Hope A.; Golen, Toni H.; Hacker, Michele R.

2013-01-01

Objective The objectives were to determine (i) whether simulation training results in short-term and long-term improvement in the management of uncommon but critical obstetrical events and (ii) to determine whether there was additional benefit from annual exposure to the workshop. Methods Physicians completed a pretest to measure knowledge and confidence in the management of eclampsia, shoulder dystocia, postpartum hemorrhage and vacuum-assisted vaginal delivery. They then attended a simulation workshop and immediately completed a posttest. Residents completed the same posttests 4 and 12 months later, and attending physicians completed the posttest at 12 months. Physicians participated in the same simulation workshop 1 year later and then completed a final posttest. Scores were compared using paired t-tests. Results Physicians demonstrated improved knowledge and comfort immediately after simulation. Residents maintained this improvement at 1 year. Attending physicians remained more comfortable managing these scenarios up to 1 year later; however, knowledge retention diminished with time. Repeating the simulation after 1 year brought additional improvement to physicians. Conclusion Simulation training can result in short-term and contribute to long-term improvement in objective measures of knowledge and comfort level in managing uncommon but critical obstetrical events. Repeat exposure to simulation training after 1 year can yield additional benefits. PMID:22191668

Critical spreading dynamics of parity conserving annihilating random walks with power-law branching

NASA Astrophysics Data System (ADS)

Laise, T.; dos Anjos, F. C.; Argolo, C.; Lyra, M. L.

2018-09-01

We investigate the critical spreading of the parity conserving annihilating random walks model with Lévy-like branching. The random walks are considered to perform normal diffusion with probability p on the sites of a one-dimensional lattice, annihilating in pairs by contact. With probability 1 - p, each particle can also produce two offspring which are placed at a distance r from the original site following a power-law Lévy-like distribution P(r) ∝ 1 /rα. We perform numerical simulations starting from a single particle. A finite-time scaling analysis is employed to locate the critical diffusion probability pc below which a finite density of particles is developed in the long-time limit. Further, we estimate the spreading dynamical exponents related to the increase of the average number of particles at the critical point and its respective fluctuations. The critical exponents deviate from those of the counterpart model with short-range branching for small values of α. The numerical data suggest that continuously varying spreading exponents sets up while the branching process still results in a diffusive-like spreading.

A radio transmitter attachment technique for soras

USGS Publications Warehouse

Haramis, G.M.; Kearns, G.D.

2000-01-01

We modified a figure-8 leg-loop harness designed for small passerines to attach successfully 1.8-g radio transmitters over the synsacrum of migrant Soras (Porzana carolina). Because of the short caudal region of Soras, addition of a waist loop was critical to securing the transmitter while leg loops were maintained to center the package. Thin gauge (0.6-mm diameter) elastic thread proved ideal for transmitter attachment and allowed for freedom of movement and girth expansion associated with fattening during a 6-10 week stopover. Of 110 Soras radio tagged during three field seasons, only a single mortality was observed and only a single bird lost its transmitter. Migration from the study area was confirmed for 76 (69%) and suspected for another 25 birds (total 92%).

Plasmonic Nanobubbles as Tunable Cellular Probes for Cancer Theranostics

PubMed Central

Lapotko, Dmitri

2011-01-01

This review is focused on a novel cellular probe, the plasmonic nanobubble (PNB), which has the dynamically tunable and multiple functions of imaging, diagnosis, delivery, therapy and, ultimately, theranostics. The concept of theranostics was recently introduced in order to unite the clinically important stages of treatment, namely diagnosis, therapy and therapy guidance, into one single, rapid and highly accurate procedure. Cell level theranostics will have far-reaching implications for the treatment of cancer and other diseases at their earliest stages. PNBs were developed to support cell level theranostics as a new generation of on-demand tunable cellular probes. A PNB is a transient vapor nanobubble that is generated within nanoseconds around an overheated plasmonic nanoparticle with a short laser pulse. In the short term, we expect that PNB technology will be rapidly adaptable to clinical medicine, where the single cell resolution it provides will be critical for diagnosing incipient or residual disease and eliminating cancer cells, while leaving healthy cells intact. This review discusses mechanisms of plasmonic nanobubbles and their biomedical applications with the focus on cancer cell theranostics. PMID:21442036

Vapor-liquid equilibrium and critical asymmetry of square well and short square well chain fluids.

PubMed

Li, Liyan; Sun, Fangfang; Chen, Zhitong; Wang, Long; Cai, Jun

2014-08-07

The critical behavior of square well fluids with variable interaction ranges and of short square well chain fluids have been investigated by grand canonical ensemble Monte Carlo simulations. The critical temperatures and densities were estimated by a finite-size scaling analysis with the help of histogram reweighting technique. The vapor-liquid coexistence curve in the near-critical region was determined using hyper-parallel tempering Monte Carlo simulations. The simulation results for coexistence diameters show that the contribution of |t|(1-α) to the coexistence diameter dominates the singular behavior in all systems investigated. The contribution of |t|(2β) to the coexistence diameter is larger for the system with a smaller interaction range λ. While for short square well chain fluids, longer the chain length, larger the contribution of |t|(2β). The molecular configuration greatly influences the critical asymmetry: a short soft chain fluid shows weaker critical asymmetry than a stiff chain fluid with same chain length.

Current transport properties and phase diagram of a Kitaev chain with long-range pairing

NASA Astrophysics Data System (ADS)

Giuliano, Domenico; Paganelli, Simone; Lepori, Luca

2018-04-01

We describe a method to probe the quantum phase transition between the short-range topological phase and the long-range topological phase in the superconducting Kitaev chain with long-range pairing, both exhibiting subgap modes localized at the edges. The method relies on the effects of the finite mass of the subgap edge modes in the long-range regime (which survives in the thermodynamic limit) on the single-particle scattering coefficients through the chain connected to two normal leads. Specifically, we show that, when the leads are biased at a voltage V with respect to the superconducting chain, the Fano factor is either zero (in the short-range correlated phase) or 2 e (in the long-range correlated phase). As a result, we find that the Fano factor works as a directly measurable quantity to probe the quantum phase transition between the two phases. In addition, we note a remarkable "critical fractionalization effect" in the Fano factor, which is exactly equal to e along the quantum critical line. Finally, we note that a dual implementation of our proposed device makes it suitable as a generator of large-distance entangled two-particle states.

Critical short-time dynamics in a system with interacting static and diffusive populations

NASA Astrophysics Data System (ADS)

Argolo, C.; Quintino, Yan; Gleria, Iram; Lyra, M. L.

2012-01-01

We study the critical short-time dynamical behavior of a one-dimensional model where diffusive individuals can infect a static population upon contact. The model presents an absorbing phase transition from an active to an inactive state. Previous calculations of the critical exponents based on quasistationary quantities have indicated an unusual crossover from the directed percolation to the diffusive contact process universality classes. Here we show that the critical exponents governing the slow short-time dynamic evolution of several relevant quantities, including the order parameter, its relative fluctuations, and correlation function, reinforce the lack of universality in this model. Accurate estimates show that the critical exponents are distinct in the regimes of low and high recovery rates.

Updating and feature overwriting in short-term memory for timbre.

PubMed

Mercer, Tom; McKeown, Denis

2010-11-01

Previous research has demonstrated a potent, stimulus-specific form of interference in short-term auditory memory. This effect has been interpreted in terms of interitem confusion and grouping, but the present experiments suggested that interference might be a feature-specific phenomenon. Participants compared standard and comparison tones over a 10-sec interval and were required to determine whether they differed in timbre. A single interfering distractor tone was presented either 50 msec or 8 sec after the offset of the standard (Experiment 1) or 2 sec prior to its onset (Experiment 2). The distractor varied in the number of features it shared with the standard and comparison, and this proved critical, since performance on the task was greatly impaired when the distractor either consisted of novel, unshared features (Experiment 1) or contained the distinguishing feature of the comparison tone (Experiments 1 and 2). These findings were incompatible with earlier accounts of forgetting but were fully explicable by the recent timbre memory model, which associates interference in short-term auditory memory with an "updating" process and feature overwriting. These results suggest similarities with the mechanisms that underlie forgetting in verbal short-term memory.

Grouping and binding in visual short-term memory.

PubMed

Quinlan, Philip T; Cohen, Dale J

2012-09-01

Findings of 2 experiments are reported that challenge the current understanding of visual short-term memory (VSTM). In both experiments, a single study display, containing 6 colored shapes, was presented briefly and then probed with a single colored shape. At stake is how VSTM retains a record of different objects that share common features: In the 1st experiment, 2 study items sometimes shared a common feature (either a shape or a color). The data revealed a color sharing effect, in which memory was much better for items that shared a common color than for items that did not. The 2nd experiment showed that the size of the color sharing effect depended on whether a single pair of items shared a common color or whether 2 pairs of items were so defined-memory for all items improved when 2 color groups were presented. In explaining performance, an account is advanced in which items compete for a fixed number of slots, but then memory recall for any given stored item is prone to error. A critical assumption is that items that share a common color are stored together in a slot as a chunk. The evidence provides further support for the idea that principles of perceptual organization may determine the manner in which items are stored in VSTM. PsycINFO Database Record (c) 2012 APA, all rights reserved.

Short-term plasticity and long-term potentiation mimicked in single inorganic synapses

NASA Astrophysics Data System (ADS)

Ohno, Takeo; Hasegawa, Tsuyoshi; Tsuruoka, Tohru; Terabe, Kazuya; Gimzewski, James K.; Aono, Masakazu

2011-08-01

Memory is believed to occur in the human brain as a result of two types of synaptic plasticity: short-term plasticity (STP) and long-term potentiation (LTP; refs , , , ). In neuromorphic engineering, emulation of known neural behaviour has proven to be difficult to implement in software because of the highly complex interconnected nature of thought processes. Here we report the discovery of a Ag2S inorganic synapse, which emulates the synaptic functions of both STP and LTP characteristics through the use of input pulse repetition time. The structure known as an atomic switch, operating at critical voltages, stores information as STP with a spontaneous decay of conductance level in response to intermittent input stimuli, whereas frequent stimulation results in a transition to LTP. The Ag2S inorganic synapse has interesting characteristics with analogies to an individual biological synapse, and achieves dynamic memorization in a single device without the need of external preprogramming. A psychological model related to the process of memorizing and forgetting is also demonstrated using the inorganic synapses. Our Ag2S element indicates a breakthrough in mimicking synaptic behaviour essential for the further creation of artificial neural systems that emulate characteristics of human memory.

Ultrashort courses of adjuvant breast radiotherapy: wave of the future or a fool's errand?

PubMed

Khan, Atif J; Dale, Roger G; Arthur, Douglas W; Haffty, Bruce G; Todor, Dorin A; Vicini, Frank A

2012-04-15

In accelerated partial breast irradiation (APBI), the most commonly used fractionation schemes include 340 or 385 centigrays delivered in a twice daily administration. A further progression of the APBI literature has been the recent interest in extremely short courses of adjuvant radiotherapy, usually delivered by intraoperative radiotherapy techniques. This newer area of single-fraction radiotherapy approaches remains highly contentious. In particular, the recently reported TARGIT trial has been the subject of both praise and scorn, and a critical examination of the trial data and the underlying hypotheses is warranted. Short-term outcomes of the related Italian ELIOT approach have also been reported. Although the assumptions of linear quadratic formalism are likely to hold true in the range of 2 to 8 grays, equating different schedules beyond this range is problematic. A major problem of current single-fraction approaches is that the treatment doses are chosen empirically, or are based on tolerability, or on the physical dose delivery characteristics of the chosen technology rather than radiobiological rationale. This review article summarizes the current data on ultrashort courses of adjuvant breast radiotherapy and highlights both the promise and the potential pitfalls of the abbreviated treatment. Copyright © 2011 American Cancer Society.

Magnetic phase transitions and ferromagnetic short-range correlations in single-crystal Tb5Si2.2Ge1.8

NASA Astrophysics Data System (ADS)

Zou, M.; Pecharsky, V. K.; Gschneidner, K. A., Jr.; Schlagel, D. L.; Lograsso, T. A.

2008-07-01

Magnetic phase transitions in a Tb5Si2.2Ge1.8 single crystal have been studied as a function of temperature and magnetic field. Magnetic-field dependencies of the critical temperatures are highly anisotropic for both the main magnetic ordering process occurring around 120 K and a spin reorientation transition at ˜70K . Magnetic-field-induced phase transitions occur with the magnetic field applied isothermally along the a and b axes (but not along the c axis) between 1.8 and 70 K in fields below 70 kOe. Strong anisotropic thermal irreversibility is observed in the Griffiths phase regime between 120 and 200 K with applied fields ranging from 10 to 1000 Oe. Our data (1) show that the magnetic and structural phase transitions around 120 K are narrowly decoupled; (2) uncover the anisotropy of ferromagnetic short-range order in the Griffiths phase; and (3) reveal some unusual magnetic domain effects in the long-range ordered state of the Tb5Si2.2Ge1.8 compound. The temperature-magnetic field phase diagrams with field applied along the three major crystallographic directions have been constructed.

Rapid Feedforward Inhibition and Asynchronous Excitation Regulate Granule Cell Activity in the Mammalian Main Olfactory Bulb

PubMed Central

Burton, Shawn D.

2015-01-01

Granule cell-mediated inhibition is critical to patterning principal neuron activity in the olfactory bulb, and perturbation of synaptic input to granule cells significantly alters olfactory-guided behavior. Despite the critical role of granule cells in olfaction, little is known about how sensory input recruits granule cells. Here, we combined whole-cell patch-clamp electrophysiology in acute mouse olfactory bulb slices with biophysical multicompartmental modeling to investigate the synaptic basis of granule cell recruitment. Physiological activation of sensory afferents within single glomeruli evoked diverse modes of granule cell activity, including subthreshold depolarization, spikelets, and suprathreshold responses with widely distributed spike latencies. The generation of these diverse activity modes depended, in part, on the asynchronous time course of synaptic excitation onto granule cells, which lasted several hundred milliseconds. In addition to asynchronous excitation, each granule cell also received synchronous feedforward inhibition. This inhibition targeted both proximal somatodendritic and distal apical dendritic domains of granule cells, was reliably recruited across sniff rhythms, and scaled in strength with excitation as more glomeruli were activated. Feedforward inhibition onto granule cells originated from deep short-axon cells, which responded to glomerular activation with highly reliable, short-latency firing consistent with tufted cell-mediated excitation. Simulations showed that feedforward inhibition interacts with asynchronous excitation to broaden granule cell spike latency distributions and significantly attenuates granule cell depolarization within local subcellular compartments. Collectively, our results thus identify feedforward inhibition onto granule cells as a core feature of olfactory bulb circuitry and establish asynchronous excitation and feedforward inhibition as critical regulators of granule cell activity. SIGNIFICANCE STATEMENT Inhibitory granule cells are involved critically in shaping odor-evoked principal neuron activity in the mammalian olfactory bulb, yet little is known about how sensory input activates granule cells. Here, we show that sensory input to the olfactory bulb evokes a barrage of asynchronous synaptic excitation and highly reliable, short-latency synaptic inhibition onto granule cells via a disynaptic feedforward inhibitory circuit involving deep short-axon cells. Feedforward inhibition attenuates local depolarization within granule cell dendritic branches, interacts with asynchronous excitation to suppress granule cell spike-timing precision, and scales in strength with excitation across different levels of sensory input to normalize granule cell firing rates. PMID:26490853

Critical Reception of Thomas Hardy's Short Stories: Finding "The Key to the Art."

ERIC Educational Resources Information Center

Heber, Janice Stewart

Thomas Hardy has received great acclaim as a poet and novelist, but his short stories have remained largely ignored with regard to the usual short story "canon." Early reviews of Hardy's stories were mixed, but after his death the tide of critical opinion tended to turn against Hardy's stories. A significant historical factor was the…

Single Pulse Remote Raman Detection of Minerals and Organics Under Illuminated Condition from 10 Meters Distance

NASA Technical Reports Server (NTRS)

Misra, A. K.; Sharma, S. K.; Lucey, P. G.

2005-01-01

A directly coupled portable remote Raman instrument developed by the University of Hawaii has been shown here to identify several minerals, chemicals and organics from a distance of 10 m using a single laser pulse in a well illuminated background. Raman spectra, obtained during a very short period of time, of common minerals e.g., dolomite, calcite, marble, barite, gypsum, quarts, rutile, fluorapatite etc. clearly show Raman features which could be used as fingerprints for mineral identification. Raman features of organics such as benzene, cyclohexane, 2-propanol, naphthalene, etc. and other chemicals containing various functional groups like oxides, silicates, sulphates, nitrates, phosphates and carbonates were also easily detected. Ability to measure Raman spectra with a single laser pulse would be promising for future space missions where power consumption is critical and a rapid survey of the minerals with moderate to high Raman cross section might be desirable for selecting rocks that would provide high scientific return or for acquiring rocks for sample return to the Earth.

Short-term memory and critical clusterization in brain neurons spike series

NASA Astrophysics Data System (ADS)

Bershadskii, A.; Dremencov, E.; Yadid, G.

2003-06-01

A new phenomenon: critical clusterization, is observed in the neuron firing of a genetically defined rat model of depression. The critical clusterization is studied using a multiscaling analysis of the data obtained from the neurons belonging to the Red Nucleus area of the depressive brains. It is suggested that this critical phenomenon can be partially responsible for the observed ill behavior of the depressive brains: loss of short-term motor memory and slow motor reaction.

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

Kalnaus, Sergiy; Kumar, Abhishek; Lebrun-Grandie, Damien T.

Safety is a key element of any device designed to store energy, in particular electrochemical batteries, which convert energy of chemical reactions to electrical energy. Safety considerations are especially important when applied to large automotive batteries designed for propulsion of electric vehicles (EV). The high amount of energy stored in EV battery packs translates to higher probability of fire in case of severe deformation of battery compartment due to automotive crash or impact caused by road debris. While such demand for safety has resulted in heavier protection of battery enclosure, the mechanisms leading to internal short circuit due to deformationmore » of the battery are not well understood even on the level of a single electrochemical cell. Moreover, not all internal shorts result in thermal runaway, and thus a criterion for catastrophic failure needs to be developed. This report summarizes the effort to pinpoint the critical deformation necessary to trigger a short via experimental study on large format automotive Li-ion cells in a rigid spherical indentation configuration. Cases of single cells and cell stacks undergoing indentation were investigated. Mechanical properties of cell components were determined via experimental testing and served as input for constitutive models of Finite Element (FE) analysis. The ability of the model to predict the behavior of cell(s) under spherical indentation and to predict failure leading to internal short circuit was validated against experiments. The necessity of resolving pairs of negative and positive electrodes in the FE formulation is clearly demonstrated by comparing layer-resolved simulations with simulations involving batteries with homogenized material properties. Finally, a coupled solution of electrochemical-electrical-thermal (EET) problem on a Nissan Leaf battery module was demonstrated towards the goal of extending the simulations to module level.« less

The Critical Discourse Analysis of the Representation of Women and Men in Bozorg Alavi's Short Stories

ERIC Educational Resources Information Center

Rashidi, Nasser; Khormaei, Alireza; Zarei, Maryam

2014-01-01

This study takes a critical discourse analysis approach to the investigation of the representation of men and women in Bozorg Alavi's short stories. The principal aim of this study is to find how different statuses of men and women are reflected in their languages. To this end, four short stories were selected and their discursive sentences were…

Energy localization in the phi4 oscillator chain.

PubMed

Ponno, A; Ruggiero, J; Drigo, E; De Luca, J

2006-05-01

We study energy localization in a finite one-dimensional phi(4) oscillator chain with initial energy in a single oscillator of the chain. We numerically calculate the effective number of degrees of freedom sharing the energy on the lattice as a function of time. We find that for energies smaller than a critical value, energy equipartition among the oscillators is reached in a relatively short time. On the other hand, above the critical energy, a decreasing number of particles sharing the energy is observed. We give an estimate of the effective number of degrees of freedom as a function of the energy. Our results suggest that localization is due to the appearance, above threshold, of a breather-like structure. Analytic arguments are given, based on the averaging theory and the analysis of a discrete nonlinear Schrödinger equation approximating the dynamics, to support and explain the numerical results.

Corresponding states law for a generalized Lennard-Jones potential.

PubMed

Orea, P; Romero-Martínez, A; Basurto, E; Vargas, C A; Odriozola, G

2015-07-14

It was recently shown that vapor-liquid coexistence densities derived from Mie and Yukawa models collapse to define a single master curve when represented against the difference between the reduced second virial coefficient at the corresponding temperature and that at the critical point. In this work, we further test this proposal for another generalization of the Lennard-Jones pair potential. This is carried out for vapor-liquid coexistence densities, surface tension, and vapor pressure, along a temperature window set below the critical point. For this purpose, we perform molecular dynamics simulations by varying the potential softness parameter to produce from very short to intermediate attractive ranges. We observed all properties to collapse and yield master curves. Moreover, the vapor-liquid curve is found to share the exact shape of the Mie and attractive Yukawa. Furthermore, the surface tension and the logarithm of the vapor pressure are linear functions of this difference of reduced second virial coefficients.

Short term memory for single surface features and bindings in ageing: A replication study.

PubMed

Isella, Valeria; Molteni, Federica; Mapelli, Cristina; Ferrarese, Carlo

2015-06-01

In the present study we replicated a previous experiment investigating visuo-spatial short term memory binding in young and older healthy individuals, in the attempt to verify the pattern of impairment that can be observed in normal elderly for short term memory for single items vs short term memory for bindings. Assessing a larger sample size (25 young and 25 older subjects), using a more appropriate measure of accuracy for a change detection task (A'), and adding the evaluation of speed of performance, we confirmed that old normals show a decline in short term memory for bindings of shape and colour that is of comparable extent, and not major, to the decline in memory for single shapes and single colours. The absence of a specific deficit of short term memory for conjunctions of surface features seems to distinguish cognitive ageing from Alzheimer's Disease. Copyright © 2015 Elsevier Inc. All rights reserved.

Single mode, short cavity, Pb-salt diode lasers operating in the 5, 10, and 30-microns spectral regions

NASA Technical Reports Server (NTRS)

Linden, K. J.

1985-01-01

Pb-salt diode lasers are being used as frequency-tunable infrared sources in high resolution spectroscopy and heterodyne detection applications. Recent advances in short cavity, stripe-geometry laser configurations have led to significant increases in maximum CW operating temperature, single mode operation, and increased single mode tuning range. This paper describes short cavity, stripe geometry lasers operating in the 5, 10, and 30-microns spectral regions, with single mode tuning ranges of over 6/cm.

A short, structured skills training course for critical care physiotherapists in a lower-middle income country.

PubMed

Tunpattu, Sanjeewa; Newey, Victoria; Sigera, Chathurani; De Silva, Pubudu; Goonarathna, Amal; Aluthge, Iranga; Thambavita, Pasan; Perera, Rohan; Meegahawatte, Amila; Isaam, Ilhaam; Dondorp, Arjen M; Haniffa, Rashan

2018-01-10

The aim of this article is to describe the delivery and acceptability of a short, structured training course for critical care physiotherapy and its effects on the knowledge and skills of the participants in Sri Lanka, a lower-middle income country. The two-day program combining short didactic sessions with small group workshops and skills stations was developed and delivered by local facilitators in partnership with an overseas specialist physiotherapist trainer. The impact was assessed using pre/post-course self-assessment, pre/post-course multiple-choice-question (MCQ) papers, and an end-of-course feedback questionnaire. Fifty-six physiotherapists (26% of critical care physiotherapists in Sri Lanka) participated. Overall confidence in common critical care physiotherapy skills improved from 11.6% to 59.2% in pre/post-training self-assessments, respectively. Post-course MCQ scores (mean score = 63.2) and percentage of passes (87.5%) were higher than pre-course scores (mean score = 36.6; percentage of passes = 12.5%). Overall feedback was very positive as 75% of the participants were highly satisfied with the course's contribution to improved critical care knowledge. This short, structured, critical care focused physiotherapy training has potential benefit to participating physiotherapists. Further, it provides an evidence that collaborative program can be planned and conducted successfully in a resource poor setting. This sustainable short course model may be adaptable to other resource-limited settings.

19 CFR 351.206 - Critical circumstances.

Code of Federal Regulations, 2010 CFR

2010-04-01

... DUTIES Antidumping and Countervailing Duty Procedures § 351.206 Critical circumstances. (a) Introduction... the imports during the “relatively short period” (see paragraph (i) of this section) have increased by..., the Secretary will not consider the imports massive. (i) Relatively short period. Under section 705(a...

Development of practical high temperature superconducting wire for electric power application

NASA Technical Reports Server (NTRS)

Hawsey, Robert A.; Sokolowski, Robert S.; Haldar, Pradeep; Motowidlo, Leszek R.

1995-01-01

The technology of high temperature superconductivity has gone from beyond mere scientific curiousity into the manufacturing environment. Single lengths of multifilamentary wire are now produced that are over 200 meters long and that carry over 13 amperes at 77 K. Short-sample critical current densities approach 5 x 104 A/sq cm at 77 K. Conductor requirements such as high critical current density in a magnetic field, strain-tolerant sheathing materials, and other engineering properties are addressed. A new process for fabricating round BSCCO-2212 wire has produced wires with critical current densities as high as 165,000 A/sq cm at 4.2 K and 53,000 A/sq cm at 40 K. This process eliminates the costly, multiple pressing and rolling steps that are commonly used to develop texture in the wires. New multifilamentary wires with strengthened sheathing materials have shown improved yield strengths up to a factor of five better than those made with pure silver. Many electric power devices require the wire to be formed into coils for production of strong magnetic fields. Requirements for coils and magnets for electric power applications are described.

Disordered Kitaev chains with long-range pairing.

PubMed

Cai, Xiaoming

2017-03-22

We study the competition of disorder and superconductivity for a generalized Kitaev model in incommensurate potentials. The generalized Kitaev model describes one dimensional spinless fermions with long-range p-wave superconducting pairing, which decays with distance l as a power law  ∼[Formula: see text]. We focus on the transition from the topological superconducting phase to the topologically trivial Anderson localized phase, and effects of the exponent α on this phase transition. In the topological superconducting phase, for a system under open boundary condition the amplitude of zero-mode Majorana fermion has a hybrid exponential-algebraic decay as the distance increases from the edge. In the Anderson localized phase, some single-particle states remain critical for very strong disorders and the number of critical states increases as α decreases. In addition, except for critical disorders, the correlation function always has an exponential decay at the short range and an algebraic decay at the long range. Phase transition points are also numerically determined and the topological phase transition happens earlier at a smaller disorder strength for a system with smaller α.

Microstructural control and superconducting properties of YBCO melt textured single crystals

NASA Astrophysics Data System (ADS)

Jongprateep, Oratai

The high temperature superconductor has great potential for practical applications such as superconducting energy storage systems. Since the levitation force, required specifically for these applications, largely depends on the critical current density and loop size of the superconducting current, large-sized single crystals with high critical current density are desired. To achieve the goal in fabricating YBa2Cu3O 7-delta (Y123) samples suitable for the applications, detailed and systematic studies are required to gain further understanding of the crystal growth and flux pinning mechanisms. This research is aimed at constituting a contribution to the knowledge base for the Y123 high temperature superconductor field by extending the study of processing conditions involved in controlling the microstructure of the Y123 superconductors for the enhancement of crystal growth and superconductor properties. Relations among processing parameters, microstructure, crystal growth, and critical current density of Y123 superconductors have been established. The experimental results reveal that low heating rate and short holding time can lead to refinement of Y2BaCuO5 (Y211) particles, which is strongly favorable to enhancement of the crystal growth and electrical properties of the Y123 superconductors. It was observed that relatively large Y123 crystals (17-22 mm in size) can be obtained with fine needle-shaped Y211 particles, processed with low heating rate and short holding time at the maximum temperatures. Additionally, the research also formulated a technique to fabricate Y123 superconductors with improved electrical properties required for the practical applications. By incorporating additives such as BaCeO3, BaSnO 3, Pt and Nd2O3 into Y123 superconductors, refinement of Y211 particles occurs. In addition, secondary phase particles with sizes in sub-micrometer and nanometer range can be formed in the Y123 superconductors. The interfaces between the Y123 matrix and these Y211 or secondary phase particles are believed to act as flux pinning sites and to enhance the critical current density (Jc) in the superconductor. The results showed that formation of secondary phase inclusions in Y123 by doping with BaCeO3, BaSnO 3, Pt or Nd2O3 result in enhancement of J c due to the effective flux pinning.

Infinite-disorder critical points of models with stretched exponential interactions

NASA Astrophysics Data System (ADS)

Juhász, Róbert

2014-09-01

We show that an interaction decaying as a stretched exponential function of distance, J(l)˜ e-cl^a , is able to alter the universality class of short-range systems having an infinite-disorder critical point. To do so, we study the low-energy properties of the random transverse-field Ising chain with the above form of interaction by a strong-disorder renormalization group (SDRG) approach. We find that the critical behavior of the model is controlled by infinite-disorder fixed points different from those of the short-range model if 0 < a < 1/2. In this range, the critical exponents calculated analytically by a simplified SDRG scheme are found to vary with a, while, for a > 1/2, the model belongs to the same universality class as its short-range variant. The entanglement entropy of a block of size L increases logarithmically with L at the critical point but, unlike the short-range model, the prefactor is dependent on disorder in the range 0 < a < 1/2. Numerical results obtained by an improved SDRG scheme are found to be in agreement with the analytical predictions. The same fixed points are expected to describe the critical behavior of, among others, the random contact process with stretched exponentially decaying activation rates.

Design of an oil squeeze film damper bearing for a multimass flexible-rotor bearing system

NASA Technical Reports Server (NTRS)

Cunningham, R. E.; Gunter, E. J., Jr.; Fleming, D. P.

1975-01-01

A single-mass flexible-rotor analysis was used to optimize the stiffness and damping of a flexible support for a symmetric five-mass rotor. The flexible, damped support attenuates the amplitudes of motions and forces transmitted to the support bearings when the rotor operates through and above its first bending critical speed. An oil squeeze film damper was designed based on short bearing lubrication theory. The damper design was verified by an unbalance response computer program. Rotor amplitudes were reduced by a factor of 16 and loads reduced by a factor of 36 compared with the same rotor with rigid bearing supports.

Design of a squeeze-film damper for a multi-mass flexible rotor

NASA Technical Reports Server (NTRS)

Cunningham, R. E.; Fleming, D. P.; Gunter, E. J.

1975-01-01

A single mass flexible rotor analysis was used to optimize the stiffness and damping of a flexible support for a symmetric five-mass rotor. The flexible support attenuates the rotor motions and forces transmitted to the support bearings when the rotor operates through and above its first bending critical speed. An oil squeeze-film damper was designed based on short bearing lubrication theory. The damper design was verified by an unbalance response computer program. Rotor amplitudes were reduced by a factor of 16 and loads reduced by a factor of 36 compared with the same rotor on rigid bearing supports.

Customer service and practice profitability.

PubMed

Levin, Roger P

2004-06-01

Customer service, one of the major dental practice business systems, is critical to your short- and long-term success. The world will keep changing, but customer service is not a fad that can go out of style. If anything, it becomes even more important, year after year, as your customers expect more service and better treatment. Your goal is to provide extensive customer service, with 100% of patients enjoying a great experience every single time they interact with your practice. The "Wow" experience helps your practice grow. You want your patients to become your friends. Why? Because friends refer friends. When your patients become your friends, higher profitability is the inevitable result.

Analysis of acute naproxen administration on memory in young adults: A randomized, double-blind, placebo-controlled study.

PubMed

Wilson, Jack H; Criss, Amy H; Spangler, Sean A; Walukevich, Katherine; Hewett, Sandra

2017-10-01

Nonsteroidal anti-inflammatory drugs work by non-selectively inhibiting cyclooxygenase enzymes. Evidence indicates that metabolites of the cyclooxygenase pathway play a critical role in the process of learning and memory. We evaluated whether acute naproxen treatment impairs short-term working memory, episodic memory, or semantic memory in a young, healthy adult population. Participants received a single dose of placebo or naproxen (750 mg) in random order separated by 7-10 days. Two hours following administration, participants completed five memory tasks. The administration of acute high-dose naproxen had no effect on memory in healthy young adults.

Use of multi-frequency, multi-polarization, multi-angle airborne radars for class discrimination in a southern temperature forest

NASA Technical Reports Server (NTRS)

Mehta, N. C.

1984-01-01

The utility of radar scatterometers for discrimination and characterization of natural vegetation was investigated. Backscatter measurements were acquired with airborne multi-frequency, multi-polarization, multi-angle radar scatterometers over a test site in a southern temperate forest. Separability between ground cover classes was studied using a two-class separability measure. Very good separability is achieved between most classes. Longer wavelength is useful in separating trees from non-tree classes, while shorter wavelength and cross polarization are helpful for discrimination among tree classes. Using the maximum likelihood classifier, 50% overall classification accuracy is achieved using a single, short-wavelength scatterometer channel. Addition of multiple incidence angles and another radar band improves classification accuracy by 20% and 50%, respectively, over the single channel accuracy. Incorporation of a third radar band seems redundant for vegetation classification. Vertical transmit polarization is critically important for all classes.

High spin cycles: topping the spin record for a single molecule verging on quantum criticality

NASA Astrophysics Data System (ADS)

Baniodeh, Amer; Magnani, Nicola; Lan, Yanhua; Buth, Gernot; Anson, Christopher E.; Richter, Johannes; Affronte, Marco; Schnack, Jürgen; Powell, Annie K.

2018-03-01

The cyclisation of a short chain into a ring provides fascinating scenarios in terms of transforming a finite array of spins into a quasi-infinite structure. If frustration is present, theory predicts interesting quantum critical points, where the ground state and thus low-temperature properties of a material change drastically upon even a small variation of appropriate external parameters. This can be visualised as achieving a very high and pointed summit where the way down has an infinity of possibilities, which by any parameter change will be rapidly chosen, in order to reach the final ground state. Here we report a mixed 3d/4f cyclic coordination cluster that turns out to be very near or even at such a quantum critical point. It has a ground state spin of S = 60, the largest ever observed for a molecule (120 times that of a single electron). [Fe10Gd10(Me-tea)10(Me-teaH)10(NO3)10].20MeCN forms a nano-torus with alternating gadolinium and iron ions with a nearest neighbour Fe-Gd coupling and a frustrating next-nearest neighbour Fe-Fe coupling. Such a spin arrangement corresponds to a cyclic delta or saw-tooth chain, which can exhibit unusual frustration effects. In the present case, the quantum critical point bears a `flatland' of tens of thousands of energetically degenerate states between which transitions are possible at no energy costs with profound caloric consequences. Entropy-wise the energy flatland translates into the pointed summit overlooking the entropy landscape. Going downhill several target states can be reached depending on the applied physical procedure which offers new prospects for addressability.

Derivation of two functional X chromosome centromeres from a single break bisecting the centromere of origin: Implications for centromere structure

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

Schonberg, S.A.; Quarles, C.; Tifft, C.

1994-09-01

The precise nature of the functional human centromeric sequences remains a matter of some controversy. Evidence has accumulated over the past several years that directly implicates alphoid repeats as a critical component. We report a child with dysmorphic features consistent with the recently described small ring X syndrome, with a constitutional karyotype that addresses this issue. At 5 1/2 months, the patient was a small, hypotonic, delayed female with brachycephaly, a broad forehead, prominent nasal root, synophorous, small mouth, and cup-shaped ears with prominent lobules, as well as microcornea, and pendular nystagmus. Hand abnormalities included single palmar creases and shortmore » tapered fingers. In addition to mosaicism for a small ring chromosome derived from the proximal short arm of the X, the proband has, in all cells, a monocentric isochromosome for the long arm of the X. The karyotype is interpreted as 46,X,iso(Xq)/47,X,iso(Xq),r(Xp11cen). We present routine karyotypic and FISH analysis of the rearranged X chromosomes. We propose that the only mechanism consistent with this karyotype is that of a two-break rearrangement with one break bisecting a centromere in such a way as to retain functional centromeric activity in each of the separated regions. The second break, proximal in the short arm, allows for ring chromosome formation with the bisected centromere. The iso(Xq) arises by the classical mechanism of post-replication sister-reunion. The formation of two functional centromeres by a single break through the {open_quotes}parental{close_quotes} centromere indicates that the functional activity must be in a repeated component of the centromeric DNA and argues strongly against the requirement for any single gene in cis orientation.« less

Complications and Short-Term Explantation Rate Following Artificial Urinary Sphincter Implantation: Results from a Large Middle European Multi-Institutional Case Series.

PubMed

Kretschmer, Alexander; Hüsch, Tanja; Thomsen, Frauke; Kronlachner, Dominik; Obaje, Alice; Anding, Ralf; Pottek, Tobias; Rose, Achim; Olianas, Roberto; Friedl, Alexander; Hübner, Wilhelm; Homberg, Roland; Pfitzenmaier, Jesco; Grein, Ulrich; Queissert, Fabian; Naumann, Carsten Maik; Schweiger, Josef; Wotzka, Carola; Nyarangi-Dix, Joanne N; Hofmann, Torben; Seiler, Roland; Haferkamp, Axel; Bauer, Ricarda M

2016-01-01

Background/Aims/Objectives: To analyze perioperative complication and short-term explantation rates after perineal or penoscrotal single-cuff and double-cuff artificial urinary sphincter (AUS) implantation in a large middle European multi-institutional patient cohort. 467 male patients with stress urinary incontinence underwent implantation of a perineal single-cuff (n = 152), penoscrotal single-cuff (n = 99), or perineal double-cuff (n = 216) AUS between 2010 and 2012. Postoperative complications and 6-month explantation rates were assessed. For statistical analysis, Fisher's exact test and Kruskal-Wallis rank sum test, and a multiple logistic regression model were used (p < 0.05). Compared to perineal single-cuff AUS, penoscrotal single-cuff implantation led to significantly increased short-term explantation rates (8.6% (perineal) vs. 19.2% (penoscrotal), p = 0.019). The postoperative infection rate was significantly higher after double-cuff compared to single-cuff implantation (6.0% (single-cuff) vs. 13.9% (double-cuff), p = 0.019). The short-term explantation rate after primary double-cuff placement was 6.5% (p = 0.543 vs. perineal single-cuff). In multivariate analysis, the penoscrotal approach (p = 0.004), intraoperative complications (p = 0.005), postoperative bleeding (p = 0.011), and perioperative infection (p < 0.001) were independent risk factors for short-term explantation. Providing data from a large contemporary multi-institutional patient cohort from high-volume and low-volume institutions, our results reflect the current standard of care in middle Europe. We indicate that the penoscrotal approach is an independent risk factor for increased short-term explantation rates. © 2016 S. Karger AG, Basel.

Single Molecule Spectroscopy of Amino Acids and Peptides by Recognition Tunneling

PubMed Central

Zhao, Yanan; Ashcroft, Brian; Zhang, Peiming; Liu, Hao; Sen, Suman; Song, Weisi; Im, JongOne; Gyarfas, Brett; Manna, Saikat; Biswas, Sovan; Borges, Chad; Lindsay, Stuart

2014-01-01

The human proteome has millions of protein variants due to alternative RNA splicing and post-translational modifications, and variants that are related to diseases are frequently present in minute concentrations. For DNA and RNA, low concentrations can be amplified using the polymerase chain reaction, but there is no such reaction for proteins. Therefore, the development of single molecule protein sequencing is a critical step in the search for protein biomarkers. Here we show that single amino acids can be identified by trapping the molecules between two electrodes that are coated with a layer of recognition molecules and measuring the electron tunneling current across the junction. A given molecule can bind in more than one way in the junction, and we therefore use a machine-learning algorithm to distinguish between the sets of electronic ‘fingerprints’ associated with each binding motif. With this recognition tunneling technique, we are able to identify D, L enantiomers, a methylated amino acid, isobaric isomers, and short peptides. The results suggest that direct electronic sequencing of single proteins could be possible by sequentially measuring the products of processive exopeptidase digestion, or by using a molecular motor to pull proteins through a tunnel junction integrated with a nanopore. PMID:24705512

Magnetic penetration-depth measurements of a suppressed superfluid density of superconducting Ca0.5Na0.5Fe2As2 single crystals by proton irradiation

NASA Astrophysics Data System (ADS)

Kim, Jeehoon; Haberkorn, N.; Graf, M. J.; Usov, I.; Ronning, F.; Civale, L.; Nazaretski, E.; Chen, G. F.; Yu, W.; Thompson, J. D.; Movshovich, R.

2012-10-01

We report on the dramatic effect of random point defects, produced by proton irradiation, on the superfluid density ρs in superconducting Ca0.5Na0.5Fe2As2 single crystals. The magnitude of the suppression is inferred from measurements of the temperature-dependent magnetic penetration depth λ(T) using magnetic force microscopy. Our findings indicate that a radiation dose of 2×1016 cm-2 produced by 3 MeV protons results in a reduction of the superconducting critical temperature Tc by approximately 10%. In contrast, ρs(0) is suppressed by approximately 60%. This breakdown of the Abrikosov-Gorkov theory may be explained by the so-called “Swiss cheese model,” which accounts for the spatial suppression of the order parameter near point defects similar to holes in Swiss cheese. Both the slope of the upper critical field and the penetration depth λ(T/Tc)/λ(0) exhibit similar temperature dependences before and after irradiation. This may be due to a combination of the highly disordered nature of Ca0.5Na0.5Fe2As2 with large intraband and simultaneous interband scattering as well as the s±-wave nature of short coherence length superconductivity.

Protein kinetic signatures of the remodeling heart following isoproterenol stimulation.

PubMed

Lam, Maggie P Y; Wang, Ding; Lau, Edward; Liem, David A; Kim, Allen K; Ng, Dominic C M; Liang, Xiangbo; Bleakley, Brian J; Liu, Chenguang; Tabaraki, Jason D; Cadeiras, Martin; Wang, Yibin; Deng, Mario C; Ping, Peipei

2014-04-01

Protein temporal dynamics play a critical role in time-dimensional pathophysiological processes, including the gradual cardiac remodeling that occurs in early-stage heart failure. Methods for quantitative assessments of protein kinetics are lacking, and despite knowledge gained from single-protein studies, integrative views of the coordinated behavior of multiple proteins in cardiac remodeling are scarce. Here, we developed a workflow that integrates deuterium oxide (2H2O) labeling, high-resolution mass spectrometry (MS), and custom computational methods to systematically interrogate in vivo protein turnover. Using this workflow, we characterized the in vivo turnover kinetics of 2,964 proteins in a mouse model of β-adrenergic-induced cardiac remodeling. The data provided a quantitative and longitudinal view of cardiac remodeling at the molecular level, revealing widespread kinetic regulations in calcium signaling, metabolism, proteostasis, and mitochondrial dynamics. We translated the workflow to human studies, creating a reference dataset of 496 plasma protein turnover rates from 4 healthy adults. The approach is applicable to short, minimal label enrichment and can be performed on as little as a single biopsy, thereby overcoming critical obstacles to clinical investigations. The protein turnover quantitation experiments and computational workflow described here should be widely applicable to large-scale biomolecular investigations of human disease mechanisms with a temporal perspective.

Protein kinetic signatures of the remodeling heart following isoproterenol stimulation

PubMed Central

Lam, Maggie P.Y.; Wang, Ding; Lau, Edward; Liem, David A.; Kim, Allen K.; Ng, Dominic C.M.; Liang, Xiangbo; Bleakley, Brian J.; Liu, Chenguang; Tabaraki, Jason D.; Cadeiras, Martin; Wang, Yibin; Deng, Mario C.; Ping, Peipei

2014-01-01

Protein temporal dynamics play a critical role in time-dimensional pathophysiological processes, including the gradual cardiac remodeling that occurs in early-stage heart failure. Methods for quantitative assessments of protein kinetics are lacking, and despite knowledge gained from single-protein studies, integrative views of the coordinated behavior of multiple proteins in cardiac remodeling are scarce. Here, we developed a workflow that integrates deuterium oxide (2H2O) labeling, high-resolution mass spectrometry (MS), and custom computational methods to systematically interrogate in vivo protein turnover. Using this workflow, we characterized the in vivo turnover kinetics of 2,964 proteins in a mouse model of β-adrenergic–induced cardiac remodeling. The data provided a quantitative and longitudinal view of cardiac remodeling at the molecular level, revealing widespread kinetic regulations in calcium signaling, metabolism, proteostasis, and mitochondrial dynamics. We translated the workflow to human studies, creating a reference dataset of 496 plasma protein turnover rates from 4 healthy adults. The approach is applicable to short, minimal label enrichment and can be performed on as little as a single biopsy, thereby overcoming critical obstacles to clinical investigations. The protein turnover quantitation experiments and computational workflow described here should be widely applicable to large-scale biomolecular investigations of human disease mechanisms with a temporal perspective. PMID:24614109

From individual spiking neurons to population behavior: Systematic elimination of short-wavelength spatial modes

NASA Astrophysics Data System (ADS)

Steyn-Ross, Moira L.; Steyn-Ross, D. A.

2016-02-01

Mean-field models of the brain approximate spiking dynamics by assuming that each neuron responds to its neighbors via a naive spatial average that neglects local fluctuations and correlations in firing activity. In this paper we address this issue by introducing a rigorous formalism to enable spatial coarse-graining of spiking dynamics, scaling from the microscopic level of a single type 1 (integrator) neuron to a macroscopic assembly of spiking neurons that are interconnected by chemical synapses and nearest-neighbor gap junctions. Spiking behavior at the single-neuron scale ℓ ≈10 μ m is described by Wilson's two-variable conductance-based equations [H. R. Wilson, J. Theor. Biol. 200, 375 (1999), 10.1006/jtbi.1999.1002], driven by fields of incoming neural activity from neighboring neurons. We map these equations to a coarser spatial resolution of grid length B ℓ , with B ≫1 being the blocking ratio linking micro and macro scales. Our method systematically eliminates high-frequency (short-wavelength) spatial modes q ⃗ in favor of low-frequency spatial modes Q ⃗ using an adiabatic elimination procedure that has been shown to be equivalent to the path-integral coarse graining applied to renormalization group theory of critical phenomena. This bottom-up neural regridding allows us to track the percolation of synaptic and ion-channel noise from the single neuron up to the scale of macroscopic population-average variables. Anticipated applications of neural regridding include extraction of the current-to-firing-rate transfer function, investigation of fluctuation criticality near phase-transition tipping points, determination of spatial scaling laws for avalanche events, and prediction of the spatial extent of self-organized macrocolumnar structures. As a first-order exemplar of the method, we recover nonlinear corrections for a coarse-grained Wilson spiking neuron embedded in a network of identical diffusively coupled neurons whose chemical synapses have been disabled. Intriguingly, we find that reblocking transforms the original type 1 Wilson integrator into a type 2 resonator whose spike-rate transfer function exhibits abrupt spiking onset with near-vertical takeoff and chaotic dynamics just above threshold.

Advancing Sexuality Studies: A Short Course on Sexuality Theory and Research Methodologies

ERIC Educational Resources Information Center

Fletcher, Gillian; Dowsett, Gary W.; Duncan, Duane; Slavin, Sean; Corboz, Julienne

2013-01-01

Critical Sexuality Studies is an emerging field of academic enquiry linked to an international network of advocacy agencies, activists, and political issues. This paper reports on the development of an advanced short course in sexuality theory and research, drawing on Critical Sexuality Studies and aiming directly at academics in developing…

Serial consolidation of orientation information into visual short-term memory.

PubMed

Liu, Taosheng; Becker, Mark W

2013-06-01

Previous research suggests that there is a limit to the rate at which items can be consolidated in visual short-term memory (VSTM). This limit could be due to either a serial or a limited-capacity parallel process. Historically, it has proven difficult to distinguish between these two types of processes. In the present experiment, we took a novel approach that allowed us to do so. Participants viewed two oriented gratings either sequentially or simultaneously and reported one of the gratings' orientation via method of adjustment. Performance was worse for the simultaneous than for the sequential condition. We fit the data with a mixture model that assumes performance is limited by a noisy memory representation plus random guessing. Critically, the serial and limited-capacity parallel processes made distinct predictions regarding the model's guessing and memory-precision parameters. We found strong support for a serial process, which implies that one can consolidate only a single orientation into VSTM at a time.

OsSNDP1, a Sec14-nodulin domain-containing protein, plays a critical role in root hair elongation in rice.

PubMed

Huang, Jin; Kim, Chul Min; Xuan, Yuan-hu; Park, Soon Ju; Piao, Hai Long; Je, Byoung Il; Liu, Jingmiao; Kim, Tae Ho; Kim, Bo-Kyeong; Han, Chang-Deok

2013-05-01

Rice is cultivated in water-logged paddy lands. Thus, rice root hairs on the epidermal layers are exposed to a different redox status of nitrogen species, organic acids, and metal ions than root hairs growing in drained soil. To identify genes that play an important role in root hair growth, a forward genetics approach was used to screen for short-root-hair mutants. A short-root-hair mutant was identified and isolated by using map-based cloning and sequencing. The mutation arose from a single amino acid substitution of OsSNDP1 (Oryza sativa Sec14-nodulin domain protein), which shows high sequence homology with Arabidopsis COW1/AtSFH1 and encodes a phosphatidylinositol transfer protein (PITP). By performing complementation assays with Atsfh1 mutants, we demonstrated that OsSNDP1 is involved in growth of root hairs. Cryo-scanning electron microscopy was utilized to further characterize the effect of the Ossndp1 mutation on root hair morphology. Aberrant morphogenesis was detected in root hair elongation and maturation zones. Many root hairs were branched and showed irregular shapes due to bulged nodes. Many epidermal cells also produced dome-shaped root hairs, which indicated that root hair elongation ceased at an early stage. These studies showed that PITP-mediated phospholipid signaling and metabolism is critical for root hair elongation in rice.

Practical Entanglement Estimation for Spin-System Quantum Simulators.

PubMed

Marty, O; Cramer, M; Plenio, M B

2016-03-11

We present practical methods to measure entanglement for quantum simulators that can be realized with trapped ions, cold atoms, and superconducting qubits. Focusing on long- and short-range Ising-type Hamiltonians, we introduce schemes that are applicable under realistic experimental conditions including mixedness due to, e.g., noise or temperature. In particular, we identify a single observable whose expectation value serves as a lower bound to entanglement and that may be obtained by a simple quantum circuit. As such circuits are not (yet) available for every platform, we investigate the performance of routinely measured observables as quantitative entanglement witnesses. Possible applications include experimental studies of entanglement scaling in critical systems and the reliable benchmarking of quantum simulators.

Folding of a helix is critically stabilized by polarization of backbone hydrogen bonds: study in explicit water.

PubMed

Duan, Li L; Gao, Ya; Mei, Ye; Zhang, Qing G; Tang, Bo; Zhang, John Z H

2012-03-15

Multiple single-trajectory molecular dynamics (MD) simulation at room temperature (300 K) in explicit water was carried out to study the folding dynamics of an α-helix (PDB 2I9M ) using a polarized charge scheme that includes electronic polarization of backbone hydrogen bonds. Starting from an extended conformation, the 17-residue peptide was successfully folded into the native structure (α-helix) between 80 and 130 ns with a root-mean-square deviation of ~1.0 Å. Analysis of the time-dependent trajectories revealed that helix formation of the peptide started at the terminals and progressed toward the center of the peptide. For comparison, MD trajectories generated under various versions of standard AMBER force fields failed to show any significant or stable helix formation in our simulation. Our result shows clear evidence that the electronic polarization of backbone hydrogen bonds energetically stabilizes the helix formation and is critical to the stable folding of the short helix structure. © 2012 American Chemical Society

Does a Business Curriculum Develop or Filter Critical Thinking?

ERIC Educational Resources Information Center

Coleman, B. Jay; Mason, Paul; Steagall, Jeffrey W.

2012-01-01

We investigate whether a business curriculum develops critical thinking ability or at least serves as a filter for critical thinking (i.e., students who cannot think critically tend not to progress toward graduation). We measure critical thinking by performance on the Watson-Glaser Critical Thinking Appraisal Short Form which was administered to a…

Critical congenital heart disease--utility of routine screening for chromosomal and other extracardiac malformations.

PubMed

Baker, Kimberly; Sanchez-de-Toledo, Joan; Munoz, Ricardo; Orr, Richard; Kiray, Shareen; Shiderly, Dana; Clemens, Michele; Wearden, Peter; Morell, Victor O; Chrysostomou, Constantinos

2012-01-01

Objective.  Infants with critical congenital heart disease (CHD) can have genetic and other extracardiac malformations, which add to the short- and long-term risk of morbidity and perhaps mortality. We sought to examine our center's practice of screening for extracardiac anomalies and to determine the yield of these tests among specific cardiac diagnostic categories. Design.  Retrospective review of infants admitted to the cardiac intensive care unit with a new diagnosis of CHD. Subjects were categorized into six groups: septal defects (SD), conotruncal defects (CTD), single-ventricle physiology (SV), left-sided obstructive lesions (LSO), right-sided obstructive lesions (RSO), and "other" (anomalous pulmonary venous return, Ebstein's anomaly). Screening modalities included genetic testing (karyotype and fluorescent in situ hybridization for 22q11.2 deletion), renal ultrasound (RUS), and head ultrasound (HUS). Results.  One hundred forty-one patients were identified. The incidence of cardiac anomalies was: CTD (36%), SD (18%), SV (18%), LSO (14%), RSO (3%), and "other" (8%). Overall 14% had an abnormal karyotype, 5% had a deletion for 22q11.2, 28% had an abnormal RUS and 22% had abnormal HUS. Patients in SD and SV had the highest incidence of abnormal karyotype (36% and 17%); 22q11.2 deletion was present only in CTD and LSO groups (9% and 7%, respectively); abnormal RUS and HUS were seen relatively uniformly in all categories. Premature infants had significantly higher incidence of renal 43% vs. 24%, and intracranial abnormalities 46% vs. 16%. Conclusion.  Infants with critical CHD and particularly premature infants have high incidence of genetic and other extracardiac anomalies. Universal screening for these abnormalities with ultrasonographic and genetic testing maybe warranted because early detection could impact short and long-term outcomes. © 2011 Wiley Periodicals, Inc.

Regulation of mIκBNS stability through PEST-mediated degradation by proteasome

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

Park, Koog Chan; Jeong, Jiyeong; Kim, Keun Il, E-mail: kikim@sookmyung.ac.kr

2014-01-24

Highlights: • mIκBNS is degraded rapidly by proteasome without ubiquitylation. • N-terminal PEST sequence is responsible for the unstable nature of mIκBNS. • PEST sequence is not critical for nuclear localization of mIκBNS. • There is single bona fide NLS at the C-terminus of mIκBNS. - Abstract: Negative regulatory proteins in a cytokine signaling play a critical role in restricting unwanted excess activation of the signaling pathway. At the same time, negative regulatory proteins need to be removed rapidly from cells to respond properly to the next incoming signal. A nuclear IκB protein called IκBNS is known to inhibit amore » subset of NF-κB target genes upon its expression by NF-κB activation. Here, we show a mechanism to control the stability of mIκBNS which might be important for cells to prepare the next round signaling. We found that mIκBNS is a short-lived protein of which the stability is controlled by proteasome, independent of ubiquitylation process. We identified that the N-terminal PEST sequence in mIκBNS was critical for the regulation of stability.« less

Intrinsic pinning and the critical current scaling of clean epitaxial Fe(Se,Te) thin films

NASA Astrophysics Data System (ADS)

Iida, Kazumasa; Hänisch, Jens; Reich, Elke; Kurth, Fritz; Hühne, Ruben; Schultz, Ludwig; Holzapfel, Bernhard; Ichinose, Ataru; Hanawa, Masafumi; Tsukada, Ichiro; Schulze, Michael; Aswartham, Saicharan; Wurmehl, Sabine; Büchner, Bernd

2013-03-01

We report on the transport properties of clean, epitaxial Fe(Se,Te) thin films prepared on Fe-buffered MgO (001) single crystalline substrates by pulsed laser deposition. Near Tc a steep slope of the upper critical field for H||ab was observed (74.1 T/K), leading to a very short out-of-plane coherence length, ξc(0), of 0.2 nm, yielding 2ξc(0)≈0.4nm. This value is shorter than the interlayer distance (0.605 nm) between the Fe-Se(Te) planes, indicative of modulation of the superconducting order parameter along the c axis. An inverse correlation between the power law exponent N of the electric field-current density(E-J) curve and the critical current density Jc has been observed at 4 K, when the orientation of H was close to the ab plane. These results prove the presence of intrinsic pinning in Fe(Se,Te). A successful scaling of the angular dependent Jc and the corresponding exponent N can be realized by the anisotropic Ginzburg Landau approach with appropriate Γ values 2˜3.5. The temperature dependence of Γ behaves almost identically to that of the penetration depth anisotropy.

Application of amorphous carbon based materials as antireflective coatings on crystalline silicon solar cells

NASA Astrophysics Data System (ADS)

da Silva, D. S.; Côrtes, A. D. S.; Oliveira, M. H.; Motta, E. F.; Viana, G. A.; Mei, P. R.; Marques, F. C.

2011-08-01

We report on the investigation of the potential application of different forms of amorphous carbon (a-C and a-C:H) as an antireflective coating for crystalline silicon solar cells. Polymeric-like carbon (PLC) and hydrogenated diamond-like carbon films were deposited by plasma enhanced chemical vapor deposition. Tetrahedral amorphous carbon (ta-C) was deposited by the filtered cathodic vacuum arc technique. Those three different amorphous carbon structures were individually applied as single antireflective coatings on conventional (polished and texturized) p-n junction crystalline silicon solar cells. Due to their optical properties, good results were also obtained for double-layer antireflective coatings based on PLC or ta-C films combined with different materials. The results are compared with a conventional tin dioxide (SnO2) single-layer antireflective coating and zinc sulfide/magnesium fluoride (ZnS/MgF2) double-layer antireflective coatings. An increase of 23.7% in the short-circuit current density, Jsc, was obtained using PLC as an antireflective coating and 31.7% was achieved using a double-layer of PLC with a layer of magnesium fluoride (MgF2). An additional increase of 10.8% was obtained in texturized silicon, representing a total increase (texturization + double-layer) of about 40% in the short-circuit current density. The potential use of these materials are critically addressed considering their refractive index, optical bandgap, absorption coefficient, hardness, chemical inertness, and mechanical stability.

Challenges in characterization of photonic crystal fibers

NASA Astrophysics Data System (ADS)

Borzycki, Krzysztof; Kobelke, Jens; Mergo, Pawel; Schuster, Kay

2011-05-01

We present experience with photonic crystal fiber (PCF) characterization during COST Action 299, focusing on phenomena causing errors and ways to mitigate them. PCFs developed at IPHT Jena (Germany; UMCS Lublin, Poland), designed for single mode operation were coupled to test instruments by fusion splicing to intermediate lengths of telecom single mode fibers (SMF). PCF samples were short (0.5-100 m), with 20-70 dB/km attenuation at 1310 nm and 1550 nm. Optical Time Domain Reflectometer (OTDR) was best for measuring loss as most PCFs produced strong backscattering, while variable splice losses and difficulties with PCF cleaving for optical power measurements made cutback and insertion loss measurements inaccurate. Experience with PCF handling and cleaving is also reviewed. Quality of splices to fiber under test was critical. Excitation of higher order modes produced strong "noise" during measurements of polarization parameters like PMD or PDL. Multimode propagation and vibration-induced interference precluded testing of fine dependence of PMD on temperature or strain, causing random variations comparable to true changes of PMD. OTDR measurements were not affected, but testing of short fiber sections with very different backscattering intensities puts special demands on instrument performance. Temperature testing of liquid-infiltrated PCF was time-consuming, as settling of parameters after temperature change took up to 40 minutes. PCFs were fragile, breaking below 2% linear expansion, sometimes in unusual way when twisted.

ECONOMIC IMPACT ANALYSIS OF GDOT’S SHORT LINE RAILROADS

DOT National Transportation Integrated Search

2018-04-01

Short line railroads are critical to Georgias transportation infrastructure and support the efficient movement of goods into and out of the State. Twenty-nine short line railroads operate in Georgia, six of which operate either partially or totall...

Interplay between population firing stability and single neuron dynamics in hippocampal networks

PubMed Central

Slomowitz, Edden; Styr, Boaz; Vertkin, Irena; Milshtein-Parush, Hila; Nelken, Israel; Slutsky, Michael; Slutsky, Inna

2015-01-01

Neuronal circuits' ability to maintain the delicate balance between stability and flexibility in changing environments is critical for normal neuronal functioning. However, to what extent individual neurons and neuronal populations maintain internal firing properties remains largely unknown. In this study, we show that distributions of spontaneous population firing rates and synchrony are subject to accurate homeostatic control following increase of synaptic inhibition in cultured hippocampal networks. Reduction in firing rate triggered synaptic and intrinsic adaptive responses operating as global homeostatic mechanisms to maintain firing macro-stability, without achieving local homeostasis at the single-neuron level. Adaptive mechanisms, while stabilizing population firing properties, reduced short-term facilitation essential for synaptic discrimination of input patterns. Thus, invariant ongoing population dynamics emerge from intrinsically unstable activity patterns of individual neurons and synapses. The observed differences in the precision of homeostatic control at different spatial scales challenge cell-autonomous theory of network homeostasis and suggest the existence of network-wide regulation rules. DOI: http://dx.doi.org/10.7554/eLife.04378.001 PMID:25556699

Fast two-photon imaging of subcellular voltage dynamics in neuronal tissue with genetically encoded indicators.

PubMed

Chamberland, Simon; Yang, Helen H; Pan, Michael M; Evans, Stephen W; Guan, Sihui; Chavarha, Mariya; Yang, Ying; Salesse, Charleen; Wu, Haodi; Wu, Joseph C; Clandinin, Thomas R; Toth, Katalin; Lin, Michael Z; St-Pierre, François

2017-07-27

Monitoring voltage dynamics in defined neurons deep in the brain is critical for unraveling the function of neuronal circuits but is challenging due to the limited performance of existing tools. In particular, while genetically encoded voltage indicators have shown promise for optical detection of voltage transients, many indicators exhibit low sensitivity when imaged under two-photon illumination. Previous studies thus fell short of visualizing voltage dynamics in individual neurons in single trials. Here, we report ASAP2s, a novel voltage indicator with improved sensitivity. By imaging ASAP2s using random-access multi-photon microscopy, we demonstrate robust single-trial detection of action potentials in organotypic slice cultures. We also show that ASAP2s enables two-photon imaging of graded potentials in organotypic slice cultures and in Drosophila . These results demonstrate that the combination of ASAP2s and fast two-photon imaging methods enables detection of neural electrical activity with subcellular spatial resolution and millisecond-timescale precision.

Motility modes of the parasite Trypanosoma brucei

NASA Astrophysics Data System (ADS)

Temel, Fatma Zeynep; Qu, Zijie; McAllaster, Michael; de Graffenried, Christopher; Breuer, Kenneth

2015-11-01

The parasitic single-celled protozoan Trypanosoma brucei causes African Sleeping Sickness, which is a fatal disease in humans and animals that threatens more than 60 million people in 36 African countries. Cell motility plays a critical role in the developmental phases and dissemination of the parasite. Unlike many other motile cells such as bacteria Escherichia coli or Caulobacter crescentus, the flagellum of T. brucei is attached along the length of its awl-like body, producing a unique mode of motility that is not fully understood or characterized. Here, we report on the motility of T. brucei, which swims using its single flagellum employing both rotating and undulating propulsion modes. We tracked cells in real-time in three dimensions using fluorescent microscopy. Data obtained from experiments using both short-term tracking within the field of view and long-term tracking using a tracking microscope were analyzed. Motility modes and swimming speed were analyzed as functions of cell size, rotation rate and undulation pattern. Research supported by NSF.

Variation of Cats under Domestication: Genetic Assignment of Domestic Cats to Breeds and Worldwide Random Bred Populations

PubMed Central

Kurushima, J. D.; Lipinski, M. J.; Gandolfi, B.; Froenicke, L.; Grahn, J. C.; Grahn, R. A.; Lyons, L. A.

2012-01-01

Summary Both cat breeders and the lay public have interests in the origins of their pets, not only in the genetic identity of the purebred individuals, but also the historical origins of common household cats. The cat fancy is a relatively new institution with over 85% of its 40–50 breeds arising only in the past 75 years, primarily through selection on single-gene aesthetic traits. The short, yet intense cat breed history poses a significant challenge to the development of a genetic marker-based breed identification strategy. Using different breed assignment strategies and methods, 477 cats representing 29 fancy breeds were analysed with 38 short tandem repeats, 148 intergenic and five phenotypic single nucleotide polymorphisms. Results suggest the frequentist method of Paetkau (accuracy single nucleotide polymorphisms = 0.78, short tandem repeats = 0.88) surpasses the Bayesian method of Rannala and Mountain (single nucleotide polymorphisms = 0.56, short tandem repeats = 0.83) for accurate assignment of individuals to the correct breed. Additionally, a post-assignment verification step with the five phenotypic single nucleotide polymorphisms accurately identified between 0.31 and 0.58 of the mis-assigned individuals raising the sensitivity of assignment with the frequentist method to 0.89 and 0.92 single nucleotide polymorphisms and short tandem repeats respectively. This study provides a novel multi-step assignment strategy and suggests that, despite their short breed history and breed family groupings, a majority of cats can be assigned to their proper breed or population of origin, i.e. race. PMID:23171373

C. elegans positive butanone learning, short-term, and long-term associative memory assays.

PubMed

Kauffman, Amanda; Parsons, Lance; Stein, Geneva; Wills, Airon; Kaletsky, Rachel; Murphy, Coleen

2011-03-11

The memory of experiences and learned information is critical for organisms to make choices that aid their survival. C. elegans navigates its environment through neuron-specific detection of food and chemical odors, and can associate nutritive states with chemical odors, temperature, and the pathogenicity of a food source. Here, we describe assays of C. elegans associative learning and short- and long-term associative memory. We modified an aversive olfactory learning paradigm to instead produce a positive response; the assay involves starving ~400 worms, then feeding the worms in the presence of the AWC neuron-sensed volatile chemoattractant butanone at a concentration that elicits a low chemotactic index (similar to Toroyama et al.). A standard population chemotaxis assay1 tests the worms' attraction to the odorant immediately or minutes to hours after conditioning. After conditioning, wild-type animals' chemotaxis to butanone increases ~0.6 Chemotaxis Index units, its "Learning Index". Associative learning is dependent on the presence of both food and butanone during training. Pairing food and butanone for a single conditioning period ("massed training") produces short-term associative memory that lasts ~2 hours. Multiple conditioning periods with rest periods between ("spaced training") yields long-term associative memory (<40 hours), and is dependent on the cAMP Response Element Binding protein (CREB), a transcription factor required for long-term memory across species. Our protocol also includes image analysis methods for quick and accurate determination of chemotaxis indices. High-contrast images of animals on chemotaxis assay plates are captured and analyzed by worm counting software in MatLab. The software corrects for uneven background using a morphological tophat transformation. Otsu's method is then used to determine a threshold to separate worms from the background. Very small particles are removed automatically and larger non-worm regions (plate edges or agar punches) are removed by manual selection. The software then estimates the size of single worm by ignoring regions that are above a specified maximum size and taking the median size of the remaining regions. The number of worms is then estimated by dividing the total area identified as occupied by worms by the estimated size of a single worm. We have found that learning and short- and long-term memory can be distinguished, and that these processes share similar key molecules with higher organisms. Our assays can quickly test novel candidate genes or molecules that affect learning and short- or long-term memory in C. elegans that are relevant across species.

A representative-sandwich model for simultaneously coupled mechanical-electrical-thermal simulation of a lithium-ion cell under quasi-static indentation tests

DOE PAGES

Zhang, Chao; Santhanagopalan, Shriram; Sprague, Michael A.; ...

2015-08-29

The safety behavior of lithium-ion batteries under external mechanical crush is a critical concern, especially during large scale deployment. We previously presented a sequentially coupled mechanical-electrical-thermal modeling approach for studying mechanical abuse induced short circuit. Here in this work, we study different mechanical test conditions and examine the interaction between mechanical failure and electrical-thermal responses, by developing a simultaneous coupled mechanical-electrical-thermal model. The present work utilizes a single representative-sandwich (RS) to model the full pouch cell with explicit representations for each individual component such as the active material, current collector, separator, etc. Anisotropic constitutive material models are presented to describemore » the mechanical properties of active materials and separator. The model predicts accurately the force-strain response and fracture of battery structure, simulates the local failure of separator layer, and captures the onset of short circuit for lithium-ion battery cell under sphere indentation tests with three different diameters. Electrical-thermal responses to the three different indentation tests are elaborated and discussed. Lastly, numerical studies are presented to show the potential impact of test conditions on the electrical-thermal behavior of the cell after the occurrence of short circuit.« less

A representative-sandwich model for simultaneously coupled mechanical-electrical-thermal simulation of a lithium-ion cell under quasi-static indentation tests

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

Zhang, Chao; Santhanagopalan, Shriram; Sprague, Michael A.

The safety behavior of lithium-ion batteries under external mechanical crush is a critical concern, especially during large scale deployment. We previously presented a sequentially coupled mechanical-electrical-thermal modeling approach for studying mechanical abuse induced short circuit. Here in this work, we study different mechanical test conditions and examine the interaction between mechanical failure and electrical-thermal responses, by developing a simultaneous coupled mechanical-electrical-thermal model. The present work utilizes a single representative-sandwich (RS) to model the full pouch cell with explicit representations for each individual component such as the active material, current collector, separator, etc. Anisotropic constitutive material models are presented to describemore » the mechanical properties of active materials and separator. The model predicts accurately the force-strain response and fracture of battery structure, simulates the local failure of separator layer, and captures the onset of short circuit for lithium-ion battery cell under sphere indentation tests with three different diameters. Electrical-thermal responses to the three different indentation tests are elaborated and discussed. Lastly, numerical studies are presented to show the potential impact of test conditions on the electrical-thermal behavior of the cell after the occurrence of short circuit.« less

Optimising experimental design for MEG resting state functional connectivity measurement.

PubMed

Liuzzi, Lucrezia; Gascoyne, Lauren E; Tewarie, Prejaas K; Barratt, Eleanor L; Boto, Elena; Brookes, Matthew J

2017-07-15

The study of functional connectivity using magnetoencephalography (MEG) is an expanding area of neuroimaging, and adds an extra dimension to the more common assessments made using fMRI. The importance of such metrics is growing, with recent demonstrations of their utility in clinical research, however previous reports suggest that whilst group level resting state connectivity is robust, single session recordings lack repeatability. Such robustness is critical if MEG measures in individual subjects are to prove clinically valuable. In the present paper, we test how practical aspects of experimental design affect the intra-subject repeatability of MEG findings; specifically we assess the effect of co-registration method and data recording duration. We show that the use of a foam head-cast, which is known to improve co-registration accuracy, increased significantly the between session repeatability of both beamformer reconstruction and connectivity estimation. We also show that recording duration is a critical parameter, with large improvements in repeatability apparent when using ten minute, compared to five minute recordings. Further analyses suggest that the origin of this latter effect is not underpinned by technical aspects of source reconstruction, but rather by a genuine effect of brain state; short recordings are simply inefficient at capturing the canonical MEG network in a single subject. Our results provide important insights on experimental design and will prove valuable for future MEG connectivity studies. Copyright © 2016. Published by Elsevier Inc.

Space Qualification Test of a-Silicon Solar Cell Modules

NASA Technical Reports Server (NTRS)

Kim, Q.; Lawton, R. A.; Manion, S. J.; Okuno, J. O.; Ruiz, R. P.; Vu, D. T.; Vu, D. T.; Kayali, S. A.; Jeffrey, F. R.

2004-01-01

The basic requirements of solar cell modules for space applications are generally described in MIL-S-83576 for the specific needs of the USAF. However, the specifications of solar cells intended for use on space terrestrial applications are not well defined. Therefore, this qualifications test effort was concentrated on critical areas specific to the microseismometer probe which is intended to be included in the Mars microprobe programs. Parameters that were evaluated included performance dependence on: illuminating angles, terrestrial temperatures, lifetime, as well as impact landing conditions. Our qualification efforts were limited to these most critical areas of concern. Most of the tested solar cell modules have met the requirements of the program except the impact tests. Surprisingly, one of the two single PIN 2 x 1 amorphous solar cell modules continued to function even after the 80000G impact tests. The output power parameters, Pout, FF, Isc and Voc, of the single PIN amorphous solar cell module were found to be 3.14 mW, 0.40, 9.98 mA and 0.78 V, respectively. These parameters are good enough to consider the solar module as a possible power source for the microprobe seismometer. Some recommendations were made to improve the usefulness of the amorphous silicon solar cell modules in space terrestrial applications, based on the results obtained from the intensive short term lab test effort.

A simulator investigation of the use of digital data link for pilot/ATC communications in a single pilot operation

NASA Technical Reports Server (NTRS)

Hinton, David A.; Lohr, Gary W.

1988-01-01

Studies have shown that radio communications between pilots and air traffic control contribute to high pilot workload and are subject to various errors. These errors result from congestion on the voice radio channel, and missed and misunderstood messages. The use of digital data link has been proposed as a means of reducing this workload and error rate. A critical factor, however, in determining the potential benefit of data link will be the interface between future data link systems and the operator of those systems, both in the air and on the ground. The purpose of this effort was to evaluate the pilot interface with various levels of data link capability, in simulated general aviation, single-pilot instrument flight rule operations. Results show that the data link reduced demands on pilots' short-term memory, reduced the number of communication transmissions, and permitted the pilots to more easily allocate time to critical cockpit tasks while receiving air traffic control messages. The pilots who participated unanimously indicated a preference for data link communications over voice-only communications. There were, however, situations in which the pilot preferred the use of voice communications, and the ability for pilots to delay processing the data link messages, during high workload events, caused delays in the acknowledgement of messages to air traffic control.

MDS Task Force on Mild Cognitive Impairment in Parkinson’s disease: Critical Review of PD-MCI

PubMed Central

Litvan, I; Aarsland, D; Adler, CH; Goldman, JG; Kulisevsky, J; Mollenhauer, B; Rodriguez-Oroz, MC; Tröster, AI; Weintraub, D

2011-01-01

Background There is controversy regarding the definition and characteristics of mild cognitive impairment in Parkinson’s disease. Objective The Movement Disorders Society commissioned a Task Force to critically evaluate the literature and determine the frequency and characteristics of Parkinson’s disease-mild cognitive impairment and its association with dementia. Methods Comprehensive PubMed literature review using systematic inclusion and exclusion criteria. Results A mean of 26.7% (range, 18.9–38.2%) of non-demented Parkinson’s disease patients have mild cognitive impairment. The frequency of Parkinson’s disease mild cognitive impairment increases with age, disease duration, and disease severity. Impairments occur in a range of cognitive domains, but single domain impairment is more common than multiple domain impairment, and within single domain impairment, non-amnestic is more common than amnestic impairment. A high proportion of patients with Parkinson’s disease-mild cognitive impairment progress to dementia in a relatively short period of time. Conclusions The primary conclusions of the Task Force are that: (1) Parkinson’s disease-mild cognitive impairment is common; (2) there is significant heterogeneity within Parkinson’s disease-mild cognitive impairment in the number and types of cognitive domain impairments; (3) Parkinson’s disease-mild cognitive impairment appears to place patients at risk of progressing to dementia; and (4) formal diagnostic criteria for Parkinson’s disease-mild cognitive impairment are needed. PMID:21661055

Effect of short-range correlations on the single proton 3s1/2 wave function in 206Pb

NASA Astrophysics Data System (ADS)

Shlomo, S.; Talmi, I.; Anders, M. R.; Bonasera, G.

2018-02-01

We consider the experimental data for difference, Δρc (r), between the charge density distributions of the isotones 206Pb - 205Tl, deduced by analysis of elastic electron scattering measurements and corresponds to the shell model 3s1/2 proton orbit. We investigate the effects of two-body short-range correlations. This is done by: (a) Determining the corresponding single particle potential (mean-field), employing a novel method, directly from the single particle proton density and its first and second derivatives. We also carried out least-square fits to parametrized single particle potentials; (b) Determining the short-range correlations effect by employing the Jastrow correlated many-body wave function to derive a correlation factor for the single particle density distribution. The 3s 1/2 wave functions of the determined potentials reproduce fairly well the experimental data within the quoted errors. The calculated charge density difference, Δρc (r), obtained with the inclusion of the short-range correlation effect does not reproduce the experimental data.

DNA methylation regulates neurophysiological spatial representation in memory formation

PubMed Central

Roth, Eric D.; Roth, Tania L.; Money, Kelli M.; SenGupta, Sonda; Eason, Dawn E.; Sweatt, J. David

2015-01-01

Epigenetic mechanisms including altered DNA methylation are critical for altered gene transcription subserving synaptic plasticity and the retention of learned behavior. Here we tested the idea that one role for activity-dependent altered DNA methylation is stabilization of cognition-associated hippocampal place cell firing in response to novel place learning. We observed that a behavioral protocol (spatial exploration of a novel environment) known to induce hippocampal place cell remapping resulted in alterations of hippocampal Bdnf DNA methylation. Further studies using neurophysiological in vivo single unit recordings revealed that pharmacological manipulations of DNA methylation decreased long-term but not short-term place field stability. Together our data highlight a role for DNA methylation in regulating neurophysiological spatial representation and memory formation. PMID:25960947

Structural Characterization of β-Agostic Bonds in Pd-Catalyzed Polymerization

DOE PAGES

Xu, Hongwei; Hu, Chunhua Tony; Wang, Xiaoping; ...

2017-10-23

β-agostic Pd complexes are critical intermediates in catalytic reactions, such as olefin polymerization and Heck reactions. Pd β-agostic complexes, however, have eluded structural characterization, due to the fact that these highly unstable molecules are difficult to isolate. In this paper, we report the single-crystal X-ray and neutron diffraction characterization of β-agostic (α-diimine)Pd–ethyl intermediates in polymerization. Short C α–C β distances and acute Pd–C α–C β bond angles combined serve as unambiguous evidence for the β-agostic interaction. Finally, characterization of the agostic structure and the kinetic barrier for β-H elimination offer important insight into the fundamental understanding of agostic bonds andmore » the mechanism of polymerization.« less

Structural Characterization of β-Agostic Bonds in Pd-Catalyzed Polymerization

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

Xu, Hongwei; Hu, Chunhua Tony; Wang, Xiaoping

β-agostic Pd complexes are critical intermediates in catalytic reactions, such as olefin polymerization and Heck reactions. Pd β-agostic complexes, however, have eluded structural characterization, due to the fact that these highly unstable molecules are difficult to isolate. In this paper, we report the single-crystal X-ray and neutron diffraction characterization of β-agostic (α-diimine)Pd–ethyl intermediates in polymerization. Short C α–C β distances and acute Pd–C α–C β bond angles combined serve as unambiguous evidence for the β-agostic interaction. Finally, characterization of the agostic structure and the kinetic barrier for β-H elimination offer important insight into the fundamental understanding of agostic bonds andmore » the mechanism of polymerization.« less

A critical thinking disposition scale for nurses: short form.

PubMed

Hwang, Shiow-Y; Yen, Miaofen; Lee, Bih-O; Huang, Mei-C; Tseng, Hung-F

2010-11-01

The aim of this study was to test the Chinese version of the Critical Thinking Disposition Inventory (CTDI-CV) among nurses in Taiwan. Critical thinking is the use of purposeful self-regulatory judgments to identify patient's problems and provide patient care. Critical thinking influences nurses' decision making. To date, no inventory to understand nurse's critical thinking disposition has been developed. This was a survey design with a stratified random sampling to test the reliability and validity of the CTDI-CV. The participants comprised 864 registered nurses who were chosen by stratified random sampling from seven hospitals in Taiwan. Data were collected through self-administered structured questionnaires. A new scale, short form (SF) CTDI-CV, contains 18 items with three subscales: 'systematic analysis', 'thinking within the box' and 'thinking out of the box', was generated from the analysis with 44% explained variance. Cronbach's alpha coefficients and intra-class correlation coefficients for overall and subscale were above 0.8. Goodness-of-fit test for the final model of SF-CTDI-CV revealed an acceptable result in the overall fit (χ(2)/df = 4.04, p < 0.05, GFI = 0.93, AGFI = 0.91, SRMR = 0.076, RMSEA = 0.059). On the basis of these results, the SF-CTDI-CV is a reliable instrument for assessing critical thinking disposition for nurses. A short and valid critical thinking instrument for nurses will facilitate critical thinking research in the clinical practice arena. When designing continuing education activities, clinical educators will be able to efficiently and effectively evaluate the quality of critical thinking among practicing nurses. © 2010 Blackwell Publishing Ltd.

Improved space object detection using short-exposure image data with daylight background.

PubMed

Becker, David; Cain, Stephen

2018-05-10

Space object detection is of great importance in the highly dependent yet competitive and congested space domain. The detection algorithms employed play a crucial role in fulfilling the detection component in the space situational awareness mission to detect, track, characterize, and catalog unknown space objects. Many current space detection algorithms use a matched filter or a spatial correlator on long-exposure data to make a detection decision at a single pixel point of a spatial image based on the assumption that the data follow a Gaussian distribution. Long-exposure imaging is critical to detection performance in these algorithms; however, for imaging under daylight conditions, it becomes necessary to create a long-exposure image as the sum of many short-exposure images. This paper explores the potential for increasing detection capabilities for small and dim space objects in a stack of short-exposure images dominated by a bright background. The algorithm proposed in this paper improves the traditional stack and average method of forming a long-exposure image by selectively removing short-exposure frames of data that do not positively contribute to the overall signal-to-noise ratio of the averaged image. The performance of the algorithm is compared to a traditional matched filter detector using data generated in MATLAB as well as laboratory-collected data. The results are illustrated on a receiver operating characteristic curve to highlight the increased probability of detection associated with the proposed algorithm.

Water demand forecasting: review of soft computing methods.

PubMed

Ghalehkhondabi, Iman; Ardjmand, Ehsan; Young, William A; Weckman, Gary R

2017-07-01

Demand forecasting plays a vital role in resource management for governments and private companies. Considering the scarcity of water and its inherent constraints, demand management and forecasting in this domain are critically important. Several soft computing techniques have been developed over the last few decades for water demand forecasting. This study focuses on soft computing methods of water consumption forecasting published between 2005 and 2015. These methods include artificial neural networks (ANNs), fuzzy and neuro-fuzzy models, support vector machines, metaheuristics, and system dynamics. Furthermore, it was discussed that while in short-term forecasting, ANNs have been superior in many cases, but it is still very difficult to pick a single method as the overall best. According to the literature, various methods and their hybrids are applied to water demand forecasting. However, it seems soft computing has a lot more to contribute to water demand forecasting. These contribution areas include, but are not limited, to various ANN architectures, unsupervised methods, deep learning, various metaheuristics, and ensemble methods. Moreover, it is found that soft computing methods are mainly used for short-term demand forecasting.

Confirmation of Down syndrome critical region by FISH analysis in a patient with add(21)(p11)

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

Matsumoto, Naomichi; Niikawa, Norio; Mikawa, Makoto

1995-12-04

We have studied a patient with clinical Down syndrome (DS) who has a mosaic 46, XX/46, XX, 21p+ karyotype. The patient was born at 39 weeks of gestation with a birth weight of 3,025 g to healthy parents. At age 2 months, she was diagnosed clinically to have DS; she had flat facies, upslanted palpebral fissures, epicanthal folds, telecanthus, flat nasal bridge, abnormal dentition, malformed ears, short neck, short fingers, clinodactyly with single flexion crease of the fifth fingers, hyperextension of joints, pes planus, distal axial triradii, and bilateral tibial arch patterns. Chromosome analysis showed mosaicism consisting of a normalmore » 46,XX cell line and a line with a 21p+ chromosome, the final karyotype being mos46,XX[57]/46,XX,add(21)(p11)[43]. Although the origin of an additional segment on chromosome 21 was not identified with conventional banding analyses, it was suspected to represent partial trisomy 21 on the basis of clinical manifestations. 6 refs., 2 figs.« less

Single closed contact for 0.18-micron photolithography process

NASA Astrophysics Data System (ADS)

Cheung, Cristina; Phan, Khoi A.; Chiu, Robert J.

2000-06-01

With the rapid advances of deep submicron semiconductor technology, identifying defects is converted into a challenge for different modules in the fabrication of chips. Yield engineers often do bitmap on a memory circuit array (SRAM) to identify the failure bits. This is followed by a wafer stripback to look for visual defects at each deprocessed layer for feedback to the Fab. However, to identify the root cause of a problem, Fab engineers must be able to detect similar defects either on the product wafers in process or some short loop test wafers. In the photolithography process, we recognize that the detection of defects is becoming as important as satisfying the critical dimension (CD) of the device. For a multi-level metallization chemically mechanical polish backend process, it is very difficult to detect missing contacts or via at the masking steps due to metal grain roughness, film color variation and/or previous layer defects. Often, photolithography engineer must depend on Photo Cell Monitor (PCM) and short loop experiments for controlling baseline defects and improvement. In this paper, we discuss the findings on the Poly mask PCM and the Contact mask PCM. We present the comparison between the Poly mask and the Contact mask of the I-line Phase Shifted Via mask and DUV mask process for a 0.18 micron process technology. The correlation and the different type of defects between the Contact PCM and the Poly Mask are discussed. The Contact PCM was found to be more sensitive and correlated to contact failure at sort yield better. We also dedicate to study the root cause of a single closed contact hole in the Contact mask short loop experiment for a 0.18 micron process technology. A single closed contact defect was often caused by the developer process, such as bubbles in the line, resist residue left behind, and the rinse mechanism. We also found surfactant solution helps to improve the surface tension of the wafer for the developer process and this prevents/eliminates a single closed contact hole defects. The applications and effects of using different substrates like SiON, different thicknesses of Oxides, and Poly in the Contact Photo Mask is shown. Finally, some defect troubleshooting techniques and the root cause analysis are also discussed.

Catapults fall short

NASA Astrophysics Data System (ADS)

Gibson, Marcus

2018-01-01

In reply to the news story "UK Catapults fall short, claims review of technology centres", which describes an independent review that criticized the management of the UK's network of technology innovation centres.

Study of quiet turbofan STOL aircraft for short haul transportation

NASA Technical Reports Server (NTRS)

Higgins, T. P.; Stout, E. G.; Sweet, H. S.

1973-01-01

A study of quiet turbofan short takeoff aircraft for short haul air transportation was conducted. The objectives of the study were to: (1) define representative aircraft configurations, characteristics, and costs associated with their development, (2) identify critical technology and technology related problems to be resolved in successful introduction of representative short haul aircraft, (3) determine relationships between quiet short takeoff aircraft and the economic and social viability of short haul, and (4) identify high payoff technology areas.

Unusual ferromagnetic critical behavior owing to short-range antiferromagnetic correlations in antiperovskite Cu1-xNMn3+x (0.1 ≤ x ≤ 0.4)

PubMed Central

Lin, Jianchao; Tong, Peng; Cui, Dapeng; Yang, Cheng; Yang, Jie; Lin, Shuai; Wang, Bosen; Tong, Wei; Zhang, Lei; Zou, Youming; Sun, Yuping

2015-01-01

For ferromagnets, varying from simple metals to strongly correlated oxides,the critical behaviors near the Curie temperature (TC) can be grouped into several universal classes. In this paper, we report an unusual critical behavior in manganese nitrides Cu1-xNMn3+x (0.1 ≤ x ≤ 0.4). Although the critical behavior below TC can be well described by mean field (MF) theory, robust critical fluctuations beyond the expectations of any universal classes are observed above TC in x = 0.1. The critical fluctuations become weaker when x increases, and the MF-like critical behavior is finally restored at x = 0.4. In addition, the paramagnetic susceptibility of all the samples deviates from the Curie-Weiss (CW) law just above TC. This deviation is gradually smeared as x increases. The short-range antiferromagnetic ordering above TC revealed by our electron spin resonance measurement explains both the unusual critical behavior and the breakdown of the CW law. PMID:25604754

Single-pair fluorescence resonance energy transfer analysis of mRNA transcripts for highly sensitive gene expression profiling in near real time.

PubMed

Peng, Zhiyong; Young, Brandon; Baird, Alison E; Soper, Steven A

2013-08-20

Expression analysis of mRNAs transcribed from certain genes can be used as important sources of biomarkers for in vitro diagnostics. While the use of reverse transcription quantitative PCR (RT-qPCR) can provide excellent analytical sensitivity for monitoring transcript numbers, more sensitive approaches for expression analysis that can report results in near real-time are needed for many critical applications. We report a novel assay that can provide exquisite limits-of-quantitation and consists of reverse transcription (RT) followed by a ligase detection reaction (LDR) with single-pair fluorescence resonance energy transfer (spFRET) to provide digital readout through molecular counting. For this assay, no PCR was employed, which enabled short assay turnaround times. To facilitate implementation of the assay, a cyclic olefin copolymer (COC) microchip, which was fabricated using hot embossing, was employed to carry out the LDR in a continuous flow format with online single-molecule detection following the LDR. As demonstrators of the assay's utility, MMP-7 mRNA was expression profiled from several colorectal cancer cell lines. It was found that the RT-LDR/spFRET assay produced highly linear calibration plots even in the low copy number regime. Comparison to RT-qPCR indicated a better linearity over the low copy number range investigated (10-10,000 copies) with an R(2) = 0.9995 for RT-LDR/spFRET and R(2) = 0.98 for RT-qPCR. In addition, differentiating between copy numbers of 10 and 50 could be performed with higher confidence using RT-LDR/spFRET. To demonstrate the short assay turnaround times obtainable using the RT-LDR/spFRET assay, a two thermal cycle LDR was carried out on amphiphysin gene transcripts that can serve as important diagnostic markers for ischemic stroke. The ability to supply diagnostic information on possible stroke events in short turnaround times using RT-LDR/spFRET will enable clinicians to treat patients effectively with appropriate time-sensitive therapeutics.

Single-Pair Fret Analysis of mRNA Transcripts for Highly Sensitive Gene Expression Profiling in Near Real Time

PubMed Central

Peng, Zhiyong; Young, Brandon; Baird, Alison E.; Soper, Steven A.

2013-01-01

Expression analysis of mRNAs transcribed from certain genes can be used as important sources of biomarkers for in vitro diagnostics. While the use of reverse transcription quantitative PCR (RT-qPCR) can provide excellent analytical sensitivity for monitoring transcript numbers, more sensitive approaches for expression analysis that can report results in near real-time are needed for many critical applications. We report a novel assay that can provide exquisite limits-of-quantitation and consists of reverse transcription (RT) followed by a ligase detection reaction (LDR) with single-pair fluorescence resonance energy transfer (spFRET) to provide digital readout through molecular counting. For this assay, no PCR was employed, which enabled short assay turnaround times. To facilitate implementation of the assay, a cyclic olefin copolymer (COC) microchip, which was fabricated using hot embossing, was employed to carry out the LDR in a continuous flow format with on-line single-molecule detection following the LDR. As demonstrators of the assay's utility, MMP-7 mRNA was expression profiled from several colorectal cancer cell lines. It was found that the RT-LDR/spFRET assay produced highly linear calibration plots even in the low copy number regime. Comparison to RT-qPCR indicated a better linearity over the low copy number range investigated (10 − 10,000 copies) with an R2 = 0.9995 for RT-LDR/spFRET and R2 = 0.98 for RT-qPCR. In addition, differentiating between copy numbers of 10 and 50 could be performed with higher confidence using RT-LDR/spFRET. To demonstrate the short assay turnaround times obtainable using the RT-LDR/spFRET assay, a 2 thermal cycle LDR was carried out on amphiphysin gene transcripts that can serve as important diagnostic markers for ischemic stroke. The ability to supply diagnostic information on possible stroke events in short turnaround times using RT-LDR/spFRET will enable clinicians to treat patients effectively with appropriate time-sensitive therapeutics. PMID:23869556

Short- and long-term impact of critical illness on relatives: literature review.

PubMed

Paul, Fiona; Rattray, Janice

2008-05-01

This paper is a report of a literature review undertaken to identify the short- and long-term impact of critical illness on relatives. Patients in intensive care can experience physical and psychological consequences, and their relatives may also experience such effects. Although it is recognized that relatives have specific needs, it is not clear whether these needs are always met and whether further support is required, particularly after intensive care. The following databases were searched for the period 1950-2007: Medline, British Nursing Index and Archive, EMBASE, CINAHL, PsycINFO and EMB Reviews--Cochrane Central Register of Clinical Trials. Search terms focused on adult relatives of critically ill adult patients during and after intensive care. Recurrent topics were categorized to structure the review, i.e. 'relatives needs', 'meeting relatives' needs', 'interventions', 'satisfaction', 'psychological outcomes' and 'coping'. Studies have mainly identified relatives' immediate needs using the Critical Care Family Needs Inventory. There are few studies of interventions to meet relatives' needs and the short- and long-term effects of critical illness on relatives. Despite widespread use of the Critical Care Family Needs Inventory, factors such as local or cultural differences may influence relatives' needs. Relatives may also have unidentified needs, and these needs should be explored. Limited research has been carried out into interventions to meet relatives' needs and the effects of critical illness on their well-being, yet some relatives may experience negative psychological consequences far beyond the acute phase of the illness.

Safety Performance of Small Lithium-Ion Cells in High Voltage Batteries

NASA Technical Reports Server (NTRS)

Cowles, Philip R.; Darcy, Eric C.; Davies, Frank J.; Jeevarajan, Judith A.; Spurrett, Robert P.

2003-01-01

Topics covered include: Small-cell EAPU work done by NASA-JSC & COM DEV; Looking at safety features (short circuit protection - PTCs); Early tests showed that long strings do not withstand short circuit; a) Some PTCs experience large negative voltages; b) Destructive results. Solution: group cells into shorter substrings, with bypass diodes Work included: a) Tests with single cells shorted; b) Tests with single cells with imposed-negative voltages; c) 6s, 7s and 8s string shorts; and d) Tests with protection scheme in place, on 12s and 41s x 5p.

Critical current degradation behaviour of GdBCO CC tapes in pure torsion and combined tension-torsion modes

NASA Astrophysics Data System (ADS)

Gorospe, Alking; Bautista, Zhierwinjay; Shin, Hyung-Seop

2016-10-01

Coated conductor (CC) tapes utilized in high-current-density superconducting cables are commonly subjected to different loading modes, primarily torsion and tension especially in the case of twisted stacked-tape cable. Torsion load can occur due to twisting along the length or when winding the CC tapes around a former, while tension load can occur due to pre-tension when coiled and as a hoop stress when the coil is energized. In this study, electromechanical properties of single CC tapes under torsion load were investigated using a new test apparatus. The results could provide basic information for cable designers to fully characterize stacked cables. Copper-electroplated and brass-laminated CC tapes fabricated with different deposition techniques were subjected to pure torsion and combined tension-torsion loading. The critical current, I c degradation behaviours of CC tapes under torsional deformation were examined. Also, the effect of further external lamination on the I c degradation behaviour of the CC tapes under such loading conditions was investigated. In the case of the combined tension-torsion test, short samples were subjected to twist pitches of 200 mm and 100 mm. Critical parameters including reversible axial stress and strain in such twist pitch conditions were also investigated.

Coexistence in neutral theories: interplay of criticality and mild local preferences

NASA Astrophysics Data System (ADS)

Borile, Claudio; Molina-Garcia, Daniel; Maritan, Amos; Muñoz, Miguel A.

2015-01-01

Neutral theories have played a crucial and revolutionary role in fields such as population genetics and biogeography. These theories are critical by definition, in the sense that the overall growth rate of each single allele/species/type vanishes. Thus each species in a neutral model sits at the edge between invasion and extinction, allowing for the coexistence of symmetric/neutral types. However, in finite systems, mono-dominated states are ineluctably reached in relatively short times owing to demographic fluctuations, thus leaving us with an unsatisfactory framework to rationalize empirically-observed long-term coexistence. Here, we scrutinize the effect of heterogeneity in quasi-neutral theories, in which there can be a local mild preference for some of the competing species at some sites, even if the overall species symmetry is maintained. As we show here, mild biases at a small fraction of locations suffice to induce overall robust and durable species coexistence, even in regions arbitrarily far apart from the biased locations. This result stems from the long-range nature of the underlying critical bulk dynamics and has a number of implications, for example, in conservation ecology as it suggests that constructing local specific ‘sanctuaries’ for different competing species can result in global enhancement of biodiversity, even in regions arbitrarily distant from the protected refuges.

Short rotation forestry harvesting - systems and costs

Treesearch

Bruce R. Hartsough; Bryce J. Stokes

1997-01-01

Single stem short rotation plantations in the United States are largely dedicated to pulp production, with fuel as a secondary product. There are very limited plantings for fuel production, and others where the primary purpose is treatment of various wastewater's. All production harvesting of single stem plantations is conducted with conventional forestry...

Self-Channelling of a Short Laser Pulse at Relativistic Intensity in Near Critical Underdense Plasma

NASA Astrophysics Data System (ADS)

Willi, O.; Borghesi, M.; MacKinnon, A. J.; Barringer, L.; Gaillard, R.; Meyer, C.; Gizzi, L.; Pukhov, A.; Meyer-Ter-Vehn, J.

1996-11-01

Self channelling of a picosecond pulse at relativistic intensities has been observed in near critical underdense plasmas. The plasma was preformed by laser heating of a thin film. The interaction pulse (1-3 ps duration, 1.054 μm) was focused onto the plasma at irradiances above 5 × 10^18 W/cm^2. Self-channelling of the pulse was detected via second harmonic and optical probe measurements. Intense, localised 2ω emission suggests the formation of channel structures of less than 5 μm in diameter, extending for several Rayleigh lengths. The temporal evolution of the electron density profile across the channel was measured via interferometry with picosecond temporal resolution. PIC code simulations, performed for the conditions of the experiment, predict the formation of similar channel structures. In this model, in addition to relativistic and ponderomotive self-focusing mechanisms, pinching by large self-generated magnetic fields also contributes to the single channel formation. Measurements of magnetic fields were also performed that seem to be consistent with the computational model.

Responses of aquatic insects to Cu and Zn in stream microcosms: understanding differences between single species tests and field responses.

PubMed

Clements, William H; Cadmus, Pete; Brinkman, Stephen F

2013-07-02

Field surveys of metal-contaminated streams suggest that some aquatic insects, particularly mayflies (Ephemeroptera) and stoneflies (Plecoptera), are highly sensitive to metals. However, results of single species toxicity tests indicate these organisms are quite tolerant, with LC50 values often several orders of magnitude greater than those obtained using standard test organisms (e.g., cladocerans and fathead minnows). Reconciling these differences is a critical research need, particularly since water quality criteria for metals are based primarily on results of single species toxicity tests. In this research we provide evidence based on community-level microcosm experiments to support the hypothesis that some aquatic insects are highly sensitive to metals. We present results of three experiments that quantified effects of Cu and Zn, alone and in combination, on stream insect communities. EC50 values, defined as the metal concentration that reduced abundance of aquatic insects by 50%, were several orders of magnitude lower than previously published values obtained from single species tests. We hypothesize that the short duration of laboratory toxicity tests and the failure to evaluate effects of metals on sensitive early life stages are the primary factors responsible for unrealistically high LC50 values in the literature. We also observed that Cu alone was significantly more toxic to aquatic insects than the combination of Cu and Zn, despite the fact that exposure concentrations represented theoretically similar toxicity levels. Our results suggest that water quality criteria for Zn were protective of most aquatic insects, whereas Cu was highly toxic to some species at concentrations near water quality criteria. Because of the functional significance of aquatic insects in stream ecosystems and their well-established importance as indicators of water quality, reconciling differences between field and laboratory responses and understanding the mechanisms responsible for variation in sensitivity among metals and metal mixtures is of critical importance.

Postnatal Cardiac Gene Editing Using CRISPR/Cas9 With AAV9-Mediated Delivery of Short Guide RNAs Results in Mosaic Gene Disruption.

PubMed

Johansen, Anne Katrine; Molenaar, Bas; Versteeg, Danielle; Leitoguinho, Ana Rita; Demkes, Charlotte; Spanjaard, Bastiaan; de Ruiter, Hesther; Akbari Moqadam, Farhad; Kooijman, Lieneke; Zentilin, Lorena; Giacca, Mauro; van Rooij, Eva

2017-10-27

CRISPR/Cas9 (clustered regularly interspaced palindromic repeats/CRISPR-associated protein 9)-based DNA editing has rapidly evolved as an attractive tool to modify the genome. Although CRISPR/Cas9 has been extensively used to manipulate the germline in zygotes, its application in postnatal gene editing remains incompletely characterized. To evaluate the feasibility of CRISPR/Cas9-based cardiac genome editing in vivo in postnatal mice. We generated cardiomyocyte-specific Cas9 mice and demonstrated that Cas9 expression does not affect cardiac function or gene expression. As a proof-of-concept, we delivered short guide RNAs targeting 3 genes critical for cardiac physiology, Myh6 , Sav1 , and Tbx20 , using a cardiotropic adeno-associated viral vector 9. Despite a similar degree of DNA disruption and subsequent mRNA downregulation, only disruption of Myh6 was sufficient to induce a cardiac phenotype, irrespective of short guide RNA exposure or the level of Cas9 expression. DNA sequencing analysis revealed target-dependent mutations that were highly reproducible across mice resulting in differential rates of in- and out-of-frame mutations. Finally, we applied a dual short guide RNA approach to effectively delete an important coding region of Sav1 , which increased the editing efficiency. Our results indicate that the effect of postnatal CRISPR/Cas9-based cardiac gene editing using adeno-associated virus serotype 9 to deliver a single short guide RNA is target dependent. We demonstrate a mosaic pattern of gene disruption, which hinders the application of the technology to study gene function. Further studies are required to expand the versatility of CRISPR/Cas9 as a robust tool to study novel cardiac gene functions in vivo. © 2017 American Heart Association, Inc.

Half the entanglement in critical systems is distillable from a single specimen

NASA Astrophysics Data System (ADS)

Orús, R.; Latorre, J. I.; Eisert, J.; Cramer, M.

2006-06-01

We establish a quantitative relationship between the entanglement content of a single quantum chain at a critical point and the corresponding entropy of entanglement. We find that, surprisingly, the leading critical scaling of the single-copy entanglement with respect to any bipartitioning is exactly one-half of the entropy of entanglement, in a general setting of conformal field theory and quasifree systems. Conformal symmetry imposes that the single-copy entanglement scales as E1(ρL)=(c/6)lnL-(c/6)(π2/lnL)+O(1/L) , where L is the number of constituents in a block of an infinite chain and c denotes the central charge. This shows that from a single specimen of a critical chain, already half the entanglement can be distilled compared to the rate that is asymptotically available. The result is substantiated by a quantitative analysis for all translationally invariant quantum spin chains corresponding to all isotropic quasifree fermionic models. An example of the XY spin chain shows that away from criticality the above relation is maintained only near the quantum phase transition.

High-throughput single-molecule telomere characterization.

PubMed

McCaffrey, Jennifer; Young, Eleanor; Lassahn, Katy; Sibert, Justin; Pastor, Steven; Riethman, Harold; Xiao, Ming

2017-11-01

We have developed a novel method that enables global subtelomere and haplotype-resolved analysis of telomere lengths at the single-molecule level. An in vitro CRISPR/Cas9 RNA-directed nickase system directs the specific labeling of human (TTAGGG)n DNA tracts in genomes that have also been barcoded using a separate nickase enzyme that recognizes a 7-bp motif genome-wide. High-throughput imaging and analysis of large DNA single molecules from genomes labeled in this fashion using a nanochannel array system permits mapping through subtelomere repeat element (SRE) regions to unique chromosomal DNA while simultaneously measuring the (TTAGGG)n tract length at the end of each large telomere-terminal DNA segment. The methodology also permits subtelomere and haplotype-resolved analyses of SRE organization and variation, providing a window into the population dynamics and potential functions of these complex and structurally variant telomere-adjacent DNA regions. At its current stage of development, the assay can be used to identify and characterize telomere length distributions of 30-35 discrete telomeres simultaneously and accurately. The assay's utility is demonstrated using early versus late passage and senescent human diploid fibroblasts, documenting the anticipated telomere attrition on a global telomere-by-telomere basis as well as identifying subtelomere-specific biases for critically short telomeres. Similarly, we present the first global single-telomere-resolved analyses of two cancer cell lines. © 2017 McCaffrey et al.; Published by Cold Spring Harbor Laboratory Press.

Ballistic Graphene Josephson Junctions from the Short to the Long Junction Regimes.

PubMed

Borzenets, I V; Amet, F; Ke, C T; Draelos, A W; Wei, M T; Seredinski, A; Watanabe, K; Taniguchi, T; Bomze, Y; Yamamoto, M; Tarucha, S; Finkelstein, G

2016-12-02

We investigate the critical current I_{C} of ballistic Josephson junctions made of encapsulated graphene-boron-nitride heterostructures. We observe a crossover from the short to the long junction regimes as the length of the device increases. In long ballistic junctions, I_{C} is found to scale as ∝exp(-k_{B}T/δE). The extracted energies δE are independent of the carrier density and proportional to the level spacing of the ballistic cavity. As T→0 the critical current of a long (or short) junction saturates at a level determined by the product of δE (or Δ) and the number of the junction's transversal modes.

Characterization of the ITER CS conductor and projection to the ITER CS performance

DOE PAGES

Martovetsky, N.; Isono, T.; Bessette, D.; ...

2017-06-20

The ITER Central Solenoid (CS) is one of the critical elements of the machine. The CS conductor went through an intense optimization and qualification program, which included characterization of the strands, a conductor straight short sample testing in the SULTAN facility at the Swiss Plasma Center (SPC), Villigen, Switzerland, and a single-layer CS Insert coil recently tested in the Central Solenoid Model Coil (CSMC) facility in QST-Naka, Japan. In this paper, we obtained valuable data in a wide range of the parameters (current, magnetic field, temperature, and strain), which allowed a credible characterization of the CS conductor in different conditions.more » Finally, using this characterization, we will make a projection to the performance of the CS in the ITER reference scenario.« less

Characterization of the ITER CS conductor and projection to the ITER CS performance

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

Martovetsky, N.; Isono, T.; Bessette, D.

The ITER Central Solenoid (CS) is one of the critical elements of the machine. The CS conductor went through an intense optimization and qualification program, which included characterization of the strands, a conductor straight short sample testing in the SULTAN facility at the Swiss Plasma Center (SPC), Villigen, Switzerland, and a single-layer CS Insert coil recently tested in the Central Solenoid Model Coil (CSMC) facility in QST-Naka, Japan. In this paper, we obtained valuable data in a wide range of the parameters (current, magnetic field, temperature, and strain), which allowed a credible characterization of the CS conductor in different conditions.more » Finally, using this characterization, we will make a projection to the performance of the CS in the ITER reference scenario.« less

A 15-Step Synthesis of (+)-Ryanodol

PubMed Central

Chuang, Kangway V.; Xu, Chen; Reisman, Sarah E.

2017-01-01

(+)-Ryanodine and (+)-ryanodol are complex diterpenoids that modulate intracellular Ca2+ release at ryanodine receptors, ion channels critical for skeletal and cardiac muscle excitation–contraction coupling and synaptic transmission. Chemical derivatization of these diterpenoids has demonstrated that certain peripheral structural modifications can alter binding affinity and selectivity among ryanodine receptor isoforms. Here we report a short chemical synthesis of (+)-ryanodol that proceeds in only 15 steps from the commercially available terpene (S)-pulegone. The efficiency of the synthesis derives from the use of a Pauson-Khand reaction to rapidly build the carbon framework, and a remarkable SeO2-mediated oxidation to install three oxygen atoms in single step. This work highlights how strategic C–O bond constructions can streamline the synthesis of poly-hydroxylated terpenes by minimizing protecting group and redox adjustments. PMID:27563092

Many-body delocalization with random vector potentials

NASA Astrophysics Data System (ADS)

Cheng, Chen; Mondaini, Rubem

2016-11-01

We study the ergodic properties of excited states in a model of interacting fermions in quasi-one-dimensional chains subjected to a random vector potential. In the noninteracting limit, we show that arbitrarily small values of this complex off-diagonal disorder trigger localization for the whole spectrum; the divergence of the localization length in the single-particle basis is characterized by a critical exponent ν which depends on the energy density being investigated. When short-range interactions are included, the localization is lost, and the system is ergodic regardless of the magnitude of disorder in finite chains. Our numerical results suggest a delocalization scheme for arbitrary small values of interactions. This finding indicates that the standard scenario of the many-body localization cannot be obtained in a model with random gauge fields.

Comparison of Interferometric Time-Series Analysis Techniques with Implications for Future Mission Design

NASA Astrophysics Data System (ADS)

Werner, C. L.; Wegmuller, U.; Strozzi, T.; Wiesmann, A.

2006-12-01

Principle contributors to the noise in differential SAR interferograms are temporal phase stability of the surface, geometry relating to baseline and surface slope, and propagation path delay variations due to tropospheric water vapor and the ionosphere. Time series analysis of multiple interferograms generated from a stack of SAR SLC images seeks to determine the deformation history of the surface while reducing errors. Only those scatterers within a resolution element that are stable and coherent for each interferometric pair contribute to the desired deformation signal. Interferograms with baselines exceeding 1/3 the critical baseline have substantial geometrical decorrelation for distributed targets. Short baseline pairs with multiple reference scenes can be combined using least-squares estimation to obtain a global deformation solution. Alternately point-like persistent scatterers can be identified in scenes that do not exhibit geometrical decorrelation associated with large baselines. In this approach interferograms are formed from a stack of SAR complex images using a single reference scene. Stable distributed scatter pixels are excluded however due to the presence of large baselines. We apply both point- based and short-baseline methodologies and compare results for a stack of fine-beam Radarsat data acquired in 2002-2004 over a rapidly subsiding oil field near Lost Hills, CA. We also investigate the density of point-like scatters with respect to image resolution. The primary difficulty encountered when applying time series methods is phase unwrapping errors due to spatial and temporal gaps. Phase unwrapping requires sufficient spatial and temporal sampling. Increasing the SAR range bandwidth increases the range resolution as well as increasing the critical interferometric baseline that defines the required satellite orbital tube diameter. Sufficient spatial sampling also permits unwrapping because of the reduced phase/pixel gradient. Short time intervals further reduce the differential phase due to deformation when the deformation is continuous. Lower frequency systems (L- vs. C-Band) substantially improve the ability to unwrap the phase correctly by directly reducing both interferometric phase amplitude and temporal decorrelation.

Three-dimensional magnetic critical behavior in CrI 3

DOE PAGES

Liu, Yu; Petrovic, C.

2018-01-18

CrI 3 is a promising candidate for the van der Waals bonded ferromagnetic devices since its ferromagnetism can be maintained upon exfoliating of bulk crystals down to single layer. In this work we studied critical properties of bulk CrI 3 single crystals around the paramagnetic to ferromagnetic phase transition. Critical exponents β= 0.260(4) with a critical temperature T c= 60.05(13) K and γ= 1.136(6) with T c= 60.43(4) K are obtained by the Kouvel-Fisher method, whereas δ= 5.32(2) is obtained by a critical isotherm analysis at T c= 60 K. In conclusion, the critical exponents determined in bulk CrI 3more » single crystals suggest a three-dimensional long-range magnetic coupling with the exchange distance decaying as J(r)≈r -4:69« less

Solving the Mystery of the Short-Hard Gamma-Ray Bursts

NASA Astrophysics Data System (ADS)

Fox, Derek

2004-07-01

Seven years after the afterglow detections that revolutionized studies of the long-soft gamma-ray bursts, not even one afterglow of a short-hard GRB has been seen, and the nature of these events has become one of the most important problems in GRB research. The forthcoming Swift satellite will report few-arcsecond localizations for short-hard bursts in minutes, however, enabling prompt, deep optical afterglow searches for the first time. Discovery and observation of the first short-hard optical afterglows will answer most of the critical questions about these events: What are their distances and energies? Do they occur in distant galaxies, and if so, in which regions of those galaxies? Are they the result of collimated or quasi-spherical explosions? In combination with an extensive rapid-response ground-based campaign, we propose to make the critical high-sensitivity HST TOO observations that will allow us to answer these questions. If theorists are correct in attributing the short-hard bursts to binary neutron star coalescence events, then the short-hard bursts are signposts to the primary targeted source population for ground-based gravitational-wave detectors, and short-hard burst studies will have a vital role to play in guiding their observations.

Single-virion sequencing of lamivudine-treated HBV populations reveal population evolution dynamics and demographic history.

PubMed

Zhu, Yuan O; Aw, Pauline P K; de Sessions, Paola Florez; Hong, Shuzhen; See, Lee Xian; Hong, Lewis Z; Wilm, Andreas; Li, Chen Hao; Hue, Stephane; Lim, Seng Gee; Nagarajan, Niranjan; Burkholder, William F; Hibberd, Martin

2017-10-27

Viral populations are complex, dynamic, and fast evolving. The evolution of groups of closely related viruses in a competitive environment is termed quasispecies. To fully understand the role that quasispecies play in viral evolution, characterizing the trajectories of viral genotypes in an evolving population is the key. In particular, long-range haplotype information for thousands of individual viruses is critical; yet generating this information is non-trivial. Popular deep sequencing methods generate relatively short reads that do not preserve linkage information, while third generation sequencing methods have higher error rates that make detection of low frequency mutations a bioinformatics challenge. Here we applied BAsE-Seq, an Illumina-based single-virion sequencing technology, to eight samples from four chronic hepatitis B (CHB) patients - once before antiviral treatment and once after viral rebound due to resistance. With single-virion sequencing, we obtained 248-8796 single-virion sequences per sample, which allowed us to find evidence for both hard and soft selective sweeps. We were able to reconstruct population demographic history that was independently verified by clinically collected data. We further verified four of the samples independently through PacBio SMRT and Illumina Pooled deep sequencing. Overall, we showed that single-virion sequencing yields insight into viral evolution and population dynamics in an efficient and high throughput manner. We believe that single-virion sequencing is widely applicable to the study of viral evolution in the context of drug resistance and host adaptation, allows differentiation between soft or hard selective sweeps, and may be useful in the reconstruction of intra-host viral population demographic history.

Testing effects in visual short-term memory: The case of an object's size.

PubMed

Makovski, Tal

2018-05-29

In many daily activities, we need to form and retain temporary representations of an object's size. Typically, such visual short-term memory (VSTM) representations follow perception and are considered reliable. Here, participants were asked to hold in mind a single simple object for a short duration and to reproduce its size by adjusting the length and width of a test probe. Experiment 1 revealed two powerful findings: First, similar to a recently reported perceptual illusion, participants greatly overestimated the size of open objects - ones with missing boundaries - relative to the same-size fully closed objects. This finding confirms that object boundaries are critical for size perception and memory. Second, and in contrast to perception, even the size of the closed objects was largely overestimated. Both inflation effects were substantial and were replicated and extended in Experiments 2-5. Experiments 6-8 used a different testing procedure to examine whether the overestimation effects are due to inflation of size in VSTM representations or to biases introduced during the reproduction phase. These data showed that while the overestimation of the open objects was repeated, the overestimation of the closed objects was not. Taken together, these findings suggest that similar to perception, only the size representation of open objects is inflated in VSTM. Importantly, they demonstrate the considerable impact of the testing procedure on VSTM tasks and further question the use of reproduction procedures for measuring VSTM.

Measurement of fatigue: Comparison of the reliability and validity of single-item and short measures to a comprehensive measure.

PubMed

Kim, Hee-Ju; Abraham, Ivo

2017-01-01

Evidence is needed on the clinicometric properties of single-item or short measures as alternatives to comprehensive measures. We examined whether two single-item fatigue measures (i.e., Likert scale, numeric rating scale) or a short fatigue measure were comparable to a comprehensive measure in reliability (i.e., internal consistency and test-retest reliability) and validity (i.e., convergent, concurrent, and predictive validity) in Korean young adults. For this quantitative study, we selected the Functional Assessment of Chronic Illness Therapy-Fatigue for the comprehensive measure and the Profile of Mood States-Brief, Fatigue subscale for the short measure; and constructed two single-item measures. A total of 368 students from four nursing colleges in South Korea participated. We used Cronbach's alpha and item-total correlation for internal consistency reliability and intraclass correlation coefficient for test-retest reliability. We assessed Pearson's correlation with a comprehensive measure for convergent validity, with perceived stress level and sleep quality for concurrent validity and the receiver operating characteristic curve for predictive validity. The short measure was comparable to the comprehensive measure in internal consistency reliability (Cronbach's alpha=0.81 vs. 0.88); test-retest reliability (intraclass correlation coefficient=0.66 vs. 0.61); convergent validity (r with comprehensive measure=0.79); concurrent validity (r with perceived stress=0.55, r with sleep quality=0.39) and predictive validity (area under curve=0.88). Single-item measures were not comparable to the comprehensive measure. A short fatigue measure exhibited similar levels of reliability and validity to the comprehensive measure in Korean young adults. Copyright © 2016 Elsevier Ltd. All rights reserved.

Comparison of Critical Thinking in Undergraduates and Graduates in Special Education

ERIC Educational Resources Information Center

Zascavage, Victoria; Masten, William G.; Schroeder-Steward, Jennifer; Nichols, Christopher

2007-01-01

This study assessed overall critical thinking ability in graduate and undergraduate students in special education at a southwestern university. A comparison of the two groups resulted in significant differences on the Watson-Glaser Critical Thinking Appraisal Form Short (WGCTA-FS) subscales for Inference, Recognition of Assumption, Deduction, and…

Integrating Levels of Critical Thinking into Writing Assignments for Introductory Psychology Students.

ERIC Educational Resources Information Center

Willis, A. Sandra

Short analytical writing exercises were designed to develop critical thinking and writing skills; stimulate creative thinking and writing; promote learning of psychological concepts; and to assess student knowledge. Design of these assignments was based on Bloom's taxonomy of multiple levels of critical thinking: recall, comprehension,…

Using Self-Experimentation and Single-Subject Methodology to Promote Critical Thinking

ERIC Educational Resources Information Center

Cowley, Brian J.; Lindgren, Ann; Langdon, David

2006-01-01

Critical thinking is often absent from classroom endeavor because it is hard to define (Gelder, 2005) or is difficult to assess (Bissell & Lemons, 2006). Critical thinking is defined as application, analysis, synthesis, and evaluation (Browne & Minnick, 2005). This paper shows how self-experimentation and single-subject methodology can be used to…

Fast two-photon imaging of subcellular voltage dynamics in neuronal tissue with genetically encoded indicators

PubMed Central

Chamberland, Simon; Yang, Helen H; Pan, Michael M; Evans, Stephen W; Guan, Sihui; Chavarha, Mariya; Yang, Ying; Salesse, Charleen; Wu, Haodi; Wu, Joseph C; Clandinin, Thomas R; Toth, Katalin; Lin, Michael Z; St-Pierre, François

2017-01-01

Monitoring voltage dynamics in defined neurons deep in the brain is critical for unraveling the function of neuronal circuits but is challenging due to the limited performance of existing tools. In particular, while genetically encoded voltage indicators have shown promise for optical detection of voltage transients, many indicators exhibit low sensitivity when imaged under two-photon illumination. Previous studies thus fell short of visualizing voltage dynamics in individual neurons in single trials. Here, we report ASAP2s, a novel voltage indicator with improved sensitivity. By imaging ASAP2s using random-access multi-photon microscopy, we demonstrate robust single-trial detection of action potentials in organotypic slice cultures. We also show that ASAP2s enables two-photon imaging of graded potentials in organotypic slice cultures and in Drosophila. These results demonstrate that the combination of ASAP2s and fast two-photon imaging methods enables detection of neural electrical activity with subcellular spatial resolution and millisecond-timescale precision. DOI: http://dx.doi.org/10.7554/eLife.25690.001 PMID:28749338

How to understand atomistic molecular dynamics simulations of RNA and protein-RNA complexes?

PubMed

Šponer, Jiří; Krepl, Miroslav; Banáš, Pavel; Kührová, Petra; Zgarbová, Marie; Jurečka, Petr; Havrila, Marek; Otyepka, Michal

2017-05-01

We provide a critical assessment of explicit-solvent atomistic molecular dynamics (MD) simulations of RNA and protein/RNA complexes, written primarily for non-specialists with an emphasis to explain the limitations of MD. MD simulations can be likened to hypothetical single-molecule experiments starting from single atomistic conformations and investigating genuine thermal sampling of the biomolecules. The main advantage of MD is the unlimited temporal and spatial resolution of positions of all atoms in the simulated systems. Fundamental limitations are the short physical time-scale of simulations, which can be partially alleviated by enhanced-sampling techniques, and the highly approximate atomistic force fields describing the simulated molecules. The applicability and present limitations of MD are demonstrated on studies of tetranucleotides, tetraloops, ribozymes, riboswitches and protein/RNA complexes. Wisely applied simulations respecting the approximations of the model can successfully complement structural and biochemical experiments. WIREs RNA 2017, 8:e1405. doi: 10.1002/wrna.1405 For further resources related to this article, please visit the WIREs website. © 2016 Wiley Periodicals, Inc.

Experimental and numerical simulation of a rotor/stator interaction event localized on a single blade within an industrial high-pressure compressor

NASA Astrophysics Data System (ADS)

Batailly, Alain; Agrapart, Quentin; Millecamps, Antoine; Brunel, Jean-François

2016-08-01

This contribution addresses a confrontation between the experimental simulation of a rotor/stator interaction case initiated by structural contacts with numerical predictions made with an in-house numerical strategy. Contrary to previous studies carried out within the low-pressure compressor of an aircraft engine, this interaction is found to be non-divergent: high amplitudes of vibration are experimentally observed and numerically predicted over a short period of time. An in-depth analysis of experimental data first allows for a precise characterization of the interaction as a rubbing event involving the first torsional mode of a single blade. Numerical results are in good agreement with experimental observations: the critical angular speed, the wear patterns on the casing as well as the blade dynamics are accurately predicted. Through out the article, the in-house numerical strategy is also confronted to another numerical strategy that may be found in the literature for the simulation of rubbing events: key differences are underlined with respect to the prediction of non-linear interaction phenomena.

Electromigration resistance in a short three-contact interconnect tree

NASA Astrophysics Data System (ADS)

Chang, C. W.; Choi, Z.-S.; Thompson, C. V.; Gan, C. L.; Pey, K. L.; Choi, W. K.; Hwang, N.

2006-05-01

Electromigration has been characterized in via-terminated interconnect lines with additional vias in the middle, creating two adjacent segments that can be stressed independently. The mortality of a segment was found to depend on the direction and magnitude of the current in the adjacent segment, confirming that there is not a fixed value of the product of the current density and segment length, jL, that defines immortality in individual segments that are part of a multisegment interconnect tree. Instead, it is found that the probability of failure of a multisegment tree increases with the increasing value of an effective jL product defined in earlier work. However, contrary to expectations, the failures were still observed when (jL)eff was less than the critical jL product for which lines were found to be immortal in single-segment test structures. It is argued that this is due to reservoir effects associated with unstressed segments or due to liner failure at the central via. Multisegment test structures are therefore shown to reveal more types of failure mechanisms and mortality conditions that are not found in tests with single-segment structures.

The stimulated Brillouin scattering during the interaction of picosecond laser pulses with moderate- scale-length plasmas

NASA Astrophysics Data System (ADS)

Gaeris, Andres Claudio

The Stimulated Brillouin Scattering (SBS) instability is studied in moderately short scale-length plasmas. The backscattered and specularly reflected light resulting from the interaction of a pair of high power picosecond duration laser pulses with solid Silicon, Gold and Parylene-N (CH) strip targets was spectrally resolved. The first, weaker laser pulse forms a short scale-length plasma while the second delayed one interacts with the isothermally expanded, underdense region of the plasma. The pulses are generated by the Table Top Terawatt (TTT) laser operating at 1054 nm (infrared) with intensities up to 5.10 16 W/cm2. Single laser pulses only show Lambertian scattering on the target critical surface. Pairs of pulses with high intensity in the second pulse show an additional backscattered, highly blueshifted feature, associated with SBS. Increasing this second pulse intensity even more leads to the appearance of a third feature, even more blueshifted than the second, resulting from the Brillouin sidescattering of the laser pulse reflected on the critical surface. The SBS threshold intensities and enhanced reflectivities for P-polarized light are determined for different plasma density scale-lengths. These measurements agree with the convective thresholds predicted by the SBS theory of Liu, Rosenbluth, and White using plasma profiles simulated by the LILAC code. The spectral position of the Brillouin back- and sidescattered features are determined. The SBS and Doppler shifts are much too small to explain the observed blueshifts. The refractive index shift is of the right magnitude, although more detailed verification is required in the future.

Assessing public speaking fear with the short form of the Personal Report of Confidence as a Speaker scale: confirmatory factor analyses among a French-speaking community sample.

PubMed

Heeren, Alexandre; Ceschi, Grazia; Valentiner, David P; Dethier, Vincent; Philippot, Pierre

2013-01-01

The main aim of this study was to assess the reliability and structural validity of the French version of the 12-item version of the Personal Report of Confidence as Speaker (PRCS), one of the most promising measurements of public speaking fear. A total of 611 French-speaking volunteers were administered the French versions of the short PRCS, the Liebowitz Social Anxiety Scale, the Fear of Negative Evaluation scale, as well as the Trait version of the Spielberger State-Trait Anxiety Inventory and the Beck Depression Inventory-II, which assess the level of anxious and depressive symptoms, respectively. Regarding its structural validity, confirmatory factor analyses indicated a single-factor solution, as implied by the original version. Good scale reliability (Cronbach's alpha = 0.86) was observed. The item discrimination analysis suggested that all the items contribute to the overall scale score reliability. The French version of the short PRCS showed significant correlations with the Liebowitz Social Anxiety Scale (r = 0.522), the Fear of Negative Evaluation scale (r = 0.414), the Spielberger State-Trait Anxiety Inventory (r = 0.516), and the Beck Depression Inventory-II (r = 0.361). The French version of the short PRCS is a reliable and valid measure for the evaluation of the fear of public speaking among a French-speaking sample. These findings have critical consequences for the measurement of psychological and pharmacological treatment effectiveness in public speaking fear among a French-speaking sample.

Assessing public speaking fear with the short form of the Personal Report of Confidence as a Speaker scale: confirmatory factor analyses among a French-speaking community sample

PubMed Central

Heeren, Alexandre; Ceschi, Grazia; Valentiner, David P; Dethier, Vincent; Philippot, Pierre

2013-01-01

Background: The main aim of this study was to assess the reliability and structural validity of the French version of the 12-item version of the Personal Report of Confidence as Speaker (PRCS), one of the most promising measurements of public speaking fear. Methods: A total of 611 French-speaking volunteers were administered the French versions of the short PRCS, the Liebowitz Social Anxiety Scale, the Fear of Negative Evaluation scale, as well as the Trait version of the Spielberger State-Trait Anxiety Inventory and the Beck Depression Inventory-II, which assess the level of anxious and depressive symptoms, respectively. Results: Regarding its structural validity, confirmatory factor analyses indicated a single-factor solution, as implied by the original version. Good scale reliability (Cronbach’s alpha = 0.86) was observed. The item discrimination analysis suggested that all the items contribute to the overall scale score reliability. The French version of the short PRCS showed significant correlations with the Liebowitz Social Anxiety Scale (r = 0.522), the Fear of Negative Evaluation scale (r = 0.414), the Spielberger State-Trait Anxiety Inventory (r = 0.516), and the Beck Depression Inventory-II (r = 0.361). Conclusion: The French version of the short PRCS is a reliable and valid measure for the evaluation of the fear of public speaking among a French-speaking sample. These findings have critical consequences for the measurement of psychological and pharmacological treatment effectiveness in public speaking fear among a French-speaking sample. PMID:23662060

The construction of general basis functions in reweighting ensemble dynamics simulations: Reproduce equilibrium distribution in complex systems from multiple short simulation trajectories

NASA Astrophysics Data System (ADS)

Zhang, Chuan-Biao; Ming, Li; Xin, Zhou

2015-12-01

Ensemble simulations, which use multiple short independent trajectories from dispersive initial conformations, rather than a single long trajectory as used in traditional simulations, are expected to sample complex systems such as biomolecules much more efficiently. The re-weighted ensemble dynamics (RED) is designed to combine these short trajectories to reconstruct the global equilibrium distribution. In the RED, a number of conformational functions, named as basis functions, are applied to relate these trajectories to each other, then a detailed-balance-based linear equation is built, whose solution provides the weights of these trajectories in equilibrium distribution. Thus, the sufficient and efficient selection of basis functions is critical to the practical application of RED. Here, we review and present a few possible ways to generally construct basis functions for applying the RED in complex molecular systems. Especially, for systems with less priori knowledge, we could generally use the root mean squared deviation (RMSD) among conformations to split the whole conformational space into a set of cells, then use the RMSD-based-cell functions as basis functions. We demonstrate the application of the RED in typical systems, including a two-dimensional toy model, the lattice Potts model, and a short peptide system. The results indicate that the RED with the constructions of basis functions not only more efficiently sample the complex systems, but also provide a general way to understand the metastable structure of conformational space. Project supported by the National Natural Science Foundation of China (Grant No. 11175250).

Computational and experimental analysis of short peptide motifs for enzyme inhibition.

PubMed

Fu, Jinglin; Larini, Luca; Cooper, Anthony J; Whittaker, John W; Ahmed, Azka; Dong, Junhao; Lee, Minyoung; Zhang, Ting

2017-01-01

The metabolism of living systems involves many enzymes that play key roles as catalysts and are essential to biological function. Searching ligands with the ability to modulate enzyme activities is central to diagnosis and therapeutics. Peptides represent a promising class of potential enzyme modulators due to the large chemical diversity, and well-established methods for library synthesis. Peptides and their derivatives are found to play critical roles in modulating enzymes and mediating cellular uptakes, which are increasingly valuable in therapeutics. We present a methodology that uses molecular dynamics (MD) and point-variant screening to identify short peptide motifs that are critical for inhibiting β-galactosidase (β-Gal). MD was used to simulate the conformations of peptides and to suggest short motifs that were most populated in simulated conformations. The function of the simulated motifs was further validated by the experimental point-variant screening as critical segments for inhibiting the enzyme. Based on the validated motifs, we eventually identified a 7-mer short peptide for inhibiting an enzyme with low μM IC50. The advantage of our methodology is the relatively simplified simulation that is informative enough to identify the critical sequence of a peptide inhibitor, with a precision comparable to truncation and alanine scanning experiments. Our combined experimental and computational approach does not rely on a detailed understanding of mechanistic and structural details. The MD simulation suggests the populated motifs that are consistent with the results of the experimental alanine and truncation scanning. This approach appears to be applicable to both natural and artificial peptides. With more discovered short motifs in the future, they could be exploited for modulating biocatalysis, and developing new medicine.

Telomerase and Tel1p Preferentially Associate with Short Telomeres in S. cerevisiae

PubMed Central

Sabourin, Michelle; Tuzon, Creighton T.; Zakian, Virginia A.

2009-01-01

SUMMARY In diverse organisms, telomerase preferentially elongates short telomeres. We generated a single short telomere in otherwise wild-type (WT) S. cerevisiae cells. The binding of the positive regulators Ku and Cdc13p was similar at short and WT-length telomeres. The negative regulators Rif1p and Rif2p were present at the short telomere, although Rif2p levels were reduced. Two telomerase holoenzyme components, Est1p and Est2p, were preferentially enriched at short telomeres in late S/G2 phase, the time of telomerase action. Tel1p, the yeast ATM-like checkpoint kinase, was highly enriched at short telomeres from early S through G2 phase and even into the next cell cycle. Nonetheless, induction of a single short telomere did not elicit a cell-cycle arrest. Tel1p binding was dependent on Xrs2p and required for preferential binding of telomerase to short telomeres. These data suggest that Tel1p targets telomerase to the DNA ends most in need of extension. PMID:17656141

Chiral photonic crystal fibers with single mode and single polarization

NASA Astrophysics Data System (ADS)

Li, She; Li, Junqing

2015-12-01

Chiral photonic crystal fiber (PCF) with a solid core is numerically investigated by a modified chiral plane-wave expansion method. The effects of structural parameters and chirality strength are analyzed on single-polarization single-mode range and polarization states of guided modes. The simulation demonstrates that the chiral photonic crystal fiber compared to its achiral counterpart possesses another single-circular-polarization operation range, which is located in the short-wavelength region. The original single-polarization operation range in the long-wavelength region extends to the short wavelength caused by introducing chirality. Then this range becomes a broadened one with elliptical polarization from linear polarization. With increase of chirality, the two single-polarization single-mode ranges may fuse together. By optimizing the structure, an ultra-wide single-circular-polarization operation range from 0.5 μm to 1.67 μm for chiral PCF can be realized with moderate chirality strength.

Short-term ensemble streamflow forecasting using operationally-produced single-valued streamflow forecasts - A Hydrologic Model Output Statistics (HMOS) approach

NASA Astrophysics Data System (ADS)

Regonda, Satish Kumar; Seo, Dong-Jun; Lawrence, Bill; Brown, James D.; Demargne, Julie

2013-08-01

We present a statistical procedure for generating short-term ensemble streamflow forecasts from single-valued, or deterministic, streamflow forecasts produced operationally by the U.S. National Weather Service (NWS) River Forecast Centers (RFCs). The resulting ensemble streamflow forecast provides an estimate of the predictive uncertainty associated with the single-valued forecast to support risk-based decision making by the forecasters and by the users of the forecast products, such as emergency managers. Forced by single-valued quantitative precipitation and temperature forecasts (QPF, QTF), the single-valued streamflow forecasts are produced at a 6-h time step nominally out to 5 days into the future. The single-valued streamflow forecasts reflect various run-time modifications, or "manual data assimilation", applied by the human forecasters in an attempt to reduce error from various sources in the end-to-end forecast process. The proposed procedure generates ensemble traces of streamflow from a parsimonious approximation of the conditional multivariate probability distribution of future streamflow given the single-valued streamflow forecast, QPF, and the most recent streamflow observation. For parameter estimation and evaluation, we used a multiyear archive of the single-valued river stage forecast produced operationally by the NWS Arkansas-Red River Basin River Forecast Center (ABRFC) in Tulsa, Oklahoma. As a by-product of parameter estimation, the procedure provides a categorical assessment of the effective lead time of the operational hydrologic forecasts for different QPF and forecast flow conditions. To evaluate the procedure, we carried out hindcasting experiments in dependent and cross-validation modes. The results indicate that the short-term streamflow ensemble hindcasts generated from the procedure are generally reliable within the effective lead time of the single-valued forecasts and well capture the skill of the single-valued forecasts. For smaller basins, however, the effective lead time is significantly reduced by short basin memory and reduced skill in the single-valued QPF.

Other origins for the fluorescence modulation of single dye molecules in open-circuit and short-circuit devices.

PubMed

Teguh, Jefri S; Kurniawan, Michael; Wu, Xiangyang; Sum, Tze Chien; Yeow, Edwin K L

2013-01-07

Fluorescence intensity modulation of single Atto647N dye molecules in a short-circuit device and a defective device, caused by damaging an open-circuit device, is due to a variation in the excitation light focus as a result of the formation of an alternating electric current.

Experimental Study of Thermal Field Evolution in the Short-Impending Stage Before Earthquakes

NASA Astrophysics Data System (ADS)

Ren, Yaqiong; Ma, Jin; Liu, Peixun; Chen, Shunyun

2017-08-01

Phenomena at critical points are vital for identifying the short-impending stage prior to earthquakes. The peak stress is a critical point when stress is converted from predominantly accumulation to predominantly release. We call the duration between the peak stress and instability "the meta-instability stage", which refers to the short-impending stage of earthquakes. The meta-instability stage consists of a steady releasing quasi-static stage and an accelerated releasing quasi-dynamic stage. The turning point of the above two stages is the remaining critical point. To identify the two critical points in the field, it is necessary to study the characteristic phenomena of various physical fields in the meta-instability stage in the laboratory, and the strain and displacement variations were studied. Considering that stress and relative displacement can be detected by thermal variations and peculiarities in the full-field observations, we employed a cooled thermal infrared imaging system to record thermal variations in the meta-instability stage of stick slip events generated along a simulated, precut planer strike slip fault in a granodiorite block on a horizontally bilateral servo-controlled press machine. The experimental results demonstrate the following: (1) a large area of decreasing temperatures in wall rocks and increasing temperatures in sporadic sections of the fault indicate entrance into the meta-instability stage. (2) The rapid expansion of regions of increasing temperatures on the fault and the enhancement of temperature increase amplitude correspond to the turning point from the quasi-static stage to the quasi-dynamic stage. Our results reveal thermal indicators for the critical points prior to earthquakes that provide clues for identifying the short-impending stage of earthquakes.

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

Liu, Yu; Petrovic, C.

CrI 3 is a promising candidate for the van der Waals bonded ferromagnetic devices since its ferromagnetism can be maintained upon exfoliating of bulk crystals down to single layer. In this work we studied critical properties of bulk CrI 3 single crystals around the paramagnetic to ferromagnetic phase transition. Critical exponents β= 0.260(4) with a critical temperature T c= 60.05(13) K and γ= 1.136(6) with T c= 60.43(4) K are obtained by the Kouvel-Fisher method, whereas δ= 5.32(2) is obtained by a critical isotherm analysis at T c= 60 K. In conclusion, the critical exponents determined in bulk CrI 3more » single crystals suggest a three-dimensional long-range magnetic coupling with the exchange distance decaying as J(r)≈r -4:69« less

Capacity building for critical care training delivery: Development and evaluation of the Network for Improving Critical care Skills Training (NICST) programme in Sri Lanka.

PubMed

Stephens, Tim; De Silva, A Pubudu; Beane, Abi; Welch, John; Sigera, Chathurani; De Alwis, Sunil; Athapattu, Priyantha; Dharmagunawardene, Dilantha; Peiris, Lalitha; Siriwardana, Somalatha; Abeynayaka, Ashoka; Jayasinghe, Kosala Saroj Amarasena; Mahipala, Palitha G; Dondorp, Arjen; Haniffa, Rashan

2017-04-01

To deliver and evaluate a short critical care nurse training course whilst simultaneously building local training capacity. A multi-modal short course for critical care nursing skills was delivered in seven training blocks, from 06/2013-11/2014. Each training block included a Train the Trainer programme. The project was evaluated using Kirkpatrick's Hierarchy of Learning. There was a graded hand over of responsibility for course delivery from overseas to local faculty between 2013 and 2014. Sri Lanka. Participant learning assessed through pre/post course Multi-Choice Questionnaires. A total of 584 nurses and 29 faculty were trained. Participant feedback was consistently positive and each course demonstrated a significant increase (p≤0.0001) in MCQ scores. There was no significant difference MCQ scores (p=0.186) between overseas faculty led and local faculty led courses. In a relatively short period, training with good educational outcomes was delivered to nearly 25% of the critical care nursing population in Sri Lanka whilst simultaneously building a local faculty of trainers. Through use of a structured Train the Trainer programme, course outcomes were maintained following the handover of training responsibility to Sri Lankan faculty. The focus on local capacity building increases the possibility of long term course sustainability. Copyright © 2016 Elsevier Ltd. All rights reserved.

Willa Cather as Drama Critic.

ERIC Educational Resources Information Center

Jensen, Marvin D.

Although Willa Cather is known primarily for her short fiction and novels, she began her writing career as a literary and drama critic while still a student at the University of Nebraska. Her writing experience with the university literary periodical led her to become the drama critic for the "Nebraska State Journal," and later for the…

A Critical Policy Analysis of Texas' "Closing the Gaps 2015"

ERIC Educational Resources Information Center

Mansfield, Katherine Cumings; Thackik, Stefani Leigh

2016-01-01

This critical policy analysis uses critical race theory to provide a counter narrative to the P-16 initiative in Texas known as "Closing the Gaps 2015". Findings indicate that while these reforms aim to increase educational access and achievement for people of color, they fall short of addressing systemic inequities such as enduring…

Stretching, twisting and supercoiling in short, single DNA molecules

NASA Astrophysics Data System (ADS)

Lam, Pui-Man; Zhen, Yi

2018-02-01

We had combined the Neukirch-Marko model that describes the extension, torque and supercoiling in single, stretched and twisted DNA of infinite contour length, with a form of the free energy suggested by Sinha and Samuels to describe short DNA, with contour length only a few times the persistence length. We find that the free energy of the stretched but untwisted DNA, is significantly modified from its infinitely length value and this in turn modifies significantly the torque and supercoiling. We show that this is consistent with short DNA being more flexible than infinitely long DNA. We hope our results will stimulate experimental investigation of torque and supercoiling in short DNA.

A Passage into Critical Theory.

ERIC Educational Resources Information Center

Lynn, Steven

1990-01-01

Shows how a single passage might be handled by New Criticism, structuralism, deconstructionism, psychological criticism, and feminist criticism. Concludes that a plurality of critical approaches is better than a unity of approach. (RS)

Comparative Short-Term Clinical Outcomes of Mediastinum Tumor Excision Performed by Conventional VATS and Single-Port VATS: Is It Worthwhile?

PubMed

Wu, Ching-Feng; Gonzalez-Rivas, Diego; Wen, Chih-Tsung; Liu, Yun-Hen; Wu, Yi-Cheng; Chao, Yin-Kai; Hsieh, Ming-Ju; Wu, Ching-Yang; Chen, Wei-Hsun

2015-11-01

Single-port video-assisted thoracoscopic surgery (VATS) has been widely applied recently. However, there are still only few reports describing its use in mediastinum tumor resection. We present the technique of single-port video-assisted thoracoscopic mediastinum tumor resection and compare it with conventional VATS with regard to short-term outcome.We retrospectively enrolled 105 patients who received mediastinum surgery in Chang Gung Memorial Hospital. Sixteen patients received sternotomy or thoracotomy, 29 patients received single-port VATS, and 60 patients received conventional VATS (3 ports). The operative time, blood loss, postoperation day 1 pain score, discharge day pain score, and postoperative hospital stay were compared. In order to establish a well balanced cohort study, we also use propensity scores match (1:1) to compare the short-term clinical outcome in 2 groups.No operative deaths occurred in this study. Single-port VATS was associated with shorter operative time, lower postoperation day 1 pain score, and shorter postoperation hospital stay in our cohort study (P = 0.001, <0.001, and 0.039), and propensity scores matched cohort study (P = 0.003, <0.001, and <0.001).Single-port VATS for mediastinum tumor appears to be a safe and promising technique with short-term outcome not inferior to conventional VATS in our cohort study. The long-term oncology outcome may require time and more enrolled patients to be further evaluated.

Tuning the nanotribological behaviors of single silver nanowire through various manipulations

NASA Astrophysics Data System (ADS)

Zeng, Xingzhong; Peng, Yitian; Lang, Haojie; Cao, Xing'an

2018-05-01

Nanotribological characteristics of silver nanowires (Ag NWs) are of great importance for the reliability of their applications where involving mechanical interactions. The frictional behaviors of the Ag NWs with different lengths on SiO2/Si substrate have been investigated directly by atomic force microscopy (AFM) nanomanipulation. The relatively short and long Ag NWs behave like the rigid rods and flexible beams, respectively, and the critical aspect ratio of NWs for the two cases is found to be about 20. The relatively short NWs demonstrates three forms of motion with different frictional behaviors. The friction of the relatively long NWs increases with the bend of the NWs. The long Ag NWs display extraordinary flexibility that can be folded to different shapes, and the folded NWs show a similar frictional behavior with the rigid rods. Different simplified mechanical models are established to match the frictional behaviors of the corresponding Ag NWs. The adhesion between the Ag NWs and substrate is calculated by an indirect method based on the van der Waals force equation to assess their adhesive attraction. These findings may provide insight into the frictional characteristics of Ag NWs and contribute to the quantitative interface design and control for their applications.

Extending the spectrum of DNA sequences retrieved from ancient bones and teeth

PubMed Central

Glocke, Isabelle; Meyer, Matthias

2017-01-01

The number of DNA fragments surviving in ancient bones and teeth is known to decrease with fragment length. Recent genetic analyses of Middle Pleistocene remains have shown that the recovery of extremely short fragments can prove critical for successful retrieval of sequence information from particularly degraded ancient biological material. Current sample preparation techniques, however, are not optimized to recover DNA sequences from fragments shorter than ∼35 base pairs (bp). Here, we show that much shorter DNA fragments are present in ancient skeletal remains but lost during DNA extraction. We present a refined silica-based DNA extraction method that not only enables efficient recovery of molecules as short as 25 bp but also doubles the yield of sequences from longer fragments due to improved recovery of molecules with single-strand breaks. Furthermore, we present strategies for monitoring inefficiencies in library preparation that may result from co-extraction of inhibitory substances during DNA extraction. The combination of DNA extraction and library preparation techniques described here substantially increases the yield of DNA sequences from ancient remains and provides access to a yet unexploited source of highly degraded DNA fragments. Our work may thus open the door for genetic analyses on even older material. PMID:28408382

Design-of-experiments to Reduce Life-cycle Costs in Combat Aircraft Inlets

NASA Technical Reports Server (NTRS)

Anderson, Bernhard H.; Baust, Henry D.; Agrell, Johan

2003-01-01

It is the purpose of this study to demonstrate the viability and economy of Design- of-Experiments (DOE), to arrive at micro-secondary flow control installation designs that achieve optimal inlet performance for different mission strategies. These statistical design concepts were used to investigate the properties of "low unit strength" micro-effector installation. "Low unit strength" micro-effectors are micro-vanes, set a very low angle-of incidence, with very long chord lengths. They are designed to influence the neat wall inlet flow over an extended streamwise distance. In this study, however, the long chord lengths were replicated by a series of short chord length effectors arranged in series over multiple bands of effectors. In order to properly evaluate the performance differences between the single band extended chord length installation designs and the segmented multiband short chord length designs, both sets of installations must be optimal. Critical to achieving optimal micro-secondary flow control installation designs is the understanding of the factor interactions that occur between the multiple bands of micro-scale vane effectors. These factor interactions are best understood and brought together in an optimal manner through a structured DOE process, or more specifically Response Surface Methods (RSM).

Primacy Versus Recency in a Quantitative Model: Activity Is the Critical Distinction

PubMed Central

Greene, Anthony J.; Prepscius, Colin; Levy, William B.

2000-01-01

Behavioral and neurobiological evidence shows that primacy and recency are subserved by memory systems for intermediate- and short-term memory, respectively. A widely accepted explanation of recency is that in short-term memory, new learning overwrites old learning. Primacy is not as well understood, but many hypotheses contend that initial items are better encoded into long-term memory because they have had more opportunity to be rehearsed. A simple, biologically motivated neural network model supports an alternative hypothesis of the distinct processing requirements for primacy and recency given single-trial learning without rehearsal. Simulations of the model exhibit either primacy or recency, but not both simultaneously. The incompatibility of primacy and recency clarifies possible reasons for two neurologically distinct systems. Inhibition, and its control of activity, determines those list items that are acquired and retained. Activity levels that are too low do not provide sufficient connections for learning to occur, while higher activity diminishes capacity. High recurrent inhibition, and progressively diminishing activity, allows acquisition and retention of early items, while later items are never acquired. Conversely, low recurrent inhibition, and the resulting high activity, allows continuous acquisition such that acquisition of later items eventually interferes with the retention of early items. PMID:10706602

Coupling Post-Event and Prospective Analyses for El Niño-related Risk Reduction in Peru

NASA Astrophysics Data System (ADS)

French, Adam; Keating, Adriana; Mechler, Reinhard; Szoenyi, Michael; Cisneros, Abel; Chuquisengo, Orlando; Etienne, Emilie; Ferradas, Pedro

2017-04-01

Analyses in the wake of natural disasters play an important role in identifying how ex ante risk reduction and ex post hazard response activities have both succeeded and fallen short in specific contexts, thereby contributing to recommendations for improving such measures in the future. Event analyses have particular relevance in settings where disasters are likely to reoccur, and especially where recurrence intervals are short. This paper applies the Post Event Review Capability (PERC) methodology to the context of frequently reoccurring El Niño Southern Oscillation (ENSO) events in the country of Peru, where over the last several decades ENSO impacts have generated high levels of damage and economic loss. Rather than analyzing the impacts of a single event, this study builds upon the existing PERC methodology by combining empirical event analysis with a critical examination of risk reduction and adaptation measures implemented both prior to and following several ENSO events in the late 20th and early 21st centuries. Additionally, the paper explores linking the empirical findings regarding the uptake and outcomes of particular risk reduction and adaptation strategies to a prospective, scenario-based approach for projecting risk several decades into the future.

Device for limiting single phase ground fault of mining machines

NASA Astrophysics Data System (ADS)

Fediuk, R. S.; Stoyushko, N. Yu; Yevdokimova, Yu G.; Smoliakov, A. K.; Batarshin, V. O.; Timokhin, R. A.

2017-10-01

The paper shows the reasons and consequences of the single-phase ground fault. With all the variety of devices for limiting the current single-phase ground fault, it was found that the most effective are Peterson coils having different switching circuits. Measuring of the capacity of the network is of great importance in this case, a number of options capacitance measurement are presented. A closer look is taken at the device for limiting the current of single-phase short circuit, developed in the Far Eastern Federal University under the direction of Dr. G.E. Kuvshinov. The calculation of single-phase short-circuit currents in the electrical network, without compensation and with compensation of capacitive current is carried out. Simulation of a single-phase circuit in a network with the proposed device is conducted.

Quiet turbofan STOL aircraft for short haul transportation, volume 1

NASA Technical Reports Server (NTRS)

Renshaw, J. H.

1973-01-01

The characteristics for a quiet turbofan short takeoff aircraft for short haul transportation applications are discussed. The following subjects are examined: (1) representative aircraft configurations, characteristics, and costs associated with the short haul aircraft development and operation, (2) critical technology and technology related problems to be resolved in successful introduction of representative short haul aircraft, (3) relationships between quiet short takeoff aircraft and the economic and social viability of short haul, and (4) identification of high payoff technology areas. In order to properly evaluate the candidate aircraft designs and to determine their economic viability and community acceptance, a real world scenario was developed and projected to 1990.

Thermal algebraic-decay charge liquid driven by competing short-range Coulomb repulsion

NASA Astrophysics Data System (ADS)

Kaneko, Ryui; Nonomura, Yoshihiko; Kohno, Masanori

2018-05-01

We explore the possibility of a Berezinskii-Kosterlitz-Thouless-like critical phase for the charge degrees of freedom in the intermediate-temperature regime between the charge-ordered and disordered phases in two-dimensional systems with competing short-range Coulomb repulsion. As the simplest example, we investigate the extended Hubbard model with on-site and nearest-neighbor Coulomb interactions on a triangular lattice at half filling in the atomic limit by using a classical Monte Carlo method, and find a critical phase, characterized by algebraic decay of the charge correlation function, belonging to the universality class of the two-dimensional XY model with a Z6 anisotropy. Based on the results, we discuss possible conditions for the critical phase in materials.

Effects of space radiation on electronic microcircuits

NASA Technical Reports Server (NTRS)

Kolasinski, W. A.

1989-01-01

The single event effects or phenomena (SEP), which so far have been observed as events falling on one or another of the SE classes: Single Event Upset (SEU), Single Event Latchup (SEL) and Single Event Burnout (SEB), are examined. Single event upset is defined as a lasting, reversible change in the state of a multistable (usually bistable) electronic circuit such as a flip-flop or latch. In a computer memory, SEUs manifest themselves as unexplained bit flips. Since latchup is in general caused by a single event of short duration, the single event part of the SEL term is superfluous. Nevertheless, it is used customarily to differentiate latchup due to a single heavy charged particle striking a sensitive cell from more ordinary kinds of latchup. Single event burnout (SEB) refers usually to total instantaneous failure of a power FET when struck by a single particle, with the device shorting out the power supply. An unforeseen failure of these kinds can be catastrophic to a space mission, and the possibilities are discussed.

Reducing assembly complexity of microbial genomes with single-molecule sequencing.

PubMed

Koren, Sergey; Harhay, Gregory P; Smith, Timothy P L; Bono, James L; Harhay, Dayna M; Mcvey, Scott D; Radune, Diana; Bergman, Nicholas H; Phillippy, Adam M

2013-01-01

The short reads output by first- and second-generation DNA sequencing instruments cannot completely reconstruct microbial chromosomes. Therefore, most genomes have been left unfinished due to the significant resources required to manually close gaps in draft assemblies. Third-generation, single-molecule sequencing addresses this problem by greatly increasing sequencing read length, which simplifies the assembly problem. To measure the benefit of single-molecule sequencing on microbial genome assembly, we sequenced and assembled the genomes of six bacteria and analyzed the repeat complexity of 2,267 complete bacteria and archaea. Our results indicate that the majority of known bacterial and archaeal genomes can be assembled without gaps, at finished-grade quality, using a single PacBio RS sequencing library. These single-library assemblies are also more accurate than typical short-read assemblies and hybrid assemblies of short and long reads. Automated assembly of long, single-molecule sequencing data reduces the cost of microbial finishing to $1,000 for most genomes, and future advances in this technology are expected to drive the cost lower. This is expected to increase the number of completed genomes, improve the quality of microbial genome databases, and enable high-fidelity, population-scale studies of pan-genomes and chromosomal organization.

Critical behaviour and filed dependence of magnetic entropy change in K-doped manganites Pr0.8Na0.2-xKxMnO3 (x = 0.10 and 0.15)

NASA Astrophysics Data System (ADS)

Ben Khlifa, H.; M'nassri, R.; Tarhouni, S.; Regaieg, Y.; Cheikhrouhou-Koubaa, W.; Chniba-Boudjada, N.; Cheikhrouhou, A.

2018-01-01

The orthorhombic Pr0.8Na0.2-xKxMnO3 (x = 0.10 and 0.15) manganites are prepared by using the solid state reaction at high temperatures. The critical exponents (β, γ, δ) are investigated through various techniques such as modified Arrott plot, Kouvel-Fisher method and critical isotherm analysis based on the data of the magnetic measurements recorded around the Curie temperature. The critical exponents are derived from the magnetization data using the Kouvel-Fisher method, are found to be β = 0.32(4) and γ = 1.29(2) at TC 123 K for x = 0.10 and β = 0.31(1) and γ = 1.25(2) at TC 133 K for x = 0.15. The critical exponent values obtained for both samples are comparable to the values predicted by the 3D-Ising model, and have also been verified by the scaling equation of state. Such results demonstrate the existence of ferromagnetic short-range order in our materials. The magnetic entropy changes of polycrystalline samples with a second-order phase transition are investigated. A large magnetic entropy change deduced from isothermal magnetization curves, is observed in our samples with a peak centered on their respective Curie temperatures (TC). The field dependence of the magnetic entropy changes are analyzed, which show power law dependence ΔSmax ≈ a(μ0 H) n at transition temperature. The values of n obey to the Curie Weiss law above the transition temperature. It is shown that for the investigated materials, the magnetic entropy change follow a master curve behaviour. The rescaled magnetic entropy change curves for different applied fields collapse onto a single curve for both samples.

SegAN: Adversarial Network with Multi-scale L1 Loss for Medical Image Segmentation.

PubMed

Xue, Yuan; Xu, Tao; Zhang, Han; Long, L Rodney; Huang, Xiaolei

2018-05-03

Inspired by classic Generative Adversarial Networks (GANs), we propose a novel end-to-end adversarial neural network, called SegAN, for the task of medical image segmentation. Since image segmentation requires dense, pixel-level labeling, the single scalar real/fake output of a classic GAN's discriminator may be ineffective in producing stable and sufficient gradient feedback to the networks. Instead, we use a fully convolutional neural network as the segmentor to generate segmentation label maps, and propose a novel adversarial critic network with a multi-scale L 1 loss function to force the critic and segmentor to learn both global and local features that capture long- and short-range spatial relationships between pixels. In our SegAN framework, the segmentor and critic networks are trained in an alternating fashion in a min-max game: The critic is trained by maximizing a multi-scale loss function, while the segmentor is trained with only gradients passed along by the critic, with the aim to minimize the multi-scale loss function. We show that such a SegAN framework is more effective and stable for the segmentation task, and it leads to better performance than the state-of-the-art U-net segmentation method. We tested our SegAN method using datasets from the MICCAI BRATS brain tumor segmentation challenge. Extensive experimental results demonstrate the effectiveness of the proposed SegAN with multi-scale loss: on BRATS 2013 SegAN gives performance comparable to the state-of-the-art for whole tumor and tumor core segmentation while achieves better precision and sensitivity for Gd-enhance tumor core segmentation; on BRATS 2015 SegAN achieves better performance than the state-of-the-art in both dice score and precision.

Nondestructive Measurement of the Evolution of Layer-Specific Mechanical Properties in Sub-10 nm Bilayer Films.

PubMed

Hoogeboom-Pot, Kathleen M; Turgut, Emrah; Hernandez-Charpak, Jorge N; Shaw, Justin M; Kapteyn, Henry C; Murnane, Margaret M; Nardi, Damiano

2016-08-10

We use short wavelength extreme ultraviolet light to independently measure the mechanical properties of disparate layers within a bilayer film for the first time, with single-monolayer sensitivity. We show that in Ni/Ta nanostructured systems, while their density ratio is not meaningfully changed from that expected in bulk, their elastic properties are significantly modified, where nickel softens while tantalum stiffens, relative to their bulk counterparts. In particular, the presence or absence of the Ta capping layer influences the mechanical properties of the Ni film. This nondestructive nanomechanical measurement technique represents the first approach to date able to distinguish the properties of composite materials well below 100 nm in thickness. This capability is critical for understanding and optimizing the strength, flexibility and reliability of materials in a host of nanostructured electronic, photovoltaic, and thermoelectric devices.

National Facilities Study. Volume 1: Facilities Inventory

NASA Technical Reports Server (NTRS)

1994-01-01

The inventory activity was initiated to solve the critical need for a single source of site specific descriptive and parametric data on major public and privately held aeronautics and aerospace related facilities. This a challenging undertaking due to the scope of the effort and the short lead time in which to assemble the inventory and have it available to support the task group study needs. The inventory remains dynamic as sites are being added and the data is accessed and refined as the study progresses. The inventory activity also included the design and implementation of a computer database and analytical tools to simplify access to the data. This volume describes the steps which were taken to define the data requirements, select sites, and solicit and acquire data from them. A discussion of the inventory structure and analytical tools is also provided.

Multiple DC, single AC converter with a switched DC transformer

DOEpatents

Donnelly, M.K.; Hammerstrom, D.J.

1997-05-20

The invention is an improvement of the PASC inverter, wherein the improvements include the reduction from two shorting gates per transformer to one shorting gate per transformer and replacement of active control of the shorting gate with passive control of the shorting gate. Further advantages are obtained through the use of anti-parallel gate sets. 14 figs.

Multiple DC, single AC converter with a switched DC transformer

DOEpatents

Donnelly, Matthew K.; Hammerstrom, Donald J.

1997-01-01

The invention is an improvement of the PASC inverter, wherein the improvements include the reduction from two shorting gates per transformer to one shorting gate per transformer and replacement of active control of the shorting gate with passive control of the shorting gate. Further advantages are obtained through the use of anti-parallel gate sets.

Dolphins in a Scaled-Down Mediterranean: The Gulf of Corinth's Odontocetes.

PubMed

Bearzi, G; Bonizzoni, S; Santostasi, N L; Furey, N B; Eddy, L; Valavanis, V D; Gimenez, O

The Gulf of Corinth is a 2400-km 2 semi-enclosed inland system (a mediterraneus) in central Greece. Its continental shelf areas, steep bottom relief, and waters up to 500-900m deep offer suitable habitat to neritic and pelagic species. We used photographic capture-recapture, distribution modelling, and direct observations to investigate the abundance, status, habitat preferences, movements, and group size of four odontocete species regularly observed in the Gulf, based on five years (2011-2015) of survey effort from small boats. Striped dolphins (Stenella coeruleoalba) are more abundant (1324 individuals, 95%CI 1158-1515) than was determined from previous estimates. Striped dolphins appear to be confined to the Gulf, where they favour deep and oligotrophic waters, and were encountered in single-species and mixed-species groups. Short-beaked common dolphins (Delphinus delphis) (22 individuals, 95%CI 16-31), individuals with intermediate pigmentation (possibly striped/common dolphin hybrids) (55, 95%CI 36-83), and a single Risso's dolphin (Grampus griseus) were only encountered in mixed-species groups with striped dolphins. Short-beaked common dolphins constitute a discrete conservation unit (subpopulation), and based on the current estimate, would qualify as Critically Endangered according to International Union for the Conservation of Nature (IUCN) Red List criteria. Common bottlenose dolphins (Tursiops truncatus) (39 animals, 95%CI 33-47) occur in single-species groups; they prefer continental shelf waters and areas near fish farms in the northern sector, and several animals appear to move into and out of the Gulf. Additionally, we contribute records of marine fauna and an assessment of the fishing fleet operating in the Gulf. Our study shows that the importance of this vulnerable marine environment has been underestimated, and management action must be taken to mitigate human impact and ensure long-term protection. © 2016 Elsevier Ltd All rights reserved.

Foraminiferal single chamber analyses of heavy metals as a tool for monitoring permanent and short term anthropogenic footprints.

PubMed

Titelboim, Danna; Sadekov, Aleksey; Hyams-Kaphzan, Orit; Almogi-Labin, Ahuva; Herut, Barak; Kucera, Michal; Abramovich, Sigal

2018-03-01

In order to establish environmentally sustainable industries there is a need for high-resolution temporal and spatial monitoring of heavy metal pollutants even at low concentrations before they become hazardous for local ecosystems. Here we present single chamber records of Cu, Zn and Pb in shells of two benthic foraminifera species with different shell types from two shallow coastal stations in Israel: An area adjacent to an electrical power plant and desalination factory (Hadera) and an industrially free nature reserve (Nachsholim). Records of both foraminifera species show elevated metal concentrations in Hadera clearly identifying the footprint of the local industrial facilities. Moreover, short-term events of elevated Cu and Pb concentrations were detected by single chamber analyses. This study demonstrates the potential of using heavy metals anomalies in foraminiferal single chambers as a tool for detecting the industrial footprint of coastal facilities as well as short term events of elevated heavy metals. Copyright © 2018 Elsevier Ltd. All rights reserved.

Pain score of patients undergoing single spot, short pulse laser versus conventional laser for diabetic retinopathy.

PubMed

Mirshahi, Ahmad; Lashay, Alireza; Roozbahani, Mehdi; Fard, Masoud Aghsaei; Molaie, Saber; Mireshghi, Meysam; Zaferani, Mohamad Mehdi

2013-04-01

To compare pain score of single spot short duration time (20 milliseconds) panretinal photocoagulation (PRP) with conventional (100 milliseconds) PRP in diabetic retinopathy. Sixty-six eyes from 33 patients with symmetrical severe non-proliferative diabetic retinopathy (non-PDR) or proliferative diabetic retinopathy (PDR) were enrolled in this prospective randomized controlled trial. One eye of each patient was randomized to undergo conventional and the other eye to undergo short time PRP. Spot size of 200 μm was used in both laser types, and energy was adjusted to achieve moderate burn on the retina. Patients were asked to mark the level of pain felt during the PRP session for each eye on the visual analog scale (VAS) and were examined at 1 week, and at 1, 2, 4 and 6 months. Sixteen women and 17 men with mean age 58.9 ± 7.8 years were evaluated. The conventional method required a mean power of 273 ± 107 mW, whereas the short duration method needed 721 ± 406 mW (P = 0.001). An average of 1,218 ± 441 spots were delivered with the conventional method and an average of 2,125 ± 503 spots were required with the short duration method (P = 0.001). Average pain score was 7.5 ± 1.14 in conventional group and 1.75 ± 0.87 in the short duration group (P = 0.001). At 1 week, 1 month, and 4 months following PRP, the mean changes of central macular thickness (CMT) from baseline in the conventional group remained 29.2 μm (P = 0.008), 40.0 μm (P = 0.001), and 40.2 μm (P = 0.007) greater than the changes in CMT for short time group. Patient acceptance of short time single spot PRP was high, and well-tolerated in a single session by all patients. Moreover, this method is significantly less painful than but just as effective as conventional laser during 6 months of follow-up. The CMT change was more following conventional laser than short time laser.

Sporadic on/off switching of HTLV-1 Tax expression is crucial to maintain the whole population of virus-induced leukemic cells

PubMed Central

Mahgoub, Mohamed; Iwami, Shingo; Nakaoka, Shinji; Koizumi, Yoshiki; Shimura, Kazuya; Matsuoka, Masao

2018-01-01

Viruses causing chronic infection artfully manipulate infected cells to enable viral persistence in vivo under the pressure of immunity. Human T-cell leukemia virus type 1 (HTLV-1) establishes persistent infection mainly in CD4+ T cells in vivo and induces leukemia in this subset. HTLV-1–encoded Tax is a critical transactivator of viral replication and a potent oncoprotein, but its significance in pathogenesis remains obscure due to its very low level of expression in vivo. Here, we show that Tax is expressed in a minor fraction of leukemic cells at any given time, and importantly, its expression spontaneously switches between on and off states. Live cell imaging revealed that the average duration of one episode of Tax expression is ∼19 hours. Knockdown of Tax rapidly induced apoptosis in most cells, indicating that Tax is critical for maintaining the population, even if its short-term expression is limited to a small subpopulation. Single-cell analysis and computational simulation suggest that transient Tax expression triggers antiapoptotic machinery, and this effect continues even after Tax expression is diminished; this activation of the antiapoptotic machinery is the critical event for maintaining the population. In addition, Tax is induced by various cytotoxic stresses and also promotes HTLV-1 replication. Thus, it seems that Tax protects infected cells from apoptosis and increases the chance of viral transmission at a critical moment. Keeping the expression of Tax minimal but inducible on demand is, therefore, a fundamental strategy of HTLV-1 to promote persistent infection and leukemogenesis. PMID:29358408

Working memory for conjunctions relies on the medial temporal lobe.

PubMed

Olson, Ingrid R; Page, Katie; Moore, Katherine Sledge; Chatterjee, Anjan; Verfaellie, Mieke

2006-04-26

A prominent theory of hippocampal function proposes that the hippocampus is importantly involved in relating or binding together separate pieces of information to form an episodic representation. This hypothesis has only been applied to studies of long-term memory because the paradigmatic view of the hippocampus is that it is not critical for short-term forms of memory. However, relational processing is important in many working memory tasks, especially tasks using visual stimuli. Here, we test the hypothesis that the medial temporal lobes are important for relational memory even over short delays. The task required patients with medial temporal lobe amnesia and controls to remember three objects, locations, or object-location conjunctions over 1 or 8 s delays. The results show that working memory for objects and locations was at normal levels, but that memory for conjunctions was severely impaired at 8 s delays. Additional analyses suggest that the hippocampus per se is critical for accurate conjunction working memory. We propose that the hippocampus is critically involved in memory for conjunctions at both short and long delays.

Working Memory for Conjunctions Relies on the Medial Temporal Lobe

PubMed Central

Olson, Ingrid R.; Page, Katie; Moore, Katherine Sledge; Chatterjee, Anjan; Verfaellie, Mieke

2006-01-01

A prominent theory of hippocampal function proposes that the hippocampus is importantly involved in relating or binding together separate pieces of information to form an episodic representation. This hypothesis has only been applied to studies of long-term memory because the paradigmatic view of the hippocampus is that it is not critical for short-term forms of memory. However, relational processing is important in many working memory tasks, especially tasks using visual stimuli. Here, we test the hypothesis that the medial temporal lobes are important for relational memory even over short delays. The task required patients with medial temporal lobe amnesia and controls to remember three objects, locations, or object-location conjunctions over 1 or 8 s delays. The results show that working memory for objects and locations was at normal levels, but that memory for conjunctions was severely impaired at 8 s delays. Additional analyses suggest that the hippocampus per se is critical for accurate conjunction working memory. We propose that the hippocampus is critically involved in memory for conjunctions at both short and long delays. PMID:16641239

Effects of Plyometric Training on Physical Fitness in Team Sport Athletes: A Systematic Review

PubMed Central

Chamari, Karim; Miarka, Bianca; Del Vecchio, Fabricio B.; Chéour, Foued

2016-01-01

Abstract Plyometric training (PT) is a very popular form of physical conditioning of healthy individuals that has been extensively studied over the last decades. In this article, we critically review the available literature related to PT and its effects on physical fitness in team sport athletes. We also considered studies that combined PT with other popular training modalities (e.g. strength/sprint training). Generally, short-term PT (i.e. 2-3 sessions a week for 4-16 weeks) improves jump height, sprint and agility performances in team sport players. Literature shows that short PT (<8 weeks) has the potential to enhance a wide range of athletic performance (i.e. jumping, sprinting and agility) in children and young adult amateur players. Nevertheless, 6 to 7 weeks training appears to be too short to improve physical performance in elite male players. Available evidence suggests that short-term PT on non-rigid surfaces (i.e. aquatic, grass or sand-based PT) could elicit similar increases in jumping, sprinting and agility performances as traditional PT. Furthermore, the combination of various plyometric exercises and the bilateral and unilateral jumps could improve these performances more than the use of single plyometric drills or traditional PT. Thus, the present review shows a greater effect of PT alone on jump and sprint (30 m sprint performance only) performances than the combination of PT with sprint/strength training. Although many issues related to PT remain to be resolved, the results presented in this review allow recommending the use of well-designed and sport-specific PT as a safe and effective training modality for improving jumping and sprint performance as well as agility in team sport athletes. PMID:28149427

Effects of Plyometric Training on Physical Fitness in Team Sport Athletes: A Systematic Review.

PubMed

Slimani, Maamer; Chamari, Karim; Miarka, Bianca; Del Vecchio, Fabricio B; Chéour, Foued

2016-12-01

Plyometric training (PT) is a very popular form of physical conditioning of healthy individuals that has been extensively studied over the last decades. In this article, we critically review the available literature related to PT and its effects on physical fitness in team sport athletes. We also considered studies that combined PT with other popular training modalities (e.g. strength/sprint training). Generally, short-term PT (i.e. 2-3 sessions a week for 4-16 weeks) improves jump height, sprint and agility performances in team sport players. Literature shows that short PT (<8 weeks) has the potential to enhance a wide range of athletic performance (i.e. jumping, sprinting and agility) in children and young adult amateur players. Nevertheless, 6 to 7 weeks training appears to be too short to improve physical performance in elite male players. Available evidence suggests that short-term PT on non-rigid surfaces (i.e. aquatic, grass or sand-based PT) could elicit similar increases in jumping, sprinting and agility performances as traditional PT. Furthermore, the combination of various plyometric exercises and the bilateral and unilateral jumps could improve these performances more than the use of single plyometric drills or traditional PT. Thus, the present review shows a greater effect of PT alone on jump and sprint (30 m sprint performance only) performances than the combination of PT with sprint/strength training. Although many issues related to PT remain to be resolved, the results presented in this review allow recommending the use of well-designed and sport-specific PT as a safe and effective training modality for improving jumping and sprint performance as well as agility in team sport athletes.

An XRCC4 Splice Mutation Associated With Severe Short Stature, Gonadal Failure, and Early-Onset Metabolic Syndrome

PubMed Central

de Bruin, Christiaan; Mericq, Verónica; Andrew, Shayne F.; van Duyvenvoorde, Hermine A.; Verkaik, Nicole S.; Losekoot, Monique; Porollo, Aleksey; Garcia, Hernán; Kuang, Yi; Hanson, Dan; Clayton, Peter; van Gent, Dik C.; Wit, Jan M.; Hwa, Vivian

2015-01-01

Context: Severe short stature can be caused by defects in numerous biological processes including defects in IGF-1 signaling, centromere function, cell cycle control, and DNA damage repair. Many syndromic causes of short stature are associated with medical comorbidities including hypogonadism and microcephaly. Objective: To identify an underlying genetic etiology in two siblings with severe short stature and gonadal failure. Design: Clinical phenotyping, genetic analysis, complemented by in vitro functional studies of the candidate gene. Setting: An academic pediatric endocrinology clinic. Patients or Other Participants: Two adult siblings (male patient [P1] and female patient 2 [P2]) presented with a history of severe postnatal growth failure (adult heights: P1, −6.8 SD score; P2, −4 SD score), microcephaly, primary gonadal failure, and early-onset metabolic syndrome in late adolescence. In addition, P2 developed a malignant gastrointestinal stromal tumor at age 28. Intervention(s): Single nucleotide polymorphism microarray and exome sequencing. Results: Combined microarray analysis and whole exome sequencing of the two affected siblings and one unaffected sister identified a homozygous variant in XRCC4 as the probable candidate variant. Sanger sequencing and mRNA studies revealed a splice variant resulting in an in-frame deletion of 23 amino acids. Primary fibroblasts (P1) showed a DNA damage repair defect. Conclusions: In this study we have identified a novel pathogenic variant in XRCC4, a gene that plays a critical role in non-homologous end-joining DNA repair. This finding expands the spectrum of DNA damage repair syndromes to include XRCC4 deficiency causing severe postnatal growth failure, microcephaly, gonadal failure, metabolic syndrome, and possibly tumor predisposition. PMID:25742519

Telomere Length Determines TERRA and R-Loop Regulation through the Cell Cycle.

PubMed

Graf, Marco; Bonetti, Diego; Lockhart, Arianna; Serhal, Kamar; Kellner, Vanessa; Maicher, André; Jolivet, Pascale; Teixeira, Maria Teresa; Luke, Brian

2017-06-29

Maintenance of a minimal telomere length is essential to prevent cellular senescence. When critically short telomeres arise in the absence of telomerase, they can be repaired by homology-directed repair (HDR) to prevent premature senescence onset. It is unclear why specifically the shortest telomeres are targeted for HDR. We demonstrate that the non-coding RNA TERRA accumulates as HDR-promoting RNA-DNA hybrids (R-loops) preferentially at very short telomeres. The increased level of TERRA and R-loops, exclusively at short telomeres, is due to a local defect in RNA degradation by the Rat1 and RNase H2 nucleases, respectively. Consequently, the coordination of TERRA degradation with telomere replication is altered at shortened telomeres. R-loop persistence at short telomeres contributes to activation of the DNA damage response (DDR) and promotes recruitment of the Rad51 recombinase. Thus, the telomere length-dependent regulation of TERRA and TERRA R-loops is a critical determinant of the rate of replicative senescence. Copyright © 2017 Elsevier Inc. All rights reserved.

Environmental stress cracking of polymers

NASA Technical Reports Server (NTRS)

Mahan, K. I.

1980-01-01

A two point bending method for use in studying the environmental stress cracking and crazing phenomena is described and demonstrated for a variety of polymer/solvent systems. Critical strain values obtained from these curves are reported for various polymer/solvent systems including a considerable number of systems for which critical strain values have not been previously reported. Polymers studied using this technique include polycarbonate (PC), ABS, high impact styrene (HIS), polyphenylene oxide (PPO), and polymethyl methacrylate (PMMA). Critical strain values obtained using this method compared favorably with available existing data. The major advantage of the technique is the ability to obtain time vs. strain curves over a short period of time. The data obtained suggests that over a short period of time the transition in most of the polymer solvent systems is more gradual than previously believed.

Three Transits for the Price of One: Super-Earth Transits of the Nearest Planetary System Discovered By Kepler/K2

NASA Astrophysics Data System (ADS)

Redfield, Seth; Niraula, Prajwal; Hedges, Christina; Crossfield, Ian; Kreidberg, Laura; Greene, Tom; Rodriguez, Joey; Vanderburg, Andrew; Laughlin, Gregory; Millholland, Sarah; Wang, Songhu; Cochran, William; Livingston, John; Gandolfi, Davide; Guenther, Eike; Fridlund, Malcolm; Korth, Judith

2018-05-01

We propose primary transit observations of three Super-Earth planets in the newly discovered planetary system around a bright, nearby star, GJ 9827. We recently announced the detection of three super-Earth planets in 1:3:5 commensurability, the inner planet, GJ 9827 b having a period of 1.2 days. This is the nearest planetary system that Kepler or K2 has found, at 30 pc, and given its brightness is one of the top systems for follow-up characterization. This system presents a unique opportunity to acquire three planetary transits for the price of one. There are several opportunities in the Spitzer visibility windows to obtain all three transits in a short period of time. We propose 3.6 micron observations of all three Super-Earth transits in a single 18-hour observation window. The proximity to a 1:3:5 resonance is intriguing from a dynamical standpoint as well. Indeed, anomalous transit timing offsets have been measured for planet d in Hubble observations that suffer from partial phase coverage. The short cadence and extended coverage of Spitzer is essential to provide a firm determination of the ephemerides and characterize any transit timing variations. Constraining these orbital parameters is critical for follow-up observations from space and ground-based telescopes. Due to the brightness of the host star, this planetary system is likely to be extensively observed in the years to come. Indeed, our team has acquired observations of the planets orbiting GJ9827 with Hubble in the ultraviolet and infrared. The proposed observations will provide infrared atmospheric measurements and firm orbital characterization which is critical for planning and designing future observations, in particular atmospheric characterization with JWST.

Short-term versus long-term administration of single prophylactic antibiotic in elective gastric tumor surgery.

PubMed

Wang, Fang; Chen, Xin-Zu; Liu, Jie; Yang, Kun; Zhang, Bo; Chen, Zhi-Xin; Chen, Jia-Ping; Hu, Jian-Kun; Zhou, Zong-Guang; Mo, Xian-Min; Mo, Xian-Min

2012-09-01

To evaluate short-term versus long-term single prophylactic antibiotic for elective gastric tumor surgery. Patients in a single surgical team undergoing elective gastric tumor surgery were enrolled from November 2009 to December 2010. The included patients were aged from 18 to 70 years without conditions as severe comorbidity, preoperative infectious diseases, antibiotic administration 48 h before surgery, exploratory laparotomy only or combined colorectal resection, neoadjuvant chemotherapy, or steroid administration before surgery. The overall and infection-related postoperative complications and also economic outcomes were analyzed. The software SPSS 17.0 and TreeAge Pro 2007 were used for statistics. Patients (n=158 (45 vs. 113)) were enrolled in short-term and long-term groups. No death cases occurred. Overall postoperative complication rates were 8.9% and 8.0%, respectively (p=1.000). The rates of infection related complications were 8.9% and 4.4%, respectively (p=0.231). No surgical site infection (SSI) occurred in the short-term group, whereas SSI was 1.8% in the long-term group. Total hospitalization cost (THC) of short-term branch was 36,557RMB per patients and preferable against 39,523RMB of long-term branch. Incremental cost-effectiveness analysis showed there was a 10 times interval between the extra healthcare expenditure of benefit and harm. Short-term administration did not increase the risk of postoperative complications and was more cost-effective.

Encapsulating Moral Dilemma through Short Story: Challenging Pre-Service Teachers to Critically Think about the Student/Teacher Personality and Leadership Dynamic

ERIC Educational Resources Information Center

Lennon, Sean M.

2007-01-01

Pre-service teachers and education students in three different classes (N = 53) were directed to read a short story by Mark Twain titled "Heaven or Hell?" written within a compilation of short stories late in his career. The story, "Heaven or Hell?" illustrates a koan, or an unanswerable moral or ethical dilemma. The students,…

Solving the Mystery of the Short-Hard Gamma-Ray Bursts

NASA Astrophysics Data System (ADS)

Fox, Derek

2005-07-01

Eight years after the afterglow detections that revolutionized studies of the long-soft gamma-ray bursts, not even one afterglow of a short-hard GRB has been seen, and the nature of these events has become one of the most important problems in GRB research. The Swift satellite, expected to be in full operation throughout Cycle 14, will report few-arcsecond localizations for short-hard bursts in minutes, enabling prompt, deep optical afterglow searches for the first time. Discovery and observation of the first short-hard optical afterglows will answer most of the critical questions about these events: What are their distances and energies? Do they occur in distant galaxies, and if so, in which regions of those galaxies? Are they the result of collimated or quasi-spherical explosions? In combination with an extensive rapid-response ground-based campaign, we propose to make the critical high-sensitivity HST TOO observations that will allow us to answer these questions. If theorists are correct in attributing the short-hard bursts to binary neutron star coalescence events, then they will serve as signposts to the primary targeted source population for ground-based gravitational-wave detectors, and short-hard burst studies will have a vital role to play in guiding those observations.

Nurses' Perceptions of Pediatric Intensive Care Unit Environment and Work Experience After Transition to Single-Patient Rooms.

PubMed

Kudchadkar, Sapna R; Beers, M Claire; Ascenzi, Judith A; Jastaniah, Ebaa; Punjabi, Naresh M

2016-09-01

The architectural design of the pediatric intensive care unit may play a major role in optimizing the environment to promote patients' sleep while improving stress levels and the work experience of critical care nurses. To examine changes in nurses' perceptions of the environment of a pediatric critical care unit for promotion of patients' sleep and the nurses' work experience after a transition from multipatient rooms to single-patient rooms. A cross-sectional survey of nurses was conducted before and after the move to a new hospital building in which all rooms in the pediatric critical care unit were single-patient rooms. Nurses reported that compared with multipatient rooms, single-patient private rooms were more conducive to patients sleeping well at night and promoted a more normal sleep-wake cycle (P < .001). Monitors/alarms and staff conversations were the biggest factors that adversely influenced the environment for sleep promotion in both settings. Nurses were less annoyed by noise in single-patient rooms (33%) than in multipatient rooms (79%; P < .001) and reported improved exposure to sunlight. Use of single-patient rooms rather than multipatient rooms improved nurses' perceptions of the pediatric intensive care unit environment for promoting patients' sleep and the nurses' own work experience. ©2016 American Association of Critical-Care Nurses.

Short-Term Temporal Stability in Observed Retail Food Characteristics

ERIC Educational Resources Information Center

Zenk, Shannon N.; Grigsby-Toussaint, Diana S.; Curry, Susan J.; Berbaum, Michael; Schneider, Linda

2010-01-01

Objective: Use of direct observation to characterize neighborhood retail food environments is increasing, but to date most studies have relied on a single observation. If food availability, prices, and quality vary over short time periods, repeated measures may be needed to portray these food characteristics. This study evaluated short-term…

Anisotropic thermodynamic and transport properties of single-crystalline CaKFe 4 As 4

DOE PAGES

Meier, W. R.; Kong, T.; Kaluarachchi, U. S.; ...

2016-08-01

We grew single-crystalline, single-phase CaKFe 4As 4 out of a high-temperature, quaternary melt. Temperature-dependent measurements of x-ray diffraction, anisotropic electrical resistivity, elastoresistivity, thermoelectric power, Hall effect, magnetization, and specific heat, combined with field-dependent measurements of electrical resistivity and field and pressure-dependent measurements of magnetization indicate that CaKFe 4As 4 is an ordered, stoichiometric, Fe-based superconductor with a superconducting critical temperature, T c=35.0±0.2 K. Other than superconductivity, there is no indication of any other phase transition for 1.8K≤T≤300 K. All of these thermodynamic and transport data reveal striking similarities to those found for optimally or slightly overdoped (Ba 1-xKx)Fe 2As 2, suggesting that stoichiometric CaKFe 4As 4 is intrinsically close to what is referred to as “optimal-doped” on a generalized, Fe-based superconductor, phase diagram. Furthermore, the anisotropic superconducting upper critical field, H c2(T), of CaKFe 4As 4 was determined up to 630 kOe. The anisotropy parameter γ(T)=Hmore » $$⊥\\atop{c2}$$/H$$∥\\atop{c2}$$, for H applied perpendicular and parallel to the c axis, decreases from ≃2.5 at T c to ≃1.5 at 25 K, which can be explained by interplay of paramagnetic pair breaking and orbital effects. The slopes of dH$$∥\\atop{c2}$$/dT≃-44 kOe/K and dH$$⊥\\atop{c2}$$/dT≃-109 kOe/K at T c yield an electron mass anisotropy of m ⊥/m ∥≃1/6 and short Ginzburg-Landau coherence lengths ξ ∥(0)≃5.8Å and ξ ⊥(0)≃14.3Å. Finally, the value of H$$⊥\\atop{c2}$$(0) can be extrapolated to ≃920 kOe, well above the BCS paramagnetic limit.« less

Short-Range Correlated Magnetic Core-Shell CrO₂/Cr₂O₃ Nanorods: Experimental Observations and Theoretical Considerations.

PubMed

Gandhi, Ashish C; Li, Tai-Yue; Chan, Ting Shan; Wu, Sheng Yun

2018-05-09

With the evolution of synthesis and the critical characterization of core-shell nanostructures, short-range magnetic correlation is of prime interest in employing their properties to develop novel devices and widespread applications. In this regard, a novel approach of the magnetic core-shell saturated magnetization (CSSM) cylinder model solely based on the contribution of saturated magnetization in one-dimensional CrO₂/Cr₂O₃ core-shell nanorods (NRs) has been developed and applied for the determination of core-diameter and shell-thickness. The nanosized effect leads to a short-range magnetic correlation of ferromagnetic core-CrO₂ extracted from CSSM, which can be explained using finite size scaling method. The outcome of this study is important in terms of utilizing magnetic properties for the critical characterization of core-shell nanomagnetic materials.

Quantum criticality of a spin-1 XY model with easy-plane single-ion anisotropy via a two-time Green function approach avoiding the Anderson-Callen decoupling

NASA Astrophysics Data System (ADS)

Mercaldo, M. T.; Rabuffo, I.; De Cesare, L.; Caramico D'Auria, A.

2016-04-01

In this work we study the quantum phase transition, the phase diagram and the quantum criticality induced by the easy-plane single-ion anisotropy in a d-dimensional quantum spin-1 XY model in absence of an external longitudinal magnetic field. We employ the two-time Green function method by avoiding the Anderson-Callen decoupling of spin operators at the same sites which is of doubtful accuracy. Following the original Devlin procedure we treat exactly the higher order single-site anisotropy Green functions and use Tyablikov-like decouplings for the exchange higher order ones. The related self-consistent equations appear suitable for an analysis of the thermodynamic properties at and around second order phase transition points. Remarkably, the equivalence between the microscopic spin model and the continuous O(2) -vector model with transverse-Ising model (TIM)-like dynamics, characterized by a dynamic critical exponent z=1, emerges at low temperatures close to the quantum critical point with the single-ion anisotropy parameter D as the non-thermal control parameter. The zero-temperature critic anisotropy parameter Dc is obtained for dimensionalities d > 1 as a function of the microscopic exchange coupling parameter and the related numerical data for different lattices are found to be in reasonable agreement with those obtained by means of alternative analytical and numerical methods. For d > 2, and in particular for d=3, we determine the finite-temperature critical line ending in the quantum critical point and the related TIM-like shift exponent, consistently with recent renormalization group predictions. The main crossover lines between different asymptotic regimes around the quantum critical point are also estimated providing a global phase diagram and a quantum criticality very similar to the conventional ones.

Homogenized modeling methodology for 18650 lithium-ion battery module under large deformation

PubMed Central

Tang, Liang; Cheng, Pengle

2017-01-01

Effective lithium-ion battery module modeling has become a bottleneck for full-size electric vehicle crash safety numerical simulation. Modeling every single cell in detail would be costly. However, computational accuracy could be lost if the module is modeled by using a simple bulk material or rigid body. To solve this critical engineering problem, a general method to establish a computational homogenized model for the cylindrical battery module is proposed. A single battery cell model is developed and validated through radial compression and bending experiments. To analyze the homogenized mechanical properties of the module, a representative unit cell (RUC) is extracted with the periodic boundary condition applied on it. An elastic–plastic constitutive model is established to describe the computational homogenized model for the module. Two typical packing modes, i.e., cubic dense packing and hexagonal packing for the homogenized equivalent battery module (EBM) model, are targeted for validation compression tests, as well as the models with detailed single cell description. Further, the homogenized EBM model is confirmed to agree reasonably well with the detailed battery module (DBM) model for different packing modes with a length scale of up to 15 × 15 cells and 12% deformation where the short circuit takes place. The suggested homogenized model for battery module makes way for battery module and pack safety evaluation for full-size electric vehicle crashworthiness analysis. PMID:28746390

Homogenized modeling methodology for 18650 lithium-ion battery module under large deformation.

PubMed

Tang, Liang; Zhang, Jinjie; Cheng, Pengle

2017-01-01

Effective lithium-ion battery module modeling has become a bottleneck for full-size electric vehicle crash safety numerical simulation. Modeling every single cell in detail would be costly. However, computational accuracy could be lost if the module is modeled by using a simple bulk material or rigid body. To solve this critical engineering problem, a general method to establish a computational homogenized model for the cylindrical battery module is proposed. A single battery cell model is developed and validated through radial compression and bending experiments. To analyze the homogenized mechanical properties of the module, a representative unit cell (RUC) is extracted with the periodic boundary condition applied on it. An elastic-plastic constitutive model is established to describe the computational homogenized model for the module. Two typical packing modes, i.e., cubic dense packing and hexagonal packing for the homogenized equivalent battery module (EBM) model, are targeted for validation compression tests, as well as the models with detailed single cell description. Further, the homogenized EBM model is confirmed to agree reasonably well with the detailed battery module (DBM) model for different packing modes with a length scale of up to 15 × 15 cells and 12% deformation where the short circuit takes place. The suggested homogenized model for battery module makes way for battery module and pack safety evaluation for full-size electric vehicle crashworthiness analysis.

Neutron and x-ray scattering study of phonon dispersion and diffuse scattering in (Na ,Bi ) Ti O3-x BaTi O3 single crystals near the morphotropic phase boundary

NASA Astrophysics Data System (ADS)

Luo, Chengtao; Bansal, Dipanshu; Li, Jiefang; Viehland, Dwight; Winn, Barry; Ren, Yang; Li, Xiaobing; Luo, Haosu; Delaire, Olivier

2017-11-01

Neutron and x-ray scattering measurements were performed on (N a1 /2B i1 /2 ) Ti O3-x at %BaTi O3 (NBT-x BT ) single crystals (x =4 , 5, 6.5, and 7.5) across the morphotropic phase boundary (MPB), as a function of both composition and temperature, and probing both structural and dynamical aspects. In addition to the known diffuse scattering pattern near the Γ points, our measurements revealed new, faint superlattice peaks, as well as an extensive diffuse scattering network, revealing a short-range ordering of polar nanoregions (PNR) with a static stacking morphology. In samples with compositions closest to the MPB, our inelastic neutron scattering investigations of the phonon dynamics showed two unusual features in the acoustic phonon branches, between the superlattice points, and between the superlattice points and Γ points, respectively. These critical elements are not present in the other compositions away from the MPB, which suggests that these features may be related to the tilt modes coupling behavior near the MPB.

Multi-hazard risk analysis using the FP7 RASOR Platform

NASA Astrophysics Data System (ADS)

Koudogbo, Fifamè N.; Duro, Javier; Rossi, Lauro; Rudari, Roberto; Eddy, Andrew

2014-10-01

Climate change challenges our understanding of risk by modifying hazards and their interactions. Sudden increases in population and rapid urbanization are changing exposure to risk around the globe, making impacts harder to predict. Despite the availability of operational mapping products, there is no single tool to integrate diverse data and products across hazards, update exposure data quickly and make scenario-based predictions to support both short and long-term risk-related decisions. RASOR (Rapid Analysis and Spatialization Of Risk) will develop a platform to perform multi-hazard risk analysis for the full cycle of disaster management, including targeted support to critical infrastructure monitoring and climate change impact assessment. A scenario-driven query system simulates future scenarios based on existing or assumed conditions and compares them with historical scenarios. RASOR will thus offer a single work environment that generates new risk information across hazards, across data types (satellite EO, in-situ), across user communities (global, local, climate, civil protection, insurance, etc.) and across the world. Five case study areas are considered within the project, located in Haiti, Indonesia, Netherlands, Italy and Greece. Initially available over those demonstration areas, RASOR will ultimately offer global services to support in-depth risk assessment and full-cycle risk management.

Neutron and x-ray scattering study of phonon dispersion and diffuse scattering in ( Na , Bi ) Ti O 3 - x BaTi O 3 single crystals near the morphotropic phase boundary

DOE PAGES

Luo, Chengtao; Bansal, Dipanshu; Li, Jiefang; ...

2017-11-10

Neutron and x-ray scattering measurements were performed on (Na 1/2Bi 1/2)TiO 3-x at % BaTiO 3 (NBT-xBT) single crystals (x = 4, 5, 6.5, and 7.5) across the morphotropic phase boundary (MPB), as a function of both composition and temperature, and probing both structural and dynamical aspects. In addition to the known diffuse scattering pattern near the gamma points, our measurements revealed new, faint superlattice peaks, as well as an extensive diffuse scattering network, revealing a short-range ordering of polar nanoregions (PNR) with a static stacking morphology. Furthermore, in samples with compositions closest to the MPB, our inelastic neutron scatteringmore » investigations of the phonon dynamics showed two unusual features in the acoustic phonon branches, between the superlattice points, and between the superlattice points and gamma points, respectively. Finally, these critical elements are not present in the other compositions away from the MPB, which suggests that these features may be related to the tilt modes coupling behavior near the MPB.« less

Neutron and x-ray scattering study of phonon dispersion and diffuse scattering in ( Na , Bi ) Ti O 3 - x BaTi O 3 single crystals near the morphotropic phase boundary

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

Luo, Chengtao; Bansal, Dipanshu; Li, Jiefang

Neutron and x-ray scattering measurements were performed on (Na 1/2Bi 1/2)TiO 3-x at % BaTiO 3 (NBT-xBT) single crystals (x = 4, 5, 6.5, and 7.5) across the morphotropic phase boundary (MPB), as a function of both composition and temperature, and probing both structural and dynamical aspects. In addition to the known diffuse scattering pattern near the gamma points, our measurements revealed new, faint superlattice peaks, as well as an extensive diffuse scattering network, revealing a short-range ordering of polar nanoregions (PNR) with a static stacking morphology. Furthermore, in samples with compositions closest to the MPB, our inelastic neutron scatteringmore » investigations of the phonon dynamics showed two unusual features in the acoustic phonon branches, between the superlattice points, and between the superlattice points and gamma points, respectively. Finally, these critical elements are not present in the other compositions away from the MPB, which suggests that these features may be related to the tilt modes coupling behavior near the MPB.« less

One-step direct-laser metal writing of sub-100 nm 3D silver nanostructures in a gelatin matrix

NASA Astrophysics Data System (ADS)

Kang, SeungYeon; Vora, Kevin; Mazur, Eric

2015-03-01

Developing an ability to fabricate high-resolution, 3D metal nanostructures in a stretchable 3D matrix is a critical step to realizing novel optoelectronic devices such as tunable bulk metal-dielectric optical devices and THz metamaterial devices that are not feasible with alternative techniques. We report a new chemistry method to fabricate high-resolution, 3D silver nanostructures using a femtosecond-laser direct metal writing technique. Previously, only fabrication of 3D polymeric structures or single-/few-layer metal structures was possible. Our method takes advantage of unique gelatin properties to overcome such previous limitations as limited freedom in 3D material design and short sample lifetime. We fabricate more than 15 layers of 3D silver nanostructures with a resolution of less than 100 nm in a stable dielectric matrix that is flexible and has high large transparency that is well-matched for potential applications in the optical and THz metamaterial regimes. This is a single-step process that does not require any further processing. This work will be of interest to those interested in fabrication methods that utilize nonlinear light-matter interactions and the realization of future metamaterials.

An IUE survey of activity in red giants and supergiants

NASA Technical Reports Server (NTRS)

Oznovich, I.; Gibson, D. M.

1987-01-01

Chromospheric and transition region line activity is examined in apparently single red giants and supergiants using the IUE archives. Low-resolution, large-aperture spectra (mostly short-wavelength) were used to search for variations of emission-line fluxes in time. A series of automatic processing procedures were implemented in order to uniformly calibrate a large number of spectra, fit continua to each of them, determine the fluxes of as many as 18 emission lines, and compare them at different epochs. A method is offered to compute the overall error in the integrated flux, a critical measure of activity, independent of the observing and processing details. This processing was applied to above 120 images of 26 stars taken over a period of 7 yr (1978-1984). Four stars showed UV emission-line flux variations. Alpha Aqr, Beta Peg, and Sigma Oph showed a single enhanced-emission event in all detectable emission lines. Gamma Aql exhibited an increase in the flux level of the O I (1641 A) line in mid-1981 with no comparable change in any other lines. These four stars lie in a region of the H-R diagram in which time-dependent circumstellar absorption lines appear.

A Probabilistic Palimpsest Model of Visual Short-term Memory

PubMed Central

Matthey, Loic; Bays, Paul M.; Dayan, Peter

2015-01-01

Working memory plays a key role in cognition, and yet its mechanisms remain much debated. Human performance on memory tasks is severely limited; however, the two major classes of theory explaining the limits leave open questions about key issues such as how multiple simultaneously-represented items can be distinguished. We propose a palimpsest model, with the occurrent activity of a single population of neurons coding for several multi-featured items. Using a probabilistic approach to storage and recall, we show how this model can account for many qualitative aspects of existing experimental data. In our account, the underlying nature of a memory item depends entirely on the characteristics of the population representation, and we provide analytical and numerical insights into critical issues such as multiplicity and binding. We consider representations in which information about individual feature values is partially separate from the information about binding that creates single items out of multiple features. An appropriate balance between these two types of information is required to capture fully the different types of error seen in human experimental data. Our model provides the first principled account of misbinding errors. We also suggest a specific set of stimuli designed to elucidate the representations that subjects actually employ. PMID:25611204

A probabilistic palimpsest model of visual short-term memory.

PubMed

Matthey, Loic; Bays, Paul M; Dayan, Peter

2015-01-01

Working memory plays a key role in cognition, and yet its mechanisms remain much debated. Human performance on memory tasks is severely limited; however, the two major classes of theory explaining the limits leave open questions about key issues such as how multiple simultaneously-represented items can be distinguished. We propose a palimpsest model, with the occurrent activity of a single population of neurons coding for several multi-featured items. Using a probabilistic approach to storage and recall, we show how this model can account for many qualitative aspects of existing experimental data. In our account, the underlying nature of a memory item depends entirely on the characteristics of the population representation, and we provide analytical and numerical insights into critical issues such as multiplicity and binding. We consider representations in which information about individual feature values is partially separate from the information about binding that creates single items out of multiple features. An appropriate balance between these two types of information is required to capture fully the different types of error seen in human experimental data. Our model provides the first principled account of misbinding errors. We also suggest a specific set of stimuli designed to elucidate the representations that subjects actually employ.

The Relevant Role of Dislocations in the Martensitic Transformations in Cu-Al-Ni Single Crystals

NASA Astrophysics Data System (ADS)

Gastien, R.; Sade, M.; Lovey, F. C.

2018-03-01

The interaction between dislocations and martensitic transformations in Cu-Al-Ni alloys is shortly reviewed. Results from many researchers are critically analyzed towards a clear interpretation of the relevant role played by dislocations on the properties of shape memory alloys in Cu-based alloys. Both thermally and stress-induced transformations are considered and focus is paid on two types of transitions, the β→β' and the formation of a mixture of martensites: β→β' + γ'. After cycling in the range where both martensites are formed, the twinned γ' phase is inhibited and cycling evolves into the formation of only β'. A model which considers the difference in energy of each γ' twin variant due to the introduced dislocations quantitatively explains the inhibition of γ' in both thermally and stress-induced cycling. The type of dislocations which are mainly introduced, mixed with Burgers vector belonging to the basal plane of the β' martensite, enables also to explain the unmodified mechanical behavior during β→β' cycling. The reported behavior shows interesting advantages of Cu-Al-Ni single crystals if mechanical properties are comparatively considered with those in other Cu-based alloys.

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

Fahrenkrog, Annette M.; Neves, Leandro G.; Resende, Jr., Marcio F. R.

Genome-wide association studies (GWAS) have been used extensively to dissect the genetic regulation of complex traits in plants. These studies have focused largely on the analysis of common genetic variants despite the abundance of rare polymorphisms in several species, and their potential role in trait variation. Here, we conducted the first GWAS in Populus deltoides, a genetically diverse keystone forest species in North America and an important short rotation woody crop for the bioenergy industry. We searched for associations between eight growth and wood composition traits, and common and low-frequency single-nucleotide polymorphisms detected by targeted resequencing of 18 153 genesmore » in a population of 391 unrelated individuals. To increase power to detect associations with low-frequency variants, multiple-marker association tests were used in combination with single-marker association tests. Significant associations were discovered for all phenotypes and are indicative that low-frequency polymorphisms contribute to phenotypic variance of several bioenergy traits. Our results suggest that both common and low-frequency variants need to be considered for a comprehensive understanding of the genetic regulation of complex traits, particularly in species that carry large numbers of rare polymorphisms. Lastly, these polymorphisms may be critical for the development of specialized plant feedstocks for bioenergy.« less

Short normal stature and psychosocial disadvantage: a critical review of the evidence.

PubMed

Voss, L D

2001-06-01

Physicians and parents alike are under increasing pressure to identify and to treat short stature, but intervention implies the presence of some pathology, physical or psychological, that can be corrected. Where there is true GH deficiency, the argument for replacement is uncontroversial. It is less compelling where GH 'insufficiency' is diagnosed. In the case of the short, but otherwise normal, child the indications for therapy are even less clear. Short stature, per se, is clearly not a disease, in spite of the perception by some practitioners that the rate of growth of such children is abnormal. Short stature is, however, commonly perceived to be associated with social and psychological disadvantage, yet many of these misperceptions about short stature can be challenged. A critical review of the literature pertaining to the psychosocial correlates of short stature uncovers much flawed evidence. Most importantly, the belief, widely held by paediatricians, that short children are likely to be significantly disadvantaged, has been founded largely on data from clinic-referred samples. In such studies, children with real (or perceived) behavioural or academic problems are likely to be overly represented. Publications arising from such studies, however, inevitably lead to an increase in the demand for treatment both from and for those who previously had no such concern. In contrast, data from a well controlled, prospective population-based study suggest the essential normality of the short normal child. Parents and children alike should be reassured by these findings. In the absence of clear pathology, physical or psychological, GH therapy for short but otherwise normal children must therefore, in most cases, be deemed cosmetic, raising issues as to the ethics of so-called "plastic endocrinology".

Critical behavior of the order-disorder phase transition in β -brass investigated by x-ray scattering

NASA Astrophysics Data System (ADS)

Madsen, A.; Als-Nielsen, J.; Hallmann, J.; Roth, T.; Lu, W.

2016-07-01

β -brass exhibits an archetypical example of an order-disorder transition with a critical behavior that was previously investigated by neutron scattering. The data were well described by the three-dimensional (3d) Ising model but the relatively crude experimental resolution prevented an in-depth examination of the single-length scaling hypothesis, a cornerstone in the theory of critical phenomena. With the development of synchrotron x-ray experiments, high-resolution data could be recorded and surprisingly it was found that the single-length scaling did not hold in most critical systems, possibly due to strain originating from surface defects and/or impurities. In this paper we demonstrate single-length critical behavior using high-resolution x-ray scattering in β -brass. The investigations confirm that β -brass behaves like a 3d Ising system over a wide range of length scales comprising correlated clusters of millions of atoms. To vary the surface sensitivity, experiments have been performed both in Bragg reflection and Laue transmission geometries but without any substantial differences observed in the scaling and critical behavior.

Designing Writing Programs in Business and Industry.

ERIC Educational Resources Information Center

Freed, Richard C.

Current training in writing for business and industry usually takes the form of short courses. However, the short course is an inappropriate way to teach writing because it is inefficient, represents writing behaviors or strategies inappropriate for some writers, rarely allows time for adequate criticism and revision, presents too much material in…

Relationships among nocturnal jaw muscle activities, decreased esophageal pH, and sleep positions.

PubMed

Miyawaki, Shouichi; Tanimoto, Yuko; Araki, Yoshiko; Katayama, Akira; Imai, Mikako; Takano-Yamamoto, Teruko

2004-11-01

The purpose of this study was to examine the relationships among nocturnal jaw muscle activities, decreased esophageal pH, and sleep positions. Twelve adult volunteers, including 4 bruxism patients, participated in this study. Portable pH monitoring, electromyography of the temporal muscle, and audio-video recordings were conducted during the night in the subjects' homes. Rhythmic masticatory muscle activity (RMMA) episodes were observed most frequently, with single short-burst episodes the second most frequent. The frequencies of RMMA, single short-burst, and clenching episodes were significantly higher during decreased esophageal pH episodes than those during other times. Both the electromyography and the decreased esophageal pH episodes were most frequently observed in the supine position. These results suggest that most jaw muscle activities, ie, RMMA, single short-burst, and clenching episodes, occur in relation to gastroesophageal reflux mainly in the supine position.

DistMap: a toolkit for distributed short read mapping on a Hadoop cluster.

PubMed

Pandey, Ram Vinay; Schlötterer, Christian

2013-01-01

With the rapid and steady increase of next generation sequencing data output, the mapping of short reads has become a major data analysis bottleneck. On a single computer, it can take several days to map the vast quantity of reads produced from a single Illumina HiSeq lane. In an attempt to ameliorate this bottleneck we present a new tool, DistMap - a modular, scalable and integrated workflow to map reads in the Hadoop distributed computing framework. DistMap is easy to use, currently supports nine different short read mapping tools and can be run on all Unix-based operating systems. It accepts reads in FASTQ format as input and provides mapped reads in a SAM/BAM format. DistMap supports both paired-end and single-end reads thereby allowing the mapping of read data produced by different sequencing platforms. DistMap is available from http://code.google.com/p/distmap/

DistMap: A Toolkit for Distributed Short Read Mapping on a Hadoop Cluster

PubMed Central

Pandey, Ram Vinay; Schlötterer, Christian

2013-01-01

With the rapid and steady increase of next generation sequencing data output, the mapping of short reads has become a major data analysis bottleneck. On a single computer, it can take several days to map the vast quantity of reads produced from a single Illumina HiSeq lane. In an attempt to ameliorate this bottleneck we present a new tool, DistMap - a modular, scalable and integrated workflow to map reads in the Hadoop distributed computing framework. DistMap is easy to use, currently supports nine different short read mapping tools and can be run on all Unix-based operating systems. It accepts reads in FASTQ format as input and provides mapped reads in a SAM/BAM format. DistMap supports both paired-end and single-end reads thereby allowing the mapping of read data produced by different sequencing platforms. DistMap is available from http://code.google.com/p/distmap/ PMID:24009693

Mechanisms limiting the performance of large grain polycrystalline silicon solar cells

NASA Technical Reports Server (NTRS)

Culik, J. S.; Alexander, P.; Dumas, K. A.; Wohlgemuth, J. W.

1984-01-01

The open-circuit voltage and short-circuit current of large-grain (1 to 10 mm grain diameter) polycrystalline silicon solar cells is determined by the minority-carrier diffusion length within the bulk of the grains. This was demonstrated by irradiating polycrystalline and single-crystal (Czochralski) silicon solar cells with 1 MeV electrons to reduce their bulk lifetime. The variation of short-circuit current with minority-carrier diffusion length for the polycrystalline solar cells is identical to that of the single-crystal solar cells. The open-circuit voltage versus short-circuit current characteristic of the polycrystalline solar cells for reduced diffusion lengths is also identical to that of the single-crystal solar cells. The open-circuit voltage of the polycrystalline solar cells is a strong function of quasi-neutral (bulk) recombination, and is reduced only slightly, if at all, by grain-boundary recombination.

Single molecule real-time (SMRT) sequencing comes of age: applications and utilities for medical diagnostics

PubMed Central

Ardui, Simon; Ameur, Adam; Vermeesch, Joris R; Hestand, Matthew S

2018-01-01

Abstract Short read massive parallel sequencing has emerged as a standard diagnostic tool in the medical setting. However, short read technologies have inherent limitations such as GC bias, difficulties mapping to repetitive elements, trouble discriminating paralogous sequences, and difficulties in phasing alleles. Long read single molecule sequencers resolve these obstacles. Moreover, they offer higher consensus accuracies and can detect epigenetic modifications from native DNA. The first commercially available long read single molecule platform was the RS system based on PacBio's single molecule real-time (SMRT) sequencing technology, which has since evolved into their RSII and Sequel systems. Here we capsulize how SMRT sequencing is revolutionizing constitutional, reproductive, cancer, microbial and viral genetic testing. PMID:29401301

The balanced scorecard: sustainable performance assessment for forensic laboratories.

PubMed

Houck, Max; Speaker, Paul J; Fleming, Arron Scott; Riley, Richard A

2012-12-01

The purpose of this article is to introduce the concept of the balanced scorecard into the laboratory management environment. The balanced scorecard is a performance measurement matrix designed to capture financial and non-financial metrics that provide insight into the critical success factors for an organization, effectively aligning organization strategy to key performance objectives. The scorecard helps organizational leaders by providing balance from two perspectives. First, it ensures an appropriate mix of performance metrics from across the organization to achieve operational excellence; thereby the balanced scorecard ensures that no single or limited group of metrics dominates the assessment process, possibly leading to long-term inferior performance. Second, the balanced scorecard helps leaders offset short term performance pressures by giving recognition and weight to long-term laboratory needs that, if not properly addressed, might jeopardize future laboratory performance. Copyright © 2012 Forensic Science Society. Published by Elsevier Ireland Ltd. All rights reserved.

[Gens Rulandica-Hungarian connections of a famous German family of physicians].

PubMed

Wix, G

2000-01-01

The Ruland family of German origin played an important role both in Hungarian and European medical history. Being a rather numerous family, and moreover, due to their habit of preferring to give the same first names to their children and because they worked in a relatively short period (ca. between 1550 and 1650), researchers often confuse one Ruland with the other. The present paper based on source-criticism, makes successful attempts to put the genealogy in order, presenting the history of the family, giving detailed biographies of each single Ruland and bringing together the bibliography of their works as well. As a result of her efforts the author puts a new light on the biographical data of the best known Ruland, namely of John David and at the same time she revisits the activity of John Ruland, who lived and worked in Hungary.

Optimized gene editing technology for Drosophila melanogaster using germ line-specific Cas9.

PubMed

Ren, Xingjie; Sun, Jin; Housden, Benjamin E; Hu, Yanhui; Roesel, Charles; Lin, Shuailiang; Liu, Lu-Ping; Yang, Zhihao; Mao, Decai; Sun, Lingzhu; Wu, Qujie; Ji, Jun-Yuan; Xi, Jianzhong; Mohr, Stephanie E; Xu, Jiang; Perrimon, Norbert; Ni, Jian-Quan

2013-11-19

The ability to engineer genomes in a specific, systematic, and cost-effective way is critical for functional genomic studies. Recent advances using the CRISPR-associated single-guide RNA system (Cas9/sgRNA) illustrate the potential of this simple system for genome engineering in a number of organisms. Here we report an effective and inexpensive method for genome DNA editing in Drosophila melanogaster whereby plasmid DNAs encoding short sgRNAs under the control of the U6b promoter are injected into transgenic flies in which Cas9 is specifically expressed in the germ line via the nanos promoter. We evaluate the off-targets associated with the method and establish a Web-based resource, along with a searchable, genome-wide database of predicted sgRNAs appropriate for genome engineering in flies. Finally, we discuss the advantages of our method in comparison with other recently published approaches.

Experimental quantum key distribution at 1.3 gigabit-per-second secret-key rate over a 10 dB loss channel

NASA Astrophysics Data System (ADS)

Zhang, Zheshen; Chen, Changchen; Zhuang, Quntao; Wong, Franco N. C.; Shapiro, Jeffrey H.

2018-04-01

Quantum key distribution (QKD) enables unconditionally secure communication ensured by the laws of physics, opening a promising route to security infrastructure for the coming age of quantum computers. QKD’s demonstrated secret-key rates (SKRs), however, fall far short of the gigabit-per-second rates of classical communication, hindering QKD’s widespread deployment. QKD’s low SKRs are largely due to existing single-photon-based protocols’ vulnerability to channel loss. Floodlight QKD (FL-QKD) boosts SKR by transmitting many photons per encoding, while offering security against collective attacks. Here, we report an FL-QKD experiment operating at a 1.3 Gbit s‑1 SKR over a 10 dB loss channel. To the best of our knowledge, this is the first QKD demonstration that achieves a gigabit-per-second-class SKR, representing a critical advance toward high-rate QKD at metropolitan-area distances.

Efficient nanosecond photoluminescence from infrared PbS quantum dots coupled to plasmonic nanoantennas

DOE PAGES

Akselrod, Gleb M.; Weidman, Mark C.; Li, Ying; ...

2016-09-13

Infrared (IR) light sources with high modulation rates are critical components for on-chip optical communications. Lead-based colloidal quantum dots are promising nonepitaxial materials for use in IR light-emitting diodes, but their slow photoluminescence lifetime is a serious limitation. Here we demonstrate coupling of PbS quantum dots to colloidal plasmonic nanoantennas based on film-coupled metal nanocubes, resulting in a dramatic 1300-fold reduction in the emission lifetime from the microsecond to the nanosecond regime. This lifetime reduction is primarily due to a 1100-fold increase in the radiative decay rate owing to the high quantum yield (65%) of the antenna. The short emissionmore » lifetime is accompanied by high antenna quantum efficiency and directionality. Lastly, this nonepitaxial platform points toward GHz frequency, electrically modulated, telecommunication wavelength light-emitting diodes and single-photon sources.« less

The unusual dynamics of parasite actin result from isodesmic polymerization

PubMed Central

Skillman, Kristen M.; Ma, Christopher I.; Fremont, Daved H.; Diraviyam, Karthikeyan; Cooper, John A.; Sept, David; Sibley, L. David

2013-01-01

Previous reports have indicated that parasite actins are short and inherently unstable, despite being required for motility. Here, we re-examine the polymerization properties of actin in Toxoplasma gondii (TgACTI), unexpectedly finding that it exhibits isodesmic polymerization in contrast to the conventional nucleation-elongation process of all previously studied actins from both eukaryotes and bacteria. TgACTI polymerization kinetics lacks both a lag phase and critical concentration, normally characteristic of actins. Unique among actins, the kinetics of assembly can be fit with a single set of rate constants for all subunit interactions, without need for separate nucleation and elongation rates. This isodesmic model accurately predicts the assembly, disassembly, and the size distribution of TgACTI filaments in vitro, providing a mechanistic explanation for actin dynamics in vivo. Our findings expand the repertoire of mechanisms by which actin polymerization is governed and offer clues about the evolution of self-assembling, stabilized protein polymers. PMID:23921463

A technique for extracting blood samples from mice in fire toxicity tests

NASA Technical Reports Server (NTRS)

Bucci, T. J.; Hilado, C. J.; Lopez, M. T.

1976-01-01

The extraction of adequate blood samples from moribund and dead mice has been a problem because of the small quantity of blood in each animal and the short time available between the animals' death and coagulation of the blood. These difficulties are particularly critical in fire toxicity tests because removal of the test animals while observing proper safety precautions for personnel is time-consuming. Techniques for extracting blood samples from mice were evaluated, and a technique was developed to obtain up to 0.8 ml of blood from a single mouse after death. The technique involves rapid exposure and cutting of the posterior vena cava and accumulation of blood in the peritoneal space. Blood samples of 0.5 ml or more from individual mice have been consistently obtained as much as 16 minutes after apparent death. Results of carboxyhemoglobin analyses of blood appeared reproducible and consistent with carbon monoxide concentrations in the exposure chamber.

Switch failure diagnosis based on inductor current observation for boost converters

NASA Astrophysics Data System (ADS)

Jamshidpour, E.; Poure, P.; Saadate, S.

2016-09-01

Face to the growing number of applications using DC-DC power converters, the improvement of their reliability is subject to an increasing number of studies. Especially in safety critical applications, designing fault-tolerant converters is becoming mandatory. In this paper, a switch fault-tolerant DC-DC converter is studied. First, some of the fastest Fault Detection Algorithms (FDAs) are recalled. Then, a fast switch FDA is proposed which can detect both types of failures; open circuit fault as well as short circuit fault can be detected in less than one switching period. Second, a fault-tolerant converter which can be reconfigured under those types of fault is introduced. Hardware-In-the-Loop (HIL) results and experimental validations are given to verify the validity of the proposed switch fault-tolerant approach in the case of a single switch DC-DC boost converter with one redundant switch.

Satellite Observations of the Effect of Natural and Anthropogenic Aerosols on Clouds

NASA Technical Reports Server (NTRS)

Kaufman, Yoram J.

2006-01-01

Our knowledge of atmospheric aerosols (smoke, pollution, dust or sea salt particles, small enough to be suspended in the air), their evolution, composition, variability in space and time and interaction with clouds and precipitation is still lacking despite decades of research. Understanding the global aerosol system is critical to quantifying anthropogenic climate change, to determine climate sensitivity from observations and to understand the hydrological cycle. While a single instrument was used to demonstrate 50 years ago that the global CO2 levels are rising, posing threat of global warming, we need an array of satellites and field measurements coupled with chemical transport models to understand the global aerosol system. This complexity of the aerosol problem results from their short lifetime (1 week) and variable chemical composition. A new generation of satellites provides exciting opportunities to measure the global distribution of aerosols, distinguishing natural from anthropogenic aerosol and measuring their interaction with clouds and climate.

TLR expression and NK cell activation after human yellow fever vaccination.

PubMed

Neves, Patrícia Cristina da Costa; Matos, Denise Cristina de Souza; Marcovistz, Rugimar; Galler, Ricardo

2009-09-18

The yellow fever vaccine is very effective with a single injection conferring protection for at least 10 years. Recent evidence suggests that the innate immune cells activated through Toll-like receptors (TLRs), are critical determinants of the robustness of the adaptive response. Therefore, we investigated the NK cell status in eight healthy volunteers after vaccination with YF 17DD virus. Shortly after vaccination, we observed increased expression of TLR-3 and TLR-9 in NK cells and markers such as CD69, HLA-DP-DQ-DR, CD38 and CD16. The up-regulation of CD69 was positively correlated with the presence of TLRs throughout the post-vaccination period and the circulating IFN-gamma was significantly augmented. These results suggest that TLRs may play an important role in NK cell activation during the immune response to vaccination, indicating a potential role for NK cells in helping the development of long-lasting protective memory.

Electrical and magnetic properties of conductive Cu-based coated conductors

NASA Astrophysics Data System (ADS)

Aytug, T.; Paranthaman, M.; Thompson, J. R.; Goyal, A.; Rutter, N.; Zhai, H. Y.; Gapud, A. A.; Ijaduola, A. O.; Christen, D. K.

2003-11-01

The development of YBa2Cu3O7-δ (YBCO)-based coated conductors for electric power applications will require electrical and thermal stabilization of the high-temperature superconducting (HTS) coating. In addition, nonmagnetic tape substrates are an important factor in order to reduce the ferromagnetic hysteresis energy loss in ac applications. We report progress toward a conductive buffer layer architecture on biaxially textured nonmagnetic Cu tapes to electrically couple the HTS layer to the underlying metal substrate. A protective Ni overlayer, followed by a single buffer layer of La0.7Sr0.3MnO3, was employed to avoid Cu diffusion and to improve oxidation resistance of the substrate. Property characterizations of YBCO films on short prototype samples revealed self-field critical current density (Jc) values exceeding 2×106 A/cm2 at 77 K and good electrical connectivity. Magnetic hysteretic loss due to Ni overlayer was also investigated.

Demonstration of Cascaded Modulator-Chicane Microbunching of a Relativistic Electron Beam

DOE PAGES

Sudar, N.; Musumeci, P.; Gadjev, I.; ...

2018-03-15

Here, we present results of an experiment showing the first successful demonstration of a cascaded microbunching scheme. Two modulator-chicane prebunchers arranged in series and a high power mid-IR laser seed are used to modulate a 52 MeV electron beam into a train of sharp microbunches phase locked to the external drive laser. This configuration is shown to greatly improve matching of the beam into the small longitudinal phase space acceptance of short-wavelength accelerators. We demonstrate trapping of nearly all (96%) of the electrons in a strongly tapered inverse free-electron laser accelerator, with an order-of-magnitude reduction in injection losses compared tomore » the classical single-buncher scheme. These results represent a critical advance in laser-based longitudinal phase space manipulations and find application in high gradient advanced acceleration as well as in high peak and average power coherent radiation sources.« less

Mental Health on the Go: Effects of a Gamified Attention Bias Modification Mobile Application in Trait Anxious Adults.

PubMed

Dennis, Tracy A; O'Toole, Laura

2014-09-01

Interest in the use of mobile technology to deliver mental health services has grown in light of the economic and practical barriers to treatment. Yet, research on alternative delivery strategies that are more affordable, accessible, and engaging is in its infancy. Attention bias modification training (ABMT), has potential to reduce treatment barriers as a mobile intervention for stress and anxiety, but the degree to which ABMT can be embedded in a mobile gaming format and its potential for transfer of benefits is unknown. The present study examined effects of a gamified ABMT mobile application in highly trait anxious participants ( N = 78). A single session of the active compared to placebo training reduced subjective anxiety and observed stress reactivity. Critically, the long (45 minutes) but not short (25 minutes) active training condition reduced the core cognitive process implicated in ABMT (threat bias) as measured by an untrained, gold-standard protocol.

Frictional behaviour and evolution of rough faults in limestone

NASA Astrophysics Data System (ADS)

Harbord, C. W. A.; Nielsen, S. B.; De Paola, N.; Holdsworth, R.

2017-12-01

Fault roughness is an important parameter which influences the frictional behaviour of seismically active faults, in particular the nucleation stage of earthquakes. Here we investigate frictional sliding and stability of roughened micritic limestone surfaces from the seismogenic layer in Northern-Central Apennines of Italy. Samples are roughened using #60, #220 and #400 grit and deformed in a direct shear configuration at conditions typical of the shallow upper crust (15-60 MPa normal stress). We perform velocity steps between 0.01-1 μm s-1 to obtain rate-and-state friction parameters a, b and L. At low normal stress conditions (30 MPa) and at displacements of <3-4mm there is a clear 2 state evolution of friction with two state parameters, b1 and b2, and accompanying critical slip distances L1 and L2 for all roughnesses. In some cases, on smooth faults (#400 grit), the short term evolution leads to silent slow instability which is modulated by the second state evolution. With increasing slip displacement (>2-4 mm) friction can be modelled with a single state parameter, b, as the short frictional evolution disappears. The longer term state evolution, b2, gives negative values of b, reminiscent of plastic creep experiments at high temperature, reaching a steady state at 3-4 mm displacement. Microstructural observations reveal shiny surfaces decorated by nanometric gouge particles with variable porosity. When normal stress is increased, rough faults (#60 grit) revert to a single state evolution with positive values of b, whilst smoother faults (#220 & #400 grit) retain a two state evolution with negative b2 values. These observations suggest that on carbonate hosted faults sliding may be controlled by plastic processes which can lead to slow stick-slip instability, which may be supressed by frictional wear and accompanying gouge build-up.

Stem cell-derived models to improve mechanistic understanding and prediction of human drug-induced liver injury.

PubMed

Goldring, Christopher; Antoine, Daniel J; Bonner, Frank; Crozier, Jonathan; Denning, Chris; Fontana, Robert J; Hanley, Neil A; Hay, David C; Ingelman-Sundberg, Magnus; Juhila, Satu; Kitteringham, Neil; Silva-Lima, Beatriz; Norris, Alan; Pridgeon, Chris; Ross, James A; Young, Rowena Sison; Tagle, Danilo; Tornesi, Belen; van de Water, Bob; Weaver, Richard J; Zhang, Fang; Park, B Kevin

2017-02-01

Current preclinical drug testing does not predict some forms of adverse drug reactions in humans. Efforts at improving predictability of drug-induced tissue injury in humans include using stem cell technology to generate human cells for screening for adverse effects of drugs in humans. The advent of induced pluripotent stem cells means that it may ultimately be possible to develop personalized toxicology to determine interindividual susceptibility to adverse drug reactions. However, the complexity of idiosyncratic drug-induced liver injury means that no current single-cell model, whether of primary liver tissue origin, from liver cell lines, or derived from stem cells, adequately emulates what is believed to occur during human drug-induced liver injury. Nevertheless, a single-cell model of a human hepatocyte which emulates key features of a hepatocyte is likely to be valuable in assessing potential chemical risk; furthermore, understanding how to generate a relevant hepatocyte will also be critical to efforts to build complex multicellular models of the liver. Currently, hepatocyte-like cells differentiated from stem cells still fall short of recapitulating the full mature hepatocellular phenotype. Therefore, we convened a number of experts from the areas of preclinical and clinical hepatotoxicity and safety assessment, from industry, academia, and regulatory bodies, to specifically explore the application of stem cells in hepatotoxicity safety assessment and to make recommendations for the way forward. In this short review, we particularly discuss the importance of benchmarking stem cell-derived hepatocyte-like cells to their terminally differentiated human counterparts using defined phenotyping, to make sure the cells are relevant and comparable between labs, and outline why this process is essential before the cells are introduced into chemical safety assessment. (Hepatology 2017;65:710-721). © 2016 by the American Association for the Study of Liver Diseases.

Configuration Studies of Personal Air Vehicles. Personal Air Vehicle and Flying Jeep Concepts: A Commentary on Promising Approaches or What Goes Around Comes Around (About Every Twenty Years)

NASA Technical Reports Server (NTRS)

Hall, David W.

2001-01-01

The NASA/Langley Personal Air Vehicle (PAV) Exploration (PAVE) and the DARPA (Defense Advanced Research Projects Agency) Dual Air/Road Transportation System (DARTS) projects were established to investigate the feasibility of creating vehicles which could replace, or at the very least augment, personal ground and air transportation schemes. This overall goal implies integrating several technology areas with practical everyday transportation requirements to design a class of vehicles which will achieve the following goals: (1) Vertical, Extremely Short, or Short Takeoff and Landing (VTOL, ESTOL, STOL) capability; (2) Operation at block speeds markedly faster than current combinations of land and air transportation, particularly in critical market areas; (3) Unit cost comparable to current luxury cars and small general aviation aircraft; (4) Excellent reliability; (5) Excellent safety; (6) Ability to integrate with existing land and air transportation systems. The conclusions of these configuration studies are summarized as follows: (1) Creation of the five assigned configurations prompted added explorations, some of which were dead-ends; (2) Some components could be common to all configurations such as avionics and dual-mode suspension schemes; (3) Single-Mode PAVs can be created by removing dual-mode-specific items; (4) Aviation history provided some intriguing starting points, as in what goes around comes around; (5) CTOL (Conventional Take-off and Landing) and STOL dual-mode PAVs look feasible with single-mode PAVs being simplifications of the dual-mode approach; (6) VTOL PAVs will require development; (7) More exotic collapsing mechanisms mechanisms need development; (8) As a teaching tool, PAVs are not yet a well-enough bounded design problem.

Lack of interaction between a new antihistamine, mizolastine, and lorazepam on psychomotor performance and memory in healthy volunteers.

PubMed

Patat, A; Perault, M C; Vandel, B; Ulliac, N; Zieleniuk, I; Rosenzweig, P

1995-01-01

1. The possible interaction between a new H1 antihistamine, mizolastine, and lorazepam was assessed in a randomised, double-blind, cross-over, placebo-controlled study involving 16 healthy young male volunteers who received mizolastine 10 mg or placebo once daily for 8 days with a 1 week wash-out interval. The interaction of mizolastine, at steady-state, with a single oral dose of lorazepam or placebo was assessed on days 6 or 8 of each treatment period. 2. Psychomotor performance and cognitive function were evaluated using objective tests (critical flicker fusion threshold, choice reaction time, tapping, arithmetic calculation, body sway) and self-ratings (visual analogue scale, ARCI) before and at 2, 4, 6 and 8 h after dosing. Short-term memory (Sternberg memory scanning immediate free recall of a word list) and long-term memory (delayed free recall and recognition of words and pictures) were assessed before and at 3 h after dosing. Pharmacodynamic interactions were evaluated by repeated measures ANOVA in a 2 x 2 factorial interaction model. 3. Mizolastine, 10 mg once daily, at steady-state, was devoid of sedation and detrimental effect on skilled performance and memory. 4. In contrast, a single 2 mg dose of lorazepam produced marked impairment of psychomotor performance, cognitive functions (significant reduction in flicker fusion threshold, tapping and arithmetic calculation and increase in reaction times and body sway) and subjective sedation from 2 to 8 h after dosing. In addition, lorazepam induced an anterograde amnesia, characterised by a decrease in delayed free recall and recognition, and a deficit in short term memory.(ABSTRACT TRUNCATED AT 250 WORDS)

Effective theory and breakdown of conformal symmetry in a long-range quantum chain

NASA Astrophysics Data System (ADS)

Lepori, L.; Vodola, D.; Pupillo, G.; Gori, G.; Trombettoni, A.

2016-11-01

We deal with the problem of studying the symmetries and the effective theories of long-range models around their critical points. A prominent issue is to determine whether they possess (or not) conformal symmetry (CS) at criticality and how the presence of CS depends on the range of the interactions. To have a model, both simple to treat and interesting, where to investigate these questions, we focus on the Kitaev chain with long-range pairings decaying with distance as power-law with exponent α. This is a quadratic solvable model, yet displaying non-trivial quantum phase transitions. Two critical lines are found, occurring respectively at a positive and a negative chemical potential. Focusing first on the critical line at positive chemical potential, by means of a renormalization group approach we derive its effective theory close to criticality. Our main result is that the effective action is the sum of two terms: a Dirac action SD, found in the short-range Ising universality class, and an "anomalous" CS breaking term SAN. While SD originates from low-energy excitations in the spectrum, SAN originates from the higher energy modes where singularities develop, due to the long-range nature of the model. At criticality SAN flows to zero for α > 2, while for α < 2 it dominates and determines the breakdown of the CS. Out of criticality SAN breaks, in the considered approximation, the effective Lorentz invariance (ELI) for every finite α. As α increases such ELI breakdown becomes less and less pronounced and in the short-range limit α → ∞ the ELI is restored. In order to test the validity of the determined effective theory, we compared the two-fermion static correlation functions and the von Neumann entropy obtained from them with the ones calculated on the lattice, finding agreement. These results explain two observed features characteristic of long-range models, the hybrid decay of static correlation functions within gapped phases and the area-law violation for the von Neumann entropy. The proposed scenario is expected to hold in other long-range models displaying quasiparticle excitations in ballistic regime. From the effective theory one can also see that new phases emerge for α < 1. Finally we show that at every finite α the critical exponents, defined as for the short-range (α → ∞) model, are not altered. This also shows that the long-range paired Kitaev chain provides an example of a long-range model in which the value of α where the CS is broken does not coincide with the value at which the critical exponents start to differ from the ones of the corresponding short-range model. At variance, for the second critical line, having negative chemical potential, only SAN (SD) is present for 1 < α < 2 (for α > 2). Close to this line, where the minimum of the spectrum coincides with the momentum where singularities develop, the critical exponents change where CS is broken.

Temperature field analysis of single layer TiO2 film components induced by long-pulse and short-pulse lasers.

PubMed

Wang, Bin; Zhang, Hongchao; Qin, Yuan; Wang, Xi; Ni, Xiaowu; Shen, Zhonghua; Lu, Jian

2011-07-10

To study the differences between the damaging of thin film components induced by long-pulse and short-pulse lasers, a model of single layer TiO(2) film components with platinum high-absorptance inclusions was established. The temperature rises of TiO(2) films with inclusions of different sizes and different depths induced by a 1 ms long-pulse and a 10 ns short-pulse lasers were analyzed based on temperature field theory. The results show that there is a radius range of inclusions that corresponds to high temperature rises. Short-pulse lasers are more sensitive to high-absorptance inclusions and long-pulse lasers are more easily damage the substrate. The first-damage decision method is drawn from calculations. © 2011 Optical Society of America

Understanding the Progenitors of Short Gamma-Ray Bursts via their Host Galaxies: A Pilot Study

NASA Astrophysics Data System (ADS)

Cenko, S. Brad

2014-08-01

While massive star core-collapse is known to power long-duration gamma-ray bursts (GRBs), the origin of short GRBs remains unconfirmed. Studies of the host galaxies of short GRBs provide critical constraints on their progenitors, particularly if (as expected) short GRBs result from the neutron star mergers. Here we request deep Keck/LRIS imaging of short GRBs lacking securely identified hosts. By constraining the fraction of events that appear to have been 'kicked' out of their host galaxy in a more unbiased manner than past efforts, we aim to infer fundamental properties about the formation and evolution of binary neutron star systems.

Sustaining critical care: using evidence-based simulation to evaluate ICU management policies.

PubMed

Mahmoudian-Dehkordi, Amin; Sadat, Somayeh

2017-12-01

Intensive Care Units (ICU) are costly yet critical hospital departments that should be available to care for patients needing highly specialized critical care. Shortage of ICU beds in many regions of the world and the constant fire-fighting to make these beds available through various ICU management policies motivated this study. The paper discusses the application of a generic system dynamics model of emergency patient flow in a typical hospital, populated with empirical evidence found in the medical and hospital administration literature, to explore the dynamics of intended and unintended consequences of such ICU management policies under a natural disaster crisis scenario. ICU management policies that can be implemented by a single hospital on short notice, namely premature transfer from ICU, boarding in ward, and general ward admission control, along with their possible combinations, are modeled and their impact on managerial and health outcome measures are investigated. The main insight out of the study is that the general ward admission control policy outperforms the rest of ICU management policies under such crisis scenarios with regards to reducing total mortality, which is counter intuitive for hospital administrators as this policy is not very effective at alleviating the symptoms of the problem, namely high ED and ICU occupancy rates that are closely monitored by hospital management particularly in times of crisis. A multivariate sensitivity analysis on parameters with diverse range of values in the literature found the superiority of the general ward admission control to hold true in every scenario.

A Single Brief Burst Induces GluR1-Dependent Associative Short-Term Potentiation: A Potential Mechanism for Short-Term Memory

ERIC Educational Resources Information Center

Erickson, Martha A.; Maramara, Lauren A.; Lisman, John

2010-01-01

Recent work showed that short-term memory (STM) is selectively reduced in GluR1 knockout mice. This raises the possibility that a form of synaptic modification dependent on GluR1 might underlie STM. Studies of synaptic plasticity have shown that stimuli too weak to induce long-term potentiation induce short-term potentiation (STP), a phenomenon…

A category-specific advantage for numbers in verbal short-term memory: evidence from semantic dementia.

PubMed

Jefferies, Elizabeth; Patterson, Karalyn; Jones, Roy W; Bateman, David; Lambon Ralph, Matthew A

2004-01-01

This study explored possible reasons for the striking difference between digit span and word span in patients with semantic dementia. Immediate serial recall (ISR) of number and non-number words was examined in four patients. For every case, the recall of single-digit numbers was normal whereas the recall of non-number words was impaired relative to controls. This difference extended to multi-digit numbers, and remained even when frequency, imageability, word length, set size and size of semantic category were matched for the numbers and words. The advantage for number words also applied to the patients' reading performance. Previous studies have suggested that semantic memory plays a critical role in verbal short-term memory (STM) and reading: patients with semantic dementia show superior recall and reading of words that are still relatively well known compared to previously known but now semantically degraded words. Additional assessments suggested that this semantic locus was the basis of the patients' category-specific advantage for numbers. Comprehension was considerably better for number than non-number words. Number knowledge may be relatively preserved in semantic dementia because the cortical atrophy underlying the condition typically spares the areas of the parietal lobes thought to be crucial in numerical cognition but involves the inferolateral temporal-lobes known to support general conceptual knowledge.

The free-fall mode experiment on LISA Pathfinder: first results

NASA Astrophysics Data System (ADS)

Giusteri, Roberta; LPF Collaboration

2017-05-01

The LISA Pathfinder space mission is testing the critical experimental challenge for LISA by measuring the differential acceleration between two free-falling test masses inside a single co-orbiting spacecraft at a level of sub-femto-g for frequencies down to 0.1mHz. In LPF it is necessary that one test mass (TM) is electrostatically forced to follow the orbit of the other TM. This force represents a noise source in differential acceleration at frequencies below 1mHz. The free-fall mode experiment has been performed in order to reduce this source of noise: the actuation is limited to short impulses on one TM, so that it is in free fall between two successive kicks, while the other TM is drag-free. The free-fall mode thus provides a different technique for measuring the differential TM acceleration without the added force noise and calibration issues introduced by the actuator. Data analysis challenge is related to the presence of the kicks: they represent a high-noise contribution and need to be removed, thus leaving short gaps in data. This article presents preliminary data of the LPF free-fall measurement campaign and describes the three data analysis techniques developed to mitigate the presence of gaps.

The effect of lexical factors on recall from working memory: Generalizing the neighborhood size effect.

PubMed

Derraugh, Lesley S; Neath, Ian; Surprenant, Aimée M; Beaudry, Olivia; Saint-Aubin, Jean

2017-03-01

The word-length effect, the finding that lists of short words are better recalled than lists of long words, is 1 of the 4 benchmark phenomena that guided development of the phonological loop component of working memory. However, previous work has noted a confound in word-length studies: The short words used had more orthographic neighbors (valid words that can be made by changing a single letter in the target word) than long words. The confound is that words with more neighbors are better recalled than otherwise comparable words with fewer neighbors. Two experiments are reported that address criticisms of the neighborhood-size account of the word-length effect by (1) testing 2 new stimulus sets, (2) using open rather than closed pools of words, and (3) using stimuli from a language other than English. In both experiments, words from large neighborhoods were better recalled than words from small neighborhoods. The results add to the growing number of studies demonstrating the substantial contribution of long-term memory to what have traditionally been identified as working memory tasks. The data are more easily explained by models incorporating the concept of redintegration rather than by frameworks such as the phonological loop that posit decay offset by rehearsal. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Short bouts of vocalization induce long lasting fast gamma oscillations in a sensorimotor nucleus

PubMed Central

Lewandowski, Brian; Schmidt, Marc

2011-01-01

Performance evaluation is a critical feature of motor learning. In the vocal system, it requires the integration of auditory feedback signals with vocal motor commands. The network activity that supports such integration is unknown, but it has been proposed that vocal performance evaluation occurs offline. Recording from NIf, a sensorimotor structure in the avian song system, we show that short bouts of singing in adult male zebra finches (Taeniopygia guttata) induce persistent increases in firing activity and coherent oscillations in the fast gamma range (90–150 Hz). Single units are strongly phase-locked to these oscillations, which can last up to 30 s, often outlasting vocal activity by an order of magnitude. In other systems, oscillations often are triggered by events or behavioral tasks but rarely outlast the event that triggered them by more than 1 second. The present observations are the longest reported gamma oscillations triggered by an isolated behavioral event. In mammals, gamma oscillations have been associated with memory consolidation and are hypothesized to facilitate communication between brain regions. We suggest that the timing and persistent nature of NIf’s fast gamma oscillations make them well suited to facilitate the integration of auditory and vocal motor traces associated with vocal performance evaluation. PMID:21957255

Giant increase in critical current density of K xFe 2-ySe₂ single crystals

DOE PAGES

Lei, Hechang; Petrovic, C.

2011-12-28

The critical current density Jabc of K xFe 2-ySe₂ single crystals can be enhanced by more than one order of magnitude, up to ~2.1×10⁴ A/cm² by the post annealing and quenching technique. A scaling analysis reveals the universal behavior of the normalized pinning force as a function of the reduced field for all temperatures, indicating the presence of a single vortex pinning mechanism. The main pinning sources are three-dimensional (3D) point-like normal cores. The dominant vortex interaction with pinning centers is via spatial variations in critical temperature T c (“δT c pinning”).

Fluorescence quenching by TEMPO: a sub-30 A single-molecule ruler.

PubMed

Zhu, Peizhi; Clamme, Jean-Pierre; Deniz, Ashok A

2005-11-01

A series of DNA molecules labeled with 5-carboxytetramethylrhodamine (5-TAMRA) and the small nitroxide radical TEMPO were synthesized and tested to investigate whether the intramolecular quenching efficiency can be used to measure short intramolecular distances in small ensemble and single-molecule experiments. In combination with distance calculations using molecular mechanics modeling, the experimental results from steady-state ensemble fluorescence and fluorescence correlation spectroscopy measurements both show an exponential decrease in the quenching rate constant with the dye-quencher distance in the 10-30 A range. The results demonstrate that TEMPO-5-TAMRA fluorescence quenching is a promising method to measure short distance changes within single biomolecules.

On the limited recognition of inorganic surfaces by short peptides compared with antibodies.

PubMed

Artzy-Schnirman, Arbel; Abu-Shah, Enas; Dishon, Matan; Soifer, Hadas; Sivan, Yotam; Reiter, Yoram; Benhar, Itai; Sivan, Uri

2014-06-01

The vast potential applications of biomolecules that bind inorganic surfaces led mostly to the isolation of short peptides that target selectively specific materials. The demonstrated differential affinity toward certain surfaces created the impression that the recognition capacity of short peptides may match that of rigid biomolecules. In the following, we challenge this view by comparing the capacity of antibody molecules to discriminate between the (100) and (111A) facets of a gallium arsenide semiconductor crystal with the capacity of short peptides to do the same. Applying selection from several peptide and single chain phage display libraries, we find a number of antibody molecules that bind preferentially a given crystal facet but fail to isolate, in dozens of attempts, a single peptide capable of such recognition. The experiments underscore the importance of rigidity to the recognition of inorganic flat targets and therefore set limitations on potential applications of short peptides in biomimetics. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd.

Effects of long and short simulated flights on the saccadic eye movement velocity of aviators.

PubMed

Di Stasi, Leandro L; McCamy, Michael B; Martinez-Conde, Susana; Gayles, Ellis; Hoare, Chad; Foster, Michael; Catena, Andrés; Macknik, Stephen L

2016-01-01

Aircrew fatigue is a major contributor to operational errors in civil and military aviation. Objective detection of pilot fatigue is thus critical to prevent aviation catastrophes. Previous work has linked fatigue to changes in oculomotor dynamics, but few studies have studied this relationship in critical safety environments. Here we measured the eye movements of US Marine Corps combat helicopter pilots before and after simulated flight missions of different durations.We found a decrease in saccadic velocities after long simulated flights compared to short simulated flights. These results suggest that saccadic velocity could serve as a biomarker of aviator fatigue.

Impact of duration of critical illness on the adrenal glands of human intensive care patients.

PubMed

Boonen, Eva; Langouche, Lies; Janssens, Thomas; Meersseman, Philippe; Vervenne, Hilke; De Samblanx, Emilie; Pironet, Zoë; Van Dyck, Lisa; Vander Perre, Sarah; Derese, Inge; Van den Berghe, Greet

2014-11-01

Adrenal insufficiency is considered to be prevalent during critical illness, although the pathophysiology, diagnostic criteria, and optimal therapeutic strategy remain controversial. During critical illness, reduced cortisol breakdown contributes substantially to elevated plasma cortisol and low plasma ACTH concentrations. Because ACTH has a trophic impact on the adrenal cortex, we hypothesized that with a longer duration of critical illness, subnormal ACTH adrenocortical stimulation predisposes to adrenal insufficiency. Adrenal glands were harvested 24 hours or sooner after death from 13 long intensive care unit (ICU)-stay patients, 27 short ICU-stay patients, and 13 controls. Prior glucocorticoid treatment was excluded. MAIN OUTCOME AND MEASURE(S): Microscopic adrenocortical zonational structure was evaluated by hematoxylin and eosin staining. The amount of adrenal cholesterol esters was determined by Oil-Red-O staining, and mRNA expression of ACTH-regulated steroidogenic enzymes was quantified. The adrenocortical zonational structure was disturbed in patients as compared with controls (P < .0001), with indistinguishable adrenocortical zones present only in long ICU-stay patients (P = .003 vs. controls). Adrenal glands from long ICU-stay patients, but not those of short ICU-stay patients, contained 21% less protein (P = .03) and 9% more fluid (P = .01) than those from controls, whereas they tended to weigh less for comparable adrenal surface area. There was 78% less Oil-Red-O staining in long ICU-stay patients than in controls and in short-stay patients (P = .03), the latter similar to controls (P = .31). The mRNA expression of melanocortin 2 receptor, scavenger-receptor class B, member 1, 3-hydroxy-3-methylglutaryl-CoA reductase, steroidogenic acute regulatory protein, and cytochrome P450 cholesterol side-chain cleavage enzyme was at least 58% lower in long ICU-stay patients than in controls (all P ≤ .03) and of melanocortin 2 receptor, scavenger-receptor class B, member 1, steroidogenic acute regulatory protein, and cytochrome P450 cholesterol side-chain cleavage enzyme at least 53% lower than in short ICU-stay patients (all P ≤ .04), whereas gene expression in short ICU-stay patients was similar to controls. Lipid depletion and reduced ACTH-regulated gene expression in prolonged critical illness suggest that sustained lack of ACTH may contribute to the risk of adrenal insufficiency in long-stay ICU patients.

Relativistic and the first sectorial harmonics corrections in the critical inclination

NASA Astrophysics Data System (ADS)

Rahoma, W. A.; Khattab, E. H.; Abd El-Salam, F. A.

2014-05-01

The problem of the critical inclination is treated in the Hamiltonian framework taking into consideration post-Newtonian corrections as well as the main correction term of sectorial harmonics for an earth-like planet. The Hamiltonian is expressed in terms of Delaunay canonical variables. A canonical transformation is applied to eliminate short period terms. A modified critical inclination is obtained due to relativistic and the first sectorial harmonics corrections.

Detecting Intramolecular Conformational Dynamics of Single Molecules in Short Distance Range with Sub-Nanometer Sensitivity

PubMed Central

Zhou, Ruobo; Kunzelmann, Simone; Webb, Martin R.; Ha, Taekjip

2011-01-01

Single molecule detection is useful for characterizing nanoscale objects such as biological macromolecules, nano-particles and nano-devices with nano-meter spatial resolution. Fluorescence resonance energy transfer (FRET) is widely used as a single-molecule assay to monitor intramolecular dynamics in the distance range of 3–8 nm. Here we demonstrate that self-quenching of two rhodamine derivatives can be used to detect small conformational dynamics corresponding to sub-nanometer distance changes in a FRET-insensitive short range at the single molecule level. A ParM protein mutant labeled with two rhodamines works as a single molecule ADP sensor which has 20 times brighter fluorescence signal in the ADP bound state than the unbound state. Single molecule time trajectories show discrete transitions between fluorescence on and off states that can be directly ascribed to ADP binding and dissociation events. The conformational changes observed with 20:1 contrast are only 0.5 nm in magnitude and are between crystallographic distances of 1.6 nm and 2.1 nm, demonstrating exquisite sensitivity to short distance scale changes. The systems also allowed us to gain information on the photophysics of self-quenching induced by rhodamine stacking: (1) photobleaching of either of the two rhodamines eliminates quenching of the other rhodamine fluorophore and (2) photobleaching from the highly quenched, stacked state is only two-fold slower than from the unstacked state. PMID:22023515

Re/Learning Student Teaching Supervision: A Co/Autoethnographic Self-Study

ERIC Educational Resources Information Center

Butler, Brandon M.; Diacopoulos, Mark M.

2016-01-01

This article documents the critical friendship of an experienced teacher educator and a doctoral student through our joint exploration of student teaching supervision. By adopting a co/autoethnographic approach, we learned from biographical and contemporaneous critical incidents that informed short- and long-term practices. In particular, we…

Globalizing English through Intercultural Critical Literacy

ERIC Educational Resources Information Center

Myers, Jamie; Eberfors, Fredrik

2010-01-01

This article examines the construction of an intercultural critical literacy practice in a Web-based discussion forum as one way to globalize interpretive practices within the English classroom. English education students in the United States and Sweden discussed a short story over a period of three weeks. The analysis of the students' postings…

Single-Photon-Triggered Quantum Phase Transition

NASA Astrophysics Data System (ADS)

Lü, Xin-You; Zheng, Li-Li; Zhu, Gui-Lei; Wu, Ying

2018-06-01

We propose a hybrid quantum model combining cavity QED and optomechanics, which allows the occurrence of an equilibrium superradiant quantum phase transition (QPT) triggered by a single photon. This single-photon-triggered QPT exists in the cases of both ignoring and including the so-called A2 term; i.e., it is immune to the no-go theorem. It originally comes from the photon-dependent quantum criticality featured by the proposed hybrid quantum model. Moreover, a reversed superradiant QPT is induced by the competition between the introduced A2 term and the optomechanical interaction. This work offers an approach to manipulate QPT with a single photon, which should inspire the exploration of single-photon quantum-criticality physics and the engineering of new single-photon quantum devices.

Femtosecond Photon-Counting Receiver

NASA Technical Reports Server (NTRS)

Krainak, Michael A.; Rambo, Timothy M.; Yang, Guangning; Lu, Wei; Numata, Kenji

2016-01-01

An optical correlation receiver is described that provides ultra-precise distance and/or time/pulse-width measurements even for weak (single photons) and short (femtosecond) optical signals. A new type of optical correlation receiver uses a fourth-order (intensity) interferometer to provide micron distance measurements even for weak (single photons) and short (femtosecond) optical signals. The optical correlator uses a low-noise-integrating detector that can resolve photon number. The correlation (range as a function of path delay) is calculated from the variance of the photon number of the difference of the optical signals on the two detectors. Our preliminary proof-of principle data (using a short-pulse diode laser transmitter) demonstrates tens of microns precision.

Femtosecond Photon-Counting Receiver

NASA Technical Reports Server (NTRS)

Krainak, Michael A.; Rambo, Timothy M.; Yang, Guangning; Lu, Wei; Numata, Kenji

2016-01-01

An optical correlation receiver is described that provides ultra-precise distance and/or time-pulse-width measurements even for weak (single photons) and short (femtosecond) optical signals. A new type of optical correlation receiver uses a fourth-order (intensity) interferometer to provide micron distance measurements even for weak (single photons) and short (femtosecond) optical signals. The optical correlator uses a low-noise-integrating detector that can resolve photon number. The correlation (range as a function of path delay) is calculated from the variance of the photon number of the difference of the optical signals on the two detectors. Our preliminary proof-of principle data (using a short-pulse diode laser transmitter) demonstrates tens of microns precision.

The Impact of Blog-Style Writing on Student Learning Outcomes: A Pilot Study

ERIC Educational Resources Information Center

Hansen, Holley E.

2016-01-01

Two major goals of teaching include educating students to communicate effectively and encouraging students to critically engage with information. To what extent can student blog writing help us achieve these goals? In this pilot study, I analyze how short "blog-style" writing assignments compare to more traditional short research essays…

In Their Own Words: Assessing Global Citizenship in a Short-Term Study-Abroad Program in Bangladesh

ERIC Educational Resources Information Center

Gambino, Giacomo; Hashim, S. Mohsin

2016-01-01

The article examines whether short-term study-abroad (STSA) experiences can cultivate the cultural understandings and ethical commitments entailed by a cosmopolitan civic education. We examine students' critical reflections on their participation in a two-week study-abroad program titled "Climate Change and Sustainable Development in…

Novels and Short Stories about Work: An Annotated Bibliography.

ERIC Educational Resources Information Center

Koziol, Kenneth G.

This document contains an annotated list of novels and short stories written in English or available in translation that teachers can use to help students at the secondary and college levels think critically about the world of work. The categories by which they are organized are as follows: agriculture, business, career (choices, paths, and…

Central additive effect of Ginkgo biloba and Rhodiola rosea on psychomotor vigilance task and short-term working memory accuracy.

PubMed

Al-Kuraishy, Hayder M

2016-01-01

The present study investigates the effect of combined treatment with Ginkgo biloba and/or Rhodiola rosea on psychomotor vigilance task (PVT) and short-term working memory accuracy. A total number of 112 volunteers were enrolled to study the effect of G. biloba and R. rosea on PVT and short-term working memory accuracy as compared to placebo effects, the central cognitive effect was assessed by critical flicker-fusion frequency, PVT, and computerized N-back test. Placebo produced no significant effects on all neurocognitive tests measure P > 0.05 in normal healthy volunteers, G. biloba or R. rosea improve PVT and low to moderate working memory accuracy, The combined effect of R. rosea and G. biloba leading to more significant effect on PVT, all levels of short-term working memory accuracy and critical fusion versus flicker P < 0.01, more than of G. biloba or R. rosea when they used alone. The combined effect of R. rosea and G. biloba leading to a more significant effect on cognitive function than either G. biloba or R. rosea when they used alone.

Not spreading in reverse: The dewetting of a liquid film into a single drop

PubMed Central

Edwards, Andrew M. J.; Ledesma-Aguilar, Rodrigo; Newton, Michael I.; Brown, Carl V.; McHale, Glen

2016-01-01

Wetting and dewetting are both fundamental modes of motion of liquids on solid surfaces. They are critically important for processes in biology, chemistry, and engineering, such as drying, coating, and lubrication. However, recent progress in wetting, which has led to new fields such as superhydrophobicity and liquid marbles, has not been matched by dewetting. A significant problem has been the inability to study the model system of a uniform film dewetting from a nonwetting surface to a single macroscopic droplet—a barrier that does not exist for the reverse wetting process of a droplet spreading into a film. We report the dewetting of a dielectrophoresis-induced film into a single equilibrium droplet. The emergent picture of the full dewetting dynamics is of an initial regime, where a liquid rim recedes at constant speed and constant dynamic contact angle, followed by a relatively short exponential relaxation of a spherical cap shape. This sharply contrasts with the reverse wetting process, where a spreading droplet follows a smooth sequence of spherical cap shapes. Complementary numerical simulations and a hydrodynamic model reveal a local dewetting mechanism driven by the equilibrium contact angle, where contact line slip dominates the dewetting dynamics. Our conclusions can be used to understand a wide variety of processes involving liquid dewetting, such as drop rebound, condensation, and evaporation. In overcoming the barrier to studying single film-to-droplet dewetting, our results provide new approaches to fluid manipulation and uses of dewetting, such as inducing films of prescribed initial shapes and slip-controlled liquid retraction. PMID:27704042

Not spreading in reverse: The dewetting of a liquid film into a single drop.

PubMed

Edwards, Andrew M J; Ledesma-Aguilar, Rodrigo; Newton, Michael I; Brown, Carl V; McHale, Glen

2016-09-01

Wetting and dewetting are both fundamental modes of motion of liquids on solid surfaces. They are critically important for processes in biology, chemistry, and engineering, such as drying, coating, and lubrication. However, recent progress in wetting, which has led to new fields such as superhydrophobicity and liquid marbles, has not been matched by dewetting. A significant problem has been the inability to study the model system of a uniform film dewetting from a nonwetting surface to a single macroscopic droplet-a barrier that does not exist for the reverse wetting process of a droplet spreading into a film. We report the dewetting of a dielectrophoresis-induced film into a single equilibrium droplet. The emergent picture of the full dewetting dynamics is of an initial regime, where a liquid rim recedes at constant speed and constant dynamic contact angle, followed by a relatively short exponential relaxation of a spherical cap shape. This sharply contrasts with the reverse wetting process, where a spreading droplet follows a smooth sequence of spherical cap shapes. Complementary numerical simulations and a hydrodynamic model reveal a local dewetting mechanism driven by the equilibrium contact angle, where contact line slip dominates the dewetting dynamics. Our conclusions can be used to understand a wide variety of processes involving liquid dewetting, such as drop rebound, condensation, and evaporation. In overcoming the barrier to studying single film-to-droplet dewetting, our results provide new approaches to fluid manipulation and uses of dewetting, such as inducing films of prescribed initial shapes and slip-controlled liquid retraction.

Analysis of the phase transition in the two-dimensional Ising ferromagnet using a Lempel-Ziv string-parsing scheme and black-box data-compression utilities

NASA Astrophysics Data System (ADS)

Melchert, O.; Hartmann, A. K.

2015-02-01

In this work we consider information-theoretic observables to analyze short symbolic sequences, comprising time series that represent the orientation of a single spin in a two-dimensional (2D) Ising ferromagnet on a square lattice of size L2=1282 for different system temperatures T . The latter were chosen from an interval enclosing the critical point Tc of the model. At small temperatures the sequences are thus very regular; at high temperatures they are maximally random. In the vicinity of the critical point, nontrivial, long-range correlations appear. Here we implement estimators for the entropy rate, excess entropy (i.e., "complexity"), and multi-information. First, we implement a Lempel-Ziv string-parsing scheme, providing seemingly elaborate entropy rate and multi-information estimates and an approximate estimator for the excess entropy. Furthermore, we apply easy-to-use black-box data-compression utilities, providing approximate estimators only. For comparison and to yield results for benchmarking purposes, we implement the information-theoretic observables also based on the well-established M -block Shannon entropy, which is more tedious to apply compared to the first two "algorithmic" entropy estimation procedures. To test how well one can exploit the potential of such data-compression techniques, we aim at detecting the critical point of the 2D Ising ferromagnet. Among the above observables, the multi-information, which is known to exhibit an isolated peak at the critical point, is very easy to replicate by means of both efficient algorithmic entropy estimation procedures. Finally, we assess how good the various algorithmic entropy estimates compare to the more conventional block entropy estimates and illustrate a simple modification that yields enhanced results.

Sporadic on/off switching of HTLV-1 Tax expression is crucial to maintain the whole population of virus-induced leukemic cells.

PubMed

Mahgoub, Mohamed; Yasunaga, Jun-Ichirou; Iwami, Shingo; Nakaoka, Shinji; Koizumi, Yoshiki; Shimura, Kazuya; Matsuoka, Masao

2018-02-06

Viruses causing chronic infection artfully manipulate infected cells to enable viral persistence in vivo under the pressure of immunity. Human T-cell leukemia virus type 1 (HTLV-1) establishes persistent infection mainly in CD4+ T cells in vivo and induces leukemia in this subset. HTLV-1-encoded Tax is a critical transactivator of viral replication and a potent oncoprotein, but its significance in pathogenesis remains obscure due to its very low level of expression in vivo. Here, we show that Tax is expressed in a minor fraction of leukemic cells at any given time, and importantly, its expression spontaneously switches between on and off states. Live cell imaging revealed that the average duration of one episode of Tax expression is ∼19 hours. Knockdown of Tax rapidly induced apoptosis in most cells, indicating that Tax is critical for maintaining the population, even if its short-term expression is limited to a small subpopulation. Single-cell analysis and computational simulation suggest that transient Tax expression triggers antiapoptotic machinery, and this effect continues even after Tax expression is diminished; this activation of the antiapoptotic machinery is the critical event for maintaining the population. In addition, Tax is induced by various cytotoxic stresses and also promotes HTLV-1 replication. Thus, it seems that Tax protects infected cells from apoptosis and increases the chance of viral transmission at a critical moment. Keeping the expression of Tax minimal but inducible on demand is, therefore, a fundamental strategy of HTLV-1 to promote persistent infection and leukemogenesis. Copyright © 2018 the Author(s). Published by PNAS.

The functional neuroanatomy of multitasking: combining dual tasking with a short term memory task.

PubMed

Deprez, Sabine; Vandenbulcke, Mathieu; Peeters, Ron; Emsell, Louise; Amant, Frederic; Sunaert, Stefan

2013-09-01

Insight into the neural architecture of multitasking is crucial when investigating the pathophysiology of multitasking deficits in clinical populations. Presently, little is known about how the brain combines dual-tasking with a concurrent short-term memory task, despite the relevance of this mental operation in daily life and the frequency of complaints related to this process, in disease. In this study we aimed to examine how the brain responds when a memory task is added to dual-tasking. Thirty-three right-handed healthy volunteers (20 females, mean age 39.9 ± 5.8) were examined with functional brain imaging (fMRI). The paradigm consisted of two cross-modal single tasks (a visual and auditory temporal same-different task with short delay), a dual-task combining both single tasks simultaneously and a multi-task condition, combining the dual-task with an additional short-term memory task (temporal same-different visual task with long delay). Dual-tasking compared to both individual visual and auditory single tasks activated a predominantly right-sided fronto-parietal network and the cerebellum. When adding the additional short-term memory task, a larger and more bilateral frontoparietal network was recruited. We found enhanced activity during multitasking in components of the network that were already involved in dual-tasking, suggesting increased working memory demands, as well as recruitment of multitask-specific components including areas that are likely to be involved in online holding of visual stimuli in short-term memory such as occipito-temporal cortex. These results confirm concurrent neural processing of a visual short-term memory task during dual-tasking and provide evidence for an effective fMRI multitasking paradigm. © 2013 Elsevier Ltd. All rights reserved.

The Distinctiveness of the Word-Length Effect

ERIC Educational Resources Information Center

Hulme, Charles; Neath, Ian; Stuart, George; Shostak, Lisa; Surprenant, Aimee M.; Brown, Gordon D. A.

2006-01-01

The authors report 2 experiments that compare the serial recall of pure lists of long words, pure lists of short words, and lists of long or short words containing just a single isolated word of a different length. In both experiments for pure lists, there was a substantial recall advantage for short words; the isolated words were recalled better…

Visual short-term memory for high resolution associations is impaired in patients with medial temporal lobe damage.

PubMed

Koen, Joshua D; Borders, Alyssa A; Petzold, Michael T; Yonelinas, Andrew P

2017-02-01

The medial temporal lobe (MTL) plays a critical role in episodic long-term memory, but whether the MTL is necessary for visual short-term memory is controversial. Some studies have indicated that MTL damage disrupts visual short-term memory performance whereas other studies have failed to find such evidence. To account for these mixed results, it has been proposed that the hippocampus is critical in supporting short-term memory for high resolution complex bindings, while the cortex is sufficient to support simple, low resolution bindings. This hypothesis was tested in the current study by assessing visual short-term memory in patients with damage to the MTL and controls for high resolution and low resolution object-location and object-color associations. In the location tests, participants encoded sets of two or four objects in different locations on the screen. After each set, participants performed a two-alternative forced-choice task in which they were required to discriminate the object in the target location from the object in a high or low resolution lure location (i.e., the object locations were very close or far away from the target location, respectively). Similarly, in the color tests, participants were presented with sets of two or four objects in a different color and, after each set, were required to discriminate the object in the target color from the object in a high or low resolution lure color (i.e., the lure color was very similar or very different, respectively, to the studied color). The patients were significantly impaired in visual short-term memory, but importantly, they were more impaired for high resolution object-location and object-color bindings. The results are consistent with the proposal that the hippocampus plays a critical role in forming and maintaining complex, high resolution bindings. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Quenching star formation with quasar outflows launched by trapped IR radiation

NASA Astrophysics Data System (ADS)

Costa, Tiago; Rosdahl, Joakim; Sijacki, Debora; Haehnelt, Martin G.

2018-06-01

We present cosmological radiation-hydrodynamic simulations, performed with the code RAMSES-RT, of radiatively-driven outflows in a massive quasar host halo at z = 6. Our simulations include both single- and multi-scattered radiation pressure on dust from a quasar and are compared against simulations performed with thermal feedback. For radiation pressure-driving, we show that there is a critical quasar luminosity above which a galactic outflow is launched, set by the equilibrium of gravitational and radiation forces. While this critical luminosity is unrealistically high in the single-scattering limit for plausible black hole masses, it is in line with a ≈ 3 × 10^9 M_⊙ black hole accreting at its Eddington limit, if infrared (IR) multi-scattering radiation pressure is included. The outflows are fast (v ≳ 1000 km s^{-1}) and strongly mass-loaded with peak mass outflow rates ≈ 10^3 - 10^4 M_⊙ yr^{-1}, but short-lived (< 10 Myr). Outflowing material is multi-phase, though predominantly composed of cool gas, forming via a thermal instability in the shocked swept-up component. Radiation pressure- and thermally-driven outflows both affect their host galaxies significantly, but in different, complementary ways. Thermally-driven outflows couple more efficiently to diffuse halo gas, generating more powerful, hotter and more volume-filling outflows. IR radiation, through its ability to penetrate dense gas via diffusion, is more efficient at ejecting gas from the bulge. The combination of gas ejection through outflows with internal pressurisation by trapped IR radiation leads to a complete shut down of star formation in the bulge. We hence argue that radiation pressure-driven feedback may be an important ingredient in regulating star formation in compact starbursts, especially during the quasar's `obscured' phase.

Glycyrrhizin Treatment Facilitates Extinction of Conditioned Fear Responses After a Single Prolonged Stress Exposure in Rats.

PubMed

Lai, Shuhua; Wu, Gangwei; Jiang, Zhixian

2018-01-01

Impaired fear memory extinction is widely considered a key mechanism of post-traumatic stress disorder (PTSD). Recent studies have suggested that neuroinflammation after a single prolonged stress (SPS) exposure may play a critical role in the impaired fear memory extinction. Studies have shown that high mobility group box chromosomal protein 1 (HMGB-1) is critically involved in neuroinflammation. However, the role of HMGB-1 underlying the development of impairment of fear memory extinction is still not known. Thus, we examined the levels of HMGB-1 in the basolateral amygdala (BLA) following SPS using Western blot and evaluated the levels of microglia and astrocytes activation in the BLA after SPS using immunohistochemical staining. We then examined the effects of pre-SPS intra-BLA administration of glycyrrhizin, an HMGB1 inhibitor, or LPS-RS, a competitive TLR4 antagonist, on subsequent post-SPS fear extinction. We found that SPS treatment prolonged the extinction of contextual fear memory after the SPS. The impairment of SPS-induced extinction of contextual fear memory was associated with increased HMGB1 and Toll-like receptor 4 (TLR4) levels in the BLA. Additionally, the impairment of SPS-induced extinction of contextual fear memory was associated with increased activation of microglia and astrocyte in the BLA. Intra-BLA administrations of glycyrrhizin (HMGB-1 inhibitor) or LPS-RS (TLR4 antagonist) can prevent the development of SPS-induced fear extinction impairment. Taken together, these results suggested that SPS treatment may not only produce short term effects on the HMGB1/TLR4-mediated pro-inflammation, but alter the response of microglia and astrocytes to the exposure to fear associated contextual stimuli. © 2018 The Author(s). Published by S. Karger AG, Basel.

Correlations between critical current density, j{sub c}, critical temperature, T{sub c}, and structural quality of Y{sub 1}B{sub 2}Cu{sub 3}O{sub 7-x} thin superconducting films

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

Chrzanowski, J.; Xing, W.B.; Atlan, D.

1994-12-31

Correlations between critical current density (j{sub c}) critical temperature (T{sub c}) and the density of edge dislocations and nonuniform strain have been observed in YBCO thin films deposited by pulsed laser ablation on (001) LaAlO{sub 3} single crystals. Distinct maxima in j{sub c} as a function of the linewidths of the (00{ell}) Bragg reflections and as a function of the mosaic spread have been found in the epitaxial films. These maxima in j{sub c} indicate that the magnetic flux lines, in films of structural quality approaching that of single crystals, are insufficiently pinned which results in a decreased critical currentmore » density. T{sub c} increased monotonically with improving crystalline quality and approached a value characteristic of a pure single crystal. A strong correlation between j{sub c} and the density of edge dislocations N{sub D} was found. At the maximum of the critical current density the density of edge dislocations was estimated to be N{sub D}{approximately}1-2 x 10{sup 9}/cm{sup 2}.« less

Correlations between critical current density, j(sub c), critical temperature, T(sub c),and structural quality of Y1B2Cu3O(7-x) thin superconducting films

NASA Technical Reports Server (NTRS)

Chrzanowski, J.; Xing, W. B.; Atlan, D.; Irwin, J. C.; Heinrich, B.; Cragg, R. A.; Zhou, H.; Angus, V.; Habib, F.; Fife, A. A.

1995-01-01

Correlations between critical current density (j(sub c)) critical temperature (T(sub c)) and the density of edge dislocations and nonuniform strain have been observed in YBCO thin films deposited by pulsed laser ablation on (001) LaAlO3 single crystals. Distinct maxima in j(sub c) as a function of the linewidths of the (00 l) Bragg reflections and as a function of the mosaic spread have been found in the epitaxial films. These maxima in j(sub c) indicate that the magnetic flux lines, in films of structural quality approachingthat of single crystals, are insufficiently pinned which results in a decreased critical current density. T(sub c) increased monotonically with improving crystalline quality and approached a value characteristic of a pure single crystal. A strong correlation between j(sub c) and the density of edge dislocations ND was found. At the maximum of the critical current density the density of edge dislocations was estimated to be N(sub D) approximately 1-2 x 10(exp 9)/sq cm.

Variation in the local population dynamics of the short-lived Opuntia macrorhiza (Cactaceae).

PubMed

Haridas, C V; Keeler, Kathleen H; Tenhumberg, Brigitte

2015-03-01

Spatiotemporal variation in demographic rates can have profound effects for population persistence, especially for dispersal-limited species living in fragmented landscapes. Long-term studies of plants in such habitats help with understanding the impacts of fragmentation on population persistence but such studies are rare. In this work, we reanalyzed demographic data from seven years of the short-lived cactus Opuntia macrorhiza var. macrorhiza at five plots in Boulder, Colorado. Previous work combining data from all years and all plots predicted a stable population (deterministic log lamda approximately 0). This approach assumed that all five plots were part of a single population. Since the plots were located in a suburban-agricultural interface separated by highways, grazing lands, and other barriers, and O. macrorhiza is likely dispersal limited, we analyzed the dynamics of each plot separately using stochastic matrix models assuming each plot represented a separate population. We found that the stochastic population growth rate log lamdaS varied widely between populations (log lamdaS = 0.1497, 0.0774, -0.0230, -0.2576, -0.4989). The three populations with the highest growth rates were located close together in space, while the two most isolated populations had the lowest growth rates suggesting that dispersal between populations is critical for the population viability of O. macrorhiza. With one exception, both our prospective (stochastic elasticity) and retrospective (stochastic life table response experiments) analysis suggested that means of stasis and growth, especially of smaller plants, were most important for population growth rate. This is surprising because recruitment is typically the most important vital rate in a short-lived species such as O. macrorhiza. We found that elasticity to the variance was mostly negligible, suggesting that O. macrorhiza populations are buffered against large temporal variation. Finally, single-year elasticities to means of transitions to the smallest stage (mostly due to reproduction) and growth differed considerably from their long-term elasticities. It is important to be aware of this difference when using models to predict the effect of manipulating plant vital rates within the time frame of typical plant demographic studies.

Floral resource availability from groundcover promotes bee abundance in coffee agroecosystems.

PubMed

Fisher, Kaleigh; Gonthier, David J; Ennis, Katherine K; Perfecto, Ivette

2017-09-01

Patterns of bee abundance and diversity across different spatial scales have received thorough research consideration. However, the impact of short- and long-term temporal resource availability on biodiversity has been less explored. This is highly relevant in tropical agricultural systems for pollinators, as many foraging periods of pollinators extend beyond flowering of any single crop species. In this study, we sought to understand how bee communities in tropical agroecosystems changed between seasons, and if short- and long-term floral resource availability influenced their diversity and abundance. We used a threshold analysis approach in order to explore this relationship at two time scales. This study took place in a region dominated by coffee agroecosystems in Southern Mexico. This was an ideal system because the landscape offers a range of coffee management regimes that maintain heterogeneity in floral resource availability spatially and temporally. We found that the bee community varies significantly between seasons. There were higher abundances of native social, solitary and managed honey bees during the dry season when coffee flowers. Additionally, we found that floral resources from groundcover, but not trees, were associated with bee abundance. Further, the temporal scale of the availability of these resources is important, whereby short-term floral resource availability appears particularly important in maintaining high bee abundance at sites with lower seasonal complementarity. We argue that in addition to spatial resource heterogeneity, temporal resource heterogeneity is critical in explaining bee community patterns, and should thus be considered to promote pollinator conservation. © 2017 by the Ecological Society of America.

Quantitative analysis of single-molecule superresolution images

PubMed Central

Coltharp, Carla; Yang, Xinxing; Xiao, Jie

2014-01-01

This review highlights the quantitative capabilities of single-molecule localization-based superresolution imaging methods. In addition to revealing fine structural details, the molecule coordinate lists generated by these methods provide the critical ability to quantify the number, clustering, and colocalization of molecules with 10 – 50 nm resolution. Here we describe typical workflows and precautions for quantitative analysis of single-molecule superresolution images. These guidelines include potential pitfalls and essential control experiments, allowing critical assessment and interpretation of superresolution images. PMID:25179006

Diamond turning of Si and Ge single crystals

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

Blake, P.; Scattergood, R.O.

Single-point diamond turning studies have been completed on Si and Ge crystals. A new process model was developed for diamond turning which is based on a critical depth of cut for plastic flow-to-brittle fracture transitions. This concept, when combined with the actual machining geometry for single-point turning, predicts that {open_quotes}ductile{close_quotes} machining is a combined action of plasticity and fracture. Interrupted cutting experiments also provide a meant to directly measure the critical depth parameter for given machining conditions.

Activity inhibition on municipal activated sludge by single-walled carbon nanotubes

NASA Astrophysics Data System (ADS)

Parise, Alex; Thakor, Harshrajsinh; Zhang, Xiaoqi

2014-01-01

The objective of this study was to evaluate the respiratory activity inhibition of activated sludge used in a typical wastewater treatment plant by single-walled carbon nanotubes (SWCNTs) with different length and functionality. Four types of SWCNTs were evaluated: short, functionalized short, long, and functionalized long. Based on the effective concentration (EC50) values obtained, we determined that functionalized SWCNTs resulted in a higher microbial respiratory inhibition than non-functionalized nanotubes, and long SWCNTs gave a higher microbial respiratory inhibition than their short counterparts. Among the four types of SWCNTs studied, functionalized long exhibited the highest respiration inhibition. Scanning electron microscopy imaging indicates that the long SWCNTs dispersed more favorably after sonication than the short variety. The findings demonstrated that the toxicity of CNTs (exhibited by respiratory inhibition) is related to their physical properties; the length and functionality of SWCNTs affected the toxicity of SWCNTs in a mixed-cultured biologic system.

Short- and long-term psychosocial of a single episode of alcoholic intoxication: a cohort study among Dutch adolescents.

PubMed

de Boo, Gerly M; Thijssen, Maartje A; Lasham, Carole; Plötz, Frans B

2016-07-01

The short- and long-term psychological consequences of a single episode of alcohol intoxication in adolescents are unknown. Twenty-four adolescents (12 M, 12 F), mean age 18.3 ± 1.1 years, who had been admitted to the pediatric ward with alcohol intoxication (mean age at admission 15.6 ± 1.1) and thirty-two parents were interviewed on the intoxication episode and the subsequent consequences. This interview took place 2-3 years after the alcohol intoxication. At the same time, all participants completed questionnaires, assessing general and demographic information, detailed information about current alcohol use, present-day health-related quality of life, and psychological well-being. We observed that short-term (<6 months) psychosocial consequences on family life, family rules, friendships, and school were retrospectively judged more neutral and even more positive than negative by adolescents and their parents. Eighty-six percent of all reported changes by adolescents and parents, directly after the intoxication, lasted 6 months or less. At follow-up present-day quality of life was comparable to the norm, social functioning was significantly better and their mental health proved to be within the normal range (no emotional and behavioral problems). Since the intoxication, none of the participants had dropped out of school and their present-day alcohol use was comparable to estimated averages for their age. Short- and long-term psychosocial consequences of a single episode of alcohol intoxication were positively judged by adolescents and their parents. • Alcohol abuse among adolescents is a growing concern both in society and pediatrics. What is new: • This manuscript describes short and long term psychological consequences of a single episode of alcohol intoxication in adolescents.

Free energy and phase equilibria for the restricted primitive model of ionic fluids from Monte Carlo simulations

NASA Astrophysics Data System (ADS)

Orkoulas, Gerassimos; Panagiotopoulos, Athanassios Z.

1994-07-01

In this work, we investigate the liquid-vapor phase transition of the restricted primitive model of ionic fluids. We show that at the low temperatures where the phase transition occurs, the system cannot be studied by conventional molecular simulation methods because convergence to equilibrium is slow. To accelerate convergence, we propose cluster Monte Carlo moves capable of moving more than one particle at a time. We then address the issue of charged particle transfers in grand canonical and Gibbs ensemble Monte Carlo simulations, for which we propose a biased particle insertion/destruction scheme capable of sampling short interparticle distances. We compute the chemical potential for the restricted primitive model as a function of temperature and density from grand canonical Monte Carlo simulations and the phase envelope from Gibbs Monte Carlo simulations. Our calculated phase coexistence curve is in agreement with recent results of Caillol obtained on the four-dimensional hypersphere and our own earlier Gibbs ensemble simulations with single-ion transfers, with the exception of the critical temperature, which is lower in the current calculations. Our best estimates for the critical parameters are T*c=0.053, ρ*c=0.025. We conclude with possible future applications of the biased techniques developed here for phase equilibrium calculations for ionic fluids.

Domain wall motion in ferroelectrics: Barkhausen noise

NASA Astrophysics Data System (ADS)

Shur, V.; Rumyantsev, E.; Kozhevnikov, V.; Nikolaeva, E.; Shishkin, E.

2002-03-01

The switching current noise has been recorded during polarization reversal in single-crystalline gadolinium molybdate (GMO) and lithium tantalate (LT). Analysis of Barkhausen noise (BN) data allows to classify the noise types by determination of the critical indexes and fractal dimensions. BN is manifested as the short pulses during the polarization reversal. We have analyzed the BN data recorded in GMO and LT with various types of controlled domain structure. The data treatment in terms of probability distribution of duration, area and energy of individual pulses reveals the critical behavior typical for the fractal records in time. We used the Fourier transform and Hurst's rescaled range analysis for obtaining the Hurst factor, fractal dimension and classifying the noise types. We investigated by computer simulation the mechanism of sideways motion of 180O domain wall by nucleation at the wall taking into account the nuclei-nuclei interaction. It was shown that the moving domain walls display the fractal shape and their motion is accompanied by Flicker noise, which is in accord with experimental data. The research was made possible in part by Programs "Basic Research in Russian Universities" and "Priority Research in High School. Electronics", by Grant No. 01-02-17443 of RFBR, by Award No.REC-005 of CRDF.

Critical behavior of a two-step contagion model with multiple seeds

NASA Astrophysics Data System (ADS)

Choi, Wonjun; Lee, Deokjae; Kahng, B.

2017-06-01

A two-step contagion model with a single seed serves as a cornerstone for understanding the critical behaviors and underlying mechanism of discontinuous percolation transitions induced by cascade dynamics. When the contagion spreads from a single seed, a cluster of infected and recovered nodes grows without any cluster merging process. However, when the contagion starts from multiple seeds of O (N ) where N is the system size, a node weakened by a seed can be infected more easily when it is in contact with another node infected by a different pathogen seed. This contagion process can be viewed as a cluster merging process in a percolation model. Here we show analytically and numerically that when the density of infectious seeds is relatively small but O (1 ) , the epidemic transition is hybrid, exhibiting both continuous and discontinuous behavior, whereas when it is sufficiently large and reaches a critical point, the transition becomes continuous. We determine the full set of critical exponents describing the hybrid and the continuous transitions. Their critical behaviors differ from those in the single-seed case.

Replacement Planning: A Starting Point for Succession Planning and Talent Management

ERIC Educational Resources Information Center

Rothwell, William J.

2011-01-01

Replacement planning is a process of identifying short-term or long-term backups so that organizations have people who can assume responsibility for critical positions during emergencies. Individuals identified as "replacements" are not promised promotions; rather, they are prepared to the point where they can assume a critical position long…

A Critical Discourse Analysis of "No Promo Homo" Policies in US Schools

ERIC Educational Resources Information Center

Barrett, Brian; Bound, Arron M.

2015-01-01

This article presents a critical discourse analysis of "no promo homo" policies and their effects in US schools. "No promo homo"--short for "no promotion of homosexuality" (Eskridge, 2000, p. 1329)--polices have been adopted across nine states and several local school districts in the United States. They direct…

Critical Review: Medical Students' Motivation after Failure

ERIC Educational Resources Information Center

Holland, Chris

2016-01-01

About 10% of students in each years' entrants to medical school will encounter academic failure at some stage in their programme. The usual approach to supporting these students is to offer them short term remedial study programmes that often enhance approaches to study that are orientated towards avoiding failure. In this critical review I will…

Cigarette smoke condensate induces differential expression and promoter methylation profiles of critical genes involved in lung cancer in NL-20 lung cells in vitro: short-term and chronic exposure.

PubMed

Word, Beverly; Lyn-Cook, Lascelles E; Mwamba, Bibi; Wang, Honggang; Lyn-Cook, Beverly; Hammons, George

2013-01-01

Establishing early diagnostic markers of harm is critical for effective prevention programs and regulation of tobacco products. This study examined effects of cigarette smoke condensate (CSC) on expression and promoter methylation profile of critical genes (DAPK, ECAD, MGMT, and RASSF1A) involved in lung cancer development in different human lung cell lines. NL-20 cells were treated with 0.1-100 μg/ml of CSC for 24 to 72 hrs for short-term exposures. DAPK expression or methylation status was not significantly affected. However, CSC treatment resulted in changes in expression and promoter methylation profile of ECAD, MGMT, and RASSF1A. For chronic studies, cells were exposed to 1 or 10 μg/ml CSC up to 28 days. Cells showed morphological changes associated with transformation and changes in invasion capacities and global methylation status. This study provides critical data suggesting that epigenetic changes could serve as an early biomarker of harm due to exposure to cigarette smoke.

Encoding: The Keystone to Efficient Functioning of Verbal Short-Term Memory

ERIC Educational Resources Information Center

Barry, Johanna G.; Sabisch, Beate; Friederici, Angela D.; Brauer, Jens

2011-01-01

Verbal short-term memory (VSTM) is thought to play a critical role in language learning. It is indexed by the nonword repetition task where listeners are asked to repeat meaningless words like "blonterstaping". The present study investigated the effect on nonword repetition performance of differences in efficiency of functioning of some part of…

Grouping in Short-Term Memory: Do Oscillators Code the Positions of Items?

ERIC Educational Resources Information Center

Ng, Honey L. H.; Maybery, Murray T.

2005-01-01

According to several current models of short-term memory, items are retained in order by associating them with positional codes. The models differ as to whether temporal oscillators provide those codes. The authors examined errors in recall of sequences comprising 2 groups of 4 consonants. A critical manipulation was the precise timing of items…

Meta-Travel: A Critical Inquiry into a China Study Tour

ERIC Educational Resources Information Center

Riggan, Jennifer; Gwak, Sonya; Lesnick, Joy; Jackson, Kara; Olitsky, Stacey

2011-01-01

Short-term study tours are among the fastest growing of study abroad experiences and serve the largest percentage of students choosing to study abroad. Fifty-six percent of students studying abroad go on short-term study trips lasting anywhere from two to eight weeks. These trips have the advantage of being able to provide study travel experiences…

On the Myth of the Crisis of Representation: A Response to Gilbourne, Jones and Jordan

ERIC Educational Resources Information Center

Gard, Michael

2014-01-01

The author observes that, in "Applied Utility and the Auto-Ethnographic Short Story: Persuasions for, and Illustrations of, Writing Critical Social Science," Gilbourne, Jones and Jordan present claims about why we might choose to represent auto-ethnographic data in a literary form such as short story and for the "potential" or…

A Multiple Case Study of Verbal Short-Term Memory in Velo-Cardio-Facial Syndrome

ERIC Educational Resources Information Center

Majerus, S.; Glaser, B.; Van der Linden, M.; Eliez, S.

2006-01-01

Background: Velo-cardio-facial syndrome (VCFS, 22q 11.2 deletion) is characterized by severely delayed language development. The current study explored the integrity of verbal short-term memory (STM), a cognitive function critically involved in language development, in eight children with VCFS. Methods: Using a multiple case study design, we…

Explaining Semantic Short-Term Memory Deficits: Evidence for the Critical Role of Semantic Control

ERIC Educational Resources Information Center

Hoffman, Paul; Jefferies, Elizabeth; Lambon Ralph, Matthew A.

2011-01-01

Patients with apparently selective short-term memory (STM) deficits for semantic information have played an important role in developing multi-store theories of STM and challenge the idea that verbal STM is supported by maintaining activation in the language system. We propose that semantic STM deficits are not as selective as previously thought…

Growth Mechanism Studies of ZnO Nanowires: Experimental Observations and Short-Circuit Diffusion Analysis.

PubMed

Shih, Po-Hsun; Wu, Sheng Yun

2017-07-21

Plenty of studies have been performed to probe the diverse properties of ZnO nanowires, but only a few have focused on the physical properties of a single nanowire since analyzing the growth mechanism along a single nanowire is difficult. In this study, a single ZnO nanowire was synthesized using a Ti-assisted chemical vapor deposition (CVD) method to avoid the appearance of catalytic contamination. Two-dimensional energy dispersive spectroscopy (EDS) mapping with a diffusion model was used to obtain the diffusion length and the activation energy ratio. The ratio value is close to 0.3, revealing that the growth of ZnO nanowires was attributed to the short-circuit diffusion.

Fluorescence Quenching by TEMPO: A Sub-30 Å Single-Molecule Ruler

PubMed Central

Zhu, Peizhi; Clamme, Jean-Pierre; Deniz, Ashok A.

2005-01-01

A series of DNA molecules labeled with 5-carboxytetramethylrhodamine (5-TAMRA) and the small nitroxide radical TEMPO were synthesized and tested to investigate whether the intramolecular quenching efficiency can be used to measure short intramolecular distances in small ensemble and single-molecule experiments. In combination with distance calculations using molecular mechanics modeling, the experimental results from steady-state ensemble fluorescence and fluorescence correlation spectroscopy measurements both show an exponential decrease in the quenching rate constant with the dye-quencher distance in the 10–30 Å range. The results demonstrate that TEMPO-5-TAMRA fluorescence quenching is a promising method to measure short distance changes within single biomolecules. PMID:16199509

Unimolecular Logic Gate with Classical Input by Single Gold Atoms.

PubMed

Skidin, Dmitry; Faizy, Omid; Krüger, Justus; Eisenhut, Frank; Jancarik, Andrej; Nguyen, Khanh-Hung; Cuniberti, Gianaurelio; Gourdon, Andre; Moresco, Francesca; Joachim, Christian

2018-02-27

By a combination of solution and on-surface chemistry, we synthesized an asymmetric starphene molecule with two long anthracenyl input branches and a short naphthyl output branch on the Au(111) surface. Starting from this molecule, we could demonstrate the working principle of a single molecule NAND logic gate by selectively contacting single gold atoms by atomic manipulation to the longer branches of the molecule. The logical input "1" ("0") is defined by the interaction (noninteraction) of a gold atom with one of the input branches. The output is measured by scanning tunneling spectroscopy following the shift in energy of the electronic tunneling resonances at the end of the short branch of the molecule.

Epitaxial Ge2Sb2Te5 probed by single cycle THz pulses of coherent synchrotron radiation

NASA Astrophysics Data System (ADS)

Bragaglia, V.; Schnegg, A.; Calarco, R.; Holldack, K.

2016-10-01

A THz-probe spectroscopy scheme with laser-induced single cycle pulses of coherent synchrotron radiation is devised and adapted to reveal the dynamic THz transmittance response in epitaxially grown phase change materials upon 800 nm fs-laser excitation. Amorphous (a-) and crystalline (c-) films of the prototypical Ge2Sb2Te5 (GST) alloy are probed with single cycle THz pulses tuned to the spectral range of the highest absorption contrast at 2 THz. After an initial instantaneous sub-picosecond (ps) dynamic THz transmittance drop, the response of a-GST in that range is dominated only by a short recovery time τshort = 2 ps of the excited carriers. On the contrary, the behavior of the c-GST response displays a short decay of 0.85 ps followed by a long one τlong = 90 ps, suggesting that vacancy layers in an ordered c-GST play a role as dissipation channel for photo-induced free carriers.

Design and fabrication of single-crystal GaN nano-bridge on homogeneous substrate for nanoindentation

NASA Astrophysics Data System (ADS)

Hung, Shang-Chao

2014-12-01

This study reports a simple method to design and fabricate a freestanding GaN nano-bridge over a homogeneous short column as supporting leg. Test samples were fabricated from MOCVD-grown single-crystal GaN films over sapphire substrate using a FIB milling to leave freestanding short spans. We also investigated the nanoindentation characteristics and the corresponding nanoscopic mechanism of the GaN nano-bridge and its short column with a conical indenter inside transmission electron microscopy. The stress-strain mechanical properties and Young's modulus have also been examined and calculated as 108 GPa ± 4.8 % by the strain energy method. The significant slope switch of the L- D curve corresponds to the transition from the single-point bending indentation to the surface stretching indentation and has been interpreted with the evolution of TEM images. This freestanding fabrication and test have key advantages to characterize nanoscale behavior of one-dimensional bridge structure and greater ease of sample preparation over other micro-fabrication techniques.

Short-Term EEG Spectral Pattern as a Single Event in EEG Phenomenology

PubMed Central

Fingelkurts, Al. A; Fingelkurts, An. A

2010-01-01

Spectral decomposition, to this day, still remains the main analytical paradigm for the analysis of EEG oscillations. However, conventional spectral analysis assesses the mean characteristics of the EEG power spectra averaged out over extended periods of time and/or broad frequency bands, thus resulting in a “static” picture which cannot reflect adequately the underlying neurodynamic. A relatively new promising area in the study of EEG is based on reducing the signal to elementary short-term spectra of various types in accordance with the number of types of EEG stationary segments instead of using averaged power spectrum for the whole EEG. It is suggested that the various perceptual and cognitive operations associated with a mental or behavioural condition constitute a single distinguishable neurophysiological state with a distinct and reliable spectral pattern. In this case, one type of short-term spectral pattern may be considered as a single event in EEG phenomenology. To support this assumption the following issues are considered in detail: (a) the relations between local EEG short-term spectral pattern of particular type and the actual state of the neurons in underlying network and a volume conduction; (b) relationship between morphology of EEG short-term spectral pattern and the state of the underlying neurodynamical system i.e. neuronal assembly; (c) relation of different spectral pattern components to a distinct physiological mechanism; (d) relation of different spectral pattern components to different functional significance; (e) developmental changes of spectral pattern components; (f) heredity of the variance in the individual spectral pattern and its components; (g) intra-individual stability of the sets of EEG short-term spectral patterns and their percent ratio; (h) discrete dynamics of EEG short-term spectral patterns. Functional relevance (consistency) of EEG short-term spectral patterns in accordance with the changes of brain functional state, cognitive task and with different neuropsychopathologies is demonstrated. PMID:21379390

The use of short and long PCR products for improved detection of prunus necrotic ringspot virus in woody plants.

PubMed

Rosner, A; Maslenin, L; Spiegel, S

1997-09-01

The reverse transcriptase-polymerase chain reaction (RT-PCR) was used for detection of prunus necrotic ringspot virus (PNRSV) in dormant peach and almond trees by the application of two different pairs of primers yielding a short and a long product, respectively. The relative amount of the short (200 base pair, bp) product was higher than the longer (785 bp) product. PNRSV was detected better in plant tissues with a low virus concentration (e.g. dormant trees) by amplification of the short PCR product, whereas the long product was product was produced at higher virus titers. Simultaneous amplification of both short and long products was demonstrated using a three-primer mixture in a single reaction tube. In this assay, amplification of either PCR product indicated the presence of PNRSV-specific sequences in the plant tissue examined, thus covering a wide range of virus concentrations in a single test. Dilution of the RNA extracted from infected plant material resulted in a steep decline in the amplification of both short and long PCR products. In contrast, serial dilutions of the intermediate cDNA template differentially affected the amplification patterns: the relative amount of the short product increased whereas that of the long product decreased. These results may explain the preferential amplification of the short PCR product observed in samples containing low virus concentrations.

A Capped Dipeptide Which Simultaneously Exhibits Gelation and Crystallization Behavior.

PubMed

Martin, Adam D; Wojciechowski, Jonathan P; Bhadbhade, Mohan M; Thordarson, Pall

2016-03-08

Short peptides capped at their N-terminus are often highly efficient gelators, yet notoriously difficult to crystallize. This is due to strong unidirectional interactions within fibers, resulting in structure propagation only along one direction. Here, we synthesize the N-capped dipeptide, benzimidazole-diphenylalanine, which forms both hydrogels and single crystals. Even more remarkably, we show using atomic force microscopy the coexistence of these two distinct phases. We then use powder X-ray diffraction to investigate whether the single crystal structure can be extrapolated to the molecular arrangement within the hydrogel. The results suggest parallel β-sheet arrangement as the dominant structural motif, challenging existing models for gelation of short peptides, and providing new directions for the future rational design of short peptide gelators.

Distinguishing Raman from strongly coupled Brillouin amplification for short pulses

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

Jia, Qing; Barth, Ido; Edwards, Matthew R.

2016-05-15

Plasma-based amplification by strongly coupled Brillouin scattering has recently been suggested for the compression of a short seed laser to ultrahigh intensities in sub-quarter-critical-density plasmas. However, by employing detailed spectral analysis of particle-in-cell simulations in the same parameter regime, we demonstrate that, in fact, Raman backscattering amplification is responsible for the growth and compression of the high-intensity, leading spike, where most of the energy compression occurs, while the ion mode only affects the low-intensity tail of the amplified pulse. The critical role of the initial seed shape is identified. A number of subtleties in the numerical simulations are also pointedmore » out.« less

A short review on thermosonic flip chip bonding

NASA Astrophysics Data System (ADS)

Suppiah, Sarveshvaran; Ong, Nestor Rubio; Sauli, Zaliman; Sarukunaselan, Karunavani; Alcain, Jesselyn Barro; Shahimin, Mukhzeer Mohamad; Retnasamy, Vithyacharan

2017-09-01

This review is to study the evolution and key findings, critical technical challenges, solutions and bonding equipment of thermosonic flip chip bonding. Based on the review done, it was found that ultrasonic power, bonding time and force are the three main critical parameters need to be optimized in order to achieve sound and reliable bonding between the die and substrate. A close monitoring of the ultrasonic power helped to prevent over bonding phenomena on flexible substrate. Gold stud bumping is commonly used in thermosonic bonding compared to solder due to its better reliability obtained in the LED and optoelectronic packages. The review comprised short details on the available thermosonic bonding equipment in the semiconductor industry as well.

New Comment on Gibbs Density Surface of Fluid Argon: Revised Critical Parameters, L. V. Woodcock, Int. J. Thermophys. (2014) 35, 1770-1784

NASA Astrophysics Data System (ADS)

Umirzakov, I. H.

2018-01-01

The author comments on an article by Woodcock (Int J Thermophys 35:1770-1784, 2014), who investigates the idea of a critical line instead of a single critical point using the example of argon. In the introduction, Woodcock states that "The Van der Waals critical point does not comply with the Gibbs phase rule. Its existence is based upon a hypothesis rather than a thermodynamic definition". The present comment is a response to the statement by Woodcock. The comment mathematically demonstrates that a critical point is not only based on a hypothesis that is used to define values of two parameters of the Van der Waals equation of state. Instead, the author argues that a critical point is a direct consequence of the thermodynamic phase equilibrium conditions resulting in a single critical point. It is shown that the thermodynamic conditions result in the first and second partial derivatives of pressure with respect to volume at constant temperature at a critical point equal to zero which are usual conditions of an existence of a critical point.

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

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

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

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

Stimulated Brillouin scattering reduction induced by self-focusing for a single laser speckle interacting with an expanding plasma

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

Masson-Laborde, P. E.; Depierreux, S.; Loiseau, P.

2014-03-15

The origin of the low level of stimulated Brillouin scattering (SBS) observed in laser-plasma experiments carried out with a single laser speckle is investigated by means of three-dimensional simulations and modeling in the limit when the laser beam power P is well above the critical power for ponderomotive self-focusing We find that the order of magnitude of the time averaged reflectivities, together with the temporal and spatial SBS localization observed in our simulations, are correctly reproduced by our modeling. It is observed that, after a short transient stage, SBS reaches a significant level only (i) as long as the incidentmore » laser pulse is increasing in amplitude and (ii) in a single self-focused speckle located in the low-density front part of the plasma. In order to describe self-focusing in an inhomogeneous expanding plasma, we have derived a new Lagrangian density describing this process. Using then a variational approach, our model reproduces the position and the peak intensity of the self-focusing hot spot in the front part of the plasma density profile as well as the local density depletion in this hot spot. The knowledge of these parameters then makes it possible to estimate the spatial amplification of SBS as a function of the laser beam power and consequently to explain the experimentally observed SBS reflectivity, considerably reduced with respect to standard theory in the regime of large laser beam power.« less

Critical behavior of the van der Waals bonded ferromagnet Fe3 -xGeTe2

NASA Astrophysics Data System (ADS)

Liu, Yu; Ivanovski, V. N.; Petrovic, C.

2017-10-01

The critical properties of the single-crystalline van der Waals bonded ferromagnet Fe3 -xGeTe2 were investigated by bulk dc magnetization around the paramagnetic to ferromagnetic (FM) phase transition. The Fe3 -xGeTe2 single crystals grown by self-flux method with Fe deficiency x ≈0.36 exhibit bulk FM ordering below Tc=152 K. The Mössbauer spectroscopy was used to provide information on defects and local atomic environment in such crystals. Critical exponents β =0.372 (4 ) with a critical temperature Tc=151.25 (5 ) K and γ =1.265 (15 ) with Tc=151.17 (12 ) K are obtained by the Kouvel-Fisher method, whereas δ =4.50 (1 ) is obtained by a critical isotherm analysis at Tc=151 K. These critical exponents obey the Widom scaling relation δ =1 +γ /β , indicating self-consistency of the obtained values. With these critical exponents the isotherm M (H ) curves below and above the critical temperatures collapse into two independent universal branches, obeying the single scaling equation m =f±(h ) , where m and h are renormalized magnetization and field, respectively. The exponents determined in this study are close to those calculated from the results of the renormalization group approach for a heuristic model of three-dimensional Heisenberg (d =3 ,n =3 ) spins coupled with the attractive long-range interactions between spins that decay as J (r ) ≈r-(3 +σ ) with σ =1.89 .

Short Implants: New Horizon in Implant Dentistry.

PubMed

Jain, Neha; Gulati, Manisha; Garg, Meenu; Pathak, Chetan

2016-09-01

The choice of implant length is an essential factor in deciding the survival rates of these implants and the overall success of the prosthesis. Placing an implant in the posterior part of the maxilla and mandible has always been very critical due to poor bone quality and quantity. Long implants can be placed in association with complex surgical procedures such as sinus lift and bone augmentation. These techniques are associated with higher cost, increased treatment time and greater morbidity. Hence, there is need for a less invasive treatment option in areas of poor bone quantity and quality. Data related to survival rates of short implants, their design and prosthetic considerations has been compiled and structured in this manuscript with emphasis on the indications, advantages of short implants and critical biomechanical factors to be taken into consideration when choosing to place them. Studies have shown that comparable success rates can be achieved with short implants as those with long implants by decreasing the lateral forces to the prosthesis, eliminating cantilevers, increasing implant surface area and improving implant to abutment connection. Short implants can be considered as an effective treatment alternative in resorbed ridges. Short implants can be considered as a viable treatment option in atrophic ridge cases in order to avoid complex surgical procedures required to place long implants. With improvement in the implant surface geometry and surface texture, there is an increase in the bone implant contact area which provides a good primary stability during osseo-integration.

Short Implants: New Horizon in Implant Dentistry

PubMed Central

Gulati, Manisha; Garg, Meenu; Pathak, Chetan

2016-01-01

The choice of implant length is an essential factor in deciding the survival rates of these implants and the overall success of the prosthesis. Placing an implant in the posterior part of the maxilla and mandible has always been very critical due to poor bone quality and quantity. Long implants can be placed in association with complex surgical procedures such as sinus lift and bone augmentation. These techniques are associated with higher cost, increased treatment time and greater morbidity. Hence, there is need for a less invasive treatment option in areas of poor bone quantity and quality. Data related to survival rates of short implants, their design and prosthetic considerations has been compiled and structured in this manuscript with emphasis on the indications, advantages of short implants and critical biomechanical factors to be taken into consideration when choosing to place them. Studies have shown that comparable success rates can be achieved with short implants as those with long implants by decreasing the lateral forces to the prosthesis, eliminating cantilevers, increasing implant surface area and improving implant to abutment connection. Short implants can be considered as an effective treatment alternative in resorbed ridges. Short implants can be considered as a viable treatment option in atrophic ridge cases in order to avoid complex surgical procedures required to place long implants. With improvement in the implant surface geometry and surface texture, there is an increase in the bone implant contact area which provides a good primary stability during osseo-integration. PMID:27790598

Study of quiet turbofan STOL aircraft for short-haul transportation. Volume 2: Aircraft

NASA Technical Reports Server (NTRS)

1973-01-01

A study of the quiet turbofan STOL aircraft for short haul transportation was conducted. The objectives of the study were as follows: (1) to determine the relationships between STOL characteristics and economic and social viability of short haul air transportation, (2) to identify critical technology problems involving introduction of STOL short haul systems, (3) to define representative aircraft configurations, characteristics, and costs, and (4) to identify high payoff technology areas to improve STOL systems. The analyses of the aircraft designs which were generated to fulfill the objectives are summarized. The baseline aircraft characteristics are documented and significant trade studies are presented.

The Young Adult and Intellectual Freedom in the Library. A Selective Bibliography and Critical Review of the Literature.

ERIC Educational Resources Information Center

Squyres, Linda Lawrence

Designed for librarians planning community oriented programs, this annotated bibliography critically reviews literature defending the young adult's right to intellectual freedom. Works examined include U.S. English language journal articles and short sections of books published between 1967 and 1979. Within the bibliography and the review, topical…

Critical Education for Systemic Change: A World-Systems Analysis Perspective

ERIC Educational Resources Information Center

Griffiths, Tom G.

2015-01-01

This paper both draws on, and seeks to apply, world-systems analysis to a broad, critical education project that builds mass schooling's potential contribution to the process of world-systemic change. In short, this is done by first setting out the world-systems analysis account of the current state, and period of transition, of the capitalist…

Does a single gait training session performed either overground or on a treadmill induce specific short-term effects on gait parameters in patients with hemiparesis? A randomized controlled study.

PubMed

Bonnyaud, Céline; Pradon, Didier; Zory, Raphael; Bensmail, Djamel; Vuillerme, Nicolas; Roche, Nicolas

2013-01-01

Gait training for patients with hemiparesis is carried out independently overground or on a treadmill. Several studies have shown differences in hemiparetic gait parameters during overground versus treadmill walking. However, few studies have compared the effects of these 2 gait training conditions on gait parameters, and no study has compared the short-term effects of these techniques on all biomechanical gait parameters. To determine whether a gait training session performed overground or on a treadmill induces specific short-term effects on biomechanical gait parameters in patients with hemiparesis. Twenty-six subjects with hemiparesis were randomly assigned to a single session of either overground or treadmill gait training. The short-term effects on spatiotemporal, kinematic, and kinetic gait parameters were assessed using gait analysis before and immediately after the training and after a 20-minute rest. Speed, cadence, percentage of single support phase, peak knee extension, peak propulsion, and braking on the paretic side were significantly increased after the gait training session. However, there were no specific changes dependent on the type of gait training performed (overground or on a treadmill). A gait training session performed by subjects with hemiparesis overground or on a treadmill did not induce specific short-term effects on biomechanical gait parameters. The increase in gait velocity that followed a gait training session seemed to reflect specific modifications of the paretic lower limb and adaptation of the nonparetic lower limb.

The Role of the Hippocampus in Retaining Relational Information across Short Delays: The Importance of Memory Load

ERIC Educational Resources Information Center

Jeneson, Annette; Mauldin, Kristin N.; Hopkins, Ramona O.; Squire, Larry R.

2011-01-01

Patients with hippocampal damage are sometimes impaired at remembering information across delays as short as a few seconds. How are these impairments to be understood? One possibility is that retention of some kinds of information is critically dependent on the hippocampus, regardless of the retention interval and regardless of whether the task…

"Neither Can They Die Any More; for They Are Equal Unto the Angels": Secular Epiphanies in David Almond's "Counting Stars"

ERIC Educational Resources Information Center

Grace, Deborah

2014-01-01

Written before the successful publication of Skellig (1998), David Almond's short story collection, "Counting Stars," has attracted less critical attention than his more famous novels. Falling between fiction and autobiography, the earlier short stories are more firmly grounded in realism than the novels, which feature elements of…

Forest and grassland carbon in North America: A short course for land managers

Treesearch

Chris Swanston; Michael J. Furniss; Kristen Schmitt; Jeffrey Guntle; Maria Janowiak; Sarah Hines

2012-01-01

This multimedia short-course presents a range of information on the science, management and policy of forest and grassland carbon. Forests and grasslands worldwide play a critical role in storing carbon and sequestering greenhouse gases from the atmosphere. The U.S. Forest Service, which manages 193 million acres of forests and grasslands, emphasizes the need for...

The Short-Term Effectiveness of a Suicide Prevention Gatekeeper Training Program in a College Setting with Residence Life Advisers

ERIC Educational Resources Information Center

Tompkins, Tanya L.; Witt, Jody

2009-01-01

Although the college years prove to be a vulnerable time for students and a critical period for suicide prevention, few school-based prevention strategies have been empirically evaluated. The current study examined the short-term effects of Question, Persuade, and Refer (QPR), a gatekeeper training program that teaches how to recognize warning…

A single-laboratory validated method for the generation of DNA barcodes for the identification of fish for regulatory compliance.

PubMed

Handy, Sara M; Deeds, Jonathan R; Ivanova, Natalia V; Hebert, Paul D N; Hanner, Robert H; Ormos, Andrea; Weigt, Lee A; Moore, Michelle M; Yancy, Haile F

2011-01-01

The U.S. Food and Drug Administration is responsible for ensuring that the nation's food supply is safe and accurately labeled. This task is particularly challenging in the case of seafood where a large variety of species are marketed, most of this commodity is imported, and processed product is difficult to identify using traditional morphological methods. Reliable species identification is critical for both foodborne illness investigations and for prevention of deceptive practices, such as those where species are intentionally mislabeled to circumvent import restrictions or for resale as species of higher value. New methods that allow accurate and rapid species identifications are needed, but any new methods to be used for regulatory compliance must be both standardized and adequately validated. "DNA barcoding" is a process by which species discriminations are achieved through the use of short, standardized gene fragments. For animals, a fragment (655 base pairs starting near the 5' end) of the cytochrome c oxidase subunit 1 mitochondrial gene has been shown to provide reliable species level discrimination in most cases. We provide here a protocol with single-laboratory validation for the generation of DNA barcodes suitable for the identification of seafood products, specifically fish, in a manner that is suitable for FDA regulatory use.

A systems biology, whole-genome association analysis of the molecular regulation of biomass growth and composition in Populus deltoides

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

Kirst, Matias

2015-04-15

Poplars trees are well suited for biofuel production due to their fast growing habit, favorable wood composition and adaptation to a broad range of environments. The availability of a reference genome sequence, ease of vegetative propagation and availability of transformation methods also make poplar an ideal model for the study of wood formation and biomass growth in woody, perennial plants. The objective of this project was to conduct a genome-wide association genetics study to identify genes that regulate bioenergy traits in Populus deltoides (eastern cottonwood). Populus deltoides is a genetically diverse keystone forest species in North America and an importantmore » short rotation woody crop for the bioenergy industry. We searched for associations between eight growth and wood composition traits and common and low-frequency single-nucleotide polymorphisms (SNPs) detected by targeted resequencing of 18,153 genes in a population of 391 unrelated individuals. To increase power to detect associations with low-frequency variants, multiple-marker association tests were used in combination with single-marker association tests. Significant associations were discovered for all phenotypes and are indicative that low-frequency polymorphisms contribute to phenotypic variance of several bioenergy traits. These polymorphism are critical tools for the development of specialized plant feedstocks for bioenergy.« less

A systems biology, whole-genome association analysis of the molecular regulation of biomass growth and composition in Populus deltoides

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

Kirst, Matias

2014-04-14

Poplars trees are well suited for biofuel production due to their fast growing habit, favorable wood composition and adaptation to a broad range of environments. The availability of a reference genome sequence, ease of vegetative propagation and availability of transformation methods also make poplar an ideal model for the study of wood formation and biomass growth in woody, perennial plants. The objective of this project was to conduct a genome-wide association genetics study to identify genes that regulate bioenergy traits in Populus deltoides (eastern cottonwood). Populus deltoides is a genetically diverse keystone forest species in North America and an importantmore » short rotation woody crop for the bioenergy industry. We searched for associations between eight growth and wood composition traits and common and low-frequency single-nucleotide polymorphisms (SNPs) detected by targeted resequencing of 18,153 genes in a population of 391 unrelated individuals. To increase power to detect associations with low-frequency variants, multiple-marker association tests were used in combination with single-marker association tests. Significant associations were discovered for all phenotypes and are indicative that low-frequency polymorphisms contribute to phenotypic variance of several bioenergy traits. These polymorphism are critical tools for the development of specialized plant feedstocks for bioenergy.« less

MHD work related to a self-cooled Pb-17Li blanket with poloidal-radial-toroidal ducts

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

Reimann, J.; Barleon, L.; Buehler, L.

1994-12-31

For self cooled liquid metal blankets MHD pressure drop and velocity distributions are considered as critical issues. This paper summarizes MHD work performed for a DEMO-relevant Pb-17Li blanket which uses essential characteristics of a previous ANL design: The coolant flows downwards in the rear poloidal ducts, turns by 180{degrees} at the blanket bottom and is distributed from the ascending poloidal ducts into short radial channels which feed the toroidal First Wall coolant ducts (aligned with the main magnetic field direction). The flow through the subsequent radial channels is collected again in poloidal channels and the coolant leaves the blanket segmentmore » at the top. The blanket design is based on the use of flow channel inserts (FCIs) (which means electrically thin conducting walls for MHD) for all ducts except for the toroidal FW coolant channels. MHD related issues were defined and estimations of corresponding pressure drops were performed. Previous experimental work included a proof of principle of FCIs and a detailed experiment with a single {open_quotes}poloidal{sm_bullet}toroidal{sm_bullet}poloidal{close_quotes} duct (cooperation with ANL). In parallel, a numerical code based on the Core Flow Approximation (CFA) was developed to predict pressure drop and velocity distributions for arbitrary single duct geometries.« less

Multimodality Imaging of RNA Interference

PubMed Central

Nayak, Tapas R.; Krasteva, Lazura K.; Cai, Weibo

2013-01-01

The discovery of small interfering RNAs (siRNAs) and their potential to knock down virtually any gene of interest has ushered in a new era of RNA interference (RNAi). Clinical use of RNAi faces severe limitations due to inefficiency delivery of siRNA or short hairpin RNA (shRNA). Many molecular imaging techniques have been adopted in RNAi-related research for evaluation of siRNA/shRNA delivery, biodistribution, pharmacokinetics, and the therapeutic effect. In this review article, we summarize the current status of in vivo imaging of RNAi. The molecular imaging techniques that have been employed include bioluminescence/fluorescence imaging, magnetic resonance imaging/spectroscopy, positron emission tomography, single-photon emission computed tomography, and various combinations of these techniques. Further development of non-invasive imaging strategies for RNAi, not only focusing on the delivery of siRNA/shRNA but also the therapeutic efficacy, is critical for future clinical translation. Rigorous validation will be needed to confirm that biodistribution of the carrier is correlated with that of siRNA/shRNA, since imaging only detects the label (e.g. radioisotopes) but not the gene or carrier themselves. It is also essential to develop multimodality imaging approaches for realizing the full potential of therapeutic RNAi, as no single imaging modality may be sufficient to simultaneously monitor both the gene delivery and silencing effect of RNAi. PMID:23745567

Two new endangered species of Anomaloglossus (Anura: Aromobatidae) from Roraima State, northern Brazil.

PubMed

Fouquet, Antoine; Souza, Sergio Marques; Nunes, Pedro M Sales; Kok, Philippe J R; Curcio, Felipe Franco; De Carvalho, Celso Morato; Grant, Taran; Rodrigues, Miguel Trefaut

2015-03-05

We describe two new species of Anomaloglossus from Roraima State, Brazil, that are likely endemic to single mountains currently isolated among lowland forest and savanna ecosystems. The first species, Anomaloglossus tepequem sp. nov. was collected in 1986 and 1992 along a single stream at >500 m elevation on a tepui-like mountain named Tepequém, but was not detected during recent investigations. It is mainly diagnosed from other Anomaloglossus species by its well developed foot webbing, immaculate cream abdomen colouration and small body size (males: 18.2-20.1 mm, females: 21.7-24.5). The second species, Anomaloglossus apiau sp. nov. was found along several streams between 500 and 1400 m elevation on Serra do Apiaú, and is mainly diagnosed from congeners by its weakly webbed feet, males with swollen third finger and ventrolateral stripe formed by white dots, and its advertisement call; a long trill (up to almost 40 s) consisting of pairs of very short pulses. The discovery of these two apparently microendemic species suggests that additional Anomaloglossus species remain to be described in the Guiana Shield. Both species should be considered critically endangered given their seemingly reduced range size, association with highland habitat, and the anthropogenic pressure they currently face.

Genome-wide association study reveals putative regulators of bioenergy traits in Populus deltoides

DOE PAGES

Fahrenkrog, Annette M.; Neves, Leandro G.; Resende, Jr., Marcio F. R.; ...

2016-09-06

Genome-wide association studies (GWAS) have been used extensively to dissect the genetic regulation of complex traits in plants. These studies have focused largely on the analysis of common genetic variants despite the abundance of rare polymorphisms in several species, and their potential role in trait variation. Here, we conducted the first GWAS in Populus deltoides, a genetically diverse keystone forest species in North America and an important short rotation woody crop for the bioenergy industry. We searched for associations between eight growth and wood composition traits, and common and low-frequency single-nucleotide polymorphisms detected by targeted resequencing of 18 153 genesmore » in a population of 391 unrelated individuals. To increase power to detect associations with low-frequency variants, multiple-marker association tests were used in combination with single-marker association tests. Significant associations were discovered for all phenotypes and are indicative that low-frequency polymorphisms contribute to phenotypic variance of several bioenergy traits. Our results suggest that both common and low-frequency variants need to be considered for a comprehensive understanding of the genetic regulation of complex traits, particularly in species that carry large numbers of rare polymorphisms. Lastly, these polymorphisms may be critical for the development of specialized plant feedstocks for bioenergy.« less

Separation of coal-tar constituents from soil particles in a two-liquid-phase slurry system.

PubMed

Schuur, J H Berg; Mattiasson, B

2003-06-01

An evaluation has been made of the capability of rapeseed oil to dissolve polycyclic aromatic hydrocarbon (PAH) crystals in a biphasic system and of its capability to extract PAHs from polluted soil in a two-liquid-phase (TLP) slurry system. Up to 220 g l(-1) of the crystalline hydrocarbons could be dissolved in the organic phase, indicating oil/water-partitioning coefficients of 10(5). When soil from a former gasworks site was treated in a TLP slurry system, it was found that a certain critical amount of vegetable oil had to be added in order to form a free oil phase. Single and multiple extractions gave similar results for multiple short-term and single long-term treatments, with a maximum of 87% for pyrene release. Following a 30-day bioslurry treatment, the total concentration of the 16 EPA PAHs in the soil decreased from 2740 mg kg(-1) to 1366 mg kg(-1). This was followed by one of three different 12-day post-bioslurry treatments. Further bioslurry treatment reduced the final concentration to 1002 mg kg(-1). Abiotic treatment with a surfactant (Brij 30) achieved a reduction to 797 mg kg(-1). Treatment with rapeseed oil gave the best reduction to 343 mg kg(-1).

Single residue substitutions that change the gating properties of a mechanosensitive channel in Escherichia coli

NASA Technical Reports Server (NTRS)

Blount, P.; Sukharev, S. I.; Schroeder, M. J.; Nagle, S. K.; Kung, C.

1996-01-01

MscL is a channel that opens a large pore in the Escherichia coli cytoplasmic membrane in response to mechanical stress. Previously, we highly enriched the MscL protein by using patch clamp as a functional assay and cloned the corresponding gene. The predicted protein contains a largely hydrophobic core spanning two-thirds of the molecule and a more hydrophilic carboxyl terminal tail. Because MscL had no homology to characterized proteins, it was impossible to predict functional regions of the protein by simple inspection. Here, by mutagenesis, we have searched for functionally important regions of this molecule. We show that a short deletion from the amino terminus (3 amino acids), and a larger deletion of 27 amino acids from the carboxyl terminus of this protein, had little if any effect in channel properties. We have thus narrowed the search of the core mechanosensitive mechanism to 106 residues of this 136-amino acid protein. In contrast, single residue substitutions of a lysine in the putative first transmembrane domain or a glutamine in the periplasmic loop caused pronounced shifts in the mechano-sensitivity curves and/or large changes in the kinetics of channel gating, suggesting that the conformational structure in these regions is critical for normal mechanosensitive channel gating.

Single residue substitutions that change the gating properties of a mechanosensitive channel in Escherichia coli.

PubMed Central

Blount, P; Sukharev, S I; Schroeder, M J; Nagle, S K; Kung, C

1996-01-01

MscL is a channel that opens a large pore in the Escherichia coli cytoplasmic membrane in response to mechanical stress. Previously, we highly enriched the MscL protein by using patch clamp as a functional assay and cloned the corresponding gene. The predicted protein contains a largely hydrophobic core spanning two-thirds of the molecule and a more hydrophilic carboxyl terminal tail. Because MscL had no homology to characterized proteins, it was impossible to predict functional regions of the protein by simple inspection. Here, by mutagenesis, we have searched for functionally important regions of this molecule. We show that a short deletion from the amino terminus (3 amino acids), and a larger deletion of 27 amino acids from the carboxyl terminus of this protein, had little if any effect in channel properties. We have thus narrowed the search of the core mechanosensitive mechanism to 106 residues of this 136-amino acid protein. In contrast, single residue substitutions of a lysine in the putative first transmembrane domain or a glutamine in the periplasmic loop caused pronounced shifts in the mechano-sensitivity curves and/or large changes in the kinetics of channel gating, suggesting that the conformational structure in these regions is critical for normal mechanosensitive channel gating. Images Fig. 3 PMID:8876191

Growth Mechanism Studies of ZnO Nanowires: Experimental Observations and Short-Circuit Diffusion Analysis

PubMed Central

Shih, Po-Hsun

2017-01-01

Plenty of studies have been performed to probe the diverse properties of ZnO nanowires, but only a few have focused on the physical properties of a single nanowire since analyzing the growth mechanism along a single nanowire is difficult. In this study, a single ZnO nanowire was synthesized using a Ti-assisted chemical vapor deposition (CVD) method to avoid the appearance of catalytic contamination. Two-dimensional energy dispersive spectroscopy (EDS) mapping with a diffusion model was used to obtain the diffusion length and the activation energy ratio. The ratio value is close to 0.3, revealing that the growth of ZnO nanowires was attributed to the short-circuit diffusion. PMID:28754030

Efficient optical pulse stacker system

DOEpatents

Seppala, Lynn G.; Haas, Roger A.

1982-01-01

Method and apparatus for spreading and angle-encoding each pulse of a multiplicity of small area, short pulses into several temporally staggered pulses by use of appropriate beam splitters, with the optical elements being arranged so that each staggered pulse is contiguous with one or two other such pulses, and the entire sequence of stacked pulses comprising a single, continuous long pulse. The single long pulse is expanded in area, and then doubly passed through a nonstorage laser amplifier such as KrF. After amplification, the physically separated, angle-encoded and temporally staggered pulses are recombined into a single pulse of short duration. This high intensity output beam is well collimated and may be propagated over long distance, or used for irradiating inertial confinement fusion targets.

Effects of binary stellar populations on direct collapse black hole formation

NASA Astrophysics Data System (ADS)

Agarwal, Bhaskar; Cullen, Fergus; Khochfar, Sadegh; Klessen, Ralf S.; Glover, Simon C. O.; Johnson, Jarrett

2017-06-01

The critical Lyman-Werner (LW) flux required for direct collapse blackholes (DCBH) formation, or Jcrit, depends on the shape of the irradiating spectral energy distribution (SED). The SEDs employed thus far have been representative of realistic single stellar populations. We study the effect of binary stellar populations on the formation of DCBH, as a result of their contribution to the LW radiation field. Although binary populations with ages > 10 Myr yield a larger LW photon output, we find that the corresponding values of Jcrit can be up to 100 times higher than single stellar populations. We attribute this to the shape of the binary SEDs as they produce a sub-critical rate of H- photodetaching 0.76 eV photons as compared to single stellar populations, reaffirming the role that H- plays in DCBH formation. This further corroborates the idea that DCBH formation is better understood in terms of a critical region in the H2-H- photodestruction rate parameter space, rather than a single value of LW flux.

Human mismatch repair protein hMutLα is required to repair short slipped-DNAs of trinucleotide repeats.

PubMed

Panigrahi, Gagan B; Slean, Meghan M; Simard, Jodie P; Pearson, Christopher E

2012-12-07

Mismatch repair (MMR) is required for proper maintenance of the genome by protecting against mutations. The mismatch repair system has also been implicated as a driver of certain mutations, including disease-associated trinucleotide repeat instability. We recently revealed a requirement of hMutSβ in the repair of short slip-outs containing a single CTG repeat unit (1). The involvement of other MMR proteins in short trinucleotide repeat slip-out repair is unknown. Here we show that hMutLα is required for the highly efficient in vitro repair of single CTG repeat slip-outs, to the same degree as hMutSβ. HEK293T cell extracts, deficient in hMLH1, are unable to process single-repeat slip-outs, but are functional when complemented with hMutLα. The MMR-deficient hMLH1 mutant, T117M, which has a point mutation proximal to the ATP-binding domain, is defective in slip-out repair, further supporting a requirement for hMLH1 in the processing of short slip-outs and possibly the involvement of hMHL1 ATPase activity. Extracts of hPMS2-deficient HEC-1-A cells, which express hMLH1, hMLH3, and hPMS1, are only functional when complemented with hMutLα, indicating that neither hMutLβ nor hMutLγ is sufficient to repair short slip-outs. The resolution of clustered short slip-outs, which are poorly repaired, was partially dependent upon a functional hMutLα. The joint involvement of hMutSβ and hMutLα suggests that repeat instability may be the result of aberrant outcomes of repair attempts.

Structural, magnetothermal, and magnetotransport properties of single crystal terbium silicon germanide and spontaneous generation of voltage in single crystal gadolinium silicon germanide and gadolinium

NASA Astrophysics Data System (ADS)

Zou, Min

A systematic study of single crystalline Tb5Si2.2Ge1.8, including magnetic field induced crystallographic and magnetic phase transformations, magnetocaloric effect, ferromagnetic short-range correlations, electrical resistivity, magnetoresistance, and spontaneous generation of voltage (SGV) has been presented. A study of SGV in single crystalline Gd5Si2Ge2 and Gd has also been included. The metamagnetic-like transitions and giant magnetocaloric effect were observed with the magnetic field applied parallel to the a- and c-axes, but not the b-axis in a Tb5Si 2.2Ge1.8 single crystal. The in-situ x-ray powder diffraction study indicates that these metamagnetic-like transitions are coupled to a crystallographic phase transformation occurring via strong magnetoelastic interactions. The magnetocrystalline anisotropy plays an important role in this system. Magnetic fields less than 40 kOe can not drive either the magnetic or the crystallographic phase transition to completion for Tb5Si2.2Ge1.8 powder due to the strong single ion anisotropy of Tb. Magnetic field dependencies of the critical temperatures of magnetic phase transitions of Tb5Si2.2Ge1.8 are highly anisotropic for both the main magnetic ordering process occurring around 120 K and a spin reorientation transition at ~70 K. Magnetic-field-induced phase transitions occur with the magnetic field applied isothermally along the a-and b-axes (but not along the c-axis) between 1.8 and 70 K in fields below 70 kOe. Strongly anisotropic thermal irreversibility is observed in the Griffiths phase regime between 120 and 200 K with applied fields ranging from 10 to 1000 Oe. Our data: (1) show that the magnetic and structural phase transitions around 120 K are narrowly decoupled; (2) uncover the anisotropy of ferromagnetic short-range order in the Griffiths phase; and (3) reveal some unusual magnetic domain effects in the long-range ordered state of the Tb5Si2.2Ge1.8 compound. The temperature-magnetic field phase diagrams with field applied along the three major crystallographic directions have been constructed. The positive colossal magnetoresistance (CMR) with a magnitude of ~150% was observed with the magnetic field applied parallel to the a-axis, but not the b- and c-axes in Tb5Si 2.2Ge1.8 single crystals. The electrical resistivity shows a low-temperature high-resistivity behavior (i.e. the resistivity at low temperature is higher after the transformation to the low temperature phase than the resistivity of the phase before the transition) along the a-axis, contrary to those along the b- and c-axes. The positive CMR effect originates from an intrinsic crystallographic phase coexistence state frozen below the Curie Temperature (TC). The differences in the temperature dependencies of electrical resistivities and longitudinal magnetoresistance along the a-axis and those along the b- and c-axes can be explained by the geometry of the phase boundaries at low temperatures, and the inability of the external magnetic field to induce the crystallographic phase transformation along the b- and c-axes. Temperature-induced SGVs were observed along all three principal crystallographic axes of Tb5Si2.2Ge1.8, but not in Gd. Field-induced SGVs were observed with magnetic fields less than 40 kOe applied along the a-axis of Tb5Si2.2Ge1.8, and the c-axis of Gd. The absence of the temperature induced SGV in Gd indicates the key role first-order phase transformations play in the appearance of the effect when temperature varies. The anisotropy of magnetic field induced SGV in Tb5Si2.2Ge1.8 and the existence of field induced SGV in Gd, highlight the importance of the magnetocaloric effect in bringing about the SGV. In single crystal and polycrystalline Gd5Si 2Ge2 during the coupled magneto-structural transformations, reversible and repeatable SGV responses of the materials to the temperature and magnetic field have been observed. The parameters of the response and the magnitude of the signal are anisotropic and rate dependent. The magnitude of the SGV signal, and the critical temperatures and critical magnetic fields at which the SGV occurs vary with the rate of temperature and magnetic field changes.

Single Subject Research: Applications to Special Education

ERIC Educational Resources Information Center

Cakiroglu, Orhan

2012-01-01

Single subject research is a scientific research methodology that is increasingly used in the field of special education. Therefore, understanding the unique characteristics of single subject research methodology is critical both for educators and practitioners. Certain characteristics make single subject research one of the most preferred…

Modelling single shot damage thresholds of multilayer optics for high-intensity short-wavelength radiation sources.

PubMed

Loch, R A; Sobierajski, R; Louis, E; Bosgra, J; Bijkerk, F

2012-12-17

The single shot damage thresholds of multilayer optics for high-intensity short-wavelength radiation sources are theoretically investigated, using a model developed on the basis of experimental data obtained at the FLASH and LCLS free electron lasers. We compare the radiation hardness of commonly used multilayer optics and propose new material combinations selected for a high damage threshold. Our study demonstrates that the damage thresholds of multilayer optics can vary over a large range of incidence fluences and can be as high as several hundreds of mJ/cm(2). This strongly suggests that multilayer mirrors are serious candidates for damage resistant optics. Especially, multilayer optics based on Li(2)O spacers are very promising for use in current and future short-wavelength radiation sources.

Training Select-in Interviewers for Astronaut Selection: A Program Evaluation

NASA Technical Reports Server (NTRS)

Hysong, S.; Galarza, L.; Holland, A.; Billica, Roger (Technical Monitor)

2000-01-01

Psychological factors critical to the success of short and long-duration missions have been identified in previous research; however, evaluation for such critical factors in astronaut applicants leaves much room for human interpretation. Thus, an evaluator training session was designed to standardize the interpretation of critical factors, as well as the structure of the select-in interview across evaluators. The purpose of this evaluative study was to determine the effectiveness of the evaluator training sessions and their potential impact on evaluator ratings.

Age of Red Cells for Transfusion and Outcomes in Critically Ill Adults.

PubMed

Cooper, D James; McQuilten, Zoe K; Nichol, Alistair; Ady, Bridget; Aubron, Cécile; Bailey, Michael; Bellomo, Rinaldo; Gantner, Dashiell; Irving, David O; Kaukonen, Kirsi-Maija; McArthur, Colin; Murray, Lynne; Pettilä, Ville; French, Craig

2017-11-09

It is uncertain whether the duration of red-cell storage affects mortality after transfusion among critically ill adults. In an international, multicenter, randomized, double-blind trial, we assigned critically ill adults to receive either the freshest available, compatible, allogeneic red cells (short-term storage group) or standard-issue (oldest available), compatible, allogeneic red cells (long-term storage group). The primary outcome was 90-day mortality. From November 2012 through December 2016, at 59 centers in five countries, 4994 patients underwent randomization and 4919 (98.5%) were included in the primary analysis. Among the 2457 patients in the short-term storage group, the mean storage duration was 11.8 days. Among the 2462 patients in the long-term storage group, the mean storage duration was 22.4 days. At 90 days, there were 610 deaths (24.8%) in the short-term storage group and 594 (24.1%) in the long-term storage group (absolute risk difference, 0.7 percentage points; 95% confidence interval [CI], -1.7 to 3.1; P=0.57). At 180 days, the absolute risk difference was 0.4 percentage points (95% CI, -2.1 to 3.0; P=0.75). Most of the prespecified secondary measures showed no significant between-group differences in outcome. The age of transfused red cells did not affect 90-day mortality among critically ill adults. (Funded by the Australian National Health and Medical Research Council and others; TRANSFUSE Australian and New Zealand Clinical Trials Registry number, ACTRN12612000453886 ; ClinicalTrials.gov number, NCT01638416 .).

Lower critical field measurements in YBa2Cu3O(6+x) single crystals

NASA Technical Reports Server (NTRS)

Kaiser, D. L.; Swartzendruber, L. J.; Gayle, F. W.; Bennett, L. H.

1991-01-01

The temperature dependence of the lower critical field in YBa2Cu3O(6+x) single crystals was determined by magnetization measurements with the applied field parallel and perpendicular to the c-axis. Results are compared with data from the literature and fitted to Ginzberg-Landau equations by assuming a linear dependence of the parameter kappa on temperature. A value of 7 plus or minus 2 kOe was estimated for the thermodynamic critical field at T = O by comparison of calculated H (sub c2) values with experimental data from the literature.

A Long Look at the Short Film

ERIC Educational Resources Information Center

Miller, Franklin, Jr.

1971-01-01

The history of the short film and the single concept film loop is presented. Lists fourteen reasons why it may be necessary to make and use a film loop. Film loop projectors are analyzed according to present features and deficiencies with predictions on future improvements. (DS)

Using paid mass media to teach the warning signs of stroke: the long and the short of it.

PubMed

Hodgson, Corinne; Lindsay, Patrice; Rubini, Frank

2009-04-01

Stroke is a major cause of morbidity and mortality and rapid treatment is critical to patient outcomes. This paper looks at the effect of paid television advertising campaigns upon the general public's knowledge of the warning signs of stroke and emergency department (ED) stroke presentations. Data for the study includes results of nine random-digit dialing telephone surveys conducted among Ontario adults aged 45 and over. The mean number of ED presentations for all strokes and for transient ischemic attacks (TIA) were obtained from the Registry of the Canadian Stroke Network (RCSN). Polls indicated that long advertising campaigns were associated with significant increases in the public's knowledge of stroke warning signs, while shorter campaigns were associated with much smaller increases. Time (as represented by month) was the single most important factor determining the mean number of ED presentations for total stroke but was not for TIAs. Campaign status (on or off the air) had a strong and significant effect on ED presentations when the advertising campaigns were long; when the advertising campaigns were shortened, there was no campaign effect. Long, intermittent campaigns are effective in increasing the public's awareness of the warning signs of stroke and may have a significant effect on ED presentations for stroke and TIA. Public awareness of stroke warning signs declines during advertising black-outs, so short campaigns are less effective.

Critical neural networks with short- and long-term plasticity.

PubMed

Michiels van Kessenich, L; Luković, M; de Arcangelis, L; Herrmann, H J

2018-03-01

In recent years self organized critical neuronal models have provided insights regarding the origin of the experimentally observed avalanching behavior of neuronal systems. It has been shown that dynamical synapses, as a form of short-term plasticity, can cause critical neuronal dynamics. Whereas long-term plasticity, such as Hebbian or activity dependent plasticity, have a crucial role in shaping the network structure and endowing neural systems with learning abilities. In this work we provide a model which combines both plasticity mechanisms, acting on two different time scales. The measured avalanche statistics are compatible with experimental results for both the avalanche size and duration distribution with biologically observed percentages of inhibitory neurons. The time series of neuronal activity exhibits temporal bursts leading to 1/f decay in the power spectrum. The presence of long-term plasticity gives the system the ability to learn binary rules such as xor, providing the foundation of future research on more complicated tasks such as pattern recognition.

Critical neural networks with short- and long-term plasticity

NASA Astrophysics Data System (ADS)

Michiels van Kessenich, L.; Luković, M.; de Arcangelis, L.; Herrmann, H. J.

2018-03-01

In recent years self organized critical neuronal models have provided insights regarding the origin of the experimentally observed avalanching behavior of neuronal systems. It has been shown that dynamical synapses, as a form of short-term plasticity, can cause critical neuronal dynamics. Whereas long-term plasticity, such as Hebbian or activity dependent plasticity, have a crucial role in shaping the network structure and endowing neural systems with learning abilities. In this work we provide a model which combines both plasticity mechanisms, acting on two different time scales. The measured avalanche statistics are compatible with experimental results for both the avalanche size and duration distribution with biologically observed percentages of inhibitory neurons. The time series of neuronal activity exhibits temporal bursts leading to 1 /f decay in the power spectrum. The presence of long-term plasticity gives the system the ability to learn binary rules such as xor, providing the foundation of future research on more complicated tasks such as pattern recognition.

Transarterial onyx embolization of cranial dural arteriovenous fistulas: long-term follow-up.

PubMed

Chandra, R V; Leslie-Mazwi, T M; Mehta, B P; Yoo, A J; Rabinov, J D; Pryor, J C; Hirsch, J A; Nogueira, R G

2014-09-01

Endovascular therapy with liquid embolic agents is a common treatment strategy for cranial dural arteriovenous fistulas. This study evaluated the long-term effectiveness of transarterial Onyx as the single embolic agent for curative embolization of noncavernous cranial dural arteriovenous fistulas. We performed a retrospective review of 40 consecutive patients with 41 cranial dural arteriovenous fistulas treated between March 2006 and June 2012 by using transarterial Onyx embolization with intent to cure. The mean age was 57 years; one-third presented with intracranial hemorrhage. Most (85%) had cortical venous drainage. Once angiographic cure was achieved, long-term treatment effectiveness was assessed with DSA and clinical follow-up. Forty-nine embolization sessions were performed; 85% of cranial dural arteriovenous fistulas were treated in a single session. The immediate angiographic cure rate was 95%. The permanent neurologic complication rate was 2% (mild facial palsy). Thirty-five of the 38 patients with initial cure underwent short-term follow-up DSA (median, 4 months). The short-term recurrence rate was only 6% (2/35). All patients with occlusion at short-term DSA undergoing long-term DSA (median, 28 months) had durable occlusion. No patient with long-term clinical follow-up (total, 117 patient-years; median, 45 months) experienced hemorrhage. Transarterial embolization with Onyx as the single embolic agent results in durable long-term cure of noncavernous cranial dural arteriovenous fistulas. Recurrence rates are low on short-term follow-up, and all patients with angiographic occlusion on short-term DSA follow-up have experienced a durable long-term cure. Thus, angiographic cure should be defined at short-term follow-up angiography instead of at the end of the final embolization session. Finally, long-term DSA follow-up may not be necessary if occlusion is demonstrated on short-term angiographic follow-up. © 2014 by American Journal of Neuroradiology.

Internal Short Circuits in Lithium-Ion Cells for PHEVs

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

Sriramulu, Suresh; Stringfellow, Richard

2013-05-25

Development of Plug-in Hybrid Electric Vehicles (PHEVs) has recently become a high national priority because of their potential to enable significantly reduced petroleum consumption by the domestic transportation sector in the relatively near term. Lithium-ion (Li-ion) batteries are a critical enabling technology for PHEVs. Among battery technologies with suitable operating characteristics for use in vehicles, Li-ion batteries offer the best combination of energy, power, life and cost. Consequently, worldwide, leading corporations and government agencies are supporting the development of Li-ion batteries for PHEVs, as well as the full spectrum of vehicular applications ranging from mild hybrid to all-electric. In thismore » project, using a combination of well-defined experiments, custom designed cells and simulations, we have improved the understanding of the process by which a Li-ion cell that develops an internal short progresses to thermal runaway. Using a validated model for thermal runaway, we have explored the influence of environmental factors and cell design on the propensity for thermal runaway in full-sized PHEV cells. We have also gained important perspectives about internal short development and progression; specifically that initial internal shorts may be augmented by secondary shorts related to separator melting. Even though the nature of these shorts is very stochastic, we have shown the critical and insufficiently appreciated role of heat transfer in influencing whether a developing internal short results in a thermal runaway. This work should lead to enhanced perspectives on separator design, the role of active materials and especially cathode materials with respect to safety and the design of automotive cooling systems to enhance battery safety in PHEVs.« less

Ashkin-Teller criticality and weak first-order behavior of the phase transition to a fourfold degenerate state in two-dimensional frustrated Ising antiferromagnets

NASA Astrophysics Data System (ADS)

Liu, R. M.; Zhuo, W. Z.; Chen, J.; Qin, M. H.; Zeng, M.; Lu, X. B.; Gao, X. S.; Liu, J.-M.

2017-07-01

We study the thermal phase transition of the fourfold degenerate phases (the plaquette and single-stripe states) in the two-dimensional frustrated Ising model on the Shastry-Sutherland lattice using Monte Carlo simulations. The critical Ashkin-Teller-like behavior is identified both in the plaquette phase region and the single-stripe phase region. The four-state Potts critical end points differentiating the continuous transitions from the first-order ones are estimated based on finite-size-scaling analyses. Furthermore, a similar behavior of the transition to the fourfold single-stripe phase is also observed in the anisotropic triangular Ising model. Thus, this work clearly demonstrates that the transitions to the fourfold degenerate states of two-dimensional Ising antiferromagnets exhibit similar transition behavior.

Aqueous Foam Stabilized by Tricationic Amphiphilic Surfactants

NASA Astrophysics Data System (ADS)

Heerschap, Seth; Marafino, John; McKenna, Kristin; Caran, Kevin; Feitosa, Klebert; Kevin Caran's Research Group Collaboration

2015-03-01

The unique surface properties of amphiphilic molecules have made them widely used in applications where foaming, emulsifying or coating processes are needed. The development of novel architectures with multi-cephalic/tailed molecules have enhanced their anti-bacterial activity in connection with tail length and the nature of the head group. Here we report on the foamability of two triple head double, tail cationic surfactants (M-1,14,14, M-P, 14,14) and a triple head single tail cationic surfactant (M-1,1,14) and compare them with commercially available single headed, single tailed anionic and cationic surfactants (SDS,CTAB and DTAB). The results show that bubble rupture rate decrease with the length of the carbon chain irrespective of head structure. The growth rate of bubbles with short tailed surfactants (SDS) and longer, single tailed tricationic surfactants (M-1,1,14) was shown to be twice as high as those with longer tailed surfactants (CTAB, M-P,14,14, M-1,14,14). This fact was related to the size variation of bubbles, where the foams made with short tail surfactants exhibited higher polydispersivity than those with short tails. This suggests that foams with tricationic amphiphilics are closed linked to their tail length and generally insensitive to their head structure.

Nonequilibrium phase diagram of a one-dimensional quasiperiodic system with a single-particle mobility edge

NASA Astrophysics Data System (ADS)

Purkayastha, Archak; Dhar, Abhishek; Kulkarni, Manas

2017-11-01

We investigate and map out the nonequilibrium phase diagram of a generalization of the well known Aubry-André-Harper (AAH) model. This generalized AAH (GAAH) model is known to have a single-particle mobility edge which also has an additional self-dual property akin to that of the critical point of the AAH model. By calculating the population imbalance, we get hints of a rich phase diagram. We also find a fascinating connection between single particle wave functions near the mobility edge of the GAAH model and the wave functions of the critical AAH model. By placing this model far from equilibrium with the aid of two baths, we investigate the open system transport via system size scaling of nonequilibrium steady state (NESS) current, calculated by fully exact nonequilibrium Green's function (NEGF) formalism. The critical point of the AAH model now generalizes to a `critical' line separating regions of ballistic and localized transport. Like the critical point of the AAH model, current scales subdiffusively with system size on the `critical' line (I ˜N-2 ±0.1 ). However, remarkably, the scaling exponent on this line is distinctly different from that obtained for the critical AAH model (where I ˜N-1.4 ±0.05 ). All these results can be understood from the above-mentioned connection between states near the mobility edge of the GAAH model and those of the critical AAH model. A very interesting high temperature nonequilibrium phase diagram of the GAAH model emerges from our calculations.

Critical behavior of the van der Waals bonded ferromagnet Fe 3 - x GeTe 2

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

Liu, Yu; Ivanovski, V. N.; Petrovic, C.

The critical properties of the single-crystalline van der Waals bonded ferromagnet Fe 3-xGeTe 2 were investigated by bulk dc magnetization around the paramagnetic to ferromagnetic (FM) phase transition. The Fe 3-xGeTe 2 single crystals grown by self-flux method with Fe deficiency x ≈ 0.36 exhibit bulk FM ordering below T c = 152 K. The Mössbauer spectroscopy was used to provide information on defects and local atomic environment in such crystals. Critical exponents β = 0.372(4) with a critical temperature T c= 151.25(5) K and γ = 1.265(15) with T c = 151.17(12) K are obtained by the Kouvel-Fisher method,more » whereas δ = 4.50 ( 1 ) is obtained by a critical isotherm analysis at T c = 151 K. These critical exponents obey the Widom scaling relation δ = 1 + γ / β , indicating self-consistency of the obtained values. With these critical exponents the isotherm M(H) curves below and above the critical temperatures collapse into two independent universal branches, obeying the single scaling equation m = f±(h), where m and h are renormalized magnetization and field, respectively. The exponents determined in this study are close to those calculated from the results of the renormalization group approach for a heuristic model of three-dimensional Heisenberg (d = 3,n = 3) spins coupled with the attractive long-range interactions between spins that decay as J(r) ≈ r -(3+σ) with σ = 1.89.« less

Critical behavior of the van der Waals bonded ferromagnet Fe 3 - x GeTe 2

DOE PAGES

Liu, Yu; Ivanovski, V. N.; Petrovic, C.

2017-10-29

The critical properties of the single-crystalline van der Waals bonded ferromagnet Fe 3-xGeTe 2 were investigated by bulk dc magnetization around the paramagnetic to ferromagnetic (FM) phase transition. The Fe 3-xGeTe 2 single crystals grown by self-flux method with Fe deficiency x ≈ 0.36 exhibit bulk FM ordering below T c = 152 K. The Mössbauer spectroscopy was used to provide information on defects and local atomic environment in such crystals. Critical exponents β = 0.372(4) with a critical temperature T c= 151.25(5) K and γ = 1.265(15) with T c = 151.17(12) K are obtained by the Kouvel-Fisher method,more » whereas δ = 4.50 ( 1 ) is obtained by a critical isotherm analysis at T c = 151 K. These critical exponents obey the Widom scaling relation δ = 1 + γ / β , indicating self-consistency of the obtained values. With these critical exponents the isotherm M(H) curves below and above the critical temperatures collapse into two independent universal branches, obeying the single scaling equation m = f±(h), where m and h are renormalized magnetization and field, respectively. The exponents determined in this study are close to those calculated from the results of the renormalization group approach for a heuristic model of three-dimensional Heisenberg (d = 3,n = 3) spins coupled with the attractive long-range interactions between spins that decay as J(r) ≈ r -(3+σ) with σ = 1.89.« less

Mutanlallemand (mtl) and Belly Spot and Deafness (bsd) Are Two New Mutations of Lmx1a Causing Severe Cochlear and Vestibular Defects

PubMed Central

Pearson, Selina; Brooker, Rachael H.; Spiden, Sarah; Kiernan, Amy E.; Guénet, Jean-Louis; Steel, Karen P.

2012-01-01

Mutanlallemand (mtl) and Belly Spot and Deafness (bsd) are two new spontaneous alleles of the Lmx1a gene in mice. Homozygous mutants show head tossing and circling behaviour, indicative of vestibular defects, and they have short tails and white belly patches of variable size. The analysis of auditory brainstem responses (ABR) showed that mtl and bsd homozygotes are deaf, whereas heterozygous and wildtype littermates have normal hearing. Paint-filled inner ears at E16.5 revealed that mtl and bsd homozygotes lack endolymphatic ducts and semicircular canals and have short cochlear ducts. These new alleles show similarities with dreher (Lmx1a) mutants. Complementation tests between mtl and dreher and between mtl and bsd suggest that mtl and bsd are new mutant alleles of the Lmx1a gene. To determine the Lmx1a mutation in mtl and bsd mutant mice we performed PCR followed by sequencing of genomic DNA and cDNA. The mtl mutation is a single point mutation in the 3′ splice site of exon 4 leading to an exon extension and the activation of a cryptic splice site 44 base pairs downstream, whereas the bsd mutation is a genomic deletion that includes exon 3. Both mutations lead to a truncated LMX1A protein affecting the homeodomain (mtl) or LIM2-domain (bsd), which is critical for LMX1A protein function. Moreover, the levels of Lmx1a transcript in mtl and bsd mutants are significantly down-regulated. Hmx2/3 and Pax2 expression are also down-regulated in mtl and bsd mutants, suggesting a role of Lmx1a upstream of these transcription factors in early inner ear morphogenesis. We have found that these mutants develop sensory patches although they are misshapen. The characterization of these two new Lmx1a alleles highlights the critical role of this gene in the development of the cochlea and vestibular system. PMID:23226461

Teacher as Learner: A Personal Reflection on a Short Course for South African University Educators

ERIC Educational Resources Information Center

Clowes, Lindsay

2013-01-01

Higher education is understood to play a critical role in ongoing processes of social transformation in post-apartheid South Africa through the production of graduates who are critical and engaged citizens. A key challenge is that institutions of higher education are themselves implicated in reproducing the very hierarchies they hope to transform.…

Critical current measurements of high-temperature superconducting short samples at a wide range of temperatures and magnetic fields.

PubMed

Ma, Hongjun; Liu, Huajun; Liu, Fang; Zhang, Huahui; Ci, Lu; Shi, Yi; Lei, Lei

2018-01-01

High-Temperature Superconductors (HTS) are potential materials for high-field magnets, low-loss transmission cables, and Superconducting Magnetic Energy Storage (SMES) due to their high upper critical magnetic field (H c2 ) and critical temperature (T c ). The critical current (I c ) of HTS, which is one of the most important parameters for superconductor application, depends strongly on the magnetic fields and temperatures. A new I c measurement system that can carry out accurate I c measurement for HTS short samples with various temperatures (4.2-80 K), magnetic fields (0-14 T), and angles of the magnetic field (0°-90°) has been developed. The I c measurement system mainly consists of a measurement holder, temperature-control system, background magnet, test cryostat, data acquisition system, and DC power supply. The accuracy of temperature control is better than ±0.1 K over the 20-80 K range and ±0.05 K when measured below 20 K. The maximum current is over 1000 A with a measurement uncertainty of 1%. The system had been successfully used for YBa 2 Cu 3 O 7-x (YBCO) tapes I c determination with different temperatures and magnetic fields.

Critical current measurements of high-temperature superconducting short samples at a wide range of temperatures and magnetic fields

NASA Astrophysics Data System (ADS)

Ma, Hongjun; Liu, Huajun; Liu, Fang; Zhang, Huahui; Ci, Lu; Shi, Yi; Lei, Lei

2018-01-01

High-Temperature Superconductors (HTS) are potential materials for high-field magnets, low-loss transmission cables, and Superconducting Magnetic Energy Storage (SMES) due to their high upper critical magnetic field (Hc2) and critical temperature (Tc). The critical current (Ic) of HTS, which is one of the most important parameters for superconductor application, depends strongly on the magnetic fields and temperatures. A new Ic measurement system that can carry out accurate Ic measurement for HTS short samples with various temperatures (4.2-80 K), magnetic fields (0-14 T), and angles of the magnetic field (0°-90°) has been developed. The Ic measurement system mainly consists of a measurement holder, temperature-control system, background magnet, test cryostat, data acquisition system, and DC power supply. The accuracy of temperature control is better than ±0.1 K over the 20-80 K range and ±0.05 K when measured below 20 K. The maximum current is over 1000 A with a measurement uncertainty of 1%. The system had been successfully used for YBa2Cu3O7-x(YBCO) tapes Ic determination with different temperatures and magnetic fields.

Long life of a short film.

PubMed

Wadia, R V

2000-01-01

What follows is an account of my personal experiences as an independent Indian film director who had the fortune to make the country's first openly gay film, the short BOMgAY That said, I would like this essay to be accepted as, rather than a critical appraisal of Indian cinema, a humbly autobiographical account of one individual caught in the hectic throes of political (and cinematic) visibility.

Gone before You Know It: Urban School Reform and the Short Life of the Education Action Zone Initiative

ERIC Educational Resources Information Center

Franklin, Barry M.

2005-01-01

This essay explores the fluctuations in and short-lived nature of urban school reform through a study of the Education Action Zone (EAZ) programme of Britain's New Labour government. Using the notion of civic capacity as a theoretical framework, the essay looks at this reform from the perspectives of its government proponents, critics outside of…

A new short-term forecasting model for the total electron content storm time disturbances

NASA Astrophysics Data System (ADS)

Tsagouri, Ioanna; Koutroumbas, Konstantinos; Elias, Panagiotis

2018-06-01

This paper aims to introduce a new model for the short-term forecast of the vertical Total Electron Content (vTEC). The basic idea of the proposed model lies on the concept of the Solar Wind driven autoregressive model for Ionospheric short-term Forecast (SWIF). In its original version, the model is operationally implemented in the DIAS system (http://dias.space.noa.gr) and provides alerts and warnings for upcoming ionospheric disturbances, as well as single site and regional forecasts of the foF2 critical frequency over Europe up to 24 h in advance. The forecasts are driven by the real time assessment of the solar wind conditions at ACE location. The comparative analysis of the variations in foF2 and vTEC during eleven geomagnetic storm events that occurred in the present solar cycle 24 reveals similarities but also differences in the storm-time response of the two characteristics with respect to the local time and the latitude of the observation point. Since the aforementioned dependences drive the storm-time forecasts of the SWIF model, the results obtained here support the upgrade of the SWIF's modeling technique in forecasting the storm-time vTEC variation from its onset to full development and recovery. According to the proposed approach, the vTEC storm-time response can be forecasted from 1 to 12-13 h before its onset, depending on the local time of the observation point at storm onset at L1. Preliminary results on the assessment of the performance of the proposed model and further considerations on its potential implementation in operational mode are also discussed.

Length-scale and strain rate-dependent mechanism of defect formation and fracture in carbon nanotubes under tensile loading

NASA Astrophysics Data System (ADS)

Javvaji, Brahmanandam; Raha, S.; Mahapatra, D. Roy

2017-02-01

Electromagnetic and thermo-mechanical forces play a major role in nanotube-based materials and devices. Under high-energy electron transport or high current densities, carbon nanotubes fail via sequential fracture. The failure sequence is governed by certain length scale and flow of current. We report a unified phenomenological model derived from molecular dynamic simulation data, which successfully captures the important physics of the complex failure process. Length-scale and strain rate-dependent defect nucleation, growth, and fracture in single-walled carbon nanotubes with diameters in the range of 0.47 to 2.03 nm and length which is about 6.17 to 26.45 nm are simulated. Nanotubes with long length and small diameter show brittle fracture, while those with short length and large diameter show transition from ductile to brittle fracture. In short nanotubes with small diameters, we observe several structural transitions like Stone-Wales defect initiation, its propagation to larger void nucleation, formation of multiple chains of atoms, conversion to monatomic chain of atoms, and finally complete fracture of the carbon nanotube. Hybridization state of carbon-carbon bonds near the end cap evolves, leading to the formation of monatomic chain in short nanotubes with small diameter. Transition from ductile to brittle fracture is also observed when strain rate exceeds a critical value. A generalized analytical model of failure is established, which correlates the defect energy during the formation of atomic chain with aspect ratio of the nanotube and strain rate. Variation in the mechanical properties such as elastic modulus, tensile strength, and fracture strain with the size and strain rate shows important implications in mitigating force fields and ways to enhance the life of electronic devices and nanomaterial conversion via fracture in manufacturing.

Vestibular short-latency evoked potential abolished by low-frequency noise exposure in rats.

PubMed

Stewart, Courtney E; Kanicki, Ariane C; Altschuler, Richard A; King, W M

2018-02-01

The vestibular system plays a critical role in detection of head movements and is essential for normal postural control. Because of their anatomical proximity to the cochlea, the otolith organs are selectively exposed to sound pressure and are at risk for noise overstimulation. Clinical reports suggest a link between noise exposure and balance problems, but the structural and physiological basis for this linkage is not well understood. The goal of this study was to determine the effects of low-frequency noise (LFN) on the otolith organs by correlating changes in vestibular short-latency evoked potentials (VsEPs) with changes in saccular afferent endings following noise exposure. LFN exposure transiently abolished the VsEP and reduced the number of stained calyces within the sacculus. Although some recovery of the VsEP waveform could be observed within 3 days after noise, at 3 wk recovery was only partial in most animals, consistent with a reduced number of afferents with calyceal endings. These data show that a single intense noise exposure is capable of causing a vestibular deficit that appears to mirror the synaptic deficit associated with hidden hearing loss after noise-induced cochlear injury. NEW & NOTEWORTHY This is the first study to explore the effects of low-frequency high-intensity noise on vestibular short-latency evoked potential (VsEP) responses, which shows a linkage between attenuated noise-induced VsEPs and pathological changes to otolith organ afferents. This finding suggests a potential limitation of the VsEP for evaluation of vestibular dysfunction, since the VsEP measurement may assess the activity of a specific class rather than all afferents.

Chemical constraints on the contribution of population III stars to cosmic reionization

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

Kulkarni, Girish; Hennawi, Joseph F.; Rollinde, Emmanuel

2014-05-20

Recent studies have highlighted that galaxies at z = 6-8 fall short of producing enough ionizing photons to reionize the intergalactic medium, and suggest that Population III stars could resolve this tension, because their harder spectra can produce ∼10 × more ionizing photons than Population II. We use a semi-analytic model of galaxy formation, which tracks galactic chemical evolution, to gauge the impact of Population III stars on reionization. Population III supernovae produce distinct metal abundances, and we argue that the duration of the Population III era can be constrained by precise relative abundance measurements in high-z damped Lyα absorbersmore » (DLAs), which provide a chemical record of past star formation. We find that a single generation of Population III stars can self-enrich galaxies above the critical metallicity Z {sub crit} = 10{sup –4} Z {sub ☉} for the Population III-to-II transition, on a very short timescale t {sub self-enrich} ∼ 10{sup 6} yr, owing to the large metal yields and short lifetimes of Population III stars. This subsequently terminates the Population III era, so they contribute ≳ 50% of the ionizing photons only for z ≳ 30, and at z = 10 contribute <1%. The Population III contribution can be increased by delaying metal mixing into the interstellar medium. However, comparing the resulting metal abundance pattern to existing measurements in z ≲ 6 DLAs, we show that the observed [O/Si] ratios of absorbers rule out Population III stars being a major contributor to reionization. Future abundance measurements of z ∼ 7-8 QSOs and gamma-ray bursts should probe the era when the chemical vestiges of Population III star formation become detectable.« less

Public-private differences in short-term neonatal outcomes following birth by prelabour caesarean section at early and full term.

PubMed

Adams, Nicole; Gibbons, Kristen S; Tudehope, David

2017-04-01

Prelabour caesarean section (CS) at early term (37 0 -38 6  weeks) is associated with higher rates of adverse short-term neonatal outcomes and higher costs than those performed at full term (39 0 -40 6  weeks). Prelabour CS is more common in private than in public hospitals in Australia, particularly at early term. To evaluate the impact of hospital sector (public or private) and timing of delivery on short-term neonatal outcomes following prelabour CS at term. A retrospective cohort study of 22 954 viable singleton prelabour CS births at term (37 0 -40 6  weeks) at a single centre encompassing co-located public and private hospitals during 1998-2013 was undertaken. Propensity score analysis was used to adjust for confounding differences between sectors. The primary outcome was Neonatal Critical Care Unit (NCCU) admission with serious morbidity. Secondary outcomes included respiratory distress, vigorous resuscitation and jaundice. The private hospital performed prelabour CS at over double the rate of the public hospital (33.7% of all private births vs 14.7% public) and more private than public prelabour CSs occurred at early term (66.8% vs 47.9%). Public babies were more than twice as likely as private babies to require admission to NCCU with serious morbidity (adjusted odds ratio (AOR) 2.54, 95% CI 1.77-3.65) but were less likely to need vigorous resuscitation (AOR 0.53, 95% CI 0.45-0.62). Disparities in outcomes between public and private cohorts were accentuated at full term. Despite early-term prelabour CSs occurring more often in the private hospital, public babies had more adverse outcomes and treatment escalations. © 2017 The Royal Australian and New Zealand College of Obstetricians and Gynaecologists.

Auxiliary-fermion approach to critical fluctuations in the two-dimensional quantum antiferromagnetic Heisenberg model

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

Brinckmann, Jan; Woelfle, Peter

2004-11-01

The nearest-neighbor quantum antiferromagnetic (AF) Heisenberg model for spin-1/2 on a two-dimensional square lattice is studied in the auxiliary-fermion representation. Expressing spin operators by canonical fermionic particles requires a constraint on the fermion charge Q{sub i}=1 on each lattice site i, which is imposed approximately through the thermal average. The resulting interacting fermion system is first treated in mean-field theory (MFT), which yields an AF ordered ground state and spin waves in quantitative agreement with conventional spin-wave theory. At finite temperature a self-consistent approximation beyond mean field is required in order to fulfill the Mermin-Wagner theorem. We first discuss amore » fully self-consistent approximation, where fermions are renormalized due to fluctuations of their spin density, in close analogy to FLEX. While static properties like the correlation length, {xi}(T){proportional_to}exp(aJ/T), come out correctly, the dynamical response lacks the magnon-like peaks which would reflect the appearance of short-range order at low T. This drawback, which is caused by overdamping, is overcome in a 'minimal self-consistent approximation' (MSCA), which we derive from the equations of motion. The MSCA features dynamical scaling at small energy and temperature and is qualitatively correct both in the regime of order-parameter relaxation at long wavelengths {lambda}>{xi} and in the short-range-order regime at {lambda}<{xi}. We also discuss the impact of vertex corrections and the problem of pseudo-gap formation in the single-particle density of states due to long-range fluctuations. Finally we show that the (short-range) magnetic order in MFT and MSCA helps to fulfill the constraint on the local fermion occupancy.« less

Controls for multi-scale temporal variation in methane flux of a subtropical tidal salt marsh

NASA Astrophysics Data System (ADS)

Li, H.

2016-12-01

Coastal wetlands provide critical carbon sequestration benefits, yet the production of methane (CH4) from these ecosystems can vary by an order of magnitude based on environmental and biological factors. Eddy covariance (EC) measurements for methane flux (FCH4) were performed in a subtropical tidal salt marsh of eastern China over 20 months. Spectral analysis techniques including the continuous wavelet transform, the wavelet coherence, the partial wavelet coherence and the multiple wavelet coherence were employed to analyze the periodicities and the main regulating factors of FCH4 in the tidal salt marsh. The annual budget of methane was 17.8 g C-CH4 m-2 yr-1, which was relatively high compared to those of most reported from inland wetland sites. In non-growing season, release of ebullition was the dominant driving mechanism for variability of FCH4 from hourly to monthly scales. There was no single dominant factor at short-term scale (half-day to 1-day) in growing season. It is worthwhile to note that tide was one of the most important factors regulating FCH4 at short time scale (half-day to 1-day). In comparison, the contribution of temperature to FCH4 at a short time scale (half-day to 1-day) was small due to its narrow range. In addition, plant-modulated transport and gross primary production also contributed to FCH4 at multiple temporal scales in this densely vegetated marsh, especially at weekly to monthly scales. Due to the complex interactive influences of tidal dynamics, temperature fluctuation, plant productivity, plant-mediated transport and release of ebullition on FCH4 exhibited no clear pattern of diurnal variation, but instead was highly variable.

Saccharomyces cerevisiae as a Model to Study Replicative Senescence Triggered by Telomere Shortening

PubMed Central

Teixeira, M. Teresa

2013-01-01

In many somatic human tissues, telomeres shorten progressively because of the DNA-end replication problem. Consequently, cells cease to proliferate and are maintained in a metabolically viable state called replicative senescence. These cells are characterized by an activation of DNA damage checkpoints stemming from eroded telomeres, which are bypassed in many cancer cells. Hence, replicative senescence has been considered one of the most potent tumor suppressor pathways. However, the mechanism through which short telomeres trigger this cellular response is far from being understood. When telomerase is removed experimentally in Saccharomyces cerevisiae, telomere shortening also results in a gradual arrest of population growth, suggesting that replicative senescence also occurs in this unicellular eukaryote. In this review, we present the key steps that have contributed to the understanding of the mechanisms underlying the establishment of replicative senescence in budding yeast. As in mammals, signals stemming from short telomeres activate the DNA damage checkpoints, suggesting that the early cellular response to the shortest telomere(s) is conserved in evolution. Yet closer analysis reveals a complex picture in which the apparent single checkpoint response may result from a variety of telomeric alterations expressed in the absence of telomerase. Accordingly, the DNA replication of eroding telomeres appears as a critical challenge for senescing budding yeast cells and the easy manipulation of S. cerevisiae is providing insights into the way short telomeres are integrated into their chromatin and nuclear environments. Finally, the loss of telomerase in budding yeast triggers a more general metabolic alteration that remains largely unexplored. Thus, telomerase-deficient S. cerevisiae cells may have more common points than anticipated with somatic cells, in which telomerase depletion is naturally programed, thus potentially inspiring investigations in mammalian cells. PMID:23638436

Resolving the Complexity of Human Skin Metagenomes Using Single-Molecule Sequencing

PubMed Central

Tsai, Yu-Chih; Deming, Clayton; Segre, Julia A.; Kong, Heidi H.; Korlach, Jonas

2016-01-01

ABSTRACT Deep metagenomic shotgun sequencing has emerged as a powerful tool to interrogate composition and function of complex microbial communities. Computational approaches to assemble genome fragments have been demonstrated to be an effective tool for de novo reconstruction of genomes from these communities. However, the resultant “genomes” are typically fragmented and incomplete due to the limited ability of short-read sequence data to assemble complex or low-coverage regions. Here, we use single-molecule, real-time (SMRT) sequencing to reconstruct a high-quality, closed genome of a previously uncharacterized Corynebacterium simulans and its companion bacteriophage from a skin metagenomic sample. Considerable improvement in assembly quality occurs in hybrid approaches incorporating short-read data, with even relatively small amounts of long-read data being sufficient to improve metagenome reconstruction. Using short-read data to evaluate strain variation of this C. simulans in its skin community at single-nucleotide resolution, we observed a dominant C. simulans strain with moderate allelic heterozygosity throughout the population. We demonstrate the utility of SMRT sequencing and hybrid approaches in metagenome quantitation, reconstruction, and annotation. PMID:26861018

Magnetic properties of tapiolite (FeTa2O6); a quasi two-dimensional (2D) antiferromagnet

NASA Astrophysics Data System (ADS)

Chung, E. M. L.; Lees, M. R.; McIntyre, G. J.; Wilkinson, C.; Balakrishnan, G.; Hague, J. P.; Visser, D.; McK Paul, D.

2004-11-01

The possibilities of two-dimensional (2D) short-range magnetic correlations and frustration effects in the mineral tapiolite are investigated using bulk-property measurements and neutron Laue diffraction. In this study of the magnetic properties of synthetic single-crystals of tapiolite, we find that single crystals of FeTa2O6 order antiferromagnetically at TN = 7.95 ± 0.05 K, with extensive two-dimensional correlations existing up to at least 40 K. Although we find no evidence that FeTa2O6 is magnetically frustrated, hallmarks of two-dimensional magnetism observed in our single-crystal data include: (i) broadening of the susceptibility maximum due to short-range correlations, (ii) a spin-flop transition and (iii) lambda anomalies in the heat capacity and d(χT)/dT. Complementary neutron Laue diffraction measurements reveal 1D magnetic diffuse scattering extending along the c* direction perpendicular to the magnetic planes. This magnetic diffuse scattering, observed for the first time using the neutron Laue technique by VIVALDI, arises directly as a result of 2D short-range spin correlations.

A critical pathway for patients with acute chest pain and low risk for short-term adverse cardiac events: role of outpatient stress testing.

PubMed

Meyer, Mary C; Mooney, Robert P; Sekera, Anna K

2006-05-01

We evaluate the safety and feasibility of a critical care pathway protocol in which patients with acute chest pain who are low risk for coronary artery disease and short-term adverse cardiac outcomes receive outpatient stress testing within 72 hours of an emergency department (ED) visit. We performed an observational study of an ED-based chest pain critical pathway in an urban, community hospital in 979 consecutive patients. Patients enrolled in the protocol were observed in the ED before receiving 72-hour outpatient stress testing. The pathway was primarily analyzed for rates of death or myocardial infarction in the 6 months after ED discharge and outpatient stress testing. Secondary outcome measures included need for coronary intervention at initial stress testing and within 6 months after discharge, subsequent ED visits for chest pain, and subsequent hospitalization. Of 871 stress-tested patients aged 40 years or older, who had low risk for coronary artery disease and short-term adverse cardiac events, and had 6-month follow-up, 18 (2%) required coronary intervention, 1 (0.1%) had a myocardial infarction within 1 month, 2 (0.2%) had a myocardial infarction within 6 months, 6 (0.7%) had normal stress test results after discharge but required cardiac catheterization within 6 months, and 5 (0.6%) returned to the ED within 6 months for ongoing chest pain. Hospital admission rates decreased significantly from 31.2% to 26.1% after initiation of the protocol (P<.001). For patients with chest pain and low risk for short-term cardiac events, outpatient stress testing is feasible, safe, and associated with decreased hospital admission rates. With an evidence-based protocol, physicians efficiently identify patients at low risk for clinically significant coronary artery disease and short-term adverse cardiac outcomes.

Self-organized criticality in single-neuron excitability

NASA Astrophysics Data System (ADS)

Gal, Asaf; Marom, Shimon

2013-12-01

We present experimental and theoretical arguments, at the single-neuron level, suggesting that neuronal response fluctuations reflect a process that positions the neuron near a transition point that separates excitable and unexcitable phases. This view is supported by the dynamical properties of the system as observed in experiments on isolated cultured cortical neurons, as well as by a theoretical mapping between the constructs of self-organized criticality and membrane excitability biophysics.

European Economic and Monetary Union: Why Should We Care?

DTIC Science & Technology

1992-04-15

economic, if not political unification, that calls for a single market, a central european bank and a single currency. Why, in one short decade, did the EC...directives to eliminate fiscal and technical barriers to trade, services, banking , insurance, transportation, and securities transactions. The Single...implications. A logical outgrowth of this is the establishment of a single european currency and a central bank to issue this currency. These are 12

Effects of noise and task loading on a communication task loading on a communication task

NASA Astrophysics Data System (ADS)

Orrell, Dean H., II

Previous research had shown the effect of noise on a single communication task. This research has been criticized as not being representative of a real world situation since subjects allocated all of their attention to only one task. In the present study, the effect of adding a loading task to a standard noise-communication paradigm was investigated. Subjects performed both a communication task (Modified Rhyme Test; House et al. 1965) and a short term memory task (Sternberg, 1969) in simulated levels of aircraft noise (95, 105 and 115 dB overall sound pressure level (OASPL)). Task loading was varied with Sternberg's task by requiring subjects to memorize one, four, or six alphanumeric characters. Simulated aircraft noise was varied between levels of 95, 105 and 115 dB OASPL using a pink noise source. Results show that the addition of Sternberg's task and little effect on the intelligibility of the communication task while response time for the communication task increased.

Personalizing gene therapy in gastric cancer.

PubMed

Vogiatzi, P; Cassone, M; Claudio, P P

2006-11-01

Gene therapy was proposed many decades ago as a more straightforward and definitive way of curing human diseases, but only recently technical advancements and improved knowledge have allowed its active development as a broad and promising research field. After the first successes in the cure of genetic and infectious diseases, it has been actively investigated as a means to decrease the burden and suffering generated by cancer. The field of gastric cancer is witnessing an impressive flourishing of studies testing the possibilities and actual efficacy of the many different strategies employed in gene therapy, and overall results seem to be two-sided: while original ideas and innovative protocols are providing extremely interesting contributions with great potential, more advanced-phase studies concluded so far have fallen short of expectations regarding efficacy, although invariably demonstrating little or no toxicity. An overview of the major efforts in this field is provided here, and a critical discussion is presented on the single strategies undertaken and on the overall balance between potentiality and pitfalls. Copyright 2006 Prous Science. All rights reserved.

Rolling epidemic of Legionnaires' disease outbreaks in small geographic areas.

PubMed

MacIntyre, C Raina; Dyda, Amalie; Bui, Chau Minh; Chughtai, Abrar Ahmad

2018-03-21

Legionnaires' disease (LD) is reported from many parts of the world, mostly linked to drinking water sources or cooling towers. We reviewed two unusual rolling outbreaks in Sydney and New York, each clustered in time and space. Data on these outbreaks were collected from public sources and compared to previous outbreaks in Australia and the US. While recurrent outbreaks of LD over time linked to an identified single source have been described, multiple unrelated outbreaks clustered in time and geography have not been previously described. We describe unusual geographic and temporal clustering of Legionella outbreaks in two cities, each of which experienced multiple different outbreaks within a small geographic area and within a short timeframe. The explanation for this temporal and spatial clustering of LD outbreaks in two cities is not clear, but climate variation and deteriorating water sanitation are two possible explanations. There is a need to critically analyse LD outbreaks and better understand changing trends to effectively prevent disease.

Shock compression of [001] single crystal silicon

DOE PAGES

Zhao, S.; Remington, B.; Hahn, E. N.; ...

2016-03-14

Silicon is ubiquitous in our advanced technological society, yet our current understanding of change to its mechanical response at extreme pressures and strain-rates is far from complete. This is due to its brittleness, making recovery experiments difficult. High-power, short-duration, laser-driven, shock compression and recovery experiments on [001] silicon (using impedance-matched momentum traps) unveiled remarkable structural changes observed by transmission electron microscopy. As laser energy increases, corresponding to an increase in peak shock pressure, the following plastic responses are are observed: surface cleavage along {111} planes, dislocations and stacking faults; bands of amorphized material initially forming on crystallographic orientations consistent withmore » dislocation slip; and coarse regions of amorphized material. Molecular dynamics simulations approach equivalent length and time scales to laser experiments and reveal the evolution of shock-induced partial dislocations and their crucial role in the preliminary stages of amorphization. Furthermore, application of coupled hydrostatic and shear stresses produce amorphization below the hydrostatically determined critical melting pressure under dynamic shock compression.« less

Analysis of Influenza and RSV dynamics in the community using a ‘Local Transmission Zone’ approach

NASA Astrophysics Data System (ADS)

Almogy, Gal; Stone, Lewi; Bernevig, B. Andrei; Wolf, Dana G.; Dorozko, Marina; Moses, Allon E.; Nir-Paz, Ran

2017-02-01

Understanding the dynamics of pathogen spread within urban areas is critical for the effective prevention and containment of communicable diseases. At these relatively small geographic scales, short-distance interactions and tightly knit sub-networks dominate the dynamics of pathogen transmission; yet, the effective boundaries of these micro-scale groups are generally not known and often ignored. Using clinical test results from hospital admitted patients we analyze the spatio-temporal distribution of Influenza Like Illness (ILI) in the city of Jerusalem over a period of three winter seasons. We demonstrate that this urban area is not a single, perfectly mixed ecology, but is in fact comprised of a set of more basic, relatively independent pathogen transmission units, which we term here Local Transmission Zones, LTZs. By identifying these LTZs, and using the dynamic pathogen-content information contained within them, we are able to differentiate between disease-causes at the individual patient level often with near-perfect predictive accuracy.

Ultrafast magnetization switching by spin-orbit torques

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

Garello, Kevin, E-mail: kevin.garello@mat.ethz.ch; Avci, Can Onur; Baumgartner, Manuel

2014-11-24

Spin-orbit torques induced by spin Hall and interfacial effects in heavy metal/ferromagnetic bilayers allow for a switching geometry based on in-plane current injection. Using this geometry, we demonstrate deterministic magnetization reversal by current pulses ranging from 180 ps to ms in Pt/Co/AlO{sub x} dots with lateral dimensions of 90 nm. We characterize the switching probability and critical current I{sub c} as a function of pulse length, amplitude, and external field. Our data evidence two distinct regimes: a short-time intrinsic regime, where I{sub c} scales linearly with the inverse of the pulse length, and a long-time thermally assisted regime, where I{sub c} variesmore » weakly. Both regimes are consistent with magnetization reversal proceeding by nucleation and fast propagation of domains. We find that I{sub c} is a factor 3–4 smaller compared to a single domain model and that the incubation time is negligibly small, which is a hallmark feature of spin-orbit torques.« less

Moderate UV Exposure Enhances Learning and Memory by Promoting a Novel Glutamate Biosynthetic Pathway in the Brain.

PubMed

Zhu, Hongying; Wang, Ning; Yao, Lei; Chen, Qi; Zhang, Ran; Qian, Junchao; Hou, Yiwen; Guo, Weiwei; Fan, Sijia; Liu, Siling; Zhao, Qiaoyun; Du, Feng; Zuo, Xin; Guo, Yujun; Xu, Yan; Li, Jiali; Xue, Tian; Zhong, Kai; Song, Xiaoyuan; Huang, Guangming; Xiong, Wei

2018-06-14

Sunlight exposure is known to affect mood, learning, and cognition. However, the molecular and cellular mechanisms remain elusive. Here, we show that moderate UV exposure elevated blood urocanic acid (UCA), which then crossed the blood-brain barrier. Single-cell mass spectrometry and isotopic labeling revealed a novel intra-neuronal metabolic pathway converting UCA to glutamate (GLU) after UV exposure. This UV-triggered GLU synthesis promoted its packaging into synaptic vesicles and its release at glutamatergic terminals in the motor cortex and hippocampus. Related behaviors, like rotarod learning and object recognition memory, were enhanced after UV exposure. All UV-induced metabolic, electrophysiological, and behavioral effects could be reproduced by the intravenous injection of UCA and diminished by the application of inhibitor or short hairpin RNA (shRNA) against urocanase, an enzyme critical for the conversion of UCA to GLU. These findings reveal a new GLU biosynthetic pathway, which could contribute to some of the sunlight-induced neurobehavioral changes. Copyright © 2018 Elsevier Inc. All rights reserved.

Shock compression of [001] single crystal silicon

NASA Astrophysics Data System (ADS)

Zhao, S.; Hahn, E. N.; Kad, B.; Remington, B. A.; Bringa, E. M.; Meyers, M. A.

2016-05-01

Silicon is ubiquitous in our advanced technological society, yet our current understanding of change to its mechanical response at extreme pressures and strain-rates is far from complete. This is due to its brittleness, making recovery experiments difficult. High-power, short-duration, laser-driven, shock compression and recovery experiments on [001] silicon (using impedance-matched momentum traps) unveiled remarkable structural changes observed by transmission electron microscopy. As laser energy increases, corresponding to an increase in peak shock pressure, the following plastic responses are are observed: surface cleavage along {111} planes, dislocations and stacking faults; bands of amorphized material initially forming on crystallographic orientations consistent with dislocation slip; and coarse regions of amorphized material. Molecular dynamics simulations approach equivalent length and time scales to laser experiments and reveal the evolution of shock-induced partial dislocations and their crucial role in the preliminary stages of amorphization. Application of coupled hydrostatic and shear stresses produce amorphization below the hydrostatically determined critical melting pressure under dynamic shock compression.

[Paradigm shift in the management of metastatic epidural spinal cord compression: the importance of preserving ambulation].

PubMed

Itshayek, Eyal

2013-12-01

In 2005, a Landmark study showed that direct decompressive surgery, followed by postoperative external beam radiotherapy (EBRT) is superior to EBRT alone in patients with metastatic epidural spinal cord compression (MESCC). Patients undergoing both surgery and EBRT had similar median survival but experienced longer ambulation than with EBRT alone. Additional studies have shown improvements in quality-of-life, higher cost-effectiveness, improved pain control, and higher functional status with surgery plus EBRT. Improved neurological outcome also improved the patients' ability to undergo postoperative adjuvant therapy. According to our experience, even patients over 65 or patients with aggressive primary tumors and additional metastases have benefited from surgical intervention, living longer than expected with preservation of ambulation and sphincter control until death or shortly before. Preserving ambulation is critical. With current surgical devices and techniques, patients with MESCC who present with a single area of cord compression, back pain, neurological deficit, or progressive deformity, may benefit from surgery prior to adjuvant radiation-based treatment or chemotherapy.

A dual-scale metal nanowire network transparent conductor for highly efficient and flexible organic light emitting diodes.

PubMed

Lee, Jinhwan; An, Kunsik; Won, Phillip; Ka, Yoonseok; Hwang, Hyejin; Moon, Hyunjin; Kwon, Yongwon; Hong, Sukjoon; Kim, Changsoon; Lee, Changhee; Ko, Seung Hwan

2017-02-02

Although solution processed metal nanowire (NW) percolation networks are a strong candidate to replace commercial indium tin oxide, their performance is limited in thin film device applications due to reduced effective electrical areas arising from the dimple structure and percolative voids that single size metal NW percolation networks inevitably possess. Here, we present a transparent electrode based on a dual-scale silver nanowire (AgNW) percolation network embedded in a flexible substrate to demonstrate a significant enhancement in the effective electrical area by filling the large percolative voids present in a long/thick AgNW network with short/thin AgNWs. As a proof of concept, the performance enhancement of a flexible phosphorescent OLED is demonstrated with the dual-scale AgNW percolation network compared to the previous mono-scale AgNWs. Moreover, we report that mechanical and oxidative robustness, which are critical for flexible OLEDs, are greatly increased by embedding the dual-scale AgNW network in a resin layer.

Dimensional Effects on the Charge Density Waves in Ultrathin Films of TiSe 2

DOE PAGES

Chen, P.; Chan, Y. -H.; Wong, M. -H.; ...

2016-09-20

Charge density wave (CDW) formation in solids is a critical phenomenon involving the collective reorganization of the electrons and atoms in the system into a wave structure, and it is expected to be sensitive to the geometric constraint of the system at the nanoscale. Here, we study the CDW transition in TiSe 2, a quasi-two-dimensional layered material, to determine the effects of quantum confinement and changing dimensions in films ranging from a single layer to multilayers. Of key interest is the characteristic length scale for the transformation from a two-dimensional case to the three-dimensional limit. Angle-resolved photoemission (ARPES) measurements ofmore » films with thicknesses up to six layers reveal substantial variations in the energy structure of discrete quantum well states; however, the temperature-dependent band-gap renormalization converges at just three layers. The results indicate a layer-dependent mixture of two transition temperatures and a very-short-range CDW interaction within a three-dimensional framework.« less

Strong Einstein-Podolsky-Rosen entanglement from a single squeezed light source

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

Eberle, Tobias; Centre for Quantum Engineering and Space-Time Research - QUEST, Leibniz Universitaet Hannover, Welfengarten 1, D-30167 Hannover; Haendchen, Vitus

Einstein-Podolsky-Rosen (EPR) entanglement is a criterion that is more demanding than just certifying entanglement. We theoretically and experimentally analyze the low-resource generation of bipartite continuous-variable entanglement, as realized by mixing a squeezed mode with a vacuum mode at a balanced beam splitter, i.e., the generation of so-called vacuum-class entanglement. We find that in order to observe EPR entanglement the total optical loss must be smaller than 33.3 %. However, arbitrarily strong EPR entanglement is generally possible with this scheme. We realize continuous-wave squeezed light at 1550 nm with up to 9.9 dB of nonclassical noise reduction, which is the highestmore » value at a telecom wavelength so far. Using two phase-controlled balanced homodyne detectors we observe an EPR covariance product of 0.502{+-}0.006<1, where 1 is the critical value. We discuss the feasibility of strong Gaussian entanglement and its application for quantum key distribution in a short-distance fiber network.« less

Long-Lasting Sound-Evoked Afterdischarge in the Auditory Midbrain.

PubMed

Ono, Munenori; Bishop, Deborah C; Oliver, Douglas L

2016-02-12

Different forms of plasticity are known to play a critical role in the processing of information about sound. Here, we report a novel neural plastic response in the inferior colliculus, an auditory center in the midbrain of the auditory pathway. A vigorous, long-lasting sound-evoked afterdischarge (LSA) is seen in a subpopulation of both glutamatergic and GABAergic neurons in the central nucleus of the inferior colliculus of normal hearing mice. These neurons were identified with single unit recordings and optogenetics in vivo. The LSA can continue for up to several minutes after the offset of the sound. LSA is induced by long-lasting, or repetitive short-duration, innocuous sounds. Neurons with LSA showed less adaptation than the neurons without LSA. The mechanisms that cause this neural behavior are unknown but may be a function of intrinsic mechanisms or the microcircuitry of the inferior colliculus. Since LSA produces long-lasting firing in the absence of sound, it may be relevant to temporary or chronic tinnitus or to some other aftereffect of long-duration sound.

Clique of Functional Hubs Orchestrates Population Bursts in Developmentally Regulated Neural Networks

PubMed Central

Luccioli, Stefano; Ben-Jacob, Eshel; Barzilai, Ari; Bonifazi, Paolo; Torcini, Alessandro

2014-01-01

It has recently been discovered that single neuron stimulation can impact network dynamics in immature and adult neuronal circuits. Here we report a novel mechanism which can explain in neuronal circuits, at an early stage of development, the peculiar role played by a few specific neurons in promoting/arresting the population activity. For this purpose, we consider a standard neuronal network model, with short-term synaptic plasticity, whose population activity is characterized by bursting behavior. The addition of developmentally inspired constraints and correlations in the distribution of the neuronal connectivities and excitabilities leads to the emergence of functional hub neurons, whose stimulation/deletion is critical for the network activity. Functional hubs form a clique, where a precise sequential activation of the neurons is essential to ignite collective events without any need for a specific topological architecture. Unsupervised time-lagged firings of supra-threshold cells, in connection with coordinated entrainments of near-threshold neurons, are the key ingredients to orchestrate population activity. PMID:25255443

Exercise-induced muscle damage and running economy in humans.

PubMed

Assumpção, Cláudio de Oliveira; Lima, Leonardo Coelho Rabello; Oliveira, Felipe Bruno Dias; Greco, Camila Coelho; Denadai, Benedito Sérgio

2013-01-01

Running economy (RE), defined as the energy demand for a given velocity of submaximal running, has been identified as a critical factor of overall distance running performance. Plyometric and resistance trainings, performed during a relatively short period of time (~15-30 days), have been successfully used to improve RE in trained athletes. However, these exercise types, particularly when they are unaccustomed activities for the individuals, may cause delayed onset muscle soreness, swelling, and reduced muscle strength. Some studies have demonstrated that exercise-induced muscle damage has a negative impact on endurance running performance. Specifically, the muscular damage induced by an acute bout of downhill running has been shown to reduce RE during subsequent moderate and high-intensity exercise (>65% VO₂max). However, strength exercise (i.e., jumps, isoinertial and isokinetic eccentric exercises) seems to impair RE only for subsequent high-intensity exercise (~90% VO₂max). Finally, a single session of resistance exercise or downhill running (i.e., repeated bout effect) attenuates changes in indirect markers of muscle damage and blunts changes in RE.

Mental Health on the Go: Effects of a Gamified Attention Bias Modification Mobile Application in Trait Anxious Adults

PubMed Central

Dennis, Tracy A.; O’Toole, Laura

2015-01-01

Interest in the use of mobile technology to deliver mental health services has grown in light of the economic and practical barriers to treatment. Yet, research on alternative delivery strategies that are more affordable, accessible, and engaging is in its infancy. Attention bias modification training (ABMT), has potential to reduce treatment barriers as a mobile intervention for stress and anxiety, but the degree to which ABMT can be embedded in a mobile gaming format and its potential for transfer of benefits is unknown. The present study examined effects of a gamified ABMT mobile application in highly trait anxious participants (N = 78). A single session of the active compared to placebo training reduced subjective anxiety and observed stress reactivity. Critically, the long (45 minutes) but not short (25 minutes) active training condition reduced the core cognitive process implicated in ABMT (threat bias) as measured by an untrained, gold-standard protocol. PMID:26029490

Many-body delocalization with random vector potentials

NASA Astrophysics Data System (ADS)

Cheng, Chen; Mondaini, Rubem

In this talk we present the ergodic properties of excited states in a model of interacting fermions in quasi-one dimensional chains subjected to a random vector potential. In the non-interacting limit, we show that arbitrarily small values of this complex off-diagonal disorder triggers localization for the whole spectrum; the divergence of the localization length in the single particle basis is characterized by a critical exponent ν which depends on the energy density being investigated. However, when short-ranged interactions are included, the localization is lost and the system is ergodic regardless of the magnitude of disorder in finite chains. Our numerical results suggest a delocalization scheme for arbitrary small values of interactions. This finding indicates that the standard scenario of the many-body localization cannot be obtained in a model with random gauge fields. This research is financially supported by the National Natural Science Foundation of China (NSFC) (Grant Nos. U1530401 and 11674021). RM also acknowledges support from NSFC (Grant No. 11650110441).

The finite scaling for S = 1 XXZ chains with uniaxial single-ion-type anisotropy

NASA Astrophysics Data System (ADS)

Wang, Honglei; Xiong, Xingliang

2014-03-01

The scaling behavior of criticality for spin-1 XXZ chains with uniaxial single-ion-type anisotropy is investigated by employing the infinite matrix product state representation with the infinite time evolving block decimation method. At criticality, the accuracy of the ground state of a system is limited by the truncation dimension χ of the local Hilbert space. We present four evidences for the scaling of the entanglement entropy, the largest eigenvalue of the Schmidt decomposition, the correlation length, and the connection between the actual correlation length ξ and the energy. The result shows that the finite scalings are governed by the central charge of the critical system. Also, it demonstrates that the infinite time evolving block decimation algorithm by the infinite matrix product state representation can be a quite accurate method to simulate the critical properties at criticality.

Multiaxial Fatigue Life Prediction Based on Short Crack Propagation Model with Equivalent Strain Parameter

NASA Astrophysics Data System (ADS)

Zhao, Xiang-Feng; Shang, De-Guang; Sun, Yu-Juan; Song, Ming-Liang; Wang, Xiao-Wei

2018-01-01

The maximum shear strain and the normal strain excursion on the critical plane are regarded as the primary parameters of the crack driving force to establish a new short crack model in this paper. An equivalent strain-based intensity factor is proposed to correlate the short crack growth rate under multiaxial loading. According to the short crack model, a new method is proposed for multiaxial fatigue life prediction based on crack growth analysis. It is demonstrated that the method can be used under proportional and non-proportional loadings. The predicted results showed a good agreement with experimental lives in both high-cycle and low-cycle regions.

[Contribution of the study of singing in tune in musically non-expert subjects: importance of short term memory of the pitch (19 to 28 year-old subjects)].

PubMed

Belin, S; Peuvergne, A; Sarfati, J

2005-01-01

In the singing, which requires precise knowledge of the relevant musical code in use, accuracy of intonation plays a central role. Singing in tune requires to perceive pitch precisely and to memorize it before planning and executing the accurate vocal motion, which allows the exact emission of the correct pitch. Our work investigated the role of short term memory of pitch on singing accuracy. For that purpose, the experimental protocol of Deutsch (1970) was adapted for a perception and a production task. Participants were selected for their singing accuracy and separated into two groups of ten singing in tune and ten out-of-tune. All participants perceived pitch height exactly and were musically non-experts. For the perception and the production tasks, participants had to either compare or reproduce single pitches or two-pitch-sets. For the perception task, participants had to compare either single pitches or two-pitch patterns, all separated by a five seconds delay. For the production task, participants had to reproduce either single pitches or two-pitch patterns after a five seconds delay. The five seconds delay was either filled with intervening numbers, or with intervening tones, or without any disturbing sound. In perception and production task, the presence of intervening tones disturbs deeply the success of the subjects for every trial. Performance of the in-tune singing group is better for all the exercises while the other group had difficulties on single pitches and two-pitch patterns and was more disturbed by the effect of the intervening material. The outcome suggests that short term memory of pitch and accuracy of intonation would be closely linked. Further research needs to specify if that would mean that troubles in singing in tune are a consequence of a low-efficient short term memory of pitch, or if that troubles would hold up the right construction of the short term memory of pitch.

Short- and Long-Term Sleep Stability in Insomniacs and Healthy Controls.

PubMed

Gaines, Jordan; Vgontzas, Alexandros N; Fernandez-Mendoza, Julio; Basta, Maria; Pejovic, Slobodanka; He, Fan; Bixler, Edward O

2015-11-01

Assess the short- and long-term stability of sleep duration in patients with insomnia and normal-sleeping controls. Observational short-term and prospective studies. Sleep laboratory. Patients with insomnia (n = 150) and controls (n = 151) were recruited from the local community or sleep disorders clinic. A subsample of 95 men from the Penn State Adult Cohort (PSAC) were followed up 2.6 y after their initial visit. Participants underwent a physical examination and 8-h polysomnography (PSG) recording for 3 consecutive nights (controls and insomniacs), or 2 single nights separated by several years (PSAC). Intraclass correlation coefficients (ICCs) assessed the stability of the variables total sleep time (TST), sleep onset latency (SOL), and wake after sleep onset (WASO). We also examined persistence of the first-night classification of "short" versus "normal" sleep duration on subsequent nights. Stability of TST, SOL, and WASO based on 1 night were slight to moderate in both patients with insomnia (ICC = 0.37-0.57) and controls (ICC = 0.39-0.59), and became substantial to almost perfect when based on the average of 3 nights (ICC = 0.64-0.81). We observed similar degrees of stability for TST and WASO in the longitudinal sample, with moderate stability based on a single night and substantial stability based on both nights. In examining the persistence of "short" and "normal" sleep duration, 71.4% (controls), 74.7% (patients with insomnia), and 72.6% (longitudinal sample) of participants retained their first-night classifications over subsequent nights. Sleep duration variables, particularly total sleep time based on 3 consecutive nights in both patients with insomnia and controls or two single-night recordings separated by several years, are stable and reflect a person's habitual sleep. Furthermore, a single night in the laboratory may be useful for reliably classifying one's sleep duration. © 2015 Associated Professional Sleep Societies, LLC.

Motion stability of high-speed maglev systems in consideration of aerodynamic effects: a study of a single magnetic suspension system

NASA Astrophysics Data System (ADS)

Wu, Han; Zeng, Xiao-Hui; Yu, Yang

2017-12-01

In this study, the intrinsic mechanism of aerodynamic effects on the motion stability of a high-speed maglev system was investigated. The concept of a critical speed for maglev vehicles considering the aerodynamic effect is proposed. The study was carried out based on a single magnetic suspension system, which is convenient for proposing relevant concepts and obtaining explicit expressions. This study shows that the motion stability of the suspension system is closely related to the vehicle speed when aerodynamic effects are considered. With increases of the vehicle speed, the stability behavior of the system changes. At a certain vehicle speed, the stability of the system reaches a critical state, followed by instability. The speed corresponding to the critical state is the critical speed. Analysis reveals that when the system reaches the critical state, it takes two forms, with two critical speeds, and thus two expressions for the critical speed are obtained. The conditions of the existence of the critical speed were determined, and the effects of the control parameters and the lift coefficient on the critical speed were analyzed by numerical analysis. The results show that the first critical speed appears when the aerodynamic force is upward, and the second critical speed appears when the aerodynamic force is downward. Moreover, both critical speeds decrease with the increase of the lift coefficient.

Assessment and treatment of short-term and working memory impairments in stroke aphasia: a practical tutorial.

PubMed

Salis, Christos; Kelly, Helen; Code, Chris

2015-01-01

Aphasia following stroke refers to impairments that affect the comprehension and expression of spoken and/or written language, and co-occurring cognitive deficits are common. In this paper we focus on short-term and working memory impairments that impact on the ability to retain and manipulate auditory-verbal information. Evidence from diverse paradigms (large group studies, case studies) report close links between short-term/working memory and language functioning in aphasia. This evidence leads to the hypothesis that treating such memory impairments would improve language functioning. This link has only recently been acknowledged in aphasia treatment but has not been embraced widely by clinicians. To examine the association between language, and short-term and working memory impairments in aphasia. To describe practical ways of assessing short-term and working memory functioning that could be used in clinical practice. To discuss and critically appraise treatments of short-term and working memory reported in the literature. Taking a translational research approach, this paper provides clinicians with current evidence from the literature and practical information on how to assess and treat short-term and working memory impairments in people with aphasia. Published treatments of short-term and/or working memory in post-stroke aphasia are discussed through a narrative review. This paper provides the following. A theoretical rationale for adopting short-term and working memory treatments in aphasia. It highlights issues in differentially diagnosing between short-term, working memory disorders and other concomitant impairments, e.g. apraxia of speech. It describes short-term and working memory assessments with practical considerations for use with people with aphasia. It also offers a description of published treatments in terms of participants, treatments and outcomes. Finally, it critically appraises the current evidence base relating to the treatment of short-term and working memory treatments. The links between short-term/working memory functioning and language in aphasia are generally acknowledged. These strongly indicate the need to incorporate assessment of short-term/working memory functioning for people with aphasia. While the supportive evidence for treatment is growing and appears to highlight the benefits of including short-term/working memory in aphasia treatment, the quality of the evidence in its current state is poor. However, because of the clinical needs of people with aphasia and the prevalence of short-term/working memory impairments, incorporating related treatments through practice-based evidence is advocated. © 2015 Royal College of Speech and Language Therapists.

Effect of Forging Parameters on Low Cycle Fatigue Behaviour of Al/Basalt Short Fiber Metal Matrix Composites

PubMed Central

Karthigeyan, R.; Ranganath, G.

2013-01-01

This paper deals with metal matrix composites (MMCs) of Al 7075 alloy containing different weight percentage (2.5, 5, 7.5, and 10) basalt short fiber reinforcement and unreinforced matrix alloy. The samples were produced by the permanent stir casting technique. The casting ingots were cut into blanks to be forged in single stage and double stage, using MN press and graphite-based lubricant. The microstructures and fatigue properties of the matrix alloy and MMC samples were investigated in the as cast state and in the single and double stage forging operations. The microstructure results showed that the forged sample had a uniform distribution of the basalt short fiber throughout the specimens. Evaluation of the fatigue properties showed that the forged samples had higher values than those of the as cast counterparts. After forging, the enhancement of the fatigue strength of the matrix alloy was so significant and high in the case of 2.5 and 5.0 wt. percentage basalt short fiber reinforced MMC, and there was no enhancement in 7.5 and 10 weight percentages short fiber reinforced MMCs. The fracture damage was mainly due to decohesion at the matrix-fiber interface. PMID:24298207

Effect of forging parameters on low cycle fatigue behaviour of Al/basalt short fiber metal matrix composites.

PubMed

Karthigeyan, R; Ranganath, G

2013-01-01

This paper deals with metal matrix composites (MMCs) of Al 7075 alloy containing different weight percentage (2.5, 5, 7.5, and 10) basalt short fiber reinforcement and unreinforced matrix alloy. The samples were produced by the permanent stir casting technique. The casting ingots were cut into blanks to be forged in single stage and double stage, using MN press and graphite-based lubricant. The microstructures and fatigue properties of the matrix alloy and MMC samples were investigated in the as cast state and in the single and double stage forging operations. The microstructure results showed that the forged sample had a uniform distribution of the basalt short fiber throughout the specimens. Evaluation of the fatigue properties showed that the forged samples had higher values than those of the as cast counterparts. After forging, the enhancement of the fatigue strength of the matrix alloy was so significant and high in the case of 2.5 and 5.0 wt. percentage basalt short fiber reinforced MMC, and there was no enhancement in 7.5 and 10 weight percentages short fiber reinforced MMCs. The fracture damage was mainly due to decohesion at the matrix-fiber interface.

On the critical forcing amplitude of forced nonlinear oscillators

NASA Astrophysics Data System (ADS)

Febbo, Mariano; Ji, Jinchen C.

2013-12-01

The steady-state response of forced single degree-of-freedom weakly nonlinear oscillators under primary resonance conditions can exhibit saddle-node bifurcations, jump and hysteresis phenomena, if the amplitude of the excitation exceeds a certain value. This critical value of excitation amplitude or critical forcing amplitude plays an important role in determining the occurrence of saddle-node bifurcations in the frequency-response curve. This work develops an alternative method to determine the critical forcing amplitude for single degree-of-freedom nonlinear oscillators. Based on Lagrange multipliers approach, the proposed method considers the calculation of the critical forcing amplitude as an optimization problem with constraints that are imposed by the existence of locations of vertical tangency. In comparison with the Gröbner basis method, the proposed approach is more straightforward and thus easy to apply for finding the critical forcing amplitude both analytically and numerically. Three examples are given to confirm the validity of the theoretical predictions. The first two present the analytical form for the critical forcing amplitude and the third one is an example of a numerically computed solution.

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

Liu, Yu; Petrovic, C.

Some critical properties of the single-crystalline semiconducting ferromagnet Cr 2 Ge 2 Te 6 were investigated by bulk dc magnetization around the paramagnetic to ferromagnetic phase transition. Critical exponents β = 0.200 ± 0.003 with a critical temperature T c = 62.65 ± 0.07 K and γ = 1.28 ± 0.03 with T c = 62.75 ± 0.06 K are obtained by the Kouvel-Fisher method whereas δ = 7.96 ± 0.01 is obtained by a critical isotherm analysis at T c = 62.7 K. These critical exponents obey the Widom scaling relation δ = 1 + γ / β ,more » indicating self-consistency of the obtained values. Furthermore, with these critical exponents the isotherm M ( H ) curves below and above the critical temperatures collapse into two independent universal branches, obeying the single scaling equation m = f ± ( h ) , where m and h are renormalized magnetization and field, respectively. The determined exponents match well with those calculated from the results of the renormalization group approach for a two-dimensional Ising system coupled with a long-range interaction between spins decaying as J ( r ) ≈ r - ( d + σ ) with σ = 1.52 .« less

Short-term hydro generation and interchange contract scheduling for Swiss Rail

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

Christoforidis, M.; Awobamise, B.; Tong, S.

This paper describes the Short-Term Resource Scheduling (STRS) function that has been developed by Siemens-Empros as part of the new SBB/Direktion Kraftwerk (Swiss Rail) Energy Management System. Optimal scheduling of the single-phase hydro plants, single-phase and three-phase energy accounts, and purchase and sale of three phase energy subject to a multitude of physical and contractual constraints (including spinning and regulating reserve requirements), is the main objective of the STRS function. The operations planning horizon of STRS is one day to one week using an hourly time increment.

Identification of short single disulfide-containing contryphans from the venom of cone snails using de novo mass spectrometry-based sequencing methods.

PubMed

Franklin, Jayaseelan Benjamin; Rajesh, Rajaian Pushpabai; Vinithkumar, Nambali Valsalan; Kirubagaran, Ramalingam

2017-06-15

We identified 12 short single disulfide-containing conopeptides from the venom of Conus coronatus, C. leopardus, C. lividus and C. zonatus. Interestingly, we detected the shortest contryphan sequence thus far characterized which contains only six amino acid residues. We also identified three distinct contryphan sequences of C. lividus without any proline residues and one sequence with an unusual post-translational modification (bromination of tryptophan). Furthermore, we characterized venom peptides of C. zonatus for the first time. Copyright © 2017 Elsevier Ltd. All rights reserved.

A Critical Examination of Communication Textbooks

ERIC Educational Resources Information Center

Hanasono, Lisa K.

2018-01-01

Courses: This single-class teaching activity was designed for courses on critical communication pedagogy (CCP), gender and race, communication education, research methods, and visual communication. Objectives: By completing this activity, students should be able to (1) describe the principles of CCP, (2) examine critically how race and gender are…

Beyond Buzzword Bingo: a Critical Examination of Genre, Culture, and Communication

ERIC Educational Resources Information Center

Hanasono, Lisa K.

2017-01-01

Courses: This single-class teaching activity was designed for courses on public speaking, rhetorical criticism, and critical thinking. In addition, instructors can adapt this activity for online or face-to-face courses on intercultural communication, organizational communication, listening, and political communication. Objectives: By completing…

[Effects of slope gradient on slope runoff and sediment yield under different single rainfall conditions].

PubMed

He, Ji-Jun; Cai, Qiang-Guo; Liu, Song-Bo

2012-05-01

Based on the field observation data of runoff and sediment yield produced by single rainfall events in runoff plots, this paper analyzed the variation patterns of runoff and sediment yield on the slopes with different gradients under different single rainfall conditions. The differences in the rainfall conditions had little effects on the variation patterns of slope runoff with the gradient. Under the conditions of six different rainfall events in the study area, the variation patterns of slope runoff with the gradient were basically the same, i. e., the runoff increased with increasing gradient, but the increment of the runoff decreased slightly with increasing gradient, which was mainly determined by the infiltration flux of atmospheric precipitation. Rainfall condition played an important role on the slope sediment yield. Generally, there existed a critical slope gradient for slope erosion, but the critical gradient was not a fixed value, which varied with rainfall condition. The critical slope gradient for slope erosion increased with increasing slope gradient. When the critical slope gradient was greater, the variation of slope sediment yield with slope gradient always became larger.

A survey on investigating the need for intelligent power-aware load balanced routing protocols for handling critical links in MANETs.

PubMed

Sivakumar, B; Bhalaji, N; Sivakumar, D

2014-01-01

In mobile ad hoc networks connectivity is always an issue of concern. Due to dynamism in the behavior of mobile nodes, efficiency shall be achieved only with the assumption of good network infrastructure. Presence of critical links results in deterioration which should be detected in advance to retain the prevailing communication setup. This paper discusses a short survey on the specialized algorithms and protocols related to energy efficient load balancing for critical link detection in the recent literature. This paper also suggests a machine learning based hybrid power-aware approach for handling critical nodes via load balancing.

A Survey on Investigating the Need for Intelligent Power-Aware Load Balanced Routing Protocols for Handling Critical Links in MANETs

PubMed Central

Sivakumar, B.; Bhalaji, N.; Sivakumar, D.

2014-01-01

In mobile ad hoc networks connectivity is always an issue of concern. Due to dynamism in the behavior of mobile nodes, efficiency shall be achieved only with the assumption of good network infrastructure. Presence of critical links results in deterioration which should be detected in advance to retain the prevailing communication setup. This paper discusses a short survey on the specialized algorithms and protocols related to energy efficient load balancing for critical link detection in the recent literature. This paper also suggests a machine learning based hybrid power-aware approach for handling critical nodes via load balancing. PMID:24790546

Bone marrow fat quantification in the presence of trabecular bone: initial comparison between water-fat imaging and single-voxel MRS

PubMed Central

Karampinos, Dimitrios C.; Melkus, Gerd; Baum, Thomas; Bauer, Jan S.; Rummeny, Ernst J.; Krug, Roland

2013-01-01

Purpose The purpose of the present study was to test the relative performance of chemical shift-based water-fat imaging in measuring bone marrow fat fraction in the presence of trabecular bone, having as reference standard the single-voxel magnetic resonance spectroscopy (MRS). Methods Six-echo gradient echo imaging and single-voxel MRS measurements were performed on the proximal femur of seven healthy volunteers. The bone marrow fat spectrum was characterized based on the magnitude of measurable fat peaks and an a priori knowledge of the chemical structure of triglycerides, in order to accurately extract the water peak from the overlapping broad fat peaks in MRS. The imaging-based fat fraction results were then compared to the MRS-based results both without and with taking into consideration the presence of short T2* water components in MRS. Results There was a significant underestimation of the fat fraction using the MRS model not accounting for short T2* species with respect to the imaging-based water fraction. A good equivalency was observed between the fat fraction using the MRS model accounting for short T2* species and the imaging-based fat fraction (R2=0.87). Conclusion The consideration of the short T2* water species effect on bone marrow fat quantification is essential when comparing MRS-based and imaging-based fat fraction results. PMID:23657998

Perception of Affordance during Short-Term Exposure to Weightlessness in Parabolic Flight

PubMed Central

Bourrelly, Aurore; McIntyre, Joseph; Morio, Cédric; Despretz, Pascal; Luyat, Marion

2016-01-01

We investigated the role of the visual eye-height (VEH) in the perception of affordance during short-term exposure to weightlessness. Sixteen participants were tested during parabolic flight (0g) and on the ground (1g). Participants looked at a laptop showing a room in which a doorway-like aperture was presented. They were asked to adjust the opening of the virtual doorway until it was perceived to be just wide enough to pass through (i.e., the critical aperture). We manipulated VEH by raising the level of the floor in the visual room by 25 cm. The results showed effects of VEH and of gravity on the perceived critical aperture. When VEH was reduced (i.e., when the floor was raised), the critical aperture diminished, suggesting that widths relative to the body were perceived to be larger. The critical aperture was also lower in 0g, for a given VEH, suggesting that participants perceived apertures to be wider or themselves to be smaller in weightlessness, as compared to normal gravity. However, weightlessness also had an effect on the subjective level of the eyes projected into the visual scene. Thus, setting the critical aperture as a fixed percentage of the subjective visual eye-height remains a viable hypothesis to explain how human observers judge visual scenes in terms of potential for action or “affordances”. PMID:27097218

Critical behavior of quasi-two-dimensional semiconducting ferromagnet Cr 2 Ge 2 Te 6

DOE PAGES

Liu, Yu; Petrovic, C.

2017-08-03

Some critical properties of the single-crystalline semiconducting ferromagnet Cr 2 Ge 2 Te 6 were investigated by bulk dc magnetization around the paramagnetic to ferromagnetic phase transition. Critical exponents β = 0.200 ± 0.003 with a critical temperature T c = 62.65 ± 0.07 K and γ = 1.28 ± 0.03 with T c = 62.75 ± 0.06 K are obtained by the Kouvel-Fisher method whereas δ = 7.96 ± 0.01 is obtained by a critical isotherm analysis at T c = 62.7 K. These critical exponents obey the Widom scaling relation δ = 1 + γ / β ,more » indicating self-consistency of the obtained values. Furthermore, with these critical exponents the isotherm M ( H ) curves below and above the critical temperatures collapse into two independent universal branches, obeying the single scaling equation m = f ± ( h ) , where m and h are renormalized magnetization and field, respectively. The determined exponents match well with those calculated from the results of the renormalization group approach for a two-dimensional Ising system coupled with a long-range interaction between spins decaying as J ( r ) ≈ r - ( d + σ ) with σ = 1.52 .« less

Electromigration kinetics and critical current of Pb-free interconnects

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

Lu, Minhua; Rosenberg, Robert

2014-04-07

Electromigration kinetics of Pb-free solder bump interconnects have been studied using a single bump parameter sweep technique. By removing bump to bump variations in structure, texture, and composition, the single bump sweep technique has provided both activation energy and power exponents that reflect atomic migration and interface reactions with fewer samples, shorter stress time, and better statistics than standard failure testing procedures. Contact metallurgies based on Cu and Ni have been studied. Critical current, which corresponds to the Blech limit, was found to exist in the Ni metallurgy, but not in the Cu metallurgy. A temperature dependence of critical currentmore » was also observed.« less

Immature HIV-1 lattice assembly dynamics are regulated by scaffolding from nucleic acid and the plasma membrane

PubMed Central

Pak, Alexander J.; Grime, John M. A.; Sengupta, Prabuddha; Chen, Antony K.; Durumeric, Aleksander E. P.; Srivastava, Anand; Yeager, Mark; Briggs, John A. G.; Lippincott-Schwartz, Jennifer; Voth, Gregory A.

2017-01-01

The packaging and budding of Gag polyprotein and viral RNA is a critical step in the HIV-1 life cycle. High-resolution structures of the Gag polyprotein have revealed that the capsid (CA) and spacer peptide 1 (SP1) domains contain important interfaces for Gag self-assembly. However, the molecular details of the multimerization process, especially in the presence of RNA and the cell membrane, have remained unclear. In this work, we investigate the mechanisms that work in concert between the polyproteins, RNA, and membrane to promote immature lattice growth. We develop a coarse-grained (CG) computational model that is derived from subnanometer resolution structural data. Our simulations recapitulate contiguous and hexameric lattice assembly driven only by weak anisotropic attractions at the helical CA–SP1 junction. Importantly, analysis from CG and single-particle tracking photoactivated localization (spt-PALM) trajectories indicates that viral RNA and the membrane are critical constituents that actively promote Gag multimerization through scaffolding, while overexpression of short competitor RNA can suppress assembly. We also find that the CA amino-terminal domain imparts intrinsic curvature to the Gag lattice. As a consequence, immature lattice growth appears to be coupled to the dynamics of spontaneous membrane deformation. Our findings elucidate a simple network of interactions that regulate the early stages of HIV-1 assembly and budding. PMID:29114055

GSK3 is required for rapalogs to induce degradation of some oncogenic proteins and to suppress cancer cell growth.

PubMed

Koo, Junghui; Wang, Xuerong; Owonikoko, Taofeek K; Ramalingam, Suresh S; Khuri, Fadlo R; Sun, Shi-Yong

2015-04-20

The single-agent activity of rapalogs (rapamycin and its analogues) in most tumor types has been modest at best. The underlying mechanisms are largely unclear. In this report, we have uncovered a critical role of GSK3 in regulating degradation of some oncogenic proteins induced by rapalogs and cell sensitivity to rapalogs. The basal level of GSK3 activity was positively correlated with cell sensitivity of lung cancer cell lines to rapalogs. GSK3 inhibition antagonized rapamycin's growth inhibitory effects both in vitro and in vivo, while enforced activation of GSK3β sensitized cells to rapamycin. GSK3 inhibition rescued rapamcyin-induced reduction of several oncogenic proteins such as cyclin D1, Mcl-1 and c-Myc, without interfering with the ability of rapamycin to suppress mTORC1 signaling and cap binding. Interestingly, rapamycin induces proteasomal degradation of these oncogenic proteins, as evidenced by their decreased stabilities induced by rapamcyin and rescue of their reduction by proteasomal inhibition. Moreover, acute or short-time rapamycin treatment dissociated not only raptor, but also rictor from mTOR in several tested cell lines, suggesting inhibition of both mTORC1 and mTORC2. Thus, induction of GSK3-dependent degradation of these oncogenic proteins is likely secondary to mTORC2 inhibition; this effect should be critical for rapamycin to exert its anticancer activity.

GSK3 is required for rapalogs to induce degradation of some oncogenic proteins and to suppress cancer cell growth

PubMed Central

Koo, Junghui; Wang, Xuerong; Owonikoko, Taofeek K.; Ramalingam, Suresh S.; Khuri, Fadlo R.; Sun, Shi-Yong

2015-01-01

The single-agent activity of rapalogs (rapamycin and its analogues) in most tumor types has been modest at best. The underlying mechanisms are largely unclear. In this report, we have uncovered a critical role of GSK3 in regulating degradation of some oncogenic proteins induced by rapalogs and cell sensitivity to rapalogs. The basal level of GSK3 activity was positively correlated with cell sensitivity of lung cancer cell lines to rapalogs. GSK3 inhibition antagonized rapamycin's growth inhibitory effects both in vitro and in vivo, while enforced activation of GSK3β sensitized cells to rapamycin. GSK3 inhibition rescued rapamcyin-induced reduction of several oncogenic proteins such as cyclin D1, Mcl-1 and c-Myc, without interfering with the ability of rapamycin to suppress mTORC1 signaling and cap binding. Interestingly, rapamycin induces proteasomal degradation of these oncogenic proteins, as evidenced by their decreased stabilities induced by rapamcyin and rescue of their reduction by proteasomal inhibition. Moreover, acute or short-time rapamycin treatment dissociated not only raptor, but also rictor from mTOR in several tested cell lines, suggesting inhibition of both mTORC1 and mTORC2. Thus, induction of GSK3-dependent degradation of these oncogenic proteins is likely secondary to mTORC2 inhibition; this effect should be critical for rapamycin to exert its anticancer activity. PMID:25797247

Critical Behavior and Macroscopic Phase Diagram of the Monoaxial Chiral Helimagnet Cr 1/3NbS 2

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

Clements, Eleanor M.; Das, Raja; Li, Ling

2017-07-26

Cr 1/3NbS 2 is a unique example of a hexagonal chiral helimagnet with high crystalline anisotropy, and has generated growing interest for a possible magnetic field control of the incommensurate spin spiral. Here, we construct a comprehensive phase diagram based on detailed magnetization measurements of a high quality single crystal of Cr 1/3NbS 2 over three magnetic field regions. An analysis of the critical properties in the forced ferromagnetic region yields 3D Heisenberg exponents β = 0.3460 ± 0.040, γ = 1.344 ± 0.002, and T C = 130.78 K ± 0.044, which are consistent with the localized nature themore » of Cr 3+ moments and suggest short-range ferromagnetic interactions. We exploit the temperature and magnetic field dependence of magnetic entropy change (ΔS M) to accurately map the nonlinear crossover to the chiral soliton lattice regime from the chiral helimagnetic phase. Our observations in the low field region are consistent with the existence of chiral ordering in a temperature range above the Curie temperature, T C < T < T*, where a first-order transition has been previously predicted. An analysis of the universal behavior of ΔS M(T,H) experimentally demonstrates for the first time the first-order nature of the onset of chiral ordering.« less

Sulfur poisoning of Ni/Gadolinium-doped ceria anodes: A long-term study outlining stable solid oxide fuel cell operation

NASA Astrophysics Data System (ADS)

Riegraf, Matthias; Zekri, Atef; Knipper, Martin; Costa, Rémi; Schiller, Günter; Friedrich, K. Andreas

2018-03-01

This work presents an analysis of the long-term behavior of nickel/gadolinium-doped ceria (CGO) anode-based solid oxide fuel cells (SOFC) under sulfur poisoning conditions. A parameter study of sulfur-induced irreversible long-term degradation of commercial, high-performance single cells was carried out at 900 °C for different H2/N2/H2S fuel gas atmospheres, current densities and Ni/CGO anodes. The poisoning periods of the cells varied from 200 to 1500 h. The possibility of stable long-term Ni/CGO anode operation under sulfur exposure is established and the critical operating regime is outlined. Depending on the operating conditions, two degradation phenomena can be observed. Small degradation of the ohmic resistance was witnessed for sulfur exposure times of approximately 1000 h. Moreover, degradation of the anode charge transfer resistance was observed to be triggered by the combination of a small anodic potential step and high sulfur coverage on Ni. The microstructural evolution of altered Ni/CGO anodes was examined post-mortem by means of SEM and FIB/SEM, and is correlated to the anode performance degradation under critical operating conditions, establishing Ni depletion, porosity increase and a tripe phase boundary density decrease in the anode functional layer. It is shown that short-term sulfur poisoning behavior can be used to assess long-term stability.

Integrating critical interface elements for intuitive single-display aviation control of UAVs

NASA Astrophysics Data System (ADS)

Cooper, Joseph L.; Goodrich, Michael A.

2006-05-01

Although advancing levels of technology allow UAV operators to give increasingly complex commands with expanding temporal scope, it is unlikely that the need for immediate situation awareness and local, short-term flight adjustment will ever be completely superseded. Local awareness and control are particularly important when the operator uses the UAV to perform a search or inspection task. There are many different tasks which would be facilitated by search and inspection capabilities of a camera-equipped UAV. These tasks range from bridge inspection and news reporting to wilderness search and rescue. The system should be simple, inexpensive, and intuitive for non-pilots. An appropriately designed interface should (a) provide a context for interpreting video and (b) support UAV tasking and control, all within a single display screen. In this paper, we present and analyze an interface that attempts to accomplish this goal. The interface utilizes a georeferenced terrain map rendered from publicly available altitude data and terrain imagery to create a context in which the location of the UAV and the source of the video are communicated to the operator. Rotated and transformed imagery from the UAV provides a stable frame of reference for the operator and integrates cleanly into the terrain model. Simple icons overlaid onto the main display provide intuitive control and feedback when necessary but fade to a semi-transparent state when not in use to avoid distracting the operator's attention from the video signal. With various interface elements integrated into a single display, the interface runs nicely on a small, portable, inexpensive system with a single display screen and simple input device, but is powerful enough to allow a single operator to deploy, control, and recover a small UAV when coupled with appropriate autonomy. As we present elements of the interface design, we will identify concepts that can be leveraged into a large class of UAV applications.

Critical-thinking ability in respiratory care students and its correlation with age, educational background, and performance on national board examinations.

PubMed

Wettstein, Richard B; Wilkins, Robert L; Gardner, Donna D; Restrepo, Ruben D

2011-03-01

Critical thinking is an important characteristic to develop in respiratory care students. We used the short-form Watson-Glaser Critical Thinking Appraisal instrument to measure critical-thinking ability in 55 senior respiratory care students in a baccalaureate respiratory care program. We calculated the Pearson correlation coefficient to assess the relationships between critical-thinking score, age, and student performance on the clinical-simulation component of the national respiratory care boards examination. We used chi-square analysis to assess the association between critical-thinking score and educational background. There was no significant relationship between critical-thinking score and age, or between critical-thinking score and student performance on the clinical-simulation component. There was a significant (P = .04) positive association between a strong science-course background and critical-thinking score, which might be useful in predicting a student's ability to perform in areas where critical thinking is of paramount importance, such as clinical competencies, and to guide candidate-selection for respiratory care programs.

Children's Literature Review: Excerpts from Reviews, Criticism, and Commentary on Books for Children and Young People. Volume 1.

ERIC Educational Resources Information Center

Block, Ann, Ed.; Riley, Carolyn, Ed.

This is the first volume of a semiannual children's literature review reference series, each volume of which will present criticism of about 40 authors and will include excerpts from more than 45 books and from various issues of about 35 periodicals. A short paragraph following each author listing identifies the author by nationality, principal…

Comprehension of Critical News Items as Expressed by College Students and Adults in Business, Industry, and Religion.

ERIC Educational Resources Information Center

Adams, Effie Kaye; Scott, Elois M.

College students were compared to adults for their reading comprehension of news items on two critical issues of national concern. The subjects were 109 adults and 97 college students who read ten short magazine articles on the Iran-United States hostage crisis and the U.S. energy problem. After reading the articles, the subjects' comprehension…

The effectiveness of noninvasive interventions for musculoskeletal thoracic spine and chest wall pain: a systematic review by the Ontario Protocol for Traffic Injury Management (OPTIMa) collaboration.

PubMed

Southerst, Danielle; Marchand, Andrée-Anne; Côté, Pierre; Shearer, Heather M; Wong, Jessica J; Varatharajan, Sharanya; Randhawa, Kristi; Sutton, Deborah; Yu, Hainan; Gross, Douglas P; Jacobs, Craig; Goldgrub, Rachel; Stupar, Maja; Mior, Silvano; Carroll, Linda J; Taylor-Vaisey, Anne

2015-09-01

The purpose of this study was to critically appraise and synthesize evidence on the effectiveness of noninvasive interventions, excluding pharmacological treatments, for musculoskeletal thoracic pain. Randomized controlled trials (RCTs), cohort studies, and case-control studies evaluating the effectiveness of noninvasive interventions were eligible. We searched MEDLINE, EMBASE, PsycINFO, and the Cochrane Central Register of Controlled Trials accessed through Ovid Technologies, Inc, and CINAHL Plus with Full Text accessed through EBSCOhost from 1990 to 2015. Our search strategies combined controlled vocabulary relevant to each database (eg, MeSH for MEDLINE) and text words relevant to our research question and the inclusion criteria. Random pairs of independent reviewers screened studies for relevance and critically appraised relevant studies using the Scottish Intercollegiate Guidelines Network criteria. Studies with a low risk of bias were synthesized following best evidence synthesis principles. We screened 6988 articles and critically appraised 2 studies. Both studies had a low risk of bias and were included in our synthesis. One RCT compared thoracic spinal manipulation, needle acupuncture, and placebo electrotherapy for recent thoracic spine pain. There were statistically significant but clinically nonimportant short-term reductions in pain favoring manipulation. There were no differences between acupuncture and placebo electrotherapy. Another RCT compared a multimodal program of care and a session of education for recent musculoskeletal chest wall pain. The multimodal care resulted in statistically significant but clinically nonimportant short-term reductions in pain over education. However, participants receiving multimodal care were more likely to report important improvements in chest pain. Quality evidence on the management of musculoskeletal thoracic pain is sparse. The current evidence suggests that compared to placebo, spinal manipulation is associated with a small and clinically nonimportant reduction in pain intensity and that acupuncture leads to similar outcomes as placebo. Furthermore, a multimodal program of care (ie, manual therapy, soft tissue therapy, exercises, heat/ice, and advice) and a single education session lead to similar pain reduction for recent-onset musculoskeletal chest wall pain. However, patients who receive multimodal care are more likely to report pain improvements. Copyright © 2015 National University of Health Sciences. Published by Elsevier Inc. All rights reserved.

Psychosocial short stature with psychosis: a case report.

PubMed

Wattchow, Naomi; Lee, Hsu-En; Brock, Philip

2015-02-01

Our objective was to report and describe a case of psychosocial short stature in an adolescent girl with psychotic features. Psychosocial short stature is a rare condition in which emotional stress or deprivation in childhood profoundly reduces growth, leading to persistent short stature. This disorder is variably known as psychosocial dwarfism, hyperphagic short stature or maternal deprivation dwarfism. In the literature, psychosocial short stature has not been associated previously with psychosis. We formulate that our patient's short stature, developmental regression and psychotic features were culminations of insecure mother-child attachment, personal traumatic experiences, immigrant status, high family expressed emotions and social isolation. Neuropsychiatric influences were critically regarded due to our patient's fluctuations in behaviour and affect, in the setting of cortical volume loss on brain MRI. Diagnostic hypotheses included childhood disintegrative disorder or childhood-onset schizophrenia. The management plan involved inpatient family psychoeducation, a pharmacological trial with an atypical antipsychotic and community mental health service follow-up for family therapy and psychotherapy. © The Royal Australian and New Zealand College of Psychiatrists 2014.

Development of a short course on management of critically ill patients with acute respiratory infection and impact on clinician knowledge in resource-limited ICUs.

PubMed

Diaz, Janet V; Ortiz, Justin R; Lister, Paula; Shindo, Nahoko; Adhikari, Neill K J

2018-05-04

The 2009 influenza A (H1N1) pandemic caused surges of patients in intensive care units (ICUs) in resource-limited settings. Several Ministries of Health requested clinical management guidance from the World Health Organization (WHO), which had not previously developed guidance regarding critically ill patients. To assess the acceptability and impact on knowledge of a short course about the management of critically ill patients with acute respiratory infections complicated by sepsis or acute respiratory distress syndrome delivered to clinicians in resource-limited ICUs. Over four years (2009-2013), WHO led the development, piloting, implementation, and preliminary evaluation of a three-day course that emphasized patient management based on evidence-based guidelines and used interactive adult-learner teaching methodology. International content experts (n=35) and instructional designers contributed to development. We assessed participants' satisfaction and content knowledge before and after the course. The course was piloted among clinicians in Trinidad and Tobago (n=29), Indonesia (n=38), and Vietnam (n=86); feedback from these courses contributed to the final version. In 2013, inaugural national courses were delivered in Tajikistan (n=28), Uzbekistan (n=39), and Azerbaijan (n=30). Participants rated the course highly and demonstrated increased immediate content knowledge after (vs. before) course completion (p<0.001). We found that it was feasible to create and deliver a focused critical care short course to clinicians in low- and middle-income countries. Collaboration between WHO, clinical experts, instructional designers, Ministries of Health, and local clinician-leaders facilitated course delivery. Future work should assess its impact on longer-term knowledge retention and on processes and outcomes of care. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Short-Term Health-Related Quality of Life of Critically Ill Children Following Daily Sedation Interruption.

PubMed

Vet, Nienke J; de Wildt, Saskia N; Verlaat, Carin W M; Mooij, Miriam G; Tibboel, Dick; de Hoog, Matthijs; Buysse, Corinne M P

2016-11-01

Our earlier pediatric daily sedation interruption trial showed that daily sedation interruption in addition to protocolized sedation in critically ill children does not reduce duration of mechanical ventilation, length of stay, or amounts of sedative drugs administered when compared with protocolized sedation only, but undersedation was more frequent in the daily sedation interruption + protocolized sedation group. We now report the preplanned analysis comparing short-term health-related quality of life and posttraumatic stress symptoms between the two groups. Preplanned prospective part of a randomized controlled trial. Two tertiary medical-surgical PICUs in the Netherlands. Critically ill children requiring mechanical ventilation. None. Eight weeks after a child's discharge from the PICU, health-related quality of life was assessed with the validated Child Health Questionnaire and, only for children above 4 years old, posttraumatic stress was assessed with the Dutch Children's Responses to Trauma Inventory. Additionally, health-related quality of life of all study patients was compared with Dutch normative data. Of the 113 patients from two participating centers in the original study, 96 patients were eligible for follow-up and 64 patients were included (response rate, 67%). No difference was found with respect to health-related quality of life between the two study groups. None of the eight children more than 4 years old showed posttraumatic stress symptoms. Daily sedation interruption in addition to protocolized sedation for critically ill children did not seem to have an effect on short-term health-related quality of life. Also in view of the earlier found absence of effect on clinical outcome, we cannot recommend the use of daily sedation interruption + protocolized sedation.

Implementation of a limited area ensemble meteorological system in a GRID and HPC environment

NASA Astrophysics Data System (ADS)

Marrocu, M.; Pusceddu, G.; Peneva, E.

2009-04-01

At present there is an ever increasing demand for reliable probabilistic short range weather forecast. At regional scale this kind of forecast is even more valuable especially in cases of high impact weather such as violent extra tropical storms which may result in loss of lives and properties due to wide-spread flooding and gale force winds. The Multi-Analysis Multi-Model (MAMM) approach is a relatively new method of Ensemble Prediction System (EPS) in which the single deterministic forecasts are combined using specific statistical techniques to estimate the probability of a certain event to develop. MAMM simulations are very demanding in terms of computer resources, requiring CPU time and storage capacity which a single organization is hardly to provide. Moreover operational short range weather prediction at regional scale is a time critical task wich has to be completed in less than a couple of hours to be really usable. In this presentation we will discuss the results of two project (GRIDA3: grida3.crs4.it, CYBERSAR: www.cybersar.com) financed by the Italian Ministry of Research (MIUR) in which we have implemented a MAMM EPS based on 3 limited area models (BOLAM, MM5 and WRF) fed with two different sets of Initial and Boundary Conditions (NCEP and ECMWF). The system has been ported on a PC cluster and made accessible by a specifically designed web portal (grida3.crs4.it/enginframe/premiagrid). This allows an authorized user to use the remote HPC resources behind the web portal, and to run the service (named PREMIAGRID) on demand setting only three parameter: the place in the world, the initial date and the time of integration. Results obtained with the porting of the PREMIAGRID service in the virtual grid of the CyberSAR project using the gLite middleware, will be also discussed.

Short- and long-term outcomes of 1000 adult lung transplant recipients at a single center.

PubMed

Kreisel, Daniel; Krupnick, Alexander S; Puri, Varun; Guthrie, Tracey J; Trulock, Elbert P; Meyers, Bryan F; Patterson, G Alexander

2011-01-01

Lung transplantation has become accepted therapy for end-stage pulmonary disease. The objective of this study was to review a single-institution experience of adult lung transplants. We reviewed 1000 adult lung transplants that were performed at Washington University between July 1988 and January 2009. Transplants were performed for emphysema (52%), cystic fibrosis (18.2%), pulmonary fibrosis (16.1%), and pulmonary vascular disease (7.2%). Overall recipient age was 48 ± 13 years with an increase from 43 ± 12 years (July 1988-November 1993) to 50 ± 14 years (June 2005-January 2009). Overall incidence of primary graft dysfunction was 22.1%. Hospital mortality was higher for patients who had primary graft dysfunction (primary graft dysfunction, 13.6%; no primary graft dysfunction, 4%; P < .001). Freedom from bronchiolitis obliterans syndrome was 84% at 1 year, 38.2% at 5 years, and 12.2% at 10 years. Survival at 1, 5, 10, and 15 years was 84%, 56.4%, 32.2%, and 17.8%, respectively. Five-year survival improved from 49.6% (July 1988-November 1993) to 62.1% (October 2001-June 2005). Primary graft dysfunction was associated with lower survival at 1, 5, and 10 years (primary graft dysfunction: 72.8%, 43.9%, and 18.7%, respectively; no primary graft dysfunction: 87.1%, 59.8%, and 35.7%, respectively, P < .001) and lower rates of freedom from bronchiolitis obliterans syndrome (primary graft dysfunction: 78%, 27.5%, and 8.5%, respectively; no primary graft dysfunction: 85.4%, 40.7%, and 13.1%, respectively, P = .007). Five-year survival has improved over the study period, but long-term outcomes are limited by bronchiolitis obliterans syndrome. Primary graft dysfunction is associated with higher rates of bronchiolitis obliterans syndrome and impaired short- and long-term survival. A better understanding of primary graft dysfunction and bronchiolitis obliterans syndrome is critical to improve outcomes. Copyright © 2011 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

Molecular dynamics simulations of diffusion and clustering along critical isotherms of medium-chain n-alkanes.

PubMed

Mutoru, J W; Smith, W; O'Hern, C S; Firoozabadi, A

2013-01-14

Understanding the transport properties of molecular fluids in the critical region is important for a number of industrial and natural systems. In the literature, there are conflicting reports on the behavior of the self diffusion coefficient D(s) in the critical region of single-component molecular systems. For example, D(s) could decrease to zero, reach a maximum, or remain unchanged and finite at the critical point. Moreover, there is no molecular-scale understanding of the behavior of diffusion coefficients in molecular fluids in the critical regime. We perform extensive molecular dynamics simulations in the critical region of single-component fluids composed of medium-chain n-alkanes-n-pentane, n-decane, and n-dodecane-that interact via anisotropic united-atom potentials. For each system, we calculate D(s), and average molecular cluster sizes κ(cl) and numbers N(cl) at various cluster lifetimes τ, as a function of density ρ in the range 0.2ρ(c) ≤ ρ ≤ 2.0ρ(c) at the critical temperature T(c). We find that D(s) decreases with increasing ρ but remains finite at the critical point. Moreover, for any given τ < 1.2 × 10(-12) s, κ(cl) increases with increasing ρ but is also finite at the critical point.

Can a double stranded DNA be unzipped by pulling a single strand?: phases of adsorbed DNA.

PubMed

Kapri, Rajeev

2009-04-14

We study the unzipping of a double stranded DNA (dsDNA) by applying an external force on a single strand while leaving the other strand free. We find that the dsDNA can be unzipped to two single strands if the external force exceeds a critical value. We obtain the phase diagram, which is found to be different from the phase diagram of unzipping by pulling both the strands in opposite directions. In the presence of an attractive surface near DNA, the phase diagram gets modified drastically and shows richer surprises including a critical end point and a triple point.

Rumination and self-reflection in stress narratives and relations to psychological functioning.

PubMed

Marin, Kelly A; Rotondo, Elena K

2017-01-01

The longitudinal study aims to expand what is known about the costs and benefits of narrating stressful experiences by exploring changes in rumination within the narrative process and comparing it to changes in self-reflection. Rumination (e.g., brooding, self-criticism, and negative emotions) and self-reflection were measured in stress narratives of 56 college students. There were several goals: (1) examine changes in narrative rumination and narrative self-reflection over 3 days of writing, (2) examine the relations among the changes in narrative rumination variables and narrative self-reflection and (3) examine how changes in narrative rumination and narrative self-reflection relate to multiple measures of psychological functioning. Overall, individuals increased self-reflection over the 3-day writing task. Individuals who increased ruminative brooding across the 3 days of writing showed lower ego identity development (short term and long term) and self-esteem (short term), while increased self-criticism was positively correlated with identity distress (short term). Implications of the different aspects of narrative rumination, specifically in the context of stressful experiences, are discussed.

GENUS DESULFOMICROBIUM

EPA Science Inventory

Short, straight rod- or ellipsoidal-shaped cells (0.5-0.9 x 1.3-2.9 |m) with rounded ends, either singly or in pairs (Sharak Genthner et al., 1994). Gram-negative stain reaction and cell-wall structure. Cells are motile, usually by a single polar flagellum. Obligate anaerobe. End...

Critical Thresholds in Earth-System Dynamics

NASA Astrophysics Data System (ADS)

Rothman, D.

2017-12-01

The history of the Earth system is a story of change. Some changesare gradual and benign, but others, especially those associated withcatastrophic mass extinction, are relatively abrupt and destructive.What sets one group apart from the other? Here I hypothesize thatperturbations of Earth's carbon cycle lead to mass extinction if theyexceed either a critical rate at long time scales or a critical sizeat short time scales. By analyzing 31 carbon-isotopic events duringthe last 542 million years, I identify the critical rate with a limitimposed by mass conservation. Further analysis identifies thecrossover timescale separating fast from slow events with thetimescale of the ocean's homeostatic response to a change in pH. Theproduct of the critical rate and the crossover timescale then yieldsthe critical size. The modern critical size for the marine carboncycle is roughly similar to the mass of carbon that human activitieswill likely have added to the oceans by the year 2100.

Performance comparison of single and dual metal dielectrically modulated TFETs for the application of label free biosensor

NASA Astrophysics Data System (ADS)

Verma, Madhulika; Sharma, Dheeraj; Pandey, Sunil; Nigam, Kaushal; Kondekar, P. N.

2017-01-01

In this work, we perform a comparative analysis between single and dual metal dielectrically modulated tunnel field-effect transistors (DMTFETs) for the application of label free biosensor. For this purpose, two different gate material with work-function as ϕM 1 and ϕM 2 are used in short-gate DMTFET, where ϕM 1 represents the work-function of gate M1 near to the drain end, while ϕM 2 denotes the work-function of gate M2 near to the source end. A nanogap cavity in the gate dielectric is formed by removing the selected portion of gate oxide for sensing the biomolecules. To investigate the sensitivity of these biosensors, dielectric constant and charge density within the cavity region are considered as governing parameters. The work-function of gate M2 is optimized and considered less than M1 to achieve abruptness at the source/channel junction, which results in better tunneling and improved ON-state current. The ATLAS device simulations show that dual metal SG-DMTFETs attains higher ON-state current and drain current sensitivity as compared to its counterpart device. Finally, a dual metal short-gate (DSG) biosensor is compared with the single metal short-gate (SG), single metal full-gate (FG), and dual metal full-gate (DFG) biosensors to analyse structurally enhanced conjugation effect on gate-channel coupling.

Short wavelength laser

DOEpatents

Hagelstein, P.L.

1984-06-25

A short wavelength laser is provided that is driven by conventional-laser pulses. A multiplicity of panels, mounted on substrates, are supported in two separated and alternately staggered facing and parallel arrays disposed along an approximately linear path. When the panels are illuminated by the conventional-laser pulses, single pass EUV or soft x-ray laser pulses are produced.

Harvesting systems and costs for short rotation poplar

Treesearch

B. Rummer; D. Mitchell

2013-01-01

The objective of this review is to compare the cost of coppice and longer rotation poplar harvesting technology. Harvesting technology for short rotation poplar has evolved over the years to address both coppice harvest and single-stem harvest systems. Two potential approaches for coppice harvesting are modified forage harvesters and modified mulcher-balers. Both of...

Power and action in critical theory across disciplines: implications for critical community psychology.

PubMed

Davidson, Heather; Evans, Scot; Ganote, Cynthia; Henrickson, Jorie; Jacobs-Priebe, Lynette; Jones, Diana L; Prilleltensky, Isaac; Riemer, Manuel

2006-09-01

Although critical scholarship and community psychology share similar aspirations, the links between them remain unexplored and under-theorized. In this article we explore the implications of critical scholarship in various specialties for the field of community psychology. To understand the contributions of critical scholarship to a theory of power and action for social change, we conducted a systematic analysis of a ten-year period of publications in seven journals associated with the critical scholarship tradition. We created precise criteria for the concepts of power and action and applied them to the publications. Results indicate an interesting paradox at play. Whereas community psychology is more action oriented than critical scholarship, its actions fall short of challenging institutionalized power structures and the status quo; and whereas critical scholarship is more challenging of the status quo than community psychology in theory, it has failed to produce viable actions that challenge the status quo. We discuss the implications of this state of affairs for the development of a more critical community psychology.

Criticality of Low-Energy Protons in Single-Event Effects Testing of Highly-Scaled Technologies

NASA Technical Reports Server (NTRS)

Pellish, Jonathan A.; Marshall, Paul W.; Rodbell, Kenneth P.; Gordon, Michael S.; LaBel, Kenneth A.; Schwank, James R.; Dodds, Nathaniel A.; Castaneda, Carlos M.; Berg, Melanie D.; Kim, Hak S.;

Critical Current Statistics of a Graphene-Based Josephson Junction Infrared Single Photon Detector

NASA Astrophysics Data System (ADS)

Walsh, Evan D.; Lee, Gil-Ho; Efetov, Dmitri K.; Heuck, Mikkel; Crossno, Jesse; Taniguchi, Takashi; Watanabe, Kenji; Ohki, Thomas A.; Kim, Philip; Englund, Dirk; Fong, Kin Chung

Graphene is a promising material for single photon detection due to its broadband absorption and exceptionally low specific heat. We present a photon detector using a graphene sheet as the weak link in a Josephson junction (JJ) to form a threshold detector for single infrared photons. Calculations show that such a device could experience temperature changes of a few hundred percent leading to sub-Hz dark count rates and internal efficiencies approaching unity. We have fabricated the graphene-based JJ (gJJ) detector and measure switching events that are consistent with single photon detection under illumination by an attenuated laser. We study the physical mechanism for these events through the critical current behavior of the gJJ as a function of incident photon flux.

Stabilization of bacterially expressed erythropoietin by single site-specific introduction of short branched PEG chains at naturally occurring glycosylation sites.

PubMed

Hoffmann, E; Streichert, K; Nischan, N; Seitz, C; Brunner, T; Schwagerus, S; Hackenberger, C P R; Rubini, M

2016-05-24

The covalent attachment of polyethylene glycol (PEG) to therapeutic proteins can improve their physicochemical properties. In this work we utilized the non-natural amino acid p-azidophenylalanine (pAzF) in combination with the chemoselective Staudinger-phosphite reaction to install branched PEG chains to recombinant unglycosylated erythropoietin (EPO) at each single naturally occurring glycosylation site. PEGylation with two short 750 or 2000 Da PEG units at positions 24, 38, or 83 significantly decreased unspecific aggregation and proteolytic degradation while biological activity in vitro was preserved or even increased in comparison to full-glycosylated EPO. This site-specific bioconjugation approach permits to analyse the impact of PEGylation at single positions. These results represent an important step towards the engineering of site-specifically modified EPO variants from bacterial expression with increased therapeutic efficacy.

Single frequency RF powered ECG telemetry system

NASA Technical Reports Server (NTRS)

Ko, W. H.; Hynecek, J.; Homa, J.

1979-01-01

It has been demonstrated that a radio frequency magnetic field can be used to power implanted electronic circuitry for short range telemetry to replace batteries. A substantial reduction in implanted volume can be achieved by using only one RF tank circuit for receiving the RF power and transmitting the telemetered information. A single channel telemetry system of this type, using time sharing techniques, was developed and employed to transmit the ECG signal from Rhesus monkeys in primate chairs. The signal from the implant is received during the period when the RF powering radiation is interrupted. The ECG signal is carried by 20-microsec pulse position modulated pulses, referred to the trailing edge of the RF powering pulse. Satisfactory results have been obtained with this single frequency system. The concept and the design presented may be useful for short-range long-term implant telemetry systems.

[THE INFLUENCE OF SEROTONIN TRANSPORTER AND MONOAMINE OXIDASE A GENES POLYMORPHISM ON PSYCHO-EMOTION AND KARYOLOGICAL STABILITY OF ATHLETES].

PubMed

Kalaev, V N; Nechaeva, M S; Korneeva, O S; Cherenkov, D A

2015-11-01

The influence of polymorphism of the serotonin transporter and monoamine oxidase A genes, associated with man's aggressiveness on the psycho-emotional state and karyological status of single combat athletes. It was revealed that the carriers of less active ("short"), monoamine oxidase A gene variant have a high motivation to succeed and less rigidity and frustrated, compared to the carriers of more active ("long") version of the gene. Heterozygote carriers of less active ("short") variant of the serotonin transporter gene 5-HTTL had more physical aggression, guilt and were less frustrated compared with carriers of two long alleles. It has been revealed the association of studied genes with the karyological status of athletes. So fighters who are carriers of the short and long alleles of the serotonin transporter gene had more cells with nuclear abnormalities in the buccal epithelium than single combat athletes which both alleles were long.

Precise gene editing of chicken Na+/H+ exchange type 1 (chNHE1) confers resistance to avian leukosis virus subgroup J (ALV-J).

PubMed

Lee, Hong Jo; Lee, Kyung Youn; Jung, Kyung Min; Park, Kyung Je; Lee, Ko On; Suh, Jeong-Yong; Yao, Yongxiu; Nair, Venugopal; Han, Jae Yong

2017-12-01

Avian leukosis virus subgroup J (ALV-J), first isolated in the late 1980s, has caused economic losses to the poultry industry in many countries. As all chicken lines studied to date are susceptible to ALV infection, there is enormous interest in developing resistant chicken lines. The ALV-J receptor, chicken Na + /H + exchange 1 (chNHE1) and the critical amino acid sequences involved in viral attachment and entry have already been characterized. However, there are no reported attempts to induce resistance to the virus by targeted genome modification of the receptor sequences. In an attempt to induce resistance to ALV-J infection, we used clustered regularly interspaced short palindromic repeats (CRISPR)-associated (CRISPR/Cas9)-based genome editing approaches to modify critical residues of the chNHE1 receptor in chicken cells. The susceptibility of the modified cell lines to ALV-J infection was examined using enhanced green fluorescent protein (EGFP)-expressing marker viruses. We showed that modifying the chNHE1 receptor by artificially generating a premature stop codon induced absolute resistance to viral infection, with mutations of the tryptophan residue at position 38 (Trp38) being very critical. Single-stranded oligodeoxynucleotide (ssODN)-mediated targeted recombination of the Trp38 region revealed that deletions involving the Trp38 residue were most effective in conferring resistance to ALV-J. Moreover, protein structure analysis of the chNHE1 receptor sequence suggested that its intrinsically disordered region undergoes local conformational changes through genetic alteration. Collectively, these results demonstrate that targeted mutations on chNHE1 alter the susceptibility to ALV-J and the technique is expected to contribute to develop disease-resistant chicken lines. Copyright © 2017 Elsevier Ltd. All rights reserved.

The physiological and emotional effects of touch: Assessing a hand-massage intervention with high self-critics.

PubMed

Maratos, Frances A; Duarte, Joana; Barnes, Christopher; McEwan, Kirsten; Sheffield, David; Gilbert, Paul

2017-04-01

Research demonstrates that highly self-critical individuals can respond negatively to the initial introduction of a range of therapeutic interventions. Yet touch as a form of therapeutic intervention in self-critical individuals has received limited prior investigation, despite documentation of its beneficial effects for well-being. Using the Forms of Self-Criticism/Self-Reassuring Scale, 15 high- and 14 low- self-critical individuals (from a sample of 139 females) were recruited to assess how self-criticism impacts upon a single instance of focused touch. All participants took part in a hand massage- and haptic control- intervention. Salivary cortisol and alpha amylase, as well as questionnaire measures of emotional responding were taken before and after the interventions. Following hand massage, analyses revealed cortisol decreased significantly across all participants; and that significant changes in emotional responding reflected well-being improvements across all participants. Supplementary analyses further revealed decreased alpha amylase responding to hand massage as compared to a compassion-focused intervention in the same (highly self-critical) individuals. Taken together, the physiological and emotional data indicate high self-critical individuals responded in a comparable manner to low self-critical individuals to a single instance of hand massage. This highlights that focused touch may be beneficial when first engaging highly self-critical individuals with specific interventions. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

A Study of the Effects of Variation of Short-Term Memory Load, Reading Response Length, and Processing Hierarchy on TOEFL Listening Comprehension Item Performance. Report 33.

ERIC Educational Resources Information Center

Henning, Grant

Criticisms of the Test of English as a Foreign Language (TOEFL) have included speculation that the listening test places too much burden on short-term memory as compared with comprehension, that a knowledge of reading is required to respond successfully, and that many items appear to require mere recall and matching rather than higher-order…

Elective gastropexy with a reusable single-incision laparoscopic surgery port in dogs: 14 cases (2012-2013).

PubMed

Stiles, Mandy; Case, J Brad; Coisman, James

2016-08-01

OBJECTIVE To describe the technique, clinical findings, and short-term outcome in dogs undergoing laparoscopic-assisted incisional gastropexy with a reusable single-incision surgery port. DESIGN Retrospective case series. ANIMALS 14 client-owned dogs. PROCEDURES Medical records of dogs referred for elective laparoscopic gastropexy between June 2012 and August 2013 were reviewed. History, signalment, results of physical examination and preoperative laboratory testing, surgical procedure, duration of surgery, postoperative complications, duration of hospital stay, and short-term outcome were recorded. All patients underwent general anesthesia and were positioned in dorsal recumbency. After an initial limited laparoscopic exploration, single-incision laparoscopic-assisted gastropexy was performed extracorporeally in all dogs via a conical port placed in a right paramedian location. Concurrent procedures included laparoscopic ovariectomy (n = 4), gastric biopsy (2), and castration (7). Short-term outcome was evaluated. RESULTS Median duration of surgery was 76 minutes (range, 40 to 90 minutes). Intraoperative complications were minor and consisted of loss of pneumoperitoneum in 2 of 14 dogs. A postoperative surgical site infection occurred in 1 dog and resolved with standard treatment. Median duration of follow-up was 371 days (range, 2 weeks to 1.5 years). No dogs developed gastric dilation-volvulus during the follow-up period, and all owners were satisfied with the outcome. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that single-incision laparoscopic-assisted gastropexy with a reusable conical port was feasible and effective in appropriately selected cases. Investigation of the potential benefits of this reusable port versus single-use devices for elective gastropexy in dogs is warranted.

Self-organized criticality in neural networks

NASA Astrophysics Data System (ADS)

Makarenkov, Vladimir I.; Kirillov, A. B.

1991-08-01

Possible mechanisms of creating different types of persistent states for informational processing are regarded. It is presented two origins of criticalities - self-organized and phase transition. A comparative analyses of their behavior is given. It is demonstrated that despite a likeness there are important differences. These differences can play a significant role to explain the physical issue of such highest functions of the brain as a short-term memory and attention. 1.

A single mild fluid percussion injury induces short-term behavioral and neuropathological changes in the Long-Evans rat: support for an animal model of concussion.

PubMed

Shultz, Sandy R; MacFabe, Derrick F; Foley, Kelly A; Taylor, Roy; Cain, Donald P

2011-10-31

Brain concussion is a serious public health concern and is associated with short-term cognitive impairments and behavioral disturbances that typically occur in the absence of significant brain damage. The current study addresses the need to better understand the effects of a mild lateral fluid percussion injury on rat behavior and neuropathology in an animal model of concussion. Male Long-Evans rats received either a single mild fluid percussion injury or a sham-injury, and either a short (24h) or long (4 weeks) post-injury recovery period. After recovery, rats underwent a detailed behavioral analysis consisting of tests for rodent anxiety, cognition, social behavior, sensorimotor function, and depression-like behavior. After testing all rats were sacrificed and brains were examined immunohistochemically with markers for microglia/macrophage activation, reactive astrocytosis, and axonal injury. Injured rats (mean injury force: 1.20 ±.03 atm) displayed significant short-term cognitive impairments in the water maze and significantly more anxiolytic-like behavior in the elevated-plus maze compared to sham controls. Neuropathological analysis of the brains of injured rats showed an acute increase in reactive astrogliosis and activated microglia in cortex and evidence of axonal injury in the corpus callosum. There were no significant long-term effects on any behavioral or neuropathological measure 4 weeks after injury. These short-term behavioral and neuropathological changes are consistent with findings in human patients suffering a brain concussion, and provide further evidence for the use of a single mild lateral fluid percussion injury to study concussion in the rat. Copyright © 2011 Elsevier B.V. All rights reserved.

Time of flight emission spectroscopy of laser produced nickel plasma: Short-pulse and ultrafast excitations

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

Smijesh, N.; Chandrasekharan, K.; Joshi, Jagdish C.

2014-07-07

We report the experimental investigation and comparison of the temporal features of short-pulse (7 ns) and ultrafast (100 fs) laser produced plasmas generated from a solid nickel target, expanding into a nitrogen background. When the ambient pressure is varied in a large range of 10⁻⁶Torr to 10²Torr, the plume intensity is found to increase rapidly as the pressure crosses 1 Torr. Time of flight (TOF) spectroscopy of emission from neutral nickel (Ni I) at 361.9 nm (3d⁹(²D) 4p → 3d⁹(²D) 4s transition) reveals two peaks (fast and slow species) in short-pulse excitation and a single peak in ultrafast excitation. Themore » fast and slow peaks represent recombined neutrals and un-ionized neutrals, respectively. TOF emission from singly ionized nickel (Ni II) studied using the 428.5 nm (3p⁶3d⁸(³P) 4s→ 3p⁶3d⁹ 4s) transition shows only a single peak for either excitation. Velocities of the neutral and ionic species are determined from TOF measurements carried out at different positions (i.e., at distances of 2 mm and 4 mm, respectively, from the target surface) on the plume axis. Measured velocities indicate acceleration of neutrals and ions, which is caused by the Coulomb pull of the electrons enveloping the plume front in the case of ultrafast excitation. Both Coulomb pull and laser-plasma interaction contribute to the acceleration in the case of short-pulse excitation. These investigations provide new information on the pressure dependent temporal behavior of nickel plasmas produced by short-pulse and ultrafast laser pulses, which have potential uses in applications such as pulsed laser deposition and laser-induced nanoparticle generation.« less

Start-to-end simulation of single-particle imaging using ultra-short pulses at the European X-ray Free-Electron Laser

DOE PAGES

Fortmann-Grote, Carsten; Buzmakov, Alexey; Jurek, Zoltan; ...

2017-09-01

Single-particle imaging with X-ray free-electron lasers (XFELs) has the potential to provide structural information at atomic resolution for non-crystalline biomolecules. This potential exists because ultra-short intense pulses can produce interpretable diffraction data notwithstanding radiation damage. This paper explores the impact of pulse duration on the interpretability of diffraction data using comprehensive and realistic simulations of an imaging experiment at the European X-ray Free-Electron Laser. In conclusion, it is found that the optimal pulse duration for molecules with a few thousand atoms at 5 keV lies between 3 and 9 fs.

Three-dimensional single-mode nonlinear ablative Rayleigh-Taylor instability

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

Yan, R.; Aluie, H.; Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14627

The nonlinear evolution of the single-mode ablative Rayleigh-Taylor instability is studied in three dimensions. As the mode wavelength approaches the cutoff of the linear spectrum (short-wavelength modes), it is found that the three-dimensional (3D) terminal bubble velocity greatly exceeds both the two-dimensional (2D) value and the classical 3D bubble velocity. Unlike in 2D, the 3D short-wavelength bubble velocity does not saturate. The growing 3D bubble acceleration is driven by the unbounded accumulation of vorticity inside the bubble. The vorticity is transferred by mass ablation from the Rayleigh-Taylor spikes to the ablated plasma filling the bubble volume.

Single- and double-photoionization cross sections of atomic nitrogen from threshold to 31 A

NASA Technical Reports Server (NTRS)

Samson, James A. R.; Angel, G. C.

1990-01-01

The relative photoionization cross section of atomic nitrogen for the production of singly and doubly charged ions has been measured from 44.3 to 275 A and from 520 to 852 A. The results have been made absolute by normalization to one-half of the molecular nitrogen cross section at short wavelengths. The smoothed atomic nitrogen cross sections sigma can be accurately represented, at short wavelengths, by the equation sigma(Mb) = 36,700 x (E exp-2.3) as a function of the photon energy E (eV), thereby allowing the cross sections to be extrapolated to the nitrogen K edge at 31 A.

Start-to-end simulation of single-particle imaging using ultra-short pulses at the European X-ray Free-Electron Laser

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

Fortmann-Grote, Carsten; Buzmakov, Alexey; Jurek, Zoltan

Single-particle imaging with X-ray free-electron lasers (XFELs) has the potential to provide structural information at atomic resolution for non-crystalline biomolecules. This potential exists because ultra-short intense pulses can produce interpretable diffraction data notwithstanding radiation damage. This paper explores the impact of pulse duration on the interpretability of diffraction data using comprehensive and realistic simulations of an imaging experiment at the European X-ray Free-Electron Laser. In conclusion, it is found that the optimal pulse duration for molecules with a few thousand atoms at 5 keV lies between 3 and 9 fs.

[Assessment of the distribution in the body and the dose on the respiratory tract and organs after single, short-term and long-term inhalation of americium-241].

PubMed

Malykhin, V M

1991-04-01

On the basis of comparison of publications on accidental human intake of americium-241 and animal experimental studies dosimetric characteristics were obtained reflecting the dynamics of accumulation, formation of the dose on the organs and parts of the respiratory tract, as well as of the 24-hour elimination from the organism of the mentioned radionuclide following single, short- and long-term administration of americium-241 from the air. Results were obtained with the use of computers for quantitative modelling of the most complete metabolic transport scheme of americium.

Pump-Induced, Dual-Frequency Switching in a Short-Cavity, Ytterbium-Doped Fiber Laser

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

Guan, W.; Marciante, J.R.

2008-07-23

Using a short linear cavity composed of a section of highly ytterbium-doped fiber surrounded by two fiber Bragg gratings, dual frequency switching is achieved by tuning the pump power of the laser. The dual-frequency switching is generated by the thermal effects of the absorbed pump in the ytterbium-doped fiber. At each frequency, the laser shows single-longitudinal-mode behavior. In each single-mode regime, the optical signal-to-noise ratio of the laser is greater than 50 dB. The dual-frequency, switchable, fiber laser can be designed for various applications by the careful selection of the two gratings.

Children's 5-HTTLPR genotype moderates the link between maternal criticism and attentional biases specifically for facial displays of anger.

PubMed

Gibb, Brandon E; Johnson, Ashley L; Benas, Jessica S; Uhrlass, Dorothy J; Knopik, Valerie S; McGeary, John E

2011-09-01

Theorists have proposed that negative experiences in childhood may contribute to the development of experience-specific information-processing biases, including attentional biases. There are also clear genetic influences on cognitive processes, with evidence that polymorphisms in specific candidate genes may moderate the impact of environmental stress on attentional biases (e.g., a functional polymorphism in the serotonin transporter gene; 5-HTTLPR). In the current study, we tested a gene×environment (G×E) model of risk for attentional biases. We hypothesised that children whose mothers exhibit high levels of expressed emotion criticism (EE-Crit) would display attentional biases specifically for angry, but not happy or sad, faces, and that this link would be stronger among children carrying one or two copies of the 5-HTTLPR short allele than among those homozygous for the long allele. Results generally supported these hypotheses, though we found that carriers of the 5-HTTLPR short allele who also had a critical mother exhibited attentional avoidance of angry faces rather than preferential attention.

Children’s 5-HTTLPR genotype moderates the link between maternal criticism and attentional biases specifically for facial displays of anger

PubMed Central

Gibb, Brandon E.; Johnson, Ashley L.; Benas, Jessica S.; Uhrlass, Dorothy J.; Knopik, Valerie S.; McGeary, John E.

2011-01-01

Theorists have proposed that negative experiences in childhood may contribute to the development of experience-specific information-processing biases, including attentional biases. There are also clear genetic influences on cognitive processes, with evidence that polymorphisms in specific candidate genes may moderate the impact of environmental stress on attentional biases (e.g., a functional polymorphism in the serotonin transporter gene [5-HTTLPR]). In the current study, we tested a gene × environment (G × E) model of risk for attentional biases. We hypothesized that children whose mothers exhibit high levels of expressed emotion criticism (EE-Crit) would display attentional biases specifically for angry, but not happy or sad, faces, and that this link would be stronger among children carrying one or two copies of the 5-HTTLPR short allele than among those homozygous for the long allele. Results generally supported these hypotheses, though we found that carriers of the 5-HTTLPR short allele who also had a critical mother exhibited attentional avoidance of angry faces rather than preferential attention. PMID:21895572

Type-I superconductivity in YbSb2 single crystals

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

Zhao, Liang L.; Lausberg, Stefan; Kim, Hyunsoo

2012-06-25

We present evidence of type-I superconductivity in YbSb2 single crystals from dc and ac magnetization, heat capacity, and resistivity measurements. The critical temperature and critical field are determined to be Tc≈ 1.3 K and Hc≈ 55 Oe. A small Ginzburg-Landau parameter κ= 0.05, together with typical magnetization isotherms of type-I superconductors, small critical field values, a strong differential paramagnetic effect signal, and a field-induced change from second- to first-order phase transition, confirms the type-I nature of the superconductivity in YbSb2. A possible second superconducting state is observed in the radio-frequency susceptibility measurements, with Tc(2)≈ 0.41 K and Hc(2)≈ 430 Oe.

An isothermal amplification reactor with an integrated isolation membrane for point-of-care detection of infectious diseases

PubMed Central

Liu, Changchun; Geva, Eran; Mauk, Michael; Qiu, Xianbo; Abrams, William R.; Malamud, Daniel; Curtis, Kelly; Owen, S. Michele; Bau, Haim H.

2015-01-01

A simple, point of care, inexpensive, disposable cassette for the detection of nucleic acids extracted from pathogens was designed, constructed, and tested. The cassette utilizes a single reaction chamber for isothermal amplification of nucleic acids. The chamber is equipped with an integrated, flow-through, Flinders Technology Associates (Whatman FTA®) membrane for the isolation, concentration, and purification of DNA and/or RNA. The nucleic acids captured by the membrane are used directly as templates for amplification without elution, thus simplifying the cassette’s flow control. The FTA membrane also serves another critical role—enabling the removal of inhibitors that dramatically reduce detection sensitivity. Thermal control is provided with a thin film heater external to the cassette. The amplification process was monitored in real time with a portable, compact fluorescent reader. The utility of the integrated, single-chamber cassette was demonstrated by detecting the presence of HIV-1 in oral fluids. The HIV RNA was reverse transcribed and subjected to loop-mediated, isothermal amplification (LAMP). A detection limit of less than 10 HIV particles was demonstrated. The cassette is particularly suitable for resource poor regions, where funds and trained personnel are in short supply. The cassette can be readily modified to detect nucleic acids associated with other pathogens borne in saliva, urine, and other body fluids as well as in water and food. PMID:21455542

An isothermal amplification reactor with an integrated isolation membrane for point-of-care detection of infectious diseases.

PubMed

Liu, Changchun; Geva, Eran; Mauk, Michael; Qiu, Xianbo; Abrams, William R; Malamud, Daniel; Curtis, Kelly; Owen, S Michele; Bau, Haim H

2011-05-21

A simple, point of care, inexpensive, disposable cassette for the detection of nucleic acids extracted from pathogens was designed, constructed, and tested. The cassette utilizes a single reaction chamber for isothermal amplification of nucleic acids. The chamber is equipped with an integrated, flow-through, Flinders Technology Associates (Whatman FTA®) membrane for the isolation, concentration, and purification of DNA and/or RNA. The nucleic acids captured by the membrane are used directly as templates for amplification without elution, thus simplifying the cassette's flow control. The FTA membrane also serves another critical role-enabling the removal of inhibitors that dramatically reduce detection sensitivity. Thermal control is provided with a thin film heater external to the cassette. The amplification process was monitored in real time with a portable, compact fluorescent reader. The utility of the integrated, single-chamber cassette was demonstrated by detecting the presence of HIV-1 in oral fluids. The HIV RNA was reverse transcribed and subjected to loop-mediated, isothermal amplification (LAMP). A detection limit of less than 10 HIV particles was demonstrated. The cassette is particularly suitable for resource poor regions, where funds and trained personnel are in short supply. The cassette can be readily modified to detect nucleic acids associated with other pathogens borne in saliva, urine, and other body fluids as well as in water and food.

Analyzing the Historical Development and Transition of the Korean Health Care System.

PubMed

Lee, Sang-Yi; Kim, Chul-Woung; Seo, Nam-Kyu; Lee, Seung Eun

2017-08-01

Many economically advanced countries have attempted to minimize public expenditures and pursue privatization based on the principles of neo-liberalism. However, Korea has moved contrary to this global trend. This study examines why and how the Korean health care system was formed, developed, and transformed into an integrated, single-insurer, National Health Insurance (NHI) system. We describe the transition in the Korean health care system using an analytical framework that incorporates such critical variables as government economic development strategies and the relationships among social forces, state autonomy, and state power. This study focuses on how the relationships among social forces can change as a nation's economic development or governing strategy changes in response to changes in international circumstances such as globalization. The corporatist Social Health Insurance (SHI) system (multiple insurers) introduced in 1977 was transformed into the single-insurer NHI in July 2000. These changes were influenced externally by globalization and internally by political democratization, keeping Korea's private-dominant health care provision system unchanged over several decades. Major changes such as integration reform occurred, when high levels of state autonomy were ensured. The state's power (its policy capability), based on health care infrastructures, acts to limit the direction of any change in the health care system because it is very difficult to build the infrastructure for a health care system in a short timeframe.

Transition of Femtosecond-Filament-Solid Interactions from Single to Multiple Filament Regime

DOE PAGES

Skrodzki, P. J.; Burger, M.; Jovanovic, I.

2017-10-06

High-peak-power fs-laser filaments offer unique characteristics attractive to remote sensing via techniques such as remote laser-induced breakdown spectroscopy (R-LIBS). The dynamics of several ablation mechanisms following the interaction between a filament and a solid determines the emission strength and reproducibility of target plasma, which is of relevance for R-LIBS applications. Here, we investigate the space- and time-resolved dynamics of ionic and atomic emission from copper as well as the surrounding atmosphere in order to understand limitations of fs-filament-ablation for standoff energy delivery. Furthermore, we probe the shock front produced from filament-target interaction using time-resolved shadowgraphy and infer laser-material coupling efficienciesmore » for both single and multiple filament regimes through analysis of shock expansion with the Sedov model for point detonation. The results provide insight into plasma structure for the range of peak powers up to 30 times the critical power for filamentation P cr. Despite the stochastic nucleation of multiple filaments at peak-powers greater than 16 P cr, emission of ionic and neutral species increases with pump beam intensity, and short-lived nitrogen emission originating from the ambient is consistently observed. Ultimately, results suggest favorable scaling of emission intensity from target species on the laser pump energy, furthering the prospects for use of filament-solid interactions for remote sensing.« less

The role of readability in effective health communication: an experiment using a Japanese health information text on chronic suppurative otitis media.

PubMed

Sakai, Yukiko

2013-09-01

This study identifies the most significant readability factors and examines ways of improving and evaluating Japanese health information text in terms of ease of reading and understanding. Six different Japanese texts were prepared based on an original short text written by a medical doctor for a hospital web site intended for laypersons regarding chronic suppurative otitis media. Four were revised for single readability factor (syntax, vocabulary, or text structure) and two were modified in all three factors. Using a web-based survey, 270 high school students read one of the seven texts, including the original, completed two kinds of comprehension tests, and answered questions on their impressions of the text's readability. Significantly higher comprehension test scores were shown in the true or false test for a mixed text that presented important information first for better text structure. They were also found in the cloze test for a text using common vocabulary and a cohesive mixed text. Vocabulary could be a critical single readability factor when presumably combined with better text structure. Using multiple evaluation methods can help assess comprehensive readability. The findings on improvement and evaluation methods of readability can be applied to support effective health communication. © 2013 The authors. Health Information and Libraries Journal © 2013 Health Libraries Group Health Information and Libraries Journal.

Transition of Femtosecond-Filament-Solid Interactions from Single to Multiple Filament Regime

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

Skrodzki, P. J.; Burger, M.; Jovanovic, I.

High-peak-power fs-laser filaments offer unique characteristics attractive to remote sensing via techniques such as remote laser-induced breakdown spectroscopy (R-LIBS). The dynamics of several ablation mechanisms following the interaction between a filament and a solid determines the emission strength and reproducibility of target plasma, which is of relevance for R-LIBS applications. Here, we investigate the space- and time-resolved dynamics of ionic and atomic emission from copper as well as the surrounding atmosphere in order to understand limitations of fs-filament-ablation for standoff energy delivery. Furthermore, we probe the shock front produced from filament-target interaction using time-resolved shadowgraphy and infer laser-material coupling efficienciesmore » for both single and multiple filament regimes through analysis of shock expansion with the Sedov model for point detonation. The results provide insight into plasma structure for the range of peak powers up to 30 times the critical power for filamentation P cr. Despite the stochastic nucleation of multiple filaments at peak-powers greater than 16 P cr, emission of ionic and neutral species increases with pump beam intensity, and short-lived nitrogen emission originating from the ambient is consistently observed. Ultimately, results suggest favorable scaling of emission intensity from target species on the laser pump energy, furthering the prospects for use of filament-solid interactions for remote sensing.« less

Analyzing the Historical Development and Transition of the Korean Health Care System

PubMed Central

Lee, Sang-Yi; Kim, Chul-Woung; Seo, Nam-Kyu; Lee, Seung Eun

2017-01-01

Objectives Many economically advanced countries have attempted to minimize public expenditures and pursue privatization based on the principles of neo-liberalism. However, Korea has moved contrary to this global trend. This study examines why and how the Korean health care system was formed, developed, and transformed into an integrated, single-insurer, National Health Insurance (NHI) system. Methods We describe the transition in the Korean health care system using an analytical framework that incorporates such critical variables as government economic development strategies and the relationships among social forces, state autonomy, and state power. This study focuses on how the relationships among social forces can change as a nation’s economic development or governing strategy changes in response to changes in international circumstances such as globalization. Results The corporatist Social Health Insurance (SHI) system (multiple insurers) introduced in 1977 was transformed into the single-insurer NHI in July 2000. These changes were influenced externally by globalization and internally by political democratization, keeping Korea’s private-dominant health care provision system unchanged over several decades. Conclusion Major changes such as integration reform occurred, when high levels of state autonomy were ensured. The state’s power (its policy capability), based on health care infrastructures, acts to limit the direction of any change in the health care system because it is very difficult to build the infrastructure for a health care system in a short timeframe. PMID:28904846

Short-term fate of dietary dieldrin in the digestive tract of juvenile lake trout (Salvelinus namaycush)

USGS Publications Warehouse

Stewart, Donald J.; Stein, Roy A.

1974-01-01

Short-term fate of dietary dieldrin in the digestive tract of fishes is poorly known. Studies of the uptake, distribution, and elimination of chlorinated hydrocarbons have suggested that uptake or degradation is rapid in the intestine (GROSS 1969; MACEK et al. 1970; GRZENDA et al. 1970, 1971). The present study was designed to determine the short-term fate of a single oral dose of dieldrin in the digestive tract of lake trout (Salvelinus namaycush).

Sex-specific modulation of the gut microbiome and behavior in Siberian hamsters.

PubMed

Sylvia, Kristyn E; Jewell, Cathleen P; Rendon, Nikki M; St John, Emma A; Demas, Gregory E

2017-02-01

The gut microbiome is a diverse, host-specific, and symbiotic bacterial environment that is critical for mammalian survival and exerts a surprising yet powerful influence on brain and behavior. Gut dysbiosis has been linked to a wide range of physical and psychological disorders, including autism spectrum disorders and anxiety, as well as autoimmune and inflammatory disorders. A wealth of information on the effects of dysbiosis on anxiety and depression has been reported in laboratory model systems (e.g., germ-free mice); however, the effects of microbiome disruption on social behaviors (e.g., aggression) of non-model species that may be particularly important in understanding many aspects of physiology and behavior have yet to be fully explored. Here we assessed the sex-specific effects of a broad-spectrum antibiotic on the gut microbiome and its effects on social behaviors in male and female Siberian hamsters (Phodopus sungorus). In Experiment 1, we administered a broad-spectrum antibiotic on a short-term basis and found that antibiotic treatment altered the microbial communities in the gut in male and female hamsters. In Experiment 2, we tested the effects of single versus repeated antibiotic treatment (including a recovery phase) on behavior, and found that two, but not one, treatments caused marked decreases in aggressive behavior, but not other social behaviors, in males; aggression returned to normal levels following recovery. Antibiotic-treated females, in contrast, showed decreased aggression after a single treatment, with all other social behaviors unaffected. Unlike males, female aggression did not return to normal during either recovery period. The present findings demonstrate that modest antibiotic treatment results in marked disruption of the gut microbiome in hamsters, akin to research done in other rodent species and humans. Further, we show that treatment with a broad-spectrum antibiotic, which has dysbiotic effects, also has robust, sex-specific effects on aggression, a critical behavior in the survival and reproductive success of many rodent species. Copyright © 2016 Elsevier Inc. All rights reserved.

A new momentum integral method for approximating bed shear stress

NASA Astrophysics Data System (ADS)

Wengrove, M. E.; Foster, D. L.

2016-02-01

In nearshore environments, accurate estimation of bed stress is critical to estimate morphologic evolution, and benthic mass transfer fluxes. However, bed shear stress over mobile boundaries in wave environments is notoriously difficult to estimate due to the non-equilibrium boundary layer. Approximating the friction velocity with a traditional logarithmic velocity profile model is common, but an unsteady non-uniform flow field violates critical assumptions in equilibrium boundary layer theory. There have been several recent developments involving stress partitioning through an examination of the momentum transfer contributions that lead to improved estimates of the bed stress. For the case of single vertical profile observations, Mehdi et al. (2014) developed a full momentum integral-based method for steady-unidirectional flow that integrates the streamwise Navier-Stokes equation three times to an arbitrary position within the boundary layer. For the case of two-dimensional velocity observations, Rodriguez-Abudo and Foster (2014) were able to examine the momentum contributions from waves, turbulence and the bedform in a spatial and temporal averaging approach to the Navier-Stokes equations. In this effort, the above methods are combined to resolve the bed shear stress in both short and long wave dominated environments with a highly mobile bed. The confluence is an integral based approach for determining bed shear stress that makes no a-priori assumptions of boundary layer shape and uses just a single velocity profile time series for both the phase dependent case (under waves) and the unsteady case (under solitary waves). The developed method is applied to experimental observations obtained in a full scale laboratory investigation (Oregon State's Large Wave Flume) of the nearbed velocity field over a rippled sediment bed in oscillatory flow using both particle image velocimetry and a profiling acoustic Doppler velocimeter. This method is particularly relevant for small scale field observations and laboratory observations.

SHOX intragenic microsatellite analysis in patients with short stature.

PubMed

Ezquieta, Begoña; Cueva, Elena; Oliver, Antonio; Gracia, Ricardo

2002-02-01

SHOX haplo-insufficiency is considered the molecular basis of short stature in patients with Turner's syndrome, and gives rise to the short stature with mesomelic dysplasia and Madelung deformity of patients with Leri-Weill syndrome. Analysis of the intragenic SHOX microsatellite to define its utility in detecting SHOX haplo-insufficiency in patients with short stature. 207 patients with short stature (57 girls with Turner's syndrome [TS] [24 mosaicisms]; 73 children with isolated short stature [ISS]; 77 patients with short stature and skeletal disproportion) and 30 control subjects. DNA extraction and PCR amplification of the intragenic SHOX microsatellite, at the 5'-untranslated region. SSCP and partial sequencing of the SHOX gene in one patient with Madelung deformity and two SHOX alleles. DXS1055 (Xp) and DXS1192 (Xq) microsatellites were also analyzed, together with DXS233 and DXS234 at 0 and 2 cM of the pseudoautosomal region (PAR), in patients with one SHOX allele. 1. 93% of patients with TS had a single SHOX allele, and allele unbalance was detected in the remainder. 2. Patients with ISS were not different from the normal population with respect to SHOX heterozygosity (0.92 and 0.93, respectively; p = 0.997). 3. Patients with short stature and skeletal disproportion showed a higher frequency of SHOX homo/hemizygosity (0.27 vs 0.08; p = 0.027). 4. Five patients with short stature with SHOX haplo-insufficiency were detected: three had Madelung deformity (inherited Yq;Xp translocation, de novo PAR deletion, and SHOX microdeletion), and two had de novo/inherited Xp partial monosomy. The SHOX intragenic microsatellite might be a useful molecular marker to detect TS (including Xp distal deletions). SHOX haplo-insufficiency seems not to be an important contributor to ISS, but when skeletal disproportion is associated with short stature, a significant proportion of patients is found to have a single SHOX allele. Some of these patients were found to be SHOX haplo-insufficient upon molecular, cytogenetic and radiological examination.

Stability characteristics of a single-phase free convection loop

NASA Technical Reports Server (NTRS)

Creveling, H. F.; De Paz, J. F.; Baladi, J. Y.; Schoenhals, R. J.

1975-01-01

Experiments investigating the stability characteristics of a single-phase free convection loop are reported. Results of the study confirm the contention made by previous workers that instabilities near the thermodynamic critical point can occur for ordinary fluids as well as those with unusual behavior in the near-critical region. Such a claim runs counter to traditional beliefs, but it is supported by the observation of such instabilities for water at atmospheric pressure and moderate temperatures in the present work.

Freeway travel-time estimation and forecasting.

DOT National Transportation Integrated Search

2012-09-01

This project presents a microsimulation-based framework for generating short-term forecasts of travel time on freeway corridors. The microsimulation model that is developed (GTsim), replicates freeway capacity drop and relaxation phenomena critical f...

Hypoxia triggers short term potentiation of phrenic motoneuron discharge after chronic cervical spinal cord injury

PubMed Central

Lee, Kun-Ze; Sandhu, Milapjit S.; Dougherty, Brendan J.; Reier, Paul J.; Fuller, David D.

2014-01-01

Repeated exposure to hypoxia can induce spinal neuroplasticity as well as respiratory and somatic motor recovery after spinal cord injury (SCI). The purpose of the present study was to define the capacity for a single bout of hypoxia to trigger short-term plasticity in phrenic output after cervical SCI, and to determine the phrenic motoneuron (PhrMN) bursting and recruitment patterns underlying the response. Hypoxia-induced short term potentiation (STP) of phrenic motor output was quantified in anesthetized rats 11 wks following lateral spinal hemisection at C2 (C2Hx). A 3-min hypoxic episode (12–14% O2) always triggered STP of inspiratory burst amplitude, the magnitude of which was greater in phrenic bursting ipsilateral vs. contralateral to C2Hx. We next determined if STP could be evoked in recruited (silent) PhrMNs ipsilateral to C2Hx. Individual PhrMN action potentials were recorded during and following hypoxia using a “single fiber” approach. STP of bursting activity did not occur in cells initiating bursting at inspiratory onset, but was robust in recruited PhrMNs as well as previously active cells initiating bursting later in the inspiratory effort. We conclude that following chronic C2Hx, a single bout of hypoxia triggers recruitment of PhrMNs in the ipsilateral spinal cord with bursting that persists beyond the hypoxic exposure. The results provide further support for the use of short bouts of hypoxia as a neurorehabilitative training modality following SCI. PMID:25448009

Effect of notch depth of modified current collector on internal-short-circuit mitigation for lithium-ion battery

NASA Astrophysics Data System (ADS)

Wang, Meng; Noelle, Daniel J.; Shi, Yang; Le, Anh V.; Qiao, Yu

2018-01-01

Formation of internal short circuit (ISC) may result in catastrophic thermal runaway of lithium-ion battery (LIB). Among LIB cell components, direct contact between cathode and anode current collectors is most critical to the ISC behavior, yet is still relatively uninvestigated. In the current study, we analyze the effect of heterogeneity of current collector on the temperature increase of LIB cells subjected to mechanical abuse. The cathode current collector is modified by surface notches, so that it becomes effectively brittle and the ISC site can be isolated. Results from impact tests on LIB cells with modified current collectors suggest that their temperature increase can be negligible. The critical parameters include the failure strain and the failure work of modified current collector, both of which are related to the notch depth.

Telomere sister chromatid exchange in telomerase deficient murine cells.

PubMed

Wang, Yisong; Giannone, Richard J; Liu, Yie

2005-10-01

We have recently demonstrated that several types of genomic rearrangements (i.e., telomere sister chromatid exchange (T-SCE), genomic-SCE, or end-to-end fusions) were more often detected in long-term cultured murine telomerase deficient embryonic stem (ES) cells than in freshly prepared murine splenocytes, even through they possessed similar frequencies of critically short telomeres. The high rate of genomic rearrangements in telomerase deficient ES cells, when compared to murine splenocytes, may reflect the cultured cells' gained ability to protect chromosome ends with eroded telomeres allowing them to escape "end crisis". However, the possibility that ES cells were more permissive to genomic rearrangements than other cell types or that differences in the microenvironment or genetic background of the animals might consequentially determine the rate of T-SCEs or other genomic rearrangements at critically short telomeres could not be ruled out.

The Effect of Forward-Facing Steps on Stationary Crossflow Instability Growth and Breakdown

NASA Technical Reports Server (NTRS)

Eppink, Jenna L.

2018-01-01

The e?ect of a forward-facing step on stationary cross?ow transition was studied using standard stereo particle image velocimetry (PIV) and time-resolved PIV. Step heights ranging from 53 to 71% of the boundary-layer thickness were studied in detail. The steps above a critical step height of approximately 60% of the boundary-layer thickness had a signi?cant impact on the stationary cross?ow growth downstream of the step. For the critical cases, the stationary cross?ow amplitude grew suddenly downstream of the step, decayed for a short region, then grew again. The adverse pressure gradient upstream of the step resulted in a region of cross?ow reversal. A secondary set of vortices, rotating in the opposite direction to the primary vortices, developed underneath the uplifted primary vortices. The wall-normal velocity disturbance (V' ) created by these secondary vortices impacted the step, and is believed to feed into the strong vortex that developed downstream of the step. A large but very short negative cross?ow region formed for a short region downstream of the step due to a sharp inboard curvature of the streamlines near the wall. For the larger step height cases, a cross?ow-reversal region formed just downstream of the strong negative cross?ow region. This cross?ow reversal region is believed to play an important role in the growth of the stationary cross?ow vortices downstream of the step, and may be a good indication of the critical forward-facing step height.

Effects of a Single-Session Cognitive Enhancement Fitness Program on Serum Brain-Derived Neurotrophic Factor Levels and Cognitive Function in Middle-Aged Women

PubMed Central

Kim, Hyun Jun; Lee, Sang Yeoup; Lee, Hwa Gyeong; Cho, Yang Hee; Ko, Eun Mi

2018-01-01

Few studies have been undertaken to develop cognitive functional improvement-focused exercise programs and determine their effect. The objectives of this study were to evaluate the effects of a cognitive enhancement fitness program (CEFP) on short-term memory and serum brain-derived neurotrophic factor (BDNF) levels according to the cognitive state in middle-aged women. A total of 30 healthy volunteers aged 40–59 years were divided into two groups, that is, a mild cognitive impairment (MCI) group and a non-MCI group based on results from the Korean Dementia Screening Questionnaire. A single-session CEFP was conducted over 50 min and consisted of four parts: warm-up, low intensity interval circulation dance exercises, moderate intensity resistance exercises using elastic bands, and cool-down. Serum BDNF levels were measured by ELISA and short-term memory determined by forward digit/word span test was assessed before and after CEFP. After CEFP, forward digit/word span test scores and BDNF levels increased to median 119.2%/115.1% and 118.7%, respectively. After CEFP, the MCI and non-MCI groups produced higher forward digit span test scores (from 6.7 ± 1.5 to 7.5 ± 1.4 points, p = 0.023 and from 6.2 ± 2.0 to 7.0 ± 2.1 points, P=0.011, respectively). After CEFP, forward word span scores and BDNF levels increased (from 3.5 ± 1.7 to 4.6 ± 1.8 points, p = 0.029 and from 610.8 ± 221.1 to 757.9 ± 267.9 pg/ml, p = 0.017, respectively) in non-MCI group only. No group differences were observed between change in short-term memory and change in BDNF. Short-term memory and BDNF levels after CEFP were found to be negatively correlated with age, but pre- to post-intervention changes in short-term memory and BDNF were not. The present study shows that a single, 50-minute CEFP improved short-term memory and increased serum BDNF levels in healthy middle-aged women, especially those without MCI. Key points A single 50-minute CEFP comprised 5 minutes of general warm up and mat stretching, 20 minutes of low intensity activities with 8 dance exercises (RPE 11-12), another 20 minutes of moderate intensity activities including 8 resistance exercises using elastic bands ((RPE 13-15), and finally a 5-minute general cool down with yoga. Both MCI and non-MCI groups produced higher forward digit span test scores and had higher serum BDNF levels after CEFP but forward word span scores were increased only in non-MCI. A single 50-minute brain fitness program improved short-term memory and increased serum BDNF levels in healthy middle-aged women, especially those without MCI. PMID:29535584

The acute toxicity of brief exposures to HF, HCl, NO2 and HCN singly and in combination with CO.

DOT National Transportation Integrated Search

1971-11-01

Experiments were conducted with animals to determine the toxic effect of short-term exposures to some of the products produced in aircraft fires; the products were tested both singly and in combination with carbon monoxide. These studies show the tox...

Roles and Responsibilities--Single College Orientation.

ERIC Educational Resources Information Center

Fonte, Richard

Austin Community College (ACC) is undergoing reorganization in an attempt to create a "single college" organizational structure to replace its current "campus with five competing colleges" model. By doing so, ACC hopes to create an atmosphere in which short and long range planning efforts are aimed at the overall good of the…

Transient receptor potential cation channel A1 (TRPA1) mediates changes in heart rate variability following a single exposure to acrolein in mice

EPA Science Inventory

The data show that a single exposure to acrolein causes autonomic imbalance in mice through the TRPA1 sensor and subsequent cardiac dysfunction. Human and animal studies have shown that short-term air pollution exposure causes...

The Influence of Contextual Change on Remembering in Short-Term Memory. Final Report.

ERIC Educational Resources Information Center

Falkenberg, Philippe R.

If the contextual similarity between learning and recall within a single trial in a short-term memory (STM) paradigm is varied, recall varies proportionately. This context effect was demonstrated using variations of the Peterson-Peterson (1959) paradigm for both aurally and visually presented material, verbal and arithmetic context, and within and…

Expectation values of twist fields and universal entanglement saturation of the free massive boson

NASA Astrophysics Data System (ADS)

Blondeau-Fournier, Olivier; Doyon, Benjamin

2017-07-01

The evaluation of vacuum expectation values (VEVs) in massive integrable quantum field theory (QFT) is a nontrivial renormalization-group ‘connection problem’—relating large and short distance asymptotics—and is in general unsolved. This is particularly relevant in the context of entanglement entropy, where VEVs of branch-point twist fields give universal saturation predictions. We propose a new method to compute VEVs of twist fields associated to continuous symmetries in QFT. The method is based on a differential equation in the continuous symmetry parameter, and gives VEVs as infinite form-factor series which truncate at two-particle level in free QFT. We verify the method by studying U(1) twist fields in free models, which are simply related to the branch-point twist fields. We provide the first exact formulae for the VEVs of such fields in the massive uncompactified free boson model, checking against an independent calculation based on angular quantization. We show that logarithmic terms, overlooked in the original work of Callan and Wilczek (1994 Phys. Lett. B 333 55-61), appear both in the massless and in the massive situations. This implies that, in agreement with numerical form-factor observations by Bianchini and Castro-Alvaredo (2016 Nucl. Phys. B 913 879-911), the standard power-law short-distance behavior is corrected by a logarithmic factor. We discuss how this gives universal formulae for the saturation of entanglement entropy of a single interval in near-critical harmonic chains, including loglog corrections.

The Spot Variability and Related Brightness variations of the Solar Type PreContact W UMa Binary System V1001 Cas

NASA Astrophysics Data System (ADS)

Samec, Ronald George; Koenke, Sam S.; Faulkner, Danny R.

2015-08-01

A new classification of eclipsing binary has emerged, Pre Contact WUMa Binaries (PCWB’s, Samec et al. 2012). These solar-type systems are usually detached or semidetached with one or both components under filling their critical Roche lobes. They usually have EA or EB-type light curves (unequal eclipse depths, indicating components with substantially different temperatures). The accepted scenario for these W UMa binaries is that they are undergoing steady but slow angular momentum losses due to magnetic braking as stellar winds blow radially away on stiff bipolar field lines. These binaries are believed to come into stable contact and eventually coalesce into blue straggler type, single, fast rotating A-type stars (Guinan and Bradstreet,1988). High precision 2012 and 2009 light curves are compared for the very short period (~0.43d) Precontact W UMa Binary (PCWB), V1001 Cassiopeia. This is the shortest period PCWB found so far. Its short period, similar to the majority of W UMa’s, in contrast to its distinct Algol-type light curve, make it a very rare and interesting system. Our solutions of light curves separated by some three years give approximately the same physical parameters. However the spots radically change, in temperature, area and position causing a distinctive variation in the shape of the light curves. We conclude that spots are very active on this solar type dwarf system and that it may mimic its larger cousins, the RS CVn binaries.

Integrating Direct and Inquiry-Based Instruction in the Teaching of Critical Thinking: An Intervention Study

ERIC Educational Resources Information Center

Ku, Kelly Y. L.; Ho, Irene T.; Hau, Kit-Tai; Lai, Eva C. M.

2014-01-01

Critical thinking is a unifying goal of modern education. While past research has mostly examined the efficacy of a single instructional approach to teaching critical thinking, recent literature has begun discussing mixed teaching approaches. The present study examines three modes of instruction, featuring the direct instruction approach and the…

Photon Antibunching in the Fluorescence of a Single Dye Molecule Trapped in a Solid

DTIC Science & Technology

1992-06-08

number) FIELD GROUP SUB-GROUP single-molecule spectroscopy in solids, photon antibunching, quantum-optics, nonclassical effects pentacene in p-terphenyl...emitted by an optically pumped single molecule of pentacene In a p-terphenyl host has been Investigated at short times. The correlation function...excitation tcclnique, certain individual pentacene impurity molecules in a p-terphenyl crystal 11 were observed to spectrally diffuse, i.e. their absorption

Critical layer thickness in In/sub 0. 2/Ga/sub 0. 8/As/GaAs single strained quantum well structures

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

Fritz, I.J.; Gourley, P.L.; Dawson, L.R.

1987-09-28

We report accurate determination of the critical layer thickness (CLT) for single strained-layer epitaxy in the InGaAs/GaAs system. Our samples were molecular beam epitaxially grown, selectively doped, single quantum well structures comprising a strained In/sub 0.2/Ga/sub 0.8/As layer imbedded in GaAs. We determined the CLT by two sensitive techniques: Hall-effect measurements at 77 K and photoluminescence microscopy. Both techniques indicate a CLT of about 20 nm. This value is close to that determined previously (--15 nm) for comparable strained-layer superlattices, but considerably less than the value of --45 nm suggested by recent x-ray rocking-curve measurements. We show by a simplemore » calculation that photoluminescence microscopy is more than two orders of magnitude more sensitive to dislocations than x-ray diffraction. Our results re-emphasize the necessity of using high-sensitivity techniques for accurate determination of critical layer thicknesses.« less

Base line estimation using single passes of laser data

NASA Technical Reports Server (NTRS)

Dunn, P. J.; Torrence, M.; Smith, D. E.; Kolenkiewicz, R.

1979-01-01

The laser data of the GEOS 3 satellite passes observed by four stations at Greenbelt (Maryland), Bermuda, Grand Turk Island (Bahamas) and Patrick Air Force Base (Florida), were employed to determine precise interstation base lines and relative heights in short orbital arcs of no more than 12-min duration. No more than five arcs of data are required to define the interstation base lines to 30-cm precision. Base lines running parallel to the orbital motion can be defined to submeter precision from a single short arc of data. Combining arcs of different orbital geometry in a common adjustment of two or more stations relative to the base station helps to compensate for weak base line definition in any single arc. This technique can be used for tracking such spacecraft as Lageos, a high-altitude retroreflector-carrying satellite designed for precise laser ranging studies.

Vibration energy harvester with sustainable power based on a single-crystal piezoelectric cantilever array.

PubMed

Kim, Moonkeun; Lee, Sang-Kyun; Ham, Yong-Hyun; Yang, Yil Suk; Kwon, Jong-Kee; Kwon, Kwang-Ho

2012-08-01

We designed and fabricated a bimorph cantilever array for sustainable power with an integrated Cu proof mass to obtain additional power and current. We fabricated a cantilever system using single-crystal piezoelectric material and compared the calculations for single and arrayed cantilevers to those obtained experimentally. The vibration energy harvester had resonant frequencies of 60.4 and 63.2 Hz for short and open circuits, respectively. The damping ratio and quality factor of the cantilever device were 0.012 and 41.66, respectively. The resonant frequency at maximum average power was 60.8 Hz. The current and highest average power of the harvester array were found to be 0.728 mA and 1.61 mW, respectively. The sustainable maximum power was obtained after slightly shifting the short-circuit frequency. In order to improve the current and power using an array of cantilevers, we also performed energy conversion experiments.

A short note on the mean exit time of the Brownian motion

NASA Astrophysics Data System (ADS)

Cadeddu, Lucio; Farina, Maria Antonietta

We investigate the functional Ω↦ℰ(Ω) where Ω runs through the set of compact domains of fixed volume v in any Riemannian manifold (M,g) and where ℰ(Ω) is the mean exit time from Ω of the Brownian motion. We give an alternative analytical proof of a well-known fact on its critical points proved by McDonald: the critical points of ℰ(Ω) are harmonic domains.

New perspectives in ocean acidification research: editor's introduction to the special feature on ocean acidification.

PubMed

Munday, Philip L

2017-09-01

Ocean acidification, caused by the uptake of additional carbon dioxide (CO 2 ) from the atmosphere, will have far-reaching impacts on marine ecosystems (Gattuso & Hansson 2011 Ocean acidification Oxford University Press). The predicted changes in ocean chemistry will affect whole biological communities and will occur within the context of global warming and other anthropogenic stressors; yet much of the biological research conducted to date has tested the short-term responses of single species to ocean acidification conditions alone. While an important starting point, these studies may have limited predictive power because they do not account for possible interactive effects of multiple climate change drivers or for ecological interactions with other species. Furthermore, few studies have considered variation in responses among populations or the evolutionary potential within populations. Therefore, our knowledge about the potential for marine organisms to adapt to ocean acidification is extremely limited. In 2015, two of the pioneers in the field, Ulf Riebesell and Jean-Pierre Gattuso, noted that to move forward as a field of study, future research needed to address critical knowledge gaps in three major areas: (i) multiple environmental drivers, (ii) ecological interactions and (iii) acclimation and adaptation (Riebesell and Gattuso 2015 Nat. Clim. Change 5 , 12-14 (doi:10.1038/nclimate2456)). In May 2016, more than 350 researchers, students and stakeholders met at the 4th International Symposium on the Ocean in a High-CO 2 World in Hobart, Tasmania, to discuss the latest advances in understanding ocean acidification and its biological consequences. Many of the papers presented at the symposium reflected this shift in focus from short-term, single species and single stressor experiments towards multi-stressor and multispecies experiments that address knowledge gaps about the ecological impacts of ocean acidification on marine communities. The nine papers in this Special Feature are from authors who attended the symposium and address cutting-edge questions and emerging topics in ocean acidification research, across the taxonomic spectrum from plankton to top predators. They cover the three streams of research identified as crucial to understanding the biological impacts of ocean acidification: (i) the relationship with other environmental drivers, (ii) the effects on ecological process and species interactions, and (iii) the role that individual variation, phenotypic plasticity and adaptation will have in shaping the impacts of ocean acidification and warming on marine ecosystems. © 2017 The Author(s).

Effect of load eccentricity on the buckling of thin-walled laminated C-columns

NASA Astrophysics Data System (ADS)

Wysmulski, Pawel; Teter, Andrzej; Debski, Hubert

2018-01-01

The study investigates the behaviour of short, thin-walled laminated C-columns under eccentric compression. The tested columns are simple-supported. The effect of load inaccuracy on the critical and post-critical (local buckling) states is examined. A numerical analysis by the finite element method and experimental tests on a test stand are performed. The samples were produced from a carbon-epoxy prepreg by the autoclave technique. The experimental tests rest on the assumption that compressive loads are 1.5 higher than the theoretical critical force. Numerical modelling is performed using the commercial software package ABAQUS®. The critical load is determined by solving an eigen problem using the Subspace algorithm. The experimental critical loads are determined based on post-buckling paths. The numerical and experimental results show high agreement, thus demonstrating a significant effect of load inaccuracy on the critical load corresponding to the column's local buckling.

Preferential growth of short aligned, metallic-rich single-walled carbon nanotubes from perpendicular layered double hydroxide film.

PubMed

Zhao, Meng-Qiang; Tian, Gui-Li; Zhang, Qiang; Huang, Jia-Qi; Nie, Jing-Qi; Wei, Fei

2012-04-07

Direct bulk growth of single-walled carbon nanotubes (SWCNTs) with required properties, such as diameter, length, and chirality, is the first step to realize their advanced applications in electrical and optical devices, transparent conductive films, and high-performance field-effect transistors. Preferential growth of short aligned, metallic-rich SWCNTs is a great challenge to the carbon nanotube community. We report the bulk preferential growth of short aligned SWCNTs from perpendicular Mo-containing FeMgAl layered double hydroxide (LDH) film by a facile thermal chemical vapor deposition with CH(4) as carbon source. The growth of the short aligned SWCNTs showed a decreased growth velocity with an initial value of 1.9 nm s(-1). Such a low growth velocity made it possible to get aligned SWCNTs shorter than 1 μm with a growth duration less than 15 min. Raman spectra with different excitation wavelengths indicated that the as-grown short aligned SWCNTs showed high selectivity of metallic SWCNTs. Various kinds of materials, such as mica, quartz, Cu foil, and carbon fiber, can serve as the substrates for the growth of perpendicular FeMoMgAl LDH films and also the growth of the short aligned SWCNTs subsequently. These findings highlight the easy route for bulk preferential growth of aligned metallic-rich SWCNTs with well defined length for further bulk characterization and applications. This journal is © The Royal Society of Chemistry 2012

Dead-time optimized time-correlated photon counting instrument with synchronized, independent timing channels

NASA Astrophysics Data System (ADS)

Wahl, Michael; Rahn, Hans-Jürgen; Gregor, Ingo; Erdmann, Rainer; Enderlein, Jörg

2007-03-01

Time-correlated single photon counting is a powerful method for sensitive time-resolved fluorescence measurements down to the single molecule level. The method is based on the precisely timed registration of single photons of a fluorescence signal. Historically, its primary goal was the determination of fluorescence lifetimes upon optical excitation by a short light pulse. This goal is still important today and therefore has a strong influence on instrument design. However, modifications and extensions of the early designs allow for the recovery of much more information from the detected photons and enable entirely new applications. Here, we present a new instrument that captures single photon events on multiple synchronized channels with picosecond resolution and over virtually unlimited time spans. This is achieved by means of crystal-locked time digitizers with high resolution and very short dead time. Subsequent event processing in programmable logic permits classical histogramming as well as time tagging of individual photons and their streaming to the host computer. Through the latter, any algorithms and methods for the analysis of fluorescence dynamics can be implemented either in real time or offline. Instrument test results from single molecule applications will be presented.

Molecular dynamics simulation on the elastoplastic properties of copper nanowire under torsion

NASA Astrophysics Data System (ADS)

Yang, Yong; Li, Ying; Yang, Zailin; Zhang, Guowei; Wang, Xizhi; Liu, Jin

2018-02-01

Influences of different factors on the torsion properties of single crystal copper nanowire are studied by molecular dynamics method. The length, torsional rate, and temperature of the nanowire are discussed at the elastic-plastic critical point. According to the average potential energy curve and shear stress curve, the elastic-plastic critical angle is determined. Also, the dislocation at elastoplastic critical points is analyzed. The simulation results show that the single crystal copper nanowire can be strengthened by lengthening the model, decreasing the torsional rate, and lowering the temperature. Moreover, atoms move violently and dislocation is more likely to occur with a higher temperature. This work mainly describes the mechanical behavior of the model under different states.

Quantum Phase Transitions in the Bose Hubbard Model and in a Bose-Fermi Mixture

NASA Astrophysics Data System (ADS)

Duchon, Eric Nicholas

Ultracold atomic gases may be the ultimate quantum simulator. These isolated systems have the lowest temperatures in the observable universe, and their properties and interactions can be precisely and accurately tuned across a full spectrum of behaviors, from few-body physics to highly-correlated many-body effects. The ability to impose potentials on and tune interactions within ultracold gases to mimic complex systems mean they could become a theorist's playground. One of their great strengths, however, is also one of the largest obstacles to this dream: isolation. This thesis touches on both of these themes. First, methods to characterize phases and quantum critical points, and to construct finite temperature phase diagrams using experimentally accessible observables in the Bose Hubbard model are discussed. Then, the transition from a weakly to a strongly interacting Bose-Fermi mixture in the continuum is analyzed using zero temperature numerical techniques. Real materials can be emulated by ultracold atomic gases loaded into optical lattice potentials. We discuss the characteristics of a single boson species trapped in an optical lattice (described by the Bose Hubbard model) and the hallmarks of the quantum critical region that separates the superfluid and the Mott insulator ground states. We propose a method to map the quantum critical region using the single, experimentally accessible, local quantity R, the ratio of compressibility to local number fluctuations. The procedure to map a phase diagram with R is easily generalized to inhomogeneous systems and generic many-body Hamiltonians. We illustrate it here using quantum Monte Carlo simulations of the 2D Bose Hubbard model. Secondly, we investigate the transition from a degenerate Fermi gas weakly coupled to a Bose Einstein condensate to the strong coupling limit of composite boson-fermion molecules. We propose a variational wave function to investigate the ground state properties of such a Bose-Fermi mixture with equal population, as a function of increasing attraction between bosons and fermions. The variational wave function captures the weak and the strong coupling limits and at intermediate coupling we make two predictions using zero temperature quantum Monte Carlo methods: (I) a complete destruction of the atomic Fermi surface and emergence of a molecular Fermi sea that coexists with a remnant of the Bose-Einstein condensate, and (II) evidence for enhanced short-ranged fermion-fermion correlations mediated by bosons.

GEOPHYSICS, ASTRONOMY AND ASTROPHYSICS: Numerical method of studying nonlinear interactions between long waves and multiple short waves

NASA Astrophysics Data System (ADS)

Xie, Tao; Kuang, Hai-Lan; William, Perrie; Zou, Guang-Hui; Nan, Cheng-Feng; He, Chao; Shen, Tao; Chen, Wei

2009-07-01

Although the nonlinear interactions between a single short gravity wave and a long wave can be solved analytically, the solution is less tractable in more general cases involving multiple short waves. In this work we present a numerical method of studying nonlinear interactions between a long wave and multiple short harmonic waves in infinitely deep water. Specifically, this method is applied to the calculation of the temporal and spatial evolutions of the surface elevations in which a given long wave interacts with several short harmonic waves. Another important application of our method is to quantitatively analyse the nonlinear interactions between an arbitrary short wave train and another short wave train. From simulation results, we obtain that the mechanism for the nonlinear interactions between one short wave train and another short wave train (expressed as wave train 2) leads to the energy focusing of the other short wave train (expressed as wave train 3). This mechanism occurs on wave components with a narrow frequency bandwidth, whose frequencies are near that of wave train 3.

Three-dimensional single-mode nonlinear ablative Rayleigh-Taylor instability

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

Yan, R.; Betti, R.; Sanz, J.

The nonlinear evolution of the single-mode ablative Rayleigh-Taylor instability is studied in three dimensions. As the mode wavelength approaches the cutoff of the linear spectrum (short-wavelength modes), it is found that the three-dimensional (3D) terminal bubble velocity greatly exceeds both the two-dimensional (2D) value and the classical 3D bubble velocity. Unlike in 2D, the 3D short-wavelength bubble velocity does not saturate. The growing 3D bubble acceleration is driven by the unbounded accumulation of vorticity inside the bubble. As a result, the vorticity is transferred by mass ablation from the Rayleigh-Taylor spikes to the ablated plasma filling the bubble volume.

Start-to-end simulation of single-particle imaging using ultra-short pulses at the European X-ray Free-Electron Laser

PubMed Central

Buzmakov, Alexey; Jurek, Zoltan; Loh, Ne-Te Duane; Samoylova, Liubov; Santra, Robin; Schneidmiller, Evgeny A.; Tschentscher, Thomas; Yakubov, Sergey; Yoon, Chun Hong; Yurkov, Michael V.; Ziaja-Motyka, Beata; Mancuso, Adrian P.

2017-01-01

Single-particle imaging with X-ray free-electron lasers (XFELs) has the potential to provide structural information at atomic resolution for non-crystalline biomolecules. This potential exists because ultra-short intense pulses can produce interpretable diffraction data notwithstanding radiation damage. This paper explores the impact of pulse duration on the interpretability of diffraction data using comprehensive and realistic simulations of an imaging experiment at the European X-ray Free-Electron Laser. It is found that the optimal pulse duration for molecules with a few thousand atoms at 5 keV lies between 3 and 9 fs. PMID:28989713

Testing of TAMU3: a Nb 3Sn Block–Coil Dipole with Stress Management

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

McIntyre, Peter

The Accelerator Research Lab (ARL) at Texas A&M has recently concluded the construction and testing of a superconducting block-coil dipole TAMU3. TAMU3 reached 85% of the resistive-onset short sample critical current (0.1 μV/cm criterion) that was measured on extracted strands at the National High Magnetic Field Lab. Peak magnet current was 6603 amps, and all with quenches originated in the vicinity of the hard-way chicane near the exit lead of the TAMU3c inner winding. Leading up to the testing we discovered that we had made two grievous mistakes in the fabrication (we mistakenly used the wrong superconducting wire for themore » cables of the inner windings) and the heat treatment (we used a heat treatment that was too hot and too long). We extracted strands from the leads of the inner and outer windings, and colleagues at NHMFL performed short-sample measurements upon them. The NHMFL measurements indicated RRR ~ 2-5, which gives very little stability against microquenches. The short-sample tests of the extracted strands exhibited a long resistive transition, in which there was a current I sc(B) beyond which it became resistive, then a higher current In(B) at which it went fully normal. Using the I sc(B) data we predicted a short-sample limit for the revised load line of TAMU3 of 7700 A (9 T) – a disappointing reduction from the 14 T objective. On those unhappy notes we undertook the testing of the dipole. The first quench occurred at 5695 A, and the dipole trained thereafter to a maximum quench current of 6600 A (7.6 T), 85% of the compromised short-sample limit. All quenches occurred at a single location, in the region of the S-bend transition and outer lead of one inner winding. Data was collected from stress transducers on the outer windings to evaluate stress management, and on the coil ends to evaluate capture of axial forces by staticfriction lock. The low field reached prevented us from extending those tests to the stress levels where they would have become most interesting, but the designed stress management appeared to be working at the level tested.« less

Impact of Multiple Complex Plaques on Short-and Long-Term Clinical in Patients Presenting with ST-Segment Elevation Myocardial Infarction (From the Harmonizing Outcomes with Revascularization and Stents in Acute Myocardial Infarction [HORIZONS-AMI] Trial)

PubMed Central

Keeley, Ellen C.; Mehran, Roxana; Brener, Sorin J.; Witzenbichler, Bernhard; Guagliumi, Giulio; Dudek, Dariusz; Kornowski, Ran; Dressler, Ovidiu; Fahy, Martin; Xu, Ke; Grines, Cindy L.; Stone, Gregg W.

2014-01-01

It is not known whether the extent and severity of non-culprit coronary lesions correlate with outcomes in patients with STEMI referred for primary PCI. We sought to quantify complex plaques in ST-segment elevation myocardial infarction (STEMI) patients referred for primary percutaneous coronary intervention (PCI) and to determine their effect on short- and long-term clinical outcomes by examining the core laboratory database for plaque analysis from the HORIZONS-AMI study. Baseline demographic, angiographic, and procedural details were compared between patients with single vs. multiple complex plaques undergoing single vessel PCI. Multivariable analysis was performed for predictors of long-term major adverse cardiac events (MACE), a combined end point of death, reinfarction, ischemic target vessel revascularization, or stroke, and for death alone. Single vessel PCI was performed in 3,137 patients (87%): 2,174 (69%) had multiple complex plaques and 963 (31%) had a single complex plaque. Compared to those with a single complex plaque, patients with multiple complex plaques were older (p<0.0001) and had more comorbidities. The presence of multiple complex plaques was an independent predictor of 3-year MACE (hazard ratio [HR]: 1.58; 95% confidence interval [CI]: 1.26–1.98, p<0.0001), and death alone (HR: 1.68; 95% CI: 1.05–2.70, p=0.03). In conclusion, multiple complex plaques are present in the majority of STEMI patients undergoing primary PCI and their presence is an independent predictor of short- and long-term MACE, including death. (Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction [HORIZONS-AMI]; NCT00433966) PMID:24703369

Critical thinking in nursing: an integrated review.

PubMed

Brunt, Barbara A

2005-01-01

Critical thinking skills are essential to function in today's complex health care environment and to ensure continuing competence for the future. This article provides a review of various definitions and research studies related to critical thinking. Educators and researchers need to clearly define critical thinking, because there has been wide variation in definitions and descriptions of critical thinking. Research studies have shown inconsistent findings, and many have used a one-group pretest-posttest design over a single course or during the length of a nursing program. Studies have not shown an association between critical thinking and competence; rigorous research studies are needed to understand the process of critical thinking.

Locality of Temperature

NASA Astrophysics Data System (ADS)

Kliesch, M.; Gogolin, C.; Kastoryano, M. J.; Riera, A.; Eisert, J.

2014-07-01

This work is concerned with thermal quantum states of Hamiltonians on spin- and fermionic-lattice systems with short-range interactions. We provide results leading to a local definition of temperature, thereby extending the notion of "intensivity of temperature" to interacting quantum models. More precisely, we derive a perturbation formula for thermal states. The influence of the perturbation is exactly given in terms of a generalized covariance. For this covariance, we prove exponential clustering of correlations above a universal critical temperature that upper bounds physical critical temperatures such as the Curie temperature. As a corollary, we obtain that above the critical temperature, thermal states are stable against distant Hamiltonian perturbations. Moreover, our results imply that above the critical temperature, local expectation values can be approximated efficiently in the error and the system size.

The extra mile: Ungulate migration distance alters the use of seasonal range and exposure to anthropogenic risk

USGS Publications Warehouse

Sawyer, Hall; Middleton, Arthur D.; Hayes, Matthew M.; Kauffman, Matthew J.; Monteith, Kevin L.

2016-01-01

Partial migration occurs across a variety of taxa and has important ecological and evolutionary consequences. Among ungulates, studies of partially migratory populations have allowed researchers to compare and contrast performance metrics of migrants versus residents and examine how environmental factors influence the relative abundance of each. Such studies tend to characterize animals discretely as either migratory or resident, but we suggest that variable migration distances within migratory herds are an important and overlooked form of population structure, with potential consequences for animal fitness. We examined whether the variation in individual migration distances (20–264 km) within a single wintering population of mule deer (Odocoileus hemionus) was associated with several critical behavioral attributes of migration, including timing of migration, time allocation to seasonal ranges, and exposure to anthropogenic mortality risks. Both the timing of migration and the amount of time animals allocated to seasonal ranges varied with migration distance. Animals migrating long distances (150–250 km) initiated spring migration more than three weeks before than those migrating moderate (50–150 km) or short distances (<50 km). Across an entire year, long-distance migrants spent approximately 100 more days migrating compared to moderate- and short-distance migrants. Relatedly, winter residency of long-distance migrants was 71 d fewer than for animals migrating shorter distances. Exposure to anthropogenic mortality factors, including highways and fences, was high for long-distance migrants, whereas vulnerability to harvest was high for short- and moderate-distance migrants. By reducing the amount of time that animals spend on winter range, long-distance migration may alleviate intraspecific competition for limited forage and effectively increase carrying capacity. Clear differences in winter residency, migration duration, and risk of anthropogenic mortality among short-, moderate-, and long-distance migrants suggest fitness trade-offs may exist among migratory segments of the population. Future studies of partial migration may benefit from expanding comparisons of residents and migrants, to consider how variable migration distances of migrants may influence the costs and benefits of migration.

Prediction of the elastic modulus of wood flour/kenaf fibre/polypropylene hybrid composites

Treesearch

Jamal Mirbagheri; Mehdi Tajvidi; Ismaeil Ghasemi; John C. Hermanson

2007-01-01

The prediction of the elastic modulus of short natural fibre hybrid composites has been investigated by using the properties of the pure composites through the rule of hybrid mixtures (RoHM) equation. In this equation, a hybrid natural fibre composite assumed as a system consisting of two separate single systems, namely particle/polymer and short-fibre/polymer systems...

How to Say No: Single- and Dual-Process Theories of Short-Term Recognition Tested on Negative Probes

ERIC Educational Resources Information Center

Oberauer, Klaus

2008-01-01

Three experiments with short-term recognition tasks are reported. In Experiments 1 and 2, participants decided whether a probe matched a list item specified by its spatial location. Items presented at study in a different location (intrusion probes) had to be rejected. Serial position curves of positive, new, and intrusion probes over the probed…

Short-Read Sequencing for Genomic Analysis of the Brown Rot Fungus Fibroporia radiculosa

Treesearch

J. D. Tang; A. D. Perkins; T. S. Sonstegard; S. G. Schroeder; S. C. Burgess; S. V. Diehl

2012-01-01

The feasibility of short-read sequencing for genomic analysis was demonstrated for Fibroporia radiculosa, a copper-tolerant fungus that causes brown rot decay of wood. The effect of read quality on genomic assembly was assessed by filtering Illumina GAIIx reads from a single run of a paired-end library (75-nucleotide read length and 300-bp fragment...

Short-Term Effectiveness of Psychotherapy Treatments Delivered at a University Counselling Service

ERIC Educational Resources Information Center

Monti, Fiorella; Tonetti, Lorenzo; Ricci Bitti, Pio Enrico

2016-01-01

This work aimed to evaluate the short-term effectiveness of psychotherapy delivered at the counselling service of the University of Bologna (Italy), by means of a single group longitudinal study including a 6-months follow-up. To this end, sixty-six students completed the 6-months follow-up and filled in the Symptom Questionnaire (SQ) three times,…

High affinity γPNA sandwich hybridization assay for rapid detection of short nucleic acid targets with single mismatch discrimination.

PubMed

Goldman, Johnathan M; Zhang, Li Ang; Manna, Arunava; Armitage, Bruce A; Ly, Danith H; Schneider, James W

2013-07-08

Hybridization analysis of short DNA and RNA targets presents many challenges for detection. The commonly employed sandwich hybridization approach cannot be implemented for these short targets due to insufficient probe-target binding strengths for unmodified DNA probes. Here, we present a method capable of rapid and stable sandwich hybridization detection for 22 nucleotide DNA and RNA targets. Stable hybridization is achieved using an n-alkylated, polyethylene glycol γ-carbon modified peptide nucleic acid (γPNA) amphiphile. The γPNA's exceptionally high affinity enables stable hybridization of a second DNA-based probe to the remaining bases of the short target. Upon hybridization of both probes, an electrophoretic mobility shift is measured via interaction of the n-alkane modification on the γPNA with capillary electrophoresis running buffer containing nonionic surfactant micelles. We find that sandwich hybridization of both probes is stable under multiple binding configurations and demonstrate single base mismatch discrimination. The binding strength of both probes is also stabilized via coaxial stacking on adjacent hybridization to targets. We conclude with a discussion on the implementation of the proposed sandwich hybridization assay as a high-throughput microRNA detection method.

76 FR 70206 - Self-Regulatory Organizations; ICE Clear Credit LLC; Notice of Filing of Proposed Rule Change to...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-10

... highly correlated relationship between long-short positions in CDS Indices and the underlying CDS Single... currently clear CDS Single Names for customer-related transactions. Accordingly, currently, there are no customer-related positions that would qualify for portfolio margining treatment. ICC does not believe that...

Short communication: Relationship of call rate and accuracy of single nucleotide polymorphism genotypes in dairy cattle

USDA-ARS?s Scientific Manuscript database

Call rate has been used as a measure of quality on both a single nucleotide polymorphism (SNP) and animal basis since SNP genotypes were first used in genomic evaluation of dairy cattle. The genotyping laboratories perform initial quality control screening and genotypes that fail are usually exclude...

Eliciting Students' Understanding of a Local Socioscientific Issue through the Use of Critical Response Pedagogies

ERIC Educational Resources Information Center

Karahan, Engin; Andzenge, Senenge T.; Roehrig, Gillian

2017-01-01

This study introduces a critical response pedagogy (CRP), an arts-based critical technique to facilitate meaningful dialogue in focus group settings, to secondary school science education students to engage them in discussion about sediment and chemical load in their local river basin community. Using a holistic single case design, twenty-two 11th…

Unidirectional signal propagation in primary neurons micropatterned at a single-cell resolution

NASA Astrophysics Data System (ADS)

Yamamoto, H.; Matsumura, R.; Takaoki, H.; Katsurabayashi, S.; Hirano-Iwata, A.; Niwano, M.

2016-07-01

The structure and connectivity of cultured neuronal networks can be controlled by using micropatterned surfaces. Here, we demonstrate that the direction of signal propagation can be precisely controlled at a single-cell resolution by growing primary neurons on micropatterns. To achieve this, we first examined the process by which axons develop and how synapses form in micropatterned primary neurons using immunocytochemistry. By aligning asymmetric micropatterns with a marginal gap, it was possible to pattern primary neurons with a directed polarization axis at the single-cell level. We then examined how synapses develop on micropatterned hippocampal neurons. Three types of micropatterns with different numbers of short paths for dendrite growth were compared. A normal development in synapse density was observed when micropatterns with three or more short paths were used. Finally, we performed double patch clamp recordings on micropatterned neurons to confirm that these synapses are indeed functional, and that the neuronal signal is transmitted unidirectionally in the intended orientation. This work provides a practical guideline for patterning single neurons to design functional neuronal networks in vitro with the direction of signal propagation being controlled.

Single-Site Nissen Fundoplication Versus Laparoscopic Nissen Fundoplication

PubMed Central

Sharp, Nicole E.; Vassaur, John

2014-01-01

Background: Advances in minimally invasive surgery have led to the emergence of single-incision laparoscopic surgery (SILS). The purpose of this study is to assess the feasibility of SILS Nissen fundoplication and compare its outcomes with traditional laparoscopic Nissen fundoplication. Methods: This is a retrospective study of 33 patients who underwent Nissen fundoplication between January 2009 and September 2010. Results: There were 15 SILS and 18 traditional laparoscopic Nissen fundoplication procedures performed. The mean operative time was 129 and 182 minutes in the traditional laparoscopic and single-incision groups, respectively (P = .019). There were no conversions in the traditional laparoscopic group, whereas 6 of the 15 patients in the SILS group required conversion by insertion of 2 to 4 additional ports (P = .0004). At short-term follow-up, recurrence rates were similar between both groups. To date, there have been no reoperations. Conclusions: SILS Nissen fundoplication is both safe and feasible. Short-term outcomes are comparable with standard laparoscopic Nissen fundoplication. Challenges related to the single-incision Nissen fundoplication include overcoming the lengthy learning curve and decreasing the need for additional trocars. PMID:25392613

Porrocaecum parvum n. sp. and P. reticulatum (Linstow, 1899) (Nematoda: Ascaridoidea) from birds in China.

PubMed

Li, Liang; Guo, Yan-Ning; Zhang, Lu-Ping

2015-10-01

Porrocaecum parvum n. sp. is described from the grey-faced buzzard Butastur indicus (Gmelin) (Accipitriformes: Accipitridae) in China. The new species differs from its congeners in having well-developed cervical alae, small interlabia and very short intestinal caecum (0.34 mm long, representing 11.9% of oesophageal length) and in the number and arrangement of the caudal papillae (29 pairs in total, arranged as follows: 21 pairs precloacal, single double pair paracloacal and seven pairs postcloacal) and in the morphology of the male tail. In addition, Porrocaecum reticulatum (Linstow, 1899), collected from the purple heron Ardea purpurea L., the grey heron A. cinerea L. and the little egret Egretta garzetta (L.) (Pelecaniformes: Ardeidae) in China, was also studied using light and, for the first time, scanning electron microscopy. Previously unreported and erroneous morphological features of taxonomic significance are revealed, including the presence of narrow cervical alae, single pair of small, submedial pores and single, short medial ditch on each lip, interlabia with very pointed anterior prolongation, single medio-ventral precloacal papilla on anterior cloacal lip and double paracloacal papillae slightly posterior to cloaca.

Short-term and long-term effects of protein kinase C on the trafficking and stability of human organic anion transporter 3

PubMed Central

Zhang, Qiang; Suh, Wonmo; Pan, Zui; You, Guofeng

2012-01-01

Human organic anion transporter 3 (hOAT3) belongs to a family of organic anion transporters that play critical roles in the body disposition of numerous clinically important drugs. Therefore, understanding the regulation of this transporter has profound clinical significance. In the current study, we investigated the short-term and long-term regulation of hOAT3 by protein kinase C (PKC). We showed that short-term activation of PKC by phobol 12-Myristate 13-Acetate (PMA) inhibited hOAT3 activity through accelerating its internalization from cell surface to intracellular recycling endosomes. The colocalization of hOAT3 with EEA1-positive recycling endosomes was demonstrated by immunolocalization with confocal microscopy. Furthermore, we showed that long-term activation of PKC resulted in the enhanced degradation of cell surface hOAT3. The pathways for hOAT3 degradation were further examined using proteasomal and lysosomal inhibitors. Our results showed that both proteasomal inhibitors and the lysosomal inhibitors significantly blocked hOAT3 degradation. These results demonstrate that PKC plays critical roles in the trafficking and the stability of hOAT3. PMID:22773962

Does the mind map learning strategy facilitate information retrieval and critical thinking in medical students?

PubMed

D'Antoni, Anthony V; Zipp, Genevieve Pinto; Olson, Valerie G; Cahill, Terrence F

2010-09-16

A learning strategy underutilized in medical education is mind mapping. Mind maps are multi-sensory tools that may help medical students organize, integrate, and retain information. Recent work suggests that using mind mapping as a note-taking strategy facilitates critical thinking. The purpose of this study was to investigate whether a relationship existed between mind mapping and critical thinking, as measured by the Health Sciences Reasoning Test (HSRT), and whether a relationship existed between mind mapping and recall of domain-based information. In this quasi-experimental study, 131 first-year medical students were randomly assigned to a standard note-taking (SNT) group or mind map (MM) group during orientation. Subjects were given a demographic survey and pre-HSRT. They were then given an unfamiliar text passage, a pre-quiz based upon the passage, and a 30-minute break, during which time subjects in the MM group were given a presentation on mind mapping. After the break, subjects were given the same passage and wrote notes based on their group (SNT or MM) assignment. A post-quiz based upon the passage was administered, followed by a post-HSRT. Differences in mean pre- and post-quiz scores between groups were analyzed using independent samples t-tests, whereas differences in mean pre- and post-HSRT total scores and subscores between groups were analyzed using ANOVA. Mind map depth was assessed using the Mind Map Assessment Rubric (MMAR). There were no significant differences in mean scores on both the pre- and post-quizzes between note-taking groups. And, no significant differences were found between pre- and post-HSRT mean total scores and subscores. Although mind mapping was not found to increase short-term recall of domain-based information or critical thinking compared to SNT, a brief introduction to mind mapping allowed novice MM subjects to perform similarly to SNT subjects. This demonstrates that medical students using mind maps can successfully retrieve information in the short term, and does not put them at a disadvantage compared to SNT students. Future studies should explore longitudinal effects of mind-map proficiency training on both short- and long-term information retrieval and critical thinking.

Agricultural Land Cover from Multitemporal C-Band SAR Data

NASA Astrophysics Data System (ADS)

Skriver, H.

2013-12-01

Henning Skriver DTU Space, Technical University of Denmark Ørsteds Plads, Building 348, DK-2800 Lyngby e-mail: hs@space.dtu.dk Problem description This paper focuses on land cover type from SAR data using high revisit acquisitions, including single and dual polarisation and fully polarimetric data, at C-band. The data set were acquired during an ESA-supported campaign, AgriSAR09, with the Radarsat-2 system. Ground surveys to obtain detailed land cover maps were performed during the campaign. Classification methods using single- and dual-polarisation data, and fully polarimetric data are used with multitemporal data with short revisit time. Results for airborne campaigns have previously been reported in Skriver et al. (2011) and Skriver (2012). In this paper, the short revisit satellite SAR data will be used to assess the trade-off between polarimetric SAR data and data as single or dual polarisation SAR data. This is particularly important in relation to the future GMES Sentinel-1 SAR satellites, where two satellites with a relatively wide swath will ensure a short revisit time globally. Questions dealt with are: which accuracy can we expect from a mission like the Sentinel-1, what is the improvement of using polarimetric SAR compared to single or dual polarisation SAR, and what is the optimum number of acquisitions needed. Methodology The data have sufficient number of looks for the Gaussian assumption to be valid for the backscatter coefficients for the individual polarizations. The classification method used for these data is therefore the standard Bayesian classification method for multivariate Gaussian statistics. For the full-polarimetric cases two classification methods have been applied, the standard ML Wishart classifier, and a method based on a reversible transform of the covariance matrix into backscatter intensities. The following pre-processing steps were performed on both data sets: The scattering matrix data in the form of SLC products were coregistered, converted to covariance matrix format and multilooked to a specific equivalent number of looks. Results The multitemporal data improve significantly the classification results, and single acquisition data cannot provide the necessary classification performance. The multitemporal data are especially important for the single and dual polarization data, but less important for the fully polarimetric data. The satellite data set produces realistic classification results based on about 2000 fields. The best classification results for the single-polarized mode provide classification errors in the mid-twenties. Using the dual-polarized mode reduces the classification error with about 5 percentage points, whereas the polarimetric mode reduces it with about 10 percentage points. These results show, that it will be possible to obtain reasonable results with relatively simple systems with short revisit time. This very important result shows that systems like the Sentinel-1 mission will be able to produce fairly good results for global land cover classification. References Skriver, H. et al., 2011, 'Crop Classification using Short-Revisit Multitemporal SAR Data', IEEE J. Sel. Topics in Appl. Earth Obs. Rem. Sens., vol. 4, pp. 423-431. Skriver, H., 2012, 'Crop classification by multitemporal C- and L-band single- and dual-polarization and fully polarimetric SAR', IEEE Trans. Geosc. Rem. Sens., vol. 50, pp. 2138-2149.

Radiation Requirements and Requirements Flowdown: Single Event Effects (SEEs) and Requirements

NASA Technical Reports Server (NTRS)

LaBel, Kenneth A.

2002-01-01

This short course session provides: (1) an overview of the single particle-induced hazard for space system as they apply in the natural space environment. This shall focus on the implementation of a single event effect hardness assurance (SEEHA) program for systems including system engineering approach and mitigation of effects. (2) The final portion of this session shell provide relevant real-life examples of in-flight performance of systems.

What you need to know about ossification of the posterior longitudinal ligament to optimize cervical spine surgery: A review

PubMed Central

Epstein, Nancy E.

2014-01-01

What are the risks, benefits, alternatives, and pitfalls for operating on cervical ossification of the posterior longitudinal ligament (OPLL)? To successfully diagnose OPLL, it is important to obtain Magnetic Resonance Images (MR). These studies, particularly the T2 weighted images, provide the best soft-tissue documentation of cord/root compression and intrinsic cord abnormalities (e.g. edema vs. myelomalacia) on sagittal, axial, and coronal views. Obtaining Computed Tomographic (CT) scans is also critical as they best demonstrate early OPLL, or hypertrophied posterior longitudinal ligament (HPLL: hypo-isodense with punctate ossification) or classic (frankly ossified) OPLL (hyperdense). Furthermore, CT scans reveal the “single layer” and “double layer” signs indicative of OPLL penetrating the dura. Documenting the full extent of OPLL with both MR and CT dictates whether anterior, posterior, or circumferential surgery is warranted. An adequate cervical lordosis allows for posterior cervical approaches (e.g. lamionplasty, laminectomy/fusion), which may facilitate addressing multiple levels while avoiding the risks of anterior procedures. However, without lordosis and with significant kyphosis, anterior surgery may be indicated. Rarely, this requires single/multilevel anterior cervical diskectomy/fusion (ACDF), as this approach typically fails to address retrovertebral OPLL; single or multilevel corpectomies are usually warranted. In short, successful OPLL surgery relies on careful patient selection (e.g. assess comorbidities), accurate MR/CT documentation of OPLL, and limiting the pros, cons, and complications of these complex procedures by choosing the optimal surgical approach. Performing OPLL surgery requires stringent anesthetic (awake intubation/positioning) and also the following intraoperative monitoring protocols: Somatosensory evoked potentials (SSEP), motor evoked potentials (MEP), and electromyography (EMG). PMID:24843819

Superresolution microscope image reconstruction by spatiotemporal object decomposition and association: application in resolving t-tubule structure in skeletal muscle

PubMed Central

Sun, Mingzhai; Huang, Jiaqing; Bunyak, Filiz; Gumpper, Kristyn; De, Gejing; Sermersheim, Matthew; Liu, George; Lin, Pei-Hui; Palaniappan, Kannappan; Ma, Jianjie

2014-01-01

One key factor that limits resolution of single-molecule superresolution microscopy relates to the localization accuracy of the activated emitters, which is usually deteriorated by two factors. One originates from the background noise due to out-of-focus signals, sample auto-fluorescence, and camera acquisition noise; and the other is due to the low photon count of emitters at a single frame. With fast acquisition rate, the activated emitters can last multiple frames before they transiently switch off or permanently bleach. Effectively incorporating the temporal information of these emitters is critical to improve the spatial resolution. However, majority of the existing reconstruction algorithms locate the emitters frame by frame, discarding or underusing the temporal information. Here we present a new image reconstruction algorithm based on tracklets, short trajectories of the same objects. We improve the localization accuracy by associating the same emitters from multiple frames to form tracklets and by aggregating signals to enhance the signal to noise ratio. We also introduce a weighted mean-shift algorithm (WMS) to automatically detect the number of modes (emitters) in overlapping regions of tracklets so that not only well-separated single emitters but also individual emitters within multi-emitter groups can be identified and tracked. In combination with a maximum likelihood estimator method (MLE), we are able to resolve low to medium density of overlapping emitters with improved localization accuracy. We evaluate the performance of our method with both synthetic and experimental data, and show that the tracklet-based reconstruction is superior in localization accuracy, particularly for weak signals embedded in a strong background. Using this method, for the first time, we resolve the transverse tubule structure of the mammalian skeletal muscle. PMID:24921337

Local strain heterogeneity and elastic relaxation dynamics associated with relaxor behavior in the single-crystal perovskite Pb (I n1 /2N b1 /2 ) O3-PbZr O3-Pb (M g1 /3N b2 /3 ) O3-PbTi O3

NASA Astrophysics Data System (ADS)

He, Wenhui; Carpenter, Michael A.; Lampronti, Giulio I.; Li, Qiang; Yan, Qingfeng

2017-10-01

Recently, Pb (In1/2Nb1/2 ) O3-PbZr O3-Pb (Mg1/3Nb2/3 ) O3-PbTiO3 (PIN-PZ-PMN-PT) relaxor single crystals were demonstrated to possess improved temperature-insensitive properties, which would be desirable for high-power device applications. The relaxor character associated with the development of local random fields (RFs) and a high rhombohedral-tetragonal (R-T) ferroelectric transition temperature (TR-T>120°C) would be critical for the excellent properties. A significant effect of the chemical substitution of In3+ and Zr4+ in PMN-PT to give PIN-PZ-PMN-PT is the development of local strain heterogeneity, which acts to suppress the development of macroscopic shear strains without suppressing the development of local ferroelectric moments and contribute substantially to the RFs in PIN-PZ-PMN-PT. Measurements of elastic and anelastic properties by resonant ultrasound spectroscopy show that PIN-PZ-PMN-PT crystal has a quite different form of elastic anomaly due to Vogel-Fulcher freezing, rather than the a discrete cubic-T transition seen in a single crystal of PMN-28PT. It also has high acoustic loss of the relaxor phase down to TR-T. Analysis of piezoresponse force microscopy phase images at different temperatures provides a quantitative insight into the extent to which the RFs influence the microdomain structure and the short-range order correlation length 〈ξ 〉 .

Islet Transplantation in Type 1 Diabetes: Ongoing Challenges, Refined Procedures, and Long-Term Outcome

PubMed Central

Shapiro, A.M. James

2012-01-01

Remarkable progress has been made in islet transplantation over a span of 40 years. Once just an experimental curiosity in mice, this therapy has moved forward, and can now provide robust therapy for highly selected patients with type 1 diabetes (T1D), refractory to stabilization by other means. This progress could not have occurred without extensive dynamic international collaboration. Currently, 1,085 patients have undergone islet transplantation at 40 international sites since the Edmonton Protocol was reported in 2000 (752 allografts, 333 autografts), according to the Collaborative Islet Transplant Registry. The long-term results of islet transplantation in selected centers now match registry data of pancreas-alone transplantation, with 6 sites reporting five-year insulin independence rates ≥50%. Islet transplantation has been criticized for the use of multiple donor pancreas organs, but progress has also occurred in single-donor success, with 10 sites reporting increased single-donor engraftment. The next wave of innovative clinical trial interventions will address instant blood-mediated inflammatory reaction (IBMIR), apoptosis, and inflammation, and will translate into further marked improvements in single-donor success. Effective control of auto- and alloimmunity is the key to long-term islet function, and high-resolution cellular and antibody-based assays will add considerable precision to this process. Advances in immunosuppression, with new antibody-based targeting of costimulatory blockade and other T-B cellular signaling, will have further profound impact on the safety record of immunotherapy. Clinical trials will move forward shortly to test out new human stem cell derived islets, and in parallel trials will move forward, testing pig islets for compatibility in patients. Induction of immunological tolerance to self-islet antigens and to allografts is a difficult challenge, but potentially within our grasp. PMID:23804275

Superresolution microscope image reconstruction by spatiotemporal object decomposition and association: application in resolving t-tubule structure in skeletal muscle.

PubMed

Sun, Mingzhai; Huang, Jiaqing; Bunyak, Filiz; Gumpper, Kristyn; De, Gejing; Sermersheim, Matthew; Liu, George; Lin, Pei-Hui; Palaniappan, Kannappan; Ma, Jianjie

2014-05-19

One key factor that limits resolution of single-molecule superresolution microscopy relates to the localization accuracy of the activated emitters, which is usually deteriorated by two factors. One originates from the background noise due to out-of-focus signals, sample auto-fluorescence, and camera acquisition noise; and the other is due to the low photon count of emitters at a single frame. With fast acquisition rate, the activated emitters can last multiple frames before they transiently switch off or permanently bleach. Effectively incorporating the temporal information of these emitters is critical to improve the spatial resolution. However, majority of the existing reconstruction algorithms locate the emitters frame by frame, discarding or underusing the temporal information. Here we present a new image reconstruction algorithm based on tracklets, short trajectories of the same objects. We improve the localization accuracy by associating the same emitters from multiple frames to form tracklets and by aggregating signals to enhance the signal to noise ratio. We also introduce a weighted mean-shift algorithm (WMS) to automatically detect the number of modes (emitters) in overlapping regions of tracklets so that not only well-separated single emitters but also individual emitters within multi-emitter groups can be identified and tracked. In combination with a maximum likelihood estimator method (MLE), we are able to resolve low to medium density of overlapping emitters with improved localization accuracy. We evaluate the performance of our method with both synthetic and experimental data, and show that the tracklet-based reconstruction is superior in localization accuracy, particularly for weak signals embedded in a strong background. Using this method, for the first time, we resolve the transverse tubule structure of the mammalian skeletal muscle.