High-power flexible AlGaN/GaN heterostructure field-effect transistors with suppression of negative differential conductance

NASA Astrophysics Data System (ADS)

Oh, Seung Kyu; Cho, Moon Uk; Dallas, James; Jang, Taehoon; Lee, Dong Gyu; Pouladi, Sara; Chen, Jie; Wang, Weijie; Shervin, Shahab; Kim, Hyunsoo; Shin, Seungha; Choi, Sukwon; Kwak, Joon Seop; Ryou, Jae-Hyun

2017-09-01

We investigate thermo-electronic behaviors of flexible AlGaN/GaN heterostructure field-effect transistors (HFETs) for high-power operation of the devices using Raman thermometry, infrared imaging, and current-voltage characteristics. A large negative differential conductance observed in HFETs on polymeric flexible substrates is confirmed to originate from the decreasing mobility of the two-dimensional electron gas channel caused by the self-heating effect. We develop high-power transistors by suppressing the negative differential conductance in the flexible HFETs using chemical lift-off and modified Ti/Au/In metal bonding processes with copper (Cu) tapes for high thermal conductivity and low thermal interfacial resistance in the flexible hybrid structures. Among different flexible HFETs, the ID of the HFETs on Cu with Ni/Au/In structures decreases only by 11.3% with increasing drain bias from the peak current to the current at VDS = 20 V, which is close to that of the HFETs on Si (9.6%), solving the problem of previous flexible AlGaN/GaN transistors.

Challenges/issues of NIS used in particle accelerator facilities

NASA Astrophysics Data System (ADS)

Faircloth, Dan

2013-09-01

High current, high duty cycle negative ion sources are an essential component of many high power particle accelerators. This talk gives an overview of the state-of-the-art sources used around the world. Volume, surface and charge exchange negative ion production processes are detailed. Cesiated magnetron and Penning surface plasma sources are discussed along with surface converter sources. Multicusp volume sources with filament and LaB6 cathodes are described before moving onto RF inductively coupled volume sources with internal and external antennas. The major challenges facing accelerator facilities are detailed. Beam current, source lifetime and reliability are the most pressing. The pros and cons of each source technology is discussed along with their development programs. The uncertainties and unknowns common to these sources are discussed. The dynamics of cesium surface coverage and the causes of source variability are still unknown. Minimizing beam emittance is essential to maximizing the transport of high current beams; space charge effects are very important. The basic physics of negative ion production is still not well understood, theoretical and experimental programs continue to improve this, but there are still many mysteries to be solved.

Daily stress and the trajectory of mood: spillover, response assimilation, contrast, and chronic negative affectivity.

PubMed

Marco, C A; Suls, J

1993-06-01

Experience sampling methodology was used to examine the effects of current and prior problems on negative mood within and across days. Forty male community residents wore signal watches and kept dairy records of problem occurrence and mood 8 times a day for 8 consecutive days. Trait negative affectivity (NA), prior mood, and concurrent stress were related to mood during the day. Mood in response to a current problem was worse if the prior time had been problem free than if the prior time had been stressful. High NA Ss were more reactive to concurrent stressors than were low NAs, but the effect was small. NA and current-day stress were the major influences of mood across days. High NAs were more distressed by current-day problems and recovered more slowly from problems of the preceding day. The benefits of conceptualizing the effects of daily stressors on mood in terms of spillover, response assimilation, habituation, and contrast are discussed.

Multiple negative differential resistance devices with ultra-high peak-to-valley current ratio for practical multi-valued logic and memory applications

NASA Astrophysics Data System (ADS)

Shin, Sunhae; Rok Kim, Kyung

2015-06-01

In this paper, we propose a novel multiple negative differential resistance (NDR) device with ultra-high peak-to-valley current ratio (PVCR) over 106 by combining tunnel diode with a conventional MOSFET, which suppresses the valley current with transistor off-leakage level. Band-to-band tunneling (BTBT) in tunnel junction provides the first peak, and the second peak and valley are generated from the suppression of diffusion current in tunnel diode by the off-state MOSFET. The multiple NDR curves can be controlled by doping concentration of tunnel junction and the threshold voltage of MOSFET. By using complementary multiple NDR devices, five-state memory is demonstrated only with six transistors.

Negative affect as a moderator of the relationship between hookup motives and hookup consequences.

PubMed

Montes, Kevin S; Napper, Lucy E; Froidevaux, Nicole M; Kenney, Shannon; LaBrie, Joseph W

2016-01-01

The current study examined the extent to which negative affect moderates the relationships between distinct hookup motives and hookup consequences. Data were collected from 271 heavy-drinking undergraduate college students. Students from 3 US universities completed online surveys assessing hooking up-related motives, behaviors, and consequences. The results showed that conformity motives to hookup and negative affect predicted hookup consequences. Furthermore, negative affect moderated the relationship between hooking up for relationship reasons and hookup consequences. Specifically, among students with high negative affect, hooking up to secure a long-term relationship was positively associated with hookup consequences whereas among students with low negative affect, securing a long-term relationship was negatively associated with hookup consequences. These findings highlight the role that motives and negative affect play in the prediction of negative hookup consequences. Moreover, the findings from the current study have the potential to inform prevention efforts designed to reduce hookup consequences.

Single element of the matrix source of negative hydrogen ions: Measurements of the extracted currents combined with diagnostics

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

Yordanov, D., E-mail: yordanov@phys.uni-sofia.bg; Lishev, St.; Shivarova, A.

2016-02-15

Combining measurements of the extracted currents with probe and laser-photodetachment diagnostics, the study is an extension of recent tests of factors and gas-discharge conditions stimulating the extraction of volume produced negative ions. The experiment is in a single element of a rf source with the design of a matrix of small-radius inductively driven discharges. The results are for the electron and negative-ion densities, for the plasma potential and for the electronegativity in the vicinity of the plasma electrode as well as for the currents of the extracted negative ions and electrons. The plasma-electrode bias and the rf power have beenmore » varied. Necessity of a high bias to the plasma electrode and stable linear increase of the extracted currents with the rf power are the main conclusions.« less

High energy density redox flow device

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

Carter, W. Craig; Chiang, Yet-Ming; Duduta, Mihai

2017-04-04

Redox flow devices are described including a positive electrode current collector, a negative electrode current collector, and an ion-permeable membrane separating said positive and negative current collectors, positioned and arranged to define a positive electroactive zone and a negative electroactive zone; wherein at least one of said positive and negative electroactive zone comprises a flowable semi-solid composition comprising ion storage compound particles capable of taking up or releasing said ions during operation of the cell, and wherein the ion storage compound particles have a polydisperse size distribution in which the finest particles present in at least 5 vol % ofmore » the total volume, is at least a factor of 5 smaller than the largest particles present in at least 5 vol % of the total volume.« less

Phosphorene/rhenium disulfide heterojunction-based negative differential resistance device for multi-valued logic

NASA Astrophysics Data System (ADS)

Shim, Jaewoo; Oh, Seyong; Kang, Dong-Ho; Jo, Seo-Hyeon; Ali, Muhammad Hasnain; Choi, Woo-Young; Heo, Keun; Jeon, Jaeho; Lee, Sungjoo; Kim, Minwoo; Song, Young Jae; Park, Jin-Hong

2016-11-01

Recently, negative differential resistance devices have attracted considerable attention due to their folded current-voltage characteristic, which presents multiple threshold voltage values. Because of this remarkable property, studies associated with the negative differential resistance devices have been explored for realizing multi-valued logic applications. Here we demonstrate a negative differential resistance device based on a phosphorene/rhenium disulfide (BP/ReS2) heterojunction that is formed by type-III broken-gap band alignment, showing high peak-to-valley current ratio values of 4.2 and 6.9 at room temperature and 180 K, respectively. Also, the carrier transport mechanism of the BP/ReS2 negative differential resistance device is investigated in detail by analysing the tunnelling and diffusion currents at various temperatures with the proposed analytic negative differential resistance device model. Finally, we demonstrate a ternary inverter as a multi-valued logic application. This study of a two-dimensional material heterojunction is a step forward toward future multi-valued logic device research.

3D numerical simulations of negative hydrogen ion extraction using realistic plasma parameters, geometry of the extraction aperture and full 3D magnetic field map

NASA Astrophysics Data System (ADS)

Mochalskyy, S.; Wünderlich, D.; Ruf, B.; Franzen, P.; Fantz, U.; Minea, T.

2014-02-01

Decreasing the co-extracted electron current while simultaneously keeping negative ion (NI) current sufficiently high is a crucial issue on the development plasma source system for ITER Neutral Beam Injector. To support finding the best extraction conditions the 3D Particle-in-Cell Monte Carlo Collision electrostatic code ONIX (Orsay Negative Ion eXtraction) has been developed. Close collaboration with experiments and other numerical models allows performing realistic simulations with relevant input parameters: plasma properties, geometry of the extraction aperture, full 3D magnetic field map, etc. For the first time ONIX has been benchmarked with commercial positive ions tracing code KOBRA3D. A very good agreement in terms of the meniscus position and depth has been found. Simulation of NI extraction with different e/NI ratio in bulk plasma shows high relevance of the direct negative ion extraction from the surface produced NI in order to obtain extracted NI current as in the experimental results from BATMAN testbed.

Under threat by popular vote: German-speaking immigrants’ affect and cognitions following the Swiss vote against mass immigration

PubMed Central

Janke, Stefan; Greifeneder, Rainer

2017-01-01

A popular initiative in support of regulating future immigration to Switzerland was accepted by the electorate in 2014. Assuming that the initiative acted as an exclusionary threat for current immigrants of Switzerland, we conducted an online survey among a sample of highly-skilled German-speaking immigrants (“expats”). Participants reported having experienced negative affect following the vote. Moreover, having a more left-wing orientation, living in a political constituency that had voted pro-regulation and having proportionally few Swiss friends positively predicted negative affect following the vote. Negative affect was associated with a reported negative change in one’s attitudes towards Switzerland, increased considerations to leave the country, and impaired satisfaction with life. In sum, the results suggest that a powerful exclusionary threat such as a national vote may be experienced as distressful by highly-skilled immigrants currently living in the country. PMID:28406990

Under threat by popular vote: German-speaking immigrants' affect and cognitions following the Swiss vote against mass immigration.

PubMed

Rudert, Selma Carolin; Janke, Stefan; Greifeneder, Rainer

2017-01-01

A popular initiative in support of regulating future immigration to Switzerland was accepted by the electorate in 2014. Assuming that the initiative acted as an exclusionary threat for current immigrants of Switzerland, we conducted an online survey among a sample of highly-skilled German-speaking immigrants ("expats"). Participants reported having experienced negative affect following the vote. Moreover, having a more left-wing orientation, living in a political constituency that had voted pro-regulation and having proportionally few Swiss friends positively predicted negative affect following the vote. Negative affect was associated with a reported negative change in one's attitudes towards Switzerland, increased considerations to leave the country, and impaired satisfaction with life. In sum, the results suggest that a powerful exclusionary threat such as a national vote may be experienced as distressful by highly-skilled immigrants currently living in the country.

High-voltage plasma interactions calculations using NASCAP/LEO

NASA Technical Reports Server (NTRS)

Mandell, M. J.; Katz, I.

1990-01-01

This paper reviews four previous simulations (two laboratory and two space-flight) of interactions of a high-voltage spacecraft with a plasma under low-earth orbit conditions, performed using a three-dimensional computer code NASCAP/LEO. Results show that NASCAP/LEO can perform meaningful simulations of high-voltage plasma interactions taking into account three-dimensional effects of geometry, spacecraft motion, and magnetic field. Two new calculations are presented: (1) for current collection by 1-mm pinholes in wires (showing that a pinhole in a wire can collect far more current than a similar pinhole in a flat plate); and (2) current collection by Charge-2 mother vehicle launched in December 1985. It is shown that the Charge-2 calculations predicted successfully ion collection at negative bias, the floating potential of a probe outside or inside the sheath under negative bias conditions, and magnetically limited electron collection under electron beam operation at high altitude.

Electromagnetic pulse-induced current measurement device

NASA Astrophysics Data System (ADS)

Gandhi, Om P.; Chen, Jin Y.

1991-08-01

To develop safety guidelines for exposure to high fields associated with an electromagnetic pulse (EMP), it is necessary to devise techniques that would measure the peak current induced in the human body. The main focus of this project was to design, fabricate, and test a portable, self-contained stand-on device that would measure and hold the peak current and the integrated change Q. The design specifications of the EMP-Induced Current Measurement Device are as follows: rise time of the current pulse, 5 ns; peak current, 20-600 A; charge Q, 0-20 microcoulombs. The device uses a stand-on parallel-plate bilayer sensor and fast high-frequency circuit that are well-shielded against spurious responses to high incident fields. Since the polarity of the incident peak electric field of the EMP may be either positive or negative, the induced peak current can also be positive or negative. Therefore, the device is designed to respond to either of these polarities and measure and hold both the peak current and the integrated charge which are simultaneously displayed on two separate 3-1/2 digit displays. The prototype device has been preliminarily tested with the EMP's generated at the Air Force Weapons Laboratory (ALECS facility) at Kirtland AFB, New Mexico.

Optimization of microelectrophoresis to select highly negatively charged sperm.

PubMed

Simon, Luke; Murphy, Kristin; Aston, Kenneth I; Emery, Benjamin R; Hotaling, James M; Carrell, Douglas T

2016-06-01

The sperm membrane undergoes extensive surface remodeling as it matures in the epididymis. During this process, the sperm is encapsulated in an extensive glycocalyx layer, which provides the membrane with its characteristic negative electrostatic charge. In this study, we develop a method of microelectrophoresis and standardize the protocol to isolate sperm with high negative membrane charge. Under an electric field, the percentage of positively charged sperm (PCS), negatively charged sperm (NCS), and neutrally charged sperm was determined for each ejaculate prior to and following density gradient centrifugation (DGC), and evaluated for sperm DNA damage, and histone retention. Subsequently, PCS, NCS, and neutrally charged sperm were selected using an ICSI needle and directly analyzed for DNA damage. When raw semen was analyzed using microelectrophoresis, 94 % were NCS. In contrast, DGC completely or partially stripped the negative membrane charge from sperm resulting PCS and neutrally charged sperm, while the charged sperm populations are increased with an increase in electrophoretic current. Following DGC, high sperm DNA damage and abnormal histone retention were inversely correlated with percentage NCS and directly correlated with percentage PCS. NCS exhibited significantly lower DNA damage when compared with control (P < 0.05) and PCS (P < 0.05). When the charged sperm population was corrected for neutrally charged sperm, sperm DNA damage was strongly associated with NCS at a lower electrophoretic current. The results suggest that selection of NCS at lower current may be an important biomarker to select healthy sperm for assisted reproductive treatment.

Effect of high energy electrons on H{sup −} production and destruction in a high current DC negative ion source for cyclotron

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

Onai, M., E-mail: onai@ppl.appi.keio.ac.jp; Fujita, S.; Hatayama, A.

2016-02-15

Recently, a filament driven multi-cusp negative ion source has been developed for proton cyclotrons in medical applications. In this study, numerical modeling of the filament arc-discharge source plasma has been done with kinetic modeling of electrons in the ion source plasmas by the multi-cusp arc-discharge code and zero dimensional rate equations for hydrogen molecules and negative ions. In this paper, main focus is placed on the effects of the arc-discharge power on the electron energy distribution function and the resultant H{sup −} production. The modelling results reasonably explains the dependence of the H{sup −} extraction current on the arc-discharge powermore » in the experiments.« less

An advanced negative hydrogen ion source

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

Goncharov, Alexey A., E-mail: gonchar@iop.kiev.ua; Dobrovolsky, Andrey N.; Goretskii, Victor P.

2016-02-15

The results of investigation of emission productivity of negative particles source with cesiated combined discharge are presented. A cylindrical beam of negative hydrogen ions with density about 2 A/cm{sup 2} in low noise mode on source emission aperture is obtained. The total beam current values are up to 200 mA for negative hydrogen ions and up to 1.5 A for all negative particles with high divergence after source. The source has simple design and can produce stable discharge with low level of oscillation.

On the Maximum and Characteristic Curvature of Current Density of High tc Superconductor Ybco in Flux Relaxation

NASA Astrophysics Data System (ADS)

Ye, Jiping; Sun, Lei; Dai, Xianxi; Dai, Jixin

The flux relaxation is one of important topics in the studies of high Tc superconductivity, because it is related to the energy loss in practical applications. There are many mechanisms, theories and relaxation laws suggested in the literatures. It is very interesting to test them according to the characters and compare them with the experiments. Some people think that the characters of the famous theories are their negative curvature. According our inversion solution, the relaxation ArcG law and experimental data analysis, the relaxation law has both positive and negative signs. This prediction is hopeful to be checked by experiments in future. The current densities of many high Tc superconductors decrease very rapidly in the early time in the relaxation. People do not know what their maximums are. In this work, a theory to determine these maximums of the current densities is presented. The theory is concretely realized by inversion for some real data of the YBCO and their maximum current densities are obtained.

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

Hanada, M., E-mail: hanada.masaya@jaea.go.jp; Kojima, A.; Tobari, H.

In order to realize negative ion sources and accelerators to be applicable to International Thermonuclear Experimental Reactor and JT-60 Super Advanced, a large cesium (Cs)-seeded negative ion source and a multi-aperture and multi-stage electric acceleration have been developed at Japan Atomic Energy Agency (JAEA). Long pulse production and acceleration of the negative ion beams have been independently carried out. The long pulse production of the high current beams has achieved 100 s at the beam current of 15 A by modifying the JT-60 negative ion source. The pulse duration time is increased three times longer than that before the modification.more » As for the acceleration, a pulse duration time has been also extended two orders of magnitudes from 0.4 s to 60 s. The developments of the negative ion source and acceleration at JAEA are well in progress towards the realization of the negative ion sources and accelerators for fusion applications.« less

The transport systems of Ventricaria ventricosa: hypotonic and hypertonic turgor regulation.

PubMed

Bisson, M A; Beilby, M J

2002-11-01

The time course of hypertonic and hypotonic turgor regulation was studied in Ventricaria (Valonia) using pressure probe and I/V(current-voltage) analysis. Of 11 cells, 9 exhibited hypertonic turgor regulation, ranging from 100% regulation in 150 min to 14% regulation (14% recovery of the decrease in turgor) in 314 min. Some cells began regulating immediately, others took up to 90 min to begin. The resting PD (potential difference) became more positive in most cells. The I/V characteristics became more nonlinear with high resistance between -150 and -20 mV and negative conductance region near -70 mV. Prolonged (16 sec) voltage clamps to negative levels (-100 to -150 mV) showed progressively more rapid current turn-off, but subsequent I/V characteristics were not affected. Clamping to +150 mV, however, abolished the high conductance between -50 and +100 mV to yield a uniform high resistance I/V characteristic, similar to that in high [K+]o. Decreasing illumination from 2.02 micromol sec(-1) m(-2) to 0.5 micromol sec(-1)1 m(-2) had a similar effect. Two out of a total of three cells exhibited hypotonic turgor regulation. Both cells started regulating within minutes and achieved near 50% regulation within 50 min. The PD became more negative. The I/V curves exhibited high resistance between +50 and +150 mV. The characteristics were similar to those in cells exposed to low [K+]o. Prolonged voltage clamps to both negative and positive levels showed slow current increase. Decreased illumination increased the membrane resistance.

Note: Expanding the bandwidth of the ultra-low current amplifier using an artificial negative capacitor.

PubMed

Xie, Kai; Liu, Yan; Li, XiaoPing; Guo, Lixin; Zhang, Hanlu

2016-04-01

The bandwidth and low noise characteristics are often contradictory in ultra-low current amplifier, because an inevitable parasitic capacitance is paralleled with the high value feedback resistor. In order to expand the amplifier's bandwidth, a novel approach was proposed by introducing an artificial negative capacitor to cancel the parasitic capacitance. The theory of the negative capacitance and the performance of the improved amplifier circuit with the negative capacitor are presented in this manuscript. The test was conducted by modifying an ultra-low current amplifier with a trans-impedance gain of 50 GΩ. The results show that the maximum bandwidth was expanded from 18.7 Hz to 3.3 kHz with more than 150 times of increase when the parasitic capacitance (∼0.17 pF) was cancelled. Meanwhile, the rise time decreased from 18.7 ms to 0.26 ms with no overshot. Any desired bandwidth or rise time within these ranges can be obtained by adjusting the ratio of cancellation of the parasitic and negative capacitance. This approach is especially suitable for the demand of rapid response to weak current, such as transient ion-beam detector, mass spectrometry analysis, and fast scanning microscope.

Investigation of high duty factor ISR RFQ-1000

NASA Astrophysics Data System (ADS)

Lu, Y. R.; Chen, C. E.; Fang, J. X.; Gao, S. L.; Guo, J. F.; Guo, Z. Y.; Li, D. S.; Li, W. G.; Pan, O. J.; Ren, X. T.; Wu, Y.; Yan, X. Q.; Yu, J. X.; Yu, M. L.; Ratzinger, U.; Deitinghoff, H.; Klein, H.; Schempp, A.

2003-12-01

Two Integral Split Ring (ISR) RFQs with high duty factor of 16.7% have been designed for the application of heavy ion implantation and built in the past several years at Institute of Heavy Ion Physics (IHIP) in Peking University. Two kinds of PIG ion sources with permanent magnets and LEBT were installed and optimized for the injection into these two RFQs. The positive O+ and negative O- ions were extracted and accelerated separately as well as simultaneously. The output macro pulse O- beam current reached 660 μA at a transmission efficiency of more than 82%. The N+ beam was also accelerated with similar transmission efficiency, but the output current intensity for positive ions were lower than the negative ions because of the extracted current limitation of ion sources. The improvements, especially for high duty factor and experimental results with the 1 MeV ISR RFQ will be presented in this paper.

They all do it, will you? Event-related potential evidence of herding behavior in online peer-to-peer lending.

PubMed

Yu, Haihong; Dan, MengHan; Ma, Qingguo; Jin, Jia

2018-05-14

As herding is a typical characteristic of human behavior, many researchers have found the existence of herding behavior in online peer-to-peer lending through empirical surveys. However, the underlying neural basis of this phenomenon is still unclear. In the current study, we studied the neural activities of herding at decision-making stage and feedback stage using event-related potentials (ERPs). Our results showed that at decision-making stage, larger error related negativity (ERN) amplitude was induced under low-proportion conditions than that of high-proportion conditions. Meanwhile, during feedback stage, negative feedback elicited larger feedback related negativity (FRN) amplitude than that of positive feedback under low-proportion conditions, however, there was no significant FRN difference under high-proportion conditions. The current study suggests that herding behavior in online peer-to-peer lending is related to individual's risk perception and is possible to avoid negative emotions brought by failed investments. Copyright © 2018 Elsevier B.V. All rights reserved.

Development of the negative ion beams relevant to ITER and JT-60SA at Japan Atomic Energy Agency.

PubMed

Hanada, M; Kojima, A; Tobari, H; Nishikiori, R; Hiratsuka, J; Kashiwagi, M; Umeda, N; Yoshida, M; Ichikawa, M; Watanabe, K; Yamano, Y; Grisham, L R

2016-02-01

In order to realize negative ion sources and accelerators to be applicable to International Thermonuclear Experimental Reactor and JT-60 Super Advanced, a large cesium (Cs)-seeded negative ion source and a multi-aperture and multi-stage electric acceleration have been developed at Japan Atomic Energy Agency (JAEA). Long pulse production and acceleration of the negative ion beams have been independently carried out. The long pulse production of the high current beams has achieved 100 s at the beam current of 15 A by modifying the JT-60 negative ion source. The pulse duration time is increased three times longer than that before the modification. As for the acceleration, a pulse duration time has been also extended two orders of magnitudes from 0.4 s to 60 s. The developments of the negative ion source and acceleration at JAEA are well in progress towards the realization of the negative ion sources and accelerators for fusion applications.

Current leakage for low altitude satellites - Modeling applications. [simulation of high voltage solar cell array in ionospheric plasma environment

NASA Technical Reports Server (NTRS)

Konradi, A.; Mccoy, J. E.; Garriott, O. K.

1979-01-01

To simulate the behavior of a high voltage solar cell array in the ionospheric plasma environment, the large (90 ft x 55 ft diameter) vacuum chamber was used to measure the high-voltage plasma interactions of a 3 ft x 30 ft conductive panel. The chamber was filled with Nitrogen and Argon plasma at electron densities of up to 1,000,000 per cu cm. Measurements of current flow to the plasma were made in three configurations: (a) with one end of the panel grounded, (b) with the whole panel floating while a high bias was applied between the ends of the panel, and (c) with the whole panel at high negative voltage with respect to the chamber walls. The results indicate that a simple model with a constant panel conductivity and plasma resistance can adequately describe the voltage distribution along the panel and the plasma current flow. As expected, when a high potential difference is applied to the panel ends more than 95% of the panel floats negative with respect to the plasma.

The relation between schizotypy and early attention to rejecting interactions: The influence of neuroticism

PubMed Central

Premkumar, Preethi; Onwumere, Juliana; Albert, Jacobo; Kessel, Dominique; Kumari, Veena; Kuipers, Elizabeth; Carretié, Luis

2015-01-01

Abstract Objectives: Schizotypy relates to rejection sensitivity (anxiety reflecting an expectancy of social exclusion) and neuroticism (excessive evaluation of negative emotions). Positive schizotypy (e.g., perceptual aberrations and odd beliefs) and negative schizotypy (e.g., social and physical anhedonia) could relate to altered attention to rejection because of neuroticism. Methods: Forty-one healthy individuals were assessed on positive and negative schizotypy and neuroticism, and event-related potentials during rejecting, accepting and neutral scenes. Participants were categorised into high, moderate and low neuroticism groups. Using temporo-spatial principal components analyses, P200 (peak latency =290 ms) and P300 amplitudes (peak latency = 390 ms) were measured, reflecting mobilisation of attention and early attention, respectively. Results: Scalp-level and cortical source analysis revealed elevated fronto-parietal N300/P300 amplitude and P200-related dorsal anterior cingulate current density during rejection than acceptance/neutral scenes. Positive schizotypy related inversely to parietal P200 amplitude during rejection. Negative schizotypy related positively to P200 middle occipital current density. Negative schizotypy related positively to parietal P300, where the association was stronger in high and moderate, than low, neuroticism groups. Conclusions: Positive and negative schizotypy relate divergently to attention to rejection. Positive schizotypy attenuates, but negative schizotypy increases rejection-related mobilisation of attention. Negative schizotypy increases early attention to rejection partly due to elevated neuroticism. PMID:26452584

Elevated Appraisals of the Negative Impact of Naturally Occurring Life Events: A Risk Factor for Depressive and Anxiety Disorders

ERIC Educational Resources Information Center

Espejo, Emmanuel Peter; Hammen, Constance; Brennan, Patricia A.

2012-01-01

The tendency to appraise naturally occurring life events (LEs) as having high negative impact may be a predisposing factor for the development of depression and anxiety disorders. In the current study, appraisals of the negative impact of recent LEs were examined in relationship to depressive and anxiety disorders in a sample of 653 adolescents…

Origin of negative resistance in anion migration controlled resistive memory

NASA Astrophysics Data System (ADS)

Banerjee, Writam; Wu, Facai; Hu, Yuan; Wu, Quantan; Wu, Zuheng; Liu, Qi; Liu, Ming

2018-03-01

Resistive random access memory (RRAM) is one of the most promising emerging nonvolatile technologies for the futuristic memory devices. Resistive switching behavior often shows negative resistance (NR), either voltage controlled or current controlled. In this work, the origin of a current compliance dependent voltage controlled NR effect during the resetting of anion migration based RRAM devices is discussed. The N-type voltage controlled NR is a high field driven phenomena. The current conduction within the range of a certain negative voltage is mostly dominated by space charge limited current. But with the higher negative voltage, a field induced tunneling effect is generated in the NR region. The voltage controlled NR is strongly dependent on the compliance current. The area independent behavior indicates the filamentary switching. The peak to valley ratio (PVR) is > 5. The variation of PVR as a function of the conduction band offset is achieved. Compared to other reported works, based on the PVR, it is possible to distinguish the RRAM types. Generally, due to the higher electric field effect on the metallic bridge during RESET, the electrochemical metallization type RRAM shows much higher PVR than the valance change type RRAM.

Positive and negative affect and arousal: cross-sectional and longitudinal associations with adolescent cortisol diurnal rhythms.

PubMed

Hoyt, Lindsay T; Craske, Michelle G; Mineka, Susan; Adam, Emma K

2015-05-01

Psychobiological research with adolescent populations tends to focus on negative mood, stress, and psychopathology, but the role of positive emotions is insufficiently understood. The current study examines the relative contributions of both negative and positive affective experiences to the basal activity of the hypothalamic-pituitary-adrenal axis, measured by levels of cortisol across the waking day. A sample of 315 ethnically and racially diverse high school students (mean age = 17.1 years, 73% female) completed a multiple-day naturalistic salivary cortisol protocol twice over a 5-year period. Along with each saliva sample, youth provided diary reports of their current mood states. Principal components analysis revealed four factors: high arousal positive affect (PA), low arousal PA, high arousal negative affect (NA), and low arousal NA. Multilevel growth curve models suggested that greater high arousal PA was associated with adaptive patterns of hypothalamic-pituitary-adrenal activity: steeper cortisol slope from waking to bedtime and lower evening cortisol, independent of NA. In addition, increases in high arousal PA over the 5-year follow-up period were associated with a steepening of the diurnal cortisol slope (β = -0.038, p = .009; negative values indicate the decrease of cortisol throughout the day) and lower evening cortisol levels (β = -0.661, p = .027) based on within-person fixed-effect regression analysis. This study shows that high arousal PA, such as feeling alert and active, is associated with a steeper decline in cortisol throughout the day. Low arousal positive emotions did not display this relationship.

On the search for the chiral anomaly in Weyl semimetals: the negative longitudinal magnetoresistance

NASA Astrophysics Data System (ADS)

dos Reis, R. D.; Ajeesh, M. O.; Kumar, N.; Arnold, F.; Shekhar, C.; Naumann, M.; Schmidt, M.; Nicklas, M.; Hassinger, E.

2016-08-01

Recently, the existence of massless chiral (Weyl) fermions has been postulated in a class of semi-metals with a non-trivial energy dispersion. These materials are now commonly dubbed Weyl semi-metals (WSM). One predicted property of Weyl fermions is the chiral or Adler-Bell-Jackiw anomaly, a chirality imbalance in the presence of parallel magnetic and electric fields. In WSM, it is expected to induce a negative longitudinal magnetoresistance (MR). Here, we present experimental evidence that the observation of the chiral anomaly can be hindered by an effect called ‘current jetting’. This effect also leads to a strong apparent negative longitudinal MR, but it is characterized by a highly non-uniform current distribution inside the sample. It appears in materials possessing a large field-induced anisotropy of the resistivity tensor, such as almost compensated high-mobility semimetals due to the orbital effect. In case of a non-homogeneous current injection, the potential distribution is strongly distorted in the sample. As a consequence, an experimentally measured potential difference is not proportional to the intrinsic resistance. Our results on the MR of the Weyl semimetal candidate materials NbP, NbAs, TaAs, and TaP exhibit distinct signatures of an inhomogeneous current distribution, such as a field-induced ‘zero resistance’ and a strong dependence of the ‘measured resistance’ on the position, shape, and type of the voltage and current contacts on the sample. A misalignment between the current and the magnetic-field directions can even induce a ‘negative resistance’. Finite-element simulations of the potential distribution inside the sample, using typical resistance anisotropies, are in good agreement with the experimental findings. Our study demonstrates that great care must be taken before interpreting measurements of a negative longitudinal MR as evidence for the chiral anomaly in putative Weyl semimetals.

Relationships between Employment Quality and Intention to Quit: Focus on PhD Candidates as Traditional Workers

ERIC Educational Resources Information Center

Travaglianti, F.; Babic, A.; Hansez, I.

2018-01-01

Current statistics show that the attrition rate among PhD candidates is high (i.e. from 30% to 40% depending on the discipline and the country). This high-attrition rate has an impact on both economic (e.g. negative impact on the return-on investment in doctoral education) and human levels (e.g. negative consequences on candidates' self-esteem and…

Self-focused attention affects subsequent processing of positive (but not negative) performance appraisals.

PubMed

Holzman, Jacob B; Valentiner, David P

2016-03-01

Cognitive-behavioral models highlight the conjoint roles of self-focused attention (SFA), post-event processing (PEP), and performance appraisals in the maintenance of social anxiety. SFA, PEP, and biased performance appraisals are related to social anxiety; however, limited research has examined how SFA affects information-processing following social events. The current study examined whether SFA affects the relationships between performance appraisals and PEP following a social event.. 137 participants with high (n = 72) or low (n = 65) social anxiety were randomly assigned to conditions of high SFA or low SFA while engaging in a standardized social performance. Subsequent performance appraisals and PEP were measured. Immediate performance appraisals were not affected by SFA. High levels of SFA led to a stronger, inverse relationship between immediate positive performance appraisals and subsequent negative PEP. High levels of SFA also led to a stronger, inverse relationship between negative PEP and changes in positive performance appraisals.. Future research should examine whether the current findings, which involved a standardized social performance event, extend to interaction events as well as in a clinical sample. These findings suggest that SFA affects the processing of positive information following a social performance event. SFA is particularly important for understanding how negative PEP undermines positive performance appraisals.. Published by Elsevier Ltd.

The effect of positive symptoms on social cognition in first-episode schizophrenia is modified by the presence of negative symptoms.

PubMed

Bliksted, Vibeke; Videbech, Poul; Fagerlund, Birgitte; Frith, Chris

2017-02-01

There is considerable evidence that patients with schizophrenia have neurocognitive and social-cognitive deficits. It is unclear how such deficits in first-episode schizophrenia relate to current clinical symptoms. Fifty-nine patients with first-episode schizophrenia (FES) were tested using the Danish version of NART (premorbid IQ), subtests from WAIS-III (current IQ), and global cognition using Brief Assessment of Cognition in Schizophrena (BACS), a neurocognitive test battery. Social perception was tested using film clips of everyday interactions (TASIT). Theory of mind (ToM) was tested using silent animations (Animated Triangles Task). The FES subjects had been experiencing psychotic symptoms for several years (mean duration 9.5 years 95% confidence interval (CI [7.6;11.3]). The FES patients were divided into clinical subgroups based on their level of positive and negative symptoms (using SANS and SAPS). Healthy controls were matched to the patients. High levels of negative symptoms were associated with low estimated functional IQ and poor neurocognition and social cognition. All SANS subscales, but Avolition-Apathy, had significant negative impact on social cognition. The effects of positive symptoms were complex. High levels of delusions were associated with higher premorbid IQ. In the presence of high levels of negative symptoms, high levels of positive symptoms were associated with the most comprehensive deficits in social perception, while, in the absence of negative symptoms, high levels of positive symptoms were not associated with such deficits. The results suggest that social-cognitive training will need to take account of the above mentioned effects of symptoms. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

High-capacity FeTiO3/C negative electrode for sodium-ion batteries with ultralong cycle life

NASA Astrophysics Data System (ADS)

Ding, Changsheng; Nohira, Toshiyuki; Hagiwara, Rika

2018-06-01

The development of electrode materials which improve both the energy density and cycle life is one of the most challenging issues facing the practical application of sodium-ion batteries today. In this work, FeTiO3/C nanoparticles are synthesized as negative electrode materials for sodium-ion batteries. The electrochemical performance and charge-discharge mechanism of the FeTiO3/C negative electrode are investigated in an ionic liquid electrolyte at 90 °C. The FeTiO3/C negative electrode delivers a high reversible capacity of 403 mAh g-1 at a current rate of 10 mA g-1, and exhibits high rate capability and excellent cycling stability for up to 2000 cycles. The results indicate that FeTiO3/C is a promising negative electrode material for sodium-ion batteries.

Four large-scale field-aligned current systmes in the dayside high-latitude region

NASA Technical Reports Server (NTRS)

Ohtani, S.; Potemra, T. A.; Newell, P.T.; Zanetti, L. J.; Iijima, T.; Watanabe, M.; Blomberg, L. G.; Elphinstone, R. D.; Murphree, J. S.; Yamauchi, M.

1995-01-01

A system of four current sheets of large-scale field-aligned currents (FACs) was discovered in the data set of simultaneous Viking and Defense Meteorological Satellire Program-F7 (DMSP-F7) crossing of the dayside high-latitude region. This paper reports four examples of this system that were observed in the prenoon sector. The flow polarities of FACs are upward, downward, upward, and downward, from equatorward to poleward. The lowest-latitude upward current is flowing mostly in the central plasma sheet (CPS) precipitation region, often overlapping with the boundary plasma sheet (BPS) at its poleward edge, andis interpreted as a region 2 current. The pair of downward and upward FACs in the middle of te structure are collocated with structured electron precipitation. The precipitation of high-energy (greater than 1 keV) electrons is more intense in the lower-latitude downward current sheet. The highest-latitude downward flowing current sheet is located in a weak, low-energy particle precipitation region, suggesting that this current is flowing on open field lines. Simulaneous observations in the postnoon local time sector reveal the standard three-sheet structure of FACs, sometimes described as region 2, region 1, and mantle (referred to the midday region O) currents. A high correlation was found between the occurrence of the four FAC sheet structure and negative interplanetary magnetic field (IMF) B(sub Y). We discuss the FAC structurein terms of three types of convection cells: the merging, viscous, andlobe cells. During strongly negative IMF B(sub Y), two convection reversals exist in the prenoon sector; one is inside the viscous cell, and the other is between the viscous cell and the lobe cell. This structure of convection flow is supported by the Viking electric field and auroral UV image data. Based on the convection pattern, the four FAC sheet structure is interpreted as the latitude overlap of midday and morning FAC systems. We suggest that the for-current sheet structure is common in a certain prenoon localtime sector during strongly negative IMF B(sub Y).

Understanding the Association Between Negative Symptoms and Performance on Effort-Based Decision-Making Tasks: The Importance of Defeatist Performance Beliefs.

PubMed

Reddy, L Felice; Horan, William P; Barch, Deanna M; Buchanan, Robert W; Gold, James M; Marder, Stephen R; Wynn, Jonathan K; Young, Jared; Green, Michael F

2017-11-13

Effort-based decision-making paradigms are increasingly utilized to gain insight into the nature of motivation deficits. Research has shown associations between effort-based decision making and experiential negative symptoms; however, the associations are not consistent. The current study had two primary goals. First, we aimed to replicate previous findings of a deficit in effort-based decision making among individuals with schizophrenia on a test of cognitive effort. Second, in a large sample combined from the current and a previous study, we sought to examine the association between negative symptoms and effort by including the related construct of defeatist beliefs. The results replicated previous findings of impaired cognitive effort-based decision making in schizophrenia. Defeatist beliefs significantly moderated the association between negative symptoms and effort-based decision making such that there was a strong association between high negative symptoms and deficits in effort-based decision making, but only among participants with high levels of defeatist beliefs. Thus, our findings suggest the relationship between negative symptoms and effort performance may be understood by taking into account the role of defeatist beliefs, and finding that might explain discrepancies in previous studies. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center 2017.

Effects of false feedback on affect, cognition, behavior, and postevent processing: the mediating role of self-focused attention.

PubMed

Makkar, Steve R; Grisham, Jessica R

2013-03-01

Current social phobia models (e.g., Clark & Wells, 1995; Leary & Kowalski, 1995) postulate that socially anxious individuals negatively appraise their anxiety sensations (e.g., sweating, heart racing, blushing) as evidence of poor social performance, and thus fear these anxiety symptoms will be noticed and judged negatively by others. Consequently, they become self-focused and hypervigilant of these sensations and use them to judge how they appear to others. To test this model, high (N=41) and low (N=38) socially anxious participants were shown false physiological feedback regarding an increase or decrease in heart rate prior to and during an impromptu speech task. Relative to participants who observed a false heart rate decrease, those in the increase condition reported higher levels of negative affect, more negative performance appraisals, and more frequent negative ruminative thoughts, and these effects were mediated by an increase in self-focused attention. The unhelpful effects of the physiological feedback were not specific to high socially anxious participants. The results have implications for current cognitive models as well as the treatment of social phobia. Copyright © 2012. Published by Elsevier Ltd.

Note: Expanding the bandwidth of the ultra-low current amplifier using an artificial negative capacitor

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

Xie, Kai, E-mail: kaixie@mail.xidian.edu.cn; Liu, Yan; Li, XiaoPing

2016-04-15

The bandwidth and low noise characteristics are often contradictory in ultra-low current amplifier, because an inevitable parasitic capacitance is paralleled with the high value feedback resistor. In order to expand the amplifier’s bandwidth, a novel approach was proposed by introducing an artificial negative capacitor to cancel the parasitic capacitance. The theory of the negative capacitance and the performance of the improved amplifier circuit with the negative capacitor are presented in this manuscript. The test was conducted by modifying an ultra-low current amplifier with a trans-impedance gain of 50 GΩ. The results show that the maximum bandwidth was expanded from 18.7more » Hz to 3.3 kHz with more than 150 times of increase when the parasitic capacitance (∼0.17 pF) was cancelled. Meanwhile, the rise time decreased from 18.7 ms to 0.26 ms with no overshot. Any desired bandwidth or rise time within these ranges can be obtained by adjusting the ratio of cancellation of the parasitic and negative capacitance. This approach is especially suitable for the demand of rapid response to weak current, such as transient ion-beam detector, mass spectrometry analysis, and fast scanning microscope.« less

Psychometric schizotypy predicts psychotic-like, paranoid, and negative symptoms in daily life.

PubMed

Barrantes-Vidal, Neus; Chun, Charlotte A; Myin-Germeys, Inez; Kwapil, Thomas R

2013-11-01

Positive and negative schizotypy exhibit differential patterns of impairment in social relations, affect, and functioning in daily life. However, studies have not examined the association of schizotypy with real-world expression of psychotic-like, paranoid, and negative symptoms. The present study employed experience-sampling methodology (ESM) to assess positive and negative schizotypy in daily life in a nonclinical sample of 206 Spanish young adults. Participants were prompted randomly 8 times daily for 1 week to complete assessments of their current symptoms and experiences. Positive schizotypy was associated with psychotic-like and paranoid symptoms in daily life. Negative schizotypy was associated with a subset of these symptoms and with negative symptoms in daily life. Momentary stress was associated with psychotic-like and paranoid symptoms, but only for those high in positive schizotypy. Social stress predicted momentary psychotic-like symptoms in both positive and negative schizotypy. Time-lagged analyses indicated that stress at the preceding signal predicted psychotic-like symptoms at the current assessment, but only for individuals high in positive schizotypy. The results are consistent with models linking stress sensitivity with the experience of psychotic symptoms. The findings provide cross-cultural support for the multidimensional model of schizotypy and schizophrenia. Furthermore, the findings demonstrate that ESM is an effective method for predicting the experience of psychotic-like symptoms, as well as their precursors, in daily life. PsycINFO Database Record (c) 2013 APA, all rights reserved.

Phosphorene/rhenium disulfide heterojunction-based negative differential resistance device for multi-valued logic

PubMed Central

Shim, Jaewoo; Oh, Seyong; Kang, Dong-Ho; Jo, Seo-Hyeon; Ali, Muhammad Hasnain; Choi, Woo-Young; Heo, Keun; Jeon, Jaeho; Lee, Sungjoo; Kim, Minwoo; Song, Young Jae; Park, Jin-Hong

2016-01-01

Recently, negative differential resistance devices have attracted considerable attention due to their folded current–voltage characteristic, which presents multiple threshold voltage values. Because of this remarkable property, studies associated with the negative differential resistance devices have been explored for realizing multi-valued logic applications. Here we demonstrate a negative differential resistance device based on a phosphorene/rhenium disulfide (BP/ReS2) heterojunction that is formed by type-III broken-gap band alignment, showing high peak-to-valley current ratio values of 4.2 and 6.9 at room temperature and 180 K, respectively. Also, the carrier transport mechanism of the BP/ReS2 negative differential resistance device is investigated in detail by analysing the tunnelling and diffusion currents at various temperatures with the proposed analytic negative differential resistance device model. Finally, we demonstrate a ternary inverter as a multi-valued logic application. This study of a two-dimensional material heterojunction is a step forward toward future multi-valued logic device research. PMID:27819264

Low pressure and high power rf sources for negative hydrogen ions for fusion applications (ITER neutral beam injection).

PubMed

Fantz, U; Franzen, P; Kraus, W; Falter, H D; Berger, M; Christ-Koch, S; Fröschle, M; Gutser, R; Heinemann, B; Martens, C; McNeely, P; Riedl, R; Speth, E; Wünderlich, D

2008-02-01

The international fusion experiment ITER requires for the plasma heating and current drive a neutral beam injection system based on negative hydrogen ion sources at 0.3 Pa. The ion source must deliver a current of 40 A D(-) for up to 1 h with an accelerated current density of 200 Am/(2) and a ratio of coextracted electrons to ions below 1. The extraction area is 0.2 m(2) from an aperture array with an envelope of 1.5 x 0.6 m(2). A high power rf-driven negative ion source has been successfully developed at the Max-Planck Institute for Plasma Physics (IPP) at three test facilities in parallel. Current densities of 330 and 230 Am/(2) have been achieved for hydrogen and deuterium, respectively, at a pressure of 0.3 Pa and an electron/ion ratio below 1 for a small extraction area (0.007 m(2)) and short pulses (<4 s). In the long pulse experiment, equipped with an extraction area of 0.02 m(2), the pulse length has been extended to 3600 s. A large rf source, with the width and half the height of the ITER source but without extraction system, is intended to demonstrate the size scaling and plasma homogeneity of rf ion sources. The source operates routinely now. First results on plasma homogeneity obtained from optical emission spectroscopy and Langmuir probes are very promising. Based on the success of the IPP development program, the high power rf-driven negative ion source has been chosen recently for the ITER beam systems in the ITER design review process.

Observation of Dust Stream Formation Produced by Low Current, High Voltage Cathode Spots

NASA Technical Reports Server (NTRS)

Foster, John E.

2004-01-01

Macro-particle acceleration driven by low current, high voltage cathode spots has been investigated. The phenomenon was observed to occur when nanometer and micrometer-sized particles in the presence of a discharge plasma were exposed to a high voltage pulse. The negative voltage pulse initiates the formation of multiple, high voltage, low current cathode spots which provides the mechanism of actual acceleration of the charged dust particles. Dust streams generated by this process were detected using laser scattering techniques. The particle impact craters observed at the surface of downstream witness badges were documented using SEM and light microscopy.

Three years of lightning impulse charge moment change measurements in the United States

NASA Astrophysics Data System (ADS)

Cummer, Steven A.; Lyons, Walter A.; Stanley, Mark A.

2013-06-01

We report and analyze 3 years of lightning impulse charge moment change (iCMC) measurements obtained from an automated, real time lightning charge moment change network (CMCN). The CMCN combines U.S. National Lightning Detection Network (NLDN) lightning event geolocations with extremely low frequency (≲1 kHz) data from two stations to provide iCMC measurements across the entire United States. Almost 14 million lightning events were measured in the 3 year period. We present the statistical distributions of iCMC versus polarity and NLDN-measured peak current, including corrections for the detection efficiency of the CMCN versus peak current. We find a broad distribution of iCMC for a given peak current, implying that these parameters are at best only weakly correlated. Curiously, the mean iCMC does not monotonically increase with peak current, and in fact, drops for positive CG strokes above +150 kA. For all positive strokes, there is a boundary near 20 C km that separates seemingly distinct populations of high and low iCMC strokes. We also explore the geographic distribution of high iCMC lightning strokes. High iCMC positive strokes occur predominantly in the northern midwest portion of the U.S., with a secondary peak over the gulf stream region just off the U.S. east coast. High iCMC negative strokes are also clustered in the midwest, although somewhat south of most of the high iCMC positive strokes. This is a region far from the locations of maximum occurrence of high peak current negative strokes. Based on assumed iCMC thresholds for sprite production, we estimate that approximately 35,000 positive polarity and 350 negative polarity sprites occur per year over the U.S. land and near-coastal areas. Among other applications, this network is useful for the nowcasting of sprite-producing storms and storm regions.

Current-voltage characteristics of dc corona discharges in air between coaxial cylinders

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

Zheng, Yuesheng, E-mail: yueshengzheng@fzu.edu.cn; Zhang, Bo, E-mail: shizbcn@tsinghua.edu.cn; He, Jinliang, E-mail: hejl@tsinghua.edu.cn

This paper presents the experimental measurement and numerical analysis of the current-voltage characteristics of dc corona discharges in air between coaxial cylinders. The current-voltage characteristics for both positive and negative corona discharges were measured within a specially designed corona cage. Then the measured results were fitted by different empirical formulae and analyzed by the fluid model. The current-voltage characteristics between coaxial cylinders can be expressed as I = C(U − U{sub 0}){sup m}, where m is within the range 1.5–2.0, which is similar to the point-plane electrode system. The ionization region has no significant effect on the current-voltage characteristic under a low corona current,more » while it will affect the distribution for the negative corona under a high corona current. The surface onset fields and ion mobilities were emphatically discussed.« less

Negative affect in at-risk youth: Outcome expectancies mediate relations with both regular and electronic cigarette use.

PubMed

Miller, Stephen; Pike, James; Stacy, Alan W; Xie, Bin; Ames, Susan L

2017-06-01

Despite the general trend of declining use of traditional cigarettes among young adults in the United States, alternative high school students continue to smoke cigarettes and electronic cigarettes at rates much higher than do students attending regular high schools. Challenging life circumstances leading to elevated levels of negative affect may account for increased smoking behavior in this population. Further, a belief in the negative affect-reducing qualities of nicotine may mediate this effect. The current study tested the hypothesis that negative reinforcing outcome expectancies mediate the relationship between negative affect on smoking susceptibility in nonusers, smoking frequency in users, and smoking experimentation in the overall sample. Results support the hypothesis that negative affect in alternative high school students is correlated with smoking experimentation, smoking willingness, and smoking frequency and that the relationship between negative affect and smoking behavior outcomes is mediated by negative reinforcing outcome expectancies (i.e., beliefs in the negative affect-reducing effects of smoking). This finding was supported for both cigarettes and electronic cigarettes and coincides with a rapid increase in the number of high school students nationally who have experimented with electronic cigarettes. Future antismoking initiatives directed at at-risk youth should consider integrating healthier negative affect reduction techniques to counter the use of nicotine products. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Effect of CTA Tube Current on Spot Sign Detection and Accuracy for Prediction of Intracerebral Hemorrhage Expansion.

PubMed

Morotti, A; Romero, J M; Jessel, M J; Brouwers, H B; Gupta, R; Schwab, K; Vashkevich, A; Ayres, A; Anderson, C D; Gurol, M E; Viswanathan, A; Greenberg, S M; Rosand, J; Goldstein, J N

2016-05-19

Reduction of CT tube current is an effective strategy to minimize radiation load. However, tube current is also a major determinant of image quality. We investigated the impact of CTA tube current on spot sign detection and diagnostic performance for intracerebral hemorrhage expansion. We retrospectively analyzed a prospectively collected cohort of consecutive patients with primary intracerebral hemorrhage from January 2001 to April 2015 who underwent CTA. The study population was divided into 2 groups according to the median CTA tube current level: low current (<350 mA) and high current (≥350 mA). CTA first-pass readings for spot sign presence were independently analyzed by 2 readers. Baseline and follow-up hematoma volumes were assessed by semiautomated computer-assisted volumetric analysis. Sensitivity, specificity, positive and negative predictive values, and accuracy of spot sign in predicting hematoma expansion were calculated. This study included 709 patients (288 and 421 in the low- and high-current groups, respectively). A higher proportion of low-current scans identified at least 1 spot sign (20.8% versus 14.7%, P = .034), but hematoma expansion frequency was similar in the 2 groups (18.4% versus 16.2%, P = .434). Sensitivity and positive and negative predictive values were not significantly different between the 2 groups. Conversely, high-current scans showed superior specificity (91% versus 84%, P = .015) and overall accuracy (84% versus 77%, P = .038). CTA obtained at high levels of tube current showed better diagnostic accuracy for prediction of hematoma expansion by using spot sign. These findings may have implications for future studies using the CTA spot sign to predict hematoma expansion for clinical trials. © 2016 American Society of Neuroradiology.

Self-evaluative and emotion processes linked with brooding rumination among adolescents

PubMed Central

Burwell, Rebecca A.

2016-01-01

Rumination has been linked with a number of deleterious outcomes, though relatively little is known about self-evaluative and emotion processes by which it develops. The current investigation uses a prospective, longitudinal design and self-report measures to examine the role of contingent self-worth, perfectionism, negative emotion beliefs, and suppression of negative emotion in predicting the development of brooding and reflective forms of rumination among 168 adolescents (98 girls, 79.6% European-American) undergoing the transition to high school (Mage = 13.58). Results of structural equation modeling indicate that self-evaluative vulnerability (i.e., self-worth contingencies, perfectionism) and negative emotion beliefs, but not the suppression of negative emotion, predict brooding (but not reflective) rumination. The current study demonstrates how brooding is intertwined with views of self and core assumptions about emotion. PMID:25900099

The relation of early experienced negative life events and current itch. A longitudinal study among adolescents in Oslo, Norway.

PubMed

Lien, Lars; Halvorsen, Jon Anders; Haavet, Ole Rikard; Dalgard, Florence

2012-03-01

Negative life events have impact on mental health and skin diseases among adults. Itch is a common, disabling skin symptom. The aim was to describe negative life events associated with current itch and to analyze the impact of number of negative life events on symptoms of itch, controlling for possible confounders. This school-based longitudinal survey was conducted among 15 and 18 years old high-school students in Oslo, Norway. From a baseline cohort of 3811 students, 2489 (65%) participants were followed-up after three years later. They completed questionnaires at baseline and follow-up. Current itch was measured with a validated instrument asking for symptoms on a four point Likert scale at follow-up. More girls than boys reported itch. There were no gender differences in number of negative life events. Death among close relative/friend was the most common negative life event among boys and girls. All negative life experiences before 15 years of age were statistically significantly associated with itch, but after 15 years only half of the negative life events were associated with itch. The bivariate association between number of negative life events and itch was statistically significant, and only when adjusting for mental distress at baseline there was a considerable drop in the Odds Ratio. There is a clear association between number of negative life events at baseline and itch at follow-up three years later among adolescents. It is therefore important to discuss possible adverse experiences with adolescents presenting with severe symptoms of itch. Copyright © 2011 Elsevier Inc. All rights reserved.

Negative differential resistance in GaN tunneling hot electron transistors

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

Yang, Zhichao; Nath, Digbijoy; Rajan, Siddharth

Room temperature negative differential resistance is demonstrated in a unipolar GaN-based tunneling hot electron transistor. Such a device employs tunnel-injected electrons to vary the electron energy and change the fraction of reflected electrons, and shows repeatable negative differential resistance with a peak to valley current ratio of 7.2. The device was stable when biased in the negative resistance regime and tunable by changing collector bias. Good repeatability and double-sweep characteristics at room temperature show the potential of such device for high frequency oscillators based on quasi-ballistic transport.

Atomic-Monolayer Two-Dimensional Lateral Quasi-Heterojunction Bipolar Transistors with Resonant Tunneling Phenomenon.

PubMed

Lin, Che-Yu; Zhu, Xiaodan; Tsai, Shin-Hung; Tsai, Shiao-Po; Lei, Sidong; Shi, Yumeng; Li, Lain-Jong; Huang, Shyh-Jer; Wu, Wen-Fa; Yeh, Wen-Kuan; Su, Yan-Kuin; Wang, Kang L; Lan, Yann-Wen

2017-11-28

High-frequency operation with ultrathin, lightweight, and extremely flexible semiconducting electronics is highly desirable for the development of mobile devices, wearable electronic systems, and defense technologies. In this work, the experimental observation of quasi-heterojunction bipolar transistors utilizing a monolayer of the lateral WSe 2 -MoS 2 junctions as the conducting p-n channel is demonstrated. Both lateral n-p-n and p-n-p heterojunction bipolar transistors are fabricated to exhibit the output characteristics and current gain. A maximum common-emitter current gain of around 3 is obtained in our prototype two-dimensional quasi-heterojunction bipolar transistors. Interestingly, we also observe the negative differential resistance in the electrical characteristics. A potential mechanism is that the negative differential resistance is induced by resonant tunneling phenomenon due to the formation of quantum well under applying high bias voltages. Our results open the door to two-dimensional materials for high-frequency, high-speed, high-density, and flexible electronics.

Self-evaluative and emotion processes linked with brooding rumination among adolescents.

PubMed

Burwell, Rebecca A

2015-06-01

Rumination has been linked with a number of deleterious outcomes, though relatively little is known about self-evaluative and emotion processes by which it develops. The current investigation uses a prospective, longitudinal design and self-report measures to examine the role of contingent self-worth, perfectionism, negative emotion beliefs, and suppression of negative emotion in predicting the development of brooding and reflective forms of rumination among 168 adolescents (98 girls, 79.6% European-American) undergoing the transition to high school (Mage = 13.58). Results of structural equation modeling indicate that self-evaluative vulnerability (i.e., self-worth contingencies, perfectionism) and negative emotion beliefs, but not the suppression of negative emotion, predict brooding (but not reflective) rumination. The current study demonstrates how brooding is intertwined with views of self and core assumptions about emotion. Copyright © 2015 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.

A tunable acoustic metamaterial with double-negativity driven by electromagnets

PubMed Central

Chen, Zhe; Xue, Cheng; Fan, Li; Zhang, Shu-yi; Li, Xiao-juan; Zhang, Hui; Ding, Jin

2016-01-01

With the advance of the research on acoustic metamaterials, the limits of passive metamaterials have been observed, which prompts the studies concerning actively tunable metamaterials with adjustable characteristic frequency bands. In this work, we present a tunable acoustic metamaterial with double-negativity composed of periodical membranes and side holes, in which the double-negativity pass band can be controlled by an external direct-current voltage. The tension and stiffness of the periodically arranged membranes are actively controlled by electromagnets producing additional stresses, and thus, the transmission and phase velocity of the metamaterial can be adjusted by the driving voltage of the electromagnets. It is demonstrated that a tiny direct-current voltage of 6V can arise a shift of double-negativity pass band by 40% bandwidth, which exhibits that it is an easily controlled and highly tunable acoustic metamaterial, and furthermore, the metamaterial marginally causes electromagnetic interference to the surroundings. PMID:27443196

Extension of high poloidal beta scenario in DIII-D to lower q95 for steady state fusion reactor

NASA Astrophysics Data System (ADS)

Huang, J.; Gong, X.; Qian, J.; Ding, S.; Ren, Q.; Guo, W.; Pan, C.; Li, G.; Xia, T.; Garofalo, A.; Lao, L.; Hyatt, A.; Ferron, J.; Collins, C.; Lin, D.; McKee, G.; Rhode, T.; McClenaghan, J.; Holcomb, C.; Cui, L.; Heidbrink, W.; Zhu, Y.; Diiid Team; East Team

2017-10-01

DIII-D/EAST joint experiments have improved the high poloidal beta scenario with sustained large-radius internal transport barrier (ITB) extended to high plasma current Ip 1MA with q95 6.0. Slight off-axis NBCD is applied to obtain broader current density profile, ITBs can now be sustained below the previously observed βp threshold with excellent confinement (H98y2 1.8). The scenario also exhibits a local negative shear appearing with q increased at rho 0.4, which helps ITB formation and sustainment. This confirms TGLF prediction that negative magnetic shear can help recover ITB and achieve high confinement with reduced q95. Detailed analysis shows that the Shafranov shift and q profile is critical in the ITB formation at high βp regime. Supported in part by National Magnetic Confinement Fusion Program of China 2015GB102000, 2015GB110005, and US Department of Energy under DE-FC02-04ER54698.

The impact of non-concordant self-report of substance use in clinical trials research.

PubMed

Clark, C Brendan; Zyambo, Cosmas M; Li, Ye; Cropsey, Karen L

2016-07-01

Studies comparing self-report substance use data to biochemical verification generally demonstrate high rates of concordance. We argue that these rates are due to the relatively high true negative rate in the general population, and high degree of honestly in treatment seeking individuals. We hypothesized that high risk individuals not seeking treatment would demonstrate low concordance and a high false negative rate of self-reported substance use. A sample of 500 individuals from a smoking cessation clinical trial was assessed over 1 year. Assessments included semi-structured interviews, questionnaires (e.g. Addiction Severity Index, etc.), and urine drug screen assays (UDS). Generalized estimating equations (GEEs) were used to predict false negative reports for various substances across the study and determine the influence of substance use on the primary study outcome of smoking cessation. Participants demonstrated high false negative rates in reporting substances use, and the false negative rates increased as the study progressed. Established predictors of false negatives generalized to the current sample. High concordance and low false negative rates were found in self-report of nicotine use. A small but significant relationship was found in for effect of biochemically verified substance use on smoking cessation. Biochemical verification of substance use is needed in high risk populations involved in studies not directly related to the treatment of substance use, especially in populations with high threat of stigmatization. Testing should continue through the time period of the study for maximal identification of substance use. Copyright © 2016 Elsevier Ltd. All rights reserved.

Tunable electron heating induced giant magnetoresistance in the high mobility GaAs/AlGaAs 2D electron system

DOE PAGES

Wang, Zhuo; Samaraweera, R. L.; Reichl, C.; ...

2016-12-07

Electron-heating induced by a tunable, supplementary dc-current (I dc) helps to vary the observed magnetoresistance in the high mobility GaAs/AlGaAs 2D electron system. The magnetoresistance at B = 0.3 T is shown to progressively change from positive to negative with increasing Idc, yielding negative giant-magnetoresistance at the lowest temperature and highest I dc. A two-term Drude model successfully fits the data at all Idc and T. The results indicate that carrier heating modifies a conductivity correction σ 1, which undergoes sign reversal from positive to negative with increasing I dc, and this is responsible for the observed crossover from positive-more » to negative- magnetoresistance, respectively, at the highest B.« less

Brand Suicide? Memory and Liking of Negative Brand Names

PubMed Central

Guest, Duncan; Estes, Zachary; Gibbert, Michael; Mazursky, David

2016-01-01

Negative brand names are surprisingly common in the marketplace (e.g., Poison perfume; Hell pizza, and Monster energy drink), yet their effects on consumer behavior are currently unknown. Three studies investigated the effects of negative brand name valence on brand name memory and liking of a branded product. Study 1 demonstrates that relative to non-negative brand names, negative brand names and their associated logos are better recognised. Studies 2 and 3 demonstrate that negative valence of a brand name tends to have a detrimental influence on product evaluation with evaluations worsening as negative valence increases. However, evaluation is also dependent on brand name arousal, with high arousal brand names resulting in more positive evaluations, such that moderately negative brand names are equally as attractive as some non-negative brand names. Study 3 shows evidence for affective habituation, whereby the effects of negative valence reduce with repeated exposures to some classes of negative brand name. PMID:27023872

Brand Suicide? Memory and Liking of Negative Brand Names.

PubMed

Guest, Duncan; Estes, Zachary; Gibbert, Michael; Mazursky, David

2016-01-01

Negative brand names are surprisingly common in the marketplace (e.g., Poison perfume; Hell pizza, and Monster energy drink), yet their effects on consumer behavior are currently unknown. Three studies investigated the effects of negative brand name valence on brand name memory and liking of a branded product. Study 1 demonstrates that relative to non-negative brand names, negative brand names and their associated logos are better recognised. Studies 2 and 3 demonstrate that negative valence of a brand name tends to have a detrimental influence on product evaluation with evaluations worsening as negative valence increases. However, evaluation is also dependent on brand name arousal, with high arousal brand names resulting in more positive evaluations, such that moderately negative brand names are equally as attractive as some non-negative brand names. Study 3 shows evidence for affective habituation, whereby the effects of negative valence reduce with repeated exposures to some classes of negative brand name.

High current DC negative ion source for cyclotron.

PubMed

Etoh, H; Onai, M; Aoki, Y; Mitsubori, H; Arakawa, Y; Sakuraba, J; Kato, T; Mitsumoto, T; Hiasa, T; Yajima, S; Shibata, T; Hatayama, A; Okumura, Y

2016-02-01

A filament driven multi-cusp negative ion source has been developed for proton cyclotrons in medical applications. In Cs-free operation, continuous H(-) beam of 10 mA and D(-) beam of 3.3 mA were obtained stably at an arc-discharge power of 3 kW and 2.4 kW, respectively. In Cs-seeded operation, H(-) beam current reached 22 mA at a lower arc power of 2.6 kW with less co-extracted electron current. The optimum gas flow rate, which gives the highest H(-) current, was 15 sccm in the Cs-free operation, while it decreased to 4 sccm in the Cs-seeded operation. The relationship between H(-) production and the design/operating parameters has been also investigated by a numerical study with KEIO-MARC code, which gives a reasonable explanation to the experimental results of the H(-) current dependence on the arc power.

Current-voltage characteristics of C70 solid near Meyer-Neldel temperature

NASA Astrophysics Data System (ADS)

Onishi, Koichi; Sezaimaru, Kouki; Nakashima, Fumihiro; Sun, Yong; Kirimoto, Kenta; Sakaino, Masamichi; Kanemitsu, Shigeru

2017-06-01

The current-voltage characteristics of the C70 solid with hexagonal closed-packed structures were measured in the temperature range of 250-450 K. The current-voltage characteristics can be described as a temporary expedient by a cubic polynomial of the voltage, i = a v 3 + b v 2 + c v + d . Moreover, the Meyer-Neldel temperature of the C70 solid was confirmed to be 310 K, at which a linear relationship between the current and voltage was observed. Also, at temperatures below the Meyer-Neldel temperature, the current increases with increasing voltage. On the other hand, at temperatures above the Meyer-Neldel temperature a negative differential conductivity effect was observed at high voltage side. The negative differential conductivity was related to the electric field and temperature effects on the mobility of charge carrier, which involve two variations in the carrier concentration and the activation energy for carrier hopping transport.

Risk score predicts high-grade prostate cancer in DNA-methylation positive, histopathologically negative biopsies.

PubMed

Van Neste, Leander; Partin, Alan W; Stewart, Grant D; Epstein, Jonathan I; Harrison, David J; Van Criekinge, Wim

2016-09-01

Prostate cancer (PCa) diagnosis is challenging because efforts for effective, timely treatment of men with significant cancer typically result in over-diagnosis and repeat biopsies. The presence or absence of epigenetic aberrations, more specifically DNA-methylation of GSTP1, RASSF1, and APC in histopathologically negative prostate core biopsies has resulted in an increased negative predictive value (NPV) of ∼90% and thus could lead to a reduction of unnecessary repeat biopsies. Here, it is investigated whether, in methylation-positive men, DNA-methylation intensities could help to identify those men harboring high-grade (Gleason score ≥7) PCa, resulting in an improved positive predictive value. Two cohorts, consisting of men with histopathologically negative index biopsies, followed by a positive or negative repeat biopsy, were combined. EpiScore, a methylation intensity algorithm was developed in methylation-positive men, using area under the curve of the receiver operating characteristic as metric for performance. Next, a risk score was developed combining EpiScore with traditional clinical risk factors to further improve the identification of high-grade (Gleason Score ≥7) cancer. Compared to other risk factors, detection of DNA-methylation in histopathologically negative biopsies was the most significant and important predictor of high-grade cancer, resulting in a NPV of 96%. In methylation-positive men, EpiScore was significantly higher for those with high-grade cancer detected upon repeat biopsy, compared to those with either no or low-grade cancer. The risk score resulted in further improvement of patient risk stratification and was a significantly better predictor compared to currently used metrics as PSA and the prostate cancer prevention trial (PCPT) risk calculator (RC). A decision curve analysis indicated strong clinical utility for the risk score as decision-making tool for repeat biopsy. Low DNA-methylation levels in PCa-negative biopsies led to a NPV of 96% for high-grade cancer. The risk score, comprising DNA-methylation intensity and traditional clinical risk factors, improved the identification of men with high-grade cancer, with a maximum avoidance of unnecessary repeat biopsies. This risk score resulted in better patient risk stratification and significantly outperformed current risk prediction models such as PCPTRC and PSA. The risk score could help to identify patients with histopathologically negative biopsies harboring high-grade PCa. Prostate 76:1078-1087, 2016. © 2016 The Authors. The Prostate Published by Wiley Periodicals, Inc. © 2016 The Authors. The Prostate Published by Wiley Periodicals, Inc.

Feline mammary basal-like adenocarcinomas: a potential model for human triple-negative breast cancer (TNBC) with basal-like subtype.

PubMed

Wiese, David A; Thaiwong, Tuddow; Yuzbasiyan-Gurkan, Vilma; Kiupel, Matti

2013-09-03

Breast cancer is one of the leading causes of cancer deaths. Triple-negative breast cancer (TNBC), an immunophenotype defined by the absence of immunolabeling for estrogen receptor (ER), progesterone receptor (PR) and HER2 protein, has a highly aggressive behavior. A subpopulation of TNBCs exhibit a basal-like morphology with immunohistochemical positivity for cytokeratins 5/6 (CK5/6) and/or epidermal growth factor receptor (EGFR), and have a high incidence of BRCA (breast cancer susceptibility) mutations. Feline mammary adenocarcinomas (FMAs) are highly malignant and share a similar basal-like subtype. The purpose of this study was to classify FMAs according to the current human classification of breast cancer that includes evaluation of ER, PR and HER2 status and expression of basal CK 5/6 and EGFR. Furthermore, we selected triple negative, basal-like FMAs to screen for BRCA mutations similar to those described in human TNBC. Twenty four FMAs were classified according to the current human histologic breast cancer classification including immunohistochemistry (IHC) for ER, PR HER2, CK5/6 and EGFR. Genetic alteration and loss of heterozygosity of BRCA1 and BRCA2 genes were analyzed in triple negative, basal-like FMAs. IHC for ER, PR and HER2 identified 14 of the 24 (58%) FMAs as a triple negative. Furthermore, 11 of these 14 (79%) triple negative FMAs had a basal-like subtype. However, no genetic abnormalities were detected in BRCA1 and BRCA2 by direct sequencing and loss of heterozygosity analysis. FMAs are highly aggressive neoplasms that are commonly triple negative and exhibit a basal-like morphology. This is similar to human TNBC that are also commonly classified as a basal-like subtype. While sequencing of a select number of triple negative, basal-like FMAs and testing for loss of heterozygosity of BRCA1 and BRCA2 did not identify mutations similar to those described in human TNBC, further in-depth evaluation is required to elucidate a potential role of BRCA in the tumorigenesis of triple negative, basal-like FMAs. The strong similarities in clinical behavior, morphology and IHC phenotype suggest that triple negative, basal-like FMAs may be a suitable spontaneous animal model for studying novel therapeutic approaches against human basal-like TNBC.

Transport modeling of the DIII-D high $${{\\beta}_{p}}$$ scenario and extrapolations to ITER steady-state operation

DOE PAGES

McClenaghan, Joseph; Garofalo, Andrea M.; Meneghini, Orso; ...

2017-08-03

In this study, transport modeling of a proposed ITER steady-state scenario based on DIII-D high poloidal-beta (more » $${{\\beta}_{p}}$$ ) discharges finds that ITB formation can occur with either sufficient rotation or a negative central shear q-profile. The high $${{\\beta}_{p}}$$ scenario is characterized by a large bootstrap current fraction (80%) which reduces the demands on the external current drive, and a large radius internal transport barrier which is associated with excellent normalized confinement. Modeling predictions of the electron transport in the high $${{\\beta}_{p}}$$ scenario improve as $${{q}_{95}}$$ approaches levels similar to typical existing models of ITER steady-state and the ion transport is turbulence dominated. Typical temperature and density profiles from the non-inductive high $${{\\beta}_{p}}$$ scenario on DIII-D are scaled according to 0D modeling predictions of the requirements for achieving a $Q=5$ steady-state fusion gain in ITER with 'day one' heating and current drive capabilities. Then, TGLF turbulence modeling is carried out under systematic variations of the toroidal rotation and the core q-profile. A high bootstrap fraction, high $${{\\beta}_{p}}$$ scenario is found to be near an ITB formation threshold, and either strong negative central magnetic shear or rotation in a high bootstrap fraction are found to successfully provide the turbulence suppression required to achieve $Q=5$.« less

Computer modeling of current collection by the CHARGE-2 mother payload

NASA Technical Reports Server (NTRS)

Mandell, M. J.; Lilley, J. R., Jr.; Katz, I.; Neubert, T.; Myers, Neil B.

1990-01-01

The three-dimensional computer codes NASCAP/LEO and POLAR have been used to calculate current collection by the mother payload of the CHARGE-2 rocket under conditions of positive and negative potential up to several hundred volts. For negative bias (ion collection), the calculations lie about 25 percent above the data, indicating that the ions were less dense, colder, or heavier than the input parameters. For positive bias (electron collection), NASCAP/LEO and POLAR calculations show similar agreement with the measurements at the highest altitudes. This agreement indicates that the current is classically magnetically limited, even during electron beam emission. However, the calculated values fall well below the data at lower altitudes. It is suggested that beam-plasma-neutral interactions are responsible for the high values of collected current at altitudes below 240 km.

Principle and experimental investigation of current-driven negative-inductance superconducting quantum interference device

NASA Astrophysics Data System (ADS)

Li, Hao; Liu, Jianshe; Zhang, Yingshan; Cai, Han; Li, Gang; Liu, Qichun; Han, Siyuan; Chen, Wei

2017-03-01

A negative-inductance superconducting quantum interference device (nSQUID) is an adiabatic superconducting logic device with high energy efficiency, and therefore a promising building block for large-scale low-power superconducting computing. However, the principle of the nSQUID is not that straightforward and an nSQUID driven by voltage is vulnerable to common mode noise. We investigate a single nSQUID driven by current instead of voltage, and clarify the principle of the adiabatic transition of the current-driven nSQUID between different states. The basic logic operations of the current-driven nSQUID with proper parameters are simulated by WRspice. The corresponding circuit is fabricated with a 100 A cm-2 Nb-based lift-off process, and the experimental results at low temperature confirm the basic logic operations as a gated buffer.

The impact of negative emotions on self-concept abstraction depends on accessible information processing styles.

PubMed

Isbell, Linda M; Rovenpor, Daniel R; Lair, Elicia C

2016-10-01

Research suggests that anger promotes global, abstract processing whereas sadness and fear promote local, concrete processing (see Schwarz & Clore, 2007 for a review). Contrary to a large and influential body of work suggesting that specific affective experiences are tethered to specific cognitive outcomes, the affect-as-cognitive-feedback account maintains that affective experiences confer positive or negative value on currently dominant processing styles, and thus can lead to either global or local processing (Huntsinger, Isbell, & Clore, 2014). The current work extends this theoretical perspective by investigating the impact of discrete negative emotions on the self-concept. By experimentally manipulating information processing styles and discrete negative emotions that vary in appraisals of certainty, we demonstrate that the impact of discrete negative emotions on the spontaneous self-concept depends on accessible processing styles. When global processing was accessible, individuals in angry (negative, high certainty) states generated more abstract statements about themselves than individuals in either sad (Experiment 1) or fearful (Experiment 2; negative, low certainty) states. When local processing was made accessible, however, the opposite pattern emerged, whereby individuals in angry states generated fewer abstract statements than individuals in sad or fearful states. Together these studies provide new insights into the mechanisms through which discrete emotions influence cognition. In contrast to theories assuming a dedicated link between emotions and processing styles, these results suggest that discrete emotions provide feedback about accessible ways of thinking, and are consistent with recent evidence suggesting that the impact of affect on cognition is highly context-dependent. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Highly anisotropic magneto-transport and field orientation dependent oscillations in aligned carbon nanotube/epoxy composites

NASA Astrophysics Data System (ADS)

Wells, Brian; Kumar, Raj; Reynolds, C. Lewis; Peters, Kara; Bradford, Philip D.

2017-12-01

Carbon nanotubes (CNTs) have been widely investigated as additive materials for composites with potential applications in electronic devices due to their extremely large electrical conductivity and current density. Here, highly aligned CNT composite films were created using a sequential layering fabrication technique. The degree of CNT alignment leads to anisotropic resistance values which varies >400× in orthogonal directions. Similarly, the magnetoresistance (MR) of the CNT composite differs depending upon the relative direction of current and the applied magnetic field. A suppression of negative to positive MR crossover was also observed. More importantly, an overall positive magnetoresistance behavior with localized +/- oscillations was discovered at low fields which persists up to room temperature when the current (I) and in-plane magnetic field (B) were parallel to the axis of CNT (B∥I∥CNT), which is consistent with Aharonov-Bohm oscillations in our CNT/epoxy composites. When the current, applied magnetic field, and nanotube axis are aligned, the in-plane MR is positive instead of negative as observed for all other field, current, and tube orientations. Here, we provide in-depth analysis of the conduction mechanism and anisotropy in the magneto-transport properties of these aligned CNT-epoxy composites.

Impulsivity and temporal frame: Reducing frequency of snacking by highlighting immediate health benefits.

PubMed

Pavey, Louisa; Churchill, Sue

2017-08-01

The current study aimed to examine the effect of giving temporally framed health information regarding either the immediate or long-term health consequences of consuming high-calorie snacks, for people with high Negative Urgency (a dimension of impulsivity), and for those primed with impulsivity. We expected that for participants with high Negative Urgency, and those primed with impulsivity, information which detailed the immediate health benefits of avoiding snack consumption would be more effective than information which detailed long-term health benefits. Participants (N=110) completed a measure of Negative Urgency, reported their snacking frequency over the previous seven days, and completed either an impulsivity or neutral prime task. Following this, they read information detailing either the immediate or long-term health benefits of avoiding high-calorie snacks. High-calorie snack consumption was reported 7days later. The results showed a significant three-way interaction between Negative Urgency, prime task, and temporal frame. Participants who were primed with impulsivity and those high in Negative Urgency showed a greater reduction in snacking frequency after being given information about the immediate vs. long-term health benefits of snacking. The results suggest that the immediacy of health consequences should be considered when designing health information to reduce impulsive snacking behaviour. Copyright © 2017. Published by Elsevier Ltd.

Specific characteristics of negative corona currents generated in short point-plane gap

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

Li, Zhen; Zhang, Bo; He, Jinliang

The Trichel pulse is a typical kind of negative corona current observed in electronegative gases with a highly regular form. The characteristics of the Trichel pulse, such as the repetition frequency, the amplitude of each pulse, and the mean current, are dependent on different discharge conditions. Quite many scholars have studied the mean current and the current-voltage characteristic of Trichel pulses, yet the specific characteristics of the pulses have barely been investigated. In this paper, a series of experiments were carried out in a short point-to-plane discharge gap to investigate the detailed characteristics of Trichel pulses. After numerical fitting ofmore » the experiment results was performed, a new set of empirical formulas were derived to predict the specific characteristics of the negative corona current under different conditions. Different from existing literature, this paper uses as variables the average electric field intensity and the corona inception field intensity which is independent of the gap spacing in the empirical formulas. In the experiments, an inverse correlation between amplitude and repetition frequency of the pulses was observed. Based on the investigation of the remaining space charge in the discharge gap, this correlation is theoretically proved to be caused by the influence of space charges.« less

Current paranoid thinking in patients with delusions: the presence of cognitive-affective biases.

PubMed

Freeman, Daniel; Dunn, Graham; Fowler, David; Bebbington, Paul; Kuipers, Elizabeth; Emsley, Richard; Jolley, Suzanne; Garety, Philippa

2013-11-01

There has been renewed interest in the influence of affect on psychosis. Psychological research on persecutory delusions ascribes a prominent role to cognitive processes related to negative affect: anxiety leads to the anticipation of threat within paranoia; depressive negative ideas about the self create a sense of vulnerability in which paranoid thoughts flourish; and self-consciousness enhances feelings of the self as a target. The objective of this study was to examine such affective processes in relation to state paranoia in patients with delusions. 130 patients with delusions in the context of a nonaffective psychosis diagnosis (predominately schizophrenia) were assessed for contemporaneous levels of persecutory ideation on 5 visual analog scales. Measures were taken of anxiety, depression, threat anticipation, interpretation of ambiguity, self-focus, and negative ideas about the self. Of the patients, 85% report paranoid thinking at testing. Symptoms of anxiety and depression were highly prevalent. Current paranoid thinking was associated with anxiety, depression, greater anticipation of threat events, negative interpretations of ambiguous events, a self-focused cognitive style, and negative ideas about the self. The study provides a clear demonstration that a range of emotion-related cognitive biases, each of which could plausibly maintain delusions, are associated with current paranoid thinking in patients with psychosis. We identified biases both in the contents of cognition and in the processing of information. Links between affect and psychosis are central to the understanding of schizophrenia. We conclude that treatment of emotional dysfunction should lead to reductions in current psychotic experiences.

Features of Upward Positive Leaders Initiated From Towers in Natural Cloud-to-Ground Lightning Based on Simultaneous High-Speed Videos, Measured Currents, and Electric Fields

NASA Astrophysics Data System (ADS)

Visacro, Silverio; Guimaraes, Miguel; Murta Vale, Maria Helena

2017-12-01

Original simultaneous records of currents, close electric field, and high-speed videos of natural negative cloud-to-ground lightning striking the tower of Morro do Cachimbo Station are used to reveal typical features of upward positive leaders before the attachment, including their initiation and mode of propagation. According to the results, upward positive leaders initiate some hundreds of microseconds prior to the return stroke, while a continuous uprising current of about 4 A and superimposed pulses of a few tens amperes flow along the tower. Upon leader initiation, the electric field measured 50 m away from the tower at ground level is about 60 kV/m. The corresponding average field roughly estimated 0.5 m above the tower top is higher than 0.55 MV/m. As in laboratory experiments, the common propagation mode of upward positive leaders is developing continuously, without steps, from their initiation. Unlike downward negative leaders, upward positive leaders typically do not branch off, though they can bifurcate under the effect of a downward negative leader's secondary branch approaching their lateral surface. The upward positive leader's estimated average two-dimensional propagation speed, in the range of 0.06 × 106 to 0.16 × 106 m/s, has the same order of magnitude as that of downward negative leaders. Apparently, the speed tends to increase just before attachment.

Predictors of Biased Self-perception in Individuals with High Social Anxiety: The Effect of Self-consciousness in the Private and Public Self Domains.

PubMed

Nordahl, Henrik; Plummer, Alice; Wells, Adrian

2017-01-01

"Biased self-perception," the tendency to perceive one's social performance as more negative than observers do, is characteristic of socially anxious individuals. Self-attention processes are hypothesised to underlie biased self-perception, however, different models emphasise different aspects of self-attention, with attention to the public aspects of the self being prominent. The current study aimed to investigate the relative contribution of two types of dispositional self-attention; public- and private self-consciousness to biased self-perception in a high ( n = 48) versus a low ( n = 48) social anxiety group undergoing an interaction task. The main finding was that private self-consciousness explained substantial and unique variance in biased negative self-perception in individuals with high social anxiety, while public self-consciousness did not. This relationship was independent of increments in state anxiety. Private self-consciousness appeared to have a specific association with bias related to overestimation of negative social performance rather than underestimation of positive social performance. The implication of this finding is that current treatment models of Social anxiety disorder might include broader aspects of self-focused attention, especially in the context of formulating self-evaluation biases.

Cognitive vulnerability to depression in young people in secure accommodation: the influence of ethnicity and current suicidal ideation.

PubMed

Woolgar, Matthew; Tranah, Troy

2010-10-01

Young people in secure accommodation are at high risk of depression and self-harm. This study investigates the relationship between depressive symptoms, negative self-schemas and the cognitive vulnerability to depression in 38 young people in secure accommodation. The impact of a) current suicidal ideation and b) a previous history of self-harm behaviour on latent negative self-schemas was examined using a mood induction task. The low mood condition indicated these young people had a latent cognitive vulnerability to depression. However, this vulnerability was exacerbated in the context of current suicidal ideation but not by a history of self-harm behaviours. An unexpected finding was the negative self-schemas of young people from ethnic minority backgrounds were particularly susceptible to the mood induction. The findings are discussed both in terms of the cognitive vulnerabilities of adolescents detained in secure accommodation and the role of participant characteristics on the validity of mood induction studies in adolescence.

A Unified Model of Cloud-to-Ground Lightning Stroke

NASA Astrophysics Data System (ADS)

Nag, A.; Rakov, V. A.

2014-12-01

The first stroke in a cloud-to-ground lightning discharge is thought to follow (or be initiated by) the preliminary breakdown process which often produces a train of relatively large microsecond-scale electric field pulses. This process is poorly understood and rarely modeled. Each lightning stroke is composed of a downward leader process and an upward return-stroke process, which are usually modeled separately. We present a unified engineering model for computing the electric field produced by a sequence of preliminary breakdown, stepped leader, and return stroke processes, serving to transport negative charge to ground. We assume that a negatively-charged channel extends downward in a stepped fashion through the relatively-high-field region between the main negative and lower positive charge centers and then through the relatively-low-field region below the lower positive charge center. A relatively-high-field region is also assumed to exist near ground. The preliminary breakdown pulse train is assumed to be generated when the negatively-charged channel interacts with the lower positive charge region. At each step, an equivalent current source is activated at the lower extremity of the channel, resulting in a step current wave that propagates upward along the channel. The leader deposits net negative charge onto the channel. Once the stepped leader attaches to ground (upward connecting leader is presently neglected), an upward-propagating return stroke is initiated, which neutralizes the charge deposited by the leader along the channel. We examine the effect of various model parameters, such as step length and current propagation speed, on model-predicted electric fields. We also compare the computed fields with pertinent measurements available in the literature.

Psychosocial treatments for negative symptoms in schizophrenia: Current practices and future directions

PubMed Central

Elis, Ori; Caponigro, Janelle M.; Kring, Ann M.

2014-01-01

Schizophrenia can be a chronic and debilitating psychiatric disorder. Though advancements have been made in the psychosocial treatment of some symptoms of schizophrenia, people with schizophrenia often continue to experience some level of symptoms, particularly negative symptoms, throughout their lives. Because negative symptoms are associated with poor functioning and quality of life, the treatment of negative symptoms is a high priority for intervention development. However, current psychosocial treatments primarily focus on the reduction of positive symptoms with comparatively few studies investigating the efficacy of psychosocial treatments for negative symptoms. In this article, we review and evaluate the existing literature on three categories of psychosocial treatments – cognitive behavioral therapy (CBT), social skills training (SST), and combined treatment interventions – and their impact on the negative symptoms of schizophrenia. Of the interventions reviewed, CBT and SST appear to have the most empirical support, with some evidence suggesting that CBT is associated with maintenance of negative symptom improvement beyond six months after treatment. It remains unclear if a combined treatment approach provides improvements above and beyond those associated with each individual treatment modality. Although psychosocial treatments show promise for the treatment of negative symptoms, there are many unanswered questions about how best to intervene. We conclude with a general discussion of these unanswered questions, future directions and methodological considerations, and suggestions for the further development of negative symptom interventions. PMID:23988452

Effect of workplace incivility on end-of-work negative affect: examining individual and organizational moderators in a daily diary study.

PubMed

Zhou, Zhiqing E; Yan, Yu; Che, Xin Xuan; Meier, Laurenz L

2015-01-01

Although previous studies have linked workplace incivility with various negative outcomes, they mainly focused on the long-term effects of chronic exposure to workplace incivility, whereas targets' short-term reactions to incivility episodes have been largely neglected. Using a daily diary design, the current study examined effects of daily workplace incivility on end-of-work negative affect and explored potential individual and organizational moderators. Data collected from 76 full-time employees across 10 consecutive working days revealed that daily workplace incivility positively predicted end-of-work negative affect while controlling for before-work negative affect. Further, the relationship was stronger for people with low emotional stability, high hostile attribution bias, external locus of control, and people experiencing low chronic workload and more chronic organizational constraints, as compared with people with high emotional stability, low hostile attribution bias, internal locus of control, and people experiencing high chronic workload and fewer chronic organizational constraints, respectively. (PsycINFO Database Record (c) 2014 APA, all rights reserved). PsycINFO Database Record (c) 2014 APA, all rights reserved.

Evidence that COMT genotype and proline interact on negative-symptom outcomes in schizophrenia and bipolar disorder.

PubMed

Clelland, C L; Drouet, V; Rilett, K C; Smeed, J A; Nadrich, R H; Rajparia, A; Read, L L; Clelland, J D

2016-09-13

Elevated peripheral proline is associated with psychiatric disorders, and there is evidence that proline is a neuromodulator. The proline dehydrogenase (PRODH) gene, which encodes the enzyme that catalyzes proline catabolism, maps to human chromosome 22q11.2, a region conferring risk of schizophrenia. In the Prodh-null mouse, an interaction between elevated peripheral proline and another 22q11.2 gene, catechol-O-methyltransferase (COMT), on neurotransmission and behavior has been reported. We explored the relationship between fasting plasma proline levels and COMT Val(158)Met genotype on symptoms (positive, negative and total) in schizophrenia patients. In an exploratory study we also examined symptom change in patients with bipolar disorder. There was a significant interaction between peripheral proline and COMT on negative symptoms in schizophrenia (P<0.0001, n=95). In COMT Val/Val patients, high proline was associated with low Scale for the Assessment of Negative Symptom (SANS) scores. In contrast, high proline was associated with high SANS scores in patients carrying a Met allele. The relationship between proline and COMT also appears to modify negative symptoms across psychiatric illness. In bipolar disorder, a significant interaction was also observed on negative-symptom change (P=0.007, n=43). Negative symptoms are intractable and largely unaddressed by current medications. These data indicate a significant interaction between peripheral proline and COMT genotype, influencing negative symptoms in schizophrenia and bipolar disorder. That high proline has converse effects on symptoms by COMT genotype, may have implications for therapeutic decisions.

First results from negative ion beam extraction in ROBIN in surface mode

NASA Astrophysics Data System (ADS)

Pandya, Kaushal; Gahlaut, Agrajit; Yadav, Ratnakar K.; Bhuyan, Manas; Bandyopadhyay, Mainak; Das, B. K.; Bharathi, P.; Vupugalla, Mahesh; Parmar, K. G.; Tyagi, Himanshu; Patel, Kartik; Bhagora, Jignesh; Mistri, Hiren; Prajapati, Bhavesh; Pandey, Ravi; Chakraborty, Arun. K.

2017-08-01

ROBIN, the first step in the Indian R&D program on negative ion beams has reached an important milestone, with the production of negative ions in the surface conversion mode through Cesium (Cs) vapor injection into the source. In the present set-up, negative hydrogen ion beam extraction is effected through an extraction area of ˜73.38 cm2 (146 apertures of 8mm diameter). The three grid electrostatic accelerator system of ROBIN is fed by high voltage DC power supplies (Extraction Power Supply System: 11kV, 35A and Acceleration Power Supply System: 35kV, 15A). Though, a considerable reduction of co-extracted electron current is usually observed during surface mode operation, in order to increase the negative ion current, various other parameters such as plasma grid temperature, plasma grid bias, extraction to acceleration voltage ratio, impurity control and Cs recycling need to be optimized. In the present experiments, to control and to understand the impurity behavior, a Cryopump (14,000 l/s for Hydrogen) is installed along with a Residual Gas Analyzer (RGA). To characterize the source plasma, two sets of Langmuir probes are inserted through the diagnostic flange ports available at the extraction plane. To characterize the beam properties, thermal differential calorimeter, Doppler Shift Spectroscopy and electrical current measurements are implemented in ROBIN. In the present set up, all the negative ion beam extraction experiments have been performed by varying different experimental parameters e.g. RF power (30-70 kW), source operational pressure (0.3 - 0.6Pa), plasma grid bias voltage, extraction & acceleration voltage combination etc. The experiments in surface mode operation is resulted a reduction of co-extracted electron current having electron to ion ratio (e/i) ˜2 whereas the extracted negative ion current density was increased. However, further increase in negative ion current density is expected to be improved after a systematic optimization of the operational parameters and Cs conditioning of the source. It was also found out that a better performance of ROBIN is achieved in the pressure range: 0.5-0.6 Pa. In this paper, the preliminary results on parametric study of ROBIN operation and beam optimization in surface mode are discussed.

Efficient spin-filter and negative differential resistance behaviors in FeN4 embedded graphene nanoribbon device

NASA Astrophysics Data System (ADS)

Liu, N.; Liu, J. B.; Yao, K. L.; Ni, Y.; Wang, S. L.

2016-03-01

In this paper, we propose a new device of spintronics by embedding two FeN4 molecules into armchair graphene nanoribbon and sandwiching them between N-doped graphene nanoribbon electrodes. Our first-principle quantum transport calculations show that the device is a perfect spin filter with high spin-polarizations both in parallel configuration (PC) and antiparallel configuration (APC). Moreover, negative differential resistance phenomena are obtained for the spin-down current in PC, and the spin-up and spin-down currents in APC. These transport properties are explained by the bias-dependent evolution of molecular orbitals and the transmission spectra.

"El lado oscuro": "the dark side" of social capital in Mexican American heroin using men.

PubMed

Flores, David V; Torres, Luis R; Torres-Vigil, Isabel; Ren, Yi; Haider, Ali; Bordnick, Patrick S

2013-01-01

This article describes social capital in a cohort of 227 Mexican American men who are long-term injection heroin users. Social capital scores for current and former users were similar, suggesting equal absolute values of capital, but associated with illicit activities in current users and with cessation efforts in former users. Stable drug-using relationships provided high negative capital, whereas conventional relationships provided positive capital. Thus, social capital functions dichotomously in positive and negative contextualized roles. This study provides an alternative understanding of the dynamic interactions between individuals, environment, and drug abuse and can inform prevention and treatment interventions for an important demographic group.

Physical origins of current and temperature controlled negative differential resistances in NbO 2

DOE PAGES

Kumar, Suhas; Wang, Ziwen; Davila, Noraica; ...

2017-09-22

Negative differential resistance behavior in oxide memristors, especially those using NbO 2, is gaining renewed interest because of its potential utility in neuromorphic computing. However, there has been a decade-long controversy over whether the negative differential resistance is caused by a relatively low-temperature non-linear transport mechanism or a high-temperature Mott transition. Resolving this issue will enable consistent and robust predictive modeling of this phenomenon for different applications. Here in this paper, we examine NbO 2 memristors that exhibit both a current-controlled and a temperature-controlled negative differential resistance. Through thermal and chemical spectromicroscopy and numerical simulations, we confirm that the formermore » is caused by a ~400 K non-linear-transport-driven instability and the latter is caused by the ~1000 K Mott metal-insulator transition, for which the thermal conductance counter-intuitively decreases in the metallic state relative to the insulating state.« less

Ask and you shall receive: desire and receipt of feedback via Facebook predicts disordered eating concerns.

PubMed

Hummel, Alexandra C; Smith, April R

2015-05-01

The current study examined whether certain types of Facebook content (i.e., status updates, comments) relate to eating concerns and attitudes. We examined the effects of seeking and receiving negative feedback via Facebook on disordered eating concerns in a sample of 185 undergraduate students followed for approximately 4 weeks. Results indicated that individuals with a negative feedback seeking style who received a high number of comments on Facebook were more likely to report disordered eating attitudes four weeks later. Additionally, individuals who received extremely negative comments in response to their personally revealing status updates were more likely to report disordered eating concerns four weeks later. Results of the current study provide preliminary evidence that seeking and receiving negative feedback via social networking sites can increase risk for disordered eating attitudes, and suggest that reducing maladaptive social networking usage may be an important target for prevention and intervention efforts aimed at reducing disordered eating attitudes. © 2014 Wiley Periodicals, Inc.

Physical origins of current and temperature controlled negative differential resistances in NbO 2

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

Kumar, Suhas; Wang, Ziwen; Davila, Noraica

Negative differential resistance behavior in oxide memristors, especially those using NbO 2, is gaining renewed interest because of its potential utility in neuromorphic computing. However, there has been a decade-long controversy over whether the negative differential resistance is caused by a relatively low-temperature non-linear transport mechanism or a high-temperature Mott transition. Resolving this issue will enable consistent and robust predictive modeling of this phenomenon for different applications. Here in this paper, we examine NbO 2 memristors that exhibit both a current-controlled and a temperature-controlled negative differential resistance. Through thermal and chemical spectromicroscopy and numerical simulations, we confirm that the formermore » is caused by a ~400 K non-linear-transport-driven instability and the latter is caused by the ~1000 K Mott metal-insulator transition, for which the thermal conductance counter-intuitively decreases in the metallic state relative to the insulating state.« less

Negative differential conductance and super-Poissonian shot noise in single-molecule magnet junctions

PubMed Central

Xue, Hai-Bin; Liang, Jiu-Qing; Liu, Wu-Ming

2015-01-01

Molecular spintroinic device based on a single-molecule magnet is one of the ultimate goals of semiconductor nanofabrication technologies. It is thus necessary to understand the electron transport properties of a single-molecule magnet junction. Here we study the negative differential conductance and super-Poissonian shot noise properties of electron transport through a single-molecule magnet weakly coupled to two electrodes with either one or both of them being ferromagnetic. We predict that the negative differential conductance and super-Poissonian shot noise, which can be tuned by a gate voltage, depend sensitively on the spin polarization of the source and drain electrodes. In particular, the shot noise in the negative differential conductance region can be enhanced or decreased originating from the different formation mechanisms of negative differential conductance. The effective competition between fast and slow transport channels is responsible for the observed negative differential conductance and super-Poissonian shot noise. In addition, we further discuss the skewness and kurtosis properties of transport current in the super-Poissonian shot noise regions. Our findings suggest a tunable negative differential conductance molecular device, and the predicted properties of high-order current cumulants are very interesting for a better understanding of electron transport through single-molecule magnet junctions. PMID:25736094

Negative differential conductance and super-Poissonian shot noise in single-molecule magnet junctions.

PubMed

Xue, Hai-Bin; Liang, Jiu-Qing; Liu, Wu-Ming

2015-03-04

Molecular spintroinic device based on a single-molecule magnet is one of the ultimate goals of semiconductor nanofabrication technologies. It is thus necessary to understand the electron transport properties of a single-molecule magnet junction. Here we study the negative differential conductance and super-Poissonian shot noise properties of electron transport through a single-molecule magnet weakly coupled to two electrodes with either one or both of them being ferromagnetic. We predict that the negative differential conductance and super-Poissonian shot noise, which can be tuned by a gate voltage, depend sensitively on the spin polarization of the source and drain electrodes. In particular, the shot noise in the negative differential conductance region can be enhanced or decreased originating from the different formation mechanisms of negative differential conductance. The effective competition between fast and slow transport channels is responsible for the observed negative differential conductance and super-Poissonian shot noise. In addition, we further discuss the skewness and kurtosis properties of transport current in the super-Poissonian shot noise regions. Our findings suggest a tunable negative differential conductance molecular device, and the predicted properties of high-order current cumulants are very interesting for a better understanding of electron transport through single-molecule magnet junctions.

Elevated Appraisals of the Negative Impact of Naturally Occurring Life Events: A Risk Factor for Depressive and Anxiety Disorders

PubMed Central

Espejo, Emmanuel P.; Hammen, Constance; Brennan, Patricia A.

2012-01-01

The tendency to appraise naturally occurring life events (LEs) as having high negative impact may be a predisposing factor for the development of depression and anxiety disorders. In the current study, appraisals of the negative impact of recent LEs were examined in relationship to depressive and anxiety disorders in a sample of 653 adolescents who were administered diagnostic and life stress interviews at ages 15 and 20. Participants’ appraisals of the negative impact of LEs reported at age 15 were statistically adjusted using investigator-based ratings to control for objective differences across LEs. Higher appraisals of the negative impact of LEs were associated with both past and current depressive and anxiety disorders at age 15 and predicted subsequent first onsets of depressive and anxiety disorders occurring between ages 15 and 20. In addition, appraisals of the negative impact of LEs were particularly elevated among those experiencing both a depressive and anxiety disorder over the course of the study. The findings suggest that systematically elevated appraisals of the negative impact of LEs is a predisposing factor for depression and anxiety disorders and may represent a specific risk factor for co-morbid depression and anxiety in mid-adolescence and early adulthood. Keywords: depression; anxiety; stress appraisals; prospective study; PMID:21845380

Reduced impedance and superconductivity of SnAgCu solder alloy at high frequency

NASA Astrophysics Data System (ADS)

Yao, Wei; Basaran, Cemal

2012-10-01

Skin effect of lead-free solder joints is investigated over a wide frequency band. Contrary to common believe that `effective impedance of solder alloys increases with frequency', resistance tends to saturate when frequency reaches a critical value, 10 MHz for SAC solder alloys. Negative surface impedance growth rate is observed when employs square waveform AC current loading at high current density. Further increased frequency causes a dramatic reduction of effective resistance. At 11 MHz with current density of 106 A/cm2, effective resistance of solder alloy drops to near zero value.

Statistical parametric mapping of LORETA using high density EEG and individual MRI: application to mismatch negativities in schizophrenia.

PubMed

Park, Hae-Jeong; Kwon, Jun Soo; Youn, Tak; Pae, Ji Soo; Kim, Jae-Jin; Kim, Myung-Sun; Ha, Kyoo-Seob

2002-11-01

We describe a method for the statistical parametric mapping of low resolution electromagnetic tomography (LORETA) using high-density electroencephalography (EEG) and individual magnetic resonance images (MRI) to investigate the characteristics of the mismatch negativity (MMN) generators in schizophrenia. LORETA, using a realistic head model of the boundary element method derived from the individual anatomy, estimated the current density maps from the scalp topography of the 128-channel EEG. From the current density maps that covered the whole cortical gray matter (up to 20,000 points), volumetric current density images were reconstructed. Intensity normalization of the smoothed current density images was used to reduce the confounding effect of subject specific global activity. After transforming each image into a standard stereotaxic space, we carried out statistical parametric mapping of the normalized current density images. We applied this method to the source localization of MMN in schizophrenia. The MMN generators, produced by a deviant tone of 1,200 Hz (5% of 1,600 trials) under the standard tone of 1,000 Hz, 80 dB binaural stimuli with 300 msec of inter-stimulus interval, were measured in 14 right-handed schizophrenic subjects and 14 age-, gender-, and handedness-matched controls. We found that the schizophrenic group exhibited significant current density reductions of MMN in the left superior temporal gyrus and the left inferior parietal gyrus (P < 0. 0005). This study is the first voxel-by-voxel statistical mapping of current density using individual MRI and high-density EEG. Copyright 2002 Wiley-Liss, Inc.

Theoretical investigation into negative differential resistance characteristics of resonant tunneling diodes based on lattice-matched and polarization-matched AlInN/GaN heterostructures

NASA Astrophysics Data System (ADS)

Rong, Taotao; Yang, Lin-An; Yang, Lin; Hao, Yue

2018-01-01

In this work, we report an investigation of resonant tunneling diodes (RTDs) with lattice-matched and polarization-matched AlInN/GaN heterostructures using the numerical simulation. Compared with the lattice-matched AlInN/GaN RTDs, the RTDs based on polarization-matched AlInN/GaN hetero-structures exhibit symmetrical conduction band profiles due to eliminating the polarization charge discontinuity, which achieve the equivalence of double barrier transmission coefficients, thereby the relatively high driving current, the high symmetry of current density, and the high peak-to-valley current ratio (PVCR) under the condition of the positive and the negative sweeping voltages. Simulations show that the peak current density approaches 1.2 × 107 A/cm2 at the bias voltage of 0.72 V and the PVCR approaches 1.37 at both sweeping voltages. It also shows that under the condition of the same shallow energy level, when the trap density reaches 1 × 1019 cm-3, the polarization-matched RTDs still have acceptable negative differential resistance (NDR) characteristics, while the NDR characteristics of lattice-matched RTDs become irregular. After introducing the deeper energy level of 1 eV into the polarization-matched and lattice-matched RTDs, 60 scans are performed under the same trap density. Simulation results show that the degradation of the polarization-matched RTDs is 22%, while lattice-matched RTDs have a degradation of 55%. It can be found that the polarization-matched RTDs have a greater defect tolerance than the lattice-matched RTDs, which is beneficial to the available manufacture of actual terahertz RTD devices.

Distress intolerance moderation of motivated attention to cannabis and negative stimuli after induced stress among cannabis users: an ERP study.

PubMed

Macatee, Richard J; Okey, Sarah A; Albanese, Brian J; Schmidt, Norman B; Cougle, Jesse R

2018-05-07

Prevalence of cannabis use is increasing, but many regular users do not develop cannabis use disorder (CUD); thus, CUD risk identification among current users is vital for targeted intervention development. Existing data suggest that high distress intolerance (DI), an individual difference reflective of the ability to tolerate negative affect, may be linked to CUD, but no studies have tested possible neurophysiological mechanisms. Increased motivated attentional processing of cannabis and negative emotional stimuli as indexed by neurophysiology [i.e. the late positive potential (LPP)], particularly during acute stress, may contribute to CUD among high DI users. Frequent cannabis users with high (n = 61) and low DI (n = 44) viewed cannabis, negative, and matched neutral images during electroencephalography (EEG) recording before and after a laboratory stressor. Cannabis cue-elicited modulation of the 1000- to 3000-milliseconds LPP was larger in high DI users at post-stressor only, although the effect was only robust in the 1000- to 2000-milliseconds window. Further, modulation magnitude in the high DI group covaried with stress-relief craving and some CUD indices in the 400- to 1000-milliseconds and 1000- to 3000-milliseconds windows, respectively. No significant effects of DI on negative stimuli-elicited LPP modulation were found, although inverse associations with some CUD indices were observed. Finally, exploratory analyses revealed some evidence for DI moderation of the relation between subjective stressor reactivity and negative stimuli-elicited LPP modulation such that greater stressor reactivity was associated with blunted versus enhanced modulation in the high and low DI groups, respectively. Negative and cannabis stimuli-elicited LPP modulation appear to index distinct, CUD-relevant neural processes in high DI cannabis users. © 2018 Society for the Study of Addiction.

Feasibility study of nuclear transmutation by negative muon capture reaction using the PHITS code

NASA Astrophysics Data System (ADS)

Abe, Shin-ichiro; Sato, Tatsuhiko

2016-06-01

Feasibility of nuclear transmutation of fission products in high-level radioactive waste by negative muon capture reaction is investigated using the Particle and Heave Ion Transport code System (PHITS). It is found that about 80 % of stopped negative muons contribute to transmute target nuclide into stable or short-lived nuclide in the case of 135Cs, which is one of the most important nuclide in the transmutation. The simulation result also indicates that the position of transmutation is controllable by changing the energy of incident negative muon. Based on our simulation, it takes approximately 8.5 × 108years to transmute 500 g of 135Cs by negative muon beam with the highest intensity currently available.

Negative Social Evaluative Fears Produce Social Anxiety, Food Intake, and Body Dissatisfaction: Evidence of Similar Mechanisms through Different Pathways

PubMed Central

Levinson, Cheri A.; Rodebaugh, Thomas L.

2014-01-01

Social anxiety and eating disorders are highly comorbid, suggesting there are shared vulnerabilities that underlie the development of these disorders. Two proposed vulnerabilities are fear of negative evaluation and social appearance anxiety (i.e., fear of negative evaluation regarding one's appearance). In the current experimental study (N=160 women) we measured these fears: (a) through a manipulation comparing fear conditions, (b) with trait fears, and (c) state fears. Results indicated that participants in the fear of negative evaluation condition increased food consumption, whereas participants in the social appearance anxiety condition and high in trait social appearance anxiety experienced the highest amounts of body dissatisfaction. Participants in the fear of evaluation and social appearance anxiety conditions experienced elevated social anxiety. These results support the idea that negative evaluation fears are shared vulnerabilities for eating and social anxiety disorders, but that the way these variables exert their effects may lead to disorder specific behaviors. PMID:26504674

Current Paranoid Thinking in Patients With Delusions: The Presence of Cognitive-Affective Biases

PubMed Central

Freeman, Daniel

2013-01-01

Background: There has been renewed interest in the influence of affect on psychosis. Psychological research on persecutory delusions ascribes a prominent role to cognitive processes related to negative affect: anxiety leads to the anticipation of threat within paranoia; depressive negative ideas about the self create a sense of vulnerability in which paranoid thoughts flourish; and self-consciousness enhances feelings of the self as a target. The objective of this study was to examine such affective processes in relation to state paranoia in patients with delusions. Methods: 130 patients with delusions in the context of a nonaffective psychosis diagnosis (predominately schizophrenia) were assessed for contemporaneous levels of persecutory ideation on 5 visual analog scales. Measures were taken of anxiety, depression, threat anticipation, interpretation of ambiguity, self-focus, and negative ideas about the self. Results: Of the patients, 85% report paranoid thinking at testing. Symptoms of anxiety and depression were highly prevalent. Current paranoid thinking was associated with anxiety, depression, greater anticipation of threat events, negative interpretations of ambiguous events, a self-focused cognitive style, and negative ideas about the self. Conclusions: The study provides a clear demonstration that a range of emotion-related cognitive biases, each of which could plausibly maintain delusions, are associated with current paranoid thinking in patients with psychosis. We identified biases both in the contents of cognition and in the processing of information. Links between affect and psychosis are central to the understanding of schizophrenia. We conclude that treatment of emotional dysfunction should lead to reductions in current psychotic experiences. PMID:23223342

Hot-Electron-Induced Device Degradation during Gate-Induced Drain Leakage Stress

NASA Astrophysics Data System (ADS)

Kim, Kwang-Soo; Han, Chang-Hoon; Lee, Jun-Ki; Kim, Dong-Soo; Kim, Hyong-Joon; Shin, Joong-Shik; Lee, Hea-Beoum; Choi, Byoung-Deog

2012-11-01

We studied the interface state generation and electron trapping by hot electrons under gate-induced drain leakage (GIDL) stress in p-type metal oxide semiconductor field-effect transistors (P-MOSFETs), which are used as the high-voltage core circuit of flash memory devices. When negative voltage was applied to a drain in the off-state, a GIDL current was generated, but when high voltage was applied to the drain, electrons had a high energy. The hot electrons produced the interface state and electron trapping. As a result, the threshold voltage shifted and the off-state leakage current (trap-assisted drain junction leakage current) increased. On the other hand, electron trapping mitigated the energy band bending near the drain and thus suppressed the GIDL current generation.

High current DC negative ion source for cyclotron

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

Etoh, H., E-mail: Hrh-Etoh@shi.co.jp; Aoki, Y.; Mitsubori, H.

2016-02-15

A filament driven multi-cusp negative ion source has been developed for proton cyclotrons in medical applications. In Cs-free operation, continuous H{sup −} beam of 10 mA and D{sup −} beam of 3.3 mA were obtained stably at an arc-discharge power of 3 kW and 2.4 kW, respectively. In Cs-seeded operation, H{sup −} beam current reached 22 mA at a lower arc power of 2.6 kW with less co-extracted electron current. The optimum gas flow rate, which gives the highest H{sup −} current, was 15 sccm in the Cs-free operation, while it decreased to 4 sccm in the Cs-seeded operation. Themore » relationship between H{sup −} production and the design/operating parameters has been also investigated by a numerical study with KEIO-MARC code, which gives a reasonable explanation to the experimental results of the H{sup −} current dependence on the arc power.« less

Corrugator activity confirms immediate negative affect in surprise

PubMed Central

Topolinski, Sascha; Strack, Fritz

2015-01-01

The emotion of surprise entails a complex of immediate responses, such as cognitive interruption, attention allocation to, and more systematic processing of the surprising stimulus. All these processes serve the ultimate function to increase processing depth and thus cognitively master the surprising stimulus. The present account introduces phasic negative affect as the underlying mechanism responsible for this switch in operating mode. Surprising stimuli are schema-discrepant and thus entail cognitive disfluency, which elicits immediate negative affect. This affect in turn works like a phasic cognitive tuning switching the current processing mode from more automatic and heuristic to more systematic and reflective processing. Directly testing the initial elicitation of negative affect by surprising events, the present experiment presented high and low surprising neutral trivia statements to N = 28 participants while assessing their spontaneous facial expressions via facial electromyography. High compared to low surprising trivia elicited higher corrugator activity, indicative of negative affect and mental effort, while leaving zygomaticus (positive affect) and frontalis (cultural surprise expression) activity unaffected. Future research shall investigate the mediating role of negative affect in eliciting surprise-related outcomes. PMID:25762956

Corrugator activity confirms immediate negative affect in surprise.

PubMed

Topolinski, Sascha; Strack, Fritz

2015-01-01

The emotion of surprise entails a complex of immediate responses, such as cognitive interruption, attention allocation to, and more systematic processing of the surprising stimulus. All these processes serve the ultimate function to increase processing depth and thus cognitively master the surprising stimulus. The present account introduces phasic negative affect as the underlying mechanism responsible for this switch in operating mode. Surprising stimuli are schema-discrepant and thus entail cognitive disfluency, which elicits immediate negative affect. This affect in turn works like a phasic cognitive tuning switching the current processing mode from more automatic and heuristic to more systematic and reflective processing. Directly testing the initial elicitation of negative affect by surprising events, the present experiment presented high and low surprising neutral trivia statements to N = 28 participants while assessing their spontaneous facial expressions via facial electromyography. High compared to low surprising trivia elicited higher corrugator activity, indicative of negative affect and mental effort, while leaving zygomaticus (positive affect) and frontalis (cultural surprise expression) activity unaffected. Future research shall investigate the mediating role of negative affect in eliciting surprise-related outcomes.

Negative DC corona discharge current characteristics in a flowing two-phase (air + suspended smoke particles) fluid

NASA Astrophysics Data System (ADS)

Berendt, Artur; Domaszka, Magdalena; Mizeraczyk, Jerzy

2017-04-01

The electrical characteristics of a steady-state negative DC corona discharge in a two-phase fluid (air with suspended cigarette smoke particles) flowing along a chamber with a needle-to-plate electrode arrangement were experimentally investigated. The two-phase flow was transverse in respect to the needle-to-plate axis. The velocity of the transverse two-phase flow was limited to 0.8 m/s, typical of the electrostatic precipitators. We found that three discharge current modes of the negative corona exist in the two-phase (air + smoke particles) fluid: the Trichel pulses mode, the "Trichel pulses superimposed on DC component" mode and the DC component mode, similarly as in the corona discharge in air (a single-phase fluid). The shape of Trichel pulses in the air + suspended particles fluid is similar to that in air. However, the Trichel pulse amplitudes are higher than those in "pure" air while their repetition frequency is lower. As a net consequence of that the averaged corona discharge current in the two-phase fluid is lower than in "pure" air. It was also found that the average discharge current decreases with increasing suspended particle concentration. The calculations showed that the dependence of the average negative corona current (which is a macroscopic corona discharge parameter) on the particle concentration can be explained by the particle-concentration dependencies of the electric charge of Trichel pulse and the repetition frequency of Trichel pulses, both giving a microscopic insight into the electrical phenomena in the negative corona discharge. Our investigations showed also that the average corona discharge current in the two-phase fluid is almost unaffected by the transverse fluid flow up to a velocity of 0.8 m/s. Contribution to the topical issue "The 15th International Symposium on High Pressure Low Temperature Plasma Chemistry (HAKONE XV)", edited by Nicolas Gherardi and Tomáš Hoder

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

Choi, Hyun-Sik; Jeon, Sanghun, E-mail: jeonsh@korea.ac.kr

Upon light exposure, an indium-zinc-oxide (IZO) thin-film transistor (TFT) presents higher photoconductivity by several orders of magnitude at the negative gate bias region. Among various device geometrical factors, scaling down the channel length of the photo-transistor results in an anomalous increase in photoconductivity. To probe the origin of this high photoconductivity in short-channel device, we measured transient current, current–voltage, and capacitance–voltage characteristics of IZO–TFTs with various channel lengths and widths before and after illumination. Under the illumination, the equilibrium potential region which lies far from front interface exists only in short-channel devices, forming the un-depleted conducting back channel. This regionmore » plays an important role in carrier transport under the illumination, leading to high photoconductivity in short-channel devices. Photon exposure coupled with gate-modulated band bending for short-channel devices leads to the accumulation of V{sub o}{sup ++} at the front channel and screening negative gate bias, thereby generating high current flow in the un-depleted back-channel region.« less

Exploring divergent trajectories: Disorder-specific moderators of the association between negative urgency and dysregulated eating.

PubMed

Racine, Sarah E; Martin, Shelby J

2016-08-01

Negative urgency (i.e., the tendency to act impulsively when experiencing negative emotions) is a well-established risk factor for dysregulated eating (e.g., binge eating, loss of control eating, emotional eating). However, negative urgency is transdiagnostic, in that it is associated with multiple forms of psychopathology. It is currently unclear why some individuals with high negative urgency develop dysregulated eating while others experience depressive symptoms or problematic alcohol use. Investigating disorder-specific moderators of the association between negative urgency and psychopathology may help elucidate these divergent trajectories. The current study examined interactions among negative urgency and eating disorder-specific risk factors specified in the well-established dual-pathway model of bulimic pathology (i.e., appearance pressures, thin-ideal internalization, body dissatisfaction, dietary restraint). We hypothesized that these interactions would predict dysregulated eating, but not depressive symptoms or problematic alcohol use. Latent moderated structural equation modeling was used to test this hypothesis in a large (N = 313) sample of female college students. Negative urgency was significantly associated with dysregulated eating, depressive symptoms, and problematic alcohol use. However, interactions among negative urgency and dual-pathway model variables were specific to dysregulated eating and accounted for an additional 3-5% of the variance beyond main effects. Findings suggest that eating disorder-specific risk factors may shape negative urgency into manifesting as dysregulated eating versus another form of psychopathology. Future research should use longitudinal designs to further test the impact of interactions among disorder-specific risk factors and negative urgency on divergent psychopathology trajectories. Copyright © 2016 Elsevier Ltd. All rights reserved.

Development of multi-ampered D{sup {minus}} source for fusion applications

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

Jacquot, C.; Belchenko, Y.; Bucalossi, J.

1996-07-01

Large current and high current density deuterium negative ion sources are investigated on the MANTIS test bed with the objective of producing several amperes of D{sup {minus}} beams, at an accelerated current density in the range 10{endash}20 mA/cm{sup 2}, for possible application in future neutral beam injectors, e.g. ITER. As a first step, the DRAGON source, which was built by Culham Laboratory was tested on the MANTIS test bed in order to test this large source using only {open_quote}{open_quote}pure volume{close_quote}{close_quote} production of negative ions. The accelerated negative ion current is found to be a strong function of the source operatingmore » pressure and the arc power, and a significant isotopic effect is observed. The maximum accelerated currents are 1.3 A of H{sup {minus}} (3.3 mA/cm{sup 2}) and 0.5 A (1.3 mA/cm{sup 2}) at 110 kW of arc power. Cesium injection from a non conventional dispenser together with an improved extraction system, have significantly improved the D-current. A maximum of 14 mA/cm{sup 2} of D{sup {minus}1} are accelerated at 30 kV, which corresponds potentially, to more than 5 A for a full aperture extraction with an arc power of 140 kW (2250 A of arc current). {copyright} {ital 1996 American Institute of Physics.}« less

Want More? Learn Less: Motivation Affects Adolescents Learning from Negative Feedback.

PubMed

Zhuang, Yun; Feng, Wenfeng; Liao, Yu

2017-01-01

The primary goal of the present study was to investigate how positive and negative feedback may differently facilitate learning throughout development. In addition, the role of motivation as a modulating factor was examined. Participants (children, adolescents, and adults) completed two forms of the guess and application task (GAT). Feedback from the Cool-GAT task has low motivational salience because there are no consequences, while feedback from the Hot-GAT task has high motivational salience as it pertains to receiving a reward. The results indicated that negative feedback leads to a reduction in learning compared to positive feedback. The effect of negative feedback was greater in adolescent participants compared to children and adults in the Hot-GAT task, suggesting an interaction between age and motivation level on learning. Further analysis indicated that greater risk was associated with a greater reduction in learning from negative feedback and again, the reduction was greatest in adolescents. In summary, the current study supports the idea that learning from positive feedback and negative feedback differs throughout development. In a rule-based learning task, when associative learning is primarily in practice, participants learned less from negative feedback. This reduction is amplified during adolescence when task-elicited motivation is high.

Want More? Learn Less: Motivation Affects Adolescents Learning from Negative Feedback

PubMed Central

Zhuang, Yun; Feng, Wenfeng; Liao, Yu

2017-01-01

The primary goal of the present study was to investigate how positive and negative feedback may differently facilitate learning throughout development. In addition, the role of motivation as a modulating factor was examined. Participants (children, adolescents, and adults) completed two forms of the guess and application task (GAT). Feedback from the Cool-GAT task has low motivational salience because there are no consequences, while feedback from the Hot-GAT task has high motivational salience as it pertains to receiving a reward. The results indicated that negative feedback leads to a reduction in learning compared to positive feedback. The effect of negative feedback was greater in adolescent participants compared to children and adults in the Hot-GAT task, suggesting an interaction between age and motivation level on learning. Further analysis indicated that greater risk was associated with a greater reduction in learning from negative feedback and again, the reduction was greatest in adolescents. In summary, the current study supports the idea that learning from positive feedback and negative feedback differs throughout development. In a rule-based learning task, when associative learning is primarily in practice, participants learned less from negative feedback. This reduction is amplified during adolescence when task-elicited motivation is high. PMID:28191003

Remembering others: using life scripts to access positive but not negative information.

PubMed

White, Hedy; Coppola, Harmony A; Multunas, Nichole K

2008-01-01

The current research extended to memories of others the life script theory of abstract, idealized mental representations of transitional experiences. Recent and earlier high school graduates rated positive and negative characteristics of popular, average, and unpopular girls from their schools. "Average" girls were rated as higher than average on possessing positive characteristics. Recent but not earlier graduates distinguished between popularity conditions on negative characteristics (negative information is not included in life scripts). For positive characteristics, earlier graduates remembered unpopular girls less favorably (perhaps using stereotypical scripts) than recent graduates remembered them (having greater access to episodic memories of individual girls). A smaller graduation time difference in the same direction resulted for average and popular girls.

Understanding Positive and Negative Communication Instances between Special Educators and Parents of High School Students with EBD

ERIC Educational Resources Information Center

Mires, Carolyn B.

2015-01-01

Using a multiple case study methodology, interviews were conducted to examine current practices and perceptions of the communication practices of teachers working with high school students with emotional and behavioral disorders (EBD). These interviews involved questions about general communication instances which occurred each week, communication…

High Stakes Testing in Lower-Performing High Schools: Mathematics Teachers' Perceptions of Burnout and Retention

ERIC Educational Resources Information Center

Kirtley, Karmen

2012-01-01

This dissertation grows from a concern that the current public school accountability model, designed ostensibly to increase achievement in lower-performing schools, may be creating unidentified negative consequences for teachers and students within those schools. This hermeneutical phenomenological study features the perceptions of seventeen…

Evaluating High School Students' Anxiety and Self-Efficacy towards Biology

ERIC Educational Resources Information Center

Çimen, Osman; Yilmaz, Mehmet

2015-01-01

Anxiety and self-efficacy are among the factors that impact students' performance in biology. The current study aims to investigate high school students' perception of biology anxiety and self-efficacy, in relation to gender, grade level, interest in biology, negative experience associated with biology classes, and teachers' approaches in the…

Working While Learning: Predictors of Working Learning Status in High School. ACT Research Report Series 2017-5

ERIC Educational Resources Information Center

LeFebvre, Mary

2017-01-01

Employment status in high school has been shown to have a negative relationship with measures of academic achievement which some researchers have attributed to student characteristics such as demographics and socioeconomic status. The current study investigated differences in the demographic and socioeconomic characteristics of "working…

Review of Negative Hydrogen Ion Sources

DTIC Science & Technology

1990-09-01

Kwan, A. L. Peratt, J. Kinross-Wright, F. W. Van Haaften , R. F. Hoeberling, R. Faehl, B. Carlsten, W. W. Destler*, and L. B. Warner Los Alamos...relativistic electron beams," J. Appl. Phys. 64 (2), 1 Oct. 1988, p. 3353. 4. F. W. Van Haaften , et al, "A high-voltage, high- current electron beam modulator

Extrapolation of the DIII-D high poloidal beta scenario to ITER steady-state using transport modeling

NASA Astrophysics Data System (ADS)

McClenaghan, J.; Garofalo, A. M.; Meneghini, O.; Smith, S. P.

2016-10-01

Transport modeling of a proposed ITER steady-state scenario based on DIII-D high βP discharges finds that the core confinement may be improved with either sufficient rotation or a negative central shear q-profile. The high poloidal beta scenario is characterized by a large bootstrap current fraction( 80%) which reduces the demands on the external current drive, and a large radius internal transport barrier which is associated with improved normalized confinement. Typical temperature and density profiles from the non-inductive high poloidal beta scenario on DIII-D are scaled according to 0D modeling predictions of the requirements for achieving Q=5 steady state performance in ITER with ``day one'' H&CD capabilities. Then, TGLF turbulence modeling is carried out under systematic variations of the toroidal rotation and the core q-profile. Either strong negative central magnetic shear or rotation are found to successfully provide the turbulence suppression required to maintain the temperature and density profiles. This work supported by the US Department of Energy under DE-FC02-04ER54698.

Triple-negative breast cancer--current status and future directions.

PubMed

Gluz, O; Liedtke, C; Gottschalk, N; Pusztai, L; Nitz, U; Harbeck, N

2009-12-01

Triple-negative breast cancer (TNBC) is defined by a lack of expression of both estrogen and progesterone receptor as well as human epidermal growth factor receptor 2. It is characterized by distinct molecular, histological and clinical features including a particularly unfavorable prognosis despite increased sensitivity to standard cytotoxic chemotherapy regimens. TNBC is highly though not completely concordant with various definitions of basal-like breast cancer (BLBC) defined by high-throughput gene expression analyses. The lack in complete concordance may in part be explained by both BLBC and TNBC comprising entities that in themselves are heterogeneous. Numerous efforts are currently being undertaken to improve prognosis for patients with TNBC. They comprise both optimization of choice and scheduling of common cytotoxic agents (i.e. addition of platinum salts or dose intensification strategies) and introduction of novel agents (i.e. poly-ADP-ribose-polymerase-1 inhibitors, agents targeting the epidermal growth factor receptor, multityrosine kinase inhibitors or antiangiogenic agents).

Analysis of Current DNA Encoded Library Screening Data Indicates Higher False Negative Rates for Numerically Larger Libraries.

PubMed

Satz, Alexander L; Hochstrasser, Remo; Petersen, Ann C

2017-04-10

To optimize future DNA-encoded library design, we have attempted to quantify the library size at which the signal becomes undetectable. To accomplish this we (i) have calculated that percent yields of individual library members following a screen range from 0.002 to 1%, (ii) extrapolated that ∼1 million copies per library member are required at the outset of a screen, and (iii) from this extrapolation predict that false negative rates will begin to outweigh the benefit of increased diversity at library sizes >10 8 . The above analysis is based upon a large internal data set comprising multiple screens, targets, and libraries; we also augmented our internal data with all currently available literature data. In theory, high false negative rates may be overcome by employing larger amounts of library; however, we argue that using more than currently reported amounts of library (≫10 nmoles) is impractical. The above conclusions may be generally applicable to other DNA encoded library platforms, particularly those platforms that do not allow for library amplification.

Interpretation bias and social anxiety: does interpretation bias mediate the relationship between trait social anxiety and state anxiety responses?

PubMed

Chen, Junwen; Milne, Kirby; Dayman, Janet; Kemps, Eva

2018-05-23

Two studies aimed to examine whether high socially anxious individuals are more likely to negatively interpret ambiguous social scenarios and facial expressions compared to low socially anxious individuals. We also examined whether interpretation bias serves as a mediator of the relationship between trait social anxiety and state anxiety responses, in particular current state anxiety, bodily sensations, and perceived probability and cost of negative evaluation pertaining to a speech task. Study 1 used ambiguous social scenarios and Study 2 used ambiguous facial expressions as stimuli to objectively assess interpretation bias. Undergraduate students with high and low social anxiety completed measures of state anxiety responses at three time points: baseline, after the interpretation bias task, and after the preparation for an impromptu speech. Results showed that high socially anxious individuals were more likely to endorse threat interpretations for ambiguous social scenarios and to interpret ambiguous faces as negative than low socially anxious individuals. Furthermore, negative interpretations mediated the relationship between trait social anxiety and perceived probability of negative evaluation pertaining to the speech task in Study 1 but not Study 2. The present studies provide new insight into the role of interpretation bias in social anxiety.

Steep-slope hysteresis-free negative capacitance MoS2 transistors

NASA Astrophysics Data System (ADS)

Si, Mengwei; Su, Chun-Jung; Jiang, Chunsheng; Conrad, Nathan J.; Zhou, Hong; Maize, Kerry D.; Qiu, Gang; Wu, Chien-Ting; Shakouri, Ali; Alam, Muhammad A.; Ye, Peide D.

2018-01-01

The so-called Boltzmann tyranny defines the fundamental thermionic limit of the subthreshold slope of a metal-oxide-semiconductor field-effect transistor (MOSFET) at 60 mV dec-1 at room temperature and therefore precludes lowering of the supply voltage and overall power consumption1,2. Adding a ferroelectric negative capacitor to the gate stack of a MOSFET may offer a promising solution to bypassing this fundamental barrier3. Meanwhile, two-dimensional semiconductors such as atomically thin transition-metal dichalcogenides, due to their low dielectric constant and ease of integration into a junctionless transistor topology, offer enhanced electrostatic control of the channel4-12. Here, we combine these two advantages and demonstrate a molybdenum disulfide (MoS2) two-dimensional steep-slope transistor with a ferroelectric hafnium zirconium oxide layer in the gate dielectric stack. This device exhibits excellent performance in both on and off states, with a maximum drain current of 510 μA μm-1 and a sub-thermionic subthreshold slope, and is essentially hysteresis-free. Negative differential resistance was observed at room temperature in the MoS2 negative-capacitance FETs as the result of negative capacitance due to the negative drain-induced barrier lowering. A high on-current-induced self-heating effect was also observed and studied.

Arousal (but not valence) amplifies the impact of salience.

PubMed

Sutherland, Matthew R; Mather, Mara

2018-05-01

Previous findings indicate that negative arousal enhances bottom-up attention biases favouring perceptual salient stimuli over less salient stimuli. The current study tests whether those effects were driven by emotional arousal or by negative valence by comparing how well participants could identify visually presented letters after hearing either a negative arousing, positive arousing or neutral sound. On each trial, some letters were presented in a high contrast font and some in a low contrast font, creating a set of targets that differed in perceptual salience. Sounds rated as more emotionally arousing led to more identification of highly salient letters but not of less salient letters, whereas sounds' valence ratings did not impact salience biases. Thus, arousal, rather than valence, is a key factor enhancing visual processing of perceptually salient targets.

Resonant-tunneling oscillators and multipliers for submillimeter receivers

NASA Technical Reports Server (NTRS)

Sollner, T. C. L. Gerhard

1988-01-01

Resonant tunneling through double-barrier heterostructures has attracted increasing interest recently, largely because of the fast charge transport it provides. In addition, the negative differential resistance regions that exist in the current-voltage (I-V) curve (peak-to-valley ratios of 3.5:1 at room temperature, and nearly 10:1 at 77 K, were measured) suggest that high-speed devices based on the character of the I-V curve should be possible. For example, the negative differential resistance region is capable of providing the gain necessary for high-frequency oscillations. In the laboratory attempts were made to increase the frequency and power of these oscillators and to demonstrate several different high-frequency devices.

Nonlinear effect of climate on plague during the third pandemic in China

PubMed Central

Xu, Lei; Liu, Qiyong; Stige, Leif Chr.; Ben Ari, Tamara; Fang, Xiye; Chan, Kung-Sik; Wang, Shuchun; Stenseth, Nils Chr.; Zhang, Zhibin

2011-01-01

Over the years, plague has caused a large number of deaths worldwide and subsequently changed history, not the least during the period of the Black Death. Of the three plague pandemics, the third is believed to have originated in China. Using the spatial and temporal human plague records in China from 1850 to 1964, we investigated the association of human plague intensity (plague cases per year) with proxy data on climate condition (specifically an index for dryness/wetness). Our modeling analysis demonstrates that the responses of plague intensity to dry/wet conditions were different in northern and southern China. In northern China, plague intensity generally increased when wetness increased, for both the current and the previous year, except for low intensity during extremely wet conditions in the current year (reflecting a dome-shaped response to current-year dryness/wetness). In southern China, plague intensity generally decreased when wetness increased, except for high intensity during extremely wet conditions of the current year. These opposite effects are likely related to the different climates and rodent communities in the two parts of China: In northern China (arid climate), rodents are expected to respond positively to high precipitation, whereas in southern China (humid climate), high precipitation is likely to have a negative effect. Our results suggest that associations between human plague intensity and precipitation are nonlinear: positive in dry conditions, but negative in wet conditions. PMID:21646523

Nonlinear effect of climate on plague during the third pandemic in China.

PubMed

Xu, Lei; Liu, Qiyong; Stige, Leif Chr; Ben Ari, Tamara; Fang, Xiye; Chan, Kung-Sik; Wang, Shuchun; Stenseth, Nils Chr; Zhang, Zhibin

2011-06-21

Over the years, plague has caused a large number of deaths worldwide and subsequently changed history, not the least during the period of the Black Death. Of the three plague pandemics, the third is believed to have originated in China. Using the spatial and temporal human plague records in China from 1850 to 1964, we investigated the association of human plague intensity (plague cases per year) with proxy data on climate condition (specifically an index for dryness/wetness). Our modeling analysis demonstrates that the responses of plague intensity to dry/wet conditions were different in northern and southern China. In northern China, plague intensity generally increased when wetness increased, for both the current and the previous year, except for low intensity during extremely wet conditions in the current year (reflecting a dome-shaped response to current-year dryness/wetness). In southern China, plague intensity generally decreased when wetness increased, except for high intensity during extremely wet conditions of the current year. These opposite effects are likely related to the different climates and rodent communities in the two parts of China: In northern China (arid climate), rodents are expected to respond positively to high precipitation, whereas in southern China (humid climate), high precipitation is likely to have a negative effect. Our results suggest that associations between human plague intensity and precipitation are nonlinear: positive in dry conditions, but negative in wet conditions.

Does being attractive always help? Positive and negative effects of attractiveness on social decision making.

PubMed

Agthe, Maria; Spörrle, Matthias; Maner, Jon K

2011-08-01

Previous studies of organizational decision making demonstrate an abundance of positive biases directed toward highly attractive individuals. The current research, in contrast, suggests that when the person being evaluated is of the same sex as the evaluator, attractiveness hurts, rather than helps. Three experiments assessing evaluations of potential job candidates (Studies 1 and 3) and university applicants (Study 2) demonstrated positive biases toward highly attractive other-sex targets but negative biases toward highly attractive same-sex targets. This pattern was mediated by variability in participants' desire to interact with versus avoid the target individual (Studies 1 and 2) and was moderated by participants' level of self-esteem (Study 3); the derogation of attractive same-sex targets was not observed among people with high self-esteem. Findings demonstrate an important exception to the positive effects of attractiveness in organizational settings and suggest that negative responses to attractive same-sex targets stem from perceptions of self-threat.

Metacognition in first-episode psychosis and its association with positive and negative symptom profiles.

PubMed

Trauelsen, Anne Marie; Gumley, Andrew; Jansen, Jens Einar; Pedersen, Marlene Buch; Nielsen, Hanne-Grethe Lyse; Trier, Christopher Høier; Haahr, Ulrik H; Simonsen, Erik

2016-04-30

There is growing evidence that metacognitive abilities which include the ability to synthesize knowledge regarding mental states in self and others and use this ability to solve problems are impaired in non-affective psychosis and associated with positive and negative symptom severity. We sought to (a) investigate the severity of metacognitive impairments in first-episode psychosis (FEP) compared to non-clinical controls and (b) explore associations with positive and negative symptom profiles. Ninety-seven people with FEP were compared to 101 control persons. Metacognition was assessed with interviews and the Metacognitive assessment scale-abbreviated. Four groups based on positive and negative symptoms were identified by cluster analysis and compared on metacognition, childhood adversities, duration of untreated psychosis and premorbid social and academic adjustment. Those with high levels of negative symptoms had poorer metacognitive abilities. Those with high positive and low negative symptoms did not have poorer metacognitive abilities than those with low positive and negative symptoms. None of the other predictors differed between the groups. The FEP group had poorer metacognitive abilities than the control group. Inclusion of metacognition in psychosis models may improve our understanding of negative symptoms, while previous findings of a relation with positive symptoms may have been confounded. Implications for current interventions are discussed. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

The Long Non-Coding RNA MIR503HG Enhances Proliferation of Human ALK-Negative Anaplastic Large-Cell Lymphoma.

PubMed

Huang, Po-Shuan; Chung, I-Hsiao; Lin, Yang-Hsiang; Lin, Tzu-Kang; Chen, Wei-Jan; Lin, Kwang-Huei

2018-05-14

Anaplastic lymphoma kinase (ALK)-negative anaplastic large-cell lymphoma (ALCL) is a rare type of highly malignant, non-Hodgkin lymphoma. Currently, only a few gene rearrangements have been linked to ALK-negative ALCL progression. However, the specific molecular mechanisms underlying the growth of ALK-negative ALCL tumors remain unclear. Here, we investigated aberrantly expressed, long non-coding RNAs (lncRNAs) in ALK-negative ALCL and assessed their potential biological function. MIR503HG ( miR-503 host gene) was highly expressed in ALK-negative cell lines and was significantly upregulated in tumors in mice formed from ALK-negative ALCL cell lines. Depletion of MIR503HG suppressed tumor cell proliferation in vivo and in vitro; conversely, its overexpression enhanced tumor cell growth. MIR503HG -induced proliferation was mediated by the induction of microRNA-503 ( miR - 503 ) and suppression of Smurf2, resulting in stabilization of the tumor growth factor-β receptor (TGFBR) and enhanced tumor cell growth. Collectively, these findings support a potential role for MIR503HG in cancer cell proliferation through the miR-503 /Smurf2/TGFBR axis and indicate that MIR503HG is a potential marker in ALK-negative ALCL.

The Economic Impact of Closed-Incision Negative-Pressure Therapy in High-Risk Abdominal Incisions: A Cost-Utility Analysis.

PubMed

Chopra, Karan; Gowda, Arvind U; Morrow, Chris; Holton, Luther; Singh, Devinder P

2016-04-01

Complex abdominal wall reconstruction is beset by postoperative complications. A recent meta-analysis comparing the use of closed-incision negative-pressure therapy to standard dressings found a statistically significant reduction in surgical-site infection. The use of closed-incision negative-pressure therapy is gaining acceptance in this population; however, the economic impact of this innovative dressing remains unknown. In this study, a cost-utility analysis was performed assessing closed-incision negative-pressure therapy and standard dressings following closure of abdominal incisions in high-risk patients. Cost-utility methodology involved reviewing literature related to closed-incision negative-pressure therapy in abdominal wall surgery, obtaining utility estimates to calculate quality-adjusted life-year scores for successful surgery and surgery complicated by surgical-site infection, summing costs using Medicare Current Procedural Terminology codes, and creating a decision tree illuminating the most cost-effective dressing strategy. One-way sensitivity analysis was performed to assess the robustness of the results. The aforementioned meta-analysis comparing closed-incision negative-pressure therapy to standard dressings included a subset of five studies assessing abdominal wall surgery in 829 patients (260 closed-incision negative-pressure therapy and 569 standard dressings). Decision tree analysis revealed an estimated savings of $1546.52 and a gain of 0.0024 quality-adjusted life-year with closed-incision negative-pressure therapy compared with standard dressings; therefore, closed-incision negative-pressure therapy is a dominant treatment strategy. One-way sensitivity analysis revealed that closed-incision negative-pressure therapy is a cost-effective option when the surgical-site infection rate is greater than 16.39 percent. The use of closed-incision negative-pressure therapy is cost-saving following closure of abdominal incisions in high-risk patients.

Parental Divorce during Adolescence and Adjustment in Early Adulthood.

ERIC Educational Resources Information Center

Richardson, Stacey; McCabe, Marita P.

2001-01-01

Examined the impact of parental divorce during adolescence, interparental conflict, and intimacy with parents on young adult adjustment. High levels of interparental conflict were found to be negatively associated with adjustment and current intimacy of parents. (Author)

Long pulse acceleration of MeV class high power density negative H{sup −} ion beam for ITER

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

Umeda, N., E-mail: umeda.naotaka@jaea.go.jp; Kojima, A.; Kashiwagi, M.

2015-04-08

R and D of high power density negative ion beam acceleration has been carried out at MeV test facility in JAEA to realize ITER neutral beam accelerator. The main target is H{sup −} ion beam acceleration up to 1 MeV with 200 A/m{sup 2} for 60 s whose pulse length is the present facility limit. For long pulse acceleration at high power density, new extraction grid (EXG) has been developed with high cooling capability, which electron suppression magnet is placed under cooling channel similar to ITER. In addition, aperture size of electron suppression grid (ESG) is enlarged from 14 mmmore » to 16 mm to reduce direct interception on the ESG and emission of secondary electron which leads to high heat load on the upstream acceleration grid. By enlarging ESG aperture, beam current increased 10 % at high current beam and total acceleration grid heat load reduced from 13 % to 10 % of input power at long pulse beam. In addition, heat load by back stream positive ion into the EXG is measured for the first time and is estimated as 0.3 % of beam power, while heat load by back stream ion into the source chamber is estimated as 3.5 ~ 4.0 % of beam power. Beam acceleration up to 60 s which is the facility limit, has achieved at 683 keV, 100 A/m{sup 2} of negative ion beam, whose energy density increases two orders of magnitude since 2011.« less

A 60 mA DC H- multi cusp ion source developed at TRIUMF

NASA Astrophysics Data System (ADS)

Jayamanna, K.; Ames, F.; Bylinskii, I.; Lovera, M.; Minato, B.

2018-07-01

This paper describes the latest high-current multi cusp type ion source developed at TRIUMF, which is capable of producing a negative hydrogen ion beam (H-) of 60 mA of direct current at 140V and 90A arc. The results achieved to date including emittance measurements and filament lifetime issues are presented. The low current version of this ion source is suitable for medical cyclotrons as well as accelerators and the high current version is intended for producing large neutral hydrogen beams for fusion research. The description of the source magnetic configuration, the electron filter profile and the differential pumping techniques given in the paper will allow the building of an arc discharge H- ion source with similar properties.

High false-negative rate of anti-HCV among Egyptian patients on regular hemodialysis.

PubMed

El-Sherif, Assem; Elbahrawy, Ashraf; Aboelfotoh, Atef; Abdelkarim, Magdy; Saied Mohammad, Abdel-Gawad; Abdallah, Abdallah Mahmoud; Mostafa, Sadek; Elmestikawy, Amr; Elwassief, Ahmed; Salah, Mohamed; Abdelbaseer, Mohamed Ali; Abdelwahab, Kouka Saadeldin

2012-07-01

Routine serological testing for hepatitis C virus (HCV) infection among hemodialysis (HD) patients is currently recommended. A dilemma existed on the value of serology because some investigators reported a high rate of false-negative serologic testing. In this study, we aimed to detect the false-negative rate of anti-HCV among Egyptian HD patients. Seventy-eight HD patients, negative for anti-HCV, anti-HIV, and hepatitis B surface antigen, were tested for HCV RNA by reverse transcriptase polymerase chain reaction (RT-PCR). In the next step, the viral load was quantified by real-time PCR in RT-PCR-positive patients. Risk factors for HCV infection, as well as clinical and biochemical indicators of liver disease, were compared between false-negative and true-negative anti-HCV HD patients. The frequency of false-negative anti-HCV was 17.9%. Frequency of blood transfusion, duration of HD, dialysis at multiple centers, and diabetes mellitus were not identified as risk factors for HCV infection. The frequency of false-negative results had a linear relation to the prevalence of HCV infection in the HD units. Timely identification of HCV within dialysis units is needed in order to lower the risk of HCV spread within the HD units. The high false-negative rate of anti-HCV among HD patients in our study justifies testing of a large scale of patients for precious assessment of effectiveness of nucleic acid amplification technology testing in screening HD patient. © 2012 The Authors. Hemodialysis International © 2012 International Society for Hemodialysis.

Properties of micro-arc oxidation coatings on aluminum alloy at different negative peak current densities

NASA Astrophysics Data System (ADS)

Gu, Xin; Jiang, Bailing; Li, Hongtao; Liu, Cancan; Shao, Lianlian

2018-05-01

Micro-arc oxidation coatings were fabricated on 6061 aluminum alloy using whereby bipolar pulse mode in the case of different negative peak current densities. The phase composition, microstructures and wear properties were studied using x-ray diffraction, scanning electron microscopy and ball-on-disk wear tester, respectively. As results indicate, by virtue of negative peak current density, the oxygen can be expelled by produced hydrogen on anode in the case of negative pulse width and via the opened discharge channel. The results of x-ray diffraction, surface and cross-sectional morphology indicated that the coating was structured compactly taking on less small-diameter micro-pores and defects with negative peak current density of 75 A dm‑2. Additionally, as the results of wear tracks and weight loss bespeak, by virtue of appropriate negative peak current density, coatings resisted the abrasive wear and showed excellent wear resistance.

Examining weight concern and delay discounting in adolescent females.

PubMed

Thamotharan, Sneha; Lange, Krista; Ramos, Ashley; Fields, Sherecce

2016-04-01

Pediatric obesity is a growing public health concern that contributes to high rates of negative long-term physical and mental health outcomes. Research focused on identifying risk for pediatric obesity has linked delay discounting, or an inclination for immediate rewards, as well as weight concern to individuals with greater Body Mass Index (BMI). The current study seeks to fill a void in the literature by examining how these two variables interact to promote higher BMI in female adolescents. Adolescent (n=60) females between the ages of 13-19years (mage=17.45, SD=1.74) of age completed the Eating Disorder Examination Questionnaire (EDE-Q) and the Delay Discounting Questionnaire. A mediation model examined whether delay discounting accounted for the relationship between weight concern and BMI. Results indicate that in the current study weight concern was negatively related to delay discounting and delay discounting was negatively related to BMI. The overall model revealed that a partial mediation occurred [b=1.28, t(60)=4.92, p<0.01]. These results suggest that while impulsivity is an important factor to consider, other constructs may also be influential in how weight concerns contribute to greater BMI. Nevertheless, the results indicate that prevention and interventions should identify females with high levels of both weight concern and impulsivity as an increased risk for experiencing pediatric obesity and long-term negative health outcomes. Copyright © 2016 Elsevier Ltd. All rights reserved.

Using negative emotions to trace the experience of borderline personality pathology: Interconnected relationships revealed in an experience sampling study

PubMed Central

Law, Mary Kate; Fleeson, William; Arnold, Elizabeth Mayfield; Furr, R. Michael

2015-01-01

While emotional difficulties are highly implicated in borderline personality disorder (BPD), the dynamic relationships between emotions and BPD symptoms that occur in everyday life are unknown. The current paper examined the function of negative emotions as they relate to BPD symptoms in real time. Experience sampling methodology with 281 participants measured negative emotions and borderline symptoms, expressed as a spectrum of experiences, five times daily for two weeks. Overall, having a BDP diagnosis was associated with experiencing more negative emotions. Multilevel modeling supported positive concurrent relationships between negative emotions and BPD symptoms. Lagged models showed that even after three hours negative emotions and several symptoms continued to influence each other. Therefore, results indicated that negative emotions and BPD symptoms are intricately related; some evidenced long-lasting relationships. This research supports emotion-symptom contingencies within BPD and provides insight regarding the reactivity and functionality of negative emotions in borderline pathology. PMID:25710731

Using Negative Emotions to Trace the Experience of Borderline Personality Pathology: Interconnected Relationships Revealed in an Experience Sampling Study.

PubMed

Law, Mary Kate; Fleeson, William; Arnold, Elizabeth Mayfield; Furr, R Michael

2016-02-01

While emotional difficulties are highly implicated in borderline personality disorder (BPD), the dynamic relationships between emotions and BPD symptoms that occur in everyday life are unknown. The current paper examined the function of negative emotions as they relate to BPD symptoms in real time. Experience sampling methodology with 281 participants measured negative emotions and borderline symptoms, expressed as a spectrum of experiences, five times daily for two weeks. Overall, having a BDP diagnosis was associated with experiencing more negative emotions. Multilevel modeling supported positive concurrent relationships between negative emotions and BPD symptoms. Lagged models showed that even after 3 hours negative emotions and several symptoms continued to influence each other. Therefore, results indicated that negative emotions and BPD symptoms are intricately related; some evidenced long-lasting relationships. This research supports emotion-symptom contingencies within BPD and provides insight regarding the reactivity and functionality of negative emotions in borderline pathology.

Method of preparing electrodes with porous current collector structures and solid reactants for secondary electrochemical cells

DOEpatents

Gay, Eddie C.; Martino, Fredric J.

1976-01-01

Particulate electrode reactants, for instance transition metal sulfides for the positive electrodes and lithium alloys for the negative electrodes, are vibratorily compacted into porous, electrically conductive structures. Structures of high porosity support sufficient reactant material to provide high cell capacity per unit weight while serving as an electrical current collector to improve the utilization of reactant materials. Pore sizes of the structure and particle sizes of the reactant material are selected to permit uniform vibratory loading of the substrate without settling of the reactant material during cycling.

High-voltage crowbar circuit with cascade-triggered series ignitrons

DOEpatents

Baker, William R. [Orinda, CA

1980-11-04

A series string of ignitrons for switching a large current at high voltage to ground. Switching is initiated by means of a negative trigger pulse applied to the cathode of the lowest voltage level ignitron next to ground to draw ground current through diodes in the ignitor circuit. The trigger pulse is applied thereby to the next higher ignitron cathode and sequentially to the remainder of the ignitrons in the string through diodes in respective ignitor circuits. Full line voltage is held off of nonconducting diodes and ignitrons by means of varistors.

High-voltage crowbar circuit with cascade-triggered series ignitrons

DOEpatents

Baker, W.R.

A series string of ignitrons for switching a large current at high voltage to ground is discussed. Switching is initiated by means of a negative trigger pulse applied to the cathode of the lowest voltage level ignitron next to ground to draw ground current through diodes in the ignitor circuit. The trigger pulse is applied thereby to the next higher ignitron cathode and sequentially to the remainder of the ignitrons in the string through diodes in respective ignitor circuits. Full line voltage is held off of nonconducting diodes and ignitrons by means of varistors.

High-voltage crowbar circuit with cascade-triggered series ignitrons

DOEpatents

Baker, W.R.

1980-11-04

A series string of ignitrons for switching a large current at high voltage to ground. Switching is initiated by means of a negative trigger pulse applied to the cathode of the lowest voltage level ignitron next to ground to draw ground current through diodes in the ignitor circuit. The trigger pulse is applied thereby to the next higher ignitron cathode and sequentially to the remainder of the ignitrons in the string through diodes in respective ignitor circuits. Full line voltage is held off of nonconducting diodes and ignitrons by means of varistors. 1 fig.

The Effects of Out-of-School Suspension on High School Students: An Inside View

ERIC Educational Resources Information Center

Scelso, Alicia K.

2013-01-01

This study examined the effects of out-of-school suspension on high school students. Its purpose was to determine if exclusionary discipline practices led to negative consequences such as poor academic achievement and juvenile delinquency. The study also hoped to generate new insight into current disciplinary practices in order to yield a better…

Effect of current stimulus on in vivo cochlear mechanics

NASA Astrophysics Data System (ADS)

Parthasarathi, Anand A.; Grosh, Karl; Zheng, Jiefu; Nuttall, Alfred L.

2003-01-01

In this paper, the influence of direct current stimulation on the acoustic impulse response of the basilar membrane (BM) is studied. A positive current applied in the scala vestibuli relative to a ground electrode in the scala tympani is found to enhance gain and increase the best frequency at a given location on the BM. An opposite effect is found for a negative current. Also, the amplitude of low-frequency cochlear microphonic at high sound levels is found to change with the concurrent application of direct current stimulus. BM vibrations in response to pure tone acoustic excitation are found to possess harmonics whose levels relative to the fundamental increase with the application of positive current and decrease with the application of negative current. A model for outer hair cell activity that couples changes in length and stiffness to transmembrane potential is used to interpret the results of these experiments and others in the literature. The importance of the in vivo mechanical and electrical loading is emphasized. Simulation results show the somewhat paradoxical finding that for outer hair cells under tension, hyperpolarization causes shortening of the cell length due to the dominance of voltage dependent stiffness changes.

Stability amidst turmoil: Grit buffers the effects of negative life events on suicidal ideation.

PubMed

Blalock, Dan V; Young, Kevin C; Kleiman, Evan M

2015-08-30

The goal of the current study is to examine the role of grit as a resilience factor that reduces the risk for suicidal ideation conferred by negative life events. Participants (N=209) completed measures of negative life events and grit at baseline and a measure of suicidal ideation at follow-up four weeks later. Poisson regression analyses found that higher levels of grit buffered the relationship between negative life events and suicidal ideation such that negative life events only predicted suicidal ideation if grit was low. These results suggest that high grit can abate the increased suicidal ideation associated with negative life events. Aside from absolute levels of suicidal ideation, being able to predict or buffer dramatic shifts in suicidal ideation can be a useful diagnostic tool during interventions. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Perceived social pressure not to experience negative emotion is linked to selective attention for negative information.

PubMed

Bastian, Brock; Pe, Madeline Lee; Kuppens, Peter

2017-02-01

Social norms and values may be important predictors of how people engage with and regulate their negative emotional experiences. Previous research has shown that social expectancies (the perceived social pressure not to feel negative emotion (NE)) exacerbate feelings of sadness. In the current research, we examined whether social expectancies may be linked to how people process emotional information. Using a modified classical flanker task involving emotional rather than non-emotional stimuli, we found that, for those who experienced low levels of NE, social expectancies were linked to the selective avoidance of negative emotional information. Those who experienced high levels of NE did not show a selective avoidance of negative emotional information. The findings suggest that, for people who experience many NEs, social expectancies may lead to discrepancies between how they think they ought to feel and the kind of emotional information they pay attention to.

Fitting In and Standing Out: Increasing the Use of Alcohol Protective Behavioral Strategies with a Deviance Regulation Intervention

PubMed Central

Dvorak, Robert D.; Pearson, Matthew R.; Neighbors, Clayton; Martens, Matthew P.

2015-01-01

OBJECTIVE Heavy alcohol use remains a consistent public health concern on college campuses. The current pilot study used Deviance Regulation Theory (DRT) to modify Protective Behavioral Strategies (PBS) among college student drinkers to reduce alcohol use and alcohol-related consequences. METHODS The sample was comprised of current college student drinkers (n = 76; 53.95% female) ranging in age from 18-24 (M = 19.29, SD = 1.42). Participants were randomly assigned to receive a positive or negative framed message. They then reported on use of alcohol protective behavioral strategies (via the Protective Behavioral Strategies Scale), alcohol consumption (via the Modified Daily Drinking Questionnaire), and alcohol-related consequences (via the Young Adults Alcohol Consequences Questionnaire) each week for six weeks. RESULTS AND CONCLUSIONS Among drinkers with low PBS use norms, a positively, versus a negatively, framed message resulted in increased PBS use and consequently less alcohol consumption and fewer alcohol-related consequences. Among drinkers with high PBS use norms, a negatively, versus positively, framed message resulted in increased PBS use and consequently lower alcohol consumption and fewer alcohol-related consequences. However, these effects were only relevant among those who strongly believed the DRT frame. Findings suggest assigning drinkers to frames based on perceived PBS use norms and increasing belief in the frame may be one approach to increasing responsible drinking patterns among college students. Furthermore, the current data suggests important boundary conditions for norm-based interventions. PUBLIC HEALTH RELEVANCE This study of college student drinkers who received either a positive or negative framed message about reducing their drinking found that a Deviance Regulation intervention might be effective at increasing responsible alcohol use, but only among students with a high acceptance of the intervention materials. PMID:25798727

Analysis of microscopic parameters of surface charging in polymer caused by defocused electron beam irradiation.

PubMed

Liu, Jing; Zhang, Hai-Bo

2014-12-01

The relationship between microscopic parameters and polymer charging caused by defocused electron beam irradiation is investigated using a dynamic scattering-transport model. The dynamic charging process of an irradiated polymer using a defocused 30 keV electron beam is conducted. In this study, the space charge distribution with a 30 keV non-penetrating e-beam is negative and supported by some existing experimental data. The internal potential is negative, but relatively high near the surface, and it decreases to a maximum negative value at z=6 μm and finally tend to 0 at the bottom of film. The leakage current and the surface potential behave similarly, and the secondary electron and leakage currents follow the charging equilibrium condition. The surface potential decreases with increasing beam current density, trap concentration, capture cross section, film thickness and electron-hole recombination rate, but with decreasing electron mobility and electron energy. The total charge density increases with increasing beam current density, trap concentration, capture cross section, film thickness and electron-hole recombination rate, but with decreasing electron mobility and electron energy. This study shows a comprehensive analysis of microscopic factors of surface charging characteristics in an electron-based surface microscopy and analysis. Copyright © 2014 Elsevier Ltd. All rights reserved.

Negative Feedback Mediated by Fast Inhibitory Autapse Enhances Neuronal Oscillations Near a Hopf Bifurcation Point

NASA Astrophysics Data System (ADS)

Jia, Bing

One-parameter and two-parameter bifurcations of the Morris-Lecar (ML) neuron model with and without the fast inhibitory autapse, which is a synapse from a neuron onto itself, are investigated. The ML neuron model without autapse manifests an inverse Hopf bifurcation point from firing to a depolarized resting state with high level of membrane potential, with increasing depolarization current. When a fast inhibitory autapse is introduced, a negative feedback or inhibitory current is applied to the ML model. With increasing conductance of the autapse to middle level, the depolarized resting state near the inverse Hopf bifurcation point can change to oscillation and the parameter region of the oscillation becomes wide, which can be well interpreted by the dynamic responses of the depolarized resting state to the inhibitory current stimulus mediated by the autapse. The enlargement of the parameter region of the oscillation induced by the negative feedback presents a novel viewpoint different from the traditional one that inhibitory synapse often suppresses the neuronal oscillation activities. Furthermore, complex nonlinear dynamics such as the coexisting behaviors and codimension-2 bifurcations including the Bautin and cusp bifurcations are acquired. The relationship between the bifurcations and the depolarization block, a physiological concept that indicates a neuron can enter resting state when receiving the depolarization current, is discussed.

Towards the development of improved tests for negative symptoms of schizophrenia in a validated animal model.

PubMed

Sahin, Ceren; Doostdar, Nazanin; Neill, Joanna C

2016-10-01

Negative symptoms in schizophrenia remain an unmet clinical need. There is no licensed treatment specifically for this debilitating aspect of the disorder and effect sizes of new therapies are too small to make an impact on quality of life and function. Negative symptoms are multifactorial but often considered in terms of two domains, expressive deficit incorporating blunted affect and poverty of speech and avolition incorporating asociality and lack of drive. There is a clear need for improved understanding of the neurobiology of negative symptoms which can be enabled through the use of carefully validated animal models. While there are several tests for assessing sociability in animals, tests for blunted affect in schizophrenia are currently lacking. Two paradigms have recently been developed for assessing negative affect of relevance to depression in rats. Here we assess their utility for studying negative symptoms in schizophrenia using our well validated model for schizophrenia of sub-chronic (sc) treatment with Phencyclidine (PCP) in adult female rats. Results demonstrate that sc PCP treatment produces a significant negative affect bias in response to a high value reward in the optimistic and affective bias tests. Our results are not easily explained by the known cognitive deficits induced by sc PCP and support the hypothesis of a negative affective bias in this model. We suggest that further refinement of these two tests will provide a means to investigate the neurobiological basis of negative affect in schizophrenia, thus supporting the assessment of efficacy of new targets for this currently untreated symptom domain. Copyright © 2016 Elsevier B.V. All rights reserved.

Drug-resistant gram-negative uropathogens: A review.

PubMed

Khoshnood, Saeed; Heidary, Mohsen; Mirnejad, Reza; Bahramian, Aghil; Sedighi, Mansour; Mirzaei, Habibollah

2017-10-01

Urinary tract infection(UTI) caused by Gram-negative bacteria is the second most common infectious presentation in community medical practice. Approximately 150 million people are diagnosed with UTI each year worldwide. Drug resistance in Gram-negative uropathogens is a major global concern which can lead to poor clinical outcomes including treatment failure, development of bacteremia, requirement for intravenous therapy, hospitalization, and extended length of hospital stay. The mechanisms of drug resistance in these bacteria are important due to they are often not identified by routine susceptibility tests and have an exceptional potential for outbreaks. Treatment of UTIs depends on the access to effective drugs, which is now threatened by antibiotic resistant Gram-negative uropathogens. Although several effective antibiotics with activity against highly resistant Gram-negatives are available, there is not a unique antibiotic with activity against the high variety of resistance. Therefore, antimicrobial susceptibility tests, correlation between clinicians and laboratories, development of more rapid diagnostic methods, and continuous monitoring of drug resistance are urgent priorities. In this review, we will discuss about the current global status of drug-resistant Gram-negative uropathogens and their mechanisms of drug resistance to provide new insights into their treatment options. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Negative differential resistance in low Al-composition p-GaN/Mg-doped Al0.15Ga0.85N/n+-GaN hetero-junction grown by metal-organic chemical vapor deposition on sapphire substrate

NASA Astrophysics Data System (ADS)

Zhang, Kexiong; Liang, Hongwei; Shen, Rensheng; Wang, Dongsheng; Tao, Pengcheng; Liu, Yang; Xia, Xiaochuan; Luo, Yingmin; Du, Guotong

2014-02-01

Negative differential resistance (NDR) behavior was observed in low Al-composition p-GaN/Mg-doped-Al0.15Ga0.85N/n+-GaN hetero-junction grown by metal-organic chemical vapor deposition on sapphire substrate. The energy band and free carrier concentration of hetero-junction were studied by the model of the self-consistent solution of Schrödinger-Poisson equations combined with polarization engineering theory. At the forward bias of 0.95 V, the NDR effect has a high peak-to-valley current ratio of ˜9 with a peak current of 22.4 mA (˜current density of 11.4 A/cm2). An interesting phenomenon of NDR disappearance after consecutive scans and recurrence after electrical treatment was observed, which was associated with Poole-Frenkel effect.

Coherent Interlayer Tunneling and Negative Differential Resistance with High Current Density in Double Bilayer Graphene-WSe2 Heterostructures.

PubMed

Burg, G William; Prasad, Nitin; Fallahazad, Babak; Valsaraj, Amithraj; Kim, Kyounghwan; Taniguchi, Takashi; Watanabe, Kenji; Wang, Qingxiao; Kim, Moon J; Register, Leonard F; Tutuc, Emanuel

2017-06-14

We demonstrate gate-tunable resonant tunneling and negative differential resistance between two rotationally aligned bilayer graphene sheets separated by bilayer WSe 2 . We observe large interlayer current densities of 2 and 2.5 μA/μm 2 and peak-to-valley ratios approaching 4 and 6 at room temperature and 1.5 K, respectively, values that are comparable to epitaxially grown resonant tunneling heterostructures. An excellent agreement between theoretical calculations using a Lorentzian spectral function for the two-dimensional (2D) quasiparticle states, and the experimental data indicates that the interlayer current stems primarily from energy and in-plane momentum conserving 2D-2D tunneling, with minimal contributions from inelastic or non-momentum-conserving tunneling. We demonstrate narrow tunneling resonances with intrinsic half-widths of 4 and 6 meV at 1.5 and 300 K, respectively.

[PD-L1 expression and PD-1/PD-L1 inhibitors in breast cancer].

PubMed

Monneur, Audrey; Gonçalves, Anthony; Bertucci, François

2018-03-01

The development of immune checkpoints inhibitors represents one of the major recent advances in oncology. Monoclonal antibodies directed against the programmed cell death protein 1 (PD-1) or its ligand (PD-L1) provides durable disease control, particularly in melanoma, lung, kidney, bladder and head and neck cancers. The purpose of this review is to synthesize current data on the expression of PD-L1 in breast cancer and on the preliminary clinical results of PD-1/PD-L1 inhibitors in breast cancer patients. In breast cancer, PD-L1 expression is heterogeneous and is generally associated with the presence of tumor-infiltrating lymphocytes as well as the presence of poor-prognosis factors, such as young age, high grade, ER-negativity, PR-negativity, and HER-2 overexpression, high proliferative index, and aggressive molecular subtypes (triple negative, basal-like, HER-2-overexpressing). Its prognostic value remains controversial when assessed with immunohistochemistry, whereas it seems favorable in triple-negative cancers when assessed at the mRNA level. Early clinical trials with PD-1/PD-L1 inhibitors in breast cancer have shown efficacy in terms of tumor response and/or disease control in refractory metastatic breast cancers, notably in the triple-negative subtype. Many trials are currently underway, both in the metastatic and neo-adjuvant setting. A crucial issue is identification of biomarkers predictive of response to PD-1/PD-L1 inhibitors. Copyright © 2018 Société Française du Cancer. Published by Elsevier Masson SAS. All rights reserved.

Isolated perifacial lymph node metastasis in oral squamous cell carcinoma with clinically node-negative neck.

PubMed

Agarwal, Sangeet Kumar; Arora, Sowrabh Kumar; Kumar, Gopal; Sarin, Deepak

2016-10-01

The incidence of occult perifacial nodal disease in oral cavity squamous cell carcinoma is not well reported. The purpose of this study was to evaluate the incidence of isolated perifacial lymph node metastasis in patients with oral squamous cell carcinoma with a clinically node-negative neck. The study will shed light on current controversies and will provide valuable clinical and pathological information in the practice of routine comprehensive removal of these lymph node pads in selective neck dissection in the node-negative neck. Prospective analysis. This study was started in August 2011 when intraoperatively we routinely separated the lymph node levels from the main specimen for evaluation of the metastatic rate to different lymph node levels in 231 patients of oral squamous cell cancer with a clinically node-negative neck. The current study demonstrated that 19 (8.22%) out of 231 patients showed ipsilateral isolated perifacial lymph node involvement. The incidence of isolated perifacial nodes did not differ significantly between the oral tongue (7.14%) and buccal mucosa (7.75%). Incidence was statistically significant in cases with lower age group (<45 years), advanced T stage, and higher depth of tumor invasion. Isolated perifacial node metastasis is high in oral squamous cell carcinoma with a clinically node-negative neck. The incidence of isolated perifacial involvement is high in cases of buccal mucosal and tongue cancers. A meticulous dissection of the perifacial nodes seems prudent when treating the neck in oral cavity squamous cell carcinoma. 4 Laryngoscope, 126:2252-2256, 2016. © 2016 The American Laryngological, Rhinological and Otological Society, Inc.

Plasma source for spacecraft potential control

NASA Technical Reports Server (NTRS)

Olsen, R. C.

1983-01-01

A stable electrical ground which enables the particle spectrometers to measure the low energy particle populations was investigated and the current required to neutralize the spacecraft was measured. In addition, the plasma source for potential control (PSPO C) prevents high charging events which could affect the spacecraft electrical integrity. The plasma source must be able to emit a plasma current large enough to balance the sum of all other currents to the spacecraft. In ion thrusters, hollow cathodes provide several amperes of electron current to the discharge chamber. The PSPO C is capable of balancing the net negative currents found in eclipse charging events producing 10 to 100 microamps of electron current. The largest current required is the ion current necessary to balance the total photoelectric current.

Highly repeatable room temperature negative differential resistance in AlN/GaN resonant tunneling diodes grown by molecular beam epitaxy

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

Growden, Tyler A.; Fakhimi, Parastou; Berger, Paul R., E-mail: pberger@ieee.org

AlN/GaN resonant tunneling diodes grown on low dislocation density semi-insulating bulk GaN substrates via plasma-assisted molecular-beam epitaxy are reported. The devices were fabricated using a six mask level, fully isolated process. Stable room temperature negative differential resistance (NDR) was observed across the entire sample. The NDR exhibited no hysteresis, background light sensitivity, or degradation of any kind after more than 1000 continuous up-and-down voltage sweeps. The sample exhibited a ∼90% yield of operational devices which routinely displayed an average peak current density of 2.7 kA/cm{sup 2} and a peak-to-valley current ratio of ≈1.15 across different sizes.

AN EVALUATION OF THE INTERACTION BETWEEN QUALITY OF ATTENTION AND NEGATIVE REINFORCEMENT WITH CHILDREN WHO DISPLAY ESCAPE-MAINTAINED PROBLEM BEHAVIOR

PubMed Central

Gardner, Andrew W; Wacker, David P; Boelter, Eric W

2009-01-01

The choice-making behavior of 2 typically developing children who engaged in problem behavior maintained by negative reinforcement was evaluated within a concurrent-operants assessment that varied the quality of attention across free-play and demand conditions. The results demonstrated that it was possible to bias responding towards academic demands for both participants by providing high-quality attention, despite the continuous availability of negative reinforcement. The current study extended brief clinical methods with typically developing children and demonstrated how different qualities of attention provided across concurrent schedules could bias responding. PMID:19949522

Epidemiology, radiology, and genetics of nicotine dependence in COPD.

PubMed

Kim, Deog Kyeom; Hersh, Craig P; Washko, George R; Hokanson, John E; Lynch, David A; Newell, John D; Murphy, James R; Crapo, James D; Silverman, Edwin K

2011-01-13

Cigarette smoking is the principal environmental risk factor for developing COPD, and nicotine dependence strongly influences smoking behavior. This study was performed to elucidate the relationship between nicotine dependence, genetic susceptibility to nicotine dependence, and volumetric CT findings in smokers. Current smokers with COPD (GOLD stage ≥ 2) or normal spirometry were analyzed from the COPDGene Study, a prospective observational study. Nicotine dependence was determined by the Fagerstrom test for nicotine dependence (FTND). Volumetric CT acquisitions measuring the percent of emphysema on inspiratory CT (% of lung <-950 HU) and gas trapping on expiratory CT (% of lung <-856 HU) were obtained. Genotypes for two SNPs in the CHRNA3/5 region (rs8034191, rs1051730) previously associated with nicotine dependence and COPD were analyzed for association to COPD and nicotine dependence phenotypes. Among 842 currently smoking subjects (335 COPD cases and 507 controls), 329 subjects (39.1%) showed high nicotine dependence. Subjects with high nicotine dependence had greater cumulative and current amounts of smoking. However, emphysema severity was negatively correlated with the FTND score in controls (ρ = -0.19, p < .0001) as well as in COPD cases (ρ = -0.18, p = 0.0008). Lower FTND score, male gender, lower body mass index, and lower FEV1 were independent risk factors for emphysema severity in COPD cases. Both CHRNA3/5 SNPs were associated with FTND in current smokers. An association of genetic variants in CHRNA3/5 with severity of emphysema was only found in former smokers, but not in current smokers. Nicotine dependence was a negative predictor for emphysema on CT in COPD and control smokers. Increased inflammation in more highly addicted current smokers could influence the CT lung density distribution, which may influence genetic association studies of emphysema phenotypes.

Magnetic dipole discharges. II. Cathode and anode spot discharges and probe diagnostics

NASA Astrophysics Data System (ADS)

Stenzel, R. L.; Urrutia, J. M.; Ionita, C.; Schrittwieser, R.

2013-08-01

The high current regime of a magnetron-type discharge has been investigated. The discharge uses a permanent magnet as a cold cathode which emits secondary electrons while the chamber wall or a grounded electrode serves as the anode. As the discharge voltage is increased, the magnet develops cathode spots, which are short duration arcs that provide copious electrons to increase the discharge current dramatically. Short (1 μs), high current (200 A) and high voltage (750 V) discharge pulses are produced in a relaxation instability between the plasma and a charging capacitor. Spots are also observed on a negatively biased plane Langmuir probe. The probe current pulses are as large as those on the magnet, implying that the high discharge current does not depend on the cathode surface area but on the properties of the spots. The fast current pulses produce large inductive voltages, which can reverse the electrical polarity of the magnet and temporarily operate it as an anode. The discharge current may also oscillate at the frequency determined by the charging capacitor and the discharge circuit inductance. Each half cycle of high-current current pulses exhibits a fast (≃10 ns) current rise when a spot is formed. It induces high frequency (10-100 MHz) transients and ringing oscillations in probes and current circuits. Most probes behave like unmatched antennas for the electromagnetic pulses of spot discharges. Examples are shown to distinguish the source of oscillations and some rf characteristics of Langmuir probes.

Characterizing High School Students Who Play Drinking Games Using Latent Class Analysis

PubMed Central

Borsari, Brian; Zamboanga, Byron L.; Correia, Christopher; Olthuis, Janine V.; Van Tyne, Kathryne; Zadworny, Zoe; Grossbard, Joel R.; Horton, Nicholas J.

2013-01-01

Heavy alcohol use and its associated negative consequences continue to be an important health issue among adolescents. Of particular concern are risky drinking practices such as playing drinking games. Although retrospective accounts indicate that drinking game participation is common among high school students, it has yet to be assessed in current high school students. Utilizing data from high school students who reported current drinking game participation (n = 178), we used latent class analysis to investigate the negative consequences resulting from gaming and examined underlying demographic and alcohol-related behavioral characteristics of students as a function of the resultant classes. Three classes of “gamers” emerged: (1) a “lower-risk” group who had a lower probability of endorsing negative consequences compared to the other groups, (2) a “higher-risk” group who reported that they experienced hangovers and difficulties limiting their drinking, got physically sick, and became rude, obnoxious, or insulting, and (3) a “sexual regret” group who reported that they experienced poor recall and unplanned sexual activity that they later regretted. Although the frequency of participating in drinking games did not differ between these three groups, results indicated that the “lower-risk” group consumed fewer drinks in a typical gaming session compared to the other two groups. The present findings suggest that drinking games are common among high school students, but that mere participation and frequency of play is not necessarily the best indicator of risk. Instead, examination of other constructs such as game-related alcohol consumption, consequences, or psychosocial variables such as impulsivity may be more useful. PMID:23778317

Characterizing high school students who play drinking games using latent class analysis.

PubMed

Borsari, Brian; Zamboanga, Byron L; Correia, Christopher; Olthuis, Janine V; Van Tyne, Kathryne; Zadworny, Zoe; Grossbard, Joel R; Horton, Nicholas J

2013-10-01

Heavy alcohol use and its associated negative consequences continue to be an important health issue among adolescents. Of particular concern are risky drinking practices such as playing drinking games. Although retrospective accounts indicate that drinking game participation is common among high school students, it has yet to be assessed in current high school students. Utilizing data from high school students who reported current drinking game participation (n=178), we used latent class analysis to investigate the negative consequences resulting from gaming and examined underlying demographic and alcohol-related behavioral characteristics of students as a function of the resultant classes. Three classes of "gamers" emerged: (1) a "lower-risk" group who had a lower probability of endorsing negative consequences compared to the other groups, (2) a "higher-risk" group who reported that they experienced hangovers and difficulties limiting their drinking, got physically sick, and became rude, obnoxious, or insulting, and (3) a "sexual regret" group who reported that they experienced poor recall and unplanned sexual activity that they later regretted. Although the frequency of participating in drinking games did not differ between these three groups, results indicated that the "lower-risk" group consumed fewer drinks in a typical gaming session compared to the other two groups. The present findings suggest that drinking games are common among high school students, but that mere participation and frequency of play are not necessarily the best indicators of risk. Instead, examination of other constructs such as game-related alcohol consumption, consequences, or psychosocial variables such as impulsivity may be more useful. Copyright © 2013 Elsevier Ltd. All rights reserved.

Physiological modulators of Kv3.1 channels adjust firing patterns of auditory brain stem neurons.

PubMed

Brown, Maile R; El-Hassar, Lynda; Zhang, Yalan; Alvaro, Giuseppe; Large, Charles H; Kaczmarek, Leonard K

2016-07-01

Many rapidly firing neurons, including those in the medial nucleus of the trapezoid body (MNTB) in the auditory brain stem, express "high threshold" voltage-gated Kv3.1 potassium channels that activate only at positive potentials and are required for stimuli to generate rapid trains of actions potentials. We now describe the actions of two imidazolidinedione derivatives, AUT1 and AUT2, which modulate Kv3.1 channels. Using Chinese hamster ovary cells stably expressing rat Kv3.1 channels, we found that lower concentrations of these compounds shift the voltage of activation of Kv3.1 currents toward negative potentials, increasing currents evoked by depolarization from typical neuronal resting potentials. Single-channel recordings also showed that AUT1 shifted the open probability of Kv3.1 to more negative potentials. Higher concentrations of AUT2 also shifted inactivation to negative potentials. The effects of lower and higher concentrations could be mimicked in numerical simulations by increasing rates of activation and inactivation respectively, with no change in intrinsic voltage dependence. In brain slice recordings of mouse MNTB neurons, both AUT1 and AUT2 modulated firing rate at high rates of stimulation, a result predicted by numerical simulations. Our results suggest that pharmaceutical modulation of Kv3.1 currents represents a novel avenue for manipulation of neuronal excitability and has the potential for therapeutic benefit in the treatment of hearing disorders. Copyright © 2016 the American Physiological Society.

Physiological modulators of Kv3.1 channels adjust firing patterns of auditory brain stem neurons

PubMed Central

Brown, Maile R.; El-Hassar, Lynda; Zhang, Yalan; Alvaro, Giuseppe; Large, Charles H.

2016-01-01

Many rapidly firing neurons, including those in the medial nucleus of the trapezoid body (MNTB) in the auditory brain stem, express “high threshold” voltage-gated Kv3.1 potassium channels that activate only at positive potentials and are required for stimuli to generate rapid trains of actions potentials. We now describe the actions of two imidazolidinedione derivatives, AUT1 and AUT2, which modulate Kv3.1 channels. Using Chinese hamster ovary cells stably expressing rat Kv3.1 channels, we found that lower concentrations of these compounds shift the voltage of activation of Kv3.1 currents toward negative potentials, increasing currents evoked by depolarization from typical neuronal resting potentials. Single-channel recordings also showed that AUT1 shifted the open probability of Kv3.1 to more negative potentials. Higher concentrations of AUT2 also shifted inactivation to negative potentials. The effects of lower and higher concentrations could be mimicked in numerical simulations by increasing rates of activation and inactivation respectively, with no change in intrinsic voltage dependence. In brain slice recordings of mouse MNTB neurons, both AUT1 and AUT2 modulated firing rate at high rates of stimulation, a result predicted by numerical simulations. Our results suggest that pharmaceutical modulation of Kv3.1 currents represents a novel avenue for manipulation of neuronal excitability and has the potential for therapeutic benefit in the treatment of hearing disorders. PMID:27052580

Suppression of ambipolar current in tunnel FETs using drain-pocket: Proposal and analysis

NASA Astrophysics Data System (ADS)

Garg, Shelly; Saurabh, Sneh

2018-01-01

In this paper, we investigate the impact of a drain-pocket (DP) adjacent to the drain region in Tunnel Field-Effect Transistors (TFETs) to effectively suppress the ambipolar current. Using calibrated two-dimensional device simulation, we examine the impact of DP in Double Gate TFET (DGTFET). We demonstrate the superiority of the DP technique over the existing techniques in controlling the ambipolar current. In particular, the addition of DP to a TFET is able to fully suppress the ambipolar current even when TFET is biased at high negative gate voltages and drain doping is kept as high as the source doping. Moreover, adding DP is complementary to the well-known technique of employ-ing source-pocket (SP) in a TFET since both need similar doping type and doping concentration.

Trends in Physical Dating Violence Victimization among U.S. High School Students, 1999-2011

ERIC Educational Resources Information Center

Rothman, Emily F.; Xuan, Ziming

2014-01-01

Dating violence is a serious form of violence that places students at risk for injury, death, and negative mental health sequelae. The current analysis presents data on the prevalence of dating violence over a 12-year period among a nationally representative sample of high school-attending youth in the United States, stratified by race and gender.…

Targeted Nanoparticles for Image-guided Treatment of Triple Negative Breast Cancer: Clinical Significance and Technological Advances

PubMed Central

Miller-Kleinhenz, Jasmine M.; Bozeman, Erica N.

2015-01-01

Effective treatment of triple negative breast cancer (TNBC) with its aggressive tumor biology, highly heterogeneous tumor cells, and poor prognosis requires an integrated therapeutic approach that addresses critical issues in cancer therapy. Multifunctional nanoparticles with the abilities of targeted drug delivery and non-invasive imaging for monitoring drug delivery and responses to therapy, such as theranostic nanoparticles, hold great promise towards the development of novel therapeutic approaches for the treatment of TNBC using a single therapeutic platform. The biological and pathological characteristics of TNBC provide insight into several potential molecular targets for current and future nanoparticle based therapeutics. Extensive tumor stroma, highly proliferative cells, and a high rate of drug-resistance are all barriers that must be appropriately addressed in order for these nanotherapeutic platforms to be effective. Utilization of the enhanced permeability and retention (EPR) effect coupled with active targeting of cell surface receptors expressed by TNBC cells, and tumor associated endothelial cells, stromal fibroblasts and macrophages is likely to overcome such barriers to facilitate more effective drug delivery. An in depth summary of current studies investigating targeted nanoparticles in preclinical TNBC mouse and human xenograft models is presented. This review aims to outline the current status of nanotherapeutic options for TNBC patients, identification of promising molecular targets, challenges associated with the development of targeted nanotherapeutics, the research done by our group as well as others and future perspectives on the nanomedicine field and ways to translate current preclinical studies into the clinic. PMID:25966677

The Cadarache negative ion experiments

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

Massmann, P.; Bottereau, J.M.; Belchenko, Y.

1995-12-31

Up to energies of 140 keV neutral beam injection (NBI) based on positive ions has proven to be a reliable and flexible plasma heating method and has provided major contributions to most of the important experiments on virtually all large tokamaks around the world. As a candidate for additional heating and current drive on next step fusion machines (ITER ao) it is hoped that NBI can be equally successful. The ITER NBI parameters of 1 MeV, 50 MW D{degree} demand primary D{sup {minus}} beams with current densities of at least 15 mA/cm{sup 2}. Although considerable progress has been made inmore » the area of negative ion production and acceleration the high demands still require substantial and urgent development. Regarding negative ion production Cs seeded plasma sources lead the way. Adding a small amount of Cs to the discharge (Cs seeding) not only increases the negative ion yield by a factor 3--5 but also has the advantage that the discharge can be run at lower pressures. This is beneficial for the reduction of stripping losses in the accelerator. Multi-ampere negative ion production in a large plasma source is studied in the MANTIS experiment. Acceleration and neutralization at ITER relevant parameters is the objective of the 1 MV SINGAP experiment.« less

A-type voltage-gated K+ currents influence firing properties of isolectin B4-positive but not isolectin B4-negative primary sensory neurons.

PubMed

Vydyanathan, Amaresh; Wu, Zi-Zhen; Chen, Shao-Rui; Pan, Hui-Lin

2005-06-01

Voltage-gated K+ channels (Kv) in primary sensory neurons are important for regulation of neuronal excitability. The dorsal root ganglion (DRG) neurons are heterogeneous, and the types of native Kv currents in different groups of nociceptive DRG neurons are not fully known. In this study, we determined the difference in the A-type Kv current and its influence on the firing properties between isolectin B4 (IB4)-positive and -negative DRG neurons. Whole cell voltage- and current-clamp recordings were performed on acutely dissociated small DRG neurons of rats. The total Kv current density was significantly higher in IB+-positive than that in IB(4)-negative neurons. Also, 4-aminopyridine (4-AP) produced a significantly greater reduction in Kv currents in IB4-positive than in IB4-negative neurons. In contrast, IB4-negative neurons exhibited a larger proportion of tetraethylammonium-sensitive Kv currents. Furthermore, IB4-positive neurons showed a longer latency of firing and required a significantly larger amount of current injection to evoke action potentials. 4-AP significantly decreased the latency of firing and increased the firing frequency in IB4-positive but not in IB4-negative neurons. Additionally, IB4-positive neurons are immunoreactive to Kv1.4 but not to Kv1.1 and Kv1.2 subunits. Collectively, this study provides new information that 4-AP-sensitive A-type Kv currents are mainly present in IB4-positive DRG neurons and preferentially dampen the initiation of action potentials of this subpopulation of nociceptors. The difference in the density of A-type Kv currents contributes to the distinct electrophysiological properties of IB4-positive and -negative DRG neurons.

Reducing attentional capture of emotion by broadening attention: increased global attention reduces early electrophysiological responses to negative stimuli.

PubMed

Gable, Philip A; Harmon-Jones, Eddie

2012-05-01

Decades of research has shown the influence of emotion on attentional capture, and more recently, the influence of emotion on neurophysiological processes related to attentional capture. The current research tested whether some of the earliest neurophysiological underpinnings of emotive attentional processes can be influenced by attentional manipulations of broadening versus narrowing. Previous research has shown that negative affects high in motivational intensity (e.g., disgust, fear) cause a relative narrowing of attentional scope (Gable and Harmon-Jones, 2010a; Easterbrook, 1959). Because of the strong link between motivation and attention, attentional scope should also influence the attentional capture of negative stimuli. The current study manipulated a local attentional scope or global attentional scope, then measured attentional capture towards disgust and neutral pictures using the N1 event-related potential component. Results revealed that a manipulated global attentional scope reduced N1 amplitude towards disgust pictures compared to a manipulated local attentional scope. Copyright © 2012 Elsevier B.V. All rights reserved.

Human sex differences in emotional processing of own-race and other-race faces.

PubMed

Ran, Guangming; Chen, Xu; Pan, Yangu

2014-06-18

There is evidence that women and men show differences in the perception of affective facial expressions. However, none of the previous studies directly investigated sex differences in emotional processing of own-race and other-race faces. The current study addressed this issue using high time resolution event-related potential techniques. In total, data from 25 participants (13 women and 12 men) were analyzed. It was found that women showed increased N170 amplitudes to negative White faces compared with negative Chinese faces over the right hemisphere electrodes. This result suggests that women show enhanced sensitivity to other-race faces showing negative emotions (fear or disgust), which may contribute toward evolution. However, the current data showed that men had increased N170 amplitudes to happy Chinese versus happy White faces over the left hemisphere electrodes, indicating that men show enhanced sensitivity to own-race faces showing positive emotions (happiness). In this respect, men might use past pleasant emotional experiences to boost recognition of own-race faces.

Theoretical analysis of AlGaN/GaN resonant tunnelling diodes with step heterojunctions spacer and sub-quantum well

NASA Astrophysics Data System (ADS)

Liu, Y.; Gao, B.; Gong, M.

2017-06-01

In this paper, we proposed to use step heterojunctions emitter spacer (SHES) and InGaN sub-quantum well in AlGaN/GaN/AlGaN double barrier resonant tunnelling diodes (RTDs). Theoretical analysis of RTD with SHES and InGaN sub-quantum well was presented, which indicated that the negative differential resistance (NDR) characteristic was improved. And the simulation results, peak current density JP=82.67 mA/μm2, the peak-to-valley current ratio PVCR=3.38, and intrinsic negative differential resistance RN=-0.147Ω at room temperature, verified the improvement of NDR characteristic brought about by SHES and InGaN sub-quantum well. Both the theoretical analysis and simulation results showed that the device performance, especially the average oscillator output power presented great improvement and reached 2.77mW/μm2 magnitude. And the resistive cut-off frequency would benefit a lot from the relatively small RN as well. Our works provide an important alternative to the current approaches in designing new structure GaN based RTD for practical high frequency and high power applications.

Driven tracer with absolute negative mobility

NASA Astrophysics Data System (ADS)

Cividini, J.; Mukamel, D.; Posch, H. A.

2018-02-01

Instances of negative mobility, where a system responds to a perturbation in a way opposite to naive expectation, have been studied theoretically and experimentally in numerous nonequilibrium systems. In this work we show that absolute negative mobility (ANM), whereby current is produced in a direction opposite to the drive, can occur around equilibrium states. This is demonstrated with a simple one-dimensional lattice model with a driven tracer. We derive analytical predictions in the linear response regime and elucidate the mechanism leading to ANM by studying the high-density limit. We also study numerically a model of hard Brownian disks in a narrow planar channel, for which the lattice model can be viewed as a toy model. We find that the model exhibits negative differential mobility (NDM), but no ANM.

Effect of plasma grid bias on extracted currents in the RF driven surface-plasma negative ion source

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

Belchenko, Yu., E-mail: belchenko@inp.nsk.su; Ivanov, A.; Sanin, A.

2016-02-15

Extraction of negative ions from the large inductively driven surface-plasma negative ion source was studied. The dependencies of the extracted currents vs plasma grid (PG) bias potential were measured for two modifications of radio-frequency driver with and without Faraday screen, for different hydrogen feeds and for different levels of cesium conditioning. The maximal PG current was independent of driver modification and it was lower in the case of inhibited cesium. The maximal extracted negative ion current depends on the potential difference between the near-PG plasma and the PG bias potentials, while the absolute value of plasma potential in the drivermore » and in the PG area is less important for the negative ion production. The last conclusion confirms the main mechanism of negative ion production through the surface conversion of fast atoms.« less

Bias-stress characterization of solution-processed organic field-effect transistor based on highly ordered liquid crystals

NASA Astrophysics Data System (ADS)

Kunii, M.; Iino, H.; Hanna, J.

2017-06-01

Bias-stress effects in solution-processed, 2-decyl-7-phenyl-[1]benzothieno[3,2-b][1]benzothiophene (Ph-BTBT-10) field effect transistors (FETs) are studied under negative and positive direct current bias. The bottom gate, bottom contact polycrystalline Ph-BTBT-10 FET with a hybrid gate dielectric of polystyrene and SiO2 shows high field effect mobility as well as a steep subthreshold slope when fabricated with a highly ordered smectic E liquid crystalline (SmE) film as a precursor. Negative gate bias-stress causes negative threshold voltage shift (ΔVth) for Ph-BTBT-10 FET in ambient air, but ΔVth rapidly decreases as the gate bias decreases and approaches to near zero when the gate bias goes down to 9 V in amplitude. In contrast, positive gate bias-stress causes negligible ΔVth even with a relatively high bias voltage. These results conclude that Ph-BTBT-10 FET has excellent bias-stress stability in ambient air in the range of low to moderate operating voltages.

Is outcome responsibility at work emotionally exhausting? Investigating employee proactivity as a moderator.

PubMed

Schmitt, Antje; Den Hartog, Deanne N; Belschak, Frank D

2015-10-01

This study investigates the relationship between outcome responsibility and employees' well-being in terms of emotional exhaustion. Outcome responsibility is a job demand implying that employees' decisions at work have high material and/or nonmaterial consequences. Previous research indicates that outcome responsibility can have both positive and negative effects on employee well-being. Based on the person-job fit approach we hypothesize that whether or not outcome responsibility is positively or negatively related to emotional exhaustion depends on whether employees' behavioral style fits with this job demand. We investigate the role of proactive behavior as a personal resource that fits with high responsibility. We test our hypothesis in a multisource study among 138 employee-colleague dyads. Results of hierarchical moderated regression analysis reveal that peer-rated proactive behavior moderates the relationship between outcome responsibility and emotional exhaustion, such that the relationship is negative for employees showing high and nonsignificant for employees showing low proactivity. This finding holds also when controlling for trait positive and negative affect. The current study contributes to previous research on job design, proactivity, and occupational well-being and offers practical implications in terms of selection and training of employees for jobs high in outcome responsibility. (c) 2015 APA, all rights reserved).

NASCAP modelling of high-voltage power system interactions with space charged-particle environments

NASA Technical Reports Server (NTRS)

Stevens, N. J.; Roche, J. C.; Mandell, M. J.

1979-01-01

A simple space power system operating in geosynchronous orbit was analyzed. This system consisted of two solar array wings and a central body. Each solar array wing was considered to be divided into three regions operating at 2000 volts. The center body was considered to be an electrical ground with the array voltages both positive and negative relative to ground. The system was analyzed for both a normal environment and a moderate geomagnetic substorm environment. Initial results indicate a high probability of arcing at the interconnects on the negative operating voltage wing. The dielectric strength of the substrate may be exceeded giving rise to breakdown in the bulk of the material. The geomagnetic substorm did not seem to increase the electrical gradients at the interconnects on the negative operating voltage wing but did increase the gradients on the positive operating voltage wing which could result in increased coupling current losses.

High performance current and spin diode of atomic carbon chain between transversely symmetric ribbon electrodes.

PubMed

Dong, Yao-Jun; Wang, Xue-Feng; Yang, Shuo-Wang; Wu, Xue-Mei

2014-08-21

We demonstrate that giant current and high spin rectification ratios can be achieved in atomic carbon chain devices connected between two symmetric ferromagnetic zigzag-graphene-nanoribbon electrodes. The spin dependent transport simulation is carried out by density functional theory combined with the non-equilibrium Green's function method. It is found that the transverse symmetries of the electronic wave functions in the nanoribbons and the carbon chain are critical to the spin transport modes. In the parallel magnetization configuration of two electrodes, pure spin current is observed in both linear and nonlinear regions. However, in the antiparallel configuration, the spin-up (down) current is prohibited under the positive (negative) voltage bias, which results in a spin rectification ratio of order 10(4). When edge carbon atoms are substituted with boron atoms to suppress the edge magnetization in one of the electrodes, we obtain a diode with current rectification ratio over 10(6).

High performance current and spin diode of atomic carbon chain between transversely symmetric ribbon electrodes

PubMed Central

Dong, Yao-Jun; Wang, Xue-Feng; Yang, Shuo-Wang; Wu, Xue-Mei

2014-01-01

We demonstrate that giant current and high spin rectification ratios can be achieved in atomic carbon chain devices connected between two symmetric ferromagnetic zigzag-graphene-nanoribbon electrodes. The spin dependent transport simulation is carried out by density functional theory combined with the non-equilibrium Green's function method. It is found that the transverse symmetries of the electronic wave functions in the nanoribbons and the carbon chain are critical to the spin transport modes. In the parallel magnetization configuration of two electrodes, pure spin current is observed in both linear and nonlinear regions. However, in the antiparallel configuration, the spin-up (down) current is prohibited under the positive (negative) voltage bias, which results in a spin rectification ratio of order 104. When edge carbon atoms are substituted with boron atoms to suppress the edge magnetization in one of the electrodes, we obtain a diode with current rectification ratio over 106. PMID:25142376

Three-dimensional modeling of a negative ion source with a magnetic filter: impact of biasing the plasma electrode on the plasma asymmetry

NASA Astrophysics Data System (ADS)

Fubiani, G.; Boeuf, J. P.

2015-10-01

The effect on the plasma characteristics of biasing positively the plasma electrode (PE) in negative ion sources with a magnetic filter is analysed using a 3D particle-in-cell model with Monte-Carlo collisions (PIC-MCC). We specialize to the one driver (i.e. one inductively coupled radio-frequency discharge) BATMAN negative ion source and the 4-drivers (large volume) ELISE device. Both are ITER prototype high power tandem-type negative ion sources developed for the neutral beam injector (NBI) system. The plasma is generated in the driver and diffuses inside the second chamber which is magnetized. Asymmetric plasma profiles originate from the formation of an electric field transverse to the electron current flowing through the magnetic filter (Hall effect). The model shows that the importance of the asymmetry increases with the PE bias potential, i.e. with the electron flow from the driver to the extraction region and depends on the shape of the magnetic filter field. We find that although the plasma density and potential profiles may be more or less asymmetric depending on the filter field configuration, the electron current to the plasma grid is always strongly asymmetric.

Valley current characterization of high current density resonant tunnelling diodes for terahertz-wave applications

NASA Astrophysics Data System (ADS)

Jacobs, K. J. P.; Stevens, B. J.; Baba, R.; Wada, O.; Mukai, T.; Hogg, R. A.

2017-10-01

We report valley current characterisation of high current density InGaAs/AlAs/InP resonant tunnelling diodes (RTDs) grown by metal-organic vapour phase epitaxy (MOVPE) for THz emission, with a view to investigate the origin of the valley current and optimize device performance. By applying a dual-pass fabrication technique, we are able to measure the RTD I-V characteristic for different perimeter/area ratios, which uniquely allows us to investigate the contribution of leakage current to the valley current and its effect on the PVCR from a single device. Temperature dependent (20 - 300 K) characteristics for a device are critically analysed and the effect of temperature on the maximum extractable power (PMAX) and the negative differential conductance (NDC) of the device is investigated. By performing theoretical modelling, we are able to explore the effect of typical variations in structural composition during the growth process on the tunnelling properties of the device, and hence the device performance.

Larkspur poisoning of cattle: Current knowledge and research

USDA-ARS?s Scientific Manuscript database

Larkspurs (Delphinium species) are native poisonous plants that negatively impact the earning potential of beef producers on many western rangelands. If ranchers are unfortunate enough to have large stands of toxic larkspur in their pastures, yearly herd mortality can be as high as 10%. This results...

The Image of Africa in Our Classrooms.

ERIC Educational Resources Information Center

Pahl, Ronald H.

1995-01-01

Argues that the media portrayal of Africa remains highly selective, focusing almost solely on negative and violent stories. Positive stories (local initiatives, political reform) go unreported as does much of the Western powers involvement in famine and destruction. Includes a list of sources on African current affairs. (MJP)

It gets better with time: Enhancement of age-related positivity effect in the six months following a highly negative public event.

PubMed

Ford, Jaclyn H; DiBiase, Haley D; Ryu, Ehri; Kensinger, Elizabeth A

2018-05-01

Age is associated with shifts toward more positive memory retrieval. The current study examined these shifts following a negative public event. Participants completed two surveys examining emotional responses to the 2013 Boston Marathon bombings, one immediately following the attack and another 6 months later. Age was associated with different effects of time on how individuals reflected on this event. Time was associated with an increased focus on negative components in young adults but a decreased focus in older adults. These findings reveal a role of time in age-related positivity effects. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Summary of Almost 20 Years of Storm Overflight Electric Field, Conductivity, Flash Rate, and Current Statistics

NASA Technical Reports Server (NTRS)

Blakeslee, Richard J.; Mach, Douglas M.; Bateman, Monte J.; Bailey, Jeffrey C.

2011-01-01

We present total conduction (Wilson) currents for more than 1000 high-altitude aircraft overflights of electrified clouds acquired over nearly two decades. The overflights include a wide geographical sample of storms over land and ocean, with and without lightning, and with positive (i.e., upward-directed) and negative current. Peak electric field, with lightning transients removed, ranged from -1.0 kV/m to 16. kV/m, with mean (median) of 0.9 kV/m (0.29 kV/m). Total conductivity at flight altitude ranged from 0.6 pS/m to 3.6 pS/m, with mean and median of 2.2 pS/m. Peak current densities ranged from -2.0 nA m(exp -2) to 33.0 nA m(exp -2) with mean (median) of 1.9 nA m(exp -2) (0.6 nA m(exp -2)). Total upward current flow from storms in our dataset ranged from -1.3 to 9.4 A. The mean current for storms with lightning is 1.7 A over ocean and 1.0 A over land. The mean current for electrified shower clouds (i.e. electrified storms without lightning) is 0.41 A for ocean and 0.13 A for land. About 78% (43%) of the land (ocean) storms have detectable lightning. Land storms have 2.8 times the mean flash rate as ocean storms (2.2 versus 0.8 flashes min-1, respectively). Approximately 7% of the overflights had negative current. The mean and median currents for positive (negative) polarity storms are 1.0 and 0.35 A (-0.30 and -0.26 A). We found no regional or latitudinal-based patterns in our storm currents, nor support for simple scaling laws between cloud top height and lightning flash rate.

Summary of Almost 20 Years of Storm Overflight Electric Field, Conductivity, Flash Rates, and Electric Current Statistics

NASA Technical Reports Server (NTRS)

Blakeslee, Richard J.; Mach, Douglas M.; Bateman, Monte J.; Bailey, Jeffrey C.

2011-01-01

We determined total conduction currents and flash rates for around 900 high-altitude aircraft overflights of electrified clouds over 17 years. The overflights include a wide geographical sample of storms over land and ocean, with and without lightning, and with positive (i.e., upward-directed) and negative current. Peak electric field, with lightning transients removed, ranged from -1.0 kV m(sup -1) to 16. kV m(sup -1), with mean (median) of 0.9 kV m(sup -1) (0.29 kV m(sup -1)). Total conductivity at flight altitude ranged from 0.6 pS m(sup -1) to 3.6 pS m(sup -1), with mean and median of 2.2 pS m(sup -1). Peak current densities ranged from -2.0 nA m(sup -2) to 33.0 nA m(sup -2) with mean (median) of 1.9 nA m(sup -2) (0.6 nA m(sup -2)). Total upward current flow from storms in our dataset ranged from -1.3 to 9.4 A. The mean current for storms with lightning is 1.6 A over ocean and 1.0 A over land. The mean current for electrified shower clouds (i.e. electrified storms without lightning) is 0.39 A for ocean and 0.13 A for land. About 78% (43%) of the land (ocean) storms have detectable lightning. Land storms have 2.8 times the mean flash rate as ocean storms (2.2 versus 0.8 flashes min(sup -1), respectively). Approximately 7% of the overflights had negative current. The mean and median currents for positive (negative) polarity storms are 1.0 and 0.35 A (-0.30 and -0.26 A). We found no regional or latitudinal-based patterns in our storm currents, nor support for simple scaling laws between cloud top height and lightning flash rate.

Modeling of negative ion extraction from a magnetized plasma source: Derivation of scaling laws and description of the origins of aberrations in the ion beam

NASA Astrophysics Data System (ADS)

Fubiani, G.; Garrigues, L.; Boeuf, J. P.

2018-02-01

We model the extraction of negative ions from a high brightness high power magnetized negative ion source. The model is a Particle-In-Cell (PIC) algorithm with Monte-Carlo Collisions. The negative ions are generated only on the plasma grid surface (which separates the plasma from the electrostatic accelerator downstream). The scope of this work is to derive scaling laws for the negative ion beam properties versus the extraction voltage (potential of the first grid of the accelerator) and plasma density and investigate the origins of aberrations on the ion beam. We show that a given value of the negative ion beam perveance correlates rather well with the beam profile on the extraction grid independent of the simulated plasma density. Furthermore, the extracted beam current may be scaled to any value of the plasma density. The scaling factor must be derived numerically but the overall gain of computational cost compared to performing a PIC simulation at the real plasma density is significant. Aberrations appear for a meniscus curvature radius of the order of the radius of the grid aperture. These aberrations cannot be cancelled out by switching to a chamfered grid aperture (as in the case of positive ions).

Design and fabrication of GaAs OMIST photodetector

NASA Astrophysics Data System (ADS)

Kang, Xuejun; Lin, ShiMing; Liao, Qiwei; Gao, Junhua; Liu, Shi'an; Cheng, Peng; Wang, Hongjie; Zhang, Chunhui; Wang, Qiming

1998-08-01

We designed and fabricated GaAs OMIST (Optical-controlled Metal-Insulator-Semiconductor Thyristor) device. Using oxidation of AlAs layer that is grown by MBE forms the Ultra- Thin semi-Insulating layer (UTI) of the GAAS OMIST. The accurate control and formation of high quality semi-insulating layer (AlxOy) are the key processes for fabricating GaAs OMIST. The device exhibits a current-controlled negative resistance region in its I-V characteristics. When illuminated, the major effect of optical excitation is the reduction of the switching voltage. If the GaAs OMIST device is biased at a voltage below its dark switching voltage Vs, sufficient incident light can switch OMIST from high impedance low current 'off' state to low impedance high current 'on' state. The absorbing material of OMIST is GaAS, so if the wavelength of incident light within 600 to approximately 850 nm can be detected effectively. It is suitable to be used as photodetector for digital optical data process. The other attractive features of GaAs OMIST device include suitable conducted current, switching voltage and power levels for OEIC, high switch speed and high sensitivity to light or current injection.

Curious Case of Positive Current Collectors: Corrosion and Passivation at High Temperature.

PubMed

Sayed, Farheen N; Rodrigues, Marco-Tulio F; Kalaga, Kaushik; Gullapalli, Hemtej; Ajayan, P M

2017-12-20

In the evaluation of compatibility of different components of cell for high-energy and extreme-conditions applications, the highly focused are positive and negative electrodes and their interaction with electrolyte. However, for high-temperature application, the other components are also of significant influence and contribute toward the total health of battery. In present study, we have investigated the behavior of aluminum, the most common current collector for positive electrode materials for its electrochemical and temperature stability. For electrochemical stability, different electrolytes, organic and room temperature ionic liquids with varying Li salts (LiTFSI, LiFSI), are investigated. The combination of electrochemical and spectroscopic investigations reflects the varying mechanism of passivation at room and high temperature, as different compositions of decomposed complexes are found at the surface of metals.

Impulsivity and Alcohol-Related Risk among College Students: Examining Urgency, Sensation Seeking and the Moderating Influence of Beliefs about Alcohol's Role in the College Experience

PubMed Central

LaBrie, Joseph W.; Kenney, Shannon R.; Napper, Lucy E.; Miller, Kevin

2013-01-01

The personality trait of impulsivity is predictive of heavy drinking and consequences among college students. The current study examined how impulsivity—measured via positive urgency, negative urgency, and sensation seeking—and a person's beliefs about the role alcohol plays in the college experience relate to drinking and consequences in a sample of 470 college students (mean age = 19 years, 61.3% female, 59.8% white). In support of hypotheses, sensation seeking independently predicted greater drinking, and both positive and negative urgency predicted greater experience of alcohol-related negative consequences after controlling for consumption level. Moreover, alcohol beliefs moderated the relationship between impulsivity types and alcohol outcomes. Among students high (versus low) in sensation seeking, strong beliefs about alcohol's role in college life were related to significantly greater drinking, and among students high (versus low) in negative urgency, endorsing strong beliefs about alcohol's role in college life were related to greater levels of alcohol-related negative consequences. Overall, findings inform college prevention efforts by highlighting the need to distinguish unique facets of impulsivity and examine how they intersect with students’ beliefs about alcohol in college. PMID:24120644

Impulsivity and alcohol-related risk among college students: examining urgency, sensation seeking and the moderating influence of beliefs about alcohol's role in the college experience.

PubMed

LaBrie, Joseph W; Kenney, Shannon R; Napper, Lucy E; Miller, Kevin

2014-01-01

The personality trait of impulsivity is predictive of heavy drinking and consequences among college students. The current study examined how impulsivity-measured via positive urgency, negative urgency, and sensation seeking-and a person's beliefs about the role alcohol plays in the college experience relate to drinking and consequences in a sample of 470 college students (mean age=19 years, 61.3% female, 59.8% White). In support of the hypotheses, sensation seeking independently predicted greater drinking, and both positive urgency and negative urgency predicted greater experience of alcohol-related negative consequences after controlling for consumption level. Moreover, alcohol beliefs moderated the relationship between impulsivity types and alcohol outcomes. Among students high (versus low) in sensation seeking, strong beliefs about alcohol's role in college life were related to significantly greater drinking, and among students high (versus low) in negative urgency, endorsing strong beliefs about alcohol's role in college life were related to greater levels of alcohol-related negative consequences. Overall, findings inform college prevention efforts by highlighting the need to distinguish unique facets of impulsivity and examine how they intersect with students' beliefs about alcohol in college. © 2013.

Observation of X-rays from long laboratory negative discharge in STP air

NASA Astrophysics Data System (ADS)

Kochkin, Pavlo; van Deursen, A. P. J.; Ebert, Ute

2014-05-01

Pulses of x-rays emitted by lightning are one of the most intriguing among unsolved problem in physics of lightning. They have been detected from both - natural and rocket-triggered lightning. In natural lightning x-rays were detected during stepped leader process and later were associated with a single step. In triggered lighting x-rays were found to be originated from a tip of a dart leader that also possesses stepping propagation mechanism. Therefore, stepping mechanism is the key to understanding the x-ray pulses generated by lightning. Unfortunately, leader stepping mechanism itself is far from well understood. Negative long laboratory discharges also develop through a formation of a space stem/leader and they also generate bursts of x-ray radiation. In this study we investigate the development of a long negative laboratory spark in particular focusing on its x-ray emission. A 2 MV Marx generator delivers high-voltage standard lightning pulse with 1.2/50 microsec rise/fall time to a spark gap with conical electrodes. The distance between cone tips was varied between 1 m and 1.75 m. An upper voltage limit is set to about 1 MV level. The voltage is measured by capacitive high-voltage divider. Two Pearson 7427 current probes determine the currents through high-voltage and grounded electrodes. Two LaBr3 scintillator detectors were mounted in EMC-cabinets and recorded the x-rays. Picos4 Stanford Optics camera with intensified CCD is placed in 4 m distance from the spark gap and directed perpendicular to the spark plane. The camera allows us to make ns-fast images of pre-breakdown phenomena in controllable time. We discovered new details of space stem/leader formation and development in long laboratory sparks. The connection moment of positive part of the space stem/leader to negative high-voltage is accompanied by intense x-ray emission. Taking into account our previous study on positive discharge, we conclude that encounter between positive and negative streamers is the most likely mechanism responsible for the x-rays.

Preparative isolation and purification of antioxidative diarylheptanoid derivatives from Alnus japonica by high-speed counter-current chromatography.

PubMed

Lim, Soon Sung; Lee, Min Young; Ahn, Hong Ryul; Choi, Soon Jung; Lee, Jae-Yong; Jung, Sang Hoon

2011-12-01

This study employed the online HPLC-2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS)(+) bioassay to rapidly determine the antioxidant compounds occurring in the crude extract of Alnus japonica. The negative peaks of the ABTS(+) radical scavenging detection system, which indicated the presence of antioxidant activity, were monitored by measuring the decrease in absorbance at 734 nm. The ABTS(+)-based antioxidant activity profile showed that three negative peaks exhibited antioxidant activity. High-speed counter-current chromatography (HSCCC) was used for preparative scale separation of the three active peaks from the extract. The purity of the isolated compounds was analyzed by HPLC and their structures were identified by (1)H- and (13)C-nuclear magnetic resonance spectrometry (NMR), heteronuclear multiple bond correlation (HMBC), and heteronuclear single quantum correlation (HSQC). Two solvent systems composed of n-hexane/ethylacetate/methanol/water (4:6:4:6, v/v) and of ethyl acetate/methanol/water (1:0.1:1, v/v) were performed in high-speed counter-current chromatography. Consequently, a total of 527 mg of hirsutanonol 5-O-β-D-glucopyranoside, 80.04 mg of 3-deoxohirsutenonol 5-O-β-D-glucopyranoside, and 91.0 mg of hirsutenone were obtained with purity of 94.7, 90.5, and 98.6%, respectively. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Characteristics of the high-rate discharge capability of a nickel/metal hydride battery electrode

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

Geng, M.; Han, J.; Feng, F.

1999-10-01

The high rate discharge capability of the negative electrode in a Ni/MH battery is mainly determined by the charge transfer process at the interface between the metal hydride (MH) alloy powder and the electrolyte, and the mass transfer process in the bulk MH alloy powder. In this study, the anodic polarization curves of a MH electrode were measured and analyzed. An alloy of nominal composition Mm{sub 0.95}Ti{sub 0.05}Ni{sub 3.85}Co{sub 0.45}Mn{sub 0.35}Al{sub 0.35} was used as the negative electrode material. With increasing number of charge/discharge cycles, the MH alloy powders microcrack into particles several micrometers in diameter. The decrease in themore » MH alloy particle size results in an increase in both the activation surface area and the exchange current density of the MH alloy electrode. The electrode overpotentials of the MH electrode decreases with increasing number of cycles at a large value of anodic polarization current. The decrease in electrode overpotential leads to an increase in the high rate discharge capability of the MH electrode. By using the limiting current, the hydrogen diffusion coefficient in the MH alloy was estimated to be 1.2 x 10{sup {minus}11}cm{sup 2}s{sup {minus}1} assuming an average particle radius of 5 {micro}m.« less

Development of Low Parasitic Light Sensitivity and Low Dark Current 2.8 μm Global Shutter Pixel †

PubMed Central

Yokoyama, Toshifumi; Tsutsui, Masafumi; Suzuki, Masakatsu; Nishi, Yoshiaki; Mizuno, Ikuo; Lahav, Assaf

2018-01-01

We developed a low parasitic light sensitivity (PLS) and low dark current 2.8 μm global shutter pixel. We propose a new inner lens design concept to realize both low PLS and high quantum efficiency (QE). 1/PLS is 7700 and QE is 62% at a wavelength of 530 nm. We also propose a new storage-gate based memory node for low dark current. P-type implants and negative gate biasing are introduced to suppress dark current at the surface of the memory node. This memory node structure shows the world smallest dark current of 9.5 e−/s at 60 °C. PMID:29370146

Development of Low Parasitic Light Sensitivity and Low Dark Current 2.8 μm Global Shutter Pixel.

PubMed

Yokoyama, Toshifumi; Tsutsui, Masafumi; Suzuki, Masakatsu; Nishi, Yoshiaki; Mizuno, Ikuo; Lahav, Assaf

2018-01-25

Abstract : We developed a low parasitic light sensitivity (PLS) and low dark current 2.8 μm global shutter pixel. We propose a new inner lens design concept to realize both low PLS and high quantum efficiency (QE). 1/PLS is 7700 and QE is 62% at a wavelength of 530 nm. We also propose a new storage-gate based memory node for low dark current. P-type implants and negative gate biasing are introduced to suppress dark current at the surface of the memory node. This memory node structure shows the world smallest dark current of 9.5 e - /s at 60 °C.

Unemotional on all counts: Evidence of reduced affective responses in individuals with high callous-unemotional traits across emotion systems and valences.

PubMed

Fanti, Kostas A; Panayiotou, Georgia; Lombardo, Michael V; Kyranides, Melina Nicole

2016-01-01

The current study aimed to identify atypical neurophysiological activity associated with deficient affective processing in individuals with high callous-unemotional traits (CU). Fifty-six participants (M age = 20.52; 46% male) divided in two groups, differentiated on levels of CU traits, were invited to participate in the experimental phase of the study. Medial prefrontal cortex activity, measured with functional Near-Infrared Spectroscopy, and facial electro-myography activity were recorded during videos depicting violent, comedy and neutral scenes. Individuals high on CU traits showed similar medial prefrontal cortex oxygenated hemoglobin (HbO(2)) activity to positive and negative films, while the pre-frontal cortical responses of low CU individuals were more pronounced to positive than negative materials. High CU participants also showed reduced facial electromyography at the corrugator muscle in response to violent films, which was not differentiated from their responses to comedy films. These findings suggest that individuals high on CU traits show reduced but not absent (i.e., flat) affect to emotional material. Deficits in processing positive and negative valent material, measured with different neuro-physiological modalities, might be essential to understand CU traits.

Improving the Stability of High-Performance Multilayer MoS2 Field-Effect Transistors.

PubMed

Liu, Na; Baek, Jongyeol; Kim, Seung Min; Hong, Seongin; Hong, Young Ki; Kim, Yang Soo; Kim, Hyun-Suk; Kim, Sunkook; Park, Jozeph

2017-12-13

In this study, we propose a method for improving the stability of multilayer MoS 2 field-effect transistors (FETs) by O 2 plasma treatment and Al 2 O 3 passivation while sustaining the high performance of bulk MoS 2 FET. The MoS 2 FETs were exposed to O 2 plasma for 30 s before Al 2 O 3 encapsulation to achieve a relatively small hysteresis and high electrical performance. A MoO x layer formed during the plasma treatment was found between MoS 2 and the top passivation layer. The MoO x interlayer prevents the generation of excess electron carriers in the channel, owing to Al 2 O 3 passivation, thereby minimizing the shift in the threshold voltage (V th ) and increase of the off-current leakage. However, prolonged exposure of the MoS 2 surface to O 2 plasma (90 and 120 s) was found to introduce excess oxygen into the MoO x interlayer, leading to more pronounced hysteresis and a high off-current. The stable MoS 2 FETs were also subjected to gate-bias stress tests under different conditions. The MoS 2 transistors exhibited negligible decline in performance under positive bias stress, positive bias illumination stress, and negative bias stress, but large negative shifts in V th were observed under negative bias illumination stress, which is attributed to the presence of sulfur vacancies. This simple approach can be applied to other transition metal dichalcogenide materials to understand their FET properties and reliability, and the resulting high-performance hysteresis-free MoS 2 transistors are expected to open up new opportunities for the development of sophisticated electronic applications.

Measuring skin conductance over clothes.

PubMed

Hong, Ki Hwan; Lee, Seung Min; Lim, Yong Gyu; Park, Kwang Suk

2012-11-01

We propose a new method that measures skin conductance over clothes to nonintrusively monitor the changes in physiological conditions affecting skin conductance during daily activities. We selected the thigh-to-thigh current path and used an indirectly coupled 5-kHz AC current for the measurement. While varying the skin conductance by the Valsalva maneuver method, the results were compared with the traditional galvanic skin response (GSR) measured directly from the fingers. Skin conductance measured using a 5-kHz current displayed a highly negative correlation with the traditional GSR and the current measured over clothes reflected the rate of change of the conductance of the skin beneath.

Characteristics of the NASA Lewis bumpy torus plasma generated with high positive or negative applied potentials

NASA Technical Reports Server (NTRS)

Roth, J. R.; Gerdin, G. A.

1976-01-01

The toroidal ring of plasma contained in the NASA Lewis bumpy-torus superconducting magnet facility may be biased to positive or negative potentials approaching 50 kilovolts by applying direct-current voltages of the respective polarity to 12 or fewer of the midplane electrode rings. The electric fields which are responsible for heating the ions by E/B drift then point radially outward or inward. The low-frequency fluctuations below the ion cyclotron frequency appeared to be dominated by rotating spokes.

Use of mTOR inhibitors in the treatment of breast cancer: an evaluation of factors that influence patient outcomes

PubMed Central

Jerusalem, Guy; Rorive, Andree; Collignon, Joelle

2014-01-01

Many systemic treatment options are available for advanced breast cancer, including endocrine therapy, chemotherapy, anti-human epidermal growth factor receptor 2 (HER2) therapy, and other targeted agents. Recently, everolimus, a mammalian target of rapamycin (mTOR) inhibitor, combined with exemestane, an aromatase inhibitor, has been approved in Europe and the USA for patients suffering from estrogen receptor-positive, HER2-negative advanced breast cancer previously treated by a nonsteroidal aromatase inhibitor, based on the results of BOLERO-2 (Breast cancer trials of OraL EveROlimus). This study showed a statistically significant and clinically meaningful improvement in median progression-free survival. Results concerning the impact on overall survival are expected in the near future. This clinically oriented review focuses on the use of mTOR inhibitors in breast cancer. Results reported with first-generation mTOR inhibitors (ridaforolimus, temsirolimus, everolimus) are discussed. The current and potential role of mTOR inhibitors is reported according to breast cancer subtype (estrogen receptor-positive HER2-negative, triple-negative, and HER2-positive ER-positive/negative disease). Everolimus is currently being evaluated in the adjuvant setting in high-risk estrogen receptor-positive, HER2-negative early breast cancer. Continuing mTOR inhibition or alternatively administering other drugs targeting the phosphatidylinositol-3-kinase/protein kinase B-mTOR pathway after progression on treatments including an mTOR inhibitor is under evaluation. Potential biomarkers to select patients showing a more pronounced benefit are reviewed, but we are not currently using these biomarkers in routine practice. Subgroup analysis of BOLERO 2 has shown that the benefit is consistent in all subgroups and that it is impossible to select patients not benefiting from addition of everolimus to exemestane. Side effects and impact on quality of life are other important issues discussed in this review. Second-generation mTOR inhibitors and dual mTOR-phosphatidylinositol-3-kinase inhibitors are currently being evaluated in clinical trials. PMID:24833916

Negative urgency mediates the relationship between childhood maltreatment and problems with alcohol and cannabis in late adolescence

PubMed Central

Wardell, Jeffrey D.; Strang, Nicole M.; Hendershot, Christian S.

2017-01-01

Background Childhood maltreatment is an important risk factor for problems with alcohol and other drugs such as cannabis. Although this link has been well established, the mechanisms in this association require further study. High levels of impulsivity and difficulties with emotion regulation are often associated with childhood maltreatment. Negative urgency – an emotion-based facet of impulsivity – is a strong predictor of substance use problems and may be a particularly relevant facet of impulsivity in the link between childhood maltreatment and alcohol and cannabis outcomes. However, few studies have examined the specific mediational pathway from childhood maltreatment to alcohol and cannabis problems through negative urgency. Objectives We tested the hypothesis that the associations between history of childhood maltreatment and current alcohol and cannabis problems would be mediated by negative urgency, but not other facets of impulsivity. Methods Participants (N=232), who were in late adolescence (mean age=19.75), completed self-report measures of different facets of impulsivity, past childhood maltreatment, and current alcohol and cannabis use and problems. Results In analyses including several facets of impulsivity as simultaneous mediators, negative urgency was the only facet to mediate the associations of childhood maltreatment severity with alcohol and cannabis problems. Conclusions These findings provide support for negative urgency as a unique mediator of the association between childhood maltreatment and both alcohol and cannabis problems, suggesting that future work on mechanisms in this association should focus on mood-based impulsivity. PMID:26774820

Hybrid lead-acid battery with reticulated vitreous carbon as a carrier- and current-collector of negative plate

NASA Astrophysics Data System (ADS)

Czerwiński, A.; Obrębowski, S.; Kotowski, J.; Rogulski, Z.; Skowroński, J.; Bajsert, M.; Przystałowski, M.; Buczkowska-Biniecka, M.; Jankowska, E.; Baraniak, M.; Rotnicki, J.; Kopczyk, M.

Bare reticulated vitreous carbon (RVC) plated electrochemically with thin layer of lead was investigated as a negative plate carrier- and current-collector material for lead-acid batteries. Hybrid flooded single cell lead-acid batteries containing one negative plate based on a new type (RVC or Pb/RVC) of carrier/current-collector and two positive plates based on Pb-Ca grid collectors were assembled and subjected to charge/discharge tests (at 20-h and 1-h discharge rates) and Peukert's dependences determination. The promising results show that application of RVC as carrier- and current-collector in negative plate will significantly increase the specific capacity of lead-acid battery.

SUPPLEMENTAL ULTRAVIOLET-B RADIATION DOES NOT REDUCE GROWTH OR GRAIN YIELD IN RICE

EPA Science Inventory

Negative effects of enhanced UV-B radiation have been demonstrated in plants, but impacts under realistic field conditions remain uncertain. Adverse impacts to major crops, such as rice (Oryza sativa L.), that are grown in areas with currently high ambient levels of UV-B, could h...

High resolution techno-ecological modeling of a bioenergy landscape to identify climate mitigation opportunities in cellulosic ethanol production

USDA-ARS?s Scientific Manuscript database

Meeting current biofuel mandates or creating future carbon-negative biopower systems requires feedstocks be sourced in sufficient quantities at low cost and with minimal environmental impact. Cultivating perennial grasses on low-quality lands is a promising feedstock supply strategy minimizing on-...

High School Students' Attitudes towards Spiders: A Cross-Cultural Comparison

ERIC Educational Resources Information Center

Prokop, Pavol; Tolarovicova, Andrea; Camerik, Anne M.; Peterkova, Viera

2010-01-01

Spiders are traditionally considered to be among the least popular of animals. Current evidence suggests that a negative attitude towards spiders could be influenced by both cultural and evolutionary pressures. Some researchers suggest that science education activities could positively influence students' perceptions of spiders. Their evidence is,…

Smoking, HIV, and risk of pregnancy loss.

PubMed

Westreich, Daniel; Cates, Jordan; Cohen, Mardge; Weber, Kathleen M; Seidman, Dominika; Cropsey, Karen; Wright, Rodney; Milam, Joel; Young, Mary A; Mehta, C Christina; Gustafson, Deborah R; Golub, Elizabeth T; Fischl, Margaret A; Adimora, Adaora A

2017-02-20

Cigarette smoking during pregnancy increases risks of poor pregnancy outcomes including miscarriage and stillbirth (pregnancy loss), but the effect of smoking on pregnancy loss among HIV-infected women has not been explored. Here, investigated the impact of smoking on risk of pregnancy loss among HIV-positive and HIV-negative women, and estimated the potential impact of realistic smoking cessation interventions on risk of pregnancy loss among HIV-positive women. We analyzed pregnancy outcomes in HIV-positive and HIV-negative participants in the Women's Interagency HIV Study between 1994 and 2014. We estimated effects of current smoking at or immediately before pregnancy on pregnancy loss; we controlled for confounding using regression approaches, and estimated potential impact of realistic smoking cessation interventions using a semiparametric g-formula approach. Analysis examined 1033 pregnancies among 659 women. The effect of smoking on pregnancy loss differed dramatically by HIV status: adjusted for confounding, the risk difference comparing current smokers to current nonsmokers was 19.2% (95% confidence limit 10.9-27.5%) in HIV-positive women and 9.7% (95% confidence limit 0.0-19.4%) in HIV-negative women. These results were robust to sensitivity analyses. We estimated that we would need to offer a realistic smoking cessation intervention to 36 women to prevent one pregnancy loss. Smoking is a highly prevalent exposure with important consequences for pregnancy in HIV-positive pregnant women in the United States, even in the presence of potent highly active antiretroviral therapy. This evidence supports greater efforts to promote smoking cessation interventions among HIV-positive women, especially those who desire to become pregnant.

The role of current affect, anticipated affect and spontaneous self-affirmation in decisions to receive self-threatening genetic risk information.

PubMed

Ferrer, Rebecca A; Taber, Jennifer M; Klein, William M P; Harris, Peter R; Lewis, Katie L; Biesecker, Leslie G

2015-01-01

One reason for not seeking personally threatening information may be negative current and anticipated affective responses. We examined whether current (e.g., worry) and anticipated negative affect predicted intentions to seek sequencing results in the context of an actual genomic sequencing trial (ClinSeq®; n = 545) and whether spontaneous self-affirmation mitigated any (negative) association between affect and intentions. Anticipated affective response negatively predicted intentions to obtain and share results pertaining to both medically actionable and non-actionable disease, whereas current affect was only a marginal predictor. The negative association between anticipated affect and intentions to obtain results pertaining to non-actionable disease was weaker in individuals who were higher in spontaneous self-affirmation. These results have implications for the understanding of current and anticipated affect, self-affirmation and consequential decision-making and contribute to a growing body of evidence on the role of affect in medical decisions.

Self-criticism, dependency, and stress reactivity: an experience sampling approach to testing Blatt and Zuroff's (1992) theory of personality predispositions to depression in high-risk youth.

PubMed

Adams, Philippe; Abela, John R Z; Auerbach, Randy; Skitch, Steven

2009-11-01

S. J. Blatt and D. C. Zuroff's 1992 theory of personality predispositions to depression posits that individuals who possess high levels of self-criticism and/or dependency are vulnerable to developing depression following negative events. The current study used experience sampling methodology to test this theory in a sample of 49 children ages 7 to 14. Children completed measures of dependency, self-criticism, and depressive symptoms. Subsequently, children were given a handheld computer that signaled them to complete measures of depressive symptoms and negative events at randomly selected times over 2 months. Results of hierarchical linear modeling analyses indicated that higher levels of both self-criticism and dependency were associated with greater elevations in depressive symptoms following negative events. Furthermore, each personality predisposition remained a significant predictor of such elevations after controlling for the interaction between the other personality predisposition and negative events. The results suggest that dependency and self-criticism represent distinct vulnerability factors to depression in youth.

Cost-effectiveness of digital subtraction angiography in the setting of computed tomographic angiography negative subarachnoid hemorrhage.

PubMed

Jethwa, Pinakin R; Punia, Vineet; Patel, Tapan D; Duffis, E Jesus; Gandhi, Chirag D; Prestigiacomo, Charles J

2013-04-01

Recent studies have documented the high sensitivity of computed tomography angiography (CTA) in detecting a ruptured aneurysm in the presence of acute subarachnoid hemorrhage (SAH). The practice of digital subtraction angiography (DSA) when CTA does not reveal an aneurysm has thus been called into question. We examined this dilemma from a cost-effectiveness perspective by using current decision analysis techniques. A decision tree was created with the use of TreeAge Pro Suite 2012; in 1 arm, a CTA-negative SAH was followed up with DSA; in the other arm, patients were observed without further imaging. Based on literature review, costs and utilities were assigned to each potential outcome. Base-case and sensitivity analyses were performed to determine the cost-effectiveness of each strategy. A Monte Carlo simulation was then conducted by sampling each variable over a plausible distribution to evaluate the robustness of the model. With the use of a negative predictive value of 95.7% for CTA, observation was found to be the most cost-effective strategy ($6737/Quality Adjusted Life Year [QALY] vs $8460/QALY) in the base-case analysis. One-way sensitivity analysis demonstrated that DSA became the more cost-effective option if the negative predictive value of CTA fell below 93.72%. The Monte Carlo simulation produced an incremental cost-effectiveness ratio of $83 083/QALY. At the conventional willingness-to-pay threshold of $50 000/QALY, observation was the more cost-effective strategy in 83.6% of simulations. The decision to perform a DSA in CTA-negative SAH depends strongly on the sensitivity of CTA, and therefore must be evaluated at each center treating these types of patients. Given the high sensitivity of CTA reported in the current literature, performing DSA on all patients with CTA negative SAH may not be cost-effective at every institution.

Dietary salt consumption and the knowledge, attitudes and behavior of healthy adults: a cross-sectional study from Jordan.

PubMed

Alawwa, Izzat; Dagash, Rajaa; Saleh, Akram; Ahmad, Abdelaziz

2018-12-01

High dietary sodium is recognized as a silent killer responsible for 2.3 million deaths worldwide in 2010 predominantly secondary to hypertension and its complications. Although high salt consumption is considered a worldwide public health problem, its magnitude is highly variable among different communities; therefore, it is important to study locally. This study aimed to evaluate habitual salt consumption, its important correlations, as well as the knowledge, attitude, and behavior of healthy Jordanian citizens. As potassium consumption is highly correlated and important we aimed to study both jointly. In this descriptive cross-sectional study we enrolled 103 healthy adult Jordanian citizens. All participants were interviewed for questionnaire filling, physical examination, and instructed on proper 24-hour urine collection procedure. We measured sodium and potassium concentration in the provided controlled 24-hour urine collection samples, as it is presently considered the gold standard for evaluating daily intake. The results showed an average sodium intake of 179 mmol (4.1 g) per day [higher in males at 186 mmol (4.3 g) vs. 173 mmol (4.0 g) for females], significantly above the current WHO recommendations, though only 8% regularly add salt to food. Ironically, most participants (82%) believe their salt consumption was appropriate and only 29% thought they may benefit from reducing salt intake. On the other hand, potassium intake is far below the current WHO recommendations. High sodium and low potassium intake have synergistic adverse effects on public health that is not currently addressed in Jordan. We conclude that Jordanian citizens currently consume high sodium and low potassium diet and are mostly unaware of its negative impact on their health. Hence, it is crucial for healthcare providers to intervene and adopt long-term strategies to control salt intake to reduce its negative effects in Jordan and elsewhere.

Enhancing the Developmental Appropriateness of Treatment for Depression in Youth: Integrating the Family in Treatment

PubMed Central

Tompson, Martha C.; Boger, Kathryn Dingman; Asarnow, Joan R.

2016-01-01

Youth depression is an impairing and frequently recurrent and persistent disorder that impacts current and later development, resulting in high social and economic costs. Depression and interpersonal stress are frequently transactional, with depression powerfully negatively impacting relationships and relationship stress negatively impacting the course and outcome of depression. In this context, treatment models for youth depression that emphasize interpersonal functioning, particularly family relationships, may be particularly promising. This article has three objectives. It first reviews the current state of knowledge on the efficacy of psychosocial treatments for depression in youth, with an emphasis on the role of family involvement in treatment. Second, it discusses developmental factors that may impact the applicability and structure of family-focused treatment models for preadolescent and adolescent youth. Third, two family-based treatment models that are currently being evaluated in randomized clinical trials are described: one focusing on preadolescent depressed youth and the other on adolescents who have made a recent suicide attempt. PMID:22537731

The value of a transformation zone component in anal cytology to detect HSIL.

PubMed

Roberts, Jennifer M; Jin, Fengyi; Thurloe, Julia K; Ekman, Deborah; Adams, Marjorie K; McDonald, Ross L; Biro, Clare; Poynten, I Mary; Grulich, Andrew E; Farnsworth, Annabelle

2016-08-01

In a cytology-based screening program intended to prevent anal cancer, the anal transformation zone (TZ) should be adequately sampled because it is the site most susceptible to the development of the cancer precursor, high-grade squamous intraepithelial lesion (HSIL). An adequate TZ component is defined as comprising at least 10 rectal columnar or squamous metaplastic cells. In the current study, the authors examined whether the presence of a TZ component in anal cytology correlated with the detection of histological HSIL. In a natural history study of anal human papillomavirus infection in homosexual men, all participants underwent liquid-based cytology and high-resolution anoscopy (HRA) with or without biopsy at each visit. True-negative cytology (negative cytology with non-HSIL biopsy or negative HRA), false-negative cytology (negative cytology with HSIL biopsy), and true-positive cytology (abnormal cytology with HSIL biopsy) were compared with regard to the presence or absence of a TZ component. Of 617 participants, baseline results included 155 true-positive results, 191 true-negative results, and 31 false-negative results. The absence of an adequate TZ component was found to be significantly higher for false-negative (32.3%) than for either true-positive (11.0%; P = .0034) or true-negative (13.1%; P = .0089) results. Significantly more false-negative cases lacked a TZ component compared with either true-positive or true-negative cases. TZ cells may be an important indicator of sample quality for anal cytology because, unlike cervical sampling, the anal canal is not visualized during cytology sampling. Cancer Cytopathol 2016;124:596-601. © 2016 American Cancer Society. © 2016 American Cancer Society.

Effect of atomic layer deposition temperature on current conduction in Al2O3 films formed using H2O oxidant

NASA Astrophysics Data System (ADS)

Hiraiwa, Atsushi; Matsumura, Daisuke; Kawarada, Hiroshi

2016-08-01

To develop high-performance, high-reliability gate insulation and surface passivation technologies for wide-bandgap semiconductor devices, the effect of atomic layer deposition (ALD) temperature on current conduction in Al2O3 films is investigated based on the recently proposed space-charge-controlled field emission model. Leakage current measurement shows that Al2O3 metal-insulator-semiconductor capacitors formed on the Si substrates underperform thermally grown SiO2 capacitors at the same average field. However, using equivalent oxide field as a more practical measure, the Al2O3 capacitors are found to outperform the SiO2 capacitors in the cases where the capacitors are negatively biased and the gate material is adequately selected to reduce virtual dipoles at the gate/Al2O3 interface. The Al2O3 electron affinity increases with the increasing ALD temperature, but the gate-side virtual dipoles are not affected. Therefore, the leakage current of negatively biased Al2O3 capacitors is approximately independent of the ALD temperature because of the compensation of the opposite effects of increased electron affinity and permittivity in Al2O3. By contrast, the substrate-side sheet of charge increases with increasing ALD temperature above 210 °C and hence enhances the current of positively biased Al2O3 capacitors more significantly at high temperatures. Additionally, an anomalous oscillatory shift of the current-voltage characteristics with ALD temperature was observed in positively biased capacitors formed by low-temperature (≤210 °C) ALD. This shift is caused by dipoles at the Al2O3/underlying SiO2 interface. Although they have a minimal positive-bias leakage current, the low-temperature-grown Al2O3 films cause the so-called blisters problem when heated above 400 °C. Therefore, because of the absence of blistering, a 450 °C ALD process is presently the most promising technology for growing high-reliability Al2O3 films.

Targeted nanoparticles for image-guided treatment of triple-negative breast cancer: clinical significance and technological advances.

PubMed

Miller-Kleinhenz, Jasmine M; Bozeman, Erica N; Yang, Lily

2015-01-01

Effective treatment of triple-negative breast cancer (TNBC) with its aggressive tumor biology, highly heterogeneous tumor cells, and poor prognosis requires an integrated therapeutic approach that addresses critical issues in cancer therapy. Multifunctional nanoparticles with the abilities of targeted drug delivery and noninvasive imaging for monitoring drug delivery and responses to therapy, such as theranostic nanoparticles, hold great promise toward the development of novel therapeutic approaches for the treatment of TNBC using a single therapeutic platform. The biological and pathological characteristics of TNBC provide insight into several potential molecular targets for current and future nanoparticle-based therapeutics. Extensive tumor stroma, highly proliferative cells, and a high rate of drug resistance are all barriers that must be appropriately addressed in order for these nanotherapeutic platforms to be effective. Utilization of the enhanced permeability and retention effect coupled with active targeting of cell surface receptors expressed by TNBC cells, and tumor-associated endothelial cells, stromal fibroblasts, and macrophages is likely to overcome such barriers to facilitate more effective drug delivery. An in-depth summary of current studies investigating targeted nanoparticles in preclinical TNBC mouse and human xenograft models is presented. This review aims to outline the current status of nanotherapeutic options for TNBC patients, identification of promising molecular targets, challenges associated with the development of targeted nanotherapeutics, the research done by our group as well as by others, and future perspectives on the nanomedicine field and ways to translate current preclinical studies into the clinic. © 2015 Wiley Periodicals, Inc.

System integration of RF based negative ion experimental facility at IPR

NASA Astrophysics Data System (ADS)

Bansal, G.; Bandyopadhyay, M.; Singh, M. J.; Gahlaut, A.; Soni, J.; Pandya, K.; Parmar, K. G.; Sonara, J.; Chakraborty, A.

2010-02-01

The setting up of RF based negative ion experimental facility shall witness the beginning of experiments on the negative ion source fusion applications in India. A 1 MHz RF generator shall launch 100 kW RF power into a single driver on the plasma source to produce a plasma of density ~5 × 1012 cm-3. The source can deliver a negative ion beam of ~10 A with a current density of ~30 mA/cm2 and accelerated to 35 kV through an electrostatic ion accelerator. The experimental system is similar to a RF based negative ion source, BATMAN, presently operating at IPP. The subsystems for source operation are designed and procured principally from indigenous resources, keeping the IPP configuration as a base line. The operation of negative ion source is supported by many subsystems e.g. vacuum pumping system with gate valves, cooling water system, gas feed system, cesium delivery system, RF generator, high voltage power supplies, data acquisition and control system, and different diagnostics. The first experiments of negative ion source are expected to start at IPR from the middle of 2009.

Negative (but not Positive) Parenting Interacts with Infant Negative Affect to Predict Infant Approach: Evidence of Diathesis-Stress.

PubMed

Holzman, Jacob B; Burt, Nicole M; Edwards, Erin S; Rosinski, Leanna D; Bridgett, David J

2018-01-01

Temperament by parenting interactions may reflect that individuals with greater risk are more likely to experience negative outcomes in adverse contexts (diathesis-stress) or that these individuals are more susceptible to contextual influences in a 'for better or for worse' pattern (differential susceptibility). Although such interactions have been identified for a variety of child outcomes, prior research has not examined approach characteristics - excitement and approach toward pleasurable activities - in the first year of life. Therefore, the current study investigated whether 6-month maternal reported infant negative affect - a phenotypic marker of risk/susceptibility - interacted with 8-month observed parenting behaviors (positive parenting, negative parenting) to predict 12-month infant behavioral approach. Based a sample of mothers and their infants ( N =150), results indicated that negative parenting was inversely associated with subsequent approach for infants with high, but not low, levels of early negative affect. Similar results did not occur regarding positive parenting. These findings better fit a diathesis-stress model rather than a differential susceptibility model. Implications and limitations of these findings are discussed.

Effects of interpretation training on hostile attribution bias and reactivity to interpersonal insult.

PubMed

Hawkins, Kirsten A; Cougle, Jesse R

2013-09-01

Research suggests that individuals high in anger have a bias for attributing hostile intentions to ambiguous situations. The current study tested whether this interpretation bias can be altered to influence anger reactivity to an interpersonal insult using a single-session cognitive bias modification program. One hundred thirty-five undergraduate students were randomized to receive positive training, negative training, or a control condition. Anger reactivity to insult was then assessed. Positive training led to significantly greater increases in positive interpretation bias relative to the negative group, though these increases were only marginally greater than the control group. Negative training led to increased negative interpretation bias relative to other groups. During the insult, participants in the positive condition reported less anger than those in the control condition. Observers rated participants in the positive condition as less irritated than those in the negative condition and more amused than the other two conditions. Though mediation of effects via bias modification was not demonstrated, among the positive condition posttraining interpretation bias was correlated with self-reported anger, suggesting that positive training reduced anger reactivity by influencing interpretation biases. Findings suggest that positive interpretation training may be a promising treatment for reducing anger. However, the current study was conducted with a non-treatment-seeking student sample; further research with a treatment-seeking sample with problematic anger is necessary. Copyright © 2013. Published by Elsevier Ltd.

Exploring the Relationship between Negative Urgency and Dysregulated Eating: Etiologic Associations and the Role of Negative Affect

PubMed Central

Racine, Sarah E.; Keel, Pamela K.; Burt, S. Alexandra; Sisk, Cheryl L.; Neale, Michael; Boker, Steven; Klump, Kelly L.

2013-01-01

Negative urgency (i.e., the tendency to engage in rash action in response to negative affect) has emerged as a critical personality trait contributing to individual differences in binge eating. However, studies investigating the extent to which genetic and/or environmental influences underlie the effects of negative urgency on binge eating are lacking. Moreover, it remains unclear whether negative urgency-binge eating associations are simply due to the well-established role of negative affect in the development/maintenance of binge eating. The current study addresses these gaps by examining phenotypic and etiologic associations between negative urgency, negative affect, and dysregulated eating (i.e., binge eating, emotional eating) in a sample of 222 same-sex female twin pairs from the Michigan State Twin Registry. Negative urgency was significantly associated with both dysregulated eating symptoms, even after controlling for the effects of negative affect. Genetic factors accounted for the majority (62–77%) of this phenotypic association, although a significant proportion of this genetic covariation was due to genetic influences in common with negative affect. Non-shared environmental factors accounted for a relatively smaller (23–38%) proportion of the association, but these non-shared environmental effects were independent of negative affect. Findings suggest that the presence of emotion-based rash action, combined with high levels of negative affect, may significantly increase genetic risk for dysregulated eating. PMID:23356217

Exploring the relationship between negative urgency and dysregulated eating: etiologic associations and the role of negative affect.

PubMed

Racine, Sarah E; Keel, Pamela K; Burt, S Alexandra; Sisk, Cheryl L; Neale, Michael; Boker, Steven; Klump, Kelly L

2013-05-01

Negative urgency (i.e., the tendency to engage in rash action in response to negative affect) has emerged as a critical personality trait contributing to individual differences in binge eating. However, studies investigating the extent to which genetic and/or environmental influences underlie the effects of negative urgency on binge eating are lacking. Moreover, it remains unclear whether negative urgency-binge eating associations are simply a result of the well-established role of negative affect in the development/maintenance of binge eating. The current study addresses these gaps by examining phenotypic and etiologic associations between negative urgency, negative affect, and dysregulated eating (i.e., binge eating, emotional eating) in a sample of 222 same-sex female twin pairs from the Michigan State University Twin Registry. Negative urgency was significantly associated with both dysregulated eating symptoms, even after controlling for the effects of negative affect. Genetic factors accounted for the majority (62-77%) of this phenotypic association, although a significant proportion of this genetic covariation was due to genetic influences in common with negative affect. Nonshared environmental factors accounted for a relatively smaller (23-38%) proportion of the association, but these nonshared environmental effects were independent of negative affect. Findings suggest that the presence of emotion-based rash action, combined with high levels of negative affect, may significantly increase genetic risk for dysregulated eating. © 2013 American Psychological Association

Recruiting at the Edge: Kinetic Energy Inhibits Anchovy Populations in the Western Mediterranean

PubMed Central

Ruiz, Javier; Macías, Diego; Rincón, Margarita M.; Pascual, Ananda; Catalán, Ignacio A.; Navarro, Gabriel

2013-01-01

The Strait of Gibraltar replenishes the Mediterranean with Atlantic waters through an intense eastward current known as the Atlantic Jet (AJ). The AJ fertilizes the southwestern Mediterranean and is considered to be the ultimate factor responsible for the comparatively high fish production of this region. Here, we perform an analysis of the available historical catches and catch per unit effort (CPUE), together with a long series of surface currents, kinetic energy and chlorophyll concentration. We show that the high kinetic energy of the AJ increases primary production but also negatively impacts the recruitment of anchovy. We contend that anchovy recruitment in the region is inhibited by the advection and dispersion of larvae and post-larvae during periods of strong advection by the AJ. The inhibitory impact of kinetic energy on anchovy landings is not a transient but rather a persistent state of the system. An exceptional combination of events creates an outbreak of this species in the Alboran Sea. These events depend on the Mediterranean-Atlantic exchange of water masses and, therefore, are highly sensitive to climate changes that are projected, though not always negatively, for fish landings. PMID:23451027

An adaptable walking-skid for seabed ROV under strong current disturbance

NASA Astrophysics Data System (ADS)

Si, Jianting; Chin, Chengsiong

2014-09-01

This paper proposed a new concept of an adaptable multi-legged skid design for retro-fitting to a remotely-operated vehicle (ROV) during high tidal current underwater pipeline inspection. The sole reliance on propeller-driven propulsion for ROV is replaced with a proposed low cost biomimetic solution in the form of an attachable hexapod walking skid. The advantage of this adaptable walking skid is the high stability in positioning and endurances to strong current on the seabed environment. The computer simulation flow studies using Solidworks Flow Simulation shown that the skid attachment in different compensation postures caused at least four times increase in overall drag, and negative lift forces on the seabed ROV to achieve a better maneuvering and station keeping under the high current condition (from 0.5 m/s to 5.0 m/s). A graphical user interface is designed to interact with the user during robot-in-the-loop testing and kinematics simulation in the pool.

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

Huesemann, Michael H.

It is currently believed that science and technology can provide effective solutions to most, if not all, environmental problems facing western industrial societies. The validity of this optimistic assumption is highly questionable for at least three reasons: First, current mechanistic, reductionist science is inherently incapable of providing the complete and accurate information which is required to successfully address environmental problems. Second, both the conservation of mass principle and the second law of thermodynamics dictate that most remediation technologies - while successful in solving specific pollution problems - cause unavoidable negative environmental impacts elsewhere or in the future. Third, it ismore » intrinsically impossible to design industrial processes that have no negative environmental impacts. This follows not only from the entropy law but also from the fact that any generation of energy is impossible without negative environmental consequences. It can therefore be concluded that science and technology have only very limited potential in solving current and future environmental problems. Consequently, it will be necessary to address the root cause of environmental deterioration, namely the prevailing materialistic values that are the main driving force for both overpopulation and overconsumption. The long-term protection of the environment is therefore not primarily a technical problem but rather a social and moral problem that can only be solved by drastically reducing the strong influence of materialistic values.« less

Direct negative chronotropic action of desflurane on sinoatrial node pacemaker activity in the guinea pig heart.

PubMed

Kojima, Akiko; Ito, Yuki; Kitagawa, Hirotoshi; Matsuura, Hiroshi; Nosaka, Shuichi

2014-06-01

Desflurane inhalation is associated with sympathetic activation and concomitant increase in heart rate in humans and experimental animals. There is, however, little information concerning the direct effects of desflurane on electrical activity of sinoatrial node pacemaker cells that determines the intrinsic heart rate. Whole-cell patch-clamp experiments were conducted on guinea pig sinoatrial node pacemaker cells to record spontaneous action potentials and ionic currents contributing to sinoatrial node automaticity, namely, hyperpolarization-activated cation current (If), T-type and L-type Ca currents (ICa,T and ICa,L, respectively), Na/Ca exchange current (INCX), and rapidly and slowly activating delayed rectifier K currents (IKr and IKs, respectively). Electrocardiograms were recorded from ex vivo Langendorff-perfused hearts and in vivo hearts. Desflurane at 6 and 12% decreased spontaneous firing rate of sinoatrial node action potentials by 15.9% (n = 11) and 27.6% (n = 10), respectively, which was associated with 20.4% and 42.5% reductions in diastolic depolarization rate, respectively. Desflurane inhibited If, ICa,T, ICa,L, INCX, and IKs but had little effect on IKr. The negative chronotropic action of desflurane was reasonably well reproduced in sinoatrial node computer model. Desflurane reduced the heart rate in Langendorff-perfused hearts. High concentration (12%) of desflurane inhalation was associated with transient tachycardia, which was totally abolished by pretreatment with the β-adrenergic blocker propranolol. Desflurane has a direct negative chronotropic action on sinoatrial node pacemaking activity, which is mediated by its inhibitory action on multiple ionic currents. This direct inhibitory action of desflurane on sinoatrial node automaticity seems to be counteracted by sympathetic activation associated with desflurane inhalation in vivo.

Room temperature microwave oscillations in GaN/AlN resonant tunneling diodes with peak current densities up to 220 kA/cm2

NASA Astrophysics Data System (ADS)

Encomendero, Jimy; Yan, Rusen; Verma, Amit; Islam, S. M.; Protasenko, Vladimir; Rouvimov, Sergei; Fay, Patrick; Jena, Debdeep; Xing, Huili Grace

2018-03-01

We report the generation of room temperature microwave oscillations from GaN/AlN resonant tunneling diodes, which exhibit record-high peak current densities. The tunneling heterostructure grown by molecular beam epitaxy on freestanding GaN substrates comprises a thin GaN quantum well embedded between two AlN tunneling barriers. The room temperature current-voltage characteristics exhibit a record-high maximum peak current density of ˜220 kA/cm2. When biased within the negative differential conductance region, microwave oscillations are measured with a fundamental frequency of ˜0.94 GHz, generating an output power of ˜3.0 μW. Both the fundamental frequency and the output power of the oscillator are limited by the external biasing circuit. Using a small-signal equivalent circuit model, the maximum intrinsic frequency of oscillation for these diodes is predicted to be ˜200 GHz. This work represents a significant step towards microwave power generation enabled by resonant tunneling transport, an ultra-fast process that goes beyond the limitations of current III-Nitride high electron mobility transistors.

High Current Plasma Electrolytic Oxidation Coating Processes for Wear and Corrosion Prevention of Al 2024

NASA Astrophysics Data System (ADS)

Wang, Rui

Plasma electrolytic oxidation (PEO) treatments have been used in the aerospace and automotive industries because the coating formed on light metals or alloys has great hardness, high wear, corrosion, and oxidation resistance, and a low friction coefficient that improves lifetime length and provide a higher surface quality. However, the PEO treatments that are presently used for industrial applications require a long period of time to confirm the quality of the coating. For this reason, the present study seeks to increase the current density of PEO treatments to improve their efficiency and explore the performance of the obtained coatings. It was found that for high current density (0.18A/cm2) PEO treatments, smaller ratio, such as 50% and 70%, is beneficial to obtaining a better performance coating. When compared with the coating of a "normal" (current density: 0.09A/cm2) PEO treatment, it had better wear resistance; however, for corrosion resistance, it had a lower performance than the coatings obtained by the "normal" current density PEO treatment which was attributed to the negative influence of porosity increase.

Giant anisotropic magnetoresistance and planar Hall effect in the Dirac semimetal Cd3As2

NASA Astrophysics Data System (ADS)

Li, Hui; Wang, Huan-Wen; He, Hongtao; Wang, Jiannong; Shen, Shun-Qing

2018-05-01

Anisotropic magnetoresistance is the change tendency of resistance of a material on the mutual orientation of the electric current and the external magnetic field. Here, we report experimental observations in the Dirac semimetal Cd3As2 of giant anisotropic magnetoresistance and its transverse version, called the planar Hall effect. The relative anisotropic magnetoresistance is negative and up to -68% at 2 K and 10 T. The high anisotropy and the minus sign in this isotropic and nonmagnetic material are attributed to a field-dependent current along the magnetic field, which may be induced by the Berry curvature of the band structure. This observation not only reveals unusual physical phenomena in Weyl and Dirac semimetals, but also finds additional transport signatures of Weyl and Dirac fermions other than negative magnetoresistance.

Is androgen receptor targeting an emerging treatment strategy for triple negative breast cancer?

PubMed

Anestis, Aristomenis; Karamouzis, Michalis V; Dalagiorgou, Georgia; Papavassiliou, Athanasios G

2015-06-01

Triple negative breast cancer (TNBC) is an aggressive breast cancer subtype. The absence of expression and/or amplification of estrogen and progesterone receptor as well as ERBB-2 prevent the use of currently available endocrine options and/or ERBB-2-directed drugs and indicates chemotherapy as the main current therapy. TNBC represents approximately 15% of breast cancer cases with high index of heterogeneity. Here, we review the role of androgen receptor in breast carcinogenesis and its association with alterations in the expression pattern and functional roles of regulatory molecules and signal transduction pathways in TNBC. Additionally, based on the so far preclinical and clinical published data, we evaluate the perspectives for using and/or developing androgen receptor targeting strategies for specific TNBC subtypes. Copyright © 2015 Elsevier Ltd. All rights reserved.

Numerical Analysis of the Temperature Impact on Performance of GaN-Based 460-nm Light-Emitting Diode.

PubMed

Tawfik, Wael Z; Lee, June Key

2018-03-01

The influence of temperature on the characteristics of a GaN-based 460-nm light-emitting diode (LED) prepared on sapphire substrate was simulated using the SiLENSe and SpeCLED software programs. High temperatures impose negative effects on the performance of GaN-based LEDs. As the temperature increases, electrons acquire higher thermal energies, and therefore LEDs may suffer more from high-current loss mechanisms, which in turn causes a reduction in the radiative recombination rate in the active region. The internal quantum efficiency was reduced by about 24% at a current density of 35 A/cm2, and the electroluminescence spectral peak wavelength was redshifted. The LED operated at 260 K and exhibited its highest light output power of ~317.5 mW at a maximum injection current of 350 mA, compared to 212.2 mW for an LED operated at 400 K. However, increasing temperature does not cause a droop in efficiency under high injection conditions. The peak efficiency at 1 mA of injection current decreases more rapidly by ~15% with increasing temperature from 260 to 400 K than the efficiency at high injection current of 350 mA by ~11%.

Observation of coherent diffractive charged current interactions of antineutrinos on neon nuclei

NASA Astrophysics Data System (ADS)

Marage, P.; Aderholz, M.; Armenise, N.; Azemoon, T.; Barnham, K. W. J.; Bartley, J. H.; Baton, J. P.; Bertrand, D.; Brisson, V.; Bullock, F. W.; Calicchio, M.; Cooper, A. M.; Chwastowski, J.; Clayton, E. F.; Coghen, T.; Erriquez, O.; Fitch, P. J.; Gerbier, G.; Guy, J.; Hulth, P. O.; Jones, G. T.; Kasper, P.; Kochowski, C.; Leighton-Davies, S.; Middleton, R. P.; Mobayyen, M. M.; Morrison, D. R. O.; Neveu, M.; Nuzzo, S.; O'Neale, S. W.; Parker, M. A.; Petiau, P.; Ruggieri, F.; Sacton, J.; Sansum, R. A.; Simopoulou, E.; Talebzadeh, M.; Vallee, C.; Varvell, K.; Vayaki, A.; Venus, W.; Wells, J.; Wernhard, K. L.; Wittek, W.; Zevgolatakos, E.; WA59 Collaboration

1984-05-01

First observation is reported of semi-inclusive coherent diffractive charged current interactions of antineutrinos on neon nuclei. A sharp peaking towards zero is observed in the | t| distribution of interactions for which the final state charge is 0 and from which only one negative hadron is emitted, unaccompanied by any evidence of nuclear fragmentation or reinteraction. This peak is correlated with high momentum of the outgoing charged hadron and with small values of Q2 and x.

Global and Local Evaluations of Public Speaking Performance in Social Anxiety

PubMed Central

Cody, Meghan W.; Teachman, Bethany A.

2012-01-01

Differences in the relative use of global and local information (seeing the forest versus the trees) may explain why people with social anxiety often do not benefit from corrective feedback, even though they pay close attention to details in social situations. In the current study, participants high (n = 43) or low (n = 47) in social anxiety symptoms gave a series of brief speeches, and then self-rated their speaking performance on items reflecting global and local performance indicators (self assessment) and also received standardized performance feedback from an experimenter. Participants then completed a questionnaire asking how they thought the experimenter would rate their performance based on the feedback provided (experimenter assessment). Participants completed the self and experimenter assessments again after three days, in addition to a measure of post-event processing (repetitive negative thinking) about their speech performance. Results showed that, as hypothesized, the high social anxiety group rated their performance more negatively than the low social anxiety group did. Moreover, the high social anxiety group’s ratings of global aspects of their performance became relatively more negative over time, compared to their ratings of local aspects and the low social anxiety group’s ratings. As expected, post-event processing mediated the relationship between social anxiety group status and worsening global performance evaluations. These findings point to a pattern of progressively more negative global evaluations over time for persons high in social anxiety. PMID:22035989

Social Anxiety and Heavy Situational Drinking: Coping and Conformity Motives as Multiple Mediators

PubMed Central

Terlecki, Meredith A.; Buckner, Julia D.

2014-01-01

Individuals with clinically elevated social anxiety are at greater risk for alcohol use disorder, and the relation between social anxiety and drinking problems is at least partially accounted for by drinking more in negative emotional (e.g., feeling sad or angry) and personal/intimate (e.g., before sexual intercourse) situations. Identification of cognitive/motivational factors related to drinking in these high-risk situations could inform the development of treatment and prevention interventions for these high-risk drinkers. The current study examined the mediating effect of drinking motives on the relationship between social anxiety and drinking these high-risk situations amongst undergraduates (N = 232). Clinically elevated social anxiety was associated with greater coping and conformity motives. Both coping and conformity motives mediated the relation between social anxiety and heavier alcohol consumption in negative emotional and personal/intimate contexts. Multiple mediation analyses indicated that these motives work additively to mediate the social anxiety-drinking situations relationship, such that that heavy situational drinking amongst undergraduates with clinically elevated social anxiety can be jointly attributed to desire to cope with negative affect and to avoid social scrutiny. PMID:25233446

Personality predispositions to depression in children of affectively-ill parents: the buffering role of self-esteem.

PubMed

Abela, John R Z; Fishman, Michael B; Cohen, Joseph R; Young, Jami F

2012-01-01

A major theory of personality predispositions to depression posits that individuals who possess high levels of self-criticism and/or dependency are vulnerable to developing depression following negative life events. The goal of the current study was to test this theory of personality predispositions and the self-esteem buffering hypothesis in a sample of youth using an idiographic approach, a high-risk sample, and a multiwave longitudinal design. One hundred forty children aged 6 to 14 completed measures of dependency, self-criticism, self-esteem, and depressive symptoms. Over the course of the following year, 8 follow-up assessments were conducted 6 weeks apart during which all children were administered measures assessing depressive symptoms and the occurrence of negative events. Results of hierarchical linear modeling analyses indicated that higher levels of dependency were associated with greater increases in depressive symptoms following negative events among children possessing low, but not high, self-esteem. In contrast, self-criticism was not associated with changes in depressive symptoms over time regardless of children's levels of stress and/or self-esteem.

Characteristics of EMI generated by negative metal-positive dielectric voltage stresses due to spacecraft charging

NASA Technical Reports Server (NTRS)

Chaky, R. C.; Inouye, G. T.

1985-01-01

Charging of spacecraft surfaces by the environmental plasma can result in differential potentials between metallic structure and adjacent dielectric surfaces in which the relative polarity of the voltage stress is either negative dielectric/positive metal or negative metal/positive dielectric. Negative metal/positive dielectric is a stress condition that may arise if relatively large areas of spacecraft surface metals are shadowed from solar UV and/or if the UV intensity is reduced as in the situation in which the spacecraft is entering into or leaving eclipse. The results of experimental studies of negative metal/positive dielectric systems are given. Information is given on: enhanced electron emission I-V curves; e(3) corona noise vs e(3) steady-state current; the localized nature of e(3) and negative metal arc discharge currents; negative metal arc discharges at stress thresholds below 1 kilovolt; negative metal arc discharge characteristics; dependence of blowoff arc discharge current on spacecraft capacitance to space (linear dimension); and damage to second surface mirrors due to negative metal arcs.

HIGH VOLTAGE ELECTRODES

DOEpatents

Murray, J.J.

1963-04-23

S>This patent relates to electrode structure for creating an intense direct current electric field which may have a field strength of the order of two to three times that heretofore obtained, with automatic suppression of arcing. The positive electrode is a conventional conductive material such as copper while the negative electrode is made from a special material having a resistivity greater than that of good conductors and less than that of good insulators. When an incipient arc occurs, the moderate resistivity of the negative electrode causes a momentary, localized decrease in the electric field intensity, thus suppressing the flow of electrons and avoiding arcing. Heated glass may be utilized for the negative electrode, since it provides the desired combination of resistivity, capacity, dielectric strength, mechani-cal strength, and thermal stability. (AEC)

High efficiency FET microwave detector design

NASA Astrophysics Data System (ADS)

Luglio, Juan; Ishii, Thomas Koryu

1990-12-01

The work is based on an assumption that very little microwave power would be consumed at a negatively biased gate of a microwave FET, yet significant detected signals would be obtained at the drain if the bias is given. By analyzing a Taylor-series expansion of the drain-current equation in the vicinity of a fixed gate-bias voltage, the bias voltage is found to maximize the second derivative of the drain current, the gate-bias voltage characteristic curve for the maximum detected drain current under a given fixed drain-bias voltage. Based on these findings, a high-efficiency microwave detector is designed, fabricated, and tested at 8.6 GHz, and it is shown that the audio power over absorbed microwave power ratio of the detector is 135 percent due to the positive gain.

Biofunctionalized Zinc Oxide Field Effect Transistors for Selective Sensing of Riboflavin with Current Modulation

PubMed Central

Hagen, Joshua A.; Kim, Sang N.; Bayraktaroglu, Burhan; Leedy, Kevin; Chávez, Jorge L.; Kelley-Loughnane, Nancy; Naik, Rajesh R.; Stone, Morley O.

2011-01-01

Zinc oxide field effect transistors (ZnO-FET), covalently functionalized with single stranded DNA aptamers, provide a highly selective platform for label-free small molecule sensing. The nanostructured surface morphology of ZnO provides high sensitivity and room temperature deposition allows for a wide array of substrate types. Herein we demonstrate the selective detection of riboflavin down to the pM level in aqueous solution using the negative electrical current response of the ZnO-FET by covalently attaching a riboflavin binding aptamer to the surface. The response of the biofunctionalized ZnO-FET was tuned by attaching a redox tag (ferrocene) to the 3′ terminus of the aptamer, resulting in positive current modulation upon exposure to riboflavin down to pM levels. PMID:22163977

431 kA/cm2 peak tunneling current density in GaN/AlN resonant tunneling diodes

NASA Astrophysics Data System (ADS)

Growden, Tyler A.; Zhang, Weidong; Brown, Elliott R.; Storm, David F.; Hansen, Katurah; Fakhimi, Parastou; Meyer, David J.; Berger, Paul R.

2018-01-01

We report on the design and fabrication of high current density GaN/AlN double barrier resonant tunneling diodes grown via plasma assisted molecular-beam epitaxy on bulk GaN substrates. A quantum-transport solver was used to model and optimize designs with high levels of doping and ultra-thin AlN barriers. The devices displayed repeatable room temperature negative differential resistance with peak-to-valley current ratios ranging from 1.20 to 1.60. A maximum peak tunneling current density (Jp) of 431 kA/cm2 was observed. Cross-gap near-UV (370-385 nm) electroluminescence (EL) was observed above +6 V when holes, generated from a polarization induced Zener tunneling effect, recombine with electrons in the emitter region. Analysis of temperature dependent measurements, thermal resistance, and the measured EL spectra revealed the presence of severe self-heating effects.

How does "not left" become "right"? Electrophysiological evidence for a dynamic conflict-bound negation processing account.

PubMed

Dudschig, Carolin; Kaup, Barbara

2018-05-01

Human thought and language is traditionally considered as abstract, amodal, and symbolic. However, recent theories propose that high-level human cognition is directly linked to basic, modal biological systems such as sensorimotor areas. Despite this influential representational debate very little is known regarding whether the mechanisms involved in sensorimotor control are also shared with higher-level cognitive processes, such as language comprehension. We investigated negation as a universal of human language, addressing two key questions: (a) Does negation result in a conflict-like representation? (b) Does negation trigger executive control adjustments in a similar manner as standard information processing conflicts do (e.g., Simon, Flanker)? Electrophysiological data indicated that phrases such as "not left/not right" result in initial activation of the to-be-negated information and subsequently the outcome of the negation process. More importantly, our findings also suggest that negation triggers conflict-related adjustments in information processing in line with traditional conflict tasks. Trial-by-trial conflict adaptation patterns in both behavioral and electrophysiological data indicated that negation processing dynamically changes depending on the current cognitive state. In summary, negation processing results in cognitive conflict, and dynamic influences of the cognitive state determine conflict resolution, that is, negation implementation. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

A Facile Strategy for the Preparation of MoS3 and its Application as a Negative Electrode for Supercapacitors.

PubMed

Zhang, Tong; Kong, Ling-Bin; Dai, Yan-Hua; Yan, Kun; Shi, Ming; Liu, Mao-Cheng; Luo, Yong-Chun; Kang, Long

2016-09-06

Owing to their graphene-like structure and available oxidation valence states, transition metal sulfides are promising candidates for supercapacitors. Herein, we report the application of MoS3 as a new negative electrode for supercapacitors. MoS3 was fabricated by the facile thermal decomposition of a (NH4 )2 MoS4 precursor. For comparison, samples of MoS3 &MoS2 and MoS2 were also synthesized by using the same method. Moreover, this is the first report of the application of MoS3 as a negative electrode for supercapacitors. MoS3 displayed a high specific capacitance of 455.6 F g(-1) at a current density of 0.5 A g(-1) . The capacitance retention of the MoS3 electrode was 92 % after 1500 cycles, and even 71 % after 5000 cycles. In addition, an asymmetric supercapacitor assembly of MoS3 as the negative electrode demonstrated a high energy density at a high potential of 2.0 V in aqueous electrolyte. These notable results show that MoS3 has significant potential in energy-storage devices. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electronegative plasma diagnostic by laser photo-detachment combined with negatively biased Langmuir probe

NASA Astrophysics Data System (ADS)

Oudini, N.; Sirse, N.; Taccogna, F.; Ellingboe, A. R.; Bendib, A.

2018-05-01

We propose a new technique for diagnosing negative ion properties using Langmuir probe assisted pulsed laser photo-detachment. While the classical technique uses a laser pulse to convert negative ions into electron-atom pairs and a positively biased Langmuir probe tracking the change of electron saturation current, the proposed method uses a negatively biased Langmuir probe to track the temporal evolution of positive ion current. The negative bias aims to avoid the parasitic electron current inherent to probe tip surface ablation. In this work, we show through analytical and numerical approaches that, by knowing electron temperature and performing photo-detachment at two different laser wavelengths, it is possible to deduce plasma electronegativity (ratio of negative ion to electron densities) α, and anisothermicity (ratio of electron to negative ion temperatures) γ-. We present an analytical model that links the change in the collected positive ion current to plasma electronegativity and anisothermicity. Particle-In-Cell simulation is used as a numerical experiment covering a wide range of α and γ- to test the new analysis technique. The new technique is sensitive to α in the range 0.5 < α < 10 and yields γ- for large α, where negative ion flux affects the probe sheath behavior, typically α > 1.

Electrostatic energy analyzer measurements of low energy zirconium beam parameters in a plasma sputter-type negative ion source

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

Malapit, Giovanni M.; Department of Physical Sciences, University of the Philippines Baguio, Baguio City 2600; Mahinay, Christian Lorenz S.

2012-02-15

A plasma sputter-type negative ion source is utilized to produce and detect negative Zr ions with energies between 150 and 450 eV via a retarding potential-type electrostatic energy analyzer. Traditional and modified semi-cylindrical Faraday cups (FC) inside the analyzer are employed to sample negative Zr ions and measure corresponding ion currents. The traditional FC registered indistinct ion current readings which are attributed to backscattering of ions and secondary electron emissions. The modified Faraday cup with biased repeller guard ring, cut out these signal distortions leaving only ringings as issues which are theoretically compensated by fitting a sigmoidal function into themore » data. The mean energy and energy spread are calculated using the ion current versus retarding potential data while the beam width values are determined from the data of the transverse measurement of ion current. The most energetic negative Zr ions yield tighter energy spread at 4.11 eV compared to the least energetic negative Zr ions at 4.79 eV. The smallest calculated beam width is 1.04 cm for the negative Zr ions with the highest mean energy indicating a more focused beam in contrast to the less energetic negative Zr ions due to space charge forces.« less

Feeling Bad and Looking Worse: Negative Affect Is Associated with Reduced Perceptions of Face-Healthiness

PubMed Central

Mirams, Laura; Poliakoff, Ellen; Zandstra, Elizabeth H.; Hoeksma, Marco; Thomas, Anna; El-Deredy, Wael

2014-01-01

Some people perceive themselves to look more, or less attractive than they are in reality. We investigated the role of emotions in enhancement and derogation effects; specifically, whether the propensity to experience positive and negative emotions affects how healthy we perceive our own face to look and how we judge ourselves against others. A psychophysical method was used to measure healthiness of self-image and social comparisons of healthiness. Participants who self-reported high positive (N = 20) or negative affectivity (N = 20) judged themselves against healthy (red-tinged) and unhealthy looking (green-tinged) versions of their own and stranger’s faces. An adaptive staircase procedure was used to measure perceptual thresholds. Participants high in positive affectivity were un-biased in their face health judgement. Participants high in negative affectivity on the other hand, judged themselves as equivalent to less healthy looking versions of their own face and a stranger’s face. Affective traits modulated self-image and social comparisons of healthiness. Face health judgement was also related to physical symptom perception and self-esteem; high physical symptom reports were associated a less healthy self-image and high self-reported (but not implicit) self-esteem was associated with more favourable social comparisons of healthiness. Subject to further validation, our novel face health judgement task could have utility as a perceptual measure of well-being. We are currently investigating whether face health judgement is sensitive to laboratory manipulations of mood. PMID:25259802

Neuroticism modulates the effects of intranasal vasopressin treatment on the neural response to positive and negative social interactions.

PubMed

Feng, Chunliang; DeMarco, Ashley C; Haroon, Ebrahim; Rilling, James K

2015-07-01

Neuroticism is a fundamental personality trait associated with proneness to feel negative affect. Here we ask how Neuroticism influences the neural response to positive and negative social interactions and how Neuroticism modulates the effect of intranasal oxytocin (OT) and vasopressin (AVP) on the neural response to social interactions. In a double-blind, placebo-controlled study, 153 male participants were randomized to receive 24 IU intranasal OT, 20 IU AVP or placebo. Afterwards, they were imaged with fMRI while playing an iterated Prisoner's Dilemma Game. On a different day, subjects completed the NEO personality inventory to measure Neuroticism. Neuroticism was positively correlated with the neural response to negative social interactions in the anterior cingulate cortex/medial prefrontal cortex and with the neural response to positive social interactions in the insula, indicating that Neuroticism modulates neuropsychological processing of both negative and positive social interactions. Neuroticism did not modulate the effect of intranasal OT treatment on the neural response to either positive or negative social interactions. On the other hand, AVP treatment significantly interacted with Neuroticism to modulate the BOLD response to both positive and negative social interactions. Specifically, AVP increased anterior cingulate cortex/medial prefrontal cortex and lateral temporal lobe responses to negative social interactions to a greater extent in participants scoring high rather than low on Neuroticism. AVP also increased the insula response to positive social interactions to a greater extent in participants scoring high rather than low on Neuroticism. These results imply that AVP may increase emotion regulation in response to negative social interactions and the salience of positive social interactions to a greater extent in individuals high compared to low in Neuroticism. The current findings urge caution against uniform clinical application of nonapeptides and suggest that their efficacy may vary as a function of personality. Copyright © 2015 Elsevier Ltd. All rights reserved.

Multidimensional Perfectionism and Internalizing Problems: Do Teacher and Classmate Support Matter?

ERIC Educational Resources Information Center

Fredrick, Stephanie Secord; Demaray, Michelle Kilpatrick; Jenkins, Lyndsay N.

2017-01-01

Adolescent stressors coupled with environmental demands, such as pressures to achieve, might lead to negative outcomes for some students. Students who worry about their ability to meet high standards might be more at risk of internalizing problems. The current study investigated the relations among perfectionism, social support, and internalizing…

Strengths-Based Programming for First Nations Youth in Schools: Building Engagement through Healthy Relationships and Leadership Skills

ERIC Educational Resources Information Center

Crooks, Claire V.; Chiodo, Debbie; Thomas, Darren; Hughes, Ray

2010-01-01

First Nations youth in Canada demonstrate disproportionately high rates of negative behaviors such as violence, substance abuse, and leaving school early. An understanding of historical context and current environment helps explain these patterns. Providing culturally relevant opportunities for youth to build healthy relationships and leadership…

75 FR 28619 - Meeting of the Advisory Committee on Blood Safety and Availability

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-21

... began prior to the availability of tests for HIV in early 1985. The deferral has existed in its current form since September 1985. This and other related FDA policies are designed to address the major... screened using highly sensitive tests, screening tests can be falsely negative during the ``window period...

Non-thermal plasma instabilities induced by deformation of the electron energy distribution function

NASA Astrophysics Data System (ADS)

Dyatko, N. A.; Kochetov, I. V.; Napartovich, A. P.

2014-08-01

Non-thermal plasma is a key component in gas lasers, microelectronics, medical applications, waste gas cleaners, ozone generators, plasma igniters, flame holders, flow control in high-speed aerodynamics and others. A specific feature of non-thermal plasma is its high sensitivity to variations in governing parameters (gas composition, pressure, pulse duration, E/N parameter). This sensitivity is due to complex deformations of the electron energy distribution function (EEDF) shape induced by variations in electric field strength, electron and ion number densities and gas excitation degree. Particular attention in this article is paid to mechanisms of instabilities based on non-linearity of plasma properties for specific conditions: gas composition, steady-state and decaying plasma produced by the electron beam, or by an electric current pulse. The following effects are analyzed: the negative differential electron conductivity; the absolute negative electron mobility; the stepwise changes of plasma properties induced by the EEDF bi-stability; thermo-current instability and the constriction of the glow discharge column in rare gases. Some of these effects were observed experimentally and some of them were theoretically predicted and still wait for experimental confirmation.

Plasma bullet current measurements in a free-stream helium capillary jet

NASA Astrophysics Data System (ADS)

Oh, Jun-Seok; Walsh, James L.; Bradley, James W.

2012-06-01

A commercial current monitor has been used to measure the current associated with plasma bullets created in both the positive and negative half cycles of the sinusoidal driving voltage sustaining a plasma jet. The maximum values of the positive bullet current are typically ˜750 µA and persist for 10 µs, while the peaks in the negative current of several hundred μA are broad, persisting for about 40 µs. From the time delay of the current peaks with increasing distance from the jet nozzle, an average bullet propagation speed has been measured; the positive and negative bullets travel at 17.5 km s-1 and 3.9 km s-1 respectively. The net space charge associated with the bullet(s) has also been calculated; the positive and negative bullets contain a similar net charge of the order of 10-9 C measured at all monitor positions, with estimated charged particle densities nb of ˜1010-1011 cm-3 in the bullet.

Interpretation bias for uncertain threat: A replication and extension.

PubMed

Oglesby, Mary E; Raines, Amanda M; Short, Nicole A; Capron, Daniel W; Schmidt, Norman B

2016-06-01

Intolerance of uncertainty (IU) has been proposed as an important transdiagnostic variable within various anxiety-related disorders. Research has suggested that individuals high in IU may interpret ambiguous information in a more threatening manner, suggesting a negative interpretation bias for uncertain information. However, interpretation biases within IU have not been adequately tested in the literature. The current study evaluated negative interpretation biases for uncertain information by directly measuring an individual's interpretations of ambiguous information across two samples. Participants consisted of 76 (Study 1; 72.4% female) and 31 (Study 2; 81% female) undergraduate students. Results indicated that individuals high in IU interpret ambiguous scenarios as more threatening compared to negative and/or positive scenarios (β = .45, p = .02). In addition, individuals high in IU showed a negative interpretation bias for ambiguous information, but not benign information (Study 1: β = -.40, p < .001; Study 2: β = -.57, p = .002). Future research should attempt to replicate these findings within clinical populations. In addition, future work would benefit from the inclusion of behavioral assessments of IU. These findings are the first to detect the presence of a negative interpretation bias for uncertain information among individuals high in IU utilizing a task designed to directly measure an individual's interpretation of information. Given the efficacy and low economic burden associated with interpretation bias modification protocols, and the transdiagnostic nature of IU, targeting IU within these protocols could have a tremendous public health impact. Copyright © 2015 Elsevier Ltd. All rights reserved.

Positive and negative evaluation of relationships: Development and validation of the Positive-Negative Relationship Quality (PN-RQ) scale.

PubMed

Rogge, Ronald D; Fincham, Frank D; Crasta, Dev; Maniaci, Michael R

2017-08-01

Three studies were undertaken to develop the Positive-Negative Relationship Quality scale (PN-RQ), conceptualizing relationship quality as a bidimensional construct in which the positive qualities of a relationship are treated as distinct from its negative qualities. Analyses in emerging adults (Study 1: N = 1,814), in online respondents (Study 2: N = 787) with a 2-week follow-up, and in a single group pre-intervention-post-intervention study (Study 3: N = 54) of the Promoting Awareness, Improving Relationships (PAIR) program provided support for (a) positive and negative qualities as distinct dimensions via confirmatory factor analysis (CFA), (b) the PN-RQ representing an item response theory-optimized measure of these 2 dimensions, (c) substantive differences between indifferent (low positive and negative qualities) and ambivalent (high positive and negative qualities) relationships potentially obscured by unidimensional scales, (d) high levels of responsiveness of the PN-RQ scales to change over time, (e) the unique predictive validity offered over time by the PN-RQ scores beyond that offered by scores of current unidimensional measures of relationship quality, and (f) the unique longitudinal information gained by using the PN-RQ as a bidimensional outcome measure in an intervention study. Taken together, the studies offer promising support for the PN-RQ scales suggesting that they have the potential to advance both basic and applied research. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

The association between ruminative thinking and negative interpretation bias in social anxiety.

PubMed

Badra, Marcel; Schulze, Lars; Becker, Eni S; Vrijsen, Janna Nonja; Renneberg, Babette; Zetsche, Ulrike

2017-09-01

Cognitive models propose that both, negative interpretations of ambiguous social situations and ruminative thoughts about social events contribute to the maintenance of social anxiety disorder. It has further been postulated that ruminative thoughts fuel biased negative interpretations, however, evidence is rare. The present study used a multi-method approach to assess ruminative processing following a social interaction (post-event processing by self-report questionnaire and social rumination by experience sampling method) and negative interpretation bias (via two separate tasks) in a student sample (n = 51) screened for high (HSA) and low social anxiety (LSA). Results support the hypothesis that group differences in negative interpretations of ambiguous social situations in HSAs vs. LSAs are mediated by higher levels of post-event processing assessed in the questionnaire. Exploratory analyses highlight the potential role of comorbid depressive symptoms. The current findings help to advance the understanding of the association between two cognitive processes involved in social anxiety and stress the importance of ruminative post-event processing.

The Costs of Suppressing Negative Emotions and Amplifying Positive Emotions During Parental Caregiving.

PubMed

Le, Bonnie M; Impett, Emily A

2016-03-01

How do parents feel when they regulate their emotional expressions in ways that are incongruent with their genuine feelings? In an experimental study, parents reported experiencing lower authenticity, emotional well-being, relationship quality, and responsiveness to their children's needs when they recalled caregiving experiences in which they suppressed negative emotions and amplified positive emotions, relative to a control condition. In a 10-day daily experience study, parents tended to use both regulation strategies simultaneously. In addition, assessing their unique effects indicated that positive emotion amplification, but not negative emotion suppression, had an indirect effect on parental outcomes via authenticity, with negative emotion suppression no longer being costly. This indirect effect was dampened when accounting for care difficulty. In both studies, effects were independent of a child's mood. The current results suggest that parents' attempts to suppress negative and amplify positive emotions during child care can detract from their well-being and high-quality parent-child bonds. © 2016 by the Society for Personality and Social Psychology, Inc.

Relationship between Counseling Students' Childhood Memories and Current Negative Self-Evaluations When Receiving Corrective Feedback

ERIC Educational Resources Information Center

Stroud, Daniel; Olguin, David; Marley, Scott

2016-01-01

This article entails a study focused on the relationship between counseling students' negative childhood memories of receiving corrective feedback and current negative self-evaluations when receiving similar feedback in counselor education programs. Participants (N = 186) completed the Corrective Feedback Instrument-Revised (CFI-R; Hulse-Killacky…

Prefrontal Transcranial Direct Current Stimulation for Treatment of Schizophrenia With Predominant Negative Symptoms: A Double-Blind, Sham-Controlled Proof-of-Concept Study

PubMed Central

Palm, Ulrich; Keeser, Daniel; Hasan, Alkomiet; Kupka, Michael J.; Blautzik, Janusch; Sarubin, Nina; Kaymakanova, Filipa; Unger, Ina; Falkai, Peter; Meindl, Thomas; Ertl-Wagner, Birgit; Padberg, Frank

2016-01-01

Negative symptoms are highly relevant in the long-term course of schizophrenia and are an important target domain for the development of novel interventions. Recently, transcranial direct current stimulation (tDCS) of the prefrontal cortex has been investigated as a treatment option in schizophrenia. In this proof-of-concept study, 20 schizophrenia patients with predominantly negative symptoms were randomized to either 10 sessions of add-on active (2 mA, 20min) or sham tDCS (anode: left DLPFC/F3; cathode: right supraorbital/F4). Primary outcome measure was the change in the Scale for the Assessment of Negative Symptoms (SANS) sum score; secondary outcomes included reduction in Positive and Negative Syndrome Scale (PANSS) scores and improvement of depressive symptoms, cognitive processing speed, and executive functioning. Sixteen patients underwent 4 functional connectivity magnetic resonance imaging (fcMRI) scans (pre and post 1st and pre and post 10th tDCS) to investigate changes in resting state network connectivity after tDCS. Per-protocol analysis showed a significantly greater decrease in SANS score after active (−36.1%) than after sham tDCS (−0.7%). PANSS sum scores decreased significantly more with active (−23.4%) than with sham stimulation (−2.2%). Explorative analysis of fcMRI data indicated changes in subgenual cortex and dorsolateral prefrontal cortex (DLPFC) connectivity within frontal-thalamic-temporo-parietal networks. The results of this first proof-of-concept study indicate that prefrontal tDCS may be a promising intervention for treatment of schizophrenia with predominant negative symptoms. Large-scale randomized controlled studies are needed to further establish prefrontal tDCS as novel treatment for negative symptoms in schizophrenia. PMID:27098066

Individual and combined effects of multiple high-risk triggers on postcessation smoking urge and lapse.

PubMed

Lam, Cho Y; Businelle, Michael S; Aigner, Carrie J; McClure, Jennifer B; Cofta-Woerpel, Ludmila; Cinciripini, Paul M; Wetter, David W

2014-05-01

Negative affect, alcohol consumption, and presence of others smoking have consistently been implicated as risk factors for smoking lapse and relapse. What is not known, however, is how these factors work together to affect smoking outcomes. This paper uses ecological momentary assessment (EMA) collected during the first 7 days of a smoking cessation attempt to test the individual and combined effects of high-risk triggers on smoking urge and lapse. Participants were 300 female smokers who enrolled in a study that tested an individually tailored smoking cessation treatment. Participants completed EMA, which recorded negative affect, alcohol consumption, presence of others smoking, smoking urge, and smoking lapse, for 7 days starting on their quit date. Alcohol consumption, presence of others smoking, and negative affect were, independently and in combination, associated with increase in smoking urge and lapse. The results also found that the relationship between presence of others smoking and lapse and the relationship between negative affect and lapse were moderated by smoking urge. The current study found significant individual effects of alcohol consumption, presence of other smoking, and negative affect on smoking urge and lapse. Combing the triggers increased smoking urge and the risk for lapse to varying degrees, and the presence of all 3 triggers resulted in the highest urge and lapse risk.

A comprehensive iterative approach is highly effective in diagnosing individuals who are exome negative.

PubMed

Shashi, Vandana; Schoch, Kelly; Spillmann, Rebecca; Cope, Heidi; Tan, Queenie K-G; Walley, Nicole; Pena, Loren; McConkie-Rosell, Allyn; Jiang, Yong-Hui; Stong, Nicholas; Need, Anna C; Goldstein, David B

2018-06-15

Sixty to seventy-five percent of individuals with rare and undiagnosed phenotypes remain undiagnosed after exome sequencing (ES). With standard ES reanalysis resolving 10-15% of the ES negatives, further approaches are necessary to maximize diagnoses in these individuals. In 38 ES negative patients an individualized genomic-phenotypic approach was employed utilizing (1) phenotyping; (2) reanalyses of FASTQ files, with innovative bioinformatics; (3) targeted molecular testing; (4) genome sequencing (GS); and (5) conferring of clinical diagnoses when pathognomonic clinical findings occurred. Certain and highly likely diagnoses were made in 18/38 (47%) individuals, including identifying two new developmental disorders. The majority of diagnoses (>70%) were due to our bioinformatics, phenotyping, and targeted testing identifying variants that were undetected or not prioritized on prior ES. GS diagnosed 3/18 individuals with structural variants not amenable to ES. Additionally, tentative diagnoses were made in 3 (8%), and in 5 individuals (13%) candidate genes were identified. Overall, diagnoses/potential leads were identified in 26/38 (68%). Our comprehensive approach to ES negatives maximizes the ES and clinical data for both diagnoses and candidate gene identification, without GS in the majority. This iterative approach is cost-effective and is pertinent to the current conundrum of ES negatives.

Deliberate real-time mood regulation in adulthood: the importance of age, fixation and attentional functioning.

PubMed

Noh, Soo Rim; Lohani, Monika; Isaacowitz, Derek M

2011-09-01

While previous research has linked executive attention to emotion regulation, the current study investigated the role of attentional alerting (i.e., efficient use of external warning cues) on younger (N=39) and older (N=44) adults' use of gaze to regulate their mood in real time. Participants viewed highly arousing unpleasant images while reporting their mood and were instructed to deliberately manage how they felt and to minimise the effect of those stimuli on their mood. Fixations toward the most negative areas of the images were recorded with eye tracking. We examined whether looking less at the most negative regions, compared to each individual's own tendency, was a beneficial mood regulatory strategy and how it interacted with age and alerting ability. High alerting older adults, who rely more on external cues to guide their attention, experienced a smaller decline in mood over time by activating a less-negative-looking approach (compared to their own average tendency), effectively looking away from the most negative areas of the images. More negative gaze patterns predicted better mood for younger adults, though this effect decreased over time. Alerting did not moderate gaze-mood links in younger adults. Successful mood regulation may thus depend on particular combinations of age, fixation, and attention.

Deliberate Real-time Mood Regulation in Adulthood: The Importance of Age, Fixation and Attentional Functioning

PubMed Central

Noh, Soo Rim; Lohani, Monika; Isaacowitz, Derek M.

2011-01-01

While previous research has linked executive attention to emotion regulation, the current study investigated the role of attentional alerting (i.e., efficient use of external warning cues) on younger (N = 39) and older (N = 44) adults’ use of gaze to regulate their mood in real time. Participants viewed highly arousing unpleasant images while reporting their mood and were instructed to deliberately manage how they felt and to minimize the effect of those stimuli on their mood. Fixations toward the most negative areas of the images were recorded with eye tracking. We examined whether looking less at the most negative regions, compared to each individual’s own tendency, was a beneficial mood regulatory strategy and how it interacted with age and alerting ability. High alerting older adults, who rely more on external cues to guide their attention, experienced a smaller decline in mood over time by activating a less-negative-looking approach (compared to their own average tendency), effectively looking away from the most negative areas of the images. More negative gaze patterns predicted better mood for younger adults, though this effect decreased over time. Alerting did not moderate gaze-mood links in younger adults. Successful mood regulation may thus depend on particular combinations of age, fixation, and attention. PMID:21432641

Effect of incorporation of nitrogen atoms in Al2O3 gate dielectric of wide-bandgap-semiconductor MOSFET on gate leakage current and negative fixed charge

NASA Astrophysics Data System (ADS)

Kojima, Eiji; Chokawa, Kenta; Shirakawa, Hiroki; Araidai, Masaaki; Hosoi, Takuji; Watanabe, Heiji; Shiraishi, Kenji

2018-06-01

We performed first-principle calculations to investigate the effect of incorporation of N atoms into Al2O3 gate dielectrics. Our calculations show that the defect levels generated by VO in Al2O3 are the origin of the stress-induced gate leakage current and that VOVAl complexes in Al2O3 cause negative fixed charge. We revealed that the incorporation of N atoms into Al2O3 eliminates the VO defect levels, reducing the stress-induced gate leakage current. Moreover, this suppresses the formation of negatively charged VOVAl complexes. Therefore, AlON can reduce both stress-induced gate leakage current and negative fixed charge in wide-bandgap-semiconductor MOSFETs.

Emotional reactivity to incentive downshift as a correlated response to selection of high and low alcohol preferring mice and an influencing factor on ethanol intake.

PubMed

Matson, Liana M; Grahame, Nicholas J

2015-11-01

Losing a job or significant other are examples of incentive loss that result in negative emotional reactions. The occurrence of negative life events is associated with increased drinking (Keyes, Hatzenbuehler, & Hasin, 2011). Further, certain genotypes are more likely to drink alcohol in response to stressful negative life events (Blomeyer et al., 2008; Covault et al., 2007). Shared genetic factors may contribute to alcohol drinking and emotional reactivity, but this relationship is not currently well understood. We used an incentive downshift paradigm to address whether emotional reactivity is elevated in mice predisposed to drink alcohol. We also investigated if ethanol drinking is influenced in High Alcohol Preferring mice that had been exposed to an incentive downshift. Incentive downshift procedures have been widely utilized to model emotional reactivity, and involve shifting a high reward group to a low reward and comparing the shifted group to a consistently rewarded control group. Here, we show that replicate lines of selectively bred High Alcohol Preferring mice exhibited larger successive negative contrast effects than their corresponding replicate Low Alcohol Preferring lines, providing strong evidence for a genetic association between alcohol drinking and susceptibility to the emotional effects of negative contrast. These mice can be used to study the shared neurological and genetic underpinnings of emotional reactivity and alcohol preference. Unexpectedly, an incentive downshift suppressed ethanol drinking immediately following an incentive downshift. This could be due to a specific effect of negative contrast on ethanol consumption or a suppressive effect on consummatory behavior in general. These data suggest that either alcohol intake does not provide the anticipated negative reinforcement, or that a single test was insufficient for animals to learn to drink following incentive downshift. However, the emotional intensity following incentive downshift provides initial evidence that this type of emotional reactivity may be a predisposing factor in alcoholism. Copyright © 2015 Elsevier Inc. All rights reserved.

Deficits in Positive Reinforcement Learning and Uncertainty-Driven Exploration are Associated with Distinct Aspects of Negative Symptoms in Schizophrenia

PubMed Central

Strauss, Gregory P.; Frank, Michael J.; Waltz, James A.; Kasanova, Zuzana; Herbener, Ellen S.; Gold, James M.

2011-01-01

Background Negative symptoms are core features of schizophrenia; however, the cognitive and neural basis for individual negative symptom domains remains unclear. Converging evidence suggests a role for striatal and prefrontal dopamine in reward learning and the exploration of actions that might produce outcomes that are better than the status quo. The current study examines whether deficits in reinforcement learning and uncertainty-driven exploration predict specific negative symptoms domains. Methods We administered a temporal decision making task, which required trial-by-trial adjustment of reaction time (RT) to maximize reward receipt, to 51 patients with schizophrenia and 39 age-matched healthy controls. Task conditions were designed such that expected value (probability * magnitude) increased (IEV), decreased (DEV), or remained constant (CEV) with increasing response times. Computational analyses were applied to estimate the degree to which trial-by-trial responses are influenced by reinforcement history. Results Individuals with schizophrenia showed impaired Go learning, but intact NoGo learning relative to controls. These effects were pronounced as a function of global measures of negative symptom. Uncertainty-based exploration was substantially reduced in individuals with schizophrenia, and selectively correlated with clinical ratings of anhedonia. Conclusions Schizophrenia patients, particularly those with high negative symptoms, failed to speed RT's to increase positive outcomes and showed reduced tendency to explore when alternative actions could lead to better outcomes than the status quo. Results are interpreted in the context of current computational, genetic, and pharmacological data supporting the roles of striatal and prefrontal dopamine in these processes. PMID:21168124

High-rate nano-crystalline Li 4Ti 5O 12 attached on carbon nano-fibers for hybrid supercapacitors

NASA Astrophysics Data System (ADS)

Naoi, Katsuhiko; Ishimoto, Shuichi; Isobe, Yusaku; Aoyagi, Shintaro

A lithium titanate (Li 4Ti 5O 12)-based electrode which can operate at unusually high current density (300 C) was developed as negative electrode for hybrid capacitors. The high-rate Li 4Ti 5O 12 electrode has a unique nano-structure consisting of unusually small nano-crystalline Li 4Ti 5O 12 (ca. 5-20 nm) grafted onto carbon nano-fiber anchors (nc-Li 4Ti 5O 12/CNF). This nano-structured nc-Li 4Ti 5O 12/CNF composite are prepared by simple sol-gel method under ultra-centrifugal force (65,000 N) followed by instantaneous annealing at 900 °C for 3 min. A model hybrid capacitor cell consisting of a negative nc-Li 4Ti 5O 12/CNF composite electrode and a positive activated carbon electrode showed high energy density of 40 Wh L -1 and high power density of 7.5 kW L -1 comparable to conventional EDLCs.

Relational Anxiety and Sexting.

PubMed

Weisskirch, Robert S; Drouin, Michelle; Delevi, Rakel

2017-01-01

Individuals in pursuit of, or currently in, a romantic relationship typically communicate via technology, extending to sexting with one another. Sexting is commonly understood as the sending and receiving of sexually suggestive or sexually explicit photos, video, or text via cell phone or other technologies. The characteristics that fuel whether one engages in sexting are not well understood. In this study, 459 unmarried, heterosexual undergraduate students (female = 328; male = 131), aged 18 to 25 years, from three universities completed an online questionnaire about their behaviors with technology and romantic relationships. In general, low attachment avoidance and high fear of negative evaluation from the dating partner predicted sending a sexually suggestive photo or video, sending a photo or video in one's underwear or lingerie, and sending a sexually suggestive text. High fear of negative evaluation predicted sending a nude photo or video as well as sending a text message propositioning sex. Low attachment avoidance, greater fear of negative evaluation, and greater social distress when dating were associated with sexting behaviors.

Moderating Effect of Negative Peer Group Climate on the Relation Between Men's Locus of Control and Aggression Toward Intimate Partners.

PubMed

Schmidt, Megan R; Lisco, Claire G; Parrott, Dominic J; Tharp, Andra T

2016-03-01

The present study sought to examine the interactive effects of an external locus of control and interaction in a negative peer group climate on men's perpetration of physical aggression and infliction of injury toward their female intimate partners. Participants were 206 heterosexual males recruited from the metro-Atlanta community who completed self-report measures of external locus of control, involvement in a negative peer group climate, and physical aggression and infliction of injury against intimate partners during the past 12 months. Negative peer group climate was conceptualized as a peer group that displays behavior which may instigate aggressive norms, attitudes, and behaviors. Results indicated that men with an external locus of control were more likely to perpetrate physical aggression toward and inflict injury on their intimate partners if they reported high, but not low, involvement in a negative peer group climate. These results extend current research suggesting external locus of control as a risk factor for intimate partner aggression by highlighting the impact of negative peer groups. Implications and future intervention research are discussed. © The Author(s) 2014.

Relation between lifespan polytrauma typologies and post-trauma mental health.

PubMed

Contractor, Ateka A; Brown, Lily A; Weiss, Nicole H

2018-01-01

Most individuals experience more than one trauma. Hence, it is important to consider the count and types of traumas (polytraumatization) in relation to post-trauma mental health. The current study examined the relation of polytraumatization patterns to PTSD clusters (intrusions, avoidance, negative alterations in cognitions and mood [NACM], and alterations in arousal and reactivity [AAR]), depression, and impulsivity facets (lack of perseverance, lack of premeditation, negative urgency, sensation seeking) using a web-based sample of 346 participants. Age, gender, race, and ethnicity were covariates. Results of latent class analyses indicated a three-class solution: Low Experience, Moderate Experience - Predominent Threat/Indirect PTEs (Moderate Experience), and High Experience - Predominant Interpersonal PTEs (High/Interpersonal). Multinomial logistic regression results indicated that ethnicity and gender were significant covariates in predicting Low versus High/Interpersonal Class, and Moderate Experience versus High/Interpersonal Class membership, respectively. The High/Interpersonal Class had higher scores on most PTSD clusters, depression, and the impulsivity facets of lack of perseverance and negative urgency compared to the other classes. The Low and Moderate Experience Classes differed on PTSD's avoidance and AAR clusters (lower in the former). Individuals exposed to multiple PTE types, particularly interpersonal traumas, may be at risk for more severe post-trauma symptoms. Copyright © 2017 Elsevier Inc. All rights reserved.

Dissociable neural mechanisms underlying response-based and familiarity-based conflict in working memory.

PubMed

Nelson, James K; Reuter-Lorenz, Patricia A; Sylvester, Ching-Yune C; Jonides, John; Smith, Edward E

2003-09-16

Cognitive control requires the resolution of interference among competing and potentially conflicting representations. Such conflict can emerge at different points between stimulus input and response generation, with the net effect being that of compromising performance. The goal of this article was to dissociate the neural mechanisms underlying different sources of conflict to elucidate the architecture of the neural systems that implement cognitive control. By using functional magnetic resonance imaging and a verbal working memory task (item recognition), we examined brain activity related to two kinds of conflict with comparable behavioral consequences. In a trial of our item-recognition task, participants saw four letters, followed by a retention interval, and a probe letter that did or did not match one of the letters held in working memory (positive probe and negative probe, respectively). On some trials, conflict arose solely because of the current negative probe having a high familiarity, due to its membership in the immediately preceding trial's target set. On other trials, additional conflict arose because of the current negative probe having also been a positive probe on the immediately preceding trial, producing response-level conflict. Consistent with previous work, conflict due to high familiarity was associated with left prefrontal activation, but not with anterior cingulate activation. The response-conflict condition, when compared with high-familiarity conflict trials, was associated with anterior cingulate cortex activation, but with no additional left prefrontal activation. This double dissociation points to differing contributions of specific cortical areas to cognitive control, which are based on the source of conflict.

Deuterium results at the negative ion source test facility ELISE

NASA Astrophysics Data System (ADS)

Kraus, W.; Wünderlich, D.; Fantz, U.; Heinemann, B.; Bonomo, F.; Riedl, R.

2018-05-01

The ITER neutral beam system will be equipped with large radio frequency (RF) driven negative ion sources, with a cross section of 0.9 m × 1.9 m, which have to deliver extracted D- ion beams of 57 A at 1 MeV for 1 h. On the extraction from a large ion source experiment test facility, a source of half of this size is being operational since 2013. The goal of this experiment is to demonstrate a high operational reliability and to achieve the extracted current densities and beam properties required for ITER. Technical improvements of the source design and the RF system were necessary to provide reliable operation in steady state with an RF power of up to 300 kW. While in short pulses the required D- current density has almost been reached, the performance in long pulses is determined in particular in Deuterium by inhomogeneous and unstable currents of co-extracted electrons. By application of refined caesium evaporation and distribution procedures, and reduction and symmetrization of the electron currents, considerable progress has been made and up to 190 A/m2 D-, corresponding to 66% of the value required for ITER, have been extracted for 45 min.

Forward Current Transport Mechanisms of Ni/Au—InAlN/AlN/GaN Schottky Diodes

NASA Astrophysics Data System (ADS)

Wang, Xiao-Feng; Shao, Zhen-Guang; Chen, Dun-Jun; Lu, Hai; Zhang, Rong; Zheng, You-Dou

2014-05-01

We fabricate two Ni/Au-In0.17Al0.83N/AlN/GaN Schottky diodes on substrates of sapphire and Si, respectively, and investigate their forward-bias current transport mechanisms by temperature-dependent current-voltage measurements. In the temperature range of 300-485 K, the Schottky barrier heights (SBHs) calculated by using the conventional thermionic-emission (TE) model are strongly positively dependent on temperature, which is in contrast to the negative-temperature-dependent characteristic of traditional semiconductor Schottky diodes. By fitting the forward-bias I-V characteristics using different current transport models, we find that the tunneling current model can describe generally the I-V behaviors in the entire measured range of temperature. Under the high forward bias, the traditional TE mechanism also gives a good fit to the measured I-V data, and the actual barrier heights calculated according to the fitting TE curve are 1.434 and 1.413 eV at 300K for InAlN/AlN/GaN Schottky diodes on Si and the sapphire substrate, respectively, and the barrier height shows a slightly negative temperature coefficient. In addition, a formula is given to estimate SBHs of Ni/Au—InAlN/AlN/GaN Schottky diodes taking the Fermi-level pinning effect into account.

How Self-Generated Thought Shapes Mood—The Relation between Mind-Wandering and Mood Depends on the Socio-Temporal Content of Thoughts

PubMed Central

Ruby, Florence J. M.; Smallwood, Jonathan; Engen, Haakon; Singer, Tania

2013-01-01

Recent work has highlighted that the generation of thoughts unrelated to the current environment may be both a cause and a consequence of unhappiness. The current study used lag analysis to examine whether the relationship between self-generated thought and negative affect depends on the content of the thoughts themselves. We found that the emotional content could strongly predict subsequent mood (e.g. negative thoughts were associated with subsequent negative mood). However, this direct relationship was modulated by the socio-temporal content of the thoughts: thoughts that were past- and other-related were associated with subsequent negative mood, even if current thought content was positive. By contrast, future- and self-related thoughts preceded improvements of mood, even when current thought content was negative. These results highlight the important link between self-generated thought and mood and suggest that the socio-temporal content plays an important role in determining whether an individual's future affective state will be happy or sad. PMID:24194889

Novel technique to ensure battery reliability in 42-V PowerNets for new-generation automobiles

NASA Astrophysics Data System (ADS)

Lam, L. T.; Haigh, N. P.; Phyland, C. G.; Huynh, T. D.

The proposed 42-V PowerNet in automobiles requires the battery to provide a large number of shallow discharge-charge cycles at a high rate. High-rate discharge is necessary for engine cranking, while high-rate charge is associated with regenerative braking. The battery will therefore operate at these high rates in a partial-state-of-charge condition — 'HRPSoC duty'. Under simulated HRPSoC duty, it is found that the valve-regulated lead-acid (VRLA) battery fails prematurely due to the progressive accumulation of lead sulfate mainly on the surfaces of the negative plates. This is because the lead sulfate layer cannot be converted efficiently back to sponge lead during charging either from the engine or from the regenerative braking. Eventually, this layer of lead sulfate develops to such extent that the effective surface area of the plate is reduced markedly and the plate can no longer deliver the high-cranking current demanded by the automobile. The objective of this study is to develop and optimize a pulse-generation technique to minimize the development of lead sulfate layers on negative plates of VRLA batteries subjected to HRPSoC duty. The technique involves the application of sets of charging pulses of different frequency. It is found that the cycle-life performance of VRLA batteries is enhanced markedly when d.c. pulses of high frequency are used. For example, battery durability is raised from ˜10 600 cycles (no pulses) to 32 000 cycles with pulses of high frequency. Two key factors contribute to this improvement. The first factor is localization of the charging current on the surfaces of the plates — the higher the frequency, the greater is the amount of current concentrated on the plate surface. This phenomenon is known as the 'skin effect' as only the outer 'skin' of the plate is effectively carrying the current. The second factor is delivery of sufficient charge to the Faradaic resistance of the plate to compensate for the energy loss to inductance and double-layer capacitance effects. The Faradaic resistance represents the electrochemical reaction, i.e., conversion of lead sulfate to lead. The inductance simply results from the connection either between the cables and the terminals of the battery or between the terminals, bus-bars, and the lugs of the plates. The capacitance arises from the double layer which exists at the interface between the plate and the electrolyte solution. These findings have provided a demonstration and a scientific explanation of the benefit of superimposed pulsed current charging in suppressing the sulfation of negative plates in VRLA batteries operated under 42-V PowerNet and hybrid electric vehicle duties. A Novel Pulse™ device has been developed by the CSIRO. This device has the capability to be programmable to suite various applications and can be miniaturized to be encapsulated in the battery cover.

Improvement of Current Drive Efficiency in Projected FNSF Discharges

NASA Astrophysics Data System (ADS)

Prater, R.; Chan, V.; Garofalo, A.

2012-10-01

The Fusion Nuclear Science Facility - Advanced Tokamak (FNSF-AT) is envisioned as a facility that uses the tokamak approach to address the development of the AT path to fusion and fusion's energy objectives. It uses copper coils for a compact device with high βN and moderate power gain. The major radius is 2.7 m and central toroidal field is 5.44 T. Achieving the required confinement and stability at βN˜3.7 requires a current profile with negative central shear and qmin>1. Off-axis Electron Cyclotron Current Drive (ECCD), in addition to high bootstrap current fraction, can help support this current profile. Using the applied EC frequency and launch location as free parameters, a systematic study has been carried out to optimize the ECCD in the range ρ= 0.5-0.7. Using a top launch, making use of a large toroidal component to the launch direction, adjusting the vertical launch angle so that the rays propagate nearly parallel to the resonance, and adjusting the frequency for optimum total current give a high dimensionless efficiency of 0.44 for a broad ECCD profile peaked at ρ=0.7, and the driven current is 17 kA/MW for n20= 2.1 and Te= 10.3 keV locally.

Development of novel Alicyclobacillus spp. isolation medium.

PubMed

Chang, S; Kang, D-H

2005-01-01

To develop a new isolation medium with higher recovery rates of Alicyclobacillus spp. SK agar was developed with optimized incubation temperature, pH, acidulant, Tween 80 concentration and divalent cation addition. Results indicate that detection of Alicyclobacillus spp. by SK agar was significantly higher (P > 0.05) than those obtained by K agar, orange serum agar, and potato dextrose agar. Current media used for Alicyclobacillus spp. isolation still resulted in high numbers of false negative products. The sensitivity of SK agar to Alicyclobacillus spp. allows detection of low numbers of Alicyclobacillus spp. and also provides a more higher isolation results compared with currently used media. SK agar will be useful to the fruit juice industry to obtain more accurate numbers of contaminant Alicyclobacillus spp. With this media, false negative samples can be reduced, and the likelihood of exported products being rejected can be greatly reduced.

When you see it, let it be: Urgency, mindfulness and adolescent substance use.

PubMed

Robinson, Joanna M; Ladd, Benjamin O; Anderson, Kristen G

2014-06-01

The emotion-based domains of impulsivity, positive and negative urgency, are facets that have garnered attention due to their associations with substance use, and mindfulness based strategies have shown promise in reducing substance use in adults. The aim of the current study was to examine relations among urgency, mindfulness, and substance use in adolescence. Cross-sectional data were collected from students (N=1,051) at a large, private high school in the Pacific Northwest. Both positive and negative urgency were uniquely associated with greater likelihood of lifetime and current alcohol use; only positive urgency predicted lifetime marijuana use. Mindfulness was associated with a lower likelihood of lifetime alcohol or marijuana use. Interactions between urgency and mindfulness were not supported. Our findings highlight the need to explore relations among baseline mindfulness, skills based mindfulness, and personality in adolescent alcohol and other drug use. Copyright © 2014 Elsevier Ltd. All rights reserved.

When you see it, let it be: Urgency, mindfulness and adolescent substance use

PubMed Central

Robinson, Joanna M.; Ladd, Benjamin O.; Anderson, Kristen G.

2015-01-01

The emotion-based domains of impulsivity, positive and negative urgency, are facets that have garnered attention due to their associations with substance use, and mindfulness based strategies have shown promise in reducing substance use in adults. The aim of the current study was to examine relations among urgency, mindfulness, and substance use in adolescence. Cross-sectional data were collected from students (N = 1,051) at a large, private high school in the Pacific Northwest. Both positive and negative urgency were uniquely associated with greater likelihood of lifetime and current alcohol use; only positive urgency predicted lifetime marijuana use. Mindfulness was associated with a lower likelihood of lifetime alcohol or marijuana use. Interactions between urgency and mindfulness were not supported. Our findings highlight the need to explore relations among baseline mindfulness, skills based mindfulness, and personality in adolescent alcohol and other drug use. PMID:24629324

The Food Marketing Defense Model: Integrating Psychological Research to Protect Youth and Inform Public Policy.

PubMed

Harris, Jennifer L; Brownell, Kelly D; Bargh, John A

2009-12-01

Marketing practices that promote calorie-dense, nutrient-poor foods directly to children and adolescents present significant public health risk. Worldwide, calls for government action and industry change to protect young people from the negative effects of food marketing have increased. Current proposals focus on restricting television advertising to children under 12 years old, but current psychological models suggest that much more is required. All forms of marketing pose considerable risk; adolescents are also highly vulnerable; and food marketing may produce far-reaching negative health outcomes. We propose a food marketing defense model that posits four necessary conditions to effectively counter harmful food marketing practices: awareness, understanding, ability and motivation to resist. A new generation of psychological research is needed to examine each of these processes, including the psychological mechanisms through which food marketing affects young people, to identify public policy that will effectively protect them from harmful influence.

The Food Marketing Defense Model: Integrating Psychological Research to Protect Youth and Inform Public Policy

PubMed Central

Harris, Jennifer L.; Brownell, Kelly D.; Bargh, John A.

2009-01-01

Marketing practices that promote calorie-dense, nutrient-poor foods directly to children and adolescents present significant public health risk. Worldwide, calls for government action and industry change to protect young people from the negative effects of food marketing have increased. Current proposals focus on restricting television advertising to children under 12 years old, but current psychological models suggest that much more is required. All forms of marketing pose considerable risk; adolescents are also highly vulnerable; and food marketing may produce far-reaching negative health outcomes. We propose a food marketing defense model that posits four necessary conditions to effectively counter harmful food marketing practices: awareness, understanding, ability and motivation to resist. A new generation of psychological research is needed to examine each of these processes, including the psychological mechanisms through which food marketing affects young people, to identify public policy that will effectively protect them from harmful influence. PMID:20182647

Electric field modulated ferromagnetism in ZnO films deposited at room temperature

NASA Astrophysics Data System (ADS)

Bu, Jianpei; Liu, Xinran; Hao, Yanming; Zhou, Guangjun; Cheng, Bin; Huang, Wei; Xie, Jihao; Zhang, Heng; Qin, Hongwei; Hu, Jifan

2018-04-01

The ZnO film deposited at room temperature, which is composed of the amorphous-phase background plus a few nanograins or nanoclusters (about 1-2 nm), exhibits room temperature ferromagnetism (FM). Such FM is found to be connected with oxygen vacancies. For the Ta/ZnO/Pt device based on the medium layer ZnO deposited at room temperature, the saturation magnetization not only is modulated between high and low resistive states by electric voltage with DC loop electric current but also increases/decreases through adjusting the magnitudes of positive/negative DC sweeping voltage. Meanwhile, the voltage-controlled conductance quantization is observed in Ta/ZnO/Pt, accompanying the voltage-controlled magnetization. However, the saturation magnetization of the Ta/ZnO/Pt device becomes smaller under positive electric voltage and returns in some extent under negative electric voltage, when the DC loop electric current is not applied.

Deducing the Milky Way's Massive Cluster Population

NASA Astrophysics Data System (ADS)

Hanson, M. M.; Popescu, B.; Larsen, S. S.; Ivanov, V. D.

2010-11-01

Recent near-infrared surveys of the galactic plane have been used to identify new massive cluster candidates. Follow up study indicates about half are not true, gravitationally-bound clusters. These false positives are created by high density fields of unassociated stars, often due to a sight-line of reduced extinction. What is not so easy to estimate is the number of false negatives, clusters which exist but are not currently being detected by our surveys. In order to derive critical characteristics of the Milky Way's massive cluster population, such as cluster mass function and cluster lifetimes, one must be able to estimate the characteristics of these false negatives. Our group has taken on the daunting task of attempting such an estimate by first creating the stellar cluster imaging simulation program, MASSCLEAN. I will present our preliminary models and methods for deriving the biases of current searches.

The role of controlled attention on recall in major depression

PubMed Central

Ellis, Alissa J.; Wells, Tony T.; Vanderlind, W. Michael; Beevers, Christopher G.

2013-01-01

Information processing biases are hallmark features of major depressive disorder (MDD). Depressed individuals display biased memory and attention for negative material. Given that memory is highly dependent on attention for initial encoding, understanding the interplay of these processes may provide important insight into mechanisms that produce memory biases in depression. In particular, attentional control—the ability to selectively attend to task-relevant information by both inhibiting the processing of irrelevant information and disengaging attention from irrelevant material—may be one area of impairment in MDD. In the current study, clinically depressed (MDD: n = 15) and never depressed (non- MDD: n = 22) participants’ line of visual gaze was assessed while participants viewed positive and negative word pairs. For each word pair, participants were instructed to attend to one word (target) and ignore one word (distracter). Free recall of study stimuli was then assessed. Depressed individuals displayed greater recall of negatively valenced target words following the task. Although there were no group differences in attentional control in the context of negative words, attention to negative targets mediated the relationship between depression status and recall of negative words. Results suggest a stronger link between attention and memory for negative material in MDD. PMID:24006889

The role of controlled attention on recall in major depression.

PubMed

Ellis, Alissa J; Wells, Tony T; Vanderlind, W Michael; Beevers, Christopher G

2014-04-01

Information processing biases are hallmark features of major depressive disorder (MDD). Depressed individuals display biased memory and attention for negative material. Given that memory is highly dependent on attention for initial encoding, understanding the interplay of these processes may provide important insight into mechanisms that produce memory biases in depression. In particular, attentional control-the ability to selectively attend to task-relevant information by both inhibiting the processing of irrelevant information and disengaging attention from irrelevant material-may be one area of impairment in MDD. In the current study, clinically depressed (MDD: n = 15) and never depressed (non-MDD: n = 22) participants' line of visual gaze was assessed while participants viewed positive and negative word pairs. For each word pair, participants were instructed to attend to one word (target) and ignore one word (distracter). Free recall of study stimuli was then assessed. Depressed individuals displayed greater recall of negatively valenced target words following the task. Although there were no group differences in attentional control in the context of negative words, attention to negative targets mediated the relationship between depression status and recall of negative words. Results suggest a stronger link between attention and memory for negative material in MDD.

Pulsed, high-current, in-line reversal electron attachment detector

NASA Technical Reports Server (NTRS)

Bernius, Mark T.; Chutjian, Ara

1989-01-01

A new, pulsed, high-current, in-line reversal electron attachment ionizer/detector is described. The ionizer is capable of delivering a beam of electrons into an electrostatic mirror field to form a planar wall of electrons having zero kinetic energy. Electron attachment to a molecular target at the reversal point produces either parent or fragment negative ions through a zero-energy (s-wave) state. The atomic or molecular ion is pulsed out of the attachment region approximately 2 microsec after the electrons are pulsed off, and focused onto the entrance plane of a quadrupole mass analyzer. The sensitivity of the apparatus is preliminarily assessed, and its higher-energy behavior with regard to molecular attachment and ionization is described.

Reflex Human Papillomavirus Test Results as an Option for the Management of Korean Women With Atypical Squamous Cells Cannot Exclude High-Grade Squamous Intraepithelial Lesion

PubMed Central

Ryu, Ki-Jin; Lee, Sanghoon; Min, Kyung-Jin; Kim, Jae Won; Hong, Jin Hwa; Song, Jae Yun; Lee, Jae Kwan

2015-01-01

Background. Current guidelines recommend initial colposcopy with biopsy regardless of human papillomavirus (HPV) test results in women with atypical squamous cells, cannot exclude high-grade squamous intraepithelial lesion (ASC-H). The purpose of this study was to evaluate the value of HPV testing in women with ASC-H based on colposcopic pathology results. Materials and Methods. A multicenter cross-sectional study was carried out at three academic hospitals and involved 40,847 Korean women who underwent cervical cancer screening with cytology and HPV tests with or without subsequent colposcopic biopsies between January 2007 and December 2013. Results. ASC-H was diagnosed in 276 women (0.7%). Only 6 of 68 (8.8%) women with ASC-H who were HPV negative had cervical intraepithelial neoplasia grade ≥2 (CIN ≥2) lesions, whereas 47.4% of the women with ASC-H who were HPV positive had CIN ≥2 lesions. No cases of invasive cervical cancer were diagnosed among women with ASC-H who were HPV negative. Logistic regression analysis was performed using the group with normal Papanicolaou test results and HPV-negative status as the reference group. Women with ASC-H who were HPV positive had a significantly increased risk of CIN ≥2 lesions, whereas no significant increase was observed in patients with ASC-H and HPV-negative status. Conclusion. If the result of the HPV test was negative, the risk of CIN ≥2 lesions in Korean women with ASC-H cytology was low. Reflex HPV testing should be an option for the management of women with cytology showing ASC-H to decrease unnecessary colposcopic biopsies, which are expensive and invasive. Implications for Practice: Current American Society for Colposcopy and Cervical Pathology guidelines recommend universal colposcopy for the management of women with atypical squamous cells, cannot exclude high-grade squamous intraepithelial lesion (ASC-H) on cytology, regardless of human papillomavirus (HPV) test results. The present study suggested that HPV cotesting in patients with ASC-H cytology can provide more detailed and useful information regarding the risk of high-grade cervical intraepithelial neoplasia (CIN) lesions and the need for further treatment. When the result of the HPV test was negative, the risk of CIN lesions of grade ≥2 in women with ASC-H cytology was low. Consequently, reflex HPV testing, rather than immediately performance of invasive and expensive colposcopy with biopsy, should be an option for the management of women with ASC-H. PMID:25964305

Reversal electron attachment ionizer for detection of trace species

NASA Technical Reports Server (NTRS)

Bernius, Mark T. (Inventor); Chutjian, Ara (Inventor)

1990-01-01

An in-line reversal electron, high-current ionizer capable of focusing a beam of electrons to a reversal region and executing a reversal of said electrons, such that the electrons possess zero kinetic energy at the point of reversal, may be used to produce both negative and positive ions. A sample gas is introduced at the point of electron reversal for low energy electron-(sample gas) molecule attachment with high efficiency. The attachment process produces negative ions from the sample gas, which includes species present in trace (minute) amounts. These ions are extracted efficiently and directed to a mass analyzer where they may be detected and identified. The generation and detection of positive ions is accomplished in a similar fashion with minimal adjustment to potentials applied to the apparatus.

Reversal electron attachment ionizer for detection of trace species

NASA Technical Reports Server (NTRS)

Bernius, Mark T. (Inventor); Chutjian, Ara (Inventor)

1989-01-01

An in-line reversal electron, high-current ionizer capable of focusing a beam of electrons to a reversal region and executing a reversal of the electrons, such that the electrons possess zero kinetic energy at the point of reversal, may be used to produce both negative and positive ions. A sample gas is introduced at the point of electron reversal for low energy electron-(sample gas) molecule attachment with high efficiency. The attachment process produces negative ions from the sample gas, which includes species present in trace (minute) amounts. These ions are extracted efficiently and directed to a mass analyzer where they may be detected and identified. The generation and detection of positive ions is accomplished in a similar fashion with minimal adjustment to potentials applied to the apparatus.

Cheating, breakup, and divorce: is Facebook use to blame?

PubMed

Clayton, Russell B; Nagurney, Alexander; Smith, Jessica R

2013-10-01

The purpose of the present study was to investigate the relationship between using the social networking site known as Facebook and negative interpersonal relationship outcomes. A survey of 205 Facebook users aged 18-82 was conducted using a 16-question online survey to examine whether high levels of Facebook use predicted negative relationship outcomes (breakup/divorce, emotional cheating, and physical cheating). It was hypothesized that those with higher levels of Facebook use would demonstrate more negative relationship outcomes than those with lower use. The study then examined whether these relationships were mediated by Facebook-related conflict. Furthermore, the researchers examined length of relationship as a moderator variable in the aforementioned model. The results indicate that a high level of Facebook usage is associated with negative relationship outcomes, and that these relationships are indeed mediated by Facebook-related conflict. This series of relationships only holds for those who are, or have been, in relatively newer relationships of 3 years or less. The current study adds to the growing body of literature investigating Internet use and relationship outcomes, and may be a precursor to further research investigating whether Facebook use attributes to the divorce rate, emotional cheating, and physical cheating.

Effects of Gymnastics Activities on Bone Accrual during Growth: A Systematic Review.

PubMed

Jürimäe, Jaak; Gruodyte-Raciene, Rita; Baxter-Jones, Adam D G

2018-06-01

The amount of bone gained during childhood and adolescence impacts greatly on lifetime skeletal health. The purpose of this review is to summarize current evidence of the effects of gymnastics activities on bone mineral accrual during growth and to describe possible factors that influence bone mineral gains. The PubMed and SportDiscus databases were searched, and a total of 24 articles met the selection criteria and were included in this review. Artistic and rhythmic gymnasts presented higher bone mineral density and content values compared to untrained controls, despite possible negative effects associated with hormonal levels, dietary restrictions and body fat. The results suggest that gymnasts had similar bone turnover values compared to untrained controls. High-intensity mechanical loading of gymnastics activity appears to increase bone development and counterbalance negative effects, such as later pubertal development, lower body fat mass and lower hormone levels. In conclusion, gymnasts present higher bone mineral values in comparison with untrained controls. The osteogenic effect of gymnastics athletic activity has a positive influence on bone mineral accrual and overcomes the possible negative influence of high athletic activity that may cause negative energy balance and low body fat mass which are associated with lower bone accrual.

Repetitive transcranial magnetic stimulation modulates the impact of a negative mood induction

PubMed Central

Lacomblé, Lylis; Meyer, Thomas; Schutter, Dennis J.L.G.; Gielkens, Tom; Becker, Eni S.; Tendolkar, Indira; van Eijndhoven, Philip

2017-01-01

Abstract High frequency repetitive Transcranial Magnetic Stimulation (rTMS) over the left dorsolateral prefrontal cortex (DLPFC) has been found to alleviate depressive symptoms. However, the mechanisms driving these effects are still poorly understood. In the current study, we tested the idea that this intervention protects against negative mood shifts following emotional provocation. We furthermore explored changes in EEG activity (frontal alpha asymmetry) and effects on attentional processing (emotional Stroop). To this end, 23 healthy individuals participated in two sessions separated by one week, whereby they once received 15 min of 10Hz rTMS stimulation (1500 pulses) at 110% of the individual motor threshold, and once sham stimulation. Then, negative mood was induced using sad movie clips. The results revealed a significantly stronger mood decline following rTMS compared to sham stimulation. No changes were observed in frontal alpha asymmetry and attentional processing. Our findings are at odds with the view that high frequency rTMS over the left DLPFC directly protects against the induction of negative mood, but rather suggest that it enhances the effects of emotional provocation. Possibly, in healthy young individuals, this stimulation protocol heightens susceptibility to mood induction procedures in general. PMID:28008080

Depressive symptoms, depression proneness, and outcome expectancies for cigarette smoking.

PubMed

Friedman-Wheeler, Dara G; Ahrens, Anthony H; Haaga, David A F; McIntosh, Elizabeth; Thorndike, Frances P

2007-08-01

The high rates of cigarette smoking among depressed persons may be partially explained by increased positive expectancies for cigarette smoking among this population. In view of theoretical and empirical work on depressed people's negative views of the future, though, it would be expected that depressed smokers would hold particularly negative expectancies about the effects of cigarette smoking. The two current studies examined the relations between depression and smoking outcome expectancies in (a) a general population of adult regular smokers and (b) adult smokers seeking to quit smoking. Depressive symptoms and depression proneness both showed significant positive correlations with positive expectancies for cigarette smoking. Several positive correlations with negative expectancies also emerged. Thus, experiencing depressive symptoms may serve to amplify both favorable and unfavorable expectancies about the effects of smoking.

Statistical average estimates of high latitude field-aligned currents from the STARE and SABRE coherent VHF radar systems

NASA Astrophysics Data System (ADS)

Kosch, M. J.; Nielsen, E.

Two bistatic VHF radar systems, STARE and SABRE, have been employed to estimate ionospheric electric fields in the geomagnetic latitude range 61.1 - 69.3° (geographic latitude range 63.8 - 72.6°) over northern Scandinavia. 173 days of good backscatter from all four radars have been analysed during the period 1982 to 1986, from which the average ionospheric divergence electric field versus latitude and time is calculated. The average magnetic field-aligned currents are computed using an AE-dependent empirical model of the ionospheric conductance. Statistical Birkeland current estimates are presented for high and low values of the Kp and AE indices as well as positive and negative orientations of the IMF B z component. The results compare very favourably to other ground-based and satellite measurements.

Design of high-voltage, high-power, solid state remote power controllers for aerospace applications

NASA Technical Reports Server (NTRS)

Sturman, J. C.

1985-01-01

Two general types of remote power controllers (RPC's), which combine the functions of a circuit breaker and a switch, were developed for use in dc aerospace systems. Power-switching devices used in the designs are the gate-turnoff thyristor (GTO) and MOSFET. The RPC's can switch dc voltages to 1200 V and currents to 1000 A. Seven different units were constructed and subjected to laboratory and thermal vacuum testing. Two of these were dual units that switch both positive and negative voltages simultaneously. The RPC's using MOSFET's have slow turnon and turnoff times which limit surge currents and voltage spiking from high di/dt. The GTO's have much faster transition times. All RPC's have programmable overload tripout proportional to I sq T and microsecond tripout for large overloads.

Design of high-voltage, high-power, solid state remote power controllers for aerospace applications

NASA Astrophysics Data System (ADS)

Sturman, J. C.

1985-05-01

Two general types of remote power controllers (RPC's), which combine the functions of a circuit breaker and a switch, were developed for use in dc aerospace systems. Power-switching devices used in the designs are the gate-turnoff thyristor (GTO) and MOSFET. The RPC's can switch dc voltages to 1200 V and currents to 1000 A. Seven different units were constructed and subjected to laboratory and thermal vacuum testing. Two of these were dual units that switch both positive and negative voltages simultaneously. The RPC's using MOSFET's have slow turnon and turnoff times which limit surge currents and voltage spiking from high di/dt. The GTO's have much faster transition times. All RPC's have programmable overload tripout proportional to I sq T and microsecond tripout for large overloads.

Improving Academic Achievement of Students with Problematic Attendance by Implementing a Multisystemic School-Based Model

ERIC Educational Resources Information Center

Kay, James Edward

2010-01-01

This study addressed the problem of poor attendance adversely affecting grades and learning. Current school policies do not address problematic attendance for all school-aged children, perpetuating trends of academic failure. The research objective was to determine if unexcused absences had a greater negative impact on a high-stakes test compared…

Laser-driven relativistic electron dynamics in a cylindrical plasma channel

NASA Astrophysics Data System (ADS)

Geng, Pan-Fei; Lv, Wen-Juan; Li, Xiao-Liang; Tang, Rong-An; Xue, Ju-Kui

2018-03-01

The energy and trajectory of the electron, which is irradiated by a high-power laser pulse in a cylindrical plasma channel with a uniform positive charge and a uniform negative current, have been analyzed in terms of a single-electron model of direct laser acceleration. We find that the energy and trajectory of the electron strongly depend on the positive charge density, the negative current density, and the intensity of the laser pulse. The electron can be accelerated significantly only when the positive charge density, the negative current density, and the intensity of the laser pulse are in suitable ranges due to the dephasing rate between the wave and electron motion. Particularly, when their values satisfy a critical condition, the electron can stay in phase with the laser and gain the largest energy from the laser. With the enhancement of the electron energy, strong modulations of the relativistic factor cause a considerable enhancement of the electron transverse oscillations across the channel, which makes the electron trajectory become essentially three-dimensional, even if it is flat at the early stage of the acceleration. Project supported by the National Natural Science Foundation of China (Grant Nos. 11475027, 11765017, 11764039, 11305132, and 11274255), the Natural Science Foundation of Gansu Province, China (Grant No. 17JR5RA076), and the Scientific Research Project of Gansu Higher Education, China (Grant No. 2016A-005).

Enhanced negative feedback responses in remitted depression.

PubMed

Santesso, Diane L; Steele, Katherine T; Bogdan, Ryan; Holmes, Avram J; Deveney, Christen M; Meites, Tiffany M; Pizzagalli, Diego A

2008-07-02

Major depressive disorder (MDD) is characterized by hypersensitivity to negative feedback that might involve frontocingulate dysfunction. MDD patients exhibit enhanced electrophysiological responses to negative internal (errors) and external (feedback) cues. Whether this dysfunction extends to remitted depressed (RD) individuals with a history of MDD is currently unknown. To address this issue, we examined the feedback-related negativity in RD and control participants using a probabilistic punishment learning task. Despite equivalent behavioral performance, RD participants showed larger feedback-related negativities to negative feedback relative to controls; group differences remained after accounting for residual anxiety and depressive symptoms. The present findings suggest that abnormal responses to negative feedback extend to samples at increased risk for depressive episodes in the absence of current symptoms.

Negative voltage modulated multi-level resistive switching by using a Cr/BaTiOx/TiN structure and quantum conductance through evidence of H2O2 sensing mechanism.

PubMed

Chakrabarti, Somsubhra; Ginnaram, Sreekanth; Jana, Surajit; Wu, Zong-Yi; Singh, Kanishk; Roy, Anisha; Kumar, Pankaj; Maikap, Siddheswar; Qiu, Jian-Tai; Cheng, Hsin-Ming; Tsai, Ling-Na; Chang, Ya-Ling; Mahapatra, Rajat; Yang, Jer-Ren

2017-07-05

Negative voltage modulated multi-level resistive switching with quantum conductance during staircase-type RESET and its transport characteristics in Cr/BaTiO x /TiN structure have been investigated for the first time. The as-deposited amorphous BaTiO x film has been confirmed by high-resolution transmission electron microscopy. X-ray photo-electron spectroscopy shows different oxidation states of Ba in the switching material, which is responsible for tunable more than 10 resistance states by varying negative stop voltage owing to slow decay value of RESET slope (217.39 mV/decade). Quantum conductance phenomenon has been observed in staircase RESET cycle of the memory devices. By inspecting the oxidation states of Ba + and Ba 2+ through measuring H 2 O 2 with a low concentration of 1 nM in electrolyte/BaTiO x /SiO 2 /p-Si structure, the switching mechanism of each HRS level as well as the multi-level phenomenon has been explained by gradual dissolution of oxygen vacancy filament. Along with negative stop voltage modulated multi-level, current compliance dependent multi-level has also been demonstrated and resistance ratio up to 2000 has been achieved even for a thin (<5 nm) switching material. By considering oxidation-reduction of the conducting filaments, the current-voltage switching curve has been simulated as well. Hence, multi-level resistive switching of Cr/BaTiO x /TiN structure implies the promising applications in high dense, multistate non-volatile memories in near future.

Current trends in endotoxin detection and analysis of endotoxin-protein interactions.

PubMed

Dullah, Elvina Clarie; Ongkudon, Clarence M

2017-03-01

Endotoxin is a type of pyrogen that can be found in Gram-negative bacteria. Endotoxin can form a stable interaction with other biomolecules thus making its removal difficult especially during the production of biopharmaceutical drugs. The prevention of endotoxins from contaminating biopharmaceutical products is paramount as endotoxin contamination, even in small quantities, can result in fever, inflammation, sepsis, tissue damage and even lead to death. Highly sensitive and accurate detection of endotoxins are keys in the development of biopharmaceutical products derived from Gram-negative bacteria. It will facilitate the study of the intermolecular interaction of an endotoxin with other biomolecules, hence the selection of appropriate endotoxin removal strategies. Currently, most researchers rely on the conventional LAL-based endotoxin detection method. However, new methods have been and are being developed to overcome the problems associated with the LAL-based method. This review paper highlights the current research trends in endotoxin detection from conventional methods to newly developed biosensors. Additionally, it also provides an overview of the use of electron microscopy, dynamic light scattering (DLS), fluorescence resonance energy transfer (FRET) and docking programs in the endotoxin-protein analysis.

Nanopatterning on calixarene thin films via low-energy field-emission scanning probe lithography.

PubMed

He, Xiaoyue; Li, Peng; Liu, Pengchong; Zhang, Xiaoxian; Zhou, Xiangqian; Liu, Wei; Qiu, Xiaohui

2018-08-10

Field-emitted, low-energy electrons from the conducting tip of an atomic force microscope were adopted for nanolithography on calixarene ultrathin films coated on silicon wafers. A structural evolution from protrusion to depression down to a 30 nm spatial resolution was reproducibly obtained by tuning the sample voltage and exposure current in the lithography process. Close analyses of the profiles showed that the nanostructures formed by a single exposure with a high current are almost identical to those created by cumulative exposure with a lower current but an equal number of injected electrons. Surface potential imaging by Kelvin probe force microscopy found a negatively charged region surrounding the groove structures once the structures were formed. We conclude that the mechanism related to the formation of a temporary negative state and molecule decomposition, rather than thermal ablation, is responsible for the low-energy field-emission electron lithography on a calixarene molecular resist. We hope that our elucidation of the underlying mechanism is helpful for molecular resist design and further improving the reproducibility and throughput of nanolithography.

Update Direct-Strike Lightning Environment for Stockpile-to-Target Sequence (Second Revision)

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

Uman, Martin A.; Rakov, V. A.; Elisme, J. O.

2010-10-05

The University of Florida has surveyed all relevant publications reporting lightning characteristics and presents here an up-to-date version of the direct-strike lightning environment specifications for nuclear weapons published in 1989 by R. J. Fisher and M. A. Uman. Further, we present functional expressions for current vs. time, current derivative vs. time, second current derivative vs. time, charge transfer vs. time, and action integral (specific energy) vs. time for positive and negative first return strokes, for negative subsequent return strokes, and for positive and negative continuing currents; and we give sets of constants for these functional expressions so that the resultantmore » waveforms exhibit approximately the median and extreme lightning parameters presented in the updated direct strike environment. Fourier transforms of the return stroke current waveforms are presented. The results of our literature survey are included in three Appendices entitled Return Stroke Current, Continuing Current, and Positive Lightning.« less

Aberration of a negative ion beam caused by space charge effect.

PubMed

Miyamoto, K; Wada, S; Hatayama, A

2010-02-01

Aberrations are inevitable when the charged particle beams are extracted, accelerated, transmitted, and focused with electrostatic and magnetic fields. In this study, we investigate the aberration of a negative ion accelerator for a neutral beam injector theoretically, especially the spherical aberration caused by the negative ion beam expansion due to the space charge effect. The negative ion current density profiles with the spherical aberration are compared with those without the spherical aberration. It is found that the negative ion current density profiles in a log scale are tailed due to the spherical aberration.

Early trauma, negative affect, and anxious attachment: the role of metacognition.

PubMed

Myers, Samuel G; Wells, Adrian

2015-01-01

Metacognition is linked to the etiology and maintenance of negative emotions and psychological disorder in the Self-Regulatory Executive Function Model. Although there is significant evidence supporting the model, little is currently known about the situational factors for developing dysfunctional metacognitions. The current study explored the hypothesis that early aversive experiences might be important and also tested if metacognitions could mediate the relationship between such experiences and psychological symptoms. Three hundred and fifty non-clinical adults completed a retrospective early trauma measure, as well as measures of current metacognitive beliefs, negative affect, and anxious attachment. Early emotional abuse positively and significantly correlated with several metacognitive belief dimensions but other forms of early trauma did not. Metacognition fully mediated the relationship between emotional abuse and negative affect. Anxious attachment was also positively and significantly associated with metacognitive beliefs and specific relationships remained after controlling for early emotional abuse and current negative affect. Findings are consistent with the ideas that: (i) early negative experiences, and emotional abuse in particular, could be a factor in the formation of problematic metacognitions and (ii) these metacognitions may be important in determining the effects of abuse on subsequent psychological symptoms.

Improving compound-protein interaction prediction by building up highly credible negative samples.

PubMed

Liu, Hui; Sun, Jianjiang; Guan, Jihong; Zheng, Jie; Zhou, Shuigeng

2015-06-15

Computational prediction of compound-protein interactions (CPIs) is of great importance for drug design and development, as genome-scale experimental validation of CPIs is not only time-consuming but also prohibitively expensive. With the availability of an increasing number of validated interactions, the performance of computational prediction approaches is severely impended by the lack of reliable negative CPI samples. A systematic method of screening reliable negative sample becomes critical to improving the performance of in silico prediction methods. This article aims at building up a set of highly credible negative samples of CPIs via an in silico screening method. As most existing computational models assume that similar compounds are likely to interact with similar target proteins and achieve remarkable performance, it is rational to identify potential negative samples based on the converse negative proposition that the proteins dissimilar to every known/predicted target of a compound are not much likely to be targeted by the compound and vice versa. We integrated various resources, including chemical structures, chemical expression profiles and side effects of compounds, amino acid sequences, protein-protein interaction network and functional annotations of proteins, into a systematic screening framework. We first tested the screened negative samples on six classical classifiers, and all these classifiers achieved remarkably higher performance on our negative samples than on randomly generated negative samples for both human and Caenorhabditis elegans. We then verified the negative samples on three existing prediction models, including bipartite local model, Gaussian kernel profile and Bayesian matrix factorization, and found that the performances of these models are also significantly improved on the screened negative samples. Moreover, we validated the screened negative samples on a drug bioactivity dataset. Finally, we derived two sets of new interactions by training an support vector machine classifier on the positive interactions annotated in DrugBank and our screened negative interactions. The screened negative samples and the predicted interactions provide the research community with a useful resource for identifying new drug targets and a helpful supplement to the current curated compound-protein databases. Supplementary files are available at: http://admis.fudan.edu.cn/negative-cpi/. © The Author 2015. Published by Oxford University Press.

Parental communication style and family relationships in children of bipolar parents.

PubMed

Vance, Yvonne H; Huntley Jones, Steven; Espie, Jonathan; Bentall, Richard; Tai, Sara

2008-09-01

To examine relationships between parental communication styles and family environment in parents with bipolar disorder (BD) and their children (CBP). On measures of parental communication styles and family environment, 20 BD parents and their 23 children (CBP) were compared to controls. Children completed a current mood measure. BD parents endorsed more negative communication styles and were less expressive than controls. CBP presented with more current or lifetime mood disorder diagnoses than control children (CC). Current depressive mood was associated with different perceptions of family environment for both CBP and CC. This familial high risk design indicated differences in family environment, parenting style, and in children of bipolar parents' perception of their family environment as it relates to their current mood.

Fear of negative evaluation modulates electrocortical and behavioral responses when anticipating social evaluative feedback.

PubMed

Van der Molen, Melle J W; Poppelaars, Eefje S; Van Hartingsveldt, Caroline T A; Harrewijn, Anita; Gunther Moor, Bregtje; Westenberg, P Michiel

2013-01-01

Cognitive models posit that the fear of negative evaluation (FNE) is a hallmark feature of social anxiety. As such, individuals with high FNE may show biased information processing when faced with social evaluation. The aim of the current study was to examine the neural underpinnings of anticipating and processing social-evaluative feedback, and its correlates with FNE. We used a social judgment paradigm in which female participants (N = 31) were asked to indicate whether they believed to be socially accepted or rejected by their peers. Anticipatory attention was indexed by the stimulus preceding negativity (SPN), while the feedback-related negativity and P3 were used to index the processing of social-evaluative feedback. Results provided evidence of an optimism bias in social peer evaluation, as participants more often predicted to be socially accepted than rejected. Participants with high levels of FNE needed more time to provide their judgments about the social-evaluative outcome. While anticipating social-evaluative feedback, SPN amplitudes were larger for anticipated social acceptance than for social rejection feedback. Interestingly, the SPN during anticipated social acceptance was larger in participants with high levels of FNE. None of the feedback-related brain potentials correlated with the FNE. Together, the results provided evidence of biased information processing in individuals with high levels of FNE when anticipating (rather than processing) social-evaluative feedback. The delayed response times in high FNE individuals were interpreted to reflect augmented vigilance imposed by the upcoming social-evaluative threat. Possibly, the SPN constitutes a neural marker of this vigilance in females with higher FNE levels, particularly when anticipating social acceptance feedback.

High-voltage space-plasma interactions measured on the PASP Plus test arrays

NASA Astrophysics Data System (ADS)

Guidice, Donald A.

1995-10-01

The Photovoltaic Array Space Power Plus Diagnostics (PASP Plus) experiment was developed by the Air Force's Phillips Laboratory with support from NASA's Lewis Research Center. It was launched on the Advanced Photovoltaic and Electronics EXperiments (APEX) satellite on August 3, 1994 into a 70 degree inclination, 363 km by 2550 km elliptical orbit. This orbit allows the investigation of space plasma effects on high-voltage operation (leakage current at positive voltages and arcing at negative voltages) in the perigee region. PASP Plus is testing twelve solar arrays. There are four planar Si arrays: an old standard type (used as a reference), the large-cell Space Station Freedom (SSF) array, a thin 'APSA' array, and an amorphous Si array. Next are three GaAs on Ge planar arrays and three new material planar arrays, including InP and two multijunction types. Finally, there are two concentrator arrays: a reflective-focusing Mini-Cassegrainian and a Fresnel-lens focusing Mini-Dome. PASP Plus's diagnostic sensors include: Langmuir probe to measure plasma density, an electrostatic analyzer (ESA) to measure the 30 eV to 30 KeV electron/ion spectra and determine vehicle negative potential during positive biasing, and a transient pulse monitor (TPM) to characterize the arcs that occur during the negative biasing. Through positive biasing of its test arrays, PASP Plus investigated the snapover phenomenon, which took place over the range of +100 to +300 V. It was found that array configurations where the interconnects are shielded from the space plasma (i.e., the concentrators or arrays with 'wrap-through' connectors) have lower leakage current. The concentrators exhibited negligible leakage current over the whole range up to +500 V. In the case of two similar GaAs on Ge arrays, the one with 'wrap-through' connectors had lower leakage current than the one with conventional interconnects. Through negative biasing, PASP Plus investigated the arcing rates of its test arrays. The standard Si array, with its old construction (exposed rough-surface interconnects), arced significantly over a wide voltage and plasma-density range. The other arrays arced at very low rates, mostly at voltages greater than -350 V and plasma densities near or greater than 10(exp 5)/cm(exp -3). AS expected according to theory, arcing was more prevalent when array temperatures were cold (based on biasing in eclipse).

High-voltage space-plasma interactions measured on the PASP Plus test arrays

NASA Technical Reports Server (NTRS)

Guidice, Donald A.

1995-01-01

The Photovoltaic Array Space Power Plus Diagnostics (PASP Plus) experiment was developed by the Air Force's Phillips Laboratory with support from NASA's Lewis Research Center. It was launched on the Advanced Photovoltaic and Electronics EXperiments (APEX) satellite on August 3, 1994 into a 70 degree inclination, 363 km by 2550 km elliptical orbit. This orbit allows the investigation of space plasma effects on high-voltage operation (leakage current at positive voltages and arcing at negative voltages) in the perigee region. PASP Plus is testing twelve solar arrays. There are four planar Si arrays: an old standard type (used as a reference), the large-cell Space Station Freedom (SSF) array, a thin 'APSA' array, and an amorphous Si array. Next are three GaAs on Ge planar arrays and three new material planar arrays, including InP and two multijunction types. Finally, there are two concentrator arrays: a reflective-focusing Mini-Cassegrainian and a Fresnel-lens focusing Mini-Dome. PASP Plus's diagnostic sensors include: Langmuir probe to measure plasma density, an electrostatic analyzer (ESA) to measure the 30 eV to 30 KeV electron/ion spectra and determine vehicle negative potential during positive biasing, and a transient pulse monitor (TPM) to characterize the arcs that occur during the negative biasing. Through positive biasing of its test arrays, PASP Plus investigated the snapover phenomenon, which took place over the range of +100 to +300 V. It was found that array configurations where the interconnects are shielded from the space plasma (i.e., the concentrators or arrays with 'wrap-through' connectors) have lower leakage current. The concentrators exhibited negligible leakage current over the whole range up to +500 V. In the case of two similar GaAs on Ge arrays, the one with 'wrap-through' connectors had lower leakage current than the one with conventional interconnects. Through negative biasing, PASP Plus investigated the arcing rates of its test arrays. The standard Si array, with its old construction (exposed rough-surface interconnects), arced significantly over a wide voltage and plasma-density range. The other arrays arced at very low rates, mostly at voltages greater than -350 V and plasma densities near or greater than 10(exp 5)/cm(exp -3). AS expected according to theory, arcing was more prevalent when array temperatures were cold (based on biasing in eclipse).

Effect of atomic layer deposition temperature on current conduction in Al{sub 2}O{sub 3} films formed using H{sub 2}O oxidant

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

Hiraiwa, Atsushi, E-mail: hiraiwa@aoni.waseda.jp, E-mail: qs4a-hriw@asahi-net.or.jp; Matsumura, Daisuke; Kawarada, Hiroshi, E-mail: kawarada@waseda.jp

To develop high-performance, high-reliability gate insulation and surface passivation technologies for wide-bandgap semiconductor devices, the effect of atomic layer deposition (ALD) temperature on current conduction in Al{sub 2}O{sub 3} films is investigated based on the recently proposed space-charge-controlled field emission model. Leakage current measurement shows that Al{sub 2}O{sub 3} metal-insulator-semiconductor capacitors formed on the Si substrates underperform thermally grown SiO{sub 2} capacitors at the same average field. However, using equivalent oxide field as a more practical measure, the Al{sub 2}O{sub 3} capacitors are found to outperform the SiO{sub 2} capacitors in the cases where the capacitors are negatively biased andmore » the gate material is adequately selected to reduce virtual dipoles at the gate/Al{sub 2}O{sub 3} interface. The Al{sub 2}O{sub 3} electron affinity increases with the increasing ALD temperature, but the gate-side virtual dipoles are not affected. Therefore, the leakage current of negatively biased Al{sub 2}O{sub 3} capacitors is approximately independent of the ALD temperature because of the compensation of the opposite effects of increased electron affinity and permittivity in Al{sub 2}O{sub 3}. By contrast, the substrate-side sheet of charge increases with increasing ALD temperature above 210 °C and hence enhances the current of positively biased Al{sub 2}O{sub 3} capacitors more significantly at high temperatures. Additionally, an anomalous oscillatory shift of the current-voltage characteristics with ALD temperature was observed in positively biased capacitors formed by low-temperature (≤210 °C) ALD. This shift is caused by dipoles at the Al{sub 2}O{sub 3}/underlying SiO{sub 2} interface. Although they have a minimal positive-bias leakage current, the low-temperature-grown Al{sub 2}O{sub 3} films cause the so-called blisters problem when heated above 400 °C. Therefore, because of the absence of blistering, a 450 °C ALD process is presently the most promising technology for growing high-reliability Al{sub 2}O{sub 3} films.« less

Positive and negative emotional eating have different associations with overeating and binge eating: Construction and validation of the Positive-Negative Emotional Eating Scale.

PubMed

Sultson, Hedvig; Kukk, Katrin; Akkermann, Kirsti

2017-09-01

Research on emotional eating mostly focuses on negative emotions. Much less is known about how positive emotions relate to overeating and binge eating (BE). The aim of the current study was to construct a scale for positive and negative emotional eating and to assess its predictive validity. In study 1, the Positive-Negative Emotional Eating Scale (PNEES) was constructed and tested on 531 women, who also completed Eating Disorders Assessment Scale (EDAS). Results showed that a two-factor model constituting Positive emotional eating (PNEES-P) and Negative emotional eating (PNEES-N) fit the data well. PNEES-N also showed good convergent validity in assessing binge eating, correlating highly with EDAS subscale Binge eating. Further, a path analysis showed that after controlling for the mediating effect of PNEES-N, PNEES-P continued to significantly predict binge eating. In study 2 (N = 60), experience sampling method was used to assess overeating and BE in the natural environment. Palmtop computers were given to participants for a three-day study period that prompted them with questions regarding emotional experience, overeating, and BE. Results indicated that PNEES-P significantly predicted overeating, whereas PNEES-N predicted overeating and BE episodes only in a subsample of women who had experienced at least one overeating or BE episode. Thus, positive and negative emotional eating might have different relations with overeating and BE, with the latter being more characteristic of the severity/frequency of overeating and BE. New assessment tools that in addition to negative emotional eating also address positive emotional eating could be of potential help in planning intervention. Further, the tendency to overeat in response to positive emotions could be integrated into current models of eating disorders, especially when addressing relapse prevention. Copyright © 2017 Elsevier Ltd. All rights reserved.

Attachment insecurity, biased perceptions of romantic partners' negative emotions, and hostile relationship behavior.

PubMed

Overall, Nickola C; Fletcher, Garth J O; Simpson, Jeffry A; Fillo, Jennifer

2015-05-01

In the current research, we tested the extent to which attachment insecurity produces inaccurate and biased perceptions of intimate partners' emotions and whether more negative perceptions of partners' emotions elicit the damaging behavior often associated with attachment insecurity. Perceptions of partners' emotions as well as partners' actual emotions were assessed multiple times in couples' conflict discussions (Study 1) and daily during a 3-week period in 2 independent samples (Study 2). Using partners' reports of their own emotional experiences as the accuracy benchmark, we simultaneously tested whether attachment insecurity was associated with the degree to which individuals (a) accurately detected shifts in their partners' negative emotions (tracking accuracy), and (b) perceived their partners were feeling more negative relationship-related emotions than they actually experienced (directional bias). Highly avoidant perceivers were equally accurate at tracking their partners' changing emotions compared to less avoidant individuals (tracking accuracy), but they overestimated the intensity of their partners' negative emotions to a greater extent than less avoidant individuals (directional bias). In addition, more negative perceptions of partners' emotions triggered more hostile and defensive behavior in highly avoidant perceivers both during conflict discussions (Study 1) and in daily life (Study 2). In contrast, attachment anxiety was not associated with tracking accuracy, directional bias, or hostile reactions to perceptions of their partners' negative emotions. These findings demonstrate the importance of assessing biased perceptions in actual relationship interactions and reveal that biased perceptions play an important role in activating the defenses of avoidantly attached people. (c) 2015 APA, all rights reserved).

Undifferentiated negative affect and impulsivity in borderline personality and depressive disorders: A momentary perspective.

PubMed

Tomko, Rachel L; Lane, Sean P; Pronove, Lisa M; Treloar, Hayley R; Brown, Whitney C; Solhan, Marika B; Wood, Phillip K; Trull, Timothy J

2015-08-01

Individuals with borderline personality disorder (BPD) often report experiencing several negative emotions simultaneously, an indicator of "undifferentiated" negative affect. The current study examined the relationship between undifferentiated negative affect and impulsivity. Participants with a current BPD (n = 67) or depressive disorder (DD; n = 38) diagnosis carried an electronic diary for 28 days, reporting on emotions and impulsivity when randomly prompted (up to 6 times per day). Undifferentiated negative affect was quantified using momentary intraclass correlation coefficients, which indicated how consistently negative emotion items were rated across fear, hostility, and sadness subscales. Undifferentiated negative affect at the occasion-level, day-level, and across 28 days was used to predict occasion-level impulsivity. Multilevel modeling was used to test the hypothesis that undifferentiated negative emotion would be a significant predictor of momentary impulsivity above and beyond levels of overall negative affect. Undifferentiated negative affect at the occasion and day levels were significant predictors of occasion-level impulsivity, but undifferentiated negative affect across the 28-day study period was only marginally significant. Results did not differ depending on BPD or DD status, though individuals with BPD did report significantly greater momentary impulsivity and undifferentiated negative affect. Undifferentiated negative affect may increase risk for impulsivity among individuals with BPD and depressive disorders, and the current data suggest that this process can be relatively immediate as well as cumulative over the course of a day. This research supports the consideration of undifferentiated negative affect as a transdiagnostic construct, but one that may be particularly relevant for those with BPD. (c) 2015 APA, all rights reserved).

Undifferentiated Negative Affect and Impulsivity in Borderline Personality and Depressive Disorders: A Momentary Perspective

PubMed Central

Pronove, Lisa M.; Treloar, Hayley R.; Brown, Whitney C.; Solhan, Marika B.; Wood, Phillip K.; Trull, Timothy J.

2015-01-01

Individuals with borderline personality disorder (BPD) often report experiencing several negative emotions simultaneously, an indicator of “undifferentiated” negative affect. The current study examined the relationship between undifferentiated negative affect and impulsivity. Participants with a current BPD (n = 67) or depressive disorder (DD; n = 38) diagnosis carried an electronic diary for 28 days, reporting on emotions and impulsivity when randomly prompted (up to 6 times per day). Undifferentiated negative affect was quantified using momentary intraclass correlation coefficients, which indicated how consistently negative emotion items were rated across fear, hostility, and sadness subscales. Undifferentiated negative affect at the occasion-level, day-level, and across 28 days was used to predict occasion-level impulsivity. Multilevel modeling was used to test the hypothesis that undifferentiated negative emotion would be a significant predictor of momentary impulsivity above and beyond levels of overall negative affect. Undifferentiated negative affect at the occasion and day levels were significant predictors of occasion-level impulsivity, but undifferentiated negative affect across the 28-day study period was only marginally significant. Results did not differ depending on BPD or DD status, though BPD individuals did report significantly greater momentary impulsivity and undifferentiated negative affect. Undifferentiated negative affect may increase risk for impulsivity among individuals with BPD and depressive disorders, and the current data suggest that this process can be relatively immediate as well as cumulative over the course of a day. This research supports the consideration of undifferentiated negative affect as a transdiagnostic construct, but one that may be particularly relevant for those with BPD. PMID:26147324

Longitudinal predictors of subjective recovery in psychosis.

PubMed

Law, Heather; Shryane, Nick; Bentall, Richard P; Morrison, Anthony P

2016-07-01

Research has highlighted the importance of recovery as defined by the service user, and suggests a link to negative emotion, although little is known about the role of negative emotion in predicting subjective recovery. To investigate longitudinal predictors of variability in recovery scores with a focus on the role of negative emotion. Participants (n = 110) with experience of psychosis completed measures of psychiatric symptoms, social functioning, subjective recovery, depression, hopelessness and self-esteem at baseline and 6 months later. Path analysis was used to examine predictive factors for recovery and negative emotion. Subjective recovery scores were predicted by negative emotion, positive self-esteem and hopelessness, and to a lesser extent by symptoms and functioning. Current recovery score was not predicted by past recovery score after accounting for past symptoms, current hopelessness and current positive self-esteem. Psychosocial factors and negative emotion appear to be the strongest longitudinal predictors of variation in subjective recovery, rather than psychiatric symptoms. © The Royal College of Psychiatrists 2016.

Interaction of high voltage surfaces with the space plasma

NASA Technical Reports Server (NTRS)

Kaufman, H. R.; Robinson, R. S.

1980-01-01

High voltage solar arrays provide spacecraft power while optimizing mass and power efficiency. Operating such arrays in the space plasma environment can result in anomalously large currents being collected through insulation defects. Two thicknesses of the insulating material were tested, with no effect found due to insulator thickness. In these tests the polyimide thickness was always much less than the pinhole diameter. The pinhole area was varied over an area range of more than 30:1. It was found that the current collected was independent of the pinhole area for hole diameters from 0.35 to 2.0 mm. Two types of adhesives were tried in two different configurations. The adhesives were chosen for their extreme difference in vacuum qualifications. Neither adhesive types nor configuration made a significant difference in current collection. The temperature of the insulating material was also varied. It was found that current collection decreased with increasing temperature. Tests were conducted to see if pinhole current collection decreased with time, as was indicated by the effects of several short tests. Current was collected for over four hours while the conductor potential was held constant at 1000 volts. A smooth decrease with time was not observed, but rather a roughly constant current collection with brief surges to high values. Tests were also conducted with the simulated solar cell biased negative. The current was found to be proportional to pinhole area.

Development of a high average current polarized electron source with long cathode operational lifetime

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

C. K. Sinclair; P. A. Adderley; B. M. Dunham

Substantially more than half of the electromagnetic nuclear physics experiments conducted at the Continuous Electron Beam Accelerator Facility of the Thomas Jefferson National Accelerator Facility (Jefferson Laboratory) require highly polarized electron beams, often at high average current. Spin-polarized electrons are produced by photoemission from various GaAs-based semiconductor photocathodes, using circularly polarized laser light with photon energy slightly larger than the semiconductor band gap. The photocathodes are prepared by activation of the clean semiconductor surface to negative electron affinity using cesium and oxidation. Historically, in many laboratories worldwide, these photocathodes have had short operational lifetimes at high average current, and havemore » often deteriorated fairly quickly in ultrahigh vacuum even without electron beam delivery. At Jefferson Lab, we have developed a polarized electron source in which the photocathodes degrade exceptionally slowly without electron emission, and in which ion back bombardment is the predominant mechanism limiting the operational lifetime of the cathodes during electron emission. We have reproducibly obtained cathode 1/e dark lifetimes over two years, and 1/e charge density and charge lifetimes during electron beam delivery of over 2?105???C/cm2 and 200 C, respectively. This source is able to support uninterrupted high average current polarized beam delivery to three experimental halls simultaneously for many months at a time. Many of the techniques we report here are directly applicable to the development of GaAs photoemission electron guns to deliver high average current, high brightness unpolarized beams.« less

Narrative Centrality and Negative Affectivity: Independent and Interactive Contributors to Stress Reactions

PubMed Central

Rubin, David C.; Boals, Adriel; Hoyle, Rick H.

2014-01-01

Reactions to stressful negative events have long been studied using approaches based on either the narrative interpretation of the event or the traits of the individual. Here, we integrate these two approaches by using individual differences measures of both the narrative interpretation of the stressful event as central to one’s life and the personality characteristic of negative affectivity. We show that they each have independent contributions to stress reactions, and that high levels on both produce greater than additive effects. The effects on posttraumatic stress symptoms are substantial for both undergraduates (Study 1, n = 2,296; Study 3, n = 488) and veterans (Study 2, n = 104), with mean levels for participants low on both measures near floor on posttraumatic stress symptoms and those high on both measures scoring at or above diagnostic thresholds. Study 3 included three measures of narrative centrality and three of negative affectivity to demonstrate that the effects were not limited to a single measure. In Study 4 (n = 987), measures associated with symptoms of posttraumatic stress correlated substantially with either with measures of narrative centrality or measures of negative affectivity. The concepts of narrative centrality and negative affectivity and the results are consistent with findings from clinical populations using similar measures and with current approaches to therapy. In broad non-clinical populations, such as those used here, the results suggest that we might be able to substantially increase our ability to account for the severity of stress response by including both concepts. PMID:24294867

SABRE modification to a higher voltage high impedance inductive voltage adder (IVA)

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

Mazarakis, M.G.; Smith, D.L.; Poukey, J.W.

The SABRE accelerator was originally designed to operate as low impedance voltage adder with 40-ohm maximum output impedance in negative polarity operation and approximately 20 ohm in positive polarity. Because of the low impedance and higher than expected energy losses in the pulse forming network, the operating input cavity voltage is of the order of 800 kV which limits the total output voltage to {approximately} 8 MV for negative polarity and 5 to 6 MV for positive polarity. The modifications presented here aim to increase the output voltage in both polarities. A new high impedance central electrode was designed capablemore » of operating both in negative and positive polarities, and the number of pulse forming lines feeding the inductively isolated cavities was reduced to half. These modifications were recently tested in positive polarity. An increase in the total accelerating voltage from 5.5 MV to 9 MV was observed while stressing all components to the level required to achieve 12 MV in negative polarity. In these experiments only 65% of the usual operating intermediate store capacitor voltage was necessary (1.7 MV instead of 2.6 MV). Currently, the device is reconfigured for negative polarity tests. The cavities are rotated by 180{degree} and a 17-inch spool is added at the base of the cantilevered center electrode (cathode electrode). Positive and negative polarity results are presented and compared with simulations.« less

Characteristics of Currents and Electric Fields Associated with the Initial Stage of Upward Lightning

NASA Astrophysics Data System (ADS)

Watanabe, N.; Nag, A.; Diendorfer, G.; Pichler, H.; Schulz, W.

2017-12-01

There is increasing interest in understanding processes associated with the initiation of upward lightning from tall structures. Characterization of such processes is essential for the development of appropriate models. We examine current and electric field waveforms for 15 negative upward flashes occurring in 2007-2009 initiated from the Gaisberg Tower located in Salzburg, Austria. Current was measured at the top of the tower using a 0.25 mΩ shunt. Electric field was measured simultaneously at close (170 m from the tower) and far (79 km from the tower in 2007 and 109 km in 2008-2009) distances. The initial stage (IS) of these flashes comprised of relatively slowly varying "background" current (having durations ranging from 132 to 692 ms), with faster, more impulsive current variations (pulses having durations ranging from 4.7 µs to 22.9 ms) overlaid on this background current. In five of the 15 (33%) flashes, this IS background current was negative while in the other ten (67%) flashes, the current was bipolar (changing between negative and positive values). 150 current pulses occurred during the IS of these 15 flashes, of which 28 (19%) were positive bipolar (positive initial polarity with a negative opposite polarity overshoot), 5 (3.3%) were positive unipolar (positive initial polarity with no opposite polarity overshoot), and 117 (78%) were negative unipolar. No negative bipolar pulses were found. The median peak current and risetime for the 28 bipolar pulses were 0.74 kA and 2.8 µs, respectively, and those for the 122 unipolar pulses were 0.87 kA and 70 µs, respectively. Generally speaking, majority of the pulses occurring at the beginning of the initial stage were lower-amplitude positive bipolar, while higher-amplitude unipolar pulses were more likely to occur at later times. These 150 IS current pulses produced 133 detectable electric field change signatures at the near station and 59 at the far station (all recorded at 79 km in 12 flashes occurring in 2007). We will examine in detail the characteristics of these electric field pulses in order to gain insights into the mechanisms of the underlying processes.

Battery paste compositions and electrochemical cells for use therewith

DOEpatents

Olson, J.B.

1999-02-16

An improved battery paste composition and a lead-acid electrochemical cell which incorporates the composition are disclosed. The cell includes a positive current collector and a negative current collector which are each coated with a paste containing one or more lead-containing compositions and a paste vehicle to form a positive plate and a negative plate. An absorbent electrolyte-containing separator member may also be positioned between the positive and negative plates. The paste on the positive current collector, the negative current collector, or both further includes a special additive consisting of polyvinyl sulfonic acid or salts thereof which provides many benefits including improved battery cycle life, increased charge capacity, and enhanced overall stability. The additive also makes the pastes smoother and more adhesive, thereby improving the paste application process. The paste compositions of interest may be used in conventional flat-plate cells or in spirally wound batteries with equal effectiveness. 2 figs.

Battery paste compositions and electrochemical cells for use therewith

DOEpatents

Olson, John B.

1999-12-07

An improved battery paste composition and a lead-acid electrochemical cell which incorporates the composition. The cell includes a positive current collector and a negative current collector which are each coated with a paste containing one or more lead-containing compositions and a paste vehicle to form a positive plate and a negative plate. An absorbent electrolyte-containing separator member may also be positioned between the positive and negative plates. The paste on the positive current collector, the negative current collector, or both further includes a special additive consisting of polyvinylsulfonic acid or salts thereof which provides many benefits including improved battery cycle life, increased charge capacity, and enhanced overall stability. The additive also makes the pastes smoother and more adhesive, thereby improving the paste application process. The paste compositions of interest may be used in conventional flat-plate cells or in spirally wound batteries with equal effectiveness.

Battery paste compositions and electrochemical cells for use therewith

DOEpatents

Olson, John B.

1999-02-16

An improved battery paste composition and a lead-acid electrochemical cell which incorporates the composition. The cell includes a positive current collector and a negative current collector which are each coated with a paste containing one or more lead-containing compositions and a paste vehicle to form a positive plate and a negative plate. An absorbent electrolyte-containing separator member may also be positioned between the positive and negative plates. The paste on the positive current collector, the negative current collector, or both further includes a special additive consisting of polyvinylsulfonic acid or salts thereof which provides many benefits including improved battery cycle life, increased charge capacity, and enhanced overall stability. The additive also makes the pastes smoother and more adhesive, thereby improving the paste application process. The paste compositions of interest may be used in conventional flat-plate cells or in spirally wound batteries with equal effectiveness.

Depth Profiles of Mg, Si, and Zn Implants in GaN by Trace Element Accelerator Mass Spectrometry

NASA Astrophysics Data System (ADS)

Ravi Prasad, G. V.; Pelicon, P.; Mitchell, L. J.; McDaniel, F. D.

2003-08-01

GaN is one of the most promising electronic materials for applications requiring high-power, high frequencies, or high-temperatures as well as opto-electronics in the blue to ultraviolet spectral region. We have recently measured depth profiles of Mg, Si, and Zn implants in GaN substrates by the TEAMS particle counting method for both matrix and trace elements, using a gas ionization chamber. Trace Element Accelerator Mass Spectrometry (TEAMS) is a combination of Secondary Ion Mass Spectrometry (SIMS) and Accelerator Mass Spectrometry (AMS) to measure trace elements at ppb levels. Negative ions from a SIMS like source are injected into a tandem accelerator. Molecular interferences inherent with the SIMS method are eliminated in the TEAMS method. Negative ion currents are extremely low with GaN as neither gallium nor nitrogen readily forms negative ions making the depth profile measurements more difficult. The energies of the measured ions are in the range of 4-8 MeV. A careful selection of mass/charge ratios of the detected ions combined with energy-loss behavior of the ions in the ionization chamber eliminated molecular interferences.

Social anxiety and heavy situational drinking: coping and conformity motives as multiple mediators.

PubMed

Terlecki, Meredith A; Buckner, Julia D

2015-01-01

Individuals with clinically elevated social anxiety are at greater risk for alcohol use disorder, and the relation between social anxiety and drinking problems is at least partially accounted for by drinking more in negative emotional (e.g., feeling sad or angry) and personal/intimate (e.g., before sexual intercourse) situations. Identification of cognitive/motivational factors related to drinking in these high-risk situations could inform the development of treatment and prevention interventions for these high-risk drinkers. The current cross-sectional study examined the mediating effect of drinking motives on the relationship between social anxiety and drinking these high-risk situations among undergraduates (N=232). Clinically elevated social anxiety was associated with greater coping and conformity motives. Both coping and conformity motives mediated the relation between social anxiety and heavier alcohol consumption in negative emotional and personal/intimate contexts. Multiple mediation analyses indicated that these motives work additively to mediate the social anxiety-drinking situations relationship, such that heavy situational drinking among undergraduates with clinically elevated social anxiety can be jointly attributed to desire to cope with negative affect and to avoid social scrutiny. Copyright © 2014 Elsevier Ltd. All rights reserved.

Individual differences in neural responses to social rejection: the joint effect of self-esteem and attentional control

PubMed Central

Hooker, Christine I.; Miyakawa, Asako; Verosky, Sara; Luerssen, Anna; Ayduk, Özlem N.

2012-01-01

Individuals with low self-esteem have been found to react more negatively to signs of interpersonal rejection than those with high self-esteem. However, previous research has found that individual differences in attentional control can attenuate negative reactions to social rejection among vulnerable, low self-esteem individuals. The current fMRI study sought to elucidate the neurobiological substrate of this buffering effect. We hypothesized and found that while looking at scenes of social rejection (vs negative scenes) low self-esteem high attentional control individuals engaged the rostral anterior cingulate cortex (rACC), an area of the brain associated with emotional control, more than their low self-esteem low attentional control peers. Furthermore, we found that low self-esteem high attentional control individuals evaluated social rejection as less arousing and less rejecting in a separate behavioral task. Importantly, activation in the rACC fully mediated the relationship between the interaction of self-esteem and attentional control and emotional evaluations, suggesting that the rACC activation underlies the buffering effects of attentional control. Results are discussed in terms of individual differences in emotional vulnerability and protection and by highlighting the role of rACC in emotion regulation. PMID:21609969

Mental models of audit and feedback in primary care settings.

PubMed

Hysong, Sylvia J; Smitham, Kristen; SoRelle, Richard; Amspoker, Amber; Hughes, Ashley M; Haidet, Paul

2018-05-30

Audit and feedback has been shown to be instrumental in improving quality of care, particularly in outpatient settings. The mental model individuals and organizations hold regarding audit and feedback can moderate its effectiveness, yet this has received limited study in the quality improvement literature. In this study we sought to uncover patterns in mental models of current feedback practices within high- and low-performing healthcare facilities. We purposively sampled 16 geographically dispersed VA hospitals based on high and low performance on a set of chronic and preventive care measures. We interviewed up to 4 personnel from each location (n = 48) to determine the facility's receptivity to audit and feedback practices. Interview transcripts were analyzed via content and framework analysis to identify emergent themes. We found high variability in the mental models of audit and feedback, which we organized into positive and negative themes. We were unable to associate mental models of audit and feedback with clinical performance due to high variance in facility performance over time. Positive mental models exhibit perceived utility of audit and feedback practices in improving performance; whereas, negative mental models did not. Results speak to the variability of mental models of feedback, highlighting how facilities perceive current audit and feedback practices. Findings are consistent with prior research  in that variability in feedback mental models is associated with lower performance.; Future research should seek to empirically link mental models revealed in this paper to high and low levels of clinical performance.

Negative Differential Conductance & Hot-Carrier Avalanching in Monolayer WS2 FETs

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

He, G.; Nathawat, J.; Kwan, C. -P.

The high field phenomena of inter-valley transfer and avalanching breakdown have long been exploited in devices based on conventional semiconductors. In this Article, we demonstrate the manifestation of these effects in atomically-thin WS 2 field-effect transistors. The negative differential conductance exhibits all of the features familiar from discussions of this phenomenon in bulk semiconductors, including hysteresis in the transistor characteristics and increased noise that is indicative of travelling high-field domains. It is also found to be sensitive to thermal annealing, a result that we attribute to the influence of strain on the energy separation of the different valleys involved inmore » hot-electron transfer. This idea is supported by the results of ensemble Monte Carlo simulations, which highlight the sensitivity of the negative differential conductance to the equilibrium populations of the different valleys. At high drain currents (>10 μA/μm) avalanching breakdown is also observed, and is attributed to trap-assisted inverse Auger scattering. This mechanism is not normally relevant in conventional semiconductors, but is possible in WS 2 due to the narrow width of its energy bands. The various results presented here suggest that WS 2 exhibits strong potential for use in hot-electron devices, including compact high-frequency sources and photonic detectors.« less

Negative Differential Conductance & Hot-Carrier Avalanching in Monolayer WS2 FETs

DOE PAGES

He, G.; Nathawat, J.; Kwan, C. -P.; ...

2017-09-12

The high field phenomena of inter-valley transfer and avalanching breakdown have long been exploited in devices based on conventional semiconductors. In this Article, we demonstrate the manifestation of these effects in atomically-thin WS 2 field-effect transistors. The negative differential conductance exhibits all of the features familiar from discussions of this phenomenon in bulk semiconductors, including hysteresis in the transistor characteristics and increased noise that is indicative of travelling high-field domains. It is also found to be sensitive to thermal annealing, a result that we attribute to the influence of strain on the energy separation of the different valleys involved inmore » hot-electron transfer. This idea is supported by the results of ensemble Monte Carlo simulations, which highlight the sensitivity of the negative differential conductance to the equilibrium populations of the different valleys. At high drain currents (>10 μA/μm) avalanching breakdown is also observed, and is attributed to trap-assisted inverse Auger scattering. This mechanism is not normally relevant in conventional semiconductors, but is possible in WS 2 due to the narrow width of its energy bands. The various results presented here suggest that WS 2 exhibits strong potential for use in hot-electron devices, including compact high-frequency sources and photonic detectors.« less

Predictors of self-reported negative mood following a depressive mood induction procedure across previously depressed, currently anxious, and control individuals.

PubMed

Scherrer, Martin C; Dobson, Keith S; Quigley, Leanne

2014-09-01

This study identified and examined a set of potential predictors of self-reported negative mood following a depressive mood induction procedure (MIP) in a sample of previously depressed, clinically anxious, and control participants. The examined predictor variables were selected on the basis of previous research and theories of depression, and included symptoms of depression and anxiety, negative and positive affect, negative and positive automatic thoughts, dysfunctional beliefs, rumination, self-concept, and occurrence and perceived unpleasantness of recent negative events. The sample consisted of 33 previously depressed, 22 currently anxious, and 26 non-clinical control participants, recruited from community sources. Participant group status was confirmed through structured diagnostic interviews. Participants completed the Velten negative self-statement MIP as well as self-report questionnaires of affective, cognitive, and psychosocial variables selected as potential predictors of mood change. Symptoms of anxiety were associated with increased self-reported negative mood shift following the MIP in previously depressed participants, but not clinically anxious or control participants. Increased occurrence of recent negative events was a marginally significant predictor of negative mood shift for the previously depressed participants only. None of the other examined variables was significant predictors of MIP response for any of the participant groups. These results identify factors that may increase susceptibility to negative mood states in previously depressed individuals, with implications for theory and prevention of relapse to depression. The findings also identify a number of affective, cognitive, and psychosocial variables that do not appear to influence mood change following a depressive MIP in previously depressed, currently anxious, and control individuals. Limitations of the study and directions for future research are discussed. Current anxiety symptomatology was a significant predictor and occurrence of recent negative events was a marginally significant predictor of greater negative mood shift following the depressive mood induction for previously depressed individuals. None of the examined variables predicted change in mood following the depressive mood induction for currently anxious or control individuals. These results suggest that anxiety symptoms and experience with negative events may increase risk for experiencing depressive mood states among individuals with a vulnerability to depression. The generalizability of the present results to individuals with comorbid depression and anxiety is limited. Future research employing appropriate statistical approaches for confirmatory research is needed to test and confirm the present results. © 2014 The British Psychological Society.

Does counselling improve uptake of long-term and permanent contraceptive methods in a high HIV-prevalence setting?

PubMed Central

Dudley, Lilian; Makumucha, Courage; Dlamini, Phatisizwe; Moyo, Sihle; Bhembe, Sibongiseni

2015-01-01

Abstract Background Studies have shown a reduced uptake of contraceptive methods in HIV-positive women of childbearing age, mainly because of unmet needs that may be a result of poor promotion of available methods of contraception, especially long-term and permanent methods (LTPM). Aim To compare the uptake of contraceptive methods, and particularly LTPM, by HIV-positive and HIV-negative post-partum mothers, and to assess the effects of counselling on contraceptive choices. Setting Three government district hospitals in Swaziland. Methods Interviews were conducted using a structured questionnaire, before and after counselling HIV-negative and HIV-positive post-partum women in LTPM use, unintended pregnancy rates, future fertility and reasons for contraceptive choices. Results A total of 711 women, of whom half were HIV-positive, participated in the study. Most (72.3% HIV-negative and 84% HIV-positive) were on modern methods of contraception, with the majority using 2-monthly and 3-monthly injectables. Intended use of any contraceptive increased to 99% after counselling. LTPM use was 7.0% in HIV-negative mothers and 15.3% in HIV-positive mothers before counselling, compared with 41.3% and 42.4% in HIV-negative and HIV-positive mothers, respectively, after counselling. Pregnancy intentions and counselling on future fertility were significantly associated with current use of contraception, whilst current LTPM use and level of education were significantly associated with LTPM post-counselling. Conclusion Counselling on all methods including LTPM reduced unmet needs in contraception in HIV-positive and HIV-negative mothers and could improve contraceptive uptake and reduce unintended pregnancies. Health workers do not always remember to include LTPM when they counsel clients, which could result in a low uptake of these methods. Further experimental studies should be conducted to validate these results. PMID:26842525

Improved performance of graphene transistors by strain engineering.

PubMed

Nguyen, V Hung; Nguyen, Huy-Viet; Dollfus, P

2014-04-25

By means of numerical simulation, in this work we study the effects of uniaxial strain on the transport properties of strained graphene heterojunctions and explore the possibility of achieving good performance of graphene transistors using these hetero-channels. It is shown that a finite conduction gap can open in the strain junctions due to strain-induced deformation of the graphene bandstructure. These hetero-channels are then demonstrated to significantly improve the operation of graphene field-effect transistors (FETs). In particular, the ON/OFF current ratio can reach a value of over 10(5). In graphene normal FETs, the transconductance, although reduced compared to the case of unstrained devices, is still high, while good saturation of current can be obtained. This results in a high voltage gain and a high transition frequency of a few hundreds of GHz for a gate length of 80 nm. In graphene tunneling FETs, subthreshold swings lower than 30 mV /dec, strong nonlinear effects such as gate-controllable negative differential conductance, and current rectification are observed.

Extracting black-hole rotational energy: The generalized Penrose process

NASA Astrophysics Data System (ADS)

Lasota, J.-P.; Gourgoulhon, E.; Abramowicz, M.; Tchekhovskoy, A.; Narayan, R.

2014-01-01

In the case involving particles, the necessary and sufficient condition for the Penrose process to extract energy from a rotating black hole is absorption of particles with negative energies and angular momenta. No torque at the black-hole horizon occurs. In this article we consider the case of arbitrary fields or matter described by an unspecified, general energy-momentum tensor Tμν and show that the necessary and sufficient condition for extraction of a black hole's rotational energy is analogous to that in the mechanical Penrose process: absorption of negative energy and negative angular momentum. We also show that a necessary condition for the Penrose process to occur is for the Noether current (the conserved energy-momentum density vector) to be spacelike or past directed (timelike or null) on some part of the horizon. In the particle case, our general criterion for the occurrence of a Penrose process reproduces the standard result. In the case of relativistic jet-producing "magnetically arrested disks," we show that the negative energy and angular-momentum absorption condition is obeyed when the Blandford-Znajek mechanism is at work, and hence the high energy extraction efficiency up to ˜300% found in recent numerical simulations of such accretion flows results from tapping the black hole's rotational energy through the Penrose process. We show how black-hole rotational energy extraction works in this case by describing the Penrose process in terms of the Noether current.

Expanding on the relationship between continuing current and in-cloud leader growth

NASA Astrophysics Data System (ADS)

Lapierre, Jeff L.; Sonnenfeld, Richard G.; Stock, Michael; Krehbiel, Paul R.; Edens, Harald E.; Jensen, Daniel

2017-04-01

When lightning connects to the ground, there is a large surge of current, called the return stroke, which is occasionally followed by a longer-lasting steady current, called continuing current (CC). In a previous study of negative cloud-to-ground (-CG) flashes, we observed the growth rate of in-cloud positive leaders in an attempt to identify occurrences of CC. However, there was no observed change in positive leader growth rate during CC of negative CG flashes. In this study, we use the Langmuir Electric Field Array, Lightning Mapping Array, and Flash-Continuous Broadband Digital Interferometer data to extend the previous study to the growth of the negative leader during positive CG flashes. We have found that in contrast with previous results, negative leader growth during positive CG flashes does show increases in growth rates coincident with CC. Finally, we find that the growth rate magnitudes for positive and negative leaders are typically ˜2-4 km/10 ms and ˜25-40 km/10 ms, respectively. These contrasting results highlight the differences between positive and negative leaders and provide strong evidence as to why -CC and +CC behave differently. Negative leaders inject higher amounts of current and allow the channel to remain conductive throughout the duration of CC. Whereas for positive leaders, the channel becomes nonconductive relatively quickly. It is therefore disconnected from the channel to the ground, and, due to the positive leader's continued growth, an electric potential is built up until a K event is produced that re-ionizes the channel.

Symptom dimensions of affective disorders in migraine patients.

PubMed

Louter, M A; Pijpers, J A; Wardenaar, K J; van Zwet, E W; van Hemert, A M; Zitman, F G; Ferrari, M D; Penninx, B W; Terwindt, G M

2015-11-01

A strong association has been established between migraine and depression. However, this is the first study to differentiate in a large sample of migraine patients for symptom dimensions of the affective disorder spectrum. Migraine patients (n=3174) from the LUMINA (Leiden University Medical Centre Migraine Neuro-analysis Program) study and patients with current psychopathology (n=1129), past psychopathology (n=477), and healthy controls (n=561) from the NESDA (Netherlands Study of Depression and Anxiety) study, were compared for three symptom dimensions of depression and anxiety. The dimensions -lack of positive affect (depression specific); negative affect (nonspecific); and somatic arousal (anxiety specific)- were assessed by a shortened adaptation of the Mood and Anxiety Symptom Questionnaire (MASQ-D30). Within the migraine group, the association with migraine specific determinants was established. Multivariate regression analyses were conducted. Migraine patients differed significantly (p<0.001) from healthy controls for all three dimensions: Cohen's d effect sizes were 0.37 for lack of positive affect, 0.68 for negative affect, and 0.75 for somatic arousal. For the lack of positive affect and negative affect dimensions, migraine patients were predominantly similar to the past psychopathology group. For the somatic arousal dimension, migraine patients scores were more comparable with the current psychopathology group. Migraine specific determinants for high scores on all dimensions were high frequency of attacks and cutaneous allodynia during attacks. This study shows that affective symptoms in migraine patients are especially associated with the somatic arousal component. Copyright © 2015 Elsevier Inc. All rights reserved.

Electrochemical cell with high conductivity glass electrolyte

DOEpatents

Nelson, P.A.; Bloom, I.D.; Roche, M.F.

1986-04-17

A secondary electrochemical cell with sodium-sulfur or other molten reactants is provided with an ionically conductive glass electrolyte. The cell is contained within an electrically conductive housing with a first portion at negative potential and a second portion insulated therefrom at positive electrode potential. The glass electrolyte is formed into a plurality of elongated tubes and placed lengthwise within the housing. The positive electrode material, for instance sulfur, is sealed into the glass electrolyte tubes and is provided with an elongated axial current collector. The glass electrolyte tubes are protected by shield tubes or sheets that also define narrow annuli for wicking of the molten negative electrode material.

Electrochemical cell with high conductivity glass electrolyte

DOEpatents

Nelson, P.A.; Bloom, I.D.; Roche, M.F.

1987-04-21

A secondary electrochemical cell with sodium-sulfur or other molten reactants is provided with a ionically conductive glass electrolyte. The cell is contained within an electrically conductive housing with a first portion at negative potential and a second portion insulated therefrom at positive electrode potential. The glass electrolyte is formed into a plurality of elongated tubes and placed lengthwise within the housing. The positive electrode material, for instance sulfur, is sealed into the glass electrolyte tubes and is provided with an elongated axial current collector. The glass electrolyte tubes are protected by shield tubes or sheets that also define narrow annuli for wicking of the molten negative electrode material. 6 figs.

Electrochemical cell with high conductivity glass electrolyte

DOEpatents

Nelson, Paul A.; Bloom, Ira D.; Roche, Michael F.

1987-01-01

A secondary electrochemical cell with sodium-sulfur or other molten reactants is provided with a ionically conductive glass electrolyte. The cell is contained within an electrically conductive housing with a first portion at negative potential and a second portion insulated therefrom at positive electrode potential. The glass electrolyte is formed into a plurality of elongated tubes and placed lengthwise within the housing. The positive electrode material, for instance sulfur, is sealed into the glass electrolyte tubes and is provided with an elongated axial current collector. The glass electrolyte tubes are protected by shield tubes or sheets that also define narrow annuli for wicking of the molten negative electrode material.

Simulation of cesium injection and distribution in rf-driven ion sources for negative hydrogen ion generation.

PubMed

Gutser, R; Fantz, U; Wünderlich, D

2010-02-01

Cesium seeded sources for surface generated negative hydrogen ions are major components of neutral beam injection systems in future large-scale fusion experiments such as ITER. Stability and delivered current density depend highly on the cesium conditions during plasma-on and plasma-off phases of the ion source. The Monte Carlo code CSFLOW3D was used to study the transport of neutral and ionic cesium in both phases. Homogeneous and intense flows were obtained from two cesium sources in the expansion region of the ion source and from a dispenser array, which is located 10 cm in front of the converter surface.

Helicon wave-generated plasmas for negative ion beams for fusion

NASA Astrophysics Data System (ADS)

Furno, Ivo; Agnello, Riccardo; Fantz, U.; Howling, Alan; Jacquier, Remy; Marini, Claudio; Plyushchev, Gennady; Guittienne, Philippe; Simonin, Alain

2017-10-01

In the next generation of fusion reactors, such as DEMO, neutral beam injectors (NBIs) of high energy (0.8-1 MeV) deuterium atoms with high wall-plug efficiency (>50%) will be required to reach burning plasma conditions and to provide a significant amount of current drive. The present NBI system for DEMO assumes that 50 MW is delivered to the plasma by 3 NBIs. In the Siphore NBI concept, negative deuterium ions are extracted from a long, thin ion source 3 m high and 15 cm wide, accelerated and subsequently photo-neutralized. This requires the development of a new generation of negative ion sources. At the Swiss Plasma Center, a novel radio frequency helicon plasma source, based on a resonant network antenna source delivering up to 10 kW at 13.56 MHz, has been developed and is presently under study on the Resonant Antenna Ion Device (RAID). RAID is a linear device (1.9 m total length, 0.4 m diameter) and is equipped with an extensive set of diagnostics for full plasma characterization. In this work, the principles of operation of resonant antennas as helicon sources are introduced. We present absolute spectroscopy, Langmuir probe, and interferometry measurements on helicon plasmas. We characterize the performance of the source in terms of hydrogen/deuterium dissociation and negative ion production as a function of the input power. Furthermore, first results with the helicon birdcage antenna installed on the Cybele negative ion source at CEA-IRFM are presented, as a first step towards the validation of the Siphore concept.

All-carbon sp-sp2 hybrid structures: Geometrical properties, current rectification, and current amplification

PubMed Central

Zhang, Zhenhua; Zhang, Junjun; Kwong, Gordon; Li, Ji; Fan, Zhiqiang; Deng, Xiaoqing; Tang, Guiping

2013-01-01

All-carbon sp-sp2 hybrid structures comprised of a zigzag-edged trigonal graphene (ZTG)and carbon chains are proposed and constructed as nanojunctions. It has been found that such simple hybrid structures possess very intriguing propertiesapp:addword:intriguing. The high-performance rectifying behaviors similar to macroscopic p-n junction diodes, such as a nearly linear positive-bias I-V curve (metallic behavior), a very small leakage current under negative bias (insulating behavior), a rather low threshold voltage, and a large bias region contributed to a rectification, can be predicted. And also, a transistor can be built by such a hybrid structure, which can show an extremely high current amplification. This is because a sp-hybrid carbon chain has a special electronic structure which can limit the electronic resonant tunneling of the ZTG to a unique and favorable situation. These results suggest that these hybrid structures might promise importantly potential applications for developing nano-scale integrated circuits. PMID:23999318

Current instability and burnout of HEMT structures

NASA Astrophysics Data System (ADS)

Vashchenko, V. A.; Sinkevitch, V. F.

1996-06-01

The burnout mechanism and region of high conductivity formation under breakdown of pseudomorphic GalnAs/GaAlAs and GaAs/GaAlAs HEMT structures have been studied in a pulsed and direct current (d.c.) regime. Peculiarities of the HEMT breakdown have been compared with a GaAs MESFET structure of the same topology. It appears that in all types of investigated structures the drain voltage increase is limited by the transition into a high conductivity state as a result of "parasitic" avalanche-injection conductivity modulation of the undoped GaAs or i-GaAs layer. It has been established that the transition into a high conductivity state is caused by holes from the drain avalanche region in the channel and is the result of a mutual intensification of the avalanche generation rate near the drain and the injection level from the source contact. It turns out that under a typical gate bias operation the transition in the high conductivity state is accompanied by a negative differential conductivity (NDC) and results in the formation of high current density filaments. The resulting high local overheating in the filament region is the cause of local melting and burnout of the HEMT structures.

Social interaction and social withdrawal in rodents as readouts for investigating the negative symptoms of schizophrenia

PubMed Central

Wilson, Christina A.; Koenig, James I.

2015-01-01

Negative symptoms (e.g., asociality and anhedonia) are a distinct symptomatic domain that has been found to significantly affect the quality of life in patients diagnosed with schizophrenia. Additionally, the primary negative symptom of asociality (i.e., withdrawal from social contact that derives from indifference or lack of desire to have social contact) is a major contributor to poor psychosocial functioning and has been found to play an important role in the course of the disorder. Nonetheless, the pathophysiology underlying these symptoms is unknown and currently available treatment options (e.g., antipsychotics and cognitive-behavioral therapy) fail to reliably produce efficacious benefits. Utilizing rodent paradigms that measure social behaviors (e.g., social withdrawal) to elucidate the neurobiological substrates that underlie social dysfunction and to identify novel therapeutic targets may be highly informative and useful to understand more about the negative symptoms of schizophrenia. Accordingly, the purpose of this review is to provide an overview of the behavioral tasks for assessing social functioning that may be translationally relevant for investigating negative symptoms associated with schizophrenia. PMID:24342774

Social interaction and social withdrawal in rodents as readouts for investigating the negative symptoms of schizophrenia.

PubMed

Wilson, Christina A; Koenig, James I

2014-05-01

Negative symptoms (e.g., asociality and anhedonia) are a distinct symptomatic domain that has been found to significantly affect the quality of life in patients diagnosed with schizophrenia. Additionally, the primary negative symptom of asociality (i.e., withdrawal from social contact that derives from indifference or lack of desire to have social contact) is a major contributor to poor psychosocial functioning and has been found to play an important role in the course of the disorder. Nonetheless, the pathophysiology underlying these symptoms is unknown and currently available treatment options (e.g., antipsychotics and cognitive-behavioral therapy) fail to reliably produce efficacious benefits. Utilizing rodent paradigms that measure social behaviors (e.g., social withdrawal) to elucidate the neurobiological substrates that underlie social dysfunction and to identify novel therapeutic targets may be highly informative and useful to understand more about the negative symptoms of schizophrenia. Accordingly, the purpose of this review is to provide an overview of the behavioral tasks for assessing social functioning that may be translationally relevant for investigating negative symptoms associated with schizophrenia. © 2013 Published by Elsevier B.V. and ECNP.

The Conductor-Dielectric Junctions in a Low Density Plasma

NASA Technical Reports Server (NTRS)

Vayner, Boris; Galofaro, Joel; Ferguson, Dale; deGroot, Wim; Thomson, Clint; Dennison, J. R.; Davies, Robert

1999-01-01

A conductor-dielectric junction exposed to the space environment is a frequent spacecraft design feature. Due to spacecraft charging and/or solar array operation, the conductor can acquire a high potential with respect to the surrounding plasma. If this potential is positive the insulators adjacent to exposed conductors can collect current as if they were conductors themselves. This phenomenon, called snapover, results in a substantial increase in current collection, and may even result in a glow discharge if the potential is high enough. If a conductor has a negative potential, arcing can occur at the site of a junction. Both of these phenomena negatively affect spacecraft operation. To prevent negative consequences, the physical mechanisms of snapover and arc inception require investigation. In this paper, results are presented of an experimental and theoretical study of snapover, glow discharge, and arc phenomena for different materials immersed in argon or xenon plasmas. The effect of snapover is investigated for several metal-dielectric junctions: copper-teflon, copper-Kapton, copper-glass, aluminum-teflon, aluminum-Kapton, steel-teflon, anodized aluminum with pinholes, and copper-ceramics. I-V curves are measured and snapover inception voltages, essential parameters (increase in current and collection area due to secondary electrons), and glow discharge inception thresholds are determined. Optical spectra are obtained for glow discharges in both argon and xenon plasmas. These spectra provide information regarding atomic species entrapped in the glow region. Some spectral lines can be used to estimate plasma parameters in the discharge area. A video-camera and linear array were used to confirm that snapover inception is accompanied by very low intensity visible light emission. This result seems to be important for the estimate of the light pollution around spacecraft. Optical spectra (wavelengths 380-650 nm) of arcs are also obtained on a negatively biased chromic acid anodized aluminum plate immersed in low density argon and xenon plasmas. Analysis of these spectra confirms our earlier findings that aluminum atoms are ejected from the arc site. Moreover, it is found that chromium atoms are also quite abundant in the arc plasma. It is believed that the latter results contribute considerably to the understanding of processes of plasma contamination caused by arcing.

Costs on the Mind: the Influence of the Financial Burden of College on Academic Performance and Cognitive Functioning

ERIC Educational Resources Information Center

Destin, Mesmin; Svoboda, Ryan C.

2018-01-01

The current studies test the hypothesis that the financial burden of college can initiate a psychological process that has a negative influence on academic performance for students at selective colleges and universities. Prior studies linking high college costs and student loans to academic outcomes have not been grounded within relevant social…

Personality Predispositions to Depression in Children of Affectively-Ill Parents: The Buffering Role of Self-Esteem

ERIC Educational Resources Information Center

Abela, John R. Z.; Fishman, Michael B.; Cohen, Joseph R.; Young, Jami F.

2012-01-01

A major theory of personality predispositions to depression posits that individuals who possess high levels of self-criticism and/or dependency are vulnerable to developing depression following negative life events. The goal of the current study was to test this theory of personality predispositions and the self-esteem buffering hypothesis in a…

Variable-frequency inverter controls torque, speed, and braking in ac induction motors

NASA Technical Reports Server (NTRS)

Nola, F. J.

1974-01-01

Dc to ac inverter provides optimum frequency and voltage to ac induction motor, in response to different motor-load and speed requirements. Inverter varies slip frequency of motor in proportion to required torque. Inverter protects motor from high current surges, controls negative slip to apply braking, and returns energy stored in momentum of load to dc power source.

Hemispheric processing of predictive inferences during reading: The influence of negatively emotional valenced stimuli.

PubMed

Virtue, Sandra; Schutzenhofer, Michael; Tomkins, Blaine

2017-07-01

Although a left hemisphere advantage is usually evident during language processing, the right hemisphere is highly involved during the processing of weakly constrained inferences. However, currently little is known about how the emotional valence of environmental stimuli influences the hemispheric processing of these inferences. In the current study, participants read texts promoting either strongly or weakly constrained predictive inferences and performed a lexical decision task to inference-related targets presented to the left visual field-right hemisphere or the right visual field-left hemisphere. While reading these texts, participants either listened to dissonant music (i.e., the music condition) or did not listen to music (i.e., the no music condition). In the no music condition, the left hemisphere showed an advantage for strongly constrained inferences compared to weakly constrained inferences, whereas the right hemisphere showed high facilitation for both strongly and weakly constrained inferences. In the music condition, both hemispheres showed greater facilitation for strongly constrained inferences than for weakly constrained inferences. These results suggest that negatively valenced stimuli (such as dissonant music) selectively influences the right hemisphere's processing of weakly constrained inferences during reading.

Discrete emotion-congruent false memories in the DRM paradigm.

PubMed

Bland, Cassandra E; Howe, Mark L; Knott, Lauren

2016-08-01

Research has shown that false-memory production is enhanced for material that is emotionally congruent with the mood of the participant at the time of encoding. So far this research has only been conducted to examine the influence of generic negative affective mood states and generic negative stimuli on false-memory production. In addition, much of the research is limited as it focuses on valence and arousal dimensions, and fails to take into account the more comprehensive nature of emotions. The current study demonstrates that this effect goes beyond general negative or positive moods and acts at a more discrete emotional level. Participants underwent a standard emotion-induction procedure before listening to negative emotional or neutral associative word lists. The emotions induced, negative word lists, and associated nonpresented critical lures, were related to either fear or anger, 2 negative valence emotions that are also both high in arousal. Results showed that when valence and arousal are controlled for, false memories are more likely to be produced for discrete emotionally congruent compared with incongruent materials. These results support spreading activation theories of false remembering and add to our understanding of the adaptive nature of false-memory production. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Negative electrodes for Na-ion batteries.

PubMed

Dahbi, Mouad; Yabuuchi, Naoaki; Kubota, Kei; Tokiwa, Kazuyasu; Komaba, Shinichi

2014-08-07

Research interest in Na-ion batteries has increased rapidly because of the environmental friendliness of sodium compared to lithium. Throughout this Perspective paper, we report and review recent scientific advances in the field of negative electrode materials used for Na-ion batteries. This paper sheds light on negative electrode materials for Na-ion batteries: carbonaceous materials, oxides/phosphates (as sodium insertion materials), sodium alloy/compounds and so on. These electrode materials have different reaction mechanisms for electrochemical sodiation/desodiation processes. Moreover, not only sodiation-active materials but also binders, current collectors, electrolytes and electrode/electrolyte interphase and its stabilization are essential for long cycle life Na-ion batteries. This paper also addresses the prospect of Na-ion batteries as low-cost and long-life batteries with relatively high-energy density as their potential competitive edge over the commercialized Li-ion batteries.

Perceptions of affectionate communication among people with unfavorable and favorable attitudes toward homosexuality.

PubMed

Brantley-Hill, Stacia M; Brinthaupt, Thomas M

2014-01-01

People are sometimes hesitant to communicate affection if it might be misinterpreted by the intended receiver or an audience. We hypothesized that anti-gay/-lesbian attitudes might negatively affect the perceived appropriateness of expressing affection. One hundred and twenty male and female undergraduates with either very high or very low levels of anti-gay/-lesbian attitudes participated in the study. They rated the appropriateness of expressing affection toward same- and other-sex targets in a set of 2 (public or private setting) × 3 (positive, neutral, or negative valence) scenarios. Results supported a "generalized inhibition" effect, with high levels of anti-gay/-lesbian attitudes associated with a reluctance to express affection regardless of target, setting, valence, or current relationship status. Implications for research on affectionate expression and anti-gay/-lesbian attitudes are presented.

An examination of factors driving chinese gamblers' fallacy bias.

PubMed

Fong, Lawrence Hoc Nang; Law, Rob; Lam, Desmond

2014-09-01

Gambling is a leisure activity, which is enjoyed by many people around the world. Among these people, Chinese are known for their high propensity to gamble and are highly sought after by many casinos. In this exploratory study, the effect of two types of fallacy bias-positive recency and negative recency-on the betting behavior of Chinese gamblers is investigated. Although the influence of fallacy bias on a betting decision is well documented, little is known about the interaction of the factors that dictate fallacy bias. Drawing from an analysis of 2,645 betting decisions, the results show that Chinese gamblers primarily endorse positive recency, especially when the latest outcome is more frequent. This is contrary to most findings on Western subjects in which negative recency is more common. Current findings have meaningful implications to casino gaming entertainment businesses and public policymakers.

Recent advances in plasma devices based on plasma lens configuration for manipulating high-current heavy ion beams.

PubMed

Dobrovolskiy, A; Dunets, S; Evsyukov, A; Goncharov, A; Gushenets, V; Litovko, I; Oks, E

2010-02-01

We describe new results of development of novel generation cylindrical plasma devices based on the electrostatic plasma lens configuration and concept of electrons magnetic insulation. The crossed electric and magnetic fields plasma lens configuration provides us with the attractive and suitable method for establishing a stable plasma discharge at low pressure. Using plasma lens configuration in this way some cost-effective plasma devices were developed for ion treatment and deposition of exotic coatings and the effective lens was first proposed for manipulating high-current beams of negatively charged particles. Here we describe operation and features of these plasma devices, and results of theoretical consideration of mechanisms determining their optimal operation conditions.

Toward the next generation of negative symptom assessments: the collaboration to advance negative symptom assessment in schizophrenia.

PubMed

Blanchard, Jack J; Kring, Ann M; Horan, William P; Gur, Raquel

2011-03-01

Negative symptoms in schizophrenia are related to poor functional outcome, persistent over time, a source of burden for caregivers, and only minimally responsive to currently available medications. A major challenge to developing efficacious interventions concerns the valid and reliable assessment of negative symptoms. In a recent consensus statement on negative symptoms, a central recommendation was the need to develop new assessment approaches that address the limitations of existing instruments. In the current report, we summarize the background and rationale for the Collaboration to Advance Negative Symptom Assessment in Schizophrenia (CANSAS). The CANSAS project is an National Institute of Mental Health-funded multisite study that is constructing a next-generation negative symptom scale, the Clinical Assessment Interview for Negative Symptoms (CAINS). The CAINS is being developed within a data-driven iterative process that seeks to ensure the measure's reliability, validity, and utility for both basic psychopathology and treatment development research.

Multi-species genetic connectivity in a terrestrial habitat network.

PubMed

Marrotte, Robby R; Bowman, Jeff; Brown, Michael G C; Cordes, Chad; Morris, Kimberley Y; Prentice, Melanie B; Wilson, Paul J

2017-01-01

Habitat fragmentation reduces genetic connectivity for multiple species, yet conservation efforts tend to rely heavily on single-species connectivity estimates to inform land-use planning. Such conservation activities may benefit from multi-species connectivity estimates, which provide a simple and practical means to mitigate the effects of habitat fragmentation for a larger number of species. To test the validity of a multi-species connectivity model, we used neutral microsatellite genetic datasets of Canada lynx ( Lynx canadensis ), American marten ( Martes americana ), fisher ( Pekania pennanti ), and southern flying squirrel ( Glaucomys volans ) to evaluate multi-species genetic connectivity across Ontario, Canada. We used linear models to compare node-based estimates of genetic connectivity for each species to point-based estimates of landscape connectivity (current density) derived from circuit theory. To our knowledge, we are the first to evaluate current density as a measure of genetic connectivity. Our results depended on landscape context: habitat amount was more important than current density in explaining multi-species genetic connectivity in the northern part of our study area, where habitat was abundant and fragmentation was low. In the south however, where fragmentation was prevalent, genetic connectivity was correlated with current density. Contrary to our expectations however, locations with a high probability of movement as reflected by high current density were negatively associated with gene flow. Subsequent analyses of circuit theory outputs showed that high current density was also associated with high effective resistance, underscoring that the presence of pinch points is not necessarily indicative of gene flow. Overall, our study appears to provide support for the hypothesis that landscape pattern is important when habitat amount is low. We also conclude that while current density is proportional to the probability of movement per unit area, this does not imply increased gene flow, since high current density tends to be a result of neighbouring pixels with high cost of movement (e.g., low habitat amount). In other words, pinch points with high current density appear to constrict gene flow.

Superconductive microstrip exhibiting negative differential resistivity

DOEpatents

Huebener, R.P.; Gallus, D.E.

1975-10-28

A device capable of exhibiting negative differential electrical resistivity over a range of values of current and voltage is formed by vapor- depositing a thin layer of a material capable of exhibiting superconductivity on an insulating substrate, establishing electrical connections at opposite ends of the deposited strip, and cooling the alloy into its superconducting range. The device will exhibit negative differential resistivity when biased in the current- induced resistive state.

Numerical analysis on the synergy between electron cyclotron current drive and lower hybrid current drive in tokamak plasmas

NASA Astrophysics Data System (ADS)

Chen, S. Y.; Hong, B. B.; Liu, Y.; Lu, W.; Huang, J.; Tang, C. J.; Ding, X. T.; Zhang, X. J.; Hu, Y. J.

2012-11-01

The synergy between electron cyclotron current drive (ECCD) and lower hybrid current drive (LHCD) is investigated numerically with the parameters of the HL-2A tokamak. Based on the understanding of the synergy mechanisms, a high current driven efficiency or a desired radial current profile can be achieved through properly matching the parameters of ECCD and LHCD due to the flexibility of ECCD. Meanwhile, it is found that the total current driven by the electron cyclotron wave (ECW) and the lower hybrid wave (LHW) simultaneously can be smaller than the sum of the currents driven by the ECW and LHW separately, when the power of the ECW is much larger than the LHW power. One of the reasons leading to this phenomenon (referred to as negative synergy in this context) is that fast current-carrying electrons tend to be trapped, when the perpendicular velocity driven by the ECW is large and the parallel velocity decided by the LHW is correspondingly small.

Baseline social amotivation predicts 1-year functioning in UHR subjects: A validation and prospective investigation.

PubMed

Lam, Max; Abdul Rashid, Nur Amirah; Lee, Sara-Ann; Lim, Jeanette; Foussias, George; Fervaha, Gagan; Ruhrman, Stephan; Remington, Gary; Lee, Jimmy

2015-12-01

Social amotivation and diminished expression have been reported to underlie negative symptomatology in schizophrenia. In the current study we sought to establish and validate these negative symptom domains in a large cohort of schizophrenia subjects (n=887) and individuals who are deemed to be Ultra-High Risk (UHR) for psychosis. Confirmatory factor analysis conducted on PANSS item domains demonstrate that the dual negative symptom domains exist in schizophrenia and UHR subjects. We further sought to examine if these negative symptom domains were associated with functioning in UHR subjects. Linear regression analyses confirmed that social amotivation predicted functioning in UHR subjects prospectively at 1 year follow up. Results suggest that the association between social amotivation and functioning is generalisable beyond schizophrenia populations to those who are at-risk of developing psychosis. Social amotivation may be an important dimensional clinical construct to be studied across a range of psychiatric conditions. Copyright © 2015 Elsevier B.V. and ECNP. All rights reserved.

Self-verification and depression among youth psychiatric inpatients.

PubMed

Joiner, T E; Katz, J; Lew, A S

1997-11-01

According to self-verification theory (e.g., W.B. Swann, 1983), people are motivated to preserve stable self-concepts by seeking self-confirming interpersonal responses, even if the responses are negative. In the current study of 72 youth psychiatric inpatients (36 boys; 36 girls; ages 7-17, M = 13.18; SD = 2.59), the authors provide the 1st test of self-verification theory among a youth sample. Participants completed self-report questionnaires on depression, self-esteem, anxiety, negative and positive affect, and interest in negative feedback from others. The authors made chart diagnoses available, and they collected peer rejection ratings. Consistent with hypotheses, the authors found that interest in negative feedback was associated with depression, was predictive of peer rejection (but only within relatively longer peer relationships), was more highly related to cognitive than emotional aspects of depression, and was specifically associated with depression, rather than being generally associated with emotional distress. The authors discuss implications for self-verification theory and for the phenomenology of youth depression.

The Growing Threat of Multidrug-Resistant Gram-Negative Infections in Patients with Hematologic Malignancies

PubMed Central

Baker, Thomas M.; Satlin, Michael J.

2016-01-01

Prolonged neutropenia and chemotherapy-induced mucositis render patients with hematologic malignancies highly vulnerable to Gram-negative bacteremia. Unfortunately, multidrug-resistant (MDR) Gram-negative bacteria are increasingly encountered globally, and current guidelines for empirical antibiotic coverage in these patients may not adequately treat these bacteria. This expansion of resistance, coupled with traditional culturing techniques requiring 2-4 days for bacterial identification and antimicrobial susceptibility results, have grave implications for these immunocompromised hosts. This review characterizes the epidemiology, risk factors, resistance mechanisms, recommended treatments, and outcomes of the MDR Gram-negative bacteria that commonly cause infections in patients with hematologic malignancies. We also examine infection prevention strategies in hematology patients, such as infection control practices, antimicrobial stewardship, and targeted decolonization. Finally, we assess strategies to improve outcomes of infected patients, including gastrointestinal screening to guide empirical antibiotic therapy, new rapid diagnostic tools for expeditious identification of MDR pathogens, and use of two new antimicrobial agents, ceftolozane/tazobactam and ceftazidime/avibactam. PMID:27339405

Financial strain and cognitive-based smoking processes: The explanatory role of depressive symptoms among adult daily smokers.

PubMed

Robles, Zuzuky; Anjum, Sahar; Garey, Lorra; Kauffman, Brooke Y; Rodríguez-Cano, Rubén; Langdon, Kirsten J; Neighbors, Clayton; Reitzel, Lorraine R; Zvolensky, Michael J

2017-07-01

Little work has focused on the underlying mechanisms that may link financial strain and smoking processes. The current study tested the hypothesis that financial strain would exert an indirect effect on cognitive-based smoking processes via depressive symptoms. Three clinically significant dependent variables linked to the maintenance of smoking were evaluated: negative affect reduction motives, negative mood abstinence expectancies, and perceived barriers for quitting. Participants included 102 adult daily smokers (M age =33.0years, SD=13.60; 35.3% female) recruited from the community to participate in a self-guided (unaided; no psychological or pharmacological intervention) smoking cessation study. Results indicated that depressive symptoms explain, in part, the relation between financial strain and smoking motives for negative affect reduction, negative mood abstinence expectancies, and perceived barriers for quitting. Results indicate that smoking interventions for individuals with high levels of financial strain may potentially benefit from the addition of therapeutic tactics aimed at reducing depression. Copyright © 2017 Elsevier Ltd. All rights reserved.

A closer look at the relationship between the default network, mind wandering, negative mood, and depression.

PubMed

Konjedi, Shaghayegh; Maleeh, Reza

2017-08-01

By a systematic analysis of the current literature on the neural correlates of mind wandering, that is, the default network (DN), and by shedding light on some determinative factors and conditions which affect the relationship between mind wandering and negative mood, we show that (1) mind wandering per se does not necessarily have a positive correlation with negative mood and, on the higher levels, depression. We propose that negative mood as a consequence of mind wandering generally depends on two determinative conditions, that is, whether mind wandering is with or without meta-awareness and whether mind wandering occurs during high or low vigilance states; (2) increased activity of the DN is not necessarily followed by an increase in unhappiness and depression. We argue that while in some kinds of meditation practices we witness an increase in the structure and in the activity of the DN, no increase in unhappiness and depression is observed.

Current Reversals of an Underdamped Brownian Particle in an Asymmetric Deformable Potential

NASA Astrophysics Data System (ADS)

Cai, Chun-Chun; Liu, Jian-Li; Chen, Hao; Li, Feng-Guo

2018-03-01

Transport of an underdamped Brownian particle in a one-dimensional asymmetric deformable potential is investigated in the presence of both an ac force and a static force, respectively. From numerical simulations, we obtain the current average velocity. The current reversals and the absolute negative mobility are presented. The increasing of the deformation of the potential can cause the absolute negative mobility to be suppressed and even disappear. When the static force is small, the increase of the potential deformation suppresses the absolute negative mobility. When the force is large, the absolute negative mobility disappears. In particular, when the potential deformation is equal to 0.015, the two current reversals present with the increasing of the force. Remarkably, when the potential deformation is small, there are three current reversals with the increasing of the friction coefficient and the average velocity presents a oscillation behavior. Supported in part by the National Natural Science Foundation of China under Grant Nos. 11575064 and 11175067, and the Natural Science Foundation of Guangdong Province under Grant No. 2016A030313433

Review of terahertz semiconductor sources

NASA Astrophysics Data System (ADS)

Wei, Feng

2012-03-01

Terahertz (THz) technology can be used in information science, biology, medicine, astronomy, and environmental science. THz sources are the key devices in THz applications. The author gives a brief review of THz semiconductor sources, such as GaAs1-xNx Gunn-like diodes, quantum wells (QWs) negative-effective-mass (NEM) THz oscillators, and the THz quantum cascade lasers (QCLs). THz current self-oscillation in doped GaAs1-xNx diodes driven by a DC electric field was investigated. The current self-oscillation is associated with the negative differential velocity effect in the highly nonparabolic conduction band of this unique material system. The current self-oscillations and spatiotemporal current patterns in QW NEM p+pp+ diodes was studied by considering scattering contributions from impurities, acoustic phonons, and optic phonons. It is indicated that both the applied bias and the doping concentration strongly influence the patterns and self-oscillating frequencies. The NEM p+pp+ diode may be used as an electrically tunable THz source. Meanwhile, by using the Monte Carlo method, the device parameters of resonant-phonon THz QCLs were optimized. The results show that the calculated gain is more sensitive to the injection barrier width, the doping concentration, and the phonon extraction level separation, which is consistent with the experiments.

The relationship between religion and thought-action fusion: use of an in vivo paradigm.

PubMed

Berman, Noah C; Abramowitz, Jonathan S; Pardue, Caleb M; Wheaton, Michael G

2010-07-01

Research has demonstrated that higher levels of religiosity are positively correlated with thought-action fusion (TAF), a set of cognitive biases found to be associated with obsessive-compulsive symptoms. However, previous studies have exclusively relied on a nomothetic approach to measuring TAF using a single self-report instrument, the thought-action fusion scale. The current study examined the relationship between religiosity and TAF using an in vivo behaviorally-based assessment in which participants thought about and wrote down thoughts of negative events involving loved ones. Forty-three highly religious Protestant Christians were compared to 30 Atheists/Agnostics on their in vivo ratings of anxiety, estimates of likelihood, and moral wrongness related to the negative thoughts. Results indicated that compared to the non-religious participants, those who were highly religious believed that writing and thinking about the negative events was more morally wrong and increased the likelihood of the event. Results are discussed in terms of the potential relationship between certain religious teachings and TAF-related beliefs about the importance, significance, and influence of thoughts. Copyright 2010 Elsevier Ltd. All rights reserved.

Adolescents' response to parental efforts to influence eating habits: when parental warmth matters.

PubMed

Lessard, Jared; Greenberger, Ellen; Chen, Chuansheng

2010-01-01

Previous findings have shown both beneficial and adverse effects of parents' attempts to influence adolescents' eating habits. The current study examined the differential effect of parents' persuasion (e.g., encouragement, giving information) and pressure tactics (e.g., guilt induction, ridicule) and the moderating influence of parental warmth on older adolescents' emotional and behavioral responses. An ethnically diverse sample of 336 older adolescents (M age = 18.6; SD = 1.1; 58.0% female) were surveyed. Adolescents who reported higher levels of pressure tactics by parents reported more negative affect and behavioral resistance. Perceived parental warmth moderated the influence of persuasion tactics, but not pressure tactics. For adolescents with low parental warmth, high levels of persuasion were associated with more negative emotional and behavioral responses; persuasion had the opposite associations for adolescents with high parental warmth. These results suggest that parental warmth plays an important role in how older adolescents respond to parents' persuasion tactics. However, when parents use more forceful pressure tactics to influence eating habits, adolescents react negatively regardless of the overall quality of the parent-adolescent relationship.

Expressive Suppression Tendencies, Projection Bias in Memory of Negative Emotions, and Well-Being.

PubMed

Chang, Valerie T; Overall, Nickola C; Madden, Helen; Low, Rachel S T

2018-02-01

The current research extends prior research linking negative emotions and emotion regulation tendencies to memory by investigating whether (a) naturally occurring negative emotions during routine weekly life are associated with more negatively biased memories of prior emotional experiences-a bias called projection; (b) tendencies to regulate emotions via expressive suppression are associated with greater projection bias in memory of negative emotions; and (c) greater projection bias in memory is associated with poorer future well-being. Participants (N = 308) completed a questionnaire assessing their general tendencies to engage in expressive suppression. Then, every week for 7 weeks, participants reported on (a) the negative emotions they experienced across the current week (e.g., "This week, I felt 'sad'"), (b) their memories of the negative emotions they experienced the prior week (e.g., "Last week, I felt 'sad'"), and (c) their well-being. First, participants demonstrated significant projection bias in memory: Greater negative emotions in a given week were associated with remembering emotions in the prior week more negatively than those prior emotions were originally reported. Second, projection bias in memory of negative emotions was greater for individuals who reported greater tendencies to regulate emotions via expressive suppression. Third, greater projection bias in memory of negative emotions was associated with reductions in well-being across weeks. These 3 novel findings indicate that (a) current negative emotions bias memory of past emotions, (b) this memory bias is magnified for people who habitually use expressive suppression to regulate emotions, and (c) this memory bias may undermine well-being over time. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Measuring the emergence of tobacco dependence: the contribution of negative reinforcement models.

PubMed

Eissenberg, Thomas

2004-06-01

This review of negative reinforcement models of drug dependence is part of a series that takes the position that a complete understanding of current concepts of dependence will facilitate the development of reliable and valid measures of the emergence of tobacco dependence. Other reviews within the series consider models that emphasize positive reinforcement and social learning/cognitive models. This review summarizes negative reinforcement in general and then presents four current negative reinforcement models that emphasize withdrawal, classical conditioning, self-medication and opponent-processes. For each model, the paper outlines central aspects of dependence, conceptualization of dependence development and influences that the model might have on current and future measures of dependence. Understanding how drug dependence develops will be an important part of future successful tobacco dependence measurement, prevention and treatment strategies.

Negative ion treatment increases positive emotional processing in seasonal affective disorder.

PubMed

Harmer, C J; Charles, M; McTavish, S; Favaron, E; Cowen, P J

2012-08-01

Antidepressant drug treatments increase the processing of positive compared to negative affective information early in treatment. Such effects have been hypothesized to play a key role in the development of later therapeutic responses to treatment. However, it is unknown whether these effects are a common mechanism of action for different treatment modalities. High-density negative ion (HDNI) treatment is an environmental manipulation that has efficacy in randomized clinical trials in seasonal affective disorder (SAD). The current study investigated whether a single session of HDNI treatment could reverse negative affective biases seen in seasonal depression using a battery of emotional processing tasks in a double-blind, placebo-controlled randomized study. Under placebo conditions, participants with seasonal mood disturbance showed reduced recognition of happy facial expressions, increased recognition memory for negative personality characteristics and increased vigilance to masked presentation of negative words in a dot-probe task compared to matched healthy controls. Negative ion treatment increased the recognition of positive compared to negative facial expression and improved vigilance to unmasked stimuli across participants with seasonal depression and healthy controls. Negative ion treatment also improved recognition memory for positive information in the SAD group alone. These effects were seen in the absence of changes in subjective state or mood. These results are consistent with the hypothesis that early change in emotional processing may be an important mechanism for treatment action in depression and suggest that these effects are also apparent with negative ion treatment in seasonal depression.

Evidence of negative leaders which precede fast rise ICC pulses of upward

NASA Astrophysics Data System (ADS)

Yoshida, S.; Akita, M.; Morimoto, T.; Ushio, T.; Kawasaki, Z.; Wang, D.; Takagi, N.

2008-12-01

During winter thunderstorm season in Japan, a lightning observation campaign was conducted with using a VHF broadband digital interferometer (DITF), a capacitive antenna, and Rogowski coils to study the charge transfer mechanism associated with ICC pulses of upward lightning. All the detection systems recorded one upward negative lightning stroke hitting a lightning protection tower. The upward lightning consists of only the Initial Stage (IS) with one upward positive leader and six ICC pulses. The six ICC pulses are sub-classified clearly into two types according to current pulse shapes. The type 1 ICC pulses have a higher geometric mean (GM) current peak of 17 kA and a shorter GM 10-90% risetime of 8.9 μs, while the type 2 ICC pulses have a lower GM current peak of 0.34 kA and longer GM 10-90% risetime of 55 μs. The type 1 ICC pulses have the preceding negative leaders connecting to the channel of the continuing current, while the type 2 ICC pulses have no clear preceding negative leader. These negative leaders prior to the type 1 ICC pulses probably caused the current increases of the ICC pulses, which means that the negative leaders created the channels for the ICC pulses. The height of the space charge transferred by one of the type 1 ICC pulses was estimated about 700 m above sea level at most. This observation result is the first evidence to show explicitly the existence of the negative leaders prior to the fast rise ICC pulse. Furthermore, the result shows that space charge could exist at a low attitude such as 700 m above sea level. This fact is one of the reasons why upward lightning occurs even from rather low structures during winter thunderstorm season in Japan.

The discovery of the sub-threshold currents M and Q/H in central neurons.

PubMed

Adams, Paul

2016-08-15

The history, content and consequences of the highly-cited 1982 Brain Research paper by Halliwell and Adams are summarized. The paper pioneered the use of the single-electrode voltage clamp in mammalian brain slices, described 2 novel sub-threshold voltage-dependent ionic currents, IM and IQ/H, and suggested that cholinergic inputs "enabled" pyramidal cell firing in response to conventional synaptic input, the first example of central neuromodulation. The paper, published in Brain Research to give the first author appropriate importance, heralded an ongoing tidal wave of quantitative electrophysiology in mammalian central neurons. Voltage-clamp analysis of muscarinic excitation in hippocampal neurons Pyramidal cells in the CA1 field of guinea pig hippocampal slices were voltage-clamped using a single microelectrode, at 23-30°C. Small inwardly relaxing currents triggered by step hyperpolarizations from holding potentials of -80 to -40mV were investigated. Inward relaxations occurring for negative steps between -40mV and -70mV resembled M-currents of sympathetic ganglion cells: they were abolished by addition of carbachol, muscarine or bethanechol, as well as by 1mM barium; the relaxations appeared to invert at around -80mV; they became faster at more negative potentials; and the inversion potential was shifted positively by raising external K(+) concentration. Inward relaxations triggered by steps negative to -80mV, in contrast, appeared to reflect passage of another current species, which has been labeled IQ.Thus IQ did not invert negative to -80mV, it was insensitive to muscarinic agonizts or to barium, and it was blocked by 0.5-3mM cesium (which does not block IM). Turn-on of IQ causes the well known droop in the hyperpolarizing electrotonic potential in these cells. The combined effects of IQ and IM make the steady-state current-voltage relation of CA1 cells slightly sigmoidal around rest potential. It is suggested that activation of cholinergic septal inputs to the hippocampus facilitates repetitive firing off pyramidal cells by turning off the M-conductance, without much change in the resting potential of the cell. © 1982. This article is part of a Special Issue entitled SI:50th Anniversary Issue. Copyright © 2016. Published by Elsevier B.V.

Cerebrospinal fluid dissemination of high-grade gliomas following boron neutron capture therapy occurs more frequently in the small cell subtype of IDH1R132H mutation-negative glioblastoma

PubMed Central

Barth, Rolf F.; Miyatake, Shin-Ichi; Kawabata, Shinji; Suzuki, Minoru; Ono, Koji

2017-01-01

We have used boron neutron capture therapy (BNCT) to treat patients in Japan with newly diagnosed or recurrent high-grade gliomas and have observed a significant increase in median survival time following BNCT. Although cerebrospinal fluid dissemination (CSFD) is not usually seen with the current standard therapy of patients with glioblastoma (GBM), here we report that subarachnoid or intraventricular CSFD was the most frequent cause of death for a cohort of our patients with high-grade gliomas who had been treated with BNCT. The study population consisted of 87 patients with supratentorial high-grade gliomas; 41 had newly diagnosed tumors and 46 had recurrent tumors. Thirty of 87 patients who were treated between January 2002 and July 2013 developed CSFD. Tumor histology before BNCT and immunohistochemical staining for two molecular markers, Ki-67 and IDH1R132H, were evaluated for 20 of the 30 patients for whom pathology slides were available. Fluorescence in situ hybridization (FISH) was performed on 3 IDH1R132H-positive and 1 control IDH1R132H-negative tumors in order to determine chromosome 1p and 19q status. Histopathologic evaluation revealed that 10 of the 20 patients’ tumors were IDH1R132H-negative small cell GBMs. The remaining patients had tumors consisting of other IDH1R132H-negative GBM variants, an IDH1R132H-positive GBM and two anaplastic oligodendrogliomas. Ki-67 immunopositivity ranged from 2 to 75%. In summary, IDH1R132H-negative GBMs, especially small cell GBMs, accounted for a disproportionately large number of patients who had CSF dissemination. This suggests that these tumor types had an increased propensity to disseminate via the CSF following BNCT and that these patients are at high risk for this clinically serious event. PMID:28534152

Cerebrospinal fluid dissemination of high-grade gliomas following boron neutron capture therapy occurs more frequently in the small cell subtype of IDH1R132H mutation-negative glioblastoma.

PubMed

Kondo, Natsuko; Barth, Rolf F; Miyatake, Shin-Ichi; Kawabata, Shinji; Suzuki, Minoru; Ono, Koji; Lehman, Norman L

2017-05-01

We have used boron neutron capture therapy (BNCT) to treat patients in Japan with newly diagnosed or recurrent high-grade gliomas and have observed a significant increase in median survival time following BNCT. Although cerebrospinal fluid dissemination (CSFD) is not usually seen with the current standard therapy of patients with glioblastoma (GBM), here we report that subarachnoid or intraventricular CSFD was the most frequent cause of death for a cohort of our patients with high-grade gliomas who had been treated with BNCT. The study population consisted of 87 patients with supratentorial high-grade gliomas; 41 had newly diagnosed tumors and 46 had recurrent tumors. Thirty of 87 patients who were treated between January 2002 and July 2013 developed CSFD. Tumor histology before BNCT and immunohistochemical staining for two molecular markers, Ki-67 and IDH1 R132H , were evaluated for 20 of the 30 patients for whom pathology slides were available. Fluorescence in situ hybridization (FISH) was performed on 3 IDH1 R132H -positive and 1 control IDH1 R132H -negative tumors in order to determine chromosome 1p and 19q status. Histopathologic evaluation revealed that 10 of the 20 patients' tumors were IDH1 R132H -negative small cell GBMs. The remaining patients had tumors consisting of other IDH1 R132H -negative GBM variants, an IDH1 R132H -positive GBM and two anaplastic oligodendrogliomas. Ki-67 immunopositivity ranged from 2 to 75%. In summary, IDH1 R132H -negative GBMs, especially small cell GBMs, accounted for a disproportionately large number of patients who had CSF dissemination. This suggests that these tumor types had an increased propensity to disseminate via the CSF following BNCT and that these patients are at high risk for this clinically serious event.

Reduction of gate leakage current on AlGaN/GaN high electron mobility transistors by electron-beam irradiation.

PubMed

Oh, S K; Song, C G; Jang, T; Kim, Kwang-Choong; Jo, Y J; Kwak, J S

2013-03-01

This study examined the effect of electron-beam (E-beam) irradiation on the AIGaN/GaN HEMTs for the reduction of gate leakage. After E-beam irradiation, the gate leakage current significantly decreased from 2.68 x 10(-8) A to 4.69 x 10(-9) A at a drain voltage of 10 V. The maximum drain current density of the AIGaN/GaN HEMTs with E-beam irradiation increased 14%, and the threshold voltage exhibited a negative shift, when compared to that of the AIGaN/GaN HEMTs before E-beam irradiation. These results strongly suggest that the reduction of gate leakage current resulted from neutralization nitrogen vacancies and removing of oxygen impurities.

Microiontophoretic release of drugs from micropipettes

PubMed Central

Clarke, G.; Hill, R. G.; Simmonds, M. A.

1973-01-01

1. The use of 24Na+ of high specific activity allowed its iontophoretic release from multibarrelled glass micropipettes to be followed over short periods with low currents. 2. When a negative retaining current was passed to reduce diffusional efflux between the periods of positive current expulsion of 24Na+, the rate of release of 24Na+ during the expulsion period progressively increased during the first minute before becoming constant. 3. The currents employed were similar to those normally used to regulate the microiontophoretic release of potent drugs such as γ-aminobutyric acid. It is therefore concluded that, during the usual period of response to such drugs, the rate of release of drug is not constant but increasing. 4. The implications of these observations for the construction of microiontophoretic dose-response relationships is discussed. PMID:4724187

Characterization of the IMF By-dependent field-aligned currents in the cleft region based on DE 2 observations

NASA Technical Reports Server (NTRS)

Taguchi, S.; Sugiura, M.; Winningham, J. D.; Slavin, J. A.

1993-01-01

The magnetic field and plasma data from 47 passes of DE-2 are used to study the IMF By-dependent distribution of field-aligned currents in the cleft region. It is proposed that the low-latitude cleft current (LCC) region is not an extension of the region 1 or region 2 current system and that a pair of LCCs and high-latitude cleft currents (HCCs) constitutes the cleft field-aligned current regime. The proposed pair of cleft field-aligned currents is explained with a qualitative model in which this pair of currents is generated on open field lines that have just been reconnected on the dayside magnetopause. The electric fields are transmitted along the field lines to the ionosphere, creating a poleward electric field and a pair of field-aligned currents when By is positive; the pair of field-aligned currents consists of a downward current at lower latitudes and an upward current at higher latitudes. In the By negative case, the model explains the reversal of the field-aligned current direction in the LCC and HCC regions.

Cervical cancer screening intervals and management for women living with HIV: a risk benchmarking approach.

PubMed

Robbins, Hilary A; Strickler, Howard D; Massad, L Stewart; Pierce, Christopher B; Darragh, Teresa M; Minkoff, Howard; Keller, Marla J; Fischl, Margaret; Palefsky, Joel; Flowers, Lisa; Rahangdale, Lisa; Milam, Joel; Shrestha, Sadeep; Colie, Christine; DʼSouza, Gypsyamber

2017-04-24

We suggested cervical cancer screening strategies for women living with HIV (WLHIV) by comparing their precancer risks to general population women, and then compared our suggestions with current Centers for Disease Control and Prevention (CDC) guidelines. We compared risks of biopsy-confirmed cervical high-grade squamous intraepithelial neoplasia or worse (bHSIL+), calculated among WLHIV in the Women's Interagency HIV Study, to 'risk benchmarks' for specific management strategies in the general population. We applied parametric survival models among 2423 WLHIV with negative or atypical squamous cell of undetermined significance (ASC-US) cytology during 2000-2015. Separately, we synthesized published general population bHSIL+ risks to generate 3-year risk benchmarks for a 3-year return (after negative cytology, i.e. 'rescreening threshold'), a 6-12-month return (after ASC-US), and immediate colposcopy [after low-grade squamous intraepithelial lesion (LSIL)]. Average 3-year bHSIL+ risks among general population women ('risk benchmarks') were 0.69% for a 3-year return (after negative cytology), 8.8% for a 6-12-month return (after ASC-US), and 14.4% for colposcopy (after LSIL). Most CDC guidelines for WLHIV were supported by comparing risks in WLHIV to these benchmarks, including a 3-year return with CD4 greater than 500 cells/μl and after either three negative cytology tests or a negative cytology/oncogenic human papillomavirus cotest (all 3-year risks≤1.3%); a 1-year return after negative cytology with either positive oncogenic human papillomavirus cotest (1-year risk = 1.0%) or CD4 cell count less than 500 cells/μl (1-year risk = 1.1%); and a 6-12-month return after ASC-US (3-year risk = 8.2% if CD4 cell count at least 500 cells/μl; 10.4% if CD4 cell count = 350-499 cells/μl). Other suggestions differed modestly from current guidelines, including colposcopy (vs. 6-12 month return) for WLHIV with ASC-US and CD4 cell count less than 350 cells/μl (3-year risk = 16.4%) and a lengthened 2-year (vs. 1-year) interval after negative cytology with CD4 cell count at least 500 cells/μl (2-year risk = 0.98%). Current cervical cancer screening guidelines for WLHIV are largely appropriate. CD4 cell count may inform risk-tailored strategies.

Positive and Negative Affect More Concurrent among Blacks than Whites.

PubMed

Lankarani, Maryam Moghani; Assari, Shervin

2017-08-01

While positive and negative affect are inversely linked, people may experience and report both positive and negative emotions simultaneously. However, it is unknown if race alters the magnitude of the association between positive and negative affect. The current study compared Black and White Americans for the association between positive and negative affect. We used data from MIDUS (Midlife in the United States), a national study of Americans with an age range of 25 to 75. A total number of 7108 individuals were followed for 10 years from 1995 to 2004. Positive and negative affect was measured at baseline (1995) and follow-up (2004). Demographic (age and gender), socioeconomic (education and income) as well as health (self-rated health, chronic medical conditions, and body mass index) factors measured at baseline were covariates. A series of linear regressions were used to test the moderating effect of race on the reciprocal association between positive and negative affect at baseline and over time, net of covariates. In the pooled sample, positive and negative affect showed inverse correlation at baseline and over time, net of covariates. Blacks and Whites differed in the magnitude of the association between positive and negative affect, with weaker inverse associations among Blacks compared to Whites, beyond all covariates. Weaker reciprocal association between positive and negative affect in Blacks compared to Whites has implications for cross-racial measurement of affect and mood, including depression. Depression screening programs should be aware that race alters the concordance between positive and negative affect domains and that Blacks endorse higher levels of positive affect compared to Whites in the presence of high negative affect.

Negative Emotionality, Depressive Symptoms and Cortisol Diurnal Rhythms: Analysis of a Community Sample of Middle-Aged Males

PubMed Central

Doane, Leah D.; Franz, Carol E.; Prom-Wormley, Elizabeth; Eaves, Lindon J.; Mendoza, Sally P.; Hellhammer, Dirk H.; Lupien, Sonia; Xian, Hong; Lyons, Michael J.; Kremen, William; Jacobson, Kristen C.

2011-01-01

Prior research suggests that individuals with particular personality traits, like negative emotionality, are at greater risk for adverse health outcomes. Despite bivariate associations between negative emotionality, depressive symptoms and the hypothalamic pituitary adrenal axis (HPA axis), few studies have sought to understand the biological pathways through which negative emotionality, depressive symptomology and cortisol--one of the primary hormonal products of the HPA axis--are associated. The present study explored whether negative emotionality influenced cortisol dysregulation through current depressive symptomatology and whether negative emotionality served as a moderator of the relationship between depressive symptoms and cortisol. In the community-based Vietnam Era Twin Study of Aging, 783 male twins completed two days of cortisol saliva sampling in their natural environments. Three measures of cortisol were analyzed: waking levels, the cortisol awakening response, and the peak to bed slope. Depressive symptoms significantly mediated the associations between negative emotionality and the peak to bed slope. A 2-way interaction between depressive symptoms and negative emotionality was significant for the peak to bed slope and for waking levels of cortisol. Exploration of the interactions illustrated that depressive symptoms only affected cortisol slopes at average or high levels of negative emotionality and only affected waking levels at low levels of negative emotionality. Negative emotionality and depressive symptoms were not related to the cortisol awakening response. This is the first study to find indirect associations between negative emotionality and peak to bed cortisol slopes through depressive symptoms. These findings illustrate the complex interplay between personality characteristics, depressive symptoms and different indices of the cortisol diurnal rhythm. PMID:21619882

Reduced junction temperature and enhanced performance of high power light-emitting diodes using reduced graphene oxide pattern

NASA Astrophysics Data System (ADS)

Han, Nam; Jung, Eunjin; Han, Min; Deul Ryu, Beo; Bok Ko, Kang; Park, Young Jae; Cuong, TranViet; Cho, Jaehee; Kim, Hyunsoo; Hong, Chang-Hee

2015-07-01

Thermal management has become a crucial area for further development of high-power light-emitting didoes (LEDs) due to the high operating current densities that are required and result in additional joule heating. This increased joule heating negatively affects the performance of the LEDs since it greatly decreases both the optical performance and the lifetime. To circumvent this problem, a reduced graphene oxide (rGO) layer can be inserted to act as a heat spreader. In this study, current-voltage and light-output-current measurements are systematically performed at different temperatures from 30 to 190 °C to investigate the effect that the embedded rGO pattern has on the device performance. At a high temperature and high operating current, the junction temperature (Tj) is 23% lower and the external quantum efficiency (EQE) is 24% higher for the rGO embedded LEDs relative to those of conventional LEDs. In addition, the thermal activation energy of the rGO embedded LEDs exhibits a 30% enhancement as a function of the temperature at a bias of  -5 V. This indicates that the rGO pattern plays an essential role in decreasing the junction temperature and results in a favorable performance in terms of the temperature of the high power GaN-based LED junction.

Study of electron transport across the magnetic filter of NIO1 negative ion source

NASA Astrophysics Data System (ADS)

Veltri, P.; Sartori, E.; Cavenago, M.; Serianni, G.; Barbisan, M.; Zaniol, B.

2017-08-01

In the framework of the accompanying activities in support to the ITER NBI test facility, a relatively compact radiofrequency (RF) ion source, named NIO1 (Negative Ion Optimization, phase 1) was developed in Padua, Italy, in collaboration between Consorzio RFX and INFN. Negative hydrogen ions are formed in a cold, inductively coupled plasma with a 2MHz, 2.5 kW external antenna. A low electron energy is necessary to increase the survival probability of negative ions in the proximity of the extraction area. This goal is accomplished by means of a transversal magnetic field, confining the high energy electrons better than the colder electrons. In NIO1, this filter field can cover different topologies, exploiting different set of magnets and high current paths. In this contribution we study the property of the plasma in the vicinity of the extraction region for two different B field configurations. For this experiment the source was operated in pure volume conditions, in hydrogen and oxygen plasmas. The experimental data, measured by spectroscopic means, is interpreted also with the support of finite element analyses simulations of the magnetic field and a dedicated particle in cell (PIC) numerical model for the electron transport across it, including Coulomb and gas collisions.

Repetitive transcranial magnetic stimulation modulates the impact of a negative mood induction.

PubMed

Möbius, Martin; Lacomblé, Lylis; Meyer, Thomas; Schutter, Dennis J L G; Gielkens, Tom; Becker, Eni S; Tendolkar, Indira; van Eijndhoven, Philip

2017-04-01

High frequency repetitive Transcranial Magnetic Stimulation (rTMS) over the left dorsolateral prefrontal cortex (DLPFC) has been found to alleviate depressive symptoms. However, the mechanisms driving these effects are still poorly understood. In the current study, we tested the idea that this intervention protects against negative mood shifts following emotional provocation. We furthermore explored changes in EEG activity (frontal alpha asymmetry) and effects on attentional processing (emotional Stroop). To this end, 23 healthy individuals participated in two sessions separated by one week, whereby they once received 15 min of 10Hz rTMS stimulation (1500 pulses) at 110% of the individual motor threshold, and once sham stimulation. Then, negative mood was induced using sad movie clips. The results revealed a significantly stronger mood decline following rTMS compared to sham stimulation. No changes were observed in frontal alpha asymmetry and attentional processing. Our findings are at odds with the view that high frequency rTMS over the left DLPFC directly protects against the induction of negative mood, but rather suggest that it enhances the effects of emotional provocation. Possibly, in healthy young individuals, this stimulation protocol heightens susceptibility to mood induction procedures in general. © The Author (2016). Published by Oxford University Press.

Alcohol-Related Negative Consequences among Drinkers around the World

PubMed Central

Graham, Kathryn; Bernards, Sharon; Knibbe, Ronald; Kairouz, Sylvia; Kuntche, Sandra; Wilsnack, Sharon C.; Greenfield, Thomas K.; Dietze, Paul; Obot, Isidore; Gmel, Gerhard

2013-01-01

Aims This paper examines (1) gender and country differences in negative consequences related to drinking; (2) relative rates of different consequences; (3) country-level predictors of consequences. Design, setting and participants Multi-level analyses used survey data from the GENACIS collaboration. Measurements Measures included 17 negative consequences grouped into (a) high endorsement acute, (b) personal and (c) social. Country-level measures included average frequency and quantity of drinking, percent current drinkers, Gross Domestic Product (GDP) and Human Development Index (HDI). Findings Overall, the three groupings of consequences were reported by 44%, 12% and 7% of men and by 31%, 6% and 3% of women, respectively. More men than women endorsed all consequences but gender differences were greatest for consequences associated with chronic drinking and social consequences related to male roles. The highest prevalence of consequences was in Uganda, lowest in Uruguay. Personal and social consequences were more likely in countries with higher usual quantity, fewer current drinkers, and lower scores on GDP and HDI. However, significant interactions with individual-level quantity indicated a stronger relationship between consequences and usual quantity among drinkers in countries with lower quantity, more current drinkers and higher scores on GDP and HDI. Conclusions Both gender and country need to be taken into consideration when assessing adverse drinking consequences. Individual measures of alcohol consumption and country-level variables are associated with experiencing such consequences. Additionally, country-level variables affect the strength of the relationship between usual quantity consumed by individuals and adverse consequences. PMID:21395893

Fitting in and standing out: increasing the use of alcohol protective behavioral strategies with a deviance regulation intervention.

PubMed

Dvorak, Robert D; Pearson, Matthew R; Neighbors, Clayton; Martens, Matthew P

2015-06-01

Heavy alcohol use remains a consistent public health concern on college campuses. The current pilot study used deviance regulation theory (DRT) to modify protective behavioral strategies (PBS) among college student drinkers to reduce alcohol use and alcohol-related consequences. The sample was comprised of current college student drinkers (n = 76; 53.95% female) ranging in age from 18-24 (M = 19.29, SD = 1.42). Participants were randomly assigned to receive a positively or negatively framed message. They then reported on use of alcohol PBS (via the Protective Behavioral Strategies Scale), alcohol consumption (via the Modified Daily Drinking Questionnaire), and alcohol-related consequences (via the Young Adult Alcohol Consequences Questionnaire) each week for 6 weeks. Among drinkers with low PBS use norms, a positively, versus a negatively, framed message resulted in increased PBS use and consequently less alcohol consumption and fewer alcohol-related consequences. Among drinkers with high PBS use norms, a negatively, versus positively, framed message resulted in increased PBS use and consequently lower alcohol consumption and fewer alcohol-related consequences. However, these effects were only relevant among those who strongly believed the DRT frame. Findings suggest assigning drinkers to frames based on perceived PBS use norms and increasing belief in the frame may be 1 approach to increasing responsible drinking patterns among college students. Furthermore, the current data suggests important boundary conditions for norm-based interventions. (c) 2015 APA, all rights reserved).

High Willingness to Use HIV Pre-Exposure Prophylaxis Among Transgender Women in Argentina.

PubMed

Zalazar, Virginia; Arístegui, Inés; Kerr, Thomas; Marshall, Brandon D L; Romero, Marcela; Sued, Omar; Socías, M Eugenia

2016-01-01

Purpose: In Argentina, transgender women face a disproportionately high prevalence of HIV infection (34%). Although not currently approved in Argentina, pre-exposure prophylaxis (PrEP) may offer a potential effective HIV prevention tool for this population. In this study, we assessed the willingness to use PrEP among transgender women in Argentina. Methods: Data were drawn from a nationwide cross-sectional survey conducted among transgender women in 2013. Using multivariable logistic regression, we assessed the prevalence of and factors associated with willingness to use PrEP among transgender women with negative or unknown HIV status. Results: This study included 337 transgender women (278 HIV negative and 59 with unknown HIV status), most of whom had a history of sex work involvement (81.8%). Overall, 301 (89.3%) expressed willingness to use PrEP. In a multivariable analysis, having casual sexual partners was positively associated with willingness to use PrEP (adjusted odds ratio [AOR]=4.26, 95% confidence interval [CI] 1.73-10.51), while discrimination by healthcare workers was negatively associated (AOR=0.33, 95% CI 0.12-0.88). Conclusion: We found high levels of willingness to use PrEP among transgender women in Argentina, suggesting that there is high perception of HIV risk in this population. However, discrimination by healthcare workers was a strong negative correlate of willingness to use PrEP, suggesting that multilevel interventions that address gender-based stigma in healthcare settings will be critical for the success of PrEP as an HIV prevention strategy in this population.

High Willingness to Use HIV Pre-Exposure Prophylaxis Among Transgender Women in Argentina

PubMed Central

Zalazar, Virginia; Arístegui, Inés; Kerr, Thomas; Marshall, Brandon D.L.; Romero, Marcela; Sued, Omar; Socías, M. Eugenia

2016-01-01

Abstract Purpose: In Argentina, transgender women face a disproportionately high prevalence of HIV infection (34%). Although not currently approved in Argentina, pre-exposure prophylaxis (PrEP) may offer a potential effective HIV prevention tool for this population. In this study, we assessed the willingness to use PrEP among transgender women in Argentina. Methods: Data were drawn from a nationwide cross-sectional survey conducted among transgender women in 2013. Using multivariable logistic regression, we assessed the prevalence of and factors associated with willingness to use PrEP among transgender women with negative or unknown HIV status. Results: This study included 337 transgender women (278 HIV negative and 59 with unknown HIV status), most of whom had a history of sex work involvement (81.8%). Overall, 301 (89.3%) expressed willingness to use PrEP. In a multivariable analysis, having casual sexual partners was positively associated with willingness to use PrEP (adjusted odds ratio [AOR]=4.26, 95% confidence interval [CI] 1.73–10.51), while discrimination by healthcare workers was negatively associated (AOR=0.33, 95% CI 0.12–0.88). Conclusion: We found high levels of willingness to use PrEP among transgender women in Argentina, suggesting that there is high perception of HIV risk in this population. However, discrimination by healthcare workers was a strong negative correlate of willingness to use PrEP, suggesting that multilevel interventions that address gender-based stigma in healthcare settings will be critical for the success of PrEP as an HIV prevention strategy in this population. PMID:28861540

Fear of negative evaluation modulates electrocortical and behavioral responses when anticipating social evaluative feedback

PubMed Central

Van der Molen, Melle J. W.; Poppelaars, Eefje S.; Van Hartingsveldt, Caroline T. A.; Harrewijn, Anita; Gunther Moor, Bregtje; Westenberg, P. Michiel

2014-01-01

Cognitive models posit that the fear of negative evaluation (FNE) is a hallmark feature of social anxiety. As such, individuals with high FNE may show biased information processing when faced with social evaluation. The aim of the current study was to examine the neural underpinnings of anticipating and processing social-evaluative feedback, and its correlates with FNE. We used a social judgment paradigm in which female participants (N = 31) were asked to indicate whether they believed to be socially accepted or rejected by their peers. Anticipatory attention was indexed by the stimulus preceding negativity (SPN), while the feedback-related negativity and P3 were used to index the processing of social-evaluative feedback. Results provided evidence of an optimism bias in social peer evaluation, as participants more often predicted to be socially accepted than rejected. Participants with high levels of FNE needed more time to provide their judgments about the social-evaluative outcome. While anticipating social-evaluative feedback, SPN amplitudes were larger for anticipated social acceptance than for social rejection feedback. Interestingly, the SPN during anticipated social acceptance was larger in participants with high levels of FNE. None of the feedback-related brain potentials correlated with the FNE. Together, the results provided evidence of biased information processing in individuals with high levels of FNE when anticipating (rather than processing) social-evaluative feedback. The delayed response times in high FNE individuals were interpreted to reflect augmented vigilance imposed by the upcoming social-evaluative threat. Possibly, the SPN constitutes a neural marker of this vigilance in females with higher FNE levels, particularly when anticipating social acceptance feedback. PMID:24478667

The Association Between Suicidal Behavior, Attentional Control, and Frontal Asymmetry

PubMed Central

Thompson, Catherine; Ong, Elsie Li Chen

2018-01-01

It can be difficult to identify those at risk of suicide because suicidal thoughts are often internalized and not shared with others. Yet to prevent suicide attempts it is crucial to identify suicidal thoughts and actions at an early stage. Past studies have suggested that deficits in attentional control are associated with suicide, with the argument that individuals are unable to inhibit negative thoughts and direct resources away from negative information. The current study aimed to investigate the association of suicidal behavior with neurological and behavioral markers, measuring attentional bias and inhibition in two Stroop tasks. Fifty-four participants responded to the color of color words in a standard Stroop task and the color of positive, negative, and neutral words in an emotional Stroop task. Electroencephalographic (EEG) activity was recorded from frontal areas during each task and at resting. Participants were separated into a low-risk and high-risk group according to their self-reported suicidal behavior. Participants in the high-risk group showed slower response times in the color Stroop and reduced accuracy to incongruent trials, but faster response times in the emotional Stroop task. Response times to the word “suicide” were significantly slower for the high-risk group. This indicates an attentional bias toward specific negative stimuli and difficulties inhibiting information for those with high levels of suicidal behavior. In the emotional Stroop task the high-risk group showed reduced activity in leftward frontal areas, suggesting limitations in the ability to regulate emotional processing via the left frontal regions. The findings support the argument that deficits in attentional control are related to suicidal behavior. The research also suggests that under certain conditions frontal asymmetry may be associated with suicidal behavior. PMID:29593586

Negative pressure wound therapy for high-risk wounds in lower extremity revascularization: study protocol for a randomized controlled trial.

PubMed

Murphy, Patrick; Lee, Kevin; Dubois, Luc; DeRose, Guy; Forbes, Thomas; Power, Adam

2015-11-04

Rates of surgical site infections (SSIs) following groin incision for femoral artery exposure are much higher than expected of a clean operation. The morbidity and mortality is high, particularly with the use of prosthetic grafts. The vascular surgery population is at an increased risk of SSIs related to peripheral vascular disease (PVD), diabetes, obesity, previous surgery and presence of tissue loss. Negative pressure wound therapy (NPWT) dressings have been used on primarily closed incisions to reduce surgical site infections in other surgical disciplines. We have not come across any randomized controlled trials to support the prophylactic use of negative pressure wound therapy in high-risk vascular patients undergoing lower limb revascularization. In this single-center, prospective randomized controlled trial, patients scheduled for a lower limb revascularization requiring open femoral artery exposure who are at a high risk (BMI > 30 kg/m(2), previous femoral cutdown or Rutherford V or VI category for chronic limb ischemia) will be eligible for the study. A total of 108 groin incisions will be randomized to the use of a negative pressure wound device or standard adhesive gauze dressing. Patients will be followed in hospital and reassessed within the first 30 days postoperatively. The primary outcome is SSI within the first 30 days of surgery and will be determined using the intention-to-treat principle. Secondary outcomes include length of stay, emergency room visits, reoperation, amputation and mortality. A cost analysis will be performed. The trial is expected to define the role of NPWT in SSI prophylaxis for lower limb revascularization in high-risk vascular patients. The results of the study will be used to inform current best practice for perioperative care and the minimization of SSIs. NCT02084017 , March 2014.

A Commercial Conducting Polymer as Both Binder and Conductive Additive for Silicon Nanoparticle-Based Lithium-Ion Battery Negative Electrodes.

PubMed

Higgins, Thomas M; Park, Sang-Hoon; King, Paul J; Zhang, Chuanfang John; McEvoy, Niall; Berner, Nina C; Daly, Dermot; Shmeliov, Aleksey; Khan, Umar; Duesberg, Georg; Nicolosi, Valeria; Coleman, Jonathan N

2016-03-22

This work describes silicon nanoparticle-based lithium-ion battery negative electrodes where multiple nonactive electrode additives (usually carbon black and an inert polymer binder) are replaced with a single conductive binder, in this case, the conducting polymer PSS. While enabling the production of well-mixed slurry-cast electrodes with high silicon content (up to 95 wt %), this combination eliminates the well-known occurrence of capacity losses due to physical separation of the silicon and traditional inorganic conductive additives during repeated lithiation/delithiation processes. Using an in situ secondary doping treatment of the PSS with small quantities of formic acid, electrodes containing 80 wt % SiNPs can be prepared with electrical conductivity as high as 4.2 S/cm. Even at the relatively high areal loading of 1 mg/cm(2), this system demonstrated a first cycle lithiation capacity of 3685 mA·h/g (based on the SiNP mass) and a first cycle efficiency of ∼78%. After 100 repeated cycles at 1 A/g this electrode was still able to store an impressive 1950 mA·h/g normalized to Si mass (∼75% capacity retention), corresponding to 1542 mA·h/g when the capacity is normalized by the total electrode mass. At the maximum electrode thickness studied (∼1.5 mg/cm(2)), a high areal capacity of 3 mA·h/cm(2) was achieved. Importantly, these electrodes are based on commercially available components and are produced by the standard slurry coating methods required for large-scale electrode production. Hence, the results presented here are highly relevant for the realization of commercial LiB negative electrodes that surpass the performance of current graphite-based negative electrode systems.

Evaluation of zona pellucida birefringence intensity during in vitro maturation of oocytes from stimulated cycles.

PubMed

Petersen, Claudia G; Vagnini, Laura D; Mauri, Ana L; Massaro, Fabiana C; Silva, Liliane F I; Cavagna, Mario; Baruffi, Ricardo L R; Oliveira, Joao B A; Franco, José G

2011-04-23

This study evaluated whether there is a relationship between the zona pellucida birefringence (ZP-BF) intensity and the nuclear (NM) and cytoplasmic (CM) in vitro maturation of human oocytes from stimulated cycles. The ZP-BF was evaluated under an inverted microscope with a polarizing optical system and was scored as high/positive (when the ZP image presented a uniform and intense birefringence) or low/negative (when the image presented moderate and heterogeneous birefringence). CM was analyzed by evaluating the distribution of cortical granules (CGs) throughout the ooplasm by immunofluorescence staining. CM was classified as: complete, when CG was localized in the periphery; incomplete, when oocytes presented a cluster of CGs in the center; or in transition, when oocytes had both in clusters throughout cytoplasm and distributed in a layer in the cytoplasm periphery Nuclear maturation: From a total of 83 germinal vesicle (GV) stage oocytes, 58 of oocytes (69.9%) reached NM at the metaphase II stage. From these 58 oocytes matured in vitro, the high/positively scoring ZP-BF was presented in 82.7% of oocytes at the GV stage, in 75.8% of oocytes when at the metaphase I, and in 82.7% when oocytes reached MII. No relationship was observed between NM and ZP-BF positive/negative scores (P = 0.55). These variables had a low Pearson's correlation coefficient (r = 0.081). Cytoplasmic maturation: A total of 85 in vitro-matured MII oocytes were fixed for CM evaluation. Forty-nine oocytes of them (57.6%) showed the complete CM, 30 (61.2%) presented a high/positively scoring ZP-BF and 19 (38.8%) had a low/negatively scoring ZP-BF. From 36 oocytes (42.3%) with incomplete CM, 18 (50%) presented a high/positively scoring ZPBF and 18 (50%) had a low/negatively scoring ZP-BF. No relationship was observed between CM and ZP-BF positive/negative scores (P = 0.42). These variables had a low Pearson's correlation coefficient (r = 0.11). The current study demonstrated an absence of relationship between ZP-BF high/positive or low/negative score and nuclear and cytoplasmic in vitro maturation of oocytes from stimulation cycles.

To Legalize or not to Legalize? That is the Question

DTIC Science & Technology

2009-04-01

and international community to improve security and promote development in Afghanistan. The negative effect on the nations overall security, the...the problem/solution methodology. The research explores the current illicit opium cultivation in Afghanistan and its effect on the current...negative effect on the current development efforts. 15. SUBJECT TERMS 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT SAR 18. NUMBER OF

A first insight into high prevalence of undiagnosed smear-negative pulmonary tuberculosis in Northern Ethiopian prisons: implications for greater investment and quality control.

PubMed

Biadglegne, Fantahun; Rodloff, Arne C; Sack, Ulrich

2014-01-01

Tuberculosis (TB) transmission in prisons poses significant risks to inmates as well as the general population. Currently, there are no data on smear-negative pulmonary TB cases in prisons and by extension no data on the impact such cases have on TB incidence. This study was designed to obtain initial data on the prevalence of smear-negative cases of TB in prisons as well as preliminary risk factor analysis for such TB cases. This cross-sectional survey was conducted in November 2013 at eight main prisons located in the state of Amhara, Ethiopia. Interviews using a structured and pretested questionnaire were done first to identify symptomatic prisoners. Three consecutive sputum samples were collected and examined using acid fast bacilli (AFB) microscopy at the point of care. All smear-negative sputum samples were taken for culture and Xpert testing. Descriptive and multivariate analysis was done using SPSS version 16. Overall the prevalence of smear-negative pulmonary TB cases in the study prisons was 8% (16/200). Using multivariate analysis, a contact history to TB patients in prison, educational level, cough and night sweating were found to be predictors of TB positivity among smear-negative pulmonary TB cases (p ≤ 0.05). In the studied prisons, high prevalence of undiagnosed TB cases using AFB microscopy was documented, which is an important public health concern that urgently needs to be addressed. Furthermore, patients with night sweating, non-productive cough, a contact history with TB patients and who are illiterate merit special attention, larger studies are warranted in the future to assess the associations more precisely. Further studies are also needed to examine TB transmission dynamics by patients with smear-negative pulmonary TB in a prison setting.

Prevention of ER-Negative Breast Cancer

PubMed Central

Li, Yuxin

2014-01-01

The successful demonstration that the selective estrogen receptor modulators (SERMs) tamoxifen and raloxifene reduce the risk of breast cancer has stimulated great interest in using drugs to prevent breast cancer in high-risk women. In addition, recent results from breast cancer treatment trials suggest that aromatase inhibitors may be even more effective at preventing breast cancer than are SERMs. However, while SERMs and aromatase inhibitors do prevent the development of many estrogen-receptor (ER)-positive breast cancers, these drugs do not prevent the development of ER-negative breast cancer. Thus, there is an urgent need to identify agents that can prevent ER-negative breast cancer. We have studied the cancer preventative activity of several classes of drugs for their ability to prevent ER-negative breast cancer in preclinical models. Results from these studies demonstrate that rexinoids (analogs of retinoids that bind and activate RXR receptors), tyrosine kinase inhibitors (such as EGFR inhibitors and dual kinase inhibitors that block EGFR and HER2/neu signaling), and cyclo-oxygenase 2 (COX-2) inhibitors all prevent ER-negative breast cancer in transgenic mice that develop ER-negative breast cancer. Other promising agents now under investigation include vitamin D and vitamin D analogs, drugs that activate PPAR-gamma nuclear receptors, and statins. Many of these agents are now being tested in early phase cancer prevention clinical trials to determine whether they will show activity in breast tissue and whether they are safe for use in high-risk women without breast cancer. The current status of these studies will be reviewed. It is anticipated that in the future, drugs that effectively prevent ER-negative breast cancer will be used in combination with hormonal agents such SERMs or aromatase inhibitors to prevent all forms of breast cancer. PMID:19213564

Quantifying the effects of ozone on plant reproductive growth and development

USDA-ARS?s Scientific Manuscript database

Tropospheric ozone is a harmful air pollutant that can negatively impact plant growth and development. Current ozone concentrations negatively impact forest productivity and crop yields, and future ozone concentrations will increase if current emission rates continue. However, the specific effects o...

Potential strategies for the eradication of multidrug-resistant Gram-negative bacterial infections.

PubMed

Huwaitat, Rawan; McCloskey, Alice P; Gilmore, Brendan F; Laverty, Garry

2016-07-01

Antimicrobial resistance is one of the leading threats to society. The increasing burden of multidrug-resistant Gram-negative infection is particularly concerning as such bacteria are demonstrating resistance to nearly all currently licensed therapies. Various strategies have been hypothesized to treat multidrug-resistant Gram-negative infections including: targeting the Gram-negative outer membrane; neutralization of lipopolysaccharide; inhibition of bacterial efflux pumps and prevention of protein folding. Silver and silver nanoparticles, fusogenic liposomes and nanotubes are potential strategies for extending the activity of licensed, Gram-positive selective, antibiotics to Gram-negatives. This may serve as a strategy to fill the current void in pharmaceutical development in the short term. This review outlines the most promising strategies that could be implemented to solve the threat of multidrug-resistant Gram-negative infections.

A computerized Langmuir probe system

NASA Astrophysics Data System (ADS)

Pilling, L. S.; Bydder, E. L.; Carnegie, D. A.

2003-07-01

For low pressure plasmas it is important to record entire single or double Langmuir probe characteristics accurately. For plasmas with a depleted high energy tail, the accuracy of the recorded ion current plays a critical role in determining the electron temperature. Even for high density Maxwellian distributions, it is necessary to accurately model the ion current to obtain the correct electron density. Since the electron and ion current saturation values are, at best, orders of magnitude apart, a single current sensing resistor cannot provide the required resolution to accurately record these values. We present an automated, personal computer based data acquisition system for the determination of fundamental plasma properties in low pressure plasmas. The system is designed for single and double Langmuir probes, whose characteristics can be recorded over a bias voltage range of ±70 V with 12 bit resolution. The current flowing through the probes can be recorded within the range of 5 nA-100 mA. The use of a transimpedance amplifier for current sensing eliminates the requirement for traditional current sensing resistors and hence the need to correct the raw data. The large current recording range is realized through the use of a real time gain switching system in the negative feedback loop of the transimpedance amplifier.

Primary Gastric ALK-negative EBV-negative Anaplastic Large Cell Lymphoma Presenting with Iron Deficiency Anemia.

PubMed

Zhang, Wei; Burton, Samuel; Wu, Shaobin; Qian, Xia; Rajeh, Mhd Nabeel; Schroeder, Katie; Shuldberg, Mark; Merando, Adam; Lai, Jin-Ping

2017-01-01

Anaplastic large cell lymphoma (ALCL) is a rare subtype of non-Hodgkin lymphoma (NHL). Primary gastric anaplastic lymphoma kinase (ALK) negative ALCL is extremely rare. Diagnosis of primary gastric ALK-negative ALCL is difficult to establish and prognosis is worse than ALK-positive ALCL. Here, we report a case of an 82-year-old man with a history of cerebrovascular disease presented with weakness and iron deficiency anemia. He denied any abdominal discomforts. The esophagogastroduodenoscopy revealed a large ulcerated, friable mass in the gastric body which encompassed about 80% of entire stomach. Biopsy showed a high grade malignant tumor composed of undifferentiated epithelioid atypical cells, making it difficult to determine the cell of origin. Immunostains for lymphoma, carcinoma, and sarcoma were performed. The tumor cells were positive for CD30, CD4, and CD43, negative for CD20, CD3, ALK-1 and Epstein-Barr virus (EBV)-encoded small RNAs (EBERs) in situ hybridization, establishing the diagnosis of primary gastric ALK-negative ALCL. The patient is currently undergoing chemotherapy with clinical improvement. To the best of our knowledge, this is the first reported case of primary gastric ALK-negative and EBV-negative anaplastic large T-cell lymphoma that presented without gastroenterological symptoms. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

Bulk-Type All-Solid-State Lithium-Ion Batteries: Remarkable Performances of a Carbon Nanofiber-Supported MgH2 Composite Electrode.

PubMed

Zeng, Liang; Ichikawa, Takayuki; Kawahito, Koji; Miyaoka, Hiroki; Kojima, Yoshitsugu

2017-01-25

Magnesium hydride, MgH 2 , a recently developed compound for lithium-ion batteries, is considered to be a promising conversion-type negative electrode material due to its high theoretical lithium storage capacity of over 2000 mA h g -1 , suitable working potential, and relatively small volume expansion. Nevertheless, it suffers from unsatisfactory cyclability, poor reversibility, and slow kinetics in conventional nonaqueous electrolyte systems, which greatly limit the practical application of MgH 2 . In this work, a vapor-grown carbon nanofiber was used to enhance the electrical conductivity of MgH 2 using LiBH 4 as the solid-state electrolyte. It shows that a reversible capacity of over 1200 mA h g -1 with an average voltage of 0.5 V (vs Li/Li + ) can be obtained after 50 cycles at a current density of 1000 mA g -1 . In addition, the capacity of MgH 2 retains over 1100 mA h g -1 at a high current density of 8000 mA g -1 , which indicates the possibility of using MgH 2 as a negative electrode material for high power and high capacity lithium-ion batteries in future practical applications. Moreover, the widely studied sulfide-based solid electrolyte was also used to assemble battery cells with MgH 2 electrode in the same system, and the electrochemical performance was as good as that using LiBH 4 electrolyte.

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

Jordanova, Vania K

Understanding the response at Earth of the Sun's varying energy output and forecasting geomagnetic activity is of central interest to space science, since intense geomagnetic storms may cause severe damages on technological systems and affect communications. Episodes of southward (Bz

Leakage current conduction mechanisms and electrical properties of atomic-layer-deposited HfO2/Ga2O3 MOS capacitors

NASA Astrophysics Data System (ADS)

Zhang, Hongpeng; Jia, Renxu; Lei, Yuan; Tang, Xiaoyan; Zhang, Yimen; Zhang, Yuming

2018-02-01

In this paper, current conduction mechanisms in HfO2/β-Ga2O3 metal-oxide-semiconductor (MOS) capacitors under positive and negative biases are investigated using the current-voltage (I-V) measurements conducted at temperatures from 298 K to 378 K. The Schottky emission is dominant under positively biased electric fields of 0.37-2.19 MV cm-1, and the extracted Schottky barrier height ranged from 0.88 eV to 0.91 eV at various temperatures. The Poole-Frenkel emission dominates under negatively biased fields of 1.92-4.83 MV cm-1, and the trap energy levels are from 0.71 eV to 0.77 eV at various temperatures. The conduction band offset (ΔE c) of HfO2/β-Ga2O3 is extracted to be 1.31  ±  0.05 eV via x-ray photoelectron spectroscopy, while a large negative sheet charge density of 1.04  ×  1013 cm-2 is induced at the oxide layer and/or HfO2/β-Ga2O3 interface. A low C-V hysteresis of 0.76 V, low interface state density (D it) close to 1  ×  1012 eV-1 cm-2, and low leakage current density of 2.38  ×  10-5 A cm-2 at a gate voltage of 7 V has been obtained, suggesting the great electrical properties of HfO2/β-Ga2O3 MOSCAP. According to the above analysis, ALD-HfO2 is an attractive candidate for high voltage β-Ga2O3 power devices.

Menstruation across time: menarche, menstrual attitudes, experiences, and behaviors.

PubMed

McPherson, Marianne E; Korfine, Lauren

2004-01-01

This study explored the relationship between early and current menstrual experiences. The primary hypothesis was that women who reported positive menarcheal experiences (including menstrual education and menarche) would tend to report positive current menstrual attitudes, experiences, and/or behaviors, and vice versa for women who reported negative menarcheal experiences. In this survey-based study, college-aged women (n = 327) were screened by completing a questionnaire concerning their menarcheal experiences. Women who had extremely negative ("negative group," n = 46) or extremely positive ("positive group," n = 38) early menstrual experiences returned to complete questionnaires concerning current menstrual attitudes, experiences, and behaviors. Early and current menstrual experiences were most strongly associated in the domain of menstrual attitudes. Women in the negative group reported more negative menstrual attitudes than did women in the positive group. There were additional associations between early menstrual experiences and measures of body image and health behaviors. Positive group participants reported more positive body image and better general health behaviors. Results suggest that early menstrual experiences may be related to menstrual experiences later in life. This study invites further investigation of the psychology of menstruation and suggests connecting menstruation with other women's health issues.

Daydreaming style moderates the relation between working memory and mind wandering: Integrating two hypotheses.

PubMed

Marcusson-Clavertz, David; Cardeña, Etzel; Terhune, Devin Blair

2016-03-01

Mind wandering-mentation unrelated to one's current activity and surroundings-is a ubiquitous phenomenon, but seemingly competing ideas have been proposed regarding its relation to executive cognitive processes. The control-failure hypothesis postulates that executive processes prevent mind wandering, whereas the global availability hypothesis proposes that mind wandering requires executive resources, and thus an excess of such resources enables mind wandering. Here, we examined whether these hypotheses could be reconciled by considering the moderating influence of daydreaming style. We expected that executive resources would be positively related to mind wandering in those who typically experience positive mind wandering mentation, but negatively related in those who typically experience negative mentation. One hundred eleven participants reported mind wandering over 4 days using experience sampling and completed the sustained attention to response task (SART), the symmetry span task, and the Stroop task. There was a significant interaction between working memory and negative, but not positive, daydreaming style on mind wandering: Working memory related positively to mind wandering in those with a low negative style, but negatively in those with a high negative style. In contrast, poor Stroop performance significantly predicted increased mind wandering, but only in those with a low positive style. SART responses did not predict mind wandering although the relation was suggestively enhanced as the difficulty of daily life activities increased, indicating that the SART is more generalizable to high-demanding than low-demanding activities. These results suggest that the content and context of mind wandering episodes play important roles in the relation between executive processes and mind wandering. (c) 2016 APA, all rights reserved).

The Prospective Joint Effects of Self-Regulation and Impulsive Processes on Early Adolescence Alcohol Use

PubMed Central

O’Connor, Roisin M.; Colder, Craig R.

2015-01-01

Objective: Dual-process models propose that behavior is influenced by the interactive effect of impulsive (automatic) and selfregulatory (controlled) processes. Elaborations of this model posit that the effect of impulsive processes on alcohol use is influenced by capacity and motivation to self-regulate. The interactive effect of these three processes on drinking has not previously been tested. The goal of this study was to provide a developmental extension of this model to early adolescent alcohol use and to test the three-way interaction between impulsive processes (implicit alcohol cognition), self-regulatory capacity (inhibitory and activation control), and self-regulatory motivation (negative alcohol outcome expectancies [AOE]) in a 1-year prospective prediction of adolescent alcohol use. Method: Adolescents (N = 325; 54% girls, mean age = 13.6 years at baseline) completed the Single Category Implicit Association Test and self-reports of alcohol expectancies and use. Inhibitory and activation control were based on parental report. Results: Negative AOE and inhibitory/activation control were supported as moderators of the effect of implicit alcohol cognition on 1-year prospective alcohol use. As expected, weak implicit negative alcohol cognition was associated with elevated alcohol use when both negative AOE and inhibitory control were low. Contrary to hypothesis, when activation control was high, weak implicit negative alcohol cognition was unrelated to alcohol use if negative AOE were high (p = .72) (vs. low, p < .01).Activation control may reflect the ability to plan ahead and act pro-socially. Conclusions: Our study supports current theory suggesting alcohol use is influenced by a complex interplay of impulsive and self-regulatory processes. PMID:26562596

Highly accurate prediction of emotions surrounding the attacks of September 11, 2001 over 1-, 2-, and 7-year prediction intervals.

PubMed

Doré, Bruce P; Meksin, Robert; Mather, Mara; Hirst, William; Ochsner, Kevin N

2016-06-01

In the aftermath of a national tragedy, important decisions are predicated on judgments of the emotional significance of the tragedy in the present and future. Research in affective forecasting has largely focused on ways in which people fail to make accurate predictions about the nature and duration of feelings experienced in the aftermath of an event. Here we ask a related but understudied question: can people forecast how they will feel in the future about a tragic event that has already occurred? We found that people were strikingly accurate when predicting how they would feel about the September 11 attacks over 1-, 2-, and 7-year prediction intervals. Although people slightly under- or overestimated their future feelings at times, they nonetheless showed high accuracy in forecasting (a) the overall intensity of their future negative emotion, and (b) the relative degree of different types of negative emotion (i.e., sadness, fear, or anger). Using a path model, we found that the relationship between forecasted and actual future emotion was partially mediated by current emotion and remembered emotion. These results extend theories of affective forecasting by showing that emotional responses to an event of ongoing national significance can be predicted with high accuracy, and by identifying current and remembered feelings as independent sources of this accuracy. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Highly accurate prediction of emotions surrounding the attacks of September 11, 2001 over 1-, 2-, and 7-year prediction intervals

PubMed Central

Doré, B.P.; Meksin, R.; Mather, M.; Hirst, W.; Ochsner, K.N

2016-01-01

In the aftermath of a national tragedy, important decisions are predicated on judgments of the emotional significance of the tragedy in the present and future. Research in affective forecasting has largely focused on ways in which people fail to make accurate predictions about the nature and duration of feelings experienced in the aftermath of an event. Here we ask a related but understudied question: can people forecast how they will feel in the future about a tragic event that has already occurred? We found that people were strikingly accurate when predicting how they would feel about the September 11 attacks over 1-, 2-, and 7-year prediction intervals. Although people slightly under- or overestimated their future feelings at times, they nonetheless showed high accuracy in forecasting 1) the overall intensity of their future negative emotion, and 2) the relative degree of different types of negative emotion (i.e., sadness, fear, or anger). Using a path model, we found that the relationship between forecasted and actual future emotion was partially mediated by current emotion and remembered emotion. These results extend theories of affective forecasting by showing that emotional responses to an event of ongoing national significance can be predicted with high accuracy, and by identifying current and remembered feelings as independent sources of this accuracy. PMID:27100309

A method to stabilise the performance of negatively fed KM3NeT photomultipliers

NASA Astrophysics Data System (ADS)

Adrián-Martínez, S.; Ageron, M.; Aiello, S.; Albert, A.; Ameli, F.; Anassontzis, E. G.; Andre, M.; Androulakis, G.; Anghinolfi, M.; Anton, G.; Ardid, M.; Avgitas, T.; Barbarino, G.; Barbarito, E.; Baret, B.; Barrios-Martí, J.; Belias, A.; Berbee, E.; van den Berg, A.; Bertin, V.; Beurthey, S.; van Beveren, V.; Beverini, N.; Biagi, S.; Biagioni, A.; Billault, M.; Bondì, M.; Bormuth, R.; Bouhadef, B.; Bourlis, G.; Bourret, S.; Boutonnet, C.; Bouwhuis, M.; Bozza, C.; Bruijn, R.; Brunner, J.; Buis, E.; Buompane, R.; Busto, J.; Cacopardo, G.; Caillat, L.; Calamai, M.; Calvo, D.; Capone, A.; Caramete, L.; Cecchini, S.; Celli, S.; Champion, C.; Cherubini, S.; Chiarella, V.; Chiarelli, L.; Chiarusi, T.; Circella, M.; Classen, L.; Cobas, D.; Cocimano, R.; Coelho, J. A. B.; Coleiro, A.; Colonges, S.; Coniglione, R.; Cordelli, M.; Cosquer, A.; Coyle, P.; Creusot, A.; Cuttone, G.; D'Amato, C.; D'Amico, A.; D'Onofrio, A.; De Bonis, G.; De Sio, C.; Di Capua, F.; Di Palma, I.; Distefano, C.; Donzaud, C.; Dornic, D.; Dorosti-Hasankiadeh, Q.; Drakopoulou, E.; Drouhin, D.; Durocher, M.; Eberl, T.; Eichie, S.; van Eijk, D.; El Bojaddaini, I.; Elsaesser, D.; Enzenhöfer, A.; Favaro, M.; Fermani, P.; Ferrara, G.; Frascadore, G.; Furini, M.; Fusco, L. A.; Gal, T.; Galatà, S.; Garufi, F.; Gay, P.; Gebyehu, M.; Giacomini, F.; Gialanella, L.; Giordano, V.; Gizani, N.; Gracia, R.; Graf, K.; Grégoire, T.; Grella, G.; Grmek, A.; Guerzoni, M.; Habel, R.; Hallmann, S.; van Haren, H.; Harissopulos, S.; Heid, T.; Heijboer, A.; Heine, E.; Henry, S.; Hernández-Rey, J. J.; Hevinga, M.; Hofestädt, J.; Hugon, C. M. F.; Illuminati, G.; James, C. W.; Jansweijer, P.; Jongen, M.; de Jong, M.; Kadler, M.; Kalekin, O.; Kappes, A.; Katz, U. F.; Keller, P.; Kieft, G.; Kießling, D.; Koffeman, E. N.; Kooijman, P.; Kouchner, A.; Kreter, M.; Kulikovskiy, V.; Lahmann, R.; Lamare, P.; Leisos, A.; Leonora, E.; Clark, M. Lindsey; Liolios, A.; Llorens Alvarez, C. D.; Lo Presti, D.; Löhner, H.; Lonardo, A.; Lotze, M.; Loucatos, S.; Maccioni, E.; Mannheim, K.; Manzali, M.; Margiotta, A.; Margotti, A.; Marinelli, A.; Mariš, O.; Markou, C.; Martínez-Mora, J. A.; Martini, A.; Marzaioli, F.; Mele, R.; Melis, K. W.; Michael, T.; Migliozzi, P.; Migneco, E.; Mijakowski, P.; Miraglia, A.; Mollo, C. M.; Mongelli, M.; Morganti, M.; Moussa, A.; Musico, P.; Musumeci, M.; Nicolau, C. A.; Olcina, I.; Olivetto, C.; Orlando, A.; Orzelli, A.; Pancaldi, G.; Paolucci, A.; Papaikonomou, A.; Papaleo, R.; Păvălaš, G. E.; Peek, H.; Pellegrini, G.; Pellegrino, C.; Perrina, C.; Pfutzner, M.; Piattelli, P.; Pikounis, K.; Poma, G. E.; Popa, V.; Pradier, T.; Pratolongo, F.; Pühlhofer, G.; Pulvirenti, S.; Quinn, L.; Racca, C.; Raffaelli, F.; Randazzo, N.; Real, D.; Resvanis, L.; Reubelt, J.; Riccobene, G.; Rossi, C.; Rovelli, A.; Saldaña, M.; Salvadori, I.; Samtleben, D. F. E.; Sánchez García, A.; Sánchez Losa, A.; Sanguineti, M.; Santangelo, A.; Santonocito, D.; Sapienza, P.; Schimmel, F.; Schmelling, J.; Schnabel, J.; Sciacca, V.; Sedita, M.; Seitz, T.; Sgura, I.; Simeone, F.; Sipala, V.; Spisso, B.; Spurio, M.; Stavropoulos, G.; Steijger, J.; Stellacci, S. M.; Stransky, D.; Taiuti, M.; Tayalati, Y.; Terrasi, F.; Tézier, D.; Theraube, S.; Timmer, P.; Töonnis, C.; Trasatti, L.; Travaglini, R.; Trovato, A.; Tsirigotis, A.; Tzamarias, S.; Tzamariudaki, E.; Vallage, B.; Van Elewyck, V.; Vermeulen, J.; Versari, F.; Vicini, P.; Viola, S.; Vivolo, D.; Volkert, M.; Wiggers, L.; Wilms, J.; de Wolf, E.; Zachariadou, K.; Zani, S.; Zornoza, J. D.; Zúñiga, J.

2016-12-01

The KM3NeT research infrastructure, currently under construction in the Mediterranean Sea, will host neutrino telescopes for the identification of neutrino sources in the Universe and for studies of the neutrino mass hierarchy. These telescopes will house hundreds of thousands of photomultiplier tubes that will have to be operated in a stable and reliable fashion. In this context, the stability of the dark counts has been investigated for photomultiplier tubes with negative high voltage on the photocathode and held in insulating support structures made of 3D printed nylon material. Small gaps between the rigid support structure and the photomultiplier tubes in the presence of electric fields can lead to discharges that produce dark count rates that are highly variable. A solution was found by applying the same insulating varnish as used for the high voltage bases directly to the outside of the photomultiplier tubes. This transparent conformal coating provides a convenient and inexpensive method of insulation.

Defense Facts of Life

DTIC Science & Technology

1980-12-05

planning process. Do the positive attributes of high complexity weapons outweigh their negative qualities’ What effect does our investment in...account for the future consequences of current decisions. We advocate increased budgets because we perceive a growing threat, yet at the same time we...Defense and therefore should not be construed as reflecting an official position of the Department. Thi3 dn .,ment has been opproved for public

Ground-Based High-Power Microwave Decoy Discrimination System.

DTIC Science & Technology

1987-12-23

understanding of plasma instabilities, self-induced magnetic effects , space - charge considerations, production of ion currents, etc. 3.3.4 Cross-Field...breakdown, due to small potential differences. Interaction volumes can therefore be large, avoiding breakdown and space - charge effects (at the price...the interference of the incident and reflected wave, and by the electrostatic forces of the surface (positive) and space charge (negative) trapped in

The Development Of New Space Charge Compensation Methods For Multi-Components Ion Beam Extracted From ECR Ion Source at IMP

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

Ma, L.; Zhao, H.W.; Cao, Y.

2005-03-15

Two new space charge compensation methods developed in IMP are discussed in this paper. There are negative high voltage electrode method (NHVEM) and electronegative charge gas method (EGM). Some valuable experimental data have been achieved, especially using electronegative gas method in O6+ and O7+ dramatic and stable increasing of ion current was observed.

Plasma ARC Welding of High-Performance-Ship Materials

DTIC Science & Technology

1979-05-01

19 REFERENCES .................. ............................ 85 iiii -. -’ - -" -. I LIST OF FIGURES Page I - Comparison of PAW and GTAW ...tungsten-arc- welding ( GTAW ) process. Both processes employ an inert-gas-shielded non- consumable tungsten electrode, as shown in Figure 1. In genernl, both...piece acts as the cathode (ground or negative). However, both PAW and GTAW can be and have been, used with direct-current reverse polarity and with

Skin blood flow with elastic compressive extravehicular activity space suit.

PubMed

Tanaka, Kunihiko; Gotoh, Taro M; Morita, Hironobu; Hargens, Alan R

2003-10-01

During extravehicular activity (EVA), current space suits are pressurized with 100% oxygen at approximately 222 mmHg. A tight elastic garment, or mechanical counter pressure (MCP) suit that generates pressure by compression, may have several advantages over current space suit technology. In this study, we investigated local microcirculatory effects produced with negative ambient pressure with an MCP sleeve. The MCP glove and sleeve generated pressures similar to the current space suit. MCP remained constant during negative pressure due to unchanged elasticity of the material. Decreased skin capillary blood flow and temperature during MCP compression was counteracted by greater negative pressure or a smaller pressure differential.

Neural correlates of processing negative and sexually arousing pictures.

PubMed

Bailey, Kira; West, Robert; Mullaney, Kellie M

2012-01-01

Recent work has questioned whether the negativity bias is a distinct component of affective picture processing. The current study was designed to determine whether there are different neural correlates of processing positive and negative pictures using event-related brain potentials. The early posterior negativity and late positive potential were greatest in amplitude for erotic pictures. Partial Least Squares analysis revealed one latent variable that distinguished erotic pictures from neutral and positive pictures and another that differentiated negative pictures from neutral and positive pictures. The effects of orienting task on the neural correlates of processing negative and erotic pictures indicate that affective picture processing is sensitive to both stimulus-driven, and attentional or decision processes. The current data, together with other recent findings from our laboratory, lead to the suggestion that there are distinct neural correlates of processing negative and positive stimuli during affective picture processing.

Neural Correlates of Processing Negative and Sexually Arousing Pictures

PubMed Central

Bailey, Kira; West, Robert; Mullaney, Kellie M.

2012-01-01

Recent work has questioned whether the negativity bias is a distinct component of affective picture processing. The current study was designed to determine whether there are different neural correlates of processing positive and negative pictures using event-related brain potentials. The early posterior negativity and late positive potential were greatest in amplitude for erotic pictures. Partial Least Squares analysis revealed one latent variable that distinguished erotic pictures from neutral and positive pictures and another that differentiated negative pictures from neutral and positive pictures. The effects of orienting task on the neural correlates of processing negative and erotic pictures indicate that affective picture processing is sensitive to both stimulus-driven, and attentional or decision processes. The current data, together with other recent findings from our laboratory, lead to the suggestion that there are distinct neural correlates of processing negative and positive stimuli during affective picture processing. PMID:23029071

2D negative capacitance field-effect transistor with organic ferroelectrics.

PubMed

Zhang, Heng; Chen, Yan; Ding, Shijin; Wang, Jianlu; Bao, Wenzhong; Zhang, David Wei; Zhou, Peng

2018-06-15

In the past fifty years, complementary metal-oxide-semiconductor integrated circuits have undergone significant development, but Moore's law will soon come to an end. In order to break through the physical limit of Moore's law, 2D materials have been widely used in many electronic devices because of their high mobility and excellent mechanical flexibility. And the emergence of a negative capacitance field-effect transistor (NCFET) could not only break the thermal limit of conventional devices, but reduce the operating voltage and power consumption. This paper demonstrates a 2D NCFET that treats molybdenum disulfide as a channel material and organic P(VDF-TrFE) as a gate dielectric directly. This represents a new attempt to prepare NCFETs and produce flexible electronic devices. It exhibits a 10^6 on-/off-current ratio. And the minimum subthreshold swing (SS) of the 21 mV/decade and average SS of the 44 mV/decade in four orders of magnitude of drain current can also be observed at room temperature of 300 K.

The extraction of negative carbon ions from a volume cusp ion source

NASA Astrophysics Data System (ADS)

Melanson, Stephane; Dehnel, Morgan; Potkins, Dave; McDonald, Hamish; Hollinger, Craig; Theroux, Joseph; Martin, Jeff; Stewart, Thomas; Jackle, Philip; Philpott, Chris; Jones, Tobin; Kalvas, Taneli; Tarvainen, Olli

2017-08-01

Acetylene and carbon dioxide gases are used in a filament-powered volume-cusp ion source to produce negative carbon ions for the purpose of carbon implantation for gettering applications. The beam was extracted to an energy of 25 keV and the composition was analyzed with a spectrometer system consisting of a 90° dipole magnet and a pair of slits. It is found that acetylene produces mostly C2- ions (up to 92 µA), while carbon dioxide produces mostly O- with only trace amounts of C-. Maximum C2- current was achieved with 400 W of arc power and, the beam current and composition were found to be highly dependent on the pressure in the source. The beam properties as a function of source settings are analyzed, and plasma properties are measured with a Langmuir probe. Finally, we describe testing of a new RF H- ion source, found to produce more than 6 mA of CW H- beam.

2D negative capacitance field-effect transistor with organic ferroelectrics

NASA Astrophysics Data System (ADS)

Zhang, Heng; Chen, Yan; Ding, Shijin; Wang, Jianlu; Bao, Wenzhong; Zhang, David Wei; Zhou, Peng

2018-06-01

In the past fifty years, complementary metal-oxide-semiconductor integrated circuits have undergone significant development, but Moore’s law will soon come to an end. In order to break through the physical limit of Moore’s law, 2D materials have been widely used in many electronic devices because of their high mobility and excellent mechanical flexibility. And the emergence of a negative capacitance field-effect transistor (NCFET) could not only break the thermal limit of conventional devices, but reduce the operating voltage and power consumption. This paper demonstrates a 2D NCFET that treats molybdenum disulfide as a channel material and organic P(VDF-TrFE) as a gate dielectric directly. This represents a new attempt to prepare NCFETs and produce flexible electronic devices. It exhibits a 106 on-/off-current ratio. And the minimum subthreshold swing (SS) of the 21 mV/decade and average SS of the 44 mV/decade in four orders of magnitude of drain current can also be observed at room temperature of 300 K.

Near-earth magnetic disturbance in total field at high latitudes. I - Summary of data from Ogo 2, 4, and 6. II - Interpretation of data from Ogo 2, 4, and 6

NASA Technical Reports Server (NTRS)

Langel, R. A.

1974-01-01

A complete survey of the near-earth magnetic field magnitude was carried out by the Polar Orbiting Geophysical Observatories (Ogo 2, 4, and 6). The average properties of variations in total magnetic field strength at invariant latitudes greater than 55 deg are given. Data from all degrees of magnetic disturbance are included, the emphasis being on periods when Kp = 2- to 3+. Although individual satellite passes at low altitudes confirm the existence of electrojet currents, neither individual satellite passes nor contours of average delta B are consistent with latitudinally narrow electrojet currents as the principal source of delta B at the satellite. The total field variations at the satellite form a region of positive delta B between about 2200 and 1000 MLT and a region of negative delta B between about 1000 and 2200 MLT. The ratio of delta B magnitudes in these positive and negative regions is variable.

The eye of the begetter: predicting infant attachment disorganization from women's prenatal interpretations of infant facial expressions.

PubMed

Bernstein, Rosemary E; Tenedios, Catherine M; Laurent, Heidemarie K; Measelle, Jeffery R; Ablow, Jennifer C

2014-01-01

Infant-caregiver attachment disorganization has been linked to many long-term negative psychosocial outcomes. While various prevention programs appear to be effective in preventing disorganized attachment, methods currently used to identify those at risk are unfortunately either overly general or impractical. The current investigation tested whether women's prenatal biases in identifying infant expressions of emotion--tendencies previously shown to relate to some of the maternal variables associated with infant attachment, including maternal traumatization, trauma symptoms, and maternal sensitivity--could predict infant attachment classification at 18 months postpartum. Logistic regression analyses revealed that together with women's adult history of high betrayal traumatization, response concordance with a normative reference sample in labeling infant expressions as negatively valenced, and the number of infant facial expressions that participants classified as "sad" and "angry" predicted subsequent infant attachment security versus disorganization. Implications for screening and prevention are discussed. © 2014 Michigan Association for Infant Mental Health.

[Long-term care in Europe. Challenges and strategies in nursing staff management].

PubMed

Kuhlmann, E; Larsen, C

2013-08-01

Across Europe, long-term care (LTC) is one of the most challenging areas of social policy. Despite a growing awareness of the problems and improved data, current institutional reforms are an ineffective response to demographic change. This article aims to provide an overview of the challenges of future nursing and care staff in LTC in Europe, and to discuss the German case in a wider European context. We focus on the nursing workforce and on the link between current and prospective analyses on the demand and offer of LTC services and LTC professionals/nursing staff. We draw on a secondary analysis of the literature and public statistics, especially OECD data. The European comparison shows a high variation in the future demand for LTC. In Germany, a number of problematic trends create a negative scenario: the growing demand for LTC meets with a decrease in nursing staff on the supply side. We conclude by suggesting intervention strategies that may reduce this negative scenario.

A Robust High Current Density Electron Gun

NASA Astrophysics Data System (ADS)

Mako, F.; Peter, W.; Shiloh, J.; Len, L. K.

1996-11-01

Proof-of-principle experiments are proposed to validate a new concept for a robust, high-current density Pierce electron gun (RPG) for use in klystrons and high brightness electron sources for accelerators. This rugged, long-life electron gun avoids the difficulties associated with plasma cathodes, thermionic emitters, and field emission cathodes. The RPG concept employs the emission of secondary electrons in a transmission mode as opposed to the conventional mode of reflection, i.e., electrons exit from the back face of a thin negative electron affinity (NEA) material, and in the same direction as the incident beam. Current amplification through one stage of a NEA material could be over 50 times. The amplification is accomplished in one or more stages consisting of one primary emitter and one or more secondary emitters. The primary emitter is a low current density robust emitter (e.g., thoriated tungsten). The secondary emitters are thin NEA electrodes which emit secondary electrons in the same direction as the incident beam. Specific application is targeted for a klystron gun to be used by SLAC with a cold cathode at 30-40 amps/cm^2 output from the secondary emission stage, a ~2 μs pulse length, and ~200 pulses/second.

Impact of negative capacitance effect on Germanium Double Gate pFET for enhanced immunity to interface trap charges

NASA Astrophysics Data System (ADS)

Bansal, Monika; Kaur, Harsupreet

2018-05-01

In this work, a comprehensive drain current model has been developed for long channel Negative Capacitance Germanium Double Gate p-type Field Effect Transistor (NCGe-DG-pFET) by using 1-D Poisson's equation and Landau-Khalatnikov equation. The model takes into account interface trap charges and by using the derived model various parameters such as surface potential, gain, gate capacitance, subthreshold swing, drain current, transconductance, output conductance and Ion/Ioff ratio have been obtained and it is demonstrated that by incorporating ferroelectric material as gate insulator with Ge-channel, subthreshold swing values less than 60 mV/dec can be achieved along with improved gate controllability and current drivability. Further, to critically analyze the advantages offered by NCGe-DG-pFET, a detailed comparison has been done with Germanium Double Gate p-type Field Effect Transistor (Ge-DG-pFET) and it is shown that NCGe-DG-pFET exhibits high gain, enhanced transport efficiency in channel, very less or negligible degradation in device characteristics due to interface trap charges as compared to Ge-DG-pFET. The analytical results so obtained show good agreement with simulated results obtained from Silvaco ATLAS TCAD tool.

Cannabis use during a voluntary quit attempt: an analysis from ecological momentary assessment.

PubMed

Buckner, Julia D; Zvolensky, Michael J; Ecker, Anthony H

2013-10-01

There is little research that has sought to identify factors related to quit success and failure among cannabis users. The current study examined affective, cognitive, and situational factors related to cannabis use among current cannabis users undergoing a voluntary, self-guided quit attempt. The sample consisted of 30 (33% female) current cannabis users, 84% of whom evinced a current cannabis use disorder. Ecological momentary assessment was used to collect multiple daily ratings of cannabis withdrawal, negative affect, peer cannabis use, reasons for use, and successful coping strategies over two weeks. Findings from generalized linear models indicated that cannabis withdrawal and positive and negative affect were significantly higher during cannabis use than non-use episodes. Additionally, when negative and positive affect were entered simultaneously, negative affect, but not positive affect, remained significantly related to use. Participants were significantly more likely to use in social situations than when alone. When participants were in social situations, they were significantly more likely to use if others were using. Participants tended to use more behavioral than cognitive strategies to abstain from cannabis. The most common reason for use was to cope with negative affect. Overall, these novel findings indicate that cannabis withdrawal, affect (especially negative affect), and peer use play important roles in cannabis use among self-quitters. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

A threshold effect for spacecraft charging

NASA Technical Reports Server (NTRS)

Olsen, R. C.

1983-01-01

The borderline case between no charging and large (kV) negative potentials for eclipse charging events on geosynchronous satellites is investigated, and the dependence of this transition on a threshold energy in the ambient plasma is examined. Data from the Applied Technology Satellite 6 and P78-2 (SCATHA) show that plasma sheet fluxes must extend above 10 keV for these satellites to charge in eclipse. The threshold effect is a result of the shape of the normal secondary yield curve, in particular the high energy crossover, where the secondary yield drops below 1. It is found that a large portion of the ambient electron flux must exceed this energy for a negative current to exist.

Carbon Nanotube Vacuum Gauges Utilizing Long, Dissipative Tubes

NASA Technical Reports Server (NTRS)

Kaul, Anupama B.; Manohara, Harish M.

2008-01-01

CNT Vacuum Gauges: a) have a broad range of pressure response from 760 - 10(exp -6) Torr. b) have current changes approx. 100's nA in high vacuum regime (10(exp -6) Torr) and sensitivity increases with power and substrate removal. c) have a negative dR/dT (TCR negative) where a thermal hopping energy E(sub a) was determined to be approx. 40 meV. d) have compatible fabrication requirements for their integration with micromachined structures. e) can be operated at low power (nW - micro-W). f) have an active device region footprint of < 10 sq microns. g) are non-intrusive due to small size and passive operation.

Epidemiology and antimicrobial susceptibility of Gram-negative aerobic bacteria causing intra-abdominal infections during 2010-2011.

PubMed

Hawser, Stephen; Hoban, Daryl J; Badal, Robert E; Bouchillon, Samuel K; Biedenbach, Douglas; Hackel, Meredith; Morrissey, Ian

2015-02-01

The study for monitoring antimicrobial resistance trends (SMART) surveillance program monitors the epidemiology and trends in antibiotic resistance of intra-abdominal pathogens to currently used therapies. The current report describes such trends during 2010-2011. A total of 25,746 Gram-negative clinical isolates from intra-abdominal infections were collected and classified as hospital-associated (HA) if the hospital length of stay (LOS) at the time of specimen collection was ≥48 hours, community-associated (CA) if LOS at the time of specimen collection was <48 hours, or unknown (no designation given by participating centre). A total of 92 different species were collected of which the most common was Escherichia coli: 39% of all isolates in North America to 55% in Africa. Klebsiella pneumoniae was the second most common pathogen: 11% of all isolates from Europe to 19% of all isolates from Asia. Isolates were from multiple intra-abdominal sources of which 32% were peritoneal fluid, 20% were intra-abdominal abscesses, and 16.5% were gall bladder infections. Isolates were further classified as HA (55% of all isolates), CA (39% of all isolates), or unknown (6% of all isolates). The most active antibiotics tested were imipenem, ertapenem, amikacin, and piperacillin-tazobactam. Resistance rates to all other antibiotics tested were high. Considering the current data set and high-level resistance of intra-abdominal pathogens to various antibiotics, further monitoring of the epidemiology of intra-abdominal infections and their susceptibility to antibiotics through SMART is warranted.

Multiclass Classification of Agro-Ecological Zones for Arabica Coffee: An Improved Understanding of the Impacts of Climate Change.

PubMed

Bunn, Christian; Läderach, Peter; Pérez Jimenez, Juan Guillermo; Montagnon, Christophe; Schilling, Timothy

2015-01-01

Cultivation of Coffea arabica is highly sensitive to and has been shown to be negatively impacted by progressive climatic changes. Previous research contributed little to support forward-looking adaptation. Agro-ecological zoning is a common tool to identify homologous environments and prioritize research. We demonstrate here a pragmatic approach to describe spatial changes in agro-climatic zones suitable for coffee under current and future climates. We defined agro-ecological zones suitable to produce arabica coffee by clustering geo-referenced coffee occurrence locations based on bio-climatic variables. We used random forest classification of climate data layers to model the spatial distribution of these agro-ecological zones. We used these zones to identify spatially explicit impact scenarios and to choose locations for the long-term evaluation of adaptation measures as climate changes. We found that in zones currently classified as hot and dry, climate change will impact arabica more than those that are better suited to it. Research in these zones should therefore focus on expanding arabica's environmental limits. Zones that currently have climates better suited for arabica will migrate upwards by about 500m in elevation. In these zones the up-slope migration will be gradual, but will likely have negative ecosystem impacts. Additionally, we identified locations that with high probability will not change their climatic characteristics and are suitable to evaluate C. arabica germplasm in the face of climate change. These locations should be used to investigate long term adaptation strategies to production systems.

Temperature responsive transmitter

NASA Technical Reports Server (NTRS)

Kleinberg, Leonard L. (Inventor)

1987-01-01

A temperature responsive transmitter is provided in which frequency varies linearly with temperature. The transmitter includes two identically biased transistors connected in parallel. A capacitor, which reflects into the common bases to generate negative resistance effectively in parallel with the capacitor, is connected to the common emitters. A crystal is effectively in parallel with the capacitor and the negative resistance. Oscillations occur if the magnitude of the absolute value of the negative resistance is less than the positive resistive impedance of the capacitor and the inductance of the crystal. The crystal has a large linear temperature coefficient and a resonant frequency which is substantially less than the gain-bandwidth product of the transistors to ensure that the crystal primarily determines the frequency of oscillation. A high-Q tank circuit having an inductor and a capacitor is connected to the common collectors to increase the collector current flow which in turn enhances the radiation of the oscillator frequency by the inductor.

Screening for human papillomavirus, cervical cytological abnormalities and associated risk factors in HIV-positive and HIV-negative women in Rwanda.

PubMed

Mukanyangezi, M F; Sengpiel, V; Manzi, O; Tobin, G; Rulisa, S; Bienvenu, E; Giglio, D

2018-02-01

Cervical cancer is the major cause of death from cancer in Africa. We wanted to assess the prevalence of human papillomavirus (HPV) infections and associated risk factors and to determine whether HPV testing could serve as a screening method for squamous intraepithelial lesions (SILs) in Rwanda. We also wanted to obtain a broader understanding of the underlying risk factors for the establishment of HPV infection in Rwanda. A total of 206 HIV-positive women, 172 HIV-negative women and 22 women with unknown HIV status were recruited at the University Teaching Hospitals of Kigali (UTHK) and of Butare (UTHB) in Rwanda. Participants underwent an interview, cervical sampling for a Thinprep Pap test and a screening test analysing 37 HPV strains. Only 27% of HIV-positive women and 7% of HIV-negative women had been screened for cervical cancer before. HPV16 and HPV52 were the most common HPV strains. HIV-positive women were more commonly infected with high-risk (HR) HPV and multitype HPV than HIV-negative women. The sensitivity was 78% and the specificity 87% to detect high-grade SIL (HSIL) with HPV screening. Among HIV-negative women, being divorced was positively associated with HR-HPV infection, while hepatitis B, Trichomonas vaginalis infection and HR-HPV infection were factors positively associated with SILs. Ever having had gonorrhoea was positively associated with HR-HPV infection among HIV-positive women. HR-HPV infection and the number of live births were positively associated with SILs. The currently used quadrivalent vaccine may be insufficient to give satisfactory HPV coverage in Rwanda. HPV Screening may be effective to identify women at risk of developing cervical cancer, particularly if provided to high-risk patients. © 2017 British HIV Association.

Suppression of turbulent transport in NSTX internal transport barriers

NASA Astrophysics Data System (ADS)

Yuh, Howard

2008-11-01

Electron transport will be important for ITER where fusion alphas and high-energy beam ions will primarily heat electrons. In the NSTX, internal transport barriers (ITBs) are observed in reversed (negative) shear discharges where diffusivities for electron and ion thermal channels and momentum are reduced. While neutral beam heating can produce ITBs in both electron and ion channels, High Harmonic Fast Wave (HHFW) heating can produce electron thermal ITBs under reversed magnetic shear conditions without momentum input. Interestingly, the location of the electron ITB does not necessarily match that of the ion ITB: the electron ITB correlates well with the minimum in the magnetic shear determined by Motional Stark Effect (MSE) [1] constrained equilibria, whereas the ion ITB better correlates with the maximum ExB shearing rate. Measured electron temperature gradients can exceed critical linear thresholds for ETG instability calculated by linear gyrokinetic codes in the ITB confinement region. The high-k microwave scattering diagnostic [2] shows reduced local density fluctuations at wavenumbers characteristic of electron turbulence for discharges with strongly negative magnetic shear versus weakly negative or positive magnetic shear. Fluctuation reductions are found to be spatially and temporally correlated with the local magnetic shear. These results are consistent with non-linear gyrokinetic simulations predictions showing the reduction of electron transport in negative magnetic shear conditions despite being linearly unstable [3]. Electron transport improvement via negative magnetic shear rather than ExB shear highlights the importance of current profile control in ITER and future devices. [1] F.M. Levinton, H. Yuh et al., PoP 14, 056119 [2] D.R. Smith, E. Mazzucato et al., RSI 75, 3840 [3] Jenko, F. and Dorland, W., PRL 89 225001

Effects of Gymnastics Activities on Bone Accrual during Growth: A Systematic Review

PubMed Central

Jürimäe, Jaak; Gruodyte-Raciene, Rita; Baxter-Jones, Adam D. G.

2018-01-01

The amount of bone gained during childhood and adolescence impacts greatly on lifetime skeletal health. The purpose of this review is to summarize current evidence of the effects of gymnastics activities on bone mineral accrual during growth and to describe possible factors that influence bone mineral gains. The PubMed and SportDiscus databases were searched, and a total of 24 articles met the selection criteria and were included in this review. Artistic and rhythmic gymnasts presented higher bone mineral density and content values compared to untrained controls, despite possible negative effects associated with hormonal levels, dietary restrictions and body fat. The results suggest that gymnasts had similar bone turnover values compared to untrained controls. High-intensity mechanical loading of gymnastics activity appears to increase bone development and counterbalance negative effects, such as later pubertal development, lower body fat mass and lower hormone levels. In conclusion, gymnasts present higher bone mineral values in comparison with untrained controls. The osteogenic effect of gymnastics athletic activity has a positive influence on bone mineral accrual and overcomes the possible negative influence of high athletic activity that may cause negative energy balance and low body fat mass which are associated with lower bone accrual. Key points Children and adolescent gymnasts present higher bone mineral density and content values compared to untrained controls, despite a variety of possible negative factors. Gymnastics activity with high-impact mechanical loading appears to be especially osteogenic to achieve maximum possible peak bone accrual during growth and maturation. Skeletal benefits of gymnastics activity in childhood are maintained for several years after retirement from gymnastics trainings in young adulthood. PMID:29769826

Principles and methods for ensuring safe operation of high-rise buildings

NASA Astrophysics Data System (ADS)

Korol, Oleg; Kustikova, Yuliya

2018-03-01

The purpose of monitoring the technical condition of high-rise buildings is to prevent possible negative situations leading to significant socio-economic losses by timely warning of the emergence of such situations. To achieve this goal, it is necessary to solve the following main tasks, such as: identifying the time and place of origin and development of negative processes that lead to the emergence of an emergency situation; analysis of the possible development of the situation in time; development of management decisions; formation and submission of warning signals; obtaining new knowledge about the operation of the object, the factors of influence on this object, the speed of development of destructive processes. When solving the above problems, an important role is played by constructing an adequate mathematical model of the object, the parameters of which should be calibrated according to the current monitoring results.

Runaway breakdown and hydrometeors in lightning initiation.

PubMed

Gurevich, A V; Karashtin, A N

2013-05-03

The particular electric pulse discharges are observed in thunderclouds during the initiation stage of negative cloud-to-ground lightning. The discharges are quite different from conventional streamers or leaders. A detailed analysis reveals that the shape of the pulses is determined by the runaway breakdown of air in the thundercloud electric field initiated by extensive atmospheric showers (RB-EAS). The high amplitude of the pulse electric current is due to the multiple microdischarges at hydrometeors stimulated and synchronized by the low-energy electrons generated in the RB-EAS process. The series of specific pulse discharges leads to charge reset from hydrometeors to the free ions and creates numerous stretched ion clusters, both positive and negative. As a result, a wide region in the thundercloud with a sufficiently high fractal ion conductivity is formed. The charge transport by ions plays a decisive role in the lightning leader preconditioning.

[Primary cervical cancer screening].

PubMed

Vargas-Hernández, Víctor Manuel; Vargas-Aguilar, Víctor Manuel; Tovar-Rodríguez, José María

2015-01-01

Cervico-uterine cancer screening with cytology decrease incidence by more than 50%. The cause of this cancer is the human papilloma virus high risk, and requires a sensitive test to provide sufficient sensitivity and specificity for early detection and greater interval period when the results are negative. The test of the human papilloma virus high risk, is effective and safe because of its excellent sensitivity, negative predictive value and optimal reproducibility, especially when combined with liquid-based cytology or biomarkers with viral load, with higher sensitivity and specificity, by reducing false positives for the detection of cervical intraepithelial neoplasia grade 2 or greater injury, with excellent clinical benefits to cervical cancer screening and related infection of human papilloma virus diseases, is currently the best test for early detection infection of human papillomavirus and the risk of carcinogenesis. Copyright © 2015 Academia Mexicana de Cirugía A.C. Published by Masson Doyma México S.A. All rights reserved.

The Role of Academic Motivation in High School Students’ Current and Lifetime Alcohol Consumption: Adopting a Self-Determination Theory Perspective*

PubMed Central

Wormington, Stephanie V.; Anderson, Kristen G.; Corpus, Jennifer Henderlong

2011-01-01

Objective: The current study investigated the relationship between different types of academic motives—specifically, intrinsic motivation, introjected regulation, and external regulation—and high school students' current and lifetime alcohol consumption. Method: One thousand sixty-seven high school students completed measures of academic motivation, other school-related factors, and lifetime and current alcohol consumption. Results: Using structural equation modeling, different types of motivation and school-related factors were differentially related to student drinking. Specifically, intrinsic motivation was negatively related to lifetime and current alcohol consumption. External regulation, on the other hand, was positively associated with current drinking. Grade point average was the only school-related factor related to student alcohol use. Conclusions: These findings suggest that motivation is an important construct to consider in predicting students’ alcohol use, even when other more commonly studied educational variables are considered. In addition, it supports the adoption of a motivation framework that considers different types of motivation in understanding the relationship between academic motivation and alcohol use. Suggestions for incorporating the self-determination model of motivation into studies of alcohol and substance use, as well as potential impacts on intervention efforts, are discussed. In particular, it may be important to foster only certain types of motivation, rather than all types of academically-focused motives, in efforts to deter alcohol use. PMID:22051210

The role of academic motivation in high school students' current and lifetime alcohol consumption: adopting a self-determination theory perspective.

PubMed

Wormington, Stephanie V; Anderson, Kristen G; Corpus, Jennifer Henderlong

2011-11-01

The current study investigated the relationship between different types of academic motives-specifically, intrinsic motivation, introjected regulation, and external regulation-and high school students' current and lifetime alcohol consumption. One thousand sixty-seven high school students completed measures of academic motivation, other school-related factors, and lifetime and current alcohol consumption. Using structural equation modeling, different types of motivation and school-related factors were differentially related to student drinking. Specifically, intrinsic motivation was negatively related to lifetime and current alcohol consumption. External regulation, on the other hand, was positively associated with current drinking. Grade point average was the only school-related factor related to student alcohol use. These findings suggest that motivation is an important construct to consider in predicting students' alcohol use, even when other more commonly studied educational variables are considered. In addition, it supports the adoption of a motivation framework that considers different types of motivation in understanding the relationship between academic motivation and alcohol use. Suggestions for incorporating the self-determination model of motivation into studies of alcohol and substance use, as well as potential impacts on intervention efforts, are discussed. In particular, it may be important to foster only certain types of motivation, rather than all types of academically-focused motives, in efforts to deter alcohol use.

Modification of the argon stripping target of the tandem accelerator.

PubMed

Makarov, A; Ostreinov, Yu; Taskaev, S; Vobly, P

2015-12-01

The tandem accelerator with vacuum insulation has been proposed and developed in Budker Institute of Nuclear Physics. Negative hydrogen ions are accelerated by the positive 1MV potential of the high-voltage electrode, converted into protons in the gas stripping target inside the electrode, and then protons are accelerated again by the same potential. A stationary proton beam with 2 MeV energy, 1.6 mA current, 0.1% energy monochromaticity, and 0.5% current stability is obtained now. To conduct Boron Neutron Capture Therapy it is planned to increase the proton beam current to at least 3 mA. The paper presents the results of experimental studies clarifying the reasons for limiting the current, and gives suggestions for modifying the gas stripping target in order to increase the proton beam current along with the stability of the accelerator. Copyright © 2015 Elsevier Ltd. All rights reserved.

A new deflection technique applied to an existing scheme of electrostatic accelerator for high energy neutral beam injection in fusion reactor devices

NASA Astrophysics Data System (ADS)

Pilan, N.; Antoni, V.; De Lorenzi, A.; Chitarin, G.; Veltri, P.; Sartori, E.

2016-02-01

A scheme of a neutral beam injector (NBI), based on electrostatic acceleration and magneto-static deflection of negative ions, is proposed and analyzed in terms of feasibility and performance. The scheme is based on the deflection of a high energy (2 MeV) and high current (some tens of amperes) negative ion beam by a large magnetic deflector placed between the Beam Source (BS) and the neutralizer. This scheme has the potential of solving two key issues, which at present limit the applicability of a NBI to a fusion reactor: the maximum achievable acceleration voltage and the direct exposure of the BS to the flux of neutrons and radiation coming from the fusion reactor. In order to solve these two issues, a magnetic deflector is proposed to screen the BS from direct exposure to radiation and neutrons so that the voltage insulation between the electrostatic accelerator and the grounded vessel can be enhanced by using compressed SF6 instead of vacuum so that the negative ions can be accelerated at energies higher than 1 MeV. By solving the beam transport with different magnetic deflector properties, an optimum scheme has been found which is shown to be effective to guarantee both the steering effect and the beam aiming.

A new deflection technique applied to an existing scheme of electrostatic accelerator for high energy neutral beam injection in fusion reactor devices.

PubMed

Pilan, N; Antoni, V; De Lorenzi, A; Chitarin, G; Veltri, P; Sartori, E

2016-02-01

A scheme of a neutral beam injector (NBI), based on electrostatic acceleration and magneto-static deflection of negative ions, is proposed and analyzed in terms of feasibility and performance. The scheme is based on the deflection of a high energy (2 MeV) and high current (some tens of amperes) negative ion beam by a large magnetic deflector placed between the Beam Source (BS) and the neutralizer. This scheme has the potential of solving two key issues, which at present limit the applicability of a NBI to a fusion reactor: the maximum achievable acceleration voltage and the direct exposure of the BS to the flux of neutrons and radiation coming from the fusion reactor. In order to solve these two issues, a magnetic deflector is proposed to screen the BS from direct exposure to radiation and neutrons so that the voltage insulation between the electrostatic accelerator and the grounded vessel can be enhanced by using compressed SF6 instead of vacuum so that the negative ions can be accelerated at energies higher than 1 MeV. By solving the beam transport with different magnetic deflector properties, an optimum scheme has been found which is shown to be effective to guarantee both the steering effect and the beam aiming.

An examination of the perceptions of social network characteristics associated with grandiose and vulnerable narcissism.

PubMed

Lamkin, Joanna; Clifton, Allan; Campbell, W Keith; Miller, Joshua D

2014-04-01

Two dimensions of narcissism exist, grandiose and vulnerable, which are thought to be associated with distinctly different patterns of interpersonal behavior. Social network analysis is a way of quantifying and analyzing interpersonal interactions that may prove useful for characterizing the networks associated with these narcissism dimensions. In the current study, participants (N = 148) completed scales assessing both narcissism dimensions and a measure of the five-factor model of personality. Egocentric network information about participants' 30 closest friends and family members (i.e., "alters") was also obtained. Both narcissism dimensions were characterized by negative perceptions of the individuals who comprise one's social networks, and many of these relations were mediated by individuals' higher levels of antagonism. Grandiose narcissism also interacted with alter centrality (i.e., importance to the network) such that individuals low on grandiose narcissism were less likely to perceive central alters in a negative light and were more attuned to central alters than were individuals high on grandiose narcissism. Overall, both narcissism dimensions were associated with perceiving one's overall social environment negatively because of the high levels of antagonism that characterize both narcissism dimensions. Individuals high on grandiose narcissism, however, appear to be more insensitive to the relative importance of individuals in their social networks. PsycINFO Database Record (c) 2014 APA, all rights reserved

Neighborhood cohesion and daily well-being: Results from a diary study

PubMed Central

Robinette, Jennifer W.; Charles, Susan T.; Mogle, Jacqueline A.; Almeida, David M.

2013-01-01

Neighborly cohesiveness has documented benefits for health. Furthermore, high perceived neighborhood cohesion offsets the adverse health effects of neighborhood socioeconomic adversity. One potential way neighborhood cohesion influences health is through daily stress processes. The current study uses participants (n = 2022, age 30–84 years) from The Midlife in the United States II and the National Study of Daily Experiences II, collected between 2004–2006, to examine this hypothesis using a within-person, daily diary design. We predicted that people who perceive high neighborhood cohesion are exposed to fewer daily stressors, such as interpersonal arguments, lower daily physical symptoms and negative affect, and higher daily positive affect. We also hypothesized that perceptions of neighborhood cohesion buffer declines in affective and physical well-being on days when daily stressors do occur. Results indicate that higher perceived neighborhood cohesion predicts fewer self-reported daily stressors, higher positive affect, lower negative affect, and fewer physical health symptoms. High perceived neighborhood cohesion also buffers the effects of daily stressors on negative affect, even after adjusting for other sources of social support. Results from the present study suggest interventions focusing on neighborhood cohesion may result in improved well-being and may minimize the adverse effect of daily stressors. PMID:24034965

High efficiency and enhanced ESD properties of UV LEDs by inserting p-GaN/p-AlGaN superlattice

NASA Astrophysics Data System (ADS)

Huang, Yong; Li, PeiXian; Yang, Zhuo; Hao, Yue; Wang, XiaoBo

2014-05-01

Significantly improved electrostatic discharge (ESD) properties of InGaN/GaN-based UV light-emitting diode (LED) with inserting p-GaN/p-AlGaN superlattice (p-SLs) layers (instead of p-AlGaN single layer) between multiple quantum wells and Mg-doped GaN layer are reported. The pass yield of the LEDs increased from 73.53% to 93.81% under negative 2000 V ESD pulses. In addition, the light output power (LOP) and efficiency droop at high injection current were also improved. The mechanism of the enhanced ESD properties was then investigated. After excluding the effect of capacitance modulation, high-resolution X-ray diffraction (XRD) and atomic force microscope (AFM) measurements demonstrated that the dominant mechanism of the enhanced ESD properties is the material quality improved by p-SLs, which indicated less leakage paths, rather than the current spreading improved by p-SLs.

High-voltage, high-power, solid-state remote power controllers for aerospace applications

NASA Technical Reports Server (NTRS)

Sturman, J. C.

1985-01-01

Two general types of remote power controller (RPC) that combine the functions of a circuit breaker and a switch were developed for use in direct-current (dc) aerospace systems. Power-switching devices used in these designs are the relatively new gate-turnoff thyristor (GTO) and poweer metal-oxide-semiconductor field-effect transistors (MOSFET). The various RPC's can switch dc voltages to 1200 V and currents to 100 A. Seven different units were constructed and subjected to comprehensive laboratory and thermal vacuum testing. Two of these were dual units that switch both positive and negative voltages simultaneously. The RPC's using MOSFET's have slow turnon and turnoff times to limit voltage spiking from high di/dt. The GTO's have much faster transition times. All RPC's have programmable overload tripout and microsecond tripout for large overloads. The basic circuits developed can be used to build switchgear limited only by the ratings of the switching device used.

Evidence for specificity of the impact of punishment on error-related brain activity in high versus low trait anxious individuals.

PubMed

Meyer, Alexandria; Gawlowska, Magda

2017-10-01

A previous study suggests that when participants were punished with a loud noise after committing errors, the error-related negativity (ERN) was enhanced in high trait anxious individuals. The current study sought to extend these findings by examining the ERN in conditions when punishment was related and unrelated to error commission as a function of individual differences in trait anxiety symptoms; further, the current study utilized an electric shock as an aversive unconditioned stimulus. Results confirmed that the ERN was increased when errors were punished among high trait anxious individuals compared to low anxious individuals; this effect was not observed when punishment was unrelated to errors. Findings suggest that the threat-value of errors may underlie the association between certain anxious traits and punishment-related increases in the ERN. Copyright © 2017 Elsevier B.V. All rights reserved.

Direct current H- source for the medicine accelerator (invited)

NASA Astrophysics Data System (ADS)

Belchenko, Yu.; Savkin, V.

2004-05-01

A compact cw hydrogen negative ion source having reliable operation and a simplified maintenance is developed at Budker Institute of Nuclear Physics for a tandem accelerator of boron capture neutron therapy installation. The source uses a Penning discharge with a hydrogen and cesium feed through the hollows in the cathodes. Discharge voltage is about 60-80 V, current 9 A, hydrogen pressure 4-5 Pa, magnetic field 0.05-0.1 T, and cesium seed <1 mg/h. Negative ions are mainly produced on the cesiated anode surface due to conversion of hydrogen atoms. An optimal anode temperature is 250-350 °C. Negative ion beam current is directly proportional to the discharge current and to the emission hole area. A triode system for the beam extraction and acceleration system is used. The flux of accompanying extracted electrons was decreased by filtering in the transverse magnetic field. This electron flux was intercepted to the special electrode, biased at 4 kV potential with respect to the anode. Source stable cw operation for several hour runs was multiply tested. A H- ion beam with current up to 8 mA, beam energy 23 keV was produced regularly. Negative ion current of heavy impurities had a value of about 3% of the total beam current. Beam normalized emittance is about 0.3 π mm mrad and emission current density -0.1 A/cm2. A built-in cathode heater provides the operation quick start.

Diagnosing and alleviating the impact of performance pressure on mathematical problem solving.

PubMed

DeCaro, Marci S; Rotar, Kristin E; Kendra, Matthew S; Beilock, Sian L

2010-08-01

High-pressure academic testing situations can lead people to perform below their actual ability levels by co-opting working memory (WM) resources needed for the task at hand (Beilock, 2008). In the current work we examine how performance pressure impacts WM and design an intervention to alleviate pressure's negative impact. Specifically, we explore the hypothesis that high-pressure situations trigger distracting thoughts and worries that rely heavily on verbal WM. Individuals performed verbally based and spatially based mathematics problems in a low-pressure or high-pressure testing situation. Results demonstrated that performance on problems that rely heavily on verbal WM resources was less accurate under high-pressure than under low-pressure tests. Performance on spatially based problems that do not rely heavily on verbal WM was not affected by pressure. Moreover, the more people reported worrying during test performance, the worse they performed on the verbally based (but not spatially based) maths problems. Asking some individuals to focus on the problem steps by talking aloud helped to keep pressure-induced worries at bay and eliminated pressure's negative impact on performance.

Intellectual factors in false memories of patients with schizophrenia.

PubMed

Zhu, Bi; Chen, Chuansheng; Loftus, Elizabeth F; Dong, Qi; Lin, Chongde; Li, Jun

2018-07-01

The current study explored the intellectual factors in false memories of 139 patients with schizophrenia, using a recognition task and an IQ test. The full-scale IQ score of the participants ranged from 57 to 144 (M = 100, SD = 14). The full IQ score had a negative correlation with false recognition in patients with schizophrenia, and positive correlations with high-confidence true recognition and discrimination rates. Further analyses with the subtests' scores revealed that false recognition was negatively correlated with scores of performance IQ (and one of its subtests: picture arrangement), whereas true recognition was positively correlated with scores of verbal IQ (and two of its subtests: information and digit span). High-IQ patients had less false recognition (overall or high-confidence false recognition), more high-confidence true recognition, and higher discrimination abilities than those with low IQ. These findings contribute to a better understanding of the cognitive mechanism in false memory of patients with schizophrenia, and are of practical relevance to the evaluation of memory reliability in patients with different intellectual levels. Copyright © 2018 Elsevier B.V. All rights reserved.

Let it be and keep on going! Acceptance and daily occupational well-being in relation to negative work events.

PubMed

Kuba, Katharina; Scheibe, Susanne

2017-01-01

[Correction Notice: An Erratum for this article was reported in Vol 22(1) of Journal of Occupational Health Psychology (see record 2016-25216-001). In the article, there were errors in the Participants subsection in the Method section. The last three sentences should read "Job tenure ranged from less than 1 year to 32 years, with an average of 8.83 years (SD 7.80). Participants interacted with clients on average 5.44 hr a day (SD 2.41). The mean working time was 7.36 hr per day (SD 1.91)."] Negative work events can diminish daily occupational well-being, yet the degree to which they do so depends on the way in which people deal with their emotions. The aim of the current study was to examine the role of acceptance in the link between daily negative work events and occupational well-being. We hypothesized that acceptance would be associated with better daily occupational well-being, operationalized as low end-of-day negative emotions and fatigue, and high work engagement. Furthermore, we predicted that acceptance would buffer the adverse impact of negative work events on daily well-being. A microlongitudinal study across 10 work days was carried out with 92 employees of the health care sector, yielding a total of 832 daily observations. As expected, acceptance was associated with lower end-of-day negative emotions and fatigue (though there was no association with work engagement) across the 10-day period. Furthermore, acceptance moderated the effect of negative event occurrence on daily well-being: Highly accepting employees experienced less increase in negative emotions and less reduction in work engagement (though comparable end-of-day fatigue) on days with negative work events, relative to days without negative work events, than did less accepting employees. These findings highlight affective, resource-saving, and motivational benefits of acceptance for daily occupational well-being and demonstrate that acceptance is associated with enhanced resilience to daily negative work events. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Novel high-frequency energy-efficient pulsed-dc generator for capacitively coupled plasma discharge

NASA Astrophysics Data System (ADS)

Mamun, Md Abdullah Al; Furuta, Hiroshi; Hatta, Akimitsu

2018-03-01

The circuit design, assembly, and operating tests of a high-frequency and high-voltage (HV) pulsed dc generator (PDG) for capacitively coupled plasma (CCP) discharge inside a vacuum chamber are reported. For capacitive loads, it is challenging to obtain sharp rectangular pulses with fast rising and falling edges, requiring intense current for quick charging and discharging. The requirement of intense current generally limits the pulse operation frequency. In this study, we present a new type of PDG consisting of a pair of half-resonant converters and a constant current-controller circuit connected with HV solid-state power switches that can deliver almost rectangular high voltage pulses with fast rising and falling edges for CCP discharge. A prototype of the PDG is assembled to modulate from a high-voltage direct current (HVdc) input into a pulsed HVdc output, while following an input pulse signal and a set current level. The pulse rise time and fall time are less than 500 ns and 800 ns, respectively, and the minimum pulse width is 1 µs. The maximum voltage for a negative pulse is 1000 V, and the maximum repetition frequency is 500 kHz. During the pulse on time, the plasma discharge current is controlled steadily at the set value. The half-resonant converters in the PDG perform recovery of the remaining energy from the capacitive load at every termination of pulse discharge. The PDG performed with a high energy efficiency of 85% from the HVdc input to the pulsed dc output at a repetition rate of 1 kHz and with stable plasma operation in various discharge conditions. The results suggest that the developed PDG can be considered to be more efficient for plasma processing by CCP.

Novel high-frequency energy-efficient pulsed-dc generator for capacitively coupled plasma discharge.

PubMed

Mamun, Md Abdullah Al; Furuta, Hiroshi; Hatta, Akimitsu

2018-03-01

The circuit design, assembly, and operating tests of a high-frequency and high-voltage (HV) pulsed dc generator (PDG) for capacitively coupled plasma (CCP) discharge inside a vacuum chamber are reported. For capacitive loads, it is challenging to obtain sharp rectangular pulses with fast rising and falling edges, requiring intense current for quick charging and discharging. The requirement of intense current generally limits the pulse operation frequency. In this study, we present a new type of PDG consisting of a pair of half-resonant converters and a constant current-controller circuit connected with HV solid-state power switches that can deliver almost rectangular high voltage pulses with fast rising and falling edges for CCP discharge. A prototype of the PDG is assembled to modulate from a high-voltage direct current (HVdc) input into a pulsed HVdc output, while following an input pulse signal and a set current level. The pulse rise time and fall time are less than 500 ns and 800 ns, respectively, and the minimum pulse width is 1 µs. The maximum voltage for a negative pulse is 1000 V, and the maximum repetition frequency is 500 kHz. During the pulse on time, the plasma discharge current is controlled steadily at the set value. The half-resonant converters in the PDG perform recovery of the remaining energy from the capacitive load at every termination of pulse discharge. The PDG performed with a high energy efficiency of 85% from the HVdc input to the pulsed dc output at a repetition rate of 1 kHz and with stable plasma operation in various discharge conditions. The results suggest that the developed PDG can be considered to be more efficient for plasma processing by CCP.

Assessing Global Marine Biodiversity Status within a Coupled Socio-Ecological Perspective

PubMed Central

Selig, Elizabeth R.; Longo, Catherine; Halpern, Benjamin S.; Best, Benjamin D.; Hardy, Darren; Elfes, Cristiane T.; Scarborough, Courtney; Kleisner, Kristin M.; Katona, Steven K.

2013-01-01

People value the existence of a variety of marine species and habitats, many of which are negatively impacted by human activities. The Convention on Biological Diversity and other international and national policy agreements have set broad goals for reducing the rate of biodiversity loss. However, efforts to conserve biodiversity cannot be effective without comprehensive metrics both to assess progress towards meeting conservation goals and to account for measures that reduce pressures so that positive actions are encouraged. We developed an index based on a global assessment of the condition of marine biodiversity using publically available data to estimate the condition of species and habitats within 151 coastal countries. Our assessment also included data on social and ecological pressures on biodiversity as well as variables that indicate whether good governance is in place to reduce them. Thus, our index is a social as well as ecological measure of the current and likely future status of biodiversity. As part of our analyses, we set explicit reference points or targets that provide benchmarks for success and allow for comparative assessment of current conditions. Overall country-level scores ranged from 43 to 95 on a scale of 1 to 100, but countries that scored high for species did not necessarily score high for habitats. Although most current status scores were relatively high, likely future status scores for biodiversity were much lower in most countries due to negative trends for both species and habitats. We also found a strong positive relationship between the Human Development Index and resilience measures that could promote greater sustainability by reducing pressures. This relationship suggests that many developing countries lack effective governance, further jeopardizing their ability to maintain species and habitats in the future. PMID:23593188

Use of a radial self-field diode geometry for intense pulsed ion beam generation at 6 MeV on Hermes III

DOE PAGES

Renk, Timothy Jerome; Harper-Slaboszewicz, Victor Jozef; Mikkelson, Kenneth A.; ...

2014-12-15

We investigate the generation of intense pulsed focused ion beams at the 6 MeV level using an inductive voltage adder (IVA) pulsed-power generator, which employs a magnetically insulated transmission line (MITL). Such IVA machines typical run at an impedance of few tens of Ohms. Previous successful intense ion beam generation experiments have often featured an “axial” pinch-reflex ion diode (i.e., with an axial anode-cathode gap) and operated on a conventional Marx generator/water line driver with an impedance of a few Ohms and no need for an MITL. The goals of these experiments are to develop a pinch-reflex ion diode geometrymore » that has an impedance to efficiently match to an IVA, produces a reasonably high ion current fraction, captures the vacuum electron current flowing forward in the MITL, and focuses the resulting ion beam to small spot size. Furthermore, a new “radial” pinch-reflex ion diode (i.e., with a radial anode-cathode gap) is found to best demonstrate these properties. Operation in both positive and negative polarities was undertaken, although the negative polarity experiments are emphasized. Particle-in-cell (PIC) simulations are consistent with experimental results indicating that, for diode impedances less than the self-limited impedance of the MITL, almost all of the forward-going IVA vacuum electron flow current is incorporated into the diode current. PIC results also provide understanding of the diode-impedance and ion-focusing properties of the diode. Additionally, a substantial high-energy ion population is also identified propagating in the “reverse” direction, i.e., from the back side of the anode foil in the electron beam dump.« less

Use of a radial self-field diode geometry for intense pulsed ion beam generation at 6 MeV on Hermes III

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

Renk, T. J., E-mail: tjrenk@sandia.gov; Harper-Slaboszewicz, V.; Mikkelson, K. A.

2014-12-15

We investigate the generation of intense pulsed focused ion beams at the 6 MeV level using an inductive voltage adder (IVA) pulsed-power generator, which employs a magnetically insulated transmission line (MITL). Such IVA machines typical run at an impedance of few tens of Ohms. Previous successful intense ion beam generation experiments have often featured an “axial” pinch-reflex ion diode (i.e., with an axial anode-cathode gap) and operated on a conventional Marx generator/water line driver with an impedance of a few Ohms and no need for an MITL. The goals of these experiments are to develop a pinch-reflex ion diode geometry thatmore » has an impedance to efficiently match to an IVA, produces a reasonably high ion current fraction, captures the vacuum electron current flowing forward in the MITL, and focuses the resulting ion beam to small spot size. A new “radial” pinch-reflex ion diode (i.e., with a radial anode-cathode gap) is found to best demonstrate these properties. Operation in both positive and negative polarities was undertaken, although the negative polarity experiments are emphasized. Particle-in-cell (PIC) simulations are consistent with experimental results indicating that, for diode impedances less than the self-limited impedance of the MITL, almost all of the forward-going IVA vacuum electron flow current is incorporated into the diode current. PIC results also provide understanding of the diode-impedance and ion-focusing properties of the diode. In addition, a substantial high-energy ion population is also identified propagating in the “reverse” direction, i.e., from the back side of the anode foil in the electron beam dump.« less

Increased Default Mode Network Connectivity in Individuals at High Familial Risk for Depression

PubMed Central

Posner, Jonathan; Cha, Jiook; Wang, Zhishun; Talati, Ardesheer; Warner, Virginia; Gerber, Andrew; Peterson, Bradley S; Weissman, Myrna

2016-01-01

Research into the pathophysiology of major depressive disorder (MDD) has focused largely on individuals already affected by MDD. Studies have thus been limited in their ability to disentangle effects that arise as a result of MDD from precursors of the disorder. By studying individuals at high familial risk for MDD, we aimed to identify potential biomarkers indexing risk for developing MDD, a critical step toward advancing prevention and early intervention. Using resting-state functional connectivity MRI (rs-fcMRI) and diffusion MRI (tractography), we examined connectivity within the default mode network (DMN) and between the DMN and the central executive network (CEN) in 111 individuals, aged 11–60 years, at high and low familial risk for depression. Study participants were part of a three-generation longitudinal, cohort study of familial depression. Based on rs-fcMRI, individuals at high vs low familial risk for depression showed increased DMN connectivity, as well as decreased DMN-CEN-negative connectivity. These findings remained significant after excluding individuals with a current or lifetime history of depression. Diffusion MRI measures based on tractography supported the findings of decreased DMN-CEN-negative connectivity. Path analyses indicated that decreased DMN-CEN-negative connectivity mediated a relationship between familial risk and a neuropsychological measure of impulsivity. Our findings suggest that DMN and DMN-CEN connectivity differ in those at high vs low risk for depression and thus suggest potential biomarkers for identifying individuals at risk for developing MDD. PMID:26593265

Increased Default Mode Network Connectivity in Individuals at High Familial Risk for Depression.

PubMed

Posner, Jonathan; Cha, Jiook; Wang, Zhishun; Talati, Ardesheer; Warner, Virginia; Gerber, Andrew; Peterson, Bradley S; Weissman, Myrna

2016-06-01

Research into the pathophysiology of major depressive disorder (MDD) has focused largely on individuals already affected by MDD. Studies have thus been limited in their ability to disentangle effects that arise as a result of MDD from precursors of the disorder. By studying individuals at high familial risk for MDD, we aimed to identify potential biomarkers indexing risk for developing MDD, a critical step toward advancing prevention and early intervention. Using resting-state functional connectivity MRI (rs-fcMRI) and diffusion MRI (tractography), we examined connectivity within the default mode network (DMN) and between the DMN and the central executive network (CEN) in 111 individuals, aged 11-60 years, at high and low familial risk for depression. Study participants were part of a three-generation longitudinal, cohort study of familial depression. Based on rs-fcMRI, individuals at high vs low familial risk for depression showed increased DMN connectivity, as well as decreased DMN-CEN-negative connectivity. These findings remained significant after excluding individuals with a current or lifetime history of depression. Diffusion MRI measures based on tractography supported the findings of decreased DMN-CEN-negative connectivity. Path analyses indicated that decreased DMN-CEN-negative connectivity mediated a relationship between familial risk and a neuropsychological measure of impulsivity. Our findings suggest that DMN and DMN-CEN connectivity differ in those at high vs low risk for depression and thus suggest potential biomarkers for identifying individuals at risk for developing MDD.

Current management of prosthetic joint infections in adults: results of an Emerging Infections Network survey

PubMed Central

Marschall, Jonas; Lane, Michael A.; Beekmann, Susan E.; Polgreen, Philip; Babcock, Hilary M.

2013-01-01

There is a dearth of guidance on the management of prosthetic joint infections (PJIs), in particular because of the lack of high-quality evidence for optimal antibiotics. Thus, we designed a nine-question survey of current practices and preferences among members of the Emerging Infections Network, a CDC-sponsored network of infectious diseases physicians, which was distributed in May 2012. In total, 556 (47.2%) of 1178 network members responded. As first-line antibiotic choice for MSSA PJI, 59% of responders indicated oxacillin/nafcillin, 33% cefazolin and 7% ceftriaxone; the commonest alternative was cefazolin (46%). For MRSA PJI, 90% preferred vancomycin, 7% daptomycin and 0.8% ceftaroline; the commonest alternative was daptomycin (65%). Antibiotic selection for coagulase-negative staphylococci varied depending on meticillin susceptibility. For staphylococcal PJIs with retained hardware, most providers would add rifampicin. Propionibacterium is usually treated with vancomycin (40%), penicillin (23%) or ceftriaxone (17%). Most responders thought 10–19% of all PJIs were culture-negative. Culture-negative PJIs of the lower extremities are usually treated with a vancomycin/fluoroquinolone combination, and culture-negative shoulder PJIs with vancomycin/ceftriaxone. The most cited criteria for selecting antibiotics were ease of administration and the safety profile. A treatment duration of 6–8 weeks is preferred (by 77% of responders) and is mostly guided by clinical response and inflammatory markers. Ninety-nine percent of responders recommend oral antibiotic suppression (for varying durations) in patients with retained hardware. In conclusion, there is considerable variation in treatment of PJIs both with identified pathogens and those with negative cultures. Future studies should aim to identify optimum treatment strategies. PMID:23312602

Does counselling improve uptake of long-term and permanent contraceptive methods in a high HIV-prevalence setting?

PubMed

Siveregi, Amon; Dudley, Lilian; Makumucha, Courage; Dlamini, Phatisizwe; Moyo, Sihle; Bhembe, Sibongiseni

2015-11-06

Studies have shown a reduced uptake of contraceptive methods in HIV-positive women of childbearing age, mainly because of unmet needs that may be a result of poor promotion of available methods of contraception, especially long-term and permanent methods (LTPM). To compare the uptake of contraceptive methods, and particularly LTPM, by HIV-positive and HIV negative post-partum mothers, and to assess the effects of counselling on contraceptive choices. Three government district hospitals in Swaziland. Interviews were conducted using a structured questionnaire, before and after counselling HIV negativeand HIV-positive post-partum women in LTPM use, unintended pregnancy rates, future fertility and reasons for contraceptive choices. A total of 711 women, of whom half were HIV-positive, participated in the study. Most (72.3% HIV-negative and 84% HIV-positive) were on modern methods of contraception, with the majority using 2-monthly and 3-monthly injectables. Intended use of any contraceptive increased to 99% after counselling. LTPM use was 7.0% in HIV-negative mothers and 15.3% in HIV-positive mothers before counselling, compared with 41.3% and 42.4% in HIV-negative and HIV-positive mothers, respectively, after counselling. Pregnancy intentions and counselling on future fertility were significantly associated with current use of contraception, whilst current LTPM use and level of education were significantly associated with LTPM post-counselling. Counselling on all methods including LTPM reduced unmet needs in contraception in HIV positive and HIV-negative mothers and could improve contraceptive uptake and reduce unintended pregnancies. Health workers do not always remember to include LTPM when they counsel clients, which could result in a low uptake of these methods. Further experimental studies should be conducted to validate these results.

The impact of stress on depressive symptoms is moderated by social support in Chinese adolescents with subthreshold depression: a multi-wave longitudinal study.

PubMed

Yang, Juan; Yao, Shuqiao; Zhu, Xiongzhao; Zhang, Chenchen; Ling, Yu; Abela, John R Z; Esseling, Petra G; McWhinnie, Chad

2010-12-01

Most studies have shown that negative life events and social support are important factors in the development and outcome of depression. It is unknown if these factors are important in adolescents with subthreshold depression. Thus, the current study examined whether high levels of social support from peers buffer adolescents exhibiting subthreshold depressive symptoms against experiencing further increases in such symptoms following the occurrence of negative events. Participants included 143 adolescents (aged 14 to 18; M=16.07, SD=.66) in Hunan Province China who were selected because they were exhibiting subthreshold depressive symptoms at the time of initial assessment. During an initial assessment, participants completed measures assessing social support from peers and depressive symptoms. Participants subsequently completed measures assessing depressive symptoms and the occurrence of negative events once every three months for the subsequent fifteen months. The prevalence of lifetime subthreshold depression in Hunan was 22.9% (n=143). The results of hierarchical linear modeling analyses indicated that lower levels of social support from peers was associated with greater increases in depressive symptoms following the occurrence of negative events. The results suggested that the association between the occurrence of negative events and increased depressive symptoms is moderated by social support from peers in adolescents with subthreshold depression in mainland China, in line with the buffering hypothesis. The adolescent sample used in the current study was from Hunan, China, which could limit the generalizability of our results to other populations. In addition, given that it is possible that cultural context shapes symptom manifestation, future research should assess a broader array of symptom outcomes. Copyright © 2010 Elsevier B.V. All rights reserved.

Negation in Context: A Functional Approach to Suppression

ERIC Educational Resources Information Center

Giora, Rachel; Fein, Ofer; Aschkenazi, Keren; Alkabets-Zlozover, Inbar

2007-01-01

Three experiments show that, contrary to the current view, comprehenders do not unconditionally deactivate information marked by negation. Instead, they discard negated information when it is functionally motivated. In Experiment 1, comprehenders discarded negated concepts when cued by a topic shift to dampen recently processed information.…

Math anxiety in Thai early adolescents: a cognitive-behavioral perspective.

PubMed

Wangsiriwech, Tawatchai; Pisitsungkagarn, Kullaya; Jarukasemthawee, Somboon

2017-08-29

With its high prevalence and debilitating impact on students, math anxiety is well studied within the educational context. However, the problem has yet to be examined from the psychological perspective, which is necessary in order to produce a more comprehensive perspective and to pave the way for therapeutic intervention. The current study, therefore, was conducted to identify cognitive and behavioral factors relevant to the occurrence and maintenance of math anxiety. Data were collected from 300 grade 9 students (150 females and 150 males) from public and private schools in Bangkok, Thailand. Participants responded to the measures of math anxiety, negative math beliefs, negative math appraisals and math avoidance. Structural equation modeling was conducted. Model fit indices obtained consistently suggested the good fitness of the model to the data [e.g. χ2/df = 0.42, root mean square error of approximation (RMSEA) = 0.00]. Negative math beliefs, negative math appraisals and math avoidance had a significant direct effect on math anxiety. Additionally, the indirect effect of negative math appraisal was observed between negative math beliefs and math anxiety. In summary, the proposed model accounted for 84.5% of the variance in the anxiety. The findings are discussed with particular focus on implications for therapeutic intervention for math anxiety.

Bim-mediated apoptosis is not necessary for thymic negative selection to ubiquitous self-antigens.

PubMed

Hu, Qian; Sader, Alyssa; Parkman, Julia C; Baldwin, Troy A

2009-12-15

T cell education in the thymus is critical for establishing a functional, yet self-tolerant, T cell repertoire. Negative selection is a key process in enforcing self-tolerance. There are many questions that surround the mechanism of negative selection, but it is currently held that apoptosis initiated by Bim and/or Nur77 is critical for negative selection. Recent studies, however, have questioned the necessity of Bim in maintaining both central and peripheral T cell tolerance. To reconcile these apparently contradictory findings, we examined the role of Bim in negative selection in the well-characterized, physiological HY(cd4) mouse model. We found that while Bim expression was required for CD4(+)CD8(+) double-positive thymocyte apoptosis, it was not required for negative selection. Furthermore, Bim deficiency did not alter the frequency or affinity of male reactive cells that escape negative selection in an oligoclonal repertoire. Collectively, these studies indicate that negative selection occurs efficiently in the absence of apoptosis and suggest that the current paradigm of negative selection requiring apoptosis be revisited.

Negative emotionality, depressive symptoms and cortisol diurnal rhythms: analysis of a community sample of middle-aged males.

PubMed

Doane, Leah D; Franz, Carol E; Prom-Wormley, Elizabeth; Eaves, Lindon J; Mendoza, Sally P; Hellhammer, Dirk H; Lupien, Sonia; Xian, Hong; Lyons, Michael J; Kremen, William; Jacobson, Kristen C

2011-07-01

Prior research suggests that individuals with particular personality traits, like negative emotionality, are at greater risk for adverse health outcomes. Despite bivariate associations between negative emotionality, depressive symptoms and the hypothalamic pituitary adrenal axis (HPA axis), few studies have sought to understand the biological pathways through which negative emotionality, depressive symptomatology and cortisol-one of the primary hormonal products of the HPA axis--are associated. The present study explored whether negative emotionality influenced cortisol dysregulation through current depressive symptomatology and whether negative emotionality served as a moderator of the relationship between depressive symptoms and cortisol. In the community-based Vietnam Era Twin Study of Aging, 783 male twins completed two days of cortisol saliva sampling in their natural environments. Three measures of cortisol were analyzed: waking levels, the cortisol awakening response, and the peak to bed slope. Depressive symptoms significantly mediated the associations between negative emotionality and the peak to bed slope. A 2-way interaction between depressive symptoms and negative emotionality was significant for the peak to bed slope and for waking levels of cortisol. Exploration of the interactions illustrated that depressive symptoms only affected cortisol slopes at average or high levels of negative emotionality and only affected waking levels at low levels of negative emotionality. Negative emotionality and depressive symptoms were not related to the cortisol awakening response. This is the first study to find indirect associations between negative emotionality and peak to bed cortisol slopes through depressive symptoms. These findings illustrate the complex interplay between personality characteristics, depressive symptoms and different indices of the cortisol diurnal rhythm. Copyright © 2011 Elsevier Inc. All rights reserved.

Video, LMA and ULF observations of a negative gigantic jet in North Texas

NASA Astrophysics Data System (ADS)

Bruning, E. C.; Cummer, S.; Palivec, K.; Lyons, W. A.; Chmielewski, V.; MacGorman, D. R.

2017-12-01

On 8 September 2016 at 0125:38 UTC video of a negative gigantic jet was captured from Hawley, TX. VHF Lightning Mapping Arrays in West Texas and Oklahoma also observed the parent flash (duration of about 1 s) and, for the first time, mapped dozens of points along ascending negative leaders, lasting about 50 ms, which extended well above cloud top to about 35 km MSL altitude. A few well-located VHF sources were also detected near 50 km. Together, the video and VHF observations provide additional confirmation of the altitude at which the leader-to-streamer transition takes place in gigantic jet discharges. ULF magnetic field data from the Duke iCMC network show a current excursion associated with the onset of the upward movement of negative charge and leaders in the VHF. As the gigantic jet reached its full height, current spiked to 80 kA, followed by several hundred milliseconds of continuing current of 10-20 kA. Total charge moment change was about 6000 C km. The storm complex produced predominantly negative large charge moment change events, which is characteristic of storms that produce negative gigantic jets.

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

Zhang, A. L.; Chen, J. E.; State Key Laboratory of Nuclear Physics and Technology, Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871

Negative hydrogen ion beam can be compensated by the trapping of ions into the beam potential. When the beam propagates through a neutral gas, these ions arise due to gas ionization by the beam ions. However, the high neutral gas pressure may cause serious negative hydrogen ion beam loss, while low neutral gas pressure may lead to ion-ion instability and decompensation. To better understand the space charge compensation processes within a negative hydrogen beam, experimental study and numerical simulation were carried out at Peking University (PKU). The simulation code for negative hydrogen ion beam is improved from a 2D particle-in-cell-Montemore » Carlo collision code which has been successfully applied to H{sup +} beam compensated with Ar gas. Impacts among ions, electrons, and neutral gases in negative hydrogen beam compensation processes are carefully treated. The results of the beam simulations were compared with current and emittance measurements of an H{sup −} beam from a 2.45 GHz microwave driven H{sup −} ion source in PKU. Compensation gas was injected directly into the beam transport region to modify the space charge compensation degree. The experimental results were in good agreement with the simulation results.« less

Cell design for lithium alloy/metal sulfide battery

DOEpatents

Kaun, Thomas D.

1985-01-01

The disclosed lithium alloy/iron sulfide cell design provides loop-like positive and negative sheet metal current collectors electrically insulated from one another by separator means, the positive collector being located outwardly of the negative collector. The collectors are initially secured within an open-ended cell housing, which allows for collector pretesting for electrical shorts prior to adding any electrode materials and/or electrolyte to the cell. Separate chambers are defined outwardly of the positive collector and inwardly of the negative collector open respectively in opposite directions toward the open ends of the cell housing; and positive and negative electrode materials can be extruded into these respective chambers via the opposite open housing ends. The chambers and cell housing ends can then be sealed closed. A cross wall structurally reinforces the cell housing and also thereby defines two cavities, and paired positive and negative collectors are disposed in each cavity and electrically connected in parallel. The cell design provides for a high specific energy output and improved operating life in that any charge-discharge cycle swelling of the positive electrode material will be inwardly against only the positive collector to minimize shorts caused by the collectors shifting relative to one another.

Improved cell design for lithium alloy/metal sulfide battery

DOEpatents

Kaun, T.D.

1984-03-30

The disclosed lithium alloy/iron sulfide cell design provides loop-like positive and negative sheet metal current collectors electrically insulated from one another by separator means, the positive collector being located outwardly of the negative collector. The collectors are initially secured within an open-ended cell housing, which allows for collector pretesting for electrical shorts prior to adding any electrode materials and/or electrolyte to the cell. Separate chambers are defined outwardly of the positive collector and inwardly of the negative collector open respectively in opposite directions toward the open ends of the cell housing; and positive and negative electrode materials can be extruded into these respective chambers via the opposite open housing ends. The chambers and cell housing ends can then be sealed closed. A cross wall structurally reinforces the cell housing and also thereby defines two cavities, and paired positive and negative collectors are disposed in each cavity and electrically connected in parallel. The cell design provides for a high specific energy output and improved operating life in that any charge-discharge cycle swelling of the positive electrode material will be inwardly against only the positive collector to minimize shorts caused by the collectors shifting relative to one another.

Large-scale optimization-based non-negative computational framework for diffusion equations: Parallel implementation and performance studies

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

Chang, Justin; Karra, Satish; Nakshatrala, Kalyana B.

It is well-known that the standard Galerkin formulation, which is often the formulation of choice under the finite element method for solving self-adjoint diffusion equations, does not meet maximum principles and the non-negative constraint for anisotropic diffusion equations. Recently, optimization-based methodologies that satisfy maximum principles and the non-negative constraint for steady-state and transient diffusion-type equations have been proposed. To date, these methodologies have been tested only on small-scale academic problems. The purpose of this paper is to systematically study the performance of the non-negative methodology in the context of high performance computing (HPC). PETSc and TAO libraries are, respectively, usedmore » for the parallel environment and optimization solvers. For large-scale problems, it is important for computational scientists to understand the computational performance of current algorithms available in these scientific libraries. The numerical experiments are conducted on the state-of-the-art HPC systems, and a single-core performance model is used to better characterize the efficiency of the solvers. Furthermore, our studies indicate that the proposed non-negative computational framework for diffusion-type equations exhibits excellent strong scaling for real-world large-scale problems.« less

Analysis of the Negative-SET Behaviors in Cu/ZrO2/Pt Devices

NASA Astrophysics Data System (ADS)

Liu, Sen; Zhao, Xiaolong; Li, Qingjiang; Li, Nan; Wang, Wei; Liu, Qi; Xu, Hui

2016-12-01

Metal oxide-based electrochemical metallization memory (ECM) shows promising performance for next generation non-volatile memory. The negative-SET behavior has been observed in various oxide-based ECM devices. But the underlying mechanism of this behavior remains unaddressed and the role of the metal cation and oxygen vacancy in this behavior is unclear. In this work, we have observed two kinds of negative-SET (labeled as N-SET1 and N-SET2) behaviors in our Cu/ZrO2/Pt devices. Both the two behaviors can result in hard breakdown due to the high compliance current in reset process. The I-V characteristic shows that the two negative-SET behaviors have an obvious difference in operation voltage. Using four-probe resistance measurement method, the resistance-temperature characteristics of the ON-state after various negative-SET behaviors have been studied. The temperature dependence results demonstrate that the N-SET1 behavior is dominated by Cu conductive filament (CF) reformation caused by the Cu CF overgrowth phenomenon while the N-SET2 is related to the formation of oxygen vacancy CF. This work may provide a comprehensive understanding of the switching mechanism in oxide-based ECM devices.

Large-scale optimization-based non-negative computational framework for diffusion equations: Parallel implementation and performance studies

DOE PAGES

Chang, Justin; Karra, Satish; Nakshatrala, Kalyana B.

2016-07-26

It is well-known that the standard Galerkin formulation, which is often the formulation of choice under the finite element method for solving self-adjoint diffusion equations, does not meet maximum principles and the non-negative constraint for anisotropic diffusion equations. Recently, optimization-based methodologies that satisfy maximum principles and the non-negative constraint for steady-state and transient diffusion-type equations have been proposed. To date, these methodologies have been tested only on small-scale academic problems. The purpose of this paper is to systematically study the performance of the non-negative methodology in the context of high performance computing (HPC). PETSc and TAO libraries are, respectively, usedmore » for the parallel environment and optimization solvers. For large-scale problems, it is important for computational scientists to understand the computational performance of current algorithms available in these scientific libraries. The numerical experiments are conducted on the state-of-the-art HPC systems, and a single-core performance model is used to better characterize the efficiency of the solvers. Furthermore, our studies indicate that the proposed non-negative computational framework for diffusion-type equations exhibits excellent strong scaling for real-world large-scale problems.« less

Interactive and Indirect Effects of Anxiety and Negative Urgency on Alcohol-Related Problems

PubMed Central

Menary, Kyle R.; Corbin, William R.; Leeman, Robert F.; Fucito, Lisa M.; Toll, Benjamin A.; DeMartini, Kelly; O’Malley, Stephanie S.

2015-01-01

Background Although drinking for tension reduction has long been posited as a risk factor for alcohol-related problems, studies investigating anxiety in relation to risk for alcohol problems have returned inconsistent results, leading researchers to search for potential moderators. Negative urgency (the tendency to become behaviorally dysregulated when experiencing negative affect) is a potential moderator of theoretical interest because it may increase risk for alcohol problems among those high in negative affect. The present study tested a cross-sectional mediated moderation hypothesis whereby an interactive effect of anxiety and negative urgency on alcohol problems is mediated through coping-related drinking motives. Method The study utilized baseline data from a hazardously drinking sample of young adults (N = 193) evaluated for participation in a randomized controlled trial of naltrexone and motivational interviewing for drinking reduction. Results The direct effect of anxiety on physiological dependence symptoms was moderated by negative urgency such that the positive association between anxiety and physiological dependence symptoms became stronger as negative urgency increased. Indirect effects of anxiety and negative urgency on alcohol problems (operating through coping motives) were also observed. Conclusions Although results of the current cross-sectional study require replication using longitudinal data, the findings suggest that the simultaneous presence of anxiety and negative urgency may be an important indicator of risk for AUDs via both direct interactive effects and indirect additive effects operating through coping motives. These findings have potentially important implications for prevention/intervention efforts for individuals who become disinhibited in the context of negative emotional states. PMID:26031346

Clinical risk stratification model for advanced colorectal neoplasia in persons with negative fecal immunochemical test results.

PubMed

Jung, Yoon Suk; Park, Chan Hyuk; Kim, Nam Hee; Park, Jung Ho; Park, Dong Il; Sohn, Chong Il

2018-01-01

The fecal immunochemical test (FIT) has low sensitivity for detecting advanced colorectal neoplasia (ACRN); thus, a considerable portion of FIT-negative persons may have ACRN. We aimed to develop a risk-scoring model for predicting ACRN in FIT-negative persons. We reviewed the records of participants aged ≥40 years who underwent a colonoscopy and FIT during a health check-up. We developed a risk-scoring model for predicting ACRN in FIT-negative persons. Of 11,873 FIT-negative participants, 255 (2.1%) had ACRN. On the basis of the multivariable logistic regression model, point scores were assigned as follows among FIT-negative persons: age (per year from 40 years old), 1 point; current smoker, 10 points; overweight, 5 points; obese, 7 points; hypertension, 6 points; old cerebrovascular attack (CVA), 15 points. Although the proportion of ACRN in FIT-negative persons increased as risk scores increased (from 0.6% in the group with 0-4 points to 8.1% in the group with 35-39 points), it was significantly lower than that in FIT-positive persons (14.9%). However, there was no statistical difference between the proportion of ACRN in FIT-negative persons with ≥40 points and in FIT-positive persons (10.5% vs. 14.9%, P = 0.321). FIT-negative persons may need to undergo screening colonoscopy if they clinically have a high risk of ACRN. The scoring model based on age, smoking habits, overweight or obesity, hypertension, and old CVA may be useful in selecting and prioritizing FIT-negative persons for screening colonoscopy.

Trauma and Poor Mental Health in Relation to Economic Status: The Case of Cambodia 35 Years Later

PubMed Central

Jarl, Johan; Cantor-Graae, Elizabeth; Chak, Thida; Sunbaunat, Ka; Larsson, Charlotte A

2015-01-01

Background Cambodia is one of the poorest countries in south-east Asia and is still emerging from the events of the Khmer Rouge reign. It has been suggested that the atrocities experienced by the Cambodian population can explain why Cambodia continues to lag behind its neighbours in economic outcomes. The purpose of this study is to investigate whether there is an association between exposure to past trauma and/or current poor mental health and current economic status in Cambodia. Method A newly conducted survey performed in two regions (north-west and south-east Cambodia) collected information on trauma exposure, psychiatric symptoms, self-rated health outcomes and socio-economic information for 3200 persons aged 18–60. Economic outcomes were measured as household debt and poverty status and whether the respondent was economically inactive. All models were analysed using logistic regression. Results No association was found between high exposure to conflict-related or civilian trauma and any economic outcomes save for a negative association between civilian trauma and poverty in the south-east. Current post-traumatic stress was related solely to poverty status. All other measures of current mental health status, however, were found to be strongly negatively associated with all measures of economic status. Thus, mental health interventions could potentially be utilised in poverty reduction strategies, but greater efficacy is likely to be achieved by targeting current mental health status rather than previous trauma exposure. PMID:26301591

Encoding negative events under stress: high subjective arousal is related to accurate emotional memory despite misinformation exposure.

PubMed

Hoscheidt, Siobhan M; LaBar, Kevin S; Ryan, Lee; Jacobs, W Jake; Nadel, Lynn

2014-07-01

Stress at encoding affects memory processes, typically enhancing, or preserving, memory for emotional information. These effects have interesting implications for eyewitness accounts, which in real-world contexts typically involve encoding an aversive event under stressful conditions followed by potential exposure to misinformation. The present study investigated memory for a negative event encoded under stress and subsequent misinformation endorsement. Healthy young adults participated in a between-groups design with three experimental sessions conducted 48 h apart. Session one consisted of a psychosocial stress induction (or control task) followed by incidental encoding of a negative slideshow. During session two, participants were asked questions about the slideshow, during which a random subgroup was exposed to misinformation. Memory for the slideshow was tested during the third session. Assessment of memory accuracy across stress and no-stress groups revealed that stress induced just prior to encoding led to significantly better memory for the slideshow overall. The classic misinformation effect was also observed - participants exposed to misinformation were significantly more likely to endorse false information during memory testing. In the stress group, however, memory accuracy and misinformation effects were moderated by arousal experienced during encoding of the negative event. Misinformed-stress group participants who reported that the negative slideshow elicited high arousal during encoding were less likely to endorse misinformation for the most aversive phase of the story. Furthermore, these individuals showed better memory for components of the aversive slideshow phase that had been directly misinformed. Results from the current study provide evidence that stress and high subjective arousal elicited by a negative event act concomitantly during encoding to enhance emotional memory such that the most aversive aspects of the event are well remembered and subsequently more resistant to misinformation effects. Copyright © 2013 The Authors. Published by Elsevier Inc. All rights reserved.

The Toronto Lesbian Family Study.

PubMed

Dundas, S; Kaufman, M

2000-01-01

Twenty-seven lesbian mothers completed standardized tools chosen to assess current functioning, followed by a video-taped interview. Verbal children were also interviewed. Questions involved perceptions of the mothers' and children's experiences of being homosexual or being raised by homosexual parents, knowledge and fantasies about the donor/father, feelings regarding the role of fathers, parents' experiences of being fathered, legal issues, and development. All mothers were strongly lesbian identified and most were completely "out." All but one mother planned to or had told their children. All mothers planned to reveal donor information at an appropriate age. Many, especially parents of boys, had concerns about lack of a male role model, but none felt this would negatively affect the child's development. Mothers were open to having their child ask questions and even seek out the donor when older. Thirty-one percent of mothers reported a positive relationship with their own father, 42% a father who was present but unavailable or punitive and 27% a completely absent father for large parts of their childhood. Couples divided parenting work based on individual strengths and interests, work schedules and demands. Only two of the couples felt that one of them played a role typical of a father. An aggregate score was compiled for each mother based on the number of negative outcomes in the standardized tools. The mean number of negative outcomes for the mothers was 3.15 (SD = 1.85). Of the six women with 5 or more negative outcomes on the scales, three were single parents and one had lost her partner when her child was two months old. On the CESD, three mothers showed depression levels that were high. The Internal External scale showed 42% of mothers to have an external locus of control. Three mothers scored negatively on the Family Assessment Device. Ninety-two percent of women showed moderate to high self-esteem on the Rosenberg Self-Esteem scale, and the Parenting Stress Index found only 4 women showing enough stress to warrant follow-up. Mothers who reported very negative early experiences of coming out were more likely to report current depressive symptoms (p = .03). All but one child living in two-mother homes identified both mothers as part of their family. Our initial impression is that these are primarily strong families with a variety of parenting skills, stressors and philosophies.

Not self-focused attention but negative beliefs affect poor social performance in social anxiety: an investigation of pathways in the social anxiety-social rejection relationship.

PubMed

Voncken, Marisol J; Dijk, Corine; de Jong, Peter J; Roelofs, Jeffrey

2010-10-01

Patients with social anxiety disorder (SAD) not only fear negative evaluation but are indeed less likeable than people without SAD. Previous research shows social performance to mediate this social anxiety-social rejection relationship. This study studied two pathways hypothesized to lead to poor social performance in social anxiety: increased self-focused attention and negative beliefs. State social anxiety was experimentally manipulated in high and low-blushing-fearful individuals by letting half of the participants believe that they blushed intensely during a 5 min getting-acquainted interaction with two confederates. Participants rated their state social anxiety, self-focused attention, and level of negative beliefs. Two confederates and two video-observers rated subsequently likeability (i.e., social rejection) and social performance of the participants. In both groups, the social anxiety-social rejection relationship was present. Although state social anxiety was related to heightened self-focused attention and negative beliefs, only negative beliefs were associated with relatively poor social performance. In contrast to current SAD models, self-focused attention did not play a key-role in poor social performance but seemed to function as a by-product of state social anxiety. Beliefs of being negatively evaluated seem to elicit changes in behavioral repertoire resulting in a poor social performance and subsequent rejection. Copyright 2010 Elsevier Ltd. All rights reserved.

Transmission Electron Microscopy as a Tool to Image Bio-Inorganic Nanohybrids: The Case of Phage-Gold Nanocomposites

PubMed Central

Cao, Binrui; Xu, Hong; Mao, Chuanbin

2011-01-01

In recent years, bio-inorganic nanohybrids composed of biological macromolecules and functional inorganic nanomaterials have revealed many unique properties that show promise for the future. Transmission electron microscopy (TEM) is a popular and relatively simple tool that can offer a direct visualization of the nanomaterials with high resolutions. When TEM is applied to visualize bio-inorganic nanohybrids, a treatment of negative staining is necessary due to the presence of biological molecules in the nanohybrids except for those with densely packed inorganic materials. However, the conventional negative-staining procedure for regular biological samples cannot be directly applied to such bio-inorganic nanohybrids. To image a specific bio-inorganic nanohybrid, negative-staining factors such as negative stain type, working pH, staining time, and drying method, should be identified. Currently, no detailed studies have been done to investigate how to adjust negative-staining factors based on specific bio-inorganic nanohybrids. In this study, bacteriophage-gold nanoparticle hybrids were chosen as a model to systematically study the effects of each factor on the negative staining of the nanohybrids. The best staining conditions for gold nanoparticle-phage nanohybrids were obtained and the effects of each factor on the negative staining of general nanohybrids were discussed. This work indicates that with proper staining it is possible to use TEM to directly visualize both biological and inorganic components without introducing any artifact. PMID:21678527

Integrating eating disorder-specific risk factors into the acquired preparedness model of dysregulated eating: A moderated mediation analysis.

PubMed

Racine, Sarah E; Martin, Shelby J

2017-01-01

Tests of the acquired preparedness model demonstrate that the personality trait of negative urgency (i.e., the tendency to act impulsively when distressed) predicts the expectation that eating alleviates negative affect, and this eating expectancy subsequently predicts dysregulated eating. Although recent data indicate that eating disorder-specific risk factors (i.e., appearance pressures, thin-ideal internalization, body dissatisfaction, dietary restraint) strengthen negative urgency-dysregulated eating associations, it is unclear whether these risk factors impact associations directly or indirectly (i.e., through eating expectancies). The current study used latent moderated structural equation modeling to test moderated mediation hypotheses in a sample of 313 female college students. Eating expectancies mediated the association between negative urgency and dysregulated eating, and the indirect effect of negative urgency on dysregulated eating through eating expectancies was conditional on level of each eating disorder risk factor. Appearance pressures, thin-ideal internalization, body dissatisfaction, and dietary restraint significantly moderated the association between eating expectancies and dysregulated eating, while only dietary restraint moderated the direct effect of negative urgency on dysregulated eating. Findings suggest that the development of high-risk eating expectancies among individuals with negative urgency, combined with sociocultural pressures for thinness and their consequences, is associated with the greatest risk for dysregulated eating. Copyright © 2016 Elsevier Ltd. All rights reserved.

Controlling Electron Backstreaming Phenomena Through the Use of a Transverse Magnetic Field

NASA Technical Reports Server (NTRS)

Foster, John E.; Patterson, Michael J.

2002-01-01

DEEP-SPACE mission propulsion requirements can be satisfied by the use of high specific impulse systems such as ion thrusters. For such missions. however. the ion thruster will be required to provide thrust for long periods of time. To meet the long operation time and high-propellant throughput requirements, thruster lifetime must be increased. In general, potential ion thruster failure mechanisms associated with long-duration thrusting can be grouped into four areas: (1) ion optics failure; (2) discharge cathode failure; (3) neutralizer failure; and (4) electron backstreaming caused by accelerator grid aperture enlargement brought on by accelerator grid erosion. The work presented here focuses on electron backstreaming. which occurs when the potential at the center of an accelerator grid aperture is insufficient to prevent the backflow of electrons into the ion thruster. The likelihood of this occurring depends on ion source operation time. plasma density, and grid voltages, as accelerator grid apertures enlarge as a result of erosion. Electrons that enter the gap between the high-voltage screen and accelerator grids are accelerated to the energies approximately equal to the beam voltage. This energetic electron beam (typically higher than 1 kV) can damage not only the ion source discharge cathode assembly. but also any of the discharge surfaces upstream of the ion acceleration optics that the electrons happen to impact. Indeed. past backstreaming studies have shown that near the backstreaming limit, which corresponds to the absolute value of the accelerator grid voltage below which electrons can backflow into the thruster, there is a rather sharp rise in temperature at structures such as the cathode keeper electrode. In this respect operation at accelerator grid voltages near the backstreaming limit is avoided. Generally speaking, electron backstreaming is prevented by operating the accelerator grid at a sufficiently negative voltage to ensure a sufficiently negative aperture center potential. This approach can provide the necessary margin assuming an expected aperture enlargement. Operation at very negative accelerator grid voltages, however, enhances ion charge-exchange and direct impingement erosion of the accelerator grid. The focus of the work presented here is the mitigation of electron backstreaming by the use of a magnetic field. The presence of a magnetic field oriented perpendicular to the thruster axis can significantly decrease the magnitude of the backflowing electron current by significantly reducing the electron diffusion coefficient. Negative ion sources utilize this principle to reduce the fraction of electrons in the negative ion beam. The focus of these efforts has been on the attenuation of electron current diffusing from the discharge plasma into the negative ion extraction optics by placing the transverse magnetic field upstream of the extraction electrodes. In contrast. in the case of positive ion sources such as ion thrusters, the approach taken in the work presented here is to apply the transverse field downstream of the ion extraction system so as to prevent electrons from flowing back into the source. It was found in the work presented here that the magnetic field also reduces the absolute value of the electron backstreaming limit voltage. In this respect. the applied transverse magnetic field provides two mechanisms for electron backstreaming mitigation: (1) electron current attenuation and (2) backstreaming limit voltage shift. Such a shift to less negative voltages can lead to reduced accelerator grid erosion rates.

Theory of step on leading edge of negative corona current pulse

NASA Astrophysics Data System (ADS)

Gupta, Deepak K.; Mahajan, Sangeeta; John, P. I.

2000-03-01

Theoretical models taking into account different feedback source terms (e.g., ion-impact electron emission, photo-electron emission, field emission, etc) have been proposed for the existence and explanation of the shape of negative corona current pulse, including the step on the leading edge. In the present work, a negative corona current pulse with the step on the leading edge is obtained in the presence of ion-impact electron emission feedback source only. The step on the leading edge is explained in terms of the plasma formation process and enhancement of the feedback source. Ionization wave-like movement toward the cathode is observed after the step. The conditions for the existence of current pulse, with and without the step on the leading edge, are also described. A qualitative comparison with earlier theoretical and experimental work is also included.

Low bias negative differential conductance and reversal of current in coupled quantum dots in different topological configurations

NASA Astrophysics Data System (ADS)

Devi, Sushila; Brogi, B. B.; Ahluwalia, P. K.; Chand, S.

2018-06-01

Electronic transport through asymmetric parallel coupled quantum dot system hybridized between normal leads has been investigated theoretically in the Coulomb blockade regime by using Non-Equilibrium Green Function formalism. A new decoupling scheme proposed by Rabani and his co-workers has been adopted to close the chain of higher order Green's functions appearing in the equations of motion. For resonant tunneling case; the calculations of current and differential conductance have been presented during transition of coupled quantum dot system from series to symmetric parallel configuration. It has been found that during this transition, increase in current and differential conductance of the system occurs. Furthermore, clear signatures of negative differential conductance and negative current appear in series case, both of which disappear when topology of system is tuned to asymmetric parallel configuration.

High current density 2D/3D MoS2/GaN Esaki tunnel diodes

NASA Astrophysics Data System (ADS)

Krishnamoorthy, Sriram; Lee, Edwin W.; Lee, Choong Hee; Zhang, Yuewei; McCulloch, William D.; Johnson, Jared M.; Hwang, Jinwoo; Wu, Yiying; Rajan, Siddharth

2016-10-01

The integration of two-dimensional materials such as transition metal dichalcogenides with bulk semiconductors offer interesting opportunities for 2D/3D heterojunction-based device structures without any constraints of lattice matching. By exploiting the favorable band alignment at the GaN/MoS2 heterojunction, an Esaki interband tunnel diode is demonstrated by transferring large area Nb-doped, p-type MoS2 onto heavily n-doped GaN. A peak current density of 446 A/cm2 with repeatable room temperature negative differential resistance, peak to valley current ratio of 1.2, and minimal hysteresis was measured in the MoS2/GaN non-epitaxial tunnel diode. A high current density of 1 kA/cm2 was measured in the Zener mode (reverse bias) at -1 V bias. The GaN/MoS2 tunnel junction was also modeled by treating MoS2 as a bulk semiconductor, and the electrostatics at the 2D/3D interface was found to be crucial in explaining the experimentally observed device characteristics.

Electroluminescence and other diagnostic techniques for the study of hot-electron effects in compound semiconductor devices

NASA Astrophysics Data System (ADS)

Zanoni, Enrico; Meneghesso, Gaudenzio; Menozzi, Roberto

2000-03-01

Hot electron in III-V FETs can be indirectly monitored by measuring the current coming out from the gate when the device is biased at high electric fields. This negative current is due to the collection of holes generated by impact ionization in the gate-to drain region. Electroluminescence represents a powerful tool in order to characterize not only hot electrons but also material properties. By using spatially resolved emission microscopy it is possible to show that the light due to cold electron/hole recombination is emitted between the gate and the source (low electric field region), while the contribution due to hot electrons is emitted between the gate and the drain (high electric field region). Deep-traps created in the device by hot carriers can be analysed by means of drain current deep level transient spectroscopy and by transconductance frequency dispersion. Cathodoluminescence, optical beam induced current, X-ray spectroscopy, electron energy loss spectroscopy in combination with a transmission electron microscopy are powerful tools in order to identify and localize surface modification following hot-electron stress tests.

The use of isoprene as a novel dopant in negative ion atmospheric pressure photoionization mass spectrometry coupled to high-performance liquid chromatography.

PubMed

Dousty, Faezeh; O'Brien, Rob

2015-06-15

As in the case with positive ion atmospheric pressure photoionization (PI-APPI), the addition of dopants significantly improves the sensitivity of negative ion APPI (NI-APPI). However, the research on dopant-assisted-NI-APPI has been quite limited compared to the studies on dopant-assisted PI-APPI. This work presents the potential of isoprene as a novel dopant for NI-APPI. Thirteen compounds, possessing suitable gas-phase ion energetic properties in order to make stable negative ions, were selected. Dopants were continuously introduced into a tee junction prior to the ion source through a fused-silica capillary, while analytes were directly injected into the same tee. Then both were mixed with the continuous solvent from high-performance liquid chromatography (HPLC), nebulized, and entered the source. The nebulized stream was analyzed by APPI tandem quadrupole mass spectrometry in the negative ion mode. The results obtained using isoprene were compared with those obtained by using toluene as a dopant and dopant-free NI-APPI. Isoprene enhanced the ionization intensities of the studied compounds, which were found to be comparable and, in some cases, more effective than toluene. The mechanisms leading to the observed set of negative analyte ions were also discussed. Because in NI-APPI, thermal electrons, which are produced during the photoionization of a dopant, are considered the main reagent ions, both isoprene and toluene promoted the ionization of analytes through the same mechanisms, as expected. Isoprene was shown to perform well as a novel dopant for NI-APPI. Isoprene has a high photoabsorption cross section in the VUV region; therefore, its photoionization leads to a highly effective production of thermal electrons, which further promotes the ionization of analytes. In addition, isoprene is environmentally benign and less toxic compared to currently used dopants. Copyright © 2015 John Wiley & Sons, Ltd.

Alternative Solvents and Technologies for Precision Cleaning of Aerospace Components

NASA Technical Reports Server (NTRS)

Grandelli, Heather; Maloney, Phillip; DeVor, Robert; Hintze, Paul

2014-01-01

Precision cleaning solvents for aerospace components and oxygen fuel systems, including currently used Vertrel-MCA, have a negative environmental legacy, high global warming potential, and have polluted cleaning sites. Thus, alternative solvents and technologies are being investigated with the aim of achieving precision contamination levels of less than 1 mg/sq ft. The technologies being evaluated are ultrasonic bath cleaning, plasma cleaning and supercritical carbon dioxide cleaning.

Is Having Low Motivation the Same as Not Having High Motivation? Comparing the CSAS-R and the SAAS-R

ERIC Educational Resources Information Center

McCoach, Betsy; Newton, Sarah D.; Siegle, Del; Baslanti, Ugur; Picho, Katherine

2016-01-01

The purpose of the current study was to examine the relationships among the Challenges to Scholastic Achievement Scale-Revised (CSAS-R) and The School Attitude Assessment Survey-Revised (SAAS-R) items and factors to determine whether the negative scales on the CSAS-R seemed to be measuring the same constructs as those that are measured on the…

Low-Cost, High-Performance Analog Optical Links

DTIC Science & Technology

2006-12-01

connected by tunnel junctions, which permit the forward conduction of current when they are reverse biased . Hence a key step in the development of the... bias voltage, where the measured IV is shown by the dotted curve. The common tunnel junction IV model assumed a triangular-shaped band structure. A... tunneling characteristics with negative differential resistance and a resistance under reverse bias around 12 Ω. This was higher than the previously grown

Negative pH, efflorescent mineralogy, and consequences for environmental restoration at the iron mountain superfund site, California

USGS Publications Warehouse

Nordstrom, D. Kirk; Alpers, Charles N.

1999-01-01

The Richmond Mine of the Iron Mountain copper deposit contains some of the most acid mine waters ever reported. Values of pH have been measured as low as -3.6, combined metal concentrations as high as 200 g/liter, and sulfate concentrations as high as 760 g/liter. Copious quantities of soluble metal sulfate salts such as melanterite, chalcanthite, coquimbite, rhomboclase, voltaite, copiapite, and halotrichite have been identified, and some of these are forming from negative-pH mine waters. Geochemical calculations show that, under a mine-plugging remediation scenario, these salts would dissolve and the resultant 600,000-m3 mine pool would have a pH of 1 or less and contain several grams of dissolved metals per liter, much like the current portal effluent water. In the absence of plugging or other at-source control, current weathering rates indicate that the portal effluent will continue for approximately 3,000 years. Other remedial actions have greatly reduced metal loads into downstream drainages and the Sacramento River, primarily by capturing the major acidic discharges and routing them to a lime neutralization plant. Incorporation of geochemical modeling and mineralogical expertise into the decision-making process for remediation can save time, save money, and reduce the likelihood of deleterious consequences.

Individual and environmental factors related to stage of change in exercise behavior: a cross-sectional study of female Japanese undergraduate students.

PubMed

Yasunaga, Akitomo; Kawano, Yukari; Kamahori, Yumiko; Noguchi, Kyoko

2014-01-01

The purpose of the current study was to examine the association between the level of exercise behavior and individual and environmental factors related to exercise behavior among female Japanese undergraduate students. The participants were 2482 female Japanese undergraduate students. Participants' level of exercise behavior was measured by the stage of change to exercise in the transtheoretical model. Individual and environmental factors related to exercise behavior were assessed using body mass index, self-efficacy, social support, perceived positive and negative aspects of exercise, perceived neighborhood environment, attitude toward physical education lessons in childhood and puberty, and depression. Scores for self-efficacy, social support, positive aspects of exercise, and perceived neighborhood environment were significantly higher among women who were more active compared with those who were inactive. On the other hand, scores for negative aspects of exercise and depression were greater among inactive women compared with those who were insufficiently active and/or active. In addition, past attitude toward exercise in primary school, junior high school, and high school was associated with current level of exercise behavior. This cross-sectional study confirmed that psychosocial and environmental factors were closely associated with level of exercise behavior among female Japanese undergraduate students.

"The internet is a mask": High School students' suggestions for preventing cyberbullying.

PubMed

Parris, Leandra N; Varjas, Kris; Meyers, Joel

2014-08-01

Interactions through technology have an important impact on today's youth. While some of these interactions are positive, there are concerns regarding students engaging in negative interactions like cyberbullying behaviors and the negative impact these behaviors have on others. The purpose of the current study was to explore participant suggestions for both students and adults for preventing cyberbullying incidents. Forty high school students participated in individual, semi-structured interviews. Participant experiences and perceptions were coded using constant comparative methods to illustrate ways in which students and adults may prevent cyberbullying from occurring within their school and community. Students reported that peers would benefit from increasing online security, as well as becoming more aware of their cyber-surroundings. Regarding adult-provided prevention services, participants often discussed that there is little adults can do to reduce cyberbullying. Reasons included the difficulties in restricting online behaviors or providing effective consequences. However, some students did discuss the use of in-school curricula while suggesting that adults blame people rather than technology as potential ways to prevent cyberbullying. Findings from the current study indicate some potential ways to improve adult efforts to prevent cyberbullying. These strategies include parent/teacher training in technology and cyberbullying, interventions focused more on student behavior than technology restriction, and helping students increase their online safety and awareness.

Negative pH, efflorescent mineralogy, and consequences for environmental restoration at the Iron Mountain Superfund site, California

PubMed Central

Nordstrom, D. Kirk; Alpers, Charles N.

1999-01-01

The Richmond Mine of the Iron Mountain copper deposit contains some of the most acid mine waters ever reported. Values of pH have been measured as low as −3.6, combined metal concentrations as high as 200 g/liter, and sulfate concentrations as high as 760 g/liter. Copious quantities of soluble metal sulfate salts such as melanterite, chalcanthite, coquimbite, rhomboclase, voltaite, copiapite, and halotrichite have been identified, and some of these are forming from negative-pH mine waters. Geochemical calculations show that, under a mine-plugging remediation scenario, these salts would dissolve and the resultant 600,000-m3 mine pool would have a pH of 1 or less and contain several grams of dissolved metals per liter, much like the current portal effluent water. In the absence of plugging or other at-source control, current weathering rates indicate that the portal effluent will continue for approximately 3,000 years. Other remedial actions have greatly reduced metal loads into downstream drainages and the Sacramento River, primarily by capturing the major acidic discharges and routing them to a lime neutralization plant. Incorporation of geochemical modeling and mineralogical expertise into the decision-making process for remediation can save time, save money, and reduce the likelihood of deleterious consequences. PMID:10097057

Dispersion, spatial growth rate, and start current of a Cherenkov free-electron laser with negative-index material

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

Wang, Yuanyuan; Wei, Yanyu; Jiang, Xuebing

We present an analysis of a Cherenkov free-electron laser based on a single slab made from negative-index materials. In this system, a flat electron beam with finite thickness travelling close to the surface of the slab interacts with the copropagating electromagnetic surface mode. The dispersion equation for a finitely thick slab is worked out and solved numerically to study the dispersion relation of surface modes supported by negative-index materials, and the calculations are in good agreement with the simulation results from a finite difference time domain code. We find that under suitable conditions there is inherent feedback in such amore » scheme due to the characteristics of negative-index materials, which means that the system can oscillate without external reflectors when the beam current exceeds a threshold value, i.e., start current. Using the hydrodynamic approach, we setup coupled equations for this system, and solve these equations analytically in the small signal regime to obtain formulas for the spatial growth rate and start current.« less

Protective behavioral strategies and negative alcohol-related consequences in college students.

PubMed

Araas, Teresa E; Adams, Troy B

2008-01-01

Alcohol abuse among college students is associated with a quality of life burden. The current study replicated and extended previous research on protective behavioral strategies (PBS) by examining relationships between PBS use and negative alcohol-related consequences. A national sample of 29,792 U.S. college students who completed the National College Health Assessment during spring 2004 was included. Using a retrospective analysis of cross-sectional data, relationships between PBS use and negative alcohol-related consequences were examined. Greater PBS use was associated with fewer negative alcohol-related consequences, while less frequent use of PBS was correlated with increased negative alcohol-related consequences. The current study findings strongly support expanded educational alcohol-intervention programs promoting greater PBS use aimed at reducing or completely alleviating negative alcohol-related consequences (e.g., BASICS, ASTP). Future research should further investigate such PBS-based intervention programs, examine the existence of latent PBS, and study use of combined PBS.