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Sample records for bias stress effects

  1. Effects of bias stress on ZnO nanowire field-effect transistors fabricated with organic gate nanodielectrics

    Science.gov (United States)

    Ju, Sanghyun; Janes, David B.; Lu, Gang; Facchetti, Antonio; Marks, Tobin J.

    2006-11-01

    The effects of bias stress (gate stress or drain stress) on nanowire field-effect transistor (NW-FET) stability were investigated as a function of stress bias and stress time. The n-channel NW-FETs used a nanoscopic self-assembled organic gate insulator, and each device contained a single ZnO nanowire. Before stress, the off current is limited by a leakage current in the 1nA range, which increases as the gate to source bias becomes increasingly negative. The devices also exhibited significant changes in threshold voltage (Vth) and off current over 500 repeated measurement sweeps. The leakage current was significantly reduced after gate stress, but not after drain stress. Vth variations observed upon successive bias sweeps for devices following gate stress or drain stress were smaller than the Vth variation of unstressed devices. These observations suggest that gate stress and drain stress modify the ZnO nanowire-gate insulator interface, which can reduce electron trapping at the surface and therefore reduce the off current levels and variations in Vth. These results confirm that gate and drain stresses are effective means to stabilize device operation and provide high performance transistors with impressive reliabilities.

  2. The effects of juvenile stress on anxiety, cognitive bias and decision making in adulthood: a rat model.

    Directory of Open Access Journals (Sweden)

    Nichola M Brydges

    Full Text Available Stress experienced in childhood is associated with an increased risk of developing psychiatric disorders in adulthood. These disorders are particularly characterized by disturbances to emotional and cognitive processes, which are not currently fully modeled in animals. Assays of cognitive bias have recently been used with animals to give an indication of their emotional/cognitive state. We used a cognitive bias test, alongside a traditional measure of anxiety (elevated plus maze, to investigate the effects of juvenile stress (JS on adulthood behaviour using a rodent model. During the cognitive bias test, animals were trained to discriminate between two reward bowls based on a stimulus (rough/smooth sandpaper encountered before they reached the bowls. One stimulus (e.g. rough was associated with a lower value reward than the other (e.g. smooth. Once rats were trained, their cognitive bias was explored through the presentation of an ambiguous stimulus (intermediate grade sandpaper: a rat was classed as optimistic if it chose the bowl ordinarily associated with the high value reward. JS animals were lighter than controls, exhibited increased anxiety-like behaviour in the elevated plus maze and were more optimistic in the cognitive bias test. This increased optimism may represent an optimal foraging strategy for these underweight animals. JS animals were also faster than controls to make a decision when presented with an ambiguous stimulus, suggesting altered decision making. These results demonstrate that stress in the juvenile phase can increase anxiety-like behaviour and alter cognitive bias and decision making in adulthood in a rat model.

  3. Bias-illumination stress effect in thin film transistors with a nitrogen low-doped IZO active layer

    Science.gov (United States)

    Cheremisin, Alexander B.; Kuznetsov, Sergey N.; Stefanovich, Genrikh B.

    2016-10-01

    The effect of ZnO and IZO moderate nitridation on the performance of thin film transistors (TFTs) has been studied by methods of transfer and capacitance-voltage characteristics, isochronal annealing and computer modeling. Layers of ZnO:N and IZO:N were prepared by reactive sputtering. It is shown that nitridation of the ZnO matrix up to a concentration of 9 at.% results in the deterioration of transistor parameters. However, nitridation of the IZO matrix does not impair a transistor’s static parameters and also provides enhanced performance reproducibility. An additional positive effect is manifested in the electrical stress stability of transistor characteristics at negative bias and positive bias in darkness. Negative bias illumination stress (NBIS) of IZO:N structures also causes TFTs’ degradation similar to that for IGZO devices. However, our observations of the NBIS effect have revealed the following important features. Holes trapped under NBIS could not be neutralized by electrons in the channel in the accumulation regime, thus indicating negligible interaction between positively-charged defects and the conduction band. In addition, trapped holes’ depopulation was performed by thermal activation with an isochronal annealing method. An activation energy of ˜0.8 eV was revealed which is interpreted as the energy level of defects above the valence-band maximum. The specified features do not correlate with the assumption of the key role of oxygen vacancies in NBIS that is extensively presented in literature.

  4. Combination of light-induced effect and gate bias stress in organic phototransistors

    Science.gov (United States)

    Liguori, R.; Sheets, W. C.; Bezzeccheri, E.; Facchetti, A.; Rubino, A.

    2016-05-01

    In this work, the photoresponse of pentacene-based thin film transistors fabricated with a photocurable polymer insulator was investigated under visible and ultraviolet illumination. A simple model was developed to distinguish a photoconductive and a photovoltaic effect, that is, a direct photocurrent and a current enhancement caused by a threshold voltage shift. The direction of the light-induced threshold translation is affected by measurement conditions (e.g. integration time and voltage range) and is related to the nature of the trap states, specifically those located in the pentacene film near the interface with the polymer. In particular, it was shown that, thanks to this phenomenon, the photosensitivity of the fabricated phototransistors could be modulated by the gate bias applied during illumination.

  5. Effect of indium low doping in ZnO based TFTs on electrical parameters and bias stress stability

    Energy Technology Data Exchange (ETDEWEB)

    Cheremisin, Alexander B., E-mail: acher612@gmail.com; Kuznetsov, Sergey N.; Stefanovich, Genrikh B. [Physico-Technical Department, Petrozavodsk State University, Petrozavodsk 185910 (Russian Federation)

    2015-11-15

    Some applications of thin film transistors (TFTs) need the bottom-gate architecture and unpassivated channel backside. We propose a simple routine to fabricate indium doped ZnO-based TFT with satisfactory characteristics and acceptable stability against a bias stress in ambient room air. To this end, a channel layer of 15 nm in thickness was deposited on cold substrate by DC reactive magnetron co-sputtering of metal Zn-In target. It is demonstrated that the increase of In concentration in ZnO matrix up to 5% leads to negative threshold voltage (V{sub T}) shift and an increase of field effect mobility (μ) and a decrease of subthreshold swing (SS). When dopant concentration reaches the upper level of 5% the best TFT parameters are achieved such as V{sub T} = 3.6 V, μ = 15.2 cm{sup 2}/V s, SS = 0.5 V/dec. The TFTs operate in enhancement mode exhibiting high turn on/turn off current ratio more than 10{sup 6}. It is shown that the oxidative post-fabrication annealing at 250{sup o}C in pure oxygen and next ageing in dry air for several hours provide highly stable operational characteristics under negative and positive bias stresses despite open channel backside. A possible cause of this effect is discussed.

  6. Effects of electron trapping and interface state generation on bias stress induced in indium-gallium-zinc oxide thin-film transistors

    Science.gov (United States)

    Han, Chang-Hoon; Kim, Sang-Sub; Kim, Kwang-Ryul; Baek, Do-Hyun; Kim, Sang-Soo; Choi, Byoung-Deog

    2014-08-01

    The electrical characteristics of bias temperature stress (BTS) induced in amorphous indium-gallium-zinc oxide thin-film transistors (a-IGZO TFTs) were studied. We analyzed the threshold voltage (VTH) shift on the basis of the effects of positive bias temperature stress (PBTS) and negative bias temperature stress (NBTS), and applied it to the stretched-exponential model. Both stress temperature and bias are considered as important factors in the electrical instabilities of a-IGZO TFTs, and the stretched-exponential equation is well fitted to the stress condition. VTH for the drain current-gate voltage (IDS-VGS) curve and flat-band voltage (VFB) for the capacitance-voltage (C-V) curve move in the positive direction when PBTS is induced. However, in the case of NBTS, they move slightly in the negative direction. To clarify the VTH shift phenomenon by electron and hole injection, the average effective energy barrier (Eτ) is extracted, and the extracted values of Eτ under PBTS and NBTS are about 1.33 and 2.25 eV, respectively. The oxide trap charges (Not) of PBTS and NBTS calculated by C-V measurement are 4.4 × 1011 and 1.49 × 1011 cm-2, respectively. On the other hand, the border trap charges of PBTS and NBTS are 6.7 × 108 and 1.7 × 109 cm-2, respectively. This indicates that the increased interface trap charge, after PBTS is induced, captures electrons during detrap processing from the border trap to the conduction band, valence band, and interface trap.

  7. The effect of asymmetrical electrode form after negative bias illuminated stress in amorphous IGZO thin film transistors

    Science.gov (United States)

    Su, Wan-Ching; Chang, Ting-Chang; Liao, Po-Yung; Chen, Yu-Jia; Chen, Bo-Wei; Hsieh, Tien-Yu; Yang, Chung-I.; Huang, Yen-Yu; Chang, Hsi-Ming; Chiang, Shin-Chuan; Chang, Kuan-Chang; Tsai, Tsung-Ming

    2017-03-01

    This paper investigates the degradation behavior of InGaZnO thin film transistors (TFTs) under negative bias illumination stress (NBIS). TFT devices with two different source and drain layouts were exanimated: one having a parallel format electrode and the other with UI format electrode. UI means that source/drain electrodes shapes is defined as a forked-shaped structure. The I-V curve of the parallel electrode exhibited a symmetric degradation under forward and reverse sweeping in the saturation region after 1000 s NBIS. In contrast, the I-V curve of the UI electrode structure under similar conditions was asymmetric. The UI electrode structure also shows a stretch-out phenomenon in its C-V measurement. Finally, this work utilizes the ISE-Technology Computer Aided Design (ISE-TCAD) system simulations, which simulate the electron field and IV curves, to analyze the mechanisms dominating the parallel and UI device degradation behaviors.

  8. Distinguishing Selection Bias and Confounding Bias in Comparative Effectiveness Research.

    Science.gov (United States)

    Haneuse, Sebastien

    2016-04-01

    Comparative effectiveness research (CER) aims to provide patients and physicians with evidence-based guidance on treatment decisions. As researchers conduct CER they face myriad challenges. Although inadequate control of confounding is the most-often cited source of potential bias, selection bias that arises when patients are differentially excluded from analyses is a distinct phenomenon with distinct consequences: confounding bias compromises internal validity, whereas selection bias compromises external validity. Despite this distinction, however, the label "treatment-selection bias" is being used in the CER literature to denote the phenomenon of confounding bias. Motivated by an ongoing study of treatment choice for depression on weight change over time, this paper formally distinguishes selection and confounding bias in CER. By formally distinguishing selection and confounding bias, this paper clarifies important scientific, design, and analysis issues relevant to ensuring validity. First is that the 2 types of biases may arise simultaneously in any given study; even if confounding bias is completely controlled, a study may nevertheless suffer from selection bias so that the results are not generalizable to the patient population of interest. Second is that the statistical methods used to mitigate the 2 biases are themselves distinct; methods developed to control one type of bias should not be expected to address the other. Finally, the control of selection and confounding bias will often require distinct covariate information. Consequently, as researchers plan future studies of comparative effectiveness, care must be taken to ensure that all data elements relevant to both confounding and selection bias are collected.

  9. Effects of defect creation on bidirectional behavior with hump characteristics of InGaZnO TFTs under bias and thermal stress

    Science.gov (United States)

    Im, Hwarim; Song, Hyunsoo; Jeong, Jaewook; Hong, Yewon; Hong, Yongtaek

    2015-03-01

    We investigated the hump characteristics of amorphous indium-gallium-zinc oxide thin-film transistors. The device showed a field effect mobility of 24.3 cm2 V-1 s-1, a threshold voltage (Vth) of 4.8 V, and a subthreshold swing of 120 mV/dec. Under positive gate bias stress, Vth showed bidirectional shift with a hump. Vth was positively and negatively shifted in the above-threshold and subthreshold regions, respectively. At high temperatures, Vth was more positively shifted without bidirectional shift. Under simultaneous drain bias stress (VDS,stress), the hump was maintained. However, the bidirectional shift was not observed with an increasing VDS,stress. The hump and positive shift are related to the defect creation of the shallow donor-like and deep-level acceptor-like states, respectively. We performed a two-dimensional device simulation to further investigate this phenomenon. By varying the peak values of the Gaussian shallow donor-like and deep acceptor-like states, we qualitatively confirmed the relationship between the two states and transfer curve changes.

  10. Effect of Reverse Substrate Bias on Degradation of Ultra-Thin Gate-Oxide n-Channel Metal-Oxide-Semiconductor Field-Effect Transistors under Different Stress Modes

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yao; XU Ming-Zhen; TAN Chang-Hua

    2005-01-01

    @@ Degradation of ultra-thin gate-oxide n-channel metal-oxide-semiconductor field-effect transistors with the halo structure has been studied under different stress modes with a reverse substrate bias. The device degradation under the same stress mode with different reverse substrate voltages has been characterized by monitoring the substrate current in a stressing process, which follows a simple power law. When the gate voltage is less than the critical value, the device degradation will first decrease and then increase with the increasing reverse sub strate voltage, otherwise, the device degradation will increase continuously. The critical value can be obtained by measuring the substrate current variation with the increases of reverse substrate voltage and gate voltage. The experimental results indicate that the stress mode with enhanced injection efficiency and smaller device degradation can be obtained when the gate voltage is less than the critical value with a proper reverse substratevoltage chosen.

  11. Enhance the lifetime and bias stress reliability in organic vertical transistor by UV/Ozone treatment

    Science.gov (United States)

    Lin, Hung-Cheng; Chang, Ming-Yu; Zan, Hsiao-Wen; Meng, Hsin-Fei; Chao, Yu-Chiang

    In this paper, we use UV/Ozone treatment to improve the lifetime and bias stress reliability of organic transistor with vertical channel. Even if vertical organic transistor exhibits better bias stress reliability than organic field effect transistor (OFET) due to bulk conduction mechanism, poor lifetime performance is still a challenge. Adding octadecyltrichlorosilane (OTS) to treat the vertical channel can reduce the trapping state and hence improve the bias stress ability. However, off-current is much higher after 6 days and lifetime performance is degraded. On the other hand, after 4000-s on-state bias stress, stable output current and on/off current ratio are demonstrated by using UV/Ozone to treat vertical channels. Threshold voltage shift is only -0.02 V which is much smaller than OFET with the same organic semiconductor material. Furthermore, the output current is also an order enhanced. Nevertheless, unlike device with OTS treatment, no obvious degradation is observed for UV/Ozone treated devices even after 170 days. With UV/Ozone treatment, the output current, bias stress reliability and lifetime were all improved. It makes vertical transistor become a promising device for the further application in display technology and flexible electronics.

  12. Exchange bias effect in alloys and compounds.

    Science.gov (United States)

    Giri, S; Patra, M; Majumdar, S

    2011-02-23

    The phenomenology of exchange bias effects observed in structurally single-phase alloys and compounds but composed of a variety of coexisting magnetic phases such as ferromagnetic, antiferromagnetic, ferrimagnetic, spin-glass, cluster-glass and disordered magnetic states are reviewed. The investigations on exchange bias effects are discussed in diverse types of alloys and compounds where qualitative and quantitative aspects of magnetism are focused based on macroscopic experimental tools such as magnetization and magnetoresistance measurements. Here, we focus on improvement of fundamental issues of the exchange bias effects rather than on their technological importance.

  13. The Serotonin Transporter Promoter Variant, Stress, and Attentional Biases in Middle Childhood.

    Science.gov (United States)

    Kotelnikova, Yuliya; LeMoult, Joelle; Mackrell, Sarah V M; Sheikh, Haroon I; Singh, Shiva M; Joormann, Jutta; Gotlib, Ian H; Hayden, Elizabeth P

    2016-09-01

    Although evidence suggests that 5-HTTLPR variants may shape risk for depression, the influence is likely complex, and involves effects on endophenotypes. We examined associations between 5-HTTLPR and biases in attention to affective stimuli in a sample of girls and a sample of both boys and girls. Children with at least one short (S) variant of the 5-HTTLPR polymorphism had lower positive attentional bias scores in both samples. This association was qualified by an interaction with stress in one sample, such that links between the S allele and decreased positive attentional bias was significant only when life stress was elevated. This difference in findings between the two samples was explained by sex differences in samples; the GXE interaction was significant only in boys. Findings are discussed in the context of sex differences in GXE.

  14. Bias-stress-induced instability of polymer thin-film transistor based on poly(3-hexylthiophene)

    OpenAIRE

    Liu, YR; Liao, R.; Lai, PT; Yao, RH

    2012-01-01

    A polymer thin-film transistor (PTFT) based on poly(3-hexylthiophene) (P3HT) is fabricated by a spin-coating process and characterized. Its bias-stress-induced instability during operation is investigated as a function of time and temperature. For negative gate-bias stress, the carrier mobility remains unchanged, the off-state current decreases, and the threshold voltage shifts toward the negative direction. On the other hand, for negative drain-bias stress, the carrier mobility decreases sli...

  15. Bias stress instability in organic transistors investigated by ac admittance measurements

    Science.gov (United States)

    Di Girolamo, F. V.; Barra, M.; Capello, V.; Oronzio, M.; Romano, C.; Cassinese, A.

    2010-06-01

    In this paper, the bias stress effect (BSE) in organic field-effect transistors has been analyzed by an alternative experimental approach based on ac admittance (Y=G+jωC) measurements. conductance (C) and capacitance (G) curves have been recorded as a function of frequency at different times of the bias stress experiments and simultaneously fitted through a transmission line circuit, able to separately model the conducting properties of the channel and contact regions. The determination of the time behavior of the model fitting parameters is assumed as the starting point for a quantitative analysis of the BSE occurrence. This experimental procedure clarifies that both channel resistance (Rch) and contact resistance (Rc) are largely affected by the BSE, while the channel capacitance (Cch), related to the charge accumulation sheet, and the contact capacitance (Cc) result almost unchanged.

  16. Negative bias-and-temperature stress-assisted activation of oxygen-vacancy hole traps in 4H-silicon carbide metal-oxide-semiconductor field-effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Ettisserry, D. P., E-mail: deva@umd.edu, E-mail: neil@umd.edu; Goldsman, N., E-mail: deva@umd.edu, E-mail: neil@umd.edu; Akturk, A. [Department of Electrical and Computer Engineering, University of Maryland, College Park, Maryland 20742 (United States); Lelis, A. J. [U.S. Army Research Laboratory, 2800 Powder Mill Road, Adelphi, Maryland 20783 (United States)

    2015-07-28

    We use hybrid-functional density functional theory-based Charge Transition Levels (CTLs) to study the electrical activity of near-interfacial oxygen vacancies located in the oxide side of 4H-Silicon Carbide (4H-SiC) power Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs). Based on the “amorphousness” of their local atomic environment, oxygen vacancies are shown to introduce their CTLs either within (permanently electrically active) or outside of (electrically inactive) the 4H-SiC bandgap. The “permanently electrically active” centers are likely to cause threshold voltage (V{sub th}) instability at room temperature. On the other hand, we show that the “electrically inactive” defects could be transformed into various “electrically active” configurations under simultaneous application of negative bias and high temperature stresses. Based on this observation, we present a model for plausible oxygen vacancy defects that could be responsible for the recently observed excessive worsening of V{sub th} instability in 4H-SiC power MOSFETs under high temperature-and-gate bias stress. This model could also explain the recent electrically detected magnetic resonance observations in 4H-SiC MOSFETs.

  17. Bias stress instability involving subgap state transitions in a-IGZO Schottky barrier diodes

    Science.gov (United States)

    Qian, Huimin; Wu, Chenfei; Lu, Hai; Xu, Weizong; Zhou, Dong; Ren, Fangfang; Chen, Dunjun; Zhang, Rong; Zheng, Youdou

    2016-10-01

    Vertical Schottky barrier diodes (SBDs) based on amorphous indium-gallium-zinc-oxide (a-IGZO) with either a top or bottom Schottky contact are fabricated by controlling the oxygen partial pressure during a-IGZO deposition. Although Au electrodes are employed for both Schottky and Ohmic contacts, it is found that Schottky contacts are preferentially formed on a-IGZO film in lower oxygen vacancy concentrations. The effect of negative bias stress on device performance is studied. The Schottky barrier height and series resistance of the a-IGZO SBD are found to increase upon negative bias stress, which is correlated with a reduction of the trap state and background carrier concentration within the a-IGZO film. A physical model based on subgap state transitions from ionized V\\text{O}2+ states to neutralized V O states is proposed to explain the observed electrical instability behavior.

  18. Effect of substrate bias on negative bias temperature instability of ultra-deep sub-micro p-channel metal-oxide-semiconductor field-effect transistors

    Institute of Scientific and Technical Information of China (English)

    Cao Yan-Rong; Hao Yue; Ma Xiao-Hua; Hu Shi-Gang

    2009-01-01

    The effect of substrate bias on the degradation during applying a negative bias temperature (NBT) stress is studied in this paper. With a smaller gate voltage stress applied, the degradation of negative bias temperature instability (NBTI) is enhanced, and there comes forth an inflexion point. The degradation pace turns larger when the substrate bias is higher than the inflexion point. The substrate hot holes can be injected into oxide and generate additional oxide traps, inducing an inflexion phenomenon. When a constant substrate bias stress is applied, as the gate voltage stress increases, an inflexion comes into being also. The higher gate voltage causes the electrons to tunnel into the substrate from the poly, thereby generating the electron-hole pairs by impact ionization. The holes generated by impact ionization and the holes from the substrate all can be accelerated to high energies by the substrate bias. More additional oxide traps can be produced, and correspondingly, the degradation is strengthened by the substrate bias. The results of the alternate stress experiment show that the interface traps generated by the hot holes cannot be annealed, which is different from those generated by common holes.

  19. Improvement in gate bias stress instability of amorphous indium-gallium-zinc oxide thin-film transistors using microwave irradiation

    Science.gov (United States)

    Jo, Kwang-Won; Cho, Won-Ju

    2014-11-01

    In this study, we evaluated the effects of microwave irradiation (MWI) post-deposition-annealing (PDA) treatment on the gate bias stress instability of amorphous indium-gallium-zinc oxide thin-film transistors (a-IGZO TFTs) and compared the results with a conventional thermal annealing PDA treatment. The MWI-PDA-treated a-IGZO TFTs exhibited enhanced electrical performance as well as improved long-term stability with increasing microwave power. The positive turn-on voltage shift (ΔVON) as a function of stress time with positive bias and varying temperature was precisely modeled on a stretched-exponential equation, suggesting that charge trapping is a dominant mechanism in the instability of MWI-PDA-treated a-IGZO TFTs. The characteristic trapping time and average effective barrier height for electron transport indicate that the MWI-PDA treatment effectively reduces the defects in a-IGZO TFTs, resulting in a superior resistance against gate bias stress.

  20. Negative Bias Temperature Instability "Recovery" under Negative Stress Voltage with Different Oxide Thicknesses

    Institute of Scientific and Technical Information of China (English)

    CAO Yan-Rong; MA Xiao-Hua; HAO Yue; ZHU Min-Bo; TIAN Wen-Chao; ZHANG Yue

    2011-01-01

    Different phenomena are observed under negative gate voltage stress which is smaller than the previous degradation stress in PMOSFETs with different oxide thicknesses. We adopt the real time method to make a point of the drain current to study the degradation and recovery of negative bias temperature instability (NBTI). For the device with thin oxide, recovery phenomenon appears when smaller negative voltage stress was applied, due to the more influencing oxide charges detrapping effects than the interface states. For the device with thick oxide, not recovery but degradation phenomenon comes forth. As many charges are trapped in the deeper position and higher energy level in the oxide, these charges can not be detrapped. Therefore, the effect of the charge detrapping is smaller than that of the interface states in the thick oxide. The degradation presents itself during the 'recovery' time.

  1. Theoretical and experimental on the Shupe-like bias caused by thermal stress of fiber optic gyros

    Science.gov (United States)

    Wang, Yueze; Ma, Lin; Zhao, Jingjing; Wu, Wei; Qiao, Liwei

    2016-10-01

    The fiber optic gyroscope has became to one of the most important sensors in developing due to light in quality, high accuracy, compact in dimension and long life and has played a very important role in both military and civil use. The fiber coil, as one of the most critical components in FOG, is extremely sensitive to changes in temperature. In this paper, at first, by studying the thermal stress of fiber optic gyros, the element model of the fiber coil was built based on the discrete mathematics formulae of Shupe error in FOG. Then based on the temperature distribution model mentioned above, the effects of the Shupe-like bias caused by thermal stress and the Shupe bias caused by temperature gradient are simulated. A turn-by-turn quantization bias error model is established. Theoretical analysis and experimental results show the Shupe-like bias caused by thermal stress and the Shupe bias caused by temperature gradient had seriously affected the temperature performance of FOG. By optimizing the winding method of fiber coil, the Shupe error of fiber coils can be reduced. At the same time, Shupe-like bias caused by thermal stress can be reduced too.

  2. Effects of Hf Incorporation on Negative Bias-Illumination Stress Stability in Hf-In-Zn-O Thin-Film Transistors

    Science.gov (United States)

    Kim, Sangwook; Park, Jae Chul; Kim, Dae Hwan; Lee, Jang-Sik

    2013-04-01

    In this study, highly reliable amorphous oxide semiconductor-based thin-film transistors (TFTs) were developed. The Hf concentration was systematically changed in the Hf-incorporated In-Zn-O (HIZO) TFTs, and Hf played an important role in determining the negative bias-illumination instability. The process parameters were optimized in order to obtain HIZO TFTs with an excellent stability. HIZO can be processed on a 6-in. wafer at low temperatures and is almost transparent in the visible range. Thus this material is promising for use in current TFTs as well as future transparent electronic device components with good electrical performance and excellent stability.

  3. Placebo effect studies are susceptible to response bias and to other types of biases

    DEFF Research Database (Denmark)

    Hróbjartsson, Asbjørn; Kaptchuk, Ted J; Miller, Franklin G

    2011-01-01

    Investigations of the effect of placebo are often challenging to conduct and interpret. The history of placebo shows that assessment of its clinical significance has a real potential to be biased. We analyze and discuss typical types of bias in studies on placebo.......Investigations of the effect of placebo are often challenging to conduct and interpret. The history of placebo shows that assessment of its clinical significance has a real potential to be biased. We analyze and discuss typical types of bias in studies on placebo....

  4. Placebo effect studies are susceptible to response bias and to other types of biases

    DEFF Research Database (Denmark)

    Hróbjartsson, Asbjørn; Kaptchuk, Ted J; Miller, Franklin G

    2011-01-01

    Investigations of the effect of placebo are often challenging to conduct and interpret. The history of placebo shows that assessment of its clinical significance has a real potential to be biased. We analyze and discuss typical types of bias in studies on placebo....

  5. Association between genes, stressful childhood events and processing bias in depression vulnerable individuals

    NARCIS (Netherlands)

    Vrijsen, J.N.; Oostrom, I.I.H. van; Arias-Vasquez, A.; Franke, B.; Becker, E.S.; Speckens, A.E.M.

    2014-01-01

    The brain-derived neurotrophic factor (BDNF) and catechol-O-methyltransferase (COMT) genes are relevant candidates for depression. Variation in these genes is associated with stress sensitivity and depressotypic cognitive biases. The interaction between genes and stressful events is considered as an

  6. Instability in threshold voltage and subthreshold behavior in Hf-In-Zn-O thin film transistors induced by bias-and light-stress

    Science.gov (United States)

    Ghaffarzadeh, Khashayar; Nathan, Arokia; Robertson, John; Kim, Sangwook; Jeon, Sanghun; Kim, Changjung; Chung, U.-In; Lee, Je-Hun

    2010-09-01

    Electrical bias and light stressing followed by natural recovery of amorphous hafnium-indium-zinc-oxide (HIZO) thin film transistors with a silicon oxide/nitride dielectric stack reveals defect density changes, charge trapping and persistent photoconductivity (PPC). In the absence of light, the polarity of bias stress controls the magnitude and direction of the threshold voltage shift (ΔVT), while under light stress, VT consistently shifts negatively. In all cases, there was no significant change in field-effect mobility. Light stress gives rise to a PPC with wavelength-dependent recovery on time scale of days. We observe that the PPC becomes more pronounced at shorter wavelengths.

  7. A stabilized, high stress self-biasing shape memory alloy actuator

    Science.gov (United States)

    Panton, B.; Zhou, Y. N.; Khan, M. I.

    2016-09-01

    A shape memory alloy (SMA) actuator that is biased internally would not need an external bias to achieve multiple actuation cycles. This would reduce cost, complexity and weight compared to standard one-way SMAs. The self-biasing actuators that have been developed to date have a lack of geometric and actuation stability. The current study developed a self-biasing NiTi actuator using a laser based vaporization process to alter the bulk composition of different regions. The martensitic laser processed NiTi region was the actuator, and un-processed austenitic base metal region was the internal bias. It was discovered that the laser processed region of the self-biasing actuator was unstable during high stress thermomechanical cycling due to the coarse grained microstructure. Cold-working of the half martensitic and half austenitic component resulted in similar deformation characteristics to single phase NiTi, which enabled the formation of a uniform nanocrystalline microstructure in both regions. When thermomechanically cycled 6000 times under stresses ranging from 180 to 400 MPa, it was discovered that this treated self-biasing actuator exhibited the stabilization behavior of traditional one-way actuators. This behavior was due to the uniform nanocrystalline microstructure, which impeded dislocation activity and ensured minimal plastic deformation.

  8. When bias binds: Effect of implicit outgroup bias on ingroup affiliation.

    Science.gov (United States)

    Jacoby-Senghor, Drew S; Sinclair, Stacey; Smith, Colin Tucker

    2015-09-01

    We tested a novel process we term implicit homophily in which perceivers' implicit outgroup bias shapes their affiliative responses toward ingroup targets with outgroup friends as a function of perceived similarity. Across 4 studies, we tested implicit homophily in the context of racial groups. We found that White participants with higher implicit anti-Black bias reported less affiliative responses toward White targets with Black friends compared with White targets with White friends, and this effect persisted above and beyond the effects of implicit pro-White bias and explicit racial bias (Studies 1-3). We further found evidence that this relationship between implicit anti-Black bias and affiliation exists because participants infer how comfortable targets are around outgroup members (Preliminary Study) and use this information to infer similarity on this dimension (Studies 1-3). Our findings also suggested that stigma transference and expectancy violation were not viable alternative mediators (Preliminary Study and Study 1). Finally, women's implicit anti-Black bias predicted their likelihood of having Facebook friends with Black friends, providing ecological and behavioral evidence of implicit homophily (Study 4). Implications for research on stigma by association, extended contact, affiliation, and network formation are discussed.

  9. Investigating new process-focused treatments for posttraumatic stress disorder: attentional bias modification and mindfulness-based cognitive therapy

    OpenAIRE

    Schoorl, Stephanie Maartje Desiree (Maartje)

    2013-01-01

    We investigated the effects of two novel treatments for posttraumatic stress disorder (PTSD). The first treatment is Attentional Bias Modification (ABM). This treatment for anxiety disorders has become quite popular in a relatively short time and was featured in recent articles in the New York Times and The Economist. ABM is a brief, computerized treatment in which patients are trained to keep their attention away from the threatening stimuli from which they automatically attend. Since attent...

  10. Perceived stress and risk of ischemic heart disease: causation or bias?

    DEFF Research Database (Denmark)

    Nielsen, Naja Rod; Kristensen, Tage S; Prescott, Eva;

    2006-01-01

    2000, and fewer than 0.1% were lost to follow-up. During follow-up, 2316 individuals were diagnosed with ischemic heart disease. RESULTS: High levels of stress were associated with slightly higher risk of incident ischemic heart disease in both women (hazard ratio = 1.23; 95% confidence interval = 1......BACKGROUND: It is unclear whether the commonly recognized link between stress and cardiovascular disease is causal or the result of reporting bias. The objective of this study was to address the association between perceived stress and first incidence of ischemic heart disease and to evaluate...... the suggested reporting bias by addressing subdiagnoses of ischemic heart disease separately. METHODS: The 11,839 men and women who participated in the Copenhagen City Heart Study were at baseline (1981-1983) asked about their stress level. The participants were followed in nationwide registries until the year...

  11. Long-term changes in cognitive bias and coping response as a result of chronic unpredictable stress during adolescence

    Directory of Open Access Journals (Sweden)

    Lauren eChaby

    2013-07-01

    Full Text Available Animals that experience adverse events in early life often have life-long changes to their physiology and behavior. Long-term effects of stress during early life have been studied extensively, but less attention has been given to the consequences of negative experiences solely during the adolescent phase. Adolescence is a particularly sensitive period of life when regulation of the glucocorticoid stress hormone response matures and specific regions in the brain undergo considerable change. Aversive experiences during this time might, therefore, be expected to generate long-term consequences for the adult phenotype. Here we investigated the long-term effects of exposure to chronic unpredictable stress during adolescence on adult decision making, coping response, cognitive bias, and exploratory behavior in rats. Rats exposed to chronic unpredictable stress (e.g. isolation, crowding, cage tilt were compared to control animals that were maintained in standard, predictable conditions throughout development. Unpredictable stress during adolescence resulted in a suite of long-term behavioral and cognitive changes including a negative cognitive bias (F1,12 = 5.000, P < 0.05, altered coping response (T1,14 = 2.216, P = 0.04, and accelerated decision making (T1,14 = 3.245, P = 0.01. Exposure to chronic stress during adolescence also caused a short-term increase in boldness behaviors; in a novel object test 15 days after the last stressor, animals exposed to chronic unpredictable stress had decreased latencies to leave a familiar shelter and approach a novel object (T1,14 = 2.240, P = 0.04; T1,14 = 2.419, P = 0.03, respectively. The results showed that stress during adolescence has long-term impacts on behavior and cognition that affect the interpretation of ambiguous stimuli, behavioral response to adverse events, and how animals make decisions. Stress during adolescence also induced short-term changes in the way animals moved around a novel environment.

  12. Interpreting anomalies observed in oxide semiconductor TFTs under negative and positive bias stress

    Directory of Open Access Journals (Sweden)

    Jong Woo Jin

    2016-08-01

    Full Text Available Oxide semiconductor thin-film transistors can show anomalous behavior under bias stress. Two types of anomalies are discussed in this paper. The first is the shift in threshold voltage (VTH in a direction opposite to the applied bias stress, and highly dependent on gate dielectric material. We attribute this to charge trapping/detrapping and charge migration within the gate dielectric. We emphasize the fundamental difference between trapping/detrapping events occurring at the semiconductor/dielectric interface and those occurring at gate/dielectric interface, and show that charge migration is essential to explain the first anomaly. We model charge migration in terms of the non-instantaneous polarization density. The second type of anomaly is negative VTH shift under high positive bias stress, with logarithmic evolution in time. This can be argued as electron-donating reactions involving H2O molecules or derived species, with a reaction rate exponentially accelerated by positive gate bias and exponentially decreased by the number of reactions already occurred.

  13. Unified nonequilibrium dynamical theory for exchange bias and training effects

    Institute of Scientific and Technical Information of China (English)

    Zhang Kai-Cheng; Liu Bang-Gui

    2009-01-01

    We have investigated the exchange bias and training effect in the ferromagnetie/antiferromagnetic (FM/AF)heterostructures using a unified Monte Carlo dynamical approach. The magnetization of the uncompensated AF layer is still open after the first field cycling is finished. Our simulated results show obvious shift of hysteresis loops (exchange bias) and cycling dependence of exchange bias (training effect) when the temperature is below 45 K. The exchange bias field decreases with decreasing cooling rate or increasing temperature and the number of the field cycling. Essentially,these two effects can be explained on the basis of the microscopical coexistence of both reversible and irreversible moment reversals of the AF domains. Our simulations are useful to understand the real magnetization dynamics of such magnetic heterostructures.

  14. Context effects and observer bias--implications for forensic odontology.

    Science.gov (United States)

    Page, Mark; Taylor, Jane; Blenkin, Matt

    2012-01-01

    Psychologists have long recognized the effects of contextual and extraneous information on decision making. Such information renders the subject susceptible to both motivational and cognitive bias; yet, it is difficult to assess the extent to which these influence forensic odontologists opinions as there have been no studies to date on this subject. This article explores the various types of contextual effects and biasing influences that potentially impact on the analysis of bitemarks in forensic odontology. It appears that the current practice of bitemark analysis is rich in sources of potentially biasing influences. In addition to the fundamental recognition that some form of bias is likely to exist, ways in which these should be minimized include: separation of the collection and analysis phases; limiting the amount of contextual information available to the odontologist responsible for the analysis; and ensuring that evidence that is ambiguous or of poor quality is identified as such prior to analysis.

  15. Effects of constant voltage and constant current stress in PCBM:P3HT solar cells

    DEFF Research Database (Denmark)

    Cester, Andrea; Rizzo, Aldo; Bazzega, A.

    2015-01-01

    The aimof this work is the investigation of forward and reverse bias stress effects, cell self-heating and annealing in roll coated organic solar cells with PCBM:P3HT active layer. In reverse bias stress cells show a constant degradation over time. In forward current stress cells alternate degrad...

  16. Ferromagnetic behavior and exchange bias effect in akaganeite nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Tadic, Marin, E-mail: marint@vinca.rs [Condensed Matter Physics Laboratory, Vinca Institute of Nuclear Science, University of Belgrade, P.O. Box 522, 11001 Belgrade (Serbia); Milosevic, Irena; Motte, Laurence [Laboratoire CSPBAT, UMR 7244 CNRS Université Paris 13, 93017 Bobigny Cedex (France); Kralj, Slavko [Department for Materials Synthesis, Jožef Stefan Institute, Jamova 39, 1000 Ljubljana (Slovenia); Saboungi, Marie-Louise [CNRS, University of Orleans, F-45071 Orleans 2 (France); IMPMC, Sorbonne Univ-UPMC Univ Paris 06, UMR CNRS 7590, Museum National d' Histoire Naturelle, IRD UMR 206, 4 Place Jussieu, F-75005 Paris (France)

    2015-05-04

    We report ferromagnetic-like properties and exchange bias effect in akaganeite (β-FeOOH) nanorods. They exhibit a Néel temperature T{sub N} = 259 K and ferromagnetic-like hysteresis behavior both below and above T{sub N}. An exchange bias effect is observed below T{sub N} and represents an interesting behavior for akaganeite nanorods. These results are explained on the basis of a core-shell structure in which the core has bulk akaganeite magnetic properties (i.e., antiferromagnetic ordering) while the shell exhibits a disordered spin state. Thus, the nanorods show ferromagnetic properties and an exchange bias effect at the same time, increasing their potential for use in practical applications.

  17. Improving positive and negative bias illumination stress stability in parylene passivated IGZO transistors

    Science.gov (United States)

    Kiazadeh, Asal; Gomes, Henrique L.; Barquinha, Pedro; Martins, Jorge; Rovisco, Ana; Pinto, Joana V.; Martins, Rodrigo; Fortunato, Elvira

    2016-08-01

    The impact of a parylene top-coating layer on the illumination and bias stress instabilities of indium-gallium-zinc oxide thin-film transistors (TFTs) is presented and discussed. The parylene coating substantially reduces the threshold voltage shift caused by continuous application of a gate bias and light exposure. The operational stability improves by 75%, and the light induced instability is reduced by 35%. The operational stability is quantified by fitting the threshold voltage shift with a stretched exponential model. Storage time as long as 7 months does not cause any measurable degradation on the electrical performance. It is proposed that parylene plays not only the role of an encapsulation layer but also of a defect passivation on the top semiconductor surface. It is also reported that depletion-mode TFTs are less sensitive to light induced instabilities. This is attributed to a defect neutralization process in the presence of free electrons.

  18. Josephson effects in an alternating current biased transition edge sensor

    CERN Document Server

    Gottardi, Luciano; Akamatsu, Hiroki; van der Kuur, Jan; Bruijn, Marcel P; Hartog, Roland H den; Hijmering, Richard; Khosropanah, Pourya; Lambert, Colin; van der Linden, Anton J; Ridder, Marcel L; Suzuki, Toyo; Gao, Jan R

    2016-01-01

    We report the experimental evidence of the ac Josephson effect in a transition edge sensor (TES) operating in a frequency domain multiplexer and biased by ac voltage at MHz frequencies. The effect is observed by measuring the non-linear impedance of the sensor. The TES is treated as a weakly linked superconducting system and within the resistively shunted junction model framework. We provide a full theoretical explanation of the results by finding the analytic solution of the non-inertial Langevian equation of the system and calculating the non-linear response of the detector to a large ac bias current in the presence of noise.

  19. Heterogeneous Causal Effects and Sample Selection Bias

    DEFF Research Database (Denmark)

    Breen, Richard; Choi, Seongsoo; Holm, Anders

    2015-01-01

    The role of education in the process of socioeconomic attainment is a topic of long standing interest to sociologists and economists. Recently there has been growing interest not only in estimating the average causal effect of education on outcomes such as earnings, but also in estimating how cau......, and we illustrate our arguments and our method using National Longitudinal Survey of Youth 1979 (NLSY79) data....

  20. Estimating heat stress from climate-based indicators: present-day biases and future spreads in the CMIP5 global climate model ensemble

    Science.gov (United States)

    Zhao, Y.; Ducharne, A.; Sultan, B.; Braconnot, P.; Vautard, R.

    2015-08-01

    The increased exposure of human populations to heat stress is one of the likely consequences of global warming, and it has detrimental effects on health and labor capacity. Here, we consider the evolution of heat stress under climate change using 21 general circulation models (GCMs). Three heat stress indicators, based on both temperature and humidity conditions, are used to investigate present-day model biases and spreads in future climate projections. Present day estimates of heat stress indicators from observational data shows that humid tropical areas tend to experience more frequent heat stress than other regions do, with a total frequency of heat stress 250-300 d yr-1. The most severe heat stress is found in the Sahel and south India. Present-day GCM simulations tend to underestimate heat stress over the tropics due to dry and cold model biases. The model based estimates are in better agreement with observation in mid to high latitudes, but this is due to compensating errors in humidity and temperature. The severity of heat stress is projected to increase by the end of the century under climate change scenario RCP8.5, reaching unprecedented levels in some regions compared with observations. An analysis of the different factors contributing to the total spread of projected heat stress shows that spread is primarily driven by the choice of GCMs rather than the choice of indicators, even when the simulated indicators are bias-corrected. This supports the utility of the multi-model ensemble approach to assess the impacts of climate change on heat stress.

  1. Temperature effect on negative bias-induced instability of HfInZnO amorphous oxide thin film transistor

    Science.gov (United States)

    Kwon, Dae Woong; Kim, Jang Hyun; Chang, Ji Soo; Kim, Sang Wan; Kim, Wandong; Park, Jae Chul; Song, Ihun; Kim, Chang Jung; Jung, U. In; Park, Byung-Gook

    2011-02-01

    Negative bias-induced instability of amorphous hafnium indium zinc oxide (α-HIZO) thin film transistors (TFTs) was investigated at various temperatures. In order to examine temperature-induced effects, fabricated TFTs with different combinations of gate insulator and gate metal were stressed by a negative gate bias at various temperatures. As a result, it is proved that negative bias-induced hole-trapping in the gate insulators and temperature-enhanced electron injection from the gate metals occurs at the same time at all temperatures, and the instability of HIZO TFT is more affected by the dominant factor out of the two mechanisms.

  2. Memory effect versus exchange bias for maghemite nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Nadeem, K., E-mail: kashif.nadeem@iiu.edu.pk [Materials Research Laboratory, Department of Physics, International Islamic University, Islamabad (Pakistan); Krenn, H. [Institute of Physics, Karl-Franzens University Graz, Universitätsplatz 5, A-8010 Graz (Austria); Szabó, D.V. [Karlsruhe Institute of Technology, Institute for Applied Materials, 76344 Eggenstein-Leopoldshafen (Germany)

    2015-11-01

    We studied the temperature dependence of memory and exchange bias effects and their dependence on each other in maghemite (γ-Fe{sub 2}O{sub 3}) nanoparticles by using magnetization studies. Memory effect in zero field cooled process in nanoparticles is a fingerprint of spin-glass behavior which can be due to i) surface disordered spins (surface spin-glass) and/or ii) randomly frozen and interacting nanoparticles core spins (super spin-glass). Temperature region (25–70 K) for measurements has been chosen just below the average blocking temperature (T{sub B}=75 K) of the nanoparticles. Memory effect (ME) shows a non-monotonous behavior with temperature. It shows a decreasing trend with decreasing temperature and nearly vanishes below 30 K. However it also decreased again near the blocking temperature of the nanoparticles e.g., 70 K. Exchange bias (EB) in these nanoparticles arises due to core/shell interface interactions. The EB increases sharply below 30 K due to increase in core/shell interactions, while ME starts vanishing below 30 K. We conclude that the core/shell interface interactions or EB have not enhanced the ME but may reduce it in these nanoparticles. - Highlights: • We studied the T-dependent memory and exchange bias (EB) effects in maghemite nanoparticles. • EB causes spin-canting at the core/shell interface which may reduces the memory effect (ME). • Interface interactions does not increase the ME in these nanoparticles.

  3. Cognitive Bias Modification Training in Adolescents: Effects on Interpretation Biases and Mood

    Science.gov (United States)

    Lothmann, Claudia; Holmes, Emily A.; Chan, Stella W. Y.; Lau, Jennifer Y. F.

    2011-01-01

    Background: Negative biases in the interpretation of ambiguous material have been linked to anxiety and mood problems. Accumulating data from adults show that positive and negative interpretation styles can be induced through cognitive bias modification (CBM) paradigms with accompanying changes in mood. Despite the therapeutic potential of…

  4. A Procedure to Assess Interviewer Effects on Nonresponse Bias

    Directory of Open Access Journals (Sweden)

    Geert Loosveldt

    2014-02-01

    Full Text Available It is generally accepted that interviewers have a considerable effect on survey response. The difference between response success and failure does not only affect the response rate, but can also influence the composition of the realized sample or respondent set, and consequently introduce nonresponse bias. To measure these two different aspects of the obtained sample, response propensities will be used. They have an aggregate mean and variance that can both be used to construct quality indicators for the obtained sample of respondents. As these propensities can also be measured on the interviewer level, this allows evaluation of the interviewer group and of the extent to which individual interviewers contribute to a biased respondent set. In this article, a procedure based on a multilevel model with random intercepts and random slopes is elaborated and illustrated. The results show that the procedure is informative to detect influential interviewers with an impact on nonresponse basis.

  5. Effect of bias voltage on microstructure and mechanical properties of arc evaporated (Ti, Al)N hard coatings

    Indian Academy of Sciences (India)

    F Aliaj; N Syla; S Avdiaj; T Dilo

    2013-06-01

    In the present study, authors report on the effect that substrate bias voltage has on the microstructure and mechanical properties of (Ti, Al)N hard coatings deposited with cathodic arc evaporation (CAE) technique. The coatings were deposited from a Ti0.5Al0.5 powder metallurgical target in a reactive nitrogen atmosphere at three different bias voltages: UB = −25, −50 and −100 V. The coatings were characterized in terms of compositional, microstructural and mechanical properties. Microstructure of the coatings was investigated with the aid of X-ray diffraction in glancing angle mode, which revealed information on phase composition, crystallite size, stress-free lattice parameter and residual stress. Mechanical properties were deduced from nano-indentation measurements. The residual stress in all the coatings was compressive and increased with increasing bias voltage in a manner similar to that reported in literature for Ti–Al–N coatings deposited with CAE. The bias voltage was also found to significantly influence the phase composition and crystallite size. At −25 V bias voltage the coating was found in single phase fcc-(Ti, Al)N and with relatively large crystallites of ∼9 nm. At higher bias voltages (−50 and −100 V), the coatings were found in dual phase fcc-(Ti, Al)N and fcc-AlN and the size of crystallites reduced to approximately 5 nm. The reduction of crystallite size and the increase of compressive residual stress with increasing bias voltage both contributed to an increase in hardness of the coatings.

  6. Media Bias

    OpenAIRE

    Sendhil Mullainathan; Andrei Shleifer

    2002-01-01

    There are two different types of media bias. One bias, which we refer to as ideology, reflects a news outlet's desire to affect reader opinions in a particular direction. The second bias, which we refer to as spin, reflects the outlet's attempt to simply create a memorable story. We examine competition among media outlets in the presence of these biases. Whereas competition can eliminate the effect of ideological bias, it actually exaggerates the incentive to spin stories.

  7. The effect of academic stress and attachment stress on stress-eaters and stress-undereaters.

    Science.gov (United States)

    Emond, Michael; Ten Eycke, Kayla; Kosmerly, Stacey; Robinson, Adele Lafrance; Stillar, Amanda; Van Blyderveen, Sherry

    2016-05-01

    It is well established that stress is related to changes in eating patterns. Some individuals are more likely to increase their overall food intake under conditions of stress, whereas others are more likely to consume less food when stressed. Attachment style has been linked to disordered eating and eating disorders; however, comparisons of eating behaviors under attachment versus other types of stress have yet to be explored. The present laboratory study examined the eating patterns in self-identified stress-undereaters and stress-eaters under various types of stress. More specifically, the study examined the effects of academic and attachment stress on calorie, carbohydrate and sugar consumption within these two groups. Under the guise of critiquing student films, university students viewed either one of two stress-inducing videos (academic stress or attachment stress, both designed to be emotionally arousing) or a control video (designed to be emotionally neutral), and their food intake was recorded. Results demonstrated that the video manipulations were effective in inducing stress. Differential patterns of eating were noted based on group and stress condition. Specifically, stress-undereaters ate fewer calories, carbohydrates and sugars than stress-eaters in the academic stress condition, but not in the attachment stress or control condition. Findings suggest that specific types of stressors may influence eating behaviors differently.

  8. Posttraumatic stress disorder symptoms, intimate partner violence perpetration, and the mediating role of shame processing bias.

    Science.gov (United States)

    Sippel, Lauren M; Marshall, Amy D

    2011-10-01

    Posttraumatic stress disorder (PTSD) may produce internal "threats to the self," which generate shame. Shame is theoretically and empirically linked to intimate partner violence (IPV) perpetration. We examined relations among PTSD, cognitive processing of shame-relevant information, and IPV perpetration. Forty-seven community participants completed an emotional Stroop task with shame-relevant and neutral words. Stimuli were presented supraliminally (i.e., until vocal response) and subliminally (i.e., below an individualized threshold of conscious awareness). Facilitated color-naming of shame-relevant words (thought to reflect congruence between shame and self-schemas) mediated the relation between PTSD severity and IPV perpetration frequency. Mediation results for subliminal stimuli suggest that biased processing of shame cues may occur preconsciously and potentially catalyze processes (i.e., expectations of rejection in ambiguous situations with one's partner; avoidance that minimizes discomfort and protects self-image) that lead to IPV perpetration. Psychotherapeutic approaches to PTSD and IPV should consider the role of facilitated processing of shame cues.

  9. Investigation of negative bias temperature instability dependence on fin width of silicon-on-insulator-fin-based field effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Young, Chadwin D., E-mail: chadwin.young@utdallas.edu; Wang, Zhe [Materials Science and Engineering, University of Texas at Dallas, 800 W. Campbell Road, Richardson, Texas 75080 (United States); Neugroschel, Arnost [Department of Electrical and Computer Enginering, University of Florida, Gainesville, Florida 32611 (United States); Majumdar, Kausik; Matthews, Ken; Hobbs, Chris [SEMATECH, Albany, New York 12203 (United States)

    2015-01-21

    The fin width dependence of negative bias temperature instability (NBTI) of double-gate, fin-based p-type Field Effect Transistors (FinFETs) fabricated on silicon-on-insulator (SOI) wafers was investigated. The NBTI degradation increased as the fin width narrowed. To investigate this phenomenon, simulations of pre-stress conditions were employed to determine any differences in gate oxide field, fin band bending, and electric field profile as a function of the fin width. The simulation results were similar at a given gate stress bias, regardless of the fin width, although the threshold voltage was found to increase with decreasing fin width. Thus, the NBTI fin width dependence could not be explained from the pre-stress conditions. Different physics-based degradation models were evaluated using specific fin-based device structures with different biasing schemes to ascertain an appropriate model that best explains the measured NBTI dependence. A plausible cause is an accumulation of electrons that tunnel from the gate during stress into the floating SOI fin body. As the fin narrows, the sidewall device channel moves in closer proximity to the stored electrons, thereby inducing more band bending at the fin/dielectric interface, resulting in a higher electric field and hole concentration in this region during stress, which leads to more degradation. The data obtained in this work provide direct experimental proof of the effect of electron accumulation on the threshold voltage stability in FinFETs.

  10. Electrochemical migration in electronics: effect of contamination and bias conditions

    DEFF Research Database (Denmark)

    Verdingovas, Vadimas; Jellesen, Morten Stendahl; Ambat, Rajan

    – all together influence susceptibility of electronic PCBA to corrosion. When electronics is operating under humid conditions, the cleanliness of the PCBA becomes essential, since corrosion related failures in electronics can occur at extremely low levels of moisture and contamination. A synergetic...... climate, contamination, and bias conditions. In this work, the effect of ionic contamination such as sodium chloride and weak organic acids, as they are used in no-clean fluxes, was studied under water droplet and humidity elevation at room temperature conditions. The effect of pH and tin ion dissolution...... droplet. Overall the tendency of increase in time to electrochemical migration with decrease of duty cycle was observed. The testing of the printed circuit boards under humid conditions showed a correlation between the hygroscopic property of contaminants and leakage current measured on the boards...

  11. Surprise, Memory, and Retrospective Judgment Making: Testing Cognitive Reconstruction Theories of the Hindsight Bias Effect

    Science.gov (United States)

    Ash, Ivan K.

    2009-01-01

    Hindsight bias has been shown to be a pervasive and potentially harmful decision-making bias. A review of 4 competing cognitive reconstruction theories of hindsight bias revealed conflicting predictions about the role and effect of expectation or surprise in retrospective judgment formation. Two experiments tested these predictions examining the…

  12. Improvement in reliability of amorphous indium-gallium-zinc oxide thin-film transistors with Teflon/SiO2 bilayer passivation under gate bias stress

    Science.gov (United States)

    Fan, Ching-Lin; Tseng, Fan-Ping; Li, Bo-Jyun; Lin, Yu-Zuo; Wang, Shea-Jue; Lee, Win-Der; Huang, Bohr-Ran

    2016-02-01

    The reliability of amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistors (TFTs) with Teflon/SiO2 bilayer passivation prepared under positive and negative gate bias stresses (PGBS and NGBS, respectively) was investigated. Heavier electrical degradation was observed under PGBS than under NGBS, indicating that the environmental effects under PGBS are more evident than those under NGBS. The device with bilayer passivation under PGBS shows two-step degradation. The positive threshold voltage shifts during the initial stressing period (before 500 s), owing to the charges trapped in the gate insulator or at the gate insulator/a-IGZO active layer interface. The negative threshold voltage shift accompanies the increase in subthreshold swing (SS) for the continuous stressing period (after 500 s) owing to H2O molecules from ambience diffused within the a-IGZO TFTs. It is believed that Teflon/SiO2 bilayer passivation can effectively improve the reliability of the a-IGZO TFTs without passivation even though the devices are stressed under gate bias.

  13. Behavioral Biases of Individual Investors: The Effect of Anchoring

    Directory of Open Access Journals (Sweden)

    Salma Zaiane

    2015-03-01

    Full Text Available The objective of this paper is to investigate the presence of the anchoring bias in the financial decision making of individual investors. A survey study is carried out to find out how the studied bias affects the investment behavior on the Tunisian stock market. The survey is for exploratory purpose and it is based on multiple factorial correspondence analyses. The results reveal that Tunisian investors do not suffer from the anchoring bias.

  14. Reliability tests of electroless barriers against copper diffusion under bias-temperature stress with n- and p-type substrates

    Science.gov (United States)

    Ueno, Kazuyoshi; Fujishima, Shota; Yamashita, Makoto; Mitsumori, Akiyoshi

    2016-05-01

    To investigate the similarity and difference of substrate conduction type in the time-dependent dielectric breakdown (TDDB) tests for the barrier integrity against Cu diffusion under bias-temperature stress (BTS), the TDDB reliability of electroless NiB and CoWP/NiB was determined by metal oxide semiconductor (MOS) structures on n-type Si (n-Si) substrates, and the test results were compared with those using p-type Si (p-Si) substrates. The TDDB results and mechanism were observed to be qualitatively the same as Cu diffusion for both conduction types. However, the TDDB lifetime using p-Si was found to be potentially shorter because of the reverse bias conditions than that using n-Si under the forward bias conditions.

  15. Plasma acceleration using a radio frequency self-bias effect

    Energy Technology Data Exchange (ETDEWEB)

    Rafalskyi, D.; Aanesland, A. [Laboratoire de Physique des Plasmas (CNRS, Ecole Polytechnique, Sorbonne Universités, UPMC Univ Paris 06, Univ Paris-Sud), Ecole Polytechnique, 91128 Palaiseau (France)

    2015-06-15

    In this work plasma acceleration using a RF self-bias effect is experimentally studied. The experiments are conducted using a novel plasma accelerator system, called Neptune, consisting of an inductively coupled plasma source and a RF-biased set of grids. The plasma accelerator can operate in a steady state mode, producing a plasma flow with separately controlled plasma flux and velocity without any magnetic configuration. The operating pressure at the source output is as low as 0.2 mTorr and can further be decreased. The ion and electron flows are investigated by measuring the ion and electron energy distribution functions both space resolved and with different orientations with respect to the flow direction. It is found that the flow of electrons from the source is highly anisotropic and directed along the ion flow and this global flow of accelerated plasma is well localized in the plasma transport chamber. The maximum flux is about 7.5·10{sup 15} ions s{sup −1} m{sup −2} (at standard conditions) on the axis and decreasing to almost zero at a radial distances of more than 15 cm from the flow axis. Varying the RF acceleration voltage in the range 20–350 V, the plasma flow velocity can be changed between 10 and 35 km/s. The system is prospective for different technology such as space propulsion and surface modification and also interesting for fundamental studies for space-related plasma simulations and investigation of the dynamo effect using accelerated rotating plasmas.

  16. No effects of psychosocial stress on intertemporal choice.

    Directory of Open Access Journals (Sweden)

    Johannes Haushofer

    Full Text Available Intertemporal choices - involving decisions which trade off instant and delayed outcomes - are often made under stress. It remains unknown, however, whether and how stress affects intertemporal choice. We subjected 142 healthy male subjects to a laboratory stress or control protocol, and asked them to make a series of intertemporal choices either directly after stress, or 20 minutes later (resulting in four experimental groups. Based on theory and evidence from behavioral economics and cellular neuroscience, we predicted a bidirectional effect of stress on intertemporal choice, with increases in impatience or present bias immediately after stress, but decreases in present bias or impatience when subjects are tested 20 minutes later. However, our results show no effects of stress on intertemporal choice at either time point, and individual differences in stress reactivity (changes in stress hormone levels over time are not related to individual differences in intertemporal choice. Together, we did not find support for the hypothesis that psychosocial laboratory stressors affect intertemporal choice.

  17. Giant magnetoelectric effect in self-biased laminates under zero magnetic field

    Science.gov (United States)

    Li, Menghui; Wang, Zhiguang; Wang, Yaojin; Li, Jiefang; Viehland, D.

    2013-02-01

    A giant magnetoelectric (ME) effect in self-biased annealed Metglas/Pb(Zr,Ti)O3/Metglas laminates under zero magnetic bias is reported. The remanent magnetization was increased by annealing Metglas, which generated an internal bias field. This shifted the M-H hysteresis loops, yielding large values for the ME voltage coefficient of αME = 12 V/cm.Oe and 380 V/cm.Oe at 1 kHz and electromechanical resonance under zero magnetic bias, respectively. This self-biased laminate is shown to have a high sensitivity to ac magnetic fields.

  18. Social Anxiety and Interpretation Bias: Effect of Positive Priming.

    Science.gov (United States)

    Wang, Xiaoling; Qian, Mingyi; Yu, Hongyu; Sun, Yang; Li, Songwei; Yang, Peng; Lin, Muyu; Yao, Nishao; Zhang, Xilin

    2016-10-01

    This study examined how positive-scale assessment of ambiguous social stimuli affects interpretation bias in social anxiety. Participants with high and low social anxiety (N = 60) performed a facial expression discrimination task to assess interpretation bias. Participants were then randomly assigned to assess the emotion of briefly presented faces either on a negative or on a positive scale. They subsequently repeated the facial expression discrimination task. Participants with high versus low social anxiety made more negative interpretations of ambiguous facial expressions. However, those in the positive-scale assessment condition subsequently showed reduced negative interpretations of ambiguous facial expressions. These results suggest that interpretation bias in social anxiety could be mediated by positive priming rather than an outright negative bias.

  19. Impacts of SiN passivation on the degradation modes of AlGaN/GaN high electron mobility transistors under reverse-bias stress

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Wei-Wei; Ma, Xiao-Hua, E-mail: xhma@xidian.edu.cn, E-mail: yhao@xidian.edu.cn; Hou, Bin; Zhu, Jie-Jie [School of Advanced Materials and Nanotechnology, Xidian University, Xi' an 710071 (China); Key Laboratory of Wide Band-Gap Semiconductor Materials and Devices, School of Microelectronics, Xidian University, Xi' an 710071 (China); Chen, Yong-He; Zheng, Xue-Feng; Zhang, Jin-Cheng; Hao, Yue, E-mail: xhma@xidian.edu.cn, E-mail: yhao@xidian.edu.cn [Key Laboratory of Wide Band-Gap Semiconductor Materials and Devices, School of Microelectronics, Xidian University, Xi' an 710071 (China)

    2014-10-27

    Impacts of SiN passivation on the degradation modes of AlGaN/GaN high electron mobility transistors are investigated. The gate leakage current decreases significantly upon removing the SiN layer and no clear critical voltage for the sudden degradation of the gate leakage current can be observed in the reverse-bias step-stress experiments. Gate-lag measurements reveal the decrease of the fast-state surface traps and the increase of slow-state traps after the passivation layer removal. It is postulated that consistent surface charging relieves the electric field peak on the gate edge, thus the inverse piezoelectric effect is shielded.

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

    Science.gov (United States)

    Dennis, Tracy A.; O’Toole, Laura

    2015-01-01

    Interest in the use of mobile technology to deliver mental health services has grown in light of the economic and practical barriers to treatment. Yet, research on alternative delivery strategies that are more affordable, accessible, and engaging is in its infancy. Attention bias modification training (ABMT), has potential to reduce treatment barriers as a mobile intervention for stress and anxiety, but the degree to which ABMT can be embedded in a mobile gaming format and its potential for transfer of benefits is unknown. The present study examined effects of a gamified ABMT mobile application in highly trait anxious participants (N = 78). A single session of the active compared to placebo training reduced subjective anxiety and observed stress reactivity. Critically, the long (45 minutes) but not short (25 minutes) active training condition reduced the core cognitive process implicated in ABMT (threat bias) as measured by an untrained, gold-standard protocol. PMID:26029490

  1. Biaxial stress effects on magnetization perpendicular to the stress plane

    Energy Technology Data Exchange (ETDEWEB)

    Sablik, M.J.; Kwun, H.; Burkhardt, G.L. [Southwest Research Inst., San Antonio, TX (United States); Langman, R.A. [Univ. of Tasmania, Hobart, Tasmania (Australia)

    1995-11-01

    Effects of biaxial stress in steel on magnetization in a direction normal to the stress plane were investigated both theoretically and experimentally. The two results, which agreed qualitatively, showed that the magnetization in the normal direction generally decreased with the absolute value of the sum of the two principal stresses. The implication to nondestructive measurements of biaxial stress is discussed.

  2. Effective stress coefficient for uniaxial strain condition

    DEFF Research Database (Denmark)

    Alam, Mohammad Monzurul; Fabricius, Ida Lykke

    2012-01-01

    the reason for change in effective stress coefficient under stress. Our model suggests that change in effective stress coefficient will be higher at uniaxial stress condition than at hydrostatic condition. We derived equations from the original definition of Biot to estimate effective stress coefficient from...... one dimensional rock mechanical deformation. We further investigated the effect of boundary condition on the stress dependency of effective stress coefficient and discussed its application in reservoir study. As stress field in the reservoirs are most unlikely to be hydrostatic, effective stress...

  3. Training Production of Lexical Stress in Typically Developing Children Using Orthographically Biased Stimuli and Principles of Motor Learning

    Science.gov (United States)

    van Rees, Lauren J.; Ballard, Kirrie J.; McCabe, Patricia; Macdonald-D'Silva, Anita G.; Arciuli, Joanne

    2012-01-01

    Purpose: Impaired lexical stress production characterizes multiple pediatric speech disorders. Effective remediation strategies are not available, and little is known about the normal process of learning to assign and produce lexical stress. This study examined whether typically developing (TD) children can be trained to produce lexical stress on…

  4. Improving the accuracy of derivation of the Williams’ series parameters under mixed (I+II) mode loading by compensation of measurement bias in the stress field components data

    Science.gov (United States)

    Lychak, Oleh V.; Holyns'kiy, Ivan S.

    2016-12-01

    A new method for compensation of bias in the stress field components measurement data used for Williams’ series parameters derivation was presented. Essential increase of accuracy of derivation of SIF-related leading terms in series under mixed (I+II) mode loading was demonstrated. It was shown that a relatively low value of bias in the stress field components data error could result in the essential deviation of the values of derived Williams’ coefficients and the crack tip coordinates.

  5. Effects of GC bias in next-generation-sequencing data on de novo genome assembly.

    Science.gov (United States)

    Chen, Yen-Chun; Liu, Tsunglin; Yu, Chun-Hui; Chiang, Tzen-Yuh; Hwang, Chi-Chuan

    2013-01-01

    Next-generation-sequencing (NGS) has revolutionized the field of genome assembly because of its much higher data throughput and much lower cost compared with traditional Sanger sequencing. However, NGS poses new computational challenges to de novo genome assembly. Among the challenges, GC bias in NGS data is known to aggravate genome assembly. However, it is not clear to what extent GC bias affects genome assembly in general. In this work, we conduct a systematic analysis on the effects of GC bias on genome assembly. Our analyses reveal that GC bias only lowers assembly completeness when the degree of GC bias is above a threshold. At a strong GC bias, the assembly fragmentation due to GC bias can be explained by the low coverage of reads in the GC-poor or GC-rich regions of a genome. This effect is observed for all the assemblers under study. Increasing the total amount of NGS data thus rescues the assembly fragmentation because of GC bias. However, the amount of data needed for a full rescue depends on the distribution of GC contents. Both low and high coverage depths due to GC bias lower the accuracy of assembly. These pieces of information provide guidance toward a better de novo genome assembly in the presence of GC bias.

  6. Faraday Effect sensor redressed by Nd2Fe14B biasing magnetic film.

    Science.gov (United States)

    Jiao, Xinbing; Nguyen, Truong Giang; Qian, Bo; Jiang, Chunping; Ma, Lixin

    2012-01-16

    A Faraday Effect sensor with Nd(2)Fe(14)B biasing magnetic film was described. Ta/Nd(2)Fe(14)B/Ta films were grown by magnetron sputtering method. The magnetic domain in the sensor with the Nd(2)Fe(14)B biasing magnetic film can persist its distribution. The average linearity error of Faraday Effect sensor with biasing magnetic film decreased from 1.42% to 0.125% compared with non-biasing magnetic film, and the measurement range increased from 820 Oe to 900 Oe.

  7. Sex Stereotyping and Bias: Their Origin and Effects. Training Module IV.

    Science.gov (United States)

    Love, Reeve; Gonzales, Frank, Ed.

    The origin and effects of sex stereotyping and bias is the subject of this training module. It guides trainers through the activities and lessons necessary to aid education personnel in identifying sources and effects of sex stereotyping and bias in the classroom setting and in society as a whole. Seven activities are described and materials,…

  8. Sustainability of Teacher Expectation Bias Effects on Long-Term Student Performance

    Science.gov (United States)

    de Boer, Hester; Bosker, Roel J.; van der Werf, Margaretha P. C.

    2010-01-01

    In this article, we address the relationship between teacher expectation bias and student characteristics, its effect on long-term student performance, and the development of this effect over time. Expectation bias was defined as the difference between observed and predicted teacher expectation. These predicted expectations were estimated from a…

  9. Bias Corrections for Standardized Effect Size Estimates Used with Single-Subject Experimental Designs

    Science.gov (United States)

    Ugille, Maaike; Moeyaert, Mariola; Beretvas, S. Natasha; Ferron, John M.; Van den Noortgate, Wim

    2014-01-01

    A multilevel meta-analysis can combine the results of several single-subject experimental design studies. However, the estimated effects are biased if the effect sizes are standardized and the number of measurement occasions is small. In this study, the authors investigated 4 approaches to correct for this bias. First, the standardized effect…

  10. Sustainability of teacher expectation bias effects on long-term student performance

    NARCIS (Netherlands)

    de Boer, Hester; Bosker, R.J.; Van der Werf, M.P.C.

    2010-01-01

    In this article, we address the relationship between teacher expectation bias and student characteristics, its effect on long-term student performance, and the development of this effect over time. Expectation bias was defined as the difference between observed and predicted teacher expectation. The

  11. Investigating the effect of externalizing perspectives on cognitives biases

    DEFF Research Database (Denmark)

    Madsen, Fredrik Huitfeldt; Hicks, David L., David

    2007-01-01

    of intelligence analysis. We propose that complexity of maintaining multiple different perspectives the same data is one of the reasons for this. We further propose that a tool that facillitates the externalization multiple perspectives would reduce these biases and hence increase the overall quality...... the number of attacks that “get through”. There are many subproblems of this main problem, one of which is that relative quality of the intelligence analysis is too low [39, We observe that the analysts suffer from cognitive biases, and we assume that this is one of the reasons behind “low” quality...... of intelligence analyses....

  12. Improvement in the electrical performance and bias-stress stability of dual-active-layered silicon zinc oxide/zinc oxide thin-film transistor

    Science.gov (United States)

    Liu, Yu-Rong; Zhao, Gao-Wei; Lai, Pai-To; Yao, Ruo-He

    2016-08-01

    Si-doped zinc oxide (SZO) thin films are deposited by using a co-sputtering method, and used as the channel active layers of ZnO-based TFTs with single and dual active layer structures. The effects of silicon content on the optical transmittance of the SZO thin film and electrical properties of the SZO TFT are investigated. Moreover, the electrical performances and bias-stress stabilities of the single- and dual-active-layer TFTs are investigated and compared to reveal the effects of the Si doping and dual-active-layer structure. The average transmittances of all the SZO films are about 90% in the visible light region of 400 nm-800 nm, and the optical band gap of the SZO film gradually increases with increasing Si content. The Si-doping can effectively suppress the grain growth of ZnO, revealed by atomic force microscope analysis. Compared with that of the undoped ZnO TFT, the off-state current of the SZO TFT is reduced by more than two orders of magnitude and it is 1.5 × 10-12 A, and thus the on/off current ratio is increased by more than two orders of magnitude. In summary, the SZO/ZnO TFT with dual-active-layer structure exhibits a high on/off current ratio of 4.0 × 106 and superior stability under gate-bias and drain-bias stress. Projected supported by the National Natural Science Foundation of China (Grant Nos. 61076113 and 61274085), the Natural Science Foundation of Guangdong Province (Grant No. 2016A030313474), and the University Development Fund (Nanotechnology Research Institute, Grant No. 00600009) of the University of Hong Kong, China.

  13. Friendship Network in the Classroom: Parents Bias and Peer Effects

    DEFF Research Database (Denmark)

    Landini, Fabio; Montinari, Natalia; Pin, Paolo

    We interview both parents and their children enrolled in six primary schools in the district of Treviso (Italy). We study the structural differences between the children network of friends reported by children and the one elicited asking their parents. We find that the parents’ network has a bias...

  14. The Effect of Rater Training on Reducing Social Style Bias in Peer Evaluation

    Science.gov (United States)

    May, Gary L.

    2008-01-01

    This study employed a quasiexperimental control group design in a university setting to test the effect of a rater-training program on reducing social style bias in intragroup peer evaluations after controlling for ability based on GPA. Comparison of rating scores of the test group to the control group indicated minimal social style rating bias in…

  15. Tropical Atlantic biases and their relation to surface wind stress and terrestrial precipitation

    Energy Technology Data Exchange (ETDEWEB)

    Richter, Ingo [Research Institute for Global Change, JAMSTEC, Yokohama (Japan); University of Hawaii at Manoa, International Pacific Research Center, Honolulu, HI (United States); Xie, Shang-Ping [University of Hawaii at Manoa, International Pacific Research Center, Honolulu, HI (United States); University of Hawaii at Manoa, Department of Meteorology, Honolulu, HI (United States); Wittenberg, Andrew T. [NOAA/Geophysical Fluid Dynamics Laboratory, Princeton, NJ (United States); Masumoto, Yukio [Research Institute for Global Change, JAMSTEC, Yokohama (Japan)

    2012-03-15

    Most coupled general circulation models (GCMs) perform poorly in the tropical Atlantic in terms of climatological seasonal cycle and interannual variability. The reasons for this poor performance are investigated in a suite of sensitivity experiments with the Geophysical Fluid Dynamics Laboratory (GFDL) coupled GCM. The experiments show that a significant portion of the equatorial SST biases in the model is due to weaker than observed equatorial easterlies during boreal spring. Due to these weak easterlies, the tilt of the equatorial thermocline is reduced, with shoaling in the west and deepening in the east. The erroneously deep thermocline in the east prevents cold tongue formation in the following season despite vigorous upwelling, thus inhibiting the Bjerknes feedback. It is further shown that the surface wind errors are due, in part, to deficient precipitation over equatorial South America and excessive precipitation over equatorial Africa, which already exist in the uncoupled atmospheric GCM. Additional tests indicate that the precipitation biases are highly sensitive to land surface conditions such as albedo and soil moisture. This suggests that improving the representation of land surface processes in GCMs offers a way of improving their performance in the tropical Atlantic. The weaker than observed equatorial easterlies also contribute remotely, via equatorial and coastal Kelvin waves, to the severe warm SST biases along the southwest African coast. However, the strength of the subtropical anticyclone and along-shore winds also play an important role. (orig.)

  16. Transient plasma potential in pulsed dual frequency inductively coupled plasmas and effect of substrate biasing

    Science.gov (United States)

    Mishra, Anurag; Yeom, Geun Young

    2016-09-01

    An electron emitting probe in saturated floating potential mode has been used to investigate the temporal evolution of plasma potential and the effect of substrate RF biasing on it for pulsed dual frequency (2 MHz/13.56 MHz) inductively coupled plasma (ICP) source. The low frequency power (P2MHz) has been pulsed at 1 KHz and a duty ratio of 50%, while high frequency power (P13.56MHz) has been used in continuous mode. The substrate has been biased with a separate bias power at (P12.56MHz) Argon has been used as a discharge gas. During the ICP power pulsing, three distinct regions in a typical plasma potential profile, have been identified as `initial overshoot', pulse `on-phase' and pulse `off-phase'. It has been found out that the RF biasing of the substrate significantly modulates the temporal evolution of the plasma potential. During the initial overshoot, plasma potential decreases with increasing RF biasing of the substrate, however it increases with increasing substrate biasing for pulse `on-phase' and `off-phase'. An interesting structure in plasma potential profile has also been observed when the substrate bias is applied and its evolution depends upon the magnitude of bias power. The reason of the evolution of this structure may be the ambipolar diffusion of electron and its dependence on bias power.

  17. Citation bias and selective focus on positive findings in the literature on the serotonin transporter gene (5-HTTLPR), life stress and depression

    NARCIS (Netherlands)

    Vries, de Ymkje Anna; Roest, A. M.; Franzen, M.; Munaf, M. R.; Bastiaansen, J. A.

    2016-01-01

    Background Caspi et al.'s 2003 report that 5-HTTLPR genotype moderates the influence of life stress on depression has been highly influential but remains contentious. We examined whether the evidence base for the 5-HTTLPR-stress interaction has been distorted by citation bias and a selective focus o

  18. Measuring the effects of publication bias in political science

    Directory of Open Access Journals (Sweden)

    Justin Esarey

    2016-09-01

    Full Text Available Prior research finds that statistically significant results are overrepresented in scientific publications. If significant results are consistently favored in the review process, published results could systematically overstate the magnitude of their findings even under ideal conditions. In this paper, we measure the impact of this publication bias on political science using a new data set of published quantitative results. Although any measurement of publication bias depends on the prior distribution of empirical relationships, we determine that published estimates in political science are on average substantially larger than their true value under a variety of reasonable choices for this prior. We also find that many published estimates have a false positive probability substantially greater than the conventional α = 0.05 threshold for statistical significance if the prior probability of a null relationship exceeds 50%. Finally, although the proportion of published false positives would be reduced if significance tests used a smaller α, this change would not solve the problem of upward bias in the magnitude of published results.

  19. Acoustoelastic effect in stressed heterostructures.

    Science.gov (United States)

    Osetrov, Alexander Vladimirovich; Fröhlich, Heinz-Jürgen; Koch, Reinhold; Chilla, Eduard

    2002-01-01

    Mechanical stresses influence the phase velocity of acoustic waves, known as the AE (acoustoelastic) effect. In order to calculate the AE effect of biaxially stressed layered systems, we extended the transfer matrix method for acoustic wave propagation by considering the change of the density, the influence of residual stress, and the modification of the elastic stiffness tensor by residual strain and by third-order constants. The generalized method is applied to the calculation of the angular dispersion of the AE effect for transverse bulk modes and surface acoustic waves on Ge(001). Our calculations reveal that the AE effect significantly depends on the propagation direction and can even change sign. The maximal velocity change occurs for transversally polarized waves propagating parallel to the [110] direction. For the layered Ge/Si(001) system, the AE effect is investigated for Love modes propagating in the [100] and [110] directions. The AE effect increases rapidly with increasing layer thickness and almost reaches its maximal value when the wave still penetrates into the unstressed substrate.

  20. The effect of substrate bias on titanium carbide/amorphous carbon nanocomposite films deposited by filtered cathodic vacuum arc

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xu, E-mail: zhangxu@bnu.edu.cn [Key Laboratory of Beam Technology and Material Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University (China); Liang, Hong [Key Laboratory of Beam Technology and Material Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University (China); Wu, Zhenglong [Analytical and Testing Center, Beijing Normal University (China); Wu, Xiangying; Zhang, Huixing [Key Laboratory of Beam Technology and Material Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University (China)

    2013-07-15

    The titanium carbide/amorphous carbon nanocomposite films have been deposited on silicon substrate by filtered cathodic vacuum arc (FCVA) technology, the effects of substrate bias on composition, structures and mechanical properties of the films are studied by scanning electron spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy and nano-indentation. The results show that the Ti content, deposition rate and hardness at first increase and then decrease with increasing the substrate bias. Maximum hardness of the titanium carbide/amorphous carbon nanocomposite film is 51 Gpa prepared at −400 V. The hardness enhancement may be attributed to the compressive stress and the fraction of crystalline TiC phase due to ion bombardment.

  1. Biases in rhythmic sensorimotor coordination: effects of modality and intentionality.

    Science.gov (United States)

    Debats, Nienke B; Ridderikhoff, Arne; de Boer, Betteco J; Peper, C Lieke E

    2013-08-01

    Sensorimotor biases were examined for intentional (tracking task) and unintentional (distractor task) rhythmic coordination. The tracking task involved unimanual tracking of either an oscillating visual signal or the passive movements of the contralateral hand (proprioceptive signal). In both conditions the required coordination patterns (isodirectional and mirror-symmetric) were defined relative to the body midline and the hands were not visible. For proprioceptive tracking the two patterns did not differ in stability, whereas for visual tracking the isodirectional pattern was performed more stably than the mirror-symmetric pattern. However, when visual feedback about the unimanual hand movements was provided during visual tracking, the isodirectional pattern ceased to be dominant. Together these results indicated that the stability of the coordination patterns did not depend on the modality of the target signal per se, but on the combination of sensory signals that needed to be processed (unimodal vs. cross-modal). The distractor task entailed rhythmic unimanual movements during which a rhythmic visual or proprioceptive distractor signal had to be ignored. The observed biases were similar as for intentional coordination, suggesting that intentionality did not affect the underlying sensorimotor processes qualitatively. Intentional tracking was characterized by active sensory pursuit, through muscle activity in the passively moved arm (proprioceptive tracking task) and rhythmic eye movements (visual tracking task). Presumably this pursuit afforded predictive information serving the coordination process.

  2. Effects of electrode biasing in STOR-M Tokamak

    Science.gov (United States)

    Basu, Debjyoti; Nakajima, Masaru; Rohollahi, Akbar; McColl, David; Adegun, Joseph; Xiao, Chijin; Hirose, Akira

    2015-11-01

    STOR-M is an iron-core, limiter based tokamak with major and minor radii of 46cm and 12 cm, respectively. Recently, electrode biasing experiments have been carried to study the improved confinement. For this purpose we have developed a DC power supply which can be gated by a high power SCR. The rectangular SS electrode has a height of 10 cm, a width of 2 cm and a thickness of 0.2 cm. The radial position of the electrode throughout the experiments is kept around 4mm inside the limiter in the plasma edge region. After application of positive bias with voltages between +90 V to +110 V during the plasma discharge current flat top with slightly higher edge-qa (nearly 5 to 6), noticeable increment of average plasma density and soft x-ray intensity along the central chord have been observed. No distinguishable change in H α emission has been measured. These phenomena may be attributed to improved confinement formed at the inner region but not at the edge. In the upcoming experimental campaign, Ion Doppler spectroscopy will be used to measure possible velocity shear inside the inner plasma region. Edge plasma pressure gradient will also be measured using Langmuir probes. Detailed experimental results will be presented.

  3. Bias dependence of synergistic radiation effects induced by electrons and protons on silicon bipolar junction transistors

    Science.gov (United States)

    Liu, Chaoming; Li, Xingji; Yang, Jianqun; Ma, Guoliang; Xiao, Liyi

    2015-06-01

    Bias dependence on synergistic radiation effects caused by 110 keV electrons and 170 keV protons on the current gain of 3DG130 NPN bipolar junction transistors (BJTs) is studied in this paper. Experimental results indicate that the influence induced by 170 keV protons is always enhancement effect during the sequential irradiation. However, the influence induced by 110 keV electrons on the BJT under various bias cases is different during the sequential irradiation. The transition fluence of 110 keV electrons is dependent on the bias case on the emitter-base junction of BJT.

  4. Effects of temperature and electron effective mass on bias-dependent tunnelling magnetoresistance

    Institute of Scientific and Technical Information of China (English)

    Li Fei-Fei; Li Zheng-Zhong; Xiao Ming-Wen

    2005-01-01

    In this paper, we study the effects of temperature and electron effective mass within the barrier on the bias dependence and sign-change behaviour of the tunnelling magnetoresistance (TMR) in ferromagnetic junctions. A significant decrease of the tunnelling magnetoresistance with increasing temperature is obtained, in accordance with the experiments. In addition to the height of barrier potential (φ) discussed in our previous papers, the electron effective mass (mB) within the barrier region is found to be another important factor that physically controls the sign-change behaviour of the TMR. The critical voltage (Vc) at which TMR changes sign will increase with φ and decrease with mB. Furthermore, both the zero-bias TMR and Vc will decrease if the temperature rises. These results would be of practical use for experimental investigations.

  5. Impact of back-gate bias on the hysteresis effect in partially depleted SOI MOSFETs

    Institute of Scientific and Technical Information of China (English)

    Luo Jie-Xin; Chen Jing; Zhou Jian-Hua; Wu Qing-Qing; Chai Zhan; Yu Tao; Wang Xi

    2012-01-01

    The hysteresis effect in the output characteristics,originating from the floating body effect,has been measured in partially depleted(PD)silicon-on-insulator(SOl)MOSFETs at different back-gate biases.ID hysteresis has been developed to clarify the hysteresis characteristics.The fabricated devices show the positive and negative peaks in the ID hysteresis.The experimental results show that the ID hysteresis is sensitive to the back gate bias in 0.13μm PD SOI MOSFETs and does not vary monotonously with the back-gate bias.Based on the steady-state Shoclley-Read Hall(SRH)recombination theory,we have successfully interpreted the impact of the back-gate bias on the hysteresis effect in PD SOl MOSFETs.

  6. The Effectiveness of Cognitive Bias Modification Interventions for Substance Addictions: A Meta-Analysis

    DEFF Research Database (Denmark)

    Cristea, Ioana; Kok, Robin; Cuijpers, Pim

    2016-01-01

    were identified through systematic searches in bibliographical databases. We included RCTs of CBM interventions, alone or in combination with other treatments, for any type of addiction. We examined trial risk of bias, publication bias and possible moderators. Effects sizes were computed for post......Background and Aims Cognitive bias modification (CBM) interventions, presumably targeting automatic processes, are considered particularly promising for addictions. We conducted a meta-analysis examining randomized controlled trials (RCTs) of CBM for substance addiction outcomes. Methods Studies......-test and follow-up, using a random-effects model. We grouped outcome measures and reported results for addiction (all related measures), craving and cognitive bias. Results We identified 25 trials, 18 for alcohol problems, and 7 for smoking. At post-test, there was no significant effect of CBM for addiction, g...

  7. Posttraumatic Stress and Attentional Bias towards Cancer-Related Stimuli in Parents of Children Recently Diagnosed with Cancer.

    Directory of Open Access Journals (Sweden)

    Martin Cernvall

    Full Text Available To investigate whether posttraumatic stress symptoms (PTSS are related to attentional bias towards cancer-related stimuli among parents of children recently diagnosed with cancer.Sixty-two parents completed questionnaires measuring PTSS, depression, and anxiety and the emotional Stroop task via the Internet. The emotional Stroop task included cancer-related words, cardiovascular disease-related words, and neutral words.Participants were split in two groups based on the median of PTSS: High-PTSS and Low-PTSS. There was a significant interaction between word-type and group and a planned contrast test of this interaction indicated that the High-PTSS group had longer response latencies on cancer-related words compared to the other word-type and group combinations.Findings suggest that PTSS are related to attentional bias towards cancer-related stimuli among parents of children recently diagnosed with cancer. Implications of this finding for the understanding of PTSS in this population, future research, and clinical practice are discussed.

  8. Top-gate zinc tin oxide thin-film transistors with high bias and environmental stress stability

    Science.gov (United States)

    Fakhri, M.; Theisen, M.; Behrendt, A.; Görrn, P.; Riedl, T.

    2014-06-01

    Top gated metal-oxide thin-film transistors (TFTs) provide two benefits compared to their conventional bottom-gate counterparts: (i) The gate dielectric may concomitantly serve as encapsulation layer for the TFT channel. (ii) Damage of the dielectric due to high-energetic particles during channel deposition can be avoided. In our work, the top-gate dielectric is prepared by ozone based atomic layer deposition at low temperatures. For ultra-low gas permeation rates, we introduce nano-laminates of Al2O3/ZrO2 as dielectrics. The resulting TFTs show a superior environmental stability even at elevated temperatures. Their outstanding stability vs. bias stress is benchmarked against bottom-gate devices with encapsulation.

  9. Origin of degradation phenomenon under drain bias stress for oxide thin film transistors using IGZO and IGO channel layers.

    Science.gov (United States)

    Bak, Jun Yong; Kang, Youngho; Yang, Shinhyuk; Ryu, Ho-Jun; Hwang, Chi-Sun; Han, Seungwu; Yoon, Sung-Min

    2015-01-20

    Top-gate structured thin film transistors (TFTs) using In-Ga-Zn-O (IGZO) and In-Ga-O (IGO) channel compositions were investigated to reveal a feasible origin for degradation phenomenon under drain bias stress (DBS). DBS-driven instability in terms of V(TH) shift, deviation of the SS value, and increase in the on-state current were detected only for the IGZO-TFT, in contrast to the IGO-TFT, which did not demonstrate V(TH) shift. These behaviors were visually confirmed via nanoscale transmission electron microscopy and energy-dispersive x-ray spectroscopy observations. To understand the degradation mechanism, we performed ab initio molecular dynamic simulations on the liquid phases of IGZO and IGO. The diffusivities of Ga and In atoms were enhanced in IGZO, confirming the degradation mechanism to be increased atomic diffusion.

  10. The Effectiveness of Cognitive Bias Modification Interventions for Substance Addictions: A Meta-Analysis

    Science.gov (United States)

    Kok, Robin N.; Cuijpers, Pim

    2016-01-01

    Background and Aims Cognitive bias modification (CBM) interventions, presumably targeting automatic processes, are considered particularly promising for addictions. We conducted a meta-analysis examining randomized controlled trials (RCTs) of CBM for substance addiction outcomes. Methods Studies were identified through systematic searches in bibliographical databases. We included RCTs of CBM interventions, alone or in combination with other treatments, for any type of addiction. We examined trial risk of bias, publication bias and possible moderators. Effects sizes were computed for post-test and follow-up, using a random-effects model. We grouped outcome measures and reported results for addiction (all related measures), craving and cognitive bias. Results We identified 25 trials, 18 for alcohol problems, and 7 for smoking. At post-test, there was no significant effect of CBM for addiction, g = 0.08 (95% CI -0.02 to 0.18) or craving, g = 0.05 (95% CI -0.06 to 0.16), but there was a significant, moderate effect on cognitive bias, g = 0.60 (95% CI 0.39 to 0.79). Results were similar for alcohol and smoking outcomes taken separately. Follow-up addiction outcomes were reported in 7 trials, resulting in a small but significant effect of CBM, g = 0.18 (95% CI 0.03 to 0.32). Results for addiction and craving did not differ by substance type, sample type, delivery setting, bias targeted or number of sessions. Risk of bias was high or uncertain in most trials, for most criteria considered. Meta-regression analyses revealed significant inverse relationships between risk of bias and effect sizes for addiction outcomes and craving. The relationship between cognitive bias and respectively addiction ESs was not significant. There was consistent evidence of publication bias in the form of funnel plot asymmetry. Conclusions Our results cast serious doubts on the clinical utility of CBM interventions for addiction problems, but sounder methodological trials are necessary before

  11. Fear learning circuitry is biased toward generalization of fear associations in posttraumatic stress disorder

    OpenAIRE

    Morey, R.A.; Dunsmoor, J E; Haswell, C C; Brown, V M; Vora, A; Weiner, J.; Stjepanovic, D; Wagner, H R; ,; Brancu, Mira; Marx, Christine E.; Naylor, Jennifer C.; Van Voorhees, Elizabeth; Taber, Katherine H.; Beckham, Jean C.

    2015-01-01

    Fear conditioning is an established model for investigating posttraumatic stress disorder (PTSD). However, symptom triggers may vaguely resemble the initial traumatic event, differing on a variety of sensory and affective dimensions. We extended the fear-conditioning model to assess generalization of conditioned fear on fear processing neurocircuitry in PTSD. Military veterans (n=67) consisting of PTSD (n=32) and trauma-exposed comparison (n=35) groups underwent functional magnetic resonance ...

  12. Effect of residual stress on peak cap stress in arteries.

    Science.gov (United States)

    Vandiver, Rebecca

    2014-10-01

    Vulnerable plaques are a subset of atherosclerotic plaques that are prone to rupture when high stresses occur in the cap. The roles of residual stress, plaque morphology, and cap stiffness on the cap stress are not completely understood. Here, arteries are modeled within the framework of nonlinear elasticity as incompressible cylindrical structures that are residually stressed through differential growth. These structures are assumed to have a nonlinear, anisotropic, hyperelastic response to stresses in the media and adventitia layers and an isotropic response in the intima and necrotic layers. The effect of differential growth on the peak stress is explored in a simple, concentric geometry and it is shown that axial differential growth decreases the peak stress in the inner layer. Furthermore, morphological risk factors are explored. The peak stress in residually stressed cylinders is not greatly affected by changing the thickness of the intima. The thickness of the necrotic layer is shown to be the most important morphological feature that affects the peak stress in a residually stressed vessel.

  13. On a Class of Bias-Amplifying Variables that Endanger Effect Estimates

    CERN Document Server

    Pearl, Judea

    2012-01-01

    This note deals with a class of variables that, if conditioned on, tends to amplify confound- ing bias in the analysis of causal effects. This class, independently discovered by Bhat- tacharya and Vogt (2007) and Wooldridge (2009), includes instrumental variables and variables that have greater influence on treat- ment selection than on the outcome. We offer a simple derivation and an intuitive explana- tion of this phenomenon and then extend the analysis to non linear models. We show that: 1. the bias-amplifying potential of instru- mental variables extends over to non- linear models, though not as sweepingly as in linear models; 2. in non-linear models, conditioning on in- strumental variables may introduce new bias where none existed before; 3. in both linear and non-linear models, in- strumental variables have no effect on selection-induced bias.

  14. The impact of threat of shock on the framing effect and temporal discounting: executive functions unperturbed by acute stress?

    Directory of Open Access Journals (Sweden)

    Oliver Joe Robinson

    2015-08-01

    Full Text Available Anxiety and stress-related disorders constitute a large global health burden, but are still poorly understood. Prior work has demonstrated clear impacts of stress upon basic cognitive function: biasing attention towards unexpected and potentially threatening information and instantiating a negative affective bias. However, the impact that these changes have on higher-order, executive, decision-making processes is unclear. In this study we examined the impact of a translational within-subjects stress induction (threat of unpredictable shock on two well-established executive decision-making biases: the framing effect (N=83, and temporal discounting (N=36. In both studies, we demonstrate a clear subjective effects of stress, and b clear executive decision-making biases but c no impact of stress on these decision-making biases. Indeed, Bayes factor analyses confirmed substantial preference for decision-making models that did not include stress. We posit that while stress may induce subjective mood change and alter low-level perceptual and action processes (Robinson et al., 2013b, some higher-level executive processes remain unperturbed by these impacts. As such, although stress can induce a transient affective biases and altered mood, these need not result in poor financial decision-making.

  15. The impact of threat of shock on the framing effect and temporal discounting: executive functions unperturbed by acute stress?

    Science.gov (United States)

    Robinson, Oliver J; Bond, Rebecca L; Roiser, Jonathan P

    2015-01-01

    Anxiety and stress-related disorders constitute a large global health burden, but are still poorly understood. Prior work has demonstrated clear impacts of stress upon basic cognitive function: biasing attention toward unexpected and potentially threatening information and instantiating a negative affective bias. However, the impact that these changes have on higher-order, executive, decision-making processes is unclear. In this study, we examined the impact of a translational within-subjects stress induction (threat of unpredictable shock) on two well-established executive decision-making biases: the framing effect (N = 83), and temporal discounting (N = 36). In both studies, we demonstrate (a) clear subjective effects of stress, and (b) clear executive decision-making biases but (c) no impact of stress on these decision-making biases. Indeed, Bayes factor analyses confirmed substantial preference for decision-making models that did not include stress. We posit that while stress may induce subjective mood change and alter low-level perceptual and action processes (Robinson et al., 2013c), some higher-level executive processes remain unperturbed by these impacts. As such, although stress can induce a transient affective biases and altered mood, these need not result in poor financial decision-making.

  16. High-end climate change impact on European water availability and stress: exploring the presence of biases

    Directory of Open Access Journals (Sweden)

    L. V. Papadimitriou

    2015-07-01

    Full Text Available Climate models project a much more substantial warming than the 2 °C target making higher end scenarios increasingly plausible. Freshwater availability under such conditions is a key issue of concern. In this study, an ensemble of Euro-CORDEX projections under RCP8.5 is used to assess the mean and low hydrological states under +4 °C of global warming for the European region. Five major European catchments were analyzed in terms of future drought climatology and the impact of +2 vs. +4 °C global warming was investigated. The effect of bias correction of the climate model outputs and the observations used for this adjustment was also quantified. Projections indicate an intensification of the water cycle at higher levels of warming. Even for areas where the average state may not considerably be affected, low flows are expected to reduce leading to changes in the number of dry days and thus drought climatology. The identified increasing or decreasing runoff trends are substantially intensified when moving from the +2 to the +4 °C of global warming. Bias correction resulted in an improved representation of the historical hydrology. It is also found that the selection of the observational dataset for the application of the bias correction has an impact on the projected signal that could be of the same order of magnitude to the selection of the RCM.

  17. Alcohol-cue exposure effects on craving and attentional bias in underage college-student drinkers.

    Science.gov (United States)

    Ramirez, Jason J; Monti, Peter M; Colwill, Ruth M

    2015-06-01

    The effect of alcohol-cue exposure on eliciting craving has been well documented, and numerous theoretical models assert that craving is a clinically significant construct central to the motivation and maintenance of alcohol-seeking behavior. Furthermore, some theories propose a relationship between craving and attention, such that cue-induced increases in craving bias attention toward alcohol cues, which, in turn, perpetuates craving. This study examined the extent to which alcohol cues induce craving and bias attention toward alcohol cues among underage college-student drinkers. We designed within-subject cue-reactivity and visual-probe tasks to assess in vivo alcohol-cue exposure effects on craving and attentional bias on 39 undergraduate college drinkers (ages 18-20). Participants expressed greater subjective craving to drink alcohol following in vivo cue exposure to a commonly consumed beer compared with water exposure. Furthermore, following alcohol-cue exposure, participants exhibited greater attentional biases toward alcohol cues as measured by a visual-probe task. In addition to the cue-exposure effects on craving and attentional bias, within-subject differences in craving across sessions marginally predicted within-subject differences in attentional bias. Implications for both theory and practice are discussed. (PsycINFO Database Record

  18. Cognitive biases in processing infant emotion by women with depression, anxiety and post-traumatic stress disorder in pregnancy or after birth: A systematic review.

    Science.gov (United States)

    Webb, Rebecca; Ayers, Susan

    2015-01-01

    Perinatal psychological problems such as post-natal depression are associated with poor mother-baby interaction, but the reason for this is not clear. One explanation is that mothers with negative mood have biased processing of infant emotion. This review aimed to synthesise research on processing of infant emotion by pregnant or post-natal women with anxiety, depression or post-traumatic stress disorder (PTSD). Systematic searches were carried out on 11 electronic databases using terms related to negative affect, childbirth and perception of emotion. Fourteen studies were identified which looked at the effect of depression, anxiety and PTSD on interpretation of infant emotional expressions (k = 10), or reaction times when asked to ignore emotional expressions (k = 4). Results suggest mothers with depression and anxiety are more likely to identify negative emotions (i.e., sadness) and less accurate at identifying positive emotions (i.e., happiness) in infant faces. Additionally, women with depression may disengage faster from positive and negative infant emotional expressions. Very few studies examined PTSD (k = 2), but results suggest biases towards specific infant emotions may be influenced by characteristics of the traumatic event. The implications of this research for mother-infant interaction are explored.

  19. EFFECTIVE STRESS AND STRAIN IN FINITE DEFORMATION

    Institute of Scientific and Technical Information of China (English)

    周喆; 秦伶俐; 黄文彬; 王红卫

    2004-01-01

    Whether the concept of effective stress and strain in elastic-plastic theory is still valid under the condition of finite deformation was mainly discussed. The uni-axial compression experiments in plane stress and plane strain states were chosen for study. In the two kinds of stress states, the stress- strain curve described by logarithm strain and rotated Kirchhoff stress matches the experiments data better than the curves defined by other stressstrain description.

  20. EFFECTS OF ROCK BEHAVIOR AND STRESS CONDITIONON FIELD STRESS DETERMINATION

    Institute of Scientific and Technical Information of China (English)

    D.H.(Steve)Zou

    1995-01-01

    Non-consistency of stress results is often observed during field measurements. In some cases, even the measurements are made at the same location in a massive rockmass, the results can vary widely. In order to solve the problem, extensive research has been carried out to study the major factors which may affect stress determination. They include the rock behaviour and the stress state. For rocks showing non-isotropic behaviour, the values of Young's modulus and Poisson ratio vary with the orientation of loading and measurement. Stress condition in the rock affects the rock behaviour. Furthermore, the loading condition on rock samples during laboratory tests is different from in the field and therefore the determined elastic constants may not represent the field condition. In general, the Young's modulus may depend on the orientation, the loading path, the stress magnitude and the stress ratio. This paper examines in detail the effects of those factors, especially for rocks showing transversely isotropic behaviour. It is found that the discrepancy of stress results from fieldts in this type of rock is mainly due to over simplification of the rock behavior and inadequate use of elastic constants of the rock during stress calculation. A case study is given, which indicates the significance of these factors and demonstrates the proper procedure for stress calculation from

  1. A thermalization energy analysis of the threshold voltage shift in amorphous indium gallium zinc oxide thin film transistors under positive gate bias stress

    NARCIS (Netherlands)

    Niang, K.M.; Barquinha, P.M.C.; Martins, R.F.P.; Cobb, B.; Powell, M.J.; Flewitt, A.J.

    2016-01-01

    Thin film transistors (TFTs) employing an amorphous indium gallium zinc oxide (a-IGZO) channel layer exhibit a positive shift in the threshold voltage under the application of positive gate bias stress (PBS). The time and temperature dependence of the threshold voltage shift was measured and analyse

  2. The effects of self-focus on attentional biases in social anxiety:An ERP study.

    Science.gov (United States)

    Judah, Matt R; Grant, DeMond M; Carlisle, Nancy B

    2016-06-01

    Cognitive theories of social anxiety disorder suggest that biased attention plays a key role in maintaining symptoms. These biases include self-focus and attention to socially threatening stimuli in the environment. The goal of this study was to utilize ERPs that are elicited by a change detection task to examine biases in selective attention (i.e., N2pc) and working memory maintenance (i.e., contralateral delay activity; CDA). Additionally, the effect of self-focus was examined using false heart rate feedback. In support of the manipulation, self-focus cues resulted in greater self-reported self-consciousness and task interference, enhanced anterior P2 amplitude and reduced SPN amplitude. Moreover, P2 amplitude for self-focus cues was correlated with reduced task performance for socially anxious subjects only. The difference in P2 amplitude between self-focus and standard cues was correlated with social anxiety independent of depression. As hypothesized, socially anxious participants (n = 20) showed early selection and maintenance of disgust faces relative to neutral faces as indicated by the N2pc and CDA components. Nonanxious controls (n = 22) did not show these biases. During self-focus cues, controls showed marginal evidence of biased selection for disgust faces, whereas socially anxious subjects showed no bias in this condition. Controls showed an ipsilateral delay activity after being cued to attend to one hemifield. Overall, this study supports early and persistent attentional bias for social threat in socially anxious individuals. Furthermore, self-focus may disrupt these biases. These findings and supplementary data are discussed in light of cognitive models of social anxiety disorder, recent empirical findings, and treatment.

  3. Exchange bias effect modified asymmetric magnetization reversal in Ni/YMnO3 multiferroic bilayers

    Science.gov (United States)

    Gong, Junlu; Zheng, Dongxing; Li, Dong; Jin, Chao; Li, Peng; Feng, Liefeng; Bai, Haili

    2016-04-01

    Exchange bias (EB) effect modified asymmetric magnetization reversal in Ni/YMnO3 multiferroic bilayers was investigated by combining anisotropic magnetoresistance (AMR) with free energy methods. The promotion and inhibition effects of EB field on magnetization rotation result in the asymmetry of magnetization reversal. The AMR curves exhibit shape transition from arc-like to sin2θH-dependence with increasing external fields due to the competition between Zeeman energy and interfacial coupling energy. The phase shift and asymmetric behaviors become weak as the EB field decreases. Our work suggests that controlling the EB effect can be an alternative way to manipulate the magnetization reversal in exchange biased systems.

  4. Finale furioso: referee-biased injury times and their effects on home advantage in football.

    Science.gov (United States)

    Riedl, Dennis; Strauss, Bernd; Heuer, Andreas; Rubner, Oliver

    2015-01-01

    The role of referees has become a central issue in the investigation of home advantage. The main aim of this study was a thorough examination of the referee bias concerning injury time in football, which is currently seen as an important example for the assertion that referees contribute to home advantage. First, we use archival data from the German Bundesliga (seasons 2000/2001-2010/2011) to confirm the existence of an asymmetry in the allocation of injury time. We show this asymmetry to be a bias by ruling out hitherto remaining alternative explanations (effect = 18 s, P team leads in the game compared to a draw (effect = 21 s, P = 0.004, R2(adj) = 0.06). Third, the quantitative benefit of home or away teams in goals and points due to these biases is assessed. Overall, referee decisions on injury time indeed reveal biases, but they do not contribute to the home advantage, that is, there is no significant effect on goals scored by the teams. The qualitative findings (a new bias on injury time) as well as the quantitative findings (no overall effect) shed new light on the role of referees for home advantage.

  5. A stress "deafness" effect in European Portuguese.

    Science.gov (United States)

    Correia, Susana; Butler, Joseph; Vigário, Marina; Frota, Sónia

    2015-03-01

    Research on the perception of word stress suggests that speakers of languages with non-predictable or variable stress (e.g., English and Spanish) are more efficient than speakers of languages with fixed stress (e.g., French and Finnish) at distinguishing nonsense words contrasting in stress location. In addition, segmental and suprasegmental cues to word stress may also impact on the ability of speakers to perceive stress. European Portuguese (EP) is a language with variable stress and vowel reduction. Previous studies on EP have identified duration as the main cue for stress. In the present study, we investigated the perception of word stress in EP, both in nuclear (NP) and post-nuclear (PN) positions, by means of three experiments. Experiment I was an ABX discrimination task with stress and phoneme contrasts, without vowel reduction. Experiments 2 and 3 were sequence recall tasks with stress and phoneme contrasts, vowel reduction being added to the stress contrast only in experiment 3. Results showed significantly higher error rates in the stress contrast condition than in the phoneme contrast condition, when duration alone (PN), or duration and pitch accents (NP), are present in the stimuli (experiments I and 2). When vowel reduction is added, EP speakers are able to perceive stress contrasts (experiment 3). The results show that vowel reduction appears to be the most robust cue for stress in EP. In the absence of vowel quality cues, a stress "deafness" effect may emerge in a language with non-predictable stress that combines both suprasegmental and segmental information to signal word stress. These findings have implications for claims of a prosodic-based cross-linguistic perception of word stress in the absence of vowel quality, and for stress "deafness" as a consequence of a predictable stress grammar.

  6. Impact of substrate bias on radiation-inducededge effects in MOSFETs

    Institute of Scientific and Technical Information of China (English)

    Hu Zhi-Yuan; Liu Zhang-Li; Shao-Hua; Zhang Zheng-Xuan; Ning Bing-Xu; Chen Ming; Bi Da-Wei; Zou Shi-Chang

    2011-01-01

    This paper investigates the effects of gamma-ray irradiiation on the Shallow-Trench Isolation (STI) leakage currents in 180-nm complementary metal oxide semiconductor technology.No hump effect in the subthreshold region is observed after irradiation,which is considered to be due to the thin STI corner oxide thickness.A negative substrate bias could effectively suppress the STI leakage,but it also impairs the device characteristics.The three-dimensional simulation is introduced to understand the impact of substrate bias.Moreover,we propose a simple method for extracting the best substrate bias value,which not only eliminates the STI leakage but also has the least impact on the device characteristics.

  7. Effect of external and internal magnetic fields on the bias stability in a Zeeman laser gyroscope

    Energy Technology Data Exchange (ETDEWEB)

    Kolbas, Yu Yu; Saveliev, I I; Khokhlov, N I [Open Joint-Stock Company M.F. Stel' makh Polyus Research Institute, Moscow (Russian Federation)

    2015-06-30

    With the specific features of electronic systems of a Zeeman laser gyroscope taken into account, the basic physical mechanisms of the magnetic field effect on the bias stability and the factors giving rise to the internal magnetic fields are revealed. The hardware-based methods of reducing the effect of external and internal magnetic fields are considered, as well as the algorithmic methods for increasing the stability of the bias magnetic component by taking into account its reproducible temperature and time dependences. Typical experimental temperature and time dependences of the magnetic component of the Zeeman laser gyro bias are presented, and by their example the efficiency of the proposed methods for reducing the effect of magnetic fields is shown. (laser gyroscopes)

  8. Relative Age Effect in Elite Sports: Methodological Bias or Real Discrimination?

    CERN Document Server

    Delorme, Nicolas; Raspaud, Michel; 10.1080/17461390903271584

    2010-01-01

    Sport sciences researchers talk about a relative age effect when they observe a biased distribution of elite athletes' birthdates, with an over-representation of those born at the beginning of the competitive year and an under-representation of those born at the end. Using the whole sample of the French male licensed soccer players (n = 1,831,524), our study suggests that there could be an important bias in the statistical test of this effect. This bias could in turn lead to falsely conclude to a systemic discrimination in the recruitment of professional players. Our findings question the accuracy of past results concerning the existence of this effect at the elite level.

  9. Exchange bias effect in spin glass CoCr{sub 2}O{sub 4} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Changming; Tian, Zhaoming; Wang, Liguang; Yuan, Songliu, E-mail: yuansl@hust.edu.cn

    2015-11-01

    CoCr{sub 2}O{sub 4} nanoparticles are about 5.4 nm in diameter synthesized by a hydrothermal technique. Magnetization measurements reveal that the nanoparticles exhibit a spin glass behavior below glass transition temperature. Signature of memory effect is clear in reheating curve where the step-like shape increasing with the increase of temperature is recovered after cooling process. Magnetic relaxation is performed to prove memory effect. Ageing effect is also detected in CoCr{sub 2}O{sub 4} nanoparticles to verify the spin glass behavior. As temperature decreases to 5 K, which is far below the glass transition temperature, exchange bias effect can be observed clearly accompanied with a shift in field-cooled hysteresis loop. As particle size decreases to 5.4 nm, spin glass behavior appears due to the increased spin disorder effect. The spin glass phase providing a pinning force from some frozen spins to the rotatable spins gives the key to explain the exchange bias effects. - Highlights: • Existence of spin glass phase is verified in CoCr{sub 2}O{sub 4} nanoparticles. • Exchange bias effect with a shift in field-cooled loop is observed at 5 K. • It is proved that exchange bias effect is originated from the spin glass phase.

  10. Do Methodological Choices in Environmental Modeling Bias Rebound Effects? : A Case Study on Electric Cars

    NARCIS (Netherlands)

    Font Vivanco, D.; Tukker, A.; Kemp, R.

    2016-01-01

    Improvements in resource efficiency often underperform because of rebound effects. Calculations of the size of rebound effects are subject to various types of bias, among which methodological choices have received particular attention. Modellers have primarily focused on choices related to changes i

  11. Photocurrent Effect in Reverse-Biased p-n Silicon Waveguides in Communication Bands

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yong; XU Chao; WANG Wan-Jun; ZHOU Qiang; HAO Yin-Lei; YANG Jian-Yi; WANG Ming-Hua; JIANG Xiao-Qing

    2011-01-01

    The photocurrent effect in reverse biased p-n silicon waveguides at wavelength 1550nm is experimentally investigated.The photocurrent,which is mainly related to surface-state absorption,defect-state absorption and/or two-photon absorption,is more than 0.08 μA/mm under 8 V reverse biasing and 0.75 mW irradiation.The responsivity of a silicon waveguide with length of 4500 μm achieves 0.S mA/W.Moreover,the enhancement of the photocurrent effect under the electric field is discussed.

  12. On/off switching of bit readout in bias-enhanced tunnel magneto-Seebeck effect

    Science.gov (United States)

    Boehnke, Alexander; Milnikel, Marius; von der Ehe, Marvin; Franz, Christian; Zbarsky, Vladyslav; Czerner, Michael; Rott, Karsten; Thomas, Andy; Heiliger, Christian; Reiss, Günter; Münzenberg, Markus

    2015-03-01

    Thermoelectric effects in magnetic tunnel junctions are promising to serve as the basis for logic devices or memories in a ''green'' information technology. However, up to now the readout contrast achieved with Seebeck effects was magnitudes smaller compared to the well-established tunnel magnetoresistance effect. Here, we resolve this problem by demonstrating that the tunnel magneto-Seebeck effect (TMS) in CoFeB/MgO/CoFeB tunnel junctions can be switched on to a logic ``1'' state and off to ``0'' by simply changing the magnetic state of the CoFeB electrodes. This new functionality is achieved by combining a thermal gradient and an electric field. Our results show that the signal crosses zero and can be adjusted by tuning a bias voltage that is applied between the electrodes of the junction; hence, the name of the effect is bias-enhanced tunnel magneto-Seebeck effect (bTMS). Via the spin- and energy-dependent transmission of electrons in the junction, the bTMS effect can be configured using the bias voltage with much higher control than the tunnel magnetoresistance and even completely suppressed for only one magnetic configuration. Moreover, our measurements are a step towards the experimental realization of high TMS ratios without additional bias voltage, which are predicted for specific Co-Fe compositions.

  13. Stress Effects on Multiple Memory System Interactions

    Directory of Open Access Journals (Sweden)

    Deborah Ness

    2016-01-01

    Full Text Available Extensive behavioural, pharmacological, and neurological research reports stress effects on mammalian memory processes. While stress effects on memory quantity have been known for decades, the influence of stress on multiple memory systems and their distinct contributions to the learning process have only recently been described. In this paper, after summarizing the fundamental biological aspects of stress/emotional arousal and recapitulating functionally and anatomically distinct memory systems, we review recent animal and human studies exploring the effects of stress on multiple memory systems. Apart from discussing the interaction between distinct memory systems in stressful situations, we will also outline the fundamental role of the amygdala in mediating such stress effects. Additionally, based on the methods applied in the herein discussed studies, we will discuss how memory translates into behaviour.

  14. Effect of biasing on plasma rotation in the edge of IR-T1 Tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Mohammadi, S.; Ghoranneviss, M.; Arvin, R.; Gheydi, M.; Nikmohammadi, A. [Plasma physics Research Center, Science and Research Branch, Islamic Azad University, P.O.Box: 14665-768 Tehran (Iran, Islamic Republic of); Khorshid, P.; Bolourian, H. [Department of Physics, Islamic Azad University, Mashhad Branch, Mashhad (Iran, Islamic Republic of)

    2011-07-01

    Full text of publication follows: Electrode biasing experiments were carried out on the IR-T1 Tokamak. The effects of radial electric field (Er) on plasma fluid velocity and magnetic island rotation investigated by a Mach/Langmuir electric probe and an array of 12 Mirnov coils. The Results have shown a change in the fluid velocity during biasing regime. References: [1] Van Oost G. et al. 2001 Czech. J. of Phys. 51 957; [2] Effect of Plasma Biasing on Suppression of Electrostatic Fluctuation in the Edge Region of STP-3(M) Reversed Field Pinch J. Phys. Soc. Jpn. 74 (2005) pp.605-612; [3] Weynants R. R. and Van Oost G. 1993 Plasma Phys. Contr. Fusion 35 B177. (authors)

  15. Fluency and belief bias in deductive reasoning: New indices for old effects

    Directory of Open Access Journals (Sweden)

    Dries eTrippas

    2014-06-01

    Full Text Available Models based on signal detection theory (SDT have occupied a prominent role in domains such as perception, categorisation, and memory. Recent work by Dube et al. (2010 suggests that the framework may also offer important insights in the domain of deductive reasoning. Belief bias in reasoning has traditionally been examined using indices based on raw endorsement rates – indices that critics have claimed are highly problematic. We discuss a new set of SDT indices fit for the investigation belief bias and apply them to new data examining the effect of perceptual disfluency on belief bias in syllogisms. In contrast to the traditional approach, the SDT indices do not violate important statistical assumptions, resulting in a decreased Type 1 error rate. Based on analyses using these novel indices we demonstrate that disfluency leads to decreased reasoning accuracy, contrary to predictions. Disfluency also appears to eliminate the typical link found between cognitive ability and the effect of beliefs on accuracy. Finally, replicating previous work, we demonstrate that cognitive ability leads to an increase in reasoning accuracy and a decrease in the response bias component of belief bias.

  16. The effect of cognitive bias modification for interpretation on avoidance of pain during an acute experimental pain task.

    Science.gov (United States)

    Jones, Emma Blaisdale; Sharpe, Louise

    2014-08-01

    Research confirms that patients with chronic pain show a tendency to interpret ambiguous stimuli as pain related. However, whether modifying these interpretive pain biases impacts pain outcomes is unknown. This study aimed to demonstrate that interpretation biases towards pain can be modified, and that changing these biases influences pain outcomes in the cold pressor task. One hundred and six undergraduate students were randomly allocated to receive either threatening or reassuring information regarding the cold pressor. They also were randomly allocated to 1 of 2 conditions in the Ambiguous Scenarios Task, in which they were trained to have either a threatening interpretation of pain (pain bias condition) or a nonthreatening interpretation of pain (no pain bias condition). Therefore, the study had a 2 (threat/reassuring)×2 (pain bias/no pain bias) design. Analyses showed that a bias was induced contingent on condition, and that the threat manipulation was effective. Participants in the pain bias condition hesitated more before doing the cold pressor task than those in the no pain bias condition, as did those in the threat compared with the reassurance condition. The major finding was that interpretive bias mediated the relationship between bias condition and hesitance time, supporting the causal role of interpretive biases for avoidance behaviors in current chronic pain models. No differences were found on other pain outcomes regarding bias or threat, and the efficacy of the bias modification was not impacted by different levels of threat. These results suggest that cognitive bias modification should be further explored as a potential intervention in pain.

  17. Galaxy bias and its effects on the Baryon acoustic oscillations measurements

    Energy Technology Data Exchange (ETDEWEB)

    Mehta, Kushal T. [Univ. of Arizona, Tucson, AZ (United States); Seo, Hee -Jong [Univ. of California, Berkeley, CA (United States); Fermi National Accelerator Lab., Batavia, IL (United States); Eckel, Jonathan [Univ. of Arizona, Tucson, AZ (United States); Eisenstein, Daniel J. [Univ. of Arizona, Tucson, AZ (United States); Harvard Univ., Cambridge, MA (United States); Metchnik, Marc [Univ. of Arizona, Tucson, AZ (United States); Pinto, Philip [Univ. of Arizona, Tucson, AZ (United States); Xu, Xiaoying [Univ. of Arizona, Tucson, AZ (United States)

    2011-05-31

    The baryon acoustic oscillation (BAO) feature in the clustering of matter in the universe serves as a robust standard ruler and hence can be used to map the expansion history of the universe. We use high force resolution simulations to analyze the effects of galaxy bias on the measurements of the BAO signal. We apply a variety of Halo Occupation Distributions (HODs) and produce biased mass tracers to mimic different galaxy populations. We investigate whether galaxy bias changes the non-linear shifts on the acoustic scale relative to the underlying dark matter distribution presented by Seo et al. (2009). For the less biased HOD models (b < 3), we do not detect any shift in the acoustic scale relative to the no-bias case, typically 0.10% ± 0.10%. However, the most biased HOD models (b > 3) show a shift at moderate significance (0.79% ± 0.31% for the most extreme case). We test the one-step reconstruction technique introduced by Eisenstein et al. (2007) in the case of realistic galaxy bias and shot noise. The reconstruction scheme increases the correlation between the initial and final (z = 1) density fields achieving an equivalent level of correlation at nearly twice the wavenumber after reconstruction. Reconstruction reduces the shifts and errors on the shifts. We find that after reconstruction the shifts from the galaxy cases and the dark matter case are consistent with each other and with no shift. The 1σ systematic errors on the distance measurements inferred from our BAO measurements with various HODs after reconstruction are about 0.07%-0.15%.

  18. Exchange biasing with multiferroic: electric field effects on magnetic and magnetotransport properties

    Science.gov (United States)

    Fontcuberta, J.

    2008-03-01

    Room-temperature multiferroic materials are scarce and display a weak magnetoelectric coupling and thus huge difficulties exist for controlling the magnetic state by using an electric field or viceversa. A possible alternative to circumvent this limitation is to exploit the clamping of ferroelectric and antiferromagnetic domains in biferroic materials and use a suitable exchange-bias existing with ferromagnetic materials to tune the magnetic response of the ferromagnet. In this presentation we shall overview recent experiments on exchange-biasing using hexagonal YMnO3 biferroics and Permalloy as a soft-ferromagnet. Exchange-bias on ferromagnetic materials is most commonly evidenced by their magnetic response, although magnetotransport measurements are also very adequate to monitor the exchange bias. We will present and discus first how exchange-bias is manifested and monitored. Next, we will describe the effects of an electric field, biasing the ferroelectric (and antiferromagnetic) epitaxial layer, on the exchange bias. We will show that under appropriate conditions, magnetization can be switched by application of a suitable electric field. We will discuss the significance of the results with particular attention to role of current leakages across the ferroelectric. In collaboration with X. Mart'i, Institut de Ciència de Materials de Barcelona-CSIC, Spain; V. Laukhin, Institut de Ciència de Materials de Barcelona-CSIC and Institut Catalàde Recerca i Estudis Avancats (ICREA), Barcelona, Catalonia, Spain; V. Skumryev, Institut Catalàde Recerca i Estudis Avancats (ICREA) and Departament de F'isica, Universitat Autònoma de Barcelona, Spain; D. Hrabovsky and F. S'anchez, Institut de Ciència de Materials de Barcelona-CSIC, Spain; M. Varela, Departament de F'isica Aplicada i Òptica, Universitat de Barcelona, Spain; U. Lüders and J.F. Bobo, LNMH ONERA-CNRS, France.

  19. Selection bias in evaluating of influenza vaccine effectiveness: a lesson from an observational study of elderly nursing home residents.

    Science.gov (United States)

    Fukushima, Wakaba; Hayashi, Yoshimitsu; Mizuno, Yaichi; Suzuki, Kanzo; Kase, Tetsuo; Ohfuji, Satoko; Fujieda, Megumi; Maeda, Akiko; Hirota, Yoshio

    2008-11-25

    Selection bias is of critical concern in the study of influenza vaccine effectiveness when using an observational study design. This bias is attributable to the inherently different characteristics between vaccinees and non-vaccinees. The differences, which are related both to vaccination and signs of clinical disease as an outcome, may lead to erroneous estimation of the effectiveness. In this report, we describe how selection bias among elderly nursing home residents may lead to a spurious interpretation of the protective effect of influenza vaccine. Our results should be a lesson in the importance of regarding selection bias when assessing influenza vaccine effectiveness.

  20. Effect of precipitation bias correction on water budget calculation in Upper Yellow River, China

    Science.gov (United States)

    Ye, Baisheng; Yang, Daqing; Ma, Lijuan

    2012-06-01

    This study quantifies the effect of precipitation bias corrections on basin water balance calculations for the Yellow River Source region (YRS). We analyse long-term (1959-2001) monthly and yearly data of precipitation, runoff, and ERA-40 water budget variables and define a water balance regime. Basin precipitation, evapotranspiration and runoff are high in summer and low in winter. The basin water storage change is positive in summer and negative in winter. Monthly precipitation bias corrections, ranging from 2 to 16 mm, do not significantly alter the pattern of the seasonal water budget. The annual bias correction of precipitation is about 98 mm (19%); this increase leads to the same amount of evapotranspiration increase, since yearly runoff remains unchanged and the long-term storage change is assumed to be zero. Annual runoff and evapotranspiration coefficients change, due to precipitation bias corrections, from 0.33 and 0.67 to 0.28 and 0.72, respectively. These changes will impact the parameterization and calibration of land surface and hydrological models. The bias corrections of precipitation data also improve the relationship between annual precipitation and runoff.

  1. Galaxy Bias and its Effects on the Baryon Acoustic Oscillations Measurements

    CERN Document Server

    Mehta, Kushal T; Eckel, Jonathan; Eisenstein, Daniel J; Metchnik, Marc; Pinto, Philip; Xu, Xiaoying

    2011-01-01

    The baryon acoustic oscillation (BAO) feature in the clustering of matter in the universe serves as a robust standard ruler and hence can be used to map the expansion history of the universe. We use high force resolution simulations to analyze the effects of galaxy bias on the measurements of the BAO signal. We apply a variety of Halo Occupation Distributions (HODs) and produce biased mass tracers to mimic different galaxy populations. We investigate whether galaxy bias changes the non-linear shifts on the acoustic scale relative to the underlying dark matter distribution presented by Seo et al (2009). For the less biased HOD models (b 3) show a shift at moderate significance (0.79% \\pm 0.31% for the most extreme case). We test the one-step reconstruction technique introduced by Eisenstein et al. (2007) in the case of realistic galaxy bias and shot noise. The reconstruction scheme increases the correlation between the initial and final (z = 1) density fields achieving an equivalent level of correlation at ne...

  2. Effect of Barrier Width on Bias-Dependent Tunnelling in Ferromagnetic Junctions

    Institute of Scientific and Technical Information of China (English)

    LI Fei-Fei; XIAO Ming-Wen; LI Zheng-Zhong; HU An; XU Wang

    2004-01-01

    @@ We present a finite temperature theory for bias-dependent tunnelling in ferromagnetic tunnelling junctions. The effects of the barrier width d on the tunnelling magnetoresistance (TMR) and its sign change behaviour are discussed with this theory. Numerical results show that both the zero-bias TMR and the critical voltage Vc at which the TMR changes its sign decrease with the increasing barrier width for a considerably thick barrier junction. Furthermore, it is found that a minimum exists in the curve of Vc versus d if a composite junction is under oxidized.

  3. Exchange bias effect in Ti doped nanocrystalline SrFeO3-δ

    Directory of Open Access Journals (Sweden)

    A. Sendil Kumar

    2014-08-01

    Full Text Available Materials of Ti doped nanocrystalline SrFeO3-δ were synthesized through solid state reaction. Detailed magnetization measurements were carried out in zero field cooled (ZFC and field cooled (FC conditions. Compounds of SrFe1-xTixO3-δ (x = 0.1 to 0.3 are found to be spin glass and parent compound is a helical antiferromagnet. Non magnetic Ti4+ reduces the strength of exchange interactions and the curvature of hysteresis is changed towards concave nature. Exchange bias is observed below the peak temperature (irreversibility in magnetization (TIrr in ZFC-FC of SrFe1-xTixO3-δ (x = 0 to 0.3. The coercivity and exchange bias field values are found to be decreases with increase in temperature. Observed exchange bias effect is attributed to competition between antiferromagnetic superexchange and ferromagnetic double exchange interactions.

  4. Effect of a Biased Probe on the Afterglow Operation of an ECR4 Ion Source

    CERN Document Server

    Hill, C E; Wenander, F; Wolf, B H

    2000-01-01

    Various experiments have been performed on a 14.5 GHz ECR4 in order to improve the ion yield. The source runs in pulsed afterglow mode, and provides currents ~120 emA of Pb27+ to the CERN Heavy Ion Facility on an operational basis. In the search for higher beam intensities, the effects of a pulsed biased disk on axis at the injection side were investigated with different pulse timing and voltage settings. No proof for absolute higher intensities was seen for any of these modifications. However, the yield from a poorly tuned/low-performing source could be improved and the extracted pulse was less noisy with bias voltage applied. The fast response on the bias implies that increases/decreases are not due to ionisation processes. A good tune for high yield of high charge states during the afterglow coincides with a high plasma potential.

  5. Effect of DC bias on electrical conductivity of nanocrystalline α-CuSCN

    Directory of Open Access Journals (Sweden)

    T. Prakash

    2011-06-01

    Full Text Available The grain boundary space charge depletion layer in nanocrystalline alpha phase CuSCN is investigated by studying electrical properties using impedance spectroscopic analysis in frequency domain. The measurements were performed at room temperature in wide frequency range 1 Hz to 1 MHz under various DC bias applied voltages ranges from 0 V to -2.1 V. The effect of bias on grain and grain boundary contribution electrical conductivity has been investigated by equivalent circuit model using non-linear least squares (NLLS fitting of the impedance data. Three order of magnitude variation of grain boundary conductivity was observed for varying 0 V to -2.1 V. Variations in the σac clearly elucidate the DC bias is playing crucial role on grain boundary double Schottky barriers of nanocrystalline α-CuSCN.

  6. The effects of assembly bias on cosmological inference from galaxy-galaxy lensing and galaxy clusters

    CERN Document Server

    McEwen, Joseph E

    2016-01-01

    The combination of galaxy-galaxy lensing (GGL) and galaxy clustering is a promising route to measuring the amplitude of matter clustering and testing modified gravity theories of cosmic acceleration. Halo occupation distribution (HOD) modeling can extend the approach down to nonlinear scales, but galaxy assembly bias could introduce systematic errors by causing the HOD to vary with large scale environment at fixed halo mass. We investigate this problem using the mock galaxy catalogs created by Hearin & Watson (2013, HW13), which exhibit significant assembly bias because galaxy luminosity is tied to halo peak circular velocity and galaxy colour is tied to halo formation time. The preferential placement of galaxies (especially red galaxies) in older halos affects the cutoff of the mean occupation function $\\langle N_\\text{cen}(M_\\text{min}) \\rangle$ for central galaxies, with halos in overdense regions more likely to host galaxies. The effect of assembly bias on the satellite galaxy HOD is minimal. We intro...

  7. Effect of particle size on the exchange bias of Fe-doped CuO nanoparticles

    Science.gov (United States)

    Yin, S. Y.; Yuan, S. L.; Tian, Z. M.; Liu, L.; Wang, C. H.; Zheng, X. F.; Duan, H. N.; Huo, S. X.

    2010-02-01

    Effect of particle size on exchange bias in Fe-doped CuO nanoparticles is investigated, which are sintered at different temperatures from 350 to 650 °C, respectively. The structure and magnetic properties for different particle size samples were probed. It is found that the system shows magnetic properties transition from paramagnetic to ferromagnetic with increasing grain size, and exhibits the variations in exchange bias field (HEB) and coercivity (HC) at low temperature after field-cooled from 300 K. With the increase in the particles size, HEB decreases monotonously. Furthermore, vertical magnetization shift was also observed for the small particles. Exchange bias is attributed to the exchange coupling interactions between ferromagnetic and spin-glass-like (or antiferromagnetic) phase interface layers.

  8. Effects of DC bias voltages on the RF-excited plasma-tissue interaction

    Science.gov (United States)

    Yang, Aijun; Liu, Dingxin; Wang, Xiaohua; Li, Jiafeng; Chen, Chen; Rong, Mingzhe; Kong, Michael G.

    2016-10-01

    We present in this study how DC bias voltage impacts on the fluxes of reactive species on the skin tissue by means of a plasma-tissue interaction model. The DC bias voltage inputs less than 2% of the total discharge power, and hence it has little influence on the whole plasma characteritics including the volume-averaged densities of reactive species and the heating effect. However, it pushes the plasma bulk towards the skin surface, which significantly changes the local plasma characteristics in the vicinity of the skin surface, and in consequence remarkably enhances the flux densities of reactive species on the skin tissue. With the consideration of plasma dosage and heat damage on the skin tissue, DC bias voltage is a better approach compared with the common approach of increasing the plasma power. Since the DC voltage is easy to apply on the human body, it is a promising approach for use in clincial applications.

  9. Bias-dependent contact resistance in rubrene single-crystal field-effect transistors

    NARCIS (Netherlands)

    Molinari, A.; Gutiérrez, I.; Hulea, I.N.; Russo, S.; Morpurgo, A.F.

    2007-01-01

    The authors report a systematic study of the bias-dependent contact resistance in rubrene single-crystal field-effect transistors with Ni, Co, Cu, Au, and Pt electrodes. They show that the reproducibility in the values of contact resistance strongly depends on the metal, ranging from a factor of 2 f

  10. Polymer Electro-optic Modulator Linear Bias Using the Thermo-optic Effect

    Institute of Scientific and Technical Information of China (English)

    SUN Xiao-Qiang; CHEN Chang-Ming; LI Xiao-Dong; WANG Xi-Bin; YANG Tian-Fu; ZHANG Da-Ming; WANG Fei; XIE Zhi-Yuan

    2012-01-01

    A quasi-rectangular waveguide polymer Mach-Zehnder (M-Z) electro-optic (EO) modulator based on an organic/inorganic hybrid material with thermal bias control is fabricated and demonstrated. Linear bias for the modulator is obtained through thermo-optic effect. The optical output is adjusted by changing phase difference between the two arms of the M-Z interferometer. A power consumption of 16.1 mW for π phase change is observed owing to the application of silica cladding. This approach is proved to be effective to suppress direct current drift in polymer EO modulators.%A quasi-rectangular waveguide polymer Mach-Zehnder (M-Z) electro-optic (EO) modulator based on an organic/inorganic hybrid material with thermal bias control is fabricated and demonstrated.Linear bias for the modulator is obtained through thermo-optic effect.The optical output is adjusted by changing phase difference between the two arms of the M-Z interferometer.A power consumption of 16.1 m W for π phase change is observed owing to the application of silica cladding.This approach is proved to be effective to suppress direct current drift in polymer EO modulators.

  11. Towards a de-biased social psychology: The effects of ideological perspective go beyond politics.

    Science.gov (United States)

    Funder, David C

    2015-01-01

    Reasonable conservatives are in short supply and will not arrive to save social psychology any time soon. The field needs to save itself through de-biasing. The effects of a liberal worldview permeate and distort discussion of many topics that are not overtly political, including behavioral genetics and evolutionary psychology, the fundamental attribution error, and the remarkably persistent consistency controversy.

  12. Size-dependent effects in exchange-biased planar Hall effect sensor crosses

    DEFF Research Database (Denmark)

    Donolato, Marco; Dalslet, Bjarke Thomas; Damsgaard, Christian Danvad

    2011-01-01

    Exchange-biased planar Hall effect magnetic field sensor crosses with arm width w have been studied as function of w. For large values of w, the magnetic behavior is hysteresis-free and follows the single domain Stoner-Wohlfarth model. When w is decreased, hysteresis is observed in the sensor...... response. For intermediate values of w, the magnetization reversal takes place in two steps, and for small values of w, the magnetization reversal takes place in a single step. Based on electrical measurements, magnetic force microscopy, and micromagnetic simulations, the observations are explained...... by an increasing magnetic shape anisotropy of the arms of the cross. We propose a simple analytical model that captures the essential physics of the observations and parameterizes the effects of the cross-shape on the central part of the cross. (C) 2011 American Institute of Physics. [doi:10.1063/1.3561364]...

  13. Innovative Liner Concepts: Experiments and Impedance Modeling of Liners Including the Effect of Bias Flow

    Science.gov (United States)

    Kelly, Jeff; Betts, Juan Fernando; Fuller, Chris

    2000-01-01

    The study of normal impedance of perforated plate acoustic liners including the effect of bias flow was studied. Two impedance models were developed by modeling the internal flows of perforate orifices as infinite tubes with the inclusion of end corrections to handle finite length effects. These models assumed incompressible and compressible flows, respectively, between the far field and the perforate orifice. The incompressible model was used to predict impedance results for perforated plates with percent open areas ranging from 5% to 15%. The predicted resistance results showed better agreement with experiments for the higher percent open area samples. The agreement also tended to deteriorate as bias flow was increased. For perforated plates with percent open areas ranging from 1% to 5%, the compressible model was used to predict impedance results. The model predictions were closer to the experimental resistance results for the 2% to 3% open area samples. The predictions tended to deteriorate as bias flow was increased. The reactance results were well predicted by the models for the higher percent open area, but deteriorated as the percent open area was lowered (5%) and bias flow was increased. A fit was done on the incompressible model to the experimental database. The fit was performed using an optimization routine that found the optimal set of multiplication coefficients to the non-dimensional groups that minimized the least squares slope error between predictions and experiments. The result of the fit indicated that terms not associated with bias flow required a greater degree of correction than the terms associated with the bias flow. This model improved agreement with experiments by nearly 15% for the low percent open area (5%) samples when compared to the unfitted model. The fitted model and the unfitted model performed equally well for the higher percent open area (10% and 15%).

  14. Effect of stress on structural brain asymmetry.

    Science.gov (United States)

    Zach, Petr; Vales, Karel; Stuchlik, Ales; Cermakova, Pavla; Mrzilkova, Jana; Koutela, Antonella; Kutova, Martina

    2016-09-01

    There is a growing body of evidence that stressful events may affect the brain not only as a whole, but also in multiple laterality aspects. The present review is aimed at discussing the effect of stress and stress hormones on structural brain asymmetry. Differences and crossroads of functional and structural asymmetry are briefly mentioned throughout the document. The first part of this review summarizes major findings in the field of structural brain asymmetries in animals and humans from the evolutionary perspective. Additionally, effect of stress on animals is discussed generally. The second part then explores asymmetrical effects of stress on structural changes of principal brain areas - amygdala, hippocampus, neocortex, diencephalon, basal forebrain and basal ganglia from the point of normal lateralization, steroids, trauma and genetic factors. At the end we present hypothesis why stress appears to have asymmetrical effects on lateralized brain structures.

  15. Hostile Attributional Bias, Negative Emotional Responding, and Aggression in Adults: Moderating Effects of Gender and Impulsivity

    OpenAIRE

    2012-01-01

    The current study examined the main effects of hostile attributional bias (HAB) and negative emotional responding on a variety of aggressive behaviors in adults, including general aggression, physical aggression, relational aggression, and verbal aggression. Effects of both externalizing (anger) and internalizing (embarrassment/upset) negative emotions were considered. In addition, the moderating roles of gender and impulsivity on the effects of HAB and negative emotional responding were expl...

  16. Setting temperature effect in polycrystalline exchange-biased IrMn/CoFe bilayers

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-Outon, L. E.; Araujo Filho, M. S.; Araujo, R. E.; Ardisson, J. D.; Macedo, W. A. A. [Laboratorio de Fisica Aplicada, Centro de Desenvolvimento da Tecnologia Nuclear, 31270-901 Belo Horizonte, MG (Brazil)

    2013-05-07

    We study the effect of atomic interdiffusion on the exchange bias of polycrystalline IrMn/({sup 57}Fe + CoFe) multilayers due to the thermal setting process of exchange coupling during field annealing. Depth-resolved {sup 57}Fe conversion electron Moessbauer spectroscopy was used to quantify atomic interdiffusion. Vibrating sample magnetometry was used to monitor the variation of exchange bias and magnetisation. It was found that interface sharpness is only affected above {approx}350 Degree-Sign C. Three different stages for the setting of exchange bias can be inferred from our results. At the lower setting temperatures (up to 350 Degree-Sign C), the effect of field annealing involves alignment of spins and interfacial coupling due to the setting of both antiferromagnetic (AF) bulk and interface without significant interdiffusion. At a second stage (350-450 Degree-Sign C), where AF ordering dominates over diffusion effects, atomic migration and increased setting of AF spins co-exist to produce a peak in exchange bias field and coercivity. On a third stage (>450 Degree-Sign C), severe chemical intermixing reduces significantly the F/AF coupling.

  17. Setting temperature effect in polycrystalline exchange-biased IrMn/CoFe bilayers

    Science.gov (United States)

    Fernandez-Outon, L. E.; Araújo Filho, M. S.; Araújo, R. E.; Ardisson, J. D.; Macedo, W. A. A.

    2013-05-01

    We study the effect of atomic interdiffusion on the exchange bias of polycrystalline IrMn/(57Fe + CoFe) multilayers due to the thermal setting process of exchange coupling during field annealing. Depth-resolved 57Fe conversion electron Mössbauer spectroscopy was used to quantify atomic interdiffusion. Vibrating sample magnetometry was used to monitor the variation of exchange bias and magnetisation. It was found that interface sharpness is only affected above ˜350 °C. Three different stages for the setting of exchange bias can be inferred from our results. At the lower setting temperatures (up to 350 °C), the effect of field annealing involves alignment of spins and interfacial coupling due to the setting of both antiferromagnetic (AF) bulk and interface without significant interdiffusion. At a second stage (350-450 °C), where AF ordering dominates over diffusion effects, atomic migration and increased setting of AF spins co-exist to produce a peak in exchange bias field and coercivity. On a third stage (>450 °C), severe chemical intermixing reduces significantly the F/AF coupling.

  18. Effective stress coefficient for uniaxial strain condition

    DEFF Research Database (Denmark)

    Alam, M.M.; Fabricius, I.L.

    2012-01-01

    The effective stress coefficient, introduced by Biot, is used for predicting effective stress or pore pressure in the subsurface. It is not a constant value. It is different for different types of sediment and it is stress dependent. We used a model, based on contact between the grains to describ...... determined under uniaxial strain condition will be more relevant in reservoir studies. Copyright 2012 ARMA, American Rock Mechanics Association....

  19. Reduction of Pavlovian Bias in Schizophrenia: Enhanced Effects in Clozapine-Administered Patients.

    Directory of Open Access Journals (Sweden)

    Matthew A Albrecht

    Full Text Available The negative symptoms of schizophrenia (SZ are associated with a pattern of reinforcement learning (RL deficits likely related to degraded representations of reward values. However, the RL tasks used to date have required active responses to both reward and punishing stimuli. Pavlovian biases have been shown to affect performance on these tasks through invigoration of action to reward and inhibition of action to punishment, and may be partially responsible for the effects found in patients. Forty-five patients with schizophrenia and 30 demographically-matched controls completed a four-stimulus reinforcement learning task that crossed action ("Go" or "NoGo" and the valence of the optimal outcome (reward or punishment-avoidance, such that all combinations of action and outcome valence were tested. Behaviour was modelled using a six-parameter RL model and EEG was simultaneously recorded. Patients demonstrated a reduction in Pavlovian performance bias that was evident in a reduced Go bias across the full group. In a subset of patients administered clozapine, the reduction in Pavlovian bias was enhanced. The reduction in Pavlovian bias in SZ patients was accompanied by feedback processing differences at the time of the P3a component. The reduced Pavlovian bias in patients is suggested to be due to reduced fidelity in the communication between striatal regions and frontal cortex. It may also partially account for previous findings of poorer "Go-learning" in schizophrenia where "Go" responses or Pavlovian consistent responses are required for optimal performance. An attenuated P3a component dynamic in patients is consistent with a view that deficits in operant learning are due to impairments in adaptively using feedback to update representations of stimulus value.

  20. Phase separation and exchange bias effect in Ca doped EuCrO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Dongmei, E-mail: dmdeng@shu.edu.cn [Department of Physics and Materials Genome Institute, Shanghai University, Shanghai 200444 (China); Wang, Xingyu; Zheng, Jiashun; Qian, Xiaolong [Department of Physics and Materials Genome Institute, Shanghai University, Shanghai 200444 (China); Yu, Dehong; Sun, Dehui [Bragg Institute, Australian Nuclear Science and Technology Organization, Kirrawee DC, NSW 2232 (Australia); Jing, Chao [Department of Physics and Materials Genome Institute, Shanghai University, Shanghai 200444 (China); Lu, Bo [Analysis and Measurement Center and Laboratory for Microstructures of Shanghai University, Shanghai 200444 (China); Kang, Baojuan; Cao, Shixun; Zhang, Jincang [Department of Physics and Materials Genome Institute, Shanghai University, Shanghai 200444 (China)

    2015-12-01

    The rare-earth chromites have attracted increasing interests in recent years, as a member of a few single-phase multiferroic materials. We studied the structure and magnetic property of a series of Ca-doped EuCrO{sub 3} samples by using X-ray powder diffraction and Physical Property Measurement System. Phase separation, rotation of magnetization in M(T) curve and exchange bias effect have been identified. The Eu{sub 0.7}Ca{sub 0.3}CrO{sub 3} polycrystalline sample may be intrinsically phase-separated, with Cr{sup 3+}-rich, Cr{sup 4+}-rich canted antiferromagnetic regions surrounded by spin glass-like frustrated phase, resulting in several magnetic features including: (1) a broad and slow increase of M(T) curve with the decrease of temperature; (2) rotation of magnetization with increasing cooling field; (3) exchange bias and glassy magnetism. The rotation of magnetization is ascribed to the rotation of the moment of Cr{sup 4+}-rich regions, arising from the competition between exchange coupling energy and magnetostatic energy. The exchange bias effect suggests the formation of weak ferromagnetic unidirectional anisotropy during field cooling, due to the exchange coupling among weak ferromagnetic domains and surrounding spin glass-like regions. This result helps understanding the interaction among different magnetic domains and phases in a complex system. - Highlights: • Exchange bias effect and glassy magnetism were observed in Eu{sub 0.7}Ca{sub 0.3}CrO{sub 3}. • Rotation of the moments of Cr{sup 4+}-rich regions result in the rotation of magnetization in M(T) curve. • Spin glass-like regions contribute to the observed exchange bias effect.

  1. Exchange bias effect in BiFeO{sub 3}-NiO nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Chakrabarti, Kaushik; Sarkar, Babusona; Dev Ashok, Vishal; Das, Kajari; De, S. K., E-mail: msskd@iacs.res.in [Department of Materials Science, Indian Association For the Cultivation of Science, Jadavpur, Kolkata 700032 (India); Sinha Chaudhuri, Sheli [Department of Electronics and Telecommunication Engineering, Jadavpur University, Jadavpur, Kolkata 700032 (India); Mitra, Amitava [Material Science and Technology Division, CSIR-National Metallurgical Laboratory, Jamshedpur 7 (India)

    2014-01-07

    Ferromagnetic BiFeO{sub 3} nanocrystals of average size 11 nm were used to form nanocomposites (x)BiFeO{sub 3}/(100 − x)NiO, x = 0, 20, 40, 50, 60, 80, and 100 by simple solvothermal process. The ferromagnetic BiFeO{sub 3} nanocrystals embedded in antiferromagnetic NiO nanostructures were confirmed from X-ray diffraction and transmission electron microscope studies. The modification of cycloidal spin structure of bulk BiFeO{sub 3} owing to reduction in particle size compared to its spin spiral wavelength (62 nm) results in ferromagnetic ordering in pure BiFeO{sub 3} nanocrystals. High Neel temperature (T{sub N}) of NiO leads to significant exchange bias effect across the BiFeO{sub 3}/NiO interface at room temperature. A maximum exchange bias field of 123.5 Oe at 300 K for x = 50 after field cooling at 7 kOe has been observed. The exchange bias coupling causes an enhancement of coercivity up to 235 Oe at 300 K. The observed exchange bias effect originates from the exchange coupling between the surface uncompensated spins of BiFeO{sub 3} nanocrystals and NiO nanostructures.

  2. Exchange bias effect in composites of cuo nanoparticles and nanosilica glass

    Energy Technology Data Exchange (ETDEWEB)

    Ranjan Saha, Dhriti [MLS Professor' s Unit, Indian Association for the Cultivation of Science, 2A and 2B Raja S.C. Mullick Road, Jadavpur, Kolkata 700032 (India); Kumar Nandi, Arun [Polymer Science Unit, Indian Association for the Cultivation of Science, 2A and 2B Raja S.C. Mullick Road, Jadavpur, Kolkata 700032 (India); Chakravorty, Dipankar, E-mail: mlsdc@iacs.res.in [MLS Professor' s Unit, Indian Association for the Cultivation of Science, 2A and 2B Raja S.C. Mullick Road, Jadavpur, Kolkata 700032 (India)

    2014-04-15

    Nanodimensional silica based glass containing iron ions was prepared within the compressed pellet of CuO nanoparicles. The nanocomposite material showed exchange bias effect. This effect arose due to ferromagnetic iron doped CuO phase and antiferromagnetic CuO interface formation within the nanocomposite during the synthesis process. Coercive field as a function of temperature was fitted with Arhenius–Neel equation and extracted blocking temperature was 511 K. The value of effective anisotropy constant for the nanocomposite was found to be 3.64x10{sup 5} erg/cc. - Highlights: • Nanoglass comprising SiO{sub 2} and Fe{sub 2}O{sub 3} was grown with pores of CuO nanoparticle compacts. • CuO (AFM)-core and Fe doped CuO (FM) shell were formed during synthesis. • The nanocomposite material showed exchange bias effect.

  3. Biases in Social Comparative Judgments: The Role of Nonmotivated Factors in Above-Average and Comparative-Optimism Effects

    Science.gov (United States)

    Chambers, John R.; Windschitl, Paul D.

    2004-01-01

    Biases in social comparative judgments, such as those illustrated by above-average and comparative-optimism effects, are often regarded as products of motivated reasoning (e.g., self-enhancement). These effects, however, can also be produced by information-processing limitations or aspects of judgment processes that are not necessarily biased by…

  4. Edge effects in the directionally biased distribution of Choristoneura rosaceana (Lepidoptera: Tortricidae) in apple orchards.

    Science.gov (United States)

    Hsu, C L; Agnello, A M; Reissig, W H

    2009-04-01

    Edge effect tests have been used in a number of studies on obliquebanded leafroller, Choristoneura rosaceana (Harris), to test for evidence of mated female immigration into pheromone-treated orchards. This type of test compares obliquebanded leafroller presence or activity around the perimeter of an orchard against presence or activity in the interior. Higher numbers detected around the edges of an orchard would indicate higher levels of flight activity at the edge, a pattern that could be generated by high levels of immigration. Recent work has shown that the spatial distribution of recaptured obliquebanded leafroller adults released from a single location can be directionally biased, which could obscure the ability to detect an edge effect. To test this theory, data from an orchard study conducted in 1991 that found no significant edge effect was reanalyzed. When we accounted for the directional bias in the distribution of first-generation mated female moths, we found an edge effect with significantly more mated females captured in the edge traps than in the center or mid-interior traps. No edge effect was found when the directional bias was ignored. In addition, second-generation males and mated females both showed a significant edge effect that had not been detected in the original analysis, which had combined both first- and second-generation data.

  5. Bridging exchange bias effect in NiO and Ni(core)@NiO(shell) nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Rinaldi-Montes, Natalia, E-mail: nataliarin@gmail.com [Departamento de Física, Universidad de Oviedo, E-33007 Oviedo (Spain); Gorria, Pedro [Departamento de Física & IUTA, EPI, Universidad de Oviedo, E-33203 Gijón (Spain); Martínez-Blanco, David [Servicios Científico-Técnicos, Universidad de Oviedo, E-33006 Oviedo (Spain); Fuertes, Antonio B. [Instituto Nacional del Carbón, CSIC, E-33080 Oviedo (Spain); Fernández Barquín, Luis [CITIMAC, Facultad de Ciencias, Universidad de Cantabria, E-39005 Santander (Spain); Puente-Orench, Inés [Instituto de Ciencia de Materiales de Aragón, CSIC-Universidad de Zaragoza and Institut Laue-Langevin, BP 156, F-38042 Grenoble Cedex 9 (France); Blanco, Jesús A. [Departamento de Física, Universidad de Oviedo, E-33007 Oviedo (Spain)

    2016-02-15

    Among all bi-magnetic core(transition metal)@shell(transition metal oxide) nanoparticles (NPs), Ni@NiO ones show an onset temperature for the exchange bias (EB) effect far below the Néel temperature of bulk antiferromagnetic NiO. In this framework, the role played by the magnetism of NiO at the nanoscale is investigated by comparing the microstructure and magnetic properties of NiO and Ni@NiO NPs. With the aim of bridging the two systems, the diameter of the NiO NPs (~4 nm) is chosen to be comparable to the shell thickness of Ni@NiO ones (~2 nm). The EB effect in Ni@NiO NPs is attributed to the exchange coupling between the core and the shell, with an interfacial exchange energy of ΔE~0.06 erg cm{sup −2}, thus comparable to previous reports on Ni/NiO interfaces both in thin film and NP morphologies. In contrast, the EB detected in NiO NPs is explained in a picture where uncompensated spins located on a magnetically disordered surface shell are exchange coupled to the antiferromagnetic core. In all the studied NPs, the variation of the EB field as a function of temperature is described according to a negative exponential law with a similar decay constant, yielding a vanishing EB effect around T~40–50 K. In addition, the onset temperature for the EB effect in both NiO and Ni@NiO NPs seems to follow a universal dependence with the NiO crystallite size. - Highlights: • Comparison of the exchange bias effect in NiO and Ni(core)@NiO(shell) nanoparticles. • Universal temperature dependence of the exchange bias effect. • Suggested similar physical origin of the effect in both systems. • Size and crystallinity of the NiO shell hold the key for exchange bias properties.

  6. Phantom behavioral assimilation effects: systematic biases in social comparison choice studies.

    Science.gov (United States)

    Marsh, Herbert W; Seaton, Marjorie; Kuyper, Hans; Dumas, Florence; Huguet, Pascal; Régner, Isabelle; Buunk, Abraham P; Monteil, Jean-Marc; Gibbons, Frederick X

    2010-04-01

    Consistent with social comparison theory (SCT), Blanton, Buunk, Gibbons, and Kuyper (1999) and Huguet, Dumas, Monteil, and Genestoux (2001) found that students tended to choose comparison targets who slightly outperformed them (i.e., upward comparison choices), and this had a beneficial effect on subsequent performance--a behavioral assimilation effect (BAE). We show (Studies 1 and 2) that this apparent BAE is due, in part, to uncontrolled measurement error in pretest achievement. However, using simulated data (Study 3), these phantom BAEs were eliminated with latent-variable models with multiple indicators. In Studies 4 and 5, latent-variable models were applied to the Blanton et al. and Huguet et al. data, resulting in substantially smaller but still significantly positive BAEs. More generally in personality research based on correlational data, failure to control measurement error in pretest/background variables will positively bias the apparent effects of personality variables of interest, but widely applicable approaches demonstrated here can correct for these biases.

  7. Bias Errors due to Leakage Effects When Estimating Frequency Response Functions

    Directory of Open Access Journals (Sweden)

    Andreas Josefsson

    2012-01-01

    Full Text Available Frequency response functions are often utilized to characterize a system's dynamic response. For a wide range of engineering applications, it is desirable to determine frequency response functions for a system under stochastic excitation. In practice, the measurement data is contaminated by noise and some form of averaging is needed in order to obtain a consistent estimator. With Welch's method, the discrete Fourier transform is used and the data is segmented into smaller blocks so that averaging can be performed when estimating the spectrum. However, this segmentation introduces leakage effects. As a result, the estimated frequency response function suffers from both systematic (bias and random errors due to leakage. In this paper the bias error in the H1 and H2-estimate is studied and a new method is proposed to derive an approximate expression for the relative bias error at the resonance frequency with different window functions. The method is based on using a sum of real exponentials to describe the window's deterministic autocorrelation function. Simple expressions are derived for a rectangular window and a Hanning window. The theoretical expressions are verified with numerical simulations and a very good agreement is found between the results from the proposed bias expressions and the empirical results.

  8. Shape-dependent exchange bias effect in magnetic nanoparticles with core-shell morphology

    Science.gov (United States)

    Dimitriadis, V.; Kechrakos, D.; Chubykalo-Fesenko, O.; Tsiantos, V.

    2015-08-01

    We study the low-temperature isothermal magnetic hysteresis of cubical and spherical nanoparticles with ferromagnetic-core/antiferromagnetic-shell morphology, in order to elucidate the sensitivity of the exchange bias effect to the shape of the particles and the structural imperfections at the core-shell interface. We model the magnetic structure using a classical Heisenberg Hamiltonian with uniaxial anisotropy and simulate the hysteresis loop using the metropolis Monte Carlo algorithm. For nanoparticles with geometrically sharp interfaces, we find that cubes exhibit a higher coercivity and lower exchange bias field than spheres of the same size. With increasing interface roughness, the shape dependence of the characteristic fields gradually decays, and eventually, the distinction between cubical and spherical particles is lost for moderately rough interfaces. The sensitivity of the exchange bias field to the microstructural details of the interface is quantified by a scaling factor (b ) relating the bias field to the net moment of the antiferromagnetic shell (Heb=b MAF+Ho) . Cubical particles exhibit a lower sensitivity to the dispersed values of the net interfacial moment.

  9. [The effects of interpretation bias for social events and automatic thoughts on social anxiety].

    Science.gov (United States)

    Aizawa, Naoki

    2015-08-01

    Many studies have demonstrated that individuals with social anxiety interpret ambiguous social situations negatively. It is, however, not clear whether the interpretation bias discriminatively contributes to social anxiety in comparison with depressive automatic thoughts. The present study investigated the effects of negative interpretation bias and automatic thoughts on social anxiety. The Social Intent Interpretation-Questionnaire, which measures the tendency to interpret ambiguous social events as implying other's rejective intents, the short Japanese version of the Automatic Thoughts Questionnaire-Revised, and the Anthropophobic Tendency Scale were administered to 317 university students. Covariance structure analysis indicated that both rejective intent interpretation bias and negative automatic thoughts contributed to mental distress in social situations mediated by a sense of powerlessness and excessive concern about self and others in social situations. Positive automatic thoughts reduced mental distress. These results indicate the importance of interpretation bias and negative automatic thoughts in the development and maintenance of social anxiety. Implications for understanding of the cognitive features of social anxiety were discussed.

  10. Food stress causes sex-specific maternal effects in mites.

    Science.gov (United States)

    Walzer, Andreas; Schausberger, Peter

    2015-08-01

    Life history theory predicts that females should produce few large eggs under food stress and many small eggs when food is abundant. We tested this prediction in three female-biased size-dimorphic predatory mites feeding on herbivorous spider mite prey: Phytoseiulus persimilis, a specialized spider mite predator; Neoseiulus californicus, a generalist preferring spider mites; Amblyseius andersoni, a broad diet generalist. Irrespective of predator species and offspring sex, most females laid only one small egg under severe food stress. Irrespective of predator species, the number of female but not male eggs decreased with increasing maternal food stress. This sex-specific effect was probably due to the higher production costs of large female than small male eggs. The complexity of the response to the varying availability of spider mite prey correlated with the predators' degree of adaptation to this prey. Most A. andersoni females did not oviposit under severe food stress, whereas N. californicus and P. persimilis did oviposit. Under moderate food stress, only P. persimilis increased its investment per offspring, at the expense of egg number, and produced few large female eggs. When prey was abundant, P. persimilis decreased the female egg sizes at the expense of increased egg numbers, resulting in a sex-specific egg size/number trade-off. Maternal effects manifested only in N. californicus and P. persimilis. Small egg size correlated with the body size of daughters but not sons. Overall, our study provides a key example of sex-specific maternal effects, i.e. food stress during egg production more strongly affects the sex of the large than the small offspring.

  11. Do Methodological Choices in Environmental Modeling Bias Rebound Effects? A Case Study on Electric Cars.

    Science.gov (United States)

    Font Vivanco, David; Tukker, Arnold; Kemp, René

    2016-10-18

    Improvements in resource efficiency often underperform because of rebound effects. Calculations of the size of rebound effects are subject to various types of bias, among which methodological choices have received particular attention. Modellers have primarily focused on choices related to changes in demand, however, choices related to modeling the environmental burdens from such changes have received less attention. In this study, we analyze choices in the environmental assessment methods (life cycle assessment (LCA) and hybrid LCA) and environmental input-output databases (E3IOT, Exiobase and WIOD) used as a source of bias. The analysis is done for a case study on battery electric and hydrogen cars in Europe. The results describe moderate rebound effects for both technologies in the short term. Additionally, long-run scenarios are calculated by simulating the total cost of ownership, which describe notable rebound effect sizes-from 26 to 59% and from 18 to 28%, respectively, depending on the methodological choices-with favorable economic conditions. Relevant sources of bias are found to be related to incomplete background systems, technology assumptions and sectorial aggregation. These findings highlight the importance of the method setup and of sensitivity analyses of choices related to environmental modeling in rebound effect assessments.

  12. The Effects of Static Coulomb Stress Change on Southern California Earthquake Forecasting

    Science.gov (United States)

    Strader, Anne Elizabeth

    I investigate how inclusion of static Coulomb stress changes, caused by tectonic loading and previous seismicity, contributes to the effectiveness and reliability of prospective earthquake forecasts. Several studies have shown that positive static Coulomb stress changes are associated with increased seismicity, relative to stress shadows. However, it is difficult to avoid bias when the learning and testing intervals are chosen retrospectively. I hypothesize that earthquake forecasts based on static Coulomb stress fields may improve upon existing earthquake forecasts based on historical seismicity. Within southern California, I have confirmed the aforementioned relationship between earthquake location and Coulomb stress change, but found no identifiable triggering threshold based on static Coulomb stress history at individual earthquake locations. I have also converted static Coulomb stress changes into spatially-varying earthquake rates by optimizing an index function and calculating probabilities of cells containing at least one earthquake based on Coulomb stress ranges. Inclusion of Coulomb stress effects gives an improvement in earthquake forecasts that is significant with 95% confidence, compared to smoothed seismicity null forecasts. Because of large uncertainties in Coulomb stress calculations near faults (and aftershock distributions), I combine static Coulomb stress and smoothed seismicity into a hybrid earthquake forecast. Evaluating such forecasts against those in which only Coulomb stress or smoothed seismicity determines earthquake rates indicates that Coulomb stress is more effective in the far field, whereas statistical seismology outperforms Coulomb stress near faults. Additionally, I test effects of receiver plane orientation, stress type (normal and shear components), and declustering receiver earthquakes. While static Coulomb stress shows significant potential in a prospective earthquake forecast, simplifying assumptions compromise its

  13. Adverse effects of stress on microbiota

    Science.gov (United States)

    The complex communities of microorganisms that colonize the gastrointestinal tract impact the health status of an animal. The health of an animal as well as production traits are also affected by exposure to stress. The aim of present study was to evaluate the effects of dehorning stress on the gut ...

  14. Temperature effects in exchange-biased planar Hall sensors for bioapplications

    DEFF Research Database (Denmark)

    Damsgaard, Christian Danvad; Dalslet, Bjarke Thomas; Freitas, S.C.

    2009-01-01

    The temperature dependence of exchange biased planar Hall effect sensors is investigated between T = −10 and 70 °C. It is shown that a single domain model describes the system well and that the temperature coefficient of the low-field sensitivity at T = 25 °C is 0.32%/°C. A procedure for temperat...... for temperature correction by use of a reference sensor is demonstrated. Consequences for magnetic biosensing are exemplified with calculations on M-280 Dynabeads®.......The temperature dependence of exchange biased planar Hall effect sensors is investigated between T = −10 and 70 °C. It is shown that a single domain model describes the system well and that the temperature coefficient of the low-field sensitivity at T = 25 °C is 0.32%/°C. A procedure...

  15. Low-bias negative differential resistance effect in armchair graphene nanoribbon junctions

    Energy Technology Data Exchange (ETDEWEB)

    Li, Suchun [Department of Physics, Center for Advanced 2D Materials and Graphene Research Center, National University of Singapore, 2 Science Drive 3, Singapore 117551 (Singapore); Institute of High Performance Computing, Agency for Science, Technology and Research, 1 Fusionopolis Way, #16-16 Connexis, Singapore 138632 (Singapore); NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, 28 Medical Drive, Singapore 117456 (Singapore); Gan, Chee Kwan [Institute of High Performance Computing, Agency for Science, Technology and Research, 1 Fusionopolis Way, #16-16 Connexis, Singapore 138632 (Singapore); Son, Young-Woo [Korea Institute for Advanced Study, Seoul 130-722 (Korea, Republic of); Feng, Yuan Ping [Department of Physics, Center for Advanced 2D Materials and Graphene Research Center, National University of Singapore, 2 Science Drive 3, Singapore 117551 (Singapore); NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, 28 Medical Drive, Singapore 117456 (Singapore); Quek, Su Ying, E-mail: phyqsy@nus.edu.sg [Department of Physics, Center for Advanced 2D Materials and Graphene Research Center, National University of Singapore, 2 Science Drive 3, Singapore 117551 (Singapore); Institute of High Performance Computing, Agency for Science, Technology and Research, 1 Fusionopolis Way, #16-16 Connexis, Singapore 138632 (Singapore)

    2015-01-05

    Graphene nanoribbons with armchair edges (AGNRs) have bandgaps that can be flexibly tuned via the ribbon width. A junction made of a narrower AGNR sandwiched between two wider AGNR leads was recently reported to possess two perfect transmission channels close to the Fermi level. Here, we report that by using a bias voltage to drive these transmission channels into the gap of the wider AGNR lead, we can obtain a negative differential resistance (NDR) effect. Owing to the intrinsic properties of the AGNR junctions, the on-set bias reaches as low as ∼0.2 V and the valley current almost vanishes. We further show that such NDR effect is robust against details of the atomic structure of the junction, substrate, and whether the junction is made by etching or by hydrogenation.

  16. Predicting the synergy of multiple stress effects

    Science.gov (United States)

    Liess, Matthias; Foit, Kaarina; Knillmann, Saskia; Schäfer, Ralf B.; Liess, Hans-Dieter

    2016-09-01

    Toxicants and other, non-chemical environmental stressors contribute to the global biodiversity crisis. Examples include the loss of bees and the reduction of aquatic biodiversity. Although non-compliance with regulations might be contributing, the widespread existence of these impacts suggests that for example the current approach of pesticide risk assessment fails to protect biodiversity when multiple stressors concurrently affect organisms. To quantify such multiple stress effects, we analysed all applicable aquatic studies and found that the presence of environmental stressors increases individual sensitivity to toxicants (pesticides, trace metals) by a factor of up to 100. To predict this dependence, we developed the “Stress Addition Model” (SAM). With the SAM, we assume that each individual has a general stress capacity towards all types of specific stress that should not be exhausted. Experimental stress levels are transferred into general stress levels of the SAM using the stress-related mortality as a common link. These general stress levels of independent stressors are additive, with the sum determining the total stress exerted on a population. With this approach, we provide a tool that quantitatively predicts the highly synergistic direct effects of independent stressor combinations.

  17. The quantum approach to human reasoning does explain the belief-bias effect

    CERN Document Server

    Vol, E D

    2013-01-01

    Based on the ideas of quantum physics and dual-process theory of human reasoning that takes into account two primary mechanisms of reasoning : 1) deductive rational thinking and 2) intuitive heuristic judgment, we proposed the "quantum" approach to practical human logic that allows one to specify the most distinctive peculiarities in activity of two reasoning systems mentioned above and in addition to describe phenomenologically well-established experimentally belief-bias effect.

  18. The Accumulative Effect of Concentric-Biased and Eccentric-Biased Exercise on Cardiorespiratory and Metabolic Responses to Subsequent Low-Intensity Exercise: A Preliminary Study.

    Science.gov (United States)

    Gavin, James Peter; Myers, Stephen; Willems, Mark Elisabeth Theodorus

    2015-12-22

    The study investigated the accumulative effect of concentric-biased and eccentric-biased exercise on cardiorespiratory, metabolic and neuromuscular responses to low-intensity exercise performed hours later. Fourteen young men cycled at low-intensity (~60 rpm at 50% maximal oxygen uptake) for 10 min before, and 12 h after: concentric-biased, single-leg cycling exercise (CON) (performed ~19:30 h) and eccentric-biased, double-leg knee extension exercise (ECC) (~06:30 h the following morning). Respiratory measures were sampled breath-by-breath, with oxidation values derived from stoichiometry equations. Knee extensor neuromuscular function was assessed before and after CON and ECC. Cardiorespiratory responses during low-intensity cycling were unchanged by accumulative CON and ECC. The RER was lower during low-intensity exercise 12 h after CON and ECC (0.88 ± 0.08), when compared to baseline (0.92 ± 0.09; p = 0.02). Fat oxidation increased from baseline (0.24 ± 0.2 g·min(-1)) to 12 h after CON and ECC (0.39 ± 0.2 g·min(-1); p = 0.01). Carbohydrate oxidation decreased from baseline (1.59 ± 0.4 g·min(-1)) to 12 h after CON and ECC (1.36 ± 0.4 g·min(-1); p = 0.03). These were accompanied by knee extensor force loss (right leg: -11.6%, p eccentric-biased exercise led to increased fat oxidation and decreased carbohydrate oxidation, without impairing cardiorespiration, during low-intensity cycling. An accumulation of fatiguing and damaging exercise increases fat utilisation during low intensity exercise performed as little as 12 h later.

  19. Thermophysical Property Estimation by Transient Experiments: The Effect of a Biased Initial Temperature Distribution

    Directory of Open Access Journals (Sweden)

    Federico Scarpa

    2015-01-01

    Full Text Available The identification of thermophysical properties of materials in dynamic experiments can be conveniently performed by the inverse solution of the associated heat conduction problem (IHCP. The inverse technique demands the knowledge of the initial temperature distribution within the material. As only a limited number of temperature sensors (or no sensor at all are arranged inside the test specimen, the knowledge of the initial temperature distribution is affected by some uncertainty. This uncertainty, together with other possible sources of bias in the experimental procedure, will propagate in the estimation process and the accuracy of the reconstructed thermophysical property values could deteriorate. In this work the effect on the estimated thermophysical properties due to errors in the initial temperature distribution is investigated along with a practical method to quantify this effect. Furthermore, a technique for compensating this kind of bias is proposed. The method consists in including the initial temperature distribution among the unknown functions to be estimated. In this way the effect of the initial bias is removed and the accuracy of the identified thermophysical property values is highly improved.

  20. Implementing a generic method for bias correction in statistical models using random effects, with spatial and population dynamics examples

    DEFF Research Database (Denmark)

    Thorson, James T.; Kristensen, Kasper

    2016-01-01

    configurations of an age-structured population dynamics model. This simulation experiment shows that the epsilon-method and the existing bias-correction method perform equally well in data-rich contexts, but the epsilon-method is slightly less biased in data-poor contexts. We then apply the epsilon....... Quantities of biological or management interest ("derived quantities") are then often calculated as nonlinear functions of fixed and random effect estimates. However, the conventional "plug-in" estimator for a derived quantity in a maximum likelihood mixed-effects model will be biased whenever the estimator...... is calculated as a nonlinear function of random effects. We therefore describe and evaluate a new "epsilon" estimator as a generic bias-correction estimator for derived quantities. We use simulated data to compare the epsilon-method with an existing bias-correction algorithm for estimating recruitment in four...

  1. The effect of psychological stress and expectation on auditory perception: A signal detection analysis.

    Science.gov (United States)

    Hoskin, Robert; Hunter, Mike D; Woodruff, Peter W R

    2014-11-01

    Both psychological stress and predictive signals relating to expected sensory input are believed to influence perception, an influence which, when disrupted, may contribute to the generation of auditory hallucinations. The effect of stress and semantic expectation on auditory perception was therefore examined in healthy participants using an auditory signal detection task requiring the detection of speech from within white noise. Trait anxiety was found to predict the extent to which stress influenced response bias, resulting in more anxious participants adopting a more liberal criterion, and therefore experiencing more false positives, when under stress. While semantic expectation was found to increase sensitivity, its presence also generated a shift in response bias towards reporting a signal, suggesting that the erroneous perception of speech became more likely. These findings provide a potential cognitive mechanism that may explain the impact of stress on hallucination-proneness, by suggesting that stress has the tendency to alter response bias in highly anxious individuals. These results also provide support for the idea that top-down processes such as those relating to semantic expectation may contribute to the generation of auditory hallucinations.

  2. Enhanced effects of combined cognitive bias modification and computerised cognitive behaviour therapy on social anxiety

    Directory of Open Access Journals (Sweden)

    Emma Butler

    2015-12-01

    Full Text Available This study examines whether combined cognitive bias modification for interpretative biases (CBM-I and computerised cognitive behaviour therapy (C-CBT can produce enhanced positive effects on interpretation biases and social anxiety. Forty socially anxious students were randomly assigned into two conditions, an intervention group (positive CBM-I + C-CBT or an active control (neutral CBM-I + C-CBT. At pre-test, participants completed measures of social anxiety, interpretative bias, cognitive distortions, and social and work adjustment. They were exposed to 6 × 30 min sessions of web-based interventions including three sessions of either positive or neutral CBM-I and three sessions of C-CBT, one session per day. At post-test and two-week follow-up, participants completed the baseline measures. A combined positive CBM-I + C-CBT produced less negative interpretations of ambiguous situations than neutral CBM-I + C-CBT. The results also showed that both positive CBM-I + C-CBT and neutral CBM-I + C-CBT reduced social anxiety and cognitive distortions as well as improving work and social adjustment. However, greater effect sizes were observed in the positive CBM-I + C-CBT condition than the control. This indicates that adding positive CBM-I to C-CBT enhanced the training effects on social anxiety, cognitive distortions, and social and work adjustment compared to the neutral CBM-I + C-CBT condition.

  3. Exchange bias effect in composites of cuo nanoparticles and nanosilica glass

    Science.gov (United States)

    Ranjan Saha, Dhriti; Kumar Nandi, Arun; Chakravorty, Dipankar

    2014-04-01

    Nanodimensional silica based glass containing iron ions was prepared within the compressed pellet of CuO nanoparicles. The nanocomposite material showed exchange bias effect. This effect arose due to ferromagnetic iron doped CuO phase and antiferromagnetic CuO interface formation within the nanocomposite during the synthesis process. Coercive field as a function of temperature was fitted with Arhenius-Neel equation and extracted blocking temperature was 511 K. The value of effective anisotropy constant for the nanocomposite was found to be 3.64x105 erg/cc.

  4. Does attention redirection contribute to the effectiveness of attention bias modification on social anxiety?

    Science.gov (United States)

    Yao, Nisha; Yu, Hongyu; Qian, Mingyi; Li, Songwei

    2015-12-01

    Attention bias modification (ABM) is designed to modify threat-related attention bias and thus alleviate anxiety. The current research examined whether consistently directing attention towards targeted goals per se contributes to ABM efficacy. We randomly assigned 68 non-clinical college students with elevated social anxiety to non-valence-specific attend-to-geometrics (AGC), attention modification (AMC), or attention control (ACC) conditions. We assessed subjective, behavioral, and physiological reactivity to a speech task and self-reported social anxiety symptoms. After training, participants in the AMC exhibited an attention avoidance from threat, and those in the AGC responded more rapidly toward targeted geometrics. There was a significant pre- to post-reduction in subjective speech distress across groups, but behavioral and physiological reactivity to speech, as well as self-report social anxiety symptoms, remained unchanged. These results lead to questions concerning effectiveness of ABM training for reducing social anxiety. Further examination of the current ABM protocol is required.

  5. Exchange bias effect in nickel zinc ferrite–mesoporous silica nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Banerjee, Shilpi [MLS Professor' s Unit, Indian Association for the Cultivation of Science, Kolkata 700032 (India); Department of Materials Science, Indian Association for the Cultivation of Science, Kolkata 700032 (India); Hajra, Partha [MLS Professor' s Unit, Indian Association for the Cultivation of Science, Kolkata 700032 (India); Mada, Mykanth Reddy [School of Materials Science and Engineering, University of New South Wales, Kensington, Sydney-2052 (Australia); Bhaumik, Asim [Department of Materials Science, Indian Association for the Cultivation of Science, Kolkata 700032 (India); Bandyopadhyay, Sri [School of Materials Science and Engineering, University of New South Wales, Kensington, Sydney-2052 (Australia); Chakravorty, Dipankar, E-mail: mlsdc@iacs.res.in [MLS Professor' s Unit, Indian Association for the Cultivation of Science, Kolkata 700032 (India)

    2013-04-15

    Nickel zinc ferrite–mesoporous silica nanocomposite (NZF–MS) was synthesized using impregnation method. The microstructure was investigated by transmission electron microscopy. A magnetic exchange bias effect was exhibited by the nanocomposites. This was ascribed to the presence of a ferromagnetic core and antiferromagnetic shell structure. Electron microscopic studies confirmed the presence of a core–shell structure with NZF forming the core. The zero-field cooled magnetization data as a function of temperature indicated the presence of an antiferromagnetic phase which is believed to be formed by the diffusion of Fe{sup 3+} or Ni{sup 2+} ions into the silica glass. - Highlights: ► Synthesis of ferrite–mesoporous silica nanocomposite (NC) using impregnation route. ► NC shows room temperature exchange bias (EB) under field cooled condition. ► NC shows EB due to diffusion of Fe{sup 3+}/Ni{sup 2+} from ferrite to the silica glass.

  6. Observation of an atomic exchange bias effect in DyCo4 film

    Science.gov (United States)

    Chen, Kai; Lott, Dieter; Radu, Florin; Choueikani, Fadi; Otero, Edwige; Ohresser, Philippe

    2015-12-01

    The fundamental important and technologically widely employed exchange bias effect occurs in general in bilayers of magnetic thin films consisting of antiferromagnetic and ferromagnetic layers where the hard magnetization behavior of an antiferromagnetic thin film causes a shift in the magnetization curve of a soft ferromagnetic film. The minimization of the single magnetic grain size to increase the storage density and the subsequent demand for magnetic materials with very high magnetic anisotropy requires a system with high HEB. Here we report an extremely high HEB of 4 Tesla observed in a single amorphous DyCo4 film close to room temperature. The origin of the exchange bias can be associated with the variation of the magnetic behavior from the surface towards the bulk part of the film revealed by X-ray absorption spectroscopy and X-ray magnetic circular dichroism techniques utilizing the bulk sensitive transmission and the surface sensitive total electron yield modes. The competition between the atomic exchange coupling in the single film and the Zeeman interaction lead to an intrinsic exchanged coupled system and the so far highest exchange bias effect HEB = 4 Tesla reported in a single film, which is accommodated by a partial domain wall formation.

  7. Male mutation bias and possible long-term effects of human activities.

    Science.gov (United States)

    Cotton, Samuel; Wedekind, Claus

    2010-10-01

    The ability of a population to adapt to changing environments depends critically on the amount and kind of genetic variability it possesses. Mutations are an important source of new genetic variability and may lead to new adaptations, especially if the population size is large. Mutation rates are extremely variable between and within species, and males usually have higher mutation rates as a result of elevated rates of male germ cell division. This male bias affects the overall mutation rate. We examined the factors that influence male mutation bias, and focused on the effects of classical life-history parameters, such as the average age at reproduction and elevated rates of sperm production in response to sexual selection and sperm competition. We argue that human-induced changes in age at reproduction or in sexual selection will affect male mutation biases and hence overall mutation rates. Depending on the effective population size, these changes are likely to influence the long-term persistence of a population.

  8. The anomalous exchange bias effect in core-shell Co/CoO nanoparticles

    Science.gov (United States)

    Feygenson, Mikhail; Yuen, Yiu; Kim, Kisub; Aronson, Meigan

    2008-03-01

    We study the anomalous exchange bias effect in Co/CoO nanoparticles by means of neutron and x-ray scattering and magnetic experiments. The Co nanoparticles were prepared in oleic acid by thermal decomposition of Co2(CO)8 and were subsequently oxidized. Co core- CoO shell nanoparticles with differing core and shell dimensions were obtained. The magnetic measurements indicated that there is an optimal ratio of the core and shell dimensions which maximizes the exchange bias field. Anomalous small angle x-ray scattering experiments using core-shell contrast and energy analysis provide high accuracy measurements of the core and shell, and their respective size distributions. Neutron diffraction measurements find that oxidation introduces a new modulation wave vector for the magnetization, leading to the increasing magnetic decompensation of the core-shell interface. It is our proposal that this interface moment enhances the exchange coupling of the core and shell, and leads to the extraordinarily large exchange bias effect.

  9. Syntactic flexibility and planning scope: The effect of verb bias on advance planning during sentence recall

    Directory of Open Access Journals (Sweden)

    Maartje evan de Velde

    2014-10-01

    Full Text Available In sentence production, grammatical advance planning scope depends on contextual factors (e.g., time pressure, linguistic factors (e.g., ease of structural processing, and cognitive factors (e.g., production speed. The present study tests the influence of the availability of multiple syntactic alternatives (i.e., syntactic flexibility on the scope of advance planning during the recall of Dutch dative phrases. We manipulated syntactic flexibility by using verbs with a strong bias or a weak bias towards one structural alternative in sentence frames accepting both verbs (e.g., strong/weak bias: De ober schotelt/serveert de klant de maaltijd [voor] 'The waiter dishes out/serves the customer the meal'. To assess lexical planning scope, we varied the frequency of the first post-verbal noun (N1, Experiment 1 or the second post-verbal noun (N2, Experiment 2. In each experiment, 36 speakers produced the verb phrases in a Rapid Serial Visual Presentation (RSVP paradigm. On each trial, they read a sentence presented one word at a time, performed a short distractor task, and then saw a sentence preamble (e.g., De ober… which they had to complete to form the presented sentence. Onset latencies were compared using linear mixed effects models. N1 frequency did not produce any effects. N2 frequency only affected sentence onsets in the weak verb bias condition and especially in slow speakers. These findings highlight the dependency of planning scope during sentence recall on the grammatical properties of the verb and the frequency of post-verbal nouns. Implications for utterance planning in everyday speech are discussed.

  10. Exchange bias effect in CoCr2O4/NiO system prepared by two-step method

    Science.gov (United States)

    Wang, L. G.; Zhu, C. M.; Chen, L.; Yuan, S. L.

    2017-02-01

    CoCr2O4/NiO has been successfully synthesized through two-step method. X-ray diffraction results present the coexistence of CoCr2O4 and NiO with pure formation. Micrographs measured with scanning electron microscope and transmission electron microscope display the homogeneous and dense morphology with two kinds of nanoparticles. Exchange bias effect is observed in the sample. The exchange bias field is about 872 Oe at 10 K. As measuring temperature increases, exchange bias effect is weakened with decreasing coercive field. In addition, exchange bias field and the shift of magnetization show the linear relationship with increasing cooling field. The exchange bias behavior can be attributed to the exchange coupling at the disordered interfaces in the sample.

  11. Does exposure prediction bias health-effect estimation?: The relationship between confounding adjustment and exposure prediction.

    Science.gov (United States)

    Cefalu, Matthew; Dominici, Francesca

    2014-07-01

    In environmental epidemiology, we are often faced with 2 challenges. First, an exposure prediction model is needed to estimate the exposure to an agent of interest, ideally at the individual level. Second, when estimating the health effect associated with the exposure, confounding adjustment is needed in the health-effects regression model. The current literature addresses these 2 challenges separately. That is, methods that account for measurement error in the predicted exposure often fail to acknowledge the possibility of confounding, whereas methods designed to control confounding often fail to acknowledge that the exposure has been predicted. In this article, we consider exposure prediction and confounding adjustment in a health-effects regression model simultaneously. Using theoretical arguments and simulation studies, we show that the bias of a health-effect estimate is influenced by the exposure prediction model, the type of confounding adjustment used in the health-effects regression model, and the relationship between these 2. Moreover, we argue that even with a health-effects regression model that properly adjusts for confounding, the use of a predicted exposure can bias the health-effect estimate unless all confounders included in the health-effects regression model are also included in the exposure prediction model. While these results of this article were motivated by studies of environmental contaminants, they apply more broadly to any context where an exposure needs to be predicted.

  12. Lay Evaluation of Financial Experts: The Action Advice Effect and Confirmation Bias

    Directory of Open Access Journals (Sweden)

    Tomasz Zaleskiewicz

    2016-09-01

    Full Text Available The goal of this experimental project was to investigate lay peoples’ perceptions of epistemic authority (EA in the field of finance. EA is defined as the extent to which a source of information is treated as evidence for judgments independently of its objective expertise and based on subjective beliefs. Previous research suggested that EA evaluations are biased and that lay people tend to ascribe higher EA to experts who advise action (in the case of medical experts or confirm clients’ expectations (in the case of politicians. However, there has been no research into biases in lay evaluations of financial experts and this project is aimed to fill this gap. Experiment 1 showed that lay people tended to ascribe greater authority to financial consultants who gave more active advice to clients considering taking out a mortgage. Experiment 2 confirmed the action advice effect found in Experiment 1. However, the outcomes of Experiments 2 and – particularly – 3 suggested that this bias might also be due to clients’ desire to confirm their own opinions. Experiment 2 showed that the action advice effect was moderated by clients’ own opinions on taking loans. Lay people ascribed the greatest EA to the advisor in the scenario in which he advised taking action and where this coincided with the client’s positive opinion on the advisability of taking out a loan. In Experiment 3 only participants with a positive opinion on the financial product ascribed greater authority to experts who recommended it; participants whose opinion was negative tended to rate consultants who advised rejecting the product more highly. To conclude, these three experiments revealed that lay people ascribe higher EA to financial consultants who advise action rather than maintenance of the status quo, but this effect is limited by confirmation bias: when the client’s a priori opinion is salient, greater authority is ascribed to experts whose advice confirms it. In this

  13. Photodiode forward bias to reduce temporal effects in a-Si based flat panel detectors

    Science.gov (United States)

    Mollov, Ivan; Tognina, Carlo; Colbeth, Richard

    2008-03-01

    Lag and sensitivity modulation are well known temporal artifacts of a-Si photodiode based flat panel detectors. Both effects are caused by charge carriers being trapped in the semiconductor. Trapping and releasing of these carriers is a statistical process with time constants much longer than the frame time of flat panel detectors. One way to reduce these temporal artifacts is to keep the traps filled by applying a pulse of light over the entire detector area every frame before the x-ray exposure. This paper describes an alternative method, forward biasing the a-Si photodiodes and supplying free carriers to fill the traps. The array photodiodes are forward biased and then reversed biased again every frame between the panel readout and x-ray exposure. The method requires no change to the mechanical construction of the detector, only minor modifications of the detector electronics and no image post processing. An existing flat panel detector was modified and evaluated for lag and sensitivity modulation. The required changes of the panel configuration, readout scheme and readout timing are presented in this paper. The results of applying the new technique are presented and compared to the standard mode of operation. The improvements are better than an order of magnitude for both sensitivity modulation and lag; lowering their values to levels comparable to the scintillator afterglow. To differentiate the contribution of the a-Si array, from that of the scintillator, a large area light source was used. Possible implementations and applications of the method are discussed.

  14. Measuring the Deviation from the Linear and Deterministic Bias through Cosmic Gravitational Lensing Effects

    CERN Document Server

    Fan, Z H

    2003-01-01

    Since gravitational lensing effects directly probe inhomogeneities of dark matter, lensing-galaxy cross-correlations can provide us important information on the relation between dark matter and galaxy distributions, i.e., the bias. In this paper, we propose a method to measure the stochasticity/nonlinearity of the galaxy bias through correlation studies of the cosmic shear and galaxy number fluctuations. Specifically, we employ the aperture mass statistics $M_{ap}$ to describe the cosmic shear. We divide the foreground galaxy redshift $z_f^2/$ for each redshift bin. Then the ratio of the summation of $^2/$ over the bins to $$ gives a measure of the nonlinear/stochastic bias. Here $N_g(z_f)$ is the projected surface number density fluctuation of foreground galaxies at redshift $z_f$, and $M_{ap}$ is the aperture mass from the cosmic-shear analysis. We estimate that for a moderately deep weak-lensing survey with $z_s=1$, source galaxy surface number density $n_b=30 \\hbox {gal}/\\hbox {arcmin}^2$ and a survey are...

  15. Spatial solitons in biased photovoltaic photorefractive materials with the pyroelectric effect

    Science.gov (United States)

    Katti, Aavishkar; Yadav, R. A.

    2017-01-01

    Spatial solitons in biased photorefractive media due to the photovoltaic effect and the pyroelectric effect are investigated. The pyroelectric field considered is induced due to the heating by the incident beam's energy. These solitons can be called screening photovoltaic pyroelectric solitons. It is shown that the solitons can exist in the bright and dark realizations. The conditions for formation of these solitons are discussed. Relevant example is considered to illustrate the self trapping of such solitons. The external electric field interacts with the photovoltaic field and the pyroelectric field to either support or oppose the self trapping.

  16. Effect of Nickel Concentration on Bias Reliability and Thermal Stability of Thin-Film Transistors Fabricated by Ni-Metal-Induced Crystallization

    Science.gov (United States)

    Lai, Ming-Hui; Sermon Wu, YewChung; Huang, Jung-Jie

    2012-01-01

    Ni-metal-induced crystallization (MIC) of amorphous Si (α-Si) has been employed to fabricate low-temperature polycrystalline silicon (poly-Si) thin-film transistors (TFTs). Although the high leakage current is a major issue in the performance of conventional MIC-TFTs since Ni contamination induces deep-level state traps, it can be greatly improved by using well-known technologies to reduce Ni contamination. However, for active-matrix organic light-emitting diode (AMOLED) display applications, the bias reliability and thermal stability are major concerns especially when devices are operated under a hot carrier condition and in a high-temperature environment. It will be interesting to determine how the bias reliability and thermal stability are affected by the reduction of Ni concentration. In the study, the effect of Ni concentration on bias reliability and thermal stability was investigated. We found that a device exhibited high immunity against hot-carrier stress and elevated temperatures. These findings demonstrated that reducing the Ni concentration in MIC films was also beneficial for bias reliability and thermal stability.

  17. Exchange bias effect in spin glass CoCr2O4 nanoparticles

    Science.gov (United States)

    Zhu, Changming; Tian, Zhaoming; Wang, Liguang; Yuan, Songliu

    2015-11-01

    CoCr2O4 nanoparticles are about 5.4 nm in diameter synthesized by a hydrothermal technique. Magnetization measurements reveal that the nanoparticles exhibit a spin glass behavior below glass transition temperature. Signature of memory effect is clear in reheating curve where the step-like shape increasing with the increase of temperature is recovered after cooling process. Magnetic relaxation is performed to prove memory effect. Ageing effect is also detected in CoCr2O4 nanoparticles to verify the spin glass behavior. As temperature decreases to 5 K, which is far below the glass transition temperature, exchange bias effect can be observed clearly accompanied with a shift in field-cooled hysteresis loop. As particle size decreases to 5.4 nm, spin glass behavior appears due to the increased spin disorder effect. The spin glass phase providing a pinning force from some frozen spins to the rotatable spins gives the key to explain the exchange bias effects.

  18. Body-contact self-bias effect in partially depleted SOI-CMOS and alternatives to suppress floating body effect

    Institute of Scientific and Technical Information of China (English)

    Zhou Jianhua; Gao Minghui; S.K.Pang; Zou Shichang

    2011-01-01

    As SOI-CMOS technology nodes reach the tens of nanometer regime, body-contacts become more and more ineffective to suppress the floating body effect In this paper self-bias effect as the cause for this failure is analyzed and discussed in depth with respect to different structures and conditions Other alterative approaches to suppressing the floating body effect are also introduced and discussed.

  19. Estimation and correction of surface wind-stress bias in the Tropical Pacific with the Ensemble Kalman Filter

    NARCIS (Netherlands)

    Leeuwenburgh, O.

    2008-01-01

    The assimilation of high-quality in situ data into ocean models is known to lead to imbalanced analyses and spurious circulations when the model dynamics or the forcing contain systematic errors. Use of a bias estimation and correction scheme has been shown to significantly improve the balance of th

  20. Objects in Kepler's Mirror May be Larger Than They Appear: Bias and Selection Effects in Transiting Planet Surveys

    CERN Document Server

    Gaidos, Eric

    2012-01-01

    Statistical analyses of large surveys for transiting planets such as the Kepler mission must account for systematic errors and biases. Transit detection depends not only on the planet's radius and orbital period, but also on host star properties. Thus, a sample of stars with transiting planets may not accurately represent the target population. Moreover, targets are selected using criteria such as a limiting apparent magnitude. These selection effects, combined with uncertainties in stellar radius, lead to biases in the properties of transiting planets and their host stars. We quantify possible biases in the Kepler survey. First, Eddington bias produced by a steep planet radius distribution and uncertainties in stellar radius results in a 15-20% overestimate of planet occurrence. Second, the magnitude limit of the Kepler target catalog induces Malmquist bias towards large, more luminous stars and underestimation of the radii of about one third of candidate planets, especially those larger than Neptune. Third,...

  1. How to boost positive interpretations? A meta-analysis of the effectiveness of cognitive bias modification for interpretation.

    Science.gov (United States)

    Menne-Lothmann, Claudia; Viechtbauer, Wolfgang; Höhn, Petra; Kasanova, Zuzana; Haller, Simone P; Drukker, Marjan; van Os, Jim; Wichers, Marieke; Lau, Jennifer Y F

    2014-01-01

    The current meta-analysis explores the strength of effects of cognitive bias modification training for interpretation bias (CBM-I) on positive (i.e., adaptive) interpretations and mood as well as the training and sample characteristics influencing these effects. Data-bases were searched with the key words "interpret* bias AND training" and "interpret* bias AND modif*". Reference lists of identified articles were checked and authors of identified articles were contacted for further relevant articles and unpublished data. Studies were reviewed for inclusion with eligibility criteria being that the study (a) aimed to target interpretation biases through any kind of training, (b) assessed mood and/or interpretation bias as outcome measures, (c) allocated individuals to training conditions at random, and (d) recruited adult samples. A meta-analytic multilevel mixed-effects model was employed to assess standardized mean changes in interpretation bias, negative mood, and emotional reactivity. In addition, several training and sample characteristics were explored for their potential to enhance benign training effectiveness. On average, benign CBM-I resulted in an increase in positive interpretation bias (pcognitive and mood effects, whereas feedback about training performance and inclusion of non-benign training items (instead of including benign items only) boosted cognitive effects only. Finally, training was more effective in women (cognitive and mood effects) and presumably samples with symptomatic emotional dysregulation (cognitive effects). Although the effects of emotional dysregulation and number of training sessions could not well be distinguished, there is an indication that when used with imagery instructions and more training sessions, benign CBM-I can be employed as a useful complementary treatment to usual psychotherapies.

  2. Oxidative stress effects of thinner inhalation

    OpenAIRE

    2011-01-01

    Thinners are chemical mixtures used as industrial solvents. Humans can come into contact with thinner by occupational exposure or by intentional inhalation abuse. Thinner sniffing causes damage to the brain, kidney, liver, lung, and reproductive system. We discuss some proposed mechanism by which thinner induces damage. Recently, the induction of oxidative stress has been suggested as a possible mechanism of damage. This paper reviews the current evidence for oxidative stress effects induced ...

  3. Motional Effect on Wall Shear Stresses

    DEFF Research Database (Denmark)

    Kock, Samuel Alberg; Torben Fründ, Ernst; Yong Kim, Won

    Atherosclerosis is the leading cause of death and severe disability. Wall Shear Stress (WSS), the stress exerted on vessel walls by the flowing blood is a key factor in the development of atherosclerosis. Computational Fluid Dynamics (CFD) is widely used for WSS estimations. Most CFD simulations...... are based on static models to ease computational burden leading to inaccurate estimations. The aim of this work was to estimate the effect of vessel wall deformations (expansion and bending) on WSS levels....

  4. The effects of perceived stress, traits, mood states, and stressful daily events on salivary cortisol

    NARCIS (Netherlands)

    vanEck, M; Berkhof, H; Nicolson, N; Sulon, J

    1996-01-01

    This study examined the effects of perceived stress and related individual characteristics, mood states, and stressful daily events on salivary cortisol levels. Forty-one ''high stress'' and 46 ''low stress'' subjects were selected on the basis of Perceived Stress Scale scores from a sample of male,

  5. Threading dislocation movement in AlGaN/GaN-on-Si high electron mobility transistors under high temperature reverse bias stressing

    Directory of Open Access Journals (Sweden)

    W. A. Sasangka

    2016-09-01

    Full Text Available Dislocations are known to be associated with both physical and electrical degradation mechanisms of AlGaN/GaN-on-Si high electron mobility transistors (HEMTs. We have observed threading dislocation movement toward the gate-edges in AlGaN/GaN-on-Si HEMT under high reverse bias stressing. Stressed devices have higher threading dislocation densities (i.e. ∼5 × 109/cm2 at the gate-edges, as compared to unstressed devices (i.e. ∼2.5 × 109/cm2. Dislocation movement correlates well with high tensile stress (∼1.6 GPa at the gate-edges, as seen from inverse piezoelectric calculations and x-ray synchrotron diffraction residual stress measurements. Based on Peierls stress calculation, we believe that threading dislocations move via glide in 〈 11 2 ¯ 0 〉 / { 1 1 ¯ 00 } and 〈 11 2 ¯ 0 〉 / { 1 1 ¯ 01 } slip systems. This result illustrates the importance of threading dislocation mobility in controlling the reliability of AlGaN/GaN-on-Si HEMTs.

  6. Threading dislocation movement in AlGaN/GaN-on-Si high electron mobility transistors under high temperature reverse bias stressing

    Science.gov (United States)

    Sasangka, W. A.; Syaranamual, G. J.; Made, R. I.; Thompson, C. V.; Gan, C. L.

    2016-09-01

    Dislocations are known to be associated with both physical and electrical degradation mechanisms of AlGaN/GaN-on-Si high electron mobility transistors (HEMTs). We have observed threading dislocation movement toward the gate-edges in AlGaN/GaN-on-Si HEMT under high reverse bias stressing. Stressed devices have higher threading dislocation densities (i.e. ˜5 × 109/cm2) at the gate-edges, as compared to unstressed devices (i.e. ˜2.5 × 109/cm2). Dislocation movement correlates well with high tensile stress (˜1.6 GPa) at the gate-edges, as seen from inverse piezoelectric calculations and x-ray synchrotron diffraction residual stress measurements. Based on Peierls stress calculation, we believe that threading dislocations move via glide in / { 1 1 ¯ 00 } and / { 1 1 ¯ 01 } slip systems. This result illustrates the importance of threading dislocation mobility in controlling the reliability of AlGaN/GaN-on-Si HEMTs.

  7. A fiber-bridging model with stress gradient effects

    Science.gov (United States)

    Yi, Sun; Tao, Li

    2000-05-01

    A fiber-bridging model with stress gradient effects is proposed for unidirectional fiber-reinforced composites. The stress gradient terms are introduced by solving a micromechanical model under a non-uniform stress loading. It is shown that the stress gradient effect is significant on both the fiber-bridging stress distribution and the value of the critical load of fiber failure.

  8. Noise and stress effects on preschool personnel

    Directory of Open Access Journals (Sweden)

    Fredrik Sjödin

    2012-01-01

    Full Text Available The aim of the study was to analyze the presence of stress-related health problems among preschool employees and the way in which these reactions are related to noise and other work parameters. The investigation included 101 employees at 17 preschools in Umeå County, located in northern Sweden. Individual noise recordings and recordings in dining rooms and play halls were made at two departments from each preschool. The adverse effects on the employees were analyzed by use of different validated questionnaires and by saliva cortisol samples. Stress and energy output were pronounced among the employees, and about 30% of the staff experienced strong burnout syndromes. Mental recovery after work was low, indicated by remaining high levels of stress after work. The burnout symptoms were associated with reduced sleep quality and morning sleepiness. Cortisol levels supported the conclusion about pronounced daily stress levels of the preschool employees.

  9. Judgement bias in goats (Capra hircus): investigating the effects of human grooming.

    Science.gov (United States)

    Baciadonna, Luigi; Nawroth, Christian; McElligott, Alan G

    2016-01-01

    Animal emotional states can be investigated by evaluating their impact on cognitive processes. In this study, we used a judgement bias paradigm to determine if short-term positive human-animal interaction (grooming) induced a positive affective state in goats. We tested two groups of goats and trained them to discriminate between a rewarded and a non-rewarded location over nine training days. During training, the experimental group (n = 9) was gently groomed by brushing their heads and backs for five min over 11 days (nine training days, plus two testing days, total time 55 min). During training, the control group (n = 10) did not experience any direct interaction with the experimenter, but was kept unconstrained next to him for the same period of time. After successful completion of the training, the responses (latency time) of the two groups to reach ambiguous locations situated between the two reference locations (i.e., rewarded/non-rewarded) were compared over two days of testing. There was not a positive bias effect after the animals had been groomed. In a second experiment, 10 goats were tested to investigate whether grooming induced changes in physiological activation (i.e., heart rate and heart rate variability). Heart rate increased when goats were groomed compared to the baseline condition, when the same goats did not receive any contact with the experimenter. Also, subjects did not move away from the experimenter, suggesting that the grooming was positively accepted. The very good care and the regular positive contacts that goats received from humans at the study site could potentially account for the results obtained. Good husbandry outcomes are influenced by animals' perception of the events and this is based on current circumstances, past experiences and individual variables. Taking into account animals' individual characteristics and identifying effective strategies to induce positive emotions could increase the understanding and reliability of using

  10. Judgement bias in goats (Capra hircus: investigating the effects of human grooming

    Directory of Open Access Journals (Sweden)

    Luigi Baciadonna

    2016-10-01

    Full Text Available Animal emotional states can be investigated by evaluating their impact on cognitive processes. In this study, we used a judgement bias paradigm to determine if short-term positive human-animal interaction (grooming induced a positive affective state in goats. We tested two groups of goats and trained them to discriminate between a rewarded and a non-rewarded location over nine training days. During training, the experimental group (n = 9 was gently groomed by brushing their heads and backs for five min over 11 days (nine training days, plus two testing days, total time 55 min. During training, the control group (n = 10 did not experience any direct interaction with the experimenter, but was kept unconstrained next to him for the same period of time. After successful completion of the training, the responses (latency time of the two groups to reach ambiguous locations situated between the two reference locations (i.e., rewarded/non-rewarded were compared over two days of testing. There was not a positive bias effect after the animals had been groomed. In a second experiment, 10 goats were tested to investigate whether grooming induced changes in physiological activation (i.e., heart rate and heart rate variability. Heart rate increased when goats were groomed compared to the baseline condition, when the same goats did not receive any contact with the experimenter. Also, subjects did not move away from the experimenter, suggesting that the grooming was positively accepted. The very good care and the regular positive contacts that goats received from humans at the study site could potentially account for the results obtained. Good husbandry outcomes are influenced by animals’ perception of the events and this is based on current circumstances, past experiences and individual variables. Taking into account animals’ individual characteristics and identifying effective strategies to induce positive emotions could increase the understanding and

  11. Transcription-induced mutational strand bias and its effect on substitution rates in human genes.

    Science.gov (United States)

    Mugal, Carina F; von Grünberg, Hans-Hennig; Peifer, Martin

    2009-01-01

    If substitution rates are not the same on the two complementary DNA strands, a substitution is considered strand asymmetric. Such substitutional strand asymmetries are determined here for the three most frequent types of substitution on the human genome (C --> T, A --> G, and G --> T). Substitution rate differences between both strands are estimated for 4,590 human genes by aligning all repeats occurring within the introns with their ancestral consensus sequences. For 1,630 of these genes, both coding strand and noncoding strand rates could be compared with rates in gene-flanking regions. All three rates considered are found to be on average higher on the coding strand and lower on the transcribed strand in comparison to their values in the gene-flanking regions. This finding points to the simultaneous action of rate-increasing effects on the coding strand--such as increased adenine and cytosine deamination--and transcription-coupled repair as a rate-reducing effect on the transcribed strand. The common behavior of the three rates leads to strong correlations of the rate asymmetries: Whenever one rate is strand biased, the other two rates are likely to show the same bias. Furthermore, we determine all three rate asymmetries as a function of time: the A --> G and G --> T rate asymmetries are both found to be constant in time, whereas the C --> T rate asymmetry shows a pronounced time dependence, an observation that explains the difference between our results and those of an earlier work by Green et al. (2003. Transcription-associated mutational asymmetry in mammalian evolution. Nat Genet. 33:514-517.). Finally, we show that in addition to transcription also the replication process biases the substitution rates in genes.

  12. Judgement bias in goats (Capra hircus): investigating the effects of human grooming

    Science.gov (United States)

    Nawroth, Christian

    2016-01-01

    Animal emotional states can be investigated by evaluating their impact on cognitive processes. In this study, we used a judgement bias paradigm to determine if short-term positive human-animal interaction (grooming) induced a positive affective state in goats. We tested two groups of goats and trained them to discriminate between a rewarded and a non-rewarded location over nine training days. During training, the experimental group (n = 9) was gently groomed by brushing their heads and backs for five min over 11 days (nine training days, plus two testing days, total time 55 min). During training, the control group (n = 10) did not experience any direct interaction with the experimenter, but was kept unconstrained next to him for the same period of time. After successful completion of the training, the responses (latency time) of the two groups to reach ambiguous locations situated between the two reference locations (i.e., rewarded/non-rewarded) were compared over two days of testing. There was not a positive bias effect after the animals had been groomed. In a second experiment, 10 goats were tested to investigate whether grooming induced changes in physiological activation (i.e., heart rate and heart rate variability). Heart rate increased when goats were groomed compared to the baseline condition, when the same goats did not receive any contact with the experimenter. Also, subjects did not move away from the experimenter, suggesting that the grooming was positively accepted. The very good care and the regular positive contacts that goats received from humans at the study site could potentially account for the results obtained. Good husbandry outcomes are influenced by animals’ perception of the events and this is based on current circumstances, past experiences and individual variables. Taking into account animals’ individual characteristics and identifying effective strategies to induce positive emotions could increase the understanding and reliability of

  13. Nonlinear cosmological consistency relations and effective matter stresses

    Energy Technology Data Exchange (ETDEWEB)

    Ballesteros, Guillermo [Museo Storico della Fisica e Centro Studi e Ricerche ' ' Enrico Fermi' ' , Piazza del Viminale 1, I-00184 Rome (Italy); Hollenstein, Lukas; Jain, Rajeev Kumar; Kunz, Martin, E-mail: guillermo.ballesteros@pd.infn.it, E-mail: lukas.hollenstein@unige.ch, E-mail: rajeev.jain@unige.ch, E-mail: martin.kunz@unige.ch [Département de Physique Théorique and Center for Astroparticle Physics, Université de Genève, Quai E. Ansermet 24, CH-1211 Genève 4 (Switzerland)

    2012-05-01

    We propose a fully nonlinear framework to construct consistency relations for testing generic cosmological scenarios using the evolution of large scale structure. It is based on the covariant approach in combination with a frame that is purely given by the metric, the normal frame. As an example, we apply this framework to the ΛCDM model, by extending the usual first order conditions on the metric potentials to second order, where the two potentials start to differ from each other. We argue that working in the normal frame is not only a practical choice but also helps with the physical interpretation of nonlinear dynamics. In this frame, effective pressures and anisotropic stresses appear at second order in perturbation theory, even for ''pressureless'' dust. We quantify their effect and compare them, for illustration, to the pressure of a generic clustering dark energy fluid and the anisotropic stress in the DGP model. Besides, we also discuss the effect of a mismatch of the potentials on the determination of galaxy bias.

  14. Source Credibility and the Biasing Effect of Narrative Information on the Perception of Vaccination Risks.

    Science.gov (United States)

    Haase, Niels; Betsch, Cornelia; Renkewitz, Frank

    2015-08-01

    Immunization rates are below the Global Immunization Vision and Strategy established by the World Health Organization. One reason for this are anti-vaccination activists, who use the Internet to disseminate their agenda, frequently by publishing narrative reports about alleged vaccine adverse events. In health communication, the use of narrative information has been shown to be effectively persuasive. Furthermore, persuasion research indicates that the credibility of an information source may serve as a cue to discount or augment the communicated message. Thus, the present study investigated the effect of source credibility on the biasing effect of narrative information regarding the perception of vaccination risks. 265 participants were provided with statistical information (20%) regarding the occurrence of vaccine adverse events after vaccination against a fictitious disease. This was followed by 20 personalized narratives from an online forum on vaccination experiences. The authors varied the relative frequency of narratives reporting vaccine adverse events (35% vs. 85%), narrative source credibility (anti-vaccination website vs. neutral health forum), and the credibility of the statistical information (reliable data vs. unreliable data vs. control) in a between-subjects design. Results showed a stable narrative bias on risk perception that was not affected by credibility cues. However, narratives from an anti-vaccination website generally led to lower perceptions of vaccination risks.

  15. Suppression of exchange bias effect in maghemite nanoparticles functionalized with H2Y

    Science.gov (United States)

    Guivar, Juan A. Ramos; Morales, M. A.; Litterst, F. Jochen

    2016-12-01

    The structural, vibrational, morphological and magnetic properties of maghemite (γ-Fe2O3) nanoparticles functionalized with polar molecules EDTA(or H4Y) and H2Y are reported. The samples were functionalized before and after total synthesis of γ-Fe2O3 nanoparticles. The molecules are anchored on the monodentate mode on the nanoparticles surface. Transmission electron microscopy (TEM) revealed the formation of maghemite nanoparticles with small diameter of 4 nm for the sample functionalized upon synthesis and 7.6 and 6.9 nm for the samples functionalized with EDTA and H2Y after the formation of nanoparticles. Exchange bias phenomena were observed in some of the samples functionalized with EDTA at temperatures below 70 K. The presence of the bias effect was discussed in terms of the formation of a thin layer of a secondary phase like lepidocrocite, and the absence of this effect was explained in terms of the chemisorption of carboxylic groups from EDTA which suppressed the canting. Studies of Mössbauer spectroscopy as a function of temperature showed slow relaxation effects and allowed discussion of the secondary phase. In the M-T curves a maximum around 116 K was associated with this secondary phase also in agreement with the Mössbauer studies. The dynamic properties were studied by AC susceptibility, the out of phase signal revealed a spin glass like regime below 36.5 K.

  16. Understanding gender bias in face recognition: effects of divided attention at encoding.

    Science.gov (United States)

    Palmer, Matthew A; Brewer, Neil; Horry, Ruth

    2013-03-01

    Prior research has demonstrated a female own-gender bias in face recognition, with females better at recognizing female faces than male faces. We explored the basis for this effect by examining the effect of divided attention during encoding on females' and males' recognition of female and male faces. For female participants, divided attention impaired recognition performance for female faces to a greater extent than male faces in a face recognition paradigm (Study 1; N=113) and an eyewitness identification paradigm (Study 2; N=502). Analysis of remember-know judgments (Study 2) indicated that divided attention at encoding selectively reduced female participants' recollection of female faces at test. For male participants, divided attention selectively reduced recognition performance (and recollection) for male stimuli in Study 2, but had similar effects on recognition of male and female faces in Study 1. Overall, the results suggest that attention at encoding contributes to the female own-gender bias by facilitating the later recollection of female faces.

  17. Practical investigation of the gate bias effect on the reverse recovery behavior of the body diode in power MOSFETs

    DEFF Research Database (Denmark)

    Lindberg-Poulsen, Kristian; Petersen, Lars Press; Ouyang, Ziwei

    2014-01-01

    This work considers an alternative method of reducing the body diode reverse recovery by taking advantage of the MOSFET body effect, and applying a bias voltage to the gate before reverse recovery. A test method is presented, allowing the accurate measurement of voltage and current waveforms during...... reverse recovery at high di=dt. Different bias voltages and dead times are combined, giving a loss map which makes it possible to evaluate the practical efficacy of gate bias on reducing the MOSFET body diode reverse recovery, while comparing it to the well known methods of dead time optimization...

  18. A Meta-Analysis of the Effect of Cognitive Bias Modification on Anxiety and Depression

    Science.gov (United States)

    Hallion, Lauren S.; Ruscio, Ayelet Meron

    2011-01-01

    Cognitive biases have been theorized to play a critical role in the onset and maintenance of anxiety and depression. Cognitive bias modification (CBM), an experimental paradigm that uses training to induce maladaptive or adaptive cognitive biases, was developed to test these causal models. Although CBM has generated considerable interest in the…

  19. The SDT Model of Belief Bias: Complexity, Time, and Cognitive Ability Mediate the Effects of Believability

    Science.gov (United States)

    Trippas, Dries; Handley, Simon J.; Verde, Michael F.

    2013-01-01

    When people evaluate conclusions, they are often influenced by prior beliefs. Prevalent theories claim that "belief bias" affects the quality of syllogistic reasoning. However, recent work by Dube, Rotello, and Heit (2010) has suggested that belief bias may be a simple response bias. In Experiment 1, receiver operating characteristic…

  20. Effect of biased feedback on motor imagery learning in BCI-teleoperation system

    Directory of Open Access Journals (Sweden)

    Maryam eAlimardani

    2014-04-01

    Full Text Available Feedback design is an important issue in motor imagery BCI systems. Regardless, to date it has not been reported how feedback presentation can optimize co-adaptation between a human brain and such systems. This paper assesses the effect of realistic visual feedback on users’ BC performance and motor imagery skills. We previously developed a tele-operation system for a pair of humanlike robotic hands and showed that BCI control of such hands along with first-person perspective visual feedback of movements can arouse a sense of embodiment in the operators. In the first stage of this study, we found that the intensity of this ownership illusion was associated with feedback presentation and subjects’ performance during BCI motion control. In the second stage, we probed the effect of positive and negative feedback bias on subjects’ BCI performance and motor imagery skills. Although the subject specific classifier, which was set up at the beginning of experiment, detected no significant change in the subjects’ online performance, evaluation of brain activity patterns revealed that subjects’ self-regulation of motor imagery features improved due to a positive bias of feedback and a possible occurrence of ownership illusion. Our findings suggest that in general training protocols for BCIs, manipulation of feedback can play an important role in the optimization of subjects’ motor imagery skills.

  1. Defending or Challenging the Status Quo: Position Effects on Biased Intergroup Perceptions

    Directory of Open Access Journals (Sweden)

    Emma A. Bäck

    2014-05-01

    Full Text Available The default ideological position is status quo maintaining, and challenging the status quo is associated with increased efforts and risks. Nonetheless, some people choose to challenge the status quo. Therefore, to challenge the status quo should imply a strong belief in one’s position as the correct one, and thus efforts may be undertaken to undermine the position of others. Study 1 (N = 311 showed that challengers undermined, by ascribing more externality and less rationality, the position of defenders to a larger extent than defenders did of challengers’ position. Studies 2 (N = 135 and 3 (N = 109 tested if these effects were driven by the implied minority status of the challenging position. Results revealed no effects of experimentally manipulated numerical status, but challengers were again more biased than defenders. Study 3 also revealed that challengers felt more negatively toward their opponents (possibly due to greater social identification with like-minded others, and these negative emotions in turn predicted biased attributions. Results are important as they add to the understanding of how intergroup conflict may arise, providing explanations for why challengers are less tolerant of others’ point of view.

  2. Photomultiplier tube calibration based on Na lidar observation and its effect on heat flux bias.

    Science.gov (United States)

    Liu, Alan Z; Guo, Yafang

    2016-11-20

    Na lidar can measure vertical wind and temperature at high temporal and vertical resolutions, enough to resolve gravity wave perturbations. Heat flux due to dissipating gravity waves is an important quantity that can be derived from such perturbations. When lidar signals are high, a photomultiplier tube (PMT) used to count incoming photons may suffer from the saturation effect, and its output count is not linearly related to incoming photon counts. Corrections to this effect can be measured in a laboratory setting but may have large errors at high count rates. We show that the errors in the PMT correction can cause significant bias in the heat flux calculation due to the inherent correlation between wind and temperature errors. Using the measurements made by Na lidar at the Andes Lidar Observatory with Hamamatsu PMTs, we developed a calibration procedure to remove such PMT correction errors from laboratory measurements. By applying the revised PMT correction curve we demonstrated that the heat flux bias can be removed through this procedure.

  3. Effect of a direct current bias on the electrohydrodynamic performance of a surface dielectric barrier discharge actuator for airflow control

    Science.gov (United States)

    Yan, Huijie; Yang, Liang; Qi, Xiaohua; Ren, Chunsheng

    2015-02-01

    The effect of a DC bias on the electrohydrodynamics (EHD) force induced by a surface dielectric barrier AC discharge actuator for airflow control at the atmospheric pressure is investigated. The measurement of the surface potential due to charge deposition at different DC biases is carried out by using a special designed corona like discharge potential probe. From the surface potential data, the plasma electromotive force is shown not affected much by the DC biases except for some reduction of the DC bias near the exposed electrode edge for the sheath-like configuration. The total thrust is measured by an analytical balance, and an almost linear relationship to the potential voltage at the exposed electrode edge is found for the direct thrust force. The temporally averaged ionic wind characteristics are investigated by Pitot tube sensor and schlieren visualization system. It is found that the ionic wind velocity profiles with different DC biases are almost the same in the AC discharge plasma area but gradually diversified in the further downstream area as well as the upper space away from the discharge plasma area. Also, the DC bias can significantly modify the topology of the ionic wind produced by the AC discharge actuator. These results can provide an insight into how the DC biases to affect the force generation.

  4. The generalizability of gender bias: Testing the effects of contextual, explicit, and implicit sexism on labor arbitration decisions.

    Science.gov (United States)

    Girvan, Erik J; Deason, Grace; Borgida, Eugene

    2015-10-01

    Decades of social-psychological research show that gender bias can result from features of the social context and from individual-level psychological predispositions. Do these sources of bias impact legal decisions, which are frequently made by people subject to factors that have been proposed to reduce bias (training and accountability)? To answer the question, we examined the potential for 3 major social-psychological theories of gender bias (role-congruity theory, ambivalent sexism, and implicit bias) to predict outcomes of labor arbitration decisions. In the first study, undergraduate students and professional arbitrators made decisions about 2 mock arbitration cases in which the gender of the employee-grievants was experimentally manipulated. Student participants' decisions showed the predicted gender bias, whereas the decisions of experienced professionals did not. Individual-level attitudes did not predict the extent of the observed bias and accountability did not attenuate it. In the second study, arbitrators' explicit and implicit gender attitudes were significant predictors of their decisions in published cases. The laboratory and field results suggest that context, expertise, and implicit and explicit attitudes are relevant to legal decision-making, but that laboratory experiments alone may not fully capture the nature of their effect on legal professionals' decisions in real cases.

  5. Effects of drain bias on the statistical variation of double-gate tunnel field-effect transistors

    Science.gov (United States)

    Choi, Woo Young

    2017-04-01

    The effects of drain bias on the statistical variation of double-gate (DG) tunnel field-effect transistors (TFETs) are discussed in comparison with DG metal–oxide–semiconductor FETs (MOSFETs). Statistical variation corresponds to the variation of threshold voltage (V th), subthreshold swing (SS), and drain-induced barrier thinning (DIBT). The unique statistical variation characteristics of DG TFETs and DG MOSFETs with the variation of drain bias are analyzed by using full three-dimensional technology computer-aided design (TCAD) simulation in terms of the three dominant variation sources: line-edge roughness (LER), random dopant fluctuation (RDF) and workfunction variation (WFV). It is observed than DG TFETs suffer from less severe statistical variation as drain voltage increases unlike DG MOSFETs.

  6. Effect of Bias Step on the I-V Curve in Double-Barrier AlGaAs/GaAs/AlGaAs Resonant-Tunnelling Devices

    Institute of Scientific and Technical Information of China (English)

    DAI Zhen-Hong; NI Jun

    2006-01-01

    @@ We investigate the non-equilibrium electron transport properties of double-barrier AlGaAs/GaAs/AlGaAs resonanttunnelling devices in nonlinear bias using the time-dependent simulation technique. It is found that the bias step of the external bias voltage applied on the device has an important effect on the final current-voltage (I - V) curves. The results show that different bias step applied on the device can change the bistability, hysteresis and current plateau structure of the I - V curve. The current plateau occurs only in the case of small bias step. As the bias step increases, this plateau structure disappears.

  7. Effect of substrate bias in nitrogen incorporated amorphous carbon films with embedded nanoparticles deposited by filtered cathodic jet carbon arc technique

    Energy Technology Data Exchange (ETDEWEB)

    Panwar, O.S., E-mail: ospanwar@mail.nplindia.ernet.in [Amorphous and Microcrystalline Silicon Solar Cell Group, Physics of Energy Harvesting Division, National Physical Laboratory (C.S.I.R.), Dr. K.S. Krishnan Road, New Delhi-110012 (India); Kumar, Sushil; Ishpal,; Srivastava, A.K.; Chouksey, Abhilasha; Tripathi, R.K.; Basu, A. [Amorphous and Microcrystalline Silicon Solar Cell Group, Physics of Energy Harvesting Division, National Physical Laboratory (C.S.I.R.), Dr. K.S. Krishnan Road, New Delhi-110012 (India)

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer a-C: N films having nanoparticles were deposited by filtered cathodic jet carbon arc (FCJCA) technique. Black-Right-Pointing-Pointer The effect of negative substrate bias on the properties of a-C: N films embedded with nanoparticles have been studied. Black-Right-Pointing-Pointer The properties of a-C: N films deposited by FCJCA technique have been compared with ta-C: N films deposited by FCVA process. - Abstract: The properties of nitrogen incorporated amorphous carbon (a-C: N) films with embedded nanoparticles, deposited using a filtered cathodic jet carbon arc technique, are reported. X-ray diffraction, high resolution transmission electron microscope and Raman spectroscopy measurements reveal an amorphous structure, but on closer examination the presence of clusters of nanocarbon single crystals with d-spacing close to diamond cubic-phase have also been identified. The effect of substrate bias on the microstructure, conductivity, activation energy, optical band gap, optical constants, residual stress, hardness, elastic modulus, plastic index parameter, percentage elastic recovery and density of states of a-C: N films have been studied and the properties obtained are found to depend on the substrate bias.

  8. Effect of Bias Correction of Satellite-Rainfall Estimates on Runoff Simulations at the Source of the Upper Blue Nile

    Directory of Open Access Journals (Sweden)

    Emad Habib

    2014-07-01

    Full Text Available Results of numerous evaluation studies indicated that satellite-rainfall products are contaminated with significant systematic and random errors. Therefore, such products may require refinement and correction before being used for hydrologic applications. In the present study, we explore a rainfall-runoff modeling application using the Climate Prediction Center-MORPHing (CMORPH satellite rainfall product. The study area is the Gilgel Abbay catchment situated at the source basin of the Upper Blue Nile basin in Ethiopia, Eastern Africa. Rain gauge networks in such area are typically sparse. We examine different bias correction schemes applied locally to the CMORPH product. These schemes vary in the degree to which spatial and temporal variability in the CMORPH bias fields are accounted for. Three schemes are tested: space and time-invariant, time-variant and spatially invariant, and space and time variant. Bias-corrected CMORPH products were used to calibrate and drive the Hydrologiska Byråns Vattenbalansavdelning (HBV rainfall-runoff model. Applying the space and time-fixed bias correction scheme resulted in slight improvement of the CMORPH-driven runoff simulations, but in some instances caused deterioration. Accounting for temporal variation in the bias reduced the rainfall bias by up to 50%. Additional improvements were observed when both the spatial and temporal variability in the bias was accounted for. The rainfall bias was found to have a pronounced effect on model calibration. The calibrated model parameters changed significantly when using rainfall input from gauges alone, uncorrected, and bias-corrected CMORPH estimates. Changes of up to 81% were obtained for model parameters controlling the stream flow volume.

  9. Impact of Scale Dependent Bias and Nonlinear Structure Growth on the ISW Effect: Angular Power Spectra

    CERN Document Server

    Smith, Robert E; Seljak, Uros

    2009-01-01

    We investigate the impact of nonlinear evolution of the gravitational potentials in the LCDM model on the Integrated Sachs-Wolfe (ISW) contribution to the CMB temperature power spectrum, and on the cross-power spectrum of the CMB and a set of biased tracers of the mass. We use an ensemble of N-body simulations to directly follow the potentials and compare results to perturbation theory (PT). The predictions from PT match the results to high precision for k100 the departures are more significant, however the CMB signal is more than a factor 10^3 larger at this scale. Nonlinear ISW effects therefore play no role in shaping the CMB power spectrum for l<1500. We analyze the CMB--density tracer cross-spectrum using simulations and renormalized bias PT, and find good agreement. The usual assumption is that nonlinear evolution enhances the growth of structure and counteracts linear ISW on small scales, leading to a change in sign of the CMB-LSS cross-spectrum at small scales. However, PT analysis suggests that th...

  10. Experience of automation failures in training: effects on trust, automation bias, complacency and performance.

    Science.gov (United States)

    Sauer, Juergen; Chavaillaz, Alain; Wastell, David

    2016-06-01

    This work examined the effects of operators' exposure to various types of automation failures in training. Forty-five participants were trained for 3.5 h on a simulated process control environment. During training, participants either experienced a fully reliable, automatic fault repair facility (i.e. faults detected and correctly diagnosed), a misdiagnosis-prone one (i.e. faults detected but not correctly diagnosed) or a miss-prone one (i.e. faults not detected). One week after training, participants were tested for 3 h, experiencing two types of automation failures (misdiagnosis, miss). The results showed that automation bias was very high when operators trained on miss-prone automation encountered a failure of the diagnostic system. Operator errors resulting from automation bias were much higher when automation misdiagnosed a fault than when it missed one. Differences in trust levels that were instilled by the different training experiences disappeared during the testing session. Practitioner Summary: The experience of automation failures during training has some consequences. A greater potential for operator errors may be expected when an automatic system failed to diagnose a fault than when it failed to detect one.

  11. Effect of substrate bias on deposition behaviour of charged silicon nanoparticles in ICP-CVD process

    Science.gov (United States)

    Yoo, Seung-Wan; You, Shin-Jae; Kim, Jung-Hyung; Seong, Dae-Jin; Seo, Byong-Hoon; Hwang, Nong-Moon

    2017-01-01

    The effect of a substrate bias on the deposition behaviour of crystalline silicon films during inductively coupled plasma chemical vapour deposition (ICP-CVD) was analysed by consideration of non-classical crystallization, in which the building block is a nanoparticle rather than an individual atom or molecule. The coexistence of positively and negatively charged nanoparticles in the plasma and their role in Si film deposition are confirmed by applying bias voltages to the substrate, which is sufficiently small as not to affect the plasma potential. The sizes of positively and negatively charged nanoparticles captured on a carbon membrane and imaged using TEM are, respectively, 2.7-5.5 nm and 6-13 nm. The film deposited by positively charged nanoparticles has a typical columnar structure. In contrast, the film deposited by negatively charged nanoparticles has a structure like a powdery compact with the deposition rate about three times higher than that for positively charged nanoparticles. All the films exhibit crystallinity even though the substrate is at room temperature, which is attributed to the deposition of crystalline nanoparticles formed in the plasma. The film deposited by negatively charged nanoparticles has the highest crystalline fraction of 0.84.

  12. The effects of social evaluation and looming threat on self-attentional biases and social anxiety.

    Science.gov (United States)

    Haikal, Muhammad; Hong, Ryan Y

    2010-04-01

    This paper examines how two proposed cognitive vulnerabilities of social anxiety, the fear of negative evaluation, and looming cognitive style may combine with socially demanding situations in predicting social anxiety symptoms and performance deficits. Fifty-two individuals previously identified as possessing these two cognitive vulnerabilities were randomly assigned to conditions in a 2 (high versus low social evaluation)x2 (high versus low temporal looming) experimental design. Significant interaction effects were found for: (a) residual change in anxiety symptoms from baseline level, and (b) performance on a speech task. Specifically, cognitively at-risk individuals exhibited the most increase in anxiety and the most performance deficits in the condition where social evaluation and temporal looming were high. In addition, a mediational effect of illusion of transparency (a form of self-attentional bias) between situational demands and residual change in anxiety was found. Implications arising from these results are discussed.

  13. The foreign-language effect: thinking in a foreign tongue reduces decision biases.

    Science.gov (United States)

    Keysar, Boaz; Hayakawa, Sayuri L; An, Sun Gyu

    2012-06-01

    Would you make the same decisions in a foreign language as you would in your native tongue? It may be intuitive that people would make the same choices regardless of the language they are using, or that the difficulty of using a foreign language would make decisions less systematic. We discovered, however, that the opposite is true: Using a foreign language reduces decision-making biases. Four experiments show that the framing effect disappears when choices are presented in a foreign tongue. Whereas people were risk averse for gains and risk seeking for losses when choices were presented in their native tongue, they were not influenced by this framing manipulation in a foreign language. Two additional experiments show that using a foreign language reduces loss aversion, increasing the acceptance of both hypothetical and real bets with positive expected value. We propose that these effects arise because a foreign language provides greater cognitive and emotional distance than a native tongue does.

  14. Greater physiological and behavioral effects of interrupted stress pattern compared to daily restraint stress in rats.

    Directory of Open Access Journals (Sweden)

    Wei Zhang

    Full Text Available Repeated stress can trigger a range of psychiatric disorders, including anxiety. The propensity to develop abnormal behaviors after repeated stress is related to the severity, frequency and number of stressors. However, the pattern of stress exposure may contribute to the impact of stress. In addition, the anxiogenic nature of repeated stress exposure can be moderated by the degree of coping that occurs, and can be reflected in homotypic habituation to the repeated stress. However, expectations are not clear when a pattern of stress presentation is utilized that diminishes habituation. The purpose of these experiments is to test whether interrupted stress exposure decreases homotypic habituation and leads to greater effects on anxiety-like behavior in adult male rats. We found that repeated interrupted restraint stress resulted in less overall homotypic habituation compared to repeated daily restraint stress. This was demonstrated by greater production of fecal boli and greater corticosterone response to restraint. Furthermore, interrupted restraint stress resulted in a lower body weight and greater adrenal gland weight than daily restraint stress, and greater anxiety-like behavior in the elevated plus maze. Control experiments demonstrated that these effects of the interrupted pattern could not be explained by differences in the total number of stress exposures, differences in the total number of days that the stress periods encompased, nor could it be explained as a result of only the stress exposures after an interruption from stress. These experiments demonstrate that the pattern of stress exposure is a significant determinant of the effects of repeated stress, and that interrupted stress exposure that decreases habituation can have larger effects than a greater number of daily stress exposures. Differences in the pattern of stress exposure are therefore an important factor to consider when predicting the severity of the effects of repeated

  15. Intergroup biases of the intermediate-status group: the effect of stability and instability of social stratification.

    Science.gov (United States)

    Caricati, Luca; Monacelli, Nadia

    2012-01-01

    In two studies, the effect of instability of social stratification on intergroup behaviour of the intermediate-status group was investigated. In both studies, participants were categorised in the intermediate-status group. In Study 1, perceived instability was measured. Results show that the more social stratification was perceived as stable, the more intermediate-status group members were biased against the high-status group. Biases against both high- and low-status groups tended to become similar as social stratification was perceived as more unstable. In Study 2, instability was manipulated in upward and downward conditions. Results showed that, in the upwardly unstable condition, intermediate-status group members were more biased against high-status group, while in the downwardly unstable condition they were more biased against the low-status group.

  16. Intergroup bias.

    Science.gov (United States)

    Hewstone, Miles; Rubin, Mark; Willis, Hazel

    2002-01-01

    This chapter reviews the extensive literature on bias in favor of in-groups at the expense of out-groups. We focus on five issues and identify areas for future research: (a) measurement and conceptual issues (especially in-group favoritism vs. out-group derogation, and explicit vs. implicit measures of bias); (b) modern theories of bias highlighting motivational explanations (social identity, optimal distinctiveness, uncertainty reduction, social dominance, terror management); (c) key moderators of bias, especially those that exacerbate bias (identification, group size, status and power, threat, positive-negative asymmetry, personality and individual differences); (d) reduction of bias (individual vs. intergroup approaches, especially models of social categorization); and (e) the link between intergroup bias and more corrosive forms of social hostility.

  17. Evaluating vegetation effects on animal demographics: the role of plant phenology and sampling bias.

    Science.gov (United States)

    Gibson, Daniel; Blomberg, Erik J; Sedinger, James S

    2016-04-24

    Plant phenological processes produce temporal variation in the height and cover of vegetation. Key aspects of animal life cycles, such as reproduction, often coincide with the growing season and therefore may inherently covary with plant growth. When evaluating the influence of vegetation variables on demographic rates, the decision about when to measure vegetation relative to the timing of demographic events is important to avoid confounding between the demographic rate of interest and vegetation covariates. Such confounding could bias estimated effect sizes or produce results that are entirely spurious. We investigated how the timing of vegetation sampling affected the modeled relationship between vegetation structure and nest survival of greater sage-grouse (Centrocercus urophasianus), using both simulated and observational data. We used the height of live grasses surrounding nests as an explanatory covariate, and analyzed its effect on daily nest survival. We compared results between models that included grass height measured at the time of nest fate (hatch or failure) with models where grass height was measured on a standardized date - that of predicted hatch date. Parameters linking grass height to nest survival based on measurements at nest fate produced more competitive models, but slope coefficients of grass height effects were biased high relative to truth in simulated scenarios. In contrast, measurements taken at predicted hatch date accurately predicted the influence of grass height on nest survival. Observational data produced similar results. Our results demonstrate the importance of properly considering confounding between demographic traits and plant phenology. Not doing so can produce results that are plausible, but ultimately inaccurate.

  18. Stress distribution and effective stress intensity factor of a blunt crack after dislocation emission

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The stress fields induced by a dislocation and its image dislocations around a narrow elliptic void are formulated. Based on the solution, the stress distribution and effective stress intensity factor of a blunt (elliptic) crack were calculated under mode I constant loading. The results show that a dislocation-free zone (DFZ) is formed after dislocation emission. There exists a second stress peak in the DFZ except a stress peak at the blunt crack tip. With an increase in the applied stress intensity factor KIa or the friction stress τf of the material, the DFZ size and the peak stress at the crack tip decrease, but the peak stress in the DFZ and the effective stress intensity factor KIf presiding at the crack tip increase. Because of dislocation shielding effects, shielding ratio KIa/KIf increases with increasing KIa}, but it decreases with increasing τf.

  19. Stress distribution and effective stress intensity factor of a blunt crack after dislocation emission

    Institute of Scientific and Technical Information of China (English)

    钱才富; 乔利杰; 褚武扬

    2000-01-01

    The stress fields induced by a dislocation and its image dislocations around a narrow elliptic void are formulated. Based on the solution, the stress distribution and effective stress intensity factor of a blunt (elliptic) crack were calculated under mode I constant loading. The results show that a dislocation-free zone (DFZ) is formed after dislocation emission. There exists a second stress peak in the DFZ except a stress peak at the blunt crack tip. With an increase in the applied stress intensity factor Kla or the friction stress T, of the material, the DFZ size and the peak stress at the crack tip decrease, but the peak stress in the DFZ and the effective stress intensity factor Klf presiding at the crack tip increase. Because of dislocation shielding effects, shielding ratio Kla/Klf increases with increasing Kla, but it decreases with increasing Tf.

  20. Age biases in face processing: the effects of experience across development.

    Science.gov (United States)

    Macchi Cassia, Viola

    2011-11-01

    In this paper, I review studies investigating discrimination and recognition abilities for faces of different ages in children and adults. Contrary to the earlier assertion that own-age faces are better recognized than other-age faces (own-age bias; OAB), I discuss recent evidence for a processing advantage for adult versus non-adult faces. This evidence is interpreted as suggesting that the precocious and continuous exposure to adult faces may shape the individual's face representation across development. Moreover, by testing how experience with faces of various ages acquired at different times in development modulates face-processing skills, this evidence shows that plasticity of face recognition abilities decreases with age, but early-acquired experience has enduring effects that impact our ability to learn from encounters with new types of faces in adulthood.

  1. Stress Matters: Effects of Anticipated Lexical Stress on Silent Reading

    Science.gov (United States)

    Breen, Mara; Clifton, Charles, Jr.

    2011-01-01

    This paper presents findings from two eye-tracking studies designed to investigate the role of metrical prosody in silent reading. In Experiment 1, participants read stress-alternating noun-verb or noun-adjective homographs (e.g. "PREsent", "preSENT") embedded in limericks, such that the lexical stress of the homograph, as determined by context,…

  2. Stress effects in twisted highly birefringent fibers

    Science.gov (United States)

    Wolinski, Tomasz R.

    1994-03-01

    Hydrostatic pressure and uniaxial longitudinal strain effects in twisted highly birefringent optical fibers have been investigated from the point of the Marcuse mode-coupling theory. The problem is analyzed in terms of local normal modes of the ideal fiber and in the limit of weak twist, where large linear birefringence dominates over twist effect, and therefore twist coupling between local modes is not effective. The authors present the results of birefringence measurements in highly birefringent bow-tie fibers influenced simultaneously by hydrostatic pressure up to 100 MPa and twisting the result for highly birefringent elliptical-core fibers influenced by uniaxial longitudinal strain up to 4000 (mu) (epsilon) and twisting effect. The birefringence measurement method is based on twist-induced effects and has been successfully applied in a stress environment. The experiment was conducted with a specially designed stress generating device that makes it possible to simultaneously generate various mechanical perturbations such as hydrostatic and radial pressure, axial strain and twist, allowing study of their influence on mode propagation in optical fibers. A comparison with theoretical results as well as with pervious experimental data on stress influence on the beat length parameter in highly birefringent fibers is also provided.

  3. On commercial media bias

    OpenAIRE

    Germano, Fabrizio

    2008-01-01

    Within the spokes model of Chen and Riordan (2007) that allows for non-localized competition among arbitrary numbers of media outlets, we quantify the effect of concentration of ownership on quality and bias of media content. A main result shows that too few commercial outlets, or better, too few separate owners of commercial outlets can lead to substantial bias in equilibrium. Increasing the number of outlets (commercial and non-commercial) tends to bring down this bias; but the strongest ef...

  4. Studies on effect of stress preconditioning in restrain stress-induced behavioral alterations.

    Science.gov (United States)

    Kaur, Rajneet; Jaggi, Amteshwar Singh; Singh, Nirmal

    2010-02-01

    Stress preconditioning has been documented to confer on gastroprotective effects on stress-induced gastric ulcerations. However, the effects of prior exposure of stress preconditioning episodes on stress-induced behavioral changes have not been explored yet. Therefore the present study was designed to investigate the ameliorative effects of stress preconditioning in immobilization stress-induced behavioral alterations in rats. The rats were subjected to restrain stress by placing in restrainer (5.5 cm in diameter and 18 cm in length) for 3.5 h. Stress preconditioning was induced by subjecting the rats to two cycles of restraint and restrain-free periods of 15 min each. Furthermore, a similar type of stress preconditioning was induced using different time cycles of 30 and 45 min. The extent and severity of the stress-induced behavioral alterations were assessed using different behavioral tests such as hole-board test, social interaction test, open field test, and actophotometer. Restrain stress resulted in decrease in locomotor activity, frequency of head dips and rearing in hole board, line crossing and rearing in open field, and decreased following and increased avoidance in social interaction test. Stress preconditioning with two cycles of 15, 30 or 45 min respectively, did not attenuate stress-induced behavioral changes to any extent. It may be concluded that stress preconditioning does not seem to confer any protective effect in modulating restrain stress-induced behavioral alterations.

  5. Bias, Accuracy, and Impact of Indirect Genetic Effects in Infectious Diseases

    Science.gov (United States)

    Lipschutz-Powell, Debby; Woolliams, J. A.; Bijma, P.; Pong-Wong, R.; Bermingham, M. L.; Doeschl-Wilson, A. B.

    2012-01-01

    Selection for improved host response to infectious disease offers a desirable alternative to chemical treatment but has proven difficult in practice, due to low heritability estimates of disease traits. Disease data from field studies is often binary, indicating whether an individual has become infected or not following exposure to an infectious disease. Numerous studies have shown that from this data one can infer genetic variation in individuals’ underlying susceptibility. In a previous study, we showed that with an indirect genetic effect (IGE) model it is possible to capture some genetic variation in infectivity, if present, as well as in susceptibility. Infectivity is the propensity of transmitting infection upon contact with a susceptible individual. It is an important factor determining the severity of an epidemic. However, there are severe shortcomings with the Standard IGE models as they do not accommodate the dynamic nature of disease data. Here we adjust the Standard IGE model to (1) make expression of infectivity dependent on the individuals’ disease status (Case Model) and (2) to include timing of infection (Case-ordered Model). The models are evaluated by comparing impact of selection, bias, and accuracy of each model using simulated binary disease data. These were generated for populations with known variation in susceptibility and infectivity thus allowing comparisons between estimated and true breeding values. Overall the Case Model provided better estimates for host genetic susceptibility and infectivity compared to the Standard Model in terms of bias, impact, and accuracy. Furthermore, these estimates were strongly influenced by epidemiological characteristics. However, surprisingly, the Case-Ordered model performed considerably worse than the Standard and the Case Models, pointing toward limitations in incorporating disease dynamics into conventional variance component estimation methodology and software used in animal breeding. PMID

  6. Effects of sertraline, duloxetine, vortioxetine, and idazoxan in the rat affective bias test

    DEFF Research Database (Denmark)

    Refsgaard, Louise Konradsen; Haubro, Kia; Pickering, Darryl S

    2016-01-01

    Rationale Affective biases seemingly play a crucial role for the onset and development of depression. Acute treatment with monoamine-based antidepressants positively influence emotional processing, and an early correction of biases likely results in repeated positive experiences that ultimately l...

  7. Nonlinear excitation kinetics of biased quantum wells. Coherent dynamical screening effect

    DEFF Research Database (Denmark)

    Turchinovich, Dmitry; Jepsen, Peter Uhd

    2006-01-01

    In this paper we describe a strongly nonlinear process of ultrafast photoexcitation of a biased quantum well. This process is governed by coherent dynamical screening, where the instantaneously polarized photoexcited carriers screen initial bias field. This results in a dynamic modification...

  8. The Accuracy of Metacomprehension Judgments: The Biasing Effect of Text Order

    Science.gov (United States)

    Linderholm, Tracy; Wang, Xuesong; Therriault, David; Zhao, Qin; Jakiel, Laura

    2012-01-01

    Introduction: Two experiments tested the hypothesis that relative metacomprehension accuracy is vulnerable when readers' cognitive efforts are biased by text order. It is proposed that the difficulty level of initial text information biases readers' estimates of text comprehension but is correctable when more cognitive effort is applied. Method:…

  9. When Biased Language Use Is Associated with Bullying and Dominance Behavior: The Moderating Effect of Prejudice

    Science.gov (United States)

    Poteat, V. Paul; DiGiovanni, Craig D.

    2010-01-01

    Biased language related to sexual orientation is used frequently among students and is related to prominent social concerns such as bullying. Prejudice toward gay, lesbian, bisexual, and transgender individuals also has been examined among adolescents, but separately from these behaviors. This study tested whether biased language use was…

  10. Influence of effective stress coefficient on mechanical failure of chalk

    DEFF Research Database (Denmark)

    Alam, Mohammad Monzurul; Fabricius, Ida Lykke; Hjuler, M.L.

    2012-01-01

    , as this process could affect the grain contact cement. If this happens, the effective stress at the grain contacts in a reservoir will change according to the effective stress principle of Biot. In a p′-q space for failure analysis, we observed that a higher effective stress coefficient reduces the elastic region...... and vice versa. However, as the effective stress working on the rock decreases with increased effective stress coefficient, the reduction of elastic region will have less effect on pore collapse strength if we consider the change in the effective stress coefficient. This finding will help estimate a more......The Effective stress coefficient is a measure of how chalk grains are connected with each other. The stiffness of chalk may decrease if the amount of contact cements between the grains decreases, which may lead to an increase of the effective stress coefficient. We performed CO2 injection in chalk...

  11. Stress Management Strategies for Students: The Immediate Effects of Yoga, Humor, and Reading on Stress

    Science.gov (United States)

    Rizzolo, Denise; Zipp, Genevieve Pinto; Stiskal, Doreen; Simpkins, Susan

    2009-01-01

    Background: Health science programs can be demanding and difficult for many students, leading to high levels of stress. High levels of stress can have a negative effect on students and subsequently the practicing clinician. Research suggests that yoga, humor, and reading are simple, effective methods to help reduce stress. To date no research…

  12. Effects of bias on dynamics of an AC-driven two-electron quantum-dot molecule

    Institute of Scientific and Technical Information of China (English)

    Wang Li-Min; Duan Su-Qing; Zhao Xian-Geng; Liu Cheng-Shi

    2005-01-01

    The effects of bias on the dynamical localization of two interacting electrons in a pair of coupled quantum dots driven by external AC fields have been numerically investigated. With an effective two-site model and Floquet formalism,the time-dependent Schrodinger equation is numerically solved and the Pmin, the minimum of the population evolution of the initial state within a certain time period, is used to quantify the degree of the dynamical localization. Results indicate that the bias can change the energy of the initial state and break the dynamical symmetry of the system with a pure AC field. And the amplitude of the AC field with dynamical localization phenomenon changes with bias. All the numerical results are explained by the perturbation theory and two-level approximation.

  13. Objects in Kepler's Mirror May be Larger Than They Appear: Bias and Selection Effects in Transiting Planet Surveys

    Science.gov (United States)

    Gaidos, Eric; Mann, Andrew W.

    2013-01-01

    Statistical analyses of large surveys for transiting planets such as the Kepler mission must account for systematic errors and biases. Transit detection depends not only on the planet's radius and orbital period, but also on host star properties. Thus, a sample of stars with transiting planets may not accurately represent the target population. Moreover, targets are selected using criteria such as a limiting apparent magnitude. These selection effects, combined with uncertainties in stellar radius, lead to biases in the properties of transiting planets and their host stars. We quantify possible biases in the Kepler survey. First, Eddington bias produced by a steep planet radius distribution and uncertainties in stellar radius results in a 15%-20% overestimate of planet occurrence. Second, the magnitude limit of the Kepler target catalog induces Malmquist bias toward large, more luminous stars and underestimation of the radii of about one-third of candidate planets, especially those larger than Neptune. Third, because metal-poor stars are smaller, stars with detected planets will be very slightly (target average. Fourth, uncertainties in stellar radii produce correlated errors in planet radius and stellar irradiation. A previous finding, that highly irradiated giants are more likely to have "inflated" radii, remains significant, even accounting for this effect. In contrast, transit depth is negatively correlated with stellar metallicity even in the absence of any intrinsic correlation, and a previous claim of a negative correlation between giant planet transit depth and stellar metallicity is probably an artifact.

  14. A FIBER-BRIDGING MODEL WITH STRESS GRADIENT EFFECTS

    Institute of Scientific and Technical Information of China (English)

    孙毅; 李涛

    2000-01-01

    Institute of Mechanics, Chinese Academy of Sciences, Beijing 100080, China)ABSTRACT: A fiber-bridging model with stress gradient effects is proposed for unidirectional fiber-reinforced composites. The stress gradient terms are introduced by solving a micromechanical model under a non-uniform stress loading. It is shown that the stress gradient effect is significant on both the fiber-bridging stress distribution and the value of the critical load of fiber failure.

  15. Effect of antiferromagnetic layer thickness on exchange bias, training effect, and magnetotransport properties in ferromagnetic/antiferromagnetic antidot arrays

    Energy Technology Data Exchange (ETDEWEB)

    Gong, W. J.; Liu, W., E-mail: wliu@imr.ac.cn; Feng, J. N.; Zhang, Z. D. [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Kim, D. S.; Choi, C. J. [Functional Materials Division, Korea Institute of Materials Science, 531 Changwon- daero, Changwon 631-831 (Korea, Republic of)

    2014-04-07

    The effect of antiferromagnetic (AFM) layer on exchange bias (EB), training effect, and magnetotransport properties in ferromagnetic (FM) /AFM nanoscale antidot arrays and sheet films Ag(10 nm)/Co(8 nm)/NiO(t{sub NiO})/Ag(5 nm) at 10 K is studied. The AFM layer thickness dependence of the EB field shows a peak at t{sub NiO} = 2 nm that is explained by using the random field model. The misalignment of magnetic moments in the three-dimensional antidot arrays causes smaller decrease of EB field compared with that in the sheet films for training effect. The anomalous magnetotransport properties, in particular positive magnetoresistance (MR) for antidot arrays but negative MR for sheet films are found. The training effect and magnetotransport properties are strongly affected by the three-dimensional spin-alignment effects in the antidot arrays.

  16. Effect of high substrate bias and hydrogen and nitrogen incorporation on filtered cathodic vacuum arc deposited tetrahedral amorphous carbon films

    Energy Technology Data Exchange (ETDEWEB)

    Panwar, O.S. [Plasma Processed Materials Group, National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi-110 012 (India)], E-mail: ospanwar@mail.nplindia.ernet.in; Khan, Mohd. Alim [Plasma Processed Materials Group, National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi-110 012 (India); Kumar, Mahesh; Shivaprasad, S.M. [Surface Physics and Nanostructures Group, National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi-110 012 (India); Satyanarayana, B.S. [MIT Innovation Centre and Electronics and Communication Department, Manipal Institute of Technology, Manipal-579104 (India); Dixit, P.N. [Plasma Processed Materials Group, National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi-110 012 (India); Bhattacharyya, R. [Emeritus Scientist, National Physical Laboratory, New Delhi-110012 (India); Khan, M.Y. [Department of Physics, Jamia Millia Islamia, Central University, New Delhi-110025 (India)

    2008-02-29

    The application of a sufficiently high negative substrate bias, during the growth of tetrahedral amorphous carbon (ta-C), is usually associated with low sp{sup 3} bonding configuration and stressed films. However, in an effort to understand and utilize the higher pseudo thermo dynamical conditions during the film growth, at high negative substrate bias (- 300 V), reported here is a study on ta-C films grown under different hydrogen and nitrogen concentration. As grown ta-C films were studied under different negative substrate bias conditions. The variation of the sp{sup 3} content and sp{sup 3}/sp{sup 2} ratio in the ta-C films exhibits a trend similar to those reported in literature, with a subtle variation in this report being the substrate bias voltage, which was observed to be around - 200 V, for obtaining the highest sp{sup 3} (80%) bonding and sp{sup 3}/sp{sup 2} (3.95) ratio. The hydrogen and nitrogen incorporated ta-C films studied, at a bias of - 300 V, show an increase in sp{sup 3} (87-91%) bonding and sp{sup 3}/sp{sup 2} (7-10) ratio in the range of studies reported. The inference is drawn on the basis of the set of data obtained from measurements carried out using X-ray photoelectron spectroscopy, X-ray induced Auger electron spectroscopy and Raman spectroscopy of as grown and hydrogen and nitrogen incorporated ta-C films deposited using an S bend filtered cathodic vacuum arc system. The study indicates the possibility of further tailoring ta-C film properties and also extending capabilities of the cathodic arc system for developing carbon based films for electronics and tribological applications.

  17. Selection Bias, Vote Counting, and Money-Priming Effects: A Comment on Rohrer, Pashler, and Harris (2015) and Vohs (2015)

    Science.gov (United States)

    2016-01-01

    When a series of studies fails to replicate a well-documented effect, researchers might be tempted to use a “vote counting” approach to decide whether the effect is reliable—that is, simply comparing the number of successful and unsuccessful replications. Vohs’s (2015) response to the absence of money priming effects reported by Rohrer, Pashler, and Harris (2015) provides an example of this approach. Unfortunately, vote counting is a poor strategy to assess the reliability of psychological findings because it neglects the impact of selection bias and questionable research practices. In the present comment, we show that a range of meta-analytic tools indicate irregularities in the money priming literature discussed by Rohrer et al. and Vohs, which all point to the conclusion that these effects are distorted by selection bias, reporting biases, or p-hacking. This could help to explain why money-priming effects have proven unreliable in a number of direct replication attempts in which biases have been minimized through preregistration or transparent reporting. Our major conclusion is that the simple proportion of significant findings is a poor guide to the reliability of research and that preregistered replications are an essential means to assess the reliability of money-priming effects. PMID:27077759

  18. Selection bias, vote counting, and money-priming effects: A comment on Rohrer, Pashler, and Harris (2015) and Vohs (2015).

    Science.gov (United States)

    Vadillo, Miguel A; Hardwicke, Tom E; Shanks, David R

    2016-05-01

    When a series of studies fails to replicate a well-documented effect, researchers might be tempted to use a "vote counting" approach to decide whether the effect is reliable-that is, simply comparing the number of successful and unsuccessful replications. Vohs's (2015) response to the absence of money priming effects reported by Rohrer, Pashler, and Harris (2015) provides an example of this approach. Unfortunately, vote counting is a poor strategy to assess the reliability of psychological findings because it neglects the impact of selection bias and questionable research practices. In the present comment, we show that a range of meta-analytic tools indicate irregularities in the money priming literature discussed by Rohrer et al. and Vohs, which all point to the conclusion that these effects are distorted by selection bias, reporting biases, or p-hacking. This could help to explain why money-priming effects have proven unreliable in a number of direct replication attempts in which biases have been minimized through preregistration or transparent reporting. Our major conclusion is that the simple proportion of significant findings is a poor guide to the reliability of research and that preregistered replications are an essential means to assess the reliability of money-priming effects.

  19. Effect of an Intervention to Break the Gender Bias Habit for Faculty at One Institution: A Cluster Randomized, Controlled Trial

    Science.gov (United States)

    Carnes, Molly; Devine, Patricia G.; Manwell, Linda Baier; Byars-Winston, Angela; Fine, Eve; Ford, Cecilia E.; Forscher, Patrick; Isaac, Carol; Kaatz, Anna; Magua, Wairimu; Palta, Mari; Sheridan, Jennifer

    2014-01-01

    Purpose Despite sincere commitment to egalitarian, meritocratic principles, subtle gender bias persists, constraining women’s opportunities for academic advancement. The authors implemented a pair-matched, single-blind, cluster-randomized, controlled study of a gender bias habit-changing intervention at a large public university. Method Participants were faculty in 92 departments or divisions at the University of Wisconsin-Madison. Between September 2010 and March 2012, experimental departments were offered a gender bias habit-changing intervention as a 2.5 hour workshop. Surveys measured gender bias awareness; motivation, self-efficacy, and outcome expectations to reduce bias; and gender equity action. A timed word categorization task measured implicit gender/leadership bias. Faculty completed a worklife survey before and after all experimental departments received the intervention. Control departments were offered workshops after data were collected. Results Linear mixed-effects models showed significantly greater changes post-intervention for faculty in experimental vs. control departments on several outcome measures, including self-efficacy to engage in gender equity promoting behaviors (P = .013). When ≥ 25% of a department’s faculty attended the workshop (26 of 46 departments), significant increases in self-reported action to promote gender equity occurred at 3 months (P = .007). Post-intervention, faculty in experimental departments expressed greater perceptions of fit (P = .024), valuing of their research (P = .019), and comfort in raising personal and professional conflicts (P = .025). Conclusions An intervention that facilitates intentional behavioral change can help faculty break the gender bias habit and change department climate in ways that should support the career advancement of women in academic medicine, science, and engineering. PMID:25374039

  20. Osmotic and Heat Stress Effects on Segmentation

    Science.gov (United States)

    Weiss, Julian

    2016-01-01

    During vertebrate embryonic development, early skin, muscle, and bone progenitor populations organize into segments known as somites. Defects in this conserved process of segmentation lead to skeletal and muscular deformities, such as congenital scoliosis, a curvature of the spine caused by vertebral defects. Environmental stresses such as hypoxia or heat shock produce segmentation defects, and significantly increase the penetrance and severity of vertebral defects in genetically susceptible individuals. Here we show that a brief exposure to a high osmolarity solution causes reproducible segmentation defects in developing zebrafish (Danio rerio) embryos. Both osmotic shock and heat shock produce border defects in a dose-dependent manner, with an increase in both frequency and severity of defects. We also show that osmotic treatment has a delayed effect on somite development, similar to that observed in heat shocked embryos. Our results establish osmotic shock as an alternate experimental model for stress, affecting segmentation in a manner comparable to other known environmental stressors. The similar effects of these two distinct environmental stressors support a model in which a variety of cellular stresses act through a related response pathway that leads to disturbances in the segmentation process. PMID:28006008

  1. Tunnel design considering stress release effect

    Institute of Scientific and Technical Information of China (English)

    Van-hung DAO

    2009-01-01

    In tunnel design,the determination of installation time and the stiffness of supporting structures is very important to the tunnel stability.This study used the convergence-confinement method to determine the stress and displacement of the tunnel while considering the counter-pressure curve of the ground base,the stress release effect,and the interaction between the tunnel lining and the rock surrounding the tunnel chamber.The results allowed for the determination of the installation time,distribution and strength of supporting structures.This method was applied to the intake tunnel in the Ban Ve Hydroelectric Power Plant,in Nghe An Province,Vietnam.The results show that when a suitable displacement u0 ranging from 0.0865 m to 0.0919 m occurrs,we can install supporting structures that satisfy the stability and economical requirements.

  2. Static and dynamic effective stress coefficient of chalk

    DEFF Research Database (Denmark)

    Alam, M. Monzurul; Fabricius, Ida Lykke; Christensen, Helle Foged

    2012-01-01

    Deformation of a hydrocarbon reservoir can ideally be used to estimate the effective stress acting on it. The effective stress in the subsurface is the difference between the stress due to the weight of the sediment and a fraction (effective stress coefficient) of the pore pressure. The effective...... elastic deformation caused by pore pressure buildup, for example, during waterflooding. By contrast, during the increase in differential stress, as in the case of pore pressure depletion due to production, n increases with stress while α decreases.......Deformation of a hydrocarbon reservoir can ideally be used to estimate the effective stress acting on it. The effective stress in the subsurface is the difference between the stress due to the weight of the sediment and a fraction (effective stress coefficient) of the pore pressure. The effective...... stress coefficient is thus relevant for studying reservoir deformation and for evaluating 4D seismic for the correct pore pressure prediction. The static effective stress coefficient n is estimated from mechanical tests and is highly relevant for effective stress prediction because it is directly related...

  3. Interpretation biases in paranoia.

    Science.gov (United States)

    Savulich, George; Freeman, Daniel; Shergill, Sukhi; Yiend, Jenny

    2015-01-01

    Information in the environment is frequently ambiguous in meaning. Emotional ambiguity, such as the stare of a stranger, or the scream of a child, encompasses possible good or bad emotional consequences. Those with elevated vulnerability to affective disorders tend to interpret such material more negatively than those without, a phenomenon known as "negative interpretation bias." In this study we examined the relationship between vulnerability to psychosis, measured by trait paranoia, and interpretation bias. One set of material permitted broadly positive/negative (valenced) interpretations, while another allowed more or less paranoid interpretations, allowing us to also investigate the content specificity of interpretation biases associated with paranoia. Regression analyses (n=70) revealed that trait paranoia, trait anxiety, and cognitive inflexibility predicted paranoid interpretation bias, whereas trait anxiety and cognitive inflexibility predicted negative interpretation bias. In a group comparison those with high levels of trait paranoia were negatively biased in their interpretations of ambiguous information relative to those with low trait paranoia, and this effect was most pronounced for material directly related to paranoid concerns. Together these data suggest that a negative interpretation bias occurs in those with elevated vulnerability to paranoia, and that this bias may be strongest for material matching paranoid beliefs. We conclude that content-specific biases may be important in the cause and maintenance of paranoid symptoms.

  4. Field-free magnetization reversal by spin-Hall effect and exchange bias.

    Science.gov (United States)

    van den Brink, A; Vermijs, G; Solignac, A; Koo, J; Kohlhepp, J T; Swagten, H J M; Koopmans, B

    2016-03-04

    As the first magnetic random access memories are finding their way onto the market, an important issue remains to be solved: the current density required to write magnetic bits becomes prohibitively high as bit dimensions are reduced. Recently, spin-orbit torques and the spin-Hall effect in particular have attracted significant interest, as they enable magnetization reversal without high current densities running through the tunnel barrier. For perpendicularly magnetized layers, however, the technological implementation of the spin-Hall effect is hampered by the necessity of an in-plane magnetic field for deterministic switching. Here we interface a thin ferromagnetic layer with an anti-ferromagnetic material. An in-plane exchange bias is created and shown to enable field-free S HE-driven magnetization reversal of a perpendicularly magnetized Pt/Co/IrMn structure. Aside from the potential technological implications, our experiment provides additional insight into the local spin structure at the ferromagnetic/anti-ferromagnetic interface.

  5. Automation bias: a systematic review of frequency, effect mediators, and mitigators.

    Science.gov (United States)

    Goddard, Kate; Roudsari, Abdul; Wyatt, Jeremy C

    2012-01-01

    Automation bias (AB)--the tendency to over-rely on automation--has been studied in various academic fields. Clinical decision support systems (CDSS) aim to benefit the clinical decision-making process. Although most research shows overall improved performance with use, there is often a failure to recognize the new errors that CDSS can introduce. With a focus on healthcare, a systematic review of the literature from a variety of research fields has been carried out, assessing the frequency and severity of AB, the effect mediators, and interventions potentially mitigating this effect. This is discussed alongside automation-induced complacency, or insufficient monitoring of automation output. A mix of subject specific and freetext terms around the themes of automation, human-automation interaction, and task performance and error were used to search article databases. Of 13 821 retrieved papers, 74 met the inclusion criteria. User factors such as cognitive style, decision support systems (DSS), and task specific experience mediated AB, as did attitudinal driving factors such as trust and confidence. Environmental mediators included workload, task complexity, and time constraint, which pressurized cognitive resources. Mitigators of AB included implementation factors such as training and emphasizing user accountability, and DSS design factors such as the position of advice on the screen, updated confidence levels attached to DSS output, and the provision of information versus recommendation. By uncovering the mechanisms by which AB operates, this review aims to help optimize the clinical decision-making process for CDSS developers and healthcare practitioners.

  6. Field-free magnetization reversal by spin-Hall effect and exchange bias

    Science.gov (United States)

    van den Brink, A.; Vermijs, G.; Solignac, A.; Koo, J.; Kohlhepp, J. T.; Swagten, H. J. M.; Koopmans, B.

    2016-03-01

    As the first magnetic random access memories are finding their way onto the market, an important issue remains to be solved: the current density required to write magnetic bits becomes prohibitively high as bit dimensions are reduced. Recently, spin-orbit torques and the spin-Hall effect in particular have attracted significant interest, as they enable magnetization reversal without high current densities running through the tunnel barrier. For perpendicularly magnetized layers, however, the technological implementation of the spin-Hall effect is hampered by the necessity of an in-plane magnetic field for deterministic switching. Here we interface a thin ferromagnetic layer with an anti-ferromagnetic material. An in-plane exchange bias is created and shown to enable field-free S HE-driven magnetization reversal of a perpendicularly magnetized Pt/Co/IrMn structure. Aside from the potential technological implications, our experiment provides additional insight into the local spin structure at the ferromagnetic/anti-ferromagnetic interface.

  7. Stress effects on memory : An update and integration

    NARCIS (Netherlands)

    Schwabe, Lars; Joëls, Marian; Roozendaal, Benno; Wolf, Oliver T.; Oitzl, Melly S.

    2012-01-01

    It is well known that stressful experiences may affect learning and memory processes. Less clear is the exact nature of these stress effects on memory: both enhancing and impairing effects have been reported. These opposite effects may be explained if the different time courses of stress hormone, in

  8. Stress effects on memory: an update and integration

    NARCIS (Netherlands)

    Schwabe, L.; Joels, M.; Roozendaal, B.; Wolf, O.T.; Oitzl, M.S.

    2012-01-01

    It is well known that stressful experiences may affect learning and memory processes. Less clear is the exact nature of these stress effects on memory: both enhancing and impairing effects have been reported. These opposite effects may be explained if the different time courses of stress hormone, in

  9. Batch effect confounding leads to strong bias in performance estimates obtained by cross-validation.

    Directory of Open Access Journals (Sweden)

    Charlotte Soneson

    Full Text Available With the large amount of biological data that is currently publicly available, many investigators combine multiple data sets to increase the sample size and potentially also the power of their analyses. However, technical differences ("batch effects" as well as differences in sample composition between the data sets may significantly affect the ability to draw generalizable conclusions from such studies.The current study focuses on the construction of classifiers, and the use of cross-validation to estimate their performance. In particular, we investigate the impact of batch effects and differences in sample composition between batches on the accuracy of the classification performance estimate obtained via cross-validation. The focus on estimation bias is a main difference compared to previous studies, which have mostly focused on the predictive performance and how it relates to the presence of batch effects.We work on simulated data sets. To have realistic intensity distributions, we use real gene expression data as the basis for our simulation. Random samples from this expression matrix are selected and assigned to group 1 (e.g., 'control' or group 2 (e.g., 'treated'. We introduce batch effects and select some features to be differentially expressed between the two groups. We consider several scenarios for our study, most importantly different levels of confounding between groups and batch effects.We focus on well-known classifiers: logistic regression, Support Vector Machines (SVM, k-nearest neighbors (kNN and Random Forests (RF. Feature selection is performed with the Wilcoxon test or the lasso. Parameter tuning and feature selection, as well as the estimation of the prediction performance of each classifier, is performed within a nested cross-validation scheme. The estimated classification performance is then compared to what is obtained when applying the classifier to independent data.

  10. Substrate bias effects on collector resistance in SiGe heterojunction bipolar transistors on thin film silicon-on-insulator

    Institute of Scientific and Technical Information of China (English)

    Xu Xiao-Bo; Zhang He-Ming; Hu Hui-Yong; Qu Jiang-Tao

    2011-01-01

    An analytical expression for the collector resistance of a novel vertical SiGe heteroj unction bipolar transistor (HBT)on thin film silicon-on-insulator (SOI) is obtained with the substrate bias effects being considered. The resistance is found to decrease slowly and then quickly and to have kinks with the increase of the substrate-collector bias, which is quite different from that of a conventional bulk HBT. The model is consistent with the simulation result and the reported data and is useful to the frequency characteristic design of 0.13 μm millimeter-wave SiGe SOI BiCMOS devices.

  11. Acute stress does not affect the impairing effect of chronic stress on memory retrieval

    Directory of Open Access Journals (Sweden)

    Jamile Ozbaki

    2016-07-01

    Full Text Available Objective(s: Due to the prevalence and pervasiveness of stress in modern life and exposure to both chronic and acute stresses, it is not clear whether prior exposure to chronic stress can influence the impairing effects of acute stress on memory retrieval. This issue was tested in this study. Materials and Methods: Adult male Wistar rats were randomly assigned to the following groups: control, acute, chronic, and chronic + acute stress groups. The rats were trained with six trials per day for 6 consecutive days in the water maze. Following training, the rats were either kept in control conditions or exposed to chronic stress in a restrainer 6 hr/day for 21 days. On day 22, a probe test was done to measure memory retention. Time spent in target and opposite areas, platform location latency, and proximity were used as indices of memory retention. To induce acute stress, 30 min before the probe test, animals received a mild footshock. Results: Stressed animals spent significantly less time in the target quadrant and more time in the opposite quadrant than control animals. Moreover, the stressed animals showed significantly increased platform location latency and proximity as compared with control animals. No significant differences were found in these measures among stress exposure groups. Finally, both chronic and acute stress significantly increased corticosterone levels. Conclusion: Our results indicate that both chronic and acute stress impair memory retrieval similarly. Additionally, the impairing effects of chronic stress on memory retrieval were not influenced by acute stress.

  12. Reversible and irreversible temperature-induced changes in exchange-biased planar Hall effect bridge (PHEB) magnetic field sensors

    DEFF Research Database (Denmark)

    Rizzi, G.; Lundtoft, N.C.; Østerberg, F.W.

    2012-01-01

    We investigate the changes of planar Hall effect bridge magnetic field sensors upon exposure to temperatures between 25° C and 90°C. From analyses of the sensor response vs. magnetic fields we extract the exchange bias field Hex, the uniaxial anisotropy field HK and the anisotropic...... magnetoresistance (AMR) of the exchange biased thin film at a given temperature and by comparing measurements carried out at elevated temperatures T with measurements carried out at 25° C after exposure to T, we can separate the reversible from the irreversible changes of the sensor. The results are not only...... relevant for sensor applications but also demonstrate the method as a useful tool for characterizing exchange-biased thin films....

  13. Hysteresis analysis in dye-sensitized solar cells based on external bias field effects

    Science.gov (United States)

    Wu, Fan; Li, Xiaoyi; Tong, Yanhua; Zhang, Tiansheng

    2017-02-01

    The current density-voltage (J-V) hysteresis phenomenon occurs in perovskite solar cells as well as dye-sensitized solar cells (DSCs); however, it has received little attention in DSCs. We consider that the trapping-detrapping-induced variation of the charge collection efficiency might cause J-V hysteresis. Therefore, we conduct a systematic study on the influence of an external bias field during and before J-V measurements in typical DSCs. We find that the J-V performance of DSCs significantly depends on the scan bias direction and the external bias field before and during measurements. Our results indicate that the external-bias-field-modulated charge injection, trapping-detrapping, and accumulation processes in DSCs are possible causes for the anomalous J-V behavior.

  14. Effect of asymmetric molecule-electrode coupling and molecular bias on rectification in molecular junctions

    Science.gov (United States)

    Kaur, Rupan Preet; Sawhney, Ravinder Singh; Engles, Derick

    2016-12-01

    In this research work, we compare the rectification trends of two symmetrical and one asymmetrical molecular junction formed with gold and silver electrodes bridging benzenedithiol molecule. The origin of rectification is attributed to both molecular bias drop and asymmetric molecule-electrode coupling. The electronic transport properties are computed by using semi-empirical extended Huckel method combined with non-equilibrium Green's function framework. The results are fully rationalized by analysing the distribution of molecular orbitals with changing bias voltage, available density of states and area of transmission spectra spanned within bias window, transmission eigenstates and transmission pathways. We deduce through this work that the molecular rectification is not only the property of asymmetric molecule-metal coupling, but molecular bias also plays vital role in stemming asymmetric I- V characteristics. Our results suggest how to realize molecular rectification by using different electrode materials which act as Schottky barriers in molecular junctions that emulate p-n junction diode in semiconductor electronics.

  15. Effects of Symptoms of ADHD, ODD, and Cognitive Functioning on Social Acceptance and the Positive Illusory Bias in Children

    Science.gov (United States)

    Scholtens, Sara; Diamantopoulou, Sofia; Tillman, Carin M.; Rydell, Ann-Margret

    2012-01-01

    Objective: To examine the effects of symptoms of ADHD and ODD and cognitive functioning on social acceptance and positive bias in children. Method: The sample consisted of 86 children (49 girls) between 7 and 13 years old, recruited to reflect a wide range of ADHD symptoms. Parents and teachers reported on ADHD and ODD symptoms and social…

  16. Measuring treatment and scale bias effects by linear regression in the analysis of OHI-S scores.

    Science.gov (United States)

    Moore, B J

    1977-05-01

    A linear regression model is presented for estimating unbiased treatment effects from OHI-S scores. An example is given to illustrate an analysis and to compare results of an unbiased regression estimator with those based on a biased simple difference estimator.

  17. The role of attentional bias in the effect of food advertising on actual food intake among children

    NARCIS (Netherlands)

    Folkvord, F.; Anschütz, D.J.; Wiers, R.W.; Buijzen, M.

    2015-01-01

    This study examined the potential moderating role of attentional bias (i.e., gaze duration, number of fixations, latency of initial fixation) in the effect of advergames promoting energy-dense snacks on children's snack intake. A randomized between-subject design was conducted with 92 children who p

  18. Collider Bias in Trauma Comparative Effectiveness Research: The Stratification Blues for Systematic Reviews

    Science.gov (United States)

    2015-05-01

    beyond the highest- risk interval and long enough to ensure definitive diagnosis and interventions, the following study conditions would be required...cause (confounder) of both the treatment and outcome of interest. A familiar example of collider bias is Berkson’s bias or fallacy [9]. In his 1946...14. ABSTRACT 15. SUBJECT TERMS 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT SAR 18. NUMBER OF PAGES 6 19a. NAME OF RESPONSIBLE

  19. Cochlear compression: effects of low-frequency biasing on quadratic distortion product otoacoustic emission.

    Science.gov (United States)

    Bian, Lin

    2004-12-01

    Distortion product otoacoustic emissions (DPOAEs) are generated from the nonlinear transduction n cochlear outer hair cells. The transducer function demonstrating a compressive nonlinearity can be estimated from low-frequency modulation of DPOAEs. Experimental results from the gerbils showed that the magnitude of quadratic difference tone (QDT, f2-f1) was either enhanced or suppressed depending on the phase of the low-frequency bias tone. Within one period of the bias tone, QDT magnitudes exhibited two similar modulation patterns, each resembling the absolute value of the second derivative of the transducer function. In the time domain, the center notches of the modulation patterns occurred around the zero crossings of the bias pressure, whereas peaks corresponded to the increase or decrease in bias pressure. Evaluated with respect to the bias pressure, modulated QDT magnitude displayed a double-modulation pattern marked by a separation of the center notches. Loading/unloading of the cochlear transducer or rise/fall in bias pressure shifted the center notch to positive or negative sound pressures, indicating a mechanical hysteresis. These results suggest that QDT arises from the compression that coexists with the active hysteresis in cochlear transduction. Modulation of QDT magnitude reflects the dynamic regulation of cochlear transducer gain and compression.

  20. The effects of stress on glutamatergic transmission in the brain.

    Science.gov (United States)

    Yuan, Ti-Fei; Hou, Gonglin

    2015-01-01

    Stress leads to detrimental effects on brain functions and results in various diseases. Recent studies highlight the involvement of glutamatergic transmission in pathogenesis of depressive behaviors and fears. Acute stress generates different impacts on the excitatory transmission compared to chronic stress. Different neuromodulators and epigenetic factors also participate in the alteration of synaptic transmission and the regulation of synaptic plasticity. Restoration of the glutamatergic transmission in stress-affected brain areas therefore provides novel directions of therapeutic interventions against stress.

  1. The Effects of Obesity-Related Health Messages on Explicit and Implicit Weight Bias

    Science.gov (United States)

    Rudolph, Almut; Hilbert, Anja

    2017-01-01

    The pervasiveness of explicit and implicit weight bias (WB) defined as negative stereotypes and prejudice regarding one’s weight has been observed among individuals of all weight categories. As a source of WB, health messages have been discussed due to reinforcing stigmatizing notions. The present study sought to investigate whether health messages (i.e., eat healthy, become physically active) have the potential to increase explicit and implicit WB. Participants (N = 144) from the community were randomized to either an experimental group (EG) or a control group (CG). While the EG was presented with health messages, the CG was presented with neutral information. Before and after manipulation, participants completed measures of explicit and implicit WB. Paired samples t-test revealed no differences in explicit WB after manipulation, however, a small effect decrease of implicit WB in the EG but not in the CG was found. This study provided evidence that health messages might have differential impact to change WB. According to dual-model approaches, explicit and implicit WB tap into two different information processing systems, and thus were differentially affected by health messages. Brief exposure to health messages might have the potential to contribute to health behavior and to mitigate implicit WB. PMID:28123375

  2. Temperature, Magnetic field, and Gate Bias Dependence of the Infrared Hall Effect in Graphene

    Science.gov (United States)

    Ellis, C. T.; Stier, A. V.; Stabile, A.; Kim, M.-H.; Sambandamurthy, G.; Cerne, J.; Banerjee, S.

    2010-03-01

    In our study we probe the infrared Hall conductivity (σxy) for single and bilayer graphene in the 120-1000 meV range as a function of gate bias at temperatures down to 7K and magnetic fields up to 7T using Faraday measurements. Unlike the longitudinal conductivity (σxx), which measures the sum of the optical responses for left and right circularly polarized light, σxy measures the difference and therefore is sensitive to small changes in symmetry. While σxx and the DC Hall effect have revealed extraordinary properties of graphene (Zhang, Nature 2005; Novoselov, Nature 2005; Jiang, PRL 2007; etc...) recent calculations (Morimoto, PRL 2009) predict remarkable step-like features in the infrared σxy. We also probe the chiral response of graphene due to spatial inversion symmetry breaking. Our graphene samples are prepared using several methods, including anodically bonding graphite to pyrex, which can produce a high yield of large single layer graphene flakes (>100 μm) (Shukla et al., Solid State Comm. 2009), normal mechanical exfoliation of kish graphite, and grown chemical vapor deposition techniques.

  3. The effect of research-based instruction in introductory physics on a common cognitive bias

    Science.gov (United States)

    Galloway, Ross K.; Bates, Simon P.; Parker, Jonathan; Usoskina, Evguenia

    2013-01-01

    Inspired by a paper at last year's PERC conference, in which Rebello [1] compared students' individual and cohort mean score estimations with their actual assessment scores, we present results of a study in which students in an introductory physics class were asked to predict their scores on two assessments, one delivered at the start of the course (pre-instruction) and one at the end of the course (post-instruction). Our results show that, pre-instruction, the academically strongest students tend to underestimate their score slightly, whereas the weakest overestimate their performance significantly, consistent with the findings of Rebello and demonstrating a well-known cognitive bias (the Dunning-Kruger effect). Post-instruction, we find that the ability of the original weakest quartile cohort to accurately predict their own assessment score has improved significantly, but a flux of students between quartiles from one assessment to the other reveals that the least able students continue to over-estimate their performance, but with a reduced mean discrepancy. We discuss the implications these results have for instruction and for development of enhanced metacognition amongst physics students.

  4. Sex-specific effects of a parasite evolving in a female-biased host population

    Directory of Open Access Journals (Sweden)

    Duneau David

    2012-12-01

    Full Text Available Abstract Background Males and females differ in many ways and might present different opportunities and challenges to their parasites. In the same way that parasites adapt to the most common host type, they may adapt to the characteristics of the host sex they encounter most often. To explore this hypothesis, we characterized host sex-specific effects of the parasite Pasteuria ramosa, a bacterium evolving in naturally, strongly, female-biased populations of its host Daphnia magna. Results We show that the parasite proliferates more successfully in female hosts than in male hosts, even though males and females are genetically identical. In addition, when exposure occurred when hosts expressed a sexual dimorphism, females were more infected. In both host sexes, the parasite causes a similar reduction in longevity and leads to some level of castration. However, only in females does parasite-induced castration result in the gigantism that increases the carrying capacity for the proliferating parasite. Conclusions We show that mature male and female Daphnia represent different environments and reveal one parasite-induced symptom (host castration, which leads to increased carrying capacity for parasite proliferation in female but not male hosts. We propose that parasite induced host castration is a property of parasites that evolved as an adaptation to specifically exploit female hosts.

  5. Predicting bee community responses to land-use changes: Effects of geographic and taxonomic biases

    Science.gov (United States)

    De Palma, Adriana; Abrahamczyk, Stefan; Aizen, Marcelo A.; Albrecht, Matthias; Basset, Yves; Bates, Adam; Blake, Robin J.; Boutin, Céline; Bugter, Rob; Connop, Stuart; Cruz-López, Leopoldo; Cunningham, Saul A.; Darvill, Ben; Diekötter, Tim; Dorn, Silvia; Downing, Nicola; Entling, Martin H.; Farwig, Nina; Felicioli, Antonio; Fonte, Steven J.; Fowler, Robert; Franzén, Markus; Goulson, Dave; Grass, Ingo; Hanley, Mick E.; Hendrix, Stephen D.; Herrmann, Farina; Herzog, Felix; Holzschuh, Andrea; Jauker, Birgit; Kessler, Michael; Knight, M. E.; Kruess, Andreas; Lavelle, Patrick; Le Féon, Violette; Lentini, Pia; Malone, Louise A.; Marshall, Jon; Pachón, Eliana Martínez; McFrederick, Quinn S.; Morales, Carolina L.; Mudri-Stojnic, Sonja; Nates-Parra, Guiomar; Nilsson, Sven G.; Öckinger, Erik; Osgathorpe, Lynne; Parra-H, Alejandro; Peres, Carlos A.; Persson, Anna S.; Petanidou, Theodora; Poveda, Katja; Power, Eileen F.; Quaranta, Marino; Quintero, Carolina; Rader, Romina; Richards, Miriam H.; Roulston, T’ai; Rousseau, Laurent; Sadler, Jonathan P.; Samnegård, Ulrika; Schellhorn, Nancy A.; Schüepp, Christof; Schweiger, Oliver; Smith-Pardo, Allan H.; Steffan-Dewenter, Ingolf; Stout, Jane C.; Tonietto, Rebecca K.; Tscharntke, Teja; Tylianakis, Jason M.; Verboven, Hans A. F.; Vergara, Carlos H.; Verhulst, Jort; Westphal, Catrin; Yoon, Hyung Joo; Purvis, Andy

    2016-01-01

    Land-use change and intensification threaten bee populations worldwide, imperilling pollination services. Global models are needed to better characterise, project, and mitigate bees' responses to these human impacts. The available data are, however, geographically and taxonomically unrepresentative; most data are from North America and Western Europe, overrepresenting bumblebees and raising concerns that model results may not be generalizable to other regions and taxa. To assess whether the geographic and taxonomic biases of data could undermine effectiveness of models for conservation policy, we have collated from the published literature a global dataset of bee diversity at sites facing land-use change and intensification, and assess whether bee responses to these pressures vary across 11 regions (Western, Northern, Eastern and Southern Europe; North, Central and South America; Australia and New Zealand; South East Asia; Middle and Southern Africa) and between bumblebees and other bees. Our analyses highlight strong regionally-based responses of total abundance, species richness and Simpson's diversity to land use, caused by variation in the sensitivity of species and potentially in the nature of threats. These results suggest that global extrapolation of models based on geographically and taxonomically restricted data may underestimate the true uncertainty, increasing the risk of ecological surprises. PMID:27509831

  6. Height bias and scale effect induced by antenna gravitational deformations in geodetic VLBI data analysis

    Science.gov (United States)

    Sarti, Pierguido; Abbondanza, Claudio; Petrov, Leonid; Negusini, Monia

    2011-01-01

    The impact of signal path variations (SPVs) caused by antenna gravitational deformations on geodetic very long baseline interferometry (VLBI) results is evaluated for the first time. Elevation-dependent models of SPV for Medicina and Noto (Italy) telescopes were derived from a combination of terrestrial surveying methods to account for gravitational deformations. After applying these models in geodetic VLBI data analysis, estimates of the antenna reference point positions are shifted upward by 8.9 and 6.7 mm, respectively. The impact on other parameters is negligible. To simulate the impact of antenna gravitational deformations on the entire VLBI network, lacking measurements for other telescopes, we rescaled the SPV models of Medicina and Noto for other antennas according to their size. The effects of the simulations are changes in VLBI heights in the range [-3, 73] mm and a net scale increase of 0.3-0.8 ppb. The height bias is larger than random errors of VLBI position estimates, implying the possibility of significant scale distortions related to antenna gravitational deformations. This demonstrates the need to precisely measure gravitational deformations of other VLBI telescopes, to derive their precise SPV models and to apply them in routine geodetic data analysis.

  7. Simulation of Electron Energy Spectra of a Biased Paracentric Hemispherical Deflection Analyzer as a Function of Entry Bias: Effects of Misalignments

    Directory of Open Access Journals (Sweden)

    O. Sise

    2014-01-01

    Full Text Available The performance of a biased paracentric hemispherical deflection analyzer (HDA, including fringing fields and their effect on focusing and energy resolution, is investigated using numerical methods. Electron energy spectra are calculated for three entry positions R0=84 mm, 100 mm, and 112 mm and compared with the recent experimental measurements. In both experiment and calculation, the two different paracentric entry positions R0=84 mm and R0=112 mm, on either side of the mean radius of 100 mm, are found to have a base energy resolution of about two times better than the conventional centric entry position R0=100 mm. In order to explain the discrepancies (6–30% between the simulated and the experimental resolutions the focusing characteristics are further investigated for different displacements of the input lens (ΔR0 with respect to the entry position R0 and the tilted input beam axis by αshift in the dispersive direction. We have found that the blame does not in fact lie with the theory and we have shown that the input lens may have been misaligned in the experiment. Slight misalignments affect both the true energy resolution measurement and the transmission of the beam.

  8. Effects of social approval bias on self-reported fruit and vegetable consumption: a randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Marcus Al C

    2008-06-01

    Full Text Available Abstract Background Self-reports of dietary intake in the context of nutrition intervention research can be biased by the tendency of respondents to answer consistent with expected norms (social approval bias. The objective of this study was to assess the potential influence of social approval bias on self-reports of fruit and vegetable intake obtained using both food frequency questionnaire (FFQ and 24-hour recall methods. Methods A randomized blinded trial compared reported fruit and vegetable intake among subjects exposed to a potentially biasing prompt to that from control subjects. Subjects included 163 women residing in Colorado between 35 and 65 years of age who were randomly selected and recruited by telephone to complete what they were told would be a future telephone survey about health. Randomly half of the subjects then received a letter prior to the interview describing this as a study of fruit and vegetable intake. The letter included a brief statement of the benefits of fruits and vegetables, a 5-A-Day sticker, and a 5-a-Day refrigerator magnet. The remainder received the same letter, but describing the study purpose only as a more general nutrition survey, with neither the fruit and vegetable message nor the 5-A-Day materials. Subjects were then interviewed on the telephone within 10 days following the letters using an eight-item FFQ and a limited 24-hour recall to estimate fruit and vegetable intake. All interviewers were blinded to the treatment condition. Results By the FFQ method, subjects who viewed the potentially biasing prompts reported consuming more fruits and vegetables than did control subjects (5.2 vs. 3.7 servings per day, p Conclusion Self-reports of fruit and vegetable intake using either a food frequency questionnaire or a limited 24-hour recall are both susceptible to substantial social approval bias. Valid assessments of intervention effects in nutritional intervention trials may require objective measures of

  9. Investigating Uncertainty in Predicting Carbon Dynamics in North American Biomes: Putting Support-Effect Bias in Perspective

    Science.gov (United States)

    Dungan, Jennifer L.; Brass, Jim (Technical Monitor)

    2001-01-01

    A fundamental strategy in NASA's Earth Observing System's (EOS) monitoring of vegetation and its contribution to the global carbon cycle is to rely on deterministic, process-based ecosystem models to make predictions of carbon flux over large regions. These models are parameterized (that is, the input variables are derived) using remotely sensed images such as those from the Moderate Resolution Imaging Spectroradiometer (MODIS), ground measurements and interpolated maps. Since early applications of these models, investigators have noted that results depend partly on the spatial support of the input variables. In general, the larger the support of the input data, the greater the chance that the effects of important components of the ecosystem will be averaged out. A review of previous work shows that using large supports can cause either positive or negative bias in carbon flux predictions. To put the magnitude and direction of these biases in perspective, we must quantify the range of uncertainty on our best measurements of carbon-related variables made on equivalent areas. In other words, support-effect bias should be placed in the context of prediction uncertainty from other sources. If the range of uncertainty at the smallest support is less than the support-effect bias, more research emphasis should probably be placed on support sizes that are intermediate between those of field measurements and MODIS. If the uncertainty range at the smallest support is larger than the support-effect bias, the accuracy of MODIS-based predictions will be difficult to quantify and more emphasis should be placed on field-scale characterization and sampling. This talk will describe methods to address these issues using a field measurement campaign in North America and "upscaling" using geostatistical estimation and simulation.

  10. Kink effect in AlGaN/GaN high electron mobility transistors by electrical stress

    Institute of Scientific and Technical Information of China (English)

    Ma Xiao-Hua; Ma Ji-Gang; Yang Li-Yuan; He Qiang; Jiao Ying; Ma Ping; Hao Yue

    2011-01-01

    The kink effect is studied in an AlGaN/GaN high electron mobility transistor by measuring DC performance during fresh, short-term stress and recovery cycle with negligible degradation. Vdg plays an assistant role in detrapping electrons and short-term stress results in no creation of new category traps but an increase in number of active traps.A possible mechanism is proposed that electrical stress supplies traps with the electric field for activation and when device is under test field-assisted hot-electrons result in electrons detrapping from traps, thus deteriorating the kink effect. In addition, experiments show that the impact ionization is at a relatively low level, which is not the dominant mechanism compared with trapping effect. We analyse the complicated link between the kink effect and stress bias through groups of electrical stress states: Vds = 0-state, off-state, on-state (on-state with low voltage, high-power state,high field state). Finlly, a conclusion is drawn that electric field brings about more severe kink effect than hot electrons.With the assistance of electric field, hot electrons tend to be possible to modulate the charges in deep-level trap.

  11. Effect of bias condition on heavy ion radiation in bipolar junction transistors

    Institute of Scientific and Technical Information of China (English)

    Liu Chao-Ming; Li Xing-Ji; Geng Hong-Bin; Yang De-Zhuang; He Shi-Yu

    2012-01-01

    The characteristic degradations in a silicon NPN bipolar junction transistor (BJT) of 3DG142 type are examined under irradiation with 40-MeV chlorine (Cl) ions under forward,grounded,and reverse bias conditions,respectively.Different electrical parameters are in-situ measured during the exposure under each bias condition.From the experimental data,a larger variation of base current (IB) is observed after irradiation at a given value of base-emitter voltage (VBE),while the collector current is slightly affected by irradiation at a given VBE.The gain degradation is affected mostly by the behaviour of the base current.From the experimental data,the variation of current gain in the case of forward bias is much smaller than that in the other conditions.Moreover,for 3DG142 BJT,the current gain degradation in the case of reverse bias is more severe than that in the grounded case at low fluence,while at high fluence,the gain degradation in the reverse bias case becomes smaller than that in the grounded case.

  12. Effect of bias condition on heavy ion radiation in bipolar junction transistors

    Science.gov (United States)

    Liu, Chao-Ming; Li, Xing-Ji; Geng, Hong-Bin; Yang, De-Zhuang; He, Shi-Yu

    2012-08-01

    The characteristic degradations in a silicon NPN bipolar junction transistor (BJT) of 3DG142 type are examined under irradiation with 40-MeV chlorine (Cl) ions under forward, grounded, and reverse bias conditions, respectively. Different electrical parameters are in-situ measured during the exposure under each bias condition. From the experimental data, a larger variation of base current (IB) is observed after irradiation at a given value of base-emitter voltage (VBE), while the collector current is slightly affected by irradiation at a given VBE. The gain degradation is affected mostly by the behaviour of the base current. From the experimental data, the variation of current gain in the case of forward bias is much smaller than that in the other conditions. Moreover, for 3DG142 BJT, the current gain degradation in the case of reverse bias is more severe than that in the grounded case at low fluence, while at high fluence, the gain degradation in the reverse bias case becomes smaller than that in the grounded case.

  13. Effect of ball milling and thermal treatment on exchange bias and magnetocaloric properties of Ni48Mn39.5Sn10.5Al2 ribbons

    Science.gov (United States)

    Czaja, P.; Przewoźnik, J.; Fitta, M.; Bałanda, M.; Chrobak, A.; Kania, B.; Zackiewicz, P.; Wójcik, A.; Szlezynger, M.; Maziarz, W.

    2016-03-01

    The combined effect of ball milling and subsequent heat treatment on microstructure, magnetic, magnetocaloric and exchange bias properties of Ni48Mn39.5Sn10.5Al2 ribbons is reported. The annealing treatment results in the increase of the critical martensitic transformation temperature. The magnetic entropy change ΔSM of the order of 7.9 and -2.3 J kg K-1 for the annealed 50-32 μm powder fraction is determined. This is less than in the as melt spun ribbon but appears at a considerably higher temperature. At the same time EB is decreased due to annealing treatment. This decrease is attributed to the strengthened ferromagnetic exchange coupling due heat induced stress and structural relaxation.

  14. Brillouin/Raman compensation of the Kerr-effect-induced bias in a nonlinear ring laser gyroscope.

    Science.gov (United States)

    Luo, Zhang; Yuan, Xiaodong; Zhu, Zhihong; Liu, Ken; Ye, Weimin; Zeng, Chun; Ji, Jiarong

    2013-04-01

    In this Letter, the beat frequency at rest of a ring laser gyroscope with nonlinear effects is discussed in detail. Even without an additional intensity-stabilizing system, the random nullshift bias induced by the Kerr effect is compensated by the phase shift associated with the stimulated Brillouin/Raman scattering. And the nonlinear stimulated scattering also serves as the gain mechanism of the gyroscope. And thus the influence of the fluctuation of the injected pump intensity on the beat frequency is eliminated.

  15. Effects of work stress and home stress on autonomic nervous function in Japanese male workers.

    Science.gov (United States)

    Maeda, Eri; Iwata, Toyoto; Murata, Katsuyuki

    2015-01-01

    Autonomic imbalance is one of the important pathways through which psychological stress contributes to cardiovascular diseases/sudden death. Although previous studies have focused mainly on stress at work (work stress), the association between autonomic function and stress at home (home stress) is still poorly understood. The purpose was to clarify the effect of work/home stress on autonomic function in 1,809 Japanese male workers. We measured corrected QT (QTc) interval and QT index on the electrocardiogram along with blood pressure and heart rate. Participants provided self-reported information about the presence/absence of work/home stress and the possible confounders affecting QT indicators. Home stress was related positively to QT index (p=0.040) after adjusting for the possible confounders, though work stress did not show a significant relation to QTc interval or QT index. The odds ratio of home stress to elevated QT index (≥105) was 2.677 (95% CI, 1.050 to 6.822). Work/home stress showed no significant relation to blood pressure or heart rate. These findings suggest that autonomic imbalance, readily assessed by QT indicators, can be induced by home stress in Japanese workers. Additional research is needed to identify different types of home stress that are strongly associated with autonomic imbalance.

  16. Perceived stress and self-esteem mediate the effects of work-related stress on depression.

    Science.gov (United States)

    Lee, Jong-Sun; Joo, Eun-Jeong; Choi, Kyeong-Sook

    2013-02-01

    The aim of the present study was to investigate the impact of perceived stress and self-esteem on work-related stress and depression. Two hundred and eighty-four Korean nurses participated in the study. The participants completed four questionnaires, including the Korean short version of the occupational stress scale, the perceived stress scale, the Rosenberg self-esteem scale and the Beck depression inventory. Structural equation modelling was used to determine the relationships among work-related stress, perceived stress, self-esteem, and depression. Work-related stress was positively associated with depression. Perceived stress was inversely related to self-esteem and positively associated with work-related stress and depression, respectively. Self-esteem was negatively associated with work-related stress and depression. Structural equation modelling revealed that self-esteem and perceived stress fully mediate the relationship between work-related stress and depression. Future studies should further investigate the effect of psychological characteristics on work-related stress and symptoms of depression.

  17. Effects of preventive online mindfulness interventions on stress and mindfulness: A meta-analysis of randomized controlled trials

    Directory of Open Access Journals (Sweden)

    Wasantha P. Jayawardene, MD, PhD

    2017-03-01

    Full Text Available Empirical evidence suggested that mind-body interventions can be effectively delivered online. This study aimed to examine whether preventive online mindfulness interventions (POMI for non-clinical populations improve short- and long-term outcomes for perceived-stress (primary and mindfulness (secondary. Systematic search of four electronic databases, manuscript reference lists, and journal content lists was conducted in 2016, using 21 search-terms. Eight randomized controlled trials (RCTs evaluating effects of POMI in non-clinical populations with adequately reported perceived-stress and mindfulness measures pre- and post-intervention were included. Random-effects models utilized for all effect-size estimations with meta-regression performed for mean age and %females. Participants were volunteers (adults; predominantly female from academic, workplace, or community settings. Most interventions utilized simplified Mindfulness-Based Stress Reduction protocols over 2–12 week periods. Post-intervention, significant medium effect found for perceived-stress (g = 0.432, with moderate heterogeneity and significant, but small, effect size for mindfulness (g = 0.275 with low heterogeneity; highest effects were for middle-aged individuals. At follow-up, significant large effect found for perceived-stress (g = 0.699 with low heterogeneity and significant medium effect (g = 0.466 for mindfulness with high heterogeneity. No publication bias was found for perceived-stress; publication bias found for mindfulness outcomes led to underestimation of effects, not overestimation. Number of eligible RCTs was low with inadequate data reporting in some studies. POMI had substantial stress reduction effects and some mindfulness improvement effects. POMI can be a more convenient and cost-effective strategy, compared to traditional face-to-face interventions, especially in the context of busy, hard-to-reach, but digitally-accessible populations.

  18. Effects of DC bias on magnetic performance of high grades grain-oriented silicon steels

    Science.gov (United States)

    Ma, Guang; Cheng, Ling; Lu, Licheng; Yang, Fuyao; Chen, Xin; Zhu, Chengzhi

    2017-03-01

    When high voltage direct current (HVDC) transmission adopting mono-polar ground return operation mode or unbalanced bipolar operation mode, the invasion of DC current into neutral point of alternating current (AC) transformer will cause core saturation, temperature increasing, and vibration acceleration. Based on the MPG-200D soft magnetic measurement system, the influence of DC bias on magnetic performance of 0.23 mm and 0.27 mm series (P1.7=0.70-1.05 W/kg, B8>1.89 T) grain-oriented (GO) silicon steels under condition of AC / DC hybrid excitation were systematically realized in this paper. For the high magnetic induction GO steels (core losses are the same), greater thickness can lead to stronger ability of resisting DC bias, and the reasons for it were analyzed. Finally, the magnetostriction and A-weighted magnetostriction velocity level of GO steel under DC biased magnetization were researched.

  19. Quantitative description of the azimuthal dependence of the exchange bias effect

    Energy Technology Data Exchange (ETDEWEB)

    Radu, Florin; Westphalen, Andreas; Theis-Broehl, Katharina; Zabel, Hartmut [Institut fuer Experimentalphysik/Festkoerperphysik, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany)

    2006-01-25

    While the principal features of the exchange bias between a ferromagnet and an antiferromagnet are believed to be understood, a quantitative description is still lacking. We show that interface spin disorder is the main reason for the discrepancy of model calculations versus experimental results. Taking into account spin disorder at the interface between the ferromagnet and the antiferromagnet by modifying the well known Meiklejohn and Bean model, an almost perfect agreement can be reached. As an example this is demonstrated for the CoFe/IrMn exchange biased bilayer by analysing the azimuthal dependence of magnetic hysteresis loops from MOKE measurements. Both exchange bias and coercive fields for the complete 360{sup 0} angular range are reproduced by our model. (letter to the editor)

  20. An Exploration Based Cognitive Bias Test for Mice: Effects of Handling Method and Stereotypic Behaviour.

    Directory of Open Access Journals (Sweden)

    Janja Novak

    Full Text Available Behavioural tests to assess affective states are widely used in human research and have recently been extended to animals. These tests assume that affective state influences cognitive processing, and that animals in a negative affective state interpret ambiguous information as expecting a negative outcome (displaying a negative cognitive bias. Most of these tests however, require long discrimination training. The aim of the study was to validate an exploration based cognitive bias test, using two different handling methods, as previous studies have shown that standard tail handling of mice increases physiological and behavioural measures of anxiety compared to cupped handling. Therefore, we hypothesised that tail handled mice would display a negative cognitive bias. We handled 28 female CD-1 mice for 16 weeks using either tail handling or cupped handling. The mice were then trained in an eight arm radial maze, where two adjacent arms predicted a positive outcome (darkness and food, while the two opposite arms predicted a negative outcome (no food, white noise and light. After six days of training, the mice were also given access to the four previously unavailable intermediate ambiguous arms of the radial maze and tested for cognitive bias. We were unable to validate this test, as mice from both handling groups displayed a similar pattern of exploration. Furthermore, we examined whether maze exploration is affected by the expression of stereotypic behaviour in the home cage. Mice with higher levels of stereotypic behaviour spent more time in positive arms and avoided ambiguous arms, displaying a negative cognitive bias. While this test needs further validation, our results indicate that it may allow the assessment of affective state in mice with minimal training-a major confound in current cognitive bias paradigms.

  1. Imagining a brighter future: The effect of positive imagery training on mood, prospective mental imagery and emotional bias in older adults

    OpenAIRE

    Murphy, Susannah E.; Clare O’Donoghue, M.; Drazich, Erin H.S.; BLACKWELL, SIMON E; Christina Nobre, Anna; Emily A Holmes

    2015-01-01

    Positive affect and optimism play an important role in healthy ageing and are associated with improved physical and cognitive health outcomes. This study investigated whether it is possible to boost positive affect and associated positive biases in this age group using cognitive training. The effect of computerised imagery-based cognitive bias modification on positive affect, vividness of positive prospective imagery and interpretation biases in older adults was measured. 77 older adults rece...

  2. SEMICONDUCTOR DEVICES Effect of collector bias current on the linearity of common-emitter BJT amplifiers

    Science.gov (United States)

    Kun, Li; Jianfu, Teng; Xiuwei, Xuan

    2010-12-01

    Using a Volterra series, an explicit formula is derived for the connection between input 3rd-order intercept point and collector bias current (ICQ) in a common-emitter bipolar junction transistor amplifier. The analysis indicates that the larger ICQ is, the more linear the amplifier is. Furthermore, this has been verified by experiment. This study also integrates a method called dynamic bias current for expanding the dynamic range of an LNA (low noise amplifier) as an application of the analysis result obtained above. IMR3 (3rd-order intermodulation rate) is applied to evaluate the LNA's performance with and without adopting this method in this study.

  3. EEG investigations of duration discrimination: the intermodal effect is induced by an attentional bias.

    Directory of Open Access Journals (Sweden)

    Emilie Gontier

    Full Text Available Previous studies indicated that empty time intervals are better discriminated in the auditory than in the visual modality, and when delimited by signals delivered from the same (intramodal intervals rather than from different sensory modalities (intermodal intervals. The present electrophysiological study was conducted to determine the mechanisms which modulated the performances in inter- and intramodal conditions. Participants were asked to categorise as short or long empty intervals marked by auditory (A and/or visual (V signals (intramodal intervals: AA, VV; intermodal intervals: AV, VA. Behavioural data revealed that the performances were higher for the AA intervals than for the three other intervals and lower for inter- compared to intramodal intervals. Electrophysiological results indicated that the CNV amplitude recorded at fronto-central electrodes increased significantly until the end of the presentation of the long intervals in the AA conditions, while no significant change in the time course of this component was observed for the other three modalities of presentation. They also indicated that the N1 and P2 amplitudes recorded after the presentation of the signals which delimited the beginning of the intervals were higher for the inter- (AV/VA compared to the intramodal intervals (AA/VV. The time course of the CNV revealed that the high performances observed with AA intervals would be related to the effectiveness of the neural mechanisms underlying the processing of the ongoing interval. The greater amplitude of the N1 and P2 components during the intermodal intervals suggests that the weak performances observed in these conditions would be caused by an attentional bias induced by the cognitive load and the necessity to switch between modalities.

  4. Expectancy of Stress-Reducing Aromatherapy Effect and Performance on a Stress-Sensitive Cognitive Task

    Directory of Open Access Journals (Sweden)

    Irina Chamine

    2015-01-01

    Full Text Available Objective. Stress-reducing therapies help maintain cognitive performance during stress. Aromatherapy is popular for stress reduction, but its effectiveness and mechanism are unclear. This study examined stress-reducing effects of aromatherapy on cognitive function using the go/no-go (GNG task performance and event related potentials (ERP components sensitive to stress. The study also assessed the importance of expectancy in aromatherapy actions. Methods. 81 adults were randomized to 3 aroma groups (active experimental, detectable, and undetectable placebo and 2 prime subgroups (prime suggesting stress-reducing aroma effects or no-prime. GNG performance, ERPs, subjective expected aroma effects, and stress ratings were assessed at baseline and poststress. Results. No specific aroma effects on stress or cognition were observed. However, regardless of experienced aroma, people receiving a prime displayed faster poststress median reaction times than those receiving no prime. A significant interaction for N200 amplitude indicated divergent ERP patterns between baseline and poststress for go and no-go stimuli depending on the prime subgroup. Furthermore, trends for beneficial prime effects were shown on poststress no-go N200/P300 latencies and N200 amplitude. Conclusion. While there were no aroma-specific effects on stress or cognition, these results highlight the role of expectancy for poststress response inhibition and attention.

  5. The functional activity and effective connectivity of pulvinar are modulated by individual differences in threat-related attentional bias

    Science.gov (United States)

    Hakamata, Yuko; Sato, Eisuke; Komi, Shotaro; Moriguchi, Yoshiya; Izawa, Shuhei; Murayama, Norio; Hanakawa, Takashi; Inoue, Yusuke; Tagaya, Hirokuni

    2016-01-01

    The pulvinar is important in selective attention, particularly to visual stimuli under the focus of attention. However, the pulvinar is assumed to process emotional stimuli even outside the focus of attention, because of its tight connection with the amygdala. We therefore investigated how unattended emotional stimuli affect the pulvinar and its effective connectivity (EC) while considering individual differences in selective attention. fMRI in 41 healthy human subjects revealed that the amygdala, but not the pulvinar, more strongly responded to unattended fearful faces than to unattended neutral faces (UF > UN), although we observed greater EC from the pulvinar to the amygdala. Interestingly, individuals with biased attention toward threat (i.e., attentional bias) showed significantly increased activity (UF > UN) and reduced grey matter volume in the pulvinar. These individuals also exhibited stronger EC from the pulvinar to the attention-related frontoparietal network (FPN), whereas individuals with greater attentional control showed more enhanced EC from the pulvinar to the amygdala, but not the FPN (UF > UN). The pulvinar may filter unattended emotional stimuli whose sensitivity depends on individual threat-related attentional bias. The connectivity patterns of the pulvinar may thus be determined based on individual differences in threat-related attentional bias and attentional control. PMID:27703252

  6. Investigation of Device Performance and Negative Bias Temperature Instability of Plasma Nitrided Oxide in Nanoscale p-Channel Metal-Oxide-Semiconductor Field-Effect Transistor's

    Science.gov (United States)

    Han, In-Shik; Ji, Hee-Hwan; Goo, Tae-Gyu; Yoo, Ook-Sang; Choi, Won-Ho; Na, Min-Ki; Kim, Yong-Goo; Park, Sung-Hyung; Lee, Heui-Seung; Kang, Young-Seok; Kim, Dae-Byung; Lee, Hi-Deok

    2008-04-01

    In this paper, we investigated the device performance and negative bias temperature instability (NBTI) degradation for thermally nitrided oxide (TNO) and plasma nitrided oxide (PNO) in nanoscale p-channel metal oxide semiconductor field effect transistor (PMOSFET). PNOs show the improvement of dielectric performance compared to TNO with no change of the device performance. PNOs also show the improvement of NBTI immunity than TNO at low temperature stress, whereas NBTI immunity of PNO with high N concentration can be worse than TNO at high temperature stress. Recovery effect of NBTI degradation of PNO is lower than that of TNO and it is increased as the N concentration is increased in PNO because the dissociated Si dangling bonds and generated positive oxide charges are repassivated and neutralized, respectively. Moreover, complete recovery of ΔVth is dominated by neutralization of positive oxide charges. Therefore, N contents at polycrystalline Si/SiO2 interface as well as N contents at Si/SiO2 interface can affect significantly on NBTI degradation and recovery effect.

  7. From reorienting of attention to biased competition : Evidence from hemifield effects

    NARCIS (Netherlands)

    Mathot, Sebastiaan; Hickey, Clayton; Theeuwes, Jan

    2010-01-01

    When a distractor was presented simultaneously with or directly following a target, it produced more interference when it was presented in the same visual hemifield as the target than when it was presented in the opposite visual field. This result is interpreted in terms of biased competition; there

  8. A Phenomenological Case Study: Teacher Bias Effects on Early Education Assessments

    Science.gov (United States)

    Reynolds, Rebecca Jeannine

    2012-01-01

    This qualitative phenomenological case study explored the lived experiences of a purposive sample of 20 current and past early education teachers who have experience in assessing children through observational assessment. The purpose of this study was to determine if bias affects the documentation of observational assessment and the implementation…

  9. The Effect of Colour and Size on Attentional Bias to Alcohol-Related Pictures

    Science.gov (United States)

    Harrison, Neil R.; McCann, Amy

    2014-01-01

    Attentional bias plays an important role in the development and maintenance of alcohol addiction, and has often been measured with a visual probe task, where reaction times are compared for probes replacing either a substance-related cue or a neutral cue. Systematic low-level differences between image classes are a potential cause of low internal…

  10. Effects of encoding tasks on the own-age face recognition bias.

    Science.gov (United States)

    Randall, Jason L; Tabernik, Holly E; Aguilera, Aisha M; Anastasi, Jeffrey S; Valk, Kendra V

    2012-01-01

    In the current study, we evaluated the own-age face recognition bias by using various encoding tasks to evaluate the robustness and potential limitations of the own-age bias. One hundred sixty young adults studied photographs of children, young adults, middle-aged adults, and older adults and were assigned to one of four encoding conditions (i.e., age estimate, attractiveness rating, friendliness rating, and a face search task). Subsequent recognition tests revealed a robust own-age bias such that participants recognized own-age faces better than other-age faces regardless of encoding task. The current study showed that encoding tasks that focus on socially relevant characteristics (i.e., attractiveness ratings and friendliness ratings) do not eliminate or weaken the own-age bias compared to tasks that specifically focus on the age of the face. These findings indicate that in-group/out-group categorization requires little conscious processing and may be automatic, which is consistent with Sporer's (2001) in-group/out-group model (IOM) of facial processing.

  11. Preference-Inconsistent Recommendations: An Effective Approach for Reducing Confirmation Bias and Stimulating Divergent Thinking?

    Science.gov (United States)

    Schwind, Christina; Buder, Jurgen; Cress, Ulrike; Hesse, Friedrich W.

    2012-01-01

    The Web is a perfect backdrop for opinion formation as a multitude of different opinions is publicly available. However, the different opinions often remain unexploited: Learners prefer preference-consistent over preference-inconsistent information, a phenomenon called confirmation bias. Two experiments were designed to test whether technologies…

  12. Is Terzaghi’s effective stress a stress variable under seepage conditions?

    Institute of Scientific and Technical Information of China (English)

    雷国辉; 赵仲辉; 吴宏伟

    2015-01-01

    From the continuum mechanics perspective, an attempt was made to clarify the role of Terzaghi’s effective stress in the theoretical analysis of saturated soil subjected to seepage. The necessity of performing a coupled hydromechanical analysis to solve the seepage−deformation interaction problem was illustrated by examining the equations of static equilibrium among the effective stress, seepage force, pore-water pressure and total stress. The conceptual definition of stress variable that satisfies the principles of continuum mechanics is applied in the coupled hydromechanical analysis. It is shown that Terzaghi’s effective stress is in fact not a stress variable under seepage conditions, and the seepage force acting on the soil skeleton cannot be viewed as a body force. This offers a clue to the underlying cause of a paradox between the real Pascal’s hydrostatic state and the hydrostatic state predicted by a class of continuum hydromechanical theories.

  13. Effects of Humor on Teacher Stress, Affect, and Job Satisfaction

    Science.gov (United States)

    Shirley, Jacqueline Dena

    2013-01-01

    Teachers are at high risk for stress, negative emotion, and job dissatisfaction, which has been linked with health problems and early attrition. Humor has been found to relieve various forms of stress. However, there is a gap in the literature regarding humor effects on teacher stress and its related consequences. The purpose of this quantitative,…

  14. The effect of sex-biased dispersal on opposite-sexed spatial genetic structure and inbreeding risk.

    Science.gov (United States)

    Blyton, Michaela D J; Banks, Sam C; Peakall, Rod

    2015-04-01

    Natal sex-biased dispersal has long been thought to reduce the risk of inbreeding by spatially separating opposite-sexed kin. Yet, comprehensive and quantitative evaluations of this hypothesis are lacking. In this study, we quantified the effectiveness of sex-biased dispersal as an inbreeding avoidance strategy by combining spatially explicit simulations and empirical data. We quantified the extent of kin clustering by measuring the degree of spatial autocorrelation among opposite-sexed individuals (FM structure). This allowed us to systematically explore how the extent of sex-biased dispersal, generational overlap, and mate searching distance, influenced both kin clustering, and the resulting inbreeding in the absence of complementary inbreeding avoidance strategies. Simulations revealed that when sex-biased dispersal was limited, positive FM genetic structure developed quickly and increased as the mate searching distance decreased or as generational overlap increased. Interestingly, complete long-range sex-biased dispersal did not prevent the development of FM genetic structure when generations overlapped. We found a very strong correlation between FM genetic structure and both FIS under random mating, and pedigree-based measures of inbreeding. Thus, we show that the detection of FM genetic structure can be a strong indicator of inbreeding risk. Empirical data for two species with different life history strategies yielded patterns congruent with our simulations. Our study illustrates a new application of spatial genetic autocorrelation analysis that offers a framework for quantifying the risk of inbreeding that is easily extendable to other species. Furthermore, our findings provide other researchers with a context for interpreting observed patterns of opposite-sexed spatial genetic structure.

  15. A Comparison of Cognitive Bias Modification for Interpretation and Computerized Cognitive Behavior Therapy: Effects on Anxiety, Depression, Attentional Control, and Interpretive Bias

    Science.gov (United States)

    Bowler, Jennifer O.; Mackintosh, Bundy; Dunn, Barnaby D.; Mathews, Andrew; Dalgleish, Tim; Hoppitt, Laura

    2012-01-01

    Objective: Computerized cognitive behavioral therapy (cCBT) and cognitive bias modification for interpretation (CBM-I) both have demonstrated efficacy in alleviating social anxiety, but how they compare with each other has not been investigated. The present study tested the prediction that both interventions would reduce anxiety relative to a…

  16. Effect of Sample Configuration on Droplet-Particles of TiN Films Deposited by Pulse Biased Arc Ion Plating

    Institute of Scientific and Technical Information of China (English)

    Yanhui Zhao; Guoqiang Lin; Jinquan Xiao; Chuang Dong; Lishi Wen

    2009-01-01

    Orthogonal experiments are used to design the pulsed bias related parameters, including bias magnitude, duty cycle and pulse frequency, during arc ion deposition of TiN films on stainless steel substrates in the case of samples placing normal to the plasma flux. The effect of these parameters on the amount and the size distribution of droplet-particles are investigated, and the results have provided sufficient evidence for the physical model, in which particles reduction is due to the case that the particles are negatively charged and repulsed from negative pulse electric field. The effect of sample configuration on amount and size distribution of the particles are analyzed. The results of the amount and size distribution of the particles are compared to those in the case of samples placing parallel to the plasma flux.

  17. Introduction to Unconscious Bias

    Science.gov (United States)

    Schmelz, Joan T.

    2010-05-01

    We all have biases, and we are (for the most part) unaware of them. In general, men and women BOTH unconsciously devalue the contributions of women. This can have a detrimental effect on grant proposals, job applications, and performance reviews. Sociology is way ahead of astronomy in these studies. When evaluating identical application packages, male and female University psychology professors preferred 2:1 to hire "Brian” over "Karen” as an assistant professor. When evaluating a more experienced record (at the point of promotion to tenure), reservations were expressed four times more often when the name was female. This unconscious bias has a repeated negative effect on Karen's career. This talk will introduce the concept of unconscious bias and also give recommendations on how to address it using an example for a faculty search committee. The process of eliminating unconscious bias begins with awareness, then moves to policy and practice, and ends with accountability.

  18. The effect of Arabian Sea optical properties on SST biases and the South Asian summer monsoon in a coupled GCM

    Energy Technology Data Exchange (ETDEWEB)

    Turner, A.G.; Joshi, M.; Robertson, E.S.; Woolnough, S.J. [University of Reading, NCAS-Climate, Walker Institute for Climate System Research, Department of Meteorology, Reading (United Kingdom)

    2012-08-15

    This study examines the effect of seasonally varying chlorophyll on the climate of the Arabian Sea and South Asian monsoon. The effect of such seasonality on the radiative properties of the upper ocean is often a missing process in coupled general circulation models and its large amplitude in the region makes it a pertinent choice for study to determine any impact on systematic biases in the mean and seasonality of the Arabian Sea. In this study we examine the effects of incorporating a seasonal cycle in chlorophyll due to phytoplankton blooms in the UK Met Office coupled atmosphere-ocean GCM HadCM3. This is achieved by performing experiments in which the optical properties of water in the Arabian Sea - a key signal of the semi-annual cycle of phytoplankton blooms in the region - are calculated from a chlorophyll climatology derived from Sea-viewing Wide Field-of-View Sensor (SeaWiFS) data. The SeaWiFS chlorophyll is prescribed in annual mean and seasonally-varying experiments. In response to the chlorophyll bloom in late spring, biases in mixed layer depth are reduced by up to 50% and the surface is warmed, leading to increases in monsoon rainfall during the onset period. However when the monsoons are fully established in boreal winter and summer and there are strong surface winds and a deep mixed layer, biases in the mixed layer depth are reduced but the surface undergoes cooling. The seasonality of the response of SST to chlorophyll is found to depend on the relative depth of the mixed layer to that of the anomalous penetration depth of solar fluxes. Thus the inclusion of the effects of chlorophyll on radiative properties of the upper ocean acts to reduce biases in mixed layer depth and increase seasonality in SST. (orig.)

  19. Influence of effective stress on swelling pressure of expansive soils

    Directory of Open Access Journals (Sweden)

    Baille Wiebke

    2016-01-01

    Full Text Available The volume change and shear strength behaviour of soils are controlled by the effective stress. Recent advances in unsaturated soil mechanics have shown that the effective stress as applicable to unsaturated soils is equal to the difference between the externally applied stress and the suction stress. The latter can be established based on the soil-water characteristic curve (SWCC of the soil. In the present study, the evolution of swelling pressure in compacted bentonite-sand mixtures was investigated. Comparisons were made between magnitudes of applied suction, suction stress, and swelling pressure.

  20. Stress effects on mood, HPA axis, and autonomic response: comparison of three psychosocial stress paradigms.

    Science.gov (United States)

    Giles, Grace E; Mahoney, Caroline R; Brunyé, Tad T; Taylor, Holly A; Kanarek, Robin B

    2014-01-01

    Extensive experimental psychology research has attempted to parse the complex relationship between psychosocial stress, mood, cognitive performance, and physiological changes. To do so, it is necessary to have effective, validated methods to experimentally induce psychosocial stress. The Trier Social Stress Test (TSST) is the most commonly used method of experimentally inducing psychosocial stress, but it is resource intensive. Less resource intense psychosocial stress tasks include the Socially Evaluative Cold Pressor Task (SECPT) and a computerized mental arithmetic task (MAT). These tasks effectively produce a physiological and psychological stress response and have the benefits of requiring fewer experimenters and affording data collection from multiple participants simultaneously. The objective of this study was to compare the magnitude and duration of these three experimental psychosocial stress induction paradigms. On each of four separate days, participants completed either a control non-stressful task or one of the three experimental stressors: the TSST, SECPT, or MAT. We measured mood, working memory performance, salivary cortisol and alpha-amylase (AA), and heart rate. The TSST and SECPT exerted the most robust effects on mood and physiological measures. TSST effects were generally evident immediately post-stress as well as 10- and 20-minutes after stress cessation, whereas SECPT effects were generally limited to the duration of the stressor. The stress duration is a key determinant when planning a study that utilizes an experimental stressor, as researchers may be interested in collecting dependent measures prior to stress cessation. In this way, the TSST would allow the investigator a longer window to administer tasks of interest.

  1. Stress effects on mood, HPA axis, and autonomic response: comparison of three psychosocial stress paradigms.

    Directory of Open Access Journals (Sweden)

    Grace E Giles

    Full Text Available Extensive experimental psychology research has attempted to parse the complex relationship between psychosocial stress, mood, cognitive performance, and physiological changes. To do so, it is necessary to have effective, validated methods to experimentally induce psychosocial stress. The Trier Social Stress Test (TSST is the most commonly used method of experimentally inducing psychosocial stress, but it is resource intensive. Less resource intense psychosocial stress tasks include the Socially Evaluative Cold Pressor Task (SECPT and a computerized mental arithmetic task (MAT. These tasks effectively produce a physiological and psychological stress response and have the benefits of requiring fewer experimenters and affording data collection from multiple participants simultaneously. The objective of this study was to compare the magnitude and duration of these three experimental psychosocial stress induction paradigms. On each of four separate days, participants completed either a control non-stressful task or one of the three experimental stressors: the TSST, SECPT, or MAT. We measured mood, working memory performance, salivary cortisol and alpha-amylase (AA, and heart rate. The TSST and SECPT exerted the most robust effects on mood and physiological measures. TSST effects were generally evident immediately post-stress as well as 10- and 20-minutes after stress cessation, whereas SECPT effects were generally limited to the duration of the stressor. The stress duration is a key determinant when planning a study that utilizes an experimental stressor, as researchers may be interested in collecting dependent measures prior to stress cessation. In this way, the TSST would allow the investigator a longer window to administer tasks of interest.

  2. Origin of the exchange bias training effects in magnetically coupled soft/hard synthetic bilayers at low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Yalçın, Orhan, E-mail: o.yalcin@nigde.edu.tr [Department of Physics, Niğde University, 51240 Niğde (Turkey); Ünlüer, Şahin [Institute of Sciences, Niğde University, 51240 Niğde (Turkey); Kazan, Sinan [Department of Physics, Gebze Technical University, 41400 Gebze, Kocaeli (Turkey); Şahingöz, Recep [Department of Physics, Bozok University, 66500 Yozgat (Turkey)

    2015-02-15

    Hysteresis loops of the nanoscale magnetic layer Co{sub 90}Fe{sub 10} and Ni{sub 81}Fe{sub 19} and bilayer Co{sub 90}Fe{sub 10}/Ni{sub 81}Fe{sub 19} and Ni{sub 81}Fe{sub 19}/Co{sub 90}Fe{sub 10} films were measured as a function of external dc magnetic field and the thickness dependence of these films were plotted as a function of temperature. Time evolution of the minor/middle/major hysteresis loops of 5/5 nm-thick Ni{sub 81}Fe{sub 19}/Co{sub 90}Fe{sub 10} monolayer have been observed at 10 K. The spin valve, exchange bias training and Barkhausen effects for magnetic layer and bilayer films have been analysed at various temperatures, thicknesses and different orientations according to the substrate. The exchange-bias training effects have been observed only in positive magnetization region. Origin of the exchange-bias training effects and asymmetric hysteresis loops are related to the relaxation mechanism of a pinning layer in magnetically coupled soft/hard bilayers.

  3. Measuring agricultural policy bias

    DEFF Research Database (Denmark)

    Jensen, Henning Tarp; Robinson, Sherman; Tarp, Finn

    2010-01-01

    that the agricultural price incentive bias generally perceived to exist during the 1980s was largely eliminated during the 1990s. Results also demonstrate that general equilibrium effects and country-specific characteristics are crucial for determining the sign and magnitude of agricultural bias. Our comprehensive...... protection measure is therefore uniquely suited to capture the full impact of trade policies on relative agricultural price incentives....

  4. Experimental Modification of Interpretation Bias about Animal Fear in Young Children: Effects on Cognition, Avoidance Behavior, Anxiety Vulnerability, and Physiological Responding

    Science.gov (United States)

    Lester, Kathryn J.; Field, Andy P.; Muris, Peter

    2011-01-01

    This study investigated the effects of experimentally modifying interpretation biases for children's cognitions, avoidance behavior, anxiety vulnerability, and physiological responding. Sixty-seven children (6-11 years) were randomly assigned to receive a positive or negative interpretation bias modification procedure to induce interpretation…

  5. Leakage current conduction, hole injection, and time-dependent dielectric breakdown of n-4H-SiC MOS capacitors during positive bias temperature stress

    Science.gov (United States)

    Samanta, Piyas; Mandal, Krishna C.

    2017-01-01

    The conduction mechanism(s) of gate leakage current JG through thermally grown silicon dioxide (SiO2) films on the silicon (Si) face of n-type 4H-silicon carbide (4H-SiC) has been studied in detail under positive gate bias. It was observed that at an oxide field above 5 MV/cm, the leakage current measured up to 303 °C can be explained by Fowler-Nordheim (FN) tunneling of electrons from the accumulated n-4H-SiC and Poole-Frenkel (PF) emission of trapped electrons from the localized neutral traps located at ≈2.5 eV below the SiO2 conduction band. However, the PF emission current IPF dominates the FN electron tunneling current IFN at oxide electric fields Eox between 5 and 10 MV/cm and in the temperature ranging from 31 to 303 °C. In addition, we have presented a comprehensive analysis of injection of holes and their subsequent trapping into as-grown oxide traps eventually leading to time-dependent dielectric breakdown during electron injection under positive bias temperature stress (PBTS) in n-4H-SiC metal-oxide-silicon carbide structures. Holes were generated in the heavily doped n-type polycrystalline silicon (n+-polySi) gate (anode) as well as in the oxide bulk via band-to-band ionization by the hot-electrons depending on their energy and SiO2 film thickness at Eox between 6 and 10 MV/cm (prior to the intrinsic oxide breakdown field). Transport of hot electrons emitted via both FN and PF mechanisms was taken into account. On the premise of the hole-induced oxide breakdown model, the time- and charge-to-breakdown ( tBD and QBD ) of 8.5 to 47 nm-thick SiO2 films on n-4H-SiC were estimated at a wide range of temperatures. tBD follows the Arrhenius law with activation energies varying inversely with initial applied constant field Eox supporting the reciprocal field ( 1 /E ) model of breakdown irrespective of SiO2 film thicknesses. We obtained an excellent margin (6.66 to 6.33 MV/cm at 31 °C and 5.11 to 4.55 MV/cm at 303 °C) of normal operating field for a 10

  6. Bioinjection treatment: effects of post-injection residual stress on left ventricular wall stress.

    Science.gov (United States)

    Lee, Lik Chuan; Wall, Samuel T; Genet, Martin; Hinson, Andy; Guccione, Julius M

    2014-09-22

    Injection of biomaterials into diseased myocardium has been associated with decreased myofiber stress, restored left ventricular (LV) geometry and improved LV function. However, its exact mechanism(s) of action remained unclear. In this work, we present the first patient-specific computational model of biomaterial injection that accounts for the possibility of residual strain and stress introduced by this treatment. We show that the presence of residual stress can create more heterogeneous regional myofiber stress and strain fields. Our simulation results show that the treatment generates low stress and stretch areas between injection sites, and high stress and stretch areas between the injections and both the endocardium and epicardium. Globally, these local changes are translated into an increase in average myofiber stress and its standard deviation (from 6.9 ± 4.6 to 11.2 ± 48.8 kPa and 30 ± 15 to 35.1 ± 50.9 kPa at end-diastole and end-systole, respectively). We also show that the myofiber stress field is sensitive to the void-to-size ratio. For a constant void size, the myofiber stress field became less heterogeneous with decreasing injection volume. These results suggest that the residual stress and strain possibly generated by biomaterial injection treatment can have large effects on the regional myocardial stress and strain fields, which may be important in the remodeling process.

  7. Sampling Soil CO2 for Isotopic Flux Partitioning: Non Steady State Effects and Methodological Biases

    Science.gov (United States)

    Snell, H. S. K.; Robinson, D.; Midwood, A. J.

    2014-12-01

    Measurements of δ13C of soil CO2 are used to partition the surface flux into autotrophic and heterotrophic components. Models predict that the δ13CO2 of the soil efflux is perturbed by non-steady state (NSS) diffusive conditions. These could be large enough to render δ13CO2 unsuitable for accurate flux partitioning. Field studies sometimes find correlations between efflux δ13CO2 and flux or temperature, or that efflux δ13CO2 is not correlated as expected with biological drivers. We tested whether NSS effects in semi-natural soil were comparable with those predicted. We compared chamber designs and their sensitivity to changes in efflux δ13CO2. In a natural soil mesocosm, we controlled temperature to generate NSS conditions of CO2 production. We measured the δ13C of soil CO2 using in situ probes to sample the subsurface, and dynamic and forced-diffusion chambers to sample the surface efflux. Over eight hours we raised soil temperature by 4.5 OC to increase microbial respiration. Subsurface CO2 concentration doubled, surface efflux became 13C-depleted by 1 ‰ and subsurface CO2 became 13C-enriched by around 2 ‰. Opposite changes occurred when temperature was lowered and CO2 production was decreasing. Different chamber designs had inherent biases but all detected similar changes in efflux δ13CO2, which were comparable to those predicted. Measurements using dynamic chambers were more 13C-enriched than expected, probably due to advection of CO2 into the chamber. In the mesocosm soil, δ13CO2 of both efflux and subsurface was determined by physical processes of CO2 production and diffusion. Steady state conditions are unlikely to prevail in the field, so spot measurements of δ13CO2 and assumptions based on the theoretical 4.4 ‰ diffusive fractionation will not be accurate for estimating source δ13CO2. Continuous measurements could be integrated over a period suitable to reduce the influence of transient NSS conditions. It will be difficult to disentangle

  8. When does stress help or harm? The effects of stress controllability and subjective stress response on Stroop performance.

    Directory of Open Access Journals (Sweden)

    Roselinde Kaiser Henderson

    2012-06-01

    Full Text Available The ability to engage in goal-directed behavior despite exposure to stress is critical to resilience. Questions of how stress can impair or improve behavioral functioning are important in diverse settings, from athletic competitions to academic testing to clinical therapy. Previous research suggests that controllability is a key factor in the impact of stress on behavior: learning how to control stressors buffers people from the negative effects of stress on subsequent cognitively demanding tasks. In addition, research suggests that the impact of stress on cognitive functioning depends on an individual’s response to stressors: moderate responses to stress can lead to improved performance while extreme (high or low responses can lead to impaired performance. The present studies tested the hypothesis that 1 learning to behaviorally control stressors leads to improved performance on a test of general executive functioning, the color-word Stroop, and that 2 this improvement emerges specifically for people who report moderate (subjective responses to stress. Experiment 1: Stroop performance, measured before and after a stress manipulation, was compared across groups of undergraduate participants (n=109. People who learned to control a noise stressor and received accurate performance feedback demonstrated reduced Stroop interference compared with people exposed to uncontrollable noise stress and feedback indicating an exaggerated rate of failure. In the group who learned behavioral control, those who reported moderate levels of stress showed the greatest reduction in Stroop interference. In contrast, in the group exposed to uncontrollable events, self-reported stress failed to predict performance. Experiment 2: In a second sample (n=90, we specifically investigated the role of controllability by keeping the rate of failure feedback constant across groups. In the group who learned behavioral control, those who reported moderate levels of stress

  9. The Effects of Heat Stress on Job Satisfaction, Job Performance and Occupational Stress in Casting Workers

    Directory of Open Access Journals (Sweden)

    Dehghan

    2016-06-01

    Full Text Available Background Job satisfaction, job performance, job stress and heat stress affect the productivity of workers. Objectives This research aimed to study the relationship between heat stress indices with job satisfaction, job performance and job stress in casting workers. Patients and Methods This descriptive-analytical cross sectional survey was performed during summer 2013 on one hundred casting workers. Data were collected by questionnaires of occupational stress, job satisfaction and job performance. Heat stress was measured by the Wet Bulb Globe Temperature (WBGT and Heat Strain Score Index (HSSI questionnaire. The data were analyzed using correlation coefficient by the SPSS16 software. Results The results showed that job satisfaction had a negative correlation with WBGT index (R = -0.42, P < 0.001 and HSSI (R = -0.49, P < 0.001. Also, there was no statistical correlation among occupational stress and job performance with heat stress indices. Conclusions The present study showed that heat stress had a negative effect on job satisfaction; also there were no significant effects on job stress and job performance.

  10. Effect of alcohol on risk of coronary heart disease and stroke: causality, bias, or a bit of both?

    Directory of Open Access Journals (Sweden)

    Jonathan R Emberson

    2006-09-01

    Full Text Available Jonathan R Emberson, Derrick A BennettClinical Trial Service Unit, Richard Doll Building, University of Oxford, Oxford, UKAbstract: Epidemiological studies of middle-aged populations generally find the relationship between alcohol intake and the risk of coronary heart disease (CHD and stroke to be either U- or J-shaped. This review describes the extent that these relationships are likely to be causal, and the extent that they may be due to specific methodological weaknesses in epidemiological studies. The consistency in the vascular benefit associated with moderate drinking (compared with non-drinking observed across different studies, together with the existence of credible biological pathways, strongly suggests that at least some of this benefit is real. However, because of biases introduced by: choice of reference categories; reverse causality bias; variations in alcohol intake over time; and confounding, some of it is likely to be an artefact. For heavy drinking, different study biases have the potential to act in opposing directions, and as such, the true effects of heavy drinking on vascular risk are uncertain. However, because of the known harmful effects of heavy drinking on non-vascular mortality, the problem is an academic one. Studies of the effects of alcohol consumption on health outcomes should recognise the methodological biases they are likely to face, and design, analyse and interpret their studies accordingly. While regular moderate alcohol consumption during middle-age probably does reduce vascular risk, care should be taken when making general recommendations about safe levels of alcohol intake. In particular, it is likely that any promotion of alcohol for health reasons would do substantially more harm than good. Keywords: alcohol, coronary heart disease, stroke

  11. EFFECT OF WORKPLACE STRESS ON JOB PERFORMANCE

    Directory of Open Access Journals (Sweden)

    Azman Ismail

    2015-05-01

    Full Text Available The study examines the relationship between workplace stress and job performance. A survey method was employed to gather self-administered questionnaires from executive and non-executive employees of a leading private investment bank in Peninsular Malaysia. The outcomes of SmartPLS path model analysis of the data showed two important findings: firstly, physiological stress was positively and significantly correlated with job performance. Secondly, psychological stress was positively and significantly correlated with job performance. This finding reveals that physiological and psychological stresses act as important predictors of job performance in the studied organization. The paper provides discussion, implications and conclusion.

  12. Effects of Voltage-Bias Annealing on Metastable Defect Populations in CIGS and CZTSe Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Harvey, Steven P.; Johnston, Steve; Teeter, Glenn

    2016-11-21

    We report on voltage-bias annealing (VBA) experiments performed on CIGS and CZTSe solar cells. In these experiments, completed devices were annealed at moderate temperatures and subsequently quenched with continuously applied voltage bias. These treatments resulted in substantial reversible changes in device characteristics. Photovoltaic (PV) conversion efficiency of the CIGS device varied from below 3% to above 15%, with corresponding changes in CIGS hole density from ~1014 cm-3 to ~1017 cm-3. In the CZTSe device, open-circuit voltage varied from 289 meV to 446 meV, caused by an approximately factor of fifty change in the CZTSe hole density. We interpret these findings in terms of reversible changes to the metastable point-defect populations that control key properties in these materials. Implications for optimization of PV materials and connections to long-term stability of PV devices are discussed.

  13. Effects of self-enhancement bias on perception of supervisory feedback in counseling.

    Science.gov (United States)

    Sohn, Nan Hee

    2009-12-01

    The purpose of this study was to assess how the self-enhancement bias of beginning counselors affects their perceptions of negative feedback in counseling supervision. It was predicted that the self-enhancement bias of beginning counselors would help lower the perceived threat of a counseling supervision, and lower perceived threat would mediate positive interpretation of the feedback in a negative feedback condition. In Korea, 203 volunteer beginning counselors (M = 30.2 yr., SD = 6.7) were shown a videotaped counseling supervision session in which a counseling supervisor delivered either largely positive or largely negative feedback to a beginning counselor. After viewing the tape, these beginning counselors rated their perceptions of the supervision setting and feedback as ego-threatening. Results were consistent with predictions.

  14. Effects of model chemistry and data biases on stratospheric ozone assimilation

    Directory of Open Access Journals (Sweden)

    L. Coy

    2007-06-01

    Full Text Available The innovations or observation minus forecast (O–F residuals produced by a data assimilation system provide a convenient metric of evaluating global analyses. In this study, O–F statistics from the Global Ozone Assimilation Testing System (GOATS are used to examine how ozone assimilation products and their associated O–F statistics depend on input data biases and ozone photochemistry parameterizations (OPP. All the GOATS results shown are based on a 6-h forecast and analysis cycle using observations from SBUV/2 (Solar Backscatter UltraViolet instrument-2 during September–October 2002. Results show that zonal mean ozone analyses are more independent of observation biases and drifts when using an OPP, while the mean ozone O–Fs are more sensitive to observation drifts when using an OPP. In addition, SD O–Fs (standard deviations are reduced in the upper stratosphere when using an OPP due to a reduction of forecast model noise and to increased covariance between the forecast model and the observations. Experiments that changed the OPP reference state to match the observations by using an "adaptive" OPP scheme reduced the mean ozone O–Fs at the expense of zonal mean ozone analyses being more susceptible to data biases and drifts. Additional experiments showed that the upper boundary of the ozone DAS can affect the quality of the ozone analysis and therefore should be placed well above (at least a scale height the region of interest.

  15. Loving yourself more than your neighbor: ERPs reveal online effects of a self-positivity bias.

    Science.gov (United States)

    Fields, Eric C; Kuperberg, Gina R

    2015-09-01

    A large body of social psychological research suggests that we think quite positively of ourselves, often unrealistically so. Research on this 'self-positivity bias' has relied mainly on self-report and behavioral measures, but these can suffer from a number of problems including confounds that arise from the desire to present oneself well. What has not been clearly assessed is whether the self-positivity bias influences the processing of incoming information as it unfolds in real time. In this study, we used event-related potentials to address this question. Participants read two-sentence social vignettes that were either self- or other-relevant. Pleasant words in self-relevant contexts evoked a smaller negativity between 300 and 500 ms (the N400 time window) than the same words in other-relevant contexts, suggesting that comprehenders were more likely to expect positive information when a scenario referred to themselves. This finding indicates that the self-positivity bias is available online, acting as a general schema that directly influences real-time comprehension.

  16. Synergistic effect of bias and target currents for magnetron sputtered MoS{sub 2}-Ti composite films

    Energy Technology Data Exchange (ETDEWEB)

    Buelbuel, Ferhat; Efeoglu, Ihsan [Ataturk Univ., Erzurum (Turkey). Dept. of Mechanical Engineering

    2016-07-01

    In terms of modification of the properties of MoS{sub 2}-Ti composite films, especially tribological properties, significant advances have recently been recorded. However, the commercially production of MoS{sub 2}-Ti composite films is still limited, because the production of desirable MoS{sub 2}-Ti composite coating is only possible by using closed field unbalanced magnetron systems and by the selection of convenient deposition parameters. This requirement has focused the researchers' attention on optimization of deposition parameters. This study is concentrating on the effect of the bias voltage and the target currents for MoS{sub 2}-Ti composite films deposited by pulsed magnetron sputtering (PMS). It is found that the bias and the target currents clearly affect the mechanical, structural and tribological properties of MoS{sub 2}-Ti films.

  17. Correlation of trap states with negative bias thermal illumination stress stabilities in amorphous In-Ga-Zn-O thin-film transistors studied by photoinduced transient spectroscopy

    Science.gov (United States)

    Hayashi, Kazushi; Ochi, Mototaka; Hino, Aya; Tao, Hiroaki; Goto, Hiroshi; Kugimiya, Toshihiro

    2017-03-01

    Negative bias thermal illumination stress (NBTIS) stabilities in amorphous In-Ga-Zn-O (a-IGZO) thin-film transistors (TFTs) were studied by photoinduced transient spectroscopy (PITS). The degradation of TFT performance correlated with trap states in the channel region of a-IGZO TFTs with an etch stop layer (ESL). A prominent peak at approximately 100 K was observed in a-IGZO formed under a partial pressure (p/p) of 4% O2. With increasing O2 p/p, an apparent shoulder of around 230 K appeared in PITS spectra. A higher flow rate of SiH4/N2O for the ESL deposition induced trap states associated with the 230 K peak. The peak at approximately 100 K could originate from the depletion of Zn by preannealing, while the peak at approximately 230 K should be attributed to the oxygen-deficient and/or Zn-rich defects due to the formation of OH in a-IGZO. The trap states in a-IGZO TFTs gave rise to degradation in terms of NBTIS. The threshold voltage shift (ΔV th) was 2.5 V, but it increased with the O2 p/p as well as the flow rate of SiH4/N2O for ESL deposition. The time dependence of ΔV th suggested that hydrogen from the ESL and/or in the a-IGZO thin films was incorporated and modified the trap states in the channel region of the a-IGZO TFTs.

  18. Exchange bias effect in Au-Fe3O4 dumbbell nanoparticles induced by the charge transfer from gold

    Science.gov (United States)

    Feygenson, Mikhail; Bauer, John C.; Gai, Zheng; Marques, Carlos; Aronson, Meigan C.; Teng, Xiaowei; Su, Dong; Stanic, Vesna; Urban, Volker S.; Beyer, Kevin A.; Dai, Sheng

    2015-08-01

    We have studied the origin of the exchange bias effect in the Au-Fe3O4 dumbbell nanoparticles in two samples with different sizes of the Au seed nanoparticles (4.1 and 2.7 nm) and same size of Fe3O4 nanoparticles (9.8 nm). The magnetization, small-angle neutron-scattering, synchrotron x-ray diffraction, and scanning transmission electron microscope measurements determined the antiferromagnetic FeO wüstite phase within Fe3O4 nanoparticles, originating at the interface with the Au nanoparticles. The interface between antiferromagnetic FeO and ferrimagnetic Fe3O4 is giving rise to the exchange bias effect. The strength of the exchange bias fields depends on the interfacial area and lattice mismatch between both phases. We propose that the charge transfer from the Au nanoparticles is responsible for a partial reduction of the Fe3O4 into the FeO phase at the interface with Au nanoparticles. The Au-O bonds are formed, presumably across the interface to accommodate an excess of oxygen released during the reduction of magnetite.

  19. Exchange bias effect in Au-Fe3O4 dumbbell nanoparticles induced by the charge transfer from gold

    Energy Technology Data Exchange (ETDEWEB)

    Feygenson, Mikhail; Bauer, John C.; Gai, Zheng; Marques, Carlos; Aronson, Meigan C.; Teng, Xiaowei; Su, Dong; Stanic, Vesna; Urban, Volker S.; Beyer, Kevin A.; Dai, Sheng

    2015-08-10

    We have studied the origin of the exchange bias effect in the Au-Fe3O4 dumbbell nanoparticles in two samples with different sizes of the Au seed nanoparticles (4.1 and 2.7 nm) and same size of Fe3O4 nanoparticles (9.8 nm). The magnetization, small-angle neutron-scattering, synchrotron x-ray diffraction, and scanning transmission electron microscope measurements determined the antiferromagnetic FeO wustite phase within Fe3O4 nanoparticles, originating at the interface with the Au nanoparticles. The interface between antiferromagnetic FeO and ferrimagnetic Fe3O4 is giving rise to the exchange bias effect. The strength of the exchange bias fields depends on the interfacial area and lattice mismatch between both phases. We propose that the charge transfer from the Au nanoparticles is responsible for a partial reduction of the Fe3O4 into the FeO phase at the interface with Au nanoparticles. The Au-O bonds are formed, presumably across the interface to accommodate an excess of oxygen released during the reduction of magnetite

  20. Are hungry sheep more pessimistic? The effects of food restriction on cognitive bias and the involvement of ghrelin in its regulation.

    Science.gov (United States)

    Verbeek, Else; Ferguson, Drewe; Lee, Caroline

    2014-01-17

    Food restriction is considered to be a welfare issue in extensively reared animals. However, the effects of food restriction on the affective state, and its physiological regulation, are unknown. In Experiment 1, we aimed to assess the effects of increased plasma concentrations of acyl-ghrelin on judgement bias (an indicator of affective states) by fasting sheep for 24h or by ghrelin administration. In Experiment 2, we aimed to assess the effects of chronic food restriction on judgement bias and attention bias towards a food-related cue. For the judgement bias test, sheep were trained in an arena to approach a positive location cue associated with conspecifics and not approach a negative location cue associated with a dog. Three non-trained, non-reinforced ambiguous location cues were situated between the positive and negative locations. Attention bias towards a food-related cue was assessed by placing an empty food bucket against the wall of the arena halfway between the entry point and the positive location. In Experiment 1, sheep were divided into three treatments; 24h fast, ghrelin administration or control. Judgement bias, locomotor activity and plasma cortisol concentrations were assessed. The ghrelin treated group tended to express a more pessimistic bias compared to the control group (Pbias (Pbias and attention bias towards a food-related cue which may indicate altered affective states of sheep.

  1. Analytical performance specifications for changes in assay biasbias) for data with logarithmic distributions as assessed by effects on reference change values

    DEFF Research Database (Denmark)

    Hyltoft Petersen, Per; Lund, Flemming; Fraser, Callum G;

    2016-01-01

    BACKGROUND: The distributions of within-subject biological variation are usually described as coefficients of variation, as are analytical performance specifications for bias, imprecision and other characteristics. Estimation of specifications required for reference change values is traditionally...... performance specifications for reference change value, with combination of Δbias and CVA based on log-Gaussian distributions of CVI as natural logarithms. The model was tested using plasma prolactin and glucose as examples. RESULTS: Analytical performance specifications for reference change value generated...... using the new model based on log-Gaussian distributions were practically identical with the traditional model based on Gaussian distributions. CONCLUSION: The traditional and simple to apply model used to generate analytical performance specifications for reference change value, based on the use...

  2. Equivalent circuit model of converse magnetoelectric effect for the tri-layer magnetoelectric laminates with thermal and stress loadings

    Science.gov (United States)

    Zhou, Hao-Miao; Li, Meng-Han; Liu, Hui; Cui, Xiao-Le

    2015-12-01

    For the converse magnetoelectric coupling effect of the piezoelectric/magnetostrictive/piezoelectric tri-layer symmetric magnetoelectric laminates, based on the nonlinear thermo-magneto-mechanical constitutive equations of the giant magnetostrictive materials and the thermo-electro-mechanical constitutive equations of the piezoelectric materials, according to Newton's second law and the magnetic circuit theorem, an equivalent circuit is established. Then an expression of the converse magnetoelectric coefficient describing nonlinear thermo-magneto-electro-mechanical coupling is established. The curve of the nonlinear converse magnetoelectric coefficient versus the bias magnetic field, is predicted effectively by the expression, and the predictions are in good agreement with the experimental result both qualitatively and quantitatively. Furthermore, the model can predict the complex influences of the bias magnetic field, the stress and the ambient temperature on the converse magnetoelectric coefficient. It can be found from these predictions that the converse magnetoelectric coefficient decreases with the increasing temperature and increases with the increasing tensile stress. Under the common effect of the ambient temperature and the stress, it is also found that the converse magnetoelectric coefficient changes sharply with the ambient temperature when the tensile stress is applied on the laminates, but it has a good stability of temperature when a large compressive stress is applied. Therefore, this work contributes to the researches on the giant converse magnetoelectric coefficient and the designs of magnetoelectric devices based on the converse magnetoelectric coupling.

  3. Discussion and prediction on decreasing flow stress scale effect

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Based on crystal plasticity theory and surface layer model, relation of flow stress to billet dimension and grain size was built,and rationality of derived relation was verified with tensile tests of different size billets. With derived expressions, relation of decreasing flow stress scale effect to billet dimension, grain size as well as billet shape was discussed and predicted. The results show that flow stress is proportional to billet size; with decrease of grain size, flow stress is less influenced by billet dimension. When both cross section area and grain size are same, flow stress decrease of rectangular section billet or sheet is larger than that of circular section billet.

  4. Comment on “Models of stochastic, spatially varying stress in the crust compatible with focal‐mechanism data, and how stress inversions can be biased toward the stress rate” by Deborah Elaine Smith and Thomas H. Heaton

    Science.gov (United States)

    Hardebeck, Jeanne L.

    2015-01-01

    Smith and Heaton (2011) propose a model in which stress in the crust is fractal‐like and highly variable on a range of length scales, including short length‐scales of ~1 km. Smith and Heaton (2011) motivate the need for stress heterogeneity on short length‐scales by citing observations such as short length‐scale changes in stress directions inferred from borehole breakouts, short length‐scale changes in earthquake slip, and the success of numerical models that include short‐wavelength stress heterogeneity. The heterogeneous part of the stress field in their model is more than twice as large as the homogeneous part. The stress field in this model frequently reverses itself over short distances, as can be seen in figure14 a of Smith and Heaton (2011). The modeled stress field contains at least 10 areas of reversed shear stress direction over the length of a 100 km long profile, with the length of the reversed areas ranging from <1 to ~5 km.

  5. Effective Stress Management: A Model of Emotional Intelligence, Self-Leadership, and Student Stress Coping

    Science.gov (United States)

    Houghton, Jeffery D.; Wu, Jinpei; Godwin, Jeffrey L.; Neck, Christopher P.; Manz, Charles C.

    2012-01-01

    This article develops and presents a model of the relationships among emotional intelligence, self-leadership, and stress coping among management students. In short, the authors' model suggests that effective emotion regulation and self-leadership, as mediated through positive affect and self-efficacy, has the potential to facilitate stress coping…

  6. Low-stress and high-stress singing have contrasting effects on glucocorticoid response

    Directory of Open Access Journals (Sweden)

    Daisy eFancourt

    2015-09-01

    Full Text Available Performing music in public is widely recognised as a potentially stress-inducing activity. However, despite the interest in music performance as an acute psychosocial stressor, there has been relatively little research on the effects of public performance on the endocrine system. This study examined the impact of singing in a low-stress performance situation and a high-stress live concert on levels of glucocorticoids (cortisol and cortisone in 15 professional singers. The results showed a significant decrease in both cortisol and cortisone across the low-stress condition, suggesting that singing in itself is a stress-reducing (and possibly health-promoting activity, but significant increases across the high-stress condition. This is the first study to demonstrate that singing affects glucocorticoid responses and that these responses are modulated by the conditions of performance.

  7. Abnormal positive bias stress instability of In–Ga–Zn–O thin-film transistors with low-temperature Al{sub 2}O{sub 3} gate dielectric

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Yu-Hong; Yu, Ming-Jiue; Lin, Ruei-Ping; Hsu, Chih-Pin; Hou, Tuo-Hung, E-mail: thhou@mail.nctu.edu.tw [Department of Electronics Engineering and Institute of Electronics, National Chiao Tung University, Hsinchu, Taiwan (China)

    2016-01-18

    Low-temperature atomic layer deposition (ALD) was employed to deposit Al{sub 2}O{sub 3} as a gate dielectric in amorphous In–Ga–Zn–O thin-film transistors fabricated at temperatures below 120 °C. The devices exhibited a negligible threshold voltage shift (ΔV{sub T}) during negative bias stress, but a more pronounced ΔV{sub T} under positive bias stress with a characteristic turnaround behavior from a positive ΔV{sub T} to a negative ΔV{sub T}. This abnormal positive bias instability is explained using a two-process model, including both electron trapping and hydrogen release and migration. Electron trapping induces the initial positive ΔV{sub T}, which can be fitted using the stretched exponential function. The breakage of residual AlO-H bonds in low-temperature ALD Al{sub 2}O{sub 3} is triggered by the energetic channel electrons. The hydrogen atoms then diffuse toward the In–Ga–Zn–O channel and induce the negative ΔV{sub T} through electron doping with power-law time dependence. A rapid partial recovery of the negative ΔV{sub T} after stress is also observed during relaxation.

  8. Effects of orthostasis on endocrine responses to psychosocial stress.

    Science.gov (United States)

    Nater, Urs M; Ditzen, Beate; Strahler, Jana; Ehlert, Ulrike

    2013-12-01

    Standardized psychological procedures have been designed to induce physiological stress responses. However, the impact of standing (orthostasis) on the physiological reaction after psychological stress remains unclear. The purpose of the current analysis was to examine and quantify the relative contribution of orthostasis to the physiological stress response by comparing a "standing with stress" to a "standing without stress" condition. We investigated the effect of standing with and without stress on responses of the sympathetic-adrenomedullary (SAM) system and the hypothalamic-pituitary-adrenal (HPA) axis using a standardized psychosocial stress protocol (Trier Social Stress Test) and a non-stress condition in a repeated measures design. Subjects (N=30) were exposed to both conditions in randomized order and had to maintain a standing, upright position for 10minutes. In the "standing with stress" condition, significant increases in repeatedly assessed plasma norepinephrine (NE) and epinephrine (EP), as well as in saliva cortisol were found, while in the "standing without stress" condition, no significant changes in plasma epinephrine and saliva cortisol were observed. Calculations of the relative contribution of orthostasis to physiological stress responses revealed that 25.61% of the NE increase, 82.94% of the EP increase, and 68.91% of the cortisol increase, could be attributed to psychosocial stress adjusted for the effects of orthostasis and basal endocrine output. Although these results are indicative for a marked endocrine reaction that is caused by psychosocial stress alone, our findings show that the contribution of orthostasis must be taken into account when interpreting endocrine data collected in a psychosocial stress test.

  9. Fearful faces drive gaze-cueing and threat bias effects in children on the lookout for danger.

    Science.gov (United States)

    Dawel, Amy; Palermo, Romina; O'Kearney, Richard; Irons, Jessica; McKone, Elinor

    2015-03-01

    Most developmental studies of face emotion processing show faces in isolation, in the absence of any broader context. Here we investigate two types of interactions between expression and threat contexts. First, in adults, following of another person's direction of social attention is increased when that person shows fear and the context requires vigilance for danger. We investigate whether this also occurs in children. Using a Posner-style eye-gaze cueing paradigm, we tested whether children would show greater gaze-cueing from fearful than happy expressions when the task was to be vigilant for possible dangerous animals. Testing across the 8-12-year-old age range, we found this fear priority effect was absent in the youngest children but developed to reach adult levels in the oldest children. However, even the oldest children were unable to sustain fear-prioritization when the onset of the target was delayed. Second, we addressed the development of 'threat bias' - namely faster identification of dangerous animals than safe animals - in the social context provided by expressive faces. In our non-anxious samples (i.e. with typical-population levels of anxiety), adults showed a threat bias regardless of the expression or looking direction of the just-seen cue face whereas 8-12-year-olds only showed a threat bias when the just-seen cue face displayed fear. Overall, the results argue that some, but not all, aspects of expression-context interactions are mature by 12 years of age.

  10. Effect of bias voltage on TiAlSiN nanocomposite coatings deposited by HiPIMS

    Science.gov (United States)

    Ma, Quansheng; Li, Liuhe; Xu, Ye; Gu, Jiabin; Wang, Lei; Xu, Yi

    2017-01-01

    TiAlSiN nanocomposite coatings were deposited onto cemented carbide (WC-10 wt.%, Co) substrates by high power impulse magnetron sputtering (HiPIMS). The effect of substrate bias voltage on plasma discharge characterization of HiPIMS, element concentration, deposition rate, microstructure, surface/cross-sectional morphology, hardness and adhesion strength of coatings were studied. Compared with those deposited with direct current magnetic sputtering (DCMS), HiPIMS-deposited TiAlSiN coatings show improvements in some properties, including the surface roughness, the grain size, the hardness and adhesion strength, but a decrease in the deposition rate. When the bias voltage increases, the discharge current rose up from 118A to 165A. HiPIMS-deposited TiAlSiN coatings show a shift of the preferred crystallographic orientation from (220) to (200) and decreases in surface roughness from 14.1 nm down to 7.4 nm and grain size from 10.5 nm to 7.4 nm. Meanwhile, a change in crystal morphology from columnar to equiaxial and a grain refinement, as well as an increase of hardness from 30 GPa up to 42 GPa of those TiAlSiN coatings were observed with the increasing bias voltage and a decrease in adhesion strength from HF2 to HF5 of those coatings were revealed by indentation adhesion test.

  11. Effects of controllable vs. uncontrollable stress on circadian temperature rhythms.

    Science.gov (United States)

    Kant, G J; Bauman, R A; Pastel, R H; Myatt, C A; Closser-Gomez, E; D'Angelo, C P

    1991-03-01

    The effects of sustained stress on body temperature were investigated in rats implanted with mini-transmitters that permitted remote measurement of body temperature. Temperature was first monitored during control conditions. Following the control period, rats were either shaped to avoid/escape signalled around-the-clock intermittent footshock (controllable stress) or yoked to the controlling rats such that the controlling rat and the yoked rat received shock of the same duration, but only the controlling rat could terminate shock by pulling a ceiling chain. Under control conditions, rats demonstrated regular rhythms in body temperature which averaged 1 degree higher during the 12-h dark cycle than the light cycle. Stress disrupted the rhythm and markedly decreased the night-day difference in temperature, especially in the yoked rats in which almost no difference between light and dark cycle temperature was seen. The disruption was most marked for the first days of stress. A regular temperature rhythm was reestablished following about 5 days of stress although the stress condition continued. Leverpressing for food was also affected by the stress conditions with both stress groups leverpressing less than controls and the uncontrollable stress group pressing less than the controllable stress group. These data offer additional evidence of the increased pathophysiological effects of uncontrollable as compared to controllable stress.

  12. Effect of residual internal stresses in tin coatings on specific losses in anisotropic electrical steel

    Science.gov (United States)

    Solov'ev, A. A.; Sochugov, N. S.; Oskomov, K. V.

    2010-02-01

    Methods of X-ray diffraction analysis, mass-spectrometry, and atomic force microscopy have been used to perform a comparative analysis of factors that cause the appearance of residual stresses in TiN coatings deposited by reactive magnetron sputtering and to study their effect on specific magnetic losses in electrical-sheet steel. Physical and mechanical parameters of coatings, such as hardness, elastic modulus, residual stress, microstructure, and surface morphology, have been studied. It has been shown that the level of internal stresses in a coating depends on its thickness and increases with increasing quantity and energy of ions in the deposited beam. The maximum magnitudes of compressive stresses in coatings (13 GPa) were obtained when using an unbalanced working regime of the magnetron and a negative bias at the substrate. The hardness of coatings produced under such conditions reaches 29 GPa. There has been demonstrated a possibility of reducing losses in electrical-sheet steels by about 15% by depositing surface coatings with high compressive stresses.

  13. Embodying an outgroup: the role of racial bias and the effect of multisensory processing in somatosensory remapping.

    Science.gov (United States)

    Fini, Chiara; Cardini, Flavia; Tajadura-Jiménez, Ana; Serino, Andrea; Tsakiris, Manos

    2013-01-01

    We come to understand other people's physical and mental states by re-mapping their bodily states onto our sensorimotor system. This process, also called somatosensory resonance, is an essential ability for social cognition and is stronger when observing ingroup than outgroup members. Here we investigated, first, whether implicit racial bias constrains somatosensory resonance, and second, whether increasing the ingroup/outgroup perceived physical similarity results in an increase in the somatosensory resonance for outgroup members. We used the Visual Remapping of Touch effect as an index of individuals' ability in resonating with the others, and the Implicit Association Test to measure racial bias. In Experiment 1, participants were asked to detect near-threshold tactile stimuli delivered to their own face while viewing either an ingroup or an outgroup face receiving a similar stimulation. Our results showed that individuals' tactile accuracy when viewing an outgroup face being touched was negatively correlated to their implicit racial bias. In Experiment 2, participants received the interpersonal multisensory stimulation (IMS) while observing an outgroup member. IMS has been found to increase the perceived physical similarity between the observer's and the observed body. We tested whether such increase in ingroup/outgroup perceived physical similarity increased the remapping ability for outgroup members. We found that after sharing IMS experience with an outgroup member, tactile accuracy when viewing touch on outgroup faces increased. Interestingly, participants with stronger implicit bias against the outgroup showed larger positive change in the remapping. We conclude that shared multisensory experiences might represent one key way to improve our ability to resonate with others by overcoming the boundaries between ingroup and outgroup categories.

  14. Embodying an outgroup: the role of racial bias and the effect of multisensory processing in somatosensory remapping

    Directory of Open Access Journals (Sweden)

    Chiara eFini

    2013-11-01

    Full Text Available We come to understand other people’s physical and mental states by re-mapping their bodily states onto our sensorimotor system. This process, also called somatosensory resonance, is an essential ability for social cognition and is stronger when observing ingroup than outgroup members. Here we investigated, first, whether implicit racial bias constrains somatosensory resonance, and second, whether increasing the ingroup/outgroup perceived physical similarity results in an increase in the somatosensory resonance for outgroup members. We used the Visual Remapping of Touch effect as an index of individuals’ ability in resonating with the others, and the Implicit Association Test to measure racial bias. In Experiment 1, participants were asked to detect near-threshold tactile stimuli delivered to their own face while viewing either an ingroup or an outgroup face receiving a similar stimulation. Our results showed that individuals’ tactile accuracy when viewing an outgroup face being touched was negatively correlated to their implicit racial bias. In Experiment 2, participants received the Interpersonal Multisensory Stimulation (IMS while observing an outgroup member. IMS has been found to increase the perceived physical similarity between the observer’s and the observed body. We tested whether such increase in ingroup/outgroup perceived physical similarity increased the remapping ability for outgroup members. We found that after sharing IMS experience with an outgroup member, tactile accuracy when viewing touch on outgroup faces increased. Interestingly, participants with stronger implicit bias against the outgroup showed larger positive change in the remapping. We conclude that shared multisensory experiences might represent one key way to improve our ability to resonate with others by overcoming the boundaries between ingroup and outgroup categories.

  15. Overcoming the effects of stress on reactor operator performance

    Energy Technology Data Exchange (ETDEWEB)

    He Xuhong; Wei Li; Zhao Bingquan [Tsinghua Univ., Nuclear Power Plant Simulation Training Center, Beijing (China)

    2003-03-01

    Reactor operators may be exposed to significant levels of stress during plant emergencies and their performance may be affected by the stress. This paper first identified the potential sources of stress in the nuclear power plant, then discussed the ways in which stress is likely to affect the reactor operators, and finally identified several training approaches for reducing or eliminating stress effects. The challenges for effective stress reducing training may seem daunting, yet the challenges are real and must be addressed. This paper reviewed researches in training design, knowledge and skill acquisition, and training transfer point to a number of strategies that can be used to address these challenges and lead to more effective training and development. (author)

  16. DC bias effect on alternating current electrical conductivity of poly(ethylene terephthalate)/alumina nanocomposites

    Science.gov (United States)

    Nikam, Pravin N.; Deshpande, Vineeta D.

    2016-05-01

    Polymer nanocomposites based on metal oxide (ceramic) nanoparticles are a new class of materials with unique properties and designed for various applications such as electronic device packaging, insulation, fabrication and automotive industries. Poly(ethylene terephthalate) (PET)/alumina (Al2O3) nanocomposites with filler content between 1 wt% and 5 wt% were prepared by melt compounding method using co-rotating twin screw extruder and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and precision LCR meter techniques. The results revealed that proper uniform dispersion at lower content up to 2 wt% of nano-alumina observed by using TEM. Aggregation of nanoparticles was observed at higher content of alumina examined by using SEM and TEM. The frequency dependences of the alternating current (AC) conductivity (σAC) of PET/alumina nanocomposites on the filler content and DC bias were investigated in the frequency range of 20Hz - 1MHz. The results showed that the AC and direct current (DC) conductivity increases with increasing DC bias and nano-alumina content upto 3 wt%. It follows the Jonscher's universal power law of solids. It revealed that σAC of PET/alumina nanocomposites can be well characterized by the DC conductivity (σDC), critical frequency (ωc), critical exponent of the power law (s). Roll of DC bias potential led to an increase of DC conductivity (σDC) due to the creation of additional conducting paths with the polymer nanocomposites and percolation behavior achieved through co-continuous morphology.

  17. Contrast-induced nephrotoxicity: possible synergistic effect of stress hyperglycemia.

    LENUS (Irish Health Repository)

    O'Donnell, David H

    2010-07-01

    Oxidative stress on the renal tubules has been implicated as a mechanism of injury in both stress hyperglycemia and contrast-induced nephrotoxicity. The purpose of this study was to determine whether the combination of these effects has a synergistic effect on accentuating renal tubular apoptosis and therefore increasing the risk of contrast-induced nephrotoxicity.

  18. Effect of Thermal Stress on Cardiac Function

    OpenAIRE

    Wilson, Thad E.; Crandall, Craig G.

    2011-01-01

    Whole-body heating decreases pulmonary capillary wedge pressure and cerebral vascular conductance, and causes an inotropic shift in the Frank-Starling curve. Whole-body cooling increases pulmonary capillary wedge pressure and cerebral vascular conductance without changing systolic function. These and other data indicate factors affecting cardiac function may mechanistically contribute to syncope during heat stress and improvements in orthostatic tolerance during cold stress.

  19. Parameter estimation biases due to contributions from the Rees-Sciama effect to the integrated Sachs-Wolfe spectrum

    Science.gov (United States)

    Schäfer, Björn Malte; Kalovidouris, Angelos Fotios; Heisenberg, Lavinia

    2011-09-01

    The subject of this paper is an investigation of the non-linear contributions to the spectrum of the integrated Sachs-Wolfe (iSW) effect. We derive the corrections to the iSW autospectrum and the iSW-tracer cross-spectrum consistently to third order in perturbation theory and analyse the cumulative signal-to-noise ratio for a cross-correlation between the Planck and Euclid data sets as a function of multipole order. We quantify the parameter sensitivity and the statistical error bounds on the cosmological parameters Ωm, σ8, h, ns and w from the linear iSW effect and the systematical parameter estimation bias due to the non-linear corrections in a Fisher formalism, analysing the error budget in its dependence on multipole order. Our results include the following: (i) the spectrum of the non-linear iSW effect can be measured with 0.8σ statistical significance, (ii) non-linear corrections dominate the spectrum starting from ℓ≃ 102, (iii) an anticorrelation of the CMB temperature with tracer density on high multipoles in the non-linear regime, (iv) a much weaker dependence of the non-linear effect on the dark energy model compared to the linear iSW effect and (v) parameter estimation biases amount to less than 0.1σ and weaker than other systematics.

  20. Stretching the Stress Boundary: Linking Air Pollution Health Effects to a Neurohormonal Stress Response

    Science.gov (United States)

    Inhaled pollutants produce effects in virtually all organ systems in our body and have been linked to chronic diseases including hypertension, atherosclerosis, Alzheimer’s and diabetes. A neurohormonal stress response (referred here as a systemic response produced by activ...

  1. Stress and Memory: Behavioral Effects and Neurobiological Mechanisms

    Directory of Open Access Journals (Sweden)

    Carmen Sandi

    2007-01-01

    Full Text Available Stress is a potent modulator of learning and memory processes. Although there have been a few attempts in the literature to explain the diversity of effects (including facilitating, impairing, and lack of effects described for the impact of stress on memory function according to single classification criterion, they have proved insufficient to explain the whole complexity of effects. Here, we review the literature in the field of stress and memory interactions according to five selected classifying factors (source of stress, stressor duration, stressor intensity, stressor timing with regard to memory phase, and learning type in an attempt to develop an integrative model to understand how stress affects memory function. Summarizing on those conditions in which there was enough information, we conclude that high stress levels, whether intrinsic (triggered by the cognitive challenge or extrinsic (induced by conditions completely unrelated to the cognitive task, tend to facilitate Pavlovian conditioning (in a linear-asymptotic manner, while being deleterious for spatial/explicit information processing (which with regard to intrinsic stress levels follows an inverted U-shape effect. Moreover, after reviewing the literature, we conclude that all selected factors are essential to develop an integrative model that defines the outcome of stress effects in memory processes. In parallel, we provide a brief review of the main neurobiological mechanisms proposed to account for the different effects of stress in memory function. Glucocorticoids were found as a common mediating mechanism for both the facilitating and impairing actions of stress in different memory processes and phases. Among the brain regions implicated, the hippocampus, amygdala, and prefrontal cortex were highlighted as critical for the mediation of stress effects.

  2. [STRESS AND INFARCT LIMITING EFFECTS OF EARLY HYPOXIC PRECONDITIONING].

    Science.gov (United States)

    Lishmanov, Yu B; Maslov, L N; Sementsov, A S; Naryzhnaya, N V; Tsibulnikov, S Yu

    2015-09-01

    It was established that early hypoxic preconditioning is an adaptive state different from eustress and distress. Hypoxic preconditioning has the cross effects, increasing the tolerance of the heart to ischemia-reperfusion and providing antiulcerogenic effect during immobilization stress.

  3. Morphologic effects of the stress response in fish.

    Science.gov (United States)

    Harper, Claudia; Wolf, Jeffrey C

    2009-01-01

    Fish and other aquatic animals are subject to a broad variety of stressors because their homeostatic mechanisms are highly dependent on prevailing conditions in their immediate surroundings. Yet few studies have addressed stress as a potential confounding factor for bioassays that use fish as test subjects. Common stressors encountered by captive fish include physical and mental trauma associated with capture, transport, handling, and crowding; malnutrition; variations in water temperature, oxygen, and salinity; and peripheral effects of contaminant exposure or infectious disease. Some stress responses are detectable through gross or microscopic examination of various organs or tissues; as reported in the literature, stress responses are most consistently observed in the gills, liver, skin, and components of the urogenital tract. In addition to presenting examples of various stressors and corresponding morphologic effects, this review highlights certain challenges of evaluating stress in fish: (1) stress is an amorphous term that does not have a consistently applied definition; (2) procedures used to determine or measure stress can be inherently stressful; (3) interactions between stressors and stress responses are highly complex; and (4) morphologically, stress responses are often difficult to distinguish from tissue damage or compensatory adaptations induced specifically by the stressor. Further investigations are necessary to more precisely define the role of stress in the interpretation of fish research results.

  4. The effects of stress on nuclear power plant operational decision making and training approaches to reduce stress effects

    Energy Technology Data Exchange (ETDEWEB)

    Mumaw, R.J.

    1994-08-01

    Operational personnel may be exposed to significant levels of stress during unexpected changes in plant state an plant emergencies. The decision making that identifies operational actions, which is strongly determined by procedures, may be affected by stress, and performance may be impaired. ER report analyzes potential effects of stress in nuclear power plant (NPP) settings, especially in the context of severe accident management (SAM). First, potential sources of stress in the NPP setting are identified. This analysis is followed by a review of the ways in which stress is likely to affect performance, with an emphasis on performance of cognitive skills that are linked to operational decision making. Finally, potential training approaches for reducing or eliminating stress effects are identified. Several training approaches have the potential to eliminate or mitigate stress effects on cognitive skill performance. First, the use of simulated events for training can reduce the novelty and uncertainty that can lead to stress and performance impairments. Second, training to make cognitive processing more efficient and less reliant on attention and memory resources can offset the reductions in these resources that occur under stressful conditions. Third, training that targets crew communications skills can reduce the likelihood that communications will fail under stress.

  5. Large exchange bias effect in LaCr0.9Ru0.1O3

    Science.gov (United States)

    Sarkar, Babusona; Dalal, Biswajit; De, S. K.

    2016-11-01

    The incorporation of tetravalent Ru (10%) into antiferromagnetic spin structure of LaCrO3 leads to mixed valence states of Cr (Cr2+ and Cr3+). Highly delocalized 4d orbital of Ru induces prominent ferromagnetic (FM) component in antiferromagnetic (AFM) matrix of parent compound. The complex magnetic interaction across the interface of FM and AFM regions gives rise to large exchange bias field (HEB) of about 10 kOe. The inverse and normal magnetocaloric effect for magnetic field up to 50 kOe coexists in a single material due to multiple magnetic phase transitions with temperature.

  6. Training Effect and Hysteretic Behaviour of Angular Dependence of Exchange Bias in Co/IrMn Bilayers

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jing; DU Jun; BAI Xiao-Jun; YOU Biao; ZHANG Wei; HU An

    2009-01-01

    @@ The training effect and the hysteresis behaviour of the angular dependence of exchange bias are extensively investigated upon the variation of the IrMn layer thickness tIrMn in a series of Co/IrMn bilayers. When tIrMn is very small, both of them are negligible. Then they increase very sharply with increasing tIrMn and then reach maxima at almost the same value of tIrMn. Finally they both decrease when tIrMn is further increased. The similar variation trends suggest that these phenomena arise from irreversible change of antiferromagnet spin orientations, according to the thermal activation model.

  7. Effect of Surface Topography on Stress Concentration Factor

    Institute of Scientific and Technical Information of China (English)

    CHENG Zhengkun; LIAO Ridong

    2015-01-01

    Neuber rule and Arola-Ramulu model are widely used to predict the stress concentration factor of rough specimens. However, the height parameters and effective valley radius used in these two models depend strongly on the resolution of the roughness-measuring instruments and are easily introduce measuring errors. Besides, it is difficult to find a suitable parameter to characterize surface topography to quantitatively describe its effect on stress concentration factor. In order to overcome these disadvantages, profile moments are carried out to characterize surface topography, surface topography is simulated by superposing series of cosine components, the stress concentration factors of different micro cosine-shaped surface topographies are investigated by finite element analysis. In terms of micro cosine-shaped surface topography, an equation using the second profile moment to estimate the stress concentration factor is proposed, predictions for the stress concentration factor using the proposed expression are within 10% error compared with the results of finite element analysis, which are more accurate than other models. Moreover, the proposed equation is applied to the real surface topography machined by turning. Predictions for the stress concentration factor using the proposed expression are within 10% of the maximum stress concentration factors and about 5% of the effective stress concentration factors estimated from the finite element analysis for three levels of turning surface topographies under different simulated scales. The proposed model is feasible in predicting the stress concentration factors of real machined surface topographies.

  8. Judgement heuristics and bias in evidence interpretation: The effects of computer generated exhibits.

    Science.gov (United States)

    Norris, Gareth

    2015-01-01

    The increasing use of multi-media applications, trial presentation software and computer generated exhibits (CGE) has raised questions as to the potential impact of the use of presentation technology on juror decision making. A significant amount of the commentary on the manner in which CGE exerts legal influence is largely anecdotal; empirical examinations too are often devoid of established theoretical rationalisations. This paper will examine a range of established judgement heuristics (for example, the attribution error, representativeness, simulation), in order to establish their appropriate application for comprehending legal decisions. Analysis of both past cases and empirical studies will highlight the potential for heuristics and biases to be restricted or confounded by the use of CGE. The paper will conclude with some wider discussion on admissibility, access to justice, and emerging issues in the use of multi-media in court.

  9. The Amelia Bedelia effect: world knowledge and the goal bias in language acquisition.

    Science.gov (United States)

    Srinivasan, Mahesh; Barner, David

    2013-09-01

    How does world knowledge interact with syntax to constrain linguistic interpretation? We explored this question by testing children's acquisition of verbs like weed and water, which have opposite meanings despite occurring in the same syntactic frames. Whereas "weed the garden" treats "the garden" as a source, "water the garden" treats it as a goal. In five experiments, we asked how children learn these verbs. Previous theories predict that verbs which describe the transfer of an object with respect to its natural origin (e.g., "weed the garden") should receive source interpretations, whereas verbs that describe the transfer of an object with respect to something it is functionally related to (e.g., "water the garden") should receive goal interpretations. Therefore, acquiring world knowledge - about the natural origins and functional uses of objects - should be sufficient for differentiating between source and goal meanings. Experiments 1 and 2 casted doubt on this hypothesis, as 4- and 5-year-olds failed to use their world knowledge when interpreting these verbs and instead overextended goal interpretations. For example, children interpreted "weed the garden" to mean "put weeds onto a garden", even when they knew the natural origin of weeds. Experiment 3 tested children's interpretation of novel verbs and directly manipulated their access to relevant world knowledge. While younger children continued to exhibit a goal bias and failed to use world knowledge, older children generalized goal and source interpretations to novel verbs according to world knowledge. In Experiments 4 and 5, we confirmed that adults use world knowledge to guide their interpretation of novel verbs, but also showed that even adults prefer goal interpretations when they are made contextually plausible. We argue that children ultimately overcome a goal bias by learning to use their world knowledge to weigh the plausibility of events (e.g., of putting weeds into a garden).

  10. Correcting Bias Caused by Missing Data in the Estimate of the Effect of Apolipoprotein ε4 on Cognitive Decline.

    Science.gov (United States)

    Hall, Charles B; Lipton, Richard B; Katz, Mindy J; Wang, Cuiling

    2015-01-01

    Longitudinal administration of neuropsychological instruments are often used to assess age-related changes in cognition. Informative loss to follow-up may bias the results of these studies. Herein, we use auxiliary data to adjust for informative loss to follow-up. In the Einstein Aging Study, memory was assessed annually in a community sample of adults age 70+, free of dementia at baseline, using the free recall from the Free and Cued Selective Reminding Test, and via telephone using the Memory Impairment Screen for Telephone (the auxiliary data). Joint linear mixed models were used to assess how the effect of the APOE ε4 genotype may be affected by informative missingness in the in-person data. A total of 620 EAS participants contributed 2085 person years of follow-up to the analyses. Memory decline rates estimated in joint models were 19% greater in ε4 negative participants and 27% greater in ε4 positive participants compared to traditional approaches; the effect of APOE ε4 on memory decline was 37% greater. Joint modeling methods can help address bias caused by informative missing data in the estimation of the effect of risk factors on cognitive change, and may be applicable to a broader range of outcomes in longitudinal aging studies.

  11. Effective stress law for the permeability of a limestone

    CERN Document Server

    Ghabezloo, Siavash; Guédon, Sylvine; Martineau, François

    2008-01-01

    The effective stress law for the permeability of a limestone is studied experimentally by performing constant head permeability tests in a triaxial cell with different conditions of confining pressure and pore pressure. Test results have shown that a pore pressure increase and a confining pressure decrease both result in an increase of the permeability, and that the effect of the pore pressure change on the variation of the permeability is more important than the effect of a change of the confining pressure. A power law is proposed for the variation of the permeability with the effective stress. The permeability effective stress coefficient increases linearly with the differential pressure and is greater than one as soon the differential pressure exceeds few bars. The test results are well reproduced using the proposed permeability-effective stress law. A conceptual pore-shell model based on a detailed observation of the microstructure of the studied limestone is proposed. This model is able to explain the ex...

  12. Timing matters: temporal dynamics of stress effects on memory retrieval.

    Science.gov (United States)

    Schwabe, Lars; Wolf, Oliver T

    2014-09-01

    Stress may impair memory retrieval. This retrieval impairment has been attributed to the action of the stress hormone cortisol, which is released with a delay of several minutes after a stressful encounter. Hence, most studies tested memory retrieval 20-30 min after stress, when the stress-induced cortisol increase peaks. In the present experiment, we investigated whether retrieval impairments can also be found at later intervals after stress. To this end, participants learned a list of words on day 1. Twenty-four hours later, they were first exposed to a stressor or a nonstressful control manipulation and completed a recognition test for the words either immediately thereafter, 25 min later, or 90 min later. Our findings showed that stress did not impair memory retrieval when memory was tested immediately after the stressor, before cortisol levels were elevated. However, retrieval performance was impaired 25 min after stress, when cortisol levels peaked, as well as 90 min after the stressor, when cortisol levels had already returned to baseline. The retrieval impairment 90 min after stress appeared to be even stronger than the one after 25 min. These findings suggest that the detrimental effects of stress on retrieval performance may last longer than is usually assumed.

  13. Effect of Huzikang-duannaibao on piglets' ablactation stress

    Institute of Scientific and Technical Information of China (English)

    Zhou Shenglin; Jiang Zhengyun

    2003-01-01

    Piglets' alactation-stress with diarrhea as a main symptom is a serious problem in pig farming. The experiment indicates that the complex premix additive Huzikang-duannaibao can be used to control ablactation-stress syndromes and its effects are better than that of the common antibiotic ligomycin.

  14. THE EFFECTS OF PULSE BIAS VOLTAGE AND N2 PARTIAL PRESSURE ON TiAIN FILMS OF ARC ION PLATING (AIP)

    Institute of Scientific and Technical Information of China (English)

    M.S. Li; S.L. Zhu; Fuhui Wang; C. Sun; L.S. Wen

    2001-01-01

    Owing to the characteristics of arc ion plating(AIP) technique, the structure and com-position of TiAlN films can be tailored by controlling of various parameters such ascompositions of target materials, N2 partial pressure, substrate bias and so on. ln thisstudy, several titanium aluminum nitride films were deposited on 1Cr11Ni2 W2Mo Vsteel for compressor blade of areo-engine under different d.c pulse bias voltage and ni-trogen partial pressure. The effects of substrate pulse bias and nitrogen partial pressureon the deposition rate, droplet formation, microstruture and elemental component ofthe films were investigated.

  15. Effects of Stress and MDMA on Hippocampal Gene Expression

    Directory of Open Access Journals (Sweden)

    Georg F. Weber

    2014-01-01

    Full Text Available MDMA (3,4-methylenedioxymethamphetamine is a substituted amphetamine and popular drug of abuse. Its mood-enhancing short-term effects may prompt its consumption under stress. Clinical studies indicate that MDMA treatment may mitigate the symptoms of stress disorders such as posttraumatic stress syndrome (PTSD. On the other hand, repeated administration of MDMA results in persistent deficits in markers of serotonergic (5-HT nerve terminals that have been viewed as indicative of 5-HT neurotoxicity. Exposure to chronic stress has been shown to augment MDMA-induced 5-HT neurotoxicity. Here, we examine the transcriptional responses in the hippocampus to MDMA treatment of control rats and rats exposed to chronic stress. MDMA altered the expression of genes that regulate unfolded protein binding, protein folding, calmodulin-dependent protein kinase activity, and neuropeptide signaling. In stressed rats, the gene expression profile in response to MDMA was altered to affect sensory processing and responses to tissue damage in nerve sheaths. Subsequent treatment with MDMA also markedly altered the genetic responses to stress such that the stress-induced downregulation of genes related to the circadian rhythm was reversed. The data support the view that MDMA-induced transcriptional responses accompany the persistent effects of this drug on neuronal structure/function. In addition, MDMA treatment alters the stress-induced transcriptional signature.

  16. NEGATIVE EFFECT OF METALLOID STRESS ON WHEAT

    Directory of Open Access Journals (Sweden)

    Marína Maglovski

    2015-02-01

    Full Text Available Arsenic (As belongs to heavy metals and its accumulation in plants, besides damaging the organism itself, represents a potential health risk to animal and human consumers. Therefore, contamination of soils and waters with this compound is a serious environmental problem. In this work we focused on investigating a negative impact of As on selected parameters of growth of wheat plants (Triticum aestivum L. cv. Genoveva grown in hydropony. In the stage of first assimilation leaves we applied a solution of heavy metal (1 mg.kg-1 As3+ on wheat plants. For plants grown under hydropony conditions we observed different plant parameters such as length, weight, amount of fresh and dry biomass. Further we analyzed accumulation of hydrogen peroxide and products membrane lipid peroxidation as indicators of oxidative stress. In addition to these we also measured the content of photosynthetic pigments, maximal quantum yield and proline in plant tissue. Our data indicate reduction of the biomass of shoots forthcoming as a result of exposure of stressed plants to As. Decline of biomass accumulation was accompanied by increase of hydrogen peroxide in plant tissue. In contrast, level of lipid peroxidation was suppressed in stressed shoots. Contents of photosynthetic pigments soundly decreased. Interestingly, fluorescence (Fp=Fm in stressed wheat shoots increased. Similarly in tested shoots the content of proline was increased. The results indicate that the applied dose of As has a negative impact on the growth and photosynthetic performance of stressed plants. A better understanding of the mechanisms responsible for As resistance and toxicity in plants requires further investigation.

  17. The role of attentional bias in the effect of food advertising on actual food intake among children.

    Science.gov (United States)

    Folkvord, Frans; Anschütz, Doeschka J; Wiers, Reinout W; Buijzen, Moniek

    2015-01-01

    This study examined the potential moderating role of attentional bias (i.e., gaze duration, number of fixations, latency of initial fixation) in the effect of advergames promoting energy-dense snacks on children's snack intake. A randomized between-subject design was conducted with 92 children who played an advergame that promoted either energy-dense snacks or nonfood products. Eye movements and reaction times to food and nonfood cues were recorded to assess attentional bias during playtime using eye-tracking methods. Children could eat freely after playing the game. The results showed that playing an advergame containing food cues increased total intake. Furthermore, children with a higher gaze duration for the food cues ate more of the advertised snacks. In addition, children with a faster latency of initial fixation to the food cues ate more in total and ate more of the advertised snacks. The number of fixations on the food cues did not increase actual snack intake. Food advertisements are designed to grab attention, and this study shows that the extent to which a child's attention is directed to a food cue increases the effect of the advertisement.

  18. Cellular effects of swim stress in the dorsal raphe nucleus.

    Science.gov (United States)

    Kirby, Lynn G; Pan, Yu-Zhen; Freeman-Daniels, Emily; Rani, Shobha; Nunan, John D; Akanwa, Adaure; Beck, Sheryl G

    2007-07-01

    Swim stress regulates forebrain 5-hydroxytryptamine (5-HT) release in a complex manner and its effects are initiated in the serotonergic dorsal raphe nucleus (DRN). The purpose of this study was to examine the effects of swim stress on the physiology of DRN neurons in conjunction with 5-HT immunohistochemistry. Basic membrane properties, 5-HT(1A) and 5-HT(1B) receptor-mediated responses and glutamatergic excitatory postsynaptic currents (EPSCs) were measured using whole-cell patch clamp techniques. Rats were forced to swim for 15min and 24h later DRN brain slices were prepared for electrophysiology. Swim stress altered the resting membrane potential, input resistance and action potential duration of DRN neurons in a neurochemical-specific manner. Swim stress selectively elevated glutamate EPSC frequency in 5-HT DRN neurons. Swim stress non-selectively reduced EPSC amplitude in all DRN cells. Swim stress elevated the 5-HT(1B) receptor-mediated inhibition of glutamatergic synaptic activity that selectively targeted 5-HT cells. Non-5-HT DRN neurons appeared to be particularly responsive to the effects of a milder handling stress. Handling elevated EPSC frequency, reduced EPSC decay time and enhanced a 5-HT(1B) receptor-mediated inhibition of mEPSC frequency selectively in non-5-HT DRN cells. These results indicate that swim stress has both direct, i.e., changes in membrane characteristics, and indirect effects, i.e., via glutamatergic afferents, on DRN neurons. These results also indicate that there are distinct local glutamatergic afferents to neurochemically specific populations of DRN neurons, and furthermore that these distinct afferents are differentially regulated by swim stress. These cellular changes may contribute to the complex effects of swim stress on 5-HT neurotransmission and/or the behavioral changes underlying the forced swimming test model of depression.

  19. Exchange bias effect in polycrystalline NiO/NiMn{sub 2}O{sub 4} composite

    Energy Technology Data Exchange (ETDEWEB)

    Freitas Cabral, A.J. [Instituto de Ciências Exatas e Naturais, Universidade Federal do Pará (UFPA), Belém, PA (Brazil); Peña Serna, J.; Rache Salles, B.; Novak, M.A. [Instituto de Física, Universidade Federal do Rio de janeiro (UFRJ), Rio de Janeiro, RJ (Brazil); Pinto, A.L. [Centro Brasileiro de Pesquisas Físicas (CBPF), Rio de Janeiro, RJ (Brazil); Rocha Remédios, C.M. [Instituto de Ciências Exatas e Naturais, Universidade Federal do Pará (UFPA), Belém, PA (Brazil)

    2015-05-05

    Highlights: • Antiferromagnetic NiO/ferrimagnetic NiMn{sub 2}O{sub 4} oxide composites. • Grains are well faceted, indicating that the specimen was well crystallized. • The micrographs suggests that NiO and NiMn{sub 2}O{sub 4} may be stuck to each other. • EB effect in NiO/NiMn{sub 2}O{sub 4} oxide composites. • EB effect increases with the amount of NiO. - Abstract: Calcination of aqueous solutions formed by different molar ratios between the nickel and manganese chlorides led to the formation of antiferromagnetic NiO/ferrimagnetic NiMn{sub 2}O{sub 4} oxide composites, as determined by X-ray powder diffraction technique and Rietveld refinement. Low temperature zero field cooled and field cooled magnetic hysteresis cycles show an exchange bias effect, presumably due to interaction at the interfaces between the antiferromagnetic and ferrimagnetic materials.

  20. Differential effects of stress and glucocorticoids on adult neurogenesis.

    Science.gov (United States)

    Schoenfeld, Timothy J; Gould, Elizabeth

    2013-01-01

    Stress is known to inhibit neuronal growth in the hippocampus. In addition to reducing the size and complexity of the dendritic tree, stress and elevated glucocorticoid levels are known to inhibit adult neurogenesis. Despite the negative effects of stress hormones on progenitor cell proliferation in the hippocampus, some experiences which produce robust increases in glucocorticoid levels actually promote neuronal growth. These experiences, including running, mating, enriched environment living, and intracranial self-stimulation, all share in common a strong hedonic component. Taken together, the findings suggest that rewarding experiences buffer progenitor cells in the dentate gyrus from the negative effects of elevated stress hormones. This chapter considers the evidence that stress and glucocorticoids inhibit neuronal growth along with the paradoxical findings of enhanced neuronal growth under rewarding conditions with a view toward understanding the underlying biological mechanisms.

  1. Residual stresses and their effects in composite laminates

    Science.gov (United States)

    Hahn, H. T.; Hwang, D. G.

    1983-01-01

    Residual stresses in composite laminates are caused by the anisotropy in expansional properties of constituent unidirectional plies. The effect of these residual stresses on dimensional stability is studied through the warping of unsymmetric (0 sub 4/90 sub 4)sub T graphite/epoxy laminates while their effect on ply failure is analyzed for (0/90)sub 2s Kevlar 49/epoxy laminate. The classical laminated plate theory is used to predict the warping of small and large panels. The change of warping does not indicate a noticeable stress relaxation at 75 C while it is very sensitive to moisture content and hence to environment. A prolonged gellation at the initial cure temperature reduces residual stresses while postcure does not. The matrix/interface cracking in dry (0/90)sub 2s Kevlar 49/epoxy laminate is shown to be the result of the residual stress exceeding the transverse strength.

  2. Measuring Agricultural Bias

    DEFF Research Database (Denmark)

    Jensen, Henning Tarp; Robinson, Sherman; Tarp, Finn

    . For the 15 sample countries, the results indicate that the agricultural price incentive bias, which was generally perceived to exist during the 1980s, was largely eliminated during the 1990s. The results also demonstrate that general equilibrium effects and country-specific characteristics - including trade...... shares and intersectoral linkages - are crucial for determining the sign and magnitude of trade policy bias. The GE-ERP measure is therefore uniquely suited to capture the full impact of trade policies on agricultural price incentives. A Monte Carlo procedure confirms that the results are robust...

  3. A study of biases in simulation of the Indian Ocean basin mode and its capacitor effect in CMIP3/CMIP5 models

    Science.gov (United States)

    Tao, Weichen; Huang, Gang; Hu, Kaiming; Gong, Hainan; Wen, Guanhuan; Liu, Lin

    2016-01-01

    Based on 15 Coupled Model Intercomparison Project (CMIP) phase 3 (CMIP3) and 32 CMIP phase 5 (CMIP5) models, a detailed diagnosis was carried out to understand what compose the biases in simulation of the Indian Ocean basin mode (IOBM) and its capacitor effect. Cloud-radiation-SST (CRS) feedback and wind-evaporation-SST (WES) feedback are the two major atmospheric processes for SST changes. Most CMIP models simulate a stronger CRS feedback and a weaker WES feedback. During boreal fall of the El Niño/Southern Oscillation developing year and the following spring, there are weak biases of suppressed rainfall anomalies over the Maritime Continent and anomalous anticyclone over South Indian Ocean. Most CMIP models simulate reasonable short wave radiation (SWR) and weaker latent heat flux (LHF) anomalies. This leads to a weak bias of atmospheric processes. During winter, however, the rainfall anomalies are stronger due to west bias, and the anomalous anticyclone is comparable to observations. As such, most models simulate stronger SWR and reasonable LHF anomalies, leading to a strong bias of atmospheric processes. The thermocline feedback is stronger in most models. Though there is a deep bias of climatology thermocline, most models capture reasonable sea surface height-induced SST anomalies. Therefore, the effect of oceanic processes offset the weak bias of atmospheric processes in spring, and the tropical Indian Ocean warming persists into summer. However, anomalous northwest Pacific (NWP) anticyclone is weaker due to weak and west bias of the capacitor effect. The unrealistic western Pacific SST anomalies in models favor the westward extension of Rossby wave from the Pacific, weakening the effect of Kelvin wave from the Indian Ocean. Moreover, the western Pacific warming forces the NWP anticyclone move farther north than observations, suggesting a major forcing from the Pacific. Compared to CMIP3, CMIP5 models simulate the feedbacks more realistically and display

  4. Effects of differential wavefront sensor bias drifts on high contrast imaging

    CERN Document Server

    Sadakuni, Naru; Palmer, David W; Poyneer, Lisa A; Max, Claire E; Savransky, Dmitry; Thomas, Sandrine J; Cardwell, Andrew; Goodsell, Stephen; Hartung, Markus; Hibon, Pascale; Rantakyrö, Fredrik; Serio, Andrew

    2014-01-01

    The Gemini Planet Imager (GPI) is a new facility, extreme adaptive optics (AO), coronagraphic instrument, currently being integrated onto the 8-meter Gemini South telescope, with the ultimate goal of directly imaging extrasolar planets. To achieve the contrast required for the desired science, it is necessary to quantify and mitigate wavefront error (WFE). A large source of potential static WFE arises from the primary AO wavefront sensor (WFS) detector's use of multiple readout segments with independent signal chains including on-chip preamplifiers and external amplifiers. Temperature changes within GPI's electronics cause drifts in readout segments' bias levels, inducing an RMS WFE of 1.1 nm and 41.9 nm over 4.44 degrees Celsius, for magnitude 4 and 11 stars, respectively. With a goal of $<$2 nm of static WFE, these are significant enough to require remedial action. Simulations imply a requirement to take fresh WFS darks every 2 degrees Celsius of temperature change, for a magnitude 6 star; similarly, for...

  5. Emotional arousal amplifies the effects of biased competition in the brain.

    Science.gov (United States)

    Lee, Tae-Ho; Sakaki, Michiko; Cheng, Ruth; Velasco, Ricardo; Mather, Mara

    2014-12-01

    The arousal-biased competition model predicts that arousal increases the gain on neural competition between stimuli representations. Thus, the model predicts that arousal simultaneously enhances processing of salient stimuli and impairs processing of relatively less-salient stimuli. We tested this model with a simple dot-probe task. On each trial, participants were simultaneously exposed to one face image as a salient cue stimulus and one place image as a non-salient stimulus. A border around the face cue location further increased its bottom-up saliency. Before these visual stimuli were shown, one of two tones played: one that predicted a shock (increasing arousal) or one that did not. An arousal-by-saliency interaction in category-specific brain regions (fusiform face area for salient faces and parahippocampal place area for non-salient places) indicated that brain activation associated with processing the salient stimulus was enhanced under arousal whereas activation associated with processing the non-salient stimulus was suppressed under arousal. This is the first functional magnetic resonance imaging study to demonstrate that arousal can enhance information processing for prioritized stimuli while simultaneously impairing processing of non-prioritized stimuli. Thus, it goes beyond previous research to show that arousal does not uniformly enhance perceptual processing, but instead does so selectively in ways that optimizes attention to highly salient stimuli.

  6. Effect of correlated tRNA abundances on translation errors and evolution of codon usage bias.

    Directory of Open Access Journals (Sweden)

    Premal Shah

    2010-09-01

    Full Text Available Despite the fact that tRNA abundances are thought to play a major role in determining translation error rates, their distribution across the genetic code and the resulting implications have received little attention. In general, studies of codon usage bias (CUB assume that codons with higher tRNA abundance have lower missense error rates. Using a model of protein translation based on tRNA competition and intra-ribosomal kinetics, we show that this assumption can be violated when tRNA abundances are positively correlated across the genetic code. Examining the distribution of tRNA abundances across 73 bacterial genomes from 20 different genera, we find a consistent positive correlation between tRNA abundances across the genetic code. This work challenges one of the fundamental assumptions made in over 30 years of research on CUB that codons with higher tRNA abundances have lower missense error rates and that missense errors are the primary selective force responsible for CUB.

  7. Effect of correlated tRNA abundances on translation errors and evolution of codon usage bias.

    Science.gov (United States)

    Shah, Premal; Gilchrist, Michael A

    2010-09-16

    Despite the fact that tRNA abundances are thought to play a major role in determining translation error rates, their distribution across the genetic code and the resulting implications have received little attention. In general, studies of codon usage bias (CUB) assume that codons with higher tRNA abundance have lower missense error rates. Using a model of protein translation based on tRNA competition and intra-ribosomal kinetics, we show that this assumption can be violated when tRNA abundances are positively correlated across the genetic code. Examining the distribution of tRNA abundances across 73 bacterial genomes from 20 different genera, we find a consistent positive correlation between tRNA abundances across the genetic code. This work challenges one of the fundamental assumptions made in over 30 years of research on CUB that codons with higher tRNA abundances have lower missense error rates and that missense errors are the primary selective force responsible for CUB.

  8. The exchange bias effect in Ni/NiO and NiO nanoparticles

    Science.gov (United States)

    Kou, Angela; Feygenson, Mikhail; Kreno, Lauren; Patete, Jonathan; Tiano, Amanda; Zhang, Fen; Wong, Stanislaus; Aronson, Meigan

    2009-03-01

    We used magnetic measurements, X-ray diffraction, and HRTEM to study the exchange bias field in Ni/NiO and NiO nanoparticles made by a modified wet chemistry method. We oxidized re-dispersed powders of bare Ni nanoparticles in air at 400^oC and 900^oC. HRTEM showed that annealing at 900^oC of bare Ni nanoparticles led to the formation of exceptionally high quality NiO nanoparticles, resembling perfect bulk-like crystalline order. To our knowledge, there are no reports of NiO particles of such quality in the literature. The loop shift was 1000 Oe at 300K for the NiO nanoparticles, while it was only 120 Oe at 10K for the Ni/NiO nanoparticles. The difference is explained by the different origins of the loop shift in Ni/NiO and NiO nanoparticles. In Ni/NiO nanoparticles, the loop shift is associated with exchange interactions between ferromagnetic Ni and antiferromagnetic NiO. In NiO nanoparticles, however, the origin of the shift is an uneven number of ferromagnetic sublattices present in NiO nanoparticles, which interact differently with an applied magnetic field (Kodama, 1999).

  9. Resistance to early-life stress in mice: effects of genetic background and stress duration

    Directory of Open Access Journals (Sweden)

    Helene M. Savignac

    2011-04-01

    Full Text Available Early-life stress can induce marked behavioural and physiological impairments in adulthood including cognitive deficits, depression, anxiety and gastrointestinal dysfunction. Although robust rat models of early-life stress exist there are few established effective paradigms in the mouse. Genetic background and protocol parameters used are two critical variables in such model development.Thus we investigated the impact of two different early-life stress protocols in two commonly used inbred mouse strains. C57BL/6 and innately anxious BALB/c male mice were maternally deprived 3 hrs daily, either from postnatal day 1 to 14 (Protocol 1 or 6 to 10 (Protocol 2. Animals were assessed in adulthood for cognitive performance (spontaneous alternation behaviour test, anxiety (open field, light/dark box and elevated plus maze tests and depression-related behaviours (forced swim test in addition to stress-sensitive physiological changes. Overall, the results showed that early-life stressed mice from both strains displayed good cognitive ability and no elevations in anxiety. However, paradoxical changes occurred in C57BL/6 mice as the longer protocol (protocol 1 decreased anxiety in the light-dark box and increased exploration in the elevated plus maze. In BALB/c mice there were also limited effects of maternal separation with both separation protocols inducing reductions in stress-induced defecation and protocol 1 reducing the colon length. These data suggest that, independent of stress duration, mice from both strains were on the whole resilient to the maladaptive effects of early-life stress. Thus maternal-separation models of brain-gut axis dysfunction should rely on either different stressor protocols or other strains of mice.

  10. Stretching the stress boundary: Linking air pollution health effects to a neurohormonal stress response.

    Science.gov (United States)

    Kodavanti, Urmila P

    2016-12-01

    Inhaled pollutants produce effects in virtually all organ systems in our body and have been linked to chronic diseases including hypertension, atherosclerosis, Alzheimer's and diabetes. A neurohormonal stress response (referred to here as a systemic response produced by activation of the sympathetic nervous system and hypothalamus-pituitary-adrenal (HPA)-axis) has been implicated in a variety of psychological and physical stresses, which involves immune and metabolic homeostatic mechanisms affecting all organs in the body. In this review, we provide new evidence for the involvement of this well-characterized neurohormonal stress response in mediating systemic and pulmonary effects of a prototypic air pollutant - ozone. A plethora of systemic metabolic and immune effects are induced in animals exposed to inhaled pollutants, which could result from increased circulating stress hormones. The release of adrenal-derived stress hormones in response to ozone exposure not only mediates systemic immune and metabolic responses, but by doing so, also modulates pulmonary injury and inflammation. With recurring pollutant exposures, these effects can contribute to multi-organ chronic conditions associated with air pollution. This review will cover, 1) the potential mechanisms by which air pollutants can initiate the relay of signals from respiratory tract to brain through trigeminal and vagus nerves, and activate stress responsive regions including hypothalamus; and 2) the contribution of sympathetic and HPA-axis activation in mediating systemic homeostatic metabolic and immune effects of ozone in various organs. The potential contribution of chronic environmental stress in cardiovascular, neurological, reproductive and metabolic diseases, and the knowledge gaps are also discussed. This article is part of a Special Issue entitled Air Pollution, edited by Wenjun Ding, Andrew J. Ghio and Weidong Wu.

  11. Theoretical investigation of exchange bias

    Institute of Scientific and Technical Information of China (English)

    Xiong Zhi-Jie; Wang Huai-Yu; Ding Ze-Jun

    2007-01-01

    The exchange bias of bilayer magnetic films consisting of ferromagnetic (FM) and antiferromagnetic (AFM) layers in an uncompensated case is studied by use of the many-body Green's function method of quantum statistical theory.The effects of the layer thickness and temperature and the interfacial coupling strength on the exchange bias HE are investigated. The dependence of the exchange bias HE on the FM layer thickness and temperature is qualitatively in agreement with experimental results. When temperature varies, both the coercivity HC and HE decrease with the temperature increasing. For each FM thickness, there exists a least AFM thickness in which the exchange bias occurs,which is called pinning thickness.

  12. Effects of Cadmium Stress on the Quality of Rice Seeds

    Institute of Scientific and Technical Information of China (English)

    Juan; CHEN; Hui; FANG; Ying; ZHANG; Yuanyuan; FAN

    2013-01-01

    Germination and hydroponic experiments are performed on rice seeds growing in soils treated with Cd stress,with rice seeds of the same variety that is not treated with Cd stress as a control,to study the effects of Cd stress on quality of rice seeds.The results have shown that:(1)Cd stress reduces the thousand grain weight of rice seeds,and higher Cd content means lower thousand grain weight;(2)The germination vigor and germination percentage of rice seeds under Cd stress as well as theirα-amylase activity andβ-amylase activity are all lower than those of the control.They decreases as the Cd stress increases;(3)For rice seeds under Cd stress,the height,fresh and dry weight of seedlings,as well as the chlorophyll content,photosynthetic rate and content of soluble protein of their leaves are all lower than those of the control.This indicates that Cd stress has certain effects on the germination and growth of the rice seeds.

  13. Effects of heat stress on baroreflex function in humans

    Science.gov (United States)

    Crandall, Craig G.; Cui, Jian; Wilson, Thad E.

    2003-01-01

    INTRODUCTION: Heat stress significantly reduces orthostatic tolerance in humans. The mechanism(s) causing this response remain unknown. The purpose of this review article is to present data pertaining to the hypothesis that reduced orthostatic tolerance in heat stressed individuals is a result of heat stress induced alterations in baroflex function. METHODS: In both normothermic and heat stressed conditions baroreflex responsiveness was assessed via pharmacological and non-pharmacological methods. In addition, the effects of heat stress on post-synaptic vasoconstrictor responsiveness were assessed. RESULTS: Generally, whole body heating did not alter baroreflex sensitivity defined as the gain of the linear portion of the baroreflex curve around the operating point. However, whole body heating shifted the baroreflex curve to the prevailing (i.e. elevated) heart rate and muscle sympathetic nerve activity. Finally, the heat stress impaired vasoconstrictor responses to exogenous administration of adrenergic agonists. CONCLUSION: Current data do not support the hypothesis that reduced orthostatic tolerance associated with heat stress in humans is due to impaired baroreflex responsiveness. This phenomenon may be partially due to the effects of heat stress on reducing vasoconstrictor responsiveness.

  14. Cohesive stresses and size effect in quasi-brittle materials

    Indian Academy of Sciences (India)

    V E Saouma; D Natekar

    2002-08-01

    A novel approach to the derivation of Ba$\\breve{z}$ant’s size effect law is presented. Contrarily to the original Lagrangian derivation which hinged on energetic consideration, a Newtonian approach based on local stress intensity factors is presented. Through this approach, it is shown that Ba$\\breve{z}$ant’s size effect law is the first (and dominant) term in a series expansion for the nominal stress. Furthermore, analytical expressions for are derived for selected specimen geometries.

  15. A probability model for evaluating the bias and precision of influenza vaccine effectiveness estimates from case-control studies.

    Science.gov (United States)

    Haber, M; An, Q; Foppa, I M; Shay, D K; Ferdinands, J M; Orenstein, W A

    2015-05-01

    As influenza vaccination is now widely recommended, randomized clinical trials are no longer ethical in many populations. Therefore, observational studies on patients seeking medical care for acute respiratory illnesses (ARIs) are a popular option for estimating influenza vaccine effectiveness (VE). We developed a probability model for evaluating and comparing bias and precision of estimates of VE against symptomatic influenza from two commonly used case-control study designs: the test-negative design and the traditional case-control design. We show that when vaccination does not affect the probability of developing non-influenza ARI then VE estimates from test-negative design studies are unbiased even if vaccinees and non-vaccinees have different probabilities of seeking medical care against ARI, as long as the ratio of these probabilities is the same for illnesses resulting from influenza and non-influenza infections. Our numerical results suggest that in general, estimates from the test-negative design have smaller bias compared to estimates from the traditional case-control design as long as the probability of non-influenza ARI is similar among vaccinated and unvaccinated individuals. We did not find consistent differences between the standard errors of the estimates from the two study designs.

  16. Differential effect of aneuploidy on the X chromosome and genes with sex-biased expression in Drosophila.

    Science.gov (United States)

    Sun, Lin; Johnson, Adam F; Li, Jilong; Lambdin, Aaron S; Cheng, Jianlin; Birchler, James A

    2013-10-01

    Global analysis of gene expression via RNA sequencing was conducted for trisomics for the left arm of chromosome 2 (2L) and compared with the normal genotype. The predominant response of genes on 2L was dosage compensation in that similar expression occurred in the trisomic compared with the diploid control. However, the male and female trisomic/normal expression ratio distributions for 2L genes differed in that females also showed a strong peak of genes with increased expression and males showed a peak of reduced expression relative to the opposite sex. For genes in other autosomal regions, the predominant response to trisomy was reduced expression to the inverse of the altered chromosomal dosage (2/3), but a minor peak of increased expression in females and further reduced expression in males were also found, illustrating a sexual dimorphism for the response to aneuploidy. Moreover, genes with sex-biased expression as revealed by comparing amounts in normal males and females showed responses of greater magnitude to trisomy 2L, suggesting that the genes involved in dosage-sensitive aneuploid effects also influence sex-biased expression. Each autosomal chromosome arm responded to 2L trisomy similarly, but the ratio distributions for X-linked genes were distinct in both sexes, illustrating an X chromosome-specific response to aneuploidy.

  17. Generation of pure spin currents via spin Seebeck effect in self-biased hexagonal ferrite thin films

    Energy Technology Data Exchange (ETDEWEB)

    Li, Peng; Ellsworth, David; Chang, Houchen; Janantha, Praveen; Richardson, Daniel; Phillips, Preston; Vijayasarathy, Tarah; Wu, Mingzhong, E-mail: mwu@lamar.colostate.edu [Department of Physics, Colorado State University, Fort Collins, Colorado 80523 (United States); Shah, Faisal [Department of Electrical Engineering, University of Notre Dame, Notre Dame, Indiana 46556 (United States)

    2014-12-15

    Light-induced generation of pure spin currents in a Pt(2.5 nm)/BaFe{sub 12}O{sub 19}(1.2 μm)/sapphire(0.5 mm) structure is reported. The BaFe{sub 12}O{sub 19} film had strong in-plane uniaxial anisotropy and was therefore self-biased. Upon exposure to light, a temperature difference (ΔT) was established across the BaFe{sub 12}O{sub 19} thickness that gave rise to a pure spin current in the Pt via the spin Seebeck effect. Via the inverse spin Hall effect, the spin current produced an electric voltage across one of the Pt lateral dimensions. The voltage varied with time in the same manner as ΔT and flipped its sign when the magnetization in BaFe{sub 12}O{sub 19} was reversed.

  18. Effect of hydrogen on stress corrosion cracking of copper

    Institute of Scientific and Technical Information of China (English)

    Li-jie QIAO

    2008-01-01

    The effects of hydrogen on electrochemical behavior and susceptibility of stress corrosion cracking (SCC) of pure copper were studied. SCC susceptibility of pure copper in a 1 M NaNO2 solution was increased by pre-charged hydrogen. The effect of hydrogen on the sus-ceptibility is more obvious in the low stress region due to the longer fracture time, which resulted in a longer time for more hydrogen to diffuse toward the crack tip. Synergistic effects of hydrogen and stress on corrosion and SCC pro-cesses were discussed. The results showed that an inter-action between stress and hydrogen at the crack tip could increase the anodic dissolution rate remarkably.

  19. Effect of yoga on academic performance in relation to stress

    Directory of Open Access Journals (Sweden)

    Kauts Amit

    2009-01-01

    Full Text Available Background: Academic performance is concerned with the quantity and quality of learning attained in a subject or group of subjects after a long period of instruction. Excessive stress hampers students′ performance. Improvement in academic performance and alertness has been reported in several yogic studies. Aims and Objectives: The main objective of the study was to assess the effect of yoga on academic performance in relation to stress. Materials and Methods: The study started with 800 adolescent students; 159 high-stress students and 142 low-stress students were selected on the basis of scores obtained through Stress Battery. Experimental group and control group were given pre test in three subjects, i.e., Mathematics, Science, and Social Studies. A yoga module consisting of yoga asanas, pranayama, meditation, and a value orientation program was administered on experimental group for 7 weeks. The experimental and control groups were post-tested for their performance on the three subjects mentioned above. Results: The results show that the students, who practiced yoga performed better in academics. The study further shows that low-stress students performed better than high-stress students, meaning thereby that stress affects the students′ performance.

  20. The effects of yoga on anxiety and stress.

    Science.gov (United States)

    Li, Amber W; Goldsmith, Carroll-Ann W

    2012-03-01

    Stress and anxiety have been implicated as contributors to many chronic diseases and to decreased quality of life, even with pharmacologic treatment. Efforts are underway to find non-pharmacologic therapies to relieve stress and anxiety, and yoga is one option for which results are promising. The focus of this review is on the results of human trials assessing the role of yoga in improving the signs and symptoms of stress and anxiety. Of 35 trials addressing the effects of yoga on anxiety and stress, 25 noted a significant decrease in stress and/or anxiety symptoms when a yoga regimen was implemented; however, many of the studies were also hindered by limitations, such as small study populations, lack of randomization, and lack of a control group. Fourteen of the 35 studies reported biochemical and physiological markers of stress and anxiety, but yielded inconsistent support of yoga for relief of stress and anxiety. Evaluation of the current primary literature is suggestive of benefits of yoga in relieving stress and anxiety, but further investigation into this relationship using large, well-defined populations, adequate controls, randomization and long duration should be explored before recommending yoga as a treatment option.

  1. Emotionally biased cognitive processes: the weakest link predicts prospective changes in depressive symptom severity.

    Science.gov (United States)

    Everaert, Jonas; Duyck, Wouter; Koster, Ernst H W

    2015-01-01

    Emotional biases in attention, interpretation, and memory are predictive of future depressive symptoms. It remains unknown, however, how these biased cognitive processes interact to predict depressive symptom levels in the long-term. In the present study, we tested the predictive value of two integrative approaches to model relations between multiple biased cognitive processes, namely the additive (i.e., cognitive processes have a cumulative effect) vs. the weakest link (i.e., the dominant pathogenic process is important) model. We also tested whether these integrative models interacted with perceived stress to predict prospective changes in depressive symptom severity. At Time 1, participants completed measures of depressive symptom severity and emotional biases in attention, interpretation, and memory. At Time 2, one year later, participants were reassessed to determine depressive symptom levels and perceived stress. Results revealed that the weakest link model had incremental validity over the additive model in predicting prospective changes in depressive symptoms, though both models explained a significant proportion of variance in the change in depressive symptoms from Time 1 to Time 2. None of the integrative models interacted with perceived stress to predict changes in depressive symptomatology. These findings suggest that the best cognitive marker of the evolution in depressive symptoms is the cognitive process that is dominantly biased toward negative material, which operates independent from experienced stress. This highlights the importance of considering idiographic cognitive profiles with multiple cognitive processes for understanding and modifying effects of cognitive biases in depression.

  2. The effect of music on the human stress response.

    Directory of Open Access Journals (Sweden)

    Myriam V Thoma

    Full Text Available BACKGROUND: Music listening has been suggested to beneficially impact health via stress-reducing effects. However, the existing literature presents itself with a limited number of investigations and with discrepancies in reported findings that may result from methodological shortcomings (e.g. small sample size, no valid stressor. It was the aim of the current study to address this gap in knowledge and overcome previous shortcomings by thoroughly examining music effects across endocrine, autonomic, cognitive, and emotional domains of the human stress response. METHODS: Sixty healthy female volunteers (mean age = 25 years were exposed to a standardized psychosocial stress test after having been randomly assigned to one of three different conditions prior to the stress test: 1 relaxing music ('Miserere', Allegri (RM, 2 sound of rippling water (SW, and 3 rest without acoustic stimulation (R. Salivary cortisol and salivary alpha-amylase (sAA, heart rate (HR, respiratory sinus arrhythmia (RSA, subjective stress perception and anxiety were repeatedly assessed in all subjects. We hypothesized that listening to RM prior to the stress test, compared to SW or R would result in a decreased stress response across all measured parameters. RESULTS: The three conditions significantly differed regarding cortisol response (p = 0.025 to the stressor, with highest concentrations in the RM and lowest in the SW condition. After the stressor, sAA (p=0.026 baseline values were reached considerably faster in the RM group than in the R group. HR and psychological measures did not significantly differ between groups. CONCLUSION: Our findings indicate that music listening impacted the psychobiological stress system. Listening to music prior to a standardized stressor predominantly affected the autonomic nervous system (in terms of a faster recovery, and to a lesser degree the endocrine and psychological stress response. These findings may help better understanding the

  3. Effect of ground stress on hydraulic fracturing of methane well

    Institute of Scientific and Technical Information of China (English)

    DU Chun-zhi; MAO Xian-biao; MIAO Xie-xing; WANG Peng

    2008-01-01

    Most of the coal reservoirs in China are of low-permeability, so hydraulic fracturing is widely used to improve the permeability in the extraction of gas by ground drilling. The ground stress around the well was analyzed by using theory of elasticity. The pressure when the well fractured is formulated and the effect of ground stress on pressure is discussed. The effect of ground-stress-differences on hydraulic fracturing was analyzed by using the numerical software RFPA2D-Flow in reference to the tectonic stress in Jincheng coal area. The results show that: 1) the position where initial fracture appears is random and fracture branches emerge when the fractures expand if ground stresses in any two directions within a horizontal plane are equal; 2) otherwise, the fractures expand in general along the direction of maximum ground stress and the critical pressure decreases with increasing ground-stress-differences and 3) the preferred well-disposition pattern is diamond shaped. The preferred well spacing is 250 m×300 m. This study can provide a reference for the design of wells.

  4. Per capita interactions and stress tolerance drive stress-induced changes in biodiversity effects on ecosystem functions.

    Science.gov (United States)

    Baert, Jan M; Janssen, Colin R; Sabbe, Koen; De Laender, Frederik

    2016-08-18

    Environmental stress changes the relationship between biodiversity and ecosystem functions, but the underlying mechanisms are poorly understood. Because species interactions shape biodiversity-ecosystem functioning relationships, changes in per capita interactions under stress (as predicted by the stress gradient hypothesis) can be an important driver of stress-induced changes in these relationships. To test this hypothesis, we measure productivity in microalgae communities along a diversity and herbicide gradient. On the basis of additive partitioning and a mechanistic community model, we demonstrate that changes in per capita interactions do not explain effects of herbicide stress on the biodiversity-productivity relationship. Instead, assuming that the per capita interactions remain unaffected by stress, causing species densities to only change through differences in stress tolerance, suffices to predict the stress-induced changes in the biodiversity-productivity relationship and community composition. We discuss how our findings set the stage for developing theory on how environmental stress changes biodiversity effects on ecosystem functions.

  5. Anisotropic behavior of exchange bias effect in tensile-deformed Pt{sub 3}Fe single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Satoru, E-mail: koba@iwate-u.ac.jp; Morita, Ryo [Department of Materials Science and Engineering, Faculty of Engineering, Iwate University, Ueda 4-3-5, Morioka 020-8551 (Japan)

    2015-05-07

    Plastic strain in Pt{sub 3}Fe causes changes in the atomic arrangement around the (111) glide plane and induces ferromagnetism even at room temperature. We have performed detailed magnetization measurements on a Pt{sub 3}Fe single crystal with plastic strains of 11.6% under magnetic fields in various directions with respect to the [100] strain axis in order to elucidate the reversal mechanism of induced ferromagnetic domains. We observed that by decreasing the angle between the magnetization direction and strain axis, hysteresis loops are strongly sheared, which is associated with a large increase in coercivity. We also observed that an exchange bias effect appears for all field orientations, but the exchange field maximizes for an intermediate field direction. On the other hand, both phenomena are insensitive to magnetic fields perpendicular to the [100] strain axis. These observations were explained by a single-domain model with uniaxial anisotropy along the [100] strain axis.

  6. Testing the BIAS map model: the positive effects of perceiving weakness and harmony in powerful out-groups.

    Science.gov (United States)

    Echebarria-Echabe, Agustin

    2013-01-01

    Two experimental studies were used to test predictions derived from the BIAS map model. While the first experiment manipulated the perception of power in the out-group (the USA), the second manipulated the perceived harmony of the relationships between this out-group and the participants' own national group. The results confirmed the hypotheses derived from the model. The manipulation of power affected the perception of competence, thus affecting emotions and behavioral dispositions towards out-group members. The manipulation of perceived harmony of intergroup interests had a similar effect, but was not mediated by changes in the attribution of competence, but of warmth. Attitudes did not play a significant role in the prediction of emotions and behavioral intentions.

  7. The role of somatic threat feature detectors in the attentional bias toward pain: effects of spatial attention.

    Science.gov (United States)

    Dowman, Robert

    2011-03-01

    Our previous work suggests that somatic threat feature detectors indexed by a pain-evoked midlatency negative scalp potential play an important role in the attentional bias toward pain. In these studies the somatic threat feature detectors facilitated the shift in attention to a somatic threat when attention was focused on another stimulus modality but not when it was focused on another spatial location. This experiment used the Posner cuing paradigm to investigate possible explanations for this discrepancy. The results demonstrate that the different somatic threat effects observed in previous modal and spatial cuing studies are not due to attentional set. Rather, this discrepancy may be related to differences in contingent attention capture. This study also verifies earlier findings suggesting that some of the pain-related P2 component generators are involved in stimulus-driven shifts in spatial attention toward task-relevant stimuli.

  8. Tunable exchange bias-like effect in patterned hard-soft two-dimensional lateral composites with perpendicular magnetic anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Hierro-Rodriguez, A., E-mail: ahierro@fc.up.pt; Alvarez-Prado, L. M.; Martín, J. I.; Alameda, J. M. [Departamento de Física, Universidad de Oviedo, C/Calvo Sotelo S/N, 33007 Oviedo (Spain); Centro de Investigación en Nanomateriales y Nanotecnología—CINN (CSIC—Universidad de Oviedo—Principado de Asturias), Parque Tecnológico de Asturias, 33428 Llanera (Spain); Teixeira, J. M. [IN-IFIMUP, Departamento de Física e Astronomia, Faculdade de Ciências, Universidade do Porto, Rua Campo Alegre 687, 4169-007 Porto (Portugal); Vélez, M. [Departamento de Física, Universidad de Oviedo, C/Calvo Sotelo S/N, 33007 Oviedo (Spain)

    2014-09-08

    Patterned hard-soft 2D magnetic lateral composites have been fabricated by e-beam lithography plus dry etching techniques on sputter-deposited NdCo{sub 5} thin films with perpendicular magnetic anisotropy. Their magnetic behavior is strongly thickness dependent due to the interplay between out-of-plane anisotropy and magnetostatic energy. Thus, the spatial modulation of thicknesses leads to an exchange coupled system with hard/soft magnetic regions in which rotatable anisotropy of the thicker elements provides an extra tool to design the global magnetic behavior of the patterned lateral composite. Kerr microscopy studies (domain imaging and magneto-optical Kerr effect magnetometry) reveal that the resulting hysteresis loops exhibit a tunable exchange bias-like shift that can be switched on/off by the applied magnetic field.

  9. Effect of Stress on Transformer Insulation

    Directory of Open Access Journals (Sweden)

    Kapil Gandhi

    2012-06-01

    Full Text Available Power transformers use Kraft paper as insulation in the electrical windings present in the core, which is immersed in oil. In service, the temperature of the windings of core will go to 750C to 850C. If the transformer is over loaded, then the temperature can exceed upto 100°C causing the cellulose chains in the paper to cleave at an accelerated rate, which results in the degradation of mechanical strength and performance of the insulation. The Degree of Polymerization (DP will also decrease. If proper action will not take, this can lead to failure of the transformer and disruption to electricity supply and large economic losses to the operating utility. Transformer condition should be maintained because of its importance to electricity network. The life of transformer depends on the life of the oil impregnated paper insulation system to greater extent. Degradation of the cellulose insulation is an irreversible process. After thermal degradation of the paper winding, Furfuraldehyde (FFA is the chemical compound, which is released into the oil from paper. The concentration of FFA has been directly related to the condition of the paper insulation. In the present paper an experimental investigation has been made to evaluate the degradation of transformer oil contaminated by nano-particles of pine wood under accelerated thermal and electrical stress and results are correlated with breakdown strength, density & interfacial tension of the pure oil. The contaminated oil samples are tested at electric stress of 2.0 kV, 3.0 kV, 4.0 kV & 5.0 kV for 24, 48, 72 & 96 hours simultaneously.

  10. Effects of Substrate Bias on the Hardness and Resistivity of Reactively Sputtered TaN and TiN Thin Films

    Science.gov (United States)

    Lu, Junqing; Arshi, Nishat

    2016-06-01

    TaN and TiN films are being widely used as conductive layers in electronic devices or protective coatings on metal surfaces. Among various deposition methods, reactive magnetron sputtering is preferred partly due to its ability to control the energy of the depositing ions by applying different substrate bias voltages. In this study, TaN and TiN films were deposited on Si/SiO2 substrates by using direct current magnetron sputtering technique with 370 W target power at 1.9 mTorr and under different substrate biases. The effects of the substrate bias on both the resistivity and the hardness of the deposited TaN and TiN films were investigated. The phase and composition of the deposited films were investigated by x-ray diffraction, the resistivity was measured by a four-point probe, and the hardness was obtained by nano-indentation. For TaN films, the use of substrate bias not only increased the hardness but also increased the resistivity. Moreover, the formation of the Ta3N5 phase at the -300 V substrate bias significantly increased the TaN film resistivity. For TiN films, the optimum resistivity (minimum) of 19.5 µΩ-cm and the hardness (maximum) of 31.5 GPa were achieved at the -100 V substrate bias. Since the phase changes occurred in both the TaN and the TiN films at higher substrate biases and these phase changes negatively affected the resistivity or hardness property of the films, the substrate bias should not significantly exceed -100 V.

  11. Imagining a brighter future: The effect of positive imagery training on mood, prospective mental imagery and emotional bias in older adults

    Science.gov (United States)

    Murphy, Susannah E.; Clare O’Donoghue, M.; Drazich, Erin H.S.; Blackwell, Simon E.; Christina Nobre, Anna; Holmes, Emily A.

    2015-01-01

    Positive affect and optimism play an important role in healthy ageing and are associated with improved physical and cognitive health outcomes. This study investigated whether it is possible to boost positive affect and associated positive biases in this age group using cognitive training. The effect of computerised imagery-based cognitive bias modification on positive affect, vividness of positive prospective imagery and interpretation biases in older adults was measured. 77 older adults received 4 weeks (12 sessions) of imagery cognitive bias modification or a control condition. They were assessed at baseline, post-training and at a one-month follow-up. Both groups reported decreased negative affect and trait anxiety, and increased optimism across the three assessments. Imagery cognitive bias modification significantly increased the vividness of positive prospective imagery post-training, compared with the control training. Contrary to our hypothesis, there was no difference between the training groups in negative interpretation bias. This is a useful demonstration that it is possible to successfully engage older adults in computer-based cognitive training and to enhance the vividness of positive imagery about the future in this group. Future studies are needed to assess the longer-term consequences of such training and the impact on affect and wellbeing in more vulnerable groups. PMID:26235478

  12. Imagining a brighter future: the effect of positive imagery training on mood, prospective mental imagery and emotional bias in older adults.

    Science.gov (United States)

    Murphy, Susannah E; Clare O'Donoghue, M; Drazich, Erin H S; Blackwell, Simon E; Christina Nobre, Anna; Holmes, Emily A

    2015-11-30

    Positive affect and optimism play an important role in healthy ageing and are associated with improved physical and cognitive health outcomes. This study investigated whether it is possible to boost positive affect and associated positive biases in this age group using cognitive training. The effect of computerised imagery-based cognitive bias modification on positive affect, vividness of positive prospective imagery and interpretation biases in older adults was measured. 77 older adults received 4 weeks (12 sessions) of imagery cognitive bias modification or a control condition. They were assessed at baseline, post-training and at a one-month follow-up. Both groups reported decreased negative affect and trait anxiety, and increased optimism across the three assessments. Imagery cognitive bias modification significantly increased the vividness of positive prospective imagery post-training, compared with the control training. Contrary to our hypothesis, there was no difference between the training groups in negative interpretation bias. This is a useful demonstration that it is possible to successfully engage older adults in computer-based cognitive training and to enhance the vividness of positive imagery about the future in this group. Future studies are needed to assess the longer-term consequences of such training and the impact on affect and wellbeing in more vulnerable groups.

  13. Effects of external stress on defect complexes in semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Tessema, Genene [Department of Physics, Addis Ababa University, PO Box 1176, Addis Ababa (Ethiopia); Helmholtz-Institut fuer Strahlen und Kernphysik, Nussalle 14-16, 53115 Bonn (Germany)

    2007-07-04

    Crystal field gradients that exist at lattice sites in solids depend on the symmetry of charge distribution around atomic sites. The charge symmetry could be broken either by the presence of impurity complexes in the host matrix or by external stress on the samples, which leads to an observable magnitude of electric field gradients (EFGs). The perturbed {gamma}-{gamma} angular correlation (PAC) method is employed here to investigate the effect of uniaxial stress on {sup 111}Cd sites in crystalline doped semiconductors.

  14. Effect of yoga on academic performance in relation to stress

    OpenAIRE

    Kauts Amit; Sharma Neelam

    2009-01-01

    Background: Academic performance is concerned with the quantity and quality of learning attained in a subject or group of subjects after a long period of instruction. Excessive stress hampers students′ performance. Improvement in academic performance and alertness has been reported in several yogic studies. Aims and Objectives: The main objective of the study was to assess the effect of yoga on academic performance in relation to stress. Materials and Methods: The study started ...

  15. Mechanical behavior and stress effects in hard superconductors: a review

    Energy Technology Data Exchange (ETDEWEB)

    Koch, C. C.; Easton, D. S.

    1977-11-01

    The mechanical properties of type II superconducting materials are reviewed as well as the effect of stress on the superconducting properties of these materials. The bcc alloys niobium-titanium and niobium-zirconium exhibit good strength and extensive ductility at room temperature. Mechanical tests on these alloys at 4.2/sup 0/K revealed serrated stress-strain curves, nonlinear elastic effects and reduced ductility. The nonlinear behavior is probably due to twinning and detwinning or a reversible stress-induced martensitic transformation. The brittle A-15 compound superconductors, such as Nb/sub 3/Sn and V/sub 3/Ga, exhibit unusual elastic properties and structural instabilities at cryogenic temperatures. Multifilamentary composites consisting of superconducting filaments in a normal metal matrix are generally used for superconducting devices. The mechanical properties of alloy and compound composites, tapes, as well as composites of niobium carbonitride chemically vapor deposited on high strength carbon fibers are presented. Hysteretic stress-strain behavior in the metal matrix composites produces significant heat generation, an effect which may lead to degradation in the performance of high field magnets. Measurements of the critical current density, J/sub c/, under stress in a magnetic field are reported. Modest stress-reversible degradation in J/sub c/ was observed in niobium-titanium composites, while more serious degradation was found in Nb/sub 3/Sn samples. The importance of mechanical behavior to device performance is discussed.

  16. Stress effects on memory: an update and integration.

    Science.gov (United States)

    Schwabe, Lars; Joëls, Marian; Roozendaal, Benno; Wolf, Oliver T; Oitzl, Melly S

    2012-08-01

    It is well known that stressful experiences may affect learning and memory processes. Less clear is the exact nature of these stress effects on memory: both enhancing and impairing effects have been reported. These opposite effects may be explained if the different time courses of stress hormone, in particular catecholamine and glucocorticoid, actions are taken into account. Integrating two popular models, we argue here that rapid catecholamine and non-genomic glucocorticoid actions interact in the basolateral amygdala to shift the organism into a 'memory formation mode' that facilitates the consolidation of stressful experiences into long-term memory. The undisturbed consolidation of these experiences is then promoted by genomic glucocorticoid actions that induce a 'memory storage mode', which suppresses competing cognitive processes and thus reduces interference by unrelated material. Highlighting some current trends in the field, we further argue that stress affects learning and memory processes beyond the basolateral amygdala and hippocampus and that stress may pre-program subsequent memory performance when it is experienced during critical periods of brain development.

  17. Innovative Opioid Peptides and Biased Agonism: Novel Avenues for More Effective and Safer Analgesics to Treat Chronic Pain.

    Science.gov (United States)

    Bedini, Andrea; Spampinato, Santi Mario

    2017-02-15

    Chronic pain is a clinically relevant and yet unsolved conditions that is poorly treated with the currently available drugs, thus highlighting the urgent need of innovative analgesics. Although opiates are not very effective in the treatment of inflammatory and neuropathic pain, developing novel opioid receptor peptide agonists, as well as modulating the opioid receptor-mediated responses in a ligand-specific fashion, may represent an innovative and promising strategy to identify more efficacious and safer antalgic drugs. In this review, novel analogues of endomorphin 1 (a mu opioid receptor selective agonist able to induce analgesia in different animal models of pain - including neuropathic pain) and dermorphin (one of the most potent opioid peptide existing in nature) will be discussed as they are emerging as a promising starting point to develop novel opioid agonists: endomorphin 1 analogues, in fact, may determine antinociception in different models of neuropathic pain with reduced side effects as compared to classic opiates as morphine; dermorphin analogues may elicit analgesia in animal models of both inflammatory and neuropathic pain and with less severe adverse effects. Furthermore, such opioid peptides may allow to explore unprecedented modalities of ligand-receptor interactions, helping to characterize biased agonism at opioid receptors: exploiting functional selectivity at opioid receptor may lead to identify innovative analgesic with improved pharmacological responses and optimized side effects. Thus, innovative opioid peptides, as those outlined in this review, are promising candidates to develop more effective opioid analgesics to be employed as medications for chronic pain states, as inflammatory or neuropathic pain.

  18. An integrative lens model approach to bias and accuracy in human inferences: hindsight effects and knowledge updating in personality judgments.

    Science.gov (United States)

    Nestler, Steffen; Egloff, Boris; Küfner, Albrecht C P; Back, Mitja D

    2012-10-01

    The present article integrates research on the accurate inference of personality traits with process models of hindsight bias (the tendency to exaggerate in hindsight what one had said in foresight). Specifically, the article suggests a new model that integrates assumptions of the lens model on accurate personality judgments and accounts that view hindsight effects as a by-product of knowledge updating. We suggest 3 processes that have the potential to explain the occurrence of hindsight effects in personality judgments: (a) changes in an individual's cue perceptions, (b) changes in the utilization of more valid cues, and (c) changes in the consistency with which cue knowledge is applied. In 2 studies (N1 = 91, N2 = 93), participants were presented with target pictures and were asked to judge each target's levels of the Big Five. Thereafter, they received feedback and had to recall their original judgments. Results show that there were clear hindsight effects for all 5 personality dimensions. Importantly, we found evidence that both the utilization of more valid cues and changes in cue perceptions--but not changes in the consistency with which cue knowledge is applied--account for the hindsight effects. Implications of these results for models explaining hindsight effects, the inference of personality judgments, and the accuracy of these inferences are discussed.

  19. Opposite Effects of Early-Life Competition and Developmental Telomere Attrition on Cognitive Biases in Juvenile European Starlings.

    Directory of Open Access Journals (Sweden)

    Melissa Bateson

    Full Text Available Moods are enduring affective states that we hypothesise should be affected by an individual's developmental experience and its current somatic state. We tested whether early-life adversity, induced by manipulating brood size, subsequently altered juvenile European starlings' (Sturnus vulgaris decisions in a judgment bias task designed to provide a cognitive measure of mood. We predicted that starlings from larger broods, specifically those that had experienced more nest competitors larger than themselves would exhibit reduced expectation of reward, indicative of a 'pessimistic', depression-like mood. We used a go/no-go task, in which 30 starlings were trained to probe a grey card disc associated with a palatable mealworm hidden underneath and avoid a different shade of grey card disc associated with a noxious quinine-injected mealworm hidden underneath. Birds' response latencies to the trained stimuli and also to novel, ambiguous stimuli intermediate between these were subsequently tested. Birds that had experienced greater competition in the nest were faster to probe trained stimuli, and it was therefore necessary to control statistically for this difference in subsequent analyses of the birds' responses to the ambiguous stimuli. As predicted, birds with more, larger nest competitors showed relatively longer latencies to probe ambiguous stimuli, suggesting reduced expectation of reward and a 'pessimistic', depression-like mood. However, birds with greater developmental telomere attrition--a measure of cellular aging associated with increased morbidity and reduced life-expectancy that we argue could be used as a measure of somatic state--showed shorter latencies to probe ambiguous stimuli. This would usually be interpreted as evidence for a more positive or 'optimistic' affective state. Thus, increased competition in the nest and poor current somatic state appear to have opposite effects on cognitive biases. Our results lead us to question

  20. Effect of reporting bias on meta-analyses of drug trials

    DEFF Research Database (Denmark)

    Hart, Beth; Lundh, Andreas; Bero, Lisa

    2012-01-01

    To investigate the effect of including unpublished trial outcome data obtained from the Food and Drug Administration (FDA) on the results of meta-analyses of drug trials.......To investigate the effect of including unpublished trial outcome data obtained from the Food and Drug Administration (FDA) on the results of meta-analyses of drug trials....

  1. Effects of chronic stress on sleep in rats.

    Science.gov (United States)

    Kant, G J; Pastel, R H; Bauman, R A; Meininger, G R; Maughan, K R; Robinson, T N; Wright, W L; Covington, P S

    1995-02-01

    The present study was conducted to determine the effects of chronic stress on sleep using a rodent paradigm of around-the-clock signalled intermittent foot shock in which some rats can pull a chain to avoid/escape shock while another group of rats is yoked to the first group. We measured sleep using telemetry; four-channel EEG was collected 24 h/day in rats during 2 prestress days; days 1, 2, 3, 7, and 14 during chronic stress; and 3 poststress days. States of REM sleep, non-REM (NREM) sleep, and waking were scored for each 15-s period of the EEG recordings. During the prestress period, rats slept (REM plus NREM) 55% of available time during the light hours and 34% of the dark hours with the remainder represented by waking. On the first day of stress, total sleep and, especially REM sleep, decreased markedly. By the second day of stress, only REM sleep in the controllable stress group (but not the uncontrollable stress group) was still significantly decreased compared to prestress levels, and REM sleep returned to baseline levels by day 7 of stress. The recovery of sleep quantity was accomplished by increased sleep during the dark hours, resulting in a long-lasting disruption of normal circadian sleep patterning.

  2. Effective stress law for anisotropic double porous media

    Institute of Scientific and Technical Information of China (English)

    ZHAO Ying; CHEN Mian; ZHANG Guangqing

    2004-01-01

    An effective stress law is derived analytically to describe the effect of pore (fracture pore and matrix-block pore) fluid pressure on the linearly elastic response of anisotropic saturated dual-porous rocks, which exhibit anisotropy. For general anisotropy the difference between the effective stress and the applied stress is not hydrostatic simply multiplied by Biot coefficient. The effective stress law involves four constants for transversely isotropic response; these constants can be expressed in terms of the moduli of the single porous material, double porous material and of the solid material. These expressions are simplified considerably when the anisotropy is structural rather than intrinsic, i.e. in the case of an isotropic solid material with an anisotropic pore structure. In this case the effective stress law involves grain bulk modulus, four moduli and two compliances of the porous material for transverse isotropy. The law reduces, in the case of isotropic response, to that suggested by Li Shuiquan (2001). And reduction to the single-porosity (derived analytically by Carroll (1979)) is presented to demonstrate the conceptual consistency of the proposed law.

  3. The impact of stress on tumor growth: peripheral CRF mediates tumor-promoting effects of stress

    Directory of Open Access Journals (Sweden)

    Stathopoulos Efstathios N

    2010-09-01

    effect. Moreover, antalarmin suppressed neoangiogenesis in 4T1 tumors in vivo. Conclusion This is the first report demonstrating that peripheral CRF, at least in part, mediates the tumor-promoting effects of stress and implicates CRF in SMAD2 and β-catenin expression.

  4. Bias explains most of the parent-of-origin effect on breast cancer risk in BRCA1/2 mutation carriers

    NARCIS (Netherlands)

    Vos, Janet R; Oosterwijk, Jan C; Aalfs, Cora M; Rookus, Matti A; Adank, Muriel A; van der Hout, Annemarie H; van Asperen, Christi J; Gomez-Garcia, Encarna B; Mensenkamp, Arjen R; Jager, Agnes; Ausems, Margreet G E M; Mourits, Marian J; de Bock, Geertruida H

    2016-01-01

    BACKGROUND: Paternal transmission of a BRCA mutation has been reported to increase the risk of breast cancer in offspring more than when the mutation is maternally inherited. As this effect might be caused by referral bias, the aim of this study was to assess the parent-of-origin effect of the BRCA1

  5. The relationship between level of autistic traits and local bias in the context of the McGurk effect.

    Directory of Open Access Journals (Sweden)

    Yuta eUjiie

    2015-06-01

    Full Text Available The McGurk effect is a well-known illustration that demonstrates the influence of visual information on hearing in the context of speech perception. Some studies have reported that individuals with autism spectrum disorder (ASD display abnormal processing of audio-visual speech integration, while other studies showed contradictory results. Based on the dimensional model of ASD, we administered two analog studies to examine the link between level of autistic traits, as assessed by the Autism Spectrum Quotient (AQ, and the McGurk effect among a sample of university students. In the first experiment, we found that autistic traits correlated negatively with fused (McGurk responses. Then, we manipulated presentation types of visual stimuli to examine whether the local bias toward visual speech cues modulated individual differences in the McGurk effect. The presentation included four types of visual images, comprising no image, mouth only, mouth and eyes, and full face. The results revealed that global facial information facilitates the influence of visual speech cues on McGurk stimuli. Moreover, individual differences between groups with low and high levels of autistic traits appeared when the full-face visual speech cue with an incongruent voice condition was presented. These results suggest that individual differences in the McGurk effect might be due to a weak ability to process global facial information in individuals with high levels of autistic traits.

  6. Effect of field cooling process and ion-beam bombardment on the exchange bias of NiCo/(Ni, Co)O bilayers

    Energy Technology Data Exchange (ETDEWEB)

    Li, X. [Department of Electrical and Electronic Engineering, The University of Hong Kong (Hong Kong); Lin, K.-W., E-mail: kwlin@dragon.nchu.edu.tw [Department of Materials Science and Engineering, National Chung Hsing University, Taichung 402, Taiwan (China); Liu, H.-Y. [Department of Materials Science and Engineering, National Chung Hsing University, Taichung 402, Taiwan (China); Wei, D.-H. [National Synchrotron Radiation Research Center, Hsinchu 300, Taiwan (China); Li, G.J. [Department of Electrical and Electronic Engineering, The University of Hong Kong (Hong Kong); Pong, P.W.T., E-mail: ppong@eee.hku.hk [Department of Electrical and Electronic Engineering, The University of Hong Kong (Hong Kong)

    2014-11-03

    The research on exchange coupled ferromagnetic/antiferromagnetic (FM/AF) bilayers has been the foundation of spintronic applications such as hard disk reading heads and spin torque oscillators. In order to further explore the exchange bias behavior of NiCo/(Ni, Co)O bilayers, effect of field cooling process, magnetic angular dependence, and ion-beam bombardment was investigated. The difference in film composition resulted in remarkable distinction in crystalline structures and domain patterns. The exchange bias field (H{sub ex}) in the bilayer systems exhibited a strong angular dependence. The negative H{sub ex} after a field cooling process indicated that the polarity of H{sub ex} can be defined by aligning the magnetization orientation of the FM NiCo layer with the applied field. Moreover, enhanced exchange bias effect was observed in the NiCo/(Ni, Co)O bilayers that resulted from the surface of the (Ni, Co)O layers bombarded with different Ar{sup +} ion-beam energies using End-Hall voltages from 0 V to 150 V. The interface spin structures as well as the surface domain patterns were altered by the ion-beam bombardment process. These results indicated that the exchange bias field of NiCo/(Ni, Co)O bilayer systems could be tailored by field cooling process, angular dependence of magnetic properties, and post ion-beam bombardment. - Highlights: • Strong angular dependence was observed in the exchange bias of NiCo/(Ni, Co)O bilayers. • The field cooling process resulted in negative exchange bias. • Moderate ion-beam bombardment on (NiCo)O layers enhanced exchange bias at 298 K. • High-energy ion bombardment strengthened the exchange coupling in field cooled bilayer. • The structural deformation was responsible for the change in magnetic properties.

  7. Antidepressant and anti-stress effects of curcumin inmice

    Institute of Scientific and Technical Information of China (English)

    YingXU; Bao-shanKU; Hai-yanYAO; Yong-heZHANG; Xue-junLI

    2004-01-01

    Curcumin (diferuloylmethane), a yellow colouring agent contained in the rhizome of Curcuma Longa (turmeric), has a wide array of pharmacological and biological activities, such as antioxidant, anti-inflammatory, immunomodulating and anticarcinogenic effects. In this study, curcumin was examined for the antidepressant and anti-stress effects in forced swimming,

  8. Testing for potential contextual bias effects during the verification stage of the ACE-V methodology when conducting fingerprint comparisons.

    Science.gov (United States)

    Langenburg, Glenn; Champod, Christophe; Wertheim, Pat

    2009-05-01

    This study was conducted to assess if fingerprint specialists could be influenced by extraneous contextual information during a verification process. Participants were separated into three groups: a control group (no contextual information was given), a low bias group (minimal contextual information was given in the form of a report prompting conclusions), and a high bias group (an internationally recognized fingerprint expert provided conclusions and case information to deceive this group into believing that it was his case and conclusions). A similar experiment was later conducted with laypersons. The results showed that fingerprint experts were influenced by contextual information during fingerprint comparisons, but not towards making errors. Instead, fingerprint experts under the biasing conditions provided significantly fewer definitive and erroneous conclusions than the control group. In contrast, the novice participants were more influenced by the bias conditions and did tend to make incorrect judgments, especially when prompted towards an incorrect response by the bias prompt.

  9. Sex bias in infectious disease epidemiology: patterns and processes.

    Directory of Open Access Journals (Sweden)

    Felipe Guerra-Silveira

    Full Text Available BACKGROUND: Infectious disease incidence is often male-biased. Two main hypotheses have been proposed to explain this observation. The physiological hypothesis (PH emphasizes differences in sex hormones and genetic architecture, while the behavioral hypothesis (BH stresses gender-related differences in exposure. Surprisingly, the population-level predictions of these hypotheses are yet to be thoroughly tested in humans. METHODS AND FINDINGS: For ten major pathogens, we tested PH and BH predictions about incidence and exposure-prevalence patterns. Compulsory-notification records (Brazil, 2006-2009 were used to estimate age-stratified ♂:♀ incidence rate ratios for the general population and across selected sociological contrasts. Exposure-prevalence odds ratios were derived from 82 published surveys. We estimated summary effect-size measures using random-effects models; our analyses encompass ∼0.5 million cases of disease or exposure. We found that, after puberty, disease incidence is male-biased in cutaneous and visceral leishmaniasis, schistosomiasis, pulmonary tuberculosis, leptospirosis, meningococcal meningitis, and hepatitis A. Severe dengue is female-biased, and no clear pattern is evident for typhoid fever. In leprosy, milder tuberculoid forms are female-biased, whereas more severe lepromatous forms are male-biased. For most diseases, male bias emerges also during infancy, when behavior is unbiased but sex steroid levels transiently rise. Behavioral factors likely modulate male-female differences in some diseases (the leishmaniases, tuberculosis, leptospirosis, or schistosomiasis and age classes; however, average exposure-prevalence is significantly sex-biased only for Schistosoma and Leptospira. CONCLUSIONS: Our results closely match some key PH predictions and contradict some crucial BH predictions, suggesting that gender-specific behavior plays an overall secondary role in generating sex bias. Physiological differences, including

  10. Cognitive Bias in Systems Verification

    Science.gov (United States)

    Larson, Steve

    2012-01-01

    Working definition of cognitive bias: Patterns by which information is sought and interpreted that can lead to systematic errors in decisions. Cognitive bias is used in diverse fields: Economics, Politics, Intelligence, Marketing, to name a few. Attempts to ground cognitive science in physical characteristics of the cognitive apparatus exceed our knowledge. Studies based on correlations; strict cause and effect is difficult to pinpoint. Effects cited in the paper and discussed here have been replicated many times over, and appear sound. Many biases have been described, but it is still unclear whether they are all distinct. There may only be a handful of fundamental biases, which manifest in various ways. Bias can effect system verification in many ways . Overconfidence -> Questionable decisions to deploy. Availability -> Inability to conceive critical tests. Representativeness -> Overinterpretation of results. Positive Test Strategies -> Confirmation bias. Debiasing at individual level very difficult. The potential effect of bias on the verification process can be managed, but not eliminated. Worth considering at key points in the process.

  11. Publication bias in epidemiological studies.

    Science.gov (United States)

    Siddiqi, Nazish

    2011-06-01

    Communication of research findings is the utmost responsibility of all scientists. Publication bias occurs if scientific studies with negative or null results fail to get published. This can happen due to bias in submitting, reviewing, accepting, publishing or aggregating scientific literature that fails to show positive results on a particular topic. Publication bias can make scientific literature unrepresentative of the actual research studies. This can give the reader a false impression about the beneficial effects of a particular treatment or intervention and can influence clinical decision making. Publication bias is more common than it is actually considered to be, but there are ways to detect and prevent it. This paper comments on the occurrence, types and consequences of publication bias and the strategies employed to detect and control it.

  12. Stress effects on coarticulation in English and Greek

    Science.gov (United States)

    Koenig, Laura; Okalidou, Areti

    2003-04-01

    The effects of stress on production variability and V-to-V coarticulation were compared in American English and Greek, two languages which differ in vowel inventory size and in the magnitude of V-to-V coarticulation (Okalidou and Koenig, 1999). Six speakers, one male and two females from each language, were recorded producing nonsense VCV utterances in a carrier phrase, with randomly alternating stress. The Greek stimuli included all five vowels of the language; the English stimuli included the closest counterparts of the Greek vowels. The medial plosive consonants alternated between the bilabial and alveolar place of articulation, yielding different degrees of coarticulatory resistance (Recasens, 1985, 1989). Plosives were chosen to have similar VOT values across languages in order to minimize duration effects. A comparison of stressed versus unstressed vowel areas reveals significant differences across languages. Specific vowel effects and language effects are also noted with respect to changes in production variability under the stressed versus unstressed conditions. The magnitude of V-to-V influences as a function of stress and position is discussed in terms of the above crosslinguistic comparison in order to obtain further insight on the coarticulatory behavior of languages which differ in the size of vowel inventory (Manuel and Krakow, 1984).

  13. Avoiding the Approach Trap: A Response Bias Theory of the Emotional Stroop Effect

    Science.gov (United States)

    Chajut, Eran; Mama, Yaniv; Levy, Leora; Algom, Daniel

    2010-01-01

    In the laboratory, people classify the color of emotion-laden words slower than they do that of neutral words, the emotional Stroop effect. Outside the laboratory, people react to features of emotion-laden stimuli or threatening stimuli faster than they do to those of neutral stimuli. A possible resolution to the conundrum implicates the…

  14. An Investigation of Biases and Framing Effects for Risk Analysis: An Information Technology Context

    Science.gov (United States)

    Fox, Stuart A.

    2012-01-01

    An elusive and problematic theme of risk management has been managers' ability to effectively measure information technology (IT) risk in terms of degree of impact and probability of occurrence. The background of this problem delves deep into the rational understanding of probability, expected value, economic behavior, and subjective judgment.…

  15. Gender bias in beliefs on physical activity: Buffering effects of sport participation among girls

    Science.gov (United States)

    The purpose of this study was to determine effects of child gender on parental and child beliefs and evaluate competitive sport participation as a modifier of child beliefs. Two age-groups of children and parents completed measures on child athletic appearance, competence, importance of physical act...

  16. Phantom Behavioral Assimilation Effects : Systematic Biases in Social Comparison Choice Studies

    NARCIS (Netherlands)

    Marsh, Herbert W.; Seaton, Marjorie; Kuyper, Hans; Dumas, Florence; Huguet, Pascal; Regner, Isabelle; Buunk, Abraham P.; Monteil, Jean-Marc; Gibbons, Frederick X.

    2010-01-01

    Consistent with social comparison theory (SCT), Blanton, Buunk, Gibbons, and Kuyper (1999) and Huguet, Dumas, Monteil, and Genestoux (2001) found that students tended to choose comparison targets who slightly outperformed them (i.e., upward comparison choices), and this had a beneficial effect on su

  17. Some general effects of strong high-frequency excitation: stiffening, biasing, and smoothening

    DEFF Research Database (Denmark)

    Thomsen, Jon Juel

    2002-01-01

    Mechanical high-frequency (HF) excitation provides a working principle behind many industrial and natural applications and phenomena. This paper concerns three particular effects of HF excitation, that may change the apparent characteristics of mechanical systems: 1) stiffening, by which the appa...

  18. Effectiveness of stress management training on stress reduction in pregnant women

    Directory of Open Access Journals (Sweden)

    Mahboobeh Shirazi

    2016-10-01

    .1 for moderated level stress (P= 0.001 and 40.1 to 16.6 for high level of stress (P= 0.0001 respectively. Conclusion: First trimester of pregnancy is a crucial stage of fetal growth and development. Based on our findings, stress management training in this period has beneficial effects on stress reduction and enhances maternal health status.

  19. Parameter estimation biases due to contributions from the Rees-Sciama effect to the integrated Sachs-Wolfe spectrum

    CERN Document Server

    Schaefer, Bjoern Malte; Heisenberg, Lavinia

    2010-01-01

    The subject of this paper is an investigation of the nonlinear contributions to the spectrum of the integrated Sachs-Wolfe (iSW) effect. We derive the corrections to the iSW-auto spectrum and the iSW-tracer cross-spectrum consistently to third order in perturbation theory and analyse the cumulative signal-to-noise ratio for a cross-correlation between the PLANCK and EUCLID data sets as a function of multipole order. We quantify the parameter sensitivity and the statistical error bounds on the cosmological parameters Omega_m, sigma_8, h, n_s and w from the linear iSW-effect and the systematical parameter estimation bias due to the nonlinear corrections in a Fisher-formalism, analysing the error budget in its dependence on multipole order. Our results include: (i) the spectrum of the nonlinear iSW-effect can be measured with 0.8\\sigma statistical significance, (ii) nonlinear corrections dominate the spectrum starting from l=100, (iii) an anticorrelation of the CMB temperature with tracer density on high multipo...

  20. Investigating the effect of anxiety sensitivity, gender and negative interpretative bias on the perception of chest pain.

    Science.gov (United States)

    Keogh, Edmund; Hamid, Rayhana; Hamid, Shahid; Ellery, Deborah

    2004-09-01

    Research suggests that anxiety sensitivity may be an important component in the negative response to pain sensations, especially those with cardiopulmonary origin. Furthermore, there is experimental evidence to suggest that such effects may be stronger in women than men. The primary aim of the current investigation was to determine the relative roles that anxiety sensitivity and gender have on the pain reports of patients referred to a hospital clinic with chest pain. A total of 78 female and 76 male adults were recruited on entry to a Rapid Access Medical Clinic. All patients had been referred with chest pain, and were administered a range of pain and anxiety measures prior to diagnosis. Results indicate that males were more likely to receive a diagnosis of cardiac chest pain, whereas females were more likely to receive a diagnosis of non-cardiac chest pain. Additionally, anxiety sensitivity was related to pain in women but not men. Finally, evidence was found for the mediating effect of negative interpretative bias on the relationship between anxiety sensitivity and pain. However, this mediating effect was only found in women. These results not only confirm that anxiety sensitivity is related to greater negative pain responses in women, but that this may be due to an increased tendency to negatively interpret sensations.

  1. Content Effects in Mathematics Problem Solving. A Possible Source of Test Bias?

    Science.gov (United States)

    1991-04-15

    it is usually in tests or subtests of mathematics word problems (Chipman & Thomas, 1985; Chipman, 1988; Hyde, Fennema & Lamon, 1990). The diversity and...8217- Content Effects 2 males or females (Chipman, 1988). For example, one study may report that females do worse on geometry items ( Fennema & 4Carpenter...in mathematics anxiety/confidence (Chipman & Wilson, 1985; Hyde, Fennema , Ryan, Frost & Hopp, 1990) may make females more prone to omit problems that

  2. Affective verbal learning in hostility: an increased primacy effect and bias for negative emotional material.

    Science.gov (United States)

    Mollet, Gina A; Harrison, David W

    2007-01-01

    The current experiment examined the effects of hostility and a pain stressor on affective verbal learning. Participants were classified as high or low hostile and randomly assigned to a cold pressor or a non-cold pressor group. The subsequent effects on acquisition of the Auditory Affective Verbal Learning Test [AAVLT; Snyder, K. A., & Harrison, D. W. (1997). The Affective Verbal Learning Test. Archives of Clinical Neuropsychology, 12(5), 477-482] were measured. As expected, high hostiles learned negative emotional words significantly better than they learned positive words. Additionally, high hostiles were impaired in their acquisition of verbal material relative to low hostile participants. A significant primacy effect for negative emotional words and an overall better recall of negative information was also found. These results support the idea that high hostiles differ from low hostiles in a number of modalities and demonstrate the persistence of negative emotional material. Future work should address the implications these results have on high hostiles in daily interactions.

  3. The pulling power of chocolate: Effects of approach-avoidance training on approach bias and consumption.

    Science.gov (United States)

    Dickson, Hugh; Kavanagh, David J; MacLeod, Colin

    2016-04-01

    Previous research has shown that action tendencies to approach alcohol may be modified using computerized Approach-Avoidance Task (AAT), and that this impacted on subsequent consumption. A recent paper in this journal (Becker, Jostman, Wiers, & Holland, 2015) failed to show significant training effects for food in three studies: Nor did it find effects on subsequent consumption. However, avoidance training to high calorie foods was tested against a control rather than Approach training. The present study used a more comparable paradigm to the alcohol studies. It randomly assigned 90 participants to 'approach' or 'avoid' chocolate images on the AAT, and then asked them to taste and rate chocolates. A significant interaction of condition and time showed that training to avoid chocolate resulted in faster avoidance responses to chocolate images, compared with training to approach it. Consistent with Becker et al.'s Study 3, no effect was found on amounts of chocolate consumed, although a newly published study in this journal (Schumacher, Kemps, & Tiggemann, 2016) did do so. The collective evidence does not as yet provide solid basis for the application of AAT training to reduction of problematic food consumption, although clinical trials have yet to be conducted.

  4. Antioxidant Effects of Some Drugs on Immobilization Stress Combined with Cold Restraint Stress

    Directory of Open Access Journals (Sweden)

    Svetlana Trivic

    2009-11-01

    Full Text Available The aim of this work was to investigate the effect on antioxidant potential of some commonly used drugs (morphine, tramadol, bromocriptine, haloperidol and azithromycin on immobilization stress (IS combined with cold restraint stress (CRS in the rat. After the drug treatment the animals were kept immobilized in the cold chamber at 4±0.3ºC for 3 hours and then decapitaed and the livers were extracted. The following parameters were determined in the liver homogenate: content of reduced glutathione, activities of catalase, xanthine oxidase, glutathione reductase, glutathione peroxidase, peroxidase, and lipid peroxidation intensity. A battery of biochemical assays was used and the resulting data were statistically analyzed. Combined stress exhibited a prooxidative action (increased catalase activity, lowered content of reduced glutathione. Significantly enhanced catalase activity that was observed in all groups compared to the control indicates that the primary reactive oxygen species (ROS metabolite is hydrogen peroxide, which decomposes very rapidly (very high catalase activity, thus hindering formation of OH radicals as the most toxic ROS. None of the tested drugs showed a protective effect on combined IS and CRS. The intensity of lipid peroxidation did not change either in the combined stress or under additional influence of the drugs. Probably, under our experimental conditions, the time was not sufficiently long to observe damage of lipid membrane by ROS.

  5. Neuroprotective effects of sildenafil against oxidative stress and memory dysfunction in mice exposed to noise stress.

    Science.gov (United States)

    Sikandaner, Hu Erxidan; Park, So Young; Kim, Min Jung; Park, Shi Nae; Yang, Dong Won

    2017-02-15

    Noise exposure has been well characterized as an environmental stressor, and is known to have auditory and non-auditory effects. Phosphodiesterase 5 (PDE5) inhibitors affect memory and hippocampus plasticity through various signaling cascades which are regulated by cGMP. In this study, we investigated the effects of sildenafil on memory deficiency, neuroprotection and oxidative stress in mice caused by chronic noise exposure. Mice were exposed to noise for 4h every day up to 14days at 110dB SPL of noise level. Sildenafil (15mg/kg) was orally administered 30min before noise exposure for 14days. Behavioral assessments were performed using novel object recognition (NOR) test and radial arm maze (RAM) test. Higher levels of memory dysfunction and oxidative stress were observed in noise alone-induced mice compared to control group. Interestingly, sildenafil administration increased memory performance, decreased oxidative stress, and increased neuroprotection in the hippocampus region of noise alone-induced mice likely through affecting memory related pathways such as cGMP/PKG/CREB and p25/CDK5, and induction of free radical scavengers such as SOD1, SOD2, SOD3, Prdx5, and catalase in the brain of stressed mice.

  6. The effect of occupational stress, psychological stress and burnout on employee performance: Evidence from banking industry

    Directory of Open Access Journals (Sweden)

    Shahram Hashemnia

    2014-09-01

    Full Text Available This paper presents an empirical investigation on the effects of occupational stress, psychological stress as well as job burnout on women’s employee performance in city of Karaj, Iran. The proposed study designs a questionnaire in Likert scale and distributes it among all female employees who worked for Bank Maskan in this city. In our survey, employee performance consists of three parts of interpersonal performance, job performance as well as organizational performance. Cronbach alpha has been used to verify the overall questionnaire, all components were within acceptable levels, and the implementation of Kolmogorov-Smirnov test has indicated that the data were not normally distributed. Using Spearman correlation ratio as well as regression techniques, the study has determined that while psychological stress influenced significantly on all three components of employee performance including interpersonal performance, job performance as well as organizational performance, the effect on job performance was greater than the other components. In addition, occupational stress only influences on organizational as well as interpersonal performance. Finally, employee burnout has no impact on any components of employee performance.

  7. Investigation of temperature effect on stress of flexspline

    Institute of Scientific and Technical Information of China (English)

    项青; 尹征南

    2014-01-01

    The effect of temperature loading on the stress of a flexspline is investigated. Based on the geometric and mechanical characteristics of the harmonic gear flexspline, a circular thin shell model is presented in this paper. The theoretical solution for the flexspline under different displacement loads and different temperature fields is derived. Meanwhile, an impact factor formula, which reflects the effect of the temperatures of the inner and outer surfaces of the flexspline on the stress of the flexspline, is presented. Finally, numerical calculations by the finite element method (FEM) are adopted to verify the corresponding conclusions.

  8. Effect of mindfulness-based stress reduction on sleep quality

    DEFF Research Database (Denmark)

    Andersen, Signe; Würtzen, Hanne; Steding-Jessen, Marianne;

    2013-01-01

    The prevalence of sleep disturbance is high among cancer patients, and the sleep problems tend to last for years after the end of treatment. As part of a large randomized controlled clinical trial (the MICA trial, NCT00990977) of the effect of mindfulness-based stress reduction (MBSR) on psycholo......The prevalence of sleep disturbance is high among cancer patients, and the sleep problems tend to last for years after the end of treatment. As part of a large randomized controlled clinical trial (the MICA trial, NCT00990977) of the effect of mindfulness-based stress reduction (MBSR...

  9. Effects of lifetime stress exposure on mental and physical health in young adulthood: How stress degrades and forgiveness protects health.

    Science.gov (United States)

    Toussaint, Loren; Shields, Grant S; Dorn, Gabriel; Slavich, George M

    2016-06-01

    To examine risk and resilience factors that affect health, lifetime stress exposure histories, dispositional forgiveness levels, and mental and physical health were assessed in 148 young adults. Greater lifetime stress severity and lower levels of forgiveness each uniquely predicted worse mental and physical health. Analyses also revealed a graded Stress × Forgiveness interaction effect, wherein associations between stress and mental health were weaker for persons exhibiting more forgiveness. These data are the first to elucidate the interactive effects of cumulative stress severity and forgiveness on health, and suggest that developing a more forgiving coping style may help minimize stress-related disorders.

  10. Male-biased autosomal effect of 16p13.11 copy number variation in neurodevelopmental disorders.

    Directory of Open Access Journals (Sweden)

    Maria Tropeano

    Full Text Available Copy number variants (CNVs at chromosome 16p13.11 have been associated with a range of neurodevelopmental disorders including autism, ADHD, intellectual disability and schizophrenia. Significant sex differences in prevalence, course and severity have been described for a number of these conditions but the biological and environmental factors underlying such sex-specific features remain unclear. We tested the burden and the possible sex-biased effect of CNVs at 16p13.11 in a sample of 10,397 individuals with a range of neurodevelopmental conditions, clinically referred for array comparative genomic hybridisation (aCGH; cases were compared with 11,277 controls. In order to identify candidate phenotype-associated genes, we performed an interval-based analysis and investigated the presence of ohnologs at 16p13.11; finally, we searched the DECIPHER database for previously identified 16p13.11 copy number variants. In the clinical referral series, we identified 46 cases with CNVs of variable size at 16p13.11, including 28 duplications and 18 deletions. Patients were referred for various phenotypes, including developmental delay, autism, speech delay, learning difficulties, behavioural problems, epilepsy, microcephaly and physical dysmorphisms. CNVs at 16p13.11 were also present in 17 controls. Association analysis revealed an excess of CNVs in cases compared with controls (OR = 2.59; p = 0.0005, and a sex-biased effect, with a significant enrichment of CNVs only in the male subgroup of cases (OR = 5.62; p = 0.0002, but not in females (OR = 1.19, p = 0.673. The same pattern of results was also observed in the DECIPHER sample. Interval-based analysis showed a significant enrichment of case CNVs containing interval II (OR = 2.59; p = 0.0005, located in the 0.83 Mb genomic region between 15.49-16.32 Mb, and encompassing the four ohnologs NDE1, MYH11, ABCC1 and ABCC6. Our data confirm that duplications and deletions at 16p13

  11. Effect of Particle Size on Shear Stress of Magnetorheological Fluids

    Directory of Open Access Journals (Sweden)

    Chiranjit Sarkar

    2015-05-01

    Full Text Available Magnetorheological fluids (MRF, known for their variable shear stress contain magnetisable micrometer-sized particles (few micrometer to 200 micrometers in a nonmagnetic carrier liquid. To avoid settling of particles, smaller sized (3-10 micrometers particles are preferred, while larger sized particles can be used in MR brakes, MR clutches, etc. as mechanical stirring action in those mechanisms does not allow particles to settle down. Ideally larger sized particles provide higher shear stress compared to smaller sized particles. However there is need to explore the effect of particle sizes on the shear stress. In the current paper, a comparison of different particle sizes on MR effect has been presented. Particle size distributions of iron particles were measured using HORIBA Laser Scattering Particle Size Distribution Analyser. The particle size distribution, mean sizes and standard deviations have been presented. The nature of particle shapes has been observed using scanning electron microscopy. To explore the effect of particle sizes, nine MR fluids containing small, large and mixed sized carbonyl iron particles have been synthesized. Three concentrations (9%, 18% and 36% by volume for each size of particles have been used. The shear stresses of those MRF samples have been measured using ANTON PAAR MCR-102 Rheometer. With increase in volume fraction of iron particles, the MR fluids synthesized using “mixed sized particles” show better shear stress compared to the MR fluids containing “smaller sized spherical shaped particles” and “larger sized flaked shaped particles” at higher shear rate.

  12. Study of stress, self-esteem and depression in medical students and effect of music on perceived stress.

    Science.gov (United States)

    Baste, Vrushali S; Gadkari, Jayashree V

    2014-01-01

    Medical students are exposed to many stressors and if stress is perceived negatively or becomes excessive can affect academic performance and health adversely. The objective of this study was to assess stress, predominant stressor and effect of music on perceived stress. 90 undergraduate students were selected randomly. A written questionnaire about personal information, stressful factors, ways to cope up stress, Rosenberg self-esteem scale (Rosenberg, 1965) and 'Quick Inventory of Depressive Symptomatology' self-rated 16 (QIDS-SR-16) was given.45.6% Students had mild stress, 7.7% students had moderate stress and 1.1% students had severe stress. Academic factors were the predominant cause of stress in most students, followed by physical, social and emotional. On Rosenberg self-esteem scale (Rosenberg, 1965) 85.6% students had high self-esteem and on QIDS-SR16 50% students had depression. Effect of music on perceived stress was statistically significant. Medical curriculum is associated with increased stress in students. Music can be used as simple, inexpensive and effective therapy for stress.

  13. Effect of Flavonoids on Oxidative Stress and Inflammation in Adults at Risk of Cardiovascular Disease: A Systematic Review

    Science.gov (United States)

    Suen, Jenni; Thomas, Jolene; Kranz, Amelia; Vun, Simon; Miller, Michelle

    2016-01-01

    Oxidative stress (OS) and inflammatory processes initiate the first stage of cardiovascular disease (CVD). Flavonoid consumption has been related to significantly improved flow-mediated dilation and blood pressure. Antioxidant and anti-inflammatory mechanisms are thought to be involved. The effect of flavonoids on markers of oxidative stress and inflammation, in at risk individuals is yet to be reviewed. Systematic literature searches were conducted in MEDLINE, Cochrane Library, CINAHL and SCOPUS databases. Randomised controlled trials in a Western country providing a food-based flavonoid intervention to participants with one or two modifiable risk factors for CVD measuring a marker of OS and/or inflammation, were included. Reference lists were hand-searched. The Cochrane Collaboration Risk of Bias Tool was used to assess study quality. The search strategy retrieved 1248 articles. Nineteen articles meeting the inclusion criteria were reviewed. Eight studies were considered at low risk of bias. Cocoa flavonoids provided to Type 2 diabetics and olive oil flavonoids to mildly-hypertensive women reduced OS and inflammation. Other food sources had weaker effects. No consistent effect on OS and inflammation across patients with varied CVD risk factors was observed. Study heterogeneity posed a challenge for inter-study comparisons. Rigorously designed studies will assist in determining the effectiveness of flavonoid interventions for reducing OS and inflammation in patients at risk of CVD. PMID:27649255

  14. Gate Bias Effects on Samples with Edge Gates in the Quantum Hall Regime

    OpenAIRE

    若林 淳一; 風間 重雄; 長嶋 登志夫

    2001-01-01

    We have fabricated GaAs/AlGaAs heterostructure Hall samples that have edge gate with several widths along both sides of the sample. The gate width dependence of an effect of the gate voltage to the Hall resistance was measured at the middle of a transition region between the adjacent quantum Hall plateaus. The results have been analyzed based on two model functions of current distribution;an exponential type and the modified Beenakker type. The results of the former have shown qualitative agr...

  15. Large scale environmental bias of the QSO line of sight proximity effect

    CERN Document Server

    Partl, Adrian M; Yepes, Gustavo; Gottlöber, Stefan

    2011-01-01

    We analyse the proximity zone of the intergalactic matter around high-redshift quasars in a cosmological environment. In a box of 64 h-1 Mpc base length we employ dark matter only simulations. For estimating the hydrogen temperature and density distribution we use the effective equation of state. Hydrogen is assumed to be in photoionisation equilibrium with a model background flux which is fit to recent observations of the mean optical depth and transmission flux statistics. At redshifts z = 3, 4, and 4.8, we select model quasar positions at the centre of the 20 most massive halos and 100 less massive halos identified in the simulation. From each assumed quasar position we cast 100 random lines of sight for two box length including the changes in the ionisation fractions by the QSO flux field and derive mock Ly{\\alpha} spectra. The proximity effect describes the dependence of the mean normalised optical depth {\\xi} = {\\tau}eff, QSO/{\\tau}eff, Ly{\\alpha} as a function of the ratio of the ionisation rate by the...

  16. Biased total mass of cool core galaxy clusters by Sunyaev-Zel'dovich Effect measurements

    CERN Document Server

    Conte, A; Comis, B; Lamagna, L; De Gregori, S

    2010-01-01

    The Sunyaev Zel'dovich (SZ) effect is one of the most powerful cosmological tools to investigate the large-scale Universe, in which clusters of galaxies are the most interesting target. The great advantage of the SZ effect of being redshift independent, in contrast with visible and X-ray observations, allows to directly estimate cluster total mass from the integrated comptonization parameter Y, even for faraway clusters. However, the lack of a complete knowledge of the Intra-Cluster gas (ICg) physics can affect the results. Taking into account self-similar temperature and density profiles of the ICg, we study how different ICg morphologies can affect the cluster total mass estimation. Due to the large percentage of cool core (CC) clusters, we analyze this class starting with a limited sample of eight objects, observed by Chandra. We simulate SZ observations of these clusters through X-ray derived information, and re-analyze the mock SZ data with the simplistic assumption for the ICg of an isothermal beta mode...

  17. Theoretical analysis and an improvement method of the bias effect on the linearity of RF linear power amplifiers

    Institute of Scientific and Technical Information of China (English)

    Wu Tuo; Chen Hongyi; Qian Dahong

    2009-01-01

    Based on the Gummel-Poon model of BJT, the change of the DC bias as a function of the AC input signal in RF linear power amplifiers is theoretically derived, so that the linearity of different DC bias circuits can be interpreted and compared. According to the analysis results, a quantitative adaptive DC bias circuit is proposed,which can improve the linearity and efficiency. From the simulation and test results, we draw conclusions on how to improve the design of linear power amplifier.

  18. Stress and its effects on horses reproduction

    OpenAIRE

    Amal M. AboEl-Maaty

    2011-01-01

    A total of 90 mares and horses were subjected to blood sampling for determining the effect of management (farm), reproductive condition, sex, age, breed and month of the year during breeding on circulating levels of cortisol and sex hormones. Blood samples were collected from December to the following June from four farms. Blood sera underwent testosterone, estradiol, progesterone and cortisol assaying using ELISA kits. Cortisol levels were significantly low in lactating mares during their fo...

  19. Confirmation of a Star Formation Bias in Type Ia Supernova Distances and its Effect on Measurement of the Hubble Constant

    CERN Document Server

    Rigault, M; Kowalski, M; Copin, Y; Antilogus, P; Aragon, C; Bailey, S; Baltay, C; Baugh, D; Bongard, S; Boone, K; Buton, C; Chen, J; Chotard, N; Fakhouri, H K; Feindt, U; Fagrelius, P; Fleury, M; Fouchez, D; Gangler, E; Hayden, B; Kim, A G; Leget, P -F; Lombardo, S; Nordin, J; Pain, R; Pecontal, E; Pereira, R; Perlmutter, S; Rabinowitz, D; Runge, K; Rubin, D; Saunders, C; Smadja, G; Sofiatti, C; Suzuki, N; Tao, C; Weaver, B A

    2014-01-01

    Previously we used the Nearby Supernova Factory sample to show that SNe~Ia having locally star-forming environments are dimmer than SNe~Ia having locally passive environments.Here we use the \\constitution\\ sample together with host galaxy data from \\GALEX\\ to independently confirm that result. The effect is seen using both the SALT2 and MLCS2k2 lightcurve fitting and standardization methods, with brightness differences of $0.094 \\pm 0.037\\ \\mathrm{mag}$ for SALT2 and $0.155 \\pm 0.041\\ \\mathrm{mag}$ for MLCS2k2 with $R_V=2.5$. When combined with our previous measurement the effect is $0.094 \\pm 0.025\\ \\mathrm{mag}$ for SALT2. If the ratio of these local SN~Ia environments changes with redshift or sample selection, this can lead to a bias in cosmological measurements. We explore this issue further, using as an example the direct measurement of $H_0$. \\GALEX{} observations show that the SNe~Ia having standardized absolute magnitudes calibrated via the Cepheid period--luminosity relation using {\\textit{HST}} orig...

  20. Negativity Bias in Media Multitasking: The Effects of Negative Social Media Messages on Attention to Television News Broadcasts.

    Directory of Open Access Journals (Sweden)

    Jari Kätsyri

    Full Text Available Television viewers' attention is increasingly more often divided between television and "second screens", for example when viewing television broadcasts and following their related social media discussion on a tablet computer. The attentional costs of such multitasking may vary depending on the ebb and flow of the social media channel, such as its emotional contents. In the present study, we tested the hypothesis that negative social media messages would draw more attention than similar positive messages. Specifically, news broadcasts were presented in isolation and with simultaneous positive or negative Twitter messages on a tablet to 38 participants in a controlled experiment. Recognition memory, gaze tracking, cardiac responses, and self-reports were used as attentional indices. The presence of any tweets on the tablet decreased attention to the news broadcasts. As expected, negative tweets drew longer viewing times and elicited more attention to themselves than positive tweets. Negative tweets did not, however, decrease attention to the news broadcasts. Taken together, the present results demonstrate a negativity bias exists for social media messages in media multitasking; however, this effect does not amplify the overall detrimental effects of media multitasking.

  1. Negativity Bias in Media Multitasking: The Effects of Negative Social Media Messages on Attention to Television News Broadcasts.

    Science.gov (United States)

    Kätsyri, Jari; Kinnunen, Teemu; Kusumoto, Kenta; Oittinen, Pirkko; Ravaja, Niklas

    2016-01-01

    Television viewers' attention is increasingly more often divided between television and "second screens", for example when viewing television broadcasts and following their related social media discussion on a tablet computer. The attentional costs of such multitasking may vary depending on the ebb and flow of the social media channel, such as its emotional contents. In the present study, we tested the hypothesis that negative social media messages would draw more attention than similar positive messages. Specifically, news broadcasts were presented in isolation and with simultaneous positive or negative Twitter messages on a tablet to 38 participants in a controlled experiment. Recognition memory, gaze tracking, cardiac responses, and self-reports were used as attentional indices. The presence of any tweets on the tablet decreased attention to the news broadcasts. As expected, negative tweets drew longer viewing times and elicited more attention to themselves than positive tweets. Negative tweets did not, however, decrease attention to the news broadcasts. Taken together, the present results demonstrate a negativity bias exists for social media messages in media multitasking; however, this effect does not amplify the overall detrimental effects of media multitasking.

  2. Non-depletion floating layer in SOI LDMOS for enhancing breakdown voltage and eliminating back-gate bias effect

    Institute of Scientific and Technical Information of China (English)

    Zheng Zhi; Li Wei; Li Ping

    2013-01-01

    A non-depletion floating layer silicon-on-insulator (NFL SOI) lateral double-diffused metal-oxide-semiconductor (LDMOS) is proposed and the NFL-assisted modulated field (NFLAMF) principle is investigated in this paper.Based on this principle,the floating layer can pin the potential for modulating bulk field.In particular,the accumulated high concentration of holes at the bottom of the NFL can efficiently shield the electric field of the SOI layer and enhance the dielectric field in the buried oxide layer (BOX).At variation of back-gate bias,the shielding charges of NFL can alsoeliminate back-gate effects.The simulated results indicate that the breakdown voltage (BV) is increased from 315 V to 558 V compared to the conventional reduced surface field (RESURF) SOI (CSOI) LDMOS,yielding a 77% improvement.Furthermore,due to the field shielding effect of the NFL,the device can maintain the same breakdown voltage of 558 V with a thinner BOX to resolve the thermal problem in an SOI device.

  3. Effect of meditation on neurophysiological changes in stress mediated depression.

    Science.gov (United States)

    Kasala, Eshvendar Reddy; Bodduluru, Lakshmi Narendra; Maneti, Yogeshwar; Thipparaboina, Rajesh

    2014-02-01

    Meditation is a complex mental practice involving changes in sensory perception, cognition, hormonal and autonomic activity. It is widely used in psychological and medical practices for stress management as well as stress mediated mental disorders like depression. A growing body of literature has shown that meditation has profound effects on numerous physiological systems that are involved in the pathophysiology of major depressive disorder (MDD). Although meditation-based interventions have been associated with improvement in depressive symptoms and prevention of relapse, the physiological mechanisms underlying the therapeutic effects of meditation are not clearly defined and even paradoxical. This paper reviews many of the physiological abnormalities found in cytokine & stress mediated depression and the reversal of these anomalies by different meditation techniques.

  4. The effect of oxidative stress during exercise in the horse.

    Science.gov (United States)

    Williams, C A

    2016-10-01

    Oxidative stress is an imbalance of the oxidant-to-antioxidant ratio in the body. Increases in oxidative stress and changes in antioxidant status have been shown during endurance and intense exercise and eventing competition in horses. Antioxidants include vitamins, minerals, enzymes, and proteins that must be synthesized in the body or obtained from the diet. Therefore, exercise level and diet are both factors that play a role in influencing the oxidative stress and antioxidant status of the equine athlete. Along with exercise intensity and duration, diet, age, and training program can also affect oxidative stress in the horse. Several studies using exogenous supplementation of vitamin E, vitamin C, and alpha-lipoic acid have shown positive results in decreasing the effects of exercise (endurance and intense exercise)-induced oxidative stress and increasing the antioxidant status based on the markers and antioxidants measured, whereas other studies using superoxide dismutase showed little effects on the exercise horse. The "free radical theory of aging" states that long-term effects of the degenerative changes associated with aging may induce oxidative stress. However, in old horses (22 ± 2 yr), lipid peroxidation levels and blood antioxidant concentrations were similar to those found in younger but mature (12 ± 2 yr) horses both at rest and during exercise. Other studies found that yearlings (18 ± 2.4 mo) that are novel to forced exercise had less lipid peroxidation and greater antioxidant status than mature mares (13 ± 2.1 yr) prior to exercise training. Exercise training reduced oxidative stress markers and improved antioxidant status in mares, whereas few effects were seen in yearlings. This indicates that youth provided more defense against oxidative stress due to exercise than the exercise training program. Other studies during competition (endurance, jumping, eventing, and racing) have investigated the influence on oxidative stress with varying results

  5. The role of the (111) texture on the exchange bias and interlayer coupling effects observed in sputtered NiFe/IrMn/Co trilayers

    Energy Technology Data Exchange (ETDEWEB)

    Castro, I. L.; Nascimento, V. P.; Passamani, E. C.; Takeuchi, A. Y.; Larica, C. [Universidade Federal do Espirito Santo, Vitoria, ES 29075-910 (Brazil); Tafur, M. [Universidade Federal de Itajuba, Campus Itabira, Itabira, MG 37500-903 (Brazil); Pelegrini, F. [Universidade Federal de Goias, Goiania, GO 74001-970 (Brazil)

    2013-05-28

    Magnetic properties of sputtered NiFe/IrMn/Co trilayers grown on different seed layers (Cu or Ta) deposited on Si (100) substrates were investigated by magnetometry and ferromagnetic resonance measurements. Exchange bias effect and magnetic spring behavior have been studied by changing the IrMn thickness. As shown by X-ray diffraction, Ta and Cu seed layers provoke different degrees of (111) fcc-texture that directly affect the exchange bias and indirectly modify the exchange spring coupling behavior. Increasing the IrMn thickness, it was observed that the coupling angle between the Co and NiFe ferromagnetic layers increases for the Cu seed system, but it reduces for the Ta case. The results were explained considering (i) different anisotropies of the Co and IrMn layers induced by the different degree of the (111) texture and (ii) the distinct exchange bias set at the NiFe/IrMn and IrMn/Co interfaces in both systems. The NiFe and Co interlayer coupling angle is strongly correlated with both exchange bias and exchange magnetic spring phenomena. It was also shown that the highest exchange bias field occurs when an unstressed L1{sub 2} IrMn structure is stabilized.

  6. Effect of electrode biasing on m/n  =  2/1 tearing modes in J-TEXT experiments

    Science.gov (United States)

    Liu, Hai; Hu, Qiming; Chen, Zhipeng; Yu, Q.; Zhu, Lizhi; Cheng, Zhifeng; Zhuang, Ge; Chen, Zhongyong

    2017-01-01

    The effects of electrode biasing (EB) on the m/n  =  2/1 tearing mode have been experimentally studied in J-TEXT tokamak discharges, where m and n are the poloidal and toroidal mode numbers. It is found that for a negative bias voltage, the mode amplitude is reduced, and the mode frequency is increased accompanied by the increased toroidal plasma rotation speed in the counter-I p direction. For a positive bias voltage, the mode frequency is decreased together with the change of the rotation velocity towards the co-I p direction, and the mode amplitude is increased. Statistic results show that the variations in the toroidal rotation speed, the 2/1 mode frequency and its amplitude linearly depend on the bias voltage. The threshold voltages for complete suppression and locking of the mode are found. The experimental results suggest that applied electrode biasing is a possible method for the avoidance of mode locking and disruption.

  7. Effects of aging on hemispheric asymmetry in inferior frontal cortex activity during belief-bias syllogistic reasoning: a near-infrared spectroscopy study.

    Science.gov (United States)

    Tsujii, Takeo; Okada, Mitsuhiro; Watanabe, Shigeru

    2010-07-11

    The belief-bias effect in syllogistic reasoning refers to the tendency for subjects to be erroneously biased when logical conclusions are incongruent with beliefs about the world. This study examined age-related differences in inferior frontal cortex (IFC) activity associated with belief-bias reasoning using near-infrared spectroscopy (NIRS). The subjects were 32 older (mean age, 68.53 years) and 32 young adult volunteers (mean age, 21.50 years). They performed belief-congruent and incongruent reasoning trials while right and left IFC activities were being measured by NIRS. Behavioral analysis found that older adults exhibited a larger belief-bias than young adults. NIRS analysis showed that the right IFC was more activated than the left IFC in young adults, while there was no significant hemispheric difference in older adults. On correlation analysis, there was a significant positive correlation between reasoning accuracy and IFC activation in both hemispheres for older adults, while in young adults, the correlation was significant only in the right hemisphere. These correlation patterns suggest that the right IFC is critical for resolving conflicting reasoning in young adults, but that older adults may further recruit the left IFC to compensate for the age-related decline in the inhibitory control functions. Thus, we demonstrate, for the first time, age-related differences in neural activity associated with belief-bias reasoning.

  8. Culturally Biased Assumptions in Counseling Psychology

    Science.gov (United States)

    Pedersen, Paul B.

    2003-01-01

    Eight clusters of culturally biased assumptions are identified for further discussion from Leong and Ponterotto's (2003) article. The presence of cultural bias demonstrates that cultural bias is so robust and pervasive that is permeates the profession of counseling psychology, even including those articles that effectively attack cultural bias…

  9. Effects of hemin and thermal stress exposure on JWA expression

    Institute of Scientific and Technical Information of China (English)

    ZHAO Ming; CHEN Rui; LI Aiping; ZHOU Jianwei

    2007-01-01

    To investigate the expression of JWA after hemin and (or) thermal stress exposure,we treated K562 (chronic myelogenous leukemia cells) cells with different doses of hemin and thermal stress using different exposure times.The expression of JWA protein was determined by Western blot analysis.Reverse transcription-polymerase chain reaction was carried out to determine JWA mRNA expression.JWA promoter transcription activity analysis was performed by chloramphenicol acetyl transferase-enzyme linked immunosorbent assay (CAT-ELISA).The expression of JWA protein was significantly increased by up to (3.23 +0.57) folds compared to the control in K562 cells after hemin treatment (50 μM for one week),and a similar pattern was observed in the cells after treatment with thermal stress (42℃) for 2 hours [increased by (8.00+ 1.73) folds].The expression of JWA mRNA was also significantly elevated by up to (1.37 + 0.06)folds in K562 cells treated with hemin (30 μM for 48 hours),and a similar regulatory pattern [increased by (1.87±0.13)folds] was observed with thermal stress exposure (42℃) for 30 minutes.However,a combined antagonistic effect was observed in the treatment of K562 cells with hemin (30 μM,48 h) followed by thermal stress (42℃,30 min).CAT-ELISA further confirmed that either hemin or thermal stress treatment could up-regulate JWA transcription activity,however,the effects could be counteracted partly by treatment with a combination of both.Hemin and thermal stress might regulate JWA expression via distinct intracellular signal transduction pathways.

  10. Re-conceptualizing stress: Shifting views on the consequences of stress and its effects on stress reactivity

    Science.gov (United States)

    Liu, Jenny J. W.

    2017-01-01

    Background The consequences of stress are typically regarded from a deficit-oriented approach, conceptualizing stress to be entirely negative in its outcomes. This approach is unbalanced, and may further hinder individuals from engaging in adaptive coping. In the current study, we explored whether negative views and beliefs regarding stress interacted with a stress framing manipulation (positive, neutral and negative) on measures of stress reactivity for both psychosocial and physiological stressors. Method Ninety participants were randomized into one of three framing conditions that conceptualized the experience of stress in balanced, unbalanced-negative or unbalanced-positive ways. After watching a video on stress, participants underwent a psychosocial (Trier Social Stress Test), or a physiological (CO2 challenge) method of stress-induction. Subjective and objective markers of stress were assessed. Results Most of the sampled population regarded stress as negative prior to framing. Further, subjective and objective reactivity were greater to the TSST compared to the CO2 challenge. Additionally, significant cubic trends were observed in the interactions of stress framing and stress-induction methodologies on heart rate and blood pressure. Balanced framing conditions in the TSST group had a significantly larger decrease in heart rate and diastolic blood pressure following stress compared to the positive and negative framing conditions. Conclusion Findings confirmed a deficit-orientation of stress within the sampled population. In addition, results highlighted the relative efficacy of the TSST compared to CO2 as a method of stress provocation. Finally, individuals in framing conditions that posited stress outcomes in unbalanced manners responded to stressors less efficiently. This suggests that unbalanced framing of stress may have set forth unrealistic expectations regarding stress that later hindered individuals from adaptive responses to stress. Potential

  11. Effect of Upper-Cycle Temperature on the Load-Biased, Strain-Temperature Response of NiTi

    Science.gov (United States)

    Padula, Santo; Qiu, Shipeng; Gaydosh, Darrell; Noebe, Ronald; Bigelow, Glen; Garg, Anita; Vaidyanathan, Raj

    2012-12-01

    Over the past decade, interest in shape-memory-alloy based actuators has increased as the primary benefits of these solid-state devices have become more apparent. However, much is still unknown about the characteristic behavior of these materials when used in actuator applications. Recently, we showed that the maximum temperature reached during thermal cycling under isobaric conditions could significantly affect the observed mechanical response of NiTi (55 wt pct Ni), especially the amount of transformation strain available for actuation and thus work output. The investigation we report here extends that original work to (1) ascertain whether increases in the upper-cycle temperature would produce additional changes in the work output of the material, which has a stress-free austenite finish temperature of 386 K (113 °C), and (2) determine the optimum cyclic conditions. Thus, isobaric, thermal-cycle experiments were conducted on the aforementioned alloy at various stresses from 50 to 300 MPa using upper-cycle temperatures of 438 K, 473 K, 503 K, 533 K, 563 K, 593 K, and 623 K (165 °C, 200 °C, 230 °C, 260 °C, 290 °C, 320 °C, and 350 °C). The data indicated that the amount of applied stress influenced the transformation strain, as would be expected. However, the maximum temperature reached during the thermal excursion also plays an equally significant role in determining the transformation strain, with the maximum transformation strain observed during thermal cycling to 563 K (290 °C). In situ neutron diffraction at stress and temperature showed that the differences in transformation strain were mostly related to changes in martensite texture when cycling to different upper-cycle temperatures. Hence, understanding this effect is important to optimizing the operation of SMA-based actuators and could lead to new methods for processing and training shape-memory alloys for optimal performance.

  12. Site Measurement of Surrounding Rock Pressure and Analysis of Structure Stress of Large-span Bias-pressured Shallow Tunnels%大跨浅埋偏压隧道围压实测及结构受力分析

    Institute of Scientific and Technical Information of China (English)

    江磊; 侯哲生; 吴海卫

    2015-01-01

    大跨浅埋偏压隧道由于其非对称的受力条件,易引发结构变形与开裂等突出问题,近年来越来越受工程技术界的重视。以邢汾高速公路邢台段后偏梁大跨度隧道浅埋偏压段为例,通过实测围岩压力,根据荷载结构法的基本原理,利用 ANSYS 软件对其结构受力特性进行数值分析,得到结论:实测的围岩压力分布和偏压的地形之间具有较为一致的对应性,即围岩压力受地形的影响显著;二衬总应力受轴力引起的应力影响较小,主要受弯矩引起的应力控制,整个拱圈范围内最危险的部位是在受围岩压力最大的左侧拱肩处;随着二衬厚度的变化,二衬总应力在不同的部位均发生相应变化,但变化幅度均不大。相关研究结论为后续类似大跨浅埋偏压隧道的合理设计与施工提供参考依据。%The asymmetrical stress condition of the Large-span bias-pressured shallow tunnels can cause many problems easily ,such as structural deformation and cracking .These problems have attracted more and more attentions from engi-neering and technology research field in recent years .The Houpianliang large-span bias-pressured shallow tunnel in Xing-tai section of Xingtai - Fenyang highway was taken as an example to numerically analyze the mechanical characteristics of the structure by adopting ANSYS ,according to the data of site measurement of surrounding rock pressure and the princi -ple of load structure method .The results indicate that :the actual measured surrounding rock pressure is consistent with the bias terrain ,which means the surrounding rock pressure is influenced by topography significantly ;the total stress of the second lining is mainly controlled by the stress from bending moment and is less influenced by the stress from axial force ,the weakest part within the scope of the arch ring is the left spandrel which is subject to maximum pressure ;with the change of the

  13. CALIPSO-inferred aerosol direct radiative effects: Bias estimates using ground-based Raman lidars

    Science.gov (United States)

    Thorsen, Tyler J.; Fu, Qiang

    2015-12-01

    Observational constraints on the change in the radiative energy budget caused by the presence of aerosols, i.e., the aerosol direct radiative effect (DRE), have recently been made using observations from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite (CALIPSO). CALIPSO observations have the potential to provide improved global estimates of aerosol DRE compared to passive sensor-derived estimates due to CALIPSO's ability to perform vertically resolved aerosol retrievals over all surface types and over cloud. In this study, uncertainties in CALIPSO-inferred aerosol DRE are estimated using multiple years of observations from the Atmospheric Radiation Measurement (ARM) program's Raman lidars at midlatitude and tropical sites. We find that CALIPSO is unable to detect all radiatively significant aerosol, resulting in an underestimate in the magnitude of the aerosol DRE by 30-50% at the two ARM sites. The undetected aerosol is likely the consequence of random noise in CALIPSO measurements and therefore will affect global observations as well. This suggests that the global aerosol DRE inferred from CALIPSO observations are likely too weak. Also examined is the impact of the ratio of extinction-to-backscatter (i.e., the lidar ratio) whose value CALIPSO retrievals must assume to obtain the aerosol extinction profile. It is shown that if CALIPSO can reproduce the climatological value of the lidar ratio at a given location, then the aerosol DRE there can be accurately calculated (within about 3%).

  14. Exchange bias effect and glassy-like behavior of EuCrO3 and CeCrO3 nano-powders

    Science.gov (United States)

    Taheri, M.; Kremer, R. K.; Trudel, S.; Razavi, F. S.

    2015-09-01

    The magnetic properties of nano-sized EuCrO3 and CeCrO3 powders, synthesized by a solution combustion method, were investigated using DC/AC magnetization measurements. An exchange bias effect, magnetization irreversibility and AC susceptibility dispersion in these samples provided evidence for the presence of the spin disorder magnetic phase. The exchange bias phenomenon, which is assigned to the exchange coupling between the glassy-like shell and canted antiferromagnetic core, showed the opposite sign in EuCrO3 and CeCrO3 at low temperatures, suggesting different exchange interactions at the interfaces in these compounds. We also observed a sign reversal of exchange bias in CeCrO3 at different temperatures.

  15. Exchange bias effect and glassy-like behavior of EuCrO{sub 3} and CeCrO{sub 3} nano-powders

    Energy Technology Data Exchange (ETDEWEB)

    Taheri, M., E-mail: maryam.taheri@brocku.ca; Razavi, F. S. [Department of Physics, Brock University, St. Catharines, Ontario L2S 3A1 (Canada); Kremer, R. K. [Department of Physics, Brock University, St. Catharines, Ontario L2S 3A1 (Canada); Max Planck Institute for Solid State Research, D-70569 Stuttgart (Germany); Trudel, S. [Department of Chemistry, University of Calgary, Calgary, Alberta T2N 1N4 (Canada)

    2015-09-28

    The magnetic properties of nano-sized EuCrO{sub 3} and CeCrO{sub 3} powders, synthesized by a solution combustion method, were investigated using DC/AC magnetization measurements. An exchange bias effect, magnetization irreversibility and AC susceptibility dispersion in these samples provided evidence for the presence of the spin disorder magnetic phase. The exchange bias phenomenon, which is assigned to the exchange coupling between the glassy-like shell and canted antiferromagnetic core, showed the opposite sign in EuCrO{sub 3} and CeCrO{sub 3} at low temperatures, suggesting different exchange interactions at the interfaces in these compounds. We also observed a sign reversal of exchange bias in CeCrO{sub 3} at different temperatures.

  16. On the relative independence of thinking biases and cognitive ability.

    Science.gov (United States)

    Stanovich, Keith E; West, Richard F

    2008-04-01

    In 7 different studies, the authors observed that a large number of thinking biases are uncorrelated with cognitive ability. These thinking biases include some of the most classic and well-studied biases in the heuristics and biases literature, including the conjunction effect, framing effects, anchoring effects, outcome bias, base-rate neglect, "less is more" effects, affect biases, omission bias, myside bias, sunk-cost effect, and certainty effects that violate the axioms of expected utility theory. In a further experiment, the authors nonetheless showed that cognitive ability does correlate with the tendency to avoid some rational thinking biases, specifically the tendency to display denominator neglect, probability matching rather than maximizing, belief bias, and matching bias on the 4-card selection task. The authors present a framework for predicting when cognitive ability will and will not correlate with a rational thinking tendency.

  17. Effect of mechanical strain on magnetic properties of flexible exchange biased FeGa/IrMn heterostructures

    Science.gov (United States)

    Zhang, Xiaoshan; Zhan, Qingfeng; Dai, Guohong; Liu, Yiwei; Zuo, Zhenghu; Yang, Huali; Chen, Bin; Li, Run-Wei

    2013-01-01

    We have fabricated flexible exchange biased heterostructures with magnetostrictive Fe81Ga19 alloy as the ferromagnetic layer and Ir20Mn80 as the antiferromagnetic layer on polyethylene terephthalate substrates. The mechanical strain can modify both the strength and the orientation of the uniaxial anisotropy, giving rise to the switching between the easy and hard magnetization directions. Different from the previously reported works on rigid exchange biased systems, a drastic decrease in exchange bias field was observed under a compressive strain with magnetic field parallel to the pinning direction, but only a slightly decrease was shown under a tensile strain. Based on a Stoner-Wohlfarth model calculation, we suggested that the distributions of both ferromagnetic and antiferromagnetic anisotropies be the key to induce the mechanically tunable exchange bias.

  18. Experimental and Theoretical Study of 4H-SiC JFET Threshold Voltage Body Bias Effect from 25 C to 500 C

    Science.gov (United States)

    Neudeck, Philip G.; Spry, David J.; Chen, Liangyu

    2015-01-01

    This work reports a theoretical and experimental study of 4H-SiC JFET threshold voltage as a function of substrate body bias, device position on the wafer, and temperature from 25 C (298K) to 500 C (773K). Based on these results, an alternative approach to SPICE circuit simulation of body effect for SiC JFETs is proposed.

  19. Impact of bias discrepancy and amino acid usage on estimates of the effective number of codons used in a gene, and a test for selection on codon usage

    DEFF Research Database (Denmark)

    Fuglsang, Anders

    2007-01-01

    The effective number of codons (Nc) used in a gene is one of the most commonly used measures of synonymous codon usage bias, owing much of its popularity to the fact that it is species independent and that simulation studies have shown that it is less dependent of gene length than other measures....... that exists for Buchnera sp. APS and Borrelia burgdorferi....

  20. Effect of intermediate principal stress on strength of soft rock under complex stress states

    Institute of Scientific and Technical Information of China (English)

    马宗源; 廖红建; 党发宁

    2014-01-01

    A series of numerical simulations of conventional and true triaxial tests for soft rock materials using the three-dimensional finite difference code FLAC3D were presented. A hexahedral element and a strain hardening/softening constitutive model based on the unified strength theory (UST) were used to simulate both the consolidated-undrained (CU) triaxial and the consolidated-drained (CD) true triaxial tests. Based on the results of the true triaxial tests simulation, the effect of the intermediate principal stress on the strength of soft rock was investigated. Finally, an example of an axial compression test for a hard rock pillar with a soft rock interlayer was analyzed using the two-dimensional finite difference code FLAC. The CD true triaxial test simulations for diatomaceous soft rock suggest the peak and residual strengths increase by 30%when the effect of the intermediate principal stress is taken into account. The axial compression for a rock pillar indicated the peak and residual strengths increase six-fold when the soft rock interlayer approached the vertical and the effect of the intermediate principal stress is taken into account.

  1. Problem solving moderates the effects of life event stress and chronic stress on suicidal behaviors in adolescence.

    Science.gov (United States)

    Grover, Kelly E; Green, Kelly L; Pettit, Jeremy W; Monteith, Lindsey L; Garza, Monica J; Venta, Amanda

    2009-12-01

    The present study examined the unique and interactive effects of stress and problem-solving skills on suicidal behaviors among 102 inpatient adolescents. As expected, life event stress and chronic stress each significantly predicted suicidal ideation and suicide attempt. Problem solving significantly predicted suicidal ideation, but not suicide attempt. Problem solving moderated the associations between life event stress and suicidal behaviors, as well as between chronic stress and suicidal ideation, but not chronic stress and suicide attempt. At high levels of stress, adolescents with poor problem-solving skills experienced elevated suicidal ideation and were at greater risk of making a nonfatal suicide attempt. The interactive effects decreased to non-significance after controlling for depressive symptoms and hopelessness. Clinical implications are discussed.

  2. Better executive function under stress mitigates the effects of recent life stress exposure on health in young adults.

    Science.gov (United States)

    Shields, Grant S; Moons, Wesley G; Slavich, George M

    2017-01-01

    Executive function is a neuropsychological construct that enables controlled cognitive processing, which has been hypothesized to enhance individuals' resilience to stress. However, little empirical work has directly examined how executive function under different conditions mitigates the negative effects of stress exposure on health. To address this issue, we recruited 110 healthy young adults and assessed their recent life stress exposure, executive function in either a stressful or non-stressful context, and current health complaints. Based on existing research, we hypothesized that individuals exhibiting better executive function following a laboratory-based stressor (but not a control task) would demonstrate weaker associations between recent stress exposure and health because they perceived recent life stressors as being less severe. Consistent with this hypothesis, better executive function during acute stress, but not in the absence of stress, was associated with an attenuated link between participants' recent life stress exposure and their current health complaints. Moreover, this attenuating effect was mediated by lesser perceptions of stressor severity. Based on these data, we conclude that better executive function under stress is associated with fewer health complaints and that these effects may occur by reducing individuals' perceptions of stressor severity. The data thus suggest the possibility of reducing stress-related health problems by enhancing executive function.

  3. Alpha 2B adrenoceptor genotype moderates effect of reboxetine on negative emotional memory bias in healthy volunteers.

    Science.gov (United States)

    Gibbs, Ayana A; Bautista, Carla E; Mowlem, Florence D; Naudts, Kris H; Duka, Theodora

    2013-10-23

    Evidence suggests that emotional memory plays a role in the pathophysiology of depression/anxiety disorders. Noradrenaline crucially modulates emotional memory. Genetic variants involved in noradrenergic signaling contribute to individual differences in emotional memory and vulnerability to psychopathology. A functional deletion polymorphism in the α-2B adrenoceptor gene (ADRA2B) has been linked to emotional memory and post-traumatic stress disorder. The noradrenaline reuptake inhibitor reboxetine attenuates enhanced memory for negative stimuli in healthy and depressed individuals. We examined whether the effect of reboxetine on emotional memory in healthy individuals would be moderated by ADRA2B genotype. ADRA2B deletion carriers demonstrated enhanced emotional memory for negative stimuli compared with deletion noncarriers, consistent with prior studies. Reboxetine attenuated enhanced memory for negative stimuli in deletion noncarriers but had no significant effect in deletion carriers. This is the first demonstration of genetic variation influencing antidepressant drug effects on emotional processing in healthy humans.

  4. Stress and its effects on horses reproduction

    Directory of Open Access Journals (Sweden)

    Amal M. AboEl-Maaty

    2011-11-01

    Full Text Available A total of 90 mares and horses were subjected to blood sampling for determining the effect of management (farm, reproductive condition, sex, age, breed and month of the year during breeding on circulating levels of cortisol and sex hormones. Blood samples were collected from December to the following June from four farms. Blood sera underwent testosterone, estradiol, progesterone and cortisol assaying using ELISA kits. Cortisol levels were significantly low in lactating mares during their foal heat but significantly high levels were recorded in both repeat breeder mares and horses used for racing. High and significant testosterone and estradiol levels were recorded in both stallions used for breeding especially after semen collection and early pregnant mares. Similar testosterone levels were recorded in both early pregnant mares and racing horses but high levels were recorded in stallions. Estradiol was high in both early pregnant and mares with endometritis but the highest levels were observed in stallions. Horses held in private farms had high cortisol levels compared to those of governmental farms. In contrast to mares, horses had low cortisol and high estradiol levels. Cortisol levels were high from April to June (Spring and early summer compared to its levels from December to March (Winter. Arab horses had low cortisol compared to native and imported foreign breeds. In conclusion, environmental condition, exercise, breed, management and the purpose of raising horses all are affecting its cortisol levels.

  5. Awareness Reduces Racial Bias

    OpenAIRE

    2014-01-01

    Can raising awareness of racial bias subsequently reduce that bias? We address this question by exploiting the widespread media attention highlighting racial bias among professional basketball referees that occurred in May 2007 following the release of an academic study. Using new data, we confirm that racial bias persisted in the years after the study's original sample, but prior to the media coverage. Subsequent to the media coverage though, the bias completely disappeared. We examine poten...

  6. Stress in Irish dentists: developing effective coping strategies.

    LENUS (Irish Health Repository)

    Rogers, Cathryn

    2012-02-01

    Recent research has highlighted the need to recognise occupation-specific risk factors contributing to stress and burnout. As health professionals, it is important for dentists to recognise the symptoms and the effects of stress on physical, psychological and professional well being. This article reviews the relevant scientific evidence, and provides practical cognitive psychological measures to guide improved well-being for dentists. Any stigma-related factors need to be acknowledged and addressed for the wellbeing of dentists and their patients, and the dental profession is well placed to provide leadership on this issue. Peer support is central to meeting this challenge.

  7. Brief communication: Effect of size biases in the coefficient of variation on assessing intraspecific variability in the prosimian skeleton.

    Science.gov (United States)

    Fulwood, Ethan L; Kramer, Andrew

    2013-09-01

    This study examines the effect of a measurement size bias in coefficients of variation on the evaluation of intraspecific skeletal variability in a sample of eight prosimian species (Eulemur fulvus, Hapalemur griseus, Lemur catta, Varecia variegata, Galago senegalensis, Otolemur crassicaudatus, Nycticebus coucang, and Tarsius syrichta). Measurements with smaller means were expected to have higher coefficients of variation (CVs) due to the impact of instrumental precision on the ability to assess variability. This was evaluated by testing for a negative correlation between CVs and means in the total sample, within each species, and within each measurement, and by testing for the leveraging impact of small measurements on the significance of comparisons of variability between regions of the prosimian skeleton. Three comparisons were made: cranial versus postcranial variability, epiphysis versus diaphysis variability, and forelimb versus hindlimb variability. CVs were significantly negatively correlated with means within the total sample (r(2) = 0.208, P < 0.0001) and within each species. CVs and means were significantly correlated within only three of the measurements, which may reflect the relatively low body size range of the species studied. As predicted by the higher variability of smaller measurements, removing the smallest measurements from comparisons of variable classes containing measurements of different mean magnitudes pushed the comparisons below significance. These results indicate caution should be exercised when using CVs to assess variability across sets of measurements with different means.

  8. [Effects of organic manure on wheat growth under lead stress].

    Science.gov (United States)

    Qiao, Sha-sha; Zhang, Yong-qing; Yang, Li-wen; Pei, Hong-bin; Sun, Hong-shuai

    2011-04-01

    A pot experiment was conducted to study the effects of organic manure on the wheat growth under different levels of lead stress. With increasing lead stress level, whether fertilization or not, the plant height, shoot dry mass, adventitious root number, root total length, root dry mass, root activity, root total and active absorbing area, and root SOD and POD activities decreased, and root MDA content presented an increasing trend. The decrement of the above-mentioned parameters differed with fertilization treatments. Applying organic manure mitigated the impact of lead stress on wheat growth to some extent, delayed the senescence of wheat roots, and promoted root development and growth, ultimately leading to the increase of wheat yield and the decrease of lead content in grain.

  9. The effect of acute and chronic stress on growth.

    Science.gov (United States)

    Sävendahl, Lars

    2012-10-23

    Impaired bone growth is observed in many children exposed to stress, but whether the underlying cause is psychological or secondary to a variety of chronic disorders is unclear. The growth plate is specifically targeted by stress through many different mechanisms, including increased serum concentrations of proinflammatory cytokines and cortisol, as well as impaired actions of the growth hormone (GH)-insulin-like growth factor-1 (IGF-1) axis. Both glucocorticoids, such as cortisol, and proinflammatory cytokines adversely affect several aspects of chondrogenesis in the growth plate, and these effects can be ameliorated by raising local IGF-1 concentrations. However, this intervention does not completely normalize growth. In children with stress related to chronic inflammation, the cornerstone of improving stress-impaired growth remains the judicious use of glucocorticoids while ensuring effective control of the disease process. Specific immunomodulatory therapy that targets the actions of tumor necrosis factor-α (TNFα) is at least partially effective at rescuing linear growth in many children with juvenile idiopathic arthritis (JIA). Patients who do not respond to anti-TNF treatment may be candidates for therapeutic agents that target other proinflammatory cytokines and for GH intervention. Although GH treatment rescues linear growth in some patients with JIA, it is unknown whether GH can rescue growth in those patients who do not respond to anticytokine therapy. Further experimental and clinical studies are needed to explore these and other new potential treatment strategies that could improve bone growth in patients who do not respond to conventional therapy.

  10. The Effect of Oxidative Stress and Antioxidants on Men Fertility

    Directory of Open Access Journals (Sweden)

    Abolfazl Akbari

    2013-07-01

    Full Text Available Background: Various factors affects men fertility and oxidative stress as an important factor which affects fertility has recently got great concern. Oxidative stress refers to conditions of imbalance between productions of reactive oxygen species (ROS and antioxidant defense mechanism. Reactive species of oxygen, free radicals and peroxide are produced in the cell when metabolism of oxygen is incomplete in the mitochondrial respiratory chain.Materials and Methods: In this review we will consider effect of oxidative stress on male fertility and the principal antioxidant defences.Results: Factors such as hypoxia, cytokines, growth factors, chemotherapy, radio frequency waves and UV radiation can increase ROS production. Oxidative stress as one of the strongest physiological factors can lead to damage of sperm and reduction of seminal plasma quality and thereby cause infertility in men. Enzymatic and non-enzymatic defences inhibit oxidant attack. The enzymatic defense include: superoxide dismutases, glutathione peroxidases, and catalase. The non-enzymatic defences include ascorbate (vitamin C and a-tocopherol (vitamin E, beta carotene, and albumin, which neutralize free radicals. Conclusion: Oxidative stress affects male fertility through induction of lipid peroxidation, inactivation of proteins, impair of sperm motility and DNA damage.

  11. Investigating The Effect Of Job Stress On Performance Of Employees

    Directory of Open Access Journals (Sweden)

    Oyungerel Altangerel

    2015-02-01

    Full Text Available Abstract This study is conducted to investigate the effect of job stress on job performance. A random sampling technique is used to collect primary data of 120 employees of four telecommunication companies of Mongolia i.e. Mobicom Unitel Skytel and G-mobile. A well-structured questionnaire is utilized to collect relevant data descriptive and logistic analysis is used to estimate and describe the findings of results. It is found that work overload is major reason of stress among employees and majority of employees reduce their productivity and loss of interest in job due to stress. As for concern health issue eyes strain dizziness and disorder in sleep are due to job stress. According to results of logit model parameters of education experience and salary per month are statistically significant and have positive impact on employees performance but age family size no relaxation time giving to employees during working hours and work overload are statistically significant and have negative impact on employees job performance. For suggestions companies should increase salaries of employees and give reward to employees those have work overload. Workload of employees should reduce by proper work redesign and efficient management by proper allocation of job. It is also found that stress also becomes reason of several illnesses and majority of employees dont have medical facilities first aid at working place therefore it is suggested that companies should also provide medical facilities first aid for employees at work place.

  12. Effect of Kegel Exercises on the Management of Female Stress Urinary Incontinence: A Systematic Review of Randomized Controlled Trials

    Directory of Open Access Journals (Sweden)

    Seong-Hi Park

    2014-01-01

    Full Text Available Objective. The purpose of this study was to evaluate the effect of Kegel exercises on reducing urinary incontinence symptoms in women with stress urinary incontinence. Methods. Randomized controlled trials (RCTs were conducted on females with stress urinary incontinence who had done Kegel exercises and met inclusion criteria in articles published between 1966 and 2012. The articles from periodicals indexed in KoreaMed, NDSL, Ovid Medline, Embase, Scopus, and other databases were selected, using key terms such as “Kegel” or “pelvic floor exercise.” Cochrane’s risk of bias was applied to assess the internal validity of the RCTs. Eleven selected studies were analyzed by meta-analysis using RevMan 5.1. Results. Eleven trials involving 510 women met the inclusion criteria. All trials contributed data to one or more of the main or secondary outcomes. They indicated that Kegel exercises significantly reduced the urinary incontinence symptoms of female stress urinary incontinence. There was no heterogeneity in the selected studies except the standardized bladder volumes of the pad test. Conclusion. There is some evidence that, for women with stress urinary incontinence, Kegel exercises may help manage urinary incontinence. However, while these results are helpful for understanding how to treat or cure stress urinary incontinence, further research is still required.

  13. The Effect of Residual Stress on the Wear Properties of Dlc Coatings

    Science.gov (United States)

    Jang, Young-Jun; Kim, Seock-Sam; Rha, Jong-Joo

    Multi-layer diamond-like carbon (DLC) coating, 150 and 220 nm thick were deposited by negative pulsed d.c. bias induced with magnetron sputtering. The objective of this research is to resolve a wear resistance in terms of DLC coating residual stress and mechanical properties. The bias was controlled from - 200 to 0 V during 10 second with point contacting controller. The surface structure was continuously fabricating to soft and hard-layer during deposition. It was shown that the compressive residual stress and hardness were 0.09, 18 GPa under multi-layer coating condition. The as-deposited DLC coating has a relatively higher wear resistance than unmodified DLC under nanoabrasive wear. It also showed that multi-layer DLC coating had no wear until 400 nN. The decreased residual stress and increased film hardness in the multi-layer coating gave a rise to increase wear resistance.

  14. CROSS-EFFECTS OF ADAPTATION TO STRESS SITUATIONS

    Directory of Open Access Journals (Sweden)

    Alexey Viktorovich MESHCHERYAKOV

    2015-01-01

    Full Text Available To counteract the stress it is necessary to study its effect on the internal condition of the body. The level of achievements in various sports and employments is determined by the exhaust motor programs that are improved in the process of trainings, ensuring the achievement of high results and reducing the mental and energy losses. Adaptation to short-term impacts of the stressor naturally leads to increased physiological capacity of the sympathetic-adrenal regulation. The recruitment of this regulatory system is an essential and absolute link of adaptation to the effects of environmental factors. It can be affirmed that adaptation to extreme situations increases the resistance not only to separate factors but to all factors affecting the body. Thus, adaptation has a positive cross-effect. We believe it is important to assess the possible impacts of the elaborated methodology on the development of the vestibular apparatus that includes cross-effects of adaptation to stress situations on the readiness of athletes. The article presents conclusions about the possibilities to improve the coordination abilities of athletes through targeted effect on their special preparedness by the original methods which intensify the effects of adaptation to stress situations. The changes were assessed based on the data obtained using a stabilometric platform. 

  15. Stress

    DEFF Research Database (Denmark)

    Keller, Hanne Dauer

    2015-01-01

    Kapitlet handler om stress som følelse, og det trækker primært på de få kvalitative undersøgelser, der er lavet af stressforløb.......Kapitlet handler om stress som følelse, og det trækker primært på de få kvalitative undersøgelser, der er lavet af stressforløb....

  16. Temperature trend biases

    Science.gov (United States)

    Venema, Victor; Lindau, Ralf

    2016-04-01

    In an accompanying talk we show that well-homogenized national dataset warm more than temperatures from global collections averaged over the region of common coverage. In this poster we want to present auxiliary work about possible biases in the raw observations and on how well relative statistical homogenization can remove trend biases. There are several possible causes of cooling biases, which have not been studied much. Siting could be an important factor. Urban stations tend to move away from the centre to better locations. Many stations started inside of urban areas and are nowadays more outside. Even for villages the temperature difference between the centre and edge can be 0.5°C. When a city station moves to an airport, which often happened around WWII, this takes the station (largely) out of the urban heat island. During the 20th century the Stevenson screen was established as the dominant thermometer screen. This screen protected the thermometer much better against radiation than earlier designs. Deficits of earlier measurement methods have artificially warmed the temperatures in the 19th century. Newer studies suggest we may have underestimated the size of this bias. Currently we are in a transition to Automatic Weather Stations. The net global effect of this transition is not clear at this moment. Irrigation on average decreases the 2m-temperature by about 1 degree centigrade. At the same time, irrigation has increased significantly during the last century. People preferentially live in irrigated areas and weather stations serve agriculture. Thus it is possible that there is a higher likelihood that weather stations are erected in irrigated areas than elsewhere. In this case irrigation could lead to a spurious cooling trend. In the Parallel Observations Science Team of the International Surface Temperature Initiative (ISTI-POST) we are studying influence of the introduction of Stevenson screens and Automatic Weather Stations using parallel measurements

  17. Memory function after stress : the effects of acute stress and cortisol on memory and the inhibition of emotional distraction

    NARCIS (Netherlands)

    Oei, Nicole Yü Lan

    2010-01-01

    The present thesis contains five experimental studies into the effects of stress on memory I healthy males. Hydrocortisone (and propranolol) administration or the induction of social stress are used to heighten cortisol levels, and consequently to study its effects on working memory performance and

  18. Amygdala-Hippocampal Connectivity Changes During Acute Psychosocial Stress: Joint Effect of Early Life Stress and Oxytocin.

    Science.gov (United States)

    Fan, Yan; Pestke, Karin; Feeser, Melanie; Aust, Sabine; Pruessner, Jens C; Böker, Heinz; Bajbouj, Malek; Grimm, Simone

    2015-11-01

    Previous evidence shows that acute stress changes both amygdala activity and its connectivity with a distributed brain network. Early life stress (ELS), especially emotional abuse (EA), is associated with altered reactivity to psychosocial stress in adulthood and moderates or even reverses the stress-attenuating effect of oxytocin (OXT). The neural underpinnings of the interaction between ELS and OXT remain unclear, though. Therefore, we here investigate the joint effect of ELS and OXT on transient changes in amygdala-centered functional connectivity induced by acute psychosocial stress, using a double-blind, randomized, placebo-controlled, within-subject crossover design. Psychophysiological interaction analysis in the placebo session revealed stress-induced increases in functional connectivity between amygdala and medial prefrontal cortex, posterior cingulate cortex, putamen, caudate and thalamus. Regression analysis showed that EA was positively associated with stress-induced changes in connectivity between amygdala and hippocampus. Moreover, hierarchical linear regression showed that this positive association between EA and stress-induced amygdala-hippocampal connectivity was moderated after the administration of intranasal OXT. Amygdala-hippocampal connectivity in the OXT session correlated negatively with cortisol stress responses. Our findings suggest that altered amygdala-hippocampal functional connectivity during psychosocial stress may have a crucial role in the altered sensitivity to OXT effects in individuals who have experienced EA in their childhood.

  19. Reducing negative interpretations in adolescents with anxiety disorders: a preliminary study investigating the effects of a single session of cognitive bias modification training.

    Science.gov (United States)

    Fu, Xiaoxue; Du, Yasong; Au, Shun; Lau, Jennifer Y F

    2013-04-01

    Anxiety disorders are globally prevalent, debilitating and onset in early life. Cognitive bias modification of interpretations (CBM-I) training has emerged as a targeted intervention for early emerging anxiety problems. While CBM-I can alter interpretational styles in unselected and clinical-analogue samples of adolescents, no studies have assessed its capacity to change biases in clinical samples. Here, we assessed training efficacy in ameliorating interpretation biases and anxious mood in adolescents with anxiety disorders. Twenty-eight Chinese adolescents meeting criteria for a current anxiety disorder were randomly assigned to receive positive or neutral CBM-I training. Training involved completing a word-fragment to resolve the outcomes of sixty ambiguous scenarios. During positive training, scenarios ended with benign/positive resolutions, but during neutral training, half of the scenarios were resolved positively and half negatively. Positively trained patients interpreted new ambiguous scenarios less negatively than the neutral training group although training effects were not observed on a questionnaire measure of interpretation bias. Training effects on mood were also absent. Before the clinical implications of CBM-I can be considered in adolescents, research needs to establish optimal training parameters for symptom-changes to occur.

  20. [The role of individual stress resistance in realization of immobilization and zoosocial stress effects on pulmonary surfactant system].

    Science.gov (United States)

    Vasil'eva, N N; Bryndina, I G

    2012-07-01

    The aim of the present study was to investigate the effect of chronic exposure to immobilization and psychosocial stress on surface activity, biochemical composition of pulmonary surfactant and lung fluid balance of rats with different stress-resistance. It is shown that both types of stress lead to elevation of lysophospholipids level and decrease of surface-active properties of pulmonary surfactant, more prominent in stress-vulnerable rats. Blood supply was decreased and extravascular fluid was increased under the psychosocial stress only in stress-vulnerable animals, in all rest cases the blood supply was increased and the content of extravascular fluid was not changed. Surfactant alteration was coupled on the level of 11-OCS in the blood and amount of fluid in the lungs. The obtained results indicate that different degree of impairment in the pulmonary surfactant system during immobilization and psychosocial conflicts depends on different resistance to emotional stress.

  1. Macro design effects on stress distribution around implants: A photoelastic stress analysis

    Directory of Open Access Journals (Sweden)

    Serhat Emre Ozkir

    2012-01-01

    Conclusion: As there were observable differences between the implant types, straight placed cylindrical implants showed better stress distribution characteristics, while inclined tapering implants had better stress distribution characteristics.

  2. Effect of applied dc bias voltage on composition, chemical bonding and mechanical properties of carbon nitride films prepared by PECVD

    Institute of Scientific and Technical Information of China (English)

    LI Hong-xuan; XU Tao; HAO Jun-ying; CHEN Jian-min; ZHOU Hui-di; XUE Qun-ji; LIU Hui-wen

    2004-01-01

    Carbon nitride films were deposited on Si (100) substrates using plasma-enhanced chemical vapor deposition (PECVD) technique from CH4 and N2 at different applied dc bias voltage. The microstructure, composition and chemical bonding of the resulting films were characterized by Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The mechanical properties such as hardness and elastic modulus of the films were evaluated using nano-indentation. As the results, the Raman spectra, showing the G and D bands, indicate the amorphous structure of the films. XPS and FTIR measurements demonstrate the existence of various carbon-nitride bonds in the films and the hydrogenation of carbon nitride phase. The composition ratio of N to C, the nano-hardness and the elastic modulus of the carbon nitride films increase with increasing dc bias voltage and reach the maximums at a dc bias voltage of 300 V, then they decrease with further increase of the dc bias voltage. Moreover, the XRD analyses indicate that the carbon nitride film contains some polycrystalline C3N4 phase embedded in the amorphous matrix at optimized deposition condition of dc bias voltage of 300 V.

  3. The effect of stress state on zirconium hydride reorientation

    Science.gov (United States)

    Cinbiz, Mahmut Nedim

    Prior to storage in a dry-cask facility, spent nuclear fuel must undergo a vacuum drying cycle during which the spent fuel rods are heated up to elevated temperatures of ≤ 400°C to remove moisture the canisters within the cask. As temperature increases during heating, some of the hydride particles within the cladding dissolve while the internal gas pressure in fuel rods increases generating multi-axial hoop and axial stresses in the closed-end thin-walled cladding tubes. As cool-down starts, the hydrogen in solid solution precipitates as hydride platelets, and if the multiaxial stresses are sufficiently large, the precipitating hydrides reorient from their initial circumferential orientation to radial orientation. Radial hydrides can severely embrittle the spent nuclear fuel cladding at low temperature in response to hoop stress loading. Because the cladding can experience a range of stress states during the thermo-mechanical treatment induced during vacuum drying, this study has investigated the effect of stress state on the process of hydride reorientation during controlled thermo-mechanical treatments utilizing the combination of in situ X-ray diffraction and novel mechanical testing analyzed by the combination of metallography and finite element analysis. The study used cold worked and stress relieved Zircaloy-4 sheet containing approx. 180 wt. ppm hydrogen as its material basis. The failure behavior of this material containing radial hydrides was also studied over a range of temperatures. Finally, samples from reactor-irradiated cladding tubes were examined by X-ray diffraction using synchrotron radiation. To reveal the stress state effect on hydride reorientation, the critical threshold stress to reorient hydrides was determined by designing novel mechanical test samples which produce a range of stress states from uniaxial to "near-equibiaxial" tension when a load is applied. The threshold stress was determined after thermo-mechanical treatments by

  4. Risk of Bias in Systematic Reviews of Non-Randomized Studies of Adverse Cardiovascular Effects of Thiazolidinediones and Cyclooxygenase-2 Inhibitors: Application of a New Cochrane Risk of Bias Tool.

    Directory of Open Access Journals (Sweden)

    Anja Bilandzic

    2016-04-01

    Full Text Available Systematic reviews of the effects of healthcare interventions frequently include non-randomized studies. These are subject to confounding and a range of other biases that are seldom considered in detail when synthesizing and interpreting the results. Our aims were to assess the reliability and usability of a new Cochrane risk of bias (RoB tool for non-randomized studies of interventions and to determine whether restricting analysis to studies with low or moderate RoB made a material difference to the results of the reviews.We selected two systematic reviews of population-based, controlled non-randomized studies of the relationship between the use of thiazolidinediones (TZDs and cyclooxygenase-2 (COX-2 inhibitors and major cardiovascular events. Two epidemiologists applied the Cochrane RoB tool and made assessments across the seven specified domains of bias for each of 37 component studies. Inter-rater agreement was measured using the weighted Kappa statistic. We grouped studies according to overall RoB and performed statistical pooling for (a all studies and (b only studies with low or moderate RoB. Kappa scores across the seven bias domains ranged from 0.50 to 1.0. In the COX-2 inhibitor review, two studies had low overall RoB, 14 had moderate RoB, and five had serious RoB. In the TZD review, six studies had low RoB, four had moderate RoB, four had serious RoB, and two had critical RoB. The pooled odds ratios for myocardial infarction, heart failure, and death for rosiglitazone versus pioglitazone remained significantly elevated when analyses were confined to studies with low or moderate RoB. However, the estimate for myocardial infarction declined from 1.14 (95% CI 1.07-1.24 to 1.06 (95% CI 0.99-1.13 when analysis was confined to studies with low RoB. Estimates of pooled relative risks of cardiovascular events with COX-2 inhibitors compared with no nonsteroidal anti-inflammatory drug changed little when analyses were confined to studies with

  5. Particle shape effects on the stress response of granular packings.

    Science.gov (United States)

    Athanassiadis, Athanasios G; Miskin, Marc Z; Kaplan, Paul; Rodenberg, Nicholas; Lee, Seung Hwan; Merritt, Jason; Brown, Eric; Amend, John; Lipson, Hod; Jaeger, Heinrich M

    2014-01-01

    We present measurements of the stress response of packings formed from a wide range of particle shapes. Besides spheres these include convex shapes such as the Platonic solids, truncated tetrahedra, and triangular bipyramids, as well as more complex, non-convex geometries such as hexapods with various arm lengths, dolos, and tetrahedral frames. All particles were 3D-printed in hard resin. Well-defined initial packing states were established through preconditioning by cyclic loading under given confinement pressure. Starting from such initial states, stress-strain relationships for axial compression were obtained at four different confining pressures for each particle type. While confining pressure has the largest overall effect on the mechanical response, we find that particle shape controls the details of the stress-strain curves and can be used to tune packing stiffness and yielding. By correlating the experimentally measured values for the effective Young's modulus under compression, yield stress and energy loss during cyclic loading, we identify trends among the various shapes that allow for designing a packing's aggregate behavior.

  6. History effect on the Reynolds stress in turbulent swirling flow

    Science.gov (United States)

    Hamba, Fujihiro

    2017-02-01

    The eddy-viscosity model for turbulence has some difficulty in predicting rotating and swirling flows. Turbulent swirling flow in a straight pipe is a typical example. A rapidly rotating core in the pipe decays too quickly in results obtained from the standard k-ɛ model. The eddy viscosity needs to be reduced to predict the velocity profiles well; the mechanism of the decrease in the eddy viscosity has not been clarified yet. In this work, the eddy-viscosity model was investigated using a temporally nonlocal expression for the Reynolds stress that represents the history effect. A simple transport equation for the Reynolds stress was integrated along a mean-flow pathline to obtain a temporally nonlocal model for the Reynolds stress. The nonlocal model was applied to simple swirling flows for which the time integral can be further calculated to investigate the history effect. It was shown that the history effect associated with the rotating motion gives rise to a small factor in the expression for the eddy viscosity. In order to confirm the history effect, the present model and the linear eddy-viscosity model were used to simulate a swirling pipe flow. The velocity profiles obtained from the present model agree well with experimental results; the reduced eddy viscosity can account for the slow decay of the swirling motion in the core region. The anisotropic nature of the eddy viscosity was also discussed in relation to the small factor caused by the history effect.

  7. Effects of Stress on Students' Physical and Mental Health and Academic Success

    Science.gov (United States)

    Shankar, Nilani L.; Park, Crystal L.

    2016-01-01

    Stress affects students in multiple ways. This article provides a conceptual overview of the direct (e.g., psychoneuroimmunological, endocrine) and indirect (health behavior) pathways through which stress affects physical health, the psychological effects of stress on mental health, and the cognitive effects of stress (e.g., attention,…

  8. Size speed bias or size arrival effect-How judgments of vehicles' approach speed and time to arrival are influenced by the vehicles' size.

    Science.gov (United States)

    Petzoldt, Tibor

    2016-10-01

    Crashes at railway level crossings are a key problem for railway operations. It has been suggested that a potential explanation for such crashes might lie in a so-called size speed bias, which describes the phenomenon that observers underestimate the speed of larger objects, such as aircraft or trains. While there is some evidence that this size speed bias indeed exists, it is somewhat at odds with another well researched phenomenon, the size arrival effect. When asked to judge the time it takes an approaching object to arrive at a predefined position (time to arrival, TTA), observers tend to provide lower estimates for larger objects. In that case, road users' crossing decisions when confronted with larger vehicles should be rather conservative, which has been confirmed in multiple studies on gap acceptance. The aim of the experiment reported in this paper was to clarify the relationship between size speed bias and size arrival effect. Employing a relative judgment task, both speed and TTA estimates were assessed for virtual depictions of a train and a truck, using a car as a reference to compare against. The results confirmed the size speed bias for the speed judgments, with both train and truck being perceived as travelling slower than the car. A comparable bias was also present in the TTA estimates for the truck. In contrast, no size arrival effect could be found for the train or the truck, neither in the speed nor the TTA judgments. This finding is inconsistent with the fact that crossing behaviour when confronted with larger vehicles appears to be consistently more conservative. This discrepancy might be interpreted as an indication that factors other than perceived speed or TTA play an important role for the differences in gap acceptance between different types of vehicles.

  9. Energetic deposition of carbon in a cathodic vacuum arc with a biased mesh

    Science.gov (United States)

    Moafi, A.; Lau, D. W. M.; Sadek, A. Z.; Partridge, J. G.; McKenzie, D. R.; McCulloch, D. G.

    2011-04-01

    Carbon films were deposited in a filtered cathodic vacuum arc with a bias potential applied to a conducting mesh mounted in the plasma stream between the source and the substrate. We determined the stress and microstructural properties of the resulting carbon films and compared the results with those obtained using direct substrate bias with no mesh. Since the relationship between deposition energy and the stress, sp2 fraction and density of carbon are well known, measuring these film properties enabled us to investigate the effect of the mesh on the energy and composition of the depositing flux. When a mesh was used, the film stress showed a monotonic decrease for negative mesh bias voltages greater than 400V, even though the floating potential of the substrate did not vary. We explain this result by the neutralization of some ions when they are near to or passing through the negatively biased mesh. The microstructure of the films showed a change from amorphous to glassy carbonlike with increasing bias. Potential applications for this method include the deposition of carbon films with controlled stress on low conductivity substrates to form rectifying or ohmic contacts.

  10. Perceived heat stress and health effects on construction workers

    Directory of Open Access Journals (Sweden)

    Priya Dutta

    2015-01-01

    Full Text Available Introduction: Increasing heat waves-particularly in urban areas where construction is most prevalent, highlight a need for heat exposure assessment of construction workers. This study aims to characterize the effects of heat on construction workers from a site in Gandhinagar. Materials and Methods: This study involved a mixed methods approach consisting of a cross sectional survey with anthropometric measurements (n = 219 and four focus groups with construction workers, as well as environmental measurements of heat stress exposure at a construction site. Survey data was collected in two seasons i.e., summer and winter months, and heat illness and symptoms were compared between the two time periods. Thematic coding of focus group data was used to identify vulnerability factors and coping mechanisms of the workers. Heat stress, recorded using a wet bulb globe temperature monitor, was compared to international safety standards. Results: The survey findings suggest that heat-related symptoms increased in summer; 59% of all reports in summer were positive for symptoms (from Mild to Severe as compared to 41% in winter. Focus groups revealed four dominant themes: (1 Non-occupational stressors compound work stressors; (2 workers were particularly attuned to the impact of heat on their health; (3 workers were aware of heat-related preventive measures; and (4 few resources were currently available to protect workers from heat stress. Working conditions often exceed international heat stress safety thresholds. Female workers and new employees might be at increased risk of illness or injury. Conclusion: This study suggests significant health impacts on construction workers from heat stress exposure in the workplace, showed that heat stress levels were higher than those prescribed by international standards and highlights the need for revision of work practices, increased protective measures, and possible development of indigenous work safety standards for

  11. The Effect of Stress Management on Occupational Stress and Satisfaction among Midwives in Obstetrics and Gynecology Hospital Wards in Iran

    OpenAIRE

    Jahromi, Mahdi Karimyar; Minaei, Shahnaz; Abdollahifard, Sareh; Maddahfar, Majid

    2015-01-01

    Introduction: Occupational stress is one of the major problems of health care staff, substantially affecting their professional and personal performance. This research has been conducted with the aim of determining the effect of stress management on occupational stress and satisfaction among the Midwives in Obstetrics and Gynecology Hospital wards at Motahari Hospital in Jahrom, Iran 2013-2014. Methods: This is a Quasi-experimental study of the pre- and post-clinical trials type. The study po...

  12. Effect of sodium salicylate on oxidative stress andinsulinresistanceinducedbyfreefattyacids

    Institute of Scientific and Technical Information of China (English)

    Bing He; Sheng Zhao; Wei Zhang; Yan Li; Ping Han

    2010-01-01

    BACKGROUND: It has been reported that high-dose salicy-lates improve free fatty acids (FFAs)-induced insulin resistance andβ-cell dysfunction in vitro, but the mechanism remains uncertain. In insulin-resistant rats, we found that the supplementation of sodium salicylate is associated with a reduction of plasma malondialdehyde (MDA), a marker of oxidative stress. Few studies have investigated the effects of salicylates on oxidative stress levels in insulin-resistant animal models. This study aimed to assess the effect of sodium salicylate on insulin sensitivity and to explore the potential mechanism by which it improves hepatic and peripheral insulin resistance. METHODS: Intralipid+heparin (IH), saline (SAL), or intralipid+heparin+sodium salicylate (IHS) were separately infused for 7 hours in normal Wistar rats. During the last 2 hours of the infusion, hyperinsulinemic-euglycemic clamping was performed with [6-3H] glucose tracer. Plasma glucose was measured using the glucose oxygenase method. Plasma insulin and C-peptide were determined by radioimmunoassay. MDA levels and glutathione peroxidase (GSH-PX) activity in the liver and skeletal muscle were measured with colorimetric kits. RESULTS: Compared with infusion of SAL, IH infusion increased hepatic glucose production (HGP), and decreased glucose utilization (GU) (P CONCLUSIONS: Short-term elevation of fatty acids induces insulin resistance by enhancing oxidative stress levels in the liver and muscle. The administration of the anti-inlfammatory drug sodium salicylate reduces the degree of oxidative stress, therefore improving hepatic and peripheral insulin resistance. IKK-β and NF-κB provide potential pathogenic links to oxidative stress.

  13. Effect of additional sample bias in Meshed Plasma Immersion Ion Deposition (MPIID) on microstructural, surface and mechanical properties of Si-DLC films

    Science.gov (United States)

    Wu, Mingzhong; Tian, Xiubo; Li, Muqin; Gong, Chunzhi; Wei, Ronghua

    2016-07-01

    Meshed Plasma Immersion Ion Deposition (MPIID) using cage-like hollow cathode discharge is a modified process of conventional PIID, but it allows the deposition of thick diamond-like carbon (DLC) films (up to 50 μm) at a high deposition rate (up to 6.5 μm/h). To further improve the DLC film properties, a new approach to the MPIID process is proposed, in which the energy of ions incident to the sample surface can be independently controlled by an additional voltage applied between the samples and the metal meshed cage. In this study, the meshed cage was biased with a pulsed DC power supply at -1350 V peak voltage for the plasma generation, while the samples inside the cage were biased with a DC voltage from 0 V to -500 V with respect to the cage to study its effect. Si-DLC films were synthesized with a mixture of Ar, C2H2 and tetramethylsilane (TMS). After the depositions, scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectrons spectroscopy (XPS), Raman spectroscopy and nanoindentation were used to study the morphology, surface roughness, chemical bonding and structure, and the surface hardness as well as the modulus of elasticity of the Si-DLC films. It was observed that the intense ion bombardment significantly densified the films, reduced the surface roughness, reduced the H and Si contents, and increased the nanohardness (H) and modulus of elasticity (E), whereas the deposition rate decreased slightly. Using the H and E data, high values of H3/E2 and H/E were obtained on the biased films, indicating the potential excellent mechanical and tribological properties of the films. In this paper, the effects of the sample bias voltage on the film properties are discussed in detail and the optimal bias voltage is presented.

  14. Negative magnetization and zero-field cooled exchange bias effect in Co0.8Cu0.2Cr2O4 ceramics

    Science.gov (United States)

    Wang, L. G.; Zhu, C. M.; Tian, Z. M.; Luo, H.; Bao, D. L. G. C.; Yuan, S. L.

    2015-10-01

    The negative magnetization and zero-field cooled exchange bias (ZFC EB) effect are observed in Co0.8Cu0.2Cr2O4 polycrystalline ceramics. 20% Cu substitution for Co in CoCr2O4 leads to the evident magnetization reversal at the compensation temperature (Tcomp ˜ 50 K) with applied magnetic field of 500 Oe. Besides, Tcomp decreases monotonously with increasing applied field, and the negative magnetization finally disappears when the field increases to 9000 Oe. Different temperature dependence of sublattice magnetization at different crystallographic sites is proved to induce the magnetization reversal. In addition, ZFC EB effect can be tuned by measuring temperature and presents the maximum of exchange bias field (HEB) with ˜2300 Oe at 50 K. This unconventional EB effect can be attributed to the coupling interaction between the two sublattices.

  15. Ratio Bias and Policy Preferences

    DEFF Research Database (Denmark)

    Pedersen, Rasmus Tue

    2016-01-01

    Numbers permeate modern political communication. While current scholarship on framing effects has focused on the persuasive effects of words and arguments, this article shows that framing of numbers can also substantially affect policy preferences. Such effects are caused by ratio bias, which is ...

  16. Ageing under Shear: Effect of Stress and Temperature Field

    Science.gov (United States)

    Shukla, Asheesh; Joshi, Yogesh M.

    2008-07-01

    In this work we studied the effect of oscillatory stress and temperature on the ageing dynamics of aqueous suspension of laponite. At the higher magnitude of stress, elastic and viscous moduli of the system underwent a sharp rise with the ageing time. The age at the onset of rise and the sharpness of the same increased with the magnitude of stress. We propose that at the beginning of ageing, the strain associated with the oscillatory stress field affects the lower modes in the relaxation time distribution. The higher modes, which are not significantly affected by the deformation field, continue to grow increasing the viscosity of the system thereby lowering the magnitude of the deformation field. Progressive decrease in the later reduces the range of relaxation modes affected by it. This dynamics eventually leads to an auto-catalytic increase in the elastic and viscous moduli. An increase in temperature accelerates the ageing process by shifting the ageing dynamics to a lower ageing time. This is due the microscopic relaxation dynamics, which causes ageing, becomes faster with increase in the temperature.

  17. The effect of social stress on salivary trace elements.

    Science.gov (United States)

    Sheibaninia, Ahmad

    2014-12-01

    Social stress can alter the saliva in favor of metabolism of trace elements. This study aimed to assess the effect of social stress on salivary copper (Cu), zinc (Zn), manganese (Mn), and iron (Fe) contents in dental students before and after a comprehensive English test. Twelve students with an average age of 27 years were selected from three dental schools. The students were carries-free, and salivary samples were collected 1 week before the test day and right before the comprehensive English test. Unstimulated saliva was collected from the participants. The pH of the saliva samples was measured using a portable pH meter, and the salivary trace element contents were determined using an atomic absorption spectrophotometer. After checking data to be normally distributed, Student's paired t test was used for statistical analysis. Salivary pH significantly increased right before the English test. Salivary Cu concentration decreased in students after the test (P > 0.05). The level of Zn, Mn, and Fe increased, while only Mn change was statistically significant (P stress led to a significant increase in Mn concentration in the saliva. The salivary Cu, Zn, and Fe contents, however, did not exhibit significant changes. Changes in salivary inorganic trace element content, as a result of physiological stress, might influence health of teeth, enamel, and oral mucosal tissues.

  18. Lasting anxiogenic effects of feline predator stress in mice: sex differences in vulnerability to stress and predicting severity of anxiogenic response from the stress experience.

    Science.gov (United States)

    Adamec, Robert; Head, David; Blundell, Jacqueline; Burton, Paul; Berton, Olivier

    2006-06-15

    Previous work in male Swiss Webster (CFW) mice demonstrated a long lasting effect of predator stress on risk assessment in the elevated plus maze (EPM). Most severe effects (increases in risk assessment) were seen following a brief unprotected exposure to a cat. Lesser effects were produced by a brief exposure of mice to the cat exposure room without a cat in the room (room stress). This graded response is analogous to the covariation of symptom severity and severity of the precipitating stressor in posttraumatic stress disorder (PTSD). The present study extended these findings to another strain of mice, C57/BL6, and a broader range of tests of anxiety-like behavior, including EPM, acoustic startle response and light/dark box test. Sex was introduced as a variable to investigate if females might be more susceptible to the effects of stressors than males, as has been suggested in human PTSD. Graded and lasting (7 days) effects of a 10 min exposure to a cat (predator stress) or to the cat exposure room only (room stress) were observed on lighted chamber avoidance in the light/dark box. Room stress was without effect on startle responses, but predator stress enhanced peak startle amplitudes measured in the light or in the dark. There was no evidence of light-enhancement of startle in C57 mice. Female mice were more susceptible to the effects of predator and room stress, depending on the measure. Females only responded to cat exposure with a lasting increase in average startle amplitude. This was due to an increased and more prolonged multipeak response to startle after the first and maximal peak startle response. In addition, in females, room and predator stress were equally anxiogenic in measures of open arm avoidance in the EPM. In contrast, room stress was without effect on open arm avoidance in males, but cat exposure was as anxiogenic in males as it was in females. These findings suggest EPM anxiety in females is affected more by the milder stress of room

  19. Weibull Effective Area for Hertzian Ring Crack Initiation Stress

    Energy Technology Data Exchange (ETDEWEB)

    Jadaan, Osama M. [University of Wisconsin, Platteville; Wereszczak, Andrew A [ORNL; Johanns, Kurt E [ORNL

    2011-01-01

    Spherical or Hertzian indentation is used to characterize and guide the development of engineered ceramics under consideration for diverse applications involving contact, wear, rolling fatigue, and impact. Ring crack initiation can be one important damage mechanism of Hertzian indentation. It is caused by sufficiently-high, surface-located, radial tensile stresses in an annular ring located adjacent to and outside of the Hertzian contact circle. While the maximum radial tensile stress is known to be dependent on the elastic properties of the sphere and target, the diameter of the sphere, the applied compressive force, and the coefficient of friction, the Weibull effective area too will be affected by those parameters. However, the estimations of a maximum radial tensile stress and Weibull effective area are difficult to obtain because the coefficient of friction during Hertzian indentation is complex, likely intractable, and not known a priori. Circumventing this, the Weibull effective area expressions are derived here for the two extremes that bracket all coefficients of friction; namely, (1) the classical, frictionless, Hertzian case where only complete slip occurs, and (2) the case where no slip occurs or where the coefficient of friction is infinite.

  20. Alleviation Effects of Rare Earth on Cd Stress to Rape

    Institute of Scientific and Technical Information of China (English)

    马建军; 张淑侠; 朱京涛; 吴贺平

    2004-01-01

    Using rapes as test materials, the fastness expression and alleviation effect of rapes were studied under Cd stress condition, as the rapeseeds were dipped in the single element(La, Ce, Nd, Pr)and mixed rare earth(RE). The results indicate that, under Cd stress, the dry and fresh weight are increased by both the single element and mixed rare earth treatment, and the fastness of rape is improved.The single element of rare earth decreases the Cd content in rape roots and transmits Cd to the edible parts above the ground in which the alleviation effect of Ce is most significant.La treatment takes the second place, so that the poisonous effect of heavy metal Cd is eased.The mixed rare earth doesn't alleviate the assimilation of Cd in rape roots, but accelerates the transfer of Cd to the parts above the ground. The research puts forward that the alleviation of rare earth on Cd stress has connection with the decrease of Ca content.