Littérature scientifique sur le sujet « Bottom-up bias effect »

Ambiguous figures are pictures which reverse their appearance during prolonged viewing and can be perceived in two (or more) available interpretations. Explanations for this phenomenon favour either early bottom-up processes or higher-level top-down processes. This study aimed to investigate the perception of simultaneously presented neutral and biased (i.e. with a slight modification towards one or another of the available interpretations) ambiguous figures. Our results have indicated that observers tend to perceive two adjacent identical figures as reversing simultaneously, and the same percepts dominated both in the reversal rate and the duration of perception. In the case of biased and neutral figures presented in pairs, modifications of interpretation either increased or decreased the frequency of a biased percept. The results show that both bottom-up and top-down perceptual processes influence the perception of ambiguous figures.Key words: ambiguous figure, adaptation, multiple-figure presentation, bias, visual perceptionTENDENCIJOS ĮTAKA DVIEJŲ DVIPRASMIŲ FIGŪRŲ SUVOKIMUIMonika Intaitė, Alvydas Šoliūnas, Ona Gurčinienė, Osvaldas Rukšėnas SantraukaDviprasmės figūros yra vaizdai, kuriuos stebint ilgesnį laiką keičiasi jų suvokimas – galimos dvi (ar daugiau) jo interpretacijos. Šis fenomenas aiškinamas arba ankstyvesniais vadinamaisiais bottom-up procesais, arba aukštesnio lygio vadinamaisiais top-down procesais. Šiame straipsnyje tiriama, kaip vyksta vienu metu pateikiamų dviejų figūrų – vienos dviprasmės, kitos dviprasmės modifikuotos taip, kad viena interpretacijų yra išryškinta, suvokimas. Rezultatai parodė, kad dviejų šalia esančių nemodifikuotų dviprasmių figūrų suvokiamos interpretacijos keičiasi kartu, o viena interpretacijų dominuoja tiek pagal trukmę, tiek pagal dažnį. Figūros modifikavimas dažniausiai sumažindavo priešingos nei išryškinta interpretacijos suvokimą. Stipriausias efektas buvo stebint Bugelskio piešinį žmogus-žiurkė, mažiausias – Rubino piešinį vaza-veidai. Dažnesnį ir ilgesnį išryškintos interpretacijos suvokimą galbūt maskavo faktas, kad figūros modifikavimas dažnais atvejais padidindavo skirtingų interpretacijų suvokimą vienu metu, kai viena figūra suvokiama vienokia prasme, kita – kitokia. Rezultatai gali būti aiškinami tuo, kad tiek bottom-up, tiek top-down procesai turi įtakos dviprasmių figūrų suvokimui.

The stream-bounce effect refers to a bistable motion stimulus that is interpreted as two targets either “streaming” past or “bouncing” off one another, and the manipulations that bias responses. Directional bias, according to Bertenthal et al., is an account of the effect proposing that low-level motion integration promotes streaming, and its disruption leads to bouncing, and it is sometimes cited either directly in a bottom-up fashion or indirectly under top-down control despite Sekuler and Sekuler finding evidence inconsistent with it. We tested two key aspects of the hypothesis: (a) comparable changes in speed should produce comparable disruptions and lead to similar effects; and (b) speed changes alone should disrupt integration without the need for additional more complex changes of motion. We found that target motion influences stream-bounce perception, but not as directional bias predicts. Our results support Sekuler and Sekuler and argue against the low-level motion signals driving perceptual outcomes in stream-bounce displays (directly or indirectly) and point to higher level inferential processes involving perceptual history and expectation. Directional bias as a mechanism should be abandoned and either another specific bottom-up process must be proposed and tested or consideration should be given to top-down factors alone driving the effect.

Genetic coessentiality analysis, a computational approach which identifies genes sharing a common effect on cell fitness across large-scale screening datasets, has emerged as a powerful tool to identify functional relationships between human genes. However, widespread implementation of coessentiality to study individual genes and pathways is limited by systematic biases in existing coessentiality approaches and accessibility barriers for investigators without computational expertise. We created FIREWORKS, a method and interactive tool for the construction and statistical analysis of coessentiality networks centered around gene(s) provided by the user. FIREWORKS incorporates a novel bias reduction approach to reduce false discoveries, enables restriction of coessentiality analyses to custom subsets of cell lines, and integrates multiomic and drug–gene interaction datasets to investigate and target contextual gene essentiality. We demonstrate the broad utility of FIREWORKS through case vignettes investigating gene function and specialization, indirect therapeutic targeting of “undruggable” proteins, and context-specific rewiring of genetic networks.

ABSTRACTPolysilsesquioxane passivation layers were used to passivate bottom gate a-InGaZnO (a-IGZO) thin film transistors (TFT). The a-IGZO TFTs passivated with polysilsesquioxane showed highly stable behavior during positive bias stress, negative bias stress, and negative bias illumination stress. A voltage threshold shift of up to 0.1 V, less than -0.1 V and -2.3 V for positive bias stress, negative bias stress, and negative bias illumination stress, respectively. We also report the effect of reactive ion etching (RIE) on the electrical characteristics of a-InGaZnO (a-IGZO) thin-film transistors (TFT) passivated with the polysilsesquioxane-based passivation layers. We show how post-annealing treatment using two different atmosphere conditions: under O2 ambient and combination of N2 and O2 ambient (20% O2), can be performed to recover the initial characteristics. Furthermore, we present a highly stable novel polysilsesquioxane photosensitive passivation material that can be used to completely circumvent the reactive ion etching effects.

Purpose This study aims to investigate the following three issues: whether consumers process numeric information with locational cues, which locations (horizontal vs vertical) are more influential in processing numbers and whether a number-location association is weakened or strengthened when a visual reference frame moves up or down. Design/methodology/approach A field study and a series of three lab experiments were conducted to examine the location effect of numeric information on the package façade on the perceived magnitude of a number. Findings The authors found that a number at the right was perceived as larger than one at the left only when the number is located at the bottom. Also, placing numeric information at the bottom rather than the top of a product package façade was more powerful in processing the numeric information, but this is true only when the visual frame is set lower. Practical implications This study provides practical insights for product managers in placing core numeric information on product packaging to effectively communicate product value to consumers. Optimal locations can be deliberately considered along with types of numeric information and product categories. For healthy products that promote fewer calories, the top area of the package façade may be a better position for placing information on calories per serving to make the product more appealing to those who follow a healthy diet. Heavier, more voluminous products (e.g., refrigerator) better position their volume/weight information at the bottom than at the top or at the right of the bottom than at the left of the bottom on the product facade. Either the left side or right side of the top position may be beneficial for thinner, lightweight products (e.g., television). Originality/value The present work adds valuable empirical findings; inconsistent with past research, left-right location-number associations are not always true. People tend to associate smaller numbers with left-side locations and larger numbers with right-side locations only when the number is located at the bottom. Also, the study reported that top-small, bottom-large associations are not always true. The difference in perceived magnitude of the number between a number at the top and one at the bottom within the visual frame is significant only when the visual frame is set close to the ground.

Selective visual attention requires an efficient coordination between top–down and bottom–up attention control mechanisms. This study investigated the behavioral and neural effects of top–down focused spatial attention on the coding of highly salient distractors and their tendency to capture attention. Combining spatial cueing with an irrelevant distractor paradigm revealed bottom–up based attentional capture only when attention was distributed across the whole search display, including the distractor location. Top–down focusing spatial attention on the target location abolished attentional capture of a salient distractor outside the current attentional focus. Functional data indicated that the missing capture effect was not based on diminished bottom–up salience signals at unattended distractor locations. Irrespectively of whether salient distractors occurred at attended or unattended locations, their presence enhanced BOLD signals at their respective spatial representation in early visual areas as well as in inferior frontal, superior parietal, and medial parietal cortex. Importantly, activity in these regions reflected the presence of a salient distractor rather than attentional capture per se. Moreover, successfully inhibiting attentional capture of a salient distractor at an unattended location further increased neural responses in medial parietal regions known to be involved in controlling spatial attentional shifts. Consequently, data provide evidence that top–down focused spatial attention prevents automatic attentional capture by supporting attentional control processes counteracting a spatial bias toward a salient distractor.

Background and objectives: Hemispatial neglect is a common consequence of stroke, with an estimated incidence of 23%. Interventions for treating hemispatial neglect may be categorized as either top-down or bottom-up processing. The aim of top-down approaches is to train the person to voluntarily compensate for their neglect. Such approaches require awareness of the disorder and a high level of active participation by the patient. Differently, bottom-up approaches are based on manipulation of a patient’s sensory environment and so require less awareness of behavioral bias. In line with the latter, it is conceivable that elastic therapeutic taping applied to the left neck surface may provide bottom-up inputs that reduce hemispatial neglect symptoms. The aim of this study was to assess the effect of therapeutic neck taping on visuo-spatial abilities, neck motion, and kinesthetic sensibility in chronic stroke patients with hemispatial neglect. Materials and Methods: After randomization, 12 chronic stroke patients with hemispatial neglect received 30 consecutive days of real (treatment group) or sham (control group) neck taping. The outcomes were as follows: Stars Cancellation Test; neck active range of motion; Letter Cancellation Test; Comb and Razor Test; Cervical Joint Position Error Test evaluated before and after one month of taping. Results: Between-group comparison showed significant differences only for the Cervical Joint Position Error Test after treatment (p = 0.009). Conclusions: Our preliminary findings support the hypothesis that neck taping might improve cervicocephalic kinesthetic sensibility in chronic stroke patients with hemispatial neglect. Further studies are needed to strengthen our results and better investigate the effects of elastic therapeutic taping on visuo-spatial abilities in stroke patients with hemispatial neglect.

Conventional sintering and direct ball milling of Bi 2 O 3 + Fe 2 O 3 mixture were used for the fabrication of BiFeO 3 powders. The fabricated powders were performed annealing or high energy ball milling to vary the grain size from bottom-up or top-down. It was found that the magnetization of the powders synthesized by both methods plotted with the reciprocal of the grain size could be linearly fitted, indicating that the magnetism is from the finite size effect. Exchange bias phenomenon was observed after field cooling (FC) of the powders, confirming the magnetization is due to the uncompensated or canted surface spins. No spin glass behavior was found in these powders.

Abstract. We developed a top-down methodology combining the inversed chemistry transport modeling and satellite-derived tropospheric vertical column of NO2 and estimated the NOx emissions of the Yangtze River Delta (YRD) region at a horizontal resolution of 9 km for January, April, July, and October 2016. The effect of the top-down emission estimation on air quality modeling and the response of ambient ozone (O3) and inorganic aerosols (SO42-, NO3-, and NH4+, SNA) to the changed precursor emissions were evaluated with the Community Multi-scale Air Quality (CMAQ) system. The top-down estimates of NOx emissions were smaller than those (i.e., the bottom-up estimates) in a national emission inventory, Multi-resolution Emission Inventory for China (MEIC), for all the 4 months, and the monthly mean was calculated to be 260.0 Gg/month, 24 % less than the bottom-up one. The NO2 concentrations simulated with the bottom-up estimate of NOx emissions were clearly higher than the ground observations, indicating the possible overestimation in the current emission inventory, attributed to its insufficient consideration of recent emission control in the region. The model performance based on top-down estimate was much better, and the biggest change was found for July, with the normalized mean bias (NMB) and normalized mean error (NME) reduced from 111 % to −0.4 % and from 111 % to 33 %, respectively. The results demonstrate the improvement of NOx emission estimation with the nonlinear inversed modeling and satellite observation constraint. With the smaller NOx emissions in the top-down estimate than the bottom-up one, the elevated concentrations of ambient O3 were simulated for most of the YRD, and they were closer to observations except for July, implying the VOC (volatile organic compound)-limited regime of O3 formation. With available ground observations of SNA in the YRD, moreover, better model performance of NO3- and NH4+ was achieved for most seasons, implying the effectiveness of precursor emission estimation on the simulation of secondary inorganic aerosols. Through the sensitivity analysis of O3 formation for April 2016, the decreased O3 concentrations were found for most of the YRD region when only VOC emissions were reduced or the reduced rate of VOC emissions was 2 times of that of NOx, implying the crucial role of VOC control in O3 pollution abatement. The SNA level for January 2016 was simulated to decline 12 % when 30 % of NH3 emissions were reduced, while the change was much smaller with the same reduced rate for SO2 or NOx. The result suggests that reducing NH3 emissions was the most effective way to alleviate SNA pollution of the YRD in winter.

My thesis concerns multistable visual phenomena. Multistability refers to the phenomenon of perceptual switching perception between possible interpretations of an unchanging stimulus.This topic has received attention especially during the last half of the XX century but still there is no common agreement about the underlying processes. Indeed the multistable perception processes have been categorized as bottom-up and top-down theories (automatic vs. cognitive processes). In order to investigate the neural substrates involved in the perceptual reversal tasks, two experiment were performed by means transcranial magnetic stimulation (TMS). In the first experiment has been investigated the involvement of the right dorsolateral prefrontal cortex and occipitotemporal cortex in perceptual reversal, by means repetitive transcranial magnetic stimulation (rTMS). Thirty right- participants (fourteen males) took part in the study. 1 Hz rTMS (off-line, 10% submotor threshold) was administered for 600s before the task Subjects were divided in three groups depending on the stimulation condition: Group 1: rTMS applied over the right dorsolateral prefrontal cortex; Group 2: occipito-temporal cortex; Group 3: Sham. After rTMS, a total of 110 black-white images (6X9, 9X6, 9x9) were randomly presented: 34 figure-ground reversible images, the same 34 disambiguate images, and 21 non-reversible images and the same 21 neutral modified images. The subject had to decide whether the image was reversible or neutral. A repeated measures Anova with group (frontal, occipito-temporal, sham) as between subjects variable and image (reversible, disambiguated, neutral) as within subjects variable was run on RTs of correct trials and on accuracy. Both the main effect of group and image were significant (p= .011; p< .0001) the interaction group x image was also significant (p= .001) on RTs. Post-hoc tests highlighted slower RTs for disambiguated and neutral images in the frontal group as compared to the occipito-temporal group (p= .014 and p= .016) and sham group (p= .019 and p= .006). In the case of accuracy, the main effect of image was significant (p< .001). The aim of the second experiment was to clarify the results of the previous one. Specifically, the goal was to understand if the presence of disambiguated and neutral image could influence the recognition of reversible pictures. Then in this experiment only reversible image were showed. 1 Hz rTMS (off-line, 10% submotor threshold) was administered for 900s before the task. Subjects were divided as in the previous experiment. After rTMS, a total of 84 figure-ground reversible pictures (6X9, 9X6, 9x9) were randomly presented. The stimuli were all black and white. Each trial consisted of a fixation cross at the center of the screen for 500 ms, followed by the appearance of the stimulus. The subject had to press (with his/her right hand) the button on the keyboard when he/she was able to reverse the figure and ground. Then, the subject had to describe both percepts in the picture. Several practice trials were presented, in order to familiarize with the procedure and the type of stimuli. A one-way Anova with group (frontal, occipito-temporal, sham) as independent variable showed significant effects of group on RTs of correct trials and on accuracy. The frontal group showed slower RTs than occipito-temporal and sham group (both p < 0.05) and a mean of correct responses significantly lower than other two groups (p< 0.05). Results showed that the dorsolateral prefrontal cortex is involved in perceptual reversal processes. rTMS applied on the dorsolateral prefrontal cortex affects the ability to switch between percepts, and to select between the neutral and reversible image. Results supported the "top-down" hypothesis, which suggests that reversal takes place during perceptual interpretation, therefore, at the highest level of visual hierarchy.

Ming Yan of Sun Yat-sen University, Guangzhou, optimized (Synlett 2010, 266) the organocatalyzed addition of 2 to a cyclic enone 1, establishing the cyclopropane 3 with high diastereo- and enantiocontrol. Benjamin List of the Max-Planck-Institut Mülheim devised (Angew. Chem. Int. Ed. 2010, 49, 4136) an organocatalyst for the enantioselective methanolysis of the anhydride 4. Other ring sizes worked as well. Hisashi Yamamoto of the University of Chicago reported (Organic Lett. 2010, 12, 2476) the organocatalyzed addition of the ketone silyl enol ether 6 to the aldehyde 7, to give the syn aldol product 8 in high ee. Gang Zhao of the University of Science and Technology, Hefei, established (Angew. Chem. Int. Ed. 2010, 49, 4467) an organocatalyst for the enantioselective addition of the allene ester 10 to 9. Marcus A. Tius of the University of Hawaii uncovered (J. Am. Chem. Soc. 2010, 132, 8266) conditions for the enantioselective Nazarov cyclization of 12 to 13. Karl A. Scheidt of Northwestern University devised (Organic Lett. 2010, 12, 2830) an easily scaled protocol for the cyclization of the prochiral diketone 14 to the β-lactone 15. Thermolysis then converted 15 to the corresponding cyclopentene. Yixin Lu of the National University of Singapore showed (Organic Lett. 2010, 12, 2278) that the simple combination of commercial cinchonidine with (+)-camphorsulfonic acid gave a catalyst that effected the room-temperature conjugate addition of 16 to 1. Hiyoshizo Kotsuki of Kochi University combined (Organic Lett. 2010, 12, 1616) 1,2-diaminocyclohexane with cyclohexane-1,2-bis carboxylate to give a similarly simple catalyst system, that effected Robinson annulation of 18 to 20. Binding an organocatalyst to a polymer simplifies recovery and reuse. Tore Hansen of the University of Oslo reported (J. Org. Chem. 2010, 75 , 1620) a bottom-up approach to such polymer-bound catalysts. The bound proline worked well for the condensation of 21 with 22. The corresponding polymeric diphenyl OTMS (Jørgensen-Hayashi) catalyst was sluggish, but it effected the three-component coupling of 24, 25, and 26 in high ee. Two cascade cyclizations warrant particular mention. The racemic cyclization of 28 is expected to be facile in the presence of HCl.

Abstract Nuclear power plant (NPP) accidents can cause severe effects. In order to ensure the normal operation of NPP, instrument and control system (I&C) composed of multiple sensors plays an important role in it. The sensor consists of sensitive components and functional circuits. In this paper, temperature sensor commonly used in NPP, PT100, is used as an example, and a bottom-up based physical analysis method is used to review the degradation mechanism and physical model of key components in resistance temperature detector (RTD) circuits. Resistors, capacitors, and MOSFETs are the key components of sensor circuits. Thin film resistors are the most widely used resistors due to their good performance. The transformed Arrhenius’ equation is used to describe its degradation characteristics. For the most commonly used aluminum electrolytic capacitors, the model reviewed in this paper can accurately describe the changes in equivalent series resistance (ESR), and use this as a criterion for determining capacitor failure. MOS technology is widely used in analog circuits. We have summarized three physical degradation processes, channel hot carrier (CHC), negative bias temperature instability (NBTI), and time-dependent dielectric breakdown (TDDB), that affect MOSFET performance. The physical model of the key component degradation of the sensor circuit summarized in this paper provides a basis for the subsequent establishment of a circuit-level degradation model.

Abstract The paper presents a solution to the problem of qualitative determination of actual downhole loads and drilling parameters optimization performed employing a dynamic digital well model. The problem of the surface and downhole sensors data quality is disclosed, a solution for an aggregated data QAQC and achieved results are presented. The implementation of the digital platform and the functionality of the dynamic digital twin allowed us to improve the compliance with desired regimes, enabled ensuring the safety of technological operations, allowed us to speed up decision-making while drilling and well completion and commissioning into production. The digital ecosystem allows to timely respond and control operational parameters, to improve and accurately control ROP while minimizing drilling hazards risks and premature drill bit bits wear. The incorporated dynamic digital twin in real-time allows assuring data quality, analyzing activities efficiency, and defining the optimal drilling parameters. The selection of optimal drilling parameters and an increase in ROP are carried out in real-time, based on the analysis of specific mechanical energy. Quality control of sensors plays a key role in the process of evaluating effective weight to bit and associated loads, and in identifying the current friction factor values exhibited downhole. Further on performed trend analysis of the friction factors and respective changes in key drilling parameters allows to track and prevent critical overloads of the drill string, permits to determine the risks of downhole hazards, enables evaluation of well circulation and conditioning activities efficiency in a given interval – allows reducing invisible NPT and the risks of downhole complications. The introduction of a digital ecosystem and a dynamic digital twin allowed us to bring the well construction management process to the next level. Operational response and the decision-making process has been drastically accelerated and improved. Uncertainties associated with an expert's interpretation of drilling states, and subjectivity in the opinions on the effectiveness of processes were eliminated. The negative effect of the human factor and the resulting invisible nonproductive time was minimized. In a short period, the drilling contractor was able to integrate a single digital platform, improve key performance indicators, and involve the field personnel in the full cycle of the technological process of well construction. Field and office personnel, including the driller, can work in a single digital platform, and regardless of the current operation, do always know the true downhole loads, do see the allowable operating envelope and optimal values of the hook load, surface torque, SPP, flow rate, RPM, weight, and torque on the bit, ROP and tripping speeds. The presented method of assessing the quality of the readings of measuring devices and determining the true WOB allows us to optimize the technological parameters during actual drilling. The calculation of the specific mechanical energy is performed based on effective downhole loads transferred to the drill bit. An abnormal increase in the specific mechanical energy notifies the driller to promptly correct the parameters and restore the efficient drilling process. The friction factors are automatically determined during rotation off bottom and tripping operations. Safe corridors and the operational roadmap are re-evaluated every second and are dynamically updated according to the current state of the wellbore and depths.