Artykuły w czasopismach na temat „Flashing light control”

Pursuing new display techniques based on insights into human visual perception can reveal new possibilities for visual information devices. Here, we propose a novel information presentation technique that exploits the perceptional features during rapid eye movements called saccades by using a fast remote eye-measuring method. When light sources are fixed on a vertical line, and the flashing pattern is changed quickly during a horizontal saccade, 2D images can be perceived due to spatio-temporal integration in the human vision system. We use this phenomenon to present 2D images with only one-dimensional light sources, and to show these images even in midair. The flashing cycle and flash timing of light sources are important elements in developing the design theory for this display technique. The flashing cycle determines the maximum resolution of a perceived 2D image. The flash timing is a crucial issue for our purpose because 2D images are perceived only when the timing of the saccade coincides with the flash timing. Therefore, in this paper, we describe the relationship between a flashing cycle and the maximum resolution of a perceived 2D image, and then propose a concise saccade detection method. By using this method, saccades can be detected and the light sources can be flashed within the saccade interval as it occurs in real time, and 2D images can be successfully presented.

SUMMARY Although many aspects of firefly bioluminescence are understood, the mechanism by which adult fireflies produce light as discrete rapid flashes is not. Here we examine the most postulated theory, that flashing is controlled by gating oxygen access to the light-emitting cells (photocytes). According to this theory, the dark state represents repression of bioluminescence by limiting oxygen, which is required for bioluminescence; relief from this repression by transiently allowing oxygen access to the photocytes allows the flash. We show that normobaric hyperoxia releases the repression of light emission in the dark state of both spontaneously flashing and non-flashing fireflies, causing continual glowing, and we measure the kinetics of this process. Secondly, we determine the length of the barriers to oxygen diffusion to the photocytes in the aqueous and gas phases. Thirdly, we provide constraints upon the distance between any gas-phase gating structure(s) and the photocytes. We conclude from these data that the flash of the adult firefly is controlled by gating of oxygen to the photocytes, and demonstrate that this control mechanism is likely to act by modulating the levels of fluid in the tracheoles supplying photocytes, providing a variable barrier to oxygen diffusion.

The complex environment at grade crossings and the severe collision consequences give rise to the concern of safety condition at crossings among traffic control authorities. Optimizing conventional devices and applying emerging technologies are worthwhile measures to improve the safety conditions at grade crossings. In this study, a flashing-light running (FLR) warning system was proposed to reduce crossing violation and improve performances of drivers at flashing-light-controlled grade crossings (FLCGCs). Forty-four fully licensed drivers aged between 30 and 48 years participated in a driving simulator study to investigate the efficacy of two countermeasures of the system: proposed design of signs and pavement markings (PSM) for grade crossing, and two-stage in-vehicle audio warning (IVAW) technology. A range of flashing light trigger timing and two foggy conditions were designed in this experiment to test the system applicability. Drivers’ gender and vocation were considered as well to examine drivers’ adaptation to the new proposed system. Five variables were collected and analyzed in this study to investigate the effectiveness of the system, i.e., drivers’ compliance, approaching mean speed, brake reaction time, deceleration, and red-to-crossing time. Results showed that drivers’ driving performances were improved in both PSM only condition and PSM + W condition. The FLR warning system could eliminate the negative effects of foggy weather and reduce gender differences in driver behaviors to some extent. These findings suggested that the FLR warning system has a potential to reduce the probability of grade crossing collisions.

The article discusses the train signaling system developed in OSŻD. The traffic light signaling currently used on the network managed by PKP Polskie Linie Kolejowe S.A. (Polish Railway Lines) is also described. A proposal of traffic light signals is presented, enabling the transmission of information on travel speeds on the turning tracks of turnouts operated on the PKP PLK S.A. network. The proposed signaling has been developed based on OSŻD (in Rus. Организация со-трудничества железных дорог – ОСЖД) signaling. The number of signals needed was obtained by introducing a second yellow light strip and optionally two different flashing frequencies. Keywords: railway signaling, signaling for trains, lineside signals, railway traffic control devices

More than 2,000 crashes and 239 fatalities were reported at public passive highway-railroad grade crossings in 1994. Driver error, often due to a breakdown in communication between traffic control devices and the driver, is commonly cited as a factor in passive grade crossing crashes. The objective of this study was to evaluate an improved method for communicating with drivers in an effort to improve safety at passive grade crossings. Specifically, this study evaluated the effectiveness of a vehicle-activated strobe light and supplemental sign as enhancements to the railroad advance (W10-1) warning sign at a passive highway-railroad grade crossing near Temple, Texas. Three study methods were used to evaluate this enhanced sign system including a before and after speed study, a driver survey, and a driver observation study. The results indicated that average speeds on the approaches to the grade crossing were lower after the installation of the enhanced sign system. Drivers responded favorably to the enhanced sign system, and no adverse driver reactions were observed at the onset of the flashing strobe light. The strobe light was effective in directing drivers’ attention to the railroad advance warning and supplemental signs. The enhanced sign system appears to increase driver awareness of the passive grade crossing, cause some drivers to approach the grade crossing with additional caution, and reduce the average speed near the nonrecovery zone on both approaches.

When the beam is transmitting, the random fluctuation motion of temperature and pressure of the medium inside the path of transmission will cause the random fluctuation of the index of refraction of the transmission medium. It will form wave front distortion when the beam is transmitting, which is known as the laser transmission turbulence effect. This effect mainly behaves as light intensity flashing, beam drift, phase fluctuation and beam expanding. Using FLUENT software simulate the status of turbulent gas in the environment with small space and large temperature difference (650°C). Verifying the laser transmission turbulence effect can be inhibited by artificial control the distribution of the gas flow inside the flow field, which can optimal the design of the instrument.

This paper deals with a design and implementation of optical defensive device for protection of aviation personnel. The design is built on the basic characteristics of human eyesight, illumination sensing of the environment, and microcontroller implementation for adaptation over sensed power, flash duration, and person distance. The aviation safe LED-based optical dazzler equipment (ASLODE) utilizes light emitting diode (LED) technology implemented with constant current regulators to control several modes of effects based on situational sensing. The temporarily incapacitating device can be extended by means of real-time illumination sensing to improve power efficiency and reach the highest level of safety. The smart pulse sets the flashing frequency from 8Hz for high-level light intensities and up to 20 Hz in low-level lighting conditions. Experimental results demonstrate the effectiveness of the ASLODE device over numerous experiments with controlled onboard aircraft scenarios that adapt the energy, flash rate, and processing to the sensed environmental illumination to meet aviation hygienic standards for people without eyesight defects.

Action potentials of single perigeniculate (PGN) cells and relay cells of the dorsal lateral geniculate nucleus (dLGN) with topographically matched or at least partially overlapping receptive fields (RF) were simultaneously recorded in the anesthetized and paralyzed cat during visual stimulation with moving gratings or flashing light spots of different size. In many cases, PGN cells showed an activity pattern which appeared like a mirror image of distinct periods of dLGN activity. Flashing spots evoked transient volleys of activity in PGN cells which increased in strength and shortened in latency with increasing size of the stimulus. These responses were temporally matched with inhibitory phases in the early part of visual responses in the dLGN. The spatio-temporal properties of the RFs were established by reverse correlation of the spike activity with the spatially random presentation of bright and dark spots within an array of 20 × 20 positions. Anticorrelated firing patterns of such kind could also be elicited as interocular inhibition with stimulation of the perigeniculate RF in the nondominant eye. Inversely correlated changes in spontaneous and visually induced activity were also visible during spontaneous changes in EEG pattern. With increasing synchronization of the EEG (predominance of delta-waves) the strength of geniculate visual responses declined while maintained perigeniculate activity increased. A weakened interocular and monocular inhibition of dLGN relay cells during visual stimulation of PGN RFs could be achieved with local reversible inactivation of PGN areas topographically matched with the dLGN recording sites. The results indicate that the PGN contributes to the state-dependent control of retino-geniculate transmission and to the monocular and interocular inhibitory processes that shape the visual responses in the dLGN.

Purpose – The purpose of this study is to develop a robotic training system for the hand movements during manual welding. The system provides real-time notice-feedback with sound or light alarms, whenever the welding hand vibrates beyond the nominal level observed with professional welders. Design/methodology/approach – The large variations of hand movements are detected by monitoring the deviation of the tool position from a smooth curve estimated in real time by a Kalman filter. An alarm is generated in the form of a flashing light or beep sound whenever the deviations exceed a predetermined threshold. The performance of hand movements is measured in terms of the variations of the position data. Twelve novice and five professional welders took part in the experiments and answered a questionnaire that assessed the usability and work load of the system. Findings – Compared to the sound alarms, the light alarms resulted in a larger and statistically significant decrease in the variation of hand movements of the novice welders and brought the level of variation close to that of the professional welders. The alarms did not result in a significant decrease in the variation of hand movements of the professional welders. The responses to the questionnaire indicated that both professional and novice welders found the system useful and they did not experience any significant work load. Social implications – The system developed in this study can ease the training of novice welders, by speeding up the learning and reducing the need for human tutors. Originality/value – This study is first to provide real-time notice-feedback for training while manual welding, based on a comparison of the performances of novice and professional welders.

The aim of the study is to optimize the conditions for in vitro cultivation of blue honeysuckle, raspberry and strawberry. The work was carried out in 2012-2020. The Murasige-Skuga medium (1/2 MS) was the control for all cultures for the initiation of explants. Additionally, we used a modified nutrient medium 1/2 MS with a reduced NH4 content by 15 % compared to the base MS; and Woodi Plant Medium (1/2 WPM) for honeysuckle; for raspberries - Quoirin-Lepoivre (1/2 QL) and 1/2 Anderson; for strawberries - 1/2 MS. For micropropagation and rooting, the following media were used: honeysuckle - modified MS and WPM; raspberries - QL and Anderson; strawberries - MS modified by Siliplant and Boksyu; control for all - MS. The following growth regulators were added to the optimal each culture a nutrient medium: 6-benzylaminopurine (6-BAP), gibberellic acid (GA), waste products of the large wax moth larvae, indolyl-3-butyric acid (IBA), Siliplant, EcoFus, HB-101. The effect of LED-phytoirradiators with a combination of red, blue and white light in the spectrum 2: 1: 1, 1: 1: 1, 2: 1, respectively, and LED-irradiators with a changing spectrum and flashing were studied at the stages of micropropagation and rooting in all cultures. The survival rate of honeysuckle explants on 1/2 WPM medium was 62.2 % (control 27.9 %). The highest reproduction factor of 5.1 (control 2.6) was achieved when using LED 2 red : 1 blue : 1 white on MS modified + 6-BAP 1.0 mg/L + kinetin 0.5 mg/L, and high rooting rate of honeysuckle 89.0 % (76.0 % k) was achieved on MS modified + IBA 0.5 mg/L. Cultivation of red raspberries on QL + 6-BAP 1.0 mg/L + GA 0.5 mg/L and LED irradiation 2 red : 1 blue : 1 white provided a reproduction factor of 5.3 (control 2.7), addition of IBA 0.5 mg/L + HB-101 100 μL/L in QL and LED irradiation 1 red : 1 blue : 1 white contributed to 100 % rooting. The addition of 6-BAP 1.0 mg/L + IBA 0.2 mg/L + GA 0.5 mg/L in QL and LED lighting 1 red : 1 blue : 1 white increased the reproduction factor of remontant raspberries by 1.6 times (from 2, 6 to 4.1), and the use of QL + IBA 0.5 mg/L + HB-101 50 μL/L and LED 2 red : 1 blue : 1 white increased its rooting ability to 96 % (control 67 %). LED irradiation with a changing spectrum during cultivation of garden strawberries on MS + Siliplant + EcoFus at 0.5 ml/L provided a reproduction factor of 5.9 (control 3.8), and the reproduction factor of remontant strawberries on MS + HB-101 100 μl/L was 7.4 (control 5.6). The addition of IBA 0.5 mg/L + HB-101 100 μL/L to the MS promoted the rooting of garden strawberries of 100 % when using a LED irradiator with a changing spectrum, and remontant strawberries – with a blinking LED irradiator

The effects of prior exposure to slow or fast temporal frequencies of visual or auditory stimuli on subsequent preferences for visual temporal frequencies were examined in three groups of neonates (N =12 in each group). The 2 Hz group was exposed to lights flashing at 2 Hz prior to half the preference trials and sounds pulsing at 2 Hz prior to the other half of the preference trials. The 8 Hz group was similarly prestimulated with 8 Hz lights and sounds. The control group received no prestimulation prior to preference trials. Preference trials consisted of the presentation of all possible pairs of 2, 4, or 8 Hz flashing lights for 20 sec per pair. Regardless of modality, visual preferences varied systematically with changes in prior stimulation such that there was an inverse relationship between amount of prestimulation and preferred temporal frequency. Infants looked more at slower frequencies and less at faster frequencies as the amount of prestimulation increased from none to 2 Hz to 8 Hz. These effects are similar to those found when internal stimulation is increased by testing neonates before feeding while unswaddled. Thus, we conclude that additional stimulation, whether from external or internal sources, influences neonates' visual attention through general rather than stimulus-specific effects on arousal.

The purpose of the subject is to design a car based on 51 single chip microcomputer control of nuclear intelligence toy car. Design is mainly divided into four modules respectively control module, test module, drive module, display module. Detection module by infrared receiving tube as tracking and obstacle avoidance of the detector to external environment for testing, testing mileage with hall element as the detector, test results of the test modules to control module, control module processed signal into the driver module to control the car turn left, turn right, forward, backward, at the same time control module and analysis processing state of marching into the 1602 LCD liquid crystal display status display. After many trials completed hardware design, the control core programming and sensor debug, finally realize the automatic tracking of toy cars, intelligent obstacle avoidance, mileage of display design requirements, and increase the car alarm, lights flashing remind and additional features such as voice control.

Electrical Energy is a very important need, but the electrical energy we use today still comes from conventional power plants that have negative threats such as pollution and fossil fuel reserves that are decreasing. To overcome this, by utilizing alternative energy that is environmentally friendly, one of them is wind energy and solar energy. Hybrid power plants use savonius helix wind turbines and solar cells are made to minimize the use of conventional energy. This tool utilizes wind and solar energy as the main media of electricity generation. The wind turbine which is made is a type of helix savonius vertical turbine that has a large torque, can rotate with low wind speed with a turbine size 80 cm high, diameter 25 cm which is connected to the generator and mounted on mechanical construction with a height of 200 cm and mounted control panel and solar cell with a capacity of 20 WP. This study aims to develop the potential of alternative energy as a power generation medium and be used as a source of flashing lights in the Indorama Engineering Polytechnic lightning tower tower. Savonius helix wind turbines that are designed require a minimum wind speed of 2.45 m / s for the start of the turbine rotation. Generating from the generator produces a maximum voltage of 18.64 V with a generator rotation of 304 rpm when not loaded and when loaded produces a maximum spin voltage of 281.3 rpm, 11.73 V voltage and 0.038 W power with a wind speed of 5 m/s. From the results of testing this hybrid power plant can be used for flashing lights on the lightning rod tower of the Indorama Polytechnic Engineering campus with a duration of 12 hours per day

Electrical Energy is a very important need, but the electrical energy we use today still comes from conventional power plants that have negative threats such as pollution and fossil fuel reserves that are decreasing. To overcome this, by utilizing alternative energy that is environmentally friendly, one of them is wind energy and solar energy. Hybrid power plants use savonius helix wind turbines and solar cells are made to minimize the use of conventional energy. This tool utilizes wind and solar energy as the main media of electricity generation. The wind turbine which is made is a type of helix savonius vertical turbine that has a large torque, can rotate with low wind speed with a turbine size 80 cm high, diameter 25 cm which is connected to the generator and mounted on mechanical construction with a height of 200 cm and mounted control panel and solar cell with a capacity of 20 WP. This study aims to develop the potential of alternative energy as a power generation medium and be used as a source of flashing lights in the Indorama Engineering Polytechnic lightning tower tower. Savonius helix wind turbines that are designed require a minimum wind speed of 2.45 m / s for the start of the turbine rotation. Generating from the generator produces a maximum voltage of 18.64 V with a generator rotation of 304 rpm when not loaded and when loaded produces a maximum spin voltage of 281.3 rpm, 11.73 V voltage and 0.038 W power with a wind speed of 5 m/s. From the results of testing this hybrid power plant can be used for flashing lights on the lightning rod tower of the Indorama Polytechnic Engineering campus with a duration of 12 hours per day.

This article argues that the mid-1960s saw a dramatic shift in how ‘brainwashing’ was popularly imagined, reflecting Anglo-American developments in the sciences of mind as well as shifts in mass media culture. The 1965 British film The Ipcress File (dir. Sidney J. Furie, starr. Michael Caine) provides a rich case for exploring these interconnections between mind control, mind science and media, as it exemplifies the era’s innovations for depicting ‘brainwashing’ on screen: the film’s protagonist is subjected to flashing lights and electronic music, pulsating to the ‘rhythm of brainwaves’. This article describes the making of The Ipcress File’s brainwashing sequence and shows how its quest for cinematic spectacle drew on developments in cybernetic science, multimedia design and modernist architecture (developments that were also influencing the 1960s psychedelic counter-culture). I argue that often interposed between the disparate endeavours of 1960s mind control, psychological science and media was a vision of the human mind as a ‘cybernetic spectator’: a subject who scrutinizes how media and other demands on her sensory perception can affect consciousness, and seeks to consciously participate in this mental conditioning and guide its effects.

AbstractLimitations of access have long restricted exploration and investigation of the cavities beneath ice shelves to a small number of drillholes. Studies of sea-ice underwater morphology are limited largely to scientific utilization of submarines. Remotely operated vehicles, tethered to a mother ship by umbilical cable, have been deployed to investigate tidewater-glacier and ice-shelf margins, but their range is often restricted. The development of free-flying autonomous underwater vehicles (AUVs) with ranges of tens to hundreds of kilometres enables extensive missions to take place beneath sea ice and floating ice shelves. Autosub2 is a 3600 kg, 6.7 m long AUV, with a 1600 m operating depth and range of 400 km, based on the earlier Autosub1 which had a 500 m depth limit. A single direct-drive d.c. motor and five-bladed propeller produce speeds of 1–2 m s−1. Rear-mounted rudder and stern-plane control yaw, pitch and depth. The vehicle has three sections. The front and rear sections are free-flooding, built around aluminium extrusion space-frames covered with glass-fibre reinforced plastic panels. The central section has a set of carbon-fibre reinforced plastic pressure vessels. Four tubes contain batteries powering the vehicle. The other three house vehicle-control systems and sensors. The rear section houses subsystems for navigation, control actuation and propulsion and scientific sensors (e.g. digital camera, upward-looking 300 kHz acoustic Doppler current profiler, 200 kHz multibeam receiver). The front section contains forward-looking collision sensor, emergency abort, the homing systems, Argos satellite data and location transmitters and flashing lights for relocation as well as science sensors (e.g. twin conductivity–temperature–depth instruments, multibeam transmitter, sub-bottom profiler, AquaLab water sampler). Payload restrictions mean that a subset of scientific instruments is actually in place on any given dive. The scientific instruments carried on Autosub are described and examples of observational data collected from each sensor in Arctic or Antarctic waters are given (e.g. of roughness at the underside of floating ice shelves and sea ice).

Packaging is not a complementary of the product. Packaging is an interface between producer and consumer in a supply chain. Portland cement is one of the products which is usually distributed in unit packed with bags made of kraft paper. Cement production that done with large capacity machines requires the amount of bag in quantity that much anyway. The production of bag factory in Cement company line 4 ideally could reach 9-10 million bags per month. In fact, the average production of cement bag from January to June 2012 is 6.5 million bags per month. In addition, the average defects of work in process in the range of the same month reached 56,000 tubes per month. This indicates that engine breakdown is happen frequently and there is a lack of good performance in term of production process quality control. Long reaction time of operator against the possible breakdown and the breakdown that occur is the cause of the length of time handling problems on the machine, so much going on a lot of waste in time and there are work in process defects that pass to the next process. Minimizing the reaction time to the breakdown of machine can be done with the implementation of jidoka system on the production floor. Andon which is the tool of jidoka will ensure operator and other parties (operators, technicians, foreman) gather to repair the machine effectively and also efficient in term of time. The lights that flashing and the sound of alarm that raised by andon will ensure this happen. Working procedures with the jidoka system approach is proven can minimize the reaction time to the breakdown of machine. Based on calculations, minimizing of time can reach up to 93.66%. The mathematical model for the jidoka system approach that has been valid then converted to a standard operating procedure in handling the breakdown of machine in bag factory. The standard operating procedure that proposed will be technically efficient and effective in terms of time and method to handle the breakdown of machine.

Introduction. Now, around the world, much attention is paid to an issue of timely receiving quality education. Training process always was and remains rather difficult type of work and demands from the pupil not only sufficient motivation, but also some other, not less important psychophysiological qualities of the personality. One of such obligatory qualities is presence at the studying health which is shown an optimum functional condition and high level of working capacity. Purpose. The research of influence of excessive pastime on the Internet on a functional condition and intellectual efficiency of second-year students of a bachelor degree of pedagogical higher education institution was the purpose of this work. Material and methods. Second-year students of a bachelor degree of pedagogical higher education institution, at the age of 19-20 years, daily carrying out more than 5 hours at the computer, from among which they were created control (n = 19) and experimental (n = 21), of group acted as examinees. To all respondents examination with assessment of initial level of the key psychophysiological indicators then respondents of experimental group observed a high security of work and rest was conducted. Results. After three-months realization of the studied elements of a healthy lifestyle at examinees of experimental group authentically significantly in comparison with reference values indicators the test health activity mood (for 29.0%), critical frequency of flashings (for 4.3%), difficult sensomotorny reaction to light (for 23.5%), operating with spatial representations and intelligence (by 25.9%), the strength of nervous processes and tests of Gencha improved (for 17.8%). Conclusion. Three-months observance of a rated work-rest schedule authentically significantly improves a functional condition and intellectual efficiency of second-year students of a bachelor degree of pedagogical higher education institution. However, the positive effect reached as a result of use of health saving behavior model gradually is lost on condition of return of examinees to initial behavioural concepts.

Reactive and proactive cognitive control are fundamental for guiding complex human behaviour. In two experiments, we evaluated the role of both types of cognitive control in navigational search. Participants searched for a single hidden target in a floor array where the salience at the search locations varied (flashing or static lights). An a-priori rule of the probable location of the target (either under a static or a flashing light) was provided at the start of each experiment. Both experiments demonstrated a bias towards rule-adherent locations. Search errors, measured as revisits, were more likely to occur under the flashing rule for searching flashing locations, regardless of the salience of target location in Experiment 1 and at rule-congruent (flashing) locations in Experiment 2. Consistent with dual mechanisms of control, rule-adherent search was explained by engaging proactive control to guide goal-maintained search behaviour and by engaging reactive control to avoid revisits to salient (flashing) locations. Experiment 2 provided direct evidence for dual mechanisms of control using a Dot Pattern Expectancy task to distinguish the dominant control mode for a participant. Participants with a reactive control mode generated more revisits to salient (flashing) locations. These data point to complementary roles for proactive and reactive control in guiding navigational search and propose a novel framework for interpreting navigational search.

Amphibian populations worldwide are currently in decline. One approach to preventing extinction of some of the affected species is to create assurance colonies. These sustainable populations might some day be used to reestablish wild populations. One issue with creating assurance colonies is successful breeding; often difficulties arise when attempting to breed exotic animals in zoological institutions. Sexual conditioning, a form of Pavlovian conditioning, has been shown to improve breeding behavior. In this study the efficacy of sexual conditioning to improve breeding behavior in the dyeing dart frog (Dendrobates tinctorius) was tested. Pairs of frogs were exposed to one of three conditions. In two conditions pairs were trained with a stimulus (a flashing green light) that was either predictive of (experimental) or independent of (active control) exposure to a member of the opposite sex. The third condition was a no-treatment control. After training all three conditions were given five days to interact. Members of the experimental condition showed shorter latencies to a variety of breeding behaviors and produced more eggs than those in the control conditions. The sexual conditioning procedure was successful in increasing breeding behavior in this population of frogs.

While it may seem that salient visual events, like the flashing lights on an ambulance, can automatically capture our attention, capture is actually under our control. Depending on our current internal goals, we adopt attentional control settings (ACSs) that specify what stimuli in the environment capture our attention. It has been shown that ACSs can be defined based on long-term episodic memory representations. For example, when searching for the items on your grocery list, an ACS can be specified based on your long-term memory of the list, such that your attention will be drawn to those items, and only those items. Importantly, episodic memories incorporate contextual information that can enhance recall when reinstated (e.g., you will remember your grocery list better if it was memorized at the grocery store rather than at home). Here we asked whether reinstating context can enhance the establishment of long-term memory ACSs. Participants memorized two sets of 15 images of objects in a particular context (i.e., a coloured box in a particular spatial location), that they then searched for, inducing an episodic-based ACS for those objects. During the search task, this encoding context was either reinstated, or not. We found that individuals are able to flexibly switch between ACSs and sources of information. However, we did not find sufficient evidence for the effect of context on the establishment of ACSs or their flexibility. This study extends our understanding of the factors that influence memory-guided attention, and the impact of contextual reinstatement on the formation of ACSs.

Background: Neurosarcoidosis manifests symptomatically in 5% of patients with sarcoidosis and diagnosis can be challenging if not clinically suspected. Cerebral mass-like presentation of neurosarcoidosis rarely reported in the literature. We presented a woman with neurosarcoidosis who had a cerebral mass-like lesion which completely disappeared after medical treatment. Discussion: A 37-year-old woman with history of pulmonary sarcoidosis referred to the emergency service of our hospital with a one-month history of progressive dizziness, nausea and seeing flashing lights. At neurologic examination, numbness and weakness on the left side of the body, deviation of uvula toward the right side was seen. Cranial MRI demonstrated a 2.5x2 cm in size mass lesion which hypointense on T1 WI, heterogeneous hyperintense on T2 and FLAIR sequence with peripheral vasogenic edema and heterogeneous, irregular contrast enhancement simulating brain tumor. Also, leptomeningeal and nodular contrast enhancement was seen on brainstem, cerebellar vermis, perimesencephalic cistern and left frontal, bilateral parietooccipital sulcus. In laboratory tests; The level of serum angiotensin-converting enzyme (ACE) was 53 IU/mL (N:8-52 IU/mL) and cerebrospinal fluid (CSF) ACE was 23 IU/mL (N:0-2.6 IU/mL). CSF cytology analysis was normal. Pattern 2 oligoclonal bands were present. With these clinical, laboratory and radiological findings, cerebral involvement of sarcoidosis was suspected. Biopsy was not performed due to the high risk of morbidity caused by the deep location of the lesion.Patient was treated with methylprednisolone and Azathioprine for a month.On post-treatment control imaging; lesion disappeared completely without residual leptomeningeal and nodular contrast enhancement.Also, neurologic symptoms were decreased remarkably. Conclusion: Multi-system inflammatory disorders like sarcoidosis, can present with mass-like lesion in the brain parenchyma. While early diagnosis is important to prevent unnecessary interventions like biopsy and surgery, it is crucial to initiate the necessary treatment with the aim of recovery without sequelae. Radiological and clinical follow-up are fundamental in differential diagnosis.

Find your black holes and white walls, know them … it is the only way you will be able to dismantle them and draw your lines of flight.—Deleuze and Guattari, A Thousand Plateaus Defined by originator David Belle as “an art to help you pass any obstacle”, the practice of “parkour” or “free running” constitutes both a mode of movement and a new way of interacting with the urban environment. Parkour was created by Belle (partly in collaboration with his childhood friend Sébastien Foucan) in France in the late 1980s. As seen in the following short video “Rush Hour”, a trailer for BBC One featuring Belle, parkour practitioners (known as “traceurs”), leap, spring, and vault from objects in the urban milieu that are intended to limit movement (walls, curbs, railings, fences) or that unintentionally hamper passage (lampposts, street signs, benches) through the space. “Rush Hour” was among the first media representations of parkour, and it had a significant role in introducing and popularizing the practice in Britain. Parkour has subsequently been widely disseminated via news reports, Nike and Toyota ads, the documentaries Jump London (2003) and Jump Britain (2005), and feature films, including Luc Besson’s Yamakasi – Les Samouraïs des Temps Modernes (2001) and Banlieu 13 (2004; just released in the U.S. as District B13), starring David Belle as Leto and Cyril Raffaelli as Damien. Sébastien Foucan will appear in the upcoming James Bond film Casino Royale as Mollaka, a terrorist who is chased (parkour-style) and then killed by Bond. (Foucan can also be seen in the film’s trailer, currently available at both SonyPictures.com and AOL.com; the film itself is scheduled for release in November 2006). Madonna’s current “Confessions” tour features an extended parkour sequence (accompanying the song “Jump”), albeit one limited to the confines of a scaffold erected over the stage. Perhaps most important in the rapid development of parkour into a world-wide youth movement, however, has been the proliferation of parkour websites featuring amateur videos, photos, tutorials, and blogs. The word “parkour” is derived from the French “parcours” (as the sport is known in France): a line, course, circuit, road, way or route, and the verb “parcourir”: to travel through, to run over or through, to traverse. As a physical discipline, parkour might be said to have a “poetics” — first, in general, in the Aristotelian sense of constructing through its various techniques (tekhnē) the drama of each parkour event. Secondly, one can consider parkour following Aristotle’s model of four-cause analysis as regards its specific materials (the body and the city), form or “vocabulary” of movements (drawn primarily from gymnastics, the martial arts, and modern dance), genre (as against, say, gymnastics), and purpose, including its effects upon its audience and the traceurs themselves. The existing literature on parkour (at this point, mostly news reports or websites) tends to emphasize the elements of form or movement, such as parkour’s various climbs, leaps, vaults, and drops, and the question of genre, particularly the ongoing, heated disputes among traceurs as to what is or is not true parkour. By contrast, my argument in this essay will focus principally on the materials and purpose of parkour: on the nature of the city and the body as they relate to parkour, and on the ways in which parkour can be seen to “remap” urban space and to demonstrate a resistance to its disciplinary functions, particularly as manifest in the urban street “grid.” The institution of the street “grid” (or variations upon it such as Haussmann’s Parisian star-configuration) facilitates both the intelligibility — in terms of both navigation and surveillance — and control of space in the city. It situates people in urban spaces in determinate ways and channels the flow of pedestrian and vehicular traffic. The “grid” thus carries a number of normalizing and disciplinary functions, creating in effect what the philosophers Gilles Deleuze and Félix Guattari refer to as a “striation” of urban space. This striation constitutes “a process of capture of flows of all kinds, populations, commodities or commerce, money or capital, etc.” within a field of determinate spatial coordinates (Deleuze and Guattari 386). It establishes “fixed paths in well-defined directions, which restrict speed, regulate circulation, relativize movement, and measure in detail the relative movements of subjects and objects” (Deleuze and Guattari 386). Many of these aspects of striation can be seen in the ways urban space is depicted in the “Rush Hour” video: in the gridlocked traffic, the flashing tail-lights, the “STOP” light and “WAIT” sign, the sign indicating the proper directional flow of traffic, and the grim, bundled-up pedestrians trudging home en masse along the congested streets. Against these images of conformity, regulation, and confinement, the video presents the parkour ethos of originality, “reach,” escape, and freedom. Belle’s (shirtless) aerial traversal of the urban space between his office and his flat — a swift, improvisational flow across the open rooftops (and the voids between them), off walls, and finally down the sloping roof into his apartment window — cuts across the striated space of the streets below and positions him, for that time, beyond the constrictions of the social realm and its “concrete” manifestations. Though parkour necessarily involves obstacles that must be “overcome,” the goal of parkour is to do this as smoothly and efficiently as possible, or, in the language of its practitioners, for the movement to be “fluid like water.” The experience of parkour might, then, be said to transform the urban landscape into “smooth space,” in Deleuze and Guattari’s sense of “a field without conduits or channels” (371), and thus into a space of uninhibited movement, at least in certain ideal moments. Parkour seems to trace a path of desire (even if the desire is simply to avoid the crowds and get home in time to watch BBC One) that moves along a Deleuzean “line of flight,” a potential avenue of escape from the forces of striation and repression. Here the body is propelled over or through (most parkour movement actually takes place at ground level) the strata of urban space, perhaps with the hope that, as Deleuze and Guattari suggest, “one will bolster oneself directly on a line of flight enabling one to blow apart strata, cut roots, and make new connections” (15). In the process, parkour becomes “an art of displacement,” appropriating urban space in ways that temporarily disrupt their controlling logics and even imply the possibility of a smooth space of desire. One might see parkour as an overcoming of social space (and its various constrictions and inhibitions of desire, its “stop” and “wait” signs) through the interplay of body and material barriers. The body becomes an instrument of freedom. This, again, is graphically conveyed in “Rush Hour” through the opening scene in which Belle strips off his business suit and through the subsequent repeated contrasts of his limber, revealed body to the rigid, swathed figures of the pedestrians below. In part an effect of the various camera angles from which it is shot, there is also an element of the “heroic” in this depiction of the body. This aspect of the representation appears to be knowingly acknowledged in the video’s opening sequence. The first frame is a close-up, tightly focused on a model of a ninja-like figure with a Japanese sword who first appears to be contemplating a building (with an out-of-focus Belle in the background contemplating it from the opposite direction), but then, in the next, full shot, is revealed to be scaling it — in the manner of superheroes and King Kong. The model remains in the frame as Belle undresses (inevitably evoking images of Clark Kent stripping down to his Superman costume) and, in the final shot of that sequence, the figure mirrors Belle’s as he climbs through the window and ascends the building wall outside. In the next sequence, Belle executes a breath-taking handstand on a guard railing on the edge of the roof with the panorama of the city behind him, his upper body spanning the space from the street to the edge of the city skyline, his lower body set against the darkening sky. Through the practice of parkour, the relation between body and space is made dynamic, two reality principles in concert, interacting amid a suspension of the social strata. One might even say that the urban space is re-embodied — its rigid strata effectively “liquified.” In Jump London, the traceur Jerome Ben Aoues speaks of a Zen-like “harmony between you and the obstacle,” an idealization of what is sometimes described as a state of “flow,” a seemingly effortless immersion in an activity with a concomitant loss of self-consciousness. It suggests a different way of knowing the city, a knowledge of experience as opposed to abstract knowledge: parkour is, Jaclyn Law argues, “about curiosity and seeing possibilities — looking at a lamppost or bus shelter as an extension of the sidewalk” (np.). “You just have to look,” Sébastien Foucan insists in Jump London, “you just have to think like children….” Parkour effectively remaps urban space, creating a parallel, “ludic” city, a city of movement and free play within and against the city of obstacles and inhibitions. It reminds us that, in the words of the philosopher of urban space Henri Lefebvre, “the space of play has coexisted and still coexists with spaces of exchange and circulation, political space and cultural space” (172). Parkour tells us that in order to enter this space of play, we only need to make the leap. References Deleuze, Gilles and Félix Guattari. A Thousand Plateaus: Capitalism and Schizophrenia. Trans. Brian Massumi. Minneapolis: University of Minnesota Press, 1987. Jump London (2003). Mike Christie, director. Mike Smith, producer. Featuring Jerome Ben Aoues, Sébastien Foucan, and Johann Vigroux. Law, Jaclyn. “PK and Fly.” This Magazine May/June 2005 http://www.thismagazine.ca/issues/2005/05/>. Lefebvre, Henri. “Perspective or Prospective?” Writings on Cities. Trans. Eleonore Kofman and Elizabeth Lebas. Oxford: Blackwell, 1996. Rush Hour (2002). BBC One promotion trailer. Tom Carty, dir. Edel Erickson, pro. Produced by BBC Broadcast. See also: Wikipedia on parkour: http://www.en.wikipedia.org/wiki/Parkour> Parkour Worldwide Association: http://www.pawa.fr/> Parkour Net (multilingual): http://parkour.net/> NYParkour: http://www.nyparkour.com/> PKLondon.com: http://www.pklondon.com/> Nike’s “The Angry Chicken” (featuring Sébastien Foucan): http://video.google.com/videoplay? docid=-6571575392378784144&q=nike+chicken> There is an extensive collection of parkour videos available at YouTube A rehearsal clip featuring Sébastien Foucan coaching the dancers for Madonna’s Confessions tour can be seen at YouTube Citation reference for this article MLA Style Geyh, Paula. "Urban Free Flow: A Poetics of Parkour." M/C Journal 9.3 (2006). echo date('d M. Y'); ?> <http://journal.media-culture.org.au/0607/06-geyh.php>. APA Style Geyh, P. (Jul. 2006) "Urban Free Flow: A Poetics of Parkour," M/C Journal, 9(3). Retrieved echo date('d M. Y'); ?> from <http://journal.media-culture.org.au/0607/06-geyh.php>.