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When I started fieldwork among the Maka in SE Cameroon in 1971 I was suprised that for them kinship was hardly about ascribing people a fixed position. In retrospect this makes me realize how deeply Talcott Parsons’ famous pattern variables – notably ‘ascription’ versus ‘achievement’ influenced our perspective. But Maka people turned out to be true masters in ‘working’-with kinship, constantly ‘discovering’ kin in unexpected contexts, making creative equations and switch-es. My subsequent research in the area (up till now) highlighted how over time this plasticity of their kinship arrangements increased with growing urbanization and even more with transcontinental migration. Cameroon’s famous ‘bush-fallers’ have developed their own ways for ‘working’ with kinship. However, this plasticity should not only be studied as stemming from new and shifting conditions. I hope to show as well that such a more dynamic view on kinship is valuable for re-evaluating classical kinship theory.

The paper present the result of the study on the use of simulation software of ANSYS R15.0 version in attempt to simulate the load which is working on a screwed shaft of a shaping machine. This shaft was broken down during normal working and within limit of its life time. Therefore, the simulation would try to find out the cause of the failure. In order to simulate the load, the mechanical properties and chemical composition of the shaft were used as the input for modeling. The shaft is made of medium carbon steel of S 45 C in round shape. The finite element method (FEM) was used for analyzing. The modeling was started with a 3D redrafting the real dimension of the shaft in a computer aided design (CAD) model, then imported to the ANSYS system into FEM format. The mechanical and physical properties of the material was entered as the engineering data. Meshing was made to divide the component into several small elements. A combination of static and torsion load was applied to the shaft with a fixed position. The simulation results shown that von mises stress of 4.546 MPa was achieved. While, the first principal stress of 4.518 MPa, the third principal stress of 0.538 MPa. Other result revealed that the displacement was 0.001602 mm. Simulation also indicate that failure occurs at the slot a place where the pin was inserted to lock between the shaft and the bevel gear. The result is in accordance with the real failure of the shaft. To conclude, the ANSYS with FEM modeling has succeeded to simulate the failure of the screwed shaft.

This study aimed to investigate the wear failure changes of spindle hook teeth and the reasons for such failure during field work. Spindle samples were obtained from a fixed position of the spindle bar under different field picking area conditions and combined with the spatial distribution characteristics of cotton bolls in Xinjiang. After cutting a spindle sample, a scanning electron microscope and an energy spectrum analyzer were used to characterize the micromorphology and element composition of the hook tooth surface and cross section under different working area conditions. The wear parameters of the hook teeth were then extracted. The results showed that the thickness of the coating on the surface of the hook tooth used in this study was between 66.1 µm and 74.4 µm. The major chemical element was chromium, with a small amount of nickel. During the field picking process, failure of the coating on the surface of the hook teeth initially appeared on the tooth tip and tooth edge, and then spread to the entire hook tooth surface. The wear failure of the hook teeth resulted from abrasive wear, oxidative wear, and fatigue peeling. As the picking area increased, the wear area of the hook teeth increased exponentially, while the wear width increased linearly. When the field picking area reached 533.33 ha, the maximum change rate of the wear area was 2.33 × 103 µm2/ha, and the wear width was 1.84 µm/ha. During field work, the thickness of the coating decreased from the cutting surface to the tooth edge, and the wear rate gradually increased. The wear rate at Position 1 was the slowest, at 0.01 µm/ha, and the wear rate at Position 5 was the fastest, at 0.25 µm/ha.

Background Against a backdrop of declining tobacco use, e-cigarette markets are growing. The UK now has a higher percentage of e-cigarette users than any other European country. These developments have prompted fierce discussions in scientific, advocacy and policy communities about how best to respond. This article is one of the first to examine the role of evidence in these debates. Methods We analysed 121 submissions to two Scottish policy consultations on e-cigarettes (in 2014 and 2015) and undertook interviews with 26 key informants in 2015–2016, following up with a sub-set in 2019–2020. All data were thematically coded, and our analysis was informed by insights from policy studies and the sociology of science. Results First, we affirm previous research in suggesting that e-cigarettes appeared to have triggered a breakdown of old public health alliances. Second, we demonstrate that, amid concerns about research quality and quantity, actors are guided by normative outlooks (and/or economic interests) in their assessments of evidence. Third, we show that, despite describing e-cigarette debates as contentious and polarised, actors engaging in Scottish policy debates exhibit a spectrum of views, with most interviewees occupying an uncertain ‘middle ground’ that is responsive to new evidence. Fourth, we suggest that the perceived divisiveness of e-cigarette debates is attributed to recurrent media simplifications and tensions arising from the behaviours of some actors with settled positions working to promote particular policy responses (including by strategically enrolling supportive evidence). Fifth, we argue that the actions of these actors are potentially explained by the prospect that e-cigarettes could usher in a new tobacco ‘policy paradigm’. Finally, we show how scientific authority is employed as a tool within these debates. Conclusions E-cigarette debates are likely to reconcile only if a clear majority of participants in the uncertain ‘middle ground’ settle on a more fixed position. Our results suggest that many participants in Scottish e-cigarette debates occupy this ‘middle ground’ and express concerns that can be empirically assessed, implying evidence has the potential to play a more important role in settling e-cigarette debates than previous research suggests.

International audience; When a disaster occurs, during a long period of time people suffer to have no means to communicate with their relatives. The presented work aims at proposing a solution composed of a ground station located nearby the damaged area coupled with a swarm of drones. The ground station plays the role of a gateway between cellular networks, that are still up but out of reach of people, with drones that carry messages from and to people located in the disastered region. We analyze the possibility of deploying drones with fixed positions and a more flexible solution allowing drones to move but at the cost of intermittent communications, allowing only sms-like messages. We show that using the same number of drones, allowing drones to move improves dramatically the coverage of people with respect to a FANET in which drones stay at a fixed position. We also show that even for a very restricted number of drones, for reasonable communication ranges, almost all the people benefit from an important average connected time.

Assembly stations are important hubs that connect massive material, information, human labor, etc. The fixed-position assembly systems for complex products may deal with hundreds of thousands of processes, making them vulnerable to manufacturing exceptions. Many scheduling problems were described and solved in the past decades, however, the gap between theoretical models and industrial practices still exist. To achieve a practical method for the dynamic scheduling in case of exceptions while reducing the impact brought by the exceptions, an Intelligent Collaborative Mechanism (ICM) was proposed where negotiations on resource configuration may happen among tasks (i.e. assembly processes). The intercommunication among resources was guaranteed by the data-driven ICM framework. The Petri-net-based workflow analysis and the constraint matrix can pick out the tasks that are currently not bound by other ones. The dynamic priority of the processes was defined and obtained using grey relational analysis. The matching strategy among the selected tasks and operators can provide a scheduling plan that is close to the initial plan, so the assembly systems may remain effective even when exceptions occur. The proposed models were analyzed in a case scenario, where the impact brought by exceptions can decrease by 44.3% in terms of the operators’ utilization rate, and by 60.26% in terms of the assembly time. This research has provided a practical strategy to improve the flexibility and effectiveness of assembly systems for complex products.

Purpose Pterygia are much more common nasally than temporally. Ultraviolet (UV) radiation is a major risk factor. Coroneo proposed that the nasal preference is caused by the "peripheral light focusing effect," (PLF), in which UV at an oblique angle passes through temporal cornea and is concentrated on and damages nasal limbal stem cells. This study evaluates whether the PLF is sufficient to explain the nasal preference. Methods Whereas Coroneo and colleagues derived the maximum PLF intensity gain (UV concentration factor) as a function of incident angle (i.e., different nasal limbal positions were used for different incident angles) the current analysis derived intensity gain at a fixed position such at the nasal corneo-limbal junction (CLJ). This provided a measure of the total PLF irradiation at this position, which was compared to total direct irradiation of nasal and temporal limbus at the corresponding positions (e.g., CLJs). In Part 1, analysis was performed like that of Coroneo, using horizontally incident UV; in Part 2, the analysis was extended to include incident rays above and below the horizontal. Results In both part 1 and part 2 of the study, the limbal UV irradiation of the nasal limbus from the PLF was not sufficient to explain the strong nasal location preference of pterygia. Conclusions The analysis calls into question the PLF explanation of nasal location preference. Other explanations of the nasal preference, and of pterygium pathogenesis, should be considered, such as temporal to nasal tear flow carrying substances such as cytokines to the nasal limbus.

Immersive content has become a popular medium for storytelling. This type of content is typically accessed via a head-mounted visual display within which the viewer is located at the center of the action with the freedom to look around and explore the scene. The criteria for subtitle position for immersive media still need to be defined. Guiding mechanisms are necessary for circumstances in which the speakers are not visible and viewers, lacking an audio cue, require visual information to guide them through the virtual scene. The aim of this reception study is to compare different subtitling strategies: always-visible position to fixed-position and arrows to radar. To do this, feedback on preferences, immersion (using the IPQ questionnaire) and head movements was gathered from 40 participants (20 hearing and 20 hard of hearing). Results show that always-visible subtitles with arrows are the preferred option. Always-visible and arrows achieved higher scores in the IPQ questionnaire than fixed-position and radar. Head-movement patterns show that participants move more freely when the subtitles are always-visible than when they are in a fixed position, meaning that with always-visible subtitles the experience is more realistic, because the viewers do not feel constrained by the implementation of subtitles. Resumen Los contenidos inmersivos se han convertido en un medio interesante para contar historias. A este tipo de contenido normalmente se accede con unas gafas de realidad virtual, a través de las cuales el usuario, que se encuentra en el centro de la acción, tiene la libertad de mirar y explorar la escena libremente. Los criterios para determinar la posición de los subtítulos en contenidos inmersivos todavía no se han definido. También se necesitan mecanismos de guía para indicar dónde está la persona que habla cuando está fuera del campo de visión y los usuarios no pueden contar con el audio para guiarse. El objetivo de este estudio de recepción es comparar diferentes estrategias de subtitulación: subtítulos siempre visibles con subtítulos colocados en posiciones fijas, y flechas con radar. Para ello, se han recopilado los comentarios de 40 participantes (20 oyentes y 20 con pérdida auditiva) sobre las preferencias, la inmersión (con el cuestionario IPQ) y los patrones de movimiento de cabeza. Los resultados muestran que los subtítulos siempre visibles con flechas son la opción preferida. Además, estas soluciones obtuvieron mejores puntuaciones en el cuestionario IPQ. Los patrones de movimientos de cabeza muestran que los participantes se movían más libremente con los subtítulos siempre visibles, lo que supone que con este tipo de subtítulos la experiencia es más realista ya que los usuarios no se sienten cohibidos por la integración de los subtítulos. Résumé Les contenus immersifs sont devenus un moyen intéressant de raconter des histoires. Ce type de contenu est généralement accessible avec des lunettes de réalité virtuelle, avec lesquelles l’utilisateur est au cœur de l’action et à la liberté de regarder et d’explorer la scène librement. Les critères pour définir la position des sous-titres dans ce contenu n’a pas encore été définie. Des mécanismes de guidage sont également nécessaires pour indiquer où se trouve le locuteur lorsqu’il est hors du champ de vision et que les utilisateurs ne peuvent pas se fier à l’audio pour être guidés. L’objectif de cette étude de réception est de comparer différentes stratégies de sous-titrage : des sous-titres toujours visibles avec des sous-titres placés à des positions fixes et des flèches avec le radar. À cet égard, les commentaires de 40 participants (20 auditeurs et 20 malentendants) ont été recueillis sur les préférences, l’immersion (avec le questionnaire IPQ) et les schémas de mouvements de la tête. Les résultats montrent que les sous-titres qui sont toujours visibles avec des flèches sont l’option préférée. En outre, ces solutions ont obtenu de meilleurs résultats dans le questionnaire IPQ. Les modèles de mouvements de la tête montrent que les participants se sont déplacés plus librement avec les sous-titres toujours visibles, ce qui signifie qu’avec ce type de sous-titres, l’expérience est plus réaliste car les utilisateurs ne sont pas gênés par l’intégration des sous-titres.

Systems engineering of a satellite based data communication baseline concept is presented to achieve terabit per second throughput. It uses a constellation of five Molniya satellites and one dimension electronic scanning phased array ground terminals. The result is a baseline concept that meets customer needs for internet of things (IoT) data connectivity and for consumer high data rate internet access. Molniya orbit satellites provide the benefits of available bandwidth, lack of interference with other satellite links, and less crowded orbital paths. A drawback is that they are not geostationary since they have highly elliptical orbits. This requires ground station terminals with the ability track the satellites as they pass overhead during their orbit. However, since Molniya satellites with a properly selected eccentricity pass along the same path at nearly constant elevations relative to a fixed position on the Earth, simple and low-cost single axis scanning antennas can be used for the consumer ground terminal. This is a distinct advantage compared with competing low earth orbit constellations. The proposed solution leverages advances in semiconductor technology and low-cost antenna laminate substrate materials for an affordable phased array tracking ground terminal antenna. This paper presents link budget trade studies, system concept, orbital dynamics simulation results, and ground station component trade study.

Photoembossing is a cost-effective technique for the production of complex surface relief structures in a photopolymer film, achieved via contact-mask exposure to UV-light. Here, photoembossing is explored using interference holography with a CW laser and a nanosecond pulsed laser. It is shown that identical surface relief structures are produced if the photopolymer film is kept in a fixed position. In the case of a moving substrate, relief structures are only obtained with the pulsed laser and the heights of the relief structures and their shape are the same as in the static experiments. This illustrates that photoembossing in combination with pulsed laser interference holography is potentially useful in the production of large area structured films using roll-to-roll processes., This work was also partly supported by the Spanish MINECO project MAT2011-27978-C02-02, the ARAID project for Young Researchers, the CSIC project i-LINK0394, Gobierno de Aragón and FEDER funding (EU).

Purpose. Various parameters can influence temperature rise and detection during implant site preparation. The aim of this study is to investigate local temperature values in cortical and corticocancellous bovine bone during early stages of piezoelectric implant site preparation.Materials and Methods. 20 osteotomies were performed using a diamond tip (IM1s, Mectron Medical Technology, Carasco, Italy) on two different types of bovine bone samples, cortical and corticocancellous, respectively. A standardized protocol was designed to provide constant working conditions. Temperatures were measured in real time at a fixed position by a fiber optic thermometer.Results. Significantly higher drilling time (154.90 sec versus 99.00 sec;p<0.0001) and temperatures (39.26°C versus 34.73°C;p=0.043) were observed in the cortical group compared to the corticocancellous group. A remarkable variability of results characterized the corticocancellous blocks as compared to the blocks of pure cortical bone.Conclusion. Bone samples can influence heat generation duringin vitroimplant site preparation. When compared to cortical bone, corticocancellous samples present more variability in temperature values. Even controlling most experimental factors, the impact of bone samples still remains one of the main causes of temperature variability.

Human consumption of bird meat in modern societies comes in two ways: as embryos -i.e., eggs- and as hatched individuals, either young or adults. Poultry provide nowadays about one-third of the animal proteins and fat in human diets, but the bird-human interface is possibly an ancient one. Hundreds of species are kept as pets and non-edible products, such as feathers or eggshells are used by traditional cultures in all continents as body ornaments, headdresses or jewelry. Regarding early humans, it has been proposed that Neanderthals decorated themselves with raptors and corvid feathers. It is also known that they consumed birds, including pigeons, according to cut marks in bone remains. Even if birds may be perceived as elusive prey due to their flight capabilities, they are forced to incubate their eggs in a fixed position, the nest, where the nestlings grow until they reach full size. This makes eggs, nestlings and brooding adults easy prey. Roosting birds are practically defenseless against stealth predators. And humans may become such when they learn to interpret cues left behind by the birds themselves. Birds share a common sensitive world with humans. Most birds are diurnal as we are, and they rely on visual and auditive cues for communication, that we may learn to interpret, or that we can even imitate.

This paper addresses two issues, the categorial nature of (pronominal) clitics and the conditions ruling their surface distribution as proclitics and enclitics, which we take as related. We claim that pronominal clitics are defective functional heads consisting of a bundle of φ-features, and hence, that they are merged in a fixed position in the functional structure of the clause. The (micro)variation in clitic order patterns will be accounted for through the interplay of verb movement and the Proclisis Parameter: when languages set the value ‘yes’ for this parameter, proclisis is the dominant pattern, whereas in languages setting the value ‘no’ for the same parameter, enclisis dominantly occurs; other differences between Romance languages and, in particular, EP and BP, are accounted for by the properties of the nodes T and Asp, namely, their ability to attract V and or to check uninterpretable features through Agree without Attract.

Giovanni Pico della Mirandola (1463-1494) focuses on Anaxagoras (ca. 500-428 BC) because he considers him as a precursor of the the later Neoplatonic concept all things exist in all things in their own mode, which became the core of Pico’s metaphysics. Anaxagoras’s philosophy permits Pico to establish his doctrine that all things share a portion of God within them, in their own way. Pico rejects the fixed position of man in the ontological hierarchy. Man has the chance to become everything. Pico asserts that man contains all things in himself as their center, just like God contains all things as their origin. As a consequence, Anaxagoras’s principle is supportive to Pico’s metaphysics. Furthermore, Anaxagoras’s metaphysical principle is supportive of Pico’s method of allegorical interpretation, which is indispensable for his syncretism and his attempt to reveal hidden truths in every text or level of reality.

Objective: Robotic surgical systems offer better workplace in order to relieve surgeons from prolonged physical efforts and improve their surgical outcomes. However, robotic surgery could produce musculoskeletal disorders due to the prolonged sitting position of the operator, the fixed position of the console viewer and the movements of the limbs. Until today, no one study has been reported concerning the association between robotics and musculoskeletal pain. The aim of this work was verify the prevalence of musculoskeletal disorders among Italian robotic surgeons. Material and methods: Between July 2011 and April 2012 a modified Standardized Nordic Questionnaire was delivered to thirty-nine Italian robotic centres. Twentytwo surgeons (56%) returned the questionnaires but only seventeen questionnaires (43.5%) were evaluable. Results: Seven surgeons (41.2%) reported musculoskeletal disorders, by since their first use of the robot which significantly persisted during the daily surgical activity (P < 0.001). Regarding the body parts affected, musculoskeletal disorders were mainly reported in the cervical spine (29.4%) and in the upper limbs (23.5%). Six surgeons (35.3%) defined the robotic console as less comfortable or neither comfortable/uncomfortable with a negative influence on their surgical procedures. Conclusions: In spite of some important limitations, our data showed musculoskeletal disorders due to posture discomfort with negative impact on daily surgical activity among robotic surgeons. These aspects could be due to the lack of ergonomic seat and to the fixed position of the console viewer which could have produced an inadequate spinal posture. The evaluation of these postural factors, in particular the development of an integrated and more ergonomic chair, could further improve the comfort feeling of the surgeon at the console and probably his surgical outcomes.

When a visual target briefly appears in a display containing visual motion information, the perceived position of the target is mislocalized forward along its direction of motion. This phenomenon is assumed to be caused by the interaction between the transient onset signal of the target and motion information. However, while transient onset and offset signals are important for the establishment of our perceptual awareness, it has not been examined whether transient offset signals could be also effective for target mislocalization. Here, we demonstrate that shifts in perceived position occurred for a visual target containing a temporally transient offset signal in an apparent motion (AM) display. First, with horizontal AM, we found that illusory motion was perceived when a static target transiently and repeatedly blinked at a fixed position. The perceived direction of the illusory motion was in counter-phase with that of the AM stimuli. Further, we confirmed that illusory motion was frequently perceived when (1) the eccentricity of the target was larger, (2) offset duration was longer, and (3) smoother AM was perceived. Illusory motion was not perceived unless AM stimuli were presented after the offset signal, while illusory motion still occurred when the AM stimuli disappeared before the offset signal. In addition, we found that mislocalization of the target’s perceived position actually occurred in a direction opposite to AM. These findings suggest that a transient offset signal could trigger perceptual mislocalization of static visual stimuli by interacting with motion information in a postidicitve manner.

The purpose of this paper is to resolve a confusion that may arise from two quite distinct definitions of “Doppler shifts”: both are used in the oceanographic literature but they are sometimes conflated. One refers to the difference in frequencies measured by two observers, one at a fixed position and one moving with the mean flow—here referred to as “quasi-Doppler shifts.” The other definition is the one used in physics, where the frequency measured by an observer is compared to that of the source. In the latter sense, Doppler shifts occur only if the source and observer move with respect to each other; a steady mean flow alone cannot create a Doppler shift. This paper rehashes the classical theory to straighten out some misconceptions. It is also discussed how wave dispersion affects the classical relations and their application.

5D cosmological model with 3-brane with matter is considered. The brane divides bulk in two AdS half spaces. Geometry of the model can be described by two types of coordinates: in the first setting the metric is static and the brane is moving in the bulk, in the second approach the metric is time-dependent and the brane is located at a fixed position in the bulk. Coordinate transformation connecting two coordinate systems is constructed., 7 pages

It has recently been shown that spatially uninformative sounds can cause a visual stimulus to pop-out from an array of similar distractor stimuli when that sound is presented near simultaneously with a feature change in the visual stimulus. Until now, this effect has only been shown for stimuli that remain at a fixed position. Here we extend these results by showing that auditory stimuli can also improve the detectability of visual stimulus features related to motion. To accomplish this we presented moving visual stimuli (small dots) on a computer screen. At a random moment during a trial, one of these stimuli could abruptly start moving in an orthogonal direction. Participants' task was to indicate whether such a change in direction had occurred or not by making a corresponding button press. When a sound (a short 1000Hz tone pip) was presented simultaneously with a motion change, participants were able to detect this motion direction change among a significantly higher number of distractor stimuli, compared to when the sound was absent. When the number of distractor stimuli was kept constant, detection accuracy was significantly higher when the tone was present, compared to when it was absent. Using signal detection theory, we determined that this change in accuracy was reflected in an increase in d“, while we found no evidence to suggest that participants' response bias (as reflected nearly equal beta parameters), changed due to the presence of the sounds.

The latitude effect has been studied by means of a shipboard neutron monitor during 12 passages of the so-called knee. The latter remained in a fixed position (46.0° ± 1.0° N, 7° W) between Oct. 1956 and Feb. 1959. Above the knee there exists a plateau due to the atmospheric attenuation of the nucleon component. The horizontal part of this plateau extends to a threshold rigidity of 3.2±0.5 GeV/c. DOI: 10.1111/j.2153-3490.1962.tb01348.x

International audience; This paper investigates new families of displaced, highly non-Keplerian orbits in the two-body problem and artificial equilibria in the circular restricted three-body problem. The families of orbits presented extend prior work by using periodic impulses to generate displaced orbits rather than continuous thrust. The new displaced orbits comprise a sequence of individual Keplerian arcs whose intersection is continuous in position, with discontinuities in velocity removed using impulses. For frequent impulses the new families of orbits approximate continuous thrust non-Keplerian orbits found in previous studies. To generate approximations to artificial equilibria in the circular restricted three-body problem, periodic impulses are used to generate a sequence of connected three-body arcs which begin and terminate at a fixed position in the rotating frame of reference. Again, these families of orbits reduce to the families of artificial equilibria found using continuous thrust.

The purpose of this experiment was to examine the effects of advance knowledge on the kinematics of one-handed catching. Balls were launched from a distance of 8.4 m by a ball-projection machine with adjustable launching speed. Fifteen skilled ball catchers caught 160 balls with their preferred hand under blocked-order (4 blocks, each comprising 20 trials at 1 of 4 different ball speeds) or random-order (4 blocks, each comprising 20 trials of 4 different ball speeds) conditions. By projecting balls with different ball speeds from a fixed position, it was possible to modify the temporal constraints of the catching task. In both the blocked-order and random-order conditions, catching performance (number of catches, touches and misses) decreased with increasing temporal constraints. Analysis of successful trials indicated that this equal level of catching performance was achieved with different movement kinematics. Specifically, there was a change in movement time, latency, wrist velocity profile, and coefficient of straightness. Based on expectancy of previous trials, movement kinematics was scaled to ball speed in the blocked-order condition whereas in the random-order condition, participants exhibited a more default initial response. However, this latter mode of control was functional in that it increased the likelihood of success for the higher ball speeds while also providing participants with a larger temporal window to negotiate the unexpected temporal constraint on-line for the lowest ball speed. © 2009 Springer-Verlag.

A static oven designed for French bread baking has been instrumented to monitor the processing conditions and record variables responsible for dough changes. Thermocouples are inserted at fixed position in the dough, mass loss is continuously weighed whereas expansion is measured by CCD video camera. Internal pressure and ambient humidity are controlled. Standard conditions for acceptable bread are checked and variable profiles measured in order to define the different sequences of variables related to the main macroscopic changes: expansion, scars opening and crust setting. This scheme is confirmed by modifying main operating conditions (temperatures and vapour injection), showing that water vapour favours expansion, reaching its maximum up to 1.7, at a crumb temperature close to 90 °C, in relation with internal pressure (90 kPa). Vault and hearth temperatures mainly influence crust, the setting of which stops loaf volume decrease (20%).

The Mach-Zehnder interferometer can be used as is customary in optical testing but, to examine different layers of a volume, the procedure of either readjusting the interferometer or displacing the specimen can be avoided, employing an incoherent periodic source. In this case, leaving the specimen in a fixed position and without readjusting the interferometer, the different layers can be analysed, shifting a non-classical localization plane by a change in the source period. In this paper experimental interferograms, obtained by varying this period to map the disturbances present on either one or both faces of a phase object, are shown. Fil: Simon, Juan Miguel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física. Laboratorio de Óptica; Argentina Fil: Comastri, Silvia Ana Elva. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física. Laboratorio de Óptica; Argentina Fil: Echarri, Rodolfo Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física. Laboratorio de Óptica; Argentina

In this study the effect of dynamic stimuli on low back pain during prolonged sitting was investigated. The pain experience of two groups of 60 subjects with a specific low back pain was recorded. All subjects were investigated on pain behaviour by the Multidimensional Pain Inventory (MPI) and pain was measured on an open visual analogue scale (VAS). During sitting, one group received dynamic stimuli that were generated by alternating rotations in the horizontal plane of the seat of the chair, with back and arm rests in fixed position. Two different frequencies of rotation were applied in subgroups. The authors concluded that such stimuli, especially of the lower frequency, reduced pain in prolonged sitting.

A cold model of a CFB, having a 0.120m ID, 5.75m high riser, was operated at a superficial gas velocity of 6m/s and at average solids mass fluxes varying in the range between 16 and 55kg/sm2. A stream of carbon dioxide was injected continuously at a fixed position along the riser axis and used as tracer gas. Three solids, belonging to groups A and B of Geldart's classification, were selected in order to investigate separately, the effect of particle size and density on the radial mixing of the gas phase. The intensity of radial gas dispersion reduced when larger or heavier particles were used. The differences in the values of radial dispersion coefficient and Peclet number were explained, taking into account the role of the particle size with respect to the scale of gas turbulence. On a fait fonctionner un modele froid de CFB, ayant un diametre interieur de 0,120 m et une colonne montante de 5,75 m de hauteur, a une vitesse de gaz superficielle de 6 m/s et a des flux massiques de solides moyens variant entre 16 et 55 kg/cm2. Un courant de gaz carbonique a ete injecte en continu a une position le long de l'axe de la colonne montant fixe et utilise comme gaz traceur. Trois solides, appartenant aux groupes A et B de la clasification de Geldart, ont ete selectionnes pour etudier separement l'effet de la taille et de la masse volumique des particules sur le melange radial de la phase gazeuse. L'intensite de la dispersion radiale du gaz diminue avec des particules plus grosses ou plus lourdes. On explique les differences dans les valeurs du coefficient de dispersion radiale et du nombre de Peclet en tenant compte du role de la taille des particules relativement a l'echelle de la turbulence du gaz.

In the Nagel-Schreckenberg model of vehicular traffic on single-lane highways vehicles are modelled as particles which hop forward from one site to another on a one dimensional lattice and the inter-particle interactions mimic the manner in which the real vehicles influence each other's motion. In this model the number of empty lattice sites in front of a particle is taken to be a measure of the corresponding distance-headway(DH). The time-headway(TH) is defined as the time interval between the departures (or arrivals) of two successive particles recorded by a detector placed at a fixed position on the model highway. We investigate the effects of spatial inhomogeneities of the highway (static hindrances) on the DH and TH distributions in the steady-state of this model., 21 pages LATEX, 5 postscript figures; European Physical Journal B, vol.5, 781 (1998)

1. A supervised learning procedure was applied to individual cat area 17 neurons to test the possible role of neuronal co-activity in controlling the plasticity of the spatial 'on-off' organization of visual cortical receptive fields (RFs). 2. Differential pairing between visual input evoked in a fixed position of the RF and preset levels of postsynaptic firing (imposed iontophoretically) were used alternately to boost the 'on' (or 'off') response to a 'high' level of firing (S+ pairing), and to reduce the opponent response (respectively 'off' or 'on') in the same position to a 'low' level (S- pairing). This associative procedure was repeated 50-100 times at a low temporal frequency (0.1-0.15 s-1). 3. Long-lasting modifications of the ratio of 'on-off' responses, measured in the paired position or integrated across the whole RF, were found in 44 % of the conditioned neurons (17/39), and in most cases this favoured the S+ paired characteristic. The amplitude change was on average half of that imposed during pairing. Comparable proportions of modified cells were obtained in 'simple' (13/27) and 'complex' (4/12) RFs, both in adult cats (4/11) and in kittens within the critical period (13/28). 4. The spatial selectivity of the pairing effects was studied by pseudorandomly stimulating both paired and spatially distinct unpaired positions within the RF. Most modifications were observed in the paired position (for 88 % of successful pairings). 5. In some cells (n = 13), a fixed delay pairing procedure was applied, in which the temporal phase of the onset of the current pulse was shifted by a few hundred milliseconds from the presentation or offset of the visual stimulus. Consecutive effects were observed in 4/13 cells, which retained the temporal pattern of activity imposed during pairing for 5-40 min. They were expressed in the paired region only. 6. The demonstration of long-lasting adaptive changes in the ratio of 'on' and 'off' responses, expressed in localized subregions of the RF, leads us to suggest that simple and complex RF organizations might be two stable functional states derived from a common connectivity scheme.

A high degree of control over the structure and dynamics of domain patterns in nonequilibrium systems can be achieved by applying nonuniform external fields near parity breaking front bifurcations. An external field with a linear spatial profile stabilizes a propagating front at a fixed position or induces oscillations with frequency that scales like the square root of the field gradient. Nonmonotonic profiles produce a variety of patterns with controllable wavelengths, domain sizes, and frequencies and phases of oscillations., Published version, 4 pages, RevTeX. More at http://t7.lanl.gov/People/Aric/

An integral control strategy for activated sludge plants presented in this paper consists of three low-level control tasks. The first is the actual respiration rate control by manipulating the influent flow rate, whereby the aerators are at a fixed position for each setpoint. The second task is the maximum respiration rate control by manipulating the waste activated sludge flow rate. The third task of the integral control strategy is the instantaneous respiration rate monitoring, which informs the operator about the performance of the process.

It is proved that there exists a path P"l(x,y) of length l if d"A"Q"""n(x,y)@?l@?2^n-1 between any two distinct vertices x and y of AQ"n. Obviously, we expect that such a path P"l(x,y) can be further extended by including the vertices not in P"l(x,y) into a hamiltonian path from x to a fixed vertex z or a hamiltonian cycle. In this paper, we prove that there exists a hamiltonian path R(x,y,z;l) from x to z such that d"R"("x","y","z";"l")(x,y)=l for any three distinct vertices x, y, and z of AQ"n with n>=2 and for any d"A"Q"""n(x,y)@?l@?2^n-1-d"A"Q"""n(y,z). Furthermore, there exists a hamiltonian cycle S(x,y;l) such that d"S"("x","y";"l")(x,y)=l for any two distinct vertices x and y and for any d"A"Q"""n(x,y)@?l@?2^n^-^1.

Recent studies provide evidence that bacterial chromosomes are replicated by an enzyme factory, the replisome, located at a fixed position at the center of the cell; the fixed replisome could be a major factor in determining chromosome order in the cell, and may provide the force that drives chromosome segregation.