Top PDF Perception of space by multiple intrinsic frames of reference.

Perception of space by multiple intrinsic frames of reference.

Perception of space by multiple intrinsic frames of reference.

The discrepancies between the physical space and the psychological space manifest themselves in the judgment of geographical information such as locations and bearings [2,6– 13]. Stevens and Coupe [12] first proposed that the representa- tions of spatial relations are hierarchically organized. Hirtle and Jonides [6] suggested that people misjudge geographical locations with the biases or distortions appearing to be based on subjective spatial categories. When asked to point out landmarks in a map, participants in Hirtle and Jonides’ experiments overestimated distances for between-cluster pairs and underestimated them for within-cluster pairs, suggesting that they formed subjective spatial categories even without seeing well-defined boundaries in the space. The category adjustment model [14–15] suggests that people represent spatial locations at more than one level of spatial resolution. Huttenlocher, Hedges, and Duncan [14] showed participants a circle with a dot in it then asked the participants to reproduce the dot position based on memory. They found that the reproduced positions systematically deviated from their original positions. Specifically, if the circle was divided into horizontal-vertical and radial slices, the reproduced dots were often displaced toward the center of the slices in which they fall. This result suggests that a psychological space might be hierarchically represented and there is a central tendency at each hierarchical level (e.g., the slice) which all other spatial information
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Postural adaptation of the spatial reference frames to microgravity: back to the egocentric reference frame.

Postural adaptation of the spatial reference frames to microgravity: back to the egocentric reference frame.

Despite the absence of visual cues and of graviceptive information, some subjects were able to maintain a horizontal forearm’s position. This indicates that they were able to build an external reference frame by integrating angular displacement of all joints involved in STS movement, and/or dynamics propriocep- tive cues stemming from the inertia moment, of our limbs with the haptic (cutaneous plantar cues) and vestibular (coming from head acceleration) information in order to estimate the absolute angle of the forearm (body scheme) and maintain it in horizontal position. This suggests also that this ability to independently control the forearm and trunk under microgravity condition might be based on the use of the postural body scheme [10]. Other authors have used the body scheme concept to explain subjects’ ability to stabilise their head in space despite the perturbations resulting from the voluntary trunk oscillations occurring under short-term and long-term microgravity conditions [41,42]. Mergner and Rosemeier [43] have suggested that under microgravity condi- tions, simply making contact with the space cabin may suffice to update the interactions between the various sensory inputs involved in postural control. On the other hand, Lackner and DiZio [44] have established that in the absence of graviceptor activation, foot plant cues activate an internal model mediating perception of the Z-axis. Indeed, it has been proposed that an internal representation of body vertical has a prominent role in spatial orientation. A recent study during free-floating with no contact cues, reports that the normal longitudinal body axis perception is altered and that the normal accuracy is reinstated by the application of tactile cues on the subject’s chest [6]. Nevertheless, in the present study, the subjects were able to use cutaneous plantar cues and the proprioceptive information of all joints of the kinematic chain involved in the movement execution not only to perceive the Z axis, but also to control the geometrical relationships between their various body segments.
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The frames of reference of the motor-visual aftereffect.

The frames of reference of the motor-visual aftereffect.

Repeatedly performing similar motor acts produces short-term adaptive changes in the agent’s motor system. One striking use-dependent effect is the motor-to-visual aftereffect (MVA), a short-lasting negative bias in the conceptual categorization of visually-presented training-related motor behavior. The MVA is considered the behavioral counterpart of the adaptation of visuomotor neurons that code for congruent executed and observed motor acts. Here we characterize which features of the motor training generate the MVA, along 3 main dimensions: a) the relative role of motor acts vs. the semantics of the task-set; b) the role of muscular-specific vs. goal-specific training and c) the spatial frame of reference with respect to the whole body. Participants were asked to repeatedly push or pull some small objects in a bowl as we varied different components of adapting actions across three experiments. The results show that a) the semantic value of the instructions given to the participant have no role in generating the MVA, which depends only on the motor meaning of the training act; b) both intrinsic body movements and extrinsic action goals contribute simultaneously to the genesis of the MVA and c) changes in the relative position of the acting hand compared to the observed hand, when they do not involve changes to the movement performed or to the action meaning, do not have an effect on the MVA. In these series of experiments we confirm that recent motor experiences produce measurable changes in how humans see each others’ actions. The MVA is an exquisite motor effect generated by two distinct motor sub-systems, one operating in an intrinsic, muscular specific, frame of reference and the other operating in an extrinsic motor space.
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Determination Of Longevity Of Teeth In Buckets Of Loading Equipment In Coal Mines - A Case Study

Determination Of Longevity Of Teeth In Buckets Of Loading Equipment In Coal Mines - A Case Study

The abrasivity of rock which is a main contributory geological condition can be described by the petrographic composition, in particular the contribution of hard minerals like quartz. Determination of quartz or equivalent quartz content can be done by microscopic examination of a thin section. Alternatively by laboratory tests where some kind of model or index test is used. In the present paper the Cerchar abrasivity test as well as the Laboratoire des Ponts et Chaussées (LCPC) abrasivity test is employed and its comparison with other methods has also been made. Abrasion is the wearing or tearing away of particles from the surface. More abrasive the rocks are, the higher the operation costs. The mechanization of the excavation methods associated with increased advancement rate or increased production rates in mining require a greater knowledge of rock abrasivity. Abrasiveness of rock cannot be predicted with a high degree of accuracy. In recent years, the studies on determining the abrasiveness of rocks have been carried out intensively. There are several methods for estimating the abrasiveness of rocks and minerals, used with various degree of success and relevance. They can be broadly divided into three categories:
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The peri-saccadic perception of objects and space.

The peri-saccadic perception of objects and space.

cesses is a particular strength of our approach. The cells shown in Figure 4A and 4B exemplify the fact that the receptive field effects in our model are dependent on the relative locations of fixation, saccade target, and center of the receptive field. The similarity of our model observations with studies in different brain areas raises the fundamental question about the nature of peri-saccadic receptive field changes. We demonstrated that our model predicts the remapping of receptive fields for receptive field positions that have been commonly used to investigate remapping [4,6,7,41]. For other locations, however, the model is consistent with observations made in V4 where receptive fields tend to shift towards the saccade target and not along the saccade vector [3]. Do V4 receptive field dynamics differ from other areas? For example, does remapping occur primarily in oculomotor-related areas whereas our model describes properties of areas involved in the computation of object identity? Or is remapping not homogeneous across visual space, but a special case that applies only within a certain part of the visual field? A non-homogeneous remap- ping could reconcile the different observation made in V4. No study has yet systematically addressed this question. Such systematic investigations of 2D receptive field dynamics in different brain areas are required, specifically in those which receive oculomotor feedback, e.g., area V4, MT, MST, V3a, TEO, LIP and VIP.
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Use of space by neotr

Use of space by neotr

In the present study the food availability was not mea- sured. However, considering the small size of the fragment and the high anthropic pressure surrounding it, we believe that food supplies are limited. Thus, the skewed sex ratio observed of 1.45 females for each marked male can be reflecting this so- phisticated reproductive strategy. Assuming limited food avail- ability in anthropized environments it could be that parental care is restricted as a consequence of this limited food avail- ability, resulting in the observed higher numbers of females. Experiments directed to prove this hypothesis should be made before specific conclusions about this phenomena in the study area can be determinated. On the other hand, the sexual ratio deviation for females could result of a characteristic of the cap- ture method. In the reproduction season, adult males disperses more than females to get sexual partnership and then can be their capturability decreased (C ÁCERES 2003).
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The Influence of Small Amounts of Aluminium on the Spheroidization of Cast Iron with Cerium Mischmetal

The Influence of Small Amounts of Aluminium on the Spheroidization of Cast Iron with Cerium Mischmetal

The work was aimed to determine the influence of aluminium in the amount from about 0.6% to about 2.8% on the structure of cast iron treated with cerium mischmetal and subjected to graphitizing modification with 75% ferrosilicon. Four experimental melts were held during the investigation. The charge was composed of the specially prepared grey iron, containing the basic elements within the presumed limits. While determining the desirable quantity of carbon in the charge cast iron, two contradicting conditions were taken into account, i.e. that the purpose is to achieve the nodular cast iron (which means that the relatively large carbon amount would be demanded) and that introducing aluminium to the melt results in the decreased solubility of carbon in cast steel. Taking this into account, it was stated that the quantity of carbon in the charge cast iron should be maintained within the range of 3.2÷3.4%. It has been assumed that the silicon content in the charge material should fall within 0.7÷1.0%, as it was during the former investigations. Manganese content was restricted to 0.1% maximally in order to achieve the desired structure with ferrite fraction as high as possible. It has been also assumed that the content of both sulphur and phosphor should be at the possible lowest level.
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Effect of water glass modification with nanoparticles of zinc oxide on selected physical and chemical properties of binder and mechanical properties of sand mixture

Effect of water glass modification with nanoparticles of zinc oxide on selected physical and chemical properties of binder and mechanical properties of sand mixture

Nanoparticles as a new generation of materials are used in many fields. The basic methods for their preparation are the top- down and bottom-up techniques. The essence of the top-down technique consists in grinding the material to particles with nano dimensions, while the bottom-up technique assumes making structures from molecules or single atoms [1,2]. According to a method recently developed, the nanoparticles of metal oxides are produced through anodic dissolution of metals [3]. There are also thermal methods of obtaining metal nanoxides [4-7].
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Buying Behavior Of Organic Vegetables Product The Effects Of Perceptions Of Quality And Risk

Buying Behavior Of Organic Vegetables Product The Effects Of Perceptions Of Quality And Risk

the countries in Asia as Malaysia had more intentions of organic products from the customers in view of the importance of health on environmental issues (Saleki et al., 2012:99). This shows that attentions to organic products are already quite well received by the community. However, there needs to be studied perception of organic products in Indonesia, because Indonesia is a developing country which has a population density is quite high compared from Malaysia. And consumption of vegetable, especially organic vegetable products is still low in Indonesia (Amin, 2014:13), in particularly the province of West Java. An organic vegetable product offered by retail supermarket is assessed by consumers in both of sides, quality and risk. Price is a risk that should be accepted by consumers when buying organic vegetables. Hence, price of organic vegetables is more expensive than conventional vegetable products (Radman, 2005:263). Value of the risk products is very important for customer, which has an impact on consumer purchasing decisions (Yee et al., 2011:55). Nowadays consumers buy organic products is not as aware of the health and environmental effects but because of advised and habit of surroundings (Guido et al., 2010:99). In addition, not all consumers considered that by buying organic products, have been keeping or help conserve the environment (Arvola, 2008:449). It is alleged lack of consumer understanding of product quality organic vegetables. On last study it was discovered that the perceived quality is strong relationship with consumer purchasing decisions (Yee et al., 2011:55). Consumer’s had perception of organic products is because of quality and safety, in addition to some other benefits (Zanoli et al., 2012:70). Customer value of product influenced purchase decision of products (Shareef, 2008:105). Organic vegetable products have value in consumer where quality and satisfactions become value for consumers (Ying & Chiu, 2012:125). Higher value of consumer product quality of organic vegetables is more possibility to purchase decisions of organic vegetable products who offered in retail supermarkets. Based on previously phenomenon, this study examines the level of consumer perceptions of quality and risk in organic vegetables, as well as the impact on consumer purchasing decisions.
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Evaluation of susceptibility of the ZRE1 alloy to hot cracking in conditions of forced strain

Evaluation of susceptibility of the ZRE1 alloy to hot cracking in conditions of forced strain

The nil strength temperature (NST) for the alloy was determined by testing cylindrical Ø 6 x 90 mm specimens on the Gleeble 3800 simulator. S-type thermocouples were pressure welded to the specimens, and then the specimens were fixed in the chamber by means of copper holders. Constant distance of 52.4 mm was kept between the holders. After evacuation of air, the chamber was filled with argon (to 0.14 hPa). Then, the 0.6 – 0.7 kN minimum pre-load was applied and was maintained until the end of experiment. The specimens were heated at the 20 o C/s rate to 400 o C, and then at the 1 o C/s rate. The NST was determined as the temperature at which the specimen lost its cohesion. The NST for the ZRE1 alloy in as-delivered state is 535 o C.
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Statistical Assessment of the Effect of Chemical Composition on Mechanical Properties of Hypereutectic AlSi17CuNiMg Silumin

Statistical Assessment of the Effect of Chemical Composition on Mechanical Properties of Hypereutectic AlSi17CuNiMg Silumin

Good physical and technological properties are the reason why silumins have found wide application in various branches of the engineering industry, among others, in aviation, building industry, electronic and electro-engineering industry and, last but not least, in automotive industry. And yet, though offering numerous advantages, silumins are also characterised by a very important drawback. From the technical viewpoint this is their tendency to the formation of a coarse-grained structure, adversely affecting the mechanical properties of castings. For this reason, silumins after the refining treatment should be subjected to modification.
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Influence of supply voltage frequency of induction coil on inoculation efficiency of pure aluminium structure

Influence of supply voltage frequency of induction coil on inoculation efficiency of pure aluminium structure

On the basis of conducted analysis of studies results was affirmed, that rotate electromagnetic field generated by induction coil fed with frequency of supply voltage larger than power network, influences on liquid metal in time of its solidification in mould, guarantees refinement of structure of pure Al without necessity of application of inoculants sort Ti and B. This method of inoculation is important, because Ti and B decrease the degree of purity and electrical conductivity of pure aluminium. Moreover Ti and B are reason of point cracks formation during rolling of ingots. This method of inoculation was been possible to apply in conditions of continuous casting because allows on producing of ingots from aluminium about purity 99,5% with structure without columnar crystals, which are unfavourable from point of view of usable properties.
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The modification process of AlSi21CuNi silumin and its effect on change of mechanical properties of the alloy

The modification process of AlSi21CuNi silumin and its effect on change of mechanical properties of the alloy

Due to difficulties present during machining operations and with segregation of crystals of primary silicon, hypereutectic silumins can be used after modification only. It is why elaboration of effective modification methods is necessary for complete utilization of such alloys for machinery parts made from castings. In the paper are presented test results concerning an effect of modification with phosphor copper and strontium of AlSi21CuNi silumin on change of its mechanical properties (R B m B , A B 5 B ) and its structure. Investigated alloy was melted in
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Effect of Multipoint Sequential Water Mist Cooling of Casting Die on Microstructure and Mechanical Properties of AlSi11 Alloy

Effect of Multipoint Sequential Water Mist Cooling of Casting Die on Microstructure and Mechanical Properties of AlSi11 Alloy

Research metal chill (Fig. 2) was made of X38CrMoV5-1 steel. In the body of the chill were installed symmetrically 3 sections of cooling nozzles. The nozzles were placed in such a way that each section of the nozzles cooled each zone of the chill and the casting. Cooling jets was controlled by the computer control system (Fig. 1, pos. 6) developed by Z-Tech Company. The system software includes a set of functions and procedures to monitor and control the course of the water mist generation in the multi-circuit cooling system using a pre-drafted program. In this metal casting die (Fig. 2) the "Rm" samples were cast from technical unmodified silumin AlSi11, using cooling methods M1- M5 presented in Table 1.
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Evaluation of the readiness of the ait organization artificial satellites applied for stakeholders requirements/  Avaliação da prontidão dos satélites artificiais da organização da ait aplicados aos requisitos das partes interessadas

Evaluation of the readiness of the ait organization artificial satellites applied for stakeholders requirements/ Avaliação da prontidão dos satélites artificiais da organização da ait aplicados aos requisitos das partes interessadas

translated into research and future development. TRL 2 have been studied the basic principles and the practical applications can be implemented to the initial discoveries. TRL 3 performs analytical and laboratorial studies to confirm if a technology is feasible and / or is ready to proceed through the development process, this is the level where a proof-of-concept model is usually built. TRL 4, tests several components to demonstrate interoperability between each other. The TRL 5 is a continuation of the TRL4, however, a technology identified in 5 as a breadboard technology must perform more rigorous tests. In TRL 6 a fully functional prototype or representational model of the technology is developed, going to TRL 7 the technology cited will require a working model or prototype being demonstrated in a spatial environment. TRL 8 presents the technology tested and "qualified for flight" being ready to be implemented. Finally if the technology is proven in-flight during a successful mission is called TRL 9.
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Epileptogenic focus localization and complexity analysis of its BOLD signal

Epileptogenic focus localization and complexity analysis of its BOLD signal

54 After performing the RTCs number reduction and its normalization, 16 RTCs remained for statistical analysis. From those 16 RTCs only 4 (RTC_1, RTC_5, RTC_7, and RTC_15) resulted in a SPM (using a FWER correction with p-value<0.05 and k-threshold of 27 voxels). Fig. 32 shows each map with the corresponding RTC. Each label on the left of the matrix has the form of ‘Idx: RTC#_size’ or ‘Idx: RTC#_size_c’, where Idx represents the index of the label, # the number of the RTC that produced the SPM, size stands for the size of the cluster being analyzed, and c means contralateral cluster. This labeling stands for all patients. The temporal profile of the remaining RTCs are presented in Appendix C. The maps from RTC 1 and RTC 15 show extensive and diffuse activation on anterior and posterior brain areas, respectively, thus, these maps were excluded from further analysis. RTC_5’s map shows four well defined activated regions, comprising the following brain regions: left temporal cortex, left superior occipital cortex, left lingual gyrus and right parahippocampal gyrus. Finally, the map corresponding to RTC_7 show one activation spot on the calcarine fissure. The content, regarding the number and size of clusters, of each SPM are presented in Table 2 . Each cluster are reported individually in Appendix C.
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Modification of water glass with colloidal slurries of metal oxides

Modification of water glass with colloidal slurries of metal oxides

Water glass is an alternative binder for moulding and core sands with organic binders. It is inexp ensive, easily available and non-toxic. Besides the advantages of the sands combined with this binder, there are also some negative characteristics, such as: brittleness, a worse knock-out property and a more difficult recovery. On the other hand, it is known that the abilities of water glass as a binder of moulding and core sands are not fully utilized. This leads to the necessity of a deeper understanding of its physico-chemical properties, such as: wettability, viscosity, as well as cohesive and adhesive strength, which enable a modification of the binder in the aspect of the improvement of the utilitarian parameters of the sand. The analysis of the technological properties of the sands with water glass shows that it is advisable to improve the strength p roperties of the sands by improving the cohesive and adhesive characteristics of the binder.
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The analysis of solidification process of ferritic-austenitic cast steel

The analysis of solidification process of ferritic-austenitic cast steel

One of the most common defects leading to the rejection of faulty castings made of duplex cast steel is hot cracking. Hot cracking – differently from cold cracking which occur on cooling, when the material exhibits already distinct elastic properties – proceeds in the semi-solid state, particularly when the temperature of solidifying casting is close to the equilibrium solidus point. There exist a range of temperatures in the vicinity of the solidus point within which the solidifying metal shows very small deformation ability and small strength. Therefore even little stresses occurring at the solidification stage and caused by density difference between ferrite and austenite, or restricted shrinkage, or various temperature gradients, can be the reason of hot cracking. Copper addition, as it is used in cast steel grades implemented in Polish power industry applications, decreases the temperature of the end of solidification, thus affecting beneficially the surface reproduction quality, but on the other hand it can promote, along with several other elements contained in duplex cast steel, the peritectic transformation during the last stage of solidification. The presence of peritectic solidification, i.e. strictly speaking the structural stresses accompanying that process, is the well-known and significant reason of the increased steel defectiveness in the continuous steel casting (CSC) technology if the steel with carbon content promoting the peritectic transformation is processed.
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Effect of heat treatment parameters on the properties of low-alloy cast steel with microadditions of vanadium

Effect of heat treatment parameters on the properties of low-alloy cast steel with microadditions of vanadium

This article examines the effect of prolonged time of holding at the temperature of 620 0 C on the processes of secondary phase precipitation and mechanical properties of low-alloy cast steel with an addition of vanadium subjected to two variants of heat treatment, i.e. U:1150 0 C+H:950 0 C+O:620 0 C and H:950 0 C+O:620 0 C. To determine an impact of the applied heat treatment operations, testing of mechanical properties and microstructural examinations of the cast steel with 0,21 and 0,27%C were carried out.
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Bol. Ciênc. Geod.  vol.23 número3

Bol. Ciênc. Geod. vol.23 número3

Concerning the stations of the first case, we have six (6) old SLR mobile-stations and two (2) DORIS stations, referred to ITRF2008. For the cases (2), (3) and (4) the stations referred to continuously operating GNSS network and they are expressed to ETRF2000. The less accurate stations were the six old SLR mobile-stations. Nevertheless, we finally included all the stations since their standard deviations do not exceed the level of 5 cm, which was considered sufficient for the present study. We call them ‘external sites’ since they were not involved in the realization of HTRS07. The associated velocities were estimated from time series analysis (for more details for the time series analysis one can see e.g. Nikolaidis 2002)
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