Size Of Circle Research Articles

The aging brain: Movement speed and spatial control

Background/Objectives: With aging, people commonly develop motor slowing (bradykinesia). Although this slowness with aging may be entirely related to degradation of the cerebral networks important in motor programing, it is possible that, at least in part, it may be a learned procedure for enhancing the accuracy and/or precision of movements. The goal of this study is to test these contradictory hypotheses. Methods: Twenty-four healthy adults, 12 younger than age 26 and 12 older than age 65 were asked to make alternative marks with a pen between a card centered in front of them and a series of circles distributed across a page. Performance was timed, and participants were instructed to complete the task as quickly as possible while not sacrificing accuracy for speed. The circle sizes and hand used varied by trial. Results: The older adults performed the task more slowly for all target circle diameters. As the circles decreased in size, the younger adults performed the task more rapidly than did the older participants, but the younger participants also had a greater decline in accuracy. Conclusions: During this aiming task, healthy older adults were less likely than younger adults to sacrifice accuracy for speed. Thus, at least in part, their slowing may be a learned adaptive strategy.

The power of populations: How the brain represents features and summary statistics

Introduction. Much recent interest has been directed at perception of summary statistics. As discussed in a variety of presentations at this and previous VSS meetings, intensive research has uncovered diverse dimensions of summary statistic perception, including simple and complex dimensions (from circle size and Gabor orientation to face emotion and attractiveness), the type of statistics acquired (mean, variance, range), and our ability to summarize elements presented simultaneously or sequentially and to divide displays into separate groups, detecting statistics of each. Methods. I now tackle a central question that remains unanswered: How does the brain compute scene summary statistics without first attaining knowledge of each scene element? One possible solution is that the brain uses implicit individual element information to compute summary statistics, which become consciously accessible first. I show that this added step is superfluous. On the contrary, direct acquisition of summary statistics is not surprising and no novel computational principle is required for summary perception. Results. A simple population code representation, as found for single element parameters, may be scaled up to compute mean values for element groups. The range of active neurons is broader, but the computation is the same for sets of elements as for a single element. Using a population code adds tremendous power, as it allows direct determination of which elements to include in the set, which elements are outliers – to be excluded and trigger pop out attention – and how to divide between simultaneously presented sets. Conclusion. Population coding provides a direct and efficient representation of set summary statistics. As suggested by Reverse Hierarchy Theory, conscious perception may begin with summary statistics, seeing many similar elements as a group, and only later focus attention to individual elements. Interestingly, a similar population code representation may underlie categorization, including both category prototype and its boundaries. Meeting abstract presented at VSS 2016

Ubiquitously expressed genes participate in cell-specific functions via alternative promoter usage.

How do different cell types acquire their specific identities and functions is a fundamental question of biology. Previously significant efforts have been devoted to search for cell-type-specifically expressed genes, especially transcription factors, yet how do ubiquitously expressed genes participate in the formation or maintenance of cell-type-specific features remains largely unknown. Here, we have identified 110 mouse embryonic stem cell (mESC) specifically expressed transcripts with cell-stage-specific alternative transcription start sites (SATS isoforms) from 104 ubiquitously expressed genes, majority of which have active epigenetic modification- or stem cell-related functions. These SATS isoforms are specifically expressed in mESCs, and tend to be transcriptionally regulated by key pluripotency factors through direct promoter binding. Knocking down the SATS isoforms of Nmnat2 or Usp7 leads to differentiation-related phenotype in mESCs. These results demonstrate that cell-type-specific transcription factors are capable to produce cell-type-specific transcripts with alternative transcription start sites from ubiquitously expressed genes, which confer ubiquitously expressed genes novel functions involved in the establishment or maintenance of cell-type-specific features.

Overlapping of Sturge-Weber Syndrome and Klippel-Trenaunay Weber Syndrome With Upper Limb Involvement

Introduction: The phakomatoses are a group of clinical disorders that are linked. Overlap between Sturge-Weber syndrome (SWS) and Klippel-Trenaunay Weber syndrome (KTWS) is very rarely. We presented a case of SWS with KTWS that involved upper limb. Case Presentation: A 24- year-old male with extensive port-wine staining over left side of his face, extending to lower eyelids, cheeks, neck and left upper extremity. The size of mid arm circle in left side was 34 cm and in right side was 27 cm. Conclusions: This is a case of overlap SWS and KTWS that involved upper limb.

Safe engineering of CAR T cells for adoptive cell therapy of cancer using long-term episomal genetransfer.

Chimeric antigen receptor (CAR) T‐cell therapy is a new successful treatment for refractory B‐cell leukemia. Successful therapeutic outcome depends on long‐term expression of CAR transgene in T cells, which is achieved by delivering transgene using integrating gamma retrovirus (RV) or lentivirus (LV). However, uncontrolled RV/LV integration in host cell genomes has the potential risk of causing insertional mutagenesis. Herein, we describe a novel episomal long‐term cell engineering method using non‐integrating lentiviral (NILV) vector containing a scaffold/matrix attachment region (S/MAR) element, for either expression of transgenes or silencing of target genes. The insertional events of this vector into the genome of host cells are below detection level. CD19 CAR T cells engineered with a NILV‐S/MAR vector have similar levels of CAR expression as T cells engineered with an integrating LV vector, even after numerous rounds of cell division. NILV‐S/MAR‐engineered CD19 CAR T cells exhibited similar cytotoxic capacity upon CD19+ target cell recognition as LV‐engineered T cells and are as effective in controlling tumor growth in vivo. We propose that NILV‐S/MAR vectors are superior to current options as they enable long‐term transgene expression without the risk of insertional mutagenesis and genotoxicity.

Phase diagram of a multiple forces model for animal group formation: marches versus circles determined by the relative strength of alignment and cohesion

Many species of fish, bird, and insect form groups of individuals that move together, called schools, flocks, or swarms, of characteristic shape and speed. Here we study a model that traces movements of many individuals, in which each individual moves at a constant speed, and changes its movement angle in response to its neighbors within a radius of interaction. Outside of a short range of separation (or repulsion), each individual changes moving direction to achieve a similar moving direction as its neighbors (alignment) and to move toward them (cohesion). Between each pair of individuals within an interaction range, both alignment and cohesion are at work simultaneously (multiple forces model). This is different from many other models for animal group formation in which only one of the two forces is at work (single force model), different forces operating in different zones of between-individual distance. Depending on the relative strength of alignment and cohesion, our model produces groups of two distinct patterns: marches and circles. We showed the phase diagram of group patterns depending on the relative strength of alignment and cohesion. As the strength of alignment relative to cohesion increases, the shapes of groups change gradually in the following order: (1) circles, (2) mixture of circles and marches, (3) short marches, (4) long marches, (5) wide marches. We derived a formula for the spatial size of circles, which explains that the radius of circles does not change with the number of individuals, but it increases with moving speed and decreases with the sensitivity of moving direction to neighbors.

A Model for Predicting Effect of Treatment on Progression-Free Survival Using Minimal Residual Disease As a Surrogate Endpoint in Chronic Lymphocytic Leukemia

A Model for Predicting Effect of Treatment on Progression-Free Survival Using Minimal Residual Disease As a Surrogate Endpoint in Chronic Lymphocytic Leukemia

Seeing the Big Picture: Size Perception Is More Context Sensitive in the Presence of Others.

This paper tests the hypothesis that social presence influences size perception by increasing context sensitivity. Consistent with Allport’s prediction, we expected to find greater context sensitivity in participants who perform a visual task in the presence of other people (i.e., in co-action) than in participants who perform the task in isolation. Supporting this hypothesis, participants performing an Ebbinghaus illusion-based task in co-action showed greater size illusions than those performing the task in isolation. Specifically, participants in a social context had greater difficulty perceiving the correct size of a target circle and ignoring its surroundings. Analyses of delta plot functions suggest a mechanism of interference monitoring, since that when individuals take longer to respond, they are better able to ignore the surrounding circles. However, this type of monitoring interference was not moderated by social presence. We discuss how this lack of moderation might be the reason why the impact of social presence on context sensitivity is able to be detected in tasks such as the Ebbinghaus illusion.

Consistent rationalization of type-2 topoisomerases' unknotting, decatenating, supercoil-relaxing actions and their scaling relation

How type-2 topoisomerases discern global topology from local properties of DNA is not known precisely but the hypothesis that the enzymes selectively pass double-helix strands at hook-like juxtapositions is promising. Building upon an investigation of unknotting and decatenating using an improved wormlike DNA model, here we focus primarily on the enzymes' action in narrowing the distribution of linking number (Lk) in supercoiled DNA. Consistent with experiments, with selective passage at a hooked juxtaposition, the simulated narrowing factor RLk diminishes with decreasing DNA circle size but approaches an asymptotic RLk ≈ 1.7–1.8 for circle size ≳3.5 kb. For the larger DNA circles, we found that (RLk − 1) ≈ 0.42log10RK ≈ 0.68log10RL and thus RK ≈ (RL)1.6 holds for the computed RLk and knot and catenane reduction factors RK and RL attained by selective passage at different juxtaposition geometries. Remarkably, this general scaling relation is essentially identical to that observed experimentally for several type-2 topoisomerases from a variety of organisms, indicating that the different disentangling powers of the topoisomerases likely arise from variations in the hooked geometries they select. Taken together, our results suggest strongly that type-2 topoisomerases recognize not only the curvature of the G-segment but also that of the T-segment.

Kernels and Ecological Niche Modeling

Photographs by Mathieu Denoël Kernel density estimators (KDEs) are a powerful tool to delineate conservation areas, but they have not been applied at the population level on patch-distributed organisms. This would be particularly worthy for species that need broad habitats beyond those where they can be sampled, such as terrestrial lands for pond-breeding amphibians. The aim of this study was to compare different approaches for the identification of suitable areas for conservation: KDE, ecological niche modelling, and a combination of KDE and niche models. Paedomorphosis in newts was chosen as a model system because this is an important form of intraspecific variation that is present in numerous taxa, but geographically localized within species and globally endangered. Overall, the best results were observed by the KDE integrating ecological barriers, and by the combination between KDE and niche modelling. This study highlights that KDEs are a pertinent tool in providing quantitative spatial measurements to delineate conservation areas based on patch-abundance data with a specific focus to connectivity. Paedomorphic palmate newt (Lissotriton helveticus) from Southern Larzac (St-Michel “Le Laquet,” France). In contrast to the dispersal metamorphosed phenotype, paedomorphs are fully aquatic organisms that retain larval traits such as gills at the adult stage. A typical pond of Southern Larzac (Le Coulet “Tournant,” France) where paedomorphic and metamorphic palmate newts (Lissotriton helveticus) can be found. The terrestrial environment is necessary for allowing population persistence and connectivity between sites by metamorphosed dispersers. A cartographic representation of Kernel Density Estimators (KDEs) for paedomorphic palmate newts (Lissotriton helveticus) in southern Larzac (France). The average number of paedomorphs caught per pond is proportional to the size of full circles. KDEs from 10 to 95% are shown. These photographs illustrate the article “Using kernels and ecological niche modeling to delineate conservation areas in an endangered patch-breeding phenotype” by Mathieu Denoël and Gentile Francesco Ficetola, tentatively scheduled to appear in Ecological Applications 25(7), October 2015. http://dx.doi.org/10.1890/14-1041.1

Extinction debt of a common shrub in a fragmented landscape

Fil: Gonzalez Varo, Juan P.. Consejo Superior de Investigaciones Cientificas. Estacion Biologica de Donana; Espana

The Dynamic Ebbinghaus: motion dynamics greatly enhance the classic contextual size illusion.

The Ebbinghaus illusion is a classic example of the influence of a contextual surround on the perceived size of an object. Here, we introduce a novel variant of this illusion called the Dynamic Ebbinghaus illusion in which the size and eccentricity of the surrounding inducers modulates dynamically over time. Under these conditions, the size of the central circle is perceived to change in opposition with the size of the inducers. Interestingly, this illusory effect is relatively weak when participants are fixating a stationary central target, less than half the magnitude of the classic static illusion. However, when the entire stimulus translates in space requiring a smooth pursuit eye movement to track the target, the illusory effect is greatly enhanced, almost twice the magnitude of the classic static illusion. A variety of manipulations including target motion, peripheral viewing, and smooth pursuit eye movements all lead to dramatic illusory effects, with the largest effect nearly four times the strength of the classic static illusion. We interpret these results in light of the fact that motion-related manipulations lead to uncertainty in the image size representation of the target, specifically due to added noise at the level of the retinal input. We propose that the neural circuits integrating visual cues for size perception, such as retinal image size, perceived distance, and various contextual factors, weight each cue according to the level of noise or uncertainty in their neural representation. Thus, more weight is given to the influence of contextual information in deriving perceived size in the presence of stimulus and eye motion. Biologically plausible models of size perception should be able to account for the reweighting of different visual cues under varying levels of certainty.

The occurrence of triterpenoids from Euphorbia gummifera inside the fairy circles of Garub in the southern Namibian pro-desert

The cause and maintenance of the fairy circle phenomenon of the Namibian pro-desert have not yet been satisfactorily explained. Several diverse hypotheses have been put forward, but none have universally been accepted. In the current study a possible link between the barren patches (fairy circles) of the Garub region (southern Namibian pro-desert) and Euphorbia gummifera was investigated, by determining if a characteristic compound(s) from this poisonous plant is present inside the fairy circles. With the use of GCMS trace analysis it was possible to identify euphol, a characteristic triterpenoid of the Euphorbia genus, in substantial quantities in 19 out of 20 soil samples from inside fairy circles in the Garub region. Only trace amounts of euphol could be found in 3 of 20 samples from outside the fairy circles. This implies that E. gummifera was present where there are now fairy circles. A comparison of the size of the fairy circles and E. gummifera found within the same area (Garub) additionally linked the barren patches to E. gummifera. The circles in this area have an average diameter of 3.53m and the plants 3.44m. This study partially supports the first published hypothesis by Theron in 1979, that the fairy circles are caused by Euphorbia spp. or their remains.

The Ebbinghaus illusion: new contextual effects and theoretical considerations.

Current accounts of the Ebbinghaus illusion emphasize either size contrast or contour interaction processes. To assess these alternatives, four variants of the Ebbinghaus figure were constructed using 1, 5, 9, or 13 small circles dispersed along the perimeter of larger contextual circles. 30 observers ranked the perceived size of the central circles and a single control circle. The rankings indicated that increasing the number of small circles reduced the perceived size of the central circle. The results parallel the effects of contextual arcs on the Ebbinghaus illusion and suggest that the mis-estimations of central circle size in Ebbinghaus figures result primarily from contour interactions.

Friction circle estimation-based torque distribution control of six-wheeled independent driving vehicles for terrain-driving performance

This paper describes torque distribution control of six-wheeled in-wheel motor vehicles by considering the friction circle of each wheel for enhanced terrain-driving performance. Using control allocation, the proposed torque distribution algorithm determines the torque command to each wheel, by considering the size of the friction circle. The friction circle of each wheel is estimated using a linear parameterized tyre model with two threshold values. The parameters and the threshold values are computed from measurements of the wheel speed, the yaw rate, the acceleration and the torque command signals using a recursive least-squares method. Simulation studies were conducted using TruckSim and MATLAB/Simulink co-simulations. It was confirmed that the proposed friction circle estimation algorithm can be successfully used for torque distribution to enhance the terrain-driving and hill-climbing performance.

Effects of upper limb robot-assisted therapy in the rehabilitation of stroke patients

[Purpose] The aim of this study was to examine the effects of upper limb robot-assisted therapy in the rehabilitation of stroke patients. [Subjects and Methods] Fifteen stroke patients with no visual or cognitive problems were enrolled. All subjects received robot-assisted therapy and comprehensive rehabilitation therapy for 30 minutes each. The experimental group received a conventional therapy and an additional half hour per weekday of robot therapy. The patients participated in a total of 20 sessions, each lasting 60 minutes (conventional therapy 30 min, robot-assisted therapy 30 min), which were held 5 days a week for 4 weeks. [Result] The patients showed a significant difference in smoothness and reach error of the point to point test, circle size and independence of the circle in the circle test, and hold deviation of the playback static test between before and after the intervention. On the other hand, no significant difference was observed in the displacement of the round dynamic test. The patients also showed significant improvement in the Fugl-Meyer Assessment and Modified Barthel Index after the intervention. [Conclusion] These kinematic factors can provide good information when analyzing the upper limb function of stroke patients in robot-assisted therapy. Nevertheless, further research on technology-based kinematic information will be necessary.

Isolation and Preliminary Identification of Cellulose-Decomposing Microorganisms Form Bamboo Forest

For the conversion of cellulose into biofuel by microorganisms is being studied intensively. This research isolate and screen efficient cellulolytic microorganism from bamboo forest soil based on growth rate on CMC plate, the size of transparent circle, disintegration effect of filter paper, and CMC enzyme activity assay. As a result, efficient cellulose-decomposing fungus J6-1 was obtained. The strains possessed higher filter paper degrading ability and CMC enzyme activity, disintegrating the filter paper into 42.3% at the 5th days and reaching the highest CMC enzyme activity 6.87IU/mL after 120 hours of shake flask fermentation. Strains J6-1 is preliminarily identified asPenicilliumby morphological observation and a great potential cellulolytic strains.

Fuzzy Algorithm of discontinuity sets

The clustering of discontinuity sets is not always a trivial task, especially when only the pole density diagram is used, the classical method. This process is extremely subjective since the size of the counting circle, the pole overlapping, and the presence of outliers between families make it difficult to define their characteristics. In these cases, it is useful to apply numerical and classical methods together. For that, this article proposes an algorithm based on the Fuzzy K-means method that allows the clustering of the discontinuities without the influence of these factors. The algorithm had its results compared to two fracture sets studied in literature and it has proved its efficiency.

Endpoint distinctiveness facilitates analogical mapping in pigeons

Analogical thinking necessitates mapping shared relations across two separate domains. We investigated whether pigeons could learn faster with ordinal mapping of relations across two physical dimensions (circle size & choice spatial position) relative to random mapping of these relations. Pigeons were trained to relate six circular samples of different sizes to horizontally positioned choice locations in a six alternative matching-to-sample task. Three pigeons were trained in a mapped condition in which circle size mapped directly onto choice spatial position. Three other pigeons were trained in a random condition in which the relations between size and choice position were arbitrarily assigned. The mapped group showed an advantage over the random group in acquiring this task. In a subsequent second phase, relations between the dimensions were ordinally reversed for the mapped group and re-randomized for the random group. There was no difference in how quickly matching accuracy re-emerged in the two groups, although the mapped group eventually performed more accurately. Analyses suggested this mapped advantage was likely due to endpoint distinctiveness and the benefits of proximity errors during choice responding rather than a conceptual or relational advantage attributable to the common or ordinal mapping of the two dimensions. This potential difficulty in mapping relations across dimensions may limit the pigeons’ capacity for more advanced types of analogical reasoning.This article is part of a Special Issue entitled: Tribute to Tom Zentall.

Strong interaction between plants induces circular barren patches: fairy circles.

Fairy circles consist of isolated or randomly distributed circular areas devoid of any vegetation. They are observed in vast territories in southern Angola, Namibia and South Africa. We report on the formation of fairy circles, and we interpret them as localized structures with a varying plateau size as a function of the aridity. Their stabilization mechanism is attributed to a combined influence of the bistability between the bare state and the uniformly vegetation state, and Lorentzian-like non-local coupling that models the competition between plants. We show how a circular shape is formed, and how the aridity level influences the size of fairy circles. Finally, we show that the proposed mechanism is model-independent.