Double Staircase Research Articles

Do we perceive sensations inside and outside of our body differently? Perceptual, emotional, and behavioral differences between visceral and somatic sensation, discomfort, and pain.

Experimental research evaluating differences between the visceral and somatic stimulation is limited to pain and typically uses different induction methods for visceral and somatic stimulation (e.g., rectal balloon distention vs. tactile hand stimulation). Our study aimed to compare differences in response time, intensity, unpleasantness, and threat between identical electrical visceral and somatic stimulations at both painful and non-painful perceptual thresholds. Electrical stimulation was applied to the wrist and distal esophagus in 20 healthy participants. A double pseudorandom staircase determined perceptual thresholds of Sensation, Discomfort, and Pain for the somatic and visceral stimulations, separately. Stimulus reaction time (ms, via button press), and intensity, unpleasantness, and threat ratings were recorded after each stimulus. General linear mixed models compared differences in the four outcomes by stimulation type, threshold, and the stimulation type-by-threshold interaction. Sigmoidal maximum effect models evaluated differences in outcomes across all delivered stimulation intensities. Overall, visceral stimulations were perceived as more intense, threatening, and unpleasant compared to somatic stimulations, but participants responded faster to somatic stimulations. There was no significant interaction effect, but planned contrasts demonstrated differences at individual thresholds. Across all delivered intensities, higher intensity stimulations were needed to reach the half-maximum effect of self-reported intensity, unpleasantness, and threat ratings in the visceral domain. Differences exist between modalities for both non-painful and painful sensations. These findings may have implications for translating paradigms and behavioral treatments from the somatic domain to the visceral domain, though future research in larger clinical samples is needed.

Bijection Between Increasing Binary Trees and Rook Placements on Double Staircases

In this paper, we shall construct a bijection between rook placements on double staircases (introduced by Josuat-Vergès in 2017) and increasing binary trees. We introduce two subclasses of rook placements on double staircases, which we call left and right-aligned rook placements. We show that their enumeration, while keeping track of a certain statistic, gives the $\gamma$-vectors of the Eulerian polynomials. We conclude with a discussion on a different bijection that fits in very well with our main bijection, and another discussion on generalising our main bijection. Our main bijection is a special case of a bijection due to Tewari (2019).

Staircase formation in unstably stratified double diffusive finger convection

Double diffusive staircases are experimentally investigated in a fluid layer with a stabilizing temperature gradient and a destabilizing gradient of ion concentration. Gradients of temperature and ion concentration are maintained in a steady state within an electrochemical system. Staircases are observed even if the density stratification is unstable. None of the previously proposed mechanisms for staircase formation can be recognized in the experiments. Ion transport through fingers that are part of a staircase is not the same as the transport through fingers extending through the entire cell. Fingers cease to exist if the diffusive heat transport between neighboring fingers is insufficient.

Architectural design and emergencies in double staircase high-rise buildings: the effect of geometric shape parameters on travel time

Emergency evacuation is a significant matter in high-rise buildings, as large numbers of occupants are in limited space. Evacuation standards and codes used by designers are closely related to interior spaces. However, the relationship between the general geometric shape of buildings and the evacuation process are major gaps in the literature. In this paper, we assessed the effect of three geometric parameters related to the general geometric shape of the building, namely the gyration radius, the average length and width of the bounding rectangle, and the ratio of the perimeter to the area of the shape on the travel time by using the agent-based method. The results show that gyration radius has the most direct relationship with the time of total travel and horizontal travel time and can be used as a suitable tool in the initial design stage used by architects and designers of buildings.

Bulacan capitol building: A reconnaissance survey of art deco heritage structure designed by Arch. Juan M. Arellano

The Capitol building of the Province of Bulacan in the town of Malolos, erected in 1930. Bulacan Capitol Building is an Art Deco Style Architecture. The entrance of the building has Portico with Octagonal Concrete Columns with decorative concrete torch. It has three entrances of wooden frame door accentuated with wrought iron grills with design of rising Sun. Upon entering the lobby, you will be welcomed by Grand double return staircase. The façade of the building is of massive walls and columns with simplistic design painted with purely white color. The Bulacan Capitol Building was designed by Architect Juan Marcos Arellano. JUAN MARCOS ARELLANO (y de Guzman), one of the Philippines' founding fathers of architecture, was born on this day in Tondo, Manila. Among his most famous works are Manila's Metropolitan Theater (1935), Legislative Building (1926) (now the National Museum of the Philippines), the Manila Central Post Office Building (1926), and Jones Bridge. The researcher utilized Reconnaissance Survey Methodology, an extensive study of an entire area that might be used for analysis. Its purpose is to eliminate those buildings or site elements which are impractical or unfeasible and to identify the more promising buildings or site elements. The result showed that one of the famous landmarks in Bulacan is its Provincial Capitol Building. The building, erected in 1930, was destroyed during the Second World War. It was rebuilt in 1950 with the assistance of the American government. During the administration of President Corazon C. Aquino, the building was renovated and expanded. The building is a Cultural Heritage Property.

Intermediate symplectic characters and shifted plane partitions of shifted double staircase shape

We use intermediate symplectic characters to give a proof and variations of Hopkins' conjecture, now proved by Hopkins and Lai, on the number of shifted plane partitions of shifted double staircase shape with bounded entries. In fact, we prove some character identities involving intermediate symplectic characters, and find generating functions for such shifted plane partitions. The key ingredients of the proof are a bialternant formula for intermediate symplectic characters, which interpolates between those for Schur functions and symplectic characters, and the Ishikawa--Wakayama minor-summation formula.Keywords: Intermediate symplectic characters, shifted plane partitions, minor-summation formula, Pfaffian .Mathematics Subject Classifications: 05A15, 05E05, 05E10

On the Topology of the Double Staircase

On the Topology of the Double Staircase

Plane partitions of shifted double staircase shape

We give a product formula for the number of shifted plane partitions of shifted double staircase shape with bounded entries. This is the first new example of a family of shapes with a plane partition product formula in many years. The proof is based on the theory of lozenge tilings; specifically, we apply the “free boundary” Kuo condensation due to Ciucu.

Frustrated Microparticle Morphologies of a Semicrystalline Triblock Terpolymer in 3D Soft Confinement.

Self-assembly of block copolymers (BCPs) in three-dimensional (3D) confinement of emulsion droplets has emerged as a versatile route for the formation of functional micro- and nanoparticles. While the self-assembly of amorphous coil-coil BCPs is fairly well documented, less is known about the behavior of crystalline-coil BCPs. Here, we demonstrate that confining a linear ABC triblock terpolymer with a crystallizable middle block in oil-in-water (O/W) emulsions results in a range of microparticles with frustrated inner structure originating from the conflict between crystallization and curved interfaces. Polystyrene-block-polyethylene-block-poly(methyl methacrylate) (PS-b-PE-b-PMMA, S32E36M3293) in toluene droplets was subjected to different preparation protocols. If evaporation was performed well above the bulk crystallization temperature of the PE block (Tevap > Tc), S32E36M3293 first microphase-separated into microparticles with lamella morphology followed by crystallization into a variety of frustrated morphologies (e.g., bud-like, double staircase, spherocone). By evaporating at significantly lower temperatures that allow the PE block to crystallize from solution (Tevap < Tc), S32E36M3293 underwent crystallization-driven self-assembly into patchy crystalline-core micelles, followed by confinement assembly into lenticular microparticles with compartmentalized hexagonal cylinder lattices. The frequency of these frustrated morphologies depends on polymer concentration and the evaporation protocol. These results provide a preliminary understanding of the morphological behavior of semicrystalline block copolymers in 3D soft confinement and may provide alternative routes to structure multicompartment microparticles from a broader range of polymer properties.

The case of Capogrossi in Rome: criteria and limits in the retouching process of a contemporary mural painting

This paper focuses on the reintegration treatments studied for a contemporary mural painting, which was designed and carried out by the Italian artist Giuseppe Capogrossi in 1954. This forgotten masterpiece is located on the ceilings of the main double staircase at the entrance of the Airone, an ex-cinema theatre in Rome, which was designed and planned during the Fifties by the famous architects Adalberto Libera, Eugenio Montuori and by the engineer Leo Calini. After a brief introduction based on the conservation history of the building and on the painting itself, it will be described criteria and limits in the reintegration process of a sample area of this highly degraded polyvinyl acetate (PVAc) based mural. The materials selected in the reintegration project, based on natural polymers and synthetic polymers, will be theoretically compared with one another and it will be explained why some of these could be appropriate and effective, while others could not chromatically work in this particular case.

Factors Influencing the Detection of Spatially-Varying Surface Gloss.

In this study, we investigate the ability of human observers to detect spatial inhomogeneities in the glossiness of a surface and how the performance in this task depends on several context factors. We used computer-generated stimuli showing a single object in three-dimensional space whose surface was split into two spatial areas with different microscale smoothness. The context factors were the kind of illumination, the object’s shape, the availability of motion information, the degree of edge blurring, the spatial proportions between the two areas of different smoothness, and the general smoothness level. Detection thresholds were determined using a two-alternative forced choice (2AFC) task implemented in a double random staircase procedure, where the subjects had to indicate for each stimulus whether or not the surface appears to have a spatially uniform material. We found evidence that two different cues are used for this task: luminance differences and differences in highlight properties between areas of different microscale smoothness. While the visual system seems to be highly sensitive in detecting gloss differences based on luminance contrast information, detection thresholds were considerably higher when the judgment was mainly based on differences in highlight features, such as their size, intensity, and sharpness.

Spastin uses its network

Structural Biology AAA ATPases are adenosine triphos phatases associated with diverse cellular activities that have a conserved module of amino acid residues. Spastin is an AAA ATPase protein that severs microtubules. Mutations in spastin cause hereditary spastic paraplegias. Microtubule severing seems to occur when spastin protomers form a hexamer around a polyglutamated tubulin tail and pull the tubulin subunit out of the microtubule lattice. Sandate et al. report a cryo–electron microscopy structure of the spastin hexamer bound to ATP and a polyglutamate peptide. Comparison to an apo-monomer structure shows that ATP binding drives the conformational changes required for oligomerization. Each protomer has three conserved loops. Two loops form a double helical staircase that surrounds the substrate, and the third links the substrate-interacting loops to the nucleotide binding pocket. Thus, ATP and peptide binding establish a network of interactions that stabilize the hexamer and facilitate efficient severing. Nat. Struct. Mol. Biol. 26 , 671 (2019).

Speed Biases With Real-Life Video Clips.

We live almost literally immersed in an artificial visual world, especially motion pictures. In this exploratory study, we asked whether the best speed for reproducing a video is its original, shooting speed. By using adjustment and double staircase methods, we examined speed biases in viewing real-life video clips in three experiments, and assessed their robustness by manipulating visual and auditory factors. With the tested stimuli (short clips of human motion, mixed human-physical motion, physical motion and ego-motion), speed underestimation was the rule rather than the exception, although it depended largely on clip content, ranging on average from 2% (ego-motion) to 32% (physical motion). Manipulating display size or adding arbitrary soundtracks did not modify these speed biases. Estimated speed was not correlated with estimated duration of these same video clips. These results indicate that the sense of speed for real-life video clips can be systematically biased, independently of the impression of elapsed time. Measuring subjective visual tempo may integrate traditional methods that assess time perception: speed biases may be exploited to develop a simple, objective test of reality flow, to be used for example in clinical and developmental contexts. From the perspective of video media, measuring speed biases may help to optimize video reproduction speed and validate “natural” video compression techniques based on sub-threshold temporal squeezing.

Pain hypersensitivity in congenital blindness is associated with faster central processing of C-fibre input.

We have recently shown that visual deprivation from birth exacerbates responses to painful thermal stimuli. However, the mechanisms underlying pain hypersensitivity in congenital blindness are unclear. To study the contribution of Aδ- and C-fibres in pain perception, we measured thresholds and response times to selective C- and Aδ-fibre activation in congenitally blind, late blind and normally sighted participants. Ultrafast constant-temperature heat pulses were delivered to the hand with a CO2 laser using an interleaved adaptive double staircase procedure. Participants were instructed to respond asquickly as possible when detecting a laser-induced sensation. We useda650ms cut-off criterion to distinguish fast Aδ- from slow C-fibre-mediated sensations. Congenitally blind participants showed significantly faster reaction times to C- but not to Aδ-fibre-mediated sensations. In contrast, thresholds for Aδ- and C-fibre stimulation did not differ between groups. Late blind individuals did not differ from sighted controls in any aspect. A follow-up experiment using only suprathreshold stimuli for Aδ- and C-fibre activation confirmed these findings and further showed that congenitally blind individuals detected significantly more C-fibre-mediated stimuli than sighted controls. A decomposition analysis of the reaction times indicated that the faster response times in the congenitally blind are due to more efficient central processing of C-fibre-mediated sensations. The increased sensitivity to painful thermal stimulation in congenital blindness may be due to more efficient central processing of C-fibre-mediated input, which may help to avoid impending dangerous encounters with stimuli that threaten the bodily integrity. WHAT DOES THIS STUDY ADD?: Hypersensitivity to heat pain in congenital blindness is associated with faster responses to C-fibre activation, likely caused by more efficient central processing of C-fibre-mediated input.

Assessment of interlinked double staircase acuity test

PurposeTo compare a novel visual acuity threshold algorithm using a predictive double staircase method with standard ETDRS logMAR chart.MethodsSoftware was written in MATLAB to generate a computerised visual acuity test. The algorithm uses a randomly presented double staircase method, the staircases are interlinked using a prediction of threshold based on each prior response. This reduces test duration and increases accuracy. The screen was calibrated using a Vernier scale and there solution of the test was 0.02 log units. Ten threshold measurements were made for each test, the results expressed as the mean and standard deviation. The test was performed by three observers each with an induced range of refractive errors and compared with the result ofETDRS logMAR acuity using a chart generated with the same screen calibration.ResultsMean stair cased acuities were −0.13, 0.02, 0.22, 0.36, 0.56 log unitsfor 0, 0.5, 1, 1.5 and 2 dioptres of defocus respectively. The mean single letter score logMAR acuities were −0.08, 0.01, 0.17, 0.38, 0.58 log units. The mean error in the stair cased test was 0.02 (SD 0.01) log units forall defocus values. The mean difference between the two tests was −0.01 log units (SD 0.09). Bland‐Altmann plots showed no systematic difference. The mean time to perform the staircased test was 93 seconds (SD 19s).ConclusionsThe interlinked double staircase method gives a fast and accurate assessment of visual acuity which compares well with ETDRS logMAR.Ten threshold measures allow error estimation which is not available in a logMAR test. Other advantages over logMAR include a true resolution of 0.02 log units rather than interpolation and random letter generation with no memory effect.

Specificity of motion discrimination learning even with double training and staircase.

Visual perceptual learning has been traditionally characterized by its specificity. Namely, learning transfers little to many untrained stimulus attributes. This result of specificity is the basis for the inference that perceptual learning takes place in low-level visual areas in the brain. Recently, however, Xiao and colleagues (2008) demonstrated a double training technique that enabled complete transfer of learning in all tasks that were tested. This technique has since been applied to motion direction discrimination learning. Learning along one average direction has been found to transfer completely to a new average direction, along which only dot number discrimination had been trained (J. Y. Zhang & Yang, 2014). In the current study, we first repeated the J. Y. Zhang and Yang (2014) experiment in exact procedure, stimuli, and task. We then continued the double training to examine transfer in longer-term perceptual learning. To our surprise, in both our exact replication attempt and in our longer-term learning study, we could not find complete transfer. In fact, the transfer to the dot number discrimination direction was no greater than to an untrained control direction. We suggest that individual differences and subtle differences in experimental setup between J. Y. Zhang and Yang (2014) and our studies are too strong and common to determine whether or not the new double training technique can bring about complete transfer in motion discrimination learning.

The space of embedded minimal surfaces of fixed genus in a 3-manifold V; Fixed genus

This paper is the fifth and final in a series on embedded minimal surfaces. Following our earlier papers on disks, we prove here two main structure theorems for \itnonsimply connected embedded minimal surfaces of any given fixed genus. The first of these asserts that any such surface without small necks can be obtained by gluing together two oppositely-oriented double spiral staircases. The second gives a pair of pants decomposition of any such surface when there are small necks, cutting the surface along a collection of short curves. After the cutting, we are left with graphical pieces that are defined over a disk with either one or two sub-disks removed (a topological disk with two sub-disks removed is called a pair of pants). Both of these structures occur as different extremes in the two-parameter family of minimal surfaces known as the Riemann examples

Vertical diffusion processes in the Eastern Mediterranean — Black Sea System

The identification and examination of ‘complete’ potential density overturns in CTD profiles, within the framework of SESAME project, are employed to assess vertical eddy diffusivities, mostly in the top 100m of the water column, for a broad area covering the East Mediterranean, the Turkish Straits and the Black Sea. The implementation of this method shows that, mixing induced by mechanical turbulence is enhanced in frontal areas, in the proximity of straits and inside anticyclones; furthermore, that mechanical turbulence is insignificant, down to the scale of CTD resolution, within areas of double diffusive staircases, encountered in deep layers of the water column. Consequently, only laminar theories about double diffusion are applied for assessing diffusivities therein. Susceptibility to different types of double diffusion seems to be related to the interaction of different types of water masses.

Structure-dependent mobility of a dry aqueous foam flowing along two parallel channels

The velocity of a two-dimensional aqueous foam has been measured as it flows through two parallel channels, at a constant overall volumetric flow rate. The flux distribution between the two channels is studied as a function of the ratio of their widths. A peculiar dependence of the velocity ratio on the width ratio is observed when the foam structure in the narrower channel is either single staircase or bamboo. In particular, discontinuities in the velocity ratios are observed at the transitions between double and single staircase and between single staircase and bamboo. A theoretical model accounting for the viscous dissipation at the solid wall and the capillary pressure across a film pinned at the channel outlet predicts the observed non-monotonic evolution of the velocity ratio as a function of the width ratio. It also predicts quantitatively the intermittent temporal evolution of the velocity in the narrower channel when it is so narrow that film pinning at its outlet repeatedly brings the flow to a near stop.

Functional and morphological changes in diabetic macular edema over the course of anti-vascular endothelial growth factor treatment

To evaluate macular morphology and function in diabetic macular edema (DME) over the course of intravitreal anti-vascular endothelial growth factor (VEGF) treatment with Ranibizumab. A consecutive series of 39 study eyes with centre-involving DME were included in this study. In all subjects, best-corrected visual acuity (BCVA) according ETDRS protocol, fluorescein angiography (FA), microperimetric macular sensitivity (MP) and Spectral Domain optical coherence tomography (SD-OCT) cross-sectional scans were obtained before treatment and after 3 monthly applied intravitreal Ranibizumab injections. Six different morphological qualities [IS/OS layer integrity, outer nuclear layer (ONL) cysts, ONL cyst size, inner nuclear layer (INL) cysts, blocking phenomenon and subretinal fluid] were graded of each cross-sectional OCT scan before and over the course of treatment by two experienced graders. Correlation analyses between functional and morphological parameters were obtained. Mean BCVA increased from 26 ± 14 to 33 ± 13 letters after 3 consecutive monthly applied Ranibizumab injections (p < 0.001). Central retinal thickness (CRT) decreased from 504 ± 144 to 387 ± 122 μm (p < 0.001). Over the course of treatment, IS/OS continuity improved (index: 0.56 ± 0.52 to 0.43 ± 0.49, Z = -1.415, p = 0.157), ONL cyst prevalence and size decreased significantly (index: 0.61 ± 0.44 to 0.56 ± 0.35, Z = -3.41, p = 0.001 and 1.75 ± 0.88 to 1.17 ± 1.05, Z = -4.02, p < 0.001), INL cyst prevalence decreased (index: 0.35 ± 0.52 to 0.28 ± 0.52, Z = -1.60, p = 0.109), blocking phenomenon did not change significantly (index: 00.12 ± 0.16 to 0.13 ± 0.15, Z = -0.45, p = 0.656) and subretinal fluid almost disappeared (index: 0.10 ± 0.24 vs. 0.00 ± 0.01, Z = -2.56, p = 0.011). Correlation analyses revealed highest significant correlations between ONL cyst prevalence and their size and CRT as well as BCVA and MP before treatment and over the course of treatment. ONL cysts and their size as morphological parameters correlate with retinal function measured with BCVA and microperimetry before and over the course of anti-VEGF therapy with Ranibizumab in patients with DME.