Apparent Height Research Articles

Vertıcal Internal Brow Suspensıon: A Technıque to Avoıd Lateral Relapse After Endoscopıc Brow Lıft.

Endoscopic brow lift is an integral component of upper face surgical rejuvenation protocols. Lateral relapse is one of the leading causes of dissatisfaction after endoscopic brow lift. This study introduces and evaluates the Vertical Internal Brow Suspension (VIBS), a novel fixation technique designed to prevent lateral brow relapse following endoscopic brow lifts. A retrospective review was conducted on 118 consecutive endoscopic brow lift cases performed by the author between January 2019 and June 2024, using the VIBS technique. Additionally a subgroup of 29 patients who underwent isolated endoscopic brow lifts, with at least one year of follow-up, were included in a quantitative analysis of long-term brow position and forehead height. Significant increases in brow height across all measurement levels (P<0.001) were observed in the quantitative analysis subgroup. No significant change in forehead height was noted (P=0.927). The VIBS technique also beneficially reduced apparent forehead height in patients with initially high foreheads. Frontal suture extrusions (6.8%) and temporary hairloss around scalp incisions (5.1%) were the most common complications observed from the retrospective analysis of 118 patients. The VIBS technique effectively prevents lateral brow relapse, achieving stable lateral brow elevation. It is a safe technique with minor complications. It addresses one of the longstanding challenges of the endoscopic brow lift surgery, representing a valuable advancement in upper face rejuvenation procedures.

Modelling and Analysis of Inhomogeneous Back-to-Back Schottky Junction Diode

Back-to-back Schottky diode (BBSD) is a simple device structure made from Schottky junctions that can be applied in various applications. In modelling and simulating the BBSD, the inhomogeneity of the barrier height at the Schottky interface should be considered. This paper presents device models and simulation result of an inhomogeneous BBSD. Two device models with different current spreading condition are considered. The distribution of the inhomogeneous barrier height is represented by Gaussian distribution. All the computation was done using Python programming software. When the standard deviation of the barrier height increases, the apparent barrier height that influence the electrical characteristic decreased. This is consistent with the reported experimental data. Device model that considers full current spreading showed 37.8% reduction of apparent barrier height at standard deviation of 100 meV. This is greater that the model with no current spreading. The ideality factor showed correlation with the standard deviation of barrier height, particularly when no current spreading is considered. At standard deviation of 100 meV, the ideality factor increased 2.6 %. The obtained non-unity ideality factor is associated to the significant fluctuation in the barrier height. The computed temperature-dependent current curves also showed good agreement with the reported experimental results. The device model can be a convenient tool to investigate the device operation and to validate the method used for extraction of Schottky barrier parameters.

Non-dimensional parameters governing the crashworthy performance of tubes with complex cross-sections

The crashworthiness of thin-walled tubes with various designs under axial compression has been extensively investigated. Despite this, the parameters that govern the performance of tubes and can be applied across different cross-sectional topologies have not hitherto been available. In this paper, twenty types of thin-walled tubes with different cross-sectional shapes (e.g., multi-celled, bi-tubular, and hierarchical square, hexagonal and circular tubes) have been numerically simulated and theoretically analysed. All the tubes are made from identical material and possess identical apparent cross-sectional area, height and mass. Six indicators are employed to characterise the crashworthiness performance of the tubes. Two novel non-dimensional indices, the geometric complexity index (RG) which is the ratio of the total length of solid segments in the cross-section of a tube to that of the square tube, and the topological index (RT) which is the non-dimensional coefficient in the expression of plastic energy dissipation closely related to the types and numbers of the wall junctions in cross-section, are identified for the first time. Both the indices RG and RT are used in a regression analysis of the indicators that characterise the crashworthiness of the tubes. The results reveal that the crashworthiness indicators of the tubes, the mean crushing force (MCF), the specific energy absorption (SEA) and the effectiveness of energy absorption (EEA) do not exclusively vary with RG. Instead, MCF, SEA and EEA are all properly fitted by linear relations with a single non-dimensional parameter ω, which is a simple function of RG and RT, i.e., ω=RT/RG. Increasing the magnitude of ω ultimately improves the crashworthiness of tubes, including enhanced specific energy absorption, effectiveness of energy absorption and crushing force efficiency, while reducing the force fluctuation during the crushing process. Of the tubes studied, the edge-based hierarchical circular tube (EH_C) has the highest SEA of 22.17 J/g, which is 133%, 60% and 41% larger than that of single-celled square, hexagonal and circular tubes, respectively.

#470 Relationship between intraperitoneal volume and intraperitoneal pressure during peritoneal dialysis

Abstract Background and Aims Monitoring intraperitoneal pressure (IPP) has been advocated to quantitate intraperitoneal volume (IPV) during peritoneal dialysis (PD). The aim of this study was to investigate the relationship between IPV and IPP during a short PD dwell. Method Thirteen patients (age 60.2 ± 13.8 years, 5 females, BMI 28.6 ± 7.8 kg/m2) were studied during a 2-hour dwell (2 L dialysate, 2.5% dextrose) in a sitting position. IPP was measured 4x per minute by a pressure sensor integrated in the Liberty Cycler (Fresenius Medical Care, Waltham, MA, USA). Segmental abdominal bioimpedance (Hydra 4200, Xitron Technologies, San Diego, CA, USA) was done concurrently to measure IPV. Serum and dialysate creatinine and glucose concentrations were measured before and after the dwell. Dialysate density (ρ) was measured by a handheld density meter (Mettler-Toledo, Columbus, OH USA). Ultrafiltration volume (UFV) was recorded by the Liberty Cycler. A simple physical model (IPP = ρ × h × g) was used to explore the relationship between IPP and IPV (Fig. 1). Based on the model, a change in IPP (ΔIPP) depends on the change of apparent dialysate height (Δh) and dialysate density (Δρ); g is the gravity constant. The apparent cross-sectional area (A) of the peritoneal cavity was calculated as IPV/h. Results Average UFV was 0.31 ± 0.25 L (range 0.03 to 1.03 L). During the dwell, IPP decreased in 12 patients (UFV 0.03 to 0.49 L; Fig. 2) and increased in one (UFV 1.03 L). The IPP decrease (−3.81 ± 2.78 cmH2O; −21.2 ± 18%, p &amp;lt; 0.01) was accompanied by a decrease of apparent h (−0.04 ± 0.03 m; −20.9 ± 18.5%, p &amp;lt; 0.01) and ρ (−3.41 ± 0.56 kg/m3; −0.34 ± 0.06%, p &amp;lt; 0.0001). In patients with a decrease in IPP, the apparent dialysate h decreased from 0.19 ± 0.04 to 0.14 ± 0.04 m, and the apparent A increased from 107.8 ± 23 to 154.7 ± 34 cm2. In the patient with IPP increase, the apparent h increase from 0.14 to 0.18 m, and the apparent A from 138.4 to 164.6 cm2. ΔIPP inversely correlated with Δρ (Fig. 3) and UFV (Fig. 4). Moreover, ΔIPP correlated with D/P creatinine (Fig. 5) and with D/D0 glucose (Fig. 6). Conclusion In this proof-of-concept study, a simple physical model was used to explore the relationship between IPP and IPV. Contrary to our expectation, we found that IPP declines in most patients during the dwell. Decrease in IPP is related to increase in the apparent cross-sectional area of the peritoneal cavity. We hypothesize that during the dwell additional spaces of the peritoneal cavity become accessible to IPV. To what extent this opening of peritoneal space is associated with membrane characteristics warrants further studies.

ANÁLISIS DEL CRECIMIENTO DE Carica papaya L. BAJO INFECCIÓN POR PRSV-P

&lt;p&gt;&lt;strong&gt;Background.&lt;/strong&gt; Papaya (&lt;em&gt;Carica papaya&lt;/em&gt; L.) is cultivated in tropical and subtropical regions of the world for its nutritious and healthy fruits intended mainly for fresh consumption. Mexico was the world's leading papaya exporter in 2020 with 167,500 t. &lt;em&gt;C. papaya&lt;/em&gt; is attacked by several viral diseases, the ring spot virus (PRSV-P) is the one that causes the most damage to the crop and the greatest production losses. &lt;strong&gt;Objective.&lt;/strong&gt; To establish the phenology of a &lt;em&gt;Carica papaya&lt;/em&gt; L. ‘Maradol Roja’ population infected with PRSV-P, to quantify its growth, and to relate its phenological steps with the accumulated degree days (DD). &lt;strong&gt;Methodology.&lt;/strong&gt; The emissions of leaves, flower buds, flowers and fruits, apparent height of the plant, stem diameter and biomass were evaluated, based on the DD accumulated during the growth cycle. &lt;strong&gt;Results.&lt;/strong&gt; The growth cycle is divided into nine phenological stages, where the leaf or flower bud formation requires ≈ 18 DD. In plants, the number of leaves is approximately equal to the number of flower buds. However, the number of ripe fruits is variable due to the adverse conditions that can occur throughout the growth period. To some extent, the roots typically present two growth peaks, although the available moisture in the soil could change this pattern. The apparent height of the plant and the stem diameter present a double sigmoid growth curve, with a maximum apparent height of 180 cm, and a diameter at the base of 11 cm. &lt;strong&gt;Implications.&lt;/strong&gt; The infection by PRSV-P reduced the productivity and commercial quality of the fruits. &lt;strong&gt;Conclusions.&lt;/strong&gt; PRSV-P infection reduced apparent height, stem diameter, number of leaves, flowers, and fruits, decrease in biomass gain, and shortened life cycle of plants.&lt;/p&gt;

Predictive Value of Cervical Degenerative Quantitative Scoring System on Postoperative Disc Height Loss After Cervical Disc Replacement.

A retrospective study. In this study, a cervical degenerative quantitative scoring system was used to identify the risk factors for disc height loss after cervical disc replacement (CDR) and to verify their accuracy. Disc height loss after CDR is drawing much attention. Preoperative cervical degeneration has been proven related to postoperative disc height loss but lacked quantitative verification. A total of 160 patients who underwent CDR with the Prestige-LP disc at our hospital between January 2011 and December 2016 were retrospectively reviewed. Disc height loss was defined as a reduction of more than 2 mm from postoperative to the final follow-up. A quantitative scoring system was used to evaluate preoperative degeneration on radiographs. Multivariate logistic regression was applied to determine predictive factors and calculate the logistic regression formula. Moreover, receiver operating characteristic curve analysis was conducted to obtain the optimal cutoff value and the area under the receiver operating characteristic curve [areas under the curve (AUC)]. Study subjects had a mean age of 43.51 ± 8.51 years, with a mean follow-up time of 60.14 ± 12.75 months. The overall incidence rate of disc height loss was 65.62%. Multivariate logistic regression analysis showed that endplate sclerosis ( P = 0.000) and low preoperative disc height ( P = 0.000) were independent risk factors for postoperative disc height loss. In addition, the calculated optimal cutoff point was 1 point of endplate sclerosis (AUC = 0.768) and 4.5 mm of preoperative disc height (AUC = 0.795). The regression formula established by multivariate logistic regression analysis was composed of preoperative disc height (odds ratio: 2.995, P = 0.000) and endplate sclerosis (odds ratio: 18.131, P = 0.000), with an AUC of 0.879. Our findings suggest that a comprehensive preoperative assessment is essential when patients with apparent endplate sclerosis and low preoperative disc height are being considered for CDR.

Evaluation of Surface Structure and Morphological Phenomena of Caucasian Virgin Hair with Atomic Force Microscopy.

Background and Objectives: Atomic force microscopy (AFM) as a type of scanning microscopy (SPM), which has a resolution of fractions of a nanometer on the atomic scale, is widely used in materials science. To date, research using AFM in medicine has focused on neurodegenerative diseases, osteoporosis, cancer tumors, cell receptors, proteins and the DNA mismatch repair (MMR) system. Only a few small studies of hair imaging have been conducted, mostly in biotechnology or cosmetology. Thanks to the possibilities offered by AFM imaging, dermatologists can non-invasively assess the condition of hair and its possible disorders. Our goal was to capture images and microscopically analyze morphological changes in the surface of healthy hair. Materials and Methods: In this study, three to five hairs were collected from each person. Each hair was examined at nine locations (0.5; 1.0; 1.5; 2.0; 3.5; 4.5; 5.5; 6.5 and 7.0 cm from the root). At least 4 images (4-10 images) were taken at each of the 9 locations. A total of 496 photos were taken and analyzed. Metric measurements of hair scales, such as apparent length, width and scale step height, were taken. Results: This publication presents the changes occurring in hair during the natural delamination process. In addition, morphoological changes visualized on the surface of healthy hair (pitting, oval indentations, rod-shaped macro-fibrillar elements, globules, scratches, wavy edge) are presented. A quantitative analysis of the structures found was carried out. Conclusions: The findings of this study can be used in further research and work related to the subject of human hair. They can serve as a reference for research on scalp and hair diseases, as well as hair care.

Inaccurate but predictable: Vocal-tract length estimation and gender stereotypes in height perception

Research suggests human listeners are not very accurate in assessing the size of adults from their speech, though they appear to be consistent in their judgments across listeners. Two experiments were conducted to investigate the importance of the higher formants for providing consistent height judgments, how consistent these height judgments are across replications, and the role of f0 and social knowledge in maintaining the stability of apparent speaker height judgments. Listeners were presented with syllables produced by 30 adult male and female speakers, and were asked to identify the word, the gender of the speaker, and the height of the speaker. In a second experiment, listeners were presented with voiced and (synthetic) whispered speech and asked to provide the same responses. Results indicate that speakers use acoustic cues in largely predictable ways, leading to consistent apparent height judgments when averaged across listeners. However, the behavior of individual listeners is unpredictable, and the accuracy of apparent height judgments with respect to veridical heights is low. Finally, results suggest that non-acoustic social knowledge regarding the expected sizes of adult males and females play an important role in the determination of apparent height from speech.

The structure-giving role of Rb+ ions for water-ice nanoislands supported on Cu(111).

We characterize the effect of rubidium ions on water-ice nanoislands in terms of area, fractal dimension, and apparent height by low-temperature scanning tunneling microscopy. Water nanoislands on the pristine Cu(111) surface are compared to those at similar coverage on a Rb+ pre-covered Cu(111) surface to reveal the structure-giving effect of Rb+. The presence of Rb+ induces changes in the island shape, and hence, the water network, without affecting the nanoisland volume. The broad area distribution shifts to larger values while the height decreases from three bilayers to one or two bilayers. The nanoislands on the Rb+ pre-covered surface are also more compact, reflected in a shift in the fractal dimension distribution. We relate the changes to a weakening of the hydrogen-bond network by Rb+.

Quality-controlled meteorological datasets from SIGMA automatic weather stations in northwest Greenland, 2012–2020

Abstract. In situ meteorological data are essential to better understand ongoing environmental changes in the Arctic. Here, we present a dataset of quality-controlled meteorological observations from two automatic weather stations in northwest Greenland from July 2012 to the end of August 2020. The stations were installed in the accumulation area on the Greenland Ice Sheet (SIGMA-A site, 1490 m a.s.l.) and near the equilibrium line of the Qaanaaq Ice Cap (SIGMA-B site, 944 m a.s.l.). We describe the two-step sequence of quality-controlling procedures that we used to create increasingly reliable datasets by masking erroneous data records. Those datasets are archived in the Arctic Data archive System (ADS) (SIGMA-A – https://doi.org/10.17592/001.2022041303, Nishimura et al., 2023f; SIGMA-B – https://doi.org/10.17592/001.2022041306, Nishimura et al., 2023c). We analyzed the resulting 2012–2020 time series of air temperature, surface height, and surface albedo and histograms of longwave radiation (a proxy of cloudiness). We found that surface height increased, and no significant albedo decline in summer was observed at the SIGMA-A site. In contrast, high air temperatures and frequent clear-sky conditions in the summers of 2015, 2019, and 2020 at the SIGMA-B site caused significant albedo and surface lowering. Therefore, it appears that these weather condition differences led to the apparent surface height decrease at the SIGMA-B site but not at the SIGMA-A site. We anticipate that this quality-controlling method and these datasets will aid in climate studies of northwest Greenland and will contribute to the advancement of broader polar climate studies.

Clinical success of guided tissue regeneration for treating vertical bone and furcation defects in dogs.

This study evaluated the clinical success rate of guided tissue regeneration (GTR) for treating advanced periodontal disease in a large canine cohort. A total of 112 GTR procedures performed from 2003-2021 were retrospectively evaluated, including pre- and post-treatment (3-12 months) periodontal probing depths of 104 treated teeth, dental radiographs of 73 treated teeth, and both diagnostic modalities in 64 treated teeth. Probing depth, radiographically apparent bone height, bone graft material, barrier membrane material, and tooth extraction adjacent to the GTR site were investigated as factors affecting success. Vertical bone defects were evaluated separately from furcation defects. GTR was clinically successful, defined as objective improvement in probing depth, objective decrease in radiographic vertical bone defect, and subjective radiographic gain in bone height in 90.3% of vertical bone defects. Success was significantly associated with the magnitude of initial probing depth and the type of barrier membrane used. GTR was clinically successful, defined as objective improvement in furcation probing and subjective radiographic improvement of the bone in the furcation in 22.2% of furcation defects. When F3 lesions were excluded, GTR was successful in 64.3% of furcation defects. GTR is an appropriate treatment to maintain teeth in the oral cavity of dogs with proper client counseling and patient selection, but it is most likely to be successful in vertical defects.

Insights into factors that affect non-Arrhenius migration of a simulated incoherent Σ3 grain boundary

Non-Arrhenius grain boundary migration, sometimes referred to as antithermal migration where temperature and GB velocity values are inversely related to each other, is examined in an incoherent twin Σ3 [111] 60° (11 8 5) nickel grain boundary. Molecular dynamics is used to simulate migration and examine the effect of various factors on the migration, including interatomic potential, system size, driving force, and variation of atomic grain boundary structure. A classical model for grain boundary migration, in its unsimplified form, is used to analyze the results. The grain boundaries exhibit migration mechanisms with very low apparent barrier heights to migration. As a result, the boundaries migrate quickly but exhibit a velocity saturation similar to that of dislocations. The various interatomic potentials exhibit different migration velocities, but their similarities suggest they all predict similar overall behaviors of migration. The variation of atomic structure in the same incoherent twin grain boundary leads to diverse behaviors with barrier heights that vary from non-Arrhenius to Arrhenius migration. Facet nucleation is confirmed not to be a requirement for this boundary based on an examination of simulation cell size; however, the presence and/or interaction between numerous facets does suggest a slowing and increased barrier height to migration for larger boundaries.

New Insights Into the Role of Atmospheric Transport and Mixing on Column and Surface Concentrations of NO2 at a Coastal Urban Site

AbstractWe use a multi‐year record of Pandora‐derived NO2 total column abundance in Boston to examine the influence of atmospheric transport on column NO2 and its surface concentrations during the warm season in a coastal urban environment. We derive tropospheric NO2 estimates from the total column with a measurement‐model fusion approach using near‐real‐time estimates of stratospheric NO2 from NASA's Goddard Earth Observing System Composition Forecast model system and find the average influence of stratospheric NO2 at this urban site can be 30%–70% depending on season and time of day. Sea breeze days tend to exhibit rapid temporal variability in the column that which can go in the opposite direction of changes in surface NO2 concentrations. By comparing tropospheric NO2 with surface concentrations, we constrain the role of boundary layer entrainment processes in the evolution of surface NO2 concentrations, while highlighting the value of column measurements in identifying sea breeze frontal dynamics. We estimate an apparent equal mixing layer height of NO2 and infer that surface NOx emissions remain concentrated near the surface regardless of atmospheric stability regime. When comparing the Pandora‐ to TROPOMI‐derived column NO2 measurements, we find that sea breeze days present a unique challenge likely due to higher spatial heterogeneity in NO2 and the meteorology involved that is not well represented in retrieval inputs. Our observations provide new insights into column and surface variability of NO2 which will be relevant to interpreting geostationary observations, especially in coastal urban locations.

Rapid Rotation of an Erupting Prominence and the Associated Coronal Mass Ejection on 13 May 2013

In this paper, we report the multiwavelength observations of an erupting prominence and the associated coronal mass ejection (CME) on 13 May 2013. The event occurs behind the western limb in the field of view of the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO) spacecraft. The prominence is supported by a highly twisted magnetic flux rope and shows rapid rotation in the counterclockwise direction during the rising motion. The rotation of the prominence lasts for ∼ 47 minutes. The average period, angular speed, and linear speed are ∼ 806 sec, ∼ 0.46 rad min−1, and ∼ 355 km s−1, respectively. The total twist angle reaches ∼ 7 $\pi$ , which is considerably larger than the threshold for kink instability. Writhing motion during 17:42 – 17:46 UT is clearly observed by SWAP in 174 Å and Extreme-UltraViolet Imager (EUVI) on board the behind Solar Terrestrial Relations Observatory (STEREO) spacecraft in 304 Å after reaching an apparent height of ∼ 405 Mm. Therefore, the prominence eruption is most probably triggered by kink instability. A pair of conjugate flare ribbons and post-flare loops are created and observed by STA/EUVI. The onset time of writhing motion is consistent with the commencement of the impulsive phase of the related flare. The 3D morphology and positions of the associated CME are derived using the graduated cylindrical shell (GCS) modeling. The kinetic evolution of the reconstructed CME is divided into a slow-rise phase (∼ 330 km s−1) and a fast-rise phase (∼ 1005 km s−1) by the writhing motion. The edge-on angular width of the CME is a constant (60∘), while the face-on angular width increases from 96∘ to 114∘, indicating a lateral expansion. The latitude of the CME source region decreases slightly from ∼ 18∘ to ∼ 13∘, implying an equatorward deflection during propagation.

On the Scale‐Dependence of Fault Surface Roughness

AbstractDefining roughness as the ratio of height to length, the standard approach to characterize amplitudes of single fault, joint and fracture surfaces is to measure average height as a function of profile length. Empirically, this roughness depends strongly on scale. The ratio is approximately 0.01 at a few mm but 10× smaller at a few tens of meters. Surfaces are rougher at small scales. However, these conclusions are metric‐dependent. If instead height is averaged over wavelength, roughness is nearly Brown spatial noise, having almost scale‐independent apparent surface height to wavelength ratio. The small deviation from scale‐independence is of the opposite sense than found using the standard metric; surfaces are slightly rougher at long wavelengths. Some natural surfaces may be Brownian within the measurement uncertainties. These contradictions are curiosities of surfaces that have Hurst exponents between 0.5 and 1, as natural fault surfaces do. The wavelength‐based analysis of roughness and how it changes with scale are straight‐forward; a normalized Fourier transform approximately preserves amplitude and its scale dependence in the wavelength domain. Among the conclusions from reconsideration of scale dependence are that the scale dependence is weak and much smaller than that of other fault and shear zone properties. Background and aftershock seismicity, jogs and step‐overs indicate strong localization (smoothing) with slip and scale. The lack of strong scale dependence to surface roughness suggests it is not the dominant control on brittle shear zone evolution.

Mechanoelastic simulations of monolayer lattices of spin crossover molecules on a substrate

In this paper, we discuss in the framework of a mechanoelastic model the electronic and mechanical behavior of a single layer of spin crossover molecules self-organized on a substrate. We consider the molecules situated in a face-centered-cubic structure interacting in between and with sites in the substrate by the way of connecting springs with given elastic constants. The main experimental results are reproduced, i.e., typical thermal transitions with their incompleteness of the hysteresis loop, residual fractions after low-temperature relaxations, cooperativity, or kinetic features. However, we prove that the simple model, implying fixed neighbors on the substrate for every spin crossover molecule, leads in some cases to unphysical situations, corresponding to unexpected large curvatures of the spin crossover layer. Therefore, to go further, we allow every spin crossover molecule to change its adsorption site on the substrate at every moment, by connecting to the closest molecules on the substrate. This approach, corroborated with the use of different densities of the sites on the substrate, allows us to simulate further experimental observations, such as the appearance of cracks inside the layer or periodic arrangements of apparent heights of spin crossover molecules on the layer leading to moir\'e patterns, for which experimental data are also provided.

Electrical properties of Cu/Pd2Si Schottky contacts to AlGaN/GaN-on-Si HEMT heterostructures

In this study, we analyze gold-free Cu/Pd2Si Schottky contacts to AlGaN/GaN-on-Si HEMT (high electron mobility transistor) heterostructures. The silicide layers are fabricated through magnetron sputtering deposition using a stoichiometric Pd2Si target and are subjected to post-gate annealing at different temperatures. After annealing at 500 °C the leakage currents of the planar diodes are reduced below 3.2 mA/cm2. The microstructures of the diodes are analyzed through transmission electron microscopy (TEM). The post-gate annealing increases lateral dimensions of silicide grains. The electrical properties of the contacts are determined by performing temperature-dependent current-voltage (I-V-T) measurements. The forward current exhibits a specific voltage dependence, which is interpreted based on the two-diode model, reflecting the properties of the Pd2Si/heterostructure interface along with those of the heterostructure itself. The model is fitted to extract the parameters of the Schottky contacts. The barrier height of 0.91 eV and ideality factor n = 1.5 are obtained after post-gate annealing at 500 °C. The effects of post-gate annealing on the forward conduction and leakage mechanisms are then discussed. A simple method is proposed to estimate the polarization charge density, which is required to calculate the electric fields in the heterostructure in the reverse bias. It is observed that post-gate annealing affects the I-V characteristics, likely by reducing the density of the unintentional donors and trap states, leading to an increase in the apparent barrier height along with a reduction in the density of defects contributing to the leakage current.

Effect of surface preparation on PtSe2 crystal surface morphology

Transition metal dichalcogenides, a new class of layered materials, have recently been deemed as an excellent material platform for the further development of microelectronics. Contrary to the general trend, which is geared toward layers, we focus our attention on basic research regarding bulk PtSe2. The justification for this approach is based on the fact that some research (e.g., on the impact of the doping process on the material’s properties) can be performed on the bulk crystal. We believe that the conclusions drawn from our approximation can be extrapolated to thin films and monolayers. In this paper, we present a morphological study of the influence of the surface preparation procedure on the PtSe2 substrate. We show that mechanical exfoliation is one possible way to achieve a clean PtSe2 surface. However, STM measurements revealed that this process is insufficient to achieve an atomically clean surface. Subsequent additional annealing under UHV conditions led to an improved surface morphology by reducing the number of mobile PtSe2 flakes as well as the density of small surface clusters. Finally, STM measurements show other interesting surface structures, such as cracks, bulges, and flakes with heights lower than the apparent height typical of a PtSe2 monolayer.

Second-order texture gratings produce overestimation of height in depictions of rectangles and steps

The horizontal-vertical illusion (HVI) has been proposed as a method to increase the perceived height of steps, increase toe clearance and prevent falls. High contrast vertical stripes are placed on the step riser abutting a horizontal edge-highlighter creating ‘T’ junctions which are thought to promote the illusion. Various configurations of the HVI were tested including luminance gratings (L) and second-order modulations of contrast (CM), spatial frequency (FM) and orientation (OM). Observers were asked to compare the apparent height of gratings with that of either filled, unmodulated rectangles or unfilled rectangles. Rectangles were presented alone or as part of a step with a highlighter. In some conditions highlighters matched the properties of the grating; in others or not. In one critical experiment, the HVI was compared for steps with highlighters that were separated from the riser by a thin line and those where the risers and highlighters were continuous. All gratings except FM appeared taller when presented in the step configuration with a continuous, matching highlighter. This effect was greatly reduced when a thin line separated the grating from the highlighter and abolished for mis-matched highlighters and risers. In the rectangle conditions, all cues appeared taller than blank rectangles and L and CM appeared taller than filled-unmodulated rectangles. In conclusion, second-order cues may be useful for inducing the HVI onto steps. However, the ability of vertical stripes and edge-highlighters to accentuate perceived step height may be due to aggregation of the highlighter into the grating rather than the normal horizontal-vertical illusion.

COMPUTED TOMOGRAPHY FOR MEASURING BODY FAT RESERVES IN THE THREATENED MOJAVE DESERT TORTOISE (GOPHERUS AGASSIZII).

Noninvasive methods for measuring fat reserves in both captive and free-ranging animals are important for monitoring individual and population health, but chelonian anatomy and physiology present challenges to accurate measurements. Standard field-based methods for assessing body condition in Mojave desert tortoises (Gopherus agassizii) involve the qualitative body condition score, which relies on the apparent height of the temporalis muscle relative to the sagittal crest (in addition to other characteristics) and quantitative body condition indices that measure relative mass at size. However, it is unclear how these metrics relate to body fat reserves in this species. The aims of this study were to (1) describe the use of noninvasive computed tomography in measuring body fat volume of Mojave desert tortoises, (2) describe the location of fat reserves, (3) investigate relationships between fat reserves and body condition score and body condition index, and (4) explore whether relative temporalis muscle depth, measured via computed tomography, correlates with body condition score. Body condition scores were assessed for eight captive Mojave desert tortoises prior to euthanasia, and computed tomography was performed postmortem to quantify fat volume and measure temporalis muscle depth. At necropsy, the distribution of fat was documented. Fat volume calculated by computed tomography ranged from 2.83 to 145.38 cm3 (0.07-2.5% body volume). Neither qualitative body condition score nor quantitative body condition index was correlated with fat volume. Bladder content did not compromise body condition index. Body condition score was not correlated with relative temporalis muscle depth. Computed tomography is a noninvasive method for successfully identifying fat reserves and estimating total fat volume in Mojave desert tortoises. The lack of a relationship between computed tomography-determined metrics and commonly used body condition metrics indicates that computed tomography fills a critical gap in the health assessment tool kit for captive and free-ranging Mojave desert tortoises.