Initial Profile Research Articles

This Month in Adult Urology.

This Month in Adult Urology.

Orbital evolution of satellite galaxies in self-interacting dark matter models

Dark matter self-interactions can leave distinctive signatures on the properties of satellite galaxies around Milky Way--like hosts through their impact on tidal stripping, ram pressure, and gravothermal collapse. We delineate the regions of self-interacting dark matter parameter space---specified by interaction cross section and a velocity scale---where each of these effects dominates and show how the relative mass loss depends on the satellite's initial mass, density profile, and orbit. We obtain novel, conservative constraints in this parameter space using Milky Way satellite galaxies with notably high central densities and small pericenter distances. Our results for self-interacting dark matter models, in combination with constraints from clusters of galaxies, favor either velocity-dependent cross sections that lead to gravothermal core collapse in the densest satellites or small cross sections which more closely resemble cold and collisionless dark matter.

Perturbative analysis of low-frequency instabilities in high-field ST40 experiments

Linear and nonlinear perturbative analyses of low-frequency instabilities are presented for ST40 spherical torus high field plasmas, with simultaneous neutral beam heating due to two tangential sources at 25 keV and 55 keV. Initial plasma profiles on which the TRANSP and NUBEAM codes were based were obtained using an integrated analysis of several diagnostics including line-of-sight integrated and volume average measurements, as well as limited profile information from a charge-exchange-recombination spectrometer. Magnetohydrodynamics (MHD) analysis using the NOVA/NOVA-K codes suggests that the modes in the experiments are core-localized n = 1 eigenmodes with mixed acoustic and electromagnetic Alfvénic polarization. The global transport combined with the perturbative mode analysis indicates that there is greater tendency for bursty chirping response as the level of background micro-turbulence decreases in time and those predictions are shown to be consistent with the experimental data. This finding is interpreted in terms of the suppression of coherent phase-space structures that support chirping when the resonant fast ion dynamics is dominated by frequent stochastic, orbit-decorrelating events.

Estimating the asymptotic characteristic time scales for diffusion-controlled drug release systems using partially sampled data

Drug release experiments and numerical simulations only give access to partial release data (i.e., within a finite time range t∈[0,tf]). In this article, we propose fitting-based procedures to estimate the asymptotic time scales of the release process, namely the global relaxation time τ∗ and the longest (or terminal) relaxation time τ0, from partially sampled data of diffusion-controlled drug release systems. We test these procedures on both synthetic and experimental data using, as an example, the well-known Weibull function. Our results show that the Weibull function must be used with great care because the values of the fitting parameters can vary significantly depending on the ratio tf/τ0. Beyond their practical simplicity, the usefulness of our procedures is evidenced by the fact that: (1) the initial loading profile does not need to be known and (2) the chosen fitting function does not require any physical basis. These two advantages allow us to determine the diffusion coefficient of the molecules directly from the characteristic time τ0.

Simulated Trapping of Solar Energetic Protons for the 8–10 March 2012 Geomagnetic Storm: Impact on Inner Zone Protons as Measured by Van Allen Probes

AbstractSolar energetic protons (SEPs) have been shown to contribute significantly to the inner zone trapped proton population for energies <100 MeV and L > 1.3 (Selesnick et al., 2007, https://doi.org/10.1029/2006sw000275). The Relativistic Electron Proton Telescope (REPT) on the Van Allen Probes launched 30 August 2012 observed a double‐peaked (in L) inner zone population throughout the 7‐year lifetime of the mission. It has been proposed that a strong SEP event accompanied by a CME‐shock in early March 2012 provided the SEP source for the higher L trapped proton population, which then diffused radially inward to be observed by REPT at L ∼ 2. Here, we follow trajectories of SEP protons launched isotropically from a sphere at 7 Re in 15 s cadence fields from an Lyon‐Fedder‐Mobarry coupled to Rice Convection Model global magnetohydrodynamic (MHD) simulation driven by measured upstream solar wind parameters. The timescale of the interplanetary shock arrival is captured, launching a magnetosonic impulse propagating azimuthally along the dawn and dusk flanks inside the magnetosphere, shown previously to produce SEP trapping. The MHD‐test particle simulation uses Geostationary Operational Environmental Satellite (GOES) proton energy spectra to weight the initial radial profile required for the radial diffusion calculation over the following 2 years. GOES proton measurements also provide a dynamic outer boundary condition for radial diffusion. A direct comparison with REPT measurements 20 months following the trapping event in March 2012 supports this novel combination of short‐term and long‐term evolution of the newly trapped protons.

Unsteady thermal transport in an instantly heated semi-infinite free end Hooke chain

We consider unsteady ballistic heat transport in a semi-infinite Hooke chain with free end and arbitrary initial temperature profile. An analytical description of the evolution of the kinetic temperature is proposed in both discrete (exact) and continuum (approximate) formulations. By comparison of the discrete and continuum descriptions of kinetic temperature field, we reveal some restrictions to the latter. Specifically, the far-field kinetic temperature is well described by the continuum solution, which, however, deviates near and at the free end (boundary). We show analytically that, after thermal wave reflects from the boundary, the discrete solution for the kinetic temperature undergoes a jump near the free end. A comparison of the descriptions of heat propagation in the semi-infinite and infinite Hooke chains is presented. Results of the current paper are expected to provide insight into non-stationary heat transport in the semi-infinite lattices.

Numerical simulation of thermal stratification in Lake Qiandaohu using an improved WRF-Lake model

Lake thermal stratification is important for regulating lake environments and ecosystems and is sensitive to climate change and human activity. However, numerical simulation of coupled hydrodynamics and heat transfer processes in deep lakes using one-dimensional lake models remains challenging because of the insufficient representation of key parameters. In this study, Lake Qiandaohu, a deep and warm monomictic reservoir, was used as an example to investigate thermal stratification via an improved parameterization scheme of the Weather Research and Forecast (WRF)-Lake. A comparison with in situ observations demonstrated that the default WRF-Lake model was able to simulate well the seasonal variation of the lake thermal structure. However, the simulations exhibited cold biases in lake surface water temperature (LSWT) throughout the year while generating weaker stratification in summer, thereby leading to an earlier cooling period in autumn. With an improved parameterization (i.e., via determination of initial lake water temperature profiles, light extinction coefficients, eddy diffusion coefficients and surface roughness lengths), the modified WRF-Lake model was able to better simulate LSWT and thermal stratification. Critically, employing realistic initial conditions for lake water temperature is essential for producing realistic hypolimnetic water temperatures. The use of time-dependent light extinction coefficients resulted in a deep thermocline and warm LSWT. Enlarging eddy diffusivity led to stronger mixing in summer and further influenced autumn cooling. The parameterized surface roughness lengths mitigated the excessive turbulent heat loss at the lake surface, improved the model performance in simulating LSWT, and generated a warm mixed layer. This study provides guidance on model parameterization for simulating the thermal structure of deep lakes and advances our understanding of the strength and revolution of lake thermal stratification under seasonal changes.

Going solo and feeling smart? An exploratory study on shoppers' time valuation and cultural perception

PurposeThe advent of digitalization and the trend of social distancing coincide with the individualized lifestyle that is emerging among contemporary shoppers. This study explores the unique market of “smart solo shoppers”. Two empirical studies are conducted, which aim to identify the major dimensions of multi-channel shopping activities that are engaged by the shoppers (Study 1, n = 64) and to differentiate the shoppers' valuation of time invested in the distinct dimensions under different cultural influences (Study 2, n = 519).Design/methodology/approachA survey questionnaire is used for data collection, and data are analyzed using structural equation modeling.FindingsResults reveal that the shopping activities converge into four principal dimensions: offline shopping, online shopping, post-shopping delivery and product return activities. Shoppers who perceive offline shopping activities as a time burden and online shopping and delivery activities as venues of value creation are more strongly self-identified as smart solo shoppers. Furthermore, smart solo shoppers who are under a strong influence of individualistic culture are found to spend time on multi-channel shopping to make the right purchase the first time, whereas shoppers perceiving being in a weak individualistic culture prefer to engage online channels while being prepared to return the unwanted purchases.Originality/valueThis study highlights an emerging research field in the nexus of solo consumption and smart shopping. Emphasizing the utility-driven and ego-expressive nature of smart solo shoppers, the authors provide an initial profile of these shoppers based on their time-valuation patterns and the contextual impacts of individualistic culture.

On the cone-to-jet transition region and its significance in electrospray propulsion

A novel method for identifying the cone-to-jet transition region is proposed to characterize the electrospray dynamics, and thus the Taylor cone, a fundamental principle of ion extraction from the tip of the Taylor cone in an electric field to produce μN thrust for nanosatellites' application. A numerical model is developed and validated against the droplet's diameter with a proper characterization of the cone-to-jet transition region based on the hydrodynamic pressure gradient at the cone-jet axis. The results show that the cone-to-jet transition region is reduced when the electric potential increases and the flow rate decreases. Moreover, the current density is found to be higher for the lower flow rate and large electric potential. Interestingly, the current density at the jet axis increases significantly at the flow rate of 1 cc/hr. This implies that below a certain droplet diameter, the current density carried by the jet interface is completely migrated into the jet, and the substantial change in the current density occurs within the cone-to-jet transition region. When comparing the current density along the jet axis, the small flow rate and large electric potential carry the maximum current density at the jet interface. The identification of cone-to-jet transition region is central in modeling the ion beam trajectory via initial current density profile required for particle-in-cell calculation for assuring the performance of a field emission electric propulsion thruster.

Mantle mineralogy limits to rocky planet water inventories

ABSTRACT Nominally anhydrous minerals in rocky planet mantles can sequester multiple Earth-oceans’ worth of water. Mantle water storage capacities therefore provide an important constraint on planet water inventories. Here we predict silicate mantle water capacities from the thermodynamically-limited solubility of water in their constituent minerals. We report the variability of upper mantle and bulk mantle water capacities due to (i) host star refractory element abundances that set mantle mineralogy, (ii) realistic mantle temperature scenarios, and (iii) planet mass. We find that transition zone minerals almost unfailingly dominate the water capacity of the mantle for planets of up to ∼1.5 Earth masses, possibly creating a bottleneck to deep water transport, although the transition zone water capacity discontinuity is less pronounced at lower Mg/Si. The pressure of the ringwoodite-perovskite phase boundary defining the lower mantle is roughly constant, so the contribution of the upper mantle reservoir becomes less important for larger planets. If perovskite and postperovskite are relatively dry, then increasingly massive rocky planets would have increasingly smaller fractional interior water capacities. In practice, our results represent initial water concentration profiles in planetary mantles where their primordial magma oceans are water-saturated. This work is a step towards understanding planetary deep water cycling, thermal evolution as mediated by rheology and melting, and the frequency of ocean planets.

Large deviations of a tracer position in the dense and the dilute limits of single-file diffusion.

We apply the macroscopic fluctuation theory to analyze the long-time statistics of the position of a tracer in the dense and the dilute limits of diffusive single-file systems. Our explicit results are about the corresponding large deviation functions for an initial step density profile with the fluctuating (annealed) and the fixed (quenched) initial conditions. These hydrodynamic results are applicable for a general single-file system and they agree with recent exact results obtained by microscopic solutions for specific model systems.

Effects of initial ion velocity, magnetic field and plasma density profiles in simulating the plasma plume in a Hall thruster

Effects of initial ion velocity, magnetic field and plasma density profiles in simulating the plasma plume in a Hall thruster

Systemic factors associated with 10-year glaucoma progression in South Korean population: a single center study based on electronic medical records

Glaucoma is a multifactorial disease where various systemic features are involved in the progression of the disease. Based on initial systemic profiles in electronic medical records, this study aimed to develop a model predicting factors of long-term rapid retinal nerve fiber layer (RNFL) thinning over 5 years in 505 patients with primary open-angle glaucoma. Eyes with faster or slower RNFL thinning were stratified using a decision tree model, and systemic and ophthalmic data were incorporated into the models based on random forest and permutation methods, with the models interpreted by Shapley additive explanation plots (SHAP). According to the decision tree, a higher lymphocyte ratio (> 34.65%) was the most important systemic variable discriminating faster or slower RNFL thinning. Higher mean corpuscular hemoglobin (> 32.05 pg) and alkaline phosphatase (> 88.0 IU/L) concentrations were distinguishing factors in the eyes with lymphocyte ratios > 34.65% and < 34.65%, respectively. SHAP demonstrated larger baseline RNFL thickness, greater fluctuation of intraocular pressure (IOP), and higher maximum IOP as the strongest ophthalmic factors, while higher lymphocyte ratio and higher platelet count as the strongest systemic factors associated with faster RNFL thinning. Machine learning-based modeling identified several systemic factors as well as previously acknowledged ophthalmic risk factors associated with long-term rapid RNFL thinning.

Recent Development of Radiofluorination of Boron Agents for Boron Neutron Capture Therapy of Tumor: Creation of 18F-Labeled C-F and B-F Linkages.

Boron neutron capture therapy (BNCT) is a binary therapeutic technique employing a boron agent to be delivered to the tumor site followed by the irradiation of neutrons. Biofunctional molecules/nanoparticles labeled with F-18 can provide an initial pharmacokinetic profile of patients to guide the subsequent treatment planning procedure of BNCT. Borono phenylalanine (BPA), recognized by the l-type amino acid transporter, can cross the blood-brain barrier and be accumulated in gliomas. The radiofluoro BNCT agents are reviewed by considering (1) less cytotoxicity, (2) diagnosing and therapeutic purposes, (3) aqueous solubility and extraction route, as well as (4), the trifluoroborate effect. A trifluoroborate-containing amino acid such as fluoroboronotyrosine (FBY) represents an example with both functionalities of imaging and therapeutics. Comparing with the insignificant cytotoxicity of clinical BPA with IC50 > 500 μM, FBY also shows minute toxicity with IC50 > 500 μM. [18F]FBY is a potential diagnostic agent for its tumor to normal accumulation (T/N) ratio, which ranges from 2.3 to 24.5 from positron emission tomography, whereas the T/N ratio of FBPA is greater than 2.5. Additionally, in serving as a BNCT therapeutic agent, the boron concentration of FBY accumulated in gliomas remains uncertain. The solubility of 3-BPA is better than that of BPA, as evidenced by the cerebral dose of 3.4%ID/g vs. 2.2%ID/g, respectively. While the extraction route of d-BPA differs from that of BPA, an impressive T/N ratio of 6.9 vs. 1.5 is noted. [18F]FBPA, the most common clinical boron agent, facilitates the application of BPA in clinical BNCT. In addition to [18F]FBY, [18F] trifluoroborated nucleoside analog obtained through 1,3-dipolar cycloaddition shows marked tumoral uptake of 1.5%ID/g. Other examples using electrophilic and nucleophilic fluorination on the boron compounds are also reviewed, including diboronopinacolone phenylalanine and nonsteroidal anti-inflammatory agents.

Symmetries and Zero Modes in Sample Path Large Deviations

Sharp large deviation estimates for stochastic differential equations with small noise, based on minimizing the Freidlin–Wentzell action functional under appropriate boundary conditions, can be obtained by integrating certain matrix Riccati differential equations along the large deviation minimizers or instantons, either forward or backward in time. Previous works in this direction often rely on the existence of isolated minimizers with positive definite second variation. By adopting techniques from field theory and explicitly evaluating the large deviation prefactors as functional determinant ratios using Forman’s theorem, we extend the approach to general systems where degenerate submanifolds of minimizers exist. The key technique for this is a boundary-type regularization of the second variation operator. This extension is particularly relevant if the system possesses continuous symmetries that are broken by the instantons. We find that removing the vanishing eigenvalues associated with the zero modes is possible within the Riccati formulation and amounts to modifying the initial or final conditions and evaluation of the Riccati matrices. We apply our results in multiple examples including a dynamical phase transition for the average surface height in short-time large deviations of the one-dimensional Kardar–Parisi–Zhang equation with flat initial profile.

Mechanism of wave-induced flow in reshaping breakwaters

The aim of this work was to investigate the reshaping mechanisms of a reshaping berm breakwater (BB) by assessing the results of a two-dimensional numerical model in OpenFoam. The flow inside and outside the breakwater was numerically simulated. The initial and reshaped form of the breakwater was modelled using the Darcy–Forchheimer equation and k–ϵ closure model. The numerical model was calibrated with and validated against experimental data of wave-induced pressure and water-level fluctuations inside and outside the breakwater. Both the initial and reshaped BB were evaluated for calibration and validation processes. The results show that the minimum run-down level on the breakwater slope is a critical area for armour instability due to outward driving forces caused by the critically synchronised outward flow and excess pressure gradient. Moreover, parallel downward flow occurs during a wave run-down, which can push the displaced armour down the slope. After reshaping, the breakwater profile has a milder slope than the initial profile, and the outward forces due to the excess pressure gradient are reduced to less than one-half of their initial amount, a result of the change in breaker type. Accordingly, the reshaped profile is modified to harmonise with the new flow field conditions.

Crystalline surface diffusion flow for graph-like curves

This paper studies a fourth-order crystalline curvature flow equation for a graph-like curve. The equation is a special example of general crystalline surface diffusion flow. We consider a special class of piecewise linear periodic functions and calculate its speed. We introduce the notion of firmness and prove that the solution stays firm at least for a short time for firm initial data. We show that a facet (flat part) may split if the initial profile is not firm by giving an explicit example. Moreover, we give an example of facet-merging as well as several estimates for the speed of each facet.

Iterative assist-as-needed control with skill learning for physical human-robot interaction

Collaborative robots referring to physical human-robot interaction applications have drawn considerable attention. There have been lots of methods based on skill learning to help robots mimic human collaborative behaviors. However, the stiffness profiles generated by these methods only rely on the quality of collected human demonstrations and cannot be adjusted according to detailed interaction tasks. To this end, this paper combines a skill learning method and an iterative assist-as-needed impedance controller. The skill learning method encodes and generates position and stiffness references. The iterative assist-as-needed controller enables the robot to adjust the generated stiffness profile actively according to the human intention. When the human tries to act as an active role in interaction tasks, the controller takes a lower stiffness parameter, which means it can tolerate more deviation from the desired trajectory, and vice versa. Compared to the previous results, on the one hand, this paper employs a skill learning method to generate an initial stiffness profile for the iterative assist-as-needed controller, which enables the robot to mimic human behaviors; on the other hand, the controller proposed in this paper allows the manual design of the damping and mass parameters while the previous controller accepts only the desired stiffness parameter. Finally, one simulation and one experiment are demonstrated to evaluate the performance of the designed controller.

Morphological Characteristics of Foveal Pit Base and Its Impact on Visual Acuity in Macular Pseudoholes

Introduction: To investigate the characteristics of macular pseudoholes (MPHs) with different foveal profiles and their impact on preoperative and postoperative visual acuity (VA). Methods: A retrospective review of 47 eyes from 46 consecutive patients with MPH who had undergone vitrectomy was conducted. The MPHs were classified into u-shape and v-shape according to the morphological description of the foveola base. The best-corrected visual acuity (BCVA), central foveal point thickness, parafoveal thickness, parafoveal inner and outer retinal thickness, stretched lamellar cleavage, microcystic macular edema (MME), disorganization of retinal inner layers (DRIL), and the integrity of outer retinal layers were recorded. Results: The eyes in the v-shaped group (n = 31) had lower BCVA, thicker retinal thickness, more intraretinal cleavage, MME, and DRIL than the u-shaped (n = 16) group (all p < 0.05). Multiple regression analysis revealed that the morphology of the foveola base was significantly related to the preoperative BCVA (p = 0.025). The VA was significantly improved in both groups, and the improvement was greater in the v-shaped group (p = 0.024). No significant difference was found in the postoperative BCVA between the two groups (all p > 0.05). Conclusion: The v-shape, reflecting the stretch in the foveola, had a significant impact on preoperative BCVA. However, the VA was improved after surgery whatever their initial foveal profile.

Group Cooperation in Intergroup Conflicting Networks: An Evolutionary Game Approach

Most intergroup conflicts arise from rivalry over limited resources, malicious disturbance, or hostile attitudes; therefore, it is critical to investigate individuals’ behaviors involved in intergroup conflicting contexts. Focusing on cooperation issues among individuals, in this study we establish an evolutionary game framework for analyzing cooperation and conflicts that arise within and inter-groups of intergroup conflicting networks. We first model the intergroup conflicting networked evolutionary games (ICNEGs). Then, we analyze the ICNEGs and prove that the evolution of ICNEGs can be expressed as a logical dynamic system. Finally, we apply the obtained results to a simplified Israeli-Palestinian conflict scenario. Our case study demonstrates that only by adopting suitable initial strategy profiles can a certain scale of group cooperation be continuously generated without suffering casualties.