bluuebunny/crossref_metadata_2025 huggingface dataset:
The relationship between mothers' Instagram follower count and the concept of sharenting
Authors: Orhan Kiliç Betül , Kiliç Serhat , Konuksever Dilek , Ulukol Betül
Published: February 2024

Background

The phenomenon of sharenting has led to an increase in children's digital presence on social media platforms, particularly Instagram. This study aimed to examine the relationship between features of mothers' Instagram use and their sharing of photos related to their children.

Methods

The present study was conducted with 130 mothers of children who applied to our university hospital and who had an Instagram account and allowed us to follow them. The mothers completed an online questionnaire that consisted of parents' sociodemographic data and data regarding social media use characteristics. We created a new Instagram account for this study, and we examined the mothers' Instagrams via this account. The number of Instagram followers was analyzed by dividing it into four equal 25% percentiles.

Results

The present study found that mothers with more followers shared more photos about themselves and their children on Instagram per year (p < 0.001). It was confirmed that mothers with more followers were more likely to share their children's photos showing them alone, showing them playing, photos that included identity information, and photos that violated their privacy (p values respectively; p = 0.004, p = 0.001, p = 0.043, p = 0.015).

Conclusions

This study highlights the association between mothers' Instagram follower numbers and the presence of risky posts about their children on social media. The number of Instagram followers might serve as a predictor of sharenting behavior. The study's findings are discussed thoroughly, and recommendations are provided for future research and practice in this area.
Comparative analysis of Argentinian and European populations of Ramularia collo‐cygni on barley
Authors: Erreguerena Ignacio A. , Hoebe Peter N. , Carmona Marcelo A. , Guillín Eduardo , Havis Neil D.
Published: February 2024

Ramularia collo‐cygni (Rcc) is a major barley pathogen that causes yield and grain quality losses worldwide. The main sources of Rcc inoculum are the seed and asexual airborne spores. In Argentina, Rcc is considered to be an emerging threat to barley crops, especially as most varieties are susceptible to Rcc and have a European genetic background. Here, we describe the population genetic diversity and structure of the Argentinian Rcc population, based on 10 simple‐sequence repeat (SSR) markers, in order to compare it with Rcc populations from the Czech Republic and Scotland. The Argentinian Rcc population showed lower genetic diversity, higher level of structuring and higher number of clonal isolates than European populations. Significant differentiation at population origin (country) and region (Europe and South America) level suggests the occurrence of a genetic bottleneck and/or a founder effect on Rcc entry to Argentina and that this population could still be in a state of establishment and emergence. Further research on Rcc genetic structure at local and global scale will be crucial for the understanding of Rcc population dynamics for disease management.
Parafoveal and foveal N400 effects in natural reading: A timeline of semantic processing from fixation‐related potentials
Authors: Li Nan , Wang Suiping , Kornrumpf Florian , Sommer Werner , Dimigen Olaf
Published: February 2024

The depth at which parafoveal words are processed during reading is an ongoing topic of debate. Recent studies using RSVP‐with‐flanker paradigms have shown that implausible words within sentences elicit an N400 component while they are still in parafoveal vision, suggesting that the semantics of parafoveal words can be accessed to rapidly update the sentence representation. To study this effect in natural reading, we combined the coregistration of eye movements and EEG with the deconvolution modeling of fixation‐related potentials (FRPs) to test whether semantic plausibility is processed parafoveally during Chinese sentence reading. For one target word per sentence, both its parafoveal and foveal plausibility were orthogonally manipulated using the boundary paradigm. Consistent with previous eye movement studies, we observed a delayed effect of parafoveal plausibility on fixation durations that only emerged on the foveal word. Crucially, in FRPs aligned to the pretarget fixation, a clear N400 effect emerged already based on parafoveal plausibility, with more negative voltages for implausible previews. Once participants fixated the target, we again observed an N400 effect of foveal plausibility. Interestingly, this foveal N400 was absent whenever the preview had been implausible, indicating that when a word's (im)plausibility is already processed in parafoveal vision, this information is not revised anymore upon direct fixation. Implausible words also elicited a late positive component (LPC), but exclusively when in foveal vision. Our results not only provide convergent neural and behavioral evidence for the parafoveal uptake of semantic information, but also indicate different contributions of parafoveal versus foveal information toward higher level sentence processing.
Long term (1901−2021) trends and prediction of climatic variability in selected agro‐ecological zones of Himachal Pradesh using coupled statistical and machine learning approaches
Authors: Thakur Swati , Kumar Manish , Tiwari Akash , Yadav Ankur , Soni Tamanna , Tripathi Dinesh Kumar
Published: February 2024

This study analyses the trends of changing climatic elements in the hydrological regime of the Indian Himalayan Region with specific focus on Agro‐ecological zone II & III of Himachal Pradesh for the period of 1901−2021. The upper, middle, and lower catchment areas of Sutlej River Basin were studied to reveal regional trends in climatic parameters. The Mann‐Kendall test and Sen Slope analysis were used to estimate annual and seasonal trends and their magnitude. The results showed a significant decreasing trend in the lower catchment area, with a break point year estimated to be 1953 for the entire basin. Two blocks of analysis, 1901−1953 and 1954−2021, showed significant variations. Annual rainfall data revealed a statistically significant decreasing trend at different stations. The lower catchment area received a significant increase in rainfall compared to higher altitude stations. In terms of seasonal variation, the pre‐monsoon season showed a significant decrease, while the entire basin recorded a significant increase in average monthly temperature. The study concludes by generating future time series predictions using an ANN model for the period of 2022−2050. Overall, the study's findings indicate a significant change in climatic variables with signs of increasing monthly temperatures and decreasing annual rainfall.
Skin patch based makeup finish assessment technique by deep neural network
Authors: Nishino Ken
Published: February 2024

Background

Skin color and texture play a significant role in influencing impressions. To understand the influence of skin appearance and to develop better makeup products, objective evaluation methods for makeup finish have been explored. This study aims to apply machine learning technology, specifically deep neural network (DNN), to accurately analyze and evaluate delicate and complex cosmetic skin textures.

Methods

“Skin patch datasets” were extracted from facial images and used to train a DNN model. The advantages of using skin patches include retaining fine texture, eliminating false correlations from non‐skin features, and enabling visualization of the inferred results for the entire face. The DNN was trained in two ways: a classification task to classify skin attributes and a regression task to predict the visual assessment of experts. The trained DNNs were applied for the evaluation of actual makeup conditions.

Results

In the classification task training, skin patch‐based classifiers for age range, presence or absence of base makeup, formulation type (powder/liquid) of the applied base makeup, and immediate/while after makeup application were developed. The trained DNNs on regression task showed high prediction accuracy for the experts’ visual assessment. Application of DNN to the evaluation of actual makeup conditions clearly showed appropriate evaluation results in line with the appearance of the makeup finish.

Conclusion

The proposed method of using DNNs trained on skin patches effectively evaluates makeup finish. This approach has potential applications in visual science research and cosmetics development. Further studies can explore the analysis of different skin conditions and the development of personalized cosmetics.
Lipolytic agents for submental fat reduction: Review
Authors: Park Soo Yeon , Kim Soo‐Bin , Wan Jovian , Felice Fernando , Yi Kyu‐Ho
Published: February 2024

Result

The review delves into the realm of reducing submental fat, presenting a comprehensive analysis of various lipolytic agents used in plastic surgery and dermatology. The introduction establishes the context by defining the key indicators of a youthful neck and emphasizing the significant influence of fat in the aging process, particularly in the submental area. The usage of aminophylline involves subcutaneous injections, facilitating fat breakdown by increasing cyclic adenosine monophosphate and inhibiting adenosine receptors. Hypotonic pharmacologic lipo‐dissolution induces fat dissolution via injected compounds under pressure, while lipolytic lymphatic drainage employs hyaluronidase to reduce tissue viscosity, aiding fat circulation. Glycerophosphorylcholine containing choline alfoscerate claims to activate fat metabolism, whereas the utilization of phosphatidylcholine combined with deoxycholate lacks cosmetic approval due to safety concerns. Deoxycholic acid has FDA approval for submental fat reduction, yet its mechanisms remain incompletely understood. Understanding the complex anatomy and mechanisms of lipolytic agents is essential for safe and effective submental fat reduction, despite evolving practices and off‐label utilization. Clinical guidelines and references support this discussion, offering insights for safer applications.
Overcoming life stage‐centric biases illuminates arthropod diversity, systematics and biology
Authors: Caterino Michael S. , Recuero Ernesto
Published: February 2024

Synthetic studies of arthropod systematics and biodiversity are hindered by overreliance on ‘preferred’ semaphoronts, those life stages (typically adult males) that provide the most taxonomically distinctive characters. However, modern sequence‐based methods for inventory have no such limitations and permit incorporation of any and all representatives of a species. Here, we briefly review the growth and potential of these approaches to faunistic and systematic studies and share results from our own recent work that illustrate the value that other morphs, immature stages and females added to these studies.
Gröbner bases, symmetric matrices, and type C Kazhdan–Lusztig varieties
Authors: Escobar Laura , Fink Alex , Rajchgot Jenna , Woo Alexander
Published: February 2024

We study a class of combinatorially defined polynomial ideals that are generated by minors of a generic symmetric matrix. Included within this class are the symmetric determinantal ideals, the symmetric ladder determinantal ideals, and the symmetric Schubert determinantal ideals of A. Fink, J. Rajchgot, and S. Sullivant. Each ideal in our class is a type C analog of a Kazhdan–Lusztig ideal of A. Woo and A. Yong; that is, it is the scheme‐theoretic defining ideal of the intersection of a type C Schubert variety with a type C opposite Schubert cell, appropriately coordinatized. The Kazhdan–Lusztig ideals that arise are exactly those where the opposite cell is 123‐avoiding. Our main results include Gröbner bases for these ideals, prime decompositions of their initial ideals (which are Stanley–Reisner ideals of subword complexes), and combinatorial formulas for their multigraded Hilbert series in terms of pipe dreams.
Simulation of the Childbirth Process in ls-dyna
Authors: Tao Ru , Grimm Michele J
Published: February 2024

Childbirth or labor, as the final phase of a pregnancy, is a biomechanical process that delivers the fetus from the uterus. It mainly involves two important biological structures in the mother, the uterus—generating the pushing force on the fetus—and the pelvis (bony pelvis and pelvic floor muscles)—resisting the movement of the fetus. The existing computational models developed in this field that simulate the childbirth process have focused on either the uterine expulsion force or the resistive structures of the pelvis, not both. An FEM model including both structures as a system was developed in this paper to simulate the fetus delivery process in ls-dyna. Uterine active contraction was driven by contractile fiber elements using the Hill material model. The passive portion of the uterus and pelvic floor muscles were modeled with Neo Hookean and Mooney–Rivlin materials, respectively. The bony pelvis was modeled as a rigid body. The fetus was divided into three components: the head, neck, and body. Three uterine active contraction cycles were modeled. The model system was validated based on multiple outputs from the model, including the stress distribution within the uterus, the maximum Von Mises and principal stress on the pelvic floor muscles, the duration of the second stage of the labor, and the movement of the fetus. The developed model system can be applied to investigate the effects of pathomechanics related to labor, such as pelvic floor disorders and brachial plexus injury.
Design Method for Impeller of Centrifugal Pump With Guide Vanes Based on Oseen Vortex
Authors: Lu Yangping , Liu Ming , Tan Lei , Liu Demin
Published: February 2024

Centrifugal pumps with guide vanes (GVs) are widely used in a pump as turbine, energy storage pump station, and water diversion project. The objective of this study is to establish a design method of centrifugal pumps for matching impeller outlet and diffuser inlet to reduce hydraulic loss. To this end, a theoretical prediction model based on the fluid governing equation and the Oseen vortex model is proposed to predict the velocity moment downstream the impeller of the centrifugal pump. Then, a design method is established to design the impeller of the centrifugal pump with guide vanes. A centrifugal pump with a specific speed of 127 is used to validate the theoretical prediction model, and results of velocity moment show that the deviation between predicted and simulated results is below 0.5% in average. Finally, the design method is applied, and results show that the average efficiency of redesigned pump under the working conditions is 1.04% higher than that of baseline pump, which validates the reliability of proposed design method by theoretical prediction based on Oseen vortex. Analysis on velocity distribution and turbulence eddy dissipation shows that the design method based on Oseen vortex can effectively improve the flow pattern and pump performance.
Mapping Novice Designer Behavior to Design Fixation in the Early-Stage Design Process
Authors: Jia Miao , Jiang Shuo , Qi Jin , Hu Jie
Published: February 2024

In the engineering design process, design fixation significantly constrains the diversity of design solutions. Numerous studies have aimed to mitigate design fixation, yet determining its occurrence in real-time remains a challenge. This research seeks to systematically identify the emergence of fixation through the behavior of novice designers in the early stages of the design process. We conducted a laboratory study, involving 50 novice designers possessing engineering drafting skills. Their design processes were monitored via video cameras, with both their design solutions and physical behaviors recorded. Subsequently, expert evaluators categorized design solutions into three types: Fixation, Low-quality, and Innovative. We manually recorded the names and durations of 31 different physical behaviors observed in the videos, which were then coded and filtered. Meanwhile, we propose a filtering and calculation method for the behavior in the design process. From this, four fixation behaviors were identified using variance analysis (ANOVA): Touch Mouth (TM), Touch Head (TH), Rest Head in Hands (RH), and Hold Face in Hands (HF). Our findings suggest that continuous interaction between the hand and head, mouth, or face can be indicative of a fixation state. Finally, we developed a Behavior-Fixation model based on the Support Vector Machine (SVM) for stage fixation judgment tasks, achieving an accuracy rate of 85.6%. This machine-learning model outperforms manual assessment in speed and accuracy. Overall, our study offers promising prospects for assisting designers in recognizing and avoiding design fixation. These findings, coupled with our proposed computational techniques, provide valuable insights for the development of automated and intelligent design innovation systems.
Simulations Predicting the Effects of Detonation Velocity on the Speed and Temperature of Shaped Charge Jets
Authors: Doney Robert
Published: February 2024

In this report, I evaluate the effects of a warhead's detonation velocity on the resulting speed and thermodynamic state of shaped charge jets using the multiphysics code, ALEGRA. Specifically, I investigate a 65-mm, bare, shaped charge jet, generated from explosives that feature detonation velocities ranging from 6.84 to 9.11 km/s with a fixed geometry. Data showed a general trend for all cases: a hot axis that cools off with increasing radius according to a second-order polynomial. At higher detonation velocities, the jet axis is predicted to be liquid. This is coincident with copper material that is faster along the axis and leads the jet tip, forming a proboscis. At slower deteonation velocities this phenomena vanishes and the jet appears to be a solid.
Detection of Radio Frequency Waves in Hypervelocity Impact and its Energy Dependence with Mass and Velocity of the Impactor
Authors: Fereydooni Kimia , Lee Nicolas , Close Sigrid
Published: February 2024

Satellites we launch into space are subject to hazards caused by space weather, incorrect orbit, internal problems and most importantly, collisions. These collisions are a result of orbital debris and meteoroids impacting the satellites and can cause mechanical and electrical anomalies. While most of the mechanical damage is well studied and is easy to diagnose, more than half of the electrical anomalies are still unknown and may be attributed to hypervelocity impact (HVI). HVI refers to a collision where the projectile speed exceeds the speed of sound in the tar-get material and its impact energy ionizes the material near the surface, generates plasma, emits light flash and depending on the impact conditions produces radio frequency (RF) emissions. It is crucial to study RF emission as it can be intercepted by the spacecraft electronics and cause electromagnetic interference (EMI), which can result in damage to vulnerable electronic components of the spacecraft.
Study on Hypervelocity Impact of SRM Slag with Voids
Authors: Fujii Masanori , Nitta Kumi , Higashide Masumi , Akahoshi Yasuhiro , Koura Takao
Published: February 2024

Solid rocket motors are mainly used for launching small satellites because they have a small number of parts, simple structures, and high responsiveness. However, there are concerns about solid rocket motors, which release solid rocket motor slag (SRM slag). The SRM slag is derived from aluminum powder in a solid matrix and released as agglomerated alumina into outer space before and after the solid rocket motor is cutoff. It has been confirmed that voids inside themselves in combustion tests in a vacuum conducted by JAXA. In this paper focusing on SRM slag with voids, we simulated its impact with diameters ranging from 1 mm to 10 mm, with porosities ranging from 0 % to 80 %, and with impact velocities of 2-15 km/s towards enough thick targets. We investigated the potential danger of SRM slag with voids using AUTODYN-2D. In addition, we calculated the ballistic limit curve (BLC) for each porosity of SRM slag based on the penetration depths obtained by the numerical simulations and compared BLCs in SRM slag and space debris made of aluminum alloy.
Case Study of Meteoroid Fluence on a Mars Sample Return Mission
Authors: Jenkin Alan B , Peterson Glenn E. , Steward Katie , Needels Jacob T. , Gage Peter J. , Gee Ken , Coates Ashley M. , White Todd R. , Squire Michael D.
Published: February 2024

This paper presents results from an analysis to assess the fluence of meteoroids on the Mars Sample Return Campaign Micrometeoroid Protection System (MMPS) and probability of damage to the Earth Entry System Thermal Protection System (TPS). Results are presented for the mission Outbound trajectory from Earth to Mars. The MEM3 meteoroid environment model was used for the assessment. Results are presented showing the reduction in fluence on cube faces and on the MMPS that can be achieved by selection of an anti-velocity orientation of the MMPS. A methodology is presented that determines the cumulative fluence on the MMPS using the MEM3 meteoroid fluxes and the spacecraft attitude profile over the trajectory. Resulting distributions of fluence over impact velocity, angle, and mass are presented. The fluence results are used to establish velocity-angle scenarios for hydrocode simulation and to assess net damage fluence to the TPS. Example tables containing Smooth Particle Hydrodynamics Code (SPHC) simulation scenarios as well as hypothetical hydrocode simulation scenarios for illustration purposes are presented. The tables present the resulting net damaging fluence to the TPS for each scenario and the total across the scenarios. Additionally, examples of CTH hydrocode simulation are included, demonstrating their use for determining critical impactor across the impactor parameter space, and damage of impactors that penetrate the MMPS.
Failure of Fuel Tanks Due to High Velocity Projectiles Impact
Authors: Ji Yangziyi , Li Xiangdong , Zhou Lanwei , Chen Junliang
Published: February 2024

The impact of high-velocity projectiles on fluid-filled containers is a matter of interest in the study of vehicle and aircraft vulnerability. In this paper, tests of high-velocity projectiles impacting typical truck-integrated fuel tanks were conducted. It is found that during a certain range of projectile impact energy before the fuel tank wall begins to crack, the deformation of the fuel tank wall does not increase with the increase of the projectile impact energy, while maintaining a certain value. Besides, this value is the same for both entry and exit walls. Preliminary finite element analysis shows that the HRAM loading during the cavity oscillation phase contributes to the deformation of the exit wall most.
Quantitative Analysis of Physical Properties of Shaped Charge Jet by the use of IN-SITU Mass Analysis From X-RAY Image Processing (I-MAX)
Authors: Saito Fumikazu , Kishimura Hiroaki , Takizawa Yutaka , Okada Yohsuke , Ogino Takashi , Nakashita31 Mitsuyori
Published: February 2024

Al-shaped-charge-jet (Al SCJ) generated from conical liner under explosive shock loading is observed using a hard flash xray and x-ray imaging plate. An analytical method termed insitu mass analysis from x-ray image processing (i-MAX) was utilized to estimate the mass, velocity, and kinetic energy of the SCJ in this study. The mass distributions in the SCJ showed the tendency to decrease toward the jet's tip, except in the vicinity of the jet's tip. Kinetic energy showed the maximum value (2080±582 J) at the jet's tip. The collision/penetration experiment against an iron target block was conducted to evaluate the penetration ability of the Al SCJ. The Al SCJ impact against the Fe target observed no bulk aluminum or slag on the penetration hole. These results suggest that the shape (depth and width) and condition (residuals in the hole) of the penetration holes also strongly depend on the metallic characteristics of the liner and the physical properties of the SCJ. These results suggest that the shape and condition of the penetration holes strongly depend on the liner's metallic characteristics (melting point) and the physical property (kinetic energy) of the SCJ.
Transition Regime between High-Velocity and Hypervelocity Impact and Related Energy Partitioning in Metals: State-of-the-Art Review, Characterization, and Modeling
Authors: Signetti Stefano , Heine Andreas
Published: February 2024

We discuss how established modeling approaches for metals in terminal ballistics can be extended towards higher impact velocities, yet below the threshold of purely hydrodynamic behavior. While at the upper bound of the high-velocity penetration regime the effects of material strength and failure are dominating, the ideal hydrodynamic behavior is still not achieved until velocities of several kilometers per second. The transition regime in between sees a gradual shift from effects dominated by strength to those connected with the increase of internal energy, such as thermal softening and melting. Therefore, the coexistence of different multi-physics phenomena makes this intermediate domain of paramount interest, especially for computational scientists. A physics-based characterization of the transition regime is discussed alongside penetration data, partition measurements, and experimental observation from different literature sources. The key results of an extensive literature review with a focus on the relevant phenomena for impact modeling of metals up to hypervelocity conditions are presented. Limits and prospects of hydrocode simulation for energy partitioning computation as well as relatively novel approaches for the field of impact research are discussed. This conference paper summarizes the recent research on the topic conducted in our group. Related results and discussions are taken from earlier publications by the authors on which the text of this contribution is based.
Experimental Investigation of Impact Flash Emission and Ejection Phenomena in Hypervelocity Impacts on Metals
Authors: Simpson Gary , Shaeffer Matt , Moreno Justin , Ramesh KT
Published: February 2024

A common feature of many high-velocity and hypervelocity projectile impacts is an intense burst of optical emission commonly called an impact flash. The impact flash can easily obscure observation of the earliest moments of projectile contact and penetration, making it somewhat detrimental to the experimentalist. However, the impact flash contains signatures of the earliest, most energetic processes at work during this critical phase and potentially offers valuable information for applications such as remote impact damage assessment. A multitude of mechanisms and interactions can contribute to the impact flash; a thorough understanding of the structure and nature of the flash generation itself under the experimental conditions of relevance is necessary to properly interpret any flash emission measurement. This work attempts to investigate the nature of impact flash emission for spherical impacts on metals under experimental conditions common to impact research experiments at the HyFIRE facility at Johns Hopkins. Time-resolved emission spectroscopy, photometry, and ultrahigh- speed multispectral imaging are used to identify the emission characteristics and structure of the radiating material. Under these conditions, the impact flash is observed to originate almost entirely from the rapid atmospheric ablation of jetted ejecta and debris.
Study of the Effects of Projectile Strength and Density in the Asteroid Deflection by Hypervelocity Impact
Authors: Wakatsuki Yusuke , Koura Takao , Akahoshi Yasuhiro
Published: February 2024

Potentially dangerous asteroids (PHAs) are asteroids that have orbits approaching the Earth and are a threat to humankind. Among them, Apophis and Bennu have been attracting attention in recent years. It is necessary to prevent PHAs from impacting the Earth, so this study focuses on asteroid deflection by hypervelocity impact as an impact avoidance. In this method, a projectile such as a spacecraft is impacted into a PHA at hypervelocity and its orbit will be changed. This method is considered to be the best method because it can achieve asteroid deflection instantaneously and it will cause less secondary disasters by asteroid split.
Crater Ejecta Fragments Size and Shape From Hypervelocity Impacts into AL 2024-T351 Aluminum From 4 to 6 KM/S
Authors: Walker James D. , Chocron Sidney , Grosch Donald J. , Heim F. Michael
Published: February 2024

Utilizing a large two-stage light gas gun, 3-cm-diameter spheres were impacted into Al 2024-T351 targets. The fragments were collected from the floor of the impact chamber and were analyzed. In particular, there is interest as to the fragment size distribution and the fragment shape distribution. The fragments were sorted in size, and those from roughly 0.1 g to 35 g were individually tabulated. This allowed the development of a fragment size distribution for these fragments. Then, all the fragments were optically analyzed to provide a quantitative characterization of their shape. The fragments are predominately flat, a shape that appears to correlate with an intersecting shear plane mechanism for the fragment formation in the crater formation. The fragment distribution shows that there are two different fragment formation mechanisms, which it is concluded are due to fragments formed in the interior of the crater entirely of interacting shear planes vs. those whose formation is influenced by the target free surface. The results are compared to other work on fragmentation.
Analysis of Hypervelocity-Impacted thin Films for Space Applications
Authors: Ward Melissa A. , Anz-Meador Phillip D. , Cowardin Heather M.
Published: February 2024

Exposure to the harsh space environment and hypervelocity impacts from micrometeoroids and small orbital debris can affect space operations through long-term degradation of spacecraft materials, surfaces, or systems. Multi-layer insulation (MLI) and coated, polyimide films are spacecraft materials commonly found on the external surfaces of spacecraft for thermal control and protection. Characterizing the damage to these exposed materials with in situ and laboratory measurements can better inform spacecraft designers and operators in understanding and mitigating surface or system degradation. In this paper, we examine flown Hubble Space Telescope (HST) Equipment Bay 5 MLI and coated, polyimide ground test articles to characterize hypervelocity impact damage. Impact feature cavities are inspected to identify damage, which can validate long-term degradation models, improve thermal management systems, or improve accuracy of damage predictions. An overview of the impact characterization using optical microscopy, narrowband spectroscopy, and Scanning Election Microscopy/Energy Dispersive X- ray (SEM/EDX) of the two materials is presented. Observations of robustness in the space environment, as well as a detailed assessment of cratering and penetration statistics for the space-exposed sample, also are discussed.
Prediction and Enhancement of Thermal Protection Systems from Meteoroid Damage using a Smooth Particle Hydrodynamic Code
Authors: Williamsen Joel , Stellingwerf Robert , Evans Steve , Squire Michael
Published: February 2024

Interplanetary spacecraft are exposed to meteoroid fluxes that range in speeds from 10 to 72 km/sec, far above the capability of today’s test facilities to provide predictions for the likelihood of spacecraft critical penetration. Of special interest are sample return missions, which (though protected by shielding) must often survive years of exposure to the meteoroid environment in order to re-enter Earth’s atmosphere with their scientific cargo.

This paper describes the simulation of meteoric material damage to thermal protection systems (TPS) housed beneath protective “garage” (shielding) enclosures using the Smooth Particle Hydrodynamics Code (SPHC) operated by the Institute for Defense Analyses and Stellingwerf Consulting in support of ongoing NASA tasks. The study outlined in this paper considered the impact effect of both meteoric materials such as iron, ice, and chondrites (dunnite), and non-meteoric materials such as aluminum and nylon against both external shielding materials (single and dual aluminum bumpers) and Heat shield for Extreme Entry Environments Technology (HEEET) TPS materials, used alone and in conjunction with shielding. A general predictive damage equation to HEEET TPS is developed from these SPHC simulations for velocities up to 70 km/sec.
Experiments on the Survivability of Extremophiles
Authors: Zhao Lily , Perez-Fernandez Cesar A. , DiRuggiero Jocelyne , Ramesh K. T.
Published: February 2024

The ability of terrestrial microorganisms to survive extreme conditions is an important consideration for developing and determining mission criteria, especially for future sample return missions. Of the numerous extreme conditions in space, the effect of impact is an important one for planetary protection. Impacts are complex phenomena with conditions that vary widely but typically involve high stresses sustained for short times. We aim to adapt the pressure-shear plate impact experiment to investigate how impact stresses affect the survival of microorganisms (in particular, extremophiles). Experiments are underway on Deinococcus radiodurans to validate the experimental design and establish testing protocols for such extremophiles.
Updates on the Debrisat Hypervelocity Experiment and Characterization of Fragments in Support of Environmental Models
Authors: Cowardin Heather , Cruz Corbin , Murray James , Seago John , Manis Alyssa , Gates Drake , Reyes Jackie , Opiela John
Published: February 2024

To develop, maintain, and update orbital debris environmental and break-up models, such as the NASA orbital debris engineering model (ordem) and the NASA standard satellite breakup model (ssbm), the NASA orbital debris program office (odpo) relies on the most recent validated datasets from various measurement sources, both laboratory and environmental. One key project that will provide insight for break-up events using modern-day spacecraft mate-rials and construction techniques is the debrisat laboratory hypervelocity-impact test. Based on the mass of the target, the projectile, and the impact velocity, the expected number of fragments greater than 2 mm, generated using the NASA ssbm, was estimated to be close to 85,000. To date, the debrisat fragment database continues to grow, with over 200,000 fragments collected that will help inform updates to the ssbm. Additionally, the growing fragment ensemble will support key parameters for the next release of NASA’s environmental models, employing fragment shapes, densities, and size distributions.
Observation of structural defects in GaN/InGaN multi-quantum wells grown on semipolar (112¯2) substrate using cathodoluminescence in transmission electron microscopy
Authors: Sheen Mi-Hyang , Lee Yong-Hee , Nam Okhyun , Kim Young-Woon
Published: February 2024

Defect structures of semipolar GaN thin film, grown on the m-plane of sapphire, were investigated using the home-built cathodoluminescence (CL) stage in TEM. The CL maps with high spatial resolution identify the type of basal plane stacking faults (BSFs) and visualize their distribution. I1-BSF type defects had the highest population and the I2-BSF type defect was revealed in the form of thin strips with less population. Partial dislocations and basal stacking fault-related defects existed in the form of segmented lines but with strong luminescence characteristics. TEM-CL was able to identify the distribution and the characteristic luminescence from the defects, which were difficult to discern in the typical defect analysis.
Impact of high-power impulse magnetron sputtering pulse width on the nucleation, crystallization, microstructure, and ferroelectric properties of hafnium oxide thin films
Authors: Jaszewski Samantha T. , Fields Shelby S. , Chung Ching-Chang , Jones Jacob L. , Orson Keithen G. , Reinke Petra , Ihlefeld Jon F.
Published: February 2024

The impact of the high-power impulse magnetron sputtering (HiPIMS) pulse width on the crystallization, microstructure, and ferroelectric properties of undoped HfO2 films is investigated. HfO2 films were sputtered from a hafnium metal target in an Ar/O2 atmosphere, varying the instantaneous power density by changing the HiPIMS pulse width with fixed time-averaged power and pulse frequency. The pulse width is shown to affect the ion-to-neutral ratio in the depositing species with the shortest pulse durations leading to the highest ion fraction. In situ x-ray diffraction measurements during crystallization demonstrate that the HiPIMS pulse width impacts nucleation and phase formation, with an intermediate pulse width of 110 μs stabilizing the ferroelectric phase over the widest temperature range. Although the pulse width impacts the grain size with the lowest pulse width resulting in the largest grain size, the grain size does not strongly correlate with the phase content or ferroelectric behavior in these films. These results suggest that precise control over the energetics of the depositing species may be beneficial for forming the ferroelectric phase in this material.
Characteristics of truncation resonances in periodic bilayer rods and beams with symmetric and asymmetric unit cells
Authors: Park Sangwon , Yan Ryan F. , Matlack Kathryn H.
Published: February 2024

Truncation resonances are resonant frequencies that occur within bandgaps and are a prominent feature of finite phononic crystals. While recent studies have shed light on the existence conditions and modal characteristics of truncation resonances in discrete systems, much remains to be understood about their behavior in continuous structures. To address this knowledge gap, this paper investigates the existence and modal characteristics of truncation resonances in periodic bilayer beams, both numerically and experimentally. Specifically, the effect of symmetry of the unit cells, boundary conditions, material/geometric properties, and the number of unit cells are studied. To this end, we introduce impedance and phase velocity ratios based on the material and geometric properties and show how they affect the existence of truncation resonances, relative location of the truncation resonances within the bandgap, and spatial attenuation or degree of localization of the truncation resonance mode shapes. Finally, the existence and mode shapes of truncation resonances are experimentally validated for both longitudinal and flexural cases using three-dimensional (3D) printed periodic beams. This paper highlights the potential impact of these results on the design of finite phononic crystals for various applications, including energy harvesting and passive flow control.
So many toadfish, so little time
Authors: Mensinger Allen F.
Published: February 2024

The oyster toadfish, Opsanus tau, has been a valuable biomedical model for a wide diversity of studies. However, its vocalization ability arguably has attracted the most attention, with numerous studies focusing on its ecology, behavior, and neurophysiology in regard to its sound production and reception. This paper reviews 30 years of research in my laboratory using this model to understand how aquatic animals detect, integrate, and respond to external environment cues. The dual vestibular and auditory role of the utricle is examined, and its ability to integrate multimodal input is discussed. Several suggestions for future research are provided, including in situ auditory recording, interjecting natural relevant ambient soundscapes into laboratory sound studies, adding transparency to the field of acoustic deterrents, and calls for fish bioacoustics teaching modules to be incorporated in K-12 curricula to excite and diversify the next generation of scientists.
Validity and Reliability of Finger-Strength Testing in 6 Common Grip Techniques for the Assessment of Bouldering Ability in Men
Authors: Söderqvist Karl , Identeg Fredrik , Zimmerman Jonas , Senorski Eric Hamrin , Sansone Mikael , Hedelin Henrik
Published: February 2024

Objective: To determine the criterion validity and test–retest reliability of isometric finger-strength testing in 6 differentiated grip techniques for the assessment of bouldering ability among male climbers. Methods: We recruited participants at climbing gyms in Sweden and through online advertisements. We included climbers over 15 years of age with a minimum bouldering performance level of 17 International Rock Climbing and Research Association (IRCRA) for men and 15 IRCRA for women. We tested unilateral, maximal isometric peak finger strength in the front 3 drag, half crimp, closed crimp, 35 sloper, 45 × 90-mm, and 90 × 90-mm pinch through maximal force deloaded of a force plate. We analyzed criterion validity, test–retest reliability, and capacity to determine bouldering performance ability using a stepwise multivariable regression model. Results: Women were excluded from the analysis due to insufficient sample size (n = 16). Thirty-two male participants were included in the primary analysis. The median (interquartile range) age in the advanced and elite group was 27 (25; 35) and 23 (22; 32) years, respectively. The half crimp for the participants’ weak and strong hand displayed the highest ability to determine bouldering grade performance, explaining 48% to 58% of the variance. In the stepwise regression, maximal strength in the half crimp and the front 3 drag collectively explained 66% of the variance for performance. Conclusion: Strength in the half crimp proved the most important performance indicator. The results of this study provide a reliable and valid framework for maximal isometric peak finger-strength testing in advanced and elite male boulderers.
Type III-B CRISPR-Cas cascade of proteolytic cleavages
Authors: Steens Jurre A. , Bravo Jack P. K. , Salazar Carl Raymund P. , Yildiz Caglar , Amieiro Afonso M. , Köstlbacher Stephan , Prinsen Stijn H. P. , Andres Ane S. , Patinios Constantinos , Bardis Andreas , Barendregt Arjan , Scheltema Richard A. , Ettema Thijs J. G. , van der Oost John , Taylor David W. , Staals Raymond H. J.
Published: February 2024

The generation of cyclic oligoadenylates and subsequent allosteric activation of proteins that carry sensory domains is a distinctive feature of type III CRISPR-Cas systems. In this work, we characterize a set of associated genes of a type III-B system from
Haliangium ochraceum
that contains two caspase-like proteases, SAVED-CHAT and PCaspase (prokaryotic caspase), co-opted from a cyclic oligonucleotide–based antiphage signaling system (CBASS). Cyclic tri–adenosine monophosphate (AMP)–induced oligomerization of SAVED-CHAT activates proteolytic activity of the CHAT domains, which specifically cleave and activate PCaspase. Subsequently, activated PCaspase cleaves a multitude of proteins, which results in a strong interference phenotype in vivo in
Escherichia coli.
Taken together, our findings reveal how a CRISPR-Cas–based detection of a target RNA triggers a cascade of caspase-associated proteolytic activities.
Arterial pulses link heart-brain oscillations
Authors: Hamill Owen P.
Published: February 2024

A central baroreceptor monitors arterial pressure to modulate brain activity
SMU_1361c regulates the oxidative stress response of
Streptococcus mutans
Authors: Yu Shuxing , Ma Qizhao , Huang Jun , Liu Yaqi , Li Jing , Wang Yan , Gong Tao , Zhang Qiong , Zou Jing , Li Yuqing
Published: February 2024

Dental caries is the most common chronic infectious disease around the world and disproportionately affects the marginalized socioeconomic group.
Streptococcus mutans
, considered a primary etiological agent of caries, depends on the coordinated physiological response to tolerate the oxidative stress generated by commensal species within dental plaque, which is a critical aspect of its pathogenicity. Here, we identified and characterized a novel tetracycline repressor family regulator, SMU_1361c, which appears to be acquired by the bacteria via horizontal gene transfer. Surprisingly,
smu_1361c
functions as a negative transcriptional regulator to regulate gene expression outside its operon and is involved in the oxidative stress response of
S. mutans
. The
smu_1361c
overexpression strain UA159/pDL278-
1361c
was more susceptible to oxidative stress and less competitive against hydrogen peroxide generated by commensal species
Streptococcus gordonii
and
Streptococcus sanguinis
. Transcriptomics analysis revealed that
smu_1361c
overexpression resulted in the significant downregulation of 22 genes, mainly belonging to three gene clusters responsible for the oxidative stress response. The conversed DNA binding motif of SMU_1361c was determined by electrophoretic mobility shift and DNase I footprinting assay with purified SMU_1361c protein; therefore,
smu_1361c
is directly involved in gene transcription related to the oxidative stress response. Crucially, our finding provides a new understanding of how
S. mutans
deals with the oxidative stress that is required for pathogenesis and will facilitate the development of new and improved therapeutic approaches for dental caries.

IMPORTANCE

Streptococcus mutans
is the major organism associated with the development of dental caries, which globally is the most common chronic disease. To persist and survive in biofilms,
S. mutans
must compete with commensal species that occupy the same ecological niche. Here, we uncover a novel molecular mechanism of how tetracycline repressor family regulator
smu_1361c
is involved in the oxidative stress response through transcriptomics analysis, electrophoretic mobility shift assay, and DNase I footprinting assay. Furthermore, we demonstrated that
smu_1361c
mediates
S. mutans
sensitivity to oxidative stress and competitiveness with commensal streptococci. Therefore, this study has revealed a previously unknown regulation between
smu_1361c
and genes outside its operon and demonstrated the importance of
smu
_
1361c
in the oxidative stress response and the fitness of
S. mutans
within the plaque biofilms, which can be exploited as a new therapy to modulate ecological homeostasis and prevent dental caries.