Lateral Processes Research Articles

Preoperative Talocalcaneal Distance and Subtalar Fusion are Not Associated with Worse Patient-Reported Outcomes in Progressive Collapsing Foot Deformity

Category: Hindfoot; Other Introduction/Purpose: As progressive collapsing foot deformity (PCFD) advances, narrowing between the lateral talar process and calcaneus at the angle of Gissane often occurs. This signifies more advanced peri-talar subluxation and may result in sinus tarsi impingement. However, the clinical significance of narrowing at the angle of Gissane and its effect on patient-reported outcomes following a flatfoot reconstruction is unknown. The primary aim of this study was to investigate if there was a relationship between preoperative talocalcaneal distance between the lateral talar process and calcaneus at the angle of Gissane and two-year postoperative outcomes in patients with flexible PCFD who underwent a reconstruction of their deformity. A secondary aim was to compare this cohort of patients to those who underwent a subtalar arthrodesis. Methods: Seventy-six consecutive patients >18 years old who underwent reconstruction of a flexible PCFD with (fusion cohort, n=40) or without (non-fusion cohort, n=36) a subtalar arthrodesis, had preoperative weightbearing CT (WBCT) scans, and had preoperative and ≥two-year postoperative PROMIS scores were included. Patient were excluded if they underwent a talonavicular fusion. Patients underwent a subtalar fusion if their chief complaint was lateral sinus tarsi pain. The talocalcaneal distance was measured on preoperative WBCT scans as the closest distance between the lateral process of the talus and the superior aspect of the calcaneus (Jeng et al 2018). Spearman correlation coefficients and multivariable regression analyses controlling for subtalar fusion were calculated between preoperative talocalcaneal distance and postoperative PROMIS scores. Due to the small sample sizes, descriptive statistics were reported as median and interquartile range (IQR), and differences between the non-fusion and fusion cohorts were determined using Mann Whitney U tests. Results: The median preoperative talocalcaneal distance for the non-fusion and fusion cohorts were 1.2 mm (IQR 0.75 mm, 1.7 mm) and 0.6 mm (IQR 0.1 mm, 1.1 mm, P=0.007), respectively. For the non-fusion cohort, there was no correlation between preoperative talocalcaneal distance and two-year postoperative PROMIS Physical Function (rho=0.198, P=0.891), Pain Interference (rho=-0.0136, P=0.891), and Pain Intensity (rho=-0.038, P=0.923). Similarly, there was no correlation between preoperative talocalcaneal distance and two-year postoperative PROMIS scores for the fusion cohort (all P>0.80). At two-years postoperatively, there was no difference in PROMIS scores between the non-fusion and fusion cohorts (all P>0.10) (Table 1). When controlling for talocalcaneal distance, there was no difference in postoperative PROMIS scores between the fusion and non-fusion cohorts (all P>0.30) (Figure 1). Conclusion: In PCFD patients undergoing a flatfoot reconstruction, there was no correlation between preoperative talocalcaneal distance and two-year postoperative patient-reported outcomes. Additionally, there was no difference in outcomes between patients who underwent a subtalar arthrodesis compared with patients who underwent a reconstruction even when controlling for talocalcaneal distance. Our results suggest that preoperative talocalcaneal distance is not an indication for subtalar arthrodesis. Additionally, patients indicated for a subtalar fusion for correction of their flexible PCFD deformity do not have worse outcomes than patients who did not undergo a subtalar arthrodesis regardless of preoperative talocalcaneal distance.

Peroneal Tendon Dislocation after Talus Fracture

Category: Trauma; Ankle Introduction/Purpose: Traumatic peroneal tendon dislocation (PTD) have been described in association with fractures of the pilon and calcaneus, however, the incidence of PTD after fractures of the talus has not been previously reported in the U.S. Methods: This was a retrospective review of adult patients with operatively treated fractures of the talus treated at a level I academic trauma center between 2007 and 2021. Charts, radiographs, and advanced imaging, when available, were reviewed for patient demographics, injury characteristics, and complications including diagnosis of peroneal tendon dislocation. Results: 126 patients with 128 talus fractures were included. Incidence of peroneal tendon dislocation was 21.1% (n=27). Peroneal rupture was found separately in 3 instances (2.3%). Among 27 cases of PTD, 14 (51.9%) were diagnosed based on advanced imaging, 7 (25.9%) by review of the operative report, and 6 (22.2%) based on both. 89.3% (n=25) of PTDs were diagnosed at time of injury, whereas 7.4% (n=2) were diagnosed several months after. Three PTDs underwent delayed surgical intervention due to delayed diagnosis (n=1), or missed dislocation by the surgeon, although evident on injury scans (n=2). Lateral process fractures had increased odds of PTD (OR 3.4, 95% CI: 1.3-8.9, p=0.012), as well as fractures with a positive fleck sign on radiographs (OR 14.3, 95% CI: 4.0-50.7, p=0.0001). Conclusion: Peroneal tendon dislocation with fracture of the talus is relatively common and was identified in one out of five fractures within the studied cohort. Surgeons and radiologists should be cognizant of this injury, especially in the setting of a lateral process fracture and a positive fleck sign.

Association of Radiographic Soft Tissue Thickness with Revision Total Ankle Arthroplasty Following Primary Total Ankle Arthroplasty: A Minimum of 5-year Follow-up

Category: Ankle; Ankle Arthritis Introduction/Purpose: The incidence of primary total ankle arthroplasty (TAA) is rising, with a corresponding increase in revision surgeries. Despite this, research on risk factors for revision TAA following primary TAA remains limited. Radiographic soft-tissue thickness has been explored as a potential predictor for outcomes in hip, knee, and shoulder arthroplasty, but its role in TAA has not been assessed. This study aimed to assess the predictive value of radiographic soft tissue thickness for identifying patients at risk of requiring revision surgery following primary TAA. Methods: A retrospective study was conducted on 323 patients who underwent primary TAA between 2003 and 2019. Radiographic measurements of soft tissue thickness were obtained from preoperative lateral weightbearing radiographs. Clinical variables including age, gender, body mass index (BMI), American Society of Anesthesiologists (ASA) classification, diabetes, smoking status, primary diagnosis, and implant type were recorded. Logistic regression analysis was used to assess the predictive value of soft tissue thickness and BMI for revision TAA. Results: The rate of revision surgery was 4.3% (14 out of 323 patients). Patients requiring revision had significantly greater tibial-tissue (3.54 vs. 2.48 cm; p=0.02) and talus-tissue (2.79 vs. 2.42 cm; p=0.02) thickness compared to those who did not require revision. Both the Tibial-Tissue thickness (Odds Ratio: 1.16 [1.12-1.20]; p < 0.01) and the Talus-Tissue thickness (Odds Ratio: 1.10 [1.05-1.15]; p < 0.01) measurements were significant predictors of revision TAA in multivariable logistic regression models. In contrast, BMI was not a significant predictor of revision TAA. The two metrics demonstrated excellent interrater reliability. Conclusion: Greater soft tissue thickness, as measured radiographically, was a better predictor of revision TAA compared to BMI. These findings suggest that radiographic soft tissue thickness may be a valuable tool for assessing the risk of the need for revision TAA following primary TAA. Further research is needed to validate these findings and explore the potential impact on clinical practice. Figure 1. Radiographical Assessment of Tissue Thickness The figure illustrates the method for obtaining the radiographic measurements on weightbearing lateral radiographs. (A) A line was drawn from the posterior distal tibia to the anterior distal tibia (Red Line), and the distance of the parallel segment extending from the anterior cortex of the tibia to the end of the soft tissue shadow was measured to determine the Tibial-Tissue thickness. A line was drawn from the lateral process of the talus to the head/neck junction of the talus (Yellow Line), and the distance of the parallel segment, extending from the head/neck junction of the talus to the end of the soft tissue shadow, was measured to determine the Talus-Tissue thickness.

Tightening and anti-loosening performance of spring washer connecting bolts

This paper investigates the tightening and anti-loosening performance of phosphated spring washers (i.e., PSW) and galvanized spring washers (i.e., GSW), considering three torques and comparing them with galvanized flat washers (i.e., GFW). Subsequently, a finite element model of the spring washer connecting bolt was established and validated, further investigating the force performance of the spring washer and the stress distribution in the thread area. Finally, a quantitative evaluation method for the anti-loosening performance of spring washers was proposed. The results show that the preload of GSW is maximum after the nut is tightened, and the loss of preload can be supplied by the flattened spring washer. At the same time, the inner ring of the spring washer is sticking, while the outer ring is sliding. Similarly, the contact pressure of the washer decreases radially. During the lateral vibration process, the decrease curve of preload consists of three stages: initial stage, stable stage, and loosening rotation stage. Specifically, GSW has the best anti-loosening performance, because the wear of the zinc layer increases friction. More importantly, the spring washer compensates for the gap between the nut contact surface during transverse vibration, ensuring uniform force distribution in the threaded area and effectively improving the anti-loosening performance.

Lateral buckling of umbilical cable armour under compression and bending

ABSTRACT With the increasing exploration and extraction of offshore oil and gas resources in deep-sea environments, the occurrence of lateral buckling has emerged as a predominant failure mode for umbilical cable armour. In this paper, a finite element model is developed to simulate the lateral buckling behaviour of umbilical cables. Additionally, the model test is conducted to compare and analyse the lateral buckling behaviour. The results demonstrate that the critical buckling load obtained from the numerical simulation closely corresponds to the experimental findings, affirming the reliability of the finite element model. This study investigates the wire shapes during lateral buckling process and examines the influence of various factors on lateral buckling. Notably, the formation of extrados and intrados resulting from umbilical cable bending significantly influences lateral buckling. This research provides valuable insights for the design and assessment of umbilical cables intended for deep-sea applications.

Chevron Bone and OS Penis in Dog: Structural and Functional Anatomy

The study was conducted to record the structural and functional anatomy of chevron bone and os penis in dogs. The chevron bone along with coccygeal vertebra and os penis were collected from four adult dogs by natural wet maceration technique. The chevron bone was alphabet capital “V” or “Y” shaped bone which consisted of three processes namely, two lateral process and one ventral process. The two lateral processes were articulated with the haemal process of coccygeal vertebrae to form haemal canal. The chevron bones functionally protect the middle coccygeal artery which has important clinical role in assessing the animal health. The os penis was a heterotrophic bone situated inside the penis. It was triangular in outline with a base, a body and an apex. The body consisted of three surfaces and three borders. The ventral surface was made up of deep urethral sulcus which accommodated and protected the urethra.

Non-osseous coalition of accessory anterolateral talar facet-A case series.

The accessory anterolateral talar facet (AALTF) is an anatomical variation that broadens the apex of the lateral talar process. Studies have associated it with other tarsal coalitions as a cause of rigid painful flatfoot. However, a coalition of an AALTF has never been described before. With the advent of MRI, there has been an increase in the detection of these accessory facets. Nevertheless, owing to its small size and unfamiliarity, it is not easily identified. Proper assessment of imaging findings and associated conditions is needed to confirm the diagnosis. Imaging findings in a series of four patients with painful rigid flatfoot revealed the presence of an AALTF with adjacent marrow edema and reduced joint space. This was associated with hindfoot valgus and subfibular impingement. Radiographic suspicion of a non-osseous coalition of AALTF was raised, which was confirmed intraoperatively in one of the patients and demonstrated on CT and MR images in the other patients. This case series presents rare cases of non-osseous coalition of AALTF with a new radiographic sign, the 'reverse tip of the iceberg sign'.

On the Neotropical Brincadorus: redescription, new species, taxonomic key and description of a related new genus (Insecta: Hemiptera: Cicadellidae: Deltocephalinae).

The Neotropical genus Brincadorus Oman, 1938 is redescribed, and five new species are described and illustrated. Brincadorus cruceno sp. nov., from Bolivia and Peru, can be differentiated by the long and slender aedeagus, with a pre-apical dorsal spine and apex curved downwards. Brincadorus gracilis sp. nov., from Ecuador and Peru, can be distinguished by the slender subgenital plates, aedeagus with slender shaft and basidorsal processes without a preapical tooth. Brincadorus limoncocha sp. nov. from Ecuador, can be differentiated by the robust aedeagus shaft, and bifurcate basidorsal processes. Brincadorus quincemil sp. nov., from Peru, can be distinguished by the bifurcate apex of the subgenital plates, and aedeagus basidorsal process with a preapical dorsal tooth. Brincadorus yanayacu sp. nov., from Ecuador, can be distinguished by the thorn-like apex of the subgenital plates, and short aedeagus, without processes. A key to species is provided, and a female is illustrated and described for the first time. New records for Ecuador and Peru are provided. A new genus that shares similarities with Brincadorus is described. Saltadorus gen. nov. can be distinguished by the smaller size, male pygofer with a pair of long inner lateral processes arising sub-basally on the dorsal region and extending beyond the pygofer apex, widely separated and elongated subgenital plates, and robust aedeagus with a conspicuous sclerotized gonoduct protruding from the atrium. Saltadorus blahniki sp. nov., from Peru, can be identified by the elongated male pygofer, and aedeagus without processes. Saltadorus dietrichi sp. nov., from Peru, can be distinguished by the shorter male pygofer, and aedeagus with a pair of subapical dorsal teeth. Based on the results of recent phylogenomic analyses, Brincadorus is removed from Bahitini and, along with Saltadorus, is considered unplaced to tribe in Deltocephalinae, pending further study.

A new genus of Gyponini (Hemiptera, Cicadellidae, Iassinae) with description of two new species from Brazil and key to genera of the Hecalapona complex.

Gracilipona gen. nov. is described and illustrated based on males and females of two new species from Brazil: G. tetrarama sp. nov. (type-species) from the states of Minas Gerais, Paraná, Rio de Janeiro, and Rio Grande do Sul, and G. birama sp. nov. from Bahia State. The new genus differs from other genera of the Hecalapona complex as follows: antennal ledge extending anteriorly below anterior margin of crown, forming an arched carina that connects the antennal ledges medially; pronotum moderately declivous; forewing with extra crossveins on distal third; protibia with dorsal surface flattened but not expanded, with lateral margins carinate; aedeagus with dorsal apodemes strongly developed and divergent and shaft with lateral processes arising from basal third; ovipositor with valvulae expanded subapically; first valvula with dorsal sculptured area short, mostly strigate, areolate near dorsal margin; and second valvula with a few rounded denticles subapically on dorsal margin. An updated key to genera of the Hecalapona complex and a discussion comparing Gracilipona gen. nov. with other related genera are provided.

Modeling of Plasma Nitriding of Austenitic Stainless Steel through a Mask

In this work, 2D simulations of stainless steel nitriding through a mask were performed with two configurations: with and without lateral adsorption under the mask, depending on the strength of the mask adhesion. The stress-induced diffusion and trapping–detrapping process are included as the main mechanisms of nitrogen mass transport. The main focus is on the analysis of the swelling process, which affects the expansion of the material. The surface concentration profiles and topographical profiles along the surface are calculated and compared with experimentally registered ones taken from the literature, and they show a good agreement. This allows for estimation of the values of model parameters. Because nitriding processes takes place in vertical and horizontal directions, the anisotropic aspect of nitriding are analyzed. It is shown that the adherence of the mask significantly influences the topographical profile and the anisotropy of nitriding, because in the case of a weakly adhered mask, a lateral adsorption process takes place under the mask. The influence of swelling and anisotropy in the case of pattern nitriding in small dimensions is discussed.

Lateral Transport Controls the Tidally Averaged Gravitationally Driven Estuarine Circulation: Tidal Mixing Effects

Abstract In classic models of the tidally averaged gravitationally driven estuarine circulation, denser salty oceanic water moves up the estuary near the bottom, while less dense riverine water flows toward the ocean near the surface. Traditionally, it is assumed that the associated pressure gradient forces and salt advection are balanced by vertical mixing. This study, however, demonstrates that lateral (across the estuary width) transport processes are essential for maintaining the estuarine circulation. This is because for realistic estuarine bathymetry, the depth-integrated salt transport up the estuary is enhanced in the deeper estuary channel. A closed salt budget then requires the lateral transport of this excess salt in the deeper channel toward the estuarine flanks. To understand how such lateral transport affects the estuarine salt and momentum balances, we devise an idealized model with explicit lateral transport focusing on tidally averaged lateral mixing effects. Solutions for the along-estuary velocity and salinity are nondimensionalized to depend only on one single nondimensional parameter, referred to as the Fischer number, which describes the relative importance of lateral to vertical tidal mixing. For relatively strong lateral tidal mixing (greater Fischer number), salinity and velocity variations are predominantly vertical. For relatively weak lateral tidal mixing (smaller Fischer number), salinity and velocity variations are predominantly lateral. Overall, lateral transport greatly affects the estuarine circulation and controls the estuarine salinity intrusion length, which is demonstrated to scale inversely with the Fischer number.

High-density vertical sidewall MoS2 transistors through T-shape vertical lamination

Vertical transistors, in which the source and drain are aligned vertically and the current flow is normal to the wafer surface, have attracted considerable attention recently. However, the realization of high-density vertical transistors is challenging, and could be largely attributed to the incompatibility between vertical structures and conventional lateral fabrication processes. Here we report a T-shape lamination approach for realizing high-density vertical sidewall transistors, where lateral transistors could be pre-fabricated on planar substrates first and then laminated onto vertical substrates using T-shape stamps, hence overcoming the incompatibility between planar processes and vertical structures. Based on this technique, we vertically stacked 60 MoS2 transistors within a small vertical footprint, corresponding to a device density over 108 cm−2. Furthermore, we demonstrate two approaches for scalable fabrication of vertical sidewall transistor arrays, including simultaneous lamination onto multiple vertical substrates, as well as on the same vertical substrate using multi-cycle layer-by-layer laminations.

Phylogenetic patterns in fossil and living billfishes (Istiophoriformes, Istiophoridae): evidence from the Central Mediterranean

AbstractStudy of the relationships of fossil and living billfishes is crucial for understanding the ecological drivers that control their biodiversity through time and how distributional patterns of extant populations may be affected by current abiotic events. Here we describe six istiophorid species that lived sympatrically in the central Mediterranean Sea during the Late Miocene, based on fossil istiophorids from Italy. Of these, †Pizzikoskerma salentina, †Sicophasma macrocanalata, †Makaira adensa and †Makaira cyclovata are new, while †M. belgica and †M. cf. colonense were described previously. The taxon Istiophorus is reported here for the first time in the Tortonian based on an unidentified species. We reconstructed the evolutionary direction of morphological traits by including the earliest known billfish, †Hemmingwaya sarissa, in our phylogenetic analysis as outgroup. A bill with circular cross‐section, 12 caudal vertebrae, a slim body and elongated first dorsal fin are shown to be plesiomorphic traits, while 13 caudal vertebrae, fusiform body, a shorter and pointed first dorsal fin, lateral process and quadrangular spines on the vertebral centra are traits associated with larger body sizes. The Makaira species described here have trabecular bone in the premaxilla forming the rostrum, an unusual pattern interpreted as an adaptation to reduce weight while simultaneously increasing body size. The fossil billfish assemblage suggests sea‐surface temperatures between 23°C and 24°C, much warmer than the modern central portion of the Mediterranean. The exquisite preservation of one specimen shows a trophic interaction between marlins and barracudas, the first direct evidence of predator–prey relationships in fossil istiophorids.

A Failure Analysis of the Long-Term Overturning Stability of Concrete Continuous Single-Column Pier Bridges Considering Creep and Overloaded Vehicles

Several single-column pier girder bridges have been involved in overturning accidents, resulting in significant economic losses and casualties, thus necessitating a risk assessment of the overturning stability. To date, the effect of structural degradation due to concrete creep on the long-term stability of bridges has not been demonstrated. In this study, a full-scale nonlinear analysis of the lateral overturning process of a collapsed concrete box girder based on the explicit dynamic finite element method (EFEM) was conducted to verify the reliability of the numerical method. An EFEM model incorporating concrete creep was developed to demonstrate the effect of structural degradation on the long-term stability of bridges. The synthesis overturning axis method (SOAM) was proposed to evaluate the long-term overturning stability of concrete continuous bridges, aiming to address the deficiencies in existing methods, particularly for curved bridges, and was compared with conventional methods. The results show that the variations in bearing reaction forces between curved and straight bridges under creep and self-weight are minimal, staying within 2%. An increase in the creep terminal coefficient results in the opposite trend in the ultimate vehicle weight of curved bridges and straight bridges, but fluctuations remain within 2%, indicating that long-term creep has a limited effect on the overall overturning stability. A failure analysis of 20 single-column pier bridges reveals significant differences in the ultimate vehicle weight between the rigid overturning axis method (ROAM) and folded overturning axis method (FOAM), with error ranges of −14.2% to 567.4% and −99.1% to −32.1%, respectively. The SOAM results have the smallest error range compared to those of the EFEM, with an error range of −38.8% to 33.9%. Despite these errors, the SOAM demonstrates a significant improvement in characterizing the trend and assessment accuracy of the overall overturning stability of single-column pier bridges.

Retraction Note: Vascularized Medial Femoral Condyle Bone Graft for the Management of an Acute Talar Neck Fracture: A Case Report

Background Management of talar neck fractures can be challenging due to the high rate of non- or malunion, avascular necrosis and post-traumatic arthritis, which has been attributed to the disruption of the bone’s tenuous blood supply during fracture displacement. Osseous medial femoral condyle (MFC) flaps are increasingly being used in the reconstruction of small bony defects due to recalcitrant non-union and avascular necrosis in the upper and lower limbs. We report a rare case of an MFC flap used in the reconstruction of an acute talar neck fracture. Case Presentation A 38-year-old male presented with multiple injuries following a motor vehicle accident, including an open comminuted talar neck and lateral process fracture, with dislocation of the subtalar and talocrural joints (Hawkins III). Initial exploration and debridement demonstrated a significant defect in the dorsal portion of the talar neck. Temporary stabilisation was achieved with Kirschner wires and the defect was packed with bone cement. Two weeks later, a MFC flap was harvested from the ipsilateral knee and tailored to fit the talar defect. Fixation was achieved with cannulated compression screws. At six weeks post-operative, all wounds had healed, a radiograph demonstrated a positive Hawkins sign and computed tomography showed incorporation of the flap. The patient had no donor site morbidity, and commenced weight bearing at 3 months postoperatively. Conclusion This is the first report demonstrating the viability of MFC flap reconstruction for the management of bony defects in acute talar neck fractures.

Study on compaction characteristics and mechanical model of dry crushing filling material under lateral confinement condition

The compaction characteristics and bearing capacity of dry filling materials in goaf have a significant influence on stope control and surface stability. Through acoustic emission monitoring and mechanical model analysis, a series of confined compression tests were conducted on crushed waste with varying particle sizes and Talbot coefficients. The deformation, fragmentation, and acoustic emission characteristics under corresponding working conditions were determined. The results indicate that the stress–strain curves of crushed stone with different particle sizes and Talbot coefficients exhibit similar nonlinear behavior during confined compression. However, the strain response varies with changing stress levels. By analyzing the slope change rate of the stress–strain curve, the lateral uniaxial compression process of waste rock can be divided into three deformation stages: rapid compression, stable crushing, and slow compaction. The compressive deformation characteristics of gravel differ based on particle size and Talbot coefficient. Specimens with a higher Talbot coefficient demonstrate stronger compressive resistance and weaker deformation resistance during initial compaction loading. Notably, the internal pressure structure strength is influenced by factors such as maximum particle size D, grading coefficient n, and particle size distribution continuity, rather than solely by the proportion of large particles. The evolution of acoustic emission signals and energy-time curve during waste rock confined axial compression synchronizes with the compaction process. Overall, compaction plays a critical role in maintaining the stability of goaf in dry crushed waste filling.

A new Trachyaspis-like pan-cheloniid turtle from the Bartonian of Kazakhstan

The article describes a fossil pan-cheloniid Protrachyaspis shorymensis gen. et sp. nov. from the Karakeshi, Kert, Kuyulus, and Monata localities of the Shorym Formation (Bartonian, middle Eocene), as well as unknown localities of the Mangyshlak Peninsula, Kazakhstan. In addition, the shell bones of small pan-cheloniids from the Kuyulus and Tuzbair localities of the Shorym Formation with some traits of P. shorymensis are described, which probably represent remains of juvenile specimens of this species. The new taxon is characterized by a number of features rarely found in pan-cheloniids, including serrated dentaries, distally displaced lateral process of the humerus, and deeply sculptured external carapace surface. These features indicate a likely herbivorous diet and pelagic lifestyle of the new pan-cheloniid. According to the results of the cladistic analysis, P. shorymensis is sister to the Neogene species Trachyaspis lardyi Meyer, 1843, from which it differs in the absence of ridges on the carapace in adult individuals, the configuration of the scutes on the parietal bone, and the structure of the plastron. The stratigraphic gap between the appearance of P. shorymensis and its sister T. lardyi suggests a long ghost lineage of members of this clade throughout the Bartonian – Aquitanian (ca. 20.7 million years) preceding the appearance of T. lardyi. In most trees, the P. shorymensis + T. lardyi clade is located within the Chelonini clade, which, taking into account the middle Eocene age of P. shorymensis, indicates the early divergence of crown cheloniids, previously established based on molecular data. The new taxon is similar to the fragmentary remains of pan-cheloniids with a sculptured external surface of the shell, previously described from four localities of the upper part of the Buchak and lower part of Kiev formations in the south of European Russia and Ukraine, which makes it possible to determine these materials as cf. Protrachyaspis sp., and probably extends the appearance of the P. shorymensis + T. lardyi clade back to the middle Lutetian.

Impact of Al Alloying/Doping on the Performance Optimization of HfO2-Based RRAM

Al alloying/doping in HfO2-based resistive random-access memory (RRAM) has been proven to be an effective method for improving the low-resistance state (LRS) retention. However, a detailed understanding of Al concentration on oxygen vacancy migration and resistive switching (RS) behaviors still needs to be included. Herein, the impact of Al concentration on the RS properties of the TiN/Ti/HfAlO/TiN RRAM devices is addressed. Firstly, it is found that the forming voltage, SET voltage, and RESET voltage can be regulated by varying the Al doping concentration. Moreover, we have demonstrated that the device with 15% Al shows the minimum cycle-to-cycle variability (CCV) and superior endurance (over 106). According to density-functional theory (DFT) calculations, it is found that the increased operation voltage, improved uniformity, and improved endurance are attributed to the elevated migration barrier of oxygen vacancy through Al doping. In addition, LRS retention characteristics of the TiN/Ti/HfAlO/TiN devices with different Al concentrations are compared. It is observed that the LRS retention is greatly enhanced due to the suppressed lateral diffusion process of oxygen vacancy through Al doping. This study demonstrates that Al alloying/doping greatly affects the RS behaviors of HfO2-based RRAM and provides a feasible way to improve the RS properties through changing the Al concentration.

Comparative Brain Morphology of Cleaning and Sponge-Dwelling Elacatinus Gobies.

Comparative studies of brain anatomy between closely related species have been very useful in demonstrating selective changes in brain structure. Within-species comparisons can be particularly useful for identifying changes in brain structure caused by contrasting environmental selection pressures. Here, we aimed to understand whether differences within and between species in habitat use and foraging behaviour influence brain morphology, on both ecological and evolutionary time scales. We used as a study model three species of the Elacatinus genus that differ in their habitat-foraging mode. The obligatory cleaning goby Elacatinus evelynae inhabits mainly corals and feeds mostly on ectoparasites removed from larger fish during cleaning interactions. In contrast, the obligatory sponge-dwelling goby Elacatinus chancei inhabits tubular sponges and feeds on microinvertebrates buried in the sponges' tissues. Finally, in the facultatively cleaning goby Elacatinus prochilos, individuals can adopt either phenotype, the cleaning or the sponge-dwelling habitat-foraging mode. By comparing the brains of the facultative goby phenotypes to the brains of the obligatory species we can test whether brain morphology is better predicted by phylogenetic relatedness or the habitat-foraging modes (cleaning × sponge dwelling). We found that E. prochilos brains from both types (cleaning and sponge dwelling) were highly similar to each other. Their brains were in general more similar to the brains of the most closely related species, E. evelynae (obligatory cleaning species), than to the brains of E. chancei (sponge-dwelling species). In contrast, we found significant brain structure differences between the cleaning species (E. evelynae and E. prochilos) and the sponge-dwelling species (E. chancei). These differences revealed independent changes in functionally correlated brain areas that might be ecologically adaptive. E. evelynae and E. prochilos had a relatively larger visual input processing brain axis and a relatively smaller lateral line input processing brain axis than E. chancei. The similar brain morphology of the two types of E. prochilos corroborates other studies showing that individuals of both types can be highly plastic in their social and foraging behaviours. Our results in the Elacatinus species suggest that morphological adaptations of the brain are likely to be found in specialists whereas species that are more flexible in their habitat may only show behavioural plasticity without showing anatomical differences.

Microtopographic Variation as a Potential Early Indicator of Ecosystem State Change and Vulnerability in Salt Marshes

As global climate change alters the magnitude and rates of environmental stressors, predicting the extent of ecosystem degradation driven by these rapidly changing conditions becomes increasingly urgent. At the landscape scale, disturbances and stressors can increase spatial variability and heterogeneity — indicators that can serve as potential early warnings of declining ecosystem resilience. Increased spatial variability in salt marshes at the landscape scale has been used to quantify the propagation of ponding in salt marsh interiors, but ponding at the landscape scale follows a state change rather than predicts it. Here, we suggest a novel application of commonly collected surface elevation table (SET) data and explore millimeter-scale marsh surface microtopography as a potential early indicator of ecosystem transition. We find an increase in spatial variability using multiple metrics of microtopographic heterogeneity in vulnerable salt marsh communities across the North American Atlantic seaboard. Increasing microtopographic heterogeneity in vulnerable salt marshes mirrored increasing trends in variance when a tipping point is approached in other alternative stable state systems — indicating that early warning signals of marsh drowning and ecosystem transition are observable at small-spatial scales prior to runaway ecosystem degradation. Congruence between traditional and novel metrics of marsh vulnerability suggests that microtopographic metrics can be used to identify hidden vulnerability before widespread marsh degradation. This novel analysis can be easily applied to existing SET records expanding the traditional focus on vertical change to additionally encapsulate lateral processes.