Distal Slope Research Articles

The oldest fossil record in the Iberian Peninsula; lower Ediacaran acritarchs of the Tentudía Formation, Ossa-Morena Zone (OMZ), Southwest Iberian Massif.

AbstractA diverse assemblage of acritarchs, that represents the oldest fossil record of the Iberian Massif, is described from Ediacaran metasedimentary rocks of the Tentudía Formation included in the Ossa Morena Zone stratigraphy (Southwestern Iberia). The microfossils found include Assesserium pyramidalis, Cavaspina sp. A, Ceratosphaeridium sp. A, Dictyotidium sp. A, Multifronsphaeridium sp. A, Schizofusa zangwenlongii, Tanarium megaconicum Tanarium sp. A, and Tanarium ? sp. B, This assemblage is diagnostic of the mainly lower Ediacaran Doushantuo-Pertatataka acritarchs (c. 633—565 Ma.). The lithological diversity of the Tentudía Formation suggests that these Ediacaran sedimentary rocks were deposited in a diversity of environments (platform, slope and submarine fans, including mass transport deposits in a back-arc basin that extended into the southern part of the Central Iberian Zone. The mass transport deposits are represented in the Ossa-Morena Zone by the Salvaleón Olistostrome composed by turbidites including chert clast probably derived from the shelf. The migration of the mass transport deposits into the Central Iberian Zone (Orellana Formation) indicates the migration of the back-arc basin depocenter. Later inversion of the back-arc basin is marked by the deformation of the lower Ediacaran sedimentary rocks Serie Negra Group in the Ossa-Morena Zone and Domo Extremeño Group in the Central Iberian Zone. In the upper Ediacaran-Terreneuvian a carbonate platform (Ibor Group) was established in the southern part of the Central Iberian Zone unconformably overlying the previously deformed Domo Extremeño Group. The most proximal areas in the Ossa-Morena Zone are represented by the Malcocinado Formation which overlies the Serie Negra Group and the distal areas of the southern part of the Central Iberian Zone are represented by distal shelf and slope deposits of the Cijara Formation, which are overlain by mass transport deposits that include carbonate olistolites from the Ibor Group (such as the Fuentes and Membrillar olistostromes).

Records of Burdigalian sea level and paleoclimate in the Maldives carbonate system

Tropical carbonate systems are valuable archives of paleoenvironments, as the carbonate growth is intimately affected by water depth and climatic conditions. Geochemical data from the Burdigalian interval in IODP Site U1468 in the Maldives, northern Indian Ocean, were integrated with sedimentological and paleontological data for a more detailed reconstruction of depositional history. Generally, the Sr/Ca values of slope sediments record highstand progradation in both sequence unit and whole Burdigalian interval, while the absence of higher Sr/Ca ratio close to the sequence boundary during the early Burdigalian could be related to the erosion of deeper-water sediments due to the activity of bottom current. From 20.5 to 19.1 Ma and from 17.9 to 17.2 Ma, nutrient level and productivity were moderately elevated due to the terrigenous input by the intensified South Asian Proto-Monsoon, which also helped cause more reducing conditions in the distal slope. Moreover, increased nutrient level facilitated the growths of calcareous algae and sponges, while it was not favorable for coral development. The elevated nutrient level, higher sea level, and monsoon-induced current contributed to the backstepping of the outer margin during the late Burdigalian. Our study shows an example on how a tropical carbonate platform evolved in response to the interplay of sea-level and paleoclimatic conditions. Findings are expected to be applicable to other tropical carbonate platforms.

Elucidating the hemodynamic impact of residual stenosis post-carotid artery stenting: A numerical study.

Residual stenosis (RS) and hemodynamics demonstrate a significant correlation with postoperative in-stent restenosis/thrombosis following carotid artery stenting (CAS). This study endeavors to elucidate the potential associations between RS and adverse postoperative hemodynamic factors. This study utilized 46 patient-specific carotid artery models post-stenting, which were categorized into two groups based on the presence of RS: the normal group (N, n=23) and the RS group (RS, n=23). A comparative analysis was conducted to evaluate the discrepancies in geometry and adverse hemodynamic parameters, alongside investigating the potential correlation between hemodynamic and geometric parameters. The results reveal that a higher reflux flow volume is discernible in the RS group during low-velocity phases of the cardiac cycle, concomitant with an augmented extent of areas exposed to oscillatory shear stress and extended particle residence time. Moreover, the adverse hemodynamic parameters exhibit a positive correlation with the degree of stent expansion, stent length in the common carotid artery (CCA), and the distal slope of the RS. The distal slope and tortuosity of RS significantly influence the development of adverse hemodynamic conditions post-stenting, exacerbating the hemodynamic environment near the stenosis. Interestingly, while an extended stent length in the internal carotid artery (ICA) region improves hemodynamics by reducing flow disturbance, a longer stent in the CCA significantly worsens these conditions. Hence, it is prudent to analyze the characteristics of the local lesion regions to optimize the strategy for stent implantation.

Dismantling of an isolated tropical carbonate platform through flank collapse and canyon erosion, Coral Sea, Northeast Australia

The steep slopes of carbonate platforms frequently display large-scale sediment destabilization features like rockfalls, mass transport complexes, and slope erosion. The processes and factors triggering such instabilities and how they interact are a matter of ongoing discussion. We use hydroacoustic, sedimentological, and seafloor imaging data to map and characterize slope instabilities and potential controlling factors at the flank of the isolated Tregrosse carbonate bank in the Coral Sea, northeast Australia. Erosion of gullies and submarine valleys is concentrated in slope segments with the platform rim at several 10s of meters of water depth, i.e. where there is potential for sediment transfer from the bank interior to the slope. Gravity core data indicate that most sediment export from the platform occurs during sea-level fall. The toe of slopes neighboring segments with a shallower platform rim are mostly characterized by mass-transport complexes of platform rim and upper slope rocks forming extended block fields. Distal slope areas are dismantled through submarine landslides resulting in scalloped head scarps. The basal detachment surface of these submarine landslides appears to be rooted in several 100 s of meters in the subsurface at a lithological heterogeneity, which is documented by a gamma-ray peak in the downhole logging data from Ocean Drilling Program Site 817. Our findings show that (1) canyon erosion, (2) platform rim and upper slope destabilization as well as (3) lower slope dismantling, largely act independently of each other to destabilize the flanks of the carbonate bank. The complexity of the carbonate platform dismantling processes and the corresponding controlling factors shown in this study should also be considered when interpreting seismic morphological data.

Evaluation of distal tibia slope in pilon fractures after surgical fixation

IntroductionAlteration of sagittal alignment during fracture fixation directly impacts ankle motion in dorsiflexion and plantarflexion. Previously research measured the anterior distal tibia angle (ADTA) in a normal healthy population. The null hypothesis for this study is that ADTA is restored to normal range following unstable pilon fractures. The aim of this study is to identify the range of the ADTA in distal tibia fractures after surgical fixation, compared to a previously published normal population. Material and MethodsA retrospective review of operative distal tibia fractures (AO/OTA classification 43A and 43C – 43B were excluded due to lower likelihood of fracture changing the ADTA) was performed. ADTA on lateral radiograph was measured as the angle relative to the tibia shaft. Results100 patients with post-operative radiographs that met inclusion criteria were analyzed. The average ADTA was 6.9° (⌠=4.62°) with a maximum slope of 19.2° (i.e. anterior orientation) and a minimum of -3.3° (i.e. posterior orientation). The uninjured population had an average ADTA of 6.0° (range -2.0°-14°, ⌠=3.0°). ConclusionThis analysis shows the average distal tibia sagittal alignment in the post-surgical group is similar to a normal, uninjured population. Large alterations in ADTA would directly impact the ankle in the plane of motion (i.e. negative ADTA would decrease ankle dorsiflexion). Considering ADTA as an objective intra-operative parameter optimizes sagittal plane alignment.

Glacial relief of the central part of the Kola Region

Improvement in quality of digital elevation models and satellite images of the Earth’s surface led to a tendency to interpret them without sufficient confirmation by geological research methods. At the same time, the geological data is critical for the interpretation of genesis of accumulative glacial landforms and regional landscape reconstruction during the last glaciation. The article provides a classification and geologic structure of the glacial relief of one of the key areas in the Kola region. New data were obtained using morphometric analysis of relief, geological, structural analysis of glacial landforms, petrographic analysis of coarse glacial deposits, and the study of lake sediments. Two bands of glacial accumulative relief were identified in the study area. The first band forms a parallel ridge relief on the southern slope of the Lovozero Tundra. It represents the formations of a lateral moraine formed at the edge of a glacier moving from the west to the east along the slope. Also a hummocky-ridge relief along the slopes of the Lovozero, Panskie, and Fedorova Tundras that consist of terminal moraines is included in this band. The moraines are composed of dislocated limno- and fluvioglacial deposits, dump and ablative moraines. The second band is formed by three subparallel chains of ridge-hummocky relief. They include folded and imbricated-thrust glaciotectonically deformed deposits. Fluvioglacial deposits are developed on the distal slope of the outer chain. Both bands of glacial relief are associated with formation of marginal landforms during two stages of glacial retreats. Analysis of deglaciation models of the last ice sheet in the Kola and adjacent regions and data on the position of known marginal glacial formations made it possible to compare the stages with the final episodes of the Luga (Karelian) and Neva (Syamozero) Stages. The information obtained reveals more details about the stages of development of the last ice sheet and the deglaciation pattern of the Kola region in the Late Glacial.

IN VIVO ACCURACY OF A NEW ROBOTICALLY ASSISTED SYSTEM FOR TOTAL KNEE ARTHROPLASTY: A PROSPECTIVE COHORT STUDY

IntroductionRecent technological advancements have led to the introduction of robotic-assisted total knee arthroplasty to improve the accuracy and precision of bony resections and implant position. However, the in vivo accuracy is not widely reported. The primary objective of this study is to determine the accuracy and precision of a cut block positioning robotic arm.MethodSeventy-seven patients underwent total knee arthroplasty with various workflows and alignment targets by three arthroplasty-trained surgeons with previous experience using the ROSA® Knee System. Accuracy and precision were determined by measuring the difference between various workflow time points, including the final pre-operative plan, validated resection angle, and post-operative radiographs. The mean difference between the measurements determined accuracy, and the standard deviation represented precision.ResultsThe accuracy and precision for all angles comparing the final planned resection and validated resection angles was 0.90° ± 0.76°. The proportion within 3° ranged from 97.9% to 100%. The accuracy and precision for all angles comparing the final intra- operative plan and post-operative radiographs was 1.95 ± 1.48°. The proportion of patients within 3° was 93.2%, 95.3%, 96.6%, and 71.4% for the distal femur, proximal tibia, femoral flexion, and tibial slope angles when the final intra-operative plan was compared to post-operative radiographs. No patients had a postoperative complication requiring revision at the final follow-up.ConclusionsThis study demonstrates that the ROSA Knee System has accurate and precise coronal plane resections with few outliers. However, the tibial slope demonstrated decreased accuracy and precision were measured on post-operative short-leg lateral radiographs with this platform.

The late Quaternary glacial depositional environment at Filey Bay, eastern England: Accretionary mechanisms for thick sequences of tills and stratified diamictons

Construction of the Holderness/Flamborough Head moraine belt on the East Yorkshire coast, England, records the oscillatory onshore flow of the North Sea Lobe of the British-Irish Ice Sheet from ~25.8 to ~19.7 ka BP, during which time a thick sequence of multiple diamictons and associated stratified sediments were emplaced. The sedimentology of a >40 m thick stratigraphy through the moraine belt at Filey Bay, in combination with local borehole records, is used here to reconstruct the depositional processes associated with glacier ice moving ca., 12 km onshore and damming the mouth of the Vale of Pickering, which resulted in the accumulation of an unusually thick and complex sequence of deposits traditionally classified as the “Filey till”. The base of the sedimentary sequence comprises stratified diamictons, which are interpreted as glacilacustrine deposits emplaced predominantly by sediment gravity flows in an ice-contact ‘mud apron’ on the distal slope of a subaqueous push ridge constructed in the earliest proglacial lake in Filey Bay; a vertical increase in coarse-grained lithofacies records increasing glacier proximity. Glacier overriding of the mud apron is recorded by a stacked sequence of tills that interdigitate with lake sediments inland. A zone of till-lake sediment interdigitation migrated first westward during North Sea Lobe advance and then eastward during its retreat, into and out of Glacial Lake Pickering, respectively. Multiple tills and intra-till stratified beds and lenses at the top of the sequence at Filey represent alternating deforming bed-sliding bed facies (subglacial traction tills and subglacial canal fills) associated with the construction of inset push moraines, constructed by sub-marginal incremental thickening or punctuated aggradation. This depositional scenario addresses the problems arising from genetic classifications of substantial accumulations of glacigenic diamictons as ‘till’ when modern analogues indicate only modest thicknesses of subglacial traction till beneath glaciers. Onshore thickening of glacigenic deposits through subaqueous push moraine construction and mud apron progradation is compatible with glacier surging behaviour, but not necessarily solely diagnostic of a surging North Sea Lobe during the last glaciation.

Comparison of imageless robotic assisted total knee arthroplasty and conventional total knee arthroplasty: early clinical and radiological outcomes of 200 knees.

The aim of this study was to compare the short term clinical and radiological outcomes of imageless robotic and conventional total knee arthroplasty (TKA) and to estimate the accuracy of the two techniques by analysing the outliers after TKA. We have evaluated 200 consecutive knees (158 patients), 100 knees undergoing robotic TKA, and 100 knees treated with conventional TKA. Demographic parameters like age, gender, body mass index, diagnosis and range of motion were obtained. Knee society score (KSS) and Knee society functional score (KSS-F) were used for clinical evaluation. Mechanical alignment (Hip-knee-ankle angle), proximal tibial angle (MPTA), distal femoral angle (LDFA) and tibial slope were analysed for radiological results and outliers were compared between both groups. Outliers were defined when the measured angle exceeded ± 3° from the neutral alignment in each radiological measurement on the final follow-up radiograph.The minimum follow-up was 6months (range, 6 to 18months). The preoperative mean HKA angle was 169.7 ± 11.3° in robotic group and 169.3 ± 7.3° in conventional group. There was significant improvement in HKA, LDFA, MPTA and tibial slope compared to the preoperative values in both the groups (p < 0.01). The number of HKA, LDFA and tibial slope outliers were 31, 29 and 37, respectively, in the conventional group compared to 13, 23 and 17 in the robotic group (p < 0.01). There was a significant improvement in the KSS and KSS-F functional scores postoperatively in both the groups (p < 0.01). However, there was no significant difference in the functional scores between the groups postoperatively (p = 0.08). This study showed excellent improvement with both imageless robotic and conventional TKA, with similar clinical outcomes between both groups. However, radiologically robotic TKA showed better accuracy and consistency with fewer outliers compared with conventional TKA.

Sexual dimorphism in the three-dimensional detailed crown structure of maxillary first premolars

Maxillary first premolars have a unique shape because of their curvature features, positional relationship of the cusps, and most prominent points, making them different from other teeth. This study aimed to quantitatively analyze the detailed three-dimensional morphometric structure of maxillary first premolars and sexual dimorphism. The study participants were 60 elementary and junior high school students (30 boys and 30 girls) in Japan. The distance between landmarks was measured using the three-dimensional coordinates of plaster casts, and the data collected was statistically analyzed. Sexual dimorphism was greater in the lingual cusp, showing greater variation in size than the buccal cusp. Boys exhibited significantly larger relative distances in the mesiodistal and buccolingual directions than girls; particularly, regarding mesiodistal diameter of the central groove, mesial slope of the buccal cusp, and distal slope of the lingual cusp. These results may be due to a slight difference in the timing of secondary enamel knots between boys and girls during the developmental stage, which was reflected in the sexual dimorphism of the completed teeth. Curvature features, cusp positions, and most prominent points were considered individual traits because they were not interrelated. Subtle differences during the developmental stage may lead to sexual dimorphism of the completed crown. Furthermore, the morphological characteristics of the maxillary first premolars may be related to their location in the dental arch.

SURFACE MORPHOLOGY AND DYNAMICS COASTLINE OF THE DZHARYLHACH SPIT DISTAL END

SURFACE MORPHOLOGY AND DYNAMICS COASTLINE OF THE DZHARYLHACH SPIT DISTAL END

Sequence stratigraphic filling model of the Cretaceous in the western Tabei Uplift, Tarim Basin, NW China

Abstract Cretaceous formation in the western Tabei Uplift is significant petroleum pay zone in the Tarim Basin, NW China. For the complex relationship between tectonic movement and depositional environment, sequence stratigraphic filling model of the whole Cretaceous formation has not been established yet. Using well logs and seismic data in this article, sequence stratigraphic evolution process and filling model of the Cretaceous are interpreted involving paleo-uplift, sedimentary and water-level. As a first-order sequence, the Cretaceous is subdivided into three second-order sequences, Shushanhe, Baxigai and Bashijiqike Formation. Shushanhe Formation is subdivided into three third-order sequences, KSQ1, KSQ2 and KSQ3 upwards; Baxigai Formation is considered as one single third-order sequence, KSQ4; Bashijiqike Formation is subdivided into three third-order sequences, KSQ5, KSQ6 and KSQ7 upwards. In the early KSQ1, paleo-uplift was aquatic. From KSQ1 to KSQ3, water-level raised and paleo-uplift moved upwards gradually; and water-level raising was faster than paleo-uplift ascending. The accommodations of these three sequences increased. Lacustrine facies mudstones and siltstones were onlap filling sequences towards Xiqiu Paleo-uplift. In the end of KSQ3, the whole region was subaqueous. The water-level and paleo-uplift in KSQ4 were easy steady, and the accommodation in KSQ4 was sustained. Delta depositional system began to prograde from depocenter to distal slope of paleo-uplift. In the high of Xiqiu Paleo-uplift, dominated sediments were fine grains for the sedimentary dynamic force. From KSQ5 to KSQ7 in the Bashijiqike Formation, water turned regression, paleo-uplift raised slowly and the accommodation reduced continually. Because of the progradation deltaic sandstones, downlap sequences were developed towards the Xiqiu Paleo-uplift. Exposed in the Early Paleogene, KSQ7 and part KSQ6 were truncated to form top unconformable boundaries. Established sequence filling model of the Cretaceous in the western Tabei Uplift provides important insights on the stratigraphic characteristics and in turn on the exploration potential of petroleum systems.

Application of remote sensing in the description of fluvial system in dryland: A case study of Golmud distributive fluvial system, Qaidam Basin, NW China

Distributive fluvial systems (DFS) are widespread in drylands in the northwestern China. Analyzing differences in fluvial morphology in drylands is beneficial for studying ancient rock records and the extra-terrestrial surface environment. The remote sensing image, characterized by real-time and possibility of repeated observations, is a vital tool for recording and comparing fluvial systems in drylands. Satellite remote sensing technology is a method of investigating fluvial morphologies. Due to the limited accuracy of satellite imagery, there are few reports on the detailed description of the fluvial system in drylands of NW China. We analyze the pattern of fluvial morphology changes in the Golmud distributive fluvial system (DFS) in the Qaidam Basin, northwestern China, using satellite remote sensing and unmanned aerial vehicles (UAV). Firstly, we use Google Earth real-time image data, historical image data, and radar digital elevation data to extract geomorphological information; then the UAV remote sensing image data were used to interpret fluvial network information; finally, we use the gray-scale differential vector method to describe the fluvial morphologies. Three zones have been identified in the Golmud DFS: the proximal, the medial, and the distal, by comparing the differences in topographic and geomorphic characteristics, fluvial morphologies, and sedimentary characteristics of the Golmud DFS. The proximal slope is higher than the other two zones, and the geomorphic features are mainly gravel gobi. The proximal fluvial morphologies are mainly large braided rivers, and sediments are more gravelly and less sandy. The medial slope is relatively small, and the geomorphic features are mostly oasis plains. The medial fluvial morphologies are mainly meandering rivers associating with braided rivers, and sediments are more sandy and less gravelly. The distal slope is the lowest, and the geomorphic features are mostly oasis plains, lakes, and marsh plains. The distal fluvial morphologies are mainly meandering rivers, and sediments are sandy and muddy. Comparison of the DFS from proximal to medial to distal in Golmud confirmed the potential of remote sensing image technology in identifying the fluvial morphologies and sedimentary facies distribution in dryland.

A radiographic model predicting the status of the anterior cruciate ligament in varus knee with osteoarthritis

PurposeThe study aims to investigate the accuracy of different radiographic signs for predicting functional deficiency of anterior cruciate ligament (ACL) and test whether the prediction model constructed by integrating multiple radiographic signs can improve the predictive ability.MethodsA total number of 122 patients from January 1, 2018, to September 1, 2021, were enrolled in this study. Among them, 96 patients were classified as the ACL-functional (ACLF) group, while 26 patients as the ACL-deficient (ACLD) group after the assessment of magnetic resonance imaging (MRI) and the Lachman’s test. Radiographic measurements, including the maximum wear point of the proximal tibia% (MWPPT%), tibial spine sign (TSS), coronal tibiofemoral subluxation (CTFS), hip–knee–ankle angle (HKA), mechanical proximal tibial angle (mPTA), mechanical lateral distal femoral angle (mLDFA) and posterior tibial slope (PTS) were measured using X-rays and compared between ACLF and ACLD group using univariate analysis. Significant variables (p < 0.05) in univariate analysis were further analyzed using multiple logistic regression analysis and a logistic regression model was also constructed by multivariable regression with generalized estimating models. Receiver-operating-characteristic (ROC) curve and area under the curve (AUC) were used to determine the cut-off value and the diagnostic accuracy of radiographic measurements and the logistic regression model.ResultsMWPPT% (odds ratio (OR) = 1.383, 95% confidence interval (CI) = 1.193–1.603, p < 0.001), HKA (OR = 1.326, 95%CI = 1.051–1.673, p = 0.017) and PTS (OR = 1.981, 95%CI = 1.207–3.253, p = 0.007) were shown as predictive indicators of ACLD, while age, sex, side, TSS, CTFS, mPTA and mLDFA were not. A predictive model (risk score = -27.147 + [0.342*MWPPT%] + [0.282*HKA] + [0.684*PTS]) of ACLD using the three significant imaging indicators was constructed through multiple logistic regression analysis. The cut-off values of MWPPT%, HKA, PTS and the predictive model were 52.4% (sensitivity:92.3%; specificity:83.3%), 8.5° (sensitivity: 61.5%; specificity: 77.1%), 9.6° (sensitivity: 69.2%; specificity: 78.2%) and 0.1 (sensitivity: 96.2%; specificity: 79.2%) with the AUC (95%CI) values of 0.906 (0.829–0.983), 0.703 (0.574–0.832), 0.740 (0.621–0.860) and 0.949 (0.912–0.986) in the ROC curve.ConclusionMWPPT% (> 52.4%), PTS (> 9.6°), and HKA (> 8.5°) were found to be predictive factors for ACLD, and MWPPT% had the highest sensitivity of the three factors. Therefore, MWPPT% can be used as a screening tool, while the model can be used as a diagnostic tool.

Improved Planktonic, Benthic Foraminiferal and Nannofossil Biostratigraphy Aids the Interpretation of the Evolution at Hole U1468A: IODP Expedition 359, the Maldives

Extended shallow carbonate platform, pelagic, and drift deposits were drilled during International Ocean Discovery Program (IODP) Expedition 359 in the Inner Sea of the Maldives. These sediments yield rich and well-diversified benthic, planktonic foraminiferal and nannofossil assemblages spanning from the early Oligocene to the Recent. We present here the shore-based revised integrated biostratigraphy of these microfossil groups at IODP Hole 359-U1468A together with the paleobathymetric reconstruction. Our data suggests the presence of a late Oligocene carbonate platform, marked by the shallowest water depths of the entire sequence of around 80 m. This carbonate platform sequence occurred from around 29 Ma, the extrapolated minimum age estimate, at least up to 27.5 Ma and possibly up to 25.4 Ma. Up the sequence, similar carbonate production conditions occurred until 22.5 Ma across the Oligocene–Miocene transition, equated at 23.04 Ma, with increased water depths &gt;120 m. Notably, in the time interval approximately from 24 to 21.5 Ma, orbitally induced sapropel layers indicate a change of open to restricted circulation. However, at around 22.5 Ma, pelagic deposition at a distal slope occurred with sedimentation rates of 3 cm/years. This initially occurred in water depths of &gt;350 m but gradually reached deposition in water depths of &gt;500 m, which persisted from 21.12 Ma until approximately the extrapolated age of 12.8 Ma. Sedimentation rates gradually increased to 10.5 cm/1000 years at around 450 m below sea floor, marking the initiation of the drift sequence as identified in seismic lines with an age estimate of 12.8 Ma. The initiation of the drift sequence is also marked by a drastic decrease in the preservation of benthic and planktonic foraminifera from good to very poor at around 12.8 Ma. The drift sequence essentially continued to the present day but was interrupted by two events: the deposition of distinct shallow water benthic shoals and a large hiatus. From 12.8 Ma, a shallowing upward bathymetry is suggested by the occurrence of shallow benthic foraminiferal assemblages that close to around 11.93 Ma reached a maximum water depth of 80 m. This shoal then prograded into the basin and persisted at least until 9.89 Ma. Basin conditions with water depths exceeding 500 m were re-established in the upper part of the sedimentary succession after a hiatus spanning approximately from 9.83 Ma to 2.39 Ma, implying that renewed open ocean conditions occurred in the Pliocene–Pleistocene part of the sedimentary record.

Infinity Ankle Arthroplasty Early Latin-America Experience and Patient Outcomes.

The promising data from Ankle Arthroplasty are consequence of the evolution of instruments and implants. Recent studies have shown good results in the short and intermediate follow-up, in addition to high patient satisfaction. The aim of this study is to present the results obtained with 49 cases treated with the Infinity total ankle prosthesis in 2 South America countries. This is a case series of 48 patients (27 women and 22 men), treated with 49 Infinity prostheses in Brazil and Colombia. They underwent surgical treatment between April 1, 2016, and January 18, 2020. We used the visual-analogue pain scale (VAS), the AOFAS score for ankle and hindfoot and the measurement of range of motion (ROM) in the pre- and post-surgical period. The radiological evaluation was performed on ankle radiographs in anteroposterior and lateral views, obtained in orthostasis, measuring the parameters suggested by Hintermann. Average follow-up was 4 years. VAS reduced from an average of 7.94 to 1.98; AOFAS increased from 28.02 to 83.16 and ROM increased from 11.45 to 28.08. Distal Tibial Slope is higher for higher improvements in VAS and lower for higher improvements in AOFAS and ROM. We observed 4 wound infections, 1 intra-op medial malleolus fracture. No bone cysts, tibial or talar components subsidence, polyethylene component wear or failure were observed. No salvation procedures were required in this series. This study results corroborates literature data showing great improvements in pain, functional pattern, and movement. Infinity Ankle Arthroplasty is a safe and reproducible procedure with good outcomes at a short-term follow-up. 4 - Case series.

The Chengjiang Biota inhabited a deltaic environment

The Chengjiang Biota is the earliest Phanerozoic soft-bodied fossil assemblage offering the most complete snapshot of Earth’s initial diversification, the Cambrian Explosion. Although palaeobiologic aspects of this biota are well understood, the precise sedimentary environment inhabited by this biota remains debated. Herein, we examine a non-weathered core from the Yu’anshan Formation including the interval preserving the Chengjiang Biota. Our data indicate that the succession was deposited as part of a delta influenced by storm floods (i.e., produced by upstream river floods resulting from ocean storms). Most Chengjiang animals lived in an oxygen and nutrient-rich delta front environment in which unstable salinity and high sedimentation rates were the main stressors. This unexpected finding allows for sophisticated ecological comparisons with other Burgess Shale-type deposits and emphasizes that the long-held view of Burgess Shale-type faunas as snapshots of stable distal shelf and slope communities needs to be revised based on recent sedimentologic advances.

Bivalves in the upper Miocene reef complex of Mallorca, Spain

Bivalves are common components in all the palaeoenvironments recognised in the Llucmajor Platform, the best-known outcrop of the Upper Miocene Mallorca Reef Complex. Shell concentrations of autochthonous elements with a low degree of taphonomical modification accumulated on the deep, quiet water bottoms from the basin to proximal reef slope. Low sedimentation presumably enhanced shell concentration as well as the development of clusters of superimposed slow-growing organisms, such as Neopycnodonte oysters that are typical of the basin and distal slope settings. Debris-flow beds of mostly disarticulated, fragmented and reoriented moulds of valves intercalate with the autochthonous shell concentrations in the basin and slope deposits as the result of downslope transport of bioclasts from shallower reef areas. Bivalve assemblages in the shallower-water reef palaeonvironments mainly con.sist of moulds of reworked fragments of disarticulated valves. Some crevice-dwellers, cemented and epibyssate forms were preserved in life position in the shelters created by coral colonies and blocks. The percentage of unbroken and articulated shallow endosedimentary bivalves is higher towards the protected inner-lagoon settings, in which Tellina specimens are the most characteristic components. We have identified 52 bivalve species belonging to 38 genera and recorded 19 additional species only identifiable at the generic level in all the sampled reef palaeonvironments.

Validation of the technique of TMJ 3D analysis based on computer tomography

The main aim of the study is devoted to optimization of the technique of 3D analysis of TMJ parameters, analysis of the causes of possible errors. The technique of 3D analysis of the width of the articular gap, the size of the condyle, the height and slope of the distal slope of the articular tubercle in the Avantis3D software (Russia) according to computed tomography is presented. The influence of repeated manual corrections of the condyles and articular fossa contours, shifting of the sectors measuring center, the position of starting point of the measurement sectors, and different algorithms for determining the longitudinal axis of the condyles on the accuracy of TMJ parameters detection. The study showed that any artificial displacement of the center of measurement sectors, which coincides with the longitudinal axis of the condyle, leads to significant value changes of the parameters. In this regard, the exact determination of the longitudinal axis of the condyles, independent of the human factor, is of particular importance. The greatest inaccuracy and variability of the results of measuring the parameters of the TMJ, as shown by the study, is associated with the possible manual correction of the contours of the surfaces of the condyles and articular fossa. The study did not find a noticeable difference in measurements if the sectors starts from the top of the articular tubercle or from the line parallel to the Frankfurt horizontal. As the optimal settings of the developed method was determined, it was used to determine the average values of the TMJ parameters for patients with a conventional «norm», as well as for patients with TMJ dysfunction. A noticeable and statistically significant difference was found between the groups only for upper and posterior width of the joint space. The average values of the intra-articular spaces width were justified, and can be used as the basis for the virtual assignment of the lower jaw reconstructive position for prosthetic or orthodontic treatment.

Topographical measurement of the attachments of the central band of the interosseous membrane on interosseous crests of the radius and ulna.

BackgroundTo suggest a reasonable isometric point based on the anatomical consistency of interosseous membrane (IOM) attachment in association with topographic characteristics of the interosseous crests, the footprints of the central band (CB) of the IOM on the radial and ulnar interosseous crests (RIC and UIC) were measured.MethodsWe measured the distance from the CB footprints from each apex of both interosseous crests in 14 cadavers and the angles between the forearm axis of rotation (AOR) and the distal slopes of the RIC and UIC in 33 volunteers.ResultsThe CB footprints lay on the downslope of both interosseous crests with its upper margin on average 3-mm proximal from the RIC's apex consistently in the radial length, showing normality (p>0.05), and on average 16-mm distal from the UIC's apex on the ulna without satisfying normality (p<0.05). The average angle between the UIC's distal slope and the AOR was 1.3°, and the RIC's distal slope to the AOR was 14.0°, satisfying the normality tests (p>0.05), and there was no side-to-side difference in both forearms (p<0.05).ConclusionsThe CB attached to the downslope just distal to the RIC's apex constrains the radius to the UIC that coincides with the AOR of the forearm circumduction, maintaining itself both isometrically and isotonically.