Early Migration Research Articles

Antler Comb Production in the Settlement at Suceagu-Rădaia (Cluj County). A Contribution to the Study of the Cultural Contacts at the Beginnings of the Migration Period

The authors are presenting the antler combs discovered as part of the rural settlement at Suceagu – Rădaia, Cluj County. From the very beginning of the archaeological research, the numerous fragments of processed antler pointed towards the presence of a workshop similar to those already known at Bârlad – “Valea Seacă” or from other contemporary settlements in the Central-Eastern European region. The typological classification of the combs discovered here illustrated the presence of three types of combs having a single row of teeth and semi-circular handle, as well as double-sided combs. Of great significance is the zoomorphic decoration present on one of the combs belonging to one of the combs having a single row of teeth and semi-circular handle. The association of combs with a single row of teeth with double-sided ones represents a chronological as well as a cultural “marker” for the Early Migration period, other known analogies pointing towards the area of the Late Roman Pannonian Limes. Double-sided combs are found in a small number in the Sântana de Mureș – Černjachov environment, the chronology of these types of combs, as well as of other small finds identified in the Suceagu – Rădaia settlement, accounting for the presence of antler comb workshops here, during the chronological stages D1-D2. The presence of a production centre for double-sided combs at Pericei, a site positioned beyond the north-western limes of the former province of Dacia Porolissensis, represents a milestone that marks a possible route for cultural influences reaching towards the settlement at Suceagu – Rădaia. To conclude, the present study illustrates the existence of a cultural mixture between the local Sântana de Mureș – Černjachov milieu with northern cultural influences coming from the environment of the Germanic federates in the area of the Pannonian limes. Such a complex phenomenon should have its beginnings around AD 400, at a time when the important cultural environments of the Sântana de Mureș – Černjachov and Przeworsk cultures are starting to fade out of their existence. Mediation between the areas of southern Poland and north-western Transylvania took place, as indicated by the spatial distribution of numerous metal or ceramic artefacts through settlements in eastern Slovakia and north-eastern Hungary, areas that acted as real bridgeheads over the Carpathian Basin.

Women and Mining in Zambia: Opportunities and Challenges

The rise of urbanisation in colonial Zambia particularly on the Copperbelt province is associated with the discovery of minerals in the early 1900s. The widespread discovery of minerals and exploitation of the same minerals required labour both skilled and unskilled labour. Skilled labour was drawn from overseas while unskilled labour was available from the local population. During the colonial period, the predominant labour force on the mines were men while women were by law were not allowed to enter towns during the early years of urbanization or to take residence in urban areas anywhere in the country. Early researchers commented that early African migration to mine towns essentialised as men’s wage work, depended on agricultural and reproductive labour performed by women, who officially remained in rural areas. Local labour migrations were highly restricted and employment of women in urban areas was scarce or none existent in the initial stages of urbanisation.
 Skilled and none skilled labour for women employees on the mines initially did not exist in the colonial period because they (women) were not viewed as important labourers needed for production in the mines. This restriction of women in urban areas created a legacy of gender inequalities in almost all the sectors of labour employment and more so in the mining sector during the colonial period. Consequently, one can argue that since the colonial period to date, women have been a minority group in the mines occupying low positions in their majority compared to men and very few women hold executive positions in the mining sector.
 Employment during the colonial period was not easily found due to clear discrimination. The end result of this type of discrimination in employment resulted in few or no women at all in some instances in the mines. With passage of time, women were allowed into towns and on the mines but formal jobs for women were difficult to find. The current state of gender inequalities in the mines in Zambia today is a carryover from the colonial period. Currently, training institutions for mine workers such as universities, colleges and technical institute are still dominated by male students.
 The above situation eventually results into a gendered labour force in the mines with men occupying highly skilled jobs while women dominate the low skilled and non-skilled jobs in mining conglomerates. The current gender inequalities on the mines are historically embedded in the mines as patriarchal institutions owned and ran by the same men. Consequently, very few women are in the executive positions in mines and even very few do own mines.

Multi-Period Ore Exploitation in Upper Silesia, Central Europe

ABSTRACT We studied the abandoned mining field in southern Poland using high-resolution lidar images to distinguish the number of mining shaft remains and their morphological diversity. We identified 13,864 remains of mining shafts of various sizes (2–30 m in diameter) and diverse levels of denudation. This allowed us to select 13 mining shafts for detailed study. The radiocarbon dating of charcoal and peat from the shafts indicate three phases of exploitation in the study area: the Roman and early migration period (2nd century b.c.–6th century a.d.), the Middle Ages (6th–14th century a.d.), and the modern period (15th–17th century a.d.). The data on metal ore exploitation in the European Barbaricum is scarce and, in the study area itself, historical written sources indicate the onset of mining only in the 12th century a.d. Therefore, ore exploitation in the study area during the Roman period and early migration period, as well as in the early Middle Ages, is an unexpected result.

Developing a South Pacific tephra framework: Initial results from a Samoan Holocene sequence

ABSTRACTTephra preserved in sediments form useful isochronous marker layers, linking disparate geological, palaeoenvironmental and archaeological records. The application of tephrochronology is greatly enhanced through the detection of macroscopically invisible tephra (cryptotephra). Here, we identify two discrete cryptotephra in Samoan lake sediments, the first identification of cryptotephra in the region outside of New Zealand. Geochemical data suggest one ash layer is from a local Samoan source, providing the first data on an eruption of this age, adding to knowledge of the local volcanic record. The second has a distinctive rhyolitic glass composition, which matches either that of Raoul Island in the Kermadec Arc (1800 km south of Samoa), or two currently submarine volcanoes in the Tongan Arc, ‘Volcano F’ and Lateiki/Metis Shoal (550 and 700 km south of Samoa, respectively). In all possible source cases, this points to a regionally significant eruption of a Kermadec–Tongan volcano at ca. 10 000 a bp. The study marks the first step in the establishment of a South Pacific tephra framework that can be used to answer questions about the synchronicity of changes in hydroclimate, vegetation and early Polynesian migration patterns, as well as providing more information on the volcanic history of Pacific island volcanoes.

Migrating mule deer compensate en route for phenological mismatches

Billions of animals migrate to track seasonal pulses in resources. Optimally timing migration is a key strategy, yet the ability of animals to compensate for phenological mismatches en route is largely unknown. Using GPS movement data collected from 72 adult female deer over a 10-year duration, we study a population of mule deer (Odocoileus hemionus) in Wyoming that lack reliable cues on their desert winter range, causing them to start migration 70 days ahead to 52 days behind the wave of spring green-up. We show that individual deer arrive at their summer range within an average 6-day window by adjusting movement speed and stopover use. Late migrants move 2.5 times faster and spend 72% less time on stopovers than early migrants, which allows them to catch the green wave. Our findings suggest that ungulates, and potentially other migratory species, possess cognitive abilities to recognize where they are in space and time relative to key resources. Such behavioral capacity may allow migratory taxa to maintain foraging benefits amid rapidly changing phenology.

THE IMPORTANCE OF PRESS-FIT AND THREE-POINT FIXATION IN TREATING LARGE ACETABULAR DEFECTS WITH POROUS TANTALUM COMPONENTS

First-time revision acetabular components have a 36% re-revision rate at 10 years in Australia, with subsequent revisions known to have even worse results. Acetabular component migration >1mm at two years following revision THA is a surrogate for long term loosening. This study aimed to measure the migration of porous tantalum components used at revision surgery and investigate the effect of achieving press-fit and/or three-point fixation within acetabular bone.Between May 2011 and March 2018, 55 patients (56 hips; 30 female, 25 male) underwent acetabular revision THR with a porous tantalum component, with a post-operative CT scan to assess implant to host bone contact achieved and Radiostereometric Analysis (RSA) examinations on day 2, 3 months, 1 and 2 years. A porous tantalum component was used because the defects treated (Paprosky IIa:IIb:IIc:IIIa:IIIb; 2:6:8:22:18; 13 with pelvic discontinuity) were either deemed too large or in a position preventing screw fixation of an implant with low coefficient of friction. Press-fit and three-point fixation of the implant was assessed intra-operatively and on postoperative imaging.Three-point acetabular fixation was achieved in 51 hips (92%), 34 (62%) of which were press-fit. The mean implant to host bone contact achieved was 36% (range 9-71%). The majority (52/56, 93%) of components demonstrated acceptable early stability. Four components migrated >1mm proximally at two years (1.1, 3.2, 3.6 and 16.4mm). Three of these were in hips with Paprosky IIIB defects, including 2 with pelvic discontinuity. Neither press-fit nor three-point fixation was achieved for these three components and the cup to host bone contact achieved was low (30, 32 and 59%).The majority of porous tantalum components had acceptable stability at two years following revision surgery despite treating large acetabular defects and poor bone quality. Components without press-fit or three-point fixation were associated with unacceptable amounts of early migration.

Variations in the poly-histidine repeat motif of HOXA1 contribute to bicuspid aortic valve in mouse and zebrafish

Bicuspid aortic valve (BAV), the most common cardiovascular malformation occurs in 0.5–1.2% of the population. Although highly heritable, few causal mutations have been identified in BAV patients. Here, we report the targeted sequencing of HOXA1 in a cohort of BAV patients and the identification of rare indel variants in the homopolymeric histidine tract of HOXA1. In vitro analysis shows that disruption of this motif leads to a significant reduction in protein half-life and defective transcriptional activity of HOXA1. In zebrafish, targeting hoxa1a ortholog results in aortic valve defects. In vivo assays indicates that these variants behave as dominant negatives leading abnormal valve development. In mice, deletion of Hoxa1 leads to BAV with a very small, rudimentary non-coronary leaflet. We also show that 17% of homozygous Hoxa1−1His knock-in mice present similar phenotype. Genetic lineage tracing in Hoxa1−/− mutant mice reveals an abnormal reduction of neural crest-derived cells in the valve leaflet, which is caused by a failure of early migration of these cells.

Brown trout (Salmo trutta L. 1758) and Arctic charr [Salvelinus alpinus (L. 1758)] display different marine behaviour and feeding strategies in sympatry.

Brown trout (Salmo trutta L. 1758) and Arctic charr [Salvelinus alpinus (L. 1758)] tagged with acoustic transmitters migrated from fresh water to the sea mainly in May and June, but with large individual variation in migration timing. For S. trutta, large individuals (42-86 cm total length) migrated earlier in the season than small individuals (18-27 cm). For S. alpinus, no such pattern was found, likely because of the small size range of tagged fish (28-41 cm). S. trutta stayed longer at sea than S. alpinus (average 2 vs. 1 month). Early migrants of S. trutta stayed for a shorter period at sea than late migrants, whereas no such pattern was observed for S. alpinus. Large S. trutta moved quickly away from the river and spent average 3 days to reach a receiver line 20 km from the river mouth, whereas small S. trutta and S. alpinus migrating that far spent 2-3 weeks on the same distance. S. trutta utilized the entire fjord system and had a greater proportion of long-distance migrants (>20 km, 78% and 59% of large and small S. trutta, respectively) than S. alpinus (29%). S. alpinus mostly stayed in the inner fjord areas, and none were recorded in the outermost part of the fjord. The difference in the use of marine areas may be caused by variation in prey choice and spatial distribution of the preferred prey groups. Stable isotope analysis showed that S. trutta had been feeding at a higher trophic level than S. alpinus. S. trutta had mainly fed on marine fish and shrimps, whereas S. alpinus had large proportions of freshwater invertebrates in the diet, suggesting that the estuary with benthos and amphipods drifting from the river was an important feeding habitat for S. alpinus. In conclusion, major differences in habitat use, migration patterns and feeding strategies were found between sympatric anadromous S. trutta and S. alpinus while at sea.

In Search of Liberty: African American Internationalism in the Nineteenth-Century Atlantic World

In Search of Liberty sheds new light on Black freedom struggles during the nineteenth century, locating them within an international context that testifies to the resilience of those African Americans who forged new identities for themselves far beyond the shores of the United States, whether in Africa, the Caribbean, or Europe. The eleven essays in this collection are divided into four geographical sections. The first of these, North America, opens with Franco Paz and Harvey Amani Whitfield's essay on early Black migration to Nova Scotia, viewed through the harrowing case of Elizabeth Watson, an enslaved African American woman whose search for liberty resulted, perversely, in her reenslavement. Mekala Audain tackles another neglected frontier of liberty in her illuminating essay on Black migration from Louisiana to Spanish Texas during the early nineteenth century, while Thomas Mareite explores in telling detail the risk-laden experiences of Black refugees from slavery in early independent Mexico (1821–1836).

Akparabong and Yalla-Nkum Relations in the Middle Cross River Region, Nigeria

People and cultures migrating from one location to another is thought to be a long-standing historical trend. This is essentially true during the formative stages of nation-states. Internal and external factors more frequently induced the movement of a diverse range of people in groups or trickled them to habitations deemed more favourable, secure, or conducive to farming, settlement, hunting, and so on. Wars, slave raids, hostile neighborhoods, or the search for resources like water, salt ponds, and so on, constituted the push and pull factors of early migrations of populations. This paper considers the migrations and settlement of Yalla-Nkum and Akparabong and their impact on intergroup relations in Ikom, middle Cross River Region, from 1815–2007. The raison d’être and the factors of contacts and relations in determining the politics of Ikom have all been considered. The empirical phenomenological approach used in this study. Checking data is based on information obtained from informed informants. Documented sources also complement the primary data obtained. Findings show that ownership and management of scarce resources attract envy, hostility, and even resource conflicts among pre-colonial groups, thereby setting the pattern of relationships during the colonial era.

Ice and ocean constraints on early human migrations into North America along the Pacific coast

Founding populations of the first Americans likely occupied parts of Beringia during the Last Glacial Maximum (LGM). The timing, pathways, and modes of their southward transit remain unknown, but blockage of the interior route by North American ice sheets between ~26 and 14 cal kyr BP (ka) favors a coastal route during this period. Using models and paleoceanographic data from the North Pacific,we identify climatically favorable intervals when humans could have plausibly traversed the Cordilleran coastal corridor during the terminal Pleistocene. Model simulations suggest that northward coastal currents strengthened during the LGM and at times of enhanced freshwater input, making southward transit by boat more difficult. Repeated Cordilleran glacial-calving events would have further challenged coastal transit on land and at sea. Following these events, ice-free coastal areas opened and seasonal sea ice was present along the Alaskan margin until at least 15 ka. Given evidence for humans south of the ice sheets by 16 ka and possibly earlier, we posit that early people may have taken advantage of winter sea ice that connected islands and coastal refugia. Marine ice-edge habitats offer a rich food supply and traversing coastal sea ice could have mitigated the difficulty of traveling southward in watercraft or on land over glaciers.We identify 24.5 to 22 ka and 16.4 to 14.8 ka as environmentally favorable time periods for coastal migration, when climate conditions provided both winter sea ice and ice-free summer conditions that facilitated year-round marine resource diversity and multiple modes of mobility along theNorth Pacific coast.

FIVE-YEAR RSA RESULTS ASSESSING SUBSIDENCE AND ROTATION OF THE PARAGON HIP SYSTEM CONFIRMING IMPLANT STABILITY

Roentgen Stereophotogrammetric Analysis (RSA) is the gold standard for measuring implant micromotion thereby predicting implant loosening. Early migration has been associated with the risk of long-term clinical failure. We used RSA to assess the stability of the Australian designed cementless hip stem (Paragon TM) and now report our 5-year results.Fifty-three patients were prospectively and consecutively enrolled to receive a Paragon hip replacement. Tantalum beads were inserted into the bone as per RSA protocol and in the implant. RSA x-rays were taken at baseline 1–4 days post-surgery, at 6 weeks, 6 months, 12 months, 2 years, and 5 years. RSA was completed by an experienced, independent assessor.We reported the 2-year results on 46 hips (ANZJS 91 (3) March 2021 p398) and now present the 5-year results on 27 hips. From the 2-year cohort 5 patients had died, 8 patients were uncontactable, 1 patient was too unwell to attend, 5 patients had relocated too far away and declined. At 5 years the mean axial subsidence of the stem was 0.66mm (0.05 to 2.96); the mean rotation into retroversion was 0.49˚ (−0.78˚ to 2.09˚), rotation of the stem into valgus was −0.23˚ (−0.627˚ to 1.56˚). There was no detectable increase in subsidence or rotation between 6 weeks and 5 years. We compared our data to that published for the Corail cementless stem and a similar pattern of migration was noted, however greater rotational stability was achieved with the Paragon stem over a comparable follow-up period.The RSA results confirm that any minor motion of the Paragon cementless stem occurs in the first 6 weeks after which there is sustained stability for the next 5 years. The combination of a bi-planar wedge and transverse rectangular geometry provide excellent implant stability that is comparable to or better than other leading cementless stems.

Mercury’s formation within the early instability scenario

The inner solar system’s modern orbital architecture provides inferences into the epoch of terrestrial planet formation; a ∼100 Myr time period of planet growth via collisions with planetesimals and other proto-planets. While classic numerical simulations of this scenario adequately reproduced the correct number of terrestrial worlds, their semi-major axes and approximate formation timescales, they struggled to replicate the Earth–Mars and Venus–Mercury mass ratios (∼9 and 15, respectively). In a series of past independent investigations, we demonstrated that Mars’ mass is possibly the result of Jupiter and Saturn’s early orbital evolution, while Mercury’s diminutive size might be the consequence of a primordial mass deficit in the region (potentially the result of the growing Earth’s early outward migration). Here, we combine these ideas in a single modeled scenario designed to simultaneously reproduce the formation of all four terrestrial planets and the modern orbits of the giant planets in broad strokes. By evaluating our Mercury analogs’ core mass fractions, masses, and orbital offsets from Venus, we favor a scenario where Mercury forms through a series of violent erosive collisions between a number of ∼Mercury-mass embryos in the inner part of the terrestrial disk. We also compare cases where the gas giants begin the simulation locked in a compact 3:2 resonant configuration to a more relaxed 2:1 orientation and find the former to be more successful. In 2:1 cases, the entire Mercury-forming region is often depleted due to strong sweeping secular resonances that also tend to overly excite the orbits of Earth and Venus as they grow. While our model is quite successful at replicating Mercury’s massive core and dynamically isolated orbit, the planets’ low mass remains extremely challenging to match. Indeed, the majority of our Mercury analogs have masses that are 2–4 times that of the real planet. Finally, we discuss the merits and drawbacks of alternative evolutionary scenarios and initial disk conditions (specifically a narrow annulus of material between 0.7-1.0 au). We argue that the results of our N-body accretion models are not sufficient to break degeneracies between these different models, and implore future studies to apply further cosmochemical and dynamical constraints on terrestrial planet formation models.

СОЛЯРНАЯ МИФОЛОГИЯ ВОСТОЧНОЙ АЗИИ И ДРУГИХ РЕГИОНОВ

One of the main clusters of episodes in the mythologies of East and Southeast Asia describes the appearance of multiple suns, whose heat threatens life. The archer shoots down all the suns except the last one. This article examines the geographical distribution and frequency of combinations of these and other solar motifs. The dominant notion of the sun as a woman in the northeastern half of Eurasia only formed in the Holocene. It contrasts with variants typical of the Americas, Oceania, and Africa. The motifs of multiple suns, shooting at the suns, and rectifying the peculiarities of the original sun combined at the same time. A similar set is reflected in ancient Chinese monuments and in the folklore of China and Southeast Asia, but in America, these motifs are rarely interconnected. In southwest Eurasia, the sun in the form of a man or a woman occurs with almost equal frequency, which is characteristic of ancient mythologies in the Near East. In general, the percentage ratio of variants in southwest Eurasia is close to the world average, while in all other regions, it is skewed in favor of one of the variants. The myth of how the moon provoked the sun to eat its children was brought by early migrants from Africa to the Sunda subcontinent. At the end of the Pleistocene, a marine transgression displaced part of the population to the north, giving rise to the genes of the Malay Negritos and the myth of the sun-eaten children in Central India. Exclusive parallels between the Balkans and Shaanxi (“The Sun Refuses Marriage”), as well as between the Balkans, India, and Madagascar (“The Cancelled Cosmic Marriage”), remain unexplained.

The Influence of Peritoneal Dialysis Catheter Tip Design on Technique Survival: A Retrospective Observational Study.

The clinical practice guidelines for peritoneal access state that no particular peritoneal dialysis catheter (PDC) type has been proven superior to another. We present our experience with the use of different PDC tip designs. The study is a retrospective, real-world, observational, outcome analysis correlating the PDC tip design (straight vs. coiled-tip) and technique survival. The primary outcome was technique survival, and the secondary outcome included catheter migration and infectious complications. A total of 50 PDC (28 coiled-tip and 22 straight-tip) were implanted between March 2017 and April 2019 by using a guided percutaneous approach. The 1-month and 1-year technique survival in the coiled-tip PDC was 96.4% and 92.8%, respectively. Of the two coiled-tip catheters lost, one was a consequence of the patient having undergone live related kidney transplantation. The corresponding 1-month and 1-year technique survival with straight-tip PDC was 86.4% and 77.3%, respectively. When compared to straight-tip PDC, the use of coiled-tip PDC was associated with fewer early migration (3.6% vs. 31.8%; odds ratio (OR): 12.6; 95% confidence interval (CI): 1.41-112.39; P = 0.02) and a trend toward favorable 1-year technique survival (P = 0.07; numbers needed to treat = 11). Therapy-related complications noted in the study included peri-catheter leak and PD peritonitis. The PD peritonitis rate in the coiled-tip and straight-tip group was 0.14 and 0.11 events per patient year, respectively. The use of coiled-tip PDC, when placed using a guided percutaneous approach, reduces early catheter migration and shows a trend toward favorable long-term technique survival.

Distinguishing Different Categories of Migrants, Refugees, and Muslims in the Aftermath of the 2015-2016 Refugee “Crisis.” The Case of the Island of Kos (Greece)

This paper discusses local perceptions of different categories of migrants, refugees, and Muslims on the island of Kos in the aftermath of the 2015-2016 refugee “crisis.” It investigates how the presence of historical and earlier migrant and Muslim communities has facilitated the acceptance of new groups of Muslim migrants. It also reflects on how the arrival of new groups of Muslim migrants has affected the self-perception and perception of earlier and established Muslim communities. Methodologically, the paper is based on secondary sources, field research, and interviews conducted by the author on the island of Kos in June 2018.

Subgroups and differences of fixation in 3-part proximal humerus fractures.

This study aimed to determine the morphological differences of three-part proximal humerus fractures, the group in which plate screw fixation is most frequently used, and to evaluate the functional and radiological results of the methods applied for different subgroups. Twenty-nine patients (6 males and 23 females) with three-part proximal humerus fractures were in the study, with an average age of 64. The patients were in three groups according to their fracture types. Group 1 included eight patients with valgus impaction fracture. Group 2 included eleven patients with easily achieved stability after reduction. Group 3 consisted of ten patients with procurvatum varus angulation, a significant displacement between fragments, and in whom medial cortical continuity was not maintained without fixation. All patients underwent surgery with a minimally invasive deltoid split approach method and locked ana-tomic plate screw osteosynthesis. In group 1 patients, the space in the area where valgization is present in the head was filled with cortico-cancellous allografts. No grafting or metaphyseal compression took place in Group 2 patients. In group 3 patients, the metaphyseal compression technique was applied to the bone defect area. Cephalodiaphyseal angles (CDA) were measured at the postoperative and final follow-up. The constant Murley score made the functional evaluation. The patients were followed for an average of 27.6 months, and the union was present in all patients for an average of 3.6 months. Early screw migration was present in three patients, and late screw migration was in one patient. There were twenty-four excellent and 5 good results. CDA decreased from 139.42° to 136.13°. A statistically significant difference was present between the values of Groups 2 and 3 in the final control CDA of the groups. In this study, the functional scores of grafting stable valgus-impacted fractures and metaphyseal compression of unstable fractures with insufficient medial support were as good as stable 3-part fractures. Considering neer type 3 fractures should be evaluated with their subgroups, and fixation and stability-enhancing solutions specific to the groups are essential.

A new chronology from debiased crater densities: Implications for the origin and evolution of lunar impactors

The giant planets are believed to experience dynamic instability, delivering numerous impactors (asteroids, comets and leftover planetesimals) to the Moon. Dynamic simulations show that the impacts of leftover planetesimals decay much quicker than those from the main belt. Due to the relatively slow decay of early lunar impact flux directly inferred from observed crater densities, the dominant impactors were believed to have always been the main belt asteroids instead of rapidly decreasing leftover planetesimals. However, previously-derived densities are biased, with topographic degradation thought to increase the apparent density over time due to degradation-induced enlargement of crater diameter, coeval targets with various properties exhibiting different crater densities, and preferential erasure of small craters by the formation of larger ones. Here we establish a model with consideration of all these effects to derive crater densities on a competent-rock-like reference target (denoted as debiased crater densities), showing a constant flux prolonged back to ∼3.8 billion years ago (Ga) and a more intense earlier impact flux by a factor up to 100 compared with the standard production and chronology functions. We find that ancient (older than ∼3.8 Ga) craters were dominantly produced by leftover planetesimals rather than asteroids, consistent with the early migration of the giant planets.

Early migration in unicompartmental knee arthroplasty: a radiostereometric study of 26 patients with 24 months of follow-up.

Aseptic loosening, mainly caused by migration, is one of the most common indications for revisions in unicompartmental knee arthroplasty (UKA). In this study, we investigated the early migration of the Persona Partial Knee (PPK, Zimmer Biomet, Warsaw, IN), a cemented medial fixed-bearing unicompartmental knee prosthesis, and evaluated the clinical results. 26 primary PPKs were implanted. Radiographs were obtained direct postoperatively, at 6 weeks, 6, 12 and 24 months postoperatively. Migration of the femoral and tibial component was calculated using model-based radiostereophotogrammetric analysis (mRSA) in terms of translations and rotations. Patient-reported outcome measures (PROMs) were also registered. At 24 months postoperatively, we found low migration of both the femoral and tibial component in the first 6 months, after which both components stabilized. Only the rotation of the tibial component about the z-axis did not stabilize. All PROMs improved after 24 months compared with preoperative PROMs. The Persona Partial Knee shows low migration of both the femoral and tibial component and PROMs were improved at 24 months follow-up. Long-term follow-up is needed to investigate the performance of the prosthesis compared with other prostheses.

Orbital forcing of tropical climate dynamics in the Early Cambrian

According to modern atmospheric circulation models, the Intertropical Convergence Zone (ITCZ), as the Earth's meteorological equator, plays an essential role in the low-latitude hydrologic cycles. The limited availability of high-resolution tropical climate archives, especially from the Early Paleozoic Era, severely limits our understanding of ITCZ migration dynamics in deep time. Here we present high-resolution climate-proxy records (i.e., magnetic susceptibility (MS) and Zirconium/Aluminum (Zr/Al)) from tropical marine sediments of the ~526-million-year-old Qiongzhusi Formation in South China to investigate the link between orbitally forced insolation changes, ITCZ migration dynamics, and low-latitude climate processes. These orbital-scale variations in MS and Zr/Al series are interpreted as alternations between wet and dry cycles, controlled by monsoon intensity under the orbitally forced ITCZ-related paleo-Hadley Cell dynamics. Our results show that combined precession and obliquity orbital cycles had an impact on the Early Cambrian ITCZ migration. Specifically, the precession and obliquity forcing shift the mean position of the ITCZ latitudinally by changing the interhemispheric pressure contrasts, thus affecting the low latitude hydroclimate cycle. We report semi-precession cycles of 8.3–7.9 kyr, which were probably associated with the twice-annual passage of the ITCZ across the intertropical zone, consistent with the paleogeographical location of South China near the equator during the Early Cambrian. Observed ~1.1 – ~1.5 Myr eccentricity amplitude modulation (AM) cycles and ~ 1.0 – ~1.2 Myr obliquity AM cycles may provide geological evidence for the chaotic motion between Earth and Mars in the Early Cambrian. • Combined precession and obliquity cycles regulated the Early Cambrian ITCZ migration. • We report the semi-precession cycles of 7.9–8.3 kyr in the Early Cambrian. • Our study provides geological evidence for the chaotic Solar System in the Early Cambrian.