Absolute Age Research Articles

Age and Synchronization of Daphnia magna Affect Sensitivity to Teflubenzuron in Acute Standardized Toxicity Tests.

The standard Daphnia sp. acute toxicity test for assessing the adverse effects of chemicals on aquatic invertebrates stipulates the use of neonates that are ≤24 h old (hours post release [hpr]) at the start of the exposure. However, when one is assessing acute effects of chemicals interfering with endocrine relevant-processes such as molting, both age synchronization and absolute age can influence the test outcome, because the occurrence of molting and associated mortality is highly time specific. Hence, a 24-h age synchronization window may mask the real effects of these compounds. To explore the influence of age synchronization and absolute age in standard acute toxicity tests, we exposed D. magna from different synchronization windows and absolute ages (≤4, 4-8, 8-12, ≤12, and ≤24 hpr at the beginning of the exposure) to 0.5-12 µg/L of the chitin synthesis inhibitor (CSI) teflubenzuron (TEF) using the Organisation for Economic Co-operation and Development test guideline 202 (Daphnia sp. 48 h immobilization test). Our results show significant differences in 48-h median lethal concentrations between animals with a synchronization window of ≤4 hpr (2.9 µg/L) and longer synchronization windows such as ≤12 hpr (5.1 µg/L) and ≤24 hpr (16.8 µg/L). A concurrent decreasing trend in molting median effect concentrations was observed for the same synchronization windows: ≤4 hpr (4.0 µg/L), ≤12 hpr (5.9 µg/L), and ≤24 hpr (30.0 µg/L). Together, our results show that both synchronization and absolute age are determinant factors for the sensitivity of D. magna to TEF. A narrow synchronization window (e.g., ≤4 hpr) may provide a more conservative estimate of TEF toxicity and should be considered when one is performing standardized toxicity tests for molting-disrupting compounds such as TEF. Environ Toxicol Chem 2023;42:1806-1815. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

The effect of age on the induction dose of propofol for general anesthesia in dogs.

In people, the dose of propofol (DOP) required for procedural sedation and anesthesia decreases significantly with age. The objective of this study was to determine if the DOP required to perform endotracheal intubation decreases with age in dogs. Retrospective case series. 1397 dogs. Data from dogs anesthetized at referral center (2017-2020) were analyzed with three multivariate linear regression models with backward elimination using a combination of either absolute age, physiologic age, or life expectancy (ratio between age at the time of anesthetic event and expected age of death for each breed obtained from previous literature) as well as other factors as independent variables, and DOP as the dependent variable. The DOP for each quartile of life expectancy (<25%, 25-50%, 50-75%, 75-100%, >100%) was compared using one-way ANOVA. Significance was set at alpha = 0.025. Mean age was 7.2 ± 4.1 years, life expectancy 59.8 ± 33%, weight 19 ± 14 kg, and DOP 3.76 ± 1.8 mg kg-1. Among age models, only life expectancy was a predictor of DOP (-0.37 mg kg-1; P = 0.013) but of minimal clinical importance. The DOP by life age expectancy quartile was 3.9 ± 2.3, 3.8 ± 1.8, 3.6 ± 1.8, 3.7 ± 1.7, and 3.4 ± 1.6 mg kg-1, respectively (P = 0.20). Yorkshire Terrier, Chihuahua, Maltese, mixed breed dogs under 10 kg, and Shih Tzu required higher DOP. Status of neutered male, ASA E, and Boxer, Labrador and Golden Retriever breeds decreased DOP, along with certain premedication drugs. In contrast to what is observed in people, an age cut-off predictive of DOP does not exist. Percentage of elapsed life expectancy along with other factors such as breed, premedication drug, emergency procedure, and reproductive status significantly alter DOP. In older dogs, the dose of propofol can be adjusted based on their elapsed life expectancy.

Geochronology and formal stratigraphy of the Sturtian Glaciation in the Adelaide Superbasin

AbstractThe glaciogenic nature of the Yudnamutana Subgroup was first recognized over a century ago, and its global significance was recognized shortly after, with the eventual postulation of a global Sturtian Glaciation and Snowball Earth theory. Much debate on the origin and timing of these rocks, locally and globally, has ensued in the years since. A significant corpus of research on the lithology, sedimentology, geochronology and formal lithostratigraphy of these sequences globally has attempted to resolve many of these debates. In the type area for the Sturtian Glaciation, South Australia’s Adelaide Superbasin, the lithostratigraphy and sedimentology are well understood; however, formal stratigraphic nomenclature has remained complicated and contested. Absolute dates on the stratigraphy are also extremely sparse in this area. The result of these longstanding issues has been disagreement as to whether the sedimentary rocks of the Yudnamutana Subgroup are truly correlative throughout South Australia, and if they were deposited in the same time span recently defined for Sturtian glacial rocks globally, c. 717 Ma to c. 660 Ma. This study presents a large detrital zircon study, summarizes and compiles existing global geochronology for the Sturtian Glaciation and revises the formal lithostratigraphic framework of the Yudnamutana Subgroup. We show equivalence of the rocks that comprise the revised Sturt Formation, the main glaciogenic unit of the Yudnamutana Subgroup, and that it was deposited within the time span globally defined for the Sturtian Glaciation.

CHRONOLOGY AND DEVELOPMENT OF CRYOGENESIS IN LOESS-PALEOSOL SEQUENCE IN THE LOWER VOLGA REGION&lt;a href="#FN1"&gt;&lt;sup&gt;1&lt;/sup&gt;&lt;/a&gt;

The article presents the results of studying four sediment sections in the Lower Volga region that containing numerous traces of cryogenesis in Late Pleistocene subaerial deposits, represented by thin vertical wedges in loess and soils, involutions and wedges in alluvial deposits. In order to establish the stages of development and the boundaries of permafrost in the southeast of the East European Plain, morphology of cryogenic structures, morphoscopy and micromorphology of quartz grains were established, the coefficient of cryogenic contrast were calculated, and also absolute dating of deposits was performed. Five stages of cryogenesis development in the Late Pleistocene, which differed in type, scale of distribution, and conditions for the formation of cryogenic structures were established on the studied territory. The processes of cryogenic transformation of sediments occurred due to both seasonal freezing and the long-term development of a perennial permafrost zone. This determined the composition, structure and properties of loess-paleosol sequences and alluvial layers. The results obtained significantly refine the current understanding of the conditions for the formation of the Atelian deposits in the Lower Volga Region and the distribution of permafrost zone in the south of the East European Plain in the Late Pleistocene.

Pleistocene river diversions caused by large landslides in the western Pyrenees (Oria River drainage basin, N Spain)

AbstractRiver‐blocking landslides exert a deep impact on mountain range landscapes and the organization of catchments. A blocked river diverted to another watershed modifies both original and transferred drainage networks both up‐ and downstream. Using western Pyrenees examples, a geological and geomorphic framework with diagnostic criteria to detect river diversion by landslides is presented, including the identification of elbows of diversion, eroded divides, beheaded underfit rivers, diverted overfit rivers, reversed river segments and the landslides at fault. Some landslides caused the formation of lakes that overflowed upstream at catchment divide segments with elevations lower than those of blocking landslide tops. Unravelling the presence of fan deltas at distinct sites/elevations of palaeolake shores contributed as well to identification of river damming and later diversion episodes. Reconstruction of the sedimentary organization of river palaeovalleys and of their associated fluvial terraces and palaeoriver channels (some currently submerged by the Cantabrian Sea), along with the reconstruction of river profiles, analysis of bedrock and morphology of watershed divides, identify seven river diversions caused by landslides and 14 additional slides that variably constrained river basin dynamics in the area studied. The diverting slides have current areas between 0.06 and 12.3 km2 (thus including giant examples), thicknesses up to 300 m and translational–rotational rupture surfaces usually with low dip angles (3.5–12.3°). A combination of relative dating methods and published absolute ages suggests that diversion events occurred during the Quaternary. This study shows that river diversion by landslides can be significant in mountainous areas of moderate relief.

KURGAN SITES IN THE SAMARA RIVER BASIN: RESULTS OF INTERDISCIPLINARY RESEARCH

Four barrows (kurgans) were excavated in the basin of the river Samara in 2007—2008. Kurgan 1 near the village of Peschanka was located in its lower course. Three kurgans were situated near the mine «Stepova» in the middle course of Samara. Fifteen burials were discovered in the barrow 1 near the village of Peschanka. Three of them, graves 6, 7, 14 appear to be the earliest, exhibiting male burials and dating to the 38th to the 36th centuries BC (Eneolithic). The first burial mound was erected above these burials. Another two Eneolithic graves with skeletons of children were dug into the first kurgan. The construction of the Copper Age kurgan was completed after these two graves by digging a ditch around the mound.&#x0D; Among the four burials of the Yamna culture grave 15 was the oldest. However, its radiocarbon date 3626—3106 cal BC seems to be very early and is therefore debatable. But analyses of stable isotopes of nitrogen and carbon do not indicate a diet which might have caused a reservoir effect. The radiocarbon dates obtained for other burials in this kurgan correspond quite well with the relative chronology.&#x0D; The graves 10 and 11 date to the Yamna culture as well, but show characteristics in the funeral rites of its final phase. The calibrated time spans fall into the interval of 27—24 centuries cal BC. They coincide with the absolute dating of the Early Catacomb culture.&#x0D; C14-dates were also obtained for the catacomb graves 4 and 12. They agree well with the absolute and relative chronology of the developed phase of the Catacomb culture.&#x0D; The earliest kurgan (barrow 4) near the mine «Stepova» was built above the destroyed burials of the Eneolithic. In all three kurgans graves of the earliest phase of the Yamna culture were found. Interestingly, the identical organization of the space under and in the barrows and the very similar of details of the funeral rites indicate that all three barrows form a single burial complex. Probably, all graves were erected according to the same canonical norms during a relatively short time period. Most likely a single community used and formed these Early Bronze Age barrows. Unfortunately, the absence of radiocarbon dating makes it impossible to verify this hypothesis.&#x0D; The burials of the Catacomb culture discovered in the kurgans near the mine «Stepova» exhibit features of different phases and demonstrate the influence of various regions.&#x0D; The grave of a Kipčak warrior appears to be the most recent burial in kurgan 4 and dates to the time of the Golden Horde.

Pampa La Cruz: a New Mass Sacrificial Burial Ground during the Chimú Occupation in Huanchaco, North Coast of Peru

This article describes six sacrificial events carried out during the Late Intermediate Period and the beginning of the Late Horizon at Pampa La Cruz (PLC), located in the Moche Valley, North Coast of Peru. The archaeological context and circumstances in which the children and camelids were sacrificed at PLC are different from the previously investigated site of Huanchaquito – Las Llamas. PLC raises the question of whether the nature and the purpose of human sacrifice among the Chimú was more diverse and complex than previously thought. We discuss possible scenarios for the various sacrificial events identified at this site. Eighty AMS dates published here for the first time constitute the largest and most precise series of absolute dates for Chimú society obtained from one site, and by extension for the Late Intermediate Period in the entire coast of Peru.

Quantitative analysis of the structural evolution of salt diapirs and their impact on sediment routing and the architecture of deep-water channel reservoirs, Venus field offshore Angola

The interaction between deep-water channels and topography on the slope due to faulting, folding or diapirism is well known. However, most studies show only qualitative observations on the development of the structures. In the Block 31 area, offshore Angola, previous studies have established a chronostratigraphic framework where ten regional horizons can be assigned absolute ages from 89 Ma to 9.7 Ma utilizing biostratigraphic markers correlated to a global chronostratigraphic framework. This study focusses on the area around the Venus structure in Block 31 and over the 51-13.3 Ma time interval. The Venus structure is a salt-cored anticline with a syncline and a further salt-cored anticline to the east.Shortening analysis has been performed on 15 dip lines across the Venus structure for each of the ten horizons. During the focus interval, the Venus structure is divided into three areas; the crest of the structure which has a cumulative shortening of 680 m and interval shortening rates between 10 and 25 m/Myr, the northern low which has cumulative shortening of 180 m and interval shortening rates of 2–8 m/Myr and the southern low which has cumulative shortening of 450 m and interval shortening of 5–18 m/Myr. Over the same intervals eight main channel systems are identified (CS10-80). Each of the channels has been imaged on amplitude maps from spectral decomposition processed seismic data. The channel systems enter the study area from the east and take three routes down-dip; passing to the SW along the syncline between the two salt-cored anticlines or crossing the Venus structure through the northern of southern lows.Integrating the shortening analysis and the channel system routes shows that the channel systems are only able to cross the Venus structure through the southern and northern lows when the interval shortening rates in those areas are less than 10 m/Myr. At other times the channels are directed to the southwest along the synclinal axis. Off-set stacking of subsequent channel systems can be observed both at the entry point of the systems and through the northern and southern lows. This may be due to more subtle shifts in structurally controlled sea-floor topography or could also be due to stratigraphic compensational stacking. Within the CS20 system the sinuosity of higher order channel complexes and elements appear to be controlled by crestal faults extending into the southern low.

The Absolute Age of M92

The absolute age of a simple stellar population is of fundamental interest for a wide range of applications but is difficult to measure in practice, as it requires an understanding of the uncertainties in a variety of stellar evolution processes as well as the uncertainty in the distance, reddening, and composition. As a result, most studies focus only on the relative age by assuming that stellar evolution calculations are accurate and using age determinations techniques that are relatively independent of distance and reddening. Here, we construct 20,000 sets of theoretical isochrones through Monte Carlo simulation using the Dartmouth Stellar Evolution Program to measure the absolute age of the globular cluster M92. For each model, we vary a range of input physics used in the stellar evolution models, including opacities, nuclear reaction rates, diffusion coefficients, atmospheric boundary conditions, helium abundance, and treatment of convection. We also explore variations in the distance and reddening as well as its overall metallicity and α enhancement. We generate simulated Hess diagrams around the main-sequence turn-off region from each set of isochrones and use a Voronoi binning method to fit the diagrams to Hubble Space Telescope Advanced Camera for Surveys data. We find the age of M92 to be 13.80 ± 0.75 Gyr. The 5.4% error in the absolute age is dominated by the uncertainty in the distance to M92 (∼80% of the error budget); of the remaining parameters, only the total metallicity, α element abundance, and treatment of helium diffusion contribute significantly to the total error.

Supergene phases from ferruginous duricrusts: non-destructive microsampling and mineralogy prior to (U–Th) ∕ He geochronological analysis

Abstract. Interpreting the ages of supergene mineralogical phases in laterite is complex because they consist of polycrystalline mixtures of different phases at the microscopic scale that could be crystalized at different epochs. Among the geochronometers, the (U-Th)/He method on hematite and goethite is more often used, but ages can be difficult to interpret due to phases mixing. To resolve this issue, this study proposes a methodology for performing detailed mineralogical analysis of hematite and goethite single grains prior to their dating using the (U-Th)/He method. Strictly non-destructive mineralogy of single grains is not achievable by classical tools, such as conventional powder XRD (X-ray diffraction; requiring at least some milligrams of powder) or SEM (scanning electron microscopy; that can contaminate the grain by coating or fixing). Therefore, we performed X-ray diffraction patterns of single grains using high-flux X-ray beams from both a rotating anode (XRD_rotat) laboratory diffractometer and a synchrotron beamline (XRD_synch) and compared the results in order to design a method based on XRD_rotat only. For this purpose, two samples from the pisolitic facies of a Brazilian ferruginous duricrust (Alto Paranaíba region, Minas Gerais State, Brazil) were chosen because they presented a usual heterogeneity. Rietveld refinements of the XRD patterns obtained from both XRD_rotat and XRD_synch yielded similar results for the weight percentage ratio of the main phases and mean coherent domain sizes and less similar results for Al substitution rates, thus validating the XRD_rotat approach. No beam damage was observed when increasing X-ray exposure time, neither on XRD patterns nor on (U-Th)/He ages. Hence, sub-millimeter, undisturbed grains can be used to analyze the mineralogy of ferruginous duricrusts by XRD_rotat with a short exposure, and the same grains can subsequently be dated by (U-Th)/He geochronology analysis. The (U-Th)/He dating of pisolitic core and cortex grains also provided meaningful ages: they revealed two evolution phases of the ferruginous duricrust, which occurred at or before the Oligocene for the pisolitic core and middle Miocene for the pisolitic cortex, agreeing with the previous model for the development of pisolites. The mineralogy of single grains selected for dating is helpful for discussing the crystallization ages, and the high-flux XRD approach may be applied to other supergene mineral parageneses used for absolute dating.

Breaking with trends in forensic dating: A likelihood ratio-based comparison approach

Further steps toward understanding the time-related information contained within bloodstains found at the crime scene are rightly considered a top priority in forensic science. Contrary to widely held assumptions, the reason for the delayed exploitation of bloodstains dating methods in practice is not the lack of suitable analytical techniques for monitoring degradation processes. The problem lies in the variability of the environmental and circumstantial conditions, playing a vital role in the degradation kinetics of blood deposits. The present article demonstrates the possibility of breaking with current approaches based on absolute age estimations to finally answer time-centered questions in real forensic scenarios. The proposed novel framework for situating forensic traces in time is based on the likelihood ratio assessment of the (dis)similarity between the evidence decomposition and sets of reference materials obtained through supervised aging. In such a strategy, every dating procedure is constructed on a case-by-case basis to fit examined blood traces, thereby limiting the adverse influence of external factors on the validity of age estimations and providing a way for future crime scene implementation.

Orogenic gold mineralization in the Huangling region and its intimate tectonic linkage to the Neoproterozoic orogeny of South China

Gold mineralization types were rarely exposed in the Neoproterozoic accretionary-to-collisional orogen, particularly in China, throughout Earth’s history. The Huangling region in South China contains more than 70 gold deposits/occurrences hosted in Archean-Paleoproterozoic metamorphic rocks and Neoproterozoic granitic complexes. However, the absolute age of hydrothermal mineralization, genesis, and their relationship with regional-scale processes, such as tectonism, magmatism, and metamorphism, remains unclear. Therefore, in this study, we investigated three gold deposits (Shuiyuesi, Hongwucun, and Guaizigou) hosted in different lithological units from the northern, central, and southern regions of Huangling, respectively. We conducted detailed fieldwork and analyzed the hydrothermal apatite and monazite geochronology and Sr-Nd isotopic composition of these deposits. The gold mineralization is mainly hosted within sulfide-quartz veinlets, and it is structurally controlled by second-order NW- or NNW-striking faults of the first-order NW trending main fault zone. Gold is present in various forms, such as native gold, electrum, and petzite or in fine-grained pyrite as invisible gold co-precipitated with alteration mineral assemblages that include sericite, quartz, and hydrothermal apatite, and monazite. LA-ICP-MS U-Pb dating of the hydrothermal monazite and apatite for the Shuiyuesi deposit yielded two ages: 831 ± 2 Ma and 830 ± 23 Ma. These ages are consistent with the weighted mean 206Pb/238U age of 834 ± 3 Ma for apatite, obtained from the southern Guaizigou deposit within margin of error. Monazite and apatite dating of the Hongwucun gold deposit yielded younger ages of 810 ± 3 Ma and 800 ± 10 Ma, respectively. The new dates suggest that the gold deposits in the Huangling region underwent two distinct metallogenic episodes of gold mineralization during the Neoproterozoic, coeval with the temporal post-collisional mafic dykes, which postdated the regional metamorphism by ∼100 m.y, as indicated in the Huangling region after the peak period of collisional orogeny and in response to an extensional setting, possibly due to asthenosphere wedging. The Sr-Nd isotope of apatite and monazite (87Sr/86Sr: 0.69555–0.76244, εNd(t): −22.1–−2.9) and collective geochemical data indicate that ore-forming fluids are mainly consistent with magmatic sources with significant contribution from mantle materials. The results of the study suggest that the Huangling gold mineralization province is genetically related to Neoproterozoic post-collisional magmatism. Additionally, the region shares many characteristics of large orogenic gold provinces around the world, including alteration types, element associations, occurrence states of gold, and the evolution of orogenic belts, offering valuable new insights into the gold metallogeny of the early Neoproterozoic period, which is generally not known for its abundance of Au deposits.

The biotic and abiotic drivers of timing of breeding and the consequences of breeding early in a changing world

Abstract The decision of when to breed is an important determinant of individual fitness. However, despite a multitude of studies investigating the intraspecific relationship between timing of breeding and reproductive performance, less is known about why the strength of this relationship varies between species. Furthermore, environmental change has the potential to alter the relationship between lay date and fitness, but there is still a limited understanding of what mechanisms drive these differential responses to change environmental conditions. We propose that the potential effects of environmental change on the relationship between timing of breeding and fitness are dependent on 2 primary factors: (1) the potential constraints imposed by breeding early and (2) the drivers of higher fitness of early breeders. We first summarize multiple hypotheses proposed to explain why breeding early, either based on absolute date or relative to conspecifics, increases fitness. We then summarize the factors that may constrain when individuals initiate breeding, including limits on the ability to advance their lay date or extend the length of their breeding season under favorable conditions. Understanding constraints on the timing of breeding allows for the identification of obligate (single-brooded species that do not attempt to breed after a specific date) and facultative (predominantly multi-brooding species that have long breeding seasons) early breeding species that are likely differently affected by climate change. Finally, we propose a simple mathematical formula that incorporates the costs and benefits associated with early breeding to quantify how climate change could influence the benefits of early breeding and either mitigate or exacerbate the costs. Our cost-benefit approach provides a clear framework to predict how species may shift the timing of their breeding to maximize fitness in a changing world.

NEW RADIOCARBON DATES FOR THE MIDDLE CHALCOLITHIC PERIOD OF THE CENTRAL ZAGROS, IRAN

ABSTRACTAs one of the most extensive prehistoric entities of western Iran, Dalma culture belonging to the Zagros Chalcolithic, flourished in vast areas of the Central Zagros and Northwest Region of the country. This culture is defined essentially by its characteristic ceramic assemblages that show a marked uniformity in terms of technology, vessel forms, and painted designs throughout its territory. One of the main issues regarding this culture is its chronology, which was largely based on comparative studies, a few radiocarbon (14C) dates analyzed in the 1960s–1970s, or a few confusing thermoluminescence dates. In this paper, a series of 15 charcoal samples from a recent salvage excavation at Nad Ali Beig, a single-period site dated to Dalma period, is presented that provide the first reliable absolute dates for a part of the Middle Chalcolithic period of the Central Zagros region. Based on these new dates we may suggest that Dalma culture flourished between ca. 5200/5100–4600 BCE. Furthermore, based on these dates it is now possible to determine the order of appearance of different types of the Dalma culture ceramic assemblage, including the Ubaid-related painted buff ceramics.

Depleting soil nutrients through frequency and timing of hay cutting on floodplain meadows for habitat restoration and nutrient neutrality

Floodplain meadows support a high level of botanical diversity because the nutrient inputs from flood sediments are balanced by nutrient offtake via an annual hay harvest, leading to nutrient neutrality. This prevents a build-up of nitrogen (N) and phosphorus (P) and depletes excess nutrients, which mitigates eutrophication in catchment areas and prevents reductions of biodiversity through competitive exclusion.A replicated field trial was undertaken in floodplain meadows in central England, with the aim of comparing the nutrient offtake potential throughout the growing season with a single or a double-cut system, and determining when haymaking should occur to maximise nutrient offtake and nutritional value of the hay. Additionally, farmer perspectives were gathered to investigate the practicality of implementing a second hay cut.The results revealed that a single summer hay cut may be sufficient to balance nutrient inputs. However, a double-cut, where a second harvest replaces autumn grazing, has the potential to actively lower N and P levels, removing 8.69 g m−2 N and 0.80 g m−2 P. Maximising time between cuts in a double-cut system provides the greatest opportunity for nutrient removal.Temperature is a key driver of plant growth. The relationship between accumulated thermal time and calendar date in central England has advanced by around two weeks between 1961–1990 and 1991–2020. Delayed hay cutting under agri-environment scheme restrictions may be increasingly detrimental to botanical diversity with advancing seasons, due to lower nutrient removal under a single-cut system, and increased competitive exclusion. Taking a first cut at the mid-summer peak in offtake potential, currently 20–30 June in central England, and a second cut in the autumn offers an opportunity to deplete excess nutrients. Whilst farmers identify practical and financial concerns that may make a second cut prohibitive in some cases, this could be overcome by, e.g., demonstrating the higher-than-expected nutritional value of hay from a second cut.

The effects of x‐axis time compression on the visual analysis of single‐case data

AbstractSingle‐case design is a research methodology that entails repeated measurement to assess the influence of an independent variable on a dependent variable over time. Data collected in this manner are regularly analyzed using visual analysis of data displayed in a linear graph. Although there is agreement regarding critical elements of visual analysis, research has highlighted poor reliability between raters. One potential contributor to this poor reliability are variations in visual presentation of the data during construction of the linear graph. The current study sought to determine the potential effect of one common variation, scaling of the x‐axis by intervention session or by calendar date. Results of the study indicated a significant effect of x‐axis scaling, with data presented by session, rather than by calendar day, judged as reflecting larger intervention effects, Z = 1981, p &lt; .001. This effect was consistent across graphs displaying treatment effects of various magnitudes. Results of the study are discussed with the respect to the standardization of visual representation of single case data.

Investigating the Hubble Tension Through Hubble Parameter Data

The Hubble constant (H 0), which represents the expansion rate of the universe, is one of the most important cosmological parameters. The recent measurements of H 0 using the distance ladder methods such as type Ia supernovae are significantly greater than the CMB measurements by Planck. The difference points to a crisis in the standard model of cosmology termed Hubble tension. In this work we compare different cosmological models, determine the Hubble constant and comment on the Hubble tension using the data from differential ages of galaxies. The data we use are free from systematic effects as the absolute age estimation of the galaxies is not needed. We apply the Bayesian approach along with the commonly used maximum likelihood method to estimate H 0 and calculate the AIC scores to compare the different cosmological models. The non-flat cosmological model provides a higher value for matter density as well as the Hubble constant compared to the flat ΛCDM model. The AIC score is smaller for the flat ΛCDM cosmology compared to the non-flat model indicating the flat model a better choice. The best-fit values of H 0 for both these models are 68.7 ± 3.1 km s−1 Mpc−1 and 72.2 ± 4 km s−1 Mpc−1, respectively. Our results are consistent with the CCHP measurements. However, the flat model result does not agree with the SH0ES result, while the non-flat result is inconsistent with the Planck value.

The earliest directly dated saddle for horse-riding from a mid-1st millennium BCE female burial in Northwest China

The invention of the saddle substantially improved horseback-riding, which not only revolutionized warfare, but also eased long-distance speedy movement across Eurasia. Here we present the first detailed construction analysis and absolute age determination of a well-preserved soft leather saddle recovered from the tomb of a female deceased at the Yanghai cemetery site in the Turfan Basin at the eastern end of the Tian Shan mountains. Compared with the oldest known saddle from the Scythian Pazyryk culture site Tuekta barrow no. 1 (430–420 BCE) in north-western Altai, the Yanghai specimen radiocarbon dated to 727–396 BCE (95.4% probability range) is contemporaneous or possibly older. The saddle features the basic elements of soft saddle construction that are still used today: two stuffed, wing-shaped hides sewn together along the outer edges and separated by a central gullet-like spacer and lens-shaped support elements, resembling knee and thigh rolls of modern saddles. Being a masterful piece of leather- and needlework, it is, however, less complex compared to Scythian saddles from the 5th–3rd centuries BCE. Another specimen from nearby Subeixi site, which is also described in detail for the first time in the present study, much closer resembles the Pazyryk saddles in shape, size and structure. In Yanghai, equestrian paraphernalia appear in the grave assemblages during the entire burial period (ca. 1300 BCE to 200 CE), although in higher numbers only from ca. 300 BCE. In the same way, the burial of horses was not common until then. Despite the generally very good preservation of leather, only two saddles were discovered in Yanghai which makes them an exception rather than the norm and raises the question of whether these saddles were acquired from more specialized horse breeders, riders, and saddlers in the North.

Three-dimensional distribution of mass movement signals in disturbed Picea abies (L.) Karst.

Dendrogeomorphologic approaches enable annual absolute dating of various potentially hazardous geomorphic processes. This study tested the dating precision of three commonly used dendrogeomorphic approaches used for the extraction of geomorphic signals from the tree ring series of disturbed trees. The first approach is based on the onset of reaction wood occurrence, and the other two approaches are based on the detection of abrupt changes in tree ring eccentricity. Nine 165 cm long stems of maximally 27 year old Norway spruces (Picea abies (L.) Karst.) growing on unstable slope affected by mass movement events of known age were analysed. Several sampling directions on stems were analysed to reveal the best sampling strategy for each tested approach. The relationships between stem curvature and the dating precision of the approaches were also analysed. The results of dating precision showed crucial differences between the tested approaches. Tree stem curvature did not influence dating precision. Overall, we concluded that the approaches based on eccentric increments are less precise than those based on reaction wood analysis when juvenile P. abies trees that grow on landslide slope are sampled. The importance of this study is in providing new insight into dating precision by analysing the whole tree stems of trees influenced by mass movements. This is unique since the approaches based on eccentricity increments have not been previously tested in such a detail.

Short communication: The Wasserstein distance as a dissimilarity metric for comparing detrital age spectra and other geological distributions

Abstract. Distributional data such as detrital age populations or grain size distributions are common in the geological sciences. As analytical techniques become more sophisticated, increasingly large amounts of distributional data are being gathered. These advances require quantitative and objective methods, such as multidimensional scaling (MDS), to analyse large numbers of samples. Crucial to such methods is choosing a sensible measure of dissimilarity between samples. At present, the Kolmogorov–Smirnov (KS) statistic is the most widely used of these dissimilarity measures. However, the KS statistic has some limitations such as high sensitivity to differences between the modes of two distributions and insensitivity to their tails. Here, we propose the Wasserstein-2 distance (W2) as an additional and alternative metric for use in geochronology. Whereas the KS distance is defined as the maximum vertical distance between two empirical cumulative distribution functions, the W2 distance is a function of the horizontal distances (i.e. age differences) between observations. Using a variety of synthetic and real datasets, we explore scenarios where the W2 may provide greater geological insight than the KS statistic. We find that in cases where absolute time differences are not relevant (e.g. mixing of known, discrete age peaks), the KS statistic can be more intuitive. However, in scenarios where absolute age differences are important (e.g. temporally and/or spatially evolving sources, thermochronology, and overcoming laboratory biases), W2 is preferable. The W2 distance has been added to the R package, IsoplotR, for immediate use in detrital geochronology and other applications. The W2 distance can be generalized to multiple dimensions, which opens opportunities beyond distributional data.