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Inferring the pattern and rate of past sea-level changes from uncertainty-prone proxy records requires formal statistical analyses, preferably in a hierarchical framework. The commonly used error-in-variables method treats the relative sea level as a collection of random variables drawn from the multivariate Gaussian distribution. However, this method does not make any use of prior information about the sea-level index points as constraints in the inferential process, thereby leading to anomalously large uncertainties for the time periods when observational data are absent. Here, a hierarchical Bayesian model of past sea-level changes is presented. Specifically, the stochastically varying relative sea level is modeled as a piecewise linear process with an additive independent Brownian increment arriving in a Gaussian fashion. The treatment of temporal uncertainties associated with the sea-level index points in the partially observed proxy records also differs from the existing methods. Instead of calibrating the radiocarbon ages individually, the corresponding calendar ages are treated as random variables and inferred recursively according to their temporal order. Illustrative studies using synthetic and real-world data demonstrate the promise of this model. • A Bayesian framework of relative sea-level change is provided. • Temporal ordering constraint is imposed on age modeling. • Sea-level changes are modeled as a Markov-Wiener process. • Utility of the model is demonstrated with synthetic and real-world data. [ABSTRACT FROM AUTHOR]

The use of cyclostratigraphy to reconstruct the timing of deposition of lacustrine deposits requires sophisticated tuning techniques that can accommodate continuous long-term changes in sedimentation rates. However, most tuning methods use stationary filters that are unable to take into account such long-term variations in accumulation rates. To overcome this problem we present herein a new multiband wavelet age modeling (MUBAWA) technique that is particularly suitable for such situations and demonstrate its use on a 293 m composite core from the Chew Bahir basin, southern Ethiopian rift. In contrast to traditional tuning methods, which use a single, defined bandpass filter, the new method uses an adaptive bandpass filter that adapts to changes in continuous spatial frequency evolution paths in a wavelet power spectrum, within which the wavelength varies considerably along the length of the core due to continuous changes in long-term sedimentation rates. We first applied the MUBAWA technique to a synthetic data set before then using it to establish an age model for the approximately 293 m long composite core from the Chew Bahir basin. For this we used the 2nd principal component of color reflectance values from the sediment, which showed distinct cycles with wavelengths of 10–15 and of ∼40 m that were probably a result of the influence of orbital cycles. We used six independent 40Ar/39Ar ages from volcanic ash layers within the core to determine an approximate spatial frequency range for the orbital signal. Our results demonstrate that the new wavelet-based age modeling technique can significantly increase the accuracy of tuned age models.

Precise radiocarbon (14C) dating of sedimentary sequences is important for developing robust chronologies of environmental change, but sampling of suitable components can be challenging in highly dynamic landscapes. Here we investigate radiocarbon determinations of different peat size fractions from six peat sites, representing a range of geomorphological contexts on the South Atlantic subantarctic islands of the Falklands and South Georgia. To investigate the most suitable fraction for dating, 112 measurements were obtained from three components within selected horizons: a fine fraction <0.2 mm, a coarse fraction >0.2 mm, and bulk material. We find site selection is critical, with locations surrounded by high-ground and/or relatively slowly accumulating sites more susceptible to the translocation of older carbon. Importantly, in locations with reduced potential for redeposition of material, our results show that there is no significant or systematic difference between ages derived from bulk material, fine or coarse (plant macrofossil) material, providing confidence in the resulting age model. Crucially, in areas comprising complex terrain with extreme relief, we recommend dating macrofossils or bulk carbon rather than a fine fraction, or employing comprehensive dating of multiple sedimentary fractions to determine the most reliable fraction(s) for developing a robust chronological framework. [ABSTRACT FROM AUTHOR]

Facial aging is an important problem of face recognition in missing children and automatic template update. As aging is a temporal process, it alters the facial appearance of the individuals. The sources of variations in facial appearance are caused by wrinkles (under eyes, forehead, around lips, and jawline), facial growth (cranial size and skull), and skin tone. The other factors such as health, lifestyle, and gender also impose variations in the aging process. Therefore, predicting facial aging with considering all those factors is a very difficult task. We present our 3D gender-specific aging model which automatically produces simulated images at age y by taking only one input image at age x irrespective of the pose and lighting conditions. The gender-specific aging model is constructed by various datasets (FG-NET, PCSO, Celebrities, BROWNS, Private), and its quality is evaluated with respect to various combinations of the datasets. We further fine-tune the aging model by changing the length of shape and texture eigenvectors and examine how these parameters affect the simulation results. Comparisons of the simulation results with state-of-the-art approaches as well as ground truth images demonstrate the effectiveness of the proposed methods. The subjective and objective evaluations are also carried out which emphasize the potential of our proposed gender-specific 3D aging model. [ABSTRACT FROM AUTHOR]

Tephra deposits correlated between nearby lakes provide the opportunity to improve age estimates of the sediment sequences, even if the ages of the tephras are previously unknown. We explore this potential using cryptotephras and visible tephra deposits in sediment cores from Upper and Lower Whitshed Lakes near Cordova, Alaska. Each tephra was described in terms of visual stratigraphy and shard morphology, and the major-oxide glass geochemistry was analyzed. Independent age models were developed for the cores using radiocarbon ages and profiles of short-lived radioisotopes for the near-surface sediments. Four tephras were correlated between the two lakes based on the magnitude and spacing of magnetic susceptibility peaks and glass major-oxide geochemistry. These correlations confirm agreement of the age models because the independently modeled confidence intervals overlap for each correlated tephra. The stratigraphic correlations were subsequently used to improve the age models by extracting the subset of possible age-model iterations that produce similar ages for each of the four correlated tephras at the two lakes. The iterations that agree within 25 years for each correlated tephra were used to create tephra-matched age models for both lakes, which narrowed the width of the 95% confidence intervals of the age models by 3% overall and reduced the uncertainty in age estimates of the correlated tephras by 34% on average. This synchronization technique may be useful in other studies that have multiple independently dated records with confident stratigraphic correlations. [ABSTRACT FROM AUTHOR]

Geochemically fingerprinted widespread tephra layers serve as excellent marker horizons which can directly link and synchronize disparate sedimentary archives and be used for dating various deposits related to climate shifts, faulting events, tsunami, and human occupation. In addition, tephras represent records of explosive volcanic activity and permit assessment of regional ashfall hazard. In this paper we report a detailed Holocene tephrochronological model developed for the Kamchatsky Peninsula region of eastern Kamchatka (NW Pacific) based on ∼2800 new electron microprobe analyses of single glass shards from tephra samples collected in the area as well as on previously published data. Tephra ages are modeled based on a compilation of 223 14 C dates, including published dates for Shiveluch proximal tephra sequence and regional marker tephras; new AMS 14 C dates; and modeled calibrated ages from the Krutoberegovo key site. The main source volcanoes for tephra in the region are Shiveluch and Kliuchevskoi located 60–100 km to the west. In addition, local tephra sequences contain two tephras from the Plosky volcanic massif and three regional marker tephras from Ksudach and Avachinsky volcanoes located in the Eastern volcanic front of Kamchatka. This tephrochronological framework contributes to the combined history of environmental change, tectonic events, and volcanic impact in the study area and farther afield. This study is another step in the construction of the Kamchatka-wide Holocene tephrochronological framework under the same methodological umbrella. Our dataset provides a research reference for tephra and cryptotephra studies in the northwest Pacific, the Bering Sea, and North America. [ABSTRACT FROM AUTHOR]

Joining the European Union club implies, among many other policy changes, full integration of Romania’s economy into EU’s customs union. This is expected to have significant implications for domestic farmers and food processors. The paper constructs a single-country Applied General Equilibrium (AGE) model to investigate the impact of tariff border adjustments on changes in relative prices, production and trade patterns associated with fifteen local agro-food activities. Moreover, the modelling work identifies those agro-food sectors that have the potential to benefit the most from EU enlargement in terms of output effects given that Romanian producers are capable of fully responding to the incentives provided with integration. These mainly include (bovine) live animals and meat products, sugar, and cereal grains. Agro-food trade with EU intensifies in particular for those commodities for which trade restrictions are still substantial prior to accession. However, the magnitude of changes is relatively small due to the weak integration of domestic agro-food sectors into international trade structures. The AGE model also predicts static welfare gains of 0.65 percent of GDP equivalent variation. These seem to be more associated with better access to EU markets and increased export prices, and less with the preferential unilateral elimination of tariffs or their adjustment to EU’s external levels. The model assumptions are highly theoretical and the model structure does not reflect with fidelity the workings of an economy in transition. Nonetheless, it does represent a solid base upon which further improvements could be added and structural transitional issues could be attached to more accurately predict potential outcomes.

The ages of critical periods in the geological record of the Earth have to be determined and attached uncertainties quantified as precisely and accurately as possible. This study tries to find an optimal strategy for sampling, for both biochronology and high-precision U–Pb analysis of zircon from ash beds, and for the selection and statistical treatment of geochronological data. This strategy is applied to the case of the Early–Middle Triassic boundary (EMTB) in the southern Nanpanjiang Basin in South China, aiming to obtain the most accurate age information for this boundary with an associated uncertainty. The EMTB has been located in a sedimentary section near Monggan, Guangxi, South China, which permitted tight correlation between conodont biozones, the carbon isotopic record, and high-precision zircon U–Pb data from volcanic ashes. Two residual maximal horizons were defined using characteristic associations of conodont species, accurately bracketing the EMTB. The lower and upper age limits of these horizons, as well as the first occurrence (FO) of the base Middle Triassic index fossil Chiosella timorensis , were numerically calibrated by high-precision chemical abrasion, isotope dilution, thermal ionization mass spectrometry (CA-ID-TIMS) U–Pb dates. Volcanic zircon in the analyzed ash beds reveals complex system behavior, in particular (i) unresolved lead loss after chemical abrasion, and (ii) pre-eruptive growth and/or recycling of zircon crystals, leading to excess scatter in 206 Pb/ 238 U dates and to violations of the stratigraphic sequence. A sufficiently high number of closely spaced ash samples (N) and of U–Pb analyses per sample (n) promotes recognition of such complications. Two different age models were constructed from weighted mean 206 Pb/ 238 U dates, comparing smoothing cubic spline and Bayesian interpolation approaches. The statistical treatment of the combined datasets allows quantification of the lower and upper limits and associated uncertainties of the two conodont biozones as well as of the FO of C. timorensis . The age for the EMTB is calculated from combined interpolated data at 247.05 ± 0.16 Ma. The age model derived from Bayesian interpolation is considered to be more adapted to the present case, where discontinuous changes in sedimentation rates are expected to be important. The smoothing spline represents a more parsimonious model, producing a simpler solution in terms of smoothness, but the model assumptions are too strong for many geological problems. The additional freedom in constructing the Bayesian interpolating curve presumably leads to more realistic, albeit larger confidence intervals. [ABSTRACT FROM AUTHOR]